• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.215-223
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• 2015

Energy harvesting technique is an energy charging technique for communication device in energy-constrained environment. Recently, energy harvesting technique that harvests energy from wireless radio frequency signal is proposed. Representatively, there are time switching technique and power splitting technique. This paper proposes an optimal harvesting time allocation scheme in a wireless cognitive relay network when secondary user relay uses energy harvesting technique to transmit information. Secondary user relay receives information and energy simultaneously from the secondary user source's signal via time switching technique. We aim to maximize the instantaneous throughput by optimizing harvesting time of the secondary user relay. Simulation results show that using optimized harvesting time gets larger instantaneous throughput compared to using constant harvesting time.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.153-162
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• 2018

The importance of energy harvesting technique is increasing due to the elevated level of demand for sustainable power sources for wearable device applications. In this study, we developed an Energy Harvesting wearable Platform(EH-P) architecture which is used in the design of a multi-energy source based on TENG. The proposed switching circuit produces power with higher current at lower voltage from energy harvesting sources with lower current at higher voltage. This can powers microcontrollers for a short period of time by using PV and TENG complementarily placed under hard conditions for the sources such as indoors. As a result, the whole interface circuit is completely self-powered with this makes it possible to run of sensing on a Wearable device platform. It was possible to increase the wearable device life time by supplying more than 29% of the power consumption to wearable devices. The results presented in this paper show the potential of multi-energy harvesting platform for use in wearable harvesting applications, provide a means of choosing the energy harvesting source.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.6
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• pp.620-626
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• 2023

Energy harvesting technology, which converts wasted energy sources in everyday life into usable electric energy, is gaining attention as a solution to the challenges of charging and managing batteries for the driving of IoT sensors, which are one of the key technologies in the era of the fourth industrial revolution. Hybrid energy harvesting technology involves integrating two or more energy harvesting technologies to generate electric energy from multiple energy conversion mechanisms. In this study, a hybrid energy harvesting device called TMPPEG (thermo-magneto-piezoelectric-pyroelectric energy generator), which utilizes low-grade waste heat, was developed by incorporating PVDF polymer piezoelectric components and optimizing the system. The variations in piezoelectric output and thermoelectric output were examined based on the spacing of the clamps, and it was found that the device exhibited the highest energy output when the clamp spacing was 2 mm. The voltage and energy output characteristics of the TMPPEG were evaluated, demonstrating its potential as an efficient hybrid energy harvesting component that effectively harnesses low-grade waste heat.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.360-368
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• 2007

This paper is concerned with the development of piezoelectric energy harvesting device. Literature survey was carried out to investigate the state-of-art technology regarding piezoelectric energy harvesting method. It shows that the piezoelectric energy harvesting system has been researched as the needs for the auxiliary power system grow for ubiquitous sensor node. In this study, the piezoelectric energy harvesting system was constructed and the corresponding electric circuit was also built to investigate the power characteristics. Experimental results show that it can charge the small battery with ambient vibrations but still needs an effective mechanism to collect ambient energies.

• Smart Structures and Systems
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• v.18 no.3
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• pp.449-470
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• 2016

Energy harvesting is an emerging technique that extracts energy from surrounding environments to power low-power devices. For example, it can potentially provide sustainable energy for wireless sensing networks (WSNs) or structural control systems in civil engineering applications. This paper presents a comprehensive study on harvesting energy from earthquake-induced structural vibrations, which is typically of low frequency, to power WSNs. A macroscale pendulum-type electromagnetic harvester (MPEH) is proposed, analyzed and experimentally validated. The presented predictive model describes output power dependence with mass, efficiency and the power spectral density of base acceleration, providing a simple tool to estimate harvested energy. A series of shaking table tests in which a single-storey steel frame model equipped with a MPEH has been carried out under earthquake excitations. Three types of energy harvesting circuits, namely, a resistor circuit, a standard energy harvesting circuit (SEHC) and a voltage-mode controlled buck-boost converter were used for comparative study. In ideal cases, i.e., resistor circuit cases, the maximum electric energy of 8.72 J was harvested with the efficiency of 35.3%. In practical cases, the maximum electric energy of 4.67 J was extracted via the buck-boost converter under the same conditions. The predictive model on output power and harvested energy has been validated by the test data.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.3
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• pp.137-142
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• 2018

