• Journal of Power Electronics
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• 제15권4호
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• pp.899-909
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• 2015

A dual-input boost-buck converter with coupled inductors (DIBBC-CI) is proposed as a thermoelectric generator (TEG) power conditioner with a wide input voltage range. The DIBBC-CI is built by cascading two boost cells and a buck cell with shared inverse coupled filter inductors. Low current ripple on both sides of the TEG and the battery are achieved. Reduced size and power losses of the filter inductors are benefited from the DC magnetic flux cancellation in the inductor core, leading to high efficiency and high power density. The operational principle, impact of coupled inductors, and design considerations for the proposed converter are analyzed in detail. Distributed maximum power point tracking, battery charging, and output control are implemented using a competitive logic to ensure seamless switching among operational modes. Both the simulation and experimental results verify the feasibility of the proposed topology and control.

• 한국정보통신학회논문지
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• 제15권10호
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• pp.2072-2078
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• 2011

태양광을 이용한 태양광 발전시스템은 태양을 정면으로 바라 볼 때 가장 큰 효율을 얻을 수 있다. 즉, 태양의 위치에 대한 집광판(PV; Photovoltic)의 법선벡터를 일치시켜야 가장 높은 효율을 얻게 된다. 본 논문에서는 시간의 변화에 따라 태양의 이동경로를 추적할 수 있도록 태양의 그림자를 판독할 수 있는 8개의 CdS 센서 모듈을 통하여 태양의 위치를 판독하여 태양의 위치를 추적할 수 있는 시스템을 제시하고자 한다. 태양광 추적시스템의 퍼지제어기(fuzzy controller)는 퍼지 입력공간에 대한 격자형 퍼지분할(grid-type fuzzy partition) 영역으로 분할한 후 퍼지규칙(fuzzy rule)을 수립하여 시스템을 제어하도록 설계하였다. 본 논문에서는 태양광 추적을 위한 간단한 모형의 2축 제어시스템을 구성하였으며, CdS 모듈의 좌표축과 집광판의 좌표축을 일치시키도록 구성하였다. 이러한 시스템은 고정된 장소 및 선박과 같은 이동하는 환경에 효과적으로 태양광을 추적할 수 있는 지능형 퍼지제어기의 적용가능 성을 제시하고자 한다.

• 한국운동역학회지
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• 제17권1호
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• pp.81-90
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• 2007

The effort identifying positioning information of the moving object in real time has been a issue not only in sport biomechanics but also other academic areas. In order to solve this issue, this study tried to track the movement of a pitched ball that might provide an easier prediction because of a clear focus and simple movement of the object. Machine learning has been leading the research of extracting information from continuous images such as object tracking. Though the rule-based methods in artificial intelligence prevailed for decades, it has evolved into the methods of statistical approach that finds the maximum a posterior location in the image. The development of machine learning, accompanied by the development of recording technology and computational power of computer, made it possible to extract the trajectory of pitched baseball from recorded images. We present a method of baseball tracking, based on object tracking methods in machine learning. We introduce three state-of-the-art researches regarding the object tracking and show how we can combine these researches to yield a novel engine that finds trajectory from continuous pitching images. The first research is about mean shift method which finds the mode of a supposed continuous distribution from a set of data. The second research is about the research that explains how we can find the mode and object region effectively when we are given the previous image's location of object and the region. The third is about the research of representing data into features that we can deal with. From those features, we can establish a distribution to generate a set of data for mean shift. In this paper, we combine three works to track baseball's location in the continuous image frames. From the information of locations from two sets of images, we can reconstruct the real 3-D trajectory of pitched ball. We show how this works in real pitching images.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.93-94
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• 2010

This paper proposes maximum power point tracking(MPPT) control algorithm of PV system using a novel method. The proposed hybrid method is composed perturb and observe (PO) method and constant voltage(CV) method. PO method is simple to realize and CV method is possible to tracking MPP with low insolation. Response characteristics of proposed algorithm is compared to conventional PO method with insolation variation. This paper proves the validity of proposed algorithm through the analysis result.

• 한국전자통신학회논문지
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• 제6권6호
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• pp.855-864
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• 2011

본 논문은 IPMSM(Interior Permanent Magnet Synchronous Motor)의 고성능 운전을 위해 비선형 제어를 기반으로 하는 적응 백스텝핑 제어기를 제안한다. 먼저 각속도의 추종성능을 향상시키기 위해서 비선형 백스텝핑 제어기를 설계한다. 파라메타 변동의 영향을 고려하지 않고 설계된 제어기는 고성능 운전이 어렵다. 부하토크의 변동에 대해 실시간 적응할 수 있는 파라메타 추정기를 설계에 포함하여 고성능 운전이 가능하게 한다. 또한 전동기의 효율적인 전력소비를 위하여 최대토크를 얻기 위한 최소전류의 운전을 할 수 있도록 제어기를 설계하였다. 제안된 제어기로 2마력급의 IPMSM에 적용하여 각속도 레퍼런스에 대한 추종성능과 부하토크 변동에 대한 추정, 그리고 MTPA(Maximum Torque per Ampere) 운전을 시험하여 일정토크 운전영역에서 안정화된 강건한 제어기임을 시뮬레이션을 통해 확인할 수 있었다.

