Current Issue : October - December Volume : 2016 Issue Number : 4 Articles : 5 Articles
This paper presents the design of a robust fixedââ?¬Âorder HâË?ž controller to damp out the interââ?¬Âarea\noscillations and to enhance the stability of the power system. The proposed HâË?ž approach is based\non shaping the openââ?¬Âloop transfer function in the Nyquist diagram through minimizing the quadââ?¬Â\nratic error between the actual and the desired open loop transfer functions in the frequency doââ?¬Â\nmain under linear constraints that guarantee robustness and stability. The proposed approach is\nrobust with respect to multiââ?¬Âmodel uncertainty closedââ?¬Âloop sensitivity functions in the Nyquist\ndiagram through the constraints on their infinity norm. The HâË?ž constraints are linearized with the\nhelp of a desired openââ?¬Âloop transfer function. The controller is designed using the convex optimiââ?¬Â\nzation techniques in which the difference between the openââ?¬Âloop transfer function and the desired\none is minimized. The twoââ?¬Âarea fourââ?¬Âmachine test system is selected to evaluate the performance\nof the designed controller under different load conditions as well as different levels of wind peneââ?¬Â\ntrations....
In this paper, a smart home system based on ZigBee technology is designed. The system includes\nhome network, home server and mobile terminal. The program is highly scalable and cost-effective.\nThis paper developed the home server-side application based on MFC technology and the mobile\nterminal application. The mobile client can remotely control home devices and query the running\nstate, electric energy information and historical data of home devices. At the same time, the home\nserver-side application can store electric energy information and electricity consumption of home\ndevices. Combined with household distributed photovoltaic generation system, the system can be\napplied to home energy management system. Through running tests and application, the results\nshow that the system has realized basic functions of smart home and achieved the desired design\ngoals....
Present technology has been shifting towards miniaturization of devices for energy production for\nportable electronics. Micro-combustors, when incorporated into a micro-power generation system,\ncreate the energy desired in the form of hot gases to power such technology. This creates the need\nfor a design optimization of the micro-combustor in terms of geometry, fuel choice, and material\nselection. A total of five micro-combustor geometries, three fuels, and three materials were computationally\nsimulated in different configurations in order to determine the optimal micro-combustor\ndesign for highest efficiency. Inlet velocity, equivalence ratio, and wall heat transfer coefficient\nwere varied in order to test a comprehensive range of micro-combustor parameters. All simulations\ncompleted for the optimization study used ANSYS Fluent v16.1 and post-processing of\nthe data was done in CFD Post v16.1. It was found that for lean, premixed fuel-air mixtures ( =\n0.6 - 0.9) ethane (C2H6) provided the highest flame temperatures when ignited within the microcombustor\ngeometries. An aluminum oxide converging micro-combustor burning ethane and air\nat an equivalence ratio of 0.9, an inlet velocity of 0.5 m/s, and heat transfer coefficient of 5 W/m2-K\nwas found to produce the highest combustor efficiency, making it the optimal choice for a microcombustor\ndesign. It is proposed that this geometry be experimentally and computationally investigated\nfurther in order to determine if additional optimization can be achieved...
The environmental and energy problems that have arisen in Turkey because of the dramatically\nincrease in energy consumption require the implementation of energy efficiency and microgeneration\nmeasures in the building sector which is the main sector of primary energy consumption.\nSince Turkey is highly dependent on exported energy resources, the basic energy policy approach\nis based on providing the supply security. In this regard, supporting for in situ energy production,\nencouraging the use of renewable energy sources and the systems such as microgeneration systems\nin order to meet the energy requirements of buildings would be considered as a key measure\nfor resolving the energy related challenges of Turkey and dealing with the sustainability issues.\nTurkey�s geographical location has several advantages for extensive use of most of the renewable\nenergy sources such as especially solar energy. However, this huge solar energy potential is not\nbeing used sufficiently in residential building sector which is responsible for the great energy\nconsumption of Turkey. Therefore, this paper aims to introduce a study which investigates, on a\nlife cycle basis, the environmental and the economic sustainability of solar Photovoltaic (PV) microgenerators\nto promote the implementation of this system as an option for the renovation of existing\nresidential buildings in Turkey. In this study, main parameters which were related to the\ndistribution of modules to be installed in flat roofs and facades and the evaluation of the PV systems\nwere taken into account. The effect of these parameters on energy generation of PV systems\nwas analyzed in a case study considering different climate zones of Turkey; and the decrease in\nthe existing energy consumption of the reference building was calculated....
Recently, Vernier permanent magnet (VPM) machines, one special case of magnetic\nflux-modulated (MFM) machines, benefiting from their compact, simple construction and low-speed/\nhigh-torque characteristics, have been receiving increasing interest. In this paper, the Vernier structure\nis integrated with an axial-flux PM machine to obtain the magnetic gear effect and produce an\nimproved torque density for direct-drive wind power generation application. Another advantage\nof the proposed machine is that the stator flux rotating speed can be relatively high when the shaft\nspeed is low. With this benefit, sensorless control strategy can be easily implemented in a wide speed\nrange. In this paper, an improved sliding mode observer (SMO) is proposed to estimate the rotor\nposition and the speed of the proposed machine. With the estimated shaft speeds, the maximum\npower point tracking (MPPT) control strategy is applied to maximize the wind power extraction.\nThe machine design and the sensorless MPPT control strategy are verified by finite element analysis\nand experimental verification....
Loading....