• Journal of Power Electronics
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• 제16권2호
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• pp.610-620
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• 2016

The compound active clamp zero voltage soft switching (CACZVS) three-phase power factor correction (PFC) converter has many advantages, such as high efficiency, high power factor, bi-directional energy flow, and soft switching of all the switches. Triple closed-loop PI controllers are used for the three-phase power factor correction converter. The control objectives of the converter include a fast transient response, high accuracy, and unity power factor. There are six parameters of the controllers that need to be tuned in order to obtain multi-objective optimization. However, six of the parameters are mutually dependent for the objectives. This is beyond the scope of the traditional experience based PI parameters tuning method. In this paper, an improved chaotic particle swarm optimization (CPSO) method has been proposed to optimize the controller parameters. In the proposed method, multi-dimensional chaotic sequences generated by spatiotemporal chaos map are used as initial particles to get a better initial distribution and to avoid local minimums. Pareto optimal solutions are also used to avoid the weight selection difficulty of the multi-objectives. Simulation and experiment results show the effectiveness and superiority of the proposed method.

• Journal of Power Electronics
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• 제12권1호
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• pp.104-112
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• 2012

In this paper a new method for the design of a simple PI controller is presented and it has been applied in the control of a Boost based PFC rectifier. The Strength Pareto evolutionary algorithm, which is based on the Pareto Optimality concept, used in Game theory literature is implemented as a multi-objective optimization approach to gain a good transient response and a high quality input current. In the proposed method, the input current harmonics and the dynamic response have been assumed as objective functions, while the PI controller's gains of the PFC rectifier (Kpi, Tpi) are design variables. The proposed algorithm generates a set of optimal gains called a Pareto Set corresponding to a Pareto Front, which is a set of optimal results for the objective functions. All of the Pareto Front points are optimum, but according to the design priority objective function, each one can be selected. Simulation and experimental results are presented to prove the superiority of the proposed design methodology over other methods.

• International Journal of Control, Automation, and Systems
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• 제4권2호
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• pp.155-164
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• 2006

This paper focuses on a new optimization technique of a fuzzy logic based proportional integral (FLPI) load frequency controller by the multiple tabu search (MTS) algorithm. Conventionally, the membership functions and control rules of fuzzy logic control are obtained by trial and error method or experiences of designers. To overcome this problem, the MTS algorithm is proposed to simultaneously tune proportional integral gains, the membership functions and control rules of a FLPI load frequency controller in order to minimize the frequency deviations of the interconnected power system against load disturbances. The MTS algorithm introduces additional techniques for improvement of the search process such as initialization, adaptive search, multiple searches, crossover and restart process. Simulation results explicitly show that the performance of the proposed FLPI controller is superior to conventional PI and FLPI controllers in terms of overshoot and settling time. Furthermore, the robustness of the proposed FLPI controller under variation of system parameters and load change are higher than that of conventional PI and FLPI controllers.

• Journal of Power Electronics
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• 제11권4호
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• pp.393-400
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• 2011

The main objective of this paper is to control the speed of Nonlinear Hybrid Electric Vehicle (HEV) by controlling the throttle position. Various control techniques such as well known Proportional-Integral-Derivative (PID) controller in conjunction with state feedback controller (SFC) such as Pole Placement Technique (PPT), Observer Based Controller (OBC) and Linear Quadratic Regulator (LQR) Controller are designed. Some Intelligent control techniques e.g. fuzzy logic PD, Fuzzy logic PI along with Adaptive Controller such as Self Organizing Controller (SOC) is also designed. The design objective in this research paper is to provide smooth throttle movement, zero steady-state speed error, and to maintain a Selected Vehicle (SV) speed. A comparative study is carried out in order to identify the superiority of optimal control technique so as to get improved fuel economy, reduced pollution, improved driving safety and reduced manufacturing costs.

• 전력전자학회논문지
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• 제22권1호
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• pp.1-8
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• 2017

The optimal gain design method of a three-phase boost converter is proposed in this study. The control system has a two-loop configuration, in which each controller is coupled closely; thus, the optimal design is difficult to achieve using conventional gain-tuning method. The proposed method is adopted to the MATLAB SISO TOOL software and is based on the controller requirements, which are phase margin and cut-off frequency of the open-loop system. The optimal proportional -integral gains can be designed easily using the proposed interactive method of the SISO TOOL. The performance of the proposed system is verified through simulation and experiments.

