This paper presents two new circuit topologies of dc busline series active snubber assisted soft switching PWM full-bridge dc-dc power converter acceptable for either utility ac 200V-rms or ac 400V-rms Input voltage source. Proposed power converters are composed of a typical voltage source full-bridge high frequency PWM Inverter using dc busline side series switching devices with the aid of a parallel capacitive lossless snubber. All the active power switches In the full-bridge arms and dc busline 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 for used IGBTs can be actually realized more than about 20 kHz. It Is proved that the more the switching frequency of full-bridge Inverter Increases, the more soft switching PWM dc-dc power converter with a high frequency transformer link has remarkable advantages for Its power conversion efficiency and power density as compared with the conventional hard switching PWM Inverter type dc-dc converter. The effectiveness of this new converter topology Is proved for low voltage and large current dc-dc power supplies as arc welding machine from a practical point of view.