자료유형  

 학위논문

Control Number  

0015492278

International Standard Book Number  

9781392352069

Dewey Decimal Classification Number  

333

Main Entry-Personal Name  

Liu, Zemin.

Publication, Distribution, etc. (Imprint  

[Sl] : Rensselaer Polytechnic Institute, 2019

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2019

Physical Description  

83 p

General Note  

Source: Dissertations Abstracts International, Volume: 81-06, Section: B.

General Note  

Advisor: Hella, Mona M.

Dissertation Note  

Thesis (Ph.D.)--Rensselaer Polytechnic Institute, 2019.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Restrictions on Access Note  

This item must not be added to any third party search indexes.

Summary, Etc.  

요약Energy harvesting has recently gained much attention for its potential to extend battery life or even to enable battery-less operation for Internet of Things (IoT) applications. However, the available power level for harvesting depends strongly on the type, and size of the energy harvester module, as well as the environment in which it is embedded. The problem is also exacerbated due to the sporadic and weak nature of the ambient energy.Various energy transducers require specific power interface to extract the maximum power. In order to provide a stable power supply to any wireless microsystem in an IoT scenario, the energy harvesting system itself has to be energy-efficient, has the proper interface, and can be reconfigured or adapted to optimize itself to work with various energy sources as they become available. This thesis focuses on the research and development for low-power, high efficiency RF/thermal single and hybrid energy harvesting systems.The basic RF energy harvesting system consists of an antenna, a matching network, an RF-DC rectifier and a voltage regulator. The variation of the input impedance of the rectifier with the RF input power level and the DC load condition is analyzed and simulated. A three-stage RF-DC energy converter with an adaptive impedance matching network is designed in 130-nm CMOS technology. A 5-bit successive-approximation register (SAR) analog-to-digital converter (ADC) samples the output voltage and feeds into a low-power digital control block to control a capacitor array in the integrated matching network. With a power consumption of 87.4 nW, the digital control block enables a wide frequency range of 220 MHz, which is the highest operational range reported to date, with a peak efficiency of 29.3% at a 915-MHz input frequency.A maximum power point tracking (MPPT) in the RF energy harvesting is achieved with the above-mentioned adaptive matching network. However, for a DC-DC boost converter based thermal energy harvesting system, the MPPT can be realized using a fractional open-circuit voltage (OCV) method. The transient behavior of the OCV sampling and converting phases are simulated and analyzed, and a reduced sampling time is achieved through the separate control of the two phases, providing a higher average conversion efficiency. The chip, fabricated in 180-nm CMOS technology, delivers a 1.8 V DC voltage with a conversion duty cycle of 0.998 and an improved average efficiency of 82.2%. The results are considered one of the highest reported conversion duty cycles compared to recent published results.Using the previous studies on individual RF and thermal energy harvesting systems, an RF/thermal hybrid energy harvester is presented. Noticing that one of the inputs to the general rectifier stage that is typically connected to the ground level, can come from intermediate rectifier stages or even be the DC output from other circuits, the rectifier in this case can be used as a combining stage for thermal and RF energy. This is done by feeding the boosted voltage from the thermoelectric generator (TEG) into the DC input of the rectifier, which tends to reduce the losses in the AC energy path. Individual MPPT is ensured by fractional-OCV method for the thermal energy and optimal output voltage control for the RF energy. The prototype fabricated in 180-nm CMOS technology achieves a peak end-to-end efficiency of 63.4% with a 915-MHz input RF power and an emulated TEG with 200-廓 internal resistance. With the efficiency of the RF-DC rectifier in consideration, the reported results are comparable to recent publications which only report the efficiency by emulating the RF-DC stage with an ideal voltage source.

Subject Added Entry-Topical Term  

Electrical engineering

Subject Added Entry-Topical Term  

Alternative energy

Added Entry-Corporate Name  

Rensselaer Polytechnic Institute Electrical Engineering

Host Item Entry  

Dissertations Abstracts International. 81-06B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:565439