SU758453A1 - Device for regulating induction phase-wound rotor motor speed - Google Patents

Description

Resistors 2, 3, and 4 with parallel-connected triacs 5, 6, and 7, speed sensor 8, and three pulse-phase control units, consisting of timing 9, which includes synchronizing transformers 10, connected in parallel with triacs 5, 6, and 7. Single-phase bridge rectifier 11 and a limiting circuit 12, a saw-tooth voltage generator 13, receiving power from a rectifying bridge 14 connected to the rotor circuit, connected in series to the zero-body 15, impulse generator 16, amplifier 17, back block audio 18 connected to the input of the adder 19 and the matching stage 20.

The device works as follows. When voltage is applied to the stator circuit of an asynchronous three-phase motor and with the set voltage U, the motor will operate on a rheostat characteristic determined by resistors 2, 3 and 4. The pulse-phase control system in this case will supply clock pulses to the control electrodes of the triacs, which are produced when the rotor voltages go through zero. For each half period, sims for 1Gerts and there is a full additional resistance in the rotor circuit.

For operation at a given speed in task block 18 a certain value of the driving voltage is set. This voltage enters the adder 19,; and the difference of the two voltages Uj-Ujjj enters the amplifier 17, where and is the driving voltage corresponding to the selected speed; U is the speed feedback voltage taken from speed sensor 8.

The reinforced voltage is applied to one of the inputs of the null organ 15.

The second input of the comparison device is supplied with the voltage of the generator 13.

The beginning of the charge of the capacitor of the generator 13 is strictly synchronized with the moment of transition of the half-wave phase voltage through zero, which is achieved due to the presence of synchronizing transformers 10 and a single-phase bridge rectifier 11. The charge rate of the capacitor, and hence the inclination of the saw, changes in accordance with the period change phase voltage, which allows to automatically compensate for the change in the control angle when the phase voltage frequency is changed. This effect is achieved by supplying power to the sawtooth generator from a three-phase bridge rectifier bridge 14 connected to the rotor circuit.

At the input of the null organ 15, when the sawtooth voltage becomes equal to the voltage coming from the amplifier 17, the driver 16 produces a control pulse., The amplified control pulses include switching simistors 5. 6 and 7, which short the resistors 2, 3 and 4 rotors in each half-phase voltage.

In steady-state mode, an asynchronous motor operates on an artificial mechanical characteristic, which is determined by the magnitude of the calculated active resistance of the rotor, depending on the duty cycle of the commutation.

Durability is determined by the angle of control a, which can vary in this device from 180 to 10 °.

In a device for adjusting the speed of an asynchronous motor with a slip change, the voltage of the rectifier bridge 14 feeds the saw-tooth voltage generator 13, which leads to a change in the inclination of the saw and the angle of control of the triacs 5, 6, 7 and allows

improve the accuracy of maintaining a given speed.

F o

rmula of invention

A device for controlling the speed of a three-phase asynchronous motor with a phase rotor, containing resistors connected by a star and connected to the rotor windings, triacs connected in parallel to the resistors, three units of pulse-phase control, consisting of a series-connected synchronization unit connected in parallel to the triacs of a sawtooth generator , zero-organ and pulse generator, connected to the control circuit of the triacs, adder, one input of which is connected to the speed sensor The motor and the other with the task unit, the output of the adder are connected to the control inputs of the pulse-phase control units via an amplifier, characterized in that, in order to increase the control accuracy, a rectifier is introduced, the input of which is connected to the rotor windings, and the output is connected to the generator of a ramp tension

Sources of information taken into account in the examination

1. Japanese Patent No. 43-12856, cl. 55 C 222, published. 1968.

2. Petrov, L.P., et al. Simulation of thyristor-controlled asynchronous electric drives, M., Energie, 07.01.77, p. 144- Il47, 181.

Claims (1)

Claim A device for controlling the speed of a three-phase asynchronous motor with a phase rotor, containing resistors connected by a star and connected to the rotor windings, 35 triacs connected in parallel with resistors, three pulse-phase control units consisting of synchronization units connected in series connected in parallel to a triac of a sawtooth generator 4Q voltage , a zero-body and a pulse shaper connected to the control circuit of the triacs, an adder, one input of which is connected to the speed sensor motor and the other with the reference unit, the output of the adder is connected ₄₅ to the control inputs of the pulse-phase control units via an amplifier, characterized in that, in order to increase the accuracy of regulation, a rectifier is introduced, the input of which is connected to the windings of the torus ₅₀ and the output is connected to sawtooth generator.