Model and Experimental Research on an Electromagnetic Vibration-Powered Generator With Annular Permanent Magnet Spring

This paper presents a new electromagnetic vibration-powered generator. The input-output mathematical model of an axial magnetization annular permanent magnet spring is built. Taking advantage of the model, the characteristic curve of the magnetic force versus the displacement is obtained. Wires were wound both inside and outside of the annular permanent magnet to form an inner coil and an outer coil, respectively. The characteristic curve of the magnetic force, the natural frequency, the output voltage waveforms of the outer coil and the inner coil, and the magnetic field distribution of the designed generator have been simulated using the Finite Element method (FEM). Tests results of the output waveforms have good agreement with the simulation results. The maximum output power of the designed vibration-powered generator is 28.3 mW, and the open circuit RMS voltage is 5.1 V at an vibration frequency of 20 Hz and an amplitude of 5 mm.