SU1379932A2 - Variable=frequency electric drive - Google Patents

Abstract

The invention relates to electrical engineering. Purpose (The invention is to improve the accuracy of controlling the torque of an induction motor in dynamic modes due to skid correction based on information about the phase angle of the motor and the rotor flux linkage. This goal is achieved by introducing a deviation calculator from the setpoint the values of the modulus of the flux-coupling vector, the flux-linking regulator 19, the function converter 20 of the torque reference signal into the correction signal flux couplings and adders 21 and 22. As a result, it becomes possible without additional sensors to obtain additional information about the state of the machine in the form of a slip correction signal for the rotor flux adhesion, which improves the accuracy of the regulation of the stator current vector argument - angle 9, and therefore , and the time of the asynchronous motor, 1 Cp f-crystals, 1 il. S (L

Description

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The invention relates to electrical engineering, namely, frequency-controlled electric drives based on asynchronous motors and valve variable frequency drives, can be used in control systems for various purposes with high demands on the accuracy of torque control and is an improvement of the invention according to the author, St. No. 1292156.

The drawing shows a functional block diagram of a variable frequency drive.

The purpose of the invention is to improve the accuracy of the regulation of the torque of an asynchronous motor in a dynamic mode due to slip correction based on information about the phase angle of the motor and the rotor flux linkage.

Variable frequency drive contains an asynchronous motor.

1 connected to the inverter outputs

2, the inputs of which are connected to the outputs of the controlled rectifier 3. The control input of the controlled liter Mi-3 is connected to the output of the current regulator A.

The driver input of current regulator 4 is connected via a function converter 5 of a torque reference signal to a reference signal of a stator current vector modulus with the output of speed controller 6. The feedback input of the speed regulator 6 is connected to the output of the rotation speed sensor 7 and the output of the speed regulator 6 to the input of the function torque converter function 8 to the slip task signal and the output signal of the torque signal function signal converter 9

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Phase angle equalizer 13 to the angle between the stator current vectors and rotor coupling is connected to the output of the phase angle sensor 14, the inputs of which are connected to the outputs of the sensors 15 and 16 phase currents and voltages, respectively. With the output of the functional converter 9, the input of the angle adjuster 17 is connected,

The variable-frequency drive includes a block 18 for calculating deviations from the setpoint value of the rotor flux-coupling vector module, a two-input flux linkage regulator 19, a torque reference function converter 20 for the linkage correction signal and two additional adders 21 and 22. The adder 21 is connected with the first input and output, respectively, to the output of the functional converter 9 of the signal of setting the moment to the signal of setting the angle between the stator current and rotor flux current vectors and to the controller input SFA 17. The adder 22 connected to the first input and output respectively to the output of the regulator 17 and the angle of the ground to the second input of the adder 12. A second input of the adder 21 is connected to the output of the function generator 13, the phase angle in the angle between stator current and rotor flux linkage. The inputs of the unit 18 for calculating deviations from the setpoint value of the modulus of the rotor flux linking vector are connected respectively to the inputs of the adders 21 and 22, and its output is connected to the first input of the flux linkage regulator 19 connected to the output of the second adder of the torque reference signal 20 to the flux correction signal

The angle between the current vector d is connected to the output, respectively.

speed regulator 6 and to the second input of the flux linkage regulator I9.

stator and rotor flux linkage. The feedback input of current regulator 4 is connected to the output of current sensor 10. The electric drive also contains an inverter control system 11 and a main adder 12. The first input of the adder 12 is connected to the output of the rotational speed sensor 7, the second input to the output of the rotational frequency regulator 6 via

functional converter 8 sig-. which form the inputs of the controller

Setting the torque reference to the slip reference signal. The output of the adder 12 is connected to the input of the inverter control system I1. Functional transformation of flux linkage.

Frequency-controlled electric water works as follows.

connected respectively to the output

speed regulator 6 and to the second input of the flux linkage regulator I9.

The flux linkage regulator 19 is provided with a multiplication unit 23 and an amplifier 24, the output of which forms the output of the flux linkage regulator 19, while the input of the amplifier 24 is connected to the output of the multiplication unit 23, inputs

19 flux linking.

Variable frequency drive works as follows.

