Abstract: According to the vehicle performance requirements and driving cycle, the original single
power system of a plug-in hybrid electric vehicle is transformed into hybrid power system which is
consist of battery and super-capacitor that are matched by decoupling the requirement of energy and
power. The power allocation strategy of hybrid power is built in Matlab/simulink. The simulation
results show that the hybrid power system can reduce the battery charge cycles, effectively avoid the
impact of battery from the large current and can give full play to high power characteristics of
super-capacitor. Comparing with the former, the fuel economy and pure electric mileage are increased
by 3.4% and 1.3%.

Key words: battery, super-capacitor, hybrid power system, plug-in hybrid electric vehicle