Study Effect of Position of Fixed Magnet on Performance of VEH Device Working on Electromagnetic Principal

Abstract

Vibration energy harvesting (VEH) is one of key source of power for remote locations. VEH device gives maximum output at its natural frequency matching with excitation frequency. So, it is suitable for standalone frequency, gives rise to increase band widening efforts. To achieve resonance, stiffness or moving mass is to be changed. Changing of mass during operation is difficult to achieve. Repulsive and attractive force between magnets can be varied by changing distance between magnets. This paper studies effect of changing fixed magnet position in attractive and repulsive mode on natural frequency of device. One moving magnet oscillates between fixed magnets located at both ends. In repulsive mode, as fixed magnets brought closure, stiffness of spring increases and resonance frequency increases. When distance between fixed magnets is reduced by 16 mm resulted in increasing resonance frequency from 16 to 28 Hz. In attractive mode distance between magnets reduced by 8 mm resulted in decrease in resonating frequency from 14.5 to 10 Hz. But further bringing fixed magnet close result in sticking moving magnet to fixed magnet and energy generation stops.