• JSTS:Journal of Semiconductor Technology and Science
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• 제14권6호
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• pp.802-809
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• 2014

This paper presents a dual-mode bias modulator (BM) for complementary metal oxide semiconductor (CMOS) power amplifiers (PAs). The BM includes a hybrid buck converter and a normal buck converter for an envelope tracking (ET) mode for high output power and for an average power tracking (APT) mode for low output power, respectively. The dual-mode BM and CMOS PA are designed using a $0.18-{\mu}m$ CMOS process for the 1.75 GHz band. For the 16-QAM LTE signal with a peak-to-average power ratio of 7.3 dB and a bandwidth of 5 MHz, the PA with the ET mode exhibited a poweradded efficiency (PAE) of 39.2%, an EVM of 4.8%, a gain of 19.0 dB, and an adjacent channel leakage power ratio of -30 dBc at an average output power of 22 dBm, while the stand-alone PA has a PAE of 8% lower at the same condition. The PA with APT mode has a PAE of 21.3%, which is an improvement of 13.4% from that of the stand-alone PA at an output power of 13 dBm.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.183.1-183.1
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• 2010

Recently, the increased interest in environmental issues has led to extensive research for development of green energy generation systems. However, only one type of generation system may not be sufficient for stand-alone mode because it cannot cope with the irregularity of weather condition. A hybrid generation system is able to make up for the weakness of each system. In this paper, a stand-alone hybrid wind/PV system is developed that can guarantee the stable energy supply. The system is suitable for power supply under 50W, and a vertical savonius type of blade was designed and applied for the wind generation system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1056-1057
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• 2015

A common DC bus is a useful connection for several DC output sources such as photovoltaic (PV), fuel cells, and batteries. Operation of the common DC power system with more than two DC output sources, especially in a stand-alone mode, requires a control scheme for the stable operation of the system. In this paper, a control scheme has been developed for applying DC power sources to the distribution system. The purpose of the control scheme is to make the best use of the DC power sources. The DC power system consists of PV, two energy storage systems and a DC-AC inverter with the control scheme. A distribution system was modeled in PSCAD/EMTDC. As the results, the control scheme is applied to the DC-AC inverter and the DC-DC converter for transfer operations between the grid-connected and the stand-alone mode to keep the DC bus and the AC voltage constant. The results from the simulation demonstrate the stable operation of a grid connected DC power system.

• 전력전자학회논문지
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• 제24권5호
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• pp.334-341
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• 2019

This study proposes the control strategy for the seamless mode transfer of indirect current controlled parallel grid-connected inverters. Under the abnormal grid condition, the grid-connected inverter can convert the operation mode from grid-connected to stand-alone mode to supply power to the local load. For a seamless mode transfer, the time delay problems caused by the accumulated control variable error must be solved, and the indirect current control method has been applied as one of the solutions. In this study, the design of control parameters for the proportional-resonant-based triple-loop indirect current controller and the control strategy for the seamless mode transfer of parallel grid-connected inverters are described and analyzed. The validity of the proposed mode transfer method is verified by the PSiM simulation results.

• Journal of Power Electronics
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• 제16권5호
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• pp.1869-1883
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• 2016

In recent years, some converter structures and analyzing methods for the voltage regulation of stand-alone self-excited induction generators (SEIGs) have been introduced. However, all of them are concerned with the three-phase voltage control of three-phase SEIGs or the single-phase voltage control of single-phase SEIGs for the operation of these machines under balanced load conditions. In this paper, each phase voltage is controlled separately through separated converters, which consist of a full-bridge diode rectifier and one-IGBT. For this purpose, the principle of the electronic load controllers supported by fuzzy logic is employed in the two-different proposed converter structures. While changing single phase consumer loads that are independent from each other, the output voltages of the generator are controlled independently by three-number of separated electronic load controllers (SELCs) in two different mode operations. The aim is to obtain a rated power from the SEIG via the switching of the dump loads to be the complement of consumer load variations. The transient and steady state behaviors of the whole system are investigated by simulation studies from the point of getting the design parameters, and experiments are carried out for validation of the results. The results illustrate that the proposed SELC system is capable of coping with independent consumer load variations to keep output voltage at a desired value for each phase. It is also available for unbalanced consumer load conditions. In addition, it is concluded that the proposed converter without a filter capacitor has less harmonics on the currents.

