A New Scheme for Dynamic Response Improvement of Variable Speed Pump Control Systems: Leaking Valve Control

A new control scheme: leaking valve control (LVC) is developed, in order to improve the dynamic performance of variable speed pump control (VSPC) systems. In the control scheme, a control valve operating at leaking status, to regulate the system flow with a variable speed pump. In the paper, the LVC system is designed, and its mathematical models are built, system parameters and control performances are analyzed with subsequent experimental verification. Results show that, after introducing the valve control, the hydraulic natural frequency does not change, but the total leakage coefficient and damping ratio increases significantly and vary widely with operating points; LVC respond faster than VSPC because the control valve could rapid regulate flow, but LVC is applicable to a small range of speed regulation for keeping relatively high system efficiencies. Therefore, the LVC might enrich the control approaches of current hydraulic systems.