Yuri Skoromets
In engines familiar to us internal combustion the initial link - pistons, reciprocate. Then this movement, with the help of the crank mechanism, is converted into rotational. In some devices, the first and last link make the same kind of movement.
For example, in a motor-generator, there is no need to first convert the reciprocating motion into rotational motion, and then, in the generator, to extract the rectilinear component from this rotational motion, that is, to do two opposite transformations.
The modern development of electronic conversion technology makes it possible to adapt the output voltage of a linear electric generator for the consumer, this makes it possible to create a device in which a part of a closed electric circuit does not rotate in a magnetic field, but reciprocate with the connecting rod of an internal combustion engine. Diagrams explaining the principle of operation of a traditional and linear generator are shown in Fig. 1.
Rice. 1. Diagram of a linear and conventional electric generator.
A conventional generator uses a wire frame that rotates in a magnetic field and is driven by an external propulsion device to generate voltage. In the proposed generator, the wire frame moves linearly in a magnetic field. This small and unprincipled difference makes it possible to significantly simplify and reduce the cost of the propulsion unit if an internal combustion engine is used as it.
Also, in a reciprocating compressor driven by piston engine, the input and output links are reciprocating, Fig. 2.
Rice. 2. Diagram of a linear and conventional compressor.
Advantages of the linear motor
- Small dimensions and weight, due to the absence of a crank mechanism.
- High MTBF due to the absence of a crank mechanism and due to the presence of only longitudinal loads.
- Low price, due to the lack of a crank mechanism.
- Manufacturability - only non-labor-intensive operations, turning and milling are required for the manufacture of parts.
Compression cycle. The piston moves from piston bottom dead center to piston top dead center, overlapping the purge ports first. After the piston closes the purge ports, fuel is injected and the combustion mixture is compressed in the cylinder. In the pre-launch chamber, a vacuum is created under the piston, under the action of which air enters the pre-launch chamber through the opening valve.
2. The stroke of the working stroke. When the piston is positioned near top dead center, the compressed working mixture is ignited by an electric spark from a candle, as a result of which the temperature and pressure of the gases increase sharply. Under the action of thermal expansion of gases, the piston moves to the bottom dead center, while the expanding gases do useful work. At the same time, the piston creates high pressure in the pre-start chamber. The pressure closes the valve, thus preventing air from entering the intake manifold.
Ventilation system
During the working stroke in the cylinder, Fig. 6 working stroke, the piston, under the action of pressure in the combustion chamber, moves in the direction indicated by the arrow. Under the influence of excess pressure in the pre-start chamber, the valve is closed, and here the air is compressed to ventilate the cylinder. When the piston (compression rings) reaches the purge ports, Fig. 6 ventilation, the pressure in the combustion chamber drops sharply, and then the piston with the connecting rod moves by inertia, that is, the mass of the moving part of the generator plays the role of a flywheel in a conventional engine. In this case, the purge windows are fully opened and the air compressed in the pre-inlet chamber, under the influence of the pressure difference (pressure in the pre-launch chamber and atmospheric pressure), purges the cylinder. Further, with a working cycle in the opposite cylinder, a compression cycle is carried out.
When the piston moves in compression-compression mode, Fig. 6 compression, the purge ports are closed by the piston, liquid fuel is injected, at this moment the air in the combustion chamber is under a slight excess pressure at the beginning of the compression cycle. With further compression, as soon as the pressure of the compressed combustible mixture becomes equal to the reference pressure (set for the given type of fuel), an electric voltage will be applied to the spark plug electrodes, the mixture will ignite, the working cycle will begin and the process will repeat. In this case, the internal combustion engine consists of only two coaxial and oppositely located cylinders and pistons, mechanically connected to each other.
Rice. 6. Ventilation system of the linear motor.
The drive of the fuel pump of a linear electric generator is a cam surface sandwiched between the pump piston roller and the pump housing roller, Fig. 7. The cam surface reciprocates with the connecting rod of the internal combustion engine and moves the piston and pump rollers apart at each stroke, while the pump piston moves relative to the pump cylinder and pushes a portion of fuel towards the fuel injection nozzle at the beginning of the compression cycle. If it is necessary to change the amount of fuel ejected in one stroke, the cam surface is rotated relative to the longitudinal axis. When the cam surface is rotated relative to the longitudinal axis, the pump piston rollers and the pump body rollers will move apart or move (depending on the direction of rotation) at different distances, the piston stroke of the fuel pump will change and the portion of the ejected fuel will change. The rotation of the reciprocating cam around its axis is carried out using a stationary shaft, which engages with the cam through a linear bearing. Thus, the cam moves back and forth while the shaft remains stationary. When the shaft is rotated around its axis, the cam surface is rotated around its axis and the stroke of the fuel pump changes. The change of the fuel injection portion, is set in motion stepper motor or manually.
Rice. 7. Fuel pump of a linear electric generator.
The drive of the fuel pump of a linear compressor is also a cam surface clamped between the plane of the pump piston and the plane of the pump casing, Fig. 8. The cam surface makes a reciprocating movement together with the synchronization gear shaft of the internal combustion engine, and moves apart the planes of the piston and pump at each stroke, while the pump piston moves relative to the pump cylinder and a portion of fuel is pushed to the fuel injection nozzle, at the beginning of the compression cycle ... When the linear compressor is running, there is no need to change the amount of fuel ejected. The operation of a linear compressor is meant only in conjunction with a receiver - an energy storage device that can smooth out peaks maximum load... Therefore, it is advisable to put the linear compressor motor into only two modes: optimal load mode and mode idle move... Switching between these two modes is done with solenoid valves, control system.
Rice. 8. Linear compressor fuel pump.
Starting system
The starting system of a linear motor is carried out, as in a conventional motor, with the help of an electric drive and an energy storage device. A conventional engine is started using a starter (electric drive) and a flywheel (energy storage). The linear motor is started using a linear electric compressor and a starting receiver, fig. nine.
Rice. 9. Starting system.
At start-up, the piston of the starting compressor, when energized, moves progressively due to the electromagnetic field of the winding, and then returns to its original state by a spring. After pumping the receiver to 8 ... 12 atmospheres, power is removed from the terminals of the starting compressor and the engine is ready to start. Start-up takes place by supplying compressed air to the inlet chambers of the linear motor. Air supply is carried out by means of solenoid valves, the operation of which is controlled by the control system.
Since the control system does not have information about the position of the engine connecting rods before starting, then by supplying high air pressure to the prestart chambers, for example, the outer cylinders, the pistons are guaranteed to move to their original state before starting the engine.
Then, high air pressure is supplied to the prestart chambers of the middle cylinders, thus, the cylinders are ventilated before starting.
After that, high air pressure is supplied again to the prestart chambers of the outer cylinders to start the engine. As soon as the operating cycle begins (the pressure sensor shows a high pressure in the combustion chamber corresponding to the operating cycle), the control system, using the solenoid valves, stops the air supply from the starting receiver.
Synchronization system
Synchronization of the connecting rod motor is carried out using a synchronizing gear and a pair of toothed racks, Fig. 10, attached to the moving part of the magnetic circuit of the generator or compressor pistons. The toothed gear is also the drive of the oil pump, with the help of which the units of the rubbing parts of the linear motor are forcibly lubricated.
Rice. 10. Synchronization of the generator rods.
Reducing the mass of the magnetic circuit and the circuit for switching on the windings of the generator.
The generator of the linear gasoline generator is a synchronous electric machine. In a conventional generator, the rotor rotates, and the mass of the moving part of the magnetic circuit is not critical. In a linear generator, the moving part of the magnetic circuit reciprocates together with the connecting rod of the internal combustion engine, and the high mass of the moving part of the magnetic circuit makes the operation of the generator impossible. It is necessary to find a way to reduce the mass of the moving part of the generator magnetic circuit.
Rice. 11. Generator.
To reduce the mass of the moving part of the magnetic circuit, it is necessary to reduce its geometric dimensions, respectively, the volume and mass will decrease, Fig. 11. But then the magnetic flux crosses only the winding in one pair of windows instead of five, it is equivalent that the magnetic flux crosses the conductor five times shorter, respectively , and the output voltage (power) will decrease 5 times.
To compensate for the decrease in generator voltage, it is necessary to add the number of turns in one window, so that the length of the conductor of the power winding becomes the same as in the original version of the generator, Fig. 11.
But so that a larger number of turns lie in a window with unchanged geometric dimensions, it is necessary to reduce transverse section conductor.
With a constant load and output voltage, the thermal load, for such a conductor, in this case will increase and become more optimal (the current remains the same, but the cross-section of the conductor has decreased by almost 5 times). This would be the case if the windings of the windows are connected in series, that is, when the load current flows through all the windings at the same time, as in a conventional generator. the winding in such a short period of time will not have time to overheat, since the thermal processes are inertial. That is, it is necessary to alternately connect to the load only that part of the generator winding (a pair of poles), which is crossed by the magnetic flux, the rest of the time it should cool down. Thus, the load is always connected in series with only one winding of the generator.
In this case, the effective value of the current flowing through the generator winding will not exceed the optimal value from the point of view of heating the conductor. Thus, it is possible to significantly, more than 10 times, reduce the mass of not only the moving part of the magnetic circuit of the generator, but also the mass of the stationary part of the magnetic circuit.
The windings are switched using electronic keys.
Semiconductor devices - thyristors (triacs) are used as keys for alternately connecting the generator windings to the load.
The linear generator is a deployed conventional generator, fig. eleven.
For example, at a frequency corresponding to 3000 cycles / min and a connecting rod stroke of 6 cm, each winding will heat up for 0.00083 seconds, with a current 12 times higher than the nominal one, the rest of the time - almost 0.01 seconds, this winding will be cooled. With a decrease in the operating frequency, the heating time will increase, but, accordingly, the current that flows through the winding and through the load will decrease.
A triac is a switch (it can close or open an electrical circuit). Closing and opening occurs automatically. During operation, as soon as the magnetic flux begins to cross the turns of the winding, then an induced electric voltage appears at the ends of the winding, this leads to the closure of the electrical circuit (opening of the triac). Then, when the magnetic flux crosses the turns of the next winding, then the voltage drop across the triac electrodes leads to the opening of the electrical circuit. Thus, at each moment of time, the load is switched on all the time, in series, with only one winding of the generator.
In fig. 12 shows an assembly drawing of a generator without a field winding.
Most of the parts of linear motors are formed by a surface of revolution, that is, they have a cylindrical shape. This makes it possible to manufacture them using the cheapest and most automated turning operations.
