• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.461-466
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• 2003

This paper presents the speed control of the surface-mounted permanent-magnet synchronous motors (SMPMSM) for the elevator drive. The elevator motor needs to be a compact and slim type. Essentially, the proposed scheme uses a vector control algorithm for a speed and torque control. This system is implemented using a high speed 32-bit DSP (TMS320C31-50), a high-integrated logic device FPGA (EPF10K10-Tl144-3) to design compactly and Inexpensively The proposed scheme is verified through digital simulation and experiments for a three-phase 13.3kW SMPMSM as a MRL(MachineRoomless) elevator motor ill the laboratory. Finally, experiment of the test tower was performed with a 48kW PWM converter-inverter system for a high- speed elevator .

• Journal of Power Electronics
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• 제16권4호
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• pp.1375-1386
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• 2016

To decouple the secondary saliencies in sensorless permanent magnet synchronous machine (PMSM) drives, a repetitive control (RC) in the angle domain is proposed. In this paper, the inductance model of a concentrated windings surface-mounted PMSM (cwSPMSM) with strong secondary saliencies is developed. Due to the secondary saliencies, the estimated position contains harmonic disturbances that are periodic relative to the angular position. Through a transformation from the time domain to the angle domain, these varying frequency disturbances can be treated as constant periodic disturbances. The proposed angle-domain RC is plugged into an existing phase-locked loop (PLL) and utilizes the error of the PLL to generate signals to suppress these periodic disturbances. A stability analysis and parameter design guidelines of the RC are addressed in detail. Finally, the proposed method is carried out on a cwSPMSM drive test-bench. The effectiveness and accuracy are verified by experimental results.

• 대한전기학회논문지:전력기술부문A
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• 제49권5호
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• pp.212-219
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• 2000

This paper deals with a systematic approach to GA-PI controller design for static VAR compensator(SVC) using genetic algorithms(GAs) which are search algorithms based on the mechanics of natural of natural selection and natural genetics, to improve system stability. A SVC, one of the Flexible AC Transmission System(FACTS), constructed by a fixed capacitor(FC) and a thyristor controlled reactor(TCR), is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage. To verify the robustness of the proposed method, considered dynamic response of generator used deviation and generator terminal voltage by applying a power fluctuation and three-phase fault at heavy load, normal load and light load. Thus, we proved usefulness of GA-PI controller design to improve the stability of single machine-infinite bus with SVC system.

• 대한전기학회논문지:전력기술부문A
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• 제50권7호
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• pp.324-332
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• 2001

In this paper, it is suggested that the selection method of parameter of Power System Stabilizer(PSS) with robustness in low frequency oscillation for Static VAR Compensator(SVC) using a Real Variable Elitism Genetic Algorithm(RVEGA). A SVC, one of the Flexible AC Transmission System(FACTS), constructed by a fixed capacitor(FC) and a thyristor controlled reactor(TCR), is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage. The proposed PSS parameters are optimized using RVEGA in order to maintain optimal operation of generator under the various operating conditions. To decrease the computational time, real variable string is adopted. To verify the robustness of the proposed method, we considered the dynamic response of generator speed deviation and generator terminal voltage by applying a power fluctuation and three-phase fault at heavy load, normal load and light load. Thus, we prove the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권11호
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• pp.547-554
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• 2006

The detent force of a permanent magnet linear motor(PMLM) consists of the end force and cogging force, and should be reduced for high precision purpose applications. The cogging force comes from the electromagnetic interaction between the permanent magnets and interior teeth(or the slots) of the stator, and of which the magnitude depends on the ratio of the numbers of the armature and permanent magnet poles as well as the geometrical shape of the permanent magnet and armature pole. In order to reduce the cogging force of a PMLM, this paper proposes a new configuration which has 9 permanent magnet poles and 10 armature winding slots. By theoretical investigation of the principle of cogging force generation and simulating using finite element method, the proposed PMLM configuration is proven to give much less cogging force than the conventional configuration which has 8 permanent magnet poles and 12 armature winding slots. A proper winding algorithm, modified (A, A, A) winding method, for the proposed configuration is also suggested when the proposed PMLM is operating as a 3 phase synchronous machine. A theoretical and numerical calculation shows that the proposed configuration makes slightly bigger back-emf and thrust force under same exciting current and total number of winding turns condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.226-228
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• 2002

