Modular bidirectional DC-DC converter for hybrid/electric vehicles with variable-frequency interleaved soft-switching

This paper presents a modular soft-switching bidirectional DC/DC converter for hybrid/electric vehicles. The converter operates in a variable-frequency quasi-square-wave (QSW) mode, which enables high efficiency, high switching frequency, and high power-density. The converter presented utilizes a new variable frequency interleaving approach which allows for each module to operate in an interleaved position while allowing for tolerance in inductance and snubber capacitor values. The variable frequency interleaved operation paired with high-efficiency soft-switching, a high-density inductor design, and optimal packaging results in a very high power-density converter. The 25 kW per module prototype converter exhibited power density greater than 8 kW/L, and peak efficiency over 97%, while operating with 100degC coolant.