• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.380-384
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• 2010

A micromirror for a laser display system actuated by the electromagnetic force induced by the surface coil and the permanent magnet was designed and analyzed through the coupled physics analyses incorporating the electromagnetics, mechanics, and electrothermal analysis because the mechanical rotation of the micromirror is driven by the electromagnetic driving force. The proposed micromirror has two torsion beams to sustain the mirror plate which has surface coils on the top and the two permanent magnets exists on both sides of the micromirror for an external magnetic field source. The designed micromirror has the resonant frequency of 3.82kHz. When the magnetic field of the permanent magnet is 0.4T, the coil has 4 turns, and the current density of coil is 3.6A/$mm^2$, the estimated z axis displacement of the mirror plate edge is 0.23mm which corresponds to the rotation angle of $14.2^{\circ}$. When considering the joule heating in the current-carrying coil, the maximum temperature of the mirror plate is obtained as 300.045K, which induces the negligible changes in the rotation angle and the resistance of the coil.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1253-1255
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• 2003

Since the residential load is an AC load and the output of solar cell is a DC Power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation. it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper DC/AC converter is three phase PWM converter with smoothing reactor. And then, feedforward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.443-445
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• 1995

Since the residential load is an AC load, while the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell and must provide the sinusoidal wave current and voltage with unity power factor in the case of driving to Interact with utility line. It is always necessary for the output of solar cell to operate in the vicinity of maximum power point, since it is greatly fluctuated by insolation. This paper treats that we will constitute a single phase PWM voltage source inverter and trace the modulation index which always maximize the output of solar cell in propotion to insolation variation and prove it by simulation that we can provide current wave, which is nearly sinusoidal wave with unity power factor, for load and utility line.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.143-148
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• 2023

Among the characteristics of SRM, due to nonlinearity, it is difficult to properly operate to form maximum torque and minimum torque pulsation. In addition, in the case of fixed switching angle control, torque formation according to speed variation is unstable, thereby reducing efficiency. Therefore, active switching angle control according to speed variation is required. Therefore, active switching angle control according to speed variation is required. In this paper, a method for improving driving performance by reducing torque ripple by automatic control of the advance angle and increasing output torque was sought from the problem caused by the nonlinearity of the SRM. In addition, the optimal operation of SRM due to the switching variable according to the performance of the hysteretic current controller was examined.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.6
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• pp.855-864
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• 2011

In this paper, a nonlinear controller based on adaptive back-stepping method is proposed for high performance operation of IPMSM(Interior Permanent Magnet Synchronous Motor). First, in order to improve the performance of speed tracking a nonlinear back-stepping controller is designed. Since it is difficult to control the high performance driving without considering parameter variation, a parameter estimator is included to adapt to the variation of load torque in real time. In addition, for the efficiency of power consumption of the motor, controller is designed to operate motor with minimum current for maximum torque. The proposed controller is applied through simulation to the a 2-hp IPMSM for the angular velocity reference tracking performance and load torque volatility estimation, and to test the MTPA(Maximum Torque per Ampere) operation in constant torque operation region. The result verifies the efficacy of the proposed controller.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.9
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• pp.873-882
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• 2013

The effective way of estimation and analysis of EMI(Electromagnetic Interference) in Wireless Power Transfer System operating at 13.56 MHz is proposed. In this paper methodology of driving magnetic field strength and electric loop current of two antennas which are in free space and on PEC plane using image theory and duality is proposed. Perfect electric conductor(PEC) is planar, infinite in extent, and perfectly conducting plane. And we will refer it as PEC plane. A equivalent circuit model is used to analyze. Using this theoretical analysis, we can derive maximum magnetic field strength of the far-field region numerically using measured data of near-field maximum magnetic field strength. The experimental results using commercial numerical simulation tool are in agreement with the theoretical results. Also, using the derivation of maximum magnetic field strength in the far-field region, we can easily estimate the maximum allowable power dissipation that meets EMI regulations.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.867-874
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• 2021

