Single-capacitor phase-controlled series resonant converter

A new phase-controlled series resonant, DC/DC converter is described, analyzed, and experimentally verified. The circuit comprises a phase-controlled inverter and a Class D current-driven rectifier. The phase-controlled inverter consists of two switching legs, two resonant inductors, and a single resonant capacitor connected in series with an AC load. The phase shift between the voltages that drive the MOSFETs is varied to control the AC current of the inverter and thereby regulate the DC output voltage of the converter. A frequency-domain analysis is used to derive basic equations which govern the circuit operation. An important advantage of the converter is that the operating frequency can be maintained constant. For operation at a switching frequency greater than 1.15 resonant frequency, the load of each switching leg is inductive. The proposed converter has an excellent full-load and part-load efficiency. An experimental prototype of the converter with a center-tapped rectifier was built and extensively tested at an output power of 78 W and a switching frequency of 200 kHz. The theoretical and experimental results were in good agreement