Saving energy control of cylinder drive using hydraulic transformer combined with an assisted hydraulic circuit

A newly assisted hydraulic circuit is proposed for a hydraulic transformer to improve energy saving potential of the system. The use of three directional controlled valves with the designed controller forces the transformer and the cylinder work in proper conditions, which contributes to improve energy utilization of the system. A model of hydraulic transformer including energy losses of the pump/motor is used to estimate energy consumption in different situations. A switching method based on desired load is also designed to select a feasible operating mode of the system. Simulation results indicate that saving energy is significantly improved by the proposed circuit.