Current Issue : January - March Volume : 2016 Issue Number : 1 Articles : 5 Articles
Fundamental characteristics of on-chip micro solar cell (MSC) structures were investigated in this study. Several MSC structures\nusing different layers in three different CMOS processes were designed and fabricated. Effects of PN junction structure and\nprocess technology on solar cell performance were measured. Parameters for low-power and low-voltage implementation of power\nmanagement strategy and boost converter based circuits utilizing fractional voltage maximum power point tracking (FVMPPT)\nalgorithm were determined.The FVMPPT algorithm works based on the fraction between the maximum power point operation\nvoltage and the open circuit voltage of the solar cell structure. This ratio is typically between 0.72 and 0.78 for commercially available\npoly crystalline silicon solar cells that produce several watts of power under typical daylight illumination. Measurements showed\nthat the fractional voltage ratio is much higher and fairly constant between 0.82 and 0.85 for on-chip mono crystalline silicon micro\nsolar cell structures that produce microwatts of power.Mono crystalline silicon solar cell structures were observed to result in better\npower fill factor (PFF) that is higher than 74% indicating a higher energy harvesting efficiency....
Magnetocaloric effects of various materials are getting more and more interesting for the future, as they can significantly contribute\ntowards improving the efficiency of many energy intensive applications such as refrigeration, heating, and air conditioning.\nAccurate characterization of magnetocaloric effects, exhibited by various materials, is an important process for further studies and\ndevelopment of the suitable magnetocaloric heating and cooling solutions.The conventional test facilities have plenty of limitations,\nas they focus only on the thermodynamic side and use magnetic machines with moving bed of magneto caloric material or magnet.\nIn this work an entirely new approach for characterization of the magnetocaloric materials is presented, with the main focus on a\nflexible and efficient power electronic based excitation and a completely static test platform. It can generate a periodically varying\nmagnetic field using superposition of an ac and a dc magnetic field.The scale down prototype uses a customized single phase Hbridge\ninverter with essential protections and an electromagnet load as actuator. The preliminary simulation and experimental\nresults show good agreement and support the usage of the power electronic test platform for characterizing magnetocaloric\nmaterials....
Dams for water supply usually represent an untapped hydroelectric potential. It is a small energetic\npotential, in most situations, usually requiring a particular solution to be viable. The use of\npumps as power turbines often represents an alternative that enables the power generation in\nhydraulic structures already in operation, as is the case of dams in water supply systems. This potential\ncan be exploited in conjunction with the implementation of PV modules on the water surface,\ninstalled on floating structures, both operating in a hydro PV hybrid system. The floating\nstructure can also contribute to reducing the evaporation of water and providing a small increase\nin hydroelectric power available. This paper presents a pre-feasibility study for implementation of\na hydroelectric power plant and PV modules on floating structures in the reservoir formed by the\ndam of Val de Serra, in southern Brazil. The dam is operated to provide drinking water to about\n60% of the population of the city of Santa Maria, in the state of Rio Grande do Sul, in southern Brazil.\nThe pre-feasibility study conducted with Homer software, version Legacy, indicated that the\nhydroelectric plant with a capacity of 227 kW can operate together with 60 kW of PV modules. This\ncombination will result (in one of the configurations considered) in an initial cost of USD$ 1715.83\nper kW installed and a cost of energy of USD$ 0.059/kWh....
It is well-known that energy harvesting from wind can be used to power remote\nmonitoring systems. There are several studies that use wind energy in small-scale systems, mainly\nwith wind turbine vertical axis. However, there are very few studies with actual implementations of\nsmall wind turbines. This paper compares the performance of horizontal and vertical axis wind\nturbines for energy harvesting on wireless sensor network applications. The problem with the use of\nwind energy is that most of the time the wind speed is very low, especially at urban areas. Therefore,\nthis work includes a study on the wind speed distribution in an urban environment and proposes a\ncontroller to maximize the energy transfer to the storage systems. The generated power is evaluated\nby simulation and experimentally for different load and wind conditions. The results demonstrate the\nincrease in efficiency of wind generators that use maximum power transfer tracking, even at low\nwind speeds....
A power router has been recently developed for both AC and DC applications\nthat has the potential for smart-grid applications. This study focuses on three-phase\npower switching through the development of an experimental setup which consists of a\nthree-phase direct AC/AC matrix converter with a power router attached to its output.\nVarious experimental switching scenarios with the loads connected to different input sources\nwere investigated. The crescent introduction of decentralized power generators throughout\nthe power-grid obligates us to take measurements for a better distribution and management\nof the power. Power routers and matrix converters have great potential to succeed this goal\nwith the help of power electronics devices. In this paper, a novel experimental three-phase\npower switching was achieved and the advantages of this operation are presented, such as\non-demand and constant power supply at the desired loads....
Loading....