TY - JOUR
T1 - Air gap optimization for output power and band width in out-of-plane vibration energy harvesters employing electrets
AU - Asanuma, H.
AU - Hara, M.
AU - Oguchi, H.
AU - Kuwano, H.
PY - 2015/9/24
Y1 - 2015/9/24
N2 - We investigated the dependence of output power, frequency band width, and resonance frequency on the initial air gap for electret-based out-of-plane vibration energy harvesters, both numerically and experimentally. In this investigation, the external acceleration and surface charge densities of the electret were held constant. The numerical investigation predicted the following results: (1) an optimum value exists in the initial air gap to maximize the output power; and (2) enhanced electrostatic forces with decreasing the initial air gap emphasize the soft spring effect, which widens the frequency band width and lowers the resonance frequency. The experimental results showed behaviour consistent with the numerical predictions. The maximum output power in experiment was 4.0 μW at the optimum initial air gap of 0.43 mm when the external acceleration and the frequency were 4.9 m s-2 and 102 Hz, respectively. With reducing the initial air gap to 0.28 mm, the frequency band width increased to 17 Hz, a 2.6-fold increase over the optimum initial air gap. The peak output power at the initial air gap of 0.28 mm was 2.7 μW, when the external acceleration and frequency were 4.9 m s-2 and 96 Hz, respectively.
AB - We investigated the dependence of output power, frequency band width, and resonance frequency on the initial air gap for electret-based out-of-plane vibration energy harvesters, both numerically and experimentally. In this investigation, the external acceleration and surface charge densities of the electret were held constant. The numerical investigation predicted the following results: (1) an optimum value exists in the initial air gap to maximize the output power; and (2) enhanced electrostatic forces with decreasing the initial air gap emphasize the soft spring effect, which widens the frequency band width and lowers the resonance frequency. The experimental results showed behaviour consistent with the numerical predictions. The maximum output power in experiment was 4.0 μW at the optimum initial air gap of 0.43 mm when the external acceleration and the frequency were 4.9 m s-2 and 102 Hz, respectively. With reducing the initial air gap to 0.28 mm, the frequency band width increased to 17 Hz, a 2.6-fold increase over the optimum initial air gap. The peak output power at the initial air gap of 0.28 mm was 2.7 μW, when the external acceleration and frequency were 4.9 m s-2 and 96 Hz, respectively.
KW - air gap
KW - electret
KW - soft spring
KW - stainless steel
KW - vibration energy harvester
KW - wide band
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U2 - 10.1088/0960-1317/25/10/104013
DO - 10.1088/0960-1317/25/10/104013
M3 - Article
AN - SCOPUS:84947594705
VL - 25
JO - Journal of Micromechanics and Microengineering
JF - Journal of Micromechanics and Microengineering
SN - 0960-1317
IS - 10
M1 - 104013
ER -