SU1534732A1 - Ac electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used in areas of industry where load speed regulation is required. The purpose of the invention is to simplify the design of the electromechanical part of the drive. A switching unit 8 of power switches, two adders 11 and 19, two detents 9 and 10 of zero order, a current source 17, the output of which is connected to the excitation winding of the synchronous motor 16, are entered into the AC electric drive. As a result, 2-4 signals are formed at the inputs of multipliers reference harmonic angle functions without using a rotor position sensor. 1 hp ff, 3 ill.

Description

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The invention relates to electrical engineering and can be used in areas of industry where load speed regulation is required.

The purpose of the invention is to simplify the design of the electromechanical part of the drive.

Fig. 1 shows a functional diagram of an electric drive with a synchronous D gatel with an excitation winding; FIG. 2 is a functional diagram of the switching unit of power switches; FIG. 3 diagrams illustrating the operation of the circuit.

The actuator fig.O contains

block 1 of setting the moment, multipliers 2–4 signals, regulators 5–7 currents; block 8 of switching of power switches, satchers 9 and 10 of zero order, adder 11 with inverting; power unit 12, sensors 13-15 currents, synchronous motor (SD) 16, current source 17, excitation winding 18 of motor synchronously, adder 19, generator 2, counter 21, read-only memory (ROM) 22, switching keys 23-25.

The output of the moment setting unit 1 is connected to the inputs of multipliers 2-4 signals, the other inputs of which are connected to the outputs of clamps 9 and K of zero order and the output of adder 11 with inverting, and their outputs are connected to the inputs of current regulators 5-7, the other inputs of which connected to the outputs of the current 13-15 sensors, the outputs of which are connected to the switching unit 8 of the power switches, some outputs of which are connected to the latches 9 and 10 of zero order, and its other outputs are connected to the inputs of the power unit 12, the outputs of which are through sensors 13 15 currents are connected to y ravl winding guide LED 16 on

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five

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mutating keys 23-25, connected to the outputs of the regulators 5-7 currents, and the outputs of these keys are connected to the power unit 12.

The drive works as follows.

From the output of the time setting unit 1 (Fig. 1), the voltage setting of the time U is supplied to the first inputs of the multipliers 2 to 4 signals, to the inputs of which the reference harmonic functions of the angle are fed. At the outputs of the multipliers 2-4 signals, the signals for setting the phase currents of the LEDs 16 are formed, which at the outputs of the current regulators 5-7 are compared with voltages proportional to the real phase currents of the LEDs taken from the sensors 13-15 currents. As a result of the comparison, the current-key control signals are generated by the current-voltage regulators 5-7, which are fed through the switching unit 8 of the power switches to the inputs of the power unit 12. On the basis of these signals, the switch switches are made, which means that the currents in the phases of the LED 16 correspond signal assignments. The amplitude of the phase currents is determined by the magnitude of the torque reference signal U, and the phase by the angular position of the rotor. Thus, an electromagnetic moment is formed at the output shaft of the LED 16, proportional to the product of the transverse component of the stator current determined by the signal on the current in the excitation winding 18, specified by the current source 17

The formation of the reference harmonic functions of the angle arriving at the second inputs of the multipliers 2-4 signals is carried out as follows. The generator 20 (FIG. 2), included in the switching unit 8 of the power switches,

a coil of excitation 18 of which the pins produce rectangular pulses

It is connected to the current source 17 and to the input of the adder 19, the output of which is connected to the inputs of the latches 9 and 10 of the zero order, the outputs of which are connected to the inputs of the adder 11 with inverting.

The switching unit of the power switches (FIG. 2) may comprise a pulse generator, the output of which is connected to the input of the pulse counter 21, which through the ROM 22 is connected to the same inputs of the switching switches 23-25, zero-order locks 9.10 (FIG. 1) and to control inputs com50

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high frequency U, (fig. 3), arriving at the counting input of the counter 21 "The binary exit code of the counter 21 changing in time goes to the input of the ROM 22. During the counting process, the counter 21 periodically overflows and the code combinations at its output over time repeated.

