Preliminary Development of an Ultra Low Power Electro-Permanent Magnet Based Actuator for Microfluidic Systems

Abstract

An electro-permanent magnet based actuator has been proposed to control microvalves, which significantly reduces the energy consumption of solenoid type microvalves. Electro-permanent magnets are designed with combined hard and semi-hard magnetic materials to control the direction of the magnetic flux. Power is supplied to these magnets only to change the polarity of a magnet so that it can attract or repel the load. Therefore, power is only consumed to toggle between the states of the valve, while the actuator requires no power to maintain either close or open states at other times. Initial experiments revealed that a voltage as low as TV can be applied across the coil to switch the magnetization direction, which resulted in drawing a current of 1.76A during the current pulse duration of 100μs. The momentary power consumption was 12.37W, but the total energy consumption was only 1.237mJ for a state toggling. For applications where the valves are operated infrequently, this technique is highly energy economical as power is consumed for a very short period of time during actuation. Supercapacitor buffering is suggested to smooth out the energy requirement of the proposed actuator to make wireless low power transfer a possible solution for microfluidic systems with infrequent valve operations.