Energy harvesting technology is drawing attention as a means of collecting various eco-friendly energy and accumulating residual energy. Recently, differential power processing (DPP) is being developed as part of energy harvesting. This is being studied as a solution to the loss of power generation between power modules and the problems caused by module small losses depending on the size of power production. In this paper, we propose the necessity of the DPP by comparing and analyzing energy harvesting related module integration system and power supply efficiency of DPP. The power efficiency of the converter and the power difference between the wind power and the photovoltaic power supply have been changed to demonstrate the effectiveness of the proposed system.

• Smart Structures and Systems
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• v.21 no.3
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• pp.287-303
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• 2018

Applications of energy harvesting from mechanical vibrations is becoming popular but the full potential of such applications is yet to be explored. This paper addresses this issue by considering an application of energy harvesting for the dual objective of serving as an indicator of structural health monitoring (SHM) and extent of control. Variation of harvested energy from an undamaged baseline is employed for this purpose and the concept is illustrated by implementing it for active vibrations of a pipe structure. Theoretical and experimental analyses are carried out to determine the energy harvesting potential from undamaged and damaged conditions. The use of energy harvesting as indicator for control is subsequently investigated, considering the effect of the introduction of a tuned mass damper (TMD). It is found that energy harvesting can be used for the detection and monitoring of the location and magnitude of damage occurring within a pipe structure. Additionally, the harvested energy acts as an indicator of the extent of reduction of vibration of pipes when a TMD is attached. This paper extends the range of applications of energy harvesting devices for the monitoring of built infrastructure and illustrates the vast potential of energy harvesters as smart sensors.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.45-49
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• 2015

In this paper, we proposed not specturm sensing but also save energy without consume energy of secondary network that spectrum sensing of cognitive applied energy harvesting scheme. Algorithms of sensing and harvesting is determine active or idle of primary network, compares the amount of energy that is harvested by energy harvesting scheme with the threshold. If secondary network to send a message and primary network is active, by changing frequency to use the spectrum. Further, if secondary network have no message, continues energy harvest. Therefore, spectrum sensing applied energy harvesting scheme, energy of secondary network is remove waste and charge energy, efficiency and utilization of cognitive network can be increase.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.73-76
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• 2015

In this paper, we propose energy harvesting apply to spectrum sensing. In this case, we can be spectrum sensing without consume energy. Algorithms of sensing and harvesting are determine active or idle of primary network, Compares with the threshold energy and the amount of energy that is harvested by energy harvesting scheme. If the secondary network want to send a message while the primary network is active, secondary users will change frequency to use the spectrum. Further, if the secondary network has not message, it will continues harvest energy. Therefore, spectrum sensing applied the energy harvesting method, energy of secondary network is remove waste and charge energy. So, efficiency and utilization of cognitive network can be increase.

• International Journal of Aerospace System Engineering
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• v.2 no.1
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• pp.47-52
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• 2015

The transient phenomenon of self-powered energy-harvesting is assessed using a bond-graph method. The bond-graph is an energy-based approach to describing physical-dynamic systems. It shows power flow graphically, which helps us understand the behavior of complicated systems in simple terms. Because energy-harvesting involves conversion of power in mechanical form to the electrical one, the bond-graph is a good tool to analyze this power flow. Although the bond-graph method can be used to calculate the dynamics of combining mechanical and electrical systems simultaneously, it has not been used for harvesting analysis. We demonstrate the usability and versatility of bond-graph for not only steady analysis but also transient analysis of harvesting.