Digitally Controlled Thyristor Current Source

A digitally controlled current source, based on a 6-pulse thyristor bridge is described. When part of a larger system, the source is amenable to direct microprocessor control. Salient aspects of the design described here are a new method for zero voltage detection and the configuration and analysis of a digital proportional-integral (PI) controller. The paper gives the design procedure as well as the experimental results obtained on the actual current source.