Development of backward simulator based on dynamic programming for the multiple power sources of series hybrid electric vehicle

There are many studies about how to control and distribute the power sources of hybrid electric vehicles which consists of engine and battery. However studies about to control the three power sources of HEV system is not studied enough. In this study a backward simulator which could calculate the optimal distribution of multiple power sources, engine, battery and ultra capacitor, of series HEV was developed. The method of the backward simulator to calculate the optimal solution is based on the dynamic programming which is one of the optimization theories. For the verification and the comparison of the backward simulator two series HEV system of which one only consists of engine and battery of which the other one consists of engine, battery and ultra capacitor were applied to the backward simulator. As a result, the latter system which includes ultra capacitor is more efficient than the other one because of low resistance of ultra capacitor. However it spent tremendous time to calculate the system of three power sources because each two state variables and two control variables make simulation much more complicated and plenty of calculation quantity. To develop the simulator more reasonably it needs further study how to decrease the calculation amount of simulation.