Bidirectional Wide Voltage Range Series-Parallel Resonant Buck-Boost DC-DC Converter

This paper explores the possibility for the buck-boost series-parallel resonant current-source converter (SPR-CSC) to be adopted for bidirectional operation. Due to the presence of a parallel capacitor, the conventional modulation approaches cannot be directly applied for reverse operation mode. To address this, two new modulation techniques are developed that create zero voltage switching (ZVS) conditions and avoid the capacitive loading of the transistors during turn-on. The modulations allow the converter to operate in both buck and boost modes and additionally take advantage of voltage range extension using a reconfigurable full- / half-bridge circuit. The operational modes are described and verified using a 3.3 kW model of the converter that interfaces 350 VDC and 200 ... 800 VDC sources. An analysis of stresses on converter components is given to assess the impact and additional requirements introduced when adopting the topology to bidirectional operation.