Wireless Power Enabled Ultra-Energy Efficient Bi-Stable Actuator for Microfluidics

Abstract

In the past few decades microfluidic systems have gained significant interest both in academia and industry. They are used for chemical analysis where small quantities of fluids are treated using special components such as microvalves, micropumps and micromixers. The automated biochemical laboratory is a microfluidic platform that studies the toxic effects of chemicals on Zebra fish embryos. This platform operates several solenoid microvalves for very long hours leading to a large power consumption. To improve the portability of the system the power consumption needs to minimised to reduce the required battery capacity. This thesis aims to develop a new energy efficient microactuator to reduce the power consumption of these solenoid microvalves. The thesis proposes a novel microfluidic actuator for microvalves, with bi-stable actuation, wireless power and wireless actuation control, which is significantly more efficient than state of the art microvalves reported in literature. An ultra-energy efficient bi-stable actuation mechanism, primary and secondary wireless power supply circuits and wireless actuation control has been designed and implemented. The actuation mechanism, magnetic and electrical circuits of the actuator and power supply have been theoretically modelled and analysed. Here the actuator is driven by electropermanent magnets, together with an inductively coupled wireless power transfer system and supercapacitor based energy buffering. Energy gradually extracted through the wireless power transfer system, accumulated on the supercapacitor buffer, provides momentary peak power for actuation only. The microactuator also features a unique communication mechanism to deliver the valve control signal to the microactuator. It has been shown experimentally that the new microactuator reduces the energy consumption of the automated biochemical laboratory by an order of two. This microactuator also features ultra-fast, bi-stable actuation, significant deflection and force capabilities. This novel microactuator provides wireless power and control, ultra-energy efficient actuation, high deflection and force capability, making them a unique class of microfluidic actuators.