###### Abstract
However, due to the bottleneck of engine development, it is difficult to further improve the energy efficiency. The hybrid power system mainly uses the auxiliary power source to drive the load together with the engine and stabilize the engine working point, to improve the energy efficiency of the engine. However, the configuration and control of the hybrid power system are complicated. Moreover, the engine is employed in hybrid power technologies. The improvement in energy efficiency and emission are still unsatisfactory [12; 13]. Electric construction machinery uses a motor to replace the engine, in which high energy efficiency and zero emission can be achieved. It is considered to be one of the important trends in the development of construction machinery [14; 15; 16]. At present, some research has been carried out on electric construction machinery. Some machine manufacturers, including Komatsu, Doosan, Sunward, XCMG, SANY, Liebherr, and Caterpillar, have launched electric construction machinery. However, the electrification technology for construction machinery is still in its infancy. Most electric construction machineries use motors to replace engines and simulate the working mode of engines. The working characteristics of the hydraulic system are not fully considered, which leads to the limited comprehensive matching characteristics of the motor and hydraulic system. At present, many scholars have carried out research on the electrification of construction machinery. [PERSON] et al. used a variable speed motor to drive the pump in a hydraulic system for flow matching. The energy consumption of the power system was reduced from 2.05 to 0.7 kW. The energy-saving efficiency was up to 33%. Compared with traditional excavators, the energy consumption of the whole machine could be saved by more than 30% [17; 18]. [PERSON] et al. used a motor to replace the engine and proposed a two-stage idle speed control system for an electric excavator with an accumulator [19]. The results showed that the fast response during mode switching could be realized. Moreover, the energy-saving efficiency of the system was about 36.06% [20]. [PERSON] et al. carried out research on the electric excavator based on the electro-hydraulic actuator. The integrations of driving and regeneration for the potential energy and the kinetic energy of the excavator boom and swing were achieved, respectively. A 5 t excavator test prototype was developed [21]. Similar research was carried out by [PERSON] et al. as well. Three independent motor pumps were used for the boom, arm, and bucket of a 1 t excavator. The results showed that in the selected typical working condition, the efficiency of the system was 71.3% [22]. At present, electrification technologies have been widely used in the field of automobile, but their applications to construction machinery are still in their infancy. Because of significant differences between construction machinery and automobile in structure, working condition, load and working environment, the research on electrification technology of construction machinery needs to be reconsidered. Based on the LUDV system, to give full play to the excellent speed regulation characteristics of the motor, the research on the flow matching technology through variable speed motor-variable displacement pump for excavator is studied. Meanwhile, the flow prediction for multi-actuators pilot signals is realized, so as to further improve the system efficiency and the controllability.