The IoT (Internet of Things) technology is rapidly becoming an important consideration in many engineering fields in the current 4th industrial era. In recent years, the concepts of digital shipbuilding and smart factories have been adopted as trends in shipyards. However, there is active interest in research on implementing autonomous driving in autonomous vehicles and airplanes, which is currently available in commercial form in a limited capacity. The present study is regarding the path-tracking performance of a boat to accomplish an autonomous driving mission using a flight controller (FC) and real-time kinematic (RTK) global positioning system (GPS) based on an open-source Ardupilot; an actual sea test is also performed using this system on a calm lake. The boat's mission is to evaluate the maneuverability of the self-driving process to a specific point and returning to the home position. For a given speed, the difference between the preset mission trajectory and actual operational trajectory was analyzed, and a series of studies were conducted on the applicability of the system to ships. In addition, the movements and maneuverability of the OmniX-type hull with four propellers were investigated, and the driving path-tracking performance was observed to increase by a maximum of 48%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1734-1740
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• 2012

In this paper, we propose a FSOURCE circuit which requires such a small switching current that an eFuse OTP memory can be programmed in the post-package state of the PMIC chips using a single power supply. The proposed FSOURCE circuit removes its short-circuit current by using a non-overlapped clock and reduces its maximum current by reducing the turned-on slope of its driving transistor. Also, we propose a DOUT buffer circuit initializing the output data of the eFuse OTP memory with arbitrary data during the power-on reset mode. We design a 24-bit differential paired eFuse OTP memory which uses Magnachip's $0.35{\mu}m$ BCD process, and the layout size is $381.575{\mu}m{\times}354.375{\mu}m$($=0.135mm^2$).

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.385-391
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• 2023

As the use of electric vehicles has increased to minimize carbon emissions, the analyzing the state and performance of lithium-ion batteries that is instrumental in electric vehicles have been important. Comprehensive analysis using not only the voltage, current and temperature of the battery pack, which can affect the condition and performance of the battery, but also the driving data and charging pattern data of the electric vehicle is required. Therefore, a thorough analysis is imperative, utilizing electric vehicle operation data, charging pattern data, as well as battery pack voltage, current, and temperature data, which collectively influence the condition and performance of the battery. Therefore, collection and preprocessing of battery data collected from electric vehicles, collection and preprocessing of data on driver driving habits in addition to simple battery data, detailed design and modification of artificial intelligence algorithm based on the analyzed influencing factors, and A battery analysis and evaluation model was designed. In this paper, we gathered operational data and battery data from real-time electric buses. These data sets were then utilized to train a Random Forest algorithm. Furthermore, a comprehensive assessment of battery status, operation, and charging patterns was conducted using the explainable Artificial Intelligence (XAI) algorithm. The study identified crucial influencing factors on battery status, including rapid acceleration, rapid deceleration, sudden stops in driving patterns, the number of drives per day in the charging and discharging pattern, daily accumulated Depth of Discharge (DOD), cell voltage differences during discharge, maximum cell temperature, and minimum cell temperature. These factors were confirmed to significantly impact the battery condition. Based on the identified influencing factors, a battery analysis and evaluation model was designed and assessed using the Random Forest algorithm. The results contribute to the understanding of battery health and lay the foundation for effective battery management in electric vehicles.

• Journal of ILASS-Korea
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• v.22 no.3
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• pp.122-128
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• 2017

Currently, the proportion of diesel vehicles in all automobile has grown significantly over the past few years. Air pollutant also grew up and became a social problem. In particular, the issue of NOx emissions caused by NOx high emission in real driving has become a global issue. Despite the fact that the regulatory and reduction project of the new vehicle is actively carried out, there are no existence regulations of In-use diesel vehicle's NOx emission. Therefore, the emission characteristics of the in-use diesel vehicles were investigated to seek ways to reduce NOx emissions in this study. The test targets were used in 237 close inspection of exhaust gases and model year varied from 1996 to 2011. However, the classification of emissions by emission standards differed considerably from NOx emissions. This means that the selection method for early retirement targets should be converted from model year to amount of emissions. If the current early retirement program was applied to the existing system, pre-Euro 3 was 22.530 g/km and Euro 4 was 21.810 g/km to NOx reduction. However, when the vehicle was changed to high emission target vehicle, NOx reduction increase maximum 84.705 kg/yr. According to the study results, an effective reduction in NOx emissions can be achieved if an earlier target in expanded to Euro 4 vehicles.