• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.217-219
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• 2007

본 논문에서는 열차의 실제 노선 운행을 모의하여 구동 장치의 특성을 평가하고 에너지 절약에 대한 연구를 하였다. 이에 대하여 열차의 구동 에너지를 절약하기 위한 모터의 제어 방식과 제너레이터의 회생 에너지에 관한 연구를 선택하였다. 실제 대전 지하철의 노선 데이터를 이용하여 열차 주행 결과를 시뮬레이션 하였다. SVM (Space Vector Modulation) - DTC (Direct Torque Control)로 구현된 M-G Set으로 열차가 주행 시 모터에서 소비되는 에너지와 제동 시 제너레이터에서 발생되는 회생 에너지를 Simplorer 프로그램을 이용하여 시뮬레이션 하였다. 시뮬레이션 결과를 통해 열차의 소비 에너지와 회생 에너지를 연구한다.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.406-408
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• 2007

현재 국가물류 수송의 경쟁력 향상과 증가되는 교통수요에 부응하기 위해 경부 고속철도의 건설 등 철도의 고속화와 수송량 증대에 많은 관심과 투자가 이루어지고 있지만, 점점 상승하는 유가 에너지 비용에 대한 문제가 발생하고 있어 전기 철도차량의 개발이 시급하다. 본 논문은 Simplorer 프로그램을 이용하여 열차 추진 장치에 관한 연구와 추후 열차 회생 에너지에 관한 연구를 하기 위해 추진 장치를 M-G set으로 구성 하였고 모터는 SVM(Space Vector PWM)방식으로, 제너레이터는 DTC(Direct Torque Control) 방식으로 제어하였다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.393-394
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• 2017

유도전동기는 속도 제어가 어렵기 때문에 이를 위한 고가의 벡터제어 인버터가 널리 사용되어 왔다. 이 때문에 최근에는 이를 저가화하기 위하여 제어 알고리즘이 단순하고 구현이 용이한 직접토크제어 방식에 대한 연구가 이루어지고 있다. 한편으로 소용량의 저전력 응용 분야에서는 기계적으로 구조가 단순하고 가격이 저렴한 2상 유도전동기를 적용하려는 노력이 활발해지고 있다. 2상 유도전동기용 인버터의 대표적인 토폴로지는 3상 IPM 소자를 그대로 이용할 수 있는 3레그형이다. 그러나, 3레그형 인버터에서는 출력 전압 벡터가 비대칭 육각형의 형태로 나타나므로 2상 유도전동기에 이러한 직접토크제어 방식을 적용하면 전동기의 발생 토크에 리플이 증가하는 문제가 있다. 본 논문에서는 3레그형 인버터를 사용하는 2상 유도전동기에 직접토크제어 방식을 적용하고 이때 문제가 되는 전동기의 토크 리플을 저감하는 방법에 관하여 연구하였으며, 이것의 유효성은 시뮬레이션을 통하여 유효성을 검증하였다.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1145-1147
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• 2003

본 논문에서는 신경망을 이용한 리럭턴스 동기 전동기(Reluctance Synchronous Motor, RSM)의 자속 보상에 대한 알고리즘을 제시한다. 리럭턴스 동기 전동기의 안정적인 운전을 위해서는 자속 정보가 필수적이다. 그러나 실질적으로 추정된 자속은 스위칭 노이즈 등의 성분을 포함하고 있어서 정밀한 전동기 제어에 많은 문제점을 야기하고 있다. 특히 속도 센서없는 전동기의 운전이나 직접토크제어(Direct torque control, DTC) 등의 제어에 있어서는 자속의 노이즈 성분을 제거하기 위해서 여러 가지 필터들이 사용되고 있지만, 이러한 필터들은 위상지연과 진폭 보상이 필연적으로 이루어져야한다. 이에 따라 본 연구에서는 1.0[Kw] RSM의 자속보상을 위해 신경망을 사용하고, 제시된 자속 보상방법의 타당성을 위해서 속도센서없는 직접토크 제어를 이용하여 전동기의 동특성을 검증하였다.

• International Journal of Control, Automation, and Systems
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• v.4 no.4
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• pp.414-427
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• 2006

This paper presents an adaptive feedback linearization control scheme for induction motors with simultaneous variation of rotor and stator resistances. Two typical modeling techniques, rotor flux model and stator flux model, have been developed and successfully applied to the controller design and adaptive observer design, respectively. By using stator fluxes as states, over-parametrization in adaptive control can be prevented and control strategy can be developed without the need of nonlinear transformation. It also decrease the relative degree for the flux modulus by one, thereby, yielding, a simple control algorithm. However, when this method is used for flux observer, it cannot guarantee the convergence of flux. Similarly, the rotor flux model may be appropriate for observers, but it is not so for adaptive controllers. In addition, if these two existing methods are merged into overall adaptive control system, it brings about structural complexies. In this paper, we did not use these two modeling methods, and opted for the airgap flux model which takes on only the positive aspects of the existing rotor flux model and stator flux model and prevents structural complexity from occuring. Through theoretical analysis by using Lyapunov's direct method, simulations, and actual experiments, it is shown that stator and rotor resistances converge to their actual values, flux is well estimated, and torque and flux are controlled independently with the measurements of rotor speed, stator currents, and stator voltages. These results were achieved under the persistent excitation condition, which is shown to hold in the simulation.

