A constant-frequency phase-controlled series-parallel resonant dc-dc converter is introduced, analyzed in the frequency domain, and experimentally verified. To obtain the dc-dc converter, two identical series-parallel resonant inverters are paralleled and The resulting phase-controlled resonant inverter is loaded by a voltage-driven rectifier. The converter can regulate the output voltage at a constant switching frequency in the range of load resistance from full-load resistance to infinity while maintaining good part-load efficiency. The efficiency of the converter is almost independent of the input voltage. For switching frequencies slightly above the resonant frequency, power switches are always inductively loaded, which is very advantageous if MOSFET’s are used as switches. Experimental results are given for the phase-controlled series-parallel resonant converter with a center-tapped rectifier at an output power of 52 W and a switching frequency of 127 kHz. The measured current imbalance between the two inverters was as low as 1.2:1.
ASJC Scopus subject areas
- Electrical and Electronic Engineering