Browsing by Author "Tseng, Chia-Yuan"

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A Magnetic/Piezoelectric-Based Thermal Energy Harvester
(2013)
Chung, Tien-Kan
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Shukla, Ujjwal
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Tseng, Chia-Yuan
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Chen, Chin-Chung
;
Wang, Chieh-Min
In this paper, we demonstrate a non-contact magnetic/piezoelectric-based thermal energy harvester utilizing an optimized thermal-convection mechanism to enhance the heat transfer in the energy harvesting/converting process in order to increase the power output. The harvester consists of a CuBe spring, Gadolinium soft magnet, NdFeB hard magnets, frame, and piezoelectric PZT cantilever beams. According to the configuration, the energy harvesting/converting process under a temperature-difference is cyclic. Thus, the piezoelectric beams continuously oscillate and subsequently produce voltage responses due to the piezoelectric effect. The maximum voltage response of the harvester under a temperature-difference of 25 degrees C is 16.6 mV with a cycling frequency of 0.58 Hz. In addition, we compare the testing result of the harvester utilizing the new thermal-convection mechanism reported in this paper and using previous thermal-convection mechanism reported elsewhere. According to the comparison, the results show the harvester utilizing the new thermal-convection mechanism has a higher cycling frequency resulting in a higher power output than the previous mechanism.
A MICRO KINETIC ENERGY HARVESTER DEMONSTRATING ENERGY HARVESTING FROM 3-D MECHANICAL MOTION AND POWER INCREASING THROUGH MAGNETIC-BASED FREQUENCY RECTIFICATION
(2012)
Chung, Tien-Kan
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Wang, Chieh-Min
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Tseng, Chia-Yuan
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Liu, Tzu-Wei
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Yeh, Po-Chen
In this paper, we report a micro 3-D kinetic energy harvester demonstrating an energy conversion from environmental mechanical-energy (3-D mechanical motion) to electrical energy (voltage output). In addition to energy harvesting/conversion from 3-D motion, we demonstrate a non-contact frequency-up rectification approach which converts an incoming lower vibration frequency to a higher frequency in order to increase the power output of the harvester.
A Miniature Magnetic-Piezoelectric Thermal Energy Harvester
(2015-07-01)
Chen, Chin-Chung
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Chung, Tien-Kan
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Tseng, Chia-Yuan
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Hung, Chiao-Fang
;
Yeh, Po-Chen
In this paper, we report a miniature thermal energy harvester with a novel magnetic-piezoelectric design. The harvester consists of a soft magnetic Gd cantilever beam, a piezoelectric lead zirconate titanate sheet, an NdFeB hard magnet, silicon clamps, and a silicon frame. In this design, the harvester is driven by a temperature difference between a cold side and room temperature ambient air, unlike other magnetic-piezoelectric thermal energy harvesters that are driven by a temperature difference between a cold side and a hot side or between two hot sides. Experimental results show that with a temperature difference of 20 degrees C (cold side: 6.7 degrees C, hot side: 26.7 degrees C), the harvester produces a maximum peak-to-peak voltage of 37 mV and a root mean square voltage of 1.98 mV. The estimated maximum instantaneous power density and average power density is 21.7 nW/cm(3) and 62.9 pW/cm(3), respectively. Moreover, the total volume of our harvester (length x width x height: 6 x 3.5 x 3 mm) is 217 times lower than that of previous experimental harvesters and 38 times smaller than that of previous theoretical-modeled harvesters. Therefore, our harvester is the smallest machined magnetic-piezoelectric thermal energy harvester designed to date. These features enable our harvester to be more easily implemented and integrated with micro wireless sensors and thereby increase more self-powered wireless-sensing applications.
A Novel Miniature Thermomagnetic Energy Harvester
(2014)
Chen, Chin-Chung
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Chung, Tien-Kan
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Cheng, Chi-Cheng
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Tseng, Chia-Yuan
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機械工程學系
Nowadays, thermal-energy-harvesting is an important research topic for powering wireless sensors. Among numerous thermal-energy-harvesting approaches, some researchers demonstrated novel thermomagnetic-energy harvesters to convert a thermal-energy from an ambient temperature-difference to an electrical-output to power the sensors. However, the harvesters are too bulky to be integrated with the sensors embedded in tiny mechanical-structures for some structural-health-monitoring applications. Therefore, miniaturized harvesters are needed. Hence, we demonstrate a miniature thermomagnetic-energy harvester. The harvester consists of CuBe-beams, PZT-piezoelectric-sheet, Gd-soft-magnet, NdFeB-hard-magnet, and mechanical-frame. The piezoelectric-sheet and soft-magnet is bounded at fixed-end and free-end of the beams, respectively. The mechanical-frame assembles the beams and hard-magnet. The lengthxwidthxthickness of the harvester is 2.5cmx1.7cmx1.5cm. According to this, our harvester is 20-times smaller than the other harvesters. In the initial-state of the energy-harvesting, the beams\' free-end is near the cold-side. Thus, the soft-magnet is cooled lower than its curie temperature (Tc) and consequently changed from paramagnetic to ferromagnetic. Therefore, a magnetic-attractive force is produced between the soft-magnet and hard-magnet. Consequently, the beams/soft-magnet are down-pulled toward the hard-magnet fixed on the hot-side. The soft-magnet closing to the hot-side is heated higher than its Tc and subsequently changed to paramagnetic. Consequently, the magnetic-force is eliminated thus the beams are rebounded to the initial-state. Hence, when the harvester is under a temperature-difference, the beams\' pulling-down/back process is cyclic. Due to the piezoelectric effect, the piezoelectric-sheet fixed on the beams continuously produces voltage-response. Under the temperature-difference of 29 C, the voltage-response of the harvester is 30.4 mV with an oscillating-frequency of 0.098 Hz.
