Ultra-capacitor control strategy of EV with energy hybridization

The application of ultra-capacitor used in multi-energy battery system on EV is introduced in this paper, and an energy management strategy of ultra-capacitor is proposed. With this strategy, the state of charge (SOC) of the ultra-capacitor should be kept at a proper level according to different speeds of the vehicle. Before accelerating, the SOC should be high enough to supply an extra large current for batteries. Vise versa, before braking, the SOC of the ultra-capacitor should be empty out for large regenerated energy. The model of this control strategy based on multi-energy EV is established, and simulated with use of the MATLAB/Simulink. Then the characteristics of maximum output power and efficiency of the ultracapacitor is studied. Based on these works, reliable protection and better performance of the multi-energy battery system become possible.