Thermal management implementation method for IGBT modules of inverters based on junction temperature estimation

Insulated gate bipolar transistors (IGBTs) are widely used in grid-connected renewable energy generation. Junction temperature fluctuation is an important factor affecting the operating lifetime of IGBT modules. Many active thermal management methods for suppressing junction temperature fluctuation exist, but research on the implementation of thermal management in converters is limited. Junction temperature extraction is the basis of implementing thermal management. In this study, a thermal network model method and a temperature-sensitive electrical parameter (TSEP) method for junction temperature estimation are analyzed first. Aiming to limit the maximum junction temperature of IGBTs, a thermal management method is proposed by changing switching frequency. Then, for a three-phase two-level inverter, the effectiveness of the proposed thermal management method is analyzed by offline simulation based on the thermal network model method. Lastly, the IGBT junction temperature in the inverter is estimated online by using the TSEP method and the feasibility of the thermal management implementation method is verified on an experimental platform.