Combinatory piezoelectric and inductive vibration energy harvesters

This paper provides an overview of vibration energy harvesting techniques using combinatory piezoelectric and inductive vibration energy harvesters. We provide detailed analysis of both mechanisms by comparing and contrasting the design, operating principle, and performance of each harvester. After introducing the two types of mechanisms, we discuss the methods to increase the power density through optimization of electromechanical coupling factor. The electromechanical coupling factor directly couples the input mechanical energy to the output electrical energy. The paper concludes with review of state-of-the-art for combinatory vibration energy harvesters citing their volume and bandwidth.