LAUSR

Energy harvesters generally comprise structures in which a moving magnet is used to generate an induced electromotive force in stationary coils. Vibration is widely used as an external energy source by harvesters, and more efficient energy conversion can be obtained at larger vibrational amplitudes and higher frequencies. In this study, a magnetic-fluid-based electromagnetic energy harvester that can harvest energy with small-amplitude low-frequency vibration is proposed. Cases in which back-iron or air yokes were placed in harvester magnetic circuits were studied. The back-iron yoke reduced the magnetic resistance of the magnetic circuits, thereby increasing the magnetic flux generated in the permanent magnets and ultimately increasing the induced electromotive force. Harvesters with both types of yokes were built and the superiority of back-iron-yoke harvesters was verified through induced electromotive force characteristic tests.