A Phase Modulation Method of Sine Signal for Dual-active-valve Piezoelectric Pump

Abstract A phase modulation method with wide range and high resolution for sine signal is essential for a dual-active-valve piezoelectric pump (DAVPP) control. In DAVPP, by phase modulation, the flow direction can be changed, the output flow rate and pressure can be precisely adjusted. In this article, the authors developed a phase modulation method for sine signal. This method is characterized by both the combination of hardware and software, and the combination of digital circuit and analog circuit. In hardware, a sinxcosφ constructing circuit and a cosxsinφ constructing circuit are specially structured, which enables phase modulation to be achieved. In software, the output phase is determined by the digital controlling quantities sent by the main control chip and stored in the form of a table. Analytical formulas of the cosine constructing table tab_cos and the sine constructing table tab_sin are analyzed and structured. Experimental results show that the output phase can be regulated linearly and continuously, within a range of 0° to 360°. Its resolution can be improved according to the requirements. Although the modulation process and circuit are simple, it can effectively solve the problem of sine signal phase modulation for DAVPP control.