Design of a Piezoelectric Energy Harvester with Elastic Amplification

Vibration energy is a kind of renewable energy which is not affected by climate. Vibration energy harvesting is also one of the common methods to harvest environmental energy, and obtaining energy from walking is a practical and convenient way. In this paper, the traditional simply supported beam structure is improved, and the elastic amplification structure is added at the end of the simply supported beam. A piezoelectric energy harvester with elastic amplification for human energy harvesting is designed. The results show that in a certain range, the spring stiffness and external force have a great influence on the resonance frequency and the output electric energy. At the same time, the length of the piezoelectric beam and the weight of the mass will also affect the output electric energy. When the excitation frequency in the range of 3-4Hz (walking frequency) , the maximum output power of the piezoelectric energy harvester with elastic amplification is about 8.15mW, and the output power per unit volume of the piezoelectric beam is about 6.17 μW/mm3, which is 123% higher than the simply supported beam under the same structure. The experimental results show that the power generated by the piezoelectric energy harvester with elastic amplification is enough to charge low-power products.