基于GaN器件的双向CLLC谐振变换器分析与设计

Analysis and Design of Bidirectional CLLC Resonant Converter Based on GaN Devices

GaN器件具有开关速度快、导通电阻低、寄生参数小和反向恢复损耗低等优良特性,相比其他器件更有利于实现双向CLLC谐振变换器的高频率和高效率。文中基于GaN器件的特点,利用戴维南等效定理对双向CLLC谐振变换器的谐振频率进行了分析求解,并根据开关管寄生电容的充放电特性来改善软开关的实现条件,最终研制了一种基于GaN器件的双向CLLC谐振变换器。文中还搭建了额定功率为400 W的双向CLLC谐振变换器实验样机,实现了全负载范围内逆变侧的零电压开通和特定负载范围内整流侧的零电流关断,在正向模式下的最高效率可达97.02%,反向模式下的最高效率可达95.96%,最大工作频率达548 kHz,具有高频率和高效率的特点,从而验证了所分析与设计的变换器的正确性和有效性。

GaN device has the advantages of fast switching speed,low on-off resistance,small parasitic parameters and low reverse recovery loss.As compared with other devices,it is more conducive to realizing the high frequency and high efficiency of bidirectional CLLC resonant converter.In this study,based on the characteristics of GaN devices,the resonance frequency of the bidirectional CLLC resonant converter was analyzed and calculated by using Thevenin equivalent theorem,and the condition to realize the soft switch was improved according to the charging and discharging characteristics of parasitic capacitance of switch tube.Finally,a bidirectional CLLC resonant converter based on GaN device was developed.An experimental prototype of bidirectional CLLC resonant converter with a rated power of 400 W was built to achieve zero-voltage turn-on(ZVS)on the inverter side in all load range and zero-current turn-off(ZCS)on the rectifier side in a specific load range.Its maximum efficiency can reach to 97.02%in the forward mode and 95.96%in the reverse mode,and its maximum operating frequency is 548 kHz.With features of high frequency and high efficiency,it verifies the correctness and effectiveness of the analyzed and designed converter.