• 한국데이터정보과학회:학술대회논문집
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• 2002.06a
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• pp.141-149
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• 2002

In this paper, we propose EWMA control charts using the life time data for the system with the constant failure rate, which were drawn from the fixed sampling interval without replacement (with replacement), and investigate the power of detection of EWMA by comparing ARL of EWMA control charts with one of Shewhart control charts.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.9
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• pp.1325-1333
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• 2017

The sensorless control of blushless DC motor(BLDCM) is based on the $120^{\circ}$ control in which the back electromotive force(Back EMF) for estimating the position of the rotor can be detected. However, the $120^{\circ}$ control has a disadvantage that the torque constant is small as compared with $180^{\circ}$ control which can not detect the back EMF. The $150^{\circ}$ control which complements these problems makes it possible to detect the back EMF and improve the torque constant by 12.5% compared to the $120^{\circ}$ control. Therefore, this paper compares the output characteristics of BLDCM through finite element method analysis (FEA) by the conventional and proposed control methods of BLDCM for water circulation system and proposes design for downsizing and weight reduction of BLDCM according to secured torque constant. The validity of the proposed control and design proposal is proved through simulation and experimental results by comparing the output characteristics of $120^{\circ}$ control and $150^{\circ}$ control.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.6
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• pp.395-402
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• 2000

This paper presents the improvement for speed characteristics of a Brushless DC Motor (BLDCM), it was applied to digital PI control for this. The practical PID control has been widely used to velocity control of DC motors. In this paper, a digital PI controller is used in order to decrease the speed error in constant velocity control of BLDCM. A TMS320C31 DSP is used for the microprocessor of digital PI control. The method using the DSP carry out the real-time control. The DSP has the rapid calculation ability and sampling time used lms. Driving BLDCM used 50W, motor input DC 150V and rotation speed 3000rpm. When BLDCM is to approval for discretion velocity at the acceleration and deceleration driving with any load, it was a feasible for stabilization control. Therefore, the experimental results indicate the superiority and validity of the velocity control by digital PI control.

• Journal of Power Electronics
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• v.10 no.1
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• pp.1-8
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• 2010

A new scheme for sliding-mode control (SMC) of DC-DC converters with a constant switching frequency is proposed. The scheme is based on the averaging model and the output signal of the controller is $d^+$ or $d^-$ instead of the on or off signal of a direct sliding-mode (SM) controller or the continuous signal d = $u_{eq}$ of an indirect SM controller. Two approaches using the new scheme are also proposed and the design procedures for a buck converter are given in detail. The first approach called constant $d^+$ and $d^-$ SMC is simple, cost effective and dynamically fast. In order to improve the dynamic characteristics of the reaching phase and to alleviate chattering, the second approach called reaching law SMC is also presented. Analyses and simulation results demonstrate the feasibility of the proposed scheme.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.5
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• pp.585-591
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• 1998

It is proposed a new compensation method in the rotor time constant of indirect vector controlled induction motor. The proposed scheme is an on-line method using the stator current error that is the difference between current command and estimated current calculated from terminal voltages and currents. As the current error becomes to zero, the rotor time constant in the vector controller approaches the real value. The proposed method shows good performances in the transient region as well as in the steady state region regardless of load torque variation, and it is verified by the computer simulation using SIMULINK in Matlab.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.4
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• pp.173-178
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• 2007

As development of industry is accelerated, most electricity load system requires power supply that could be high precision and effective control. Among supply and control unit of suitable power supply in these load characteristic, inverter systems of constant current regulate is used widely control of lighting & beaconing of aerodromes and electric heating system. Therefore, in this paper proposed a inverter systems of constant current regulate that using improved measurement and switching techniques. Proposed measure techniques that used moving average method of instantaneous r.m.s. for measuring current sensing improved response and precision. Also, in this paper proposed improved high effectiveness switching techniques that get high efficiency of inverter by the double-carrier modulation. Results of an experiment proved effect of proposed system.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.326-328
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• 1994

A modified Kohonen's simple Competitive Learning(SCL) algorithm which has binary reinforcement function and a constant adaptation gain is proposed. In contrast to the time-varing adaptation gain of the original Kohonen's SCL algorithm, the proposed algorithm uses a constant adaptation gain, and adds a binary reinforcement function in order to compensate for the lowered learning ability of SCL due to the constant adaptation gain. Since the proposed algorithm does not have the complicated multiplication, it's digital hardware implementation is much easier than one of the original SCL.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.100-102
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• 1998

This paper presents technique to control blower at constant air volume rate using V/F Control. Especially, this control method have not pressure sensors to measure because of using torque-speed relation based on the fan laws. Therefore, this technique is very simple and practical.

• Journal of Power Electronics
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• v.13 no.4
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• pp.609-618
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• 2013

This paper proposes a primary side constant power control scheme for TRIAC dimmer compatible LED drivers. The LED driver is a Flyback converter operated in boundary conduction mode (BCM) to minimize the switching loss. With the proposed control scheme, the input power of the Flyback converter can be controlled by the TRIAC dimming angle, which is not affected by AC input voltage variations. Since the output voltage is almost constant for LED loads, the output current can be changed by controlling the input power with a given conversion efficiency. The isolated feedback circuit is eliminated with the proposed primary side control scheme, which dramatically simplifies the whole circuit. In addition, the input current automatically follows the input voltage due to the BCM operation, and the resistive input characteristic can be achieved which is attractive for TRIAC dimming applications. Experimental results from a 15W prototype verify the theoretical analysis.

• Journal of Power Electronics
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• v.5 no.4
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• pp.272-281
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• 2005

In this paper, a simple power control scheme for a constant frequency Class-D inverter with a variable duty cycle is proposed. It is more suitable and acceptable for high- frequency induction heating (IH) jar applications. The proposed control scheme has the advantages of not only wide power regulation range but also ease of control output power. Also it can achieve a stable and efficient Zero-Voltage-Switching (ZVS) in a whole load range. The control principles of the proposed method are described in detail and its validity is verified through simulated and experimental results on 42.8kHz IGBT for induction heating rated on 1.6kW with constant frequency variable power.