Rice. 12. Assembly drawing of the generator.
Mathematical model linear motor
The mathematical model of a linear generator is built on the basis of the law of conservation of energy and Newton's laws: at each moment of time, at t 0 and t 1, the equality of the forces acting on the piston must be ensured. After a short period of time, under the action of the resulting force, the piston will move a certain distance. In this short section, we assume that the piston was moving uniformly. The value of all forces will change according to the laws of physics and are calculated using the well-known formulas
All data is automatically entered into a table, for example, in Excel. After that t 0 values t 1 are assigned and the cycle is repeated. That is, we are performing a logarithm operation.
The mathematical model is a table, for example, in Excel, and an assembly drawing (sketch) of the generator. The sketch contains not linear dimensions, but the coordinates of the table cells in Excel. The corresponding assumed linear dimensions are entered into the table, and the program calculates and builds a graph of the piston movement in a virtual generator. That is, substituting the dimensions: the diameter of the piston, the volume of the pre-inlet chamber, the stroke of the pistons to the purge ports, etc., we will obtain graphs of the dependence of the distance traveled, the speed and acceleration of the piston movement on time. This makes it possible to virtually calculate hundreds of options and choose the most optimal one.
The shape of the winding wires of the generator.
The layer of wires of one window of a linear generator, unlike a conventional generator, lies in one spiral-twisted plane, so it is easier to wind the winding with wires not of a circular cross-section, but of a rectangular one, that is, the winding is a copper plate twisted in a spiral. This makes it possible to increase the fill factor of the window, as well as significantly increase the mechanical strength of the windings. It should be borne in mind that the speed of the connecting rod, and therefore the moving part of the magnetic circuit, is not the same. This means that the lines of magnetic induction cross the windings of different windows at different speeds. For full use winding wires, the number of turns of each window, must correspond to the speed of the magnetic flux near this window (the speed of the connecting rod). The number of turns of the windings of each window is selected taking into account the dependence of the speed of the connecting rod on the distance traveled by the connecting rod.
Also, for a more uniform voltage of the generated current, you can wind the winding of each window. copper plate different thicknesses. In the area where the speed of the connecting rod is not high, the winding is carried out with a thinner plate. A larger number of winding turns will fit into the window and, at a lower connecting rod speed in this section, the generator will produce a voltage commensurate with the current voltage in more "high-speed" sections, although the generated current will be much lower.
Application of a linear electric generator.
The main application of the described generator is an uninterruptible power supply at small enterprises, which allows the connected equipment to work for a long time in the event of a mains voltage failure, or when its parameters go beyond the permissible limits.
Electric generators can be used to provide electrical energy for industrial and household electrical equipment, in places where there are no electrical networks, as well as as power unit for vehicle (hybrid car), v quality mobile generator electrical energy.
For example, a generator of electrical energy in the form of a diplomat (suitcase, bag). The user takes with him to places where there are no electrical networks (construction site, camping, country house, etc.). devices. This is a common source of electrical energy, only much cheaper and lighter than analogs.
The use of linear motors makes it possible to create an inexpensive, easy to operate and control, light car.
Linear generator vehicle
A vehicle with a linear electric generator is two-seater light (250 kg) car, fig. 13.
Fig. 13. A car with a linear petrol generator.
When driving, you do not need to switch speeds (two pedals). Due to the fact that the generator can develop maximum power, even when "starting" from a place (in contrast to a conventional car), the acceleration characteristics, even with low traction engine powers, have better performance than similar characteristics of conventional cars. Power steering effect and ABS systems is achieved programmatically, since all the necessary "hardware" is already there (the drive to each wheel allows you to control the torque or braking moment of the wheel, for example, when you turn the steering wheel, the torque is redistributed between the right and left control wheels, and the wheels turn themselves, the driver only allows them to turn , i.e., effortless control). The block layout allows the car to be assembled at the customer's request (you can easily replace the generator with a more powerful one in a few minutes).
it regular car only much cheaper and lighter than analogues.
Features - ease of control, low cost, quick set of speed, power up to 12 kW, all-wheel drive (off-road vehicle).
A vehicle with the proposed generator, due to the specific shape of the generator, has a very low center of gravity, therefore it will have high driving stability.
Also, such a vehicle will have very high acceleration characteristics. The proposed vehicle can use the maximum power of the power unit over the entire speed range.
The distributed mass of the power unit does not load the car body, so it can be made cheap, lightweight and simple.
The traction engine of a vehicle, in which a linear electric generator is used as a power unit, must satisfy the following conditions:
The power windings of the motor must be directly, without a converter, connected to the terminals of the generator (to increase the efficiency of the electric transmission and reduce the cost of the current converter);
The speed of rotation of the output shaft of the electric motor should be regulated in a wide range, and should not depend on the frequency of operation of the electric generator;
The engine must have a high MTBF, that is, it must be reliable in operation (no collector);
The engine must be inexpensive (simple);
The motor must have a high torque at a low output speed;
The engine must be lightweight.
The circuit for switching on the windings of such a motor is shown in Fig. 14. By changing the polarity of the power supply to the rotor winding, we obtain the rotor torque.
Also, by changing the magnitude and polarity of the power supply of the rotor winding, slip rotation of the rotor relative to the stator magnetic field is introduced. By controlling the supply current of the rotor winding, slip control occurs, in the range from 0 ... 100%. The power supply of the rotor winding is approximately 5% of the motor power, therefore the current converter must be made not for the entire current of the traction motors, but only for their excitation current. The power of the current converter, for example, for an on-board electric generator of 12 kW, is only 600 W, and this power is divided into four channels (for each traction motor of the wheel its own channel), that is, the power of each channel of the converter is 150 W. Therefore, the low efficiency of the converter will not have a significant effect on the efficiency of the system. The converter can be built using low-power, low-cost semiconductor elements.
The current from the terminals of the generator is supplied without any transformations to the power windings of the traction motors. Only the excitation current is converted, so that it is always in antiphase with the current of the power windings. Since the excitation current is only 5 ... 6% of the total current consumed by the traction motor, the converter is needed for a power of 5 ... 6% of the total generator power, which will significantly reduce the price and weight of the converter and increase the efficiency of the system. In this case, the excitation current converter of traction motors needs to "know" in what position the motor shaft is in order to supply current to the excitation windings at each moment to create the maximum torque. The position sensor of the traction motor output shaft is an absolute encoder.
Fig. 14. Traction motor winding connection diagram.
The use of a linear electric generator as a power unit of a vehicle makes it possible to create a block-type vehicle. If necessary, large units and assemblies can be changed in a few minutes, fig. 15, and also use a body with the best airflow, since a low-power car has no power reserve to overcome air resistance due to imperfect aerodynamic shapes (due to a high drag coefficient).
Fig. 15. Possibility of block layout.
Linear compressor vehicle
The vehicle with a linear compressor is a two-seater lightweight (200 kg) vehicle, fig. 16. This is a simpler and cheaper analogue of a car with a linear generator, but with a lower transmission efficiency.
Fig. 16. Pneumatic drive of the car.
Fig. 17. Wheel drive control.
An incremental encoder is used as a wheel speed sensor. Incremental encoders have a pulse output, when turning through a certain angle, a voltage pulse is generated at the output. The electronic circuit of the sensor "counts" the number of pulses per unit of time, and writes this code into the output register. When the control system “feeds” the code (address) of this sensor, electronic circuit encoder, in a sequential form issues the code from the output register to the information conductor. The control system reads the sensor code (information about the speed of rotation of the wheel) and, according to a given algorithm, generates a code to control the stepper motor of the actuator.
Conclusion
The cost of a vehicle, for most people, is 20 ... 50 monthly earnings. People cannot afford to purchase new car for $ 8 ... 12 thousand, and there is no car on the market in the price range of $ 1 ... 2 thousand. The use of a linear electric generator or compressor as a power unit of a car makes it possible to create an easy-to-operate and inexpensive vehicle.
Modern technologies for the production of printed circuit boards, and the range of manufactured electronic products, allows you to make almost all electrical connections using two wires - power and information. That is, do not install the connection of each individual electrical device: sensors, actuators and signaling devices, but connect each device to a common power and common information wire. The control system, in turn, outputs the codes (addresses) of the devices, in a sequential code, to the information wire, after which it expects information about the state of the device, also in a sequential code, and along the same line. Based on these signals, the control system generates control codes for the actuators and signaling devices and transmits them to transfer the actuating or signaling devices to a new state (if necessary). Thus, during installation or repair, each device must be connected with two wires (these two wires are common to all on-board electrical appliances) and an electrical ground.
To reduce the cost, and, accordingly, the price of products for the consumer,
it is necessary to simplify installation and electrical connections onboard instruments... For example, in a traditional installation, to turn on the rear side light, it is necessary to close, with a switch, the electrical power circuit of the lighting device. The circuit consists of: a source of electrical energy, a connecting wire, a relatively powerful switch, an electrical load. Each element of the circuit, except for the power supply, requires individual installation, an inexpensive mechanical switch, has a low number of "on-off" cycles. With a large number of on-board electrical appliances, the cost of installation and connecting wires increases in proportion to the number of devices, the likelihood of error due to the human factor increases. For large-scale production easier management devices and reading information from sensors on one line, and not individually, for each device. For example, to turn on the taillight, in this case, you need to touch the touch sensor, the control circuit will generate a control code to turn on the taillight. The address of the tail light switch-on device and a signal to turn it on will be displayed on the information wire, after which the internal power circuit of the rear side light will be closed. That is, electrical circuits are formed in a complex way: automatically during the production of printed circuit boards (for example, when installing boards on SMD lines), and by electrical connection of all devices with two common wires and electrical "ground".
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The ability to switch to another type of fuel without stopping the engine.
Ignition control by pressure during compression of the working mixture.
In a conventional engine, two conditions must be met to supply electrical voltage (current) to the spark plug:
The first condition is determined by the kinematics of the crank mechanism - the piston must be at top dead center (ignoring the ignition timing);
The second condition is determined by the thermodynamic cycle - the pressure in the combustion chamber, before the operating cycle, must correspond to the fuel used.
It is very difficult to fulfill two conditions at the same time. When air or working mixture is compressed, the compressed gas leaks in the combustion chamber through the piston rings, etc. The slower the compression occurs (the slower the engine shaft rotates), the higher the leakage. In this case, the pressure in the combustion chamber, before the operating cycle, becomes less than the optimal one and the operating cycle occurs under non-optimal conditions. The efficiency of the engine drops. That is, it is possible to ensure a high efficiency of the engine only in a narrow range of speeds of rotation of the output shaft.
