Rf Energy Harvesting For Wireless Communication Systems: Statistical Models For Battery Recharging Time

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2014Thesis (M.Sc.) -- İstanbul Technical University, Instıtute of Science and Technology, 2014Yeni bir enerji kaynağı olarak nitelenebilecek olan enerji hasatlama sistemleri, enerji kullanan her cihazın çevrede bulunan mevcut enerji kaynaklarını kullanarak, enerji bakımından kendi kendine yetmesi olarak açıklanabilir. Özellikle düşük güç harcayan cihazlarla kullanıldığında enerji hasatlama bütünleyici bir çözüm olarak ortaya çıkmaktadır. Elektromanyetik frekans spektrumunun bir bölümü olan radyofrekans (RF) işaretleri de, haberleşme sistemleri için enerji hasatlama yapılabilecek enerji kaynaklarından biridir. Bu tezde, RF işaretinden enerji hasatlama konusu ele alınmakta ve RF işaretinden enerji hasatlama sistemlerinde pil şarj zamanının istatistiki olarak nitelenmesi üzerine bir çalışma yapılmaktadır.Energy harvesting systems contribute to energy requirements of low-power devices as renewable energy sources. Radio frequency (RF) signal energy can be used as an energy source for energy harvesting systems. The RF signal energy available in the medium is received by the antenna of RF energy harvesting system, and converted to DC signal energy to power the electrical device. In this thesis, RF energy harvesting is emphasized for providing energy to wireless communication devices. Moreover, the distributions of battery recharging time are characterized for various wireless channel models.Yüksek LisansM.Sc

Design of an efficiency-enhanced Greinacher rectifier operating in the GSM 1800 band by using rat-race coupler for RF energy harvesting applications

Radio frequency energy harvesting (RFEH) circuits can convert the power of communication signals from radio frequencies (RF) in the environment into direct current and voltage (DC power). In this study, the Greinacher full-wave rectifier circuit topology was combined with a 180 hybrid ring (rat-race) coupler which was a passive RF/microwave circuit. Thus, higher RF-DC conversion efficiency was obtained. First, using the Greinacher rectifier topology, RFEH circuit operating at the center frequency of 1850 MHz was designed. Then, at this frequency, designing of the rat-race coupler having 1000 MHz bandwidth was made. The S-parameter measurements and simulation data of the designed coupler circuit were compared. Finally, the high efficiency rectifier circuit where these two circuits were used together was designed. The proposed rectifier circuit was constructed on 70 × 70 × 1.6 mm3 FR4 substrate material with a permittivity of 4.3 (εr = 4.3). The power conversion efficiency (PCE) of the rectifier circuit, which had 125 MHz bandwidth at the center frequency of 1850 MHz and was developed with rat-race coupler, was calculated as 71% at 4.7 dBm input power. In addition, with this study, at −15 dBm input power, which was a relatively low power level, 40% PCE value was obtained

Application of thermal energy harvesting from photovoltaic panels

This paper describes a newly developed system for harvesting thermoelectric energy from photovoltaic panels. This system helps to power monitoring systems for photovoltaic panels (PVs) in locations where there is no energy source using waste thermal energy from PVs exposed to the sun’s rays. In the study described here, the thermal energy from a PV panel was captured and transferred to a thermoelectric generator (TEG). A temperature gradient was created by reducing the temperature using an aluminium heat sink in ambient weather conditions. This temperature gradient was used to generate electricity via two TEGs. In field tests carried out in April, in Aksaray province in central Turkey, the maximum temperature gradient due to solar radiation was measured as 21.08 °C. The harvested energy was increased to a usable level of 4.1 V using a DC-to-DC converter and stored in a li-ion rechargeable battery. The maximum charge current level of the battery was 147 µA. The maximum harvested energy was 458.64 mW, and a stable level of around 350 mW was achieved. The experimental operation of the prototype system was carried out in stable weather conditions; however, weather and climatic conditions greatly affect levels of energy harvested as a result of changing temperature gradients. The energy obtained with the prototype may reduce the battery maintenance costs of PV monitoring systems and lead to the development of new such systems which cannot presently be used due to a lack of energy

Compact rectenna design for RF energy harvesting applications RF enerji hasatlama uygulamaları için kompakt doğrultuculu anten (rectenna) tasarımı

xxiv, 76 sayfa29 cm. 1 CDABSTRACTIn this study, a detailed literature study has been conducted about radio frequency energy harvesting systems, and two different RF energy harvesting system designs are presented operated two different bands. RF energy harvesting systems have been in our lives for more than fifty years. The number of studies carried out on these systems has increased, especially to meet the power requirements of low power consumption devices whose usage is growing with the developing technology in recent years. In the literature, RF energy harvesting systems have been generally designed to operate in the ultra-high-frequency band. For this purpose, two different RF energy harvesting systems operating in this frequency band have been developed. While determining the operating frequencies of the proposed systems, GSM and ISM bands widely used have been preferred. The RF energy harvesting system consists of a receiving antenna, a rectifier circuit that converts RF signals into DC signals, and an impedance matching circuit between the antenna and rectifier circuit.ÖZETBu çalışmada, radyo frekans enerji toplama sistemleri hakkında detaylı bir literatür çalışması gerçekleştirilmiş ve iki farklı bantta çalışmak üzere tasarlanan iki farklı RF enerji toplama sistemi tasarımı sunulmuştur. RF enerji hasatlama sistemleri elli yıldan uzun bir süredir hayatımızda yer almaktadır. Bu sistemler ile ilgili yürütülen çalışmaların sayısı özellikle son yıllarda gelişen teknoloji ile birlikte kullanımı artan düşük güç tüketimi olan cihazların güç ihtiyacını karşılamak amacıyla artmıştır. Literatürde bulunan RF enerji hasatlama sistem tasarımları genellikle ultra yüksek frekans bandında çalışmaktadır. Bu amaçla bu frekans bandında çalışan iki adet farklı RF enerji hasatlama sistem tasarımı oluşturulmuştur. Önerilen sistemlerin çalışma frekansları belirlenirken ise kullanımları oldukça yaygın olan GSM ve ISM bantları tercih edilmiştir. RF enerji hasatlama sistemi alıcı anten, RF sinyalleri DC sinyallere dönüştüren doğrultucu devre ve anten ile doğrultucu devre arasında bulunan empedans eşleştirme devresinden oluşmaktadır

