The design of welder power supplies incorporating self-oscillating high-frequency transformer inverters

Different aspects of the design of power electronic inverters for low mass welding applications are described. High frequency (15 kHz) is used at power levels up to 10 kW, and emphasis is placed on the minimisation of losses in the ferrite-core transformer and power switches to obtain an efficient and compact system. Attention is given to a very simple low-loss turn-off snubber ideally suited for the application. Two welding systems which were developed and tested are described. These were a 220 V single-phase and a 380 V 3-phase unit. Design considerations and practical results are also presented. It is concluded that such inverters have great potential for application in this field.