SINGLE-CAPACITOR PHASE-CONTROLLED SERIES RESONANT CONVERTER

A new phase-controlled series resonant dc/dc converter is described, a nalyzed, and experimentally verified. The circuit comprises a phase-co ntrolled inverter and a Class D current-driven rectifier. The phase-co ntrolled inverter consists of two switching legs, two resonant inducto rs, and a single resonant capacitor connected in series with an ac loa d. The phase shift between the voltages that drive the MOSFET's is var ied to control the ac current of the inverter and thereby regulate the dc output voltage of the converter. A frequency-domain analysis is us ed to derive basic equations which govern the circuit operation. An im portant advantage of the converter is that the operating frequency can be maintained constant. For operation at a switching frequency greate r than 1.15 resonant frequency, the load of each switching leg is indu ctive. 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 o f 78 W and a switching frequency of 200 kHz. The theoretical and exper imental results were in good agreement.