• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.108-115
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• 2015

This paper proposed a optimal current control method to improve efficiency of BLDC motors. The aim of the proposed method is to use the maximum torque operating method by increasing the effective voltage at the maximum torque point unlike existing SPM operating method. The proposed method is based on existing IPM maximum torque operating method grafting onto a square wave operating of SPM motors. As the method of increasing the effective output voltage from inverter using the maximum torque point, the proposed method is to improve efficiency of BLDC motors using the same amount of the existing current effectively. For this method, the maximum torque point is carried out by FEA and analysis of magnetic flux vector. In this paper, the prototype of general-purpose BLDC drive is manufactured and the performance characteristic and validity are verified.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.1
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• pp.41-45
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• 2012

Until now, most studies of foot moving or driving posture have been performed under laboratory driving conditions. But there are many different things between actual driving conditions and laboratory driving conditions because, in laboratory conditions, it is hard to consider vehicle's noise, vibration and people's psychology state while driving. Thus this study is performed through actual driving conditions. And while driving test, we recorded driver's foots with 2 cameras to investigate foots(left and right) heel point and how human foots move to control the three pedals : accel, brake and footrest.. Through driving test, the results of this study show that the position of driver's heel point isn't related to stature and tends to be generalized.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.1
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• pp.23-29
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• 2001

A BLDC motor has a serious drawback that torque pulsation is generated in every commutation period though it has many advatages compared to the conventional DC Motor. In this paper, the influence of commutation time on torque pulsation is studied. Generally in calculating the torque of BLDC motor, it is assumed that the decaying phase back EMF is constant, but the torque model considering decaying phase back EMF is introduced here. Through it, the torque in commutation period has torque pulsation component caused by commutation itself and it cannot be removed perfectly even if there is no current pulsation. To reduce the torque pulsation, a new method is proposed, which controls a point of commutation and the optimal point of commutation is found. Simulation shows that proposed method reduces the torque pulsation considerately.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.314-316
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• 2001

This paper present the position control method for the application of permanent magnet linear synchronous motor. Controller is designed as a conventional P-PI controller, but the extra information is used such as velocity and acceleration from motion profiles. The profiles comes from S-Curve which is an optimized point-to-point motion profiles to achieve fast motions with minimum vibration[2]. In this application, the targets of the position control are maximum 10um position error within 10msec after respective ending point of position profiles. The implementation of the controller has been done in full digital way. All the controller is designed on the DSP TMS320VC33 control board. To prove performance of the controller, the experiment was performed with a servo linear motor.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.5
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• pp.865-872
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• 2019

In this paper, we describe the Solar Car, Woongbi, which was created to participate in the World Solar Challenge(WSC) at the team NeulHaeRang of Korea National University of Transportation. The WSC is the world's largest solar car racing competition and has a separate automobile regulation and must be manufactured to meet the regulations. Therefore, the key point of the solar car design is to optimize the energy efficiency based on the regulations. The solar car's drive system consists of a solar array to convert solar energy into electric energy, a maximum power point tracker (MPPT) controller to track the converted electric energy to maximum output power, a battery to store the produced electric energy, a BLDC (Brushless DC) motor for driving the vehicle by converting energy into mechanical energy, and a motor controller for controlling the BLDC. The optimal design methods for solar energy conversion and electric driving system of battery, motor are presented in this paper.

• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.649-663
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• 2004

While a great number of studies on human motor control have provided a wide variety of viewpoints concerning the strategy of the central nervous system (CNS) in controlling limb movement, none were able to reveal the exact methods how the movement command from CNS is mapped onto the neuromuscular activity. As a preliminary study of human-machine interface design, the characteristics of human leg motion and its underlying motor control scheme are studied through experiments and simulations in this paper. The findings in this study suggest a simple open-loop motor control scheme in leg motion. As a possible candidate, an equilibrium point control model appears consistent in recreating the experimental data in numerical simulations. Based on the general leg motion analysis, the braking motion by the driver's leg is modeled.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.131-134
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• 2002

The optimum design technology using combind F.E.M and eauivalent circuit is so fast and accurate that it can be applied to the optimum rotor design of an inverter-fed induction motor in high efficiency motor making industry. The optimum characteristics fer a rotor slot model of a 3 phase inverter-134 nduction motor was previously verified by a time-step F.E.M. In this paper, four verification models with the design variables near the optimum point are designed to chech whether the characteristics of a slot model presented is not less than those of the near models. The outputs of whole models are analyzed in a time-step Finite Element Method and compared in the experimental test. The economical and efficient selecting method of design variables fur the computer simulation and experimental test is presented in order to assure the optimum point.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.339-341
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• 1999

This paper presents the gear ratio of wobble motor, accounting for finite friction in contact point. The gear ratio of a wobble motor is affected by rotor slip, which is a function of motive torque, excitation angle, and friction torque. The gear ratio of a wobble motor can be expressed as a constant term plus a term that accounts for rotor slip. The ideal gear ratio is constant term and is equal to the rotor radius divided by the distance between the center of the rotor and the center of the stator. The rotor-slip term is shown to be directly proportional to the contact point friction torque and inversely proportional to the square of the excitation voltage.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.49-53
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• 2007

In this study, we investigated experimentally the potential of a planer positioning mechanism with three degrees of freedom using a flexure guide and an electromagnetic linear motor. The goal was to produce a multi-axis positioning system with nanometric resolution over a 1-mm stroke. An $X-Y-\theta$ stage was designed based on previous results from a single-axis prototype and was constructed with a flexure guide mechanism and voice coil motor type linear actuators. We examined the necessity of a driving method and control system to ensure high resolution for multi-axis positioning. Experiments were conducted to evaluate the performance, and the results confirmed the mechanism's potential; fine point-to-point (PTP) positioning was achieved over a 1-mm stroke, with a resolution of 2 nm for translation in X-Y and 0.01 asec for yaw in $\theta$.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.2
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• pp.130-137
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• 1988

The technique of dual-input describing function's synthesis is introduced and the construction of a nonlinear compensator, based on this technique, is proposed. A nonlinear compensator, describing a complex DIDF depending upon amplitude of the second sinusoidal input signal only, is also proposed, where the second sinusoidal input signal is supplied to the nonlinear compensator by external generator. This compensator, connected in a closed loop of the PI speed control of DC motor, can improve the speed response in view instability limit cycle, low speed response and disturbance of the dynamic shift of the Nyquist's critical point -1 + j O. It is verified theoretically that the improvement of speed response of DC motor using the proposed compensator is achieved by means of the dynamic shift of the Nyquist's critical point on the complex plane, and the speed characterstics of DC motor is to be tested through experiment for its performance.