An Improved PWM Control for Landing Velocity Reduction and Dynamic Performance Preservation in High Speed Solenoid Valve During Excitation Stage

High speed solenoid valves (HSVs) have often been used in the pilot stage of a two-stage proportional valve to control the main spool's position, in which the vibration and dynamic performance of the pilot HSV need to be optimized, such as low vibration, low noise, and fast response. In this paper, an improved PWM controller for landing velocity reduction in a HSV during the excitation stage is proposed to reduce the vibration and maintain the dynamic performance under different supply pressures. First, the working principle of the proposed PWM signal is presented and the dynamic behavior of the HSV is analyzed during the excitation stage. Secondly, the influences of the two timing parameters (the time when the negative voltage begins and ends) and the hydraulic supply pressures on the performance of the HSV are analyzed. Moreover, two design criteria of the timing parameters are proposed and a direct searching algorithm is proposed to find an optimal solution set. The optimization results not only show that a good compromise between the landing velocity and the total opening time can be achieved but also proves that the reverse motion of the ball valve is effectively eliminated. Finally, comparative results indicate that with the proposed PWM control, the maximum impact acceleration is reduced by at least 44.7% and the delay of total opening time is always less than 0.3 ms under different supply pressures except 1 MPa, compared to the compound PWM control (full positive voltage in the excitation stage). The proposed PWM is simple and can be used in the HSV-controlled system to reduce the vibration and improve the accuracy of the actuator.