This paper analyzes the voltage overshoot phenomenon on auxiliary switches in Auxiliary Resonant Commutated Pole inverters and proposes a saturable inductor-based method to suppress the voltage overshoot. The basic operating principle of the ARCP inverter was explained, and a circuit model was presented to analyze the cause of auxiliary switches’ voltage overshoot. It was found that the high di/dt during the diode reverse recovery current extinguishing process induces unwanted voltage and both the resonant inductor (Lr) and parasitic inductances, and this is the main contribution to the excessive voltage. Several possible solutions are discussed, and a proper method is proposed. One of the proposed methods replaces the fixed-resonant inductor with a saturable-core inductor presenting high inductance at near zero current. The core’s selective-high-inductance reduces the reverse recovery current and the di/dt, and its high-frequency resistance help suppress the overvoltage and mitigate the oscillation. Several ARCP inverter single-phase prototypes have been developed to observe and understand the overvoltage phenomenon and the effectiveness of the mitigation method.
