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외팔보 및 양단고정보 형태의 압전 발전시스템 발전량 비교
김선중(Sun Jung Kim),송예원(Yewon Song),황성주(Sung Joo Hwang),안정환(Jung Hwan Ahn),김정훈(Jeong Hun Kim),성태현(Tae Hyun Sung) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.4
In this study, we compared a cantilever piezoelectric energy harvester with a fixed-fixed piezoelectric energy harvester and analyzed the output powers of two harvesters. In two harvesting systems, the same piezoelectric material was used for giving identical condition. In order to exert input energy, we fell steel balls on the piezoelectric harvester. The weights of steel balls were 2g and 4g. The cantilever piezoelectric energy harvester generated the maximum power of 6.494 mW with a 4g steel ball and the fixed-fixed piezoelectric energy harvester produced the maximum power of 8.934 mW. The fixed-fixed piezoelectric energy harvester produced higher maximum power than the cantilever one in all cases. The results shows that 33-mode is more dominant than 31-mode.
부하연결에 따른 외팔보 압전에너지 하베스터의 공진주파수 변화 해석
황성주(Sung Joo Hwang),안정환(Jung Hwan Ahn),김선중(Sun Jung Kim),김정훈(Jeong Hun Kim),송예원(Yewon Song),성태현(Tae Hyun Sung) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.4
Piezoelectric cantilever beam is used in conversion of mechanical energy to electrical energy, and vice versa. But, when an external load connected to piezoelectric material, mechanical characteristic of cantilever beam is changed. We study resonance frequency shift of the piezoelectric cantilever beam according to load connection. When the external circuit changed from open to short, resonance frequency of the piezoelectric cantilever beam is changed from 40 Hz to 39 Hz. Also, displacement of the free end of the piezoelectric cantilever beam increased 2.4%. After then, we optimize resistive impedance matching for maximum power transfer. In matching case, resonance frequency is located between open and short circuit connection. Free end displacement also 21.4% decreased. This result shows that electrical load connection results in changing of mechanical characteristic like stiffness, resonance frequency, displacement.
김정훈(Jeong Hun Kim),황성주(Sung Joo Hwang),안정환(Jung Hwan Ahn),홍성광(Seong Kwang Hong),김선중(Sun Jung Kim),송예원(Yewon song),성태현(Tae Hyun Sung) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.4
Nowadays, enhancement of output power of piezoelectric energy harvesting is actively conducted. We study strain of piezoelectric energy harvester induced by magnets. We supply constant input using a function generator and a vibration exciter. Under a constant mechanical vibration input, we match impedance between piezoelectric material and the load resistor. Thereafter we measure electrical output of piezoelectric cantilever beam. We measure the resonance frequency and the output voltage of an open circuit while the distance between the magnets changes; 2, 5, 8, 10, 15 mm. As the distance between the magnets decreases it shows a higher resonance frequency and output voltage. In the case of an open circuit and vibration frequency of 71 Hz, output voltage was measured 16.6 Voc. Load impedance was matched at 17 kΩ, in such conditions the output voltage and power were measured to be 10.9 Vrms and 6.98 mW.