Wyniki wyszukiwania - BazTech

1

Coordinated design of PSS and TCSC based on Fuzzy controller using global signals

Ghasemi A., Shayeghi H.

Journal of Power Technologies

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2018

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Vol. 98, nr 1

106--120

EN

This paper presents a modified chaotic gravitational search algorithm (CGSA) as a novel heuristic algorithm for coordinate design of fuzzy logic controller-based thyristor controlled series capacitor (FLC-TCSC) and power system stabilizers (PSSs) in multi-machine power system. The coordinate design of PSS and FLC-TCSC damping controllers is converted to a single optimization problem with the time-domain objective function which is solved by the proposed CGSA algorithm which has strong ability for finding the most optimistic results. By minimizing the employed fitness function in which oscillatory characteristics between areas are included, the interactions among the FLC-TCSC controller and PSS under transient conditions in the multi-machine power system are enhanced. The generator speed and the electrical power are chosen as global input signals. The system performance is assessed through the time multiplied absolute value of the error (ITAE), Eigenvalues and figure of demerit (FD) analysis performance indices. The robustness is tested by considering several operating conditions to establish the superior performance with the proposed controller over the other stabilizers.

2

Metaheuristic Search Algorithms in Solving the n-Similarity Problem

Mirhosseini M., Nezamabadi-pour H.

Fundamenta Informaticae

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2017

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Vol. 152, nr 2

145--166

EN

The - similarity problem, finding a group of objects which have the most similarity to each other, has become an important issue in information retrieval and data mining. The theory of this concept is mathematically proven, but it practically has high time complexity. Binary Genetic Algorithm (BGA) has been applied to improve solutions quality of this problem, but a more efficient algorithm is required. Therefore, we aim to study and compare the performance of four metaheuristic algorithms called Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), Imperialist Competitive Algorithm (ICA) and Fuzzy Imperialist Competitive Algorithm (FICA) to tackle this problem. The experiments are conducted on two applications; the former is on four UCI datasets as a general application and the latter is on the text resemblance application to detect multiple similar text documents from Reuters datasets as a case study. The results of experiments give a ranking of the algorithms in solving the -similarity problem in both applications based on the exploration and exploitation abilities, that the FICA achieves the first rank in both applications as well as based on the both criteria.

3

Gravitational search optimization approach to improve fuzzy logic speed controller for induction motor drive

Ali J. A., Hannan M. A., Mohamed A.

Przegląd Elektrotechniczny

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2016

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R. 92, nr 8

200--205

EN

Fuzzy logic controller (FLC) is very useful for controlling speed and torque variables in the three-phase induction motor (TIM) operation. However, the conventional FLC has the exhaustive traditional trial and error procedure in obtaining membership functions (MFs). This paper presents an adaptive FLC design technique for TIM using a gravitational search algorithm (GSA) optimization technique. This technique provides the numerical values to limit the error and change in error of the MFs based on the evaluation results of the objective function formulated by the GSA. The root mean square error (RMSE) of the speed response is used as a fitness function. An optimal GSA- based FLC (GSAF) fitness function is also employed to tune and minimize the RMSE for improving the performance of the TIM in terms of changes speed and torque. Space vector pulse width modulation (SVPWM) technique is utilized to generate signals via voltage/frequency control strategy for variable frequency inverter. Results obtained from the GSAF are compared with those obtained through particle swarm optimization (PSO) to validate the developed controller. The robustness of the GSAF is better than that of the PSO controller in all tested cases in terms of damping capability and transient response under different load and speed.

PL

W artykule zaprezentowano adaptacyjny sterownik typu fuzzy logic przeznaczony do trójfazowego silnika indukcyjnego wykorzystujący algorytm optymalizacyjny badania grawitacyjnego. Jako funkcję fitness użyto błąd rms odpowiedzi prędkości. Do zasilania silnika wykorzystano metodę modulacji szerokości impulsu.

4

A Clustering Based Archive Multi Objective Gravitational Search Algorithm

Abbasian M. A., Nezamabadi-pour H., Amoozegar M.

Fundamenta Informaticae

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2015

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Vol. 138, nr 4

387--409

EN

Gravitational search algorithm(GSA) is a recent createdmetaheuristic optimization algorithm with good results in function optimization as well as real world optimization problems. Many real world problems involve multiple (often conflicting) objectives, which should be optimized simultaneously. Therefore, the aim of this paper is to propose a multi-objective version of GSA, namely clustering based archive multi-objective GSA (CA-MOGSA). Proposed method is created based on the Pareto principles. Selected non-dominated solutions are stored in an external archive. To control the size of archive, the solutions with less crowding distance are removed. These strategies guarantee the elitism and diversity as two important features of multi-objective algorithms. The archive is clustered and a cluster is randomly selected for each agent to apply the gravitational force to attract it. The selection of the proper cluster is based on the distance between clusters representatives and population member (the agent). Therefore, suitable trade-off between exploration and exploitation is provided. The experimental results on eight standard benchmark functions reveal that CA-MOGSA is a well-organized multi-objective version of GSA. It is comparable with the state-ofthe- art algorithms including non-dominated sorting genetic algorithm-II (NSGA-II), strength Pareto evolutionary algorithm (SPEA2) and better than multi-objective GSA (MOGSA), time-variant particle swarm optimization (TV-PSO), and non-dominated sorting GSA (NSGSA).

5

Optimal Sizing and Placement of Distributed Generation in Distribution System Considering Losses and THDv using Gravitational Search Algorithm

Abdul Kadir A., Mohamed A., Shareef H., Che Wanik M., Ibrahim A.A.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 4

132-136

EN

This paper presents a new method for determining optimal sizing and suitable placement for distributed generation (DG) in distribution system. A multi-objective function is created to minimise the total losses and average voltage total harmonic distortion (THDv) of the distribution system. The proposed method utilizes gravitational search algorithm (GSA )in the optimization process and its performance is compared with other optimization techniques such as particle swarm optimisation (PSO) and evolutionary programming (EP). The results show that the GSA performs better than PSO and EP by giving the best fitness value and convergence rate.

PL

W artykule opisano metodę optymalizacji rozmieszczenia i mocy generatorów energii w systemie rozproszonym. Opracowana została funkcja wielokryterialna, służąca do minimalizacji całkowitych strat i wskaźnik THD napięcia. Optymalizacja dokonywana jest z wykorzystaniem algorytmu GSA. Jego działanie zostało porównane z działaniem innych metod, jak PSO i EP. Przedstawiono wyniki porównania.

6

Automatic Generation Control of the Two Area Non-reheat Thermal Power System using Gravitational Search Algorithm

Duman S., Yorukeren N.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 10a

254-259

EN

In this study, determination of the optimal proportional-integral-derivate (PID) parameters with Gravitational search algorithm (GSA) for automatic generation control (AGC) of the two area non-reheat thermal power system is proposed. GSA is applied to search for the optimal PID controller parameters to minimize various performance indexes. The designed PID controller with the proposed approach is simulated under variety of operating conditions. Simulation results are shown that dynamic performance of the two area non-reheat thermal power system is improved by the designed PID controller with the proposed approach.

PL

W artykule zaproponowano określenie optymalnej wartości PID w cieplnym systemie wytwarzania energii. Do tego celu użyto algorytmu grawitacyjnego GSA. Opracowany sterownik został zbadany metodami symulacyjnymi. (Automatyczne sterowanie cieplnym system wytwarzania energii z wykorzystaniem algorytmu grawitacyjnego GSA)