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    Reliability Design Optimization of Casing Cap by Sample Test and FEA
    (2017-01-01)
    Buthgate, Siwawong
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    The parking brake cable in the brake system of a vehicle is an important part in the car. A new material needs to be studied; thus, this paper proposes the analysis and comparison of the results between real testing data and the simulation analysis using a Finite Element model of the part, new casing cap in parking brake cable. To validate and compare the results that can be used practically according to the qualifications and standards, the properties of the new product design, casing cap made from polyamide fiberglass composite, are investigated. By analyzing and comparing these results with the FEA design, the advantages of reduction of the weight and cost in the design process can be achieved. As show in the experimental and simulation results, the error less than 30% of the maximum pull load can be achieved.
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    Switching angle design for pulse width modulation AC voltage controller using genetic algorithm and distributed artificial neural network
    (2011-07-26)
    Jitta, Pattaraporn
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    This paper proposes a technique to design the switching angles in a PWM AC voltage controller using genetic algorithms (GA) and distributed artificial neural network (ANN). In the proposed technique, GA is used to evaluate the turn on and turn off angles of PWM pattern to reduce the low order harmonic content in PWM output voltage. The results from GA are then used to train the distributed ANN. The advantages gained from the proposed technique are the reduction of complexity of training process and the improvement of the ability of the ANN. In addition, the total harmonic distortion of voltage, which calculated from the low order harmonic content, is adopted in the proposed fitness function. Thus, the load value is not necessary to be known before stating the proposed technique. Simulation results show that the proposed technique is superior to the conventional fixed-duration pulse technique.
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    Fixed-structure mixed sensitivity/model reference control using evolutionary algorithms
    (2009-01-01)
    Srithongchai, Pitsanu
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    Olranthichachat, Piyapong
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    This paper proposes a mixed sensitivity/model reference control using evolutionary algorithms. The proposed technique can solve the problem of complicated and high order controller of conventional H∞optimal control. In addition, time domain specifications such as overshoot, undershoot, rise time can be incorporated in the design by formulating the appropriate fitness function of compact genetic algorithms. By the proposed approach, robustness and performance in terms of frequency domain and time domain specifications can be achieved simultaneously. Simulation results in a servo system verify the effectiveness of the proposed technique.
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    A new directional relay algorithm for the protection of transmission network systems using discrete wavelet transforms
    This paper proposes a novel directional relay algorithm to protect transmission network systems with an application of discrete wavelet transform (DWT). The fault signals are simulated using PSCAD/EMTDC. The coefficients of the positive sequence current obtained from each bus are compared in order to identify the direction of fault signals. The coefficient ratio between buses that the fault occurred is calculated so that the proper protective relay sequence can be selected. The result is shown that the algorithm is capable of performing the fault detection as well as arranging the protective relay sequence, with accurate results. ©2010 IEEE.
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    A novel robust load frequency controller for a two area interconnected power system using LMI and compact genetic algorithms
    (2009-12-01)
    Koisap, Chamnan
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    This paper proposes a new technique for designing a fixed-structure robust load frequency controller for a two area interconnected power system. The proposed technique uses Linear Matrix Inequality (LMI) method to form an initial solution, and then the global search algorithm, Compact Genetic Algorithm (cGA), is adopted for evaluating the final solution. By combining both techniques, LMI and cGA, a better solution in terms of robust performance can be achieved. Infinity norm from disturbances to states are formulated as the cost function in our optimization. The performance of the designed system is investigated in comparison with the conventional H infinity loop shaping controller, the robust controller designed by LMI method and the reduced order robust controller by Hankel norm model reduction method. As results indicated, stability margin of our proposed controller is better than that of the static controller designed by LMI method and the reduced order robust controller. In addition, order of the proposed controller is much lower than that of conventional robust loop shaping controller, making it easy to implement in practice. ©2009 IEEE.
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    PSO based decentralized robust power system stabilizer for a multi-machine power system
    (2012-06-12) ;
    Ussawapusitgul, Chanchai
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    Limcharoen, Worrakan
    This paper presents a new technique to design a robust Power System Stabilizer (PSS) in multi-machine power system. The Particle Swarm Optimization (PSO) is adopted to find the optimal parameters of the predefined structure decentralized controller. The main objectives of this research are to reduce the oscillation and to increase the overall robust performance of the system. The proposed technique adopts the stability margin (ε) as the index of robustness and performance of the controlled system. In addition, the optimal weight selection, which is a difficult process of the robust loop shaping design, can be achieved by the proposed technique. In this paper, the performance of the proposed controller is investigated in the standard IEEE four generators system in comparison with the classical robust loop shaping control. The results of rotor speed deviation of generators by the proposed PSS and the conventional PSS verify the effectiveness of the proposed algorithm.
