A high-efficiency, self-powered nonlinear interface circuit for bi-stable rotating piezoelectric vibration energy harvesting with nonlinear magnetic force
Affiliations: [a] Science and Technology on Integrated Logistics Support Laboratory, National University of Defense Technology, Changsha, Hunan, China | [b] Faculty of Engineering and the Environment, University of Southampton, Boldrewood Campus, Southampton, UK
Correspondence:
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Corresponding author: Zhongsheng Chen, Science and Technology on Integrated Logistics Support Laboratory, National University of Defense Technology, Changsha, Hunan 410073, China. Tel.: +86 731 84574322; Fax: +86 731 84573395; E-mail:[email protected]
Abstract: Parallel synchronized switch harvesting on inductor
(P-SSHI) circuits have been proved to enhance piezoelectric vibration energy
harvesting (PVEH), but the maximum conversion efficiency is obtained only
when the voltage across the storage capacitor (VSC) equates to the optimal
value. For bi-stable rotating PVEH with nonlinear magnetic force in
engineering applications, however, the VSC will change greatly when powering
real electric loads, thus it is impossible to maintain high conversion
efficiency. In order to solve this problem, this paper presents an improved
P-SSHI circuit with controllable optimal voltage (COV-PSSHI) by using a
voltage control strategy between the storage capacitor and the electric
load. The innovation is to control and maintain the VSC close to the optimal
value. Firstly, the COV-PSSHI circuit is proposed and its theoretic model is
built in detail. Then its average harvested power (AHP) is theoretically
derived and AHP of the COV-PSSHI circuit is proved to be more than that of a
classical P-SSHI circuit. In the end, experiments are performed to validate
the performance of the COV-PSSHI circuit. It can be seen that the COV-PSSHI
circuit can increase the AHP by factor 1.25 compared with classical P-SSHI
circuits, which is enough to intermittently power the wireless sensor node.
Also power consumption of the voltage control circuit has few effects on the
COV-PSSHI circuit. In particular, it needs to optimize the envelop
capacitor, the parallel inductor and two threshold voltages of the voltage
controller in order to implement the COV-PSSHI circuit well in practice.
