A MICROPROCESSOR-BASED DC DRIVE CONTROL SCHEME USING PREDICTIVE SYNCHRONIZATION

With the advent of faster microprocessors, refinements in the control systems for thyristor-fed dc drives have become possible. In such driv es, the problem of detecting the true zero crossings of the input volt age, when the mains supply is contaminated with noise spikes, is quite important. A new approach for this problem, based on the predictive s ynchronization concept, is presented in this paper. The algorithm pres ented also covers the 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 also presented in this paper.