전압 직렬보상 방식 디지털 제어 교류 저전압보상기

정강률 한국정보기술학회 2023 한국정보기술학회논문지 Vol.21 No.12

This paper presents the digital-controlled AC low-voltage compensator with voltage series compensation method. The proposed AC low-voltage compensator compensates for the magnitude of the AC load input voltage, which is the final output voltage, with the voltage series compensation method using a power circuit topology consisting of a pulse-width modulation(PWM) AC-AC power converter and a compensating transformer. To this end, the proposed low-voltage compensator simply feeds back the magnitude of AC load input voltage through a circuit consisting of a current-type voltage transformer, a diode full-bridge rectifier, and a resistor/capacitor. Additionally, using a micom, it converts the feedback voltage to a digital value through A/D conversion and easily controls the entire system. This paper first briefly describes the operating principle of the power converter applied to the proposed low-voltage compensator and explains the control method of low-voltage compensation and the feedback method of final output voltage. Then, the driving method of the bidirectional power semiconductor switch of power converter is explained, and the implementation feasibility and good operating characteristics of the proposed low-voltage compensator are validated through the experimental results of the prototype.

높은 역률을 가지는 단순 구조 LED 구동 전력컨버터

정강률,Jeong, Gang-Youl 한국전기전자학회 2018 전기전자학회논문지 Vol.22 No.3

This paper proposes the simple structure LED-driving power converter with high power factor. As the proposed power converter combines the PFC boost converter and the conventional flyback converter into only one power conversion circuit, it simplifies the structure of LED-driving power converter. Thus the proposed converter is controlled using only one PWM controller IC, and it achieves high power factor, constant output voltage/current and cost-effectiveness. Therefore the proposed converter is suitable for the industry production and utilization of LED-light-system. In this paper, the operation analysis and design example of the proposed converter are explained, briefly. Also experimental results of the prototype that is implemented based on the designed circuit parameters are shown to validate operation characteristics of the proposed converter. 본 논문에서는 높은 역률을 가지는 단순 구조 LED 구동 직류 전력컨버터를 제안한다. 제안한 전력컨버터는 PFC 부스트 컨버터와 전통적인 플라이백 컨버터를 오직 하나의 전력변환 회로로 병합함으로써 LED 구동 전력컨버터의 구조를 단순화한다. 그리하여 제안한 컨버터는 오직 하나의 PWM 제어기 IC를 이용하여 제어되고 높은 역률과 정출력 전압/전류 및 제작비용의 효율성을 달성한다. 따라서 제안한 컨버터는 LED 조명시스템의 산업 생산과 이용에 적합하다. 본 논문에서는 제안한 컨버터의 동작분석과 설계예시를 간단하게 설명한다. 또한 설계된 회로파라미터들에 근거하여 제작된 프로토타입의 실험결과를 통하여 제안한 컨버터의 동작특성을 입증한다.

디지털 제어 LLC 직렬공진 하프브리지 직류-직류 전력변환기

정강률 한국정보기술학회 2023 한국정보기술학회논문지 Vol.21 No.6

This paper presents the digital-controlled LLC(Inductor-Inductor-Capacitor) series-resonant half-bridge DC-DC power converter. The proposed power converter performs high-efficiency DC-DC power conversion by applying the LLC series-resonant circuit consisting of the inductor-inductor-capacitor to the power topology of conventional half-bridge DC-DC power converter. In addition, the proposed converter operates in a multi-resonance method forming an LLC or LC(Inductor-Capacitor) series-resonant circuit for each operation mode, and digitally and simply controls voltage and current using a microcontroller. In this paper, first, the operation principle of the power circuit of proposed power converter is described separately for each operation mode. And the feedback technique and the digital control method by the microcontroller of the output voltage and current are explained, and then the driving technique of power semiconductor switch is described. Also, the feasibility and operation characteristics of the proposed converter are shown through the experimental results using a prototype converter. The maximum efficiency of the prototype converter was measured at about 94%.

자기구동 동기정류기를 이용한 고효율 풀브리지 DC-DC 컨버터

정강률 한국정보기술학회 2014 한국정보기술학회논문지 Vol. No.

This paper presents a high efficiency full-bridge DC-DC converter using a self-driven synchronous rectifier. The proposed converter achieves high efficiency using the pulse-width modulation (PWM) phase shift (PS) switching and the synchronous rectifier technique that reduce losses of the primary and secondary sides of converter, respectively. In particular, the converter secondary rectifier uses the full-wave synchronous rectifier by a center-tap typed transformer, where the self-driven method is applied for driving itself and thus its circuit and operation are made to be simplified. Thus the efficiency of the proposed full-bridge DC-DC converter is more improved about 4% than that of the conventional full-bridge DC-DC converter in the total load range, averagely. These improved results are shown through the experimental results of the prototype converter that is designed and implemented according to the operational principles explained in this paper. 본 논문에서는 자기구동 동기정류기를 이용한 고효율 풀브리지 DC-DC 컨버터를 제안한다. 제안하는 컨버터는 펄스폭변조(PWM; Pulse-Width Modulation) 위상시프트(PS; Phase Shift) 스위칭과 동기정류기 기법을 이용하여 컨버터 일차측과 이차측의 손실을 각각 감소시킴으로써 고효율을 달성한다. 특히 컨버터 이차측의 정류기는 센터탭 형태의 변압기에 의한 전파형 동기정류기를 이용하는데, 이 동기정류기의 구동을 위하여 자기구동 방식을 적용함으로써 회로와 그 동작이 간단하게 되도록 하였다. 그리하여 제안한 풀브리지 DC-DC 컨버터는 전체 부하영역에서 전통적인 풀브리지 DC-DC 컨버터보다 평균 약 4% 정도의 효율이 향상되었다. 이러한 향상된 결과는 본 논문에서 설명된 동작원리에 따라 설계되고 제작된 프로토타입 컨버터의 실험결과로 보인다.

