회전자 자속 추정을 이용한 센서리스 유도전동기 제어

정강률 순천향대학교 부설 산업기술연구소 2004 순천향 산업기술연구소논문집 Vol.10 No.1

This paper proposes a speed-sensorless induction motor control system using a rotor flux estimation. To explain the proposed sensorless control, this paper describes and induction motor model in the synchronous reference frame for the vector control. The rotor flux is indirectly estimated by the rotor flux observer using the reduced-dimensional state estimator technique instead of directly measuring the rotor flux. The estimated rotor speed is obtained directly from the electrical frequency, the slip frequency, and the rotor speed compensation with the estimated q-axis rotor flux. To precisely estimate the rotor flus, the actual value of the stator resistance, whose actual variation is reflected, is derived. An implementation of pulse-width modulation (PWM) pulses using an effective space vector modulation (SVM) is briefly mentioned. For fast calculation and improved performance of the proposed algorithm, all control functions are implemented in software using a digital signal processor (DSP) with its environmental circuits. Also, it is shown through experimental results that the proposed system gives good performance for the speed-sensorless induction motor control.

유도전동기의 공진 문제를 해결한 V/f 제어 기법

정강률 순천향대학교 부설 산업기술연구소 2003 순천향 산업기술연구소논문집 Vol.9 No.1

This paper proposes the novel V/f control method to improve the stability of a V/f controlled induction motor drive system. The novel conventional V/f control method used in the proposed novel V/f control method is a vector-based method that is slightly different from the conventional V/f control method. The proposed control method uses a dynamic current compensator to improve the stability of a V/f controlled induction motor drive system. This novel method is easy to implement and completely eliminates the motor oscillation phenomenon causing the instability of a V/f controlled induction motor drive system. Additionally, this paper analyzes theoretically the instability of a V/f controlled induction motor drive system and shows the validity of the proposed V/f control method through simulation and experimental results.

빠른 동특성을 가지는 병렬 능동필터에 의한 무효전력 보상 기법

정강률 순천향대학교 교수학습개발센터 2005 순천향 산업기술연구소논문집 Vol.11 No.1

This paper proposes a compensation method of the reactive power by the shunt active filter with fast dynamics that can eliminate the harmonic currents included in line currents without computation of harmonic current components. A current controller with fast dynamics for an active filter is described. Harmonic currents are directly controlled without the need for sensing and computing the harmonic current of the load current, thus simplifying the control system. Current compensation is done in the time domain, allowing a fast time response. The DC voltage control loop keeps the voltage across the DC capacitor constant. High power factor control by an active filter is described. All control functions are implemented in software using a single-chip microcontroller, thus simplifying the control circuit. Any current-controlled synchronous rectifier can be used as a shunt active filter through only the simple modification of the software and the addition of current sensors. It is shown through experimental results that the proposed controller gives good performance for the shunt active filter.

유도전동기의 공진 문제를 해결한 새로운 V/f 제어 기법

정강률 순천향대학교 산업기술연구소 2003 순천향 산업기술연구소논문집 Vol.9 No.1

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조광제어 기능을 가진 냉음극형형광램프 안정기

이재민,정강률 순천향대학교 산업기술연구소 2007 순천향 산업기술연구소논문집 Vol.13 No.1

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새로운 동기정류기 이용한 고효율 하프브리지 DC-DC 컨버터

유두희,정강률 순천향대학교 부설 산업기술연구소 2007 순천향 산업기술연구소논문집 Vol.13 No.1

This paper presents a high efficiency half-bridge dc-dc converter using a novel synchronous rectifier. After conventional self-driven synchronous rectifier technique applied to each conventional converter is briefly reviewed, the new topological self-driven synchronous rectifier applied to the proposed converter is briefly described. The new topological synchronous rectifier increases the system efficiency using low on-resistance of its switches and its switch conduction time extension to the whole switching period, which is one of the characteristics of the asymmetrical half-bridge converter. The synchronous rectifier type used in the proposed converter is a little modified type of the conventional synchronous rectifier used in the conventional asymmetrical half-bridge converter, which changes the transformer structure and synchronous rectifier switch connection. The operational principle of the proposed half-bridge dc-dc converter is explained, and according to this, a design consideration is shown. As the proposed converter utilizes the transformer leakage inductance as the resonant inductance, its structure is more simplified. The circuit operation and mathematical analysis of the proposed converter are given in detail. Also it is shown through the experimental results that the proposed converter operates excellently as a high efficiency converter.

