중앙집중형 전력계통에서의 전력품질 규제

정교범 전력전자학회 2005 전력전자학회지 Vol.10 No.6

누적방지 기법을 적용한 3상 4선식 능동전력필터 시스템의 직류전압 제어

정교범 전력전자학회 2003 전력전자학회 논문지 Vol.8 No.2

This paper investigates the application of the anti-windup scheme to control DC voltage of the three-phase four-wire active power filter, installed in a three-phase four-wire power system. In order to reduce efficiently the harmonic currents caused by the switching loads and to improve the whole performance of the power system, the DC voltage of the three-phase four-wire active power filter should be properly controlled. PI controller can be applied to the DC voltage controller of the three-phase four-wire active power filter. However, a large error input to PI controller leads to a windup phenomenon which deteriorate the dynamic characteristics of the DC voltage controller. Therefore, the application of the anti-windup scheme for the DC voltage controller is proposed and the improved performances of the anti-windup DC voltage controller are proved through the computer simulation study. 본 논문은 3상 4선식 전력시스템내의 고조파전류 및 중성선에 흐르는 영상 전류를 저감하기 위한 3상 4선식 능동전력필터의 직류전압 제어를 위한 누적방지기법 적용에 관한 연구를 수행한다. 비선형 스위칭 부하에 의해 발생한 고조파 전류를 효율적으로 저감하고 전력시스템의 전체 성능을 개선하기 위해서, 전력시스템의 운전 특성에 따라 3상 4선식 능동전력필터의 내부 직류전압을 제어할 필요가 있다. 직류전압 제어를 위해서 일반적으로 PI 제어기를 사용하나, 적분기에 의한 누적 오차는 직류전압 제어기의 동특성에 영향을 준다. 따라서 본 논문은 누적방지 기법의 사용을 제안하며, 3상 4선식 능동전력필터의 직류 전압 제어기의 동특성이 개선됨을 컴퓨터 시뮬레이션을 통하여 증명한다.

Takagi-Sugeno Fuzzy Integral Control for Asymmetric Half-Bridge DC/DC Converter

정교범 한국지능시스템학회 2007 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.7 No.1

In this paper, Takagi-Sugeno (TS) fuzzy integral control is investigated to regulate the output voltage of an asymmetric half-bridge (AHB) DC/DC converter; First, we model the dynamic characteristics of the AHB DC/DC converter with state-space averaging method and small perturbation at an operating point. After introducing an additional integral state of the output regulation error, we obtain the 5th-order TS fuzzy model of the AHB DC/DC converter. Second, the concept of the parallel distributed compensation is applied to design the fuzzy integral controller, in which the state feedback gains are obtained by solving the linear matrix inequalities (LMIs). Finally, simulation results are presented to show the performance of the considered design method as the output voltage regulator and compared to the results for which the conventional loop gain method is used.

기생성분을 고려한 저전압 AC 전류원 충전회로의 동작모드 해석

정교범,Chung Gyo-Bum 전력전자학회 2005 전력전자학회 논문지 Vol.10 No.1

A new converter to transfer energy from a low-voltage AC current source to a battery is proposed. It is focused to find operational modes of the converter. The low-voltage AC current source is an equivalent of the piezoelectric generator, which converts the mechanical energy to the electric energy. The converter consists of a full-bridge MOSFET rectifier and a MOSFET boost converter in order to make the converter small and efficient. The operational principle and modes of the converter are investigated with the consideration of effects of the parasitic capacitances of MOSFETs and diode. The results are proved with simulation studies using PSIM and Pspice. 압전소자를 이용한 마이크로발전기를 모델링한 저전압 AC 전류원으로부터 밧데리 충전을 위한 에너지 변환회로를 제안하고, 동작모드를 해석한다. 전체 시스템의 소형화 및 고효율화를 추구하기 위해서, MOSFET 풀브리지 정류기와 부스트 컨버터의 토폴로지를 채택하였다. 제안된 컨버터 시스템의 동작원리 및 동작모드를 스위칭 소자의 기생캐패시턴스를 고려하여 해석하고, 시뮬레이션을 통해 해석결과를 검증하였다.

