MEMS AlN Piezoelectric Beams with Integrated NdFeB Magnets for Power Line and Rotational Motion Energy Harvesting

On-chip power autonomy is a central objective of energy harvesting technologies. The integration of piezoelectric and magnetic materials with silicon-processing could address proof-mass size and broadband motion operation limitations. In this work, a MEMS device combining a silicon-based, AlN piezoelectric beam with an integrated NdFeB tip magnet is proposed as an energy harvesting transducer. The device is evaluated for rotational motion and power line energy harvesting use cases. In the rotational motion evaluation, a voltage output peak of 0.35 V is demonstrated from a permanent magnet passing at 4 mm distance. In the power line evaluation, an output power delivery of 5 μW on an ohmic load is demonstrated, at 10 mm distance from a power line carrying an RMS current of 13 A. These results show promising performance towards micro-chip integrated energy autonomy, suitable for time-varying magnetic field and relative structural motion environments.