A fuzzy inference system (FIS) based sensor less maximum power point tracking (MPPT) algorithm has been proposed. The Fuzzy based controller has the ability to track the maximum power point (MPP) and the corresponding rotor speed of the wind generator by estimating wind speed with very little error compared to the conventional MPPT techniques. The algorithm developed is based on two series fuzzy networks, one for wind speed estimation and the other to determine the maximum power point and the corresponding rotor speed. The method demonstrates remarkable performance in estimating wind speed and to predict MPP accurately without undesired oscillations around maximum power point. The algorithm does not require any mechanical sensor for wind speed measurement. Nonlinear time domain simulations have been carried out to validate the effectiveness of the proposed controllers under different operating conditions. Simulation results confirm the effectiveness of the proposed MPPT controller in tracking the maximum power point under rapidly changing wind conditions.
One of the most promising applications of TCEs is a large-area transparent heater on the front window in automobiles, which allows convenient removal of fog on the indoor side of the windshield and frost on its outdoor surface. Considering that windshield fogging frequently occurs during driving, convenient way of fog removal on windshield can be directly related with safety of the people on board. Moreover, recent trend in the increasing demand of electrical automobiles is expected to generate a huge market for TCE technology, since electrical automobiles do not come with the air-blowing system, which is used in defogging and defrosting on windshield. Generally, it is understood that the critical technology in transparent heater is to achieve ultralow sheet resistance below 0.5 Ω □ −1 , while keeping the transmittance over 70% at the same time. Since the voltage of automobile batteries ranges only 12 to 16 V, the area of the most automobile windshields is over 1.0 m 2 and the gap between electrodes is over 700 mm, [3] achieving low-enough sheet resistance to be viable for real application is understood to be a difficult mission. As far as we have done searches in the related fields, no TCEs have been developed that can satisfy all those specifications at the same time. [2] Up until now, indium-tin oxide (ITO) has been most widely used in TCE industry. However, even with high optical transmittance reaching 90%, ITO has not been successful in application for automobile windshield due to relatively high sheet resistance (10 to 100 Ω □ −1 ). [4][5][6] Recent need for TCE technology introduced three different candidate materials including carbon-based materials, metal nanowires (NWs), and metal grids. Although carbon-based materials including carbon nanotubes (CNTs) [7][8][9][10][11] and graphene [12][13][14] has some advantage in flexibility, CNTs and graphenes have relatively high sheet resistance and low optical clarity compared with ITO. Among metal NWs, [15][16][17][18][19][20][21] silver nanowires (Ag NWs) have been improved greatly in recent years with their sheet resistance reaching around 30 Ω □ −1 , while keeping the transmittance up to 90%. However, a severe optical problem like "haze" Transparent heaters can be fabricated with a wide variety of materials including indium-tin oxide, carbon nano tubes, graphenes, metal nanowires, metal grids, and hybrid-type electrodes. However these materials have been applied to small area heaters below 0.01 m 2 because of the limit of electrical and optical properties. High-performance transparent electrodes for large-area purpose (over 1.0 m 2 ) have never been developed with any practical applicability in spite of their utility for removing fog or iced water on automobile windshield, which can be critical for safety and convenience of the drivers. Achieving ultralow resistance with high transparence is the major technical barrier in windshield heaters due to the intrinsic long distance between electrodes and low battery voltage in automobiles. In this study, a high per...
We indicated high performance and stability transparent heaters based on AlOx covered Ag nanowires. We obtained an AlOx covered Ag nanowire thin film which has a 47 ohm/sq of sheet resistance and 88.1% (substrate included) of transmittance at 600 nm on a flexible substrate. We demonstrate that the thin AlOx layer leads to increased contact area at the junction of Ag nanowires, which contributes to lower sheet resistance and improved adhesion of Ag nanowires. Furthermore, high stability and flexibility of Ag nanowire have been achieved by the AlOx layer. Finally, we fabricated a flexible transparent heater with AlOx covered Ag nanowire, and obtained a temperature of 81 °C within 40 sec at the driven voltage of 7 V with fast response and uniform temperature distribution. Therefore, the AlOx covered Ag nanowire film is a promising candidate for the application of the flexible transparent heaters.
ERW pipes formed with the roll forming process show a yield stress distribution along the circumferential direction and their quality is strongly influenced by the magnitude and by the distributions of the yield stress. In addition to that, strips are subjected to cyclic loading during roll forming process.\ud Since ERW pipes are firstly roll formed, welded and then sized, in order to develop an enhanced predicting method for the calculation of the ERW pipe yield stress, the same process flow has been also applied to authors’ numerical simulations.\ud The Yoshida-Uemori kinematic hardening model has been applied considering several subdivision of the strain range, and different parameters, aiming to find the best correlation between the estimated Bauschinger effect and the one measured in the relevant cyclic loading experiment.\ud The comparisons between estimated and experimentally-measured values of the thickness distribution, and of the locally-measured yield stress, prove both reliability and accuracy of the adopted process chain analysis.\ud The growth of the sizing effect ratio has shown to cause the increase of the yield stress, which becomes more uniform along the circumferential direction
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