Combined speed control and centralized power supply for hybrid energy-efficient mobile hydraulics

Improving energy efficiency in mobile hydraulics is paramount and feasible via machine electrification, but all actuators' power in standard systems must flow through the electric motors, which is unfeasible for medium-to-high power applications. Therefore, this paper leverages the idea of splitting the transferred power between the hydraulic and electric domains to save energy while downsizing the electric motors. A novel layout of a hybrid excavator is presented, validated using high-fidelity simulations, and compared to the state-of-the-art, load-sensing machine. The results show the expected system's functioning and efficiency benefits (fuel savings close to 28% compared to the original excavator). Almost 60% of the energy is transferred to the actuators hydraulically minimizing the power rating of the electric machines in favor of the system's cost and compactness. Future research will focus on controlling the hybrid system to maximize energy savings and make it easily applicable to different fluid power machines.