Therefore, for example, the efficiency of the engine on the bench is about 40%, and in real conditions, on a car, with different modes of movement, this value drops to 10 ... 12%.
In a linear engine there is no crank mechanism, so the first condition does not need to be fulfilled, it does not matter where the piston is located before the working cycle, only the gas pressure in the combustion chamber before the working cycle matters. Therefore, if the supply of electric voltage (current) to the spark plug is controlled not by the position of the piston, but by the pressure in the combustion chamber, then the working cycle (ignition) will always start at the optimum pressure, regardless of the engine operating frequency, Fig. 3.
Rice. 3. Ignition control using the pressure in the cylinder, in the "compression" cycle.
Thus, in any operating mode linear motor, we will have the maximum area of the loop of the thermodynamic Carnot cycle, respectively, and a high efficiency at different engine operating conditions.
Ignition control using the pressure in the combustion chamber also makes it possible to "painlessly" switch to other types of fuel. For example, when changing from a high-octane type of fuel to a low-octane type, in a linear engine, you only need to give a command to the ignition system so that the electric voltage (current) is supplied to the spark plug at a lower pressure. In a conventional engine, this would require changing the geometric dimensions of the piston or cylinder.
To implement ignition control by pressure in the cylinder, you can use
piezoelectric or capacitive pressure measurement method.
The pressure sensor is made in the form of a washer, which is placed under the nut of the cylinder head mounting stud, Fig. 3. The force of gas pressure in the compression chamber acts on the pressure sensor, which is located under the cylinder head fastening nut. And information about the pressure in the compression chamber is transmitted to the ignition timing control unit. When the pressure in the chamber corresponds to the ignition pressure of the given fuel, the ignition system supplies an electrical voltage (current) to the spark plug. With a sharp increase in pressure, which corresponds to the beginning of the operating cycle, the ignition system removes the electrical voltage (current) from the spark plug. If there is no increase in pressure after a specified time, which corresponds to the absence of the start of the working cycle, the ignition system gives a control signal to start the engine. Also, the output signal of the cylinder pressure sensor is used to determine the engine operating frequency and its diagnostics (determination of compression, etc.).
The compressive force is directly proportional to the pressure in the combustion chamber. After the pressure in each of the opposite cylinders becomes not less than the specified one (depending on the type of fuel used), the control system issues a command to ignite combustible mixture... If it is necessary to switch to another type of fuel, the value of the set (reference) pressure changes.
Also, the adjustment of the ignition timing of the combustible mixture can be carried out in automatic mode as in a conventional engine. A microphone is located on the cylinder - a knock sensor. The microphone converts the mechanical sound vibrations of the cylinder body into an electrical signal. A digital filter, from this set of the sum of the sinusoids of the electrical voltage, extracts the harmonic (sinusoid) corresponding to the detonation mode. When a signal appears at the output of the filter corresponding to the appearance of knocking in the engine, the control system reduces the value of the reference signal, which corresponds to the ignition pressure of the combustible mixture. In the absence of a signal corresponding to the detonation, the control system, after a while, increases the value of the reference signal, which corresponds to the ignition pressure of the combustible mixture, until the frequencies preceding the detonation appear. Again, when pre-detonation frequencies appear, the system lowers the reference signal, which corresponds to a decrease in ignition pressure, to detonation-free ignition. Thus, the ignition system adapts to the type of fuel used.
The principle of operation of a linear motor.
The principle of operation of a linear, like a conventional internal combustion engine, is based on the effect of thermal expansion of gases that occurs during the combustion of the fuel-air mixture and ensures the movement of the piston in the cylinder. The connecting rod transfers the linear reciprocating movement of the piston to a linear electric generator, or a piston compressor.
Linear generator, fig. 4, consists of two piston pairs operating in antiphase, which makes it possible to balance the engine. Each pair of pistons is connected by a connecting rod. The connecting rod is suspended on linear bearings and can oscillate freely, together with the pistons, in the generator housing. The pistons are placed in the cylinders of an internal combustion engine. The cylinders are purged through the purge ports, under the influence of a slight overpressure created in the pre-launch chamber. The moving part of the generator magnetic circuit is located on the connecting rod. The field winding creates a magnetic flux necessary to generate an electric current. With the reciprocating movement of the connecting rod, and with it a part of the magnetic circuit, the magnetic induction lines created by the excitation winding cross the stationary power winding of the generator, inducing an electric voltage and current in it (with a closed electric circuit).
Rice. 4. Linear gas generator.
Linear compressor fig. 5, consists of two piston pairs operating in antiphase, which makes it possible to balance the engine. Each pair of pistons is connected by a connecting rod. The connecting rod is suspended on linear bearings and can oscillate freely with the pistons in the housing. The pistons are placed in the cylinders of an internal combustion engine. The cylinders are purged through the purge ports, under the influence of a slight overpressure created in the pre-launch chamber. With the reciprocating movement of the connecting rod, and with it the compressor pistons, pressurized air is supplied to the compressor receiver.
Rice. 5. Linear compressor.
The working cycle in the engine is carried out in two strokes.
Linear motors have become widely recognized as a highly accurate and energy efficient alternative to conventional rotary-to-linear drives. How did this become possible?
So let's turn our attention to the ball screw, which in turn can be considered a high-precision system for converting rotational motion into translational motion. Typically, the efficiency of ball screws is about 90%. Taking into account the efficiency of the servo motor (75-80%), losses in the clutch or belt drive, in the gearbox (if used), it turns out that only about 55% of the power is spent directly on performing useful work. Thus, it is easy to guess why a linear motor, which directly transfers the translational motion to an object, is more efficient.
Usually the simplest explanation for its construction is the analogy with conventional engine rotational motion, which was cut along the generatrix and turned on the plane. In fact, this was exactly the design of the very first linear motors. The flat core linear motor was the first to enter the market and carve its niche as a powerful and efficient alternative to other drive systems. Despite the fact that, in general, their design turned out to be insufficiently effective due to significant eddy current losses, insufficient smoothness, etc., they still differed favorably from the point of view of efficiency. Although the above disadvantages adversely affected the high-precision "nature" of the linear motor.
The coreless U-type linear motor is designed to overcome the disadvantages of the classic flat linear motor. On the one hand, this allowed to solve a number of problems, such as eddy current losses in the core and insufficient smoothness of movement, but on the other hand, it introduced several new aspects that limit its use in areas requiring ultra-precision movements. This is a significant reduction in engine stiffness and even greater heat dissipation problems.
For the ultra-precision equipment market, linear motors were like a message from heaven, carrying the promise of infinitely precise positioning and high efficiency. However, the harsh reality showed itself when the heat generated due to the lack of efficiency of the structure in the windings and core was directly transferred to the working area. While the field of LD applications was expanding more and more, thermal phenomena accompanying significant heat release made positioning with submicron accuracy very difficult, not to say impossible.
To increase the efficiency and efficiency of a linear motor, it was necessary to return to its very constructive foundations, and through the maximum possible optimization of all their aspects to obtain the most energy-efficient drive system with the highest possible rigidity.
The fundamental interaction underlying the design of a linear motor is a manifestation of Ampere's Law - the presence of a force acting on a current-carrying conductor in a magnetic field.
The consequence of the equation for the Ampere force is that the maximum force developed by the motor is equal to the product of the current in the windings by the vector product of the vector of the magnetic induction of the field by the vector of the length of the wire in the windings. As a rule, to increase the efficiency of a linear motor, it is necessary to reduce the current in the windings (since the losses for heating the conductor are directly proportional to the square of the current in it). This can be done with a constant value of the output drive force is possible only with an increase in the other components included in the Ampere equation. This is exactly what the designers of the Cylindrical Linear Motor (CLM) did along with some manufacturers of ultra-precision equipment. In fact, a recent study at the University of Virginia (UVA) found that a CLD consumes 50% less energy to do the same job, at the same output, as a comparable U-shaped linear motor. To understand how such a significant increase in operational efficiency has been achieved, let's take a look at each component of the aforementioned Ampere equation.
Vector product B × L. Using, for example, the rule of the left hand, it is easy to understand that the optimal angle between the direction of the current in the conductor and the vector of magnetic induction is 90 ° for linear movement. Typically, in a linear motor, a current of 30-80% of the length of the windings flows at right angles to the field induction vector. The rest of the windings, in fact, perform an auxiliary function, while resistance losses occur in it and even forces opposite to the direction of movement may appear. The design of the CLD is such that 100% of the wire length in the windings is at an optimal angle of 90 °, and all the forces that arise are co-directed with the displacement vector.
Length of the current carrying conductor (L). Setting this parameter creates a kind of dilemma. Too long will lead to additional losses due to increased resistance. In the CLD, an optimal balance is observed between the length of the conductor and the losses due to the increase in resistance. For example, in a CLD tested at the University of Virginia, the length of the wire in the windings was 1.5 times longer than in its U-shaped counterpart.
Magnetic induction vector (B). Despite the fact that in most linear motors the magnetic flux is redirected using a metal core, a patented design solution is used in the CLD: the magnetic field strength naturally increases due to the repulsion of the magnetic fields of the same name.
The magnitude of the force that can be developed for a given structure of the magnetic field is a function of the flux density of the magnetic induction in the gap between the moving and stationary elements. Since the magnetic resistance of air is approximately 1000 times greater than that of steel and is directly proportional to the size of the gap, minimizing it will also reduce the magnetomotive force required to create a field of the required strength. The magnetomotive force, in turn, is directly proportional to the current in the windings, therefore, when its required value decreases, the current value can also be reduced, which in turn will allow reducing resistance losses.
As you can see, every aspect of the CLD has been designed to maximize its efficiency. But how useful is it from a practical point of view? Let's pay attention to two aspects: heat release and operating cost.
All linear motors heat up due to winding losses. The released heat must be dissipated somewhere. And the first side effect of heat release is the accompanying thermal expansion processes, for example, an element in which the windings are fixed. In addition, there is an additional heating of the guide wedges, lubricants, sensors located in the area of the drive. Over time, cyclic heating and cooling processes can negatively affect both the mechanical and electronic components of the system. Thermal expansion also leads to increased friction in guides and the like. In the same UVA study, it was found that the CLD transferred approximately 33% less heat to the plate mounted on it than its counterpart.
