The Power Generation And The Dynamic Research Of The Bistable Piezoelectric Electromagnetic Combined Vibration Energy Harvester

With the rapid development of the microelectronic technology,and the emergence of new low-power products,the energy supply for low power products has become a hot study topic.The energy storage of the conventional chemical battery is small,and the conventional chemical batter pollutes the environment.So,the new energy harvester needs to be studied.Since the conversion efficiency of the vibration energy is the greatest in the environment,it is very important to convert the vibration energy of the environment into the electric energy.Vibration energy harvesters are the piezoelectric type,the electromagnetic type and the electrostatic type,respectively.Due to the external power supply is required for the electrostatic energy harvesting device,wireless sensors and other low-power field work equipment can not connect to the external power supply,the application of the electrostatic energy harvesting device is limited.The piezoelectric and electromagnetic energy harvesting need not the external power supply,and the vibration energy of the surrounding environment can be converted into the electric energy to supply power for low power products.The conversion efficiency of the piezoelectric and electromagnetic energy harvesting is great,and they can be made into a small structure.It accords with the development trend of the microelectronics technology.Based on the principle of the piezoelectric and electromagnetic power generation,a new bistable piezoelectric electromagnetic combined vibration energy harvester is proposed in this paper.It is also called the bistable multi-mode vibration energy harvester.The subject of the study involves a number of disciplines,including the mechanical,the electronic,the material,the mechanics and other disciplines.In this paper,the bistable piezoelectric electromagnetic combined power generation structure is taken as the study object.Its power generation characteristic and complex dynamic behaviors are theoretically and experimentally analyzed.Firstly,the power generation characteristic of the bistable piezoelectric electromagnetic combined energy harvester is experimentally investigated.The power generation efficiency of the new structure is greater than that of the conventional piezoelectric power generation structure.Subsequently,the bistable multi-mode power generation structure is optimized.The influence of parameters on the power generation and the vibration characteristic of the system is analyzed,and optimal parameters are obtained.Then,the stiffness characteristic and the dynamic behavior of the system are explored.Finally,the nonlinear dynamical equation of the bistable multi-mode power generation structure is established.The numerical simulation of the dynamical equation of the system is carried out by software.Theoretical results are compared with experimental results.This paper consists of following sections.(1)The power generation characteristic of the conventional piezoelectric beam structure and the bistable multi-mode power generation structure are experimentally studied.The influence of the external excitation frequency and the external excitation amplitude on the power generation characteristic of the system is analyzed.(2)The bistable piezoelectric electromagnetic combined vibration energy harvester is optimized.The influence of the spring on the power generation of the system is studied.Subsequently,the influence of the magnetic distance,the spring,the coil and the external load on the power generation of the system is analyzed.The optimal parameters of the system are obtained.(3)The stiffness characteristic and complex nonlinear dynamic behaviors of the bistable piezoelectric electromagnetic combined vibration energy harvester are experimentally studied.The influence of the external excitation frequency,the external excitation amplitude,the magnetic distance and the spring on dynamic behaviors of the system are investigated.(4)The partial differential dynamical equation of the bistable piezoelectric electromagnetic combined vibration energy harvester is established by using the Hamilton principle.Then,the partial differential equation of the potential energy of the system is established.Subsequently,the ordinary differential equation of potential energy of the system is obtained by using the Galerkin method.Relations between the bistable phenomenon and the potential energy function of the system are analyzed.The influence of the magnetic distance on the potential energy of the system is explored by using the maple software.(5)The partial differential dynamical equation of the system are discretized by the Galerkin method.The perturbation analysis of the ordinary differential dynamical equation is carried out by using the multiscale method.The average equation of the polar coordinate is obtained.The average equation is numerically simulated by using maple software.Then,the partial differential electrical response equation of the system is established,and the equation is discretized to obtain the ordinary differential electrical response equation of the system.Subsequently,the dynamical equation and the electrical response equation of the system are numerically simulated by matlab software.The influence of the external excitation amplitude and the external excitation frequency on dynamic behaviors of the system are studied by the waveform,the phase portraits and the poincare map.