This thesis presents a method for junction temperature estimation using the mathematical thermal modeling in a two-level IGBT inverter for motor drives. A power conversion system (PCS) is made up of several components, with IGBT switches being the key components determining the reliability of the PCS. One of the issues with regard to a PCS is improving its reliability, the failure of IGBTs is primarily caused by variations in the junction temperature. The thermal behavior of the IGBT switches must be described in order to forecast the PCS lifetime. The profile of load current is specific to the application, and the thermal behavior is dependent on the current that flows to the IGBT. The switch module is usually encapsulated. Therefore, an additional manufacturing process is necessary for measuring the junction temperature. The presented mathematical model-based temperature estimating method does not require an additional process for temperature measurement. An experiment is conducted using a diode-doped custom module to determine the thermal behavior of the IGBT for 11-kW IPMSM (interior permanent magnet synchronous motor) drives. The effectiveness of the presented estimation method is verified by the simulation and experimental results.