This paper presents a new control approach for designing a coordinated controller for static VAR compensator system. A SVC constructed by a Fixed Capacitor and a Thyristor Controlled Reactor is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage. A design of linear quadratic controller based on optimal controller depends on choosing weighting matrices. A coordinated optimal controller is achieved by minimizing a quadratic performance index using dynamic programming techniques. The selection of weighting matrices is usually carried out by trial and error which is not a trivial problem. We proposed a efficient method using GA of finding weighting matrices for optimal control law. Thus, we prove the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.331-334
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• 2006

Air foil bearings have been attempted for application to industrial turbo machines, since they have several advantages over oil bearings in terms of endurance, simplicity, environment-friendliness, efficiency, sound and vibration, and small turbo machines with air foil bearings are in the market as the result. Recently, researches on widening the application spectrum of air foil bearings are in progress worldwide. In this paper, a 300 HP class turbo blower using air foil bearings is introduced. The turbo blower has a high speed PMSM(Permanent Magnet Synchronous Motor) driving a compressor, and air flow rate is designed to be $180\;m^3/min$ at pressure ratio of 1.6. The maximum rotational speed is set to 17,000 RPM to maximize the total efficiency with the result that the weight of rotor assembly is 26kg, which is expected to be the largest turbo machine with air foil bearings ever developed in the world.

• 전자공학회논문지SC
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• 제46권4호
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• pp.39-48
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• 2009

전역 클럭 없이 동작하는 비동기 순차 머신은 동기 순차 머신에 비해서 속도나 에너지 소비 면에서 장점을 지닌다. 본 논문에서는 불확실한 상태 천이를 가지는 입력/상태 비동기 머신을 위한 견실 제어기를 제안한다. 논문에서 고려하는 비동기 머신은 모델 불확실성, 내부 고장 등으로 인해서 일부 영역의 상태 천이 함수가 불확실하다. 이번 연구에서는 이러한 비동기 머신을 표현하는 유한 상태 머신 식을 제안한 후 일반화된 도달가능성 행렬을 이용하여 머신의 폐루프 동작이 주어진 정상적인 모델의 동작과 일치하도록 하는 비동기 제어기가 존재할 조건을 규명한다. 또한 기존 연구 결과를 바탕으로 비동기 제어기의 설계 과정을 기술하고 폐루프 시스템의 안정 상태 동작을 분석한다.

• 전기학회논문지
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• 제56권2호
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• pp.233-239
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• 2007

As the Kyoto Protocol, which aims at reducing greenhouse gases in accordance to the UNFCCC, came into force, research on environment friendly energy resources has been a matter of concern worldwide. As a general power generation system, among renewable energy resources, that is interconnected and operated with power system, the wind turbine is emerging as an effective alternative. Since power capacity of the wind turbine has been steadily increasing and its relative importance is also increasing in total facility capacity, we cannot ignore its effect. Because controlling generation output in the wind turbine is not as easy as in the synchronous machine due to its facility characteristics and it generates irregular output fluctuations when interconnected with power system, system interconnection was difficult. But the effect of large capacity wind turbine on isolated power system like Jeju island is serious problem on the frequency stability. Accordingly, it is necessary to analyze the effects of wind turbine on system interconnection and assess the optimum capacity of wind turbine that satisfies the most important principle of stable power supply. This paper have analyzed the effects of wind turbine capacity increases on the system and suggested the method of the capacity to achieve its steady operation. And It is applied to the Jeju island.

• 한국안전학회지
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• 제15권2호
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• pp.63-69
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• 2000

The constraint conditions are the stator voltage and the stator current to operate the motor in the flux weakening region. The maximum current is limited by the inverter current rating and the machine thermal rating. Given DC link voltage to control the motor in the flux weakening the maximum voltage is determined by considering PWM strategy, dead time, voltage drop of the inverter switching device, and the margin of the voltage for current forcing. In this paper, the new method to determine the available maximum voltage is derived by the quantitative method and by considering the factors of the voltage drop. The proposed method to determine the maximum voltage is very useful to improve the stability of the motor system and to enlarge the speed operation region in the flux weakening operation. Therefore the utility of the maximum voltage is increased.