Abstract:In view of the low energy efficiency, large battery installed capacity and short battery life caused by existing electric excavators in using multi-way valve control system,a variable speed dual pump direct drive hydraulic excavator boom system was proposed.According to the area ratio of the boom hydraulic cylinders,the displacements of two hydraulic pump/motors were configured to achieve the flow matching of the hydraulic cylinder.The hydraulic accumulator and super-capacitor were used for hybrid energy storage to realize the efficient recovery and utilization of the gravitational potential energy of the boom.The working principle of the proposed system was analyzed,the multi-subject coupling simulation model of the system was established,and the system operation characteristics and energy characteristics were analyzed.The research results show that the dual pump direct drive excavator boom system has good control characteristics and stable speed operation.Compared with the traditional multi-way valve control system,the boom system of the dual pump direct drive system has a remarkable energy-saving effect.When the accumulator pressure is 21 MPa and the volume is 180 L,the gravitational potential energy recovery efficiency is 79.9%,and the energy consumption is reduced by 64.6%.Further,the energy-saving effect of the dual pump direct drive boom system can reach more than 65% through reasonable selection of the accumulator working pressure and volume.