With less energy consumption, the cost of operating the system as a whole is also reduced. On average in the US, 1 kWh costs 12.17 cents. Thus, the average annual cost of operating a U-shaped linear motor will be $ 540.91, and a CLD $ 279.54. (At a price of 3.77 rubles per kWh, it turns out 16768.21 and 8665.74 rubles, respectively)
When choosing the implementation of a drive system, the list of options is really large, however, when developing a system designed for the needs of ultra-precision machine tool technology, the high efficiency of the CLD can provide significant advantages.
Dissertation abstract on this topic ""
As a manuscript
BAZHENOV VLADIMIR ARKADIEVICH
CYLINDRICAL LINEAR ASYNCHRONOUS MOTOR DRIVED BY HIGH-VOLTAGE CIRCUIT BREAKERS
Specialty 05.20.02 - electrical technologies and electrical equipment in agriculture
dissertation for the degree of candidate of technical sciences
Izhevsk 2012
The work was carried out in the federal state budgetary educational institution of higher professional education "Izhevsk State Agricultural Academy" (FGBOU V1YU Izhevsk State Agricultural Academy)
Scientific adviser: candidate of technical sciences, associate professor
1 at Vladykin Ivan Revovich
Official opponents: Viktor Vorobyov
Doctor of Technical Sciences, Professor
FGBOU VPO MGAU
them. V.P. Goryachkina
Bekmachev Alexander Egorovich Candidate of Technical Sciences, Project Manager of CJSC "Radiant-Elkom"
Lead organization:
Federal State Budgetary educational institution higher professional education "Chuvash State Agricultural Academy" (FGOU VPO Chuvash State Agricultural Academy)
The defense will take place on May 28, 2012 at 10 o'clock at a meeting of the Dissertation Council KM 220.030.02 at the Izhevsk State Agricultural Academy at the address: 426069,
Izhevsk, st. Student, 11, room 2.
The thesis can be found in the library of the Izhevsk State Agricultural Academy.
Posted on the site: tuyul ^ bba / gi
Scientific Secretary of the Dissertation Council
UFO. Litvinyuk
GENERAL DESCRIPTION OF WORK
on the integrated automation of rural electrical s ^ eGnanttT "
researches Sulimov M.I., Gusev B.C. marked with ™ ^
actions of relay protection and automation / rchGIV З0 ... 35% of cases
actuator state driveGHthan up to TsJTJ ™
the share of VM 10 ... 35 kV s, nv ", m" n mv "; Defects account for
N.M., Palyuga M ^ AaSTZ ^ rZZr ^ Tsy
of the
drive as a whole
■ PP-67 PP-67K
■ VMP-10P KRUN K-13
"VMPP-UP KRUN K-37
Figure I - Analysis of failures in electric drives VM 6 .. 35 kV VIA, they consume a lot of power and require cumbersome installation
failure of the shutdown mechanism, p.u.
00 "PP-67 PP-67
■ VMP-10P KRU | Outdoor furniture-13
■ VMPP-UP KRUN K-37 PE-11
- "","", and charger or a rectifier device-cumulative batar 3 ^ DD ° 0rMTs0M with a capacity of 100 kVA. By virtue of the
Swarms with "n ^^ prnvo" are widely used.
3aShYuNaRgbysh ^ "carry out an ™ and" from the merits of
dovdlyaVM. „„ _,., * Pivodov direct current: impossible-
Disadvantages of the electric thunderstorm, which includes the electromagnetism of the adjustment SK0R ° ^ DH ^ ^ el ^^. Apnpv, which increases the WITa> large ndu ^ and the input of the winding I from the polo.
time of switching on the switch ^ -¿ ^ "^ / ^^.„
a battery or - "P- ^ / ™ th area up to 70 m
Disadvantages of ^^^^^^^^
¡Yyyy- ^ 5 ^ -speed-u
T-D "Disadvantages of induction. Drive
B ^^ "ГГЖ cylindrical lines-The above-mentioned shortcomings *" structural special
"B, x asynchronous motors" Therefore, we propose to use them in
sts and weight and dimensions "O ^ 3 ^" "110 ^ 0 * e_ \ for oil switches-as a power element in the pr"
lei, which, according to Western-Ur ^ sko ^ companies in
the Udmurt Republic VMG-35 300 pieces.
operation "^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ant goal is?
"if the following analysis of existing drive designs was delivered
3 "theoretical and characteristics
ГрХГ ^ С - "- -" "6-35 *
based on TsLAD.
6. Carry out the technical and economic. ...
use of TsLAD for drives of oil switches 6 ... 35 kV.
The object of research is: cylindrical linear asynchronous motor(TsLAD) driving devices for switches of rural distribution networks 6 ... 35 kV.
Subject of research: the study of the traction characteristics of the CLAD when operating in oil circuit breakers 6 ... 35 kV.
Research methods. Theoretical research was carried out using the basic laws of geometry, trigonometry, mechanics, differential and integral calculus. Natural studies were carried out with the VMP-10 circuit breaker using technical and measuring tools. The experimental data were processed using the Microsoft Excel program. Scientific novelty of the work.
1. A new type of drive for oil switches has been proposed, which makes it possible to increase the reliability of their operation by 2.4 times.
2. A method for calculating the characteristics of the CLAD has been developed, which, in contrast to those proposed earlier, allows one to take into account the edge effects of the magnetic field distribution.
3. The main design parameters and operating modes of the drive for the VMP-10 circuit breaker are substantiated, which reduce the undersupply of electricity to consumers.
The practical value of the work is determined by the following main results:
1. The design of the VMP-10 circuit breaker drive has been proposed.
2. A method for calculating the parameters of a cylindrical linear induction motor has been developed.
3. A methodology and a program for calculating the drive have been developed, which make it possible to calculate the drives of circuit breakers of similar designs.
4. The parameters of the proposed drive for VMP-10 and the like have been determined.
5. A laboratory sample of the drive was developed and tested, which made it possible to reduce the losses of interruptions in power supply.
Implementation of research results. The work was carried out in accordance with the R&D plan of the FGBOU VPO CHIMESH, registration number№02900034856 "Development of a drive for high-voltage circuit breakers 6 ... 35 kV". The results of the work and recommendations were accepted and used in the software "Bashkirenergo" S-VES (an implementation certificate was received).
The work is based on the generalization of the results of research carried out independently and in collaboration with scientists from the FGBOU VPO Chelyabinsk State Agricultural University (Chelyabinsk), FGOU VPO Izhevsk State Agricultural Academy.
The following provisions have been brought up for defense:
1. Type of drive for oil circuit breakers based on TsLAD
2. Mathematical model for calculating the characteristics of the CLAD, as well as the traction
forces depending on the groove design.
a program for calculating a drive for circuit breakers of the VMG, VMP type with a voltage of 10 ... 35 kV. 4. Research results of the proposed design of the oil circuit breaker drive based on the CLAD.
Approbation of research results. The main provisions of the work were reported and discussed at the following scientific and practical conferences: XXXIII scientific conference dedicated to the 50th anniversary of the Institute, Sverdlovsk (1990); international scientific-practical conference "Problems of energy development in the context of industrial transformations" (Izhevsk, FGBOU V PO Izhevsk State Agricultural Academy 2003); Regional scientific and methodological conference (Izhevsk, FGBOU VPO Izhevsk State Agricultural Academy, 2004); Topical problems of mechanization Agriculture: materials of the jubilee scientific and practical conference "Higher agroengineering education in Udmurtia - 50 years". (Izhevsk, 2005), at the annual scientific and technical conferences of teachers and employees of the Izhevsk State Agricultural Academy.
Publications on the topic of the thesis. The results of theoretical and experimental studies are reflected in 8 printed works, including: in one article published in a journal recommended by the Higher Attestation Commission, two deposited reports.
Structure and scope of work. The dissertation consists of an introduction, five chapters, general conclusions and annexes, set out on 167 pages of the main text, contains 82 figures, 23 tables and lists of used sources from 105 titles and 4 annexes.
In the introduction, the relevance of the work is substantiated, the state of the issue, the purpose and objectives of the research are considered, the main provisions for the defense are formulated.
The first chapter analyzes the designs of the circuit breaker drives.
Installed:
The principal advantage of combining the drive with the CLAD;
The need for further research;
Goals and objectives of the thesis.
In the second chapter, methods for calculating the CLAD are considered.
Based on the analysis of the propagation of the magnetic field, a three-dimensional model was selected.
The winding of the CLAD generally consists of separate coils connected in series in a three-phase circuit.
We consider a CLAD with a single-layer winding and a secondary element in the gap that is symmetrical with respect to the inductor core.
The following assumptions are accepted: 1. The current of the winding, laid at a length of 2рm, is concentrated in infinitely thin current layers located on the ferromagnetic surfaces of the inductor and creates a purely sinusoidal traveling wave. The amplitude is related to the known relationship with the linear current density and current load
creates a pure sinusoidal traveling wave. The amplitude is related to the known relationship with the linear current density and current load
to "" "d." "*. (1)
t - pole; w is the number of phases; W is the number of turns in a phase; I is the effective value of the current; P is the number of pole pairs; J is the current density;
Ko6 | - winding fundamental harmonic distortion.
2. The primary field in the area of the frontal parts is approximated by the exponential function
/ (") = 0.83 exp ~~~ (2)
The reliability of such an approximation to the real picture of the field is confirmed by earlier studies, as well as experiments on the LIM model. In this case, it is possible to replace L-2 s.
3. The origin of the fixed coordinate system x, y, z is located at the beginning of the winding part of the incident edge of the inductor (Fig. 2).
With the accepted formulation of the problem, the researcher the windings can be represented as a double Fourier series:
where, A is the linear current load of the inductor; Cob - winding coefficient; L is the width of the reactive bus; C is the total length of the inductor; a - shear angle;
z = 0.5L - a - zone of induction change; n is the order of the harmonic along the transverse axis; v- order of harmonics along the longitudinal basis;
We find the solution for the vector magnetic potential of currents A In the region of the air gap Ar satisfies the following equations:
divAs = 0. J (4)
For EE equations A 2, the equations have the form:
DA2. = ГгМ 2 СИУ Т2 = 0.
The solution of equations (4) and (5) is carried out by the method of separation of variables. To simplify the problem, we give only the expression for the normal component of the induction in the gap:
hell [KY<л
y 2a V 1st<ЬК0.51.
