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Yu H.,Chongqing University | Zhou J.,Key Laboratory for Optoelectronic Technology and Systems | Wang W.,National Key Laboratory of Fundamental Science of Micro Nano Device and System Technology
2014 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2014 | Year: 2014

The paper presents a new hybrid micro piezoelectric-electromagnetic generator for vibration energy harvesting, which generates energy from low frequency and small amplitude vibration environment, using piezoelectric and electromagnetic conversion mechanisms. The paper outlines factors needed when designing the hybrid energy harvester, including the coupling mathematical model, the finite element analysis, optimization procedure and trade-offs. The proposed hybrid energy harvester is also fabricated and experimental results show that the device can generate an open-circuit voltage of 4.32V and produce a power of 13.47μW with an optimal resistive load of 403KΩ at 0.1 m/s2 acceleration and 105.2 Hz frequency. © 2014 IEEE.


Yu H.,Chongqing University | Yang S.,Key Laboratory for Optoelectronic Technology and Systems | Wang W.,National Key Laboratory of Fundamental Science of Micro Nano Device and System Technology
2014 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2014 | Year: 2014

The paper proposes a complete energy harvesting solution integrated with a low-loss AC/DC rectifier and a high efficiency low dropout regulator (LDO) optimized for micro piezoelectric energy harvester. The AC/DC module converts AC into DC and then supplies power for the following LDO circuit module, through which the whole chip can obtain a stable 3.3V output voltage. A dynamic compensation mechanism is presented to improve the loop stability of LDO, which is easier to achieve high phase margin than traditional compensation strategy. The simulation results of LDO indicate that the typical dropout is 0.4mV with 1mA load current and 61mV with 150mA load current respectively, and the typical voltage line regulation error is 0.025%/V. In addition, the typical load regulation error was 0.00018%. The results demonstrate that the proposed chip meets the requirements of power supply for wireless sensor node (WSN). © 2014 IEEE.


Yu M.,Key Laboratory for Optoelectronic Technology and Systems | Wang S.,Chongqing University
Smart Materials and Structures | Year: 2010

A new composite magnetorheological elastomer (MRE) embedded with a copper coil was designed to induce a magnetic field inside and improve the field-dependent properties of the MRE. The composite MRE can avoid flux leakage, increase the utilization ratio of the magnetic field, and make magnetorheological equipment lightweight. A shearing stress-strain experiment for the composite MRE was carried out and the result showed that the composite MRE has a good magnetorheological effect. © 2010 IOP Publishing Ltd.


Yun J.,Southwest University | Yun J.,Chongqing University | Li P.,Chongqing University | Li P.,Key Laboratory for Optoelectronic Technology and Systems | And 2 more authors.
2011 International Conference on Multimedia Technology, ICMT 2011 | Year: 2011

An improved geodesic active contour model for the detection of object boundaries is presented. A geodesic active contour model is based on an active contour evolving in time. The geodesic active contour model has a serious weakness, that is, it stops at a local minimum where there is a deep concave boundary in an image. The generalized geodesic active contour model makes an active contour convergent to long, thin boundary indentations by introducing a shrinkage force. In this paper, we present an improved geodesic active contour model based on the generalized geodesic active contour with an error term. Experimental results show that the proposed model works successfully for concave objects, it can not only detect object boundaries, but also improve double rings. The convergence rate is faster, the robust is better than the generalized geodesic active contour model. © 2011 IEEE.


Yu H.,Chongqing University | Yu H.,Key Laboratory for Optoelectronic Technology and Systems | Yu H.,National Key Laboratory of Fundamental Science of Micro Nano Device and System Technology | Zhou J.,Chongqing University | And 3 more authors.
Sensors (Switzerland) | Year: 2014

To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT) for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si) solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

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