고조파 전류 제거를 위한 전력용 능동 필터 연구

鄭敎範 홍익대학교 산업기술연구소 2003 産業技術 Vol.13 No.-

In order to reduce efficiently the harmonic currents caused by the switching loads and to improve the whole performance of a three-phase four-wire power system, this paper investigates the three-phase four-wire active power filter. The topology of active power filter in the three-phase four-wire power system, the switching algorithm of active power filter using abc/αβγ transformation, and the hysteresis control for reducing harmonic currents in three-phase lines and a neutral line are studied. The performances of the active power filter are proved through the computer simulation study.

유도전동기의 속도제어를 위한 회전자 저항 추정에 관한 연구

鄭敎範,김혁수 홍익대학교 산업기술연구소 2000 産業技術 Vol.10 No.-

This paper investigates Kalman Filter as the rotor resistance esitmator for the speed sensorless vector control of an induction machine. Computer simulations are performed to prove the usefulness of the Kalman filters as the rotor resistance 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 shows the roboustness to the noises in the measurement signals and the excellent characteristics for the rotor resistance estimator under the various operating conditions.

싸이리스터 제어 직렬 콘덴서의 고조파 특성 연구

鄭敎範 홍익대학교 산업기술연구소 1998 産業技術 Vol.8 No.-

In order to understand the operational characteristics of the multi-module. Thyristor Controlled Series Condensor, this paper performs the analysis of the harmonic characteristics the stability calculation and the EMTP simulation of TCSC power transmission system. For the harmonic analysis, the Fourier series representation of the switching action of thyristors of TCSC modules and the bisection algorithm in numerical analysis to find the thyristor using the results of harmonic analysis and the theory of Poincare mapping for the nonlinear discrete periodic dynamic system. The EMTP simulation study performed with detailed power system component models and controller models proves the harmonic analysis and the stability calculation correct.

퍼지제어기를 이용한 풍력발전용 이중여자 유도기의 출력제어

鄭敎範 弘益大學校 産業技術硏究所 2007 産業技術 Vol.17 No.-

Recently many researchers have been interested in the various renewable energy sources because of the environmental pollution. From the researches for utilizing the clean energy, the electric generation of the wind power has been proved to be economically competitive and technically realizable. In this paper, the double-fed induction machine for the wind power generation is investigated because it has more advantages in size and control when compared to other type electric machines for the wind power generation. The dynamic characteristics of the double-fed induction machine is analyzed with the dq-axis transformation of the electric and mechanical equations and the output power controller is designed with the vector control and the fuzzy theory. PSIM simulations of the wind power generation system of the double-fed induction machine are performed to prove the feasibility of the designed controller.

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.

동기정류기를 이용한 펄스공진형 플라이백 컨버터

鄭敎範 弘益大學校 産業技術硏究所 2005 産業技術 Vol.15 No.-

This research proposes a new converter for transferring the energy of a low-voltage AC voltage source to a DC load. The converter has two stages in power processing; The first stage is a MOSFET full-bridge rectifier for the AC-to-DC conversion. The second stage is a flyback converter for converting low DC voltage to high DC voltage. High frequency transformer is used for the electrical isolation. The magnetizing inductance of the transformer makes a resonant circuit with the output capacitor of the ac voltage source. In order to increase the efficiency of the converter, the zero voltage switching and zero current switching with LC resonance is chosen and MOSFETs are on and off in the 3rd quadrant. The operation of the converter is analytically studied and proved in a computer simulation.

전력변환장치와 부하 특성에 따른 Solar Power System의 안정도 연구

鄭敎範 홍익대학교 산업기술연구소 1997 産業技術 Vol.7 No.-

The equilibrium point of the solar power system have their own particular characteristics determined by the control mode of the power conditioning system. The stability of utility-interactive solar power system with a line -commutated converter is analyzed at various equilibrium points using the state-plane analysis technique. and the stability of utility-interactive solar power system with a forced-commutated converter is also analyzed and compared to that of the line commutated case. The stable operation region of the solar power system is identified after the behavior of the states near the various equilibrium points analyzed with a functional model of the solar power system.

밧데리 충전을 위한 새로운 AC/DC 컨버터에 대한 연구

鄭敎範,金台根 弘益大學校 産業技術硏究所 2004 産業技術 Vol.14 No.-

New AC/DC power converter for battery charging is proposed. The converter with four MOSFET, a diode and an inductor transfers energy from AC current source to DC battery. In order to make the converter efficient and compact, the inductance as small as possible is chosen. The converter has a ultimately short interval of turning MOSFETs on, which makes the parasitic capacitors of MOSFETs and a diode take effects on the converter operation. The analysis of the converter operation and the calculation of the energy losses are in detail performed, which is proved with the computer simulation study.

약한 계통에 연계된 HVDC 시스템 특성 연구

鄭敎範 홍익대학교 산업기술연구소 2002 産業技術 Vol.12 No.-

HVDC system is a DC power transmission system. Compared to conventional three-phase transmission with alternating current, HVDC transmission has both advantages and disadvantages. Specially HVDC system is much more economic for the bulk power transmission over long distances than the ac power transmission system. However, due to the natural commutation, the HVDC system requires a large amount of reactive power compensation. HVDC system interconnecting weak AC system encounters more difficulties than with strong AC system. Any small perturbations in the weak AC system may result in such disturbances that proper operation of the converter is severely affected. A major problem is commutation failure for inverters of HVDC system. In order to find the steady-state operating condition of HVDC system interacting with AC power system, the load flow calculation of AC/HVDC system is performed. For the calculation, each generating unit is modeled by an equivalent voltage source and coupled impedance. The rectifier station is modeled by the controlled DC voltage source. EMTP simulation of the AC/HVDC system is also performed to verify the result of the load flow calculation.

비대칭 반브리지 DC/DC 컨버터 연구

鄭敎範,金한들 홍익대학교 산업기술연구소 2006 産業技術 Vol.16 No.-

This research proposes a design method of the controller to regulate the output voltage of an asymmetric half-bridge(AHB) DC/DC converter, which transfers the energy from a high-voltage DC source to a low-voltage DC load. The steady-state characteristics of the AHB DC/DC converter is analyized using the averaged state equation. The dynamic equation are derived with the linearization and the samll pertubation. The loop gain method is used to design the output voltage regualtor. The performance of the regulator of the AHB DC/DC converter is analytically studied in a computer simulation using PSIM.