Design And Research Of Low-frequency Rotary Energy Harvester Based On Cantilever Beam

Most low-power consumption electronic devices are powered by chemical batteries,and traditional chemical batteries have problems of high pollution,frequent replacement and limited life span.Abundant and renewable vibration energy in the environment is considered as an ideal energy source for low-power consumption electronic devices.By vibration energy harvesting technology,the vibration energy in the environment can be converted into electrical energy to power sensor nodes,and realize the self-powered wireless sensor network.Most of the vibration energy in the environment exists in the form of low-frequency vibrations,but the traditional energy harvester has the problem of high working frequency and low output power,which cannot effectively harvest the low-frequency vibration energy in the environment.Therefore,designing an energy harvester that can efficiently harvest low-frequency vibration energy in the environment has become the focus of researchers.1.To solve the problems existing in traditional energy harvesters in harvesting low-frequency vibration energy,a new type of cantilever-plucked rotor structure is proposed in this thesis.With this structure,low-frequency vibrations in the environment can be converted into high-speed rotational motion of the rotor.Through a new type of plectrum design,the structure can effectively reduce energy loss and improve the efficiency of converting vibrations in the environment into rotation.The plectrum has a simple structure,is mounted on a cantilever beam,and is composed of a rigid part for plucking the rotor and a flexible part for reducing the frictional resistance acting on the rotor.The plectrum is able to automatically switch the effective stiffness according to the motions relative to the rotor rotation.2.On the basis of the rotor structure,an electromagnetic energy harvester is designed.In this thesis,the electromechanical coupling model of the electromagnetic energy harvester based on the cantilever-plucked rotor is established,and the two working modes are analyzed and processed;secondly,the vibration experimental platform is built and the theoretical model is verified to be correct.On the basis of the model,this thesis studies the influence of the load resistance under different accelerations and different structural parameters on the output of the energy harvester.3.After determining the optimal structural parameters of the energy harvester,this thesis makes an experimental prototype and conducts experiments to show the output performance of the harvester.The experimental results show that the low-frequency rotational energy harvester based on the cantilever-plucked rotor can achieve an output power of 4 m W under the sinusoidal excitation with an acceleration of 0.4 g(g=9.8 m/s~2)and the frequency of 8.6Hz,while the traditional cantilever-based energy harvester can achieve an output power of1 m W which is only a quarter of the proposed harvester in this thesis.The output voltage and output power of the energy harvester can meet the needs of powering low-power consumption electronic devices.The low-frequency rotational energy harvester driven by the cantilever beam is proposed in this thesis provides an efficient method to convert vibrational motion into high-speed unidirectional rotational motion,which can effectively harvest low-frequency vibration energy in the environment.Under the condition of low vibration excitation(≤0.8 g),the energy harvester proposed in this thesis can power different low-power consumption electronic devices,verifying its potential as a practical energy source.In addition,in order to demonstrate its output performance under complex conditions,the energy harvester is also used to harvest the energy of human motion to power electronic devices.The experimental results not only verify the output performance of the cantilever-plucked rotor structure is much higher than that of the traditional cantilever beam structure when harvesting low-frequency vibration energy,but also demonstrate the potential of the low-frequency rotational energy harvester based on the cantilever cantilever-plucked rotor to become a substitute for chemical batteries.