Design and validation of SVPWM algorithm for thermal protection of T-type three-level inverters

This paper investigates the design and validation of a new space vector pulse width modulation (SVPWM) algorithm for thermal protection of T-type three-level inverters. Thermal overheating is the main cause of shortened-lifetime and open-circuit faults of power devices. Power devices are subjected to thermal overheating due to degradation of power devices due to continuous overloading and power cycling, and degradation and faults in cooling systems. When a thermal overheating is detected in one of the switching devices, the proposed algorithm is applied to protect the thermally-overheated switch from being short/open-circuited and hence preventing the total system from malfunction. The lifetime and the reliability of the inverter have been enhanced considerably by a simple modification of the conventional SVPWM algorithm and without adding any additional hardware or complex calculations. In addition to that, the proposed algorithm does not deteriorate the inverter's output current. The proposed thermal protection SVPWM algorithm has been designed, simulated, and experimentally validated at different operating conditions.