• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.74-81
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• 2006

This paper proposes the sensorless vector control scheme of a Non-salient permanent-magnet synchronous motor (SPMSM) using programmable low pass filter (PLPF) to estimate a stator flux with the information of a rotor position and speed. The sesorless vector control of PMSM using PLPF can solves the dc drift problem associated with a pure integrator and a LPF. Also, the PLPF has the phase and gain compensator to estimate exactly rotor position and speed. Therefore, the information of a position and speed is exactly estimated because the drift and offset problems are solved by the PLPF. The experimental results show good performance over the 10[%] of the rated speed and under load condition.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.100-106
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• 2006

This paper proposes a full fuzzy-logic-based vector control for a permanent-magnet synchronous motor (PMSM). The high-performance of the proposed fuzzy logic control (FLC)-based PMSM drive are investigated and compared with the conventional proportional-integral (PI) controller at different conditions, such as step change in command speed and load and etc. In the experimental and simulation the FLC is employed in the speed and current controller. The experimental results show to be a suitable replacement of the conventional PI controller for the high-performance drive system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.29-37
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• 2006

High speed electric trains have nonlinear loads including converters and inverters for the control synchronous motors. Harmonics produced by these devices are large, but also have noticeable time varying characteristics. Since the large loads are supplied from the power system grid, it must be recognized that not only will the system of utility be impacted, but neighboring customer system could be impacted as well. In this paper time-varying harmonics for high speed electric train loads are measured and evaluated by international harmonic standards IEEE Std. 519 and IEC 61000-3-6 using a cumulative probablistic approach.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.92-99
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• 2006

The swirl ratio of a charge in the cylinder was estimated by calculating the ratio of the rotary speed of charge which could be simulated from the rotary speed of paddle in the swirl measurement apparatus, to the engine speed which could be calculated by measuring intake air flow rate. The automation of the swirl ratio measurement for cylinder head was achieved by controling both valve lift in cylinder head and a suction pressure of surge tank using two step-motors. The number of measurement position for calculating mean swirl ratio was varied by adjusting the interval of valve lift. The mean swirl ratio with varying the number of measurement position showed nearly constant value. Two measurement methods for measuring the swirl ratio were compared, one was to control the suction pressure of the surge tank with PID (proportional, integral, differential) mode with by-pass valve controlled by the step motor and the other did not control the surge tank pressure by fixing the by-pass valve. The difference of the mean swirl ratio between the two measurement methods showed nearly constant value with varying the number of measurement position. This means that the w/o PID control method could be preferred to the PID control method which has been used, due to the simpleness of the swirl measurement.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.4
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• pp.439-446
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• 2016

An in-wheel motor vehicle is a type of car that is equipped with an electric motor for each wheel. It is possible to acquire vehicle stability through a seperate driving torque control per wheel, since it directly generates the driving torque via the wheel motors. However, the vehicle ride comfort and road holding performance worsen depending on the increase of the wheel weights. In order to compensate for the impaired performance, an integrated chassis control system of the rear in-wheel motor vehicle is proposed. The proposed integrated chassis control system is composed of a driving torque control system, a semi-active suspension system, and an ESC system. According to the vehicle dynamic simulation of an in-wheel motor vehicle equipped with the integrated chassis control system, it is found that the system can improve the driving stability, ride comfort, and driving efficiency of the in-wheel motor vehicle.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.3
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• pp.52-56
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• 2011

Active regeneration in CDPF requires $O_2$ which regenerates soot at high temperature. However, small amount of NO can interrupt $O_2$ regeneration in CDPF. To verify this phenomena, soot oxidation experiments using a flow reactor with a $Pr/CeO_2$ catalyst are carried out to simulate Catalyzed Diesel Particulate Filter (CDPF) phenomena. Catalytic soot oxidation with and without small amount of NO is conducted under tight contact condition. As the heating rate rises, the temperature gap of maximum reaction rate is increased between with and without 50ppm NO. To accelerate the $NO_2$ de-coupling effect, CTO process is performed to eliminate interfacial contact for that time. As CTO process is extended, temperature which indicates peak reaction rate increases. From this result, it is found that small amount of NO can affect tight contact soot oxidation by removal of interfacial contact between soot and catalyst.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.8-14
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• 2008

For nondestructive inspection of electron beam (EB) welding part in automotive power transmission assembly, a pulse-echo ultrasonic testing apparatus in water immersion has been applied using the ultrasonic waves with a frequency of 10MHz. However various problems have appeared during the ultrasonic inspection, which led to some significant mistakes in automatic quality evaluation of the welding parts. Experimental study showed that the state of water couplant medium containing some amount of contaminants, rusts and anti-corrosion agents had considerable influences on the reduction of ultrasonic amplitudes during wave propagation. The amplitude reduction depending on the coupling medium state could bring about some mis-diagnoses for defects in the welding parts. The results proposed that for a reliable inspection of defects in welds the state of water medium should be kept in about 15 volume fractions (vol.%) of anti-corrosion agents and in minimized contaminants.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.130-135
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• 2004

This paper describes the development of the dual-thrust rocket motor, which gets a significant change in thrust level by varying the burning area of the propellant grain. Reduced smoke propellant of low burning rate was formulated and the finocyl type grain was designed to get the boosting- and sustaining-phase of the thrust level. And the motor firing data were analyzed in detail. Developed motor was applied to the missile system to implement the successful flight test and this development helped to upgrade the performance of the missile system. The results will be usefully applied to the development of the similar rocket motors.

• Journal of Sensor Science and Technology
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• v.24 no.3
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• pp.175-180
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• 2015

Worldwide, studies on intelligent vehicles for the convenience of drivers have been actively conducted as the number of cars has increased. However, vehicle convenience enabled by buttons lowers the concentration on driving and hence poses as a huge threat to the safety of the driver. The use of one of the convenient features, impaired driving auxiliary equipment, is limited because of its complex usage, and this device also hinders the front view of the driver. This paper proposes a vehicle-control device for controlling the convenient features as well as changes in speed and direction using gestures and motions of the driver. This device consists of an ultrasonic sensor for recognizing movement, an arduino for accepting signal control functions and servo and DC motors apply to various vehicle parts. Firstly, the vehicle-control device was designed using a 3D CAD program known as Solid-works based on the size of the steering wheel. Then, through simulations, a suitable length for minimizing the absorbent between ultrasonic sensors was confirmed using a program known as COMSOL Multiphysics. Finally, simulation results were verified through experiments, and the optimal size of the device was identified through the number of errors.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.4
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• pp.207-215
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• 2015

Since the oil shock of 1970's there was a strong upward tendency for the use of the high viscosity and poorer quality fuels. Therefore the misfiring engine occurs due to the decrease of quantity injected for lean burn and emission control in CI diesel engine. In this study, it is designed and used the test bed which is installed with turbocharger and intercooler. In addition to equipped using CRDI by controlling injection timing with mapping modulator, it has been tested and analyzed the engine performance, combustion characteristics, and emission as operating parameters.