• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.69-70
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• 2012

본 논문은 LCL 필터의 능동댐핑을 적용한 3상 4선식 PWM 정류기 제어 방법을 제안한다. 3상 4선식 PWM 정류기의 입력단에 위치한 LCL 필터는 단일 L 필터에 비해 필터 사이즈, 무게 감소와 입력 전류의 고조파 성분 감쇠 등에 장점을 가지고 있다. 그러나 LCL 필터의 공진 주파수의 영향으로 PWM 정류기 제어 안정성 문제를 가지고 있다. 이러한 문제를 해결하기 위해서는 LCL 필터에 능동댐핑을 적용하여 PWM 정류기 제어 안정성을 향상 시킨다. 시뮬레이션 결과를 통해 본 논문이 제안한 제어 방법의 실효성을 검증한다.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.215-216
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• 2018

본 논문에서는 Carrier-Based Pulse Width Modulation(CBPWM)을 사용한 Active Neutral Point Clamped (ANPC) 인버터의 안정적인 고장 허용 운전을 위한 중성점 전압 균형 제어 기법을 제안한다. 제안된 기법은 ANPC 인버터를 구성하고 있는 전력 반도체 스위치의 고장으로 인한 고장 허용 운전 시, 출력 특성이 저하되는 문제점을 해결하기 위해 스위칭 조합의 재구성과 기준 출력전압의 변조를 통한 중성점 전압 균형을 유지한다. 제안된 기법의 타당성은 RT-BOX를 통한 HIL 시뮬레이터를 이용하여 확인하였다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.142-144
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• 2020

본 논문은 액티브 클램프 포워드 컨버터(ACFC)에 적용 가능한 경부하 조건 효율 최적화 제어 기법을 제안한다. 기존의 액티브 클램프 포워드 컨버터는 경부하 조건에서 과도한 프리휠링 전류로 인해 큰 도통 손실이 발생하여 높은 효율을 기대하기가 어렵다. 제안하는 제어 방식은 복잡한 추가 회로 없이도 전도 손실을 줄이면서 경부하 효율을 유의미하게 개선할 수 있다. 제안하는 제어 방식의 실현 가능성 및 성능은 범용 AC 입력 및 65W 최대 출력에서 설계된 USB PD 어댑터 프로토타입 회로 구성을 통하여 실험 검증된다.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.65-76
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• 2024

With the recent activation of the offshore wind power industry, there has been a development of power plants with a scale exceeding 400MW, comparable to traditional thermal power plants. Renewable energy, characterized by intermittency depending on the energy source, is a prominent feature of modern renewable power generation facilities, which are structured based on controllable inverter technology. As the integration of renewable energy sources into the grid expands, the grid codes for power system connection are progressively becoming more defined, leading to active discussions and evaluations in this area. In this paper, we propose a method for selecting optimal reactive power compensation capacity when multiple offshore wind farms are integrated and connected through a shared interconnection facility to comply with grid codes. Based on the requirements of the grid code, we analyze the reactive power compensation and excessive stability of the 400MW wind power generation site under development in the southwest sea of Jeonbuk. This analysis involves constructing a generation site database using PSS/E (Power System Simulation for Engineering), incorporating turbine layouts and cable data. The study calculates reactive power due to charging current in internal and external network cables and determines the reactive power compensation capacity at the interconnection point. Additionally, static and dynamic stability assessments are conducted by integrating with the power system database.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.12
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• pp.1222-1228
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• 2008

A small satellite, DubaiSat-1 FM(Flight Model), which is based on SI-200 standard bus platform and scheduled to be launched in 2008, is being developed by Satrec Initiative and EIAST(Emirates Institution for Advanced Science and Technology). The TCS(Thermal Control Subsystem) of DubaiSat-1 FM has been designed to mainly utilize passive thermal control in order to minimize power consumption, but the active control method using heaters has been applied to some critical parts. Also, thermal analysis has been performed for DubaiSat-1's mission orbit using a thermal analysis model. The thermal design is modified and optimized to satisfy the design temperature requirements for all parts according to the analysis result. The thermal control performance of DubaiSat-1 FM is verified by thermal vacuum space simulation, consisting of thermal cycling and thermal balance test. Also, to validate the thermal modeling of DubaiSat-1 FM, comparison of test results with analysis has been performed and model calibration has been completed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.4
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• pp.8-15
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• 2000

