Electric Mechinces & Drive
M. Moazen; R. Kazemzadeh; M. R. Azizian
Abstract
Brushless doubly fed reluctance generator (BDFRG) has been recently suggested as a wind generator. Different control methods are presented in literature for the BDFRG, but there is a gap on control under unbalanced grid voltage condition (UGVC). This paper presents a predictive direct power control (PDPC) ...
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Brushless doubly fed reluctance generator (BDFRG) has been recently suggested as a wind generator. Different control methods are presented in literature for the BDFRG, but there is a gap on control under unbalanced grid voltage condition (UGVC). This paper presents a predictive direct power control (PDPC) method for the BDFRG under UGVC. The proposed PDPC method is based on power compensation strategy, and aims to balance the BDFRG current (strategy I), and to remove the electrical torque pulsation (strategy II). The control objectives are defined using the BDFRG positive sequence (PS) and negative sequence (NS) equations. Then, the active power and reactive power variations are predicted to compute the required voltage for the BDFRG control winding. Finally, the BDFRG is controlled by applying the calculated voltage to the control winding. Simulink toolbox of MATLAB software is used to simulate the system model. Both the proposed PDPC method (with strategies I & II) and the original PDPC method (without a compensation strategy) are applied to control of the BDFRG under UGVC, and the results are compared. The results show the good performance of the proposed PDPC method.
Power System Operation
R. Kazemzadeh; M. Moazen
Abstract
Many different methods have been presented to solve unit commitment (UC) problem in literature with different advantages and disadvantages. The need for multiple runs, huge computational burden and time, and poor convergence are some of the disadvantages, where are especially considerable in large scale ...
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Many different methods have been presented to solve unit commitment (UC) problem in literature with different advantages and disadvantages. The need for multiple runs, huge computational burden and time, and poor convergence are some of the disadvantages, where are especially considerable in large scale systems. In this paper, a new analytical and non-iterative method is presented to solve UC problem. In the proposed method, improved pre-prepared power demand (IPPD) table is used to solve UC problem, and then analytical “λ-logic” algorithm is used to solve economic dispatch (ED) sub-problem. The analytical and non-iterative nature of the mentioned methods results in simplification of the UC problem solution. Obtaining minimum cost in very small time with only one run is the major advantage of the proposed method. The proposed method has been tested on 10 unit and 40-100 unit systems with consideration of different constraints, such as: power generation limit of units, reserve constraints, minimum up and down times of generating units. Comparing the simulation results of the proposed method with other methods in literature shows that in large scale systems, the proposed method achieves minimum operational cost within minimum computational time.
