On the Design of Energy-Saving Fluid Power Converter

The high energy efficiency and lightweight are recent trends in mobile hydraulics. In this paper, a new energy-saving fluid power converter (FPC) is designed to solve the problem of low energy conversion efficiency in hydraulic systems with variable load. The FPC is a kind of hydraulic transformer, it is similar to the DC transformer in working principle. Pulse width modulation (PWM) signal is used to control the high-speed on-off valves, and the high-speed on-off valve can switch supply ports between different pressure oil sources to achieve the adjustment of the FPC's output. The FPC's mathematical principle is analyzed in this paper, the influence of the friction between the inertial mass and the conversion cylinder on the system efficiency is studied. The influence of the PWM signal frequency, conversion cylinder cross-sectional area and inertial mass on the characteristics of FPC system is deduced. The results of the analysis are validated by Matlab/Simulink, and suggestions of selecting the design parameters of FPC are provided.