Structural Analysis Of Hybrid Energy Harvester And Design Of Energy Management Circuit

With the rapid development of microelectronics manufacturing technology, wireless sensor networks and the emergence of various new low-power devices, vibration energy harvester which convert vibrational energy from the environment into electrical energy directly have became a research focus in recent years. Based on piezoelectric energy harvester and electromagnetic energy harvester, researchers have proposed a hybrid piezoelectric-electromagnetic energy harvester. In this paper, the structure and the energy management circuit of double-clamped beam- mass hybrid piezoelectric- electromagnetic energy harvester have been studied, and its performances are studied by therotical analysis,simulation and experimental test.1 For the structure of the hybrid piezoelectric-electromagnetic energy harvester, the working mechanism of three subsystems(mechanical vibration unit, electromagnetic energy harvester unit and piezoelectric energy harvester unit) has been analyzed, and the output characteristic of the hybrid piezoelectric- electromagnetic energy harvester has been simulated by ANSYS and ANSOFT MAXWELL.2 The energy management circuit is the key to design a self-powered system. In practical applications, energy harvesting circuit converts AC current to DC current, then the super capacitor and rechargeable battery or any other energy storage devices are charged by the energy storage circuit, the energy is released when microelectronic devices need. In this paper, LTC3588-1 and LTC3108 energy conversion chips are choosed to design energy harvesting circuit which can harvest both piezoelectric energy and electromagnetic energy and output stable DC voltage. And in terms of the energy storage circuit, charge and discharge characteristics of super capacitor and rechargeable battery are introduced. Super capacitor and rechargeable battery could be charged through the energy management circuit.3 The prototype of the hybrid piezoelectric-electromagnetic energy harvester has been produced and tested through experimental system. On this basis, piezoelectric energy harvesting circuit is accessed to the piezoelectric energy harvester, and electromagneticenergy harvesting circuit is accessed to the electromagnetic energy harvester, wo could get stable DC voltage output. Then piezoelectric- electromagnetic energy harvesting circuit is accessed to the piezoelectric- electromagnetic energy harvester, both piezoelectric energy and electromagnetic energy could be harvested. At last, experiments are made to charge Super capacitor and rechargeable battery.4 In the paper, the developed energy harvesting circuits for piezoelectric energy harvester are summarized,including standard energy harvesting circuit, voltage doubler rectifier circuit, synchronous electric charge extraction circuit and synchronized switch harvesting on inductor. The output efficiency of energy harvesting, characteristics and conditions of the various power management circuitry are compared. Then parallel SSHI board is designed and fabricated to to verify the feasibility of SSHI circuit.