Triboelektrik nanojeneratörler : biyomekanik enerji hasatlama, kendi gücünü sağlayan sensörler ve giyilebilir uygulamalar

Cataloged from PDF version of article.Thesis (M.S.): Bilkent University, Department of Materials Science and Nanotechnology, İhsan Doğramacı Bilkent University, 2017.Includes bibliographical references (leaves 58-74).One of the biggest challenges ahead massive advancement of electronic tech-nology is increasing energy consumption. A closer consideration on draining of fossil reserves and rapid development of wearable and portable consumer elec-tronics, inevitable paradigm shift is required towards use of renewable energy sources and self-powered electronic systems respectively. In parallel to this con-sideration, triboelectric nanogenerators have emerged to scavenge energy from ambient environment by using ubiquitous phenomenon of triboelectricity or con-tact electrification in other words. Essentially, triboelectric nanogenerators har-vest mechanical energy into electricity by utilizing triboelectric charge generation and electrostatic induction phenomenon. Accordingly, we developed high perfor-mance biomechanical energy harvesting floor tiles to scavenge human motions into electricity and electrode core-polymer shell structured triboelectric nanogen-erator fibers for wearable applications. Furthermore, new perspectives are intro-duced for fabrications of low-cost, mass producible, large area and flexible tribo-electric nanogenerator structures.by Ahmet Faruk Yavuz.M.S

Multi-band radio frequency energy harvesting

Cep telefonları, Wi-Fi gibi kablosuz haberleşme cihazlarının kullanımındaki büyük artışa paralel olarak ortamda mevcut olan elektromanyetik dalgaların varlığı da önemli ölçüde artmıştır. Enerji hasadı olarak adlandırılan ortamda az miktarda bulunan bu enerjinin toplanarak kullanılabilir elektrik enerjisine dönüştürülmesi olayı son zamanlarda büyük ilgi görmeye başlamıştır. Bu ilgideki en büyük etken düşük güç tüketen cihazların yaygın olarak kullanılmaya başlanması ve bunların sürekli olarak enerjiye ihtiyaç duymasıdır. Bu ihtiyaç düşük güçlü enerji elde etme çalışmalarında artışı da beraberinde getirmiştir. Bu tezde, çok bantlı RF enerji hasatlama devresi tasarlanmıştır. 900 MHz, 1800 MHz ve 2450 MHz frekanslarında oluşturulmuş sistemin çıkış gerilimi ve verimi ortaya konmuştur. Bu tezdeki tüm simülasyonlar ADS (Advance Design System) 2017 programı kullanılarak yapılmıştır. Öncelikle iki kademeden on iki kademeye kadar olan çok kademeli DVM (Dickson Voltage Multiplexer) tasarlanmıştır. Her bir frekans için maksimum gücü veren yük dirençleri tespit edilmiş ve her üç frekans için de uygun olan ortak yük seçilmiştir. Daha sonra, iki Schottky diyot modelli (HSMS-2852) iki kademeden altı kademeye kadar olan çok kademeli DVM tasarımında maksimum çıkış gücünü elde edebilmek için bu devrelere LC, LL ve π tipi empedans eşleme devreleri uygulanmıştır. Her bir eşleme tipi için her bir frekansa ait maksimum çıkış gücünü veren kademe sayıları belirlenmiştir. Her bir eşleme tipi için 900 MHz, 1800 MHz ve 2450 MHz frekanslarında elde edilen kademe sayılarına sahip bu üç devre birleştirilmiştir. Sonuç olarak her bir eşleme tipi için ortaya çıkan sistemin çıkış gerilimi ve verimi analiz edilmiştir.In parallel with the great increase in the use of wireless communication devices such as mobile phones and Wi-Fi, the presence of electromagnetic waves in the environment has increased significantly. The phenomenon of collecting this small amount of energy in the environment called energy harvesting and converting it into usable electrical energy has recently attracted great interest. The biggest factor in this interest is the widespread use of low-power devices and their constant need for energy. This need has brought about an increase in low-power energy acquisition studies. In this thesis, a multi-band RF energy harvesting circuit is designed. The output voltage and efficiency of the system built at 900 MHz, 1800 MHz and 2450 MHz frequencies have been demonstrated. All simulations in this thesis were made using the ADS (Advance Design System) 2017 program. Firstly, the multi-stage DVM (Dickson Voltage Multiplier), ranging from two to twelve stages, was designed. The load resistances giving the maximum power for each frequency were determined and a common load suitable for all three frequencies was selected. Then, LC, LL and π type impedance matching circuits were applied to these circuits in order to obtain maximum output power in multi-stage DVM design with two Schottky diode models (HSMS-2852) from two stages to six stages. The number of steps giving the maximum output power for each frequency is determined for each matching type. These three circuits with the number of steps obtained at the frequencies 900 MHz, 1800 MHz and 2450 MHz are combined for each matching type. The output voltage and efficiency of the resulting system were analyzed for each matching type