Interleaved three-level bi-directional DC-DC converter and power flow control

Abstract

An interleaved three-level bi-directional DC-DC converter topology was proposed for high voltage, high power applications in the paper, which has simple structure and is suitable for single bus DC microgrid. The three-level inverter switching tubes voltage stress decrease to a half of the output of the high voltage side, while the interleaved parallel technology can reduce the inductance value, improve the converter dynamic performance and enlarge the converter capacity for applications in the energy storage units. The operating principle of the proposed interleaved three-level bi-directional DC-DC converter as well as the influence of the duty cycle on the operating state were analysed. The converter flying capacitor voltage control was presented, bidirectional power control method and the mode switching was studied in order to realize the bidirectional flow of power. Finally the experimental result is analysed to verified the correctness of the interleaved three-level bi-directional DC-DC converter and the effectiveness of the converter control strategy.