Series parallel resonant converter for Electrical Dischage Machining power supply

Traditional EDM power supplies convert the energy at low frequency, directly from the utility line and they are able to deal with a wide spectrum of output power. The EDM power supply must achieve high voltage to generate the spark and large current to maintain the ion column. To achieve this, large and heavy transformers and inductances are required. Resonant converters are desirable for power conversion due to their comparatively smaller size and lower power losses resulting from high-frequency operation and inherent soft switching. Among all the topologies of the resonant converters, the series-parallel resonant converter (SPRC) is known to have the combined merits of the series resonant converter and parallel resonant converter. The converter can regulate the output voltage at a constant switching frequency even for a change in load resistance from full load resistance to infinity while maintaining good part load efficiency. The purpose of this project is to design a closed loop controller for the phase-controlled series parallel resonant converter (PC SPRC). The open loop analysis and closed loop control has been provided in this paper.