Non-invasive IGBT power loss model identification in two-level voltage source converters

This paper proposes a method for the identification of the electrical and thermal model of low power voltage source converters (VSCs) under nominal operating conditions. The identified model of the insulated-gate bipolar transistors (IGBTs) and heat-sink thermal resistance can then be used with existing power loss estimation methods. Only steady state measurements are performed on the assembled converter, without the need of a complicated test bench. The method is validated with three two-level three-phase VSCs in two test locations. Estimated power loss with the obtained model using recorded load current and one transistor command signal is compared with calorimetric measurements with good results.