DIGITAL CONTROLLER FOR THYRISTORS

摘要

Apparatus for digitally controlling a thyristor includes a pulse frequency modulator having a resettable integrator that is coupled to an alternating current power source which supplies the thyristor. A predetermined number of integrated signals are produced by the integrator in response to each half-cycle of the alternating current waveform. The integrated signals are processed by a comparator circuit relative to a reference voltage to produce a corresponding pulse train output having an inverse-cosine time separation between pulses. Means are provided to synchronize the pulse train with the power source by introducing compensating changes in the reference voltage that correspond to the time difference between the end of each positive half-cycle of the alternating current waveform and the time taken to generate the predetermined number of pulses. A counter produces a binary output signal corresponding to the pulse train which is compared with input data from a digital computer. A digital comparator generates a signal to enable a gate that couples the pulse train to a thyristor control input when the binary output signal and the computer data are in numerical coincidence.