A Low-Stress Zero-Current Switching Technique for Power Converters

Huge voltage spikes on auxiliary switches is a common issue for most of the existing zero-current switching (ZCS) pulsewidth-modulated (PWM) converters. The reason for the spike lies in the parasitic resonance between the resonant inductance and the stray output capacitance C oss of the auxiliary switch, which does not have the negative impact in zero-voltage switching (ZVS) converters. This paper proposes a low-stress ZCS technique to eliminate the negative consequence of the C oss in ZCS PWM converters. All the power devices, including the auxiliary switch, show low voltage stresses and ZCS. The auxiliary cell of the low-stress ZCS technique introduced a clamping diode to realize the low-voltage stress for the power devices. The low-stress ZCS buck converter is taken as an example to explain both the low-stress and ZCS characteristics. A 2-kW hardware prototype is developed. The simulation and experiment results both validate the effectiveness of the proposed low-stress ZCS technique.