Modeling and Control Strategy of Parallel Hybrid System in Hydraulic Excavator

Abstract:

An analysis was made for a parallel hybrid excavator system with ultra capacitor and ISG (Integrated Starter Generator) as auxiliary electrical power source and characterized by motor-driven slewing mechanism.A dual-mode engine torque balancing control strategy was proposed,and the load condition and the SOC(state of charge) of ultra capacitor were employed as decision-making basis to adapt the engine operating point.At a specific point,the torque balancing control strategy was adopted instead of the traditional speed sensing control,thus the system could be more stable. ISG motor can balance the engine torque to make it work in high efficiency area.In addition,the slewing mechanism-driven motor can recycle Potential energy.A simulink simulation model of the parallel hybrid excavator system was set up.Results show that the control strategy is suitable for parallel hybrid power system excavator with significant energy saving.