Energy and Operation Characteristics of Electric Excavator With Innovative Hydraulic-Electric Dual Power Drive Boom System

In the existing electric excavators, the energy efficiency of the hydraulic system is less than 30% due to a large amount of throttling loss and waste of potential energy. In order to improve excavator energy efficiency, an electric excavator scheme using a hydraulic-electric dual-power drive boom system is proposed. A linear actuator, including electro-mechanical unit and hydraulic unit, was adopted in the boom system. The boom velocity is controlled by the electro-mechanical unit instead of hydraulic valve to reduce throttling loss. The non-rod chamber of the linear actuator is connected to a hydraulic accumulator to reutilize boom gravitational potential energy. In addition, when the boom and other devices are operated together, the throttling loss caused by load difference of multi-actuators can be reduced because the linear actuator can compensate for the pump pressure. The working principle, control strategy, and characteristics of the proposed electric excavator were analyzed through theory and experiments. The results show that the proposed system can reduce throttling loss and efficiently reutilize the boom gravitational potential energy. During boom lifting and lowering process, the reutilization rate of the boom gravitational potential energy is 67.6%, and the energy consumption is reduced by 66.1%. During land levelling process, the throttling loss of the electric excavator is reduced by 49.6% and the energy consumption is reduced by 38.1%. The research results will provide new methods for the electrification of construction machinery.