Multi-Level Contactless Zero-Voltage Switching Rectifier as a Pre-Regulator in a DC Laboratory Power Supply

The paper describes usual solutions of preregulators in laboratory power supplies and a completely new method of voltage pre-regulation in laboratory power supplies. It is a multi-level rectifier in which it is possible to switch output voltage in steps. This decreases power loss of the output transistor. Contactless switching at zero voltage is ensured by triacs, which makes it possible to ensure high reliability and low electromagnetic interference even during transients events. The control circuits are also described in the paper and measurements on the realized sample are presented.