Heuristics EMS for HESS of Electric Vehicle to Extended Battery Operation Using Rate Limiter

Energy management strategy (EMS) works as an exchange where the allotment of power is decided between different sources in the hybrid energy storage system (HESS). While designing EMS, the performance indicators of the HESS, like voltage and state-of-charge of sources, dc-link voltage, and battery power delivering rate, should be considered for extended battery operation to enhance the vehicle performance effectively. The rate limiter restricts the rate of power flow from the battery and thus protects the battery from a high current rate, ensuring extended operation. This paper proposes a modified topology and EMS for controlling performance indicators with rate limiter operation. The HESS consists of one battery and two ultracapacitor banks. The auxiliary ultracapacitor is used to counter the effect of the rate limiter on vehicle dynamics. The auxiliary battery with reserve capacity is considered to run the vehicle in an emergency condition. This auxiliary battery storage is integrated with renewable (solar) as a standby provision. The proposed schemes are capable of providing supervisory control over performance indicators. It is evident from the simulation results that the proposed scheme saves 11.79% of battery energy for a designed load torque as compared with a battery-alone electric vehicle.