عنوان مقاله
مطالعه مقایسه ای مبدل های جریان مستقیم/ متناوب در کوره قوسی جریان مستقیم با توان بالا
فهرست مطالب
چکیده
فهرست
ساختار و کنترل منابع کوره قوسی مستقیم
مقایسه بین منابعDC با کنترل توان ثابت و منابع تریستور
نتیجه گیری
بخشی از مقاله
B. مبدلAC/DC توان واکنشی ثابت
به منظور کاهش تغییرات توان واکنشی ، در بخشهای پیشنهاد شده است از یکسوکننده های تریستور با دیودهای آزاد در حال کار با استراتژی کنترل توان واکنشی ثابت استفاده شود. شکل 1(b) توپولوژی این منبع با استفاده از دیودهای آزاد متصل به نقطه بی اثر سیم پیچ های ثانویه را نشان می دهد. به منظور کنترل هر یکسوکننده، دو زاویه ap (سلول کاتد معمولی) و an (سلول آند معمولی) به کار گرفته شده است. هدف از زوایای مذکور کنترل مستقل توان موثر و واکنشی در طیف کاری وسیع می باشد.
کلمات کلیدی:
A Comparative Study of AC/DC Converters for High-Power DC Arc Furnace Philippe Ladoux, Gianluca Postiglione, Henri Foch, and Jacques Nuns Abstract—Today, dc arc furnaces are supplied by thyristor rectifiers. Because of the phase control strategy on the rectifiers, the arc voltage swings induce large reactive power variations on the power network and a static var compensator (SVC) or a static synchronous compensator (STATCOM) is always added to avoid flicker effect. In this paper, the authors present a new control strategy which suppress the flicker effect and increases the furnace productivity. To supply the dc arc furnace, the ac/dc converter is based on diode rectifiers and choppers with a constant power control strategy. Consequently, the ac/dc converter can operate without a STATCOM or an SVC. To evaluate the gain in flicker and furnace productivity, simulations are done with Matlab software. These simulations take into account arc voltage measurements on a 100-MW dc arc furnace and allow for comparison of the different solutions. Index Terms—DC arc furnace, dc power supply, industrial applications, power quality, reduction of flicker effect, simulation. I. INTRODUCTION ELECTRICAL arc furnaces are used in the steel industry to melt scraps (35% of the world steel production). They are one of the most powerful electrical loads and they can be supplied with alternating current or direct current. The dc solution is less polluting for the power networks, regarding flicker, power factor, and harmonics [1]. Classically, for a 100-MW dc arc furnace, supplied by thyristor rectifiers with a pulse number of 24, the low-rank harmonic currents at the point of common coupling (PCC) are lower than 1% of the fundamental current [2]. The flicker effect, induced by the low-frequency modulation (between 0.5–20 Hz) of the voltage at the PCC, is the major disturbance. A static var compensator (SVC) or a static synchronous compensator (STATCOM) must be added to the thyristor recti- fiers to compensate the reactive power fluctuation. The dimensioning of the SVC or STATCOM depends on the level of these fluctuations. Compared to a STATCOM, an SVC structure with thyristor-controlled reactors (TCRs ) and shunt passive filters is a low-cost solution at this level of power. The STATCOM solution, based on voltage-source inverters, has a reduced volume (no passive filter) and a better response time with respect to the reactive power fluctuations. The aim of this paper is to show how it is possible to reduce the flicker effect on the power network Manuscript received November 28, 2003; revised January 30, 2004. Abstract published on the Internet March 14, 2005. P. Ladoux, G. Postiglione, and H. Foch are with the Laboratoire d’Electrotechnique et d’Electronique Industrielle, Unité Mixte de Recherche INPT-ENSEEIHT/CNRS, BP 7122, 31071 Toulouse Cedex 7, France (e-mail: philippe.ladoux@leei.enseeiht.fr). J. Nuns is with the Direction des Etudes et Recherches-Site des Renardières, Electricité de France, 77818 Moret sur Loing, France. Digital Object Identifier 10.1109/TIE.2005.843941 and to avoid the use of an SVC or a STATCOM. Compared to a STATCOM solution, which compensates the reactive power and has no effect on the furnace working, the new constant power control strategy, proposed by the authors, and applied to a diode rectifiers/choppers structure allows increasing the electrical energy transferred to the furnace. This is a major advantage for the steelmaker who can increase the furnace productivity
