摘要
考虑现有旋转发电机无法适应高/匀速旋转运动且振动冲击/噪音大、可靠性低等弊端,提出了一种由旋转磁铁激励的压电俘能器,并从理论及试验两方面研究了旋转磁铁数量(间距)对激振力及压电振子发电特性的影响规律。结果表明,在其它条件确定的情况下,存在使激振力最大的最佳旋转磁铁间隙比(磁铁直径与相邻磁铁间距离之比);间隙比为2时的激振力幅值为间隙比为0和4时的6.2倍。采用2,12,24个旋转磁铁激励发电时,电压-转速特性曲线中均存在多个使输出电压出现峰值的最佳转速,其中最大峰值电压及其所对应的最佳转速分别为29.4,87.2,28.4V和1 282.5,707.5,2451r·min-1;12个旋转磁铁激励的最大输出电压为其它两种情况的3倍。此外,压电振子一次激励所生成电能(波形数量及幅值)还与旋转磁铁数量及转速有关。2个旋转磁铁在低转速时仅能激励出1个较大幅值电压波形,而高转速时可生成4个幅值较大的自由振荡波形;12个磁铁在任何转速下都仅能激励出1个电压波形。实验显示动磁铁数量是影响旋转压电俘能器发电量及输出功率的关键要素。
As existing rotating generators can not adapt to a high speed shock and vibration and have higher noise and lower reliability,this paper proposes a piezoelectric energy harvester excited by rotating magnets.The influence of the number of the rotating magnets（NRMs）on the exciting force as well as the output voltage of the piezoelectric harvester is investigated theoretically and experimentally.The results show that there is an optimal gap ratio（the gapλlbetween two adjacent magnets to the magnet diameter）for the excitation force to achieve maximum.The obtained excitation force a tλl=2 is 6.2 times that atλl=0 and λl=4.When the voltage generation exited with 2,12,24 rotating magnets in the experiments,there are several optimal rotating speeds for the generated voltages to achieve the peak.The maximal peak voltages and the relative optimal speeds for 2,12,24 rotating magnets are 29.4,87.2,28.4V and 1 282.5,2 707.5,2 451r·min-1,respectively.Themaximal voltage generated under 12 rotating magnets is about 3 times those under other excitation conditions.The voltage waveform generated from the piezoelectric harvester under one excitation depends on the NRMs and rotating speeds.For 2 rotating magnets,the number of voltage waveforms generated at low and high rotating speeds are 1 and 4,respectively.For 12 rotating magnets,only one voltage waveform generates at any speed.These results demonstrate that the NRMs have great influence on energy generation and output powers of piezoelectric energy harvesters.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2014年第7期1864-1870,共7页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.51277166
No.51377147
No.51075371)
浙江省新苗人才计划资助项目(No.2013R404066
No.2013R404071)
关键词
压电俘能器
旋转激励
磁铁间距
输出电压
piezoelectric energy harvester rotating excitation Number of Rotating Magnets（NRMs） generated voltage
