• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.201-206
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• 2020

This paper presents a new method for controlling the current of lighting LEDs without current sensors. This method can be used as backup against LED current sensor faults. LED lighting requires a circuit with a constant current in order to maintain the same brightness when the ambient temperature changes. Therefore, we propose a new current estimation method to provide backup in case of current sensor faults based on the calculation of the inductor current. In the fabricated circuit, the average current changes from 144.03 mA to 155.97 mA when the ambient temperature changes from 0℃ to 60℃. The application of this study can enable the fabrication of a driving IC for LEDs in the form of a single chip without sensing resistors. This is expected to reduce the complexity of the peripheral circuit and enable precise feedback control.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.186-189
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• 2003

This paper is proposed to position and speed control of interior permanent magnet synchronous motor(IPMSM) drive without mechanical sensor. A gopinath observer is used for the mechanical state estimation of the motor. The observer was developed based on nonlinear model of IPMSM, that employs a d-q rotating reference frame attached to the rotor, A gopinath observer is implemented to compute the speed and position feedback signal. The validity of the proposed scheme is confirmed by various response characteristics.

• Proceedings of the KIEE Conference
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• 2001.07e
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• pp.47-52
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• 2001

This paper presents a high-performance control system for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The system consist of stator flux observer, rotor position/speed estimator, torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source inverter, and F240/C31DSP controller by using fully integrated control software. The stator flux observer is based on the combined voltage and current model with stator flux feedback adaptive control that inputs are current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated by the observed stator flux-linkage space vector. The estimated rotor speed can be determinated by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operating area. To prove the suggested control algorithm, we have a simulation and testing at actual experimental system. The developed digitally high-performance position sensorless control system are shown a good motion control response characteristic results and high performance features using 1.0Kw RSM.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.60-63
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• 1997

A new approach to the position sensor elimination of PM synchronous motor drives is presented in this study. Using the position sensing characteristics of PMSM itself, the actual rotor position as well as the machine speed can be estimated by adaptive flux observer and used as the feedback signal for the vector controlled PMSM drive. The adaptive speed estimation is achieved by model reference adaptive technique. The adaptive laws are derived by the Popov's hyperstability theory and the positivity concept. In order to verify the effectiveness of the proposed scheme, computer simulations are carried out for the actual parameters of a PM synchronous motor and the results well demonstrate that the proposed scheme provides a good estimation value of the rotor speed without mechanical sensor. It is also shown that the actual rotor position as well as the machine speed can be achieved under the variation of the magnet flux linkage. Since the flux linkages are estimated by the adaptive flux observer and used for the identification of the rotor speed, robust estimation of the rotor speed can be performed.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.244-247
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• 2003

This paper is proposed to position and speed control of interior permanent magnet synchronous motor(IPMSM) drive without mechanical sensor. A minimum order state observer is used for the mechanical state estimation of the motor. The observer was developed based on nonlinear model of IPMSM, that employs a d-q rotating reference frame attached to the rotor. A minimum order state observer is implemented to compute the speed and Position feedback signal. The validity of the proposed sensorless scheme is confirmed by various response characteristics.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.4
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• pp.453-459
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• 1995

In this paper, a novel dead time compensation method is presented which produces inverter output voltages equal to reference voltages. An experimental result is also presented to demonstrate the validity of the proposed method. It shows that the compensation of the dead time is possible up to a sub-microsecond range. And the reference voltage can be used as a feedback value, which is essential for sensorless vector control and flux estimation. The method is based on space vector PWM strategy and can be carried out automatically by an inverter controller for initial set-up without any extra hardware.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.294-295
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• 2007

80년대 초에 개발된 CD(Compact Disc) Disc는 지난 27여 년간 급속한 발전을 하였다. 95년에 DVD가 발표되면서 영화 Title제작이 되어 우리는 안방에서 고화질의 DVD를 감상할 수 있었다. CD-R(Recordable) 로부터 시작된 기록 기술은 CD-RW를 거쳐 DVD-Recordable, DVD-ReWritable 및 DVD-RAM, Light Scribe등 거쳐 BD(Blu-Ray) 기술에 까지 이르게 되었다. 광 Disc 기술은 3가지 분야로 나눌 수 있다. 안정된 제어를 위한 Servo 기술, Mechanical 기술, PC와communication 할 수 있는 Interface 기술 등으로 나눌 수 있다. Servo 제어 기술은 다음과 같이 4가지 분야로 구성되어 있다. Focus Servo, Tracking Servo, Sled Servo, Spindle Servo. Disc 회전을 제어를 담당하고 있는 Spindle Servo Block에서는 Hall Sensor를 이용하여 Disc의 회전을 Count하여 Feedback 하였다. 그러나 갈수록 심화 되고 있는 가격 경쟁 상황에서 Hall Sensor를 대체하여 회전수를 Conut하는 방법이 필요 하였다. BEMF(역기전력)을 이용한 Zero Crossing 방법이 이를 대체 하였지만, Motor의 전기적인 특성 편차 등에 안정된 control이 안되어서, Motor를 관리하는 방법으로 진행되어 왔다. 이것은 생산 Loss로 이어져서 Hall Sensorless의 장점을 훼손하게 되었다..본 논문에서는 이러한 Sensorless Type Spindle Motor의 문제점에 대해 Common 단자를 이용하여 안정된 제어 방법을 제안 한다. less Type의 문제점인 초기 기동 문제를 Common 단자를 이용하여 안정되게 Spindle motor를 Control 하는 방법에 대해 연구 하고자 한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.109-116
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• 2005

The high performance drives of the slotless Permanent Magnet Brushless DC(PM BLDC) motor can be achieved by the current control, where the currents flow according to the rotor position and the current phase is suitably controlled according to the operational condition. Rotor position information can be provided by Hall-IC or sensorless algorithm. So, the Hall-ICs are set up in this motor to detect the main flux from the rotor. Instead of using three Hall-ICs and encoder, this paper uses only two Hall-ICs for the permanent magnet rotor position and the speed feedback signals, and uses a micro-controller of 16-bit type (80C196KC). Also because of low resolution obtained by using Hall-IC even low-cost and simple structure, to improve the wide range of speed response characteristic more exactly, we propose the rotor position signal synthesizer using PLL circuit based on two Hall-ICs.