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A piezoelectric energy harvester with backpressure pre-loaded is designed to investigate the performance that can be driven by the compressed air load in the pneumatic system. The power generation principle and microelement mechanics model are established, which can explain the principle that backpressure changes the internal energy of materials. The backpressure affects the internal stress of materials. The electromechanical coupling coefficient can be adjusted by the backpressure. The power generation obviously changes as the electromechanical coupling coefficient is adjusted. An experimental testing system is established, and the experimental results are analyzed to prove the effect of backpressure on the output power. There is a linear relationship between the peak voltage and backpressure. When the backpressure increases every 1 kPa, the voltage increases by 0.667 V. The voltage increment under backpressure is 5.13 times that without backpressure. The optimal output power is 12.3 mW in 30 kPa backpressure pre-load. The output power increases to the original 237% under the backpressure. The prototype can directly supply energy to the temperature sensor, and it can supply power to a magnetic switch with capacitor energy storage. [ABSTRACT FROM AUTHOR]

This paper describes an experimental study of compressed air energy harvesting by a piezoelectric energy harvester. We conducted parametric studies to evaluate the influence of different combinations of piezoelectric patches and the resulting energy output. We have demonstrated the rules for appropriate connection relationships. A peak output power of 0.65 mW occurred at the parallel connection type, and the peak voltage is 32.4 V. The results prove that the parallel connection is better than the series connection. As the number of parallel connections increases, the optimal load resistance decreases gradually. The output power becomes larger when the numbers of piezoelectric patches increase in the same condition. [ABSTRACT FROM AUTHOR]