A Portable Micropump System Based on Piezoelectric Actuation
Despite significant efforts to develop micropumps, cumbersome driving equipment means that the design of portable micropumps remains a challenge. This study presents a stand-alone micropump system, which includes a peristaltic micropump based on piezoelectric actuation and a driving circuit. This battery-based driving circuit comprises a 12 V battery, an ATmega 8535 microprocessor, a 12 V-to-180 V DC to DC converter using transformerless technology, three differential amplifiers, an IC 7805, a phase controller, an A/D converter, a keyboard and an LCD module. The system can produce step-function signals with voltages of up to 228 V and frequencies ranging from 10 Hz to 100 kHz, as the inputs for the pump. It is portable and programmable with the package size of 22 cm times 12.8 cm times 9 cm. Additionally, this proposed system is used to design the driving signals of the pump which are 3-, 4, and 6- phase actuation sequences. This work performs the circuit testing and fluid pumping, and demonstrates the effects of actuation sequences on pump performance in terms of the dynamic behavior of the diaphragm, flow rates and back pressure of the system. The experimental results show that the pump excited by the 6-phase sequence results in better performance compared with the 3- and 4-phase sequences, and produces a maximum flow rate of 36.8 mul/min and a maximum back pressure of 520 Pa with deionized water at 100 Vpp and 700 Hz.