• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.151-152
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• 2018

본 논문에서는 병렬연결 인버터의 seamless mode transfer를 위한 제어기 설계를 수행하였다. 인버터의 경우 계통연계 모드에서는 전류원으로 동작하기 때문에 간접전류를 기반으로 제어를 실행하였고, 단독 운전에서는 인버터가 전압원으로 간주되기에 전압 제어가 필요하다. 또한 여러 대의 분산 발전원에 대해 동일 부하 분담을 위해 드룹제어를 이용하였다. 이러한 제어기들은 PR제어를 기반으로 하여 특정 주파수에 높은 이득을 가지게 하여 제어효율을 향상시켰다. 모드 변환 과정에 있어 전압의 변동을 최대한 줄이기 위한 제어 계획을 수립하였고, 이를 Psim 시뮬레이션으로 증명하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.21-31
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• 2017

In this paper, the Zynq system-on-chip (SoC) platform is used to design an adaptive noise reduction and edge-detection system using partial reconfiguration. Filters are implemented in a partially reconfigurable (PR) region to provide high computational complexity in real-time, 1080p video processing. In addition, partial reconfiguration enables better utilization of hardware resources in the embedded system from autonomous replacement of filters in the same PR region. The proposed edge-detection system performs adaptive noise reduction if the noise density level in the incoming video sequences exceeds a given threshold value. Results of implementation show that the proposed system improves the accuracy of edge-detection results (14~20 times in Pratt's Figure of Merit) through self-reconfiguration of filter bitstreams triggered by noise density level in the video sequences. In addition, the ZyCAP controller implemented in this paper enables about 2.1 times faster reconfiguration when compared to a PCAP controller.

• Journal of IKEEE
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• v.24 no.4
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• pp.1104-1108
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• 2020

This paper propose a variable proportional resonant feedforward algorithm for reducing the speed ripple of a three-phase permanent magnet synchronous motor. In general, the torque ripples can be generated by electrical pulsation due to current measurement errors and dead time and mechanical pulsation because of rotor eccentricity and eccentric load. These torque pulsations can cause speed pulsations of the motor and degrade the operating performance of the motor drive system. Therefore, in this paper, the factors of the speed ripple is analyzed and an algorithm to reduce the speed ripple is proposed. The proposed algorithm applied a variable proportional resonant controller in order to reduce the specific operating frequency included in the speed pulsation, and utilized a feedforward compensation controller structure to perform the compensation operation. The proposed algorithm is verified through various experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.567-575
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• 2016

This paper proposed the voltage control of stand-alone inverter for power quality improvement under unbalanced and non-linear load. The 3-phase DC-AC inverter controls CVCF(Constant Voltage Constant Frequency) and selective harmonic eliminate method in stand-alone mode by PR controller, and the stand-lone inverter supplies stable sinusoidal voltage to balanced, unbalanced and non-linear loads. The total harmonic distortion(THD) of line-to-line load voltage($V_{LL}$) is 1.2% in the balanced load. THD of $V_{LL}$ is reduced from 5.2% to 1.4% and 6.7% to 3.5%, respectively unbalanced and non-linear load. The stand-alone inverter can be supplies sinusoidal balanced voltage to unbalanced load because the voltage unbalanced factor(VUF) of $V_{LL}$ is reduced from 5.2% to 1.4% in the unbalanced load. Feasibility of control method for a stand-alone inverter will be verified through 30kW stand-alone inverter system.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.207-209
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• 2019

This paper proposes a grid-tied photovoltaic (PV) system, consisting of Voltage-fed dual-active-bridge (DAB) dc-dc converter with single phase inverter. The proposed converter allows a small dc-link capacitor, so that system reliability can be improved by replacing electrolytic capacitors with film capacitors. The double line frequency free maximum power point tracking (MPPT) is also realized in the proposed converter by using Ripple Correlation method. First of all, to eliminate the double line frequency ripple which influence the reduction of DC source capacitance, control is developed. Then, a designing of Current control in DQ frame is analyzed and to fulfill the international harmonics standards such as IEEE 519 and P1547, $3^{rd}$ harmonic in the grid is directly compensated by the feedforward terms generated by the PR controller with the grid current in stationary frame to achieve desire Total Harmonic Distortion (THD). 5-kW PV converter and inverter module with a small dc-link film capacitor was built in the laboratory with the proposed control and MPPT algorithm. Experimental results are given to validate the converter performance.

• Journal of environmental and Sanitary engineering
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• v.24 no.4
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• pp.112-115
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• 2009

This research was performed to purify water quality through removing T-N, and T-P and to estimating rate of $NO_x$ by the response of photocatalyst using ceramics. The ceramics was a mixtures of Titanium Diboride($TiB_2$) which is used to develop armored cars with excellent protective power and lightness, Olivine, and Hwangto with water and was furnaced for an hour at $1160^{\circ}C$. Hwangto and Olivine used in the study are produced at Haenam-gun, Jeonnam, and Andong-city, Gyeongsangbuk-do, respectively. The ground Hwangto and Olivine were seived through PR $100{\times}200$, and $TiB_2$ was a product of SIGMA ALDRICH. The experiment was performed under the sunlight, Mass flow controller was used for constant flow to pass through the pyrex reactor which was fully charged with furnaced ceramics. The concentration of $NO_2$ gas passed through the pyrex reactor was measured by Multi Gas Monitor. The reaction took for 60 minutes, The material was exposed to sunlight for 40 minutes. The sunlight was interrupted before and after the exposure for 10 minutes. The result showed that the concentration of $NO_2$ gas of the ceramics with $TiB_2$ and without $TiB_2$ became reduced and then maintained the same concentration under the sunlight, and became increased when the sunlight is interrupted. The $NO_2$ removing efficiency of the ceramics mixed with $TiB_2$ was 14~43% higher than that of the ceramics without $TiB_2$ under the sunlight. The study showed that the removing rate of $NO_2$ was 80% when the mixture rate of Hwangto, Olivine, and $TiB_2$ was 68%, 30% and 2%.