High Efficiency Electromagnetic Energy Harvester for Railroad Application
A mechanical motion rectifier (MMR) based energy harvester is designed to harness the vibrational power from railroad track deflections due to passing trains. Whereas typical existing vibration energy harvester technologies are built for low power applications of milliwatts range, the proposed harvester will be designed for higher power applications such as major track-side equipment. This includes warning signals, switches, and health monitoring systems, which typically require a power supply of 10–100 Watts. To achieve this goal we implement the MMR, a newly patented motion conversion mechanism which efficiently transforms irregular pulse-like bidirectional linear vibration into regulated unidirectional rotational motion. The single-shaft MMR design improves previously developed motion conversion technologies, increasing energy harvester efficiency and power harvesting potential. Features of the MMR include bidirectional to unidirectional motion conversion and flywheel speed regulation. Its advantages include improved reliability, efficiency, and steadier output power. Harvester prototype testing results illustrate features and benefits of the MMR based harvester, showing reduction of continual system loading, regulation of generator speed, and capability for continuous DC power generation.