SU658689A1 - Method of phasing electric drives with phase discriminators - Google Patents

Description

FIG. Figure 1 shows a functional diagram of an in-phase rotation system in which the method is implemented; in fig. 2 - time diagrams of atofi system operation.

The system comprises a leading motor 1, a rotational speed sensor of the leading motor 2, a device for separating two pulse sequences 3, a relay element 4, an integrator 5, a delay element 6, as well as a phase discriminator 7, an amplifier 8, a slave engine 9 and a feedback sensor 10, constituting the driven motor.

Consider the implementation of the proposed method in this system.

The cycle of its operation starts from the moment of feedback sensors 10 of the pulse foe being output (Fig. 2). At the same time, the phase discriminator 7 through the amplifier 8 turns off the power from the slave engine 9. At the same time, the separation device 3 determines the presence of time (phase) mismatch of pulses b and foe, exceeding the predetermined limits.

If the time interval between these pulses is longer than a predetermined g, the separation device 3 generates pulses fji and fiPc, which preserve the phase ratio of the initial pulses fj and f 3rf or — otherwise - generates a frequency pulse f. The relay element 4 registers the sign of the phase mismatch of the pulses f, and f, (fg and foe), in this cycle and generates a stable signal V, the sign of which corresponds to the sign of the phase mismatch of these pulses or, if a pulse fg is received, outputs the signal V 0. Integrator 5 integrates a stable signal V, if V О and remembers the previously accumulated value of the integral, if V is 0. Delay element 6 provides a pulse delay for a time proportional to the current value of the integral Vn (delayed pulse is indicated by fja).

The phase discriminator 7, via amplifier 8, supplies power to the motor 9 at the time the IPZ pulse arrives at the discriminator. The process then repeats.

If, for example, the frequency pulses fc lags in phase from the frequency pulses f, and the time interval between these pulses exceeds -c, the relay element 4 supplies the integrator 5 with a stable negative signal (V 0), the integrator 5 smoothly reduces the pulse delay fg into the delay element 6. The phase change of the reference signal of the slave drive obviously leads to a smooth phase change of the foe signal, from the feedback sensor in the direction of decreasing the phase mismatch of the pulses, and this process continues until the gap between

impulses 1 and ioe. will not become less than r, after which the relay element 4 supplies the integrator 5 with a zero signal (V 0). The phase of the pulses fgs and foe in this case is fixed and the synchronous rotation of the motors 1 and 9 is achieved with an error determined by the ratio.

, (2)

where I is the angular velocity of rotation of the engines of the system.

Obviously, the appropriate choice of r can always ensure the fulfillment of inequality.

D fa d pi (3)

Thus, the use of the method makes it possible to increase the accuracy of the phasing of electric drives with phase discriminators without increasing the number of marks of the rotation speed sensors of the phased motors.

Claims (2)

1. Trakhtenberg RM. Stabilization of electric motor speed, Journal of Automation and Instrument Making, Kiev, 1962, No. 4, p. 21-25. 2. Trakhtenberg R.M. Discrete high-precision electric drives for textile -induration. “Avto.matizirovanny electric drive in the national household, Proceedings of the All-Union conference on automated electric drive, volume 4, Electric drive in the chemical, paper and light industries and agriculture. M., “Energie, 1971, p. 267-268.