A Hybrid Dc Device To Protect Electrical Vehicles Against Overcurrent

Electric vehicles are developing quickly across the world. In an electric vehicle, the high voltage-protection apparatus is a DC contactor in series with an electric fuse. However, two to five times overload current is difficult to interrupt for both apparatuses. A hybrid DC device composed of a mechanical switch, a power semiconductor switch, and an electric fuse can solve this problem. The objective of this article is to determine the interruption and current commutation characteristics of the hybrid DC device based on simulation. The model of the three parts is built in Simulink/MATLAB separately. The current commutation characteristics are investigated based on the model. The model is experimentally validated. The simulation results show that the current commutation time decreases when the loop inductance and resistance decrease, or when the arc voltage increases. The model of the hybrid DC device fits well with the experimental results.