Research on the ultracapacitor/battery hybrid system

The ultracapacitor/battery hybrid system makes the best of the characteristics of high energy density of battery and long cycle life of ultracapacitor. The mathematical model of ultracapacitor/battery hybrid system was set up, and the characters of it such as peak power enhancement were studied and the correlative factors were analyzed in this paper. Ultracapacitor and battery are connected in parallel by a bi-directional buck-boost converter. Model the ultracapacitor/battery hybrid system under MATLAB 7 and use a double loop PWM to control. The result shows that battery and ultracapacitor could work in optimizing discharge condition when the load power is pulsating. The bi-directional buck-boost converter has better performance and practicability.