The active-clamped soft-switching inverter can realize the soft-switching of power devices,which is conducive to improving the power density and dynamic performance of the inverter.However,when overcurrent occurs,if the conventional cycle-by-cycle(CBC)current limit strategy(i.e.,a strategy under which power devices will be blocked once overcurrent occurs)is adopted,the DC bus current will change its direction from flowing to the inverter bridge to flowing to the DC side.Due to the existence of a resonant inductor,both the DC bus current and the current flowing through the resonant inductor flow through the auxiliary switch,so there is high current stress on the auxiliary switch.In this paper,an improved CBC current limit strategy is proposed.By changing the switching state of the inverter bridge after the CBC current limit strategy is triggered,the DC bus current flowing to the DC side is reduced,thus significantly suppressing the current stress.In addition,the protection strategy was verified by an experiment of 3 kW active-clamped soft-switching inverter.
维普
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