Characteristics of Interleave Operation of Isolated dc-dc Converter with class Phi-2 inverter

The resonant power converter has a lot of attention because switching losses are small by a soft-switching topology even in the high-frequency region beyond over 1 MHz. The class Phi-2 inverter, which is one of the resonant power converters, is able to operate as an inverter with only one switching device. However, the operating area of the class Phi-2 inverter is limited by load conditions because the drain-source voltage waveform is effected by load resistance. Thus, the class Phi-2 inverter is able to operate only under nearly designed load conditions, and not to operate under various load applications. Therefore, extension of the operating area of the class Phi-2 inverter is desired. In this paper, the interleaving operation of the isolated dc-dc converter with the class Phi-2 inverter, which is required for increasing the output power and applicable range of the load, is investigated. Simulation and experiment of the converter with interleave configuration are conducted at the switching frequency of 13.56 MHz. From simulation and experiment results, it was confirmed that the interleave configuration is effective to extend the operating area of the converter, and increase the output power. Moreover, the output power is able to be controlled by applying ON/OFF control from the circuit under various load conditions.