Preparing the books to read every day is enjoyable for many people. However, there are still many people who also don't like reading. This is a problem. But, when you can support others to start reading, it will be better. One of the books that can be recommended for new readers is computer aided analysis of electronic circuits algorithms and computational techniques. This book is not kind of difficult book to read. It can be read and understand by the new readers.

Computer-aided analysis of electronic circuits: Algorithms and computational techniques

This review presents the state of the art of the application of energy harvesting in commercial and residential buildings. Electromagnetic (optical and radio frequency), kinetic, thermal and airflow-based energy sources are identified as potential energy sources within buildings and the available energy is measured in a range of buildings. Suitable energy harvesters are discussed and the available and the potential harvested energy calculated. Calculations based on these measurements, and the technical specifications of state-of-the-art harvesters, show that typical harvested powers are: (1) indoor solar cell (active area of 9 cm2, volume of 2.88 cm3): ~300 µW from a light intensity of 1000 lx; (2) thermoelectric harvester (volume of 1.4 cm3): 6 mW from a thermal gradient of 25 °C; (3) periodic kinetic energy harvester (volume of 0.15 cm3): 2 µW from a vibration acceleration of 0.25 m s−2 at 45 Hz; (4) electromagnetic wave harvester (13 cm antenna length and conversion efficiency of 0.7): 1 µW with an RF source power of −25 dBm; and (5) airflow harvester (wind turbine blade of 6 cm diameter and generator efficiency of 0.41): 140 mW from an airflow of 8 m s−1. These results highlight the high potential of energy harvesting technology in buildings and the relative attractions of various harvester technologies. The harvested power could either be used to replace batteries or to prolong the life of rechargeable batteries for low-power (~1 mW) electronic devices.

http://iopscience.iop.org/article/10.1088/0957-0233/25/1/012002/pdf

Review of the application of energy harvesting in buildings

Since the beginning of the 20th century, researchers have been looking for an effective way to transfer power without wired connections, but the wireless power transfer technology started to attract extensive interest from the industry side only in 2007 when the first smartphone was released and a consumer electronics revolution was triggered. Currently, the modern technology of wireless power transfer already has a rich research and development history as well as outstanding advances in commercialization. This review is focused on the description of distinctive implementations of this technology inspired by the modern trends in electrodynamics. We compare the performances of the power transfer systems based on three kinds of resonators, i.e., metallic coil resonators, dielectric resonators, and cavity mode resonators. We argue that metamaterials and meta-atoms are powerful tools to improve the functionalities and to obtain novel properties of the systems. We review different approaches to enhance the fun...

Wireless power transfer inspired by the modern trends in electromagnetics

Condition monitoring is playing an increasingly important role within electrical power networks, where its use can help to reduce maintenance costs, improve supply reliability, and permit increased utilization of equipment capacity by providing a measure of actual operating conditions as an alternative to relying on more stringent “worst case scenario” assumptions. In this context, energy harvesting may have a role to play in that it offers the possibility of realizing autonomous, self-powering sensors that communicate their data wirelessly. In the vicinity of electrical transmission and distribution equipment, alternating magnetic fields at the power frequency offer a potential source of energy that does not require hard-wiring or batteries. There are many potentially useful locations for sensors where the level of magnetic flux density may be sufficient to provide enough power for a low-power wireless sensor node. This paper describes a free-standing inductive harvester for use in positions where there is an ambient magnetic field due to conductors that are remote and/or inaccessible. Using data from surveys of magnetic flux density levels at two substations, optimum core and coil designs for the harvester are obtained through theoretical analyses and experiments. A demonstrator is then constructed in which a wireless sensor becomes self-powering when immersed in a 50-Hz magnetic field. Laboratory results show that this system can deliver a useful average power of 300 $\mu{\rm W}$ when placed in a magnetic flux density of 18 $\mu T_{rms}$ .

/pdf/harvesting-energy-from-magnetic-fields-to-power-condition-2nv5jq29px.pdf

Harvesting Energy From Magnetic Fields to Power Condition Monitoring Sensors

MR. A. A. CAMPBELL SWINTON, in his letter on the above subject in NATURE of December 18, states that “it is hopeless to expect to be able to effect anything of this nature with the heat-engine, for with this we should scarcely reach the 2 per cent, efficiency nearly attained by vegetation.”