• 전기전자학회논문지
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• 제26권2호
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• pp.211-218
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• 2022

본 논문에서는 저궤도 위성 원격측정데이터 신호 수신을 위한 S-대역 위상배열안테나를 제안하였다. 제안된 안테나는 16개의 부배열 조립체, 16개의 능동회로모듈, 수직 급전회로망 및 제어/전원반으로 구성되며 고각 방향으로 빔틸트가 수행된다. 개발된 안테나는 고각 축과 위성 궤적을 일치시키고 개구 중심을 위성 궤적 상의 최대 고각을 바라보도록 하여 정밀한 위성 추적을 수행하였다. 저궤도 위성의 궤적은 위성점 계산을 통하여 정확하게 산출하였다. 위성 추적 시험은 최대 고각을 기준으로 ±30° 범위에서 수행되였다. 위성 추적 시험 결과 최대 고각에서의 S/N비는 16.5 dB이고 Eb/No는 13.3 dB를 얻었다. 수행된 위성 추적 결과는 사전 시스템 분석 결과와 잘 일치함을 확인하였다.

• 전력전자학회논문지
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• 제21권3호
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• pp.238-248
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• 2016

In this study, an automatic command mode transition strategy of direct power control (DPC) is proposed for permanent magnet synchronous generators (PMSGs) medium-voltage (MV) offshore wind turbines (WTs). Benchmarking against the control methods are performed based on a three-level neutral-point-clamped (NPC) back-to-back type voltage source converter (VSC). The ramping rate criterion of complex power is utilized to select the switching vector in DPC for a three-level NPC converter. With a grid command and an MPPT mode transition strategy, the proposed control method automatically controls the generated output power to satisfy a grid requirement from the hierarchical wind farm controller. The automatic command mode transition strategy of DPC is confirmed through PLECS simulations based on Matlab. The simulation result of the automatic mode transition strategy shows that the proposed control method of VOC and DPC achieves a much shorter transient time of generated output power than the conventional control methods of MPPT and VOC under a step response. The proposed control method helps provide a good dynamic performance for PMSGs MV offshore WTs, thereby generating high quality output power.

• 전기학회논문지
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• 제65권4호
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• pp.533-538
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• 2016

In a power grid that has a high penetration of wind power, the highly-fluctuating output power of wind turbine generators (WTGs) adversely impacts the power quality in terms of the system frequency. This paper proposes a power smoothing scheme of a variable-speed WTG that can smooth its fluctuating output power caused by varying wind speeds, thereby improving system frequency regulation. To achieve this, an additional loop relying on the frequency deviation that operates in association with the maximum power point tracking control loop, is proposed; its control gain is modified with the rotor speed. For a low rotor speed, to ensure the stable operation of a WTG, the gain is set to be proportional to the square of the rotor speed. For a high rotor speed, to improve the power smoothing capability, the control gain is set to be proportional to the cube of the rotor speed. The performance of the proposed scheme is investigated under varying wind speeds for the IEEE 14-bus system using an EMTP-RV simulator. The simulation results indicate that the proposed scheme can mitigate the output power fluctuation of WTGs caused by varying wind speeds by adjusting the control gain depending on the rotor speed, thereby supporting system frequency regulation.

• Journal of Power Electronics
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• 제13권4호
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• pp.558-568
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• 2013

In this paper, a new decoupling technique for a flyback inverter using an active power decoupling circuit with auxiliary winding and a novel switching pattern is proposed. The conventional passive power decoupling method is applied to control Maximum Power Point Tracking (MPPT) efficiently by attenuating double frequency power pulsation on the photovoltaic (PV) side. In this case, decoupling capacitor for a flyback inverter is essentially required large electrolytic capacitor of milli-farads. However using the electrolytic capacitor have problems of bulky size and short life-span. Because this electrolytic capacitor is strongly concerned with the life-span of an AC module system, an active power decoupling circuit to minimize input capacitance is needed. In the proposed topology, auxiliary winding defined as a Ripple port will partially cover difference between a PV power and an AC Power. Since input capacitor and auxiliary capacitor is reduced by Ripple port, it can be replaced by a film capacitor. To perform the operation of charging/discharging decoupling capacitor $C_x$, a novel switching sequence is also proposed. The proposed topology is verified by design analysis, simulation and experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.55-57
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• 2007

A Power control and Distribution Unit (PCDU) plays roles of protection of battery against overcharge by active control of solar array generated power, distribution of unregulated electrical power via controlled outlets to bus and instrument units, distribution of regulated electrical power to selected bus and instrument units, and provision of status monitoring and telecommand interface allowing the system and ground operate the power system, evaluate its performance and initiate appropriate countermeasures in case of abnormal conditions. In this work, we perform the preliminary design of a PCDU for the small Low Earth Orbit (LEO) Satellite applications. The main constitutes of the PCDU are the battery interface module, solar array regulators with maximum power point tracking (MPPT) technology, heater power distribution modules, internal converter modules for regulated bus voltage generation, power distribution modules of unregulated and regulated primary bus, and instrument power distribution modules.