动态气体载荷下磁力辅助式压电俘能器设计与实验

Design and Experiment on Magnetic-assisted Piezoelectric Plate Harvester Excited by Dynamic Air Pressure

为了实现气动系统低功耗传感器的自供能需求,提出了一种新型磁力辅助式压电俘能器,以此提高俘能器俘获动态气体载荷能的效率。将磁铁间的非接触力作为磁力诱导的预应力施加在压电片中心,当动态气体载荷作用在压电片上时,磁力诱导的预应力可以通过改变压电片的位移来调节压电片表面正负电荷的分布,进而提高俘能器的机电转化效率。仿真研究表明,斥力诱导的预应力可增加俘能器的输出电压,而吸引力诱导的预应力则降低了俘能器的输出电压。采用外径22 mm、厚度0.23 mm的压电单晶片及缸径63 mm、行程150 mm的气缸制作实验样机,利用气动组件搭建测试系统。分别调节压力、周期、流量以及磁力等参数进行实验测试。实验结果表明,当俘能器的最佳匹配负载为0.87 MΩ时,最大的瞬时功率为1.39 m W,俘能器的最大瞬时功率提升12.6%,而引入磁力诱导的预应力仅为气体载荷的0.6%,磁力诱导预应力可有效提高俘能器俘获气动系统动态气体载荷能的效率。

In order to realize the demand of low power sensor for pneumatic system,a new type of magnetic-assisted piezoelectric energy harvester was proposed and it can promote the efficiency of harvesting the dynamic high air. The non-contact force between the magnets was used as magnetic induced pre-stress acted on the center of the piezoelectric circular diaphragm. The magnetic induced prestress can adjust the surface charge distribution of the piezoelectric circular diaphragm when the dynamic air pressure acted on the piezoelectric circular diaphragm. The simulation research showed that the repulsive force increased the output power of the magnetic-assisted piezoelectric plate harvester,while the attractive force decreased the output power of the magnetic-assisted piezoelectric plate harvester. The diameter and thickness of piezoelectric unimorph were 22 mm and 0. 23 mm,respectively. The diameter and distance of cylinder were 63 mm and 150 mm,respectively,and the prototype of the magneticassisted piezoelectric plate harvester was fabricated. The test system was built to research the rules and performances of the magnetic-assisted piezoelectric plate harvester. In the test,the pressure,cycle,flow and the magnets distances were adjusted. Experimental results showed that the instantaneous power was1. 39 m W when the optimal load resistance was 0. 87 MΩ,and the output power of the generator was promoted 12. 6%,while the magnetic induced pre-stress was only about 0. 6% of the hyperbaric air load.Therefore,the magnetic induced pre-stress can effectively improve the efficiency of the dynamic high air in the pneumatic system.