Turn-off switching loss model and analysis of IGBT under different switching operation modes

Due to its high voltage and current ratings, the IGBT has become more attractive in the high voltage and high current applications than the MOSFET. However, its slow turn-off characteristics, high turn-off losses make it difficult to operate at relatively high switching frequency. Turn-off switching loss model and analysis of IGBT under the hard switching, emitter-open and mixed parallel operations were presented in this paper. Examples of full bridge DC-DC converters using IGBT and MOSFET are analyzed to show that the turn-off switching loss can be significantly reduced if soft turn-off techniques are employed when proper gate controls of IGBTs and MOSFETs are used. It can be seen that these techniques are very attractive in the full bridge type converters for high power applications. The 75 kHz, 100 Watts prototype converter was implemented to verify our theoretical analysis.