A NEW MULTI-DIMENSIONAL LOW-FREQUENCY SPRINGLESS PROXIMITY INERTIAL HARVESTER FOR CONVERTING HUMAN AND ENVIRONMENTAL MOTION

This paper discusses a new type of energy harvester for converting multi-axial and low-frequency motion from humans and the environment. The harvester uses a spring-less spherical magnetic proof mass to capture kinetic energy from the environment, after which an array of transducer OcellsO employing a novel actuation method are used to convert the mechanical energy into electricity. The contactless actuation mechanism uses attraction between the proof mass and a magnetic fluid to induce a physical parameter change in a variable capacitor thereby allowing the coupled energy to be transduced using electrostatic means. A variable-permittivity prototype is fabricated and tested, illustrating the basic principle and concept. Capacitance variation of 40-80 pF (20% of absolute capacitance) is demonstrated using a 25 mm 2 prototype capacitor cell. The cell is shown to operate for magnet velocities as high as 6 mm/s. With a 100 V pre-bias, 472 nJ/transition can be expected.