• 대한전기학회논문지:전력기술부문A
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• 제48권6호
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• pp.671-677
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• 1999

In this paper, we have designed power system stabilizer (PSS) using object-oriented method. There are several types of power system stabilizer. A proportional-integral(PI) controller is very simple for practical implementation. Therefore it has been widely employed by the industry. The methods of obtaining the gains(Ki,Kp) of PI controller are root-locus method and sub-optimal regulator approach. But these methods are cannot be applicable to nonlinear system and faulted power system. So we proposed a new method which can be applied to nonlinear system by numerical analysis method. The method of dynamic system simulation by numerical method is very difficult and complex. We proposed flexible simultaion method for complex power system analysis using object-oriented programming(OOP) and applied to PI controller design.

• Journal of Power Electronics
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• 제19권4호
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• pp.835-845
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• 2019

This paper presents a robust-optimal control strategy to improve the output-voltage error-tracking and control capability of a DC-DC boost converter. The proposed strategy employs an optimized Fractional-order Proportional-Integral (FoPI) controller that serves to eliminate oscillations, overshoots, undershoots and steady-state fluctuations. In order to significantly improve the error convergence-rate during a transient response, the FoPI controller is augmented with a pre-stage nonlinear error-modulator. The modulator combines the variations in the error and error-derivative via the signed-distance method. Then it feeds the aggregated-signal to a smooth sigmoidal control surface constituting an optimized hyperbolic secant function. The error-derivative is evaluated by measuring the output-capacitor current in order to compensate the hysteresis effect rendered by the parasitic impedances. The resulting modulated-signal is fed to the FoPI controller. The fixed controller parameters are meta-heuristically selected via a Particle-Swarm-Optimization (PSO) algorithm. The proposed control scheme exhibits rapid transits with improved damping in its response which aids in efficiently rejecting external disturbances such as load-transients and input-fluctuations. The superior robustness and time-optimality of the proposed control strategy is validated via experimental results.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권1호
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• pp.18-25
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• 2000

In the two-mass servo system driving a load through a flexible shaft, a shaft torsional vibration is often generated. PI controller has been generally used is speed control of such system because of the simplicity of structure and related theory. This paper presents the inertia ratio of the PI servo control system which can be designed by using optimal pole assignment method is fixed. Therefore, it's difficult to obtain the desired control characteristics for different systems only by PI control algorithm. To solve this problems the two-mass speed control system with PID controller is designed by using pole assignment method and an optimum PID parameters are derived by evaluating ITAE(Integral of time multiplied by the absolute error) performance index. But this design method has some problems due to a trade-off between the fast command following property and the attenuation of disturbances and vibrations. In this paper, 2-DOF PID control method which satisfies the command following property, the reduction of overshoot and the property of disturbance rejection at the same time is proposed. This is a practical speed controller using the desired value filter and the feedforward gain. From several simulations, it's clarified that the proposed 2-DOF PID controller is useful for the two-mass system, in comparison with the conventional PID controller.

• 전자공학회논문지SC
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• 제41권5호
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• pp.37-42
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• 2004

다변수 제어시스템의 최적 PI동조에 관한 연구는 난해하기 때문에 일반적인 방법으로 접근하기 힘들다. 본 논문에서는 다변수 시스템을 2-입력, 2-출력의 2차시스템을 고려하여 PI제어요소가 포함된 폐루프 상태방정식과 LQR의 폐루프 상태방정식의 관계를 유도하는 루프형성절차를 통해 주파수 영역 설계사양과 만족할 수 있도록 가격함수의 가중치 요소 Q와 R을 선정함으로써 성능 및 안정도-강인성이 보장되는 분산된 최적 강인 PI제어기 설계방법을 제안하고자 한다.

