Energy-efficient self-locking micropump system using single bi-stable electromagnetic actuator

While electromagnetic micropumps have potential for the low operating voltage within a compact configuration, the significant power consumption level due to the continuous current input during pumping operations could hinder the application to battery-driven systems such as wearable drug delivery devices. This paper presents an energy-efficient and self-locking micropump system using a single bi-stable electromagnetic actuator with a double-sided tubing. The proposed bi-stable electromagnetic actuator consists of a single-body iron mover and a PM-attached stator, the combination of which can minimize the reluctance of the magnetic flux path induced by a current excitation, thereby achieving the high energy-efficiency. The actuator is integrated into the micropump system with a double-sided tubing configuration, which provides (i) the assistant force during switching motions in order to reduce the energy consumption, (ii) the self-primed pumping operation with a sequence of the pumping phase and the loading phase, and (iii) the self-locking characteristic to prevent unwanted flows during non-operating states. The low-voltage and low-energy characteristics of the proposed micropump system are experimentally validated. The switching voltage and the switching energy are measured to be a minimum of 0.43 V and 1.88 mJ, respectively. The pumping volume is measured to be 1.52 μL per pumping cycle, and the micropump can maintain the self-locking characteristic up to a pressure of 24 kPa by the latching force of 3.7 N from the actuator. The proposed energy-efficient and self-locking micropump system can be readily applicable in various applications where the reliable pumping with the low-power and low-voltage characteristics are required such as wearable drug delivery systems.