KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 19

Some of the metrics are blocked by your
consent settings
Optimal capacitances compensation for short-shunt self-excited induction generator under inductive load
(2009-12-01)
Phumiphak, P.
;
Chat-uthai, C.
This paper presents a technique for evaluating the optimal values of capacitances necessary to maintain the power quality of voltage regulation of the short-shunt self-excited induction generator (SEIG) feeding to the desired pu load under various lagging power factor conditions. The optimal values of shunt and series capacitances, and the optimal relation of ratio of air gap voltage to frequency with magnetizing reactance for the minimum voltage regulation of SEIG are evaluated by using the technique of genetic algorithm (GA) based on the equivalent circuit parameters of machine. Experimental results of 0.75 kW, short-shunt SEIG are performed to confirm the effectiveness of this proposed technique. The results are experimentally verified, which illustrate that the voltage regulations of SEIG under different inductive loads are within the limit of ± 0.06 pu.
Some of the metrics are blocked by your
consent settings
Fixed structure robust loop shaping controller for a buck-boost converter using evolutionary algorithm
(2009-09-25)
Kaitwanidvilai, S.
;
Jangwanitlert, A.
;
Ngarmroo, I.
;
Khanngern, W.
;
Karnprachar, S.
In this paper, we propose a new technique used to design a robust controller that is not as high-order and complicated as the ones designed by conventional <inf>∞</inf> loop shaping method. The proposed algorithm is called Genetic Algorithm (GA) based fixed-structure H <inf>∞</inf> loop shaping control. In the approach, GA is adopted to solve the H <inf>∞</inf> loop shaping design problem under a structure specified controller. The performance and robustness of the proposed controller are investigated in a buck-boost converter in comparison with the controllers designed by conventional H <inf>∞</inf> loop shaping and conventional ISE method. Results of simulations demonstrate the advantages of the proposed controller in terms of simple structure and robustness against plant perturbations and disturbances. Experiments are performed to verify the effectiveness of the proposed technique. © 2009 Springer Netherlands.
Some of the metrics are blocked by your
consent settings
Reliability optimization of topology communication network design using an improved ant colony optimization
(2009-09-01)
Watcharasitthiwat, Kanyapat
;
Wardkein, Paramote
Network design problem is a well-known NP-hard problem which involves the selection of a subset of possible links or a network topology in order to minimize the network cost subjected to the reliability constraint. To overcome the problem, this paper proposes a new efficiency algorithm based on the conventional ant colony optimization (ACO) to solve the communication network design when considering both economics and reliability. The proposed method is called improved ant colony optimizations (IACO) which introduces two addition techniques in order to improve the search process, i.e. neighborhood search and re-initialization process. To show its efficiency, IACO is applied to test with three different topology network systems and its results are compared with those obtained results from the conventional approaches, i.e. genetic algorithm (GA), tabu search algorithm (TSA) and ACO. Simulation results, obtained these test problems with various constraints, shown that the proposed approach is superior to the conventional algorithms both solution quality and computational time. © 2009 Elsevier Ltd. All rights reserved.
Some of the metrics are blocked by your
consent settings
Robust frequency control of wind-diesel hybrid power system using superconducting magnetic energy storage
(2009-04-23)
Ngamroo, Issarachai
In an isolated wind-diesel hybrid power system, the variable power consumptions as well as the intermittent wind power may cause a large fluctuation of system frequency. If the system frequency can not be controlled and kept in the acceptable range, the system may lose stability. To reduce system frequency fluctuation, a superconducting magnetic energy storage (SMES) which is able to supply and absorb active power quickly, can be applied. In addition, variation of system parameters, unpredictable power demands and fluctuating wind power etc., cause various uncertainties in the system. A SMES controller which is designed without considering such uncertainties may lose control effect. To enhance the robustness of SMES controller, this paper focuses on a new robust control design of SMES for frequency control in a wind-diesel system. The coprime factorization is used to represent the unstructured uncertainties in a system modeling. The structure of a SMES controller is the practical first-order lead-lag compensator. To tune the controller parameters, the optimization problem is formulated based on loop shaping technique. The genetic algorithm is applied to solve the problem and achieve the control parameters. Simulation results confirm the high robustness of the proposed SMES controller with small power capacity against various disturbances and system uncertainties in comparison with SMES in the previous research. © 2009 The Berkeley Electronic Press. All rights reserved.
Some of the metrics are blocked by your
consent settings
Inverse additive perturbation-based optimization of robust PSS in an interconnected power system with wind farms
(2008-12-01)
Cuk Supriyadi, A. N.
;
Ngamroo, I.
;
Kunakorn, A.
;
Dechanupaprittha, S.
;
Watanabe, M.
This paper proposes a design of robust power system stabilizer (RPSS) based on inverse additive perturbation optimization in an interconnected power system with wind farms. In the design, system uncertainties are represented by the inverse additive model. The robust stability condition is used to form the optimization problem of PSS parameters. The structure of PSS is a conventional second-order lead-lag controller. The genetic algorithm is applied to solve the problem and achieve the PSS parameters. Simulation studies in the two-area four-machine system with wind farms confirm that the damping effect and robustness of the proposed PSS are superior to those of the compared PSS. © 2008 SICE.