Simple High Efficiency Full-Bridge DC-DC Converter using a Series Resonant Capacitor

Gang-Youl Jeong,Su-Han Kwon,Geun-Yong Park 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.1

This paper presents a simple high efficiency full-bridge DC-DC converter using a series resonant capacitor. The proposed converter achieves the zero voltage switching of the primary switches under a wide range of load conditions and reduces the high circulating current in the freewheeling mode using the leakage resonant inductance and the series resonant capacitor. Thus, the proposed converter overcomes the drawbacks of the conventional full-bridge DC-DC converter and improves its overall system efficiency. Its structure is simplified by using the leakage inductance of the transformer as the resonant inductance and omitting the DC output filter inductance. Also it can operate over a wide range of input voltages. In this paper, the operational principle, analysis and design example are described in detail. Finally, the experimental results from a 650W (24V/27A) prototype are demonstrated to confirm the operation, validity and features of the proposed converter.

Improved Single-Stage AC-DC LED-Drive Flyback Converter using the Transformer-Coupled Lossless Snubber

Jeong, Gang-Youl,Kwon, Su-Han The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.3

This paper presents an improved single-stage ac-dc LED-drive flyback converter using the transformer-coupled lossless (TCL) snubber. The proposed converter is derived from the integration of a full-bridge diode rectifier and a conventional flyback converter with a simple TCL snubber. The TCL snubber circuit is composed of only two diodes, a capacitor, and a transformer-coupled auxiliary winding. The TCL snubber limits the surge voltage of the switch and regenerates the energy stored in the leakage inductance of the transformer. Also, the switch of the proposed converter is turned on at a minimum voltage using a formed resonant circuit. Thus, the proposed converter achieves high efficiency. The proposed converter utilizes only one general power factor correction (PFC) control IC as its controller and performs both PFC and output power regulation, simultaneously. Therefore, the proposed converter provides a simple structure and an economic implementation and achieves a high power factor without the need for any separate PFC circuit. In this paper, the operational principle of the proposed converter is explained in detail and the design guideline of the proposed converter is briefly shown. Experimental results for a 40-W prototype are shown to validate the performance of the proposed converter.

Improved Single-Stage AC-DC LED-Drive Flyback Converter using the Transformer-Coupled Lossless Snubber

Gang-Youl Jeong,Su-Han Kwon 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.3

This paper presents an improved single-stage ac-dc LED-drive flyback converter using the transformer-coupled lossless (TCL) snubber. The proposed converter is derived from the integration of a full-bridge diode rectifier and a conventional flyback converter with a simple TCL snubber. The TCL snubber circuit is composed of only two diodes, a capacitor, and a transformer-coupled auxiliary winding. The TCL snubber limits the surge voltage of the switch and regenerates the energy stored in the leakage inductance of the transformer. Also, the switch of the proposed converter is turned on at a minimum voltage using a formed resonant circuit. Thus, the proposed converter achieves high efficiency. The proposed converter utilizes only one general power factor correction (PFC) control IC as its controller and performs both PFC and output power regulation, simultaneously. Therefore, the proposed converter provides a simple structure and an economic implementation and achieves a high power factor without the need for any separate PFC circuit. In this paper, the operational principle of the proposed converter is explained in detail and the design guideline of the proposed converter is briefly shown. Experimental results for a 40-W prototype are shown to validate the performance of the proposed converter.

Simple High Efficiency Full-Bridge DC-DC Converter using a Series Resonant Capacitor

Jeong, Gang-Youl,Kwon, Su-Han,Park, Geun-Yong The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.1

This paper presents a simple high efficiency full-bridge DC-DC converter using a series resonant capacitor. The proposed converter achieves the zero voltage switching of the primary switches under a wide range of load conditions and reduces the high circulating current in the freewheeling mode using the leakage resonant inductance and the series resonant capacitor. Thus, the proposed converter overcomes the drawbacks of the conventional full-bridge DC-DC converter and improves its overall system efficiency. Its structure is simplified by using the leakage inductance of the transformer as the resonant inductance and omitting the DC output filter inductance. Also it can operate over a wide range of input voltages. In this paper, the operational principle, analysis and design example are described in detail. Finally, the experimental results from a 650W (24V/27A) prototype are demonstrated to confirm the operation, validity and features of the proposed converter.