Digitally-controlled driving power supply for dual-active-valve piezoelectric pump

Abstract

The dual-active-valve piezoelectric pump (DAVPP) can achieve a precise and bidirectional delivery of liquid with flexibility through multiple control methods. Compared with the unidirectional piezoelectric pump, DAVPP has broader application prospects. For instance, for medical applications, DAVPP is promising to complete blood sample collection as well as drug injection in minute and accurate quantities, further to realize the integration between automatic diagnosis and disease treatment. The objective of this work is to keep DAVPP in operation with an innovative newly developed digitally-controlled driving power supply. First, a direct digital synthesis technology was adopted to generate two sine signals with an adjustable frequency and a phase difference. Then, a T-type resistor network was applied to regulate the voltage. Finally, high-voltage and power amplifying unit was utilized to achieve a sufficient driving ability. A prototype of the supply was made and its driving characteristics were tested in experiments. Experimental results demonstrate that the sine waveform output is satisfactory, the maximum voltage is up to 175 V, the frequency range is 5–500 Hz with a minimum resolution of 1 Hz, and the phase difference can be regulated from 0° to 360° with a minimum resolution of 11.25°, which perfectly matches the driving requirements of DAVPP. Control variables of DAVPP (namely driving voltage, frequency and phase difference) can be adjusted independently and continuously. By adjusting the driving phase difference, the direction of a liquid delivery can be changed, meanwhile, the output flow rate and output pressure can also be modulated smoothly.