• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.93-97
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• 2005

This paper proposes a design of stepper motor control in microstep driven mode using FPGA (Field Programmable Gate Array) for hardware implementation. The methods to drive stepper motor in microstep excitation mode are to control of the controlling currents in each phase windings of stepper motor with reference signals. These reference signals are used for controlling the current levels, the required variation of current levels with rotor position can be obtained from the ideal linear or sinusoidal approximations to the static torque-displacement ($T-{\theta}$) characteristic curve. In addition, the hardware implementation of stepper motor controller can be designed uses VHDL (Very high speed integrated circuits Hardware Description Language) and synthesis using an Altera FPGA, FLEX10K family, EPF10K20RC240-4 device as target technology and use MAX+PlusII program for overall development. A multi-stack variable-reluctance stepper motor of Sanyo Denki is used in the experiments.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1907-1910
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• 2005

Coating thickness is an important variable that plays a role in product quality, process control, and cost control. Measurement of film thickness can be done with many different instruments. In this paper, we introduce the new eddy current system for measure the thickness of nonconductive coatings on nonferrous metal substrates. The experimental results are shown that the proposed system is able to measure thickness of plastic film coating on aluminum plates in the range of 0 to 1000 microns with satisfy sensitivities, linearity, resolution and stability of the system.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.330-335
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• 1998

In this paper the robust vector control method of induction motor for the purpose of improving the system performance deterioration caused by parameter variations is proposed. The estimations of the stator current and the rotor flux are obtained by the full order state observer with corrective prediction error feedback. and the adaptive scheme is constructed to estimate the rotor speed with the error signal between real and estimation value of the stator current. Adaptive sliding observer based on the variable structure control is applied to parameter identification. Consequently predictive current control and speed sensorless vector control can be obtained simultaneously regardless of the parameter variations.

• Proceedings of the KIPE Conference
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• 2001.12a
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• pp.11-14
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• 2001

Direct torque control (DTC) scheme provides a very quick torque response without the complex field-orientation block and inner current regulation loop. DTC is known as an appropriate scheme for high power induction motor drives because it can be used at lower switching frequency There are a major drawbacks with the application of DTC schemes it is large current harmonics due to flux drooping in a low speed range. In order to solve the problem, the fuzzy variable switching sector scheme are adopted in this paper. A meaningful contribution of this paper is to propose a simple realization scheme of the fuzzy variable switching sector technique. Experimental results show the effectiveness of this proposition.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.515-520
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• 2009

According to the operating characteristics of pump applications, they should exhibit high efficiency and energy saving capabilities throughout the whole operating process. A novel efficiency optimization control strategy is presented here to meet the high efficiency demand of a variable speed Permanent Magnet Synchronous Motor (PMSM). The core of this strategy is the excellent integration of mended maximum torque to the current control algorithm, based on the losses model during the dynamic and the grade search method with changed step by fuzzy logic during the steady. The performance experiments for the control system of a variable speed high efficiency PMSM have been completed. The test results verified that the system can reliably operate with a different control strategy during dynamic and steady operation, and the system exhibits better performance when using the efficiency-optimization control.

• Journal of Power Electronics
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• v.5 no.4
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• pp.282-288
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• 2005

In this paper, a new speed sensorless induction motor scheme which can estimate rotor speed and rotor resistance simultaneously is presented. The rotor flux with a low frequency sinusoidal waveform is used to conduct on-line simultaneous estimation of the rotor speed and rotor resistance. Hence the proposed sensorless control method is robust to rotor resistance variations. Also, the control scheme has no current minor loop to determine voltage references. It contributes to good control performance at low speeds. Some simulation results supported by experiments are given to show the effectiveness of this method.

• Journal of Power Electronics
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• v.15 no.2
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• pp.555-566
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• 2015

A TRIAC dimming LED driver that can control the brightness of LED arrays for a wide range of source voltage variations is proposed in this paper. Unlike conventional PWM LED drivers, the proposed LED driver adopts a TRIAC switch, which inherently guarantees zero current switching and has been proven to be quite reliable over its long lifetime. Unlike previous TRIAC type LED drivers, the proposed LED driver is composed of an LC input filter and a variable switched capacitance, which is modulated by the TRIAC turn-on timing. Thus, the LED power regulation and dimming control, which are done by a volume resistor in the same way as the conventional TRIAC dimmers, can be simultaneously performed by the TRIAC control circuit. Because the proposed LED driver has high efficiency and a long lifetime with a high power factor (PF) and low total harmonic distortion (THD) characteristics, it is quite adequate for industrial lighting applications such as streets, factories, parking garages, and emergency stairs. A simple step-down capacitive power supply circuit composed of passive components only is also proposed, which is quite useful for providing DC power from an AC source without a bulky and heavy transformer. A prototype 60 W LED driver was implemented by the proposed design procedure and verified by simulation and experimental results, where the efficiency, PF, and THD are 92%, 0.94, and 6.3%, respectively. The LED power variation is well mitigated to below ${\pm}2%$ for 190 V < $V_s$ < 250 V by using the proposed simple control circuit.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1512-1522
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• 2017

Switched reluctance motor (SRM) is suitable for electric vehicle (EV) applications with the advantages of simple structure, good overload capability, and inherent fault-tolerance performance. The SRM dynamic simulation model is built based on torque, voltage, and flux linkage equations. The EV model is built on the basis of the analysis of forces acting on a vehicle. The entire speed range of the SRM drive is then divided into constant torque and constant power areas. The command torque of the motor drive system is given according to the accelerator pedal coefficient and motor operation areas. A novel adaptive variable angle control is proposed to avoid the switching chattering between the current chopping control and angle position control modes in SRM drives for EV applications. Finally, simulation analysis and experimental results are conducted to verify the accuracy of the proposed simulation model and control strategy.

• Journal of Power Electronics
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• v.17 no.2
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• pp.315-322
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• 2017

LED is a promising new generation of green lighting with the advantages of high efficiency, good optical performance, long lifetime and environmental friendliness. A pulsating current can be used to drive LEDs. However, current with a high peak-to-average ratio is unfavorable for LEDs. A novel control scheme for the ac-dc critical conduction mode (CRM) flyback LED driver is proposed in this paper. By using the input voltage, output voltage and average output current to control the turn-on time of the switch, the peak-to-average ratio of the output current can be reduced. The operation principle is analyzed and an implementation circuit is put forward. Experimental results show the effectiveness of the proposed scheme.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2126-2128
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• 1997

In order to establish the robust current controller design technique of series wound motor driver system. This paper proposes a method of compensated Bang-Bang current control using a series wound motor driver system under improperly variable load. Real time implementation of compensated Bang-Bang current controller achieved. Concept design strategy of the control and PWM waveform generation algorithms are presented in the paper.