Two signals are fed to the input of the speed regulator 6 — a signal for setting the rotation frequency and feedback on the rotation frequency from the rotation sensor 7. The output of the speed controller 6 is proportional to the setpoint value of the slip frequency of the rotor. This signal is fed to the inputs of functional converters 5, 8 and 9. Functional converter 5 generates a reference signal for the stator current control loop, which is fed to the input of current regulator 4. The current feedback signal comes from the current sensor 10 and is fed to the feedback input of the current regulator 5, the output of which controls the rectifier 3. The output from the output of the speed regulator 6 sets the reference value of the required torque Functional converter 8. After adding the slip signal to the feedback signal from the rotational speed sensor 7, the resultant signal determines the frequency of the inverter and enters the inverter control system I1. The tuning of the functional transducers 5 and 8 is determined by the selected frequency control law.

To improve the accuracy in dynamic modes, the system additionally produces a slip correction signal, accelerating the transfer of the stator current vector to a new position corresponding to the required electromagnetic torque of the induction motor 1. The correction signal, LSFC, is fed to the second input of the adder 12, which is added to the reference slip signal DIO In this case, the reference slip characterizes the slip value in a steady state with a given moment, and the slip correction signal takes into account It provides the electromagnetic transient process of the asynchronous machine and provides the necessary frequency boost.

The slip correction signal is generated by the angle adjuster 17, i.e. Chapter 9 between the stator current vector i (. and the rotor flux linkage (pp as a function of the mismatch of the given and actual angle values 6, as well as estimates of the deviation of the modulus of the rotor flux vector of the rotor A (p,

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The signal characterizing the angle 9 is removed from the sensor 14 of the phase angle. The signal, which characterizes the angle 0, is connected to the measured phase angle tf using the functional converter 13. The signal proportional to the measured angle H is compared on the adder 21 with the reference signal on the angle S received from the functional converter 9, and is fed to the control input torus 17 angle. The reference signal for the angle 9 comes from the rotation speed controller 6 through the functional converter 9, which realizes the dependence of the angle 0 on the electromagnetic moment of the machine, corresponding to the selected frequency control law.

To improve the accuracy of torque control in dynamic modes, there is not enough information only about the angle E, it is also necessary to have information about the rotor flux linkage vector. The expansion of the vector input variables is achieved by applying a reduced first-order observing device - block 18 to determine the deviation from the set value of the modulus of the rotor flux vector; in which, on the basis of the angle mismatch signals - L9 and the output signal of the angle adjuster 17 -L CO, a signal is generated that characterizes the deviation from the set value of the rotor flux-coupling vector modulus (|). This signal is fed to the input of the rotor flux linkage regulator 19, to / another input of which a signal is received from the function setpoint signal converter 20 to the trimming signal signal of the rotor flux linkage signal. At the output of the flux coupling regulator 19, a slip correction signal is generated along the flow to the coupling of the rotor. The summed correction signal SSC consists of a correction signal for deviation "of angle b and deviation of the rotor flux linkage.

Thus, the introduction of a variable-frequency regulator, a functional reference signal to a trim signal adjustment signal of the rotor flux-regulator and additional adders, into a frequency-controlled electric drive, allows additional information about the state of the machine and increasing the dynamic accuracy of the stator current vector control without the use of coupling sensors. - angle b, and, therefore, and the engine torque in comparison with the known electric drive.

Claims (2)

Invention Formula 1, Variable-frequency electric drive, autom.St. No. 1292156, which is based on the fact that, in order to improve the accuracy of torque control of an induction motor, a deviation calculation unit was introduced from a given value of the rotor flow clutch vector module, a two-input flow control regulator the time command to the signal of the correction of the line coupling and two additional adders, the first of which is connected by the first input and the output, respectively, to the output of the function converter Ktorov stator current and rotor flux linkage and to the entry angle regulator torus, wherein the second additional adder connected to the first input and output respectively to the output of regulator angle and to the second input of the main adder, the second input of the first additional adder is connected to the output of the function converter of the phase angle to the angle between the stator current and rotor flux current vectors, the inputs of the deviation calculator from the set value of the rotor flux vector vector modulus, respectively and its output is to the first input of the flux linkage regulator connected by the output to the second input of the second additional adder, and the input to stroke functional transducer torque reference signal into a signal cor- rektsii flux linkage connected respectively to the output frequency of the rotation regulator and to the second input of the regulator flux linkage torus. 2. The actuator according to claim 1, wherein the flow coupler is equipped with a multiplication unit and an amplifier, the output of which forms the output of the flow coupler, and the input of the amplifier is connected to the output of the multiplication unit, the inputs of which form torus flux linkage.