A Three-Phase Electromagnetic Harvester with a Single-Spring Coupled Moving Magnet Assembly

Vibration energy harvesting is a promising approach to support and supplement power, thereby extending the lifetime of low-power sensor nodes under suitable vibration conditions, i.e., in environments where sufficient ambient vibrations are available. It is not a universal autonomous power-supply solution, particularly when generalized across the Internet of Things (IoT), because the harvested power is typically limited to the µW–mW range and depends strongly on the vibration frequency content, amplitude, and operating point relative to resonance. Furthermore, many practical harvesters rely on resonant mechanisms, which are inherently narrowband, and therefore their performance can degrade significantly under detuning or broadband/variable-frequency excitations. In addition, energy-management and power-conditioning electronics (rectification, storage, and regulation) are required to convert the generated electrical energy into a stable and usable DC supply for practical loads. In this work, we develop a nonlinear state-space model of a three-phase electromagnetic vibration energy harvester with spatially displaced coils and evaluate its electrical output characteristics and DC power behavior using numerical simulations.