Power management of passive multi-source hybrid electric vehicle

A multi-source hybrid electric vehicle which contains a gasoline-generator set (genset), a lead acid battery pack and an ultracapacitor is designed and implemented based on a commercial all terrain utility type of electric vehicle. In order to study the natural power flow on the 48V DC Bus, DC-DC converters are omitted between lead acid battery and the DC Bus as well as between ultracapacitor and the DC Bus. Both lead acid battery and ultracapacitor are connected to the DC Bus directly. Simulation model is built and used to obtain the power flow rules, which will be useful for passive multi-source hybrid electric vehicle power management. Experiments are implemented with designed passive multi-source hybrid electric vehicle to validate the simulation model and power flow rules. Based on the power flow rules, dynamic programming is used to optimize the power management control strategy. By controlling the on and off of the genset, dynamic programming can obtain global optimization for the whole trip when the whole driving cycle is known at the beginning of the trip. Simulation and experimental results indicate that using dynamic programming control method can save as much as 12.6% of gasoline.