双向全桥LLC谐振变换器变频移相混合控制策略研究OA

Addressing the current issue of bidirectional full-bridge LLC resonant converters having a reverse operation voltage gain less than 1,and the problem that existing commonly used methods to increase the reverse gain result in significant losses,a control method to enhance the reverse operation voltage gain is proposed in this paper.This method integrates dual phase shift control based on variable frequency control,optimizing the traditional variable frequency-single phase shift control strategy.A simulation model of the converter's reverse operation is built in Matlab/Simulink.The results show that using variable frequency-dual phase shift hybrid control can achieve a reverse operation voltage gain greater than 1 without adding auxiliary inductance,enabling zero-voltage turn-on of the switch and zero-current turn-off of the secondary side,with good dynamic response performance.Under the same conditions of load and frequency,the backflow power generated by variable frequency-dual phase shift hybrid control and variable frequency-single phase shift control is 0.001 35 W and 0.042 50 W,respectively,with the former being only 3.2％of the latter.This hybrid control strategy is simple and easy to implement,enhances the voltage regulation capability of the converter during reverse operation,significantly reduces the backflow power generated by phase shift control,improves the converter's operating efficiency,reduces operating costs,and broadens its application scenarios.