| Wireless sensor network with its high concealment, low power, small volume, is widely used in every field of life. The traditional wireless sensor network uses batteries mostly, but the battery energy carried is too limited to meet the needs of the work for a long time. Due to vibration is ubiquitous in the environment, transforming the energy produced in the process of vibration into electrical energy, and realizing the sensor self-powered, At the same time, it can meet the needs of the work for a long time.The vibration frequency in the environment distributes in a wide frequency band.The vibration energy harvesters which have the characteristic of broadband vibration energy harvesting can fully harvest vibration energy in the environment. Most energy harvesters use nonlinear method to achieve broadband vibration energy harvesting, and the nonlinear method above is mainly based on the cantilever beam structure. Although this kind of harvester has broadband characteristic, but large amplitude vibration will cause cantilever easily fracture. Moreover, harvesters is directly proportional to the output power and frequency, the higher the frequency is, the greater the power output will be. Combining of frequency characteristic and broadband characteristic can make the power output of broadband vibration energy harvesters higher. However, at present,studies on nonlinear vibration energy harvesters combined with broadband and higher frequency are very little. In this paper, based on the composite magnetoelectric transducer, we put forward a new type of nonlinear broadband vibration energy harvester based on rotary structure, which can not only overcome the shortcoming of cantilever beam is easily broken under the large amplitude vibration, but also have characteristics of broadband, doubling frequency and can output high power. Therefore,the main work of this dissertation is summarized as follows:(1) The research status of nonlinear broadband vibration energy harvesters at home and abroad are introduced, and the disadvantages are summarized. Combined with the output characteristic and working mode of magnetostrictive / piezoelectric laminated transducer, we discussed the main influence factor of the output power.(2) The abstract vibration model of rotary energy harvester is established, and thenonlinear vibration performances of the harvester were studied by using the Lindstedt-Poincare method. The mechano-magneto-electric performances of the harvester were analyzed by combining the vibration equation of the harvester with the magnetoelectric characteristics of the transducer.The model could be used as an analyzing and designing basis for rotary vibration energy harvester.(3) Based on the ME transducer, a rotary nonlinear vibration energy harvester under low frequency vibration was presented to convert ambient vibration into electrical energy. And the regularity of magnetic force and magnetic distance changed with swing angle in the air gap was analyzed by using Maxwell software simulation analysis. We also studied and discussed the two harvesters that using the PZT-5H and PMNT-PT magnetoelectric transducer. The experimental results showed that:1)When the PZT-5H magnetoelectric transducer harvester is used, the acceleration of 0.3 g(1g = 9.8 m/s2) is unchanged, and the output peak-peak voltage goes up to 92.0V. The frequency bandwidth is about 2.7 Hz when voltage is more than 20 V, and the output power goes up to 117 μW;2)When the PMNT-PT magnetoelectric transducer harvester was applied, the acceleration of 0.3 g(1g = 9.8 m/s2) is unchanged, and the output peak-peak voltage goes up to 188.0 V. The frequency bandwidth is about 6.0 Hz when voltage is more than20 V, and the output power goes up to 689.7 μW;the acceleration of 0.5 g(1g = 9.8 m/s2)is unchanged, and the output peak-peak voltage goes up to 246.0 V. The frequency bandwidth is about 9.4 Hz when voltage is more than 20 V, and the output power goes up to 970.23 μW;... |
