Theoretical and Experimental Studies of a Digital Flow Booster Operating at High Pressures and Flow Rates

Abstract

The switched inertance hydraulic converter (SIHC) is a new technology providing an alternative to conventional proportional or servo-valve-controlled systems in the area of fluid power. SIHCs can adjust or control flow and pressure by means of using digital control signals that do not rely on throttling the flow and dissipation of power, and provide hydraulic systems with high-energy efficiency, flexible control, and insensitivity to contamination. In this article, the analytical models of an SIHC in a three-port flow-booster configuration were used and validated at high operating pressure, with the low- and high-pressure supplies of 30 and 90 bar and a high delivery flow rate of 21 L/min. The system dynamics, flow responses, and power consumption were investigated and theoretically and experimentally validated. Results were compared to previous results achieved using low operating pressures, where low- and high-pressure supplies were 20 and 30 bar, and the delivery flow rate was 7 L/min. We concluded that the analytical models could effectively predict SIHC performance, and higher operating pressures and flow rates could result in system uncertainties that need to be understood well. As high operating pressure or flow rate is a common requirement in hydraulic systems, this constitutes an important contribution to the development of newly switched inertance hydraulic converters and the improvement of fluid-power energy efficiency.

Special Issue: Smart Flow Control in Micro Scale

“…Yuan et al [26] investigated the dynamics, flow responses and power consumption theoretically and experimentally in hydraulic systems using the switched inertance hydraulic converter (SIHC). Results highlight the superiority of the SIHC in operation involving high pressures and delivery-flow rates.…”

Characteristic investigation of a flow-dependent inertia hydraulic converter driven by an equivalent fast switching valve

“…[15][16][17] In a hydraulic converter using flow-dependent fluid inertance, 18 when the fast switching valve switches from a high-pressure line to a tank line, the fluid kinetic energy stored in the inertance pipe should have continuously drawn the flowing fluid from the tank line to the load due to the existence of fluid inertance. 19 However, as an inherent behavior of SIHCs, 20 the performance of the fluid inertance is heavily affected by nonlinear characteristics including parasitic inductive effect 21 and wave propagation effect 22 within the inertance pipe at each switching period. Even though the SIHCs employing the rigid straight pipes appear simple and economical, an inertance pipe with sufficient length and available diameter is necessary to reach the required inductance.…”

The Hydraulically Controlled Oscillating Piston Converter

“…Ref. [4] gives an overview of this work; [5][6][7][8][9][10][11] are important contributions of recent years. In these cases, the inertia is realized by the fluid in a so-called inertance pipe.…”