The basic phenomena of a cantilever energy harvesting device based on iron-gallium alloy magnetostrictive material for low frequency were systematically studied. The results highlighted how the physical parameters, geometric structure and bias conditions affected the vibration harvesting capacity through a thorough experimental aimed at enhancing the vibration energy harvesting capacity through an optimal design. How the performance is affected by the configuration of the multi-layers composite beam, material and dimensions of the elastic layer, arrangement position and number of bias magnets, the matching load resistance and other important design parameters was studied in depth. For the first time, it was clearly confirmed that the magnetic field of bias magnets and electromagnetic vibration shaker have almost no effect on the measurement of the voltage induced from the harvester. A harvesting power RMS up to 13.3 mW and power density RMS up to 3.7 mW/cm3/g was observed from the optimized prototype. Correspondingly, the DC output power and power density after the two-stage signal processing circuit were up to 5.2 mW and 1.45 mW/cm3/g, respectively. The prototype successfully powered multiple red light emitting diode lamps connected in a sinusoidal shape and multiple red digital display tubes, which verified the vibration harvesting capability or electricity-generating capability of the harvester prototype and the effectiveness of the signal converter.

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At present, the most convenient and effective method for ensuring air pressure inside automobile tires being kept in normal state is using a tire pressure monitoring system to monitor the tire's interior pressure and temperature in real time. Aiming at the power supply problem of direct tire pressure monitoring system in automobile industry commonly, a new giant magnetostrictive vibration-power generation technology which generates electricity through collecting vibration energy in automobile is proposed. Based on the coupling effect of inverse magnetostrictive effect and Faraday electromagnetic effect, a power generation device prototype which uses giant magnetostrictive material as the core element is developed. It may be a prototype of giant magnetostrictive vibration-power generation module used to provide electricity to tire pressure monitoring system instead of button battery power supply mode. In order to accurately describe the relationship between vibration force (stress) and output voltage in the giant magnetostrictive vibration-power generation process, a mathematical model is established from the essence of inverse magnetostrictive effect. According to energy conversion process generated in the process of power generation using giant magnetostrictive material, the modeling process is divided into two parts. Moreover, in order to derive the energy conversion efficiency of giant magnetostrictive vibration-power generation device, a computing method of power generation efficiency is proposed. Experiment results show that the model can accurately describe the relationship between vibration force (stress) and output voltage. Amplitude of the output voltage generated by giant magnetostrictive vibration-power generator is proportional to the amplitude or frequency of vibration force approximately. For the giant magnetostrictive vibration-power generation prototype developed in this paper, its energy conversion efficiency reaches 32.6%. Research result provides an effective method for solving the power supply issue of tire pressure monitoring system. It plays a certain promoting role for the realization of battery-less tire pressure monitoring system.

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