A non-intrusive magnetic energy scavanger for renewable power generation state monitoring

To increase the reliability of renewable energy production, the local environment variables have to be monitored closely, such as the chamber/nacelle temperature and humidity. In such harsh working conditions, acquiring auxiliary power for such sensor load can harm system reliability if the power is drawn directly from the supply or load lines. This paper proposes a non-intrusive power supply system for the sensor load by harvesting the near field magnetic power from the current enriched supply cables. The size and turn number of the magnetic field harvester coil is calculated and verified by the finite element model. A two stage power conditioning circuit is designed, consisting of a 4X voltage multiplier followed by an energy feed-forward enabled buck converter. The prototype of the energy scavenger is implemented and tested on a current ripple enriched cable; the experimental results indicate that the scavenger can harvest more than 30mW from the power cable with 10kHz 7A RMS ripple component.