Optimization of Energy Saving and Fuel-Cell Durability for Range-Extended Electric Vehicle

Abstract

For a fuel cell range-extended electric vehicle (FC-REEV), the fuel cell system can work at a fixed output power point, and it has high durability. However, the differences in output power and start–stop threshold can lead to a significant difference in energy loss and degradation of power sources. Based on the thermostat control strategy (TCS), the state of charge (SOC) of the battery is stabilized within a reasonable range. To obtain the lowest hydrogen consumption rate, the vehicle’s fuel economy is considered in the evaluation function. The artificial bee colony (ABC) optimization algorithm is then used to increase the driving range, and the conventional ABC-TCS (CABC-TCS) is proposed. However, the CABC-TCS leads to many start–stop times for fuel cells. To enhance the durability of the fuel cells, a penalty factor was added to the evaluation function, and a novel optimized ABC-TCS (OABC-TCS) is proposed. Different strategies were tested under federal test procedure (FTP)-72 and worldwide light-duty test procedure (WLTC) driving cycles. The results show that, compared with TCS, the optimized driving range of OABC-TCS in FTP-72 and WLTC conditions increased almost 10.59% and 10.3%. Compared with CABC-TCS, the start–stop times of OABC-TCS in FTP-72 and WLTC conditions decreased by 27.55 and 46.47 times/h, respectively.