Thermal Stress Oriented Dispatch Strategy for Paralleled Grid-Connected Converters in Electric Vehicle Charging Stations

The severe thermal stress is justified to be one major failure cause in power semiconductor devices. Most of the previous thermal stress reduction methods only scope on the local controller level for the individual converter. In the proposed method, a centralized system level strategy is designed to deal with the varying charging profiles in the electric vehicle charging station, where the proposed dispatch algorithm makes full use of the local control level thermal stress reduction methods, including the reactive power injection and the switching frequency variation, to adjust the power loss and reshape the thermal profiles for multiple grid-connected converters. The proposed thermal stress oriented dispatch (TSOD) strategy is described in this paper and its superior performance on the junction temperature profiles is validated through a real-time model-in-the-loop testing and a digital twin experimental prototype.