• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.190-191
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• 2017

본 논문에서는 소용량 직류단 커패시터를 갖는 인버터로 구동되는 매입형 영구자석 동기기의 속응성 향상을 위한 제어 기법을 제안한다. 제안하는 기법은 매입형 영구자석 동기기에서 요구되는 지령 전력을 통해 인버터 동작을 위한 지령 전압을 결정한다. 제안하는 제어 기법을 통해 매입형 영구자석 동기기의 속응성을 향상시킬 수 있다. 시뮬레이션을 통해 제안하는 기법의 타당성을 검증한다.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2268-2270
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• 2003

In this paper, mathematically modeled equations were derived for wind turbine under the analysis of aerodynamics. On the basis of these equations, maximum power controller is implemented by simulink in matlab. In order to achieving maximum power, variable speed control method is used for obtaining maximum power coefficient in the variable wind speed because we can have maximum changing efficiency in these coefficients. Also, the maximum power control of wind generator system uses a synchronous generator and a invertor circuit.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1124-1127
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• 2003

This paper proposes a sensorless vector control of interior permanent magnet synchronous motor(IPMSM) using a Luenberger observer. Linearizeng the motor model, we can construct the linear reduced order observer for estimating rotor position and disturbance torque. The validity of the proposed scheme is confirmed by various response characteristics.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.384-386
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• 2000

This paper describes a new approach to estimating permanent magnet synchronous motor(PMSM) speed and position from measured terminal voltages and currents for speed-sensorless vector control. The proposed system is based on observing the instantaneous reactive power of the motor. The described technique is very simple and robust to variations of motor parameters. The new approach is not dependent upon the value of the stator resistance. Also, MRAS schemes are chosen for determining the adaptive law for the speed and the position estimator. The effectiveness is verified by the experimental results.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1746-1752
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• 2014

This paper presents an application of proportional-resonant (PR) current controllers in modular multilevel converter-high voltage direct current (MMC-HVDC) system under unbalanced voltage conditions. The ac currents are transformed and controlled in the stationary reference frame (${\alpha}{\beta}$-frame). Thus, the complex analysis of the positive and negative sequence components in the synchronous rotating reference frame (dq-frame) is not necessary. With this control method, the ac currents are kept balanced and the dc-link voltage is constant under the unbalanced voltage fault conditions. The simulation results based on a detailed PSCAD/EMTDC model confirm the effectiveness of the proposed control method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.9
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• pp.1165-1173
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• 2018

Recently, owing to environmental problems and instability of rare earth resources market, non-rare earth electric motors are attracting attention. As a non-rare earth motor type, a wound rotor synchronous motor(WRSM) has high power density and wide driving range further it can reduce loss by field current control during field weakening control at high speed. However, since the d-axis flux of the WRSM is coupled with the rotor circuit, the fluctuation in the d-axis flux linkage affects the rotor circuit, which causes ripple of the field current and torque. In this paper, we propose the field current ripple compensation method by injecting the feedforward voltage. the proposed compensating method was demonstrated by simulation and experiments.

• Journal of Power Electronics
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• v.10 no.6
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• pp.733-738
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• 2010

This paper deals with a ride-through technique for permanent-magnet synchronous generator (PMSG) wind turbine systems using energy storage systems (ESS). A control strategy which consists of current and power control loops for the energy storage systems is proposed. By increasing the generator speed, some portion of the turbine power can be stored in the system inertia. Therefore, the required energy capacity of the ESS can be decreased, which results in a low-cost system. In addition, the power fluctuations due to wind speed variations can be smoothened by controlling the ESS appropriately. The effectiveness of the proposed method is verified not only by the simulation results for a 2[MW] PMSG wind turbine system, but also by the experiment results for a reduced-scale turbine simulator.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.494-495
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• 2012

본 논문은 LVRT 제어를 위한 계통 사고 상황에서도 정확한 위상각을 검출하기 위하여 일반화된 2차 적분기(Second Order Generalized Integrator)를 이용한 정상분 전압 검출을 기반으로 하며, 주파수 변동에도 강인성 제어가 가능한 DSOGI (Double Second Order Generalized Integrator) FLL(Frequency locked loop)을 제안한다. 실험을 통해 종래의 SRF(Synchronous reference frame) PLL, DSOGI PLL 제어와 비교, 분석을 통해 본 논문의 타당성을 입증한다.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2314-2316
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• 2001

The steam gererator which produces thermal energy from coal or gas is a very important device in power plants, including the turbine driving synchronous generator which transforms kinetic energy into electrical energy. The turbine and the generator are driven by many kinds of media according to the types of which power plants are classified into steam turbine generator, gas turbine generator, water turbine generator and so on. This paper introduces the overspeed protection as well as the various speed and load control methods of some types of turbines.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1398-1400
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• 2005

In this paper, a modular dc-to-dc converter, in order to apply to the control board of train vehicles, is presented. Forward converter with active-clamp reset circuit and synchronous rectifier(SR) is employed to achieve high efficiency. To reduce the size and height of the converter, low profile magnetic components are used. The design and performance of the modular dc-to-dc converter with experiments on a 50W(5V/10A) prototype for the 60V$\sim$140V input voltage range are presented.