Analysis of High voltage fuse failures due to reverse surge currents flow in the Power distribution unit of Electric vehicles

Commercial Electric vehicles are revolutionizing the transportation industries with zero emission, lower noise level and increased efficiency. But, High voltage (HV) fuse failures due to reverse surge currents in the Power distribution unit (PDU) hampers the field operation and raise the sensitive safety concerns. This paper embarks on an in-depth exploration of the Reverse surge current flows from the DC-DC converter and Auxiliary (AUX) inverters high voltage input side to Traction system high voltage input point. Failures of HV fuses can lead to the unintentional shutdown of the e-compressor system and steering motor system while operating the EV, which raises critical safety concerns. If the steering motor fails, the bus will lose power steering assistance, making the steering wheel much harder to turn. If the e-compressor fails, it could result in loss of braking assist. This could make it difficult to stop the vehicle, especially in an emergency situation or when driving at high speeds. Test results are backed up by multiple field vehicle trials on the different terrains for thousands of kilometers. Testing data has been captured with the high frequency data acquisition system along with high current high voltage probes. Detailed root cause analysis of high surge currents flow has been carried out with current-voltage waveforms. The mitigation of surge current flows in the PDU has been carried out with implementation of Various Power diode configurations and implemented effective vehicle system protection. By following the approach described in this paper, significant failures of high voltage components prevented and number of the vehicle breakdowns reduced near to zero.