Abstract: To meet the demands of rotating machine monitoring system for self-power, a novel piezo-cantilever generator excited by the coupling effect between rotating magnets and those fixed on the piezo-cantilever is presented. To obtain the influence of rotating speed of magnet/duration of exciting and period-ratio(duration of exciting to exciting period) on the response performance of piezo-cantilever(waveform and amplification factor), a dynamic response model for the piezo-cantilever under magnetic impact force established and simulated. The analytical results show that the magnetic force is pulse load for low rotating speed. While, the magnetic force belong to period load for high rotating speed. In this case, there are multiple optimal rotating speeds for the piezo-cantilever to achieve maximal amplification factor. Furthermore, there is an optimal rotating speed under given period-ratio(or an optimal period-ratio under given rotating speed) for the amplification factor to achieve peak. On the bases of theoretical research, piezo-cantilever generators were fabricated and tested to obtained influence of rotating speed, magnet thickness, and end-mass of the piezo-cantilever on the generated voltage. The test results show the feasibility of the novel piezo-cantilever generator and validity of theoretical results. Besides, the effective speed-band for real-time self-powering can be enhanced with increasing magnetic force or the number of piezo-cantilevers with different natural frequencies.

Key words: piezoelectric;energy generation;rotating excitation