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.

클램핑모드 부스트 인덕터를 이용한 고승압 디지털 제어 직류 전력변환기

정강률 한국정보기술학회 2022 한국정보기술학회논문지 Vol.20 No.7

This paper presents the high step-up digital-controlled DC power converter using the clamping-mode boost inductor. The clamping-mode boost inductor consists of the magnetically coupled inductor and simple clamping circuit. The proposed power converter using this has a very high input-output step-up-ratio, and the switch voltage stress is reduced. The proposed power converter is controlled by the digital control method using the one-chip microcontroller, so the control circuit is simple. In this paper, the operation principle of the power circuit of proposed power converter is explained briefly, and the digital control method applied to its controller is introduced shortly. And the main power circuit parameters of prototype power converter designed based on the given specifications and the operation principle are shown, and the operation characteristics of proposed power converter are validated through the experimental results of the prototype implemented with these parameters. The total input/output efficiency at the rated output of the proposed power converter prototype was measured to be about 92%, and the switch voltage stress was reduced by about 30% compared to the conventional method. 본 논문에서는 클램핑모드 부스트 인덕터를 이용한 고승압 디지털 제어 직류 전력변환기를 제안한다. 클램핑모드 부스트 인덕터는 자기적으로 결합한 인덕터와 간단한 클램핑 회로로 구성된다. 이를 이용한 제안한 전력변환기는 입출력 승압비가 매우 높으며, 스위치 전압스트레스는 저감된다. 제안한 전력변환기는 단일칩 마이크로컨트롤러를 이용하여 디지털 제어 기법에 의해 제어되므로 제어회로가 단순하다. 본 논문에서는 제안한 전력변환기의 전력회로의 동작원리를 간략하게 설명하고 제어기에 적용된 디지털 제어 기법에 관해 간단하게 소개한다. 그리고 주어진 사양과 동작원리에 근거하여 설계된 시제품 전력변환기의 주요 전력회로 파라미터를 제시하고, 이 파라미터로 제작된 시제품의 실험 결과로써 제안한 전력변환기의 동작 특성을 입증한다. 제안한 전력변환기 시제품의 정격출력 시의 전체 입출력 효율은 약 92% 정도로 측정되었으며, 스위치 전압스트레스는 기존 방식에 비해 약 30% 정도 감소하였다.

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.

싱글칩 마이크로컨트롤러를 이용한고효율 공진형 플라이백 전력변환기

정강률 한국전기전자학회 2020 전기전자학회논문지 Vol.24 No.3

This paper presents a high efficiency resonant flyback converter using a single-chip microcontroller. The proposedconverter primary performs the resonant switching by applying the asymmetrical pulse-width modulation (APWM) tothe half-bridge power topology. And the converter secondary uses the diode flyback rectifier as its power topology andoperates with the zero current switching (ZCS). Thus the proposed converter achieves high efficiency. The total structureof proposed converter is very simple because it uses a single-chip microcontroller and bootstrap circuit for its control anddrive, respectively. First, this paper describes the converter operation according to each operation mode and shows itssteady-state analysis. And the software control algorithm and drive circuits operating the proposed converter areexplained. Then, the operation characteristics of proposed converter are shown through the experimental results of animplemented prototype based on each explanation. 본 논문에서는 싱글칩 마이크로컨트롤러를 이용한 고효율 공진형 플라이백 전력변환기를 제안한다. 제안한 전력변환기의1차측은 하프브리지의 전력구조에 비대칭펄스폭변조(APWM:Asymmetrical Pulse-Width Modulation)을 적용하여 공진형 스위칭을 수행한다. 그리고 2차측은 다이오드 플라이백정류기 전력구조를 이용하고 영전류스위칭(ZCS:Zero Current Switching)으로 동작한다. 그리하여 제안한 컨버터는 고효율을 달성한다. 제안한 컨버터는 제어와 구동을 위하여 싱글칩 마이크로컨트롤러와 부트스랩 회로를 각각 이용하므로 전체적 구조가 매우 간단하다. 본 논문에서는 먼저, 제안한 전력변환기의 전력회로의 동작을 동작모드 별로 설명하고 정상상태 해석을 보인다. 그리고 제안한 전력변환기를 동작시키는 소프트웨어 제어 알고리즘과 구동회로에 관하여 설명하며, 그 후 각 설명에 근거하여 제작된 프로토타입의 실험결과를 통하여 제안한 전력변환기의 동작 특성을 보인다.

유도전동기의 공진 문제를 해결한 새로운 V/f 제어 기법

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

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