Design and Control of Hybrid Electric Power System for a Hydraulically Actuated Excavator

In this paper, a prototype hybrid excavator that incorporates two electric motors and an ultra-capacitor module in a commercial diesel engine powered hydraulic excavator is presented. The features of the developed hybrid excavator include (1) electric propulsion of the swing system, (2) electric power assistance for the diesel engine and (3) energy regeneration using an ultra-capacitor module. By designing a suitable swing control and power management algorithm, the developed hybrid electric power system can significantly improve the fuel economy of the diesel powered hydraulic excavator, without any performance degradation or drivability deterioration.