Efficient energy conversion in low-voltage antiphase rotational energy harvesters using a mechanical motion-based rectifier

• Antiphase motion improves the electrical output performance of the harvester. • A novel mechanical motion-based rectifier is designed for the harvester. • Two diodes are removed in rectification, accompanied by less threshold voltage. • An accurate theoretical model is established for the novel rectifier system. • 20% additional power supply time demonstrates its application potential. Bridge rectifiers play a critical role in converting AC power into DC power in energy harvesting systems, often using an H-bridge topology with four diodes. However, for low-voltage rotational energy harvesters (REHs), the voltage drop caused by traditional rectifiers critically reduces conversion efficiency. To address this, a novel mechanical motion-based rectifier featuring a dynamic contact holder is proposed for antiphase REHs, eliminating voltage thresholds of 0.2 to 0.7 V and significantly enhancing AC/DC conversion efficiency. This design also reduces the number of diodes required, simplifying the circuit and lowering costs. Bench tests show a 29.9 % increase in load voltage, while application tests demonstrate a 19.43 % increase in effective operating time of an electronic device. The rectifier voltage ratios of 0.517 and 0.996 when replacing high-threshold diode rectifiers, underscoring its superior performance under low coil relative speeds and low load impedance. The innovative rectifier ensures stable and efficient energy transfer, even under fault conditions such as misalignment. This technology has potential applications beyond electromagnetic REHs including piezoelectric and triboelectric energy harvesting systems, offering a promising avenue for advancing energy harvesting efficiency.