Development of a miniaturized rotational electromagnetic energy harvester with a liquid metal direct-write process

This research proposes a new method for producing micro-coils, which are used in a rotational power generator. A self-developed liquid metal forming system is used to produce a micro-coil that has a low roughness surface, is conductive, and has plane and out-of-plane wiring. For the coil size design, simulation is used to predict the feasibility of using the stray magnetic field to increase induction power generation. The coil is then integrated with a multi-pole NdFeB magnet and applied to an eccentric mass action rotational power generator. Environmental rotational power is converted by rotational machinery and electromagnetic conversion to produce inductive voltage and generate power. The experimental results show that the packaged generator is ∅22 mm × 12 mm thick in size and can output 120 mV at a rotational speed of 3.9 krpm. The output power is 20.3 μW. The power is stored in a super capacitor to realize an independent micro power generation device.