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    Robust 2DOF fuzzy gain scheduling control for DC servo speed controller
    (2016-11-01)
    Chitsanga, Natchanon
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    This paper proposes a new design method called “robust 2DOF fuzzy gain scheduling control” for a DC servo speed control system. The proposed technique utilizes the basic concept of 2DOF robust loop shaping, whose time-domain specifications are combined during the controller design using a reference model. In addition, the local controllers are fixed- structure robust controllers whose structure can be specified as for a simple controller. A fuzzy approach is adopted in both system identification process and global control structure to accomplish an entirely robust system. Although the design of robust control in a fuzzy system is not easy, genetic algorithms (GAs) simplify the control design problem to design the fuzzy controller such that the average stability margin is minimized. Implementation of a DC servo speed control was adopted to investigate the effectiveness of the proposed controller. As seen from the results, the proposed controller has more robust performance and can be adopted in applications with a wide operating range. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
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    Enhancing the performance of fixed-structure robust loop shaping control using genetic algorithm approach
    (2011-07-26)
    Olranthichachat, Piyapong
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    This paper is proposed an algorithm, Genetic Algorithm (GA) based fixed-structure H<inf>∞</inf> loop shaping control, to the problem-solving of conventional H<inf>∞</inf> loop shaping, such as high-order and difficult to be usable in general. In this approach, a structure of controller is specified combine H<inf>∞</inf> loop shaping method is solved by GA algorithm. Additionally, in the proposed technique, the desired performance weighting function, which is defined by using GA. The performance and robustness of the proposed controller are investigated in a pneumatic servo system in comparison with that of the controller designed by conventional H <inf>∞</inf> loop shaping. Results of simulation demonstrate the advantages of simple structure and robustness against plant perturbations and disturbances of the proposed controller. Experiments are performed to verify the effectiveness of the proposed technique.
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    Robust voltage stabilization in an isolated wind-diesel power system using pso based-fixed structure H∞ loop shaping control
    (2009-07-30)
    Vachyirasricirikul, Sitthidet
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    It is well known that the power system controller designed by H∞ control is complicated, high order and impractical. In power system applications, practical structures such as proportional integral derivative (PID) etc., are widely used, because of their simple structure, less number of tuning parameters and low-order. However, tuning of controller parameters to achieve a good performance and robustness is based on designer's experiences. To overcome this problem, this paper proposes a fixed structure robust H∞ loop shaping control to design Static Var Compensator (SVC) and Automatic Voltage Regulator (AVR) for robust stabilization of voltage fluctuation in an isolated wind-diesel hybrid power system. The structure of the robust controller of SVC and AVR is specified by a PID controller. In the system modeling, a normalized coprime factorization is applied to represent possible unstructured uncertainties in the power system such as variation of system parameters, generating and loading conditions etc. Based on the H∞ loop shaping, the performance and robust stability conditions are formulated as the optimization problem. The particle swarm optimization is applied to solve for PID control parameters of SVC and AVR simultaneously. Simulation studies confirm the control effect and robustness of the proposed control. © 2009 The Institute of Electrical Engineers of Japan.
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    Automatic design of robust PSS for multimachine power system using PSO
    (2011-12-01)
    Ussawapusitgul, Chanchai
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    This paper presents a new technique to design a robust Power System Stabilizer(PSS) in multi-machine power system. The Particle Swarm Optimization(PSO) is adopted to find the optimal parameters of the predefined structure decentralized controller. The main objectives of this research are to reduce the oscillation and to increase the overall robust performance of the system. The proposed technique adopts the stability margin (ε) as the index of robustness and performance of the controlled system. In addition, the optimal weight selection, which is a difficult process of the robust loop shaping design, can be achieved by the proposed technique. In this paper, the performance of the proposed controller is investigated in the standard IEEE four generators system in comparison with the classical robust loop shaping control. The results of rotor speed deviation of generators by the proposed PSS and the conventional PSS verify the effectiveness of the proposed algorithm. © 2011 IEEE.