3상4선식 컨버터의 독립전력제어 기반 능동수명제어 알고리즘

곽상신,응웬 민 호앙 대한전기학회 2022 전기학회논문지 Vol.71 No.7

Along with using renewable energy sources such as photovoltaic (PV), wind, and biomass, the power system structure has evolved and grown more complex in recent years. As a crucial part of power distribution, the three-phase converter plays a significant role; nevertheless, this does not account for the fact that various phase legs may experience different aging conditions. This study offers an active thermal control (ATC) concept for a two-level, three-phase, four-wire converter with balance circuit in order to delay the failure of the aged leg and the entire converter. The first ATC approach using the model predictive control (MPC) strategy is investigated to regulate the output current and balance the capacitor voltage. A modified cost function is proposed to improve the capacitor voltages balancing control capability. Additionally, the second ATC approach using a carrier-based pulse-width-modulation (CBPWM) method based per-phase voltage and current control is introduced. The achieved simulation and experiment results of both CBPWM and MPC schemes are presented to verify the performance of the ATC based per-phase power control for the two-level three-phase four-wire converter with balance circuit.

고조파 및 불평형 성분을 가지는 계통 환경에 따른 3상 펄스폭변조정류기 성능 비교 연구

곽상신,김동연,김재창 대한전기학회 2021 전기학회논문지 Vol.70 No.6

In this paper, the input and output performance of a three-phase pulse width modulation (PWM) rectifier operated by each of three different control techniques based on current control and power control in the grid with harmonics and unbalanced components are compared and analyzed. Regardless of the basic and high-efficiency types, the same current-controlled and power-controlled techniques showed similar performance in the harmonics and unbalanced grid conditions. In all grid conditions with harmonics and unbalanced components, the output voltage by the power-controlled rectifier has a lower ripple value than the output voltage by the current-controlled rectifier. Therefore, in terms of output voltage ripple, it is confirmed that the power-controlled rectifier shows more robust characteristics in harmonics and unbalanced grid condition.

청년 고용문제의 해법 찾기 ; 청년 일자리의 실태와 좋은 일자리 확대 방안

곽상신 한국노동사회연구소 2015 노동사회 Vol.184 No.-

고전계 노화 SiC-MOSFET 소자를 가지는 양방향 DC-DC 컨버터 특성 분석 연구

곽상신,정재윤 대한전기학회 2022 전기학회논문지 Vol.71 No.9

Recently, the use of Silicon-carbide Metal Oxide Semiconductor (SiC-MOSFET) with high frequency and low loss characteristics is increasing in power conversion systems. SiC-MOSFET is aged due to the kinetic energy of electrons and thermal stress. In this case, the aged SiC-MOSFET may not perform as expected and may cause a failure of the power conversion system. This can lead to personal injury and property damage, so it is very important to increase reliability by identifying and analysing the aging process of SiC-MOSFET. In this paper, changes in electrical characteristics due to SiC-MOSFET aging and changes in loss and efficiency of the power conversion system are verified through experiments and simulations. A high electric field aging methodology are used to accelerate the SiC-MOSFET aging. Thereafter, a change in loss occurring during device aging are measured through a double pulse test, and this is modeled. By applying the loss modeling result to a bidirectional DC-DC converter, loss changes and efficiency changes due to converter aging are analyzed to determine the effect of the SiC-MOSFET aging on the converter.

Investigation of Fault-Mode Behaviors of Matrix Converters

곽상신 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.6

This paper presents a systematic investigation of the fault-mode behaviors of matrix converter systems. Knowledge about converter behaviors after fault occurrence is important from the standpoint of reliable system design, protection and fault-tolerant control. Converter behaviors have been, in detail, examined with both qualitative and quantitative approaches for key fault types, such as switch open-circuited faults and switch short-circuited faults. Investigating the fault-mode behaviors of matrix converters reveals that converter operation with switch short-circuited faults leads to overvoltage stresses as well as overcurrent stresses on other healthy switching components. On the other hand, switch open-circuited faults only result in overvoltage to other switching components. This study can be used to predict fault-mode converter behaviors and determine additional stresses on remaining power circuit components under fault-mode operations.

