Design And Performance Optimization Of Micro-power Based On MEMS Vibration Energy Harvester

The Internet of Things(IoT)Technology has been rapidly developed as the increasingly mature of sensor technology and networking technology.There are tens of thousands of unpowered devices included in the sensing layer of IoT.The power consumption of the unpowered devices can be reduced to microwatts by the existing technologies,but some power supply demands such as sustainability,stability,integration and environment protection cannot yet be satisfied with the traditional battery.A novel micro power source,which is composed of vibration energy converter module,power collection and storage module,and booster module,is designed in this paper.Integrate the novel power into the unpowered devices to obtain self-powered devices,then provides a better energy supply solution for IoT system.A preferred solution for power supply in IoT system is then provided by the self-power devices which integrate the micro power source into the unpowered devices.On the basis of previous research,this paper firstly focuses on the micro structure,and discusses the influence of the scale effect on the micro-mechanical behavior.And then three modules of micro-power are designed,as well as the performances of each module are studied.Secondly,vibration energy converter module,power collection and storage module as well as booster module,are designed and analyzed.Finally,an advanced energy harvester structure is proposed for the problem existed in the current energy harvester.The main contents and conclusions are listed below:(1)Improvement of micro beam structure dynamic model.For the piezoelectric vibration energy harvester of micro beam structure,the micro beam dynamics model is improved with coupling stress theory and taking the scale effect into account.And the accuracy is verified by experiments.(2)Design of micro-power based on MEMS piezoelectric vibration energy harvester.First of all,numerical simulations are carried out based on the micro cantilever beam type piezoelectric vibration energy harvester model.The affecting factors of power output performance is discussed combined with the test data.Then the circuits of power collection and storage module,as well as booster module are designed by the application of BQ25504 and TPS61020.Finally,the performances of the two modules are researched by TINA.(3)Performance optimization of micro-power.A novel structure composed of multi beams and masses is proposed to solve the problems of high resonance frequency and narrow band,which exist in the energy harvester of the micro power source.What's more,equations to calculate the displacement response and output voltage under external stimulation are deduced.Lastly,the relationships between the response performances(i.e.quantity of electricity and voltage)and the frequency is analyzed for harvester n=2 and n=4.The results have shown that resonant frequency is obviously reduced,and the effective frequency bandwidth is highly broadened.