SU1239825A1 - Electric drive - Google Patents

Abstract

The invention relates to electrical engineering, in particular to control electric drives. The purpose of the invention is to simplify the drive and maintain a minimum of losses. The electric drive contains an asynchronous machine 1 with a phase rotor, sensors of 2-4 phase currents and corresponding controlled sources of 5-7 phase currents, a speed sensor 8, a reference element 9. Sum-, mators 12 and 13, regulator 14 ratios of derived phase currents and three differentiation elements 15-17 are introduced into the electric drive. The introduction of these nodes into the electric drive allows to ensure that the sum of the derived phase currents and the sum of the finite currents are zero. This corresponds to the acquisition of a three-phase system with a blue co-current that satisfies the condition of minimum losses at a given speed, and simpler technical means are used. 1 il. Q & (Lu soo 00 yu ate

Description

"

The invention relates to electrical engineering, in particular to controlled electric motors, electric drives based on induction machines with a phase rotor, and can be used

minimizes losses and simplifies construction.

 The aim of the invention is to simplify an asynchronous electric drive and maintain a minimum of losses.

The drawing shows a functional diagram of an asynchronous electric drive.

The scheme contains an asynchronous machine 1 with a phase rotor connected via sensors of 2-4 phase currents to the outputs of the respective controlled sources of 5-7 phase currents connected in series, speed setpoint 8, reference element 9 and speed controller 10, speed sensor 11, mounted on the shaft of an asynchronous machine 1 with a phase rotor and a connected output to the subtraction input of reference element 9. The first 12 and second 13 adders, regulator 14 ratios of derived phase currents, and ttei of differentiation element 15-17 connected by inputs to the outputs of the respective sensors 2-4 phase currents are introduced into the asynchronous electric drive.

. The outputs of the differentiation elements 15-17 are connected to the inputs of the first adder 12 connected by an output to the input of the controller 14 of the ratio of the derived phase currents. The inputs of the second adder 13 are connected to the outputs of the sensors 2-4 phase currents. The output of the speed regulator 10, the output of the regulator 14 of the ratio of the derived phase currents and the output of the second adder 13 are connected to the inputs of the corresponding regulated sources of 5-7 phase currents.

Asynchronous electric drive works as follows.

When the actual speed of rotation of the asynchronous machine 1 with the phase rotor deviates from the set speed at the output of the comparison element 9, the error signal acting through the speed regulator 10 on the adjustable source 5 of the phase current with the output current IQ, is obtained.

1239825

A change in current i leads to a disturbance of the three-phase system of currents t

, (And to the violation of the conditions:

fb dt

(one)

dt

- z 0

The corresponding derivatives of the phase currents are formed using differentiation elements 15-17. The output of the adder 12 is Vits and the signal acting through the controller 14 is the ratio of the derived phase currents to the controlled current source 6 with the output current ((.5 which will change until condition (1) is again met.

Simultaneously with the change of currents

and

B

output signal changes

adder 13, acting on the adjustable source 7 of the phase current with an output current 1, until then, until the condition is met:

+ L. 0.

(2)

This way, the introduction of two adders, three differentiation elements and the ratio of the derivative of the phase currents into the asyn-, horny electric drive allows to ensure the fulfillment of conditions (1) and (2), i.e. equality to zero of the sum of derived phase currents and the sum of phase currents. This corresponds to obtaining a three-phase system of sinusoidal currents satisfying the condition of minimum losses at a given speed, and more simple technical means are used in comparison with the known mode.

Claims (1)

Invention Formula Electric drive containing an asynchronous mask with a phase rotor connected via sensors of phase currents to the outputs of the respective controlled sources of phase currents, serially connected speed controller, reference element and speed controller, speed sensor mounted on the shaft of the asynchronous machine with the phase rotor and connected output to the subtraction input of the comparison element, characterized in that, in order to simplify and maintain a minimum of losses, the first and second sum, the mators, the ratio controller pro3, 123982 are entered into it 54 of the derived phase currents and three element inputs of the second adder are connected to the differentiation, connected to the outputs of the sensors of the phase currents, and, to the outputs of the corresponding sensor-stroke of the speed regulator, the output of the adjustments of the phase currents, and outputs to the inputs of The torus ratios of the derivative phase leads of the first adder, the connected 5 currents, and the output of the second adder under the output to the controller input are related to the inputs of the corresponding rhenium derived phase currents, while the adjustable sources of phase currents.