Derivation of Resonant Period for Soft Switching Considering Nonlinear Characteristics of Output Capacitance in Switching Device

Abstract

Many soft switching techniques utilize a resonance between an inductor and parasitic output capacitors of switching devices. However, output capacitance has nonlinear characteristics, which obscures the resonant period for soft switching. In this paper, a new method is proposed to derive the resonant period by considering nonlinear characteristics of the output capacitance. The method can be applied to a bridge-type converter which utilizes resonance for soft switching. Other parasitic capacitances which affect the resonant period, are also considered. To verify the proposed method, simulations and experiments were performed with a 3-kVA prototype half bridge auxiliary resonant commutated pole inverter.