Abstract:

The present research proposes two different power sharing control strategies for a suitably sized battery-UC HESS. The first one which is called as speed related control (SRC) uses an empirical relationship based on the knowledge of the speed and the passenger load on the vehicle. The second one which is labeled as fuzzy based control (FBC) uses fuzzy logic control, based on the actual state of charge of UC and the converter output (load) current. Both the methods ensured that the UC SoC is maintained within the desired limits for both modified and old Indian urban driving cycles. The maximum value of the battery current is limited and the peak power requirement during transient condition is handled by the UC. Also the regenerated power is fully absorbed by the UC. Approximately 5% improvement in the range is expected in city drive due to the possible improved regeneration. The simulation results show that the performance of FBC is better in limiting and leveling the battery current and hence improving the battery cycle life. The battery cycle life improvement estimated for SRC is 49.5% while that for FBC is 56%.