Fuzzy Logic Based Energy Management Strategy for Series Hybrid Bulldozer

In order to improve the fuel economy of series hybrid bulldozer, the fuzzy energy management strategy is proposed. Firstly, the fuzzy logic controller is designed considering the state of charge of the super-capacitor in the current state. Then the inputs of the fuzzy controller are the required power and the state of charge of the super-capacitor. The outputs of the fuzzy controller are the target output power of the engine, the output power of the generator and the demand power of the super-capacitor. The results show that the strategy can not only distribute the output power of engine and discharge power of super-capacitor reasonably according to the demand power, but also maintain the SOC fluctuation in a reasonable range. It saves 13.3% fuel and improves the fuel economy of the whole machine. Therefore, this method is a feasible and effective energy management strategy.