• 한국지능시스템학회논문지
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• 제21권1호
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• pp.29-35
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• 2011

본 논문에서는 신재생에너지원을 포함하는 독립형 마이크로그리드시스템의 멀티에이전트시스템 기반의 분산에너지관리시스템 설계를 위한 통합시뮬레이션 모델을 제안한다. 멀티에이전트기반 분산에너지관리시스템은 일반적인 중앙에너지관리시스템에 비해 여러 장점들을 가지고 있으나 각 상태에 따른 설계가 비교적 복잡하여 기존의 전력시스템 도구를 이용하여 분산 에너지관리시스템을 설계하기에는 많은 어려운 점들이 있었다. 또한 설계된 에너지관리시스템을 실제 시스템에 적용하여 평가하는 것은 비능률적이기 때문에 효과적인 에너지관시스템을 설계하기 위해서는 통합시뮬레이션 모델이 필요하다. 제안된 통합시뮬레이션 모델은 Matlab/Simpowersystem 기반의 마이크로그리드시스템의 시뮬레이션 모델과 이벤트기반의 알고리즘 설계에 많은 장점이 있는 Matlab/StateFlow을 이용하여 설계된 멀티에이전트기반의 분산에너지관리시스템으로 구성되었다. 통합시뮬레이션 모델의 효용성을 보이기 위하여 특정한 동작 조건들에서 제안된 모델의 출력들을 분석하였다.

• Journal of electromagnetic engineering and science
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• 제17권1호
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• pp.29-33
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• 2017

This paper proposes a half-mode substrate integrated waveguide (HMSIW) amplifier using lumped-element transition. The input and output impedances of this amplifier are matched by the lumped-element transition structure. This structure provides compact impedance and mode matching circuits between the HMSIW and a stand-alone amplifier. Surface mount technology inductors and capacitors are implemented to realize the lumped-element transition. A prototype of the proposed HMSIW amplifier shows 15 dB gain with 3 dB bandwidth of 4 to 7.05 GHz in a simulation and measurement.

• 한국항해항만학회지
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• 제35권9호
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• pp.749-753
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• 2011

A leisure ship has a stand-alone type power system, and a generator is in use on this condition. But the generator cannot be operated in condition of leisure activity, ocean measurement and etc, because of environment and noise. Recently, renewable energy system is connected with power system of the leisure-ship for saving energy. The renewable energy system can not supply the stable power to leisure-ship because power generation changes according to weather condition. And most of the leisure ship is operated without methodical power management system. This study's purpose is to develop SPMS(Smart Power Management System) algorithm using the renewable energy (photovoltaic, wind power and etc.). The proposed algorithm is able to supply stable the power according to operation mode. Furthermore, the SPMS manages electric load (sailing and communication equipment, TV, fan, etc.) and reduces operating times of the generator. In this paper, the proposed algorithm is realized and executed by using LabVIEW. As a result, the hour for operating the generator is minimized.

• 전력전자학회논문지
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• 제9권1호
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• pp.73-80
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• 2004

본 논문에서는 농형유도발전기를 이용한 독립형 풍력발전시스템의 최대전력 추종제어기법을 제안한다. 농형 유도발전기는 벡터제어 방식으로 동작되는데 d-축 전류에 의해 여자가 제어되고 q-측 전류에 토크가 제어된다. 이 토크제어에 의해 발전기는 풍속의 변화에 따라 최대전력을 발생하도록 가변속 제어된다. 발전된 전력은 ac/dc PWM 컨버터에 의해 직류 출력단 배터리뱅크로 충전된다. 제안된 기법은 M-G세트로 구성된 터빈시뮬레이터를 이용하여 실험적으로 검증된다.

• 대한전자공학회논문지
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• 제18권6호
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• pp.16-22
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• 1981

2716 PROM programmer for the latest 16 bit $\mu$-computer Mc68000 system, which can program the contents of object code to 2716 PROM or EPROM of 2K byte capability in stand alone mode, is designed and implemented.