Switchable Frequency Response Based on Electropermanent Magnet Actuator for Wide-range Operation of Electromagnetic Devices

This paper proposes a linear oscillatory actuator (LOA) that can switch its degree of freedom (DOF) for the purpose of improving its frequency response. Electropermanent magnet (EPM) is utilized as an energy-saving solution to switch DOF by absorbing and desorbing secondary mass with primary mass. EPM is a magnetic circuit which uses two different magnets: NdFeB magnet (high coercivity) and AlNiCo magnet (low coercivity). We derive two motion equations under absorption and desorption of the masses. The operational principle of the EPM is described. We evaluate absorption and desorption of the masses through numerical calculation through MATLAB/Simulink and JMAG-Designer. The primary mass successfully absorbed the secondary one due to the electromagnetic attractive force of the EPM generated by a short-time pulsed current. The desorption motion was also successful because the short-time pulsed current demagnetized the AlNiCo magnet and eliminated the attractive force of the EPM.