Research Of Magnetostrictive Vibration Generating Theory And Energy Harvesting Circuit

Vibration generator of Magnetostrictive materials become a research hotspot in recent years. It can be used in the wireless sensors and other embedded, portable electronic devices which traditional power supply can’t directly provide electric energy. In the background of energy crisis, the research on vibration energy harvesting based on magnetostrictive materials has potential to the problems that need to replace power supply frequently. Countries all over the world get more and more attention of it.Based on the structural dynamic theory of Euler-Bernouli beam, the linear constitutive equations of magetostrictive material and the Faraday law of electromagnetic induction, a distributed parameter mechanical–electro coupled dynamic model of Galfenol cantilever vibration energy harvester has been established, and the frequency characteristic of the device has been derived from the proposed model. The output voltage, current, power and tip relative displacement of the device under acceleration excitation have been calculated. Comparisons between the experimental and calculated results show that the proposed model can provide a reasonable data trends of the device under low acceleration levels and can predict the mechanical–electro bidirectional coupled dynamic characteristics of the device.Then the model’s mechanical parameters is turned into equivalent electrical parameters. Thus, the theoretical model of magnetostrictive generator can be represented in the form of circuit. It gives great convenience for the design of energy harvesting circuits. In the harvesting circuit, We used a voltage quadrupler to improve output voltage, It can provide 4 times the peak input AC voltage at its output.Then a DC- DC transforming circuit is used for the purpose that the load can be achieved a relatively steady DC voltage.This greatly enhance the practicability of acquisition circuit.In this paper, We research the vibration energy harvester of magnetostrictive material in the whole viewpoint, establish a mechanical-electro coupled dynamic model and design energy harvesting circuit, It has great guidance to design the harvester of Magnetostrictive materials.