• 한국정밀공학회지
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• 제16권1호통권94호
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• pp.265-271
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• 1999

In the feed drive systems or the spindle systems of machine tools that consist of many mechanical components, a torsional vibration is often generated because of its elastic elements in torque transmission-Generally, the accuracy of motion control system is strongly influenced by the dynamic behavior of coupled transmission components Especially, a torsional vibration caused by the elasticity of mechanical elements might deteriorate the quick movement of system and lead to shorten the life time of the mechanical transmission elements. So, it is necessary to analyze the electromechanical system mathematically to optimize the dynamic characteristics of the feed m1d spindle system. In this paper, based on the DC motor model, a model of electro-drive system with motor has been developed and an optimal criterion for tuning the gain of speed controller is discussed. The frequency bandwidth of the system and the damping ratio in time domain are optimal design specifications for the gain adjustment speed controller. The gains of PI speed controller are then derived from the bandwidth and damping ratio, and those relationships have been classified.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권2호
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• pp.184-189
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• 2014

In this paper, a new design method of vibration suppression controller for multi-inertia (especially, 3-ineritia) resonance systems is proposed. The controller consists of a digital fuzzy controller for speed loop and a digital PI controller for current minor loop. The three scaling factor of the fuzzy controller and two PI controller gains are determined by Differential Evolution (DE). The DE is one of optimization techniques and a kind of evolutionary computation technique. In this paper, we have applied the DE/rand/1/bin strategy to design the optimal controller parameters. Comparing with the conventional design algorithm, the proposed method is able to shorten the time of the controller design to a large extent and to obtain accurate results. Finally, we confirmed the effectiveness of the proposal method by the computer simulations.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.602-603
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• 2010

This paper presents a comparison and evaluation between different anti-windup proportional-integral (PI) controller strategies used in variable-speed motor drives, and the anti-windup methods are to the speed control of a vector-controlled induction motor driven by a pulse width modulated (PWM) voltage-source inverter (VSI). The simulation results are compared for the different operating conditions and the characteristic of speed response has been analyzed in order to obtain the optimal performance of anti-windup PI controller method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1155-1157
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• 2002

This paper presents the use of a simple genetic algorithm for the tuning of a proportional-integral speed controller for an induction motor drive. The influence of population size, generation number and rate of mutation on the convergence of the genetic algorithm is investigated. On Matlab/Simulink environment, this paper proposes an optimal GA-PI controller of indirect vector control for induction motor drive system. The simulation results verify that the system has a more robust to the parameter variation than classical PI controller.

• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.715-723
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• 2016

This paper proposes a design of optimal PI(D) controller for brushless DC (BLDC) motor speed control by the particle swarm optimization (PSO), one of the powerful metaheuristic optimization search techniques. The proposed control system is implemented on the TMS320F28335 DSP board interfacing to MATLAB/SIMULINK. With Back EMF detection, the proposed system is considered as a class of sensorless control. This scheme leads to the speed adjustment of the BLDC motor by PWM. In this work, the BLDC motor of 100 watt is conducted to investigate the control performance. As results, it was found that the speed response of BLDC motor can be regulated at the operating speed of 800 and 1200 rpm in both no load and full load conditions. Very satisfactory responses of the BLDC system can be successfully achieved by the proposed control structure and PSO-based design approach.

• Transactions on Electrical and Electronic Materials
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• 제18권3호
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• pp.129-135
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• 2017

This paper introduces a design and a simulation of a hybrid active power filter (HAPF) for harmonics reduction given an ideal supply source. The synchronous reference frame method has been used here to identify the reference currents. The proposed HAPF uses a new artificial- intelligence technique called Particle Swarm Optimization (PSO) for tuning the parameters of a proportional and integral controller called PI-PSO. The PI-PSO controller is used to archive optimality for the DC-link voltage of the HAPF-inverter. The hysteresis non-linear current control method is used in this approach to compare the extracted reference and the actual currents in order to generate the pulse gate required for the HAPF. Results obtained by simulations with Matlab/Simuling show that the proposed approach is very flexible and effective for eliminating harmonic currents generated by the non-linear load with the HAPF based PSO tuning.