Abstract

This article proposed a systematic approach for the control of three-phase bidirectional zero-voltage switching (ZVS) converters. Combining the adaptive hysteresis-band current control and turn-on delay modifications, ZVS conditions are realized in full line-cycle in all loading conditions like active power, reactive power, light load, and heavy load. The soft-switching resonant period is carefully analyzed, and the current band is designed accordingly, which minimized the additional conduction loss. Meanwhile, a zero-sequence voltage injection control is included in the approach, which compensates the voltage gain by 15% and narrows down the switching frequency variation range. The hardware design approach is also provided including the LCL filter design and a low-cost high-bandwidth high-accuracy current sensor design. A highly integrated 5-kW silicon carbide implemented three-phase ZVS converter prototype with printed circuit board integrated inductors and customized current sensors is designed. All the control is implemented in a single microcontroller unit, which achieves a high electromagnetic compatibility. The designed prototype achieves a total power density of 5.5 kW/L and a peak efficiency of 98.5%. All the analysis and the proposed control approach are experimentally verified on the designed prototype.