A New Method of Improving Low-Speed Performance of Variable Speed Hydraulic Systems: By Leaking Parallel Valve Control

摘要

Aiming at improving low-speed performance of variable speed hydraulic systems, the leaking parallel valve control is applied to the system during low-speed period. This method increases system damping ratios by increasing leakage controlled by the valve. In addition, the increase of damping ratios just compensates the reduction of damping ratios due to the friction negative slop, which helps to improve low-speed stability and achieve lower critical speed. In the whole process of closed loop control, the system in leaking parallel valve control has good speed performance with more stable and suitable damping ratios and basically avoids pressure impact at start and stop stages and still keeps comparatively high efficiency because the pump provides total flow and the valve only leaks out few flows.