A Novel Type DC Rail-Series Switch and Parallel Capacitor Snubber-Assisted Soft Switching PWM DC-DC Converter with High Frequency Transformer

This paper presents a new circuit topology of DC bus line switch-assisted full-bridge soft switching PWM inverter type DC-DC converter. The proposed power converter is composed of typical voltage source H full-bridge high frequency PWM inverter with a high frequency transformer link in addition to a single DC bus line side power semiconductor switching device for PWM control scheme and a capacitive lossless snubber. All the active power switches in the full-bridge arms and DC bus line can achieve ZCS turn-on and ZVS turn-off commutation operation and consequently the total turn-off switching losses can be significantly reduced. As a result, a high switching frequency of used IGBTs can be actually selected more than about 10 kHz. The effectiveness of this new converter topology is proved for low voltage and large current DC-DC power supplies such as arc welders and communication-related power supplies from a practical point of view