Investigation of PID Fuzzy Controller for Output Voltage Regulation of Current-Doubler-Rectified Asymmetric Half-Bridge DC/DC Converter

정교범,Kang-Hyun Yi,Sang-Kyoo Han 전력전자학회 2007 JOURNAL OF POWER ELECTRONICS Vol.7 No.1

This paper investigates a PID fuzzy controller for output voltage regulation of a current-doubler-rectified asymmetric half-bridge (CDRAHB) DC/DC converter. The controller is a PD-type fuzzy controller in parallel with a linear integral controller. The PD type fuzzy controller is for providing the varying gain at the different operating conditions to regulate the output voltage. The linear integral controller is for removing the steady-state error of the output voltage. In order to show the outstanding dynamic characteristics of the proposed controller, PSIM simulation studies are carried out and compared to the results for which the conventional loop gain design method is used.

Application of Fuzzy PI Control Algorithm as Stator Power Controller of a Double-Fed Induction Machine in Wind Power Generation Systems

정교범,최재호 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.1

This paper addresses the output control of a utility-connected double-fed induction machine (DFIM) for wind power generation systems (WPGS). DFIM has a back-to-back converter to control outputs of DFIM driven by the wind turbine for WPGS. To supply commercially the power of WPGS to the grid without any problems related to power quality, the real and reactive powers (PQ) at the stator side of DFIM are strictly controlled at the required level, which in this paper is realized with the Fuzzy PI controller based on the field orientation control. For the Sinusoidal Pulse Width Modulation (SPWM) converter connected to the rotor side of DFIG to maintain the controllability of PQ at the state side of DFIM, the DC voltage of the DC link capacitor is also controlled at a certain level with the conventional Proportion-Integral (PI) controller of the real power. In addition, the power quality at the grid connected to the rotor side of DFIM through the back-to-back converter is maintained in a certain level with a PI controller of the reactive power. The controllers for the PQ at the stator side of DFIM, the DC link voltage of the back-to-back inverter and the reactive power at the grid connected to the rotor side of DFIM are designed and simulated in the PSIM program, of which the result verifies the performance of the proposed controllers.

싸이리스터제어 병렬보상기의 특성 연구

정교범 전력전자학회 1999 전력전자학회 논문지 Vol.4 No.4

본 논문은, 대표적인 FACTS기기중의 하나인 싸이리스터제어 병렬보상기의 특성 연구를 수행한다. 이를 위하여 푸리에 공간에서 전력조류 조건을 만족하는 싸이리스터 점호각을 수치해석적으로 구하고, 그 계산 결과를 이용하여 정상상태 및 고조파 특성을 해석하였다. 그리고, Poincare Mapping 이론을 이용한 스위칭 주파수영역에서 안정도 해석과 EMTP 시뮬레이션을 이용한 시평면상에서 해석결과의 검증 및 여러 운전점에서 과도응답특성의 비교연구를 수행하였다. This paper studies the operational characteristics of thyristor controlled shunt compensator in a simple power t transmission system. With Fourier series representation of the thyristor switching action and the system parameters, t the thyristor current equations are derived, which transmit the required real power of the simple power transmission s system. Bisection algorithm is used to solve the thyristor current equations, which informs the thyristor firing an밍e, t the thyristor conduction an밍e, the power flows and the harmonic characteristics. The stability analysis is performed w with the theory of Poincare mapping for the nonlinear discrete periodic dynamic system. EMTP simulations at the v various operating points show the transient characteristics of the thyristor controlled shunt compensator and C correspond to the results calculated with Fourier series representation and the stability analysis.

