双向多电平LCL谐振变换器全范围软开关的混合调制策略

The multilevel hybrid modulation can effectively reduce the circulating current in bidirectional LCL resonant converters under light load conditions. The conventional asym-metric multilevel modulation struggles to maintain soft switching during both forward and reverse power transfer. Additionally, current calculations based on fundamental harmonic analysis (FHA) lead to significant deviations in the instantaneous current, especially under light load conditions and with multilevel modulation, affecting the accuracy of ZVS characteristic analysis. To address these issues, this paper proposes a hybrid modulation strategy based on the multilevel bridge structure. This approach broadens the soft switching range during reverse power transfer by selecting appropriate converter's switching logic. By incorpo-rating phase shift angles, the proposed hybrid modulation ensures soft switching even under light load conditions. To obtain more accurate the instantaneous current values of the switches, a time-domain signal superposition analysis method is used instead of FHA. Finally, a 1.5-kW experimental prototype has been developed to validate the effectiveness of the hybrid modulation strategy and the accuracy of the time-domain analysis method.