Characteristics of Electric Energy Conversion in Pneumatic System Based on Piezoelectric Generator

This paper reports the development of a high load-carrying capacity piezoelectric generator (PG) to harvest the great amount of compressed air energy wasted by the moving cylinder in a pneumatic system. The PG is designed to convert the pressure energy induced by compressed air into electrical energy. The coupling model of the piezoelectric patch is established under pressure motivation. The relationship between the output voltage and the piezoelectric patch deformation has been analyzed, and the output voltage is calculated through the simulation model. The simulation result demonstrates that the output voltage is 72.00 V when the load resistance is 1,000 kΩ. The prototype generator consists of a chamber and a piezoelectric patch, which is sealed at the bottom. The prototype is installed in a real pneumatic system to test energy conversion performance, and it is driven by the compressed air that can be influenced by the moving piston. The energy exchange capacity of the proposed PG is analyzed by testing the output voltage and power generated under real working conditions. The test results show that the output voltage is increased when the moving distance decreases. The maximal output voltage and power are 72.80 V and 7.77 mW, respectively. The analysis of the testing results shows that the energy exchange capacity of the PG is highly relevant to the piston moving distance.