A planar electromagnetic energy harvesting transducer using a multi-pole magnetic plate

• We present a novel, low cost, electromagnetic planar energy harvesting transducer.
• Generator uses a multi-polar magnetic sheet and standard printed circuit board.
• Generates energy from vibration, inertial motion, or direct force inputs.
• We develop analytical models to predict output and guide design process.
• Prototypes demonstrate 1.1 mJ of energy production at 9% efficiency.

We report on the development of a new planar electromagnetic energy harvesting transducer. The transducer can be realized with low cost printed circuit board technology and leverages recent advancements in the manufacture of multi-pole magnetic sheets. We develop a detailed analytical model to predict the performance of the transducer and to guide the design process. Several specific features of the model, such as voltage dependence on coil routing, are validated experimentally. The basic transducer can be used for energy harvesting devices using a linear vibration or direct force input. We demonstrate the technology with prototypes that use a direct force input that displaces the proof mass and then releases it, allowing it to freely oscillate. The device performance closely matches simulation and results in 1.1 mJ of generated energy and an efficiency of 9%. The model indicates that fairly simple improvements can push the efficiency up to 20%.