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ABSTRACT: A toroidal field coil is composed of several individual toroidal coils (ITCs) which are connected in a series and distributed in a toroidal and symmetrical form. Cross section of ITCs is rectangular or negligible. This paper presents analytical equations of mutual inductance of two ITCs applicable to tokamak reactors using the filament method. These equations are based on those formulated by Neumann. The numerical analysis of the integrations resulting from these equations is solved using the extended three-point Gaussian algorithm. The finite element method (FEM) is employed to verify the mutual inductance equations of ITCs. The results obtained using FEM, when dimensional parameters of ITCs are changed, confirm the analytical and empirical results showing an error of less than 0.2043% in the worst case. This indicates the reliability of the presented equations. This paper also employs FEM to obtain depth of penetration of electromagnetic waves in high-conductivity conductors (HCCs). The results show that the ratio of real depth of penetration, obtained by FEM, to ideal depth of penetration in HCCs is independent of frequency. This ratio shows that the magnitude of traveling plane waves in HCC decreases with e <sup>-1.7916</sup> rather than e <sup>-1</sup>.
IEEE Transactions on Plasma Science 01/2011; · 1.17 Impact Factor
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ABSTRACT: A toroidal field coil (TFC) is composed of several individual toroidal coils (ITCs), which are connected in series and distributed in the toroidal and symmetrical forms. This paper presents the analytical equations of mutual inductance and electromagnetic torque of the TFC that are applicable to Tokamak reactors. The analytical equations of translational forces, which are imposed on the ITCs of the TFC, are also discussed in this paper. These equations are based on those formulated by Neumann. The numerical analysis of the integrations resulting from these equations is solved using the extended three-point Gaussian algorithm. The results obtained from the numerical simulation agree with the empirical results and the virtual work theorem, which indicates the reliability of the presented equations. The behavior of the mutual inductance of the coil shows that the maximum stored energy is obtained when the electromagnetic torque is zero and vice versa.
IEEE Transactions on Plasma Science 08/2010; · 1.17 Impact Factor
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ABSTRACT: In this paper, equations for the calculation of the self- and mutual inductances of the modular toroidal coil (MTC) applicable to Tokamak reactors are presented. The MTC is composed of several solenoidal coils (SCs) connected in series and distributed in the toroidal and symmetrical forms. These equations are based on Biot-Savart's and Neumann's equations, respectively. The numerical analysis of the integrations resulting from these equations is solved using the extended three-point Gaussian algorithm. Comparing the results obtained from the numerical simulation with the experimental and the empirical results confirms the presented equations. Furthermore, the comparison of the behavior of these inductances, when the geometrical parameters of the MTC are changed, with the experimental results shows an error of less than 0.5%. The behavior of the inductance of the coil indicates that the optimum structure of this coil, with the stored magnetic energy as the optimization function, is obtained when the SCs are located on the toroidal planes.
IEEE Transactions on Plasma Science 03/2010; · 1.17 Impact Factor
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ABSTRACT: The subsynchronous resonance (SSR) phenomenon may occur when a steam turbine-generator is connected to a long transmission line with series compensation. In this paper, to mitigate SSR, two control methodologies for turn-off angle control of the gate-controlled series capacitor (GCSC) are presented. The first methodology is an open-loop control that uses the line current frequency oscillations to generate proper turn-ff angle for the GCSC. The second one is a closed loop control that is based on the Takagi-Sugeno (TS) fuzzy logic controller. The study system was modified from the IEEE first benchmark model by changing a part of the fixed series capacitor to the GCSC. The MATLABreg program was used to verify the effectiveness of each control methodology. Three different GCSC ratings were analyzed. It is shown that using an open-loop control methodology, in some GCSC ratings, the SSR can be properly damped. It is also shown that using TS fuzzy control methodology, not only SSR but also electromechanical power oscillation can be effectively damped.
Compatibility and Power Electronics, 2009. CPE '09.; 06/2009
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ABSTRACT: Nowadays, high frequency waves have a so vital role in the industry. Cooking, pasteurization, defrosting, wood drying, etc. are some of the high frequency industrial applications. In this paper, an 800 W, 13.56 MHz radiofrequency heater has been designed, simulated and implemented. Variable loading is one of the major RF heaters problems. Usually, heaters have an optimum load in which they have their highest efficiency and the efficiency will dramatically decreased in heavier or lighter loading. Here, a type pi impedance matching system is used due to overcome this problem. Simulation results in Orcad software in two situations with and without impedance matching have been compared with laboratory results. These show that impedance matching system has greatly improved the amplifier's efficiency.
Power Engineering, Energy and Electrical Drives, 2009. POWERENG '09. International Conference on; 04/2009
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ABSTRACT: The subsynchronous resonance (SSR) is a potential problem in power systems having a steam turbine-generator connected to a series compensated transmission line. Flexible ac transmission systems (FACTS) controllers are widely applied to mitigate SSR. In this paper, two control ways for SSR damping for the gate-controlled series capacitor (GCSC) are presented. The first method is constant power control based on proportional (P) controller and the other one is based on Takagi-Sugeno (TS)-type fuzzy logic controller. The First IEEE Benchmark Model for the analysis of the SSR phenomenon is adopted. The actual possibility of controlling SSR was verified by MATLAB program. Three different GCSC ratings are evaluated. It will be shown that although the GCSC with the designed constant power control based on the P controller in the all considered GCSC ratings can damp SSR, it can not prepare a good dynamic response for the system. A comparative study between proportional and TS fuzzy controller is carried out showing that the performance of TS fuzzy controlled GCSC is better than that of P controlled GCSC, and SSR as well as electromechanical power oscillation can be properly damped by this method.
Power Engineering, Energy and Electrical Drives, 2009. POWERENG '09. International Conference on; 04/2009