금속산업 노사관계 실태와 평가

곽상신 한국노동연구원 2016 노동리뷰 Vol.132 No.-

Matrix Converter

곽상신 전력전자학회 2020 전력전자학회지 Vol.25 No.4

노화 가속 실험 기반 전해 커패시터 잔여 유효 수명 예측 연구

곽상신,박혜진 대한전기학회 2022 전기학회논문지 Vol.71 No.11

In this paper, the Remaining Useful Life (RUL) of the electrolytic capacitor is estimated through the amount of change in capacitance and ESR. RUL is predicted by the conventional model and the amount of change in capacitance and ESR according to the operating time. This paper supplements the shortcomings of the conventional model that calculates the endpoint of life according to the operating conditions of the system. Therefore, the purpose of this text is to calculate the endpoint considering the aging state and speed of the capacitor. In order to confirm the degree of aging over time, the accelerated aging experiment of capacitors was conducted under two conditions of temperature and voltage charge/discharge stress. And capacitor state parameters, Capacitance and ESR, were measured. After predicting the endpoint through the conventional model, the error with the actual measured experimental value is predicted through data fitting. As a result, both types of aging showed high accuracy when data with a large degree of aging was used. In addition, the higher the tendency of the error between the calculated value of the conventional model and the actual value of the experiment, the higher the estimation accuracy. Therefore, in this paper, when applied to the algorithm proposed for voltage charging and discharging aging rather than temperature aging, it was confirmed that the estimation performance was superior to that of the conventional model estimation value.

고전계 스트레스상에서 Cascode-GaN-FET 소자의 노화 특성 연구

곽상신,김재창 대한전기학회 2022 전기학회논문지 Vol.71 No.11

This paper investigated changes in threshold voltage, on-resistance, turn-on delay, and turn-off delay of cascode GaN FETs under high electric field stress. As a result, the threshold voltage decreased, and the on-resistance increased under the stress of applying a positive high voltage. Also, the turn-on delay was reduced, and the turn-off delay increased. On the other hand, under the stress of applying a high negative voltage, the threshold voltage, on-resistance, and turn-on delay decreased, and the turn-off delay increased. These results imply that the conduction loss of the cascode GaN FET increases, and the dead time of the voltage source converter composed of the cascode GaN FET increases under positive high voltage stress. Also, the fact that the threshold voltage decreased under both positive and negative high voltage stress means that if the cascode GaN FET is subjected to high voltage stress, the reduced threshold voltage is more likely to turn on undesirably even at low gate voltages.

부하전류 추정기법에 의한 단상능동전력필터 제어

곽상신,이무영,최연호,임성운,권우현 전력전자학회 2000 전력전자학회 논문지 Vol.5 No.4

단상 능동전력필터에 있어서 비선형 부하전류를 직접 검출하지 않고 능통전력필터의 직류측 커패시터 전압을 이용해 추정하여 제어하는 방법을 제안한다. 이는 부하전류와 능동전택필터의 직류측 커패시터 전압을 봉사에 검출하는 기존의 방식에 비해 부하전류 검출단을 제거할 수 있음으로써 설치가 간편할 뿐만 아니라 가격을 낮출 수 있으면서도 동일한 성능의 능동전력필터의 구현을 가능하게 한다. 또한 직류측 커패시터 전압제어를 위해 샘플-흘드와 비례제어빙식을 사용하므로 기존의 저역통괴필터와 PI 제어시 적분기로 인한 지연을 없앨 수 있어 빠르고 우수한 과도응답특성을 나타낸다. 전원전압과 보상전류, 스위치 상태에 따라 8개의 모드로 나누어 능동전력필터의 동작을 설명하였으며, 제안한 방법의 성능을 실험을 통해 확인하였다. A new control method for a single-phase active power filter, based on a load current estimation using a DC capacitor voltage of active power filter without sensing nonlinear load current, is proposed in this paper. Because the method proposed can remove the load current sensor in comparison with a conventional method sensing the load current and DC capacitor voltage together, it can make the active power filter easy installation, low cost, small size with no performance detriment. In addition, sample-hold technique and proportional control method is adopted to control the DC capacitor voltage and as no delay element such as LPF or PI control in the conventional method is used, the transient response is fast and good. Operation of a single-phase active power filter which consist of eight mode is explained according to utility voltage, compensation current and switch state, and compensation characteristics of active power filter using proposed method is verified by experiment.