• 융합신호처리학회논문지
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• 제4권2호
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• pp.61-69
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• 2003

본 논문에서는 반도체 소자의 DC 파라메터에 대한 특성을 검사하는 DC 파라메터 검사 시스템을 개발하였다. 개발된 시스템은 IBM-PC와 연결하기 위한 CPLD(Complex Programmable Logic Device)로 구현된 연결부와 ADC/DAC부, 전압원/전류원, 가변저항부, 측정부로 구성되어 있다. 제안된 시스템에서 정전압원과 정전류원은 하나의 회로로 설계하여 외부의 컴퓨터에서 주어지는 모드명령에 의해 선택되도록 하였으며, VHDL(VHSIC Hardware Description Language)을 사용하여 회로를 제어하고 신호를 변환하는 기능을 CPLD로 설계하였다. 제안된 시스템은 두 개의 채널을 가지고 있으며, VFCS(Voltage Force Current Sensing) 모드와 CFVS(Current Force Voltage Sensing) 모드로 동작할 수 있도록 하였다. 검사 전압의 범위는 0(V)-10(V)까지이고, 검사전류의 범위는 0[mA]-100[mA]까지로 다이오드를 사용하여 설계된 회로의 성능을 검증하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.852-857
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• 2004

In this paper, an angular self-sensing algorithm is proposed and implemented to a Lorentz force type integrated motor-bearing system. It is based on the principle that the flux linkages of stator windings, calculated from the voltage and torque control current, are the functions of the rotor angle. The tracking angular position error is proven to vanish using the Lyapunov stability method, and the experimental results show that the initial error decays within about 5 seconds. It is found that the resolution of the algorithm remains about 1º over the speed range of 100 to 1000 rpm.

• Journal of Electrical Engineering and Technology
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• 제1권1호
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• pp.52-57
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• 2006

In this paper, a new 'impedance sensing' method is described. This method overcomes the shortcomings of the impedance sensing method. According to the new method, sensing voltage pulse is applied to the idle phase in the minimum inductance region and the beginning of the increasing inductance region to detect rotor position. The negative torque produced by the sensing voltage pulse can be neglected in the minimum inductance region and the efficiency of SRM is improved. In the minimum inductance region the back electromotive force (EMF) can be neglected. And in the increasing inductance region the EMF opposes the rise of current in the phase, so the position estimation scheme is reliable. Therefore the new 'impedance sensing' method is sufficiently precise even under the high back EMF effect. The adjustment of turn-on angle and turn-off angle is also easy to be realized. The technique is very useful in applications where cost or size is primary concerns, such as electric bicycle drives. Experimental results are presented to verify the proposed method.

• 제어로봇시스템학회논문지
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• 제21권10호
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• pp.910-916
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• 2015

A sensorless motor control scheme with conventional back-Electro Motive Force (EMF) sensing based on zero crossing point (ZCP) detection has been widely used in various applications. However, there are several problems with the conventional method for effectively driving sensorless brushless motors. For example, a phase mismatch of 30 degrees occurs between the ZCP and commutation time. Additionally, most of the motor speed/current controls are achieved based on a pulse width modulation (PWM) method, which generates significant noise that distracts the back-EMF sensing. Due to the PWM switching, the ZCP is not deterministic, and thus the efficiency of the motor is reduced because the phase transition points become uncertain. Moreover, the motor driving performance is degraded at a low speed range due to the effect of PWM noise. To solve these problems, an improved back-EMF detection method based on a differential line method is proposed in this paper. In addition, the proposed sensorless BLDC driver addresses the problems by using a variable voltage driver generated from a buck converter. The variable voltage driver does not generate the PWM switching noise. Consequently, the proposed sensorless motor driver improves 1) the signal-to-noise ratio of back-EMF, 2) the operation range of a BLDC motor, and 3) the torque characteristics. The proposed sensorless motor driver is verified through simulations and experiments.

• 한국소음진동공학회논문집
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• 제18권10호
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• pp.1065-1072
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• 2008

A HDD adopts a sensorless brushless DC (BLDC) motor as a spindle motor. Because there is no direct sensor measuring rotor position. open loop commutations with inductive sensing are used to increase the rotor speed up to a certain speed where the zero crossings of the back electromotive force (EMF) voltage are measurable. Therefore, successful open loop commutations are necessary for the stable start-up control of the spindle motors. In this paper, the time scale and the number of the open loop commutations are employed for design parameters to guarantee robustness to torque constant variation and initial rotor position. The design results are verified by experiments on a very low current start-up of the spindle motor with various environment. The experimental results show that the design results can decrease the start-up failure rate considerably.