Design Of Novel Capacitive Micro Vibration Energy Harvester

Energy harvesting technology is a high-tech development based on the semiconductor field, this technology can take advantage of the surrounding environment to collect energy such as sunlight, wind, tides, vibration, so as to solve the bottleneck of the wireless sensor networks in the energy self-sufficiency. By the mechanical vibrational energy is converted into electrical energy technology has been widely studied, capacitive vibrational energy harvester and MEMS (micro-electromechanical system Micro-Electro-Mechanical Systems) technology, however, has a better compatibility, and therefore has better development prospects as well. Capacitive vibrational energy harvester through a change in capacitance caused by the change in voltage or electric quantity, through the load, the current is generated, and then the vibration energy is converted into electrical energy. The harvester has the characteristic of simple structure, convenient processing, without harmful gas emissions, which is a new kind of energy conservation and environmental protection devices. However, the problems of how to simplifying the structure of capacitive energy harvester, and making its structure more solid and reliable, still needs the researchers to solve. This paper defined a new type of capacitive micro-vibration energy harvester, and demonstrated the feasibility of the device from two aspects of the theory and processing technology, So as to provide a theoretical basis for further research and experimental experience.Main contributions of this thesis are the following:1. Introduce the several kinds of energy harvester systems, analyze the capacitive vibrational energy conversion mechanisms, create the energy equations, and design the topologies of capacitive vibrational energy harvester.2. Define a theoretical model of capacitive energy harvesting device, analyze the resonant characteristics and equivalent circuit, and make some theoretical calculation of the harvester.3. The polydimethylsiloxane(PDMS) was applied as elastic materials in energy harvester, this material has high flexibility. When the vibration occurs, the upper and lower plates can produce relative displacement in different directions. Compared to previous silicon beams made of springs, polydimethylsiloxane has better elastic structures and can make the micro energy harvester stronger. The electrets are made of silicon materials depositing on the electrode plates, and charge the electrode plates before bonding processes so that the electrets can get a higher electric potential. Under such circumstances:acceleration of1g and vibration frequency of100Hz, it can generate39.4μw of energy by calculations.4. Use ANSYS to analyze the PDMS elastic blocks in the energy harvester structures by finite element method. The simulated results can be calculated in the ANSYS, and then compared to the results which are obtained from theoretical calculations, so as to provide the reference for further analysis.