_¿1- 2s -1 -1 "
Figure 2 - Calculated mathematical model of LIM without taking into account the distribution of the winding
KP2. SOB --- AH
X (STRY + C ^ LYY) exp y
The total electromagnetic power S3M, transmitted from the primary part to the s "orTVE, Xeg can be found as the flux of the normal 8, a component of the Poyting vector through the surface y - 5
= / / RWL =
"- - \ shXS + C2sILd \ 2
^ ГрЛс ^ ГвВэГ "" "С0Staying" У ™ "*" "" mechanical power
Р ™ with "ЗР ™" ШЯ С ° CUTTING "LEARNS THE FLOW"
C \ is a complex of conjugations with C2.
"Z-or,", g ".msha" "fret" ". ..Z
II "in e., Brcbc
^ И О Л V о_ £ V у
- "" \ shXS + C. cbaz? "
"" - ^ / H ^ n ^ m- ^ rI
l "\ shXS + C2c1gL5 ^
on nn ^ ech ^^ A ^ eToT ^ ^ "b = 2c> ™ -rmo" uk coordinate A-U In addition to Г Г ^ Г in two-dimensional, according to
chie steel ^ torus ^ to ^^^ i e ^ great things ^ G ^ part ourg "
2) Mechanical power
Electromagnetic power £,., "1 = p / s" + .y, / C1 "1"
according to the expression, formula (7) was calculated according to
4) Copper loss of inductor
P, r1 = ШI1 Гф ^
where gf is the active resistance of the phase winding;
5) K p d. Without taking into account losses in the steel of the core
„P.-i” (12) P, P „(5> + L, ..
6) Power factor
p m! \ zy + rf)
where, 2 = + x1 is the modulus of the impedance of the series
equivalent circuits (Figure 2).
x1 = x „+ xa1 O4)
v -Yaz- g (15)
x = x + x + x + Xa is the leakage inductive reactance of the primary ob-p a * h
М ° ™ Thus, an algorithm for calculating the static characteristics of a LIM with a short-circuited secondary element has been obtained, which makes it possible to take into account the properties of the active parts of the structure at each tooth division.
The developed mathematical model allows:. Apply a mathematical apparatus for calculating a cylindrical lens-type induction motor, its static characteristics on the basis of power substitution circuits for electrical primary and secondary and magnetically "
To assess the influence of various parameters and designs of the secondary element on the traction and energy characteristics of a cylindrical linear induction motor. ... The calculation results make it possible to determine, in a first approximation, the optimal basic technical and economic data in the design of cylindrical linear induction motors.
The third chapter "Computational and theoretical studies" presents the results of numerical calculations of the influence of various parameters and geometrical ones on the energy and thrust indicators of the CLAD using the mathematical model described earlier.
The TsLAD inductor consists of separate washers located in a ferromagnetic cylinder. The geometric dimensions of the inductor washers taken in the calculation are shown in Fig. 3. The number of washers and the length of the ferromagnetic cylinder is the number of poles and the number of slots per pole and the phase of the winding of the inductor 1 ^ zw (the parameters of the inductor (geometry of the toothed layer, the number of poles, pole division, length and width) of the secondary structure - type windings, electrical conductivity C2 - Ang L, a
See also the parameters of the reverse magnetic circuit. In this case, the results of the study are presented in the form of graphs.
Figure 3 - Inductor device 1-Secondary element; 2-nut; Z-sealing washer; 4- coil; 5-engine housing; 6-winding, 7-washer.
For the developed circuit breaker drive, the following are uniquely defined:
1 Mode of operation, which can be characterized as "start". Time "of work - less than a second (t. = 0.07s), repeated starts can be, but even in
In this case, the total operating time does not exceed a second. Consequently, electromagnetic loads are a linear current load, the current density in the windings can be taken significantly higher than those taken for j steady-state modes of electrical machines: A = (25 ... 50) 10 A / m, J (4 ... /) A / mm2. Therefore, the thermal state of the machine can be disregarded.
3. Required pulling force F „> 1500 N. In this case, the change in force during operation should be minimal.
4. Severe size restrictions: length Ls. 400 mm; the outer diameter of the stator is D = 40 ... 100 mm.
5 Energy values (l, coscp) are irrelevant.
Thus, the research task can be formulated as follows: for given dimensions, determine the electromagnetic loads the value of the LIM design parameters,
available tractive effort in the range of 0.3
Based on the formed research task, the main indicator of the LIM is the tractive effort in the slip interval 0.3
Thus, the thrust force of the LAD appears to be a functional dependence.
Fx = f (2p, r, & d2, y2, Yi, Ms> H< Wk, A, a) U<>>
some tameters pr-t -ko and t = 400/4 = 100 - * 66.6 mmGh
tel "SPYAVGICHE" IeM NUMBER P ° LYUS0V "U" 0806 Pulling force decreases significantly - 5
TRACTION ° FORCE Associated with a decrease in pole division t and magnetic induction in air and division t
is 2p = 4 (Fig. 4). ° AIR CLEARANCE Therefore, the optimum
OD 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 9
Slide B, oh
Figure 4 - Traction characteristic of the CLAD „depending on the number of pods
3000 2500 2000 1500 1000 500 0 ■
1.5 | at 2.0L<
0 0.10.20.30.40.50.60.70.80.9 1 ^ slip B, oe
RISU5YUK5, azo.
ra (6 = 1.5mm and 5 = 2.0mm)
conductivity y2, y3 and magnetic permeability c3 HE.
The change in the electrical conductivity of the steel cylinder ”(Fig. 6) has an insignificant value of up to 5% on the traction force of the CLAD.
0 0,10,23,30,40,50,60,70,83,91
Slide 8th.
Figure 6. Traction characteristic of the CLAD at various values of the electrical conductivity of the steel cylinder
The change in the magnetic permeability μ3 of the steel cylinder (Fig. 7) does not bring significant changes in the traction force Px = DB). With a working slip of 8 = 0.3, the traction characteristics are the same. Starting tractive effort varies within 3 ... 4%. Consequently, taking into account the insignificant influence of knots and Mz on the traction force of the CLAD, the steel cylinder can be made of soft magnetic steel.
0 0 1 0 2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Glide
Figure 7. The thrust characteristic of the CDAD at various values of the magnetic permeability (Cz = 1000c and Cz = 500cr) of a steel cylinder
From the analysis of the graphical dependencies (Fig. 5, Fig. 6, Fig. 7), the conclusion follows: changes in the conductivity of the steel cylinder and magnetic permeability, limitation of the non-magnetic gap, it is impossible to achieve a constant traction force 1 "X due to their small effect.
y = 1.2-10 "S / m
y = 3 10 "S / m
О 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Slip E, oe
Figure 8. The traction characteristic of the CLAD at various values of the electrical conductivity of the SE
The parameter with which it is possible to achieve the constancy of the tractive effort = / (2p, r,<$ й2 ,у2, уз, цз, Я, А, а) ЦЛАД, является удельная электропроводимость у2 вторичного элемента. На рисунке 8 указаны оптимальные крайние варианты проводимостей. Эксперименты, проведенные на экспериментальной установке, позволили определить наиболее подходящую удельную проводимость в пределах у=0,8-10"...1,2-ю"См/м.
Figures 9 ... 11 show the dependences Г, I, т), oo $<р = /(я) при различных значениях числа витков в катушке обмотки индуктора ЦЛАД с экранированным вторичным э л е м е нто в (с/,=1 мм; 5=1 мм).
Lg az o * ~ 05 Ob d5 To
Figure 9. Dependence 1 = Г (8) for different values of the number of turns in the coil
Figure 10. Dependency eos Drawing! I Dependence t] = f (S) The graphical dependences of energy indicators on the number of turns in porridges coincide. This suggests that a change in the number of turns in the coil does not lead to a significant change in these indicators. This is the reason for the lack of attention to them. The increase in tractive effort (Fig. 12) with a decrease in the number of turns in the coil is explained by the fact. that the cross-section of the wire increases with constant values of the geometric dimensions and the filling factor of the inductor groove with copper and a slight change in the value of the current density. The motor in the drives of the switches runs in the starting mode for less than a second. Therefore, to drive mechanisms with a large starting traction force and a short-term operating mode, it is more efficient to use a CLAD with a small number of turns and a large wire section of the coil of the inductor winding. mol / "4a? /? (/," ■ SH0O 8oo boa íoo 2 os ■ O o / O.Z oi 05 O 07 os ¿J? That Figure 12. The traction characteristic of the CLAD at different values of the number of turns era of the mountain coil However, with frequent switching on of such mechanisms, it is necessary to have a heating margin for the engine. Thus, based on the results of a numerical experiment using the above-described calculation method, it is possible with a sufficient degree of accuracy to determine the tendency of changes in electrical and traction indicators for various variables of the CLAD. The main indicator for the constancy of the tractive effort is the electrical conductivity of the coating of the secondary element у2 By changing it within the range у = 0.8-10 ... 1.2-10 S / m, it is possible to obtain the necessary traction characteristic. Consequently, for the constancy of the thrust of the MLAD, it is sufficient to set the constant values 2p, m, 8, y), Tsz, ! ], = / (K y2, \ Vk) (17) where K = / (2p, m, 8, A2, y, Ts " In the fourth chapter, a technique for conducting an experiment of the investigated method of driving a circuit breaker is described. Experimental studies of the drive characteristics were carried out on a VMP-10 high-voltage circuit breaker (Fig. 13) Figure 13 Experimental setup. Also in this chapter, the inertial resistance of the circuit breaker is determined, which is carried out using the technique presented in the graphical analytical method, using the kinematic circuit of the circuit breaker. The characteristics of elastic elements are determined. At the same time, several elastic elements are included in the design of the oil circuit breaker, which resist the closing of the circuit breaker and allow accumulating energy to open the circuit breaker: 1) Springs acceleration GPu ", 2) Spring cut-off G on ", 31 Elastic forces created by contact springs Pk. - No. 1, 2012 S. 2-3. - Access mode: http: // w \ v \ v.ivdon.ru. Other editions: 2. Pyastolov, A.A. Development of a drive for high-voltage switches 6 ... 35 kV. "/ AA Pyastolov, IN Ramazanov, RF Yunusov, VA Bazhenov // Report on research work (x. No. GR 018600223428 liv. No. 02900034856.-Chelyabinsk: CHIMESH. 1990. - S. 89-90. 3. Yunusov, R.F. Development of a linear electric drive for agricultural purposes. /R.F. Yunusov, I.N. Ramazanov, V.V. Ivanitskaya, V.A. Bazhenov // XXXIII scientific conference. Abstracts of reports. - Sverdlovsk, 1990, pp. 32-33. 4. Pyastolov, A.A. High voltage oil circuit breaker drive. / Yunusov R.F., Ramazanov I.N., Bazhenov V.A. // Fact sheet No. 91-2. -CSTI, Chelyabinsk, 1991.S. 3-4. 5. Pyastolov, A.A. Cylindrical linear induction motor. / Yunusov R.F., Ramazanov I.N., Bazhenov V.A. // Fact sheet No. 91-3. -CSTI, Chelyabinsk, 1991. p. 3-4. 6. Bazhenov, V.A. Selection of an accumulating element for the VMP-10 circuit breaker. Actual problems of agricultural mechanization: materials of the jubilee scientific and practical conference "Higher agroengineering education in Udmurtia - 50 years." / Izhevsk, 2005.S. 23-25. 7. Bazhenov, V.A. Development of an economical drive for an oil circuit breaker. Regional scientific and methodological conference Izhevsk: FGOU VPO Izhevsk State Agricultural Academy, Izhevsk, 2004. S. 12-14. 8. Bazhenov, V.A. Improvement of the VMP-10 oil circuit breaker drive. Problems of energy development in the context of industrial transformations: Proceedings of the international scientific and practical conference dedicated to the 25th anniversary of the Faculty of Electrification and Automation of Agriculture and the Department of Electrotechnology of Agricultural Production. Izhevsk 2003, pp. 249-250. dissertation for the degree of candidate technical spider Rented in set_2012 Signed for printing on April 24, 2012. Offset paper Font Times New Roman Format 60x84 / 16. Volume I printed sheet. Circulation 100 copies. Order No. 4187. Publishing house of FGBOU BIIO Izhevsk State Agricultural Academy Izhevsk, st. Student. eleven FEDERAL STATE BUDGETARY EDUCATIONAL INSTITUTION OF HIGHER PROFESSIONAL EDUCATION "IZHEVSK STATE AGRICULTURAL ACADEMY" As a manuscript Vladimir Bazhenov CYLINDRICAL LINEAR ASYNCHRONOUS MOTOR DRIVED BY HIGH-VOLTAGE CIRCUIT BREAKERS Specialty 05.20.02 Electrotechnology and electrical equipment in agriculture DISSERTATION for the degree of candidate of technical sciences Scientific adviser: candidate of technical sciences, Vladykin Ivan Revovich Izhevsk - 2012 At various stages of research, the work was carried out under the guidance of Doctor of Technical Sciences, Professor, Head. Department of Electrical Machines, Chelyabinsk Institute of Mechanization and Electrification of Agriculture A.A. Pyastolova (chapter 1, 4, 5) and doctor of technical sciences, professor, head. Department of "Electric drive and electrical machines" of the St. Petersburg State Agrarian University A.P. Epifanova (Chapter 2, 3), The author expresses his sincere gratitude. INTRODUCTION ................................................. .................................................. ....................................5 1 ANALYSIS OF OIL SWITCH DRIVES AND THEIR CHARACTERISTICS .......................................... .................................................. ........................................... 