에너지 획득을 위한 AC/DC 공진형 펄스 컨버터의 연구

정교범,Khai D.T. Ngo 전력전자학회 2005 전력전자학회 논문지 Vol.10 No.3

A new resonant pulse converter for energy harvesting is proposed. The converter transfers energy from a low-voltage AC current to a battery. The low-voltage AC current source is an equivalent of the piezoelectric generator, which converts the mechanical energy to the electric energy. The converter consists of a full-bridge rectifier having four N-type MOSFETs and a boost converter having N-type MOSFET and P-type MOSFET instead of diode. Switching of MOSFETs utilizes the capability of the 3rd regional operation. The operational principles and switching method for the power control of the converter are investigated with the consideration of effects of the parasitic capacitances of MOSFETs. Simulation and experiment are performed to prove the analysis of the converter operation and to show the possibility of the μW energy harvesting. 압전소자를 에너지원으로 사용하여 자립형 전기전자시스템에 에너지를 공급하는 에너지 획득(Harvesting) 개념의 구현을 위하여, 새로운 AC/DC 공진형 펄스 컨버터를 제안한다. 컨버터는 정류기와 DC 컨버터의 2단계로 구성되었으며, AC/DC 변환을 위한 정류기는 MOSFET의 3상한 동작 특성을 이용하여 구현하고, N형 및 P형 MOSFETs을 사용하여 DC/DC 부스트 컨버터를 구현하였다. 제안된 컨버터 시스템의 동작원리 및 동작모드를 스위칭 소자의 기생캐패시턴스를 고려하여 해석하고, 시뮬레이션을 통하여 해석결과를 검증하였다. CMOS IC 칩으로 제작된 본 시스템의 실험 결과는 수십 uW 용량에서 에너지 획득 개념의 구현 가능성을 제시하였다.

Application of Fuzzy Integral Control for Output Regulation of Asymmetric Half-Bridge DC/DC Converter with Current Doubler Rectifier

정교범,Sun-Geun Kwack 전력전자학회 2007 JOURNAL OF POWER ELECTRONICS Vol.7 No.3

This paper considers the problem of regulating the output voltage of a current doubler rectified asymmetric half-bridge (CDRAHB) DC/DC converter via fuzzy integral control. First, we model the dynamic characteristics of the CDRAHB converter with the state-space averaging method, and after introducing an additional integral state of the output regulation error, we obtain the Takagi-Sugeno (TS) fuzzy model for the augmented system. Second, the concept of parallel distributed compensation is applied to the design of the TS fuzzy integral controller, in which the state feedback gains are obtained by solving the linear matrix inequalities (LMIs). Finally, numerical simulations of the considered design method are compared to those of the conventional method, in which a compensated error amplifier is designed for the stability of the feedback control loop.

칼만필터를 이용한 유도전동기의 속도추정

鄭敎範,李承眩 홍익대학교 산업기술연구소 1999 産業技術 Vol.9 No.-

This paper investigates Kalman Filter as the rotor speed esitmator for the speed sensorless vector control of an induction machine. The Kalman filters as the rotor speed esitmator are classified as full-order Extended Kalman Filter, a minimum-order Extended Kalman Filter and a reduced-model Extended Kalman Filter. Computer simulations are performed to prove the usefulness of the Kalman filters as the rotor speed esitmator for the speed sensorless vector control of the induction machine. In the simulation, the induction machine and the inverter using the switching space vector PWM algorithm are included. The Extended Kalman Filter for the speed sensorless vector control shows the roboustness to the noises in the measurement signals and the excellent characteristics for the rotor speed control under the various operating conditions. The characteristics of the Kalman Filters as the rotor speed estimator are compared to each other through the computer simulations. Comparing to Full-order Extended Kalman Filter, the minimum-order Extended Kalman Filter and the reduced-model Extended Kalman Filter have the advantages of fast computation due to the simplified modeling and also show the robustness to the measurement noises variation.