A microprocessor-based DC drive control scheme using predictive synchronization

With the advent of fast microprocessors, refinements in the control systems for thyristor-fed DC drives have become possible. In such drives, the problem of detecting the true zero crossings of the input voltage, when the main supply is contaminated with noise spikes, is quite important. A new approach for this problem, based on the predictive synchronization concept, is presented. The algorithm also covers other aspects, like generation of firing pulses and closed-loop calculations for the drive control. The microcomputer-based system has been tested on a separately excited DC motor, and the test results are presented