7 1.1 Design and principle of operation of switches ............................................ ......eleven 1.2 Classification of actuators ............................................... .....................................fourteen 1.3 Main drive elements .............................................. ................................19 1.4 General design requirements for drives ............................................ ..22 1.5 Electromagnetic actuators ............................................... ................................ 26 1.5.1 Design of electromagnetic drives ............................................ ....... 28 1.5.2 AC solenoid actuator .......................................... .42 1.5.3 Drive based on a flat LIM .......................................... .......................... 45 1.5.4 Circuit breaker drive based on a rotating induction motor ... .................................................. ...................................... 48 1.5.5 Drive based on cylindrical linear asynchronous engine ................................................. .................................................. .......................50 CHAPTER CONCLUSIONS AND OBJECTIVES OF THE WORK ............................................ .............................. 52 2 CALCULATION OF THE CHARACTERISTICS OF LINEAR ASYNCHRONOUS MOTOR-GAGELS .......................................... .................................................. ............................................ 55 2.1 Analysis of methods for calculating the characteristics of LIM ............................................ ....... 55 2.2 Method based on one-dimensional theory ............................................. ........................... 56 2.3 Methodology based on two-dimensional theory ............................................ ............... 58 2.4 Technique based on a three-dimensional model ............................................ ............... 59 2.5 Mathematical model of a cylindrical induction motor on based on the equivalent circuit ............................................... ................................................. 65 CHAPTER CONCLUSIONS ............................................... .................................................. ................. 94 3 CALCULATION AND THEORETICAL RESEARCH ............................................. ...... 95 3.1 General provisions and tasks to be solved (problem statement) ........................... 95 3.2. Investigated indicators and parameters ............................................ ....................... 96 CHAPTER CONCLUSIONS ............................................... .................................................. ............. 105 4 EXPERIMENTAL STUDIES ............................................... ........... 106 4.1 Determination of the inertial resistance of the VM-drive system .................... 106 4.2 Determination of the characteristics of elastic elements ............................................ 110 4.3 Determination of electrodynamic characteristics ....................................... 114 4.4 Determination of aerodynamic air resistance and hydraulic insulating oil ВМ .............................................. ................. 117 CHAPTER CONCLUSIONS ............................................... .................................................. .............. 121 5 TECHNICAL AND ECONOMIC INDICATORS .............................................. ........ 122 CHAPTER CONCLUSIONS ............................................... .................................................. .............. 124 GENERAL CONCLUSIONS AND RESULTS OF STUDIES ........................................ 125 LITERATURE................................................. .................................................. .......................... 126 APPENDIX A ................................................ .................................................. ................... 137 APPENDIX B CALCULATION OF RELIABILITY INDICATORS VM6 ... 35KV ... 139 APPENDIX B REFERENCE ABOUT THE RESEARCH OF THE OBJECT OF DEVELOPMENT ................... 142 I Patent Documentation ............................................... ........................................ 142 II Scientific and technical literature and technical documentation ........................ 143 III Technical characteristics of cylindrical linear induction motor ........................................... .................................................. ........................... 144 IV Analysis of operational reliability of drives VM-6 .. .35 kV ...................... 145 V Design features of the main types of drives VM-6 ... 35 kV ........ 150 APPENDIX D ................................................ .................................................. .................... 156 An example of a specific execution of the drive .............................................. .................. 156 high-voltage switch ................................................ ................................... 156 Calculation of the power consumed by the inertial drive ...................................... 162 during the operation of turning on the VM .............................................. ........................................ 162 Index of basic symbols and abbreviations ............................................. ......... 165 INTRODUCTION With the transfer of agricultural production to an industrial basis, the requirements for the level of reliability of power supply are significantly increased. The target comprehensive program for increasing the reliability of power supply to agricultural consumers / CKP PN / provides for the widespread introduction of automation equipment for rural distribution networks of 0.4 ... 35 kV, as one of the most effective ways to achieve this goal. The program includes, in particular, equipping distribution networks with modern switching equipment and drive devices for them. Along with this, it is assumed widespread use, especially at the first stage, of the primary switching equipment in operation. The most widespread in rural networks are oil circuit breakers (VM) with spring and spring-load drives. However, it is known from operating experience that VM drives are one of the least reliable elements of switchgear. This reduces the effectiveness of the integrated automation of rural electrical networks. For example, in it is noted that 30 ... 35% of cases of relay protection and automation / RPA / are not implemented due to the unsatisfactory state of the drives. Moreover, up to 85% of defects are accounted for by VM 10 ... 35 kV with spring-load drives. According to the work data, 59.3% of failures of automatic reclosing / AR / based on spring drives occur due to auxiliary contacts of the drive and circuit breaker, 28.9% due to mechanisms for switching on the drive and holding it in the closed position. The unsatisfactory condition and the need for modernization and development of reliable drives are noted in the works. There is a positive experience of using more reliable electromagnetic DC drives for 10 kV VM at step-down substations for agricultural purposes. However, due to a number of features, these drives have not found wide application [53]. The purpose of this stage of research is to choose the direction of research. In the process of work, the following tasks were solved: Determination of reliability indicators of the main types of drives VM-6 .. .35 kV and their functional units; Analysis of the design features of various types of drives VM-6 ... 35 kV; Justification and selection of a constructive solution for the VM 6 ... 35 kV drive and research directions. 1 ANALYSIS OF OIL SWITCH ACTUATORS AND THEIR CHARACTERISTICS The operation of the drive for oil circuit breakers 6-10 kV largely depends on the design perfection. Design features are determined by the requirements for them: The power consumed by the drive during the operation of turning on the VM must be limited, because power is supplied from low-power auxiliary transformers. This requirement is especially important for step-down substations for agricultural power supply. The oil circuit breaker drive must ensure a sufficient switching speed, Remote and local control, Normal operation at permissible levels of change in operating voltages, etc. Based on these requirements, the main mechanisms of the drives are made in the form of mechanical converters with a different number of stages (stages) of amplification, which, in the process of turning off and on, consume little power to control a large flow of energy consumed by the switch. In known drives, amplification cascades are structurally performed in the form of locking devices (ZUO, ZUV) with latches, reducing mechanisms (RM) with multi-link breaking levers, as well as mechanical amplifiers (MU) using the energy of a raised load or a compressed spring. Figures 2 and 3 (Appendix B) show simplified diagrams of drives for oil switches of various types. The arrows and numbers above them show the direction and sequence of interaction of mechanisms in the process of work. The main switching devices at substations are oil and oil-free switches, disconnectors, fuses with voltage up to 1000 V and above, circuit breakers, circuit breakers. In electrical networks of low power with a voltage of 6-10 kV, the simplest switching devices are installed - load switches. In switchgears 6 ... 10 kV, in withdrawable switchgear, low-oil pendant switches with built-in spring or electromagnetic drives (VMPP, VMPE) are often used: Rated currents of these switches: 630 A, 1000 A, 1600 A, 3200 A. Breaking current 20 and 31.5 kA. This range of designs makes it possible to use VMP circuit breakers both in medium-power electrical installations and on large input lines and on the side of secondary circuits of relatively large transformers. The version for a current of 31.5 kA allows the use of compact VMP circuit breakers in powerful networks of 6 ... 