• 전력전자학회논문지
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• 제12권2호
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• pp.183-190
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• 2007

본 논문에서는 PWM 컨버터의 강인제어기를 제안한다. 제안된 컨버터제어기는 DC 출력전압 제어를 위한 PI 제어기와 입력전류를 전원과 동상인 정현파로 제어하기 위해 오차공간에서 제어 문제를 해결한 전류제어기로 구성되어있다. 종래에는 전류제어기의 설계과정에서 소자의 스위칭주파수 및 디지탈제어기의 샘플링 주파수 등을 고려하여 제어기 게인값에 대한 해를 구하는 과정에서 시행착오 방법을 사용하여야 했다. 그러나 제안된 제어기는 CRA 기법을 적용하여 원하는 응답속도 및 오버슈트를 가지도록 최적의 게인값을 설정하도록 하였다. 먼저 CRA 기법을 적용한 전류제어기 알고리즘을 설명하고 PSiM 시뮬레이션 및 실험을 통하여 제안된 제어기의 타당성을 검증한다.

• Journal of Power Electronics
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• 제12권2호
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• pp.305-316
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• 2012

The paper presents an accurate loss model based controller of an induction motor to calculate the optimal air gap flux. The model includes copper losses, iron losses, harmonic losses, friction and windage losses, and stray losses. These losses are represented as a function of the air gap flux. By using the calculated optimal air gap flux compared with rated flux for speed sensorless indirect vector controlled induction motor, an improvement in motor efficiency is achieved. The motor speed performance is improved using a fuzzy logic speed controller instead of a PI controller. The fuzzy logic speed controller was simulated using the fuzzy control interface block of MATLAB/SIMULINK program. The control algorithm is experimentally tested within a PC under RTAI-Linux. The simulation and experimental results show the improvement in motor efficiency and speed performance.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2301-2309
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• 2018

In a field-oriented vector-controlled permanent magnet synchronous motor (PMSM) control system, the d-axis current control loop can offer a free degree of freedom which can be used to improve control performances. However, in the industry the desired d-axis current command is usually set as zero without using the free degree of freedom. This paper proposes a method to use the degree of freedom for control performance improvement. It is assumed that both the inner loop proportional-integral (PI) current controller and the q-axis outer loop PI speed controller are tuned by the well-known tuning rules. This paper gives an optimal d-axis reference current command generator such that some useful performance indexes are minimized and/or a tradeoff between conflicting performance criteria is made. This paper uses a differential evolution algorithm to autotune the parameter values of the optimal d-axis reference current command generator. This paper implements the proposed control system in real time on a Texas Instruments TMS320F28335 floating-point DSP. This paper also gives experimental results showing the practicality and feasibility of the proposed control system, along with simulation results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.199-202
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• 1995

In the conventional $H_2$ design of PI controllers, the quadratic cost function includes only the plant output term and hence, the optimal controller often results in a very large plant input. In this paper, $H_{\infty}$ design methodology is combined with the conventional $H_2$ design to make a trade-off between the regulation of the plant input and the plant output in a systematic way.

• 전자공학회논문지S
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• 제36S권2호
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• pp.120-130
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• 1999

본 연구에서는 복권형 하이브리드 스테핑 전동기의 회전자 위치 함수로 주어지는 순시 상전류식을 유도하여 Laad Angle에 따른 순시 상전류값의 변화를 보이고, 특히 여자 펄스 인가후 ${\pi}/2$ 시점의 수닛 상전류값으로부터 회전자 위치 정보를 얻을 수 있음을 이론식 및 컴퓨터 시뮬레이션에 의해 확인하였다. 이러한 사실으로부터 복권형 하이브리드 스테핑 전동기의 폐루프 운전을 위해 회전자 위치 검출기를 사용하지 않고 전동기의 파라미터가 고려된 최적 Lead Angle이 실현된 여자 펄스를 생성시키는 제어기를 마이크로컨트롤러에 의해 구성하고 실험하였다. 구성된 제어기는 A/D 변환기, 프로그래머블 입.출력 타이머 및 전동기 속도에 대한 최적 Lead Angle 값을 갖는 변환 테이블 등의 기능을 갖는 마이크로컨트롤러와 또한 전동기의 속도와 여자 펄스 인가후 ${\pi}/2$ 시점의 순시 상전류값에 대한 정토오크 발생영역에 해당하는 Lead Angle 값을 갖는 변환 테이블을 위한 ROM 등으로 구성되어 외부 부가회로를 최소화하였으며, 전동기의 파라미터 등의 변화에 따른 제어량의 병환 테이블이 내용과 제어 S/W 에 의존함으로써 유연성을 확보하였다. 이와 같이 구성된 복권형 하이브리드 스테핑 전동기의 회전자 위 센서리스 최적 Lead Angle 시의 순시 상전류 파형과 유사한 파형을 얻음으로써 최적 Lead Angle 이 실현되었음을 확인할 수 있었다.