A low frequency piezoelectric energy harvester with trapezoidal cantilever beam: theory and experiment

With the development of low power MEMS device and outdoor wireless sensor network, new energy supply has been a key to replace the traditional energy which has some disadvantages. We have found that obtaining energy from the daily low frequency vibration environment is a very efficient solution to ease the pressure of energy sources. In this paper, a utility low frequency piezoelectric energy harvester with trapezoidal cantilever beam is presented. Then, a relevant theoretical model, optimization method and comparison experiment are made. The results show that the theoretical analysis results are in agreement with the experimental results; under the condition of constant beam length, open-circuit voltage and output power of the trapezoidal beam piezoelectric energy harvester are 81.6 and 167% more than those of the rectangular beam piezoelectric energy harvester. In addition, In order to further broaden the frequency band and improve output characteristics, we use the nonlinear method to redesign the experiment based on the above experiments. The results show that distance and magnet polarity change have an important effect on output characteristics.