Rapid flow measurement for high speed on/off valve based on coil current derivative

The average flow rate of a high speed on/off valve (HSV) is usually obtained by a flow sensor, which leads to pressure loss, structural complexity, and long test time. This paper proposes a rapid flow measurement for HSV based on the coil current derivative. The average flow rate is calculated by the effective opening time, which is solved by the critical moving time according to the proposed flow models. To estimate the critical moving time in real-time, an analytical model between the coil current derivative and the valve’s displacement is derived. Experiments indicate that the error between the linear and nonlinear flow model is small when the frequency is smaller than 50 Hz. Moreover, compared to the linear flow model, the average error of the nonlinear flow model decreases from 0.21 L/min to 0.12 L/min under 100 Hz. The proposed flow measurement method has advantages of rapid measurement, structural simplicity, non-contact, and easy to implement intelligence.