SU649114A1 - Electric drive with ac machine - Google Patents

Description

In transitional regimes, the unified law of regulation of c; | .. gsop91 is unacceptable,

The aim of the invention is to increase the energy performance of the electric drive.

This is achieved in that a second electric drive unit and a speed control channel and a speed control channel with a reference unit, a speed regulator and a dividing device are introduced into the proposed electric drive with an alternating current machine comprising a thyristor frequency converter, a speed coupling channel with a reference unit, a speed controller and a dividing device, control key with a control unit, an inverting amplifier, an adder and a computing device. The inputs of the latter are connected to the outputs of the second task setting unit The above mentioned divider device and the output through the single inputs of the summator and the controlled key to the input of the comparison node of the flow coupling regulator. The second input of the adder through the inverting amplifier is connected to the output of the first task setting unit of the flux linkage set speed.

The drawing shows a functional diagram of the proposed electric drive. One channel of the electric drive control system consists of an integral-proportional regulator 1 of the rotor flux linkage, a regulator of the magnetizing current of the stator 2, and the other channel of the integrator 3, which includes the limiting amplifier 3 and the integrator 4, filter 5, the SP-6 speed regulator, dividing the devices 7 and the I-regulator of the active current of the rotor 8. The regulators in each channel are interconnected according to the principle of slave regulation.

In addition, the device has a compensating coupling unit 9, which includes multiplying devices 10, 11, 12, and two adders, the outputs of which are connected to the inputs of the direct coordinate conversion unit 13. The latter generates signals for setting the stator phase currents21 j2I; g, 2; c They are developed in corresponding circuits with P-regulators of phase currents 14, the output signals of which are fed to the inputs of phase control systems of a frequency converter with direct connection 15, feeding the stator of an asynchronous motor 16.

The device also has an inverse coordinate transformation block 17, generating signals rotor flux linkage VP magnetizing CD and active igg stator currents, as well as signals of homonomic functions iln V, cOi At the angle y between the generalized vector,., flux coupling of the rotor f, and the magnetic axis of the stator phase L. The input of this unit is fed by signals from the stator current sensors 18, 19, Hall sensors 20, 21 installed in the engine air gap, and tacho generator 22.

The task block in the flow link control channel forms the minimum rotor flow link setpoint (|). The second task block, which forms the nominal main flow coupling setpoint, is introduced into the electric drive. Output it through the input computing device 23, the adder 24 and the control key 25 is connected to the input node

comparisons of the flux linkage controller. The computing device is also connected to the output of the dividing device 7 in the control channel of the network with a signal (2 g. To the adder 24

through inverting amplifier 26

the output of the first block of the flow of coupling with a signal 1 ,,.,. The key 25 is controlled by a control unit 27 connected to the output of the limiter 3 in

speed control channel setting unit.

In the steady state, the expression is true

V6 VVp4K.b, g.i2s (1)

where C) is the flux linkage of the air gap;

CR is the coupling coefficient of the rotor; OiipE rotor scattering inductance.

B idle mode then, taking into account the expression (1), we get

i nxxVs.H. (2) where VBH is the nominal flux linkage of the air lock selected on the knee of the magnetization curve.

The minimum flux linkage of the rostor is set so that with a maximum dynamic active current of 25 ° d the nominal flux linkage of the air gap is achieved:

Vp "HH 1 4.r (, icf

denote

A V V g-4 g 2sf -

gmina

M)

Computing device 23 implements the dependence on n analog analog elements defined by the radical expression in (4). When key 25 is closed ng. the input of the reference of the regulator 1 through the filter 28 turns off the signal

(K, -U, e4,) Sf5)

where the asterisks denote the settings 65 corresponding variables, in contrast

on their values in physical units. Obviously, if regulator 1 provides a change in accordance with expression (5)

  CQnst (6)

The V 6 con at mode, in accordance with coupling (6), is advisable to provide in steady state under different loads, i.e. in the enhanced mode, the key 25 must be closed. If in the established mode (as well as in dynamics) Fg.min const is supported, then C) g is significantly lower than 15 c at nominal loads, which reduces the energy indices (power factor and efficiency).

The key 25 is controlled by a block 27, which in the simplest case represents a logical element of the type NOT. In transient modes, the input of the integrator 4 has a different signal (zero), and the output 27 has a zero signal, therefore, the key 25 is open. In the steady state, there is a zero signal at the input of the integrator 4, therefore, at output 27, a different signal (one) appears and the key 25 is closed.

In the mine hoist drive, the key 25 may also be implemented as a function of time or the path according to the signals of the respective sensors (see arrows in the drawing).

The actuator operates in the most characteristic mode as follows. First, a driver signal is supplied through filter 28 to the input of controller 1, which produces the setpoint for controller 2. The latter generates the setpoints of the phase current regulators. The transition process of the setpoint of the given value C) p is formed by the joint action of all the specified regulators.

Then, to input 6, through the filter 5, a speed command signal is supplied from the integrating device. In this case, the key 25 is open. Simultaneously, the output of the regulator 6 generates a signal for setting the electromagnetic moment, which, after passing through the separating device 7, generates a signal for setting the active stator current. I The speed control loops, the active and magnetizing currents of the stator together with the phase current control loops form a typical electromagnetic moment diagram.

corresponding to the prescription of a symmetric optimum. As a result, there is a rapid acceleration of the asynchronous 1G engine to a given speed.

After reaching a predetermined speed at the input of the integrator I, a zero signal appears, the key 25 closes and in the installation mode maintains the constancy of the main flux linkage.

Thus, a pre-installed electric drive ensures optimum use of the engine in a steady-state mode, increases energy performance while maintaining high dynamic properties in transient conditions.

Claims (2)

1. An electrical drive with an AC machine, comprising a thyristor frequency converter, a flow coupling control channel with a first reference unit and a flow coupling controller, and a speed control channel with a reference unit, a speed controller and a dividing device, characterized in that In order to improve energy performance, a second flow linking reference unit, a control key with a control unit, an inverting amplifier, an adder and a computing device, whose inputs are connected to the outputs of the second flow coupling reference unit and the splitter, are entered into it, and the output through one of the accumulator inputs and a controllable key to the input of the comparison node of the flux linkage regulator, while the second input of the adder is connected via an inverting amplifier to the output of the first task block Heat, and the input of the key management unit - to the speed reference unit. 2. The drive according to claim 1, wherein the inputs of the key control unit are connected in addition to the outputs of the track or time sensors. Sources of information taken into account in the examination 1. Siemens-S 1971, 45, 10, S. 761-764. 2. The patent of Germany 1941312, cl. 21 C 59/36, 1971.