10 kV without reacting and thereby reduce voltage fluctuations and deviations in these networks. Low-oil pot type switches VMG-10 with spring and electromagnetic drives are manufactured for rated currents of 630 and 1000 A and short-circuit breaking current of 20 kA. They are built into stationary cameras of the KSO-272 series and are mainly used in medium-power electrical installations. There are also low-oil circuit breakers of the VMM-10 type of low power with built-in spring drives for a rated current of 400 A and a rated breaking current of 10 kA. In a wide range of designs and parameters, electromagnetic switches of the following types are manufactured: VEM-6 with built-in electromagnetic drives for a voltage of 6 kV, rated currents 2000 and 3200 A, rated breaking current 38.5 and 40 kA; VEM-10 with a built-in electromagnetic drive, for a voltage of 10 kV, rated currents 1000 and 1250, rated breaking current 12.5 and 20 kA; VE-10 with built-in spring drives, for voltage 10 kV, rated currents 1250, 1600, 2500, 3000 A. Rated breaking currents 20 and 31.5 kA. Electromagnetic switches in their parameters correspond to low-oil switches VMP and have the same field of application. They are suitable for frequent switching operations. The switching capacity of the switches depends on the type of drive, its design and reliability. At substations of industrial enterprises, spring and electromagnetic drives built into the circuit breaker are mainly used. Electromagnetic drives are used in critical installations: When powering electrical receivers of the first and second categories with frequent switch operations; Particularly critical electrical installations of the first category, regardless of the frequency of operations; With a rechargeable battery. For substations of industrial enterprises, complete large-block devices are used: switchgear, KSO, KTP of various power, voltage and purpose. Complete devices with all devices, measuring instruments and auxiliary devices are manufactured, assembled and tested at the factory or in a workshop, and assembled are delivered to the installation site. This gives a great economic effect, as it speeds up and reduces the cost of construction and installation and allows you to work by industrial methods. Complete switchgears have two fundamentally different designs: withdrawable (switchgear series) and stationary (series KSO, KRUN, etc.). Devices of both types are equally successful in solving the problems of electrical installation and maintenance work. Withdrawable switchgears are more convenient, reliable and safe to operate. This is achieved by protecting all live parts and contact connections with reliable insulation, as well as the possibility of quick replacement of the circuit breaker by rolling out and servicing in the workshop. The arrangement of the circuit breaker drive is such that its external inspection can be carried out both when the circuit breaker is on and off, without rolling out the latter. Plants produce unified series of withdrawable switchgear for indoor installation for voltages up to 10 kV, the main technical parameters of which are given in Table 1. Table 1.1- Basic parameters of switchgear for voltage 3-10 kV for indoor installation Series Rated voltage, in kV Rated current, in A Type of oil circuit breaker Drive type KRU2-10-20UZ 3.6, 10 630 1000 1600 2000 2500 3200 Low oil pot VMP-Yuld PE-11 PP67 PP70 KR-10-31, 5UZ 6.10 630 1000 1600 3200 Low oil pot KR-10D10UZ 10 1000 2000 4000 5000 Low oil pot KE-10-20UZ 10 630 1000 1600 2000 3200 Electromagnetic KE-10-31, 5UZ 10 630 1000 Electromagnetic 1.1 Design and principle of operation of switches Switches of the VMG-10-20 type are three-pole high-voltage switches with a small volume of arc-extinguishing liquid (transformer oil). The switch is designed for switching high-voltage AC circuits with a voltage of 10 kV in the normal operating mode of the installation, as well as for automatic shutdown of these circuits in case of short-circuit currents and overloads that occur during abnormal and emergency operating modes of the installation. The principle of operation of the circuit breaker is based on extinguishing the electric arc that occurs when the contacts are opened by the flow of the gas-oil mixture, which is formed as a result of the intensive decomposition of the transformer oil under the action of the high temperature of the arc. This flow receives a certain direction in a special arc-extinguishing device located in the arc burning zone. The circuit breaker is controlled by drives. In this case, the operative switching on is carried out at the expense of the drive energy, and the disconnection is made at the expense of the energy of the opening springs of the circuit breaker itself. The circuit breaker design is shown in Fig. 1.1. Three poles of the switch are mounted on a common welded frame 3, which is the base of the switch and has holes for fastening the switch. On the front side of the frame, there are six porcelain insulators 2 (two per pole) with internal elastic mechanical fastening. A pole of the switch 1 is suspended on each pair of insulators. The operating mechanism of the circuit breaker (Fig. 9) consists of a shaft 6 with levers 5 welded to it 5. To the extreme levers 5 are connected opening springs 1, to the middle - a buffer spring 2. At the opposite ends of the levers, insulating levers are mechanically fixed, which are connected to current-carrying contact rods 9 with the help cabbage soup earrings 7 and serve to transfer movement from the switch shaft to the contact rod. installations (type VMP-10) - general view A pair of two-armed levers 4 with rollers at the ends are welded between the extreme and middle levers on the switch shaft. These levers serve to limit the closed and closed positions of the circuit breaker. When turned on, one of the rollers approaches the bolt 8, when turned off, the second roller moves the oil buffer rod 3; a more detailed structure of which is shown in Fig. 1. 2. Depending on the kinematics of the cubicle, the switch permits a central or lateral drive connection. With the middle connection of the drive, lever 13 is used (Fig. 1.1); for lateral connection, lever 12 is additionally installed on the switch shaft (Fig. 1.1). Figure 1.2 - Switch pole The main part of the pole of the circuit breaker (Fig. 1.2) is cylinder 1. For circuit breakers with a rated current of 1000A, these cylinders are made of brass. Cylinders of switches for rated current 63ОА are made of steel and have a longitudinal non-magnetic seam. Two brackets are welded to each cylinder for attaching it to the support insulators, and a casing 10 with an oil filler plug 11 and an oil indicator 15. The casing serves as a supplement The invention relates to electrical engineering and can be used in rodless pumping and borehole installations for the production of formation fluids from medium and large depths, mainly in oil production. The cylindrical linear induction motor contains a cylindrical inductor with a multiphase winding made with the possibility of axial movement and mounted inside a steel secondary element. The secondary steel element is a motor housing, the inner surface of which is coated with a highly conductive copper layer. The cylindrical inductor is made of several modules selected from the phase coils and interconnected by flexible coupling. The number of inductor modules is a multiple of the number of winding phases. When moving from one module to another, the phase coils are stacked with alternate changes in the location of the individual phases. With a motor diameter of 117 mm, an inductor length of 1400 mm, an inductor current frequency of 16 Hz, the electric motor develops a force of up to 1000 N and a power of 1.2 kW with natural cooling and up to 1800 N with oil cooling. The technical result consists in increasing the tractive effort and power per unit length of the engine under conditions of limitation on the diameter of the body. 4 ill. SUBSTANCE: invention relates to structures of submersible cylindrical linear asynchronous motors (CLAD) used in rodless pumping and borehole installations for production of formation fluids from medium and great depths, mainly in oil production. The most common way to recover oil is to lift oil from wells using sucker rod pumps driven by pumping units. In addition to the obvious disadvantages inherent in such installations (large dimensions and weight of pumping units and rods; wear of tubing and rods), a significant disadvantage is also the small possibilities for regulating the speed of movement of the plunger, and hence the performance of sucker-rod pumping units, the impossibility of working in deviated wells. The ability to regulate these characteristics would take into account the natural changes in the well flow rate during its operation and reduce the number of standard sizes of pumping units used for various wells. Known technical solutions for the creation of rodless downhole pumping units. One of them is the use of deep plunger pumps driven by linear asynchronous motors. The known design of the CLAD, mounted in the tubing above the plunger pump (Izhelya GI and others "Linear induction motors", Kiev, Technics, 1975, p. 135) / 1 /. The known engine has a housing, a stationary inductor placed in it and a movable secondary element located inside the inductor and acting through the thrust on the pump plunger. The traction force on the movable secondary element appears due to the interaction of currents induced in it with the traveling magnetic field of the linear inductor, created by multiphase windings connected to the power source. Such an electric motor is used in rodless pumping units (AS USSR No. 491793, publ. 1975) / 2 / and (AS USSR No. 538153, publ. 1976) / 3 /. However, the operating conditions of submersible plunger pumps and linear asynchronous motors in the well impose restrictions on the choice of the design and size of electric motors. A distinctive feature of submersible CLAD is the limited diameter of the engine, in particular, not exceeding the diameter of the tubing. For such conditions, known electric motors have relatively low technical and economic indicators: Efficiency d. and cos are inferior to those of conventional induction motors; The specific mechanical power and tractive effort (per unit length of the engine) developed by the CLAD are relatively small. The length of the engine placed in the well is limited by the length of the tubing (no more than 10-12 m). When the length of the motor is limited, it is difficult to achieve the pressure required to lift the fluid. A slight increase in tractive effort and power is possible only due to an increase in the electromagnetic loads of the engine, which leads to a decrease in efficiency. and the level of reliability of motors due to increased thermal loads. These disadvantages can be eliminated by performing a "reverse" circuit "inductor-secondary element", in other words, the inductor with windings is placed inside the secondary element. Such an execution of a linear motor is known ("Induction electric motors with an open magnetic circuit." Informelectro, M., 1974, pp. 16-17) / 4 / and can be taken as the closest to the claimed solution. The known linear motor contains a cylindrical inductor with a winding, mounted inside a secondary element, the inner surface of which has a highly conductive coating. Such a design of the inductor in relation to the secondary element was created to facilitate the winding and installation of the coils and was used not as a drive for submersible pumps operating in wells, but for surface use, i.e. without strict limitation on the dimensions of the motor housing. The objective of the present invention is to develop a design of a cylindrical linear induction motor for driving submersible plunger pumps, which, under conditions of limited diameter of the motor housing, has increased specific indicators: tractive effort and power per unit length of the motor while ensuring the required level of reliability and a given energy consumption. To solve this problem, a cylindrical linear asynchronous motor for driving submersible plunger pumps contains a cylindrical inductor with a winding mounted inside a secondary element, the inner surface of which has a highly conductive coating, while the inductor with windings is designed for axial movement and is mounted inside the tubular electric motor housing, the thickness of steel the walls of which are not less than 6 mm, and the inner surface of the case is covered with a layer of copper not less than 0.5 mm thick. Taking into account the unevenness of the surface of the wells and, as a consequence, the possible bending of the electric motor housing, the inductor of the electric motor should be made consisting of several modules interconnected by a flexible connection. In this case, to equalize the currents in the phases of the motor winding, the number of modules is chosen as a multiple of the number of phases, and when moving from one module to another, the coils are stacked with alternating changes in the location of individual phases. The essence of the invention is as follows. The use of a steel motor housing as a secondary element allows the most efficient use of the limited space of the well. The maximum achievable values of the power and effort of the motor depend on the maximum permissible electromagnetic loads (current density, magnetic induction) and the volume of active elements (magnetic circuit, winding, secondary element). The combination of a structural element of the structure - an electric motor housing with an active secondary element - makes it possible to increase the volume of active materials in the engine. An increase in the active surface of the engine makes it possible to increase the thrust and power of the engine per unit of its length. An increase in the active volume of the engine makes it possible to reduce the electromagnetic loads that determine the thermal state of the engine, on which the level of reliability depends. At the same time, obtaining the required values of the tractive effort and engine power per unit of its length while ensuring the required level of reliability and a given energy consumption (efficiency and cos) under conditions of limitation on the diameter of the engine housing is achieved by the optimal selection of the thickness of the steel wall of the engine housing, as well as the