A Magnetoelectric Composite Energy Harvester and Power Management Circuit

This paper proposes a ferro-nickel (Fe-Ni)/PZT H-type fork magnetoelectric (ME) composite structure and an energy management circuit for ME energy harvesting. The resonant fork composite structure with a high Q value shows a higher ME voltage coefficient and a stronger power coefficient compared with the conventional rectangular composite structure. The resonant fork composite structure can obtain an output power of 61.64 μW at an ac magnetic field of 0.2 Oe. The ME sensitivity of the fork structure reaches 11 V/Oe. For weak magnetic-field environment, an active magnetic generator and a magnetic coil antenna underground are used for producing an ac magnetic field of 0.2-1 Oe at a distance of 25-50 m. A management circuit of the power supply with matching circuit, energy-storage circuit, and instantaneous-discharge circuit is developed suitable for weak electromagnetic energy harvesting. The management circuit can continuously accumulate weak energy from the fork composite structure for a long period and provide a high-power output in a very short cycle. While the voltage across the storage supercapacitor is over 0.36 V, the instantaneous-discharge circuit can drive a wireless sensor network node with an output power of 75 mW at a distance of over 60 m.