توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Experimental Measurement of Pressure Coefficients arounnd Various Opening of Typical Wind Catchers
نویسنده(ها): ، ، ،
اطلاعات انتشار: سال
تعداد صفحات: ۸
Wind catcher or what is called Baud – Girs in Persian language was a main component of old buildings in central region of Iran. Its function was to capture wind from external air stream and induce it into the building in order to provide natural ventilation and passive and passive cooling . it is normally a tall any direction and guiding it into the building to provide thermal comfort for occupants during the summer time. In the cold seasons, the openings were closed to isolate thee Baud–Gir and occupant regions. In this article, a 1:100 scale model of Larih’s house Baud–Gir with a cross section is employed in a laboratory wind tunnel and pressure coefficients were measured around all opening for various values of approaching air velocity and air incident angel. The experiments are also conducted when the Baud–Gir with adjoining courtyard is placed in the wake of upstream objects, resembling neighboring building . Two types of upstream objects are selected with different heights. For an isolated Baud–Gir model and for zero incident angel, it is shown that the pressure coefficients in the front or projected surface are positive and become negative downward. The same behavior is observed for other velocities. However , the pressure coefficient distributions for the back are all negative and almost uniform, indicating a large low pressure region around this face. The effect of increasing the air incident angle is to lower the pressure coefficients along the front face. For the zero incident angle, the shading effects of upstream building was to both reducing and flattening of the pressure distribution in the projects surface of the model. For thee taller upstream object, the pressure coefficients in the projected surface become uniform and negative , indicating that the model Baud–Gir is total under the wake of the upstream building and therefore in capable its duty properly.<\div>

۲An Improved Vector controlled csi –fed induction motor drive using an active filter
نویسنده(ها): ، ،
اطلاعات انتشار: اولین کنفرانس بین المللی الکترونیک قدرت و سیستم های درایو، سال
تعداد صفحات: ۷
Current source inverter (CSII)–fed induction motor drives are commonly used foor high power applications without necessity to fast dyynamic response. Although these kind of drives are more eeconomic in high power ratings, they have some inherentt disadvantages, that limit their applications. In this pape r, in addition to presenting vector control system of CSSI–fed induction motor drives, a novel method has beeen presented to remove some disadvantages and improve their performance. In this method, a voltage souurce inverter has been used as a shunt active filter. Results show the effects of this method on the overall drive set an d especially load currents. The method leads to improve toorque and speed control in wide range of speed variationss that have been problematic in traditional CSI–fed motor<\div>
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