전류형 능동 전력필터를 위한 델터변조기법에 관한 연구

최규하,백형래,김한성 建國大學校 附設 産業技術硏究所 1992 논문집 Vol.17 No.-

Delta modulation technique for current-type active power filter is proposed which can not only eliminate the harmonic current but compensate the reactive power at the AC sides where the nonlinear loads are connected. The delta modulated current control can be used to improve both the response and the control capability of the injected compensating current for the active filter with constant current source. As a result the compensated ac line current becomes nearly sinusoidal and also the input power factor is improved roughly to unity.

One-Chip uP에 의한 CO₂가스메탈 아크용접기의 디지털 제어기 설계에 관한 연구

최규하,채영민,송성학,우동학,한광수,안기은 건국대학교 1997 學術誌 Vol.41 No.2

With the development of semiconductor devices, adaptation of microcontroller prevails in industrial area. But in arc welding industry, there has not been much progress in adoption microcontroller technology. Therefore, this paper shows the application of digital control technology to welding machine. This paper presents the design of microcontroller that is appropriate for three phase CO2 gas metal arc welding machine. By using microcontroller in CO2 gas metal arc welding machine, the overact cost can be reduced compared to analog type one. Also TMS370C850 microprocessor is used as overall microcontroller for the arc welding machine.

전력계통의 고조파 실태조사를 위한 설문서 설계에 관한 연구

최규하,신중린,임한석 建國大學校 附設 産業技術硏究所 1993 논문집 Vol.18 No.-

A design of survey form is studied for the investigations of technical aspects and/or social effects caused by harmonics on the electric power system of Korea. The survey form is aimed to have the function of investigation for the current status of harmonics problems on the power system, as well as the function of giving further understanding of the problems to the field engineers and customers in related sphere. The proposed survey form will give some contribution to build up nation-wide countermeasures to the harmonics problems.

순간전압강하 보상기능을 갖는 능동전력필터 시스템의 특성해석

최규하,채영민,강성곤 건국대학교 1995 學術誌 Vol.39 No.2

The conventional APF(Active Power Filter) system performs only function which is compensated for AC harmonics by injecting harmonic compensation current as well as reactive power component by PWM technique. This paper presents a new APF which provides the combined functions of instantaneous VDC(Voltage Drop Compensator) together with APF function , Because the structure of APF is similar to stand-alone UPS In parallel type. Therefore by the states of source voltage, This system fufills not only APF function but also VDC through mode transform algorithm. The control range of VDC sets from 10% to 70% voltage drop. In this paper inverter is operated by the hysteresis controller for the current control in APF and the voltage control in VDC which have the merits of the easy implementation and the fast response for the transient states. The power circuit is composed of voltage-fed IGBT inverter. Single-chip microprocessor plays an important role in controlling both functions. In addition with simulation result from ACSL(Advanced Continuous Simulation Language), experimental results are shown to verify the proposed idea for APF system.

전류형 능동필터시스템의 설계와 마이크로 프로세서 제어

崔圭夏 建國大學校 産業技術硏究所 1988 논문집 Vol.13 No.-

Current-fed active filters are used to eliminate the harmonics present at the input side of the nonlinear loads such as the rectifiers, inverters. The active filter has so much better characteristics than the conventional passive filter in the aspects of the harmonic elimination, stability, filter cost and structure. In this paper the theoretical studies on the current-fed filter are investigated and the design and the microprocessor control of the filter are performed experimentally on the basis of the computed results.

CO₂아크용접기를 위한 3상 전압형컨버터의 입력역률개선

최규하,최해룡,김홍성 건국대학교 산업기술연구원 2000 건국기술연구논문지 Vol.25 No.-

Diode rectifier has been widely used as preregulator in CO2 arc welding machine, which has an advantage of low cost in application field. One of the demerits of diode-bridge rectifiers, is the line-current harmonic caused by the nonlinear nature of rectifier operation. As it is linked to power utility, a disorder of other instruments can be burst out, and the reactive power degenerates the total system efficiency The adoption of voltage source PWM converters can be considered and it must catch the compromise of system performance and cost. So, in this paper voltage source converters which have single and six control switch respectively, are analyzed and confirmed through digital simulation and experiments. In addition the improved input characteristics of CO2 arc welding machine known as low power factor system with nonlinear property, are shown and evaluated compared to conventional one.

선형전압제어와 고조파제거를 위한 교류전압조정기의 새로운 스위칭 패턴

崔圭夏 건국대학교 1987 學術誌 Vol.31 No.2

A new switching pattern for AC voltage regulator is proposed which can perform both linear control of the fundamental voltage and complete elimination of the harmonic contents up to the specified order corresponding to the modulation number. Through digital computer simulation the overall characteristics such as the changes of switching points to a control variable, the harmonic components of voltage and current and the current ratio are investigated and the modified triangular carrier is derived for practical implementation.

회전자형 위치센서를 갖는 스위치드 릴럭턴스 전동기의 속도 제어

최규하,최기원,장도현 건국대학교 1996 學術誌 Vol.40 No.2

This paper describes the practical implementation of switched reluctance motor drive for a wide range of operation speeds. Turn-on/off angle of phase switches and magnitude of current depend upon the speed and load variations. The angle controller is designed with one-chip microprocessor 8051 for various real time applications. Turn-on/off angle is controlled by timer/counter mode 2 of 8051. Position sensor for SRM drive consists of the rotor shaped slot-disc and opto-interrupter. Algorithm to control the speed of SRM with rotor type position sensor and to maintain the speed under the changed load is proposed. Experiments are executed to verify the proposed algorithm.

인버터 구동 유도전동기의 가창소음 저감을 위한 새로운 펄스폭 변조기법

최규하,신우석,함연창 建國大學校 附設 産業技術硏究所 1992 논문집 Vol.17 No.-

The PWM inverter system are widely used to control the induction motor, and their switching frequency rises to the higher for better performances. But the upper should be limited for safe operation as well as switching loss reduction in the power transistor inverters. This makes the level of the audible noise much increased. In order to overcome such noise problem, a new PWM control technique is proposed in the power transistor inverters, of which carrier frequency is to change a according to the slope of the sine wave reference signal. As a result the frequency spectra are improved and hence the audible noise couble be reduced greatly.

직류측 병렬연계 시스템 적용을 위한 양방향 컨버터의 특성 해석

최규하,김홍성,김한성 건국대학교 산업기술연구원 1994 건국기술연구논문지 Vol.19 No.-

This paper describes DC side parallel joint system using bidirectional PWM converter. In the conventional DC side paralleled joint system the diode rectifiers have been used as AC-DC converter. These make the problems of low PF and plentiful harmonics with DC side filer and decrease the efficiency of solar cell. The bidirectional PWM converter is considered as the remedy for these problems. The proposed system is composed of the step-up chopper, the solar cell and the bidirectional PWM converter. The solar cell is connected to the de link of the converter through the step-up chopper which have a function of maximum power point tracker. The PWM converter has the function of current control and voltage regulator. The two-level PWM hysteresis method is used for the current control and P-I controller for the voltage regulator. Also both simulation results and experimental results are shown for verification and comparison.