Research and development of micro electret power generators

As the size of the electronic system continuously reduces, it is very important to develop micro power generator, which has characteristics of small volume, light weight, high energy density and continuous energy supplying. Vibration energy exists widely in daily environment. Micro vibration power generator can harvest and exchange the vibration energy to the electrical energy. Micro electret power generator is one kind of the power generators for harvesting vibration energy and has been paid much attention by researchers. This paper describes the development and status of micro electret power generators, including electret materials and charging methods, vibration energy harvesting structures and conversion efficiency improvement.