Dynamic performance and temperature rising characteristic of a high-speed on/off valve based on pre-excitation control algorithm

High speed on/off valve (HSV) is an essential component in aerospace digital hydraulic systems (ADHS). Dynamic performance and temperature rising characteristic are two important features, which determine the performance of HSV, and affect the response speed and reliability of ADHS. Increasing the driving voltage is an effective method for improving the dynamic performance of HSV. However, continuous high voltage excitation will lead to more wasted energy, higher temperature rising and lower reliability. To solve this problem, a pre-excitation control algorithm (PECA) is proposed in this paper based on the theoretical model of the influence of electrical parameters on dynamic performance and temperature rising characteristics. In PECA, an appropriate initial coil current is generated by pre-excitation instead of increasing driving voltage, which significantly shortens the switching delay time. Then, based on real-time current online calculation and feedback mechanism, the adaptive switching of five equivalent voltages is realized. Consequently, the coil current can be rapidly kept at the expected state without consuming more energy and generating more heat. Results indicate that compared with conventional PWM control algorithm, the PECA can improve dynamic performance of HSV, shorten the total switching time by 71.5%, and increase the maximum operation frequency. Therefore, the linear area of flow characteristic is expended by 80.0%, the adjusting time of HSV-controlled system is reduced by 23%, while shortening steady error by 46.7%. Moreover, the temperature rising characteristics of HSV are better, the maximum operation temperature is reduced by 68.6%, and the time to reach the steady state temperature is shortened by 20%. From the results, it can be concluded that the PECA is not only an effective and practical control algorithm for improving the performance of HSVs and HSV-controlled systems while reducing the heat generation and decreasing the temperature rising of HSV, but also can be a potential solution in ADHS.