Design Considerations to Increase Power Density in Welding Machines Converters Using TRENCHSTOP 5 IGBT

The demand for portable low cost welding machines, especially in developing countries, is increasing. In the Manual Metal Arc (MMA) and Tungsten Inert Gas (TIG) types, in power range from 1,5kW up to 5kW, discrete IGBTs and MOSFETs are broadly used. Mostly, these machines use hard switching current mode PWM controls and simple topologies, like Two Transistors Forward (TTF), Half Bridge (HB) and Full Bridge (FB). For these configurations, high frequency is seen as one of the most important design trends to improve performance and to reduce cost at system level. Infineon's TRENCHSTOP(TM) 5 IGBT technology is the most promising candidate fully capable to accomplish these technical requirements [1]. These IGBTs can be selected to improve performances of the previous generation IGBTs, while operating at higher switching frequency, or to directly replace conventional High Voltage MOSFETs keeping present switching frequency up to 100 kHz in proper layouts. This paper describes the potential of the TRENCHSTOP(TM) 5 technology when used in an optimized converter design. Different demonstrator boards have been created to proof benefits which arise from this technology.