Energy analysis of a novel electric-hydraulic hybrid driven press system with multi-modal energy saving management

Hydraulic presses are strategic support equipment in the high-end manufacturing field, but their energy efficiency is low, resulting in unnecessary energy waste. Electric presses have high energy efficiency, but their manufacturing capacity is weak. None of them can simultaneously meet the manufacturing requirements of low energy consumption, high precision, and large forming capacity. To fill this gap, in this paper, the two techniques were combined, and a novel and original electric-hydraulic hybrid driven press system (EHP) was proposed to explore a new energy-saving manufacture method. During the operation, electromechanical transmission is adopted to control the precise movement of the slider, and hydraulic transmission is applied to balance the deformation resistance of the workpiece. In order to reduce energy consumption, a multi-modal energy-saving management strategy was developed. Empty-load falling and returning stages adopt electric drive mode, while the heavy-load forming stage adopts electric-hydraulic hybrid drive mode. Herein, the energy conversion and dissipation characteristics of the EHP were analyzed. Finally, the proposed energy-saving system is equipped on a 50-ton hydraulic press for case study. Compared with the high-efficiency pump-controlled technology, the total energy consumption of the new EHP can be reduced by 30 %, indicating a 43 % increase in energy utilization efficiency. In addition, the positioning accuracy was improved by 78 % with the response time reduced by 66 %. This new EHP fills the gap where existing technology cannot simultaneously meet high energy efficiency and high precision, and is of great significance for energy conservation and low-carbon manufacturing of the large-size presses.