A New Multi-Phase DC-DC Converter with Interleaved TCM Si Phases and High-Frequency Auxiliary SiC Phase

A new hybrid Si/SiC multi-phase interleaved dc-dc converter is proposed in this article, which consists of two interleaved large-capacity Si phases and an auxiliary small-capacity SiC phase. The Si phases operate in Triangle Current Mode (TCM) to process the base power with Zero Voltage Switching (ZVS) capability and lower switching frequency, obtaining significantly reduced switching losses. While the auxiliary SiC phase handles a small part of the total power, and its switching frequency is high and rated current is small, which is mainly used to compensate the current ripple of the Si phases to obtain superior current and voltage waveforms and fixed frequency spectrum. In order to coordinate the three phases with different current modes and switching frequencies, a hybrid-frequency interleaved control strategy is proposed. Finally, we present a 3.1 kW mixed mode Si/SiC multi-phase interleaved dc-dc converter, it exhibits a peak efficiency of 96.8% and a 120kHz effective frequency.