A Three-Axial Frequency-Tunable Piezoelectric Energy Harvester Using a Magnetic-Force Configuration
(2014-09-01)
Chung, Tien-Kan
;
Wang, Chieh-Min
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Yeh, Po-Chen
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Liu, Tzu-Wei
;
Tseng, Chia-Yuan
To date, researchers have utilized energy harvesters to power wireless sensor nodes as self-powered wireless sensors to create many innovative wireless sensors network applications such as medical monitoring, machining-condition monitoring, and structural-health monitoring. Regarding to energy harvesters, some researchers demonstrated wideband or frequency up-converted vibrational energy harvesters using magnetic force together with piezoelectric materials. However, these harvesters are not able to harness 3-D or three-axial mechanical energy through using one single mechanism or configuration. To address this problem, we report a novel magnetic-force-configured three-axial frequency-tunable piezoelectric energy harvester in this paper. Due to the magnetic-force configuration, the harvester converts ambient three-axial mechanical vibration/motion to piezoelectric voltage-response (i.e., three-axial energy harvesting). Simultaneously, the harvester also converts the ambient vibration/motion at a lower frequency to higher frequency without mechanical wear-out (i.e., noncontact frequency up-conversion). Through modifying the configuration, the oscillating frequency is tunable. By frequency tuning, the harvester\'s oscillating frequency and ambient vibration frequency are able to be matched to maximize the power output. Experimental results show the peak voltage, peak power, and frequency conversion of one single piezoelectric beam of the harvester under an in-plane and out-of-plane vibration is up to 800 mV, 640 nW, and from 7 to 56 Hz, and 27 mV, 729 pW, and from 1 to 294 Hz, respectively. These results confirm the harvester is capable of harnessing energy from 3-D and three-axial mechanical motion/vibration, addressing frequency-mismatching issue, avoiding mechanical wear-out problems, and producing a stable voltage output. Due to these, the energy-harvesting approach will enable more novel and practical wireless sensors network applications in the future.
An Electromagnetic-Induction Approach for Screw-Hole Targeting in Interlocking-Nail Surgery
(2012)
Chung, Tien-Kan
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Chu, Hou-Jen
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Wong, Tze-Hong
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Hsu, Wensyang
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Lee, Meng-Shiue
We report a novel approach for targeting screw-holes of an intramedullary nail in a long-bone fracture surgery. The approach utilizes the electromagnetic induction to avoid over exposure of radioactivity which is the critical issue in conventional X-ray-imaging targeting method. Based on the approach, we fabricate a targeting system. The targeting system consists of a c-shaped electromagnet, detecting-coil, guiding-mechanism, and measurement electronics. When a voltage is applied to the electromagnet, magnetic flux is generated in the air gap of the electromagnet and subsequently detected by the coil. When the flux is detected by the coil, a voltage response is induced in the coil. When a nail in a bone is scanned through the air gap of the electromagnet, the flux is influenced due to a discrepancy of the permeability between the location with and without the hole of the nail. The influenced flux induces different voltage response in the coil. Through analyzing the voltage response, we establish a criterion for targeting the holes. By the criterion, the experimental result shows the maximum error of targeting a hole with a diameter of 5 mm is less than 2.5 mm.
DESIGN, FABRICATION, AND TESTING OF A THERMAL/MECHANICAL/MAGNETIC HYBRID ENERGY MICRO-HARVESTER
(2012)
Chung, Tien-Kan
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Tseng, Chia-Yuan
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Chen, Chin-Chung
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Wang, Chieh-Min
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機械工程學系
In this paper, we report a novel hybrid energy micro-harvester. The harvester utilizes ferromagnetic materials combined with piezoelectric cantilever beams to harvest the energy from a thermal, mechanical, and magnetic energy sources and subsequently convert the energy to an electrical output. In addition to energy-harvesting, the harvester utilizes a non-contact approach in its structure to avoid the wear problem which frequently occurs in conventional structural-contact approaches.