A microelectroplated magnetic vibration energy scavenger for wireless sensor microsystems

This paper presents a microelectroplated magnetic vibration energy scavenger based on microelectromechanical systems (MEMS) technology. It can scavenge low level vibration energy and convert it into electrical power. It includes a fixed micro coil and a movable permanent magnet attached on a nickel planar spring integrated with silicon frame. The two-layer copper micro coil and nickel planar spring are fabricated using microelectroplating technique. Two prototypes with different coils and same magnet-spring system are assembled and tested. Prototype A can generate maximal load voltage of 51mV and load power of 5.89μW at 223.2Hz resonant frequency and 9.8m/s² acceleration. Similarly, at the resonant frequency of 247.5Hz, prototype B generates a maximum load power of 6.4μW and a load voltage of 62mV for acceleration of 9.8m/s². The coil´s area of 6.25 mm² in prototype B is only 28% of that of 22.56 mm² in prototype A, however, the load voltage and load power are increased 21.6% and 8.6%, respectively. The analysis about testing results is also given in this paper.