Power from the Sun

The environment of the city is surrounded by a lot of radio frequency (RF) energy that is broadcasted by diverse wireless systems. In order to enhance the value of the energy more than the channels to communicate, the ambient RF energy harvesting system was designed to harvest and recycle the energy for many applications such as battery chargers, sensor devices and portable devices. The main element of the ambient RF energy harvesting system is a rectenna that is the combination of an antenna and a rectifying circuit. Even though the ambient RF energy is widely broadcasted with many systems, the energy is extremely low. Therefore, the high performance of the antenna and the rectifying circuit has to be designed for supporting the small incident power; also the number of frequency channels of the rectenna can enhance the performance and support different harvesting locations. This paper proposes a dual-band rectifier for RF energy harvesting systems that was designed to operate at 2.1 GHz and 2.45 GHz. The first channel can provide the maximum efficiency of 24% with 1.9 V of the output voltage at 10 dBm of input power. On the other hand, a maximum efficiency of 18% and 1.7 V of the output voltage can be achieved by the second channel at 10 dBm of input power.

A dual-band rectifier for RF energy harvesting systems

The paper proposes three new low power CMOS dynamic latch comparators suitable for pipeline analog-to-digital converters. All three use the same differential comparing circuit that can be modeled as variable resistors to trigger the switching behavior of a cross coupled latch. However, their dynamic behaviors during the reset phase are different. The first one precharges the two outputs at HIGH state. The second one discharges the outputs at slightly above the threshold voltage. The third one uses charge sharing to attain approximately half the supply voltage at both outputs. Preliminary simulation shows that the charge sharing technique yields lowest power consumption of 90 /spl mu/W at 100 MHz. All three comparators have an offset voltage in the range of 30-150 mV.

Low power CMOS dynamic latch comparators

This paper presents a microcontroller controlled electromagnetic energy harvesting system suitable for harvesting energy from a single HV transmission line with current between 65A and 130A.The system comprises of magnetic power generator, standard voltage multiplier circuit, DC-DC boost converter and microcontroller. An adaptive algorithm has been applied to the microcontroller to adjust the duty cycle of the converter to achieve maximum output power. This enables the harvesting system to convert and store low voltage sinusoidal power induce from magnetic power generator into the battery for energizing various low power applications. The implemented system is able to operate with minimum sinusoidal induced voltage as low as 1V and can generate 58mW at 65 mA line current. Furthermore, simulation and experimental result as well as mathematical analysis are also included in this paper.

Adaptive electromagnetic energy harvesting circuit for wireless sensor application

In this article, we investigate the possibility of improving efficiency in wireless power transfer (WPT) using metamaterials. Our analysis differs from previous works on the metamaterial design for WPT in that we focus on the design of thin metamaterial slabs. Specifically, three types of metamaterials are considered: the double negative material, the μ-negative material, and the indefinite material (IM). Although in general, all three types of materials are capable of amplifying evanescent waves, when the thickness is small, the slab formed by IM offers the best performance in enhancing WPT efficiency, as the locations of the resonances introduced by the slab can be controlled more readily. Thus, we propose a tuning method by varying its material parameters to maximize the WPT efficiency. Full-wave simulations of a WPT system equipped with a thin IM slab show that the system efficiency can be enhanced by an order of magnitude, comparing with the conventional design. As an example, implementation of the thin IM slab, the capacitively loaded split-ring resonators are considered, and the enhancement of WPT efficiency shows a similar performance to the ideal homogeneous IM slab. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:867–875, 2014

Controlling the resonances of indefinite materials for maximizing efficiency in wireless power transfer

The investigation of applying metamaterials in the efficiency enhancement for wireless power transfer (WPT) systems is presented in this paper. Three types of metamaterials are considered: the double negative material (DNG), the isotropic μ-negative material (IMNG), and the anisotropic μ-negative material (AMNG). Through the transmission analysis, it is found that evanescent wave components are amplified by the metamaterial slabs, and the amplification is the highest for AMNG due to the presence of resonances. Numerical simulations show that a threefold enhancement in efficiency can be achieved when an AMNG slab is used in the WPT system.

Ekachai Leelarasmee

Papers

A dual-band rectifier for RF energy harvesting systems

Low power CMOS dynamic latch comparators

Adaptive electromagnetic energy harvesting circuit for wireless sensor application

Controlling the resonances of indefinite materials for maximizing efficiency in wireless power transfer

Improving the efficiency of wireless power transfer systems using metamaterials