Wide input/output control method for a bidirectional series capacitor high-gain DC–DC converter

摘要

Series capacitor converter is a kind of high-gain DC-DC converter based on interleaving and paralleling technics. Currently for the n-phase bidirectional series capacitor high-gain DC-DC converter, it still has disadvantages of narrow duty cycle range and narrow input / output voltage range, which make the converter just suitable for the duty cycle range only from (n-1)/n to 1 in the boost mode, and from 0 to 1/n in the buck mode. To achieve wide input / output voltage range and high voltage gain, a novel control method by widening the duty cycle range from 0 to 1 is proposed in this paper. Meanwhile, the automatic current sharing of inductors can also be achieved with the proposed control method. The operating principle, voltage gain, as well as current distribution of inductors with the duty cycle range from 0 to 1 are then analysed and calculated comprehensively. Wide input / output voltage range, corresponding working duty cycle range, voltage gain and current distribution feature are verified by a three-phase bidirectional series capacitor high-gain DC-DC converter prototype experiment.