Influence of the junction capacitance of the secondary rectifier diodes on output characteristics in multi-resonant converters

Multi-resonant converters like the CLLLC topology are known for their outstanding efficiency and high power density. Little information has however been published about the influences of secondary side diode junction capacitances on the output characteristics of the resonant converter. This paper presents a detailed analysis of these influences in the inductive working range and reviews practical design considerations of the converter. Therefore, experimental results of an inductive power transfer system, using a CLLLC resonant topology, are compared to theoretical time domain solution, showing significant effects of different semiconductor materials and devices on output power. These effects will be discussed and explained in detail by using measured key waveforms.