thickness of the highly conductive coating of its core - the inner surface of the vessel. Considering the nominal speed of movement of the working parts of the plunger pump, the optimal speed of the running magnetic field of the movable inductor corresponding to it, possible technological difficulties in the manufacture of windings, acceptable values of the pole division (not less than 0.06-0.10 m) and the frequency of the inductor current (not more than 20 Hz), the parameters for the thickness of the steel wall of the secondary element and the copper coating are selected in the declared manner. These parameters allow, under conditions of limited motor diameter, to reduce power losses (and, consequently, to increase efficiency) by eliminating an increase in the magnetizing current and a decrease in magnetic flux leakage. The new technical result achieved by the invention consists in the use of an inverse circuit "inductor-secondary element" for the most efficient use of the limited space of the well when creating a cylindrical linear induction motor with characteristics that allow it to be used as a drive for submersible pumps. The claimed engine is illustrated by drawings, where figure 1 shows a general view of a motor with a modular inductor, figure 2 - the same, section along AA, figure 3 shows a separate module, figure 4 - the same, section according to BB. The engine contains a body 1 - a steel pipe with a diameter of 117 mm, with a wall thickness of 6 mm. The inner surface of the pipe 2 is covered with copper with a layer of 0.5 mm. Inside the steel pipe 1, using centering sleeves 3 with anti-friction gaskets 4 and pipe 5, a movable inductor is mounted, consisting of modules 6, interconnected by a flexible connection. Each of the inductor modules (Fig. 3) is made up of separate coils 7, alternating with annular teeth 8, having a radial slot 9, and placed on the magnetic circuit 10. The flexible connection consists of the upper 11 and the lower 12 clamps, movably mounted using grooves on the protrusions of adjacent centering bushings. On the upper plane of the clamp 11, the current supply cables 13 are fixed. In this case, to equalize the currents in the phases of the inductor, the number of modules is chosen as a multiple of the number of phases, and when passing from one module to another, the coils of individual phases are alternately interchanged. The total number of inductor modules, and hence the motor length, are selected depending on the required tractive effort. The electric motor can be equipped with a rod 14 for connecting it to a submersible plunger pump and a rod 15 for connecting it to a power supply. In this case, the rods 14 and 15 are connected to the inductor by flexible coupling 16 to prevent the transfer of the bending moment from the submersible pump and the current supply to the inductor. The electric motor has passed bench tests and operates as follows. When a submersible electric motor is supplied with power from a frequency converter located on the surface of the earth, currents appear in the multiphase winding of the motor, creating a traveling magnetic field. This magnetic field induces secondary currents both in the highly conductive (copper) layer of the secondary element and in the steel housing of the motor. The interaction of these currents with a magnetic field leads to the creation of a traction force, under the action of which the movable inductor moves, acting through the thrust on the pump plunger. At the end of the travel of the moving part, at the command of the sensors, the engine is reversed by changing the phase sequence of the supply voltage. Then the cycle is repeated. With a motor diameter of 117 mm, an inductor length of 1400 mm, an inductor current frequency of 16 Hz, the electric motor develops a force of up to 1000 N and a power of 1.2 kW with natural cooling and up to 1800 N with oil cooling. Thus, the claimed engine has acceptable technical and economic characteristics for its use in combination with a submersible plunger pump for the production of formation fluids from medium and large depths. A cylindrical linear asynchronous motor for driving submersible plunger pumps, containing a cylindrical inductor with a multiphase winding, made with the possibility of axial movement and mounted inside a steel secondary element, the steel secondary element is an electric motor housing, the inner surface of which has a highly conductive coating in the form of a copper layer, characterized in that that the cylindrical inductor is made of several modules, recruited from phase coils and interconnected by flexible coupling, the number of cylindrical inductor modules is a multiple of the number of winding phases, and when moving from one module to another, the phase coils are stacked with alternating changes in the location of individual phases. In 2010, Mitsubishi's NA series EDM machines were equipped with cylindrical linear motors for the first time, surpassing all similar solutions in this area. Compared to ball screws, they have a significantly greater margin of durability and reliability, are capable of positioning with higher accuracy, and also have better dynamic characteristics. For other linear motor configurations, CLDs benefit from overall design optimization: less heat generation, higher economic efficiency, ease of installation, maintenance and operation. Considering all the advantages that the CLD have, it would seem, why even tinker with the drive part of the equipment? However, not everything is so simple, and a separate, isolated, point improvement will never be as effective as updating the entire system of interconnected elements. Therefore, the use of cylindrical linear motors is not the only innovation implemented in the drive system of Mitsubishi Electric EDM machines. One of the key transformations that made it possible to take full advantage of the advantages and potential of the CLD to achieve unique indicators of accuracy and equipment productivity was a complete modernization of the drive control system. And, unlike the engine itself, the time has already come for the implementation of our own developments. Mitsubishi Electric is one of the world's largest manufacturers of CNC systems, the vast majority of which are manufactured directly in Japan. At the same time, the Mitsubishi corporation includes a huge number of research institutes conducting research, including in the field of drive control systems, CNC systems. It is not surprising that in the company's machines, almost all electronic filling is of its own production. Thus, they implement modern solutions that are maximally adapted to a specific line of equipment (of course, this is much easier to do with your own products than with purchased components), and at the lowest price, maximum quality, reliability and performance are ensured. A striking example of the practical application of our own developments was the creation of a system ODS- Optic Drive System. The NA and MV series of machine tools were the first to use cylindrical linear motors in feed drives controlled by third generation servo amplifiers. A key feature of the Mitsubishi servo amplifiers family MelServoJ3 is the ability to carry out communications using the protocol SSCNET III: communication of motors, feedback sensors through amplifiers with the CNC system occurs via fiber-optic communication channels. At the same time, the data exchange rate increases almost 10 times (in comparison with the systems of previous generations of machine tools): from 5.6 Mbit / s to 50 Mbit / s. Due to this, the duration of the information exchange cycle is reduced by 4 times: from 1.77 ms to 0.44 ms. Thus, the control of the current position, the issuance of corrective signals occurs 4 times more often - up to 2270 times per second! Therefore, the movement occurs more smoothly, and its trajectory is as close as possible to the given one (this is especially important when moving along complex curvilinear trajectories). In addition, the use of fiber-optic cables and servo amplifiers operating under the SSCNET III protocol can significantly increase the noise immunity (see Fig.) And the reliability of information exchange. In the event that the incoming pulse contains incorrect information (the result of interference), then it will not be processed by the engine, instead, the data of the next pulse will be used. Since the total number of pulses is 4 times greater, such a skipping of one of them minimally affects the movement accuracy. As a result, the new drive control system, thanks to the use of third-generation servo amplifiers and fiber-optic communication channels, provides a more reliable and 4 times faster data exchange, which makes it possible to implement the most accurate positioning. But in practice, these advantages do not always turn out to be useful, since the control object itself - the engine, due to its dynamic characteristics, turns out to be unable to work out control pulses of such a frequency. That is why a combination of servo amplifiers is most justified. j3 with cylindrical linear motors in a single ODS system used in the NA and MV series machines. The CLD, due to its excellent dynamic properties - the ability to work out huge and insignificant accelerations, move stably at high and low speeds, has a huge potential to improve positioning accuracy, which is helped by the new control system. The motor responds with ease to high-frequency control pulses for precise and smooth movement. However, the benefits of an EDM machine equipped with an ODS system are not exclusively limited to improving positioning accuracy... The fact is that obtaining a part with a certain accuracy and roughness on an electrical discharge machine is achieved when the electrode (wire) moves at a certain speed along the trajectory and in the presence of a certain voltage and distance between the electrodes (wire and workpiece). The values of feed, voltage and electrode spacing are strictly defined for each material, processing height and desired roughness. However, the processing conditions are not strictly defined, just as the material of the workpiece is not homogeneous, therefore, in order to obtain a suitable part with the given characteristics, it is necessary that at each particular moment of time the processing parameters change in accordance with changes in the processing conditions. This is especially important when it comes to obtaining micron accuracy and high roughness values. And it is also extremely necessary to ensure the stability of the process (the wire should not break, there should be no significant jumps in the magnitude of the speed of movement). This problem is solved with the help of adaptive control. The machine independently adjusts to changing processing conditions by changing the feed rate and voltage. How quickly and correctly these amendments are made depends on how accurately and quickly the workpiece will turn out. Thus, the quality of the adaptive control work to a certain extent determines the quality of the machine itself through its accuracy and productivity. And this is precisely where the advantages of using the CLD and the ODS system as a whole are fully manifested. The ability of the ODS to provide processing of control pulses with the highest frequency and accuracy has improved the quality of adaptive control by an order of magnitude. Now the processing parameters are corrected up to 4 times more often, moreover, the overall positioning accuracy is higher. Only complex, but, nevertheless, fully justified and proven design changes can be the key to improving the quality (as an aggregate indicator of the level of reliability and technological capabilities of equipment) and the competitiveness of the machine. Changes for the Better is Mitsubishi's motto.Work text Bazhenov, Vladimir Arkadevich, dissertation on Electrotechnology and electrical equipment in agriculture
Drawings for RF patent 2266607
CLAIM
Y-axis drive of Mitsubishi Electric MV1200R EDM machine
Mitsubishi NA and MV machines have been equipped with the first of its kind Optic Drive System
Mitsubishi machines produce parts with outstanding precision and roughness. Positioning accuracy is guaranteed for 10 years.
Processing monitor. The speed graph is shown in green, which shows the operation of the adaptive control.
Carbide alloy, height 60 mm, roughness Ra 0.12, max. error - 2 microns. Part received on a Mitsubishi NA1200 machine
Summing up some results, we can say that the use of CLDs in Mitsubishi Electric machines would not have been such an effective step, which would have allowed reaching new heights of both accuracy and processing productivity without the introduction of an updated control system.
