Power losses of IGBTs in an inverter prototype for high frequency inductive heating applications

An IGBT prototype inverter has been constructed for high frequency induction heating applications. This inverter has been installed and tested successfully in an experimental industrial platform. The inverter unit consists of only four high power IGBT modules, which build a full bridge inverter unit. Operating under almost zero current conditions, the IGBTs of the inverter unit deliver an output power of more than 100 kW at a switching frequency of 100 kHz. This high power frequency product represents a significant challenge for today's semiconductor technology. For the inductive heating application in modern industries, several MWs are required. Therefore, the maximum rating of one inverter unit is of particular interest to reduce the number of inverters connected in parallel. The maximum output power rating of one inverter unit is mainly limited by the high power IGBT module losses and the cooling capability of the heat sink. In this paper, the IGBT prototype inverter and the measurement methods to determine the IGBT power losses of the high frequency high power inverter are presented.