In the memory of the ROM 22, the data is recorded in such a way that when certain code combinations appear at its input, a synchronization pulse is generated at one of its outputs, which is applied to the control to generate square pulses.

the high frequency U, (FIG. 3) arriving at the counting input of the counter 21 "The time-varying binary code from the output of the counter 21 enters the input of the ROM 22. During the counting process, the counter 21 periodically overflows, and the code combinations at its output over time repeated.

In the memory of the ROM 22, the data is written in such a way that when certain code combinations appear at its input, a synchronization pulse is generated at one of its outputs, which is applied to the control inputs of the switching keys 23-25, resulting in a momentary shutdown the inputs of the power unit 12 from the outputs of the current regulators 5-7 and are connected respectively: the first two inputs to the outputs a and b of ROM 22, and the third input to zero potential, which corresponds to connecting phase C to the negative pole of the link constant The current is switched, but the phases A and B are switched according to the timing diagrams in FIG.

Thus, with the arrival of a pulse, the phase current regulation of the LED 16 is briefly stopped and the LED 16 is used as a position sensor, taking into account the fact that the mutual inductance between the stator windings and the excitation winding 18 changes harmonically as a function of the angular position .

With the arrival of a pulse (fig. 3), phase A of LED 16 is connected to the positive pole of the source, and phases B and C- to negative, resulting in the initiation of LED 16 along the axis of phase A. In addition, the magnet EMF is stored on lock 9 induced in the excitation winding 18. With the arrival of the pulse b, the winding B is connected to the positive pole of the source and the A and C phases to the negative pole, as a result of which the LED 16 is already excited along the B axis, and the EMF value induced in the excitation winding 18 is remembered in

the latch 10. Thanks to the above 40 Bat Two information outputs for the co-operations at the inputs of the multipliers of 2-4 signals, harmonic support functions of the angle are formed.

Thus, there is no need to use an angle sensor to form the reference harmonic functions of the angle. This simplifies the design of the electromechanical part of the drive.

Claims (2)

Invention Formula . An AC drive containing a synchronous motor, stator current sensors connected to the output of the power key block are connected to the input make contacts of the first two switching keys and are additional outputs of the power switching unit. 45 keys, the synchronization output of the memory device is connected to the control inputs of the switching keys, the closing input contact of the third switching key is connected to the common point of the control unit, the opening contacts of the switching key are inputs of the switching power switch, the output contacts of the switching keys are 55 outputs of the power switch switching unit. whose current regulators, the first inputs of which are connected via signal multipliers to the output of the torque setting unit, and their second inputs are connected to the outputs of current sensors, characterized in that, in order to simplify the design of the electromechanical part of the drive, switching power switches with additional inputs, two adders, two zero order clamps, a current source, and a synchronous motor is made with an excitation winding, while 5, the output of the current source is connected to the excitation winding of the synchronous motor and to the input of the first adder, the output of which is connected to the inputs of the second via zero-order locks 0 adder and another input of two voltage multipliers, the output of the second adder is connected to another input of the third voltage multiplier, the outputs of current regulators through the comm block 5 mutations of the power switches are connected to the inputs of the power switches, the additional outputs of the clocks zero 0 p. 2. The drive according to claim.), Characterized in that the switching unit of the power switches is made 5 in the form of three switching keys, a permanent storage device of the counter and a generator, the output of which through the counter is connected to the input of the permanent storage device are connected to the input make contacts of the first two switching keys and are additional outputs of the power switching unit. of the keys, the memory synchronization output of the storage device is connected to the control inputs of the switching keys, the closing input contact of the third switching key is connected to the common point of the control unit, the opening contacts of the switching keys are the inputs of the switching switch of the power switches, the output contacts of the switching keys are the outputs of the switching unit power switches. Na6l.P FIG. I