Hybrid Excavator Power System Controller Design Based on Fuzzy Control

Controller of hybrid excavator power system was designed with control target was to improve diesel engine fuel efficiency and decrease shaft rotate speed fluctuation. Controller input parameters were set as hydraulic pump required torque, hydraulic pump rotate speed and battery SOC. Controller output parameters were set as diesel engine output torque and motor torque. Diesel engine output torque was obtained according to its load characteristic curves. Control method of diesel engine throttle based on Fuzzy control was proposed. Power system working pattern switch rules were introduced. Simulation model of controller performance based on MATLAB was established. Controller working performance simulations in mining condition and formation condition were simulated. Simulation results show that hydraulic pump required torque is provided by diesel engine and motor in mining condition. Power system required torque is provided by motor in formation condition. Battery SOC curve is changed according to designed control rules. Diesel engine shaft rotate speed is almost constant during the whole working process. Diesel engine fuel consumption rate is constant in mining condition and is almost zero in formation condition.