A radial array-based compact electromagnetic vibration energy harvester for low-amplitude vibration environments

Abstract The advancement of internet of things technology relies on wireless sensor networks, where sustainable power for sensor nodes can be provided by mechanical vibration energy. Maximizing the harvested power within limited spaces is a critical research focus. Unlike conventional electromagnetic vibration energy harvesters that predominantly employ single permanent magnets, this work adopts a radial array magnetic configuration to enhance output power in low-amplitude vibration environments. A theoretical platform is established for designing and analyzing such harvesters. Specifically, pole shoes are modeled as circumferentially magnetized permanent magnets. Their equivalent residual magnetic flux density is calculated using an equivalent magnetic circuit model, and this value is fed into a subdomain model to derive closed-form solutions for the magnetic field. Parameter analysis validates the model’s accuracy within applicable ranges and elucidates how design parameters affect dynamic power output. A prototype harvester was fabricated and evaluated using a vibration exciter. Experimental results show good agreement with theoretical predictions. This work aids engineers in understanding radial array harvesters and optimizing their design, while also providing insights for other energy systems employing radial arrays.