Some of the metrics are blocked by your
consent settings
Hybrid algorithm for adaptive IIR notch filter
(2008-12-01)
Jorphochaudom, S.
;
Benjangkaprasert, C.
;
Sangaroon, O.
;
Janchitrapongvej, K.
In this paper presents the hybrid algorithm for adaptive IIR notch filter using the combination of genetic algorithm in parallel with variable step-size algorithm. This application is used for frequency estimation in background noise such as Gaussian noise or impulse noise. The objectives are enhancing the performance of adaptive IIR notch filter, for instance, fast convergence speed, low mean square error (MSE) and especially for noise robustness in high amplitude impulse noise situation. From the experiment results show that the proposed algorithm gives good performance, such as fast convergence speed, noise robustness, low MSE and can be used to eliminating 50 Hz power line interference, which induce to disturb the signal of electrocardiogram (ECG) of patient while the physician is recording it.
Some of the metrics are blocked by your
consent settings
Towards adapting XCS for imbalance problems
(2008-12-01)
Nguyen, Thach Huy
;
Foitong, Sombut
;
Srinil, Phaitoon
;
Pinngern, Ouen
The class imbalance problem has been recognized as a crucial problem in machine learning and data mining. Learning systems tend to be biased towards the majority class and thus have poor performance in classifying the minority class instances. This paper analyzes the imbalance problem in accuracy-based learning classifier system XCS. XCS has shown excellent performance on some data mining tasks, but as other classifiers, it also performs poorly on imbalance data problems. We analyze XCS's behavior on various imbalance levels and propose an appropriate parameter tuning to improve performance of the system. Particularly, XCS is adapted to eliminate over-general classifiers and protect accurate classifiers of minority class. Experimental results in Boolean function problems show that, with proposal adaptations, XCS is robust to class imbalance. © 2008 Springer Berlin Heidelberg.
Some of the metrics are blocked by your
consent settings
Design of robust SVC for voltage control in an isolated wind-diesel hybrid power system
(2008-10-06)
Vachirasricirikul, S.
;
Ngamroo, I.
;
Kaitwanidvilai, S.
This paper focuses on a new robust control design of Static Var Compensator (SVC) for voltage control in an isolated wind-diesel hybrid power system. The proposed method is based on the H<inf>∞</inf> loop shaping technique and genetic algorithm (GA). The structure of the controller is a proportional integral (PI) controller with single input. In the design, system uncertainties are modeled by a normalized coprime factorization. The performance and robust stability conditions of the designed system satisfying the H<inf>∞</inf> loop shaping are formulated as the objective function in the optimization problem. The GA is applied to solve an optimization problem and to achieve control parameters. Simulation studies show the effectiveness and robustness of the proposed method. © 2008 IEEE.
Some of the metrics are blocked by your
consent settings
Robust pitch controller design in hybrid wind-diesel power generation system
(2008-09-23)
Cuk Supriyadi, A. N.
;
Ngamroo, I.
;
Kaitwanidvilai, S.
;
Kunakorn, A.
;
Hashiguchi, T.
In this paper, the robust control design of pitch controller for frequency control in a hybrid wind-diesel power generation system is proposed. The structure of the pitch controller is a 1<sup>st</sup>-order lead-lag compensator. To take system uncertainties into account, the coprime factorization is applied in system modeling. To obtain the controller parameters, the performance and stability conditions of H<inf>∞</inf> loop shaping technique are used to formulate the optimization problem. The genetic algorithm is employed to solve the problem. Simulation studies show the frequency control effect and robustness of the proposed controller against system uncertainties in comparison with a variable structure pitch control. ©2008 IEEE.
Some of the metrics are blocked by your
consent settings
Application of multiple tabu search algorithm to solve dynamic economic dispatch considering generator constraints
(2008-04-01)
Pothiya, Saravuth
;
Ngamroo, Issarachai
;
Kongprawechnon, Waree
This paper presents a new optimization technique based on a multiple tabu search algorithm (MTS) to solve the dynamic economic dispatch (ED) problem with generator constraints. In the constrained dynamic ED problem, the load demand and spinning reserve capacity as well as some practical operation constraints of generators, such as ramp rate limits and prohibited operating zone are taken into consideration. The MTS algorithm introduces additional mechanisms such as initialization, adaptive searches, multiple searches, crossover and restarting process. To show its efficiency, the MTS algorithm is applied to solve constrained dynamic ED problems of power systems with 6 and 15 units. The results obtained from the MTS algorithm are compared to those achieved from the conventional approaches, such as simulated annealing (SA), genetic algorithm (GA), tabu search (TS) algorithm and particle swarm optimization (PSO). The experimental results show that the proposed MTS algorithm approaches is able to obtain higher quality solutions efficiently and with less computational time than the conventional approaches. © 2007 Elsevier Ltd. All rights reserved.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results