In this paper, we realize the active PFC(Power Factor Correction) system of BF(Boost Forward) converter with PWM-PFM(Pulse Width Modulation-Pulse Frequency Modulation) control technique to control DC output voltage, to remove the noise like harmonics at output voltage, and to control the input current with sinusoidal wave synchronized by the source voltage.To achieve the desired load voltage and improved PFC, we first implement current shaping control at the inverting stage and make the converted output DC voltage with forward converter. After making the ratio of output voltage to current as 50V/1A and the duty ratio greater than 0.5. When input voltage is 30V and boost inductance is 1.1mH. we control the voltage changing rate according to the variation of load resistance using a PWM-PFM control technique. And finally we prove experimentally, we attenuated its harmonics and improved PF up to 0.96 using the current shaping technique.

• Journal of IKEEE
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• v.20 no.1
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• pp.45-53
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• 2016

This paper presents a CMOS interface circuit for vibration energy harvesting with MPPT (Maximum Power Point Tracking). In the proposed system a PMU (Power Management Unit) is employed at the output of a DC-DC boost converter to provide a regulated output with low-cost and simple architecture. In addition an MPPT controller using FOC (Fractional Open Circuit) technique is designed to harvest maximum power from vibration devices and increase efficiency of overall system. The AC signal from vibration devices is converted into a DC signal by an AC-DC converter, and then boosted through the DC-DC boost converter. The boosted signal is converted into a duty-cycled and regulated signal and delivered to loads by the PMU. A full-wave rectifier using active diodes is used as the AC-DC converter for high efficiency, and a DC-DC boost converter architecture using a schottky diode is employed for a simple control circuitry. The proposed circuit has been designed in a 0.35um CMOS process, and the designed chip occupies $915{\mu}m{\times}895{\mu}m$. Simulation results shows that the maximum power efficiency of the entire system is 83.4%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.678-684
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• 2013

This paper describes a low-power baseband circuit for SAW-less LTE-Advanced transmitters. The proposed transmitter baseband circuit consists of a 2nd-order Tow-Thomas type active RC-LPF and a 1st-order passive RC LPF. It can provide a 7 multi-channel cut-off frequencies and wide gain control range of -41 dB ~ 0 dB with a 1-dB step. The proposed 2nd-order active RC-LPF adopts an op-amp in which three other sub-op amps are in parallel connected to reduce DC current for different cutoff frequency. In addition, each sub-op amp adopts both Miller and feed-forward phase compensation method to achieve an UGBW of more than 1-GHz with a small DC power consumption. The proposed baseband circuit is implemented in 65-nm CMOS technology, consuming DC power from 6.3 mW to 24.1 mW from a 1.2V supply voltage for each different cut-off frequency.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.2
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• pp.179-184
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• 2016

The electrical load testing system developed from this study was designed to control rated-capacity-testing or variable-load-testing in an active and precise manner and save electric energy during testing, and also to convert the saved electric energy through the electrical load testing system to grid line. As for the device under testing, it was designed to be applied to not only transformer, rectifier, voltage regulator, inverter which require grid voltage source but, also applied to electric power, aerogenerator, photovoltaic, hybrid generator, battery, etc. which do not require grid voltage source. The system was designed to return the power consumed during the testing to the grid line by connecting the synchronizing pwm inverter circuit to the grid voltage source, and was also made to enable the being-tested system from disuse of approximately 93.4% energy when compared to the conventional load testing system which has used the passive resistor.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.6
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• pp.584-591
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• 2000

Power Quality Compensator(PQC) has been installed to protect the sensitive loads against the voltage disturbances, such as voltage sag and interruption. In general, static switch is used for the purpose of link between utility and PQC. So transfer operation of the static switch play a important part in the PQC. Many studies on the structure and control of PQC have been progressed in active, but these researches have been rarely mentioned about any voltage-disturbances-detection method to start the PQC operation. In this paper, a new voltage-disturbances-detection algorithm for computer application loads using the CBEMA/ITIC curve is proposed for transfer operation of the static switch. The proposed detection algorithm is implemented to get fast detecting time through the comparison of instantaneous 3-phase voltage values transferred to DC values in the synchronous reference frame with the operating reference values. To get the robust characteristics against the noise, a first order digital filter is designed. The magnitude falling and phase delay caused by the filter are compensated through the error normalizing and numerical analysis using transfer function, respectively. Finally, the validity of the proposed algorithm is proved by ACSL simulation and experimental results.