• Smart Structures and Systems
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• v.29 no.5
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• pp.661-675
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• 2022

In this paper, an electric vehicle drives with efficient control and low cost hardware using four quadrant DC converter with Permanent Magnet Direct Current (PMDC) motor fed by DC boost converter is presented. The main idea of this work is to improve the energy efficiency of the conversion chain of an electric vehicle by inserting a boost converter between the battery and the four quadrant-DC motor chopper assembly. Consequently, this method makes it possible to maintain the amplification gain of the 4 quadrant chopper constant regardless of the battery voltage drop and even in the presence of a fault in the battery. One of the most important control problems is control under heavy uncertainty conditions. The higher order sliding mode control technique is introduced for the adjustment of DC bus voltage and mechanical motor speed. To implement the proposed approach in the automotive field, experimental tests were carried out. The performances obtained show the usefulness of this system for a better energy management of an electric vehicle and an ideal control under different operating conditions and constraints, mostly at nominal operation, in the presence of a load torque, when reversing the direction of rotation of the motor speed and even in case of battery chamber failure. The whole system has been tested experimentally and its performance has been analyzed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.481-488
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• 2000

This paper presents a new passive gravity -compensating system for articulated robot manipulators. The system, which consists of linear zero- free -length springs, achieves exact counterbalancing o f the gravitational loads throughout the entire range of the manipulator workspace, A basic concept is to design springs such that the total potential energy of the system including the manipulator and the springs should be maintained constant. A prototype has been developed for a direct-drive five-bar manipulator and its performances have been investigated. Results show that the gravity-induced motor torques have been reduced to less than 5% of those of uncompensated robots. Also, the gravity-compensating system simplifies the position control algorithm while maintaining the trajectory-tracking errors in a satisfactory level. In conclusion, the proposed system efficiently improves the manipulator performances by reducing the driving motor size and the energy consumption as well as by simplifying the control systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.487-492
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• 2000

This paper presents a novel method of slip-compensation for rotor time constant variation in indirect field orientation control of induction motor drives. In field oriented control due to variation of rotor time constant, decoupling between the flux and torque components of stator current is lost and hence, the performance of operation of the machine deteriorates. To solve the problem, the q-axis is aligned to reference frame without phase difference by comparing the real flux component with the reference flux component. Then to compensate the slip, PI controller is used. The proposed method keeps a constant slip by compensating the gain of direct slip frequency when the rotor resistance of induction motor varies. To prove the validations of the proposed algorithm in the paper, computer simulations and experiments are executed.

• Journal of Power Electronics
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• v.16 no.1
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• pp.205-216
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• 2016

The manufacturing sector resorts to automation to increase production and homogeneity of products during mass production, without increasing scarce, expensive, and unreliable manpower. Automation in the form of multiple robotic arms that handle materials in all directions in different stages of the process is proven to be the best way to increase production. This paper thoroughly investigates robotic single-arm movements, that is, 360° vertical rotation, with the help of a brushless DC motor, controlled by a fuzzy proportional-integral-derivative (PID) controller. This paper also deals with the design and performance of the fuzzy-based PID controller used to control vertical movement against the limited scope of conventional PID feedback controller and how the torque of the arm is affected by the fuzzy PID controller in the four quadrants to ensure constant speed and accident-free operation despite the influence of gravitational force. The design was simulated through MATLAB/SIMULINK and integrated with dSPACE DS1104-based hardware to verify the dynamic behaviors of the arm.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.172-174
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• 1994

Due to the environmental considerations and the energy crisis, there has been a revival of electric vehicles since 1960s. Research and development work concerning with electric vehicles (EVs) was becoming more intense in last decade. As compared with conventional internal combustion engine (ICE) cars, EVs have the advantages of clean, quiet, better energy efficiency, less maintenance and improving the load factor of electric power systems. However, EVs usually have a snort running range, bad acceleration performance and high initial cost. The main reason for these shortcomings is the low figure of energy density and the high per energy cost of battery at present technology state. So it is very important to optimize the overall drive system design with respect to the maximum utilization of battery, energy, motor torque and inverter power. This paper describes a demonstration model of electric car which is driven by 4-wheel direct method using the vector control.