Development of a rotary electromagnetic microgenerator

This study presents the development of an in-plane rotary electromagnetic microgenerator, which consists mainly of a multilayer planar copper ( Cu) microcoil and a multipolar hard magnet made of NdFeB, the whole volume of which is approximately 5 x 5 x 2 mm(3). The study focuses on the design and manufacturing required to obtain a high power generation output, and an analytical model is developed to predict the power output for different designs of microgenerators. The geometric pattern design of the Cu planar microcoil is manufactured using the filament winding method. Both the linewidth and spacing of the microcoil are 30 mu m. The multipolar hard NdFeB magnet is molded and sintered, and a specially designed piece of equipment ( a yoke) is used to magnetize the NdFeB magnet to produce an external magnetic field. After magnetization, an anisotropic residual induction ( B(r)) of 1.44 tesla is produced. The theoretical model of this power microgenerator is evaluated and compared with experimental results, and it is found that the analytical simulation shows a good agreement with the experimental results. The induced electromotive force ( EMF) is 111.2 mV and a maximum power output of 0.412 mW at a frequency of 149.3 Hz is obtained.