• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.210-216
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• 2009

Distributed Generation (DG) is predicted to play a important role in electric power system in the near future. insertion of DG system into existing distribution network has great impact on real-time system operation and planning. It is widely accepted that micro turbine generation (MTG) systems are currently attracting lot of attention to meet customers need in the distributed power generation market. In order to investigate the performance of MT generation systems, their efficient modeling is required. This paper presents the modeling and simulation of a MT generation system suitable for stand-alone operation. The system comprises of a permanent magnet synchronous generator driven by a MT. A brief description of the overall system is given, and mathematical models for the MT and permanent magnet synchronous generator are presented. Also, the use of power electronics in conditioning the power output of the generating system is demonstrated. Simulation studies with MATLAB/Simulink have been carried out in stand-alone operation mode of a DG system.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1270-1277
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• 2019

A problem with virtual synchronous generator (VSG) systems is that they are difficult to operate stably with photovoltaic (PV) power as the DC side. With this problem in mind, a PV-VSG control strategy considering the dynamic characteristics of the DC side is proposed after an in-depth analysis of the dynamic characteristics of photovoltaic power with a parallel energy-storage capacitor. The proposed PV-VSG automatically introduces DC side voltage control for the VSG when the PV enters into an unstable working interval, which avoids the phenomenon where an inverter fails to work due to a DC voltage sag. The stability of the original VSG and the proposed PV-VSG were compared by a root locus analysis. It is found that the stability of the PV-VSG is more sensitive to the inertia coefficient J than the VSG, and that a serious power oscillation may occur. According to this, a new rotor model is designed to make the inertial coefficient automatically change to adapt to the operating state. Experimental results show that the PV-VSG control strategy can achieve stable operation and maximum power output when the PV output power is insufficient.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1081-1088
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• 2022

The harmonics of synchronous generators increase iron and copper loss, which is the cause of fever. For harmonic reduction, the armature winding method is used as a distribution winding, a short pitch winding. In this paper, we want to improve the waveform of the instrument voltage by reducing the harmonics in a new way to the shape of the permanent magnet. The method cuts both ends of the permanent magnet and adjusts the air gap by increasing and decreasing the area according to the set value. By varying the distribution of magnetic flux density, the resulting electromotive voltage and strain were compared. This compares the shape-changing models of permanent magnets and shows an effective deformation method.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.181.2-181.2
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• 2010

포항공과대학교 풍력특성화대학원에서는 STX Windpower의 풍력발전기 국산화 사업의 일환으로 2MW 직접 구동형 영구자석 동기발전기의 설계를 변경 하였다. 정격 출력 2.3MW급으로 정격 RPM은 16.5, 고정자 내경은 2.1m로 128극을 가지고 있다. 본 설계 발전기는 STX93 모델을 기반으로 하고 있으며, 기존 발전기보다 더 compact하고 더 높은 효율의 발전기로 설계 변경하였다. 본 논문에서는 발전기 물리 설계와 그에 따른 전자기 해석 및 열 분석을 수행하고 손실을 계산한다. 또한, 그 결과와 절차에 대하여 요약하고 기존 발전기와 설계 발전기를 비교 분석한다.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1358-1366
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• 2015

This study focuses on an advanced second-order sliding mode control strategy for a variable speed wind turbine based on a permanent magnet synchronous generator to maximize wind power extraction while simultaneously reducing the mechanical stress effect. The control design based on a modified version of the super-twisting algorithm with variable gains can be applied to the cascaded system scheme comprising the current control loop and speed control loop. The proposed control inheriting the well-known robustness of the sliding technique successfully deals with the problems of essential nonlinearity of wind turbine systems, the effects of disturbance regarding variation on the parameters, and the random nature of wind speed. In addition, the advantages of the adaptive gains and the smoothness of the control action strongly reduce the chatter signals of wind turbine systems. Finally, with comparison with the traditional super-twisting algorithm, the performance of the system is verified through simulation results under wind speed turbulence and parameter variations.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.93-100
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• 1999

Wide operating range and speed control is needed for wind power generating and a Doubly Fed Induction Generator(DFlG) has good adaptivity for that purpose. Ths paper investigates speed and output stator power control using a grid connected to a DFlG in super-synchronous speed regions, by control of both magnitude and frequency of the voltage fed to the rotor. For the speed control analysis, torque simulation is perforrred whereby the different slip between qJernting rmtor driving frequency and synchronous frequency of M-G system awlied. To keep the output rating of the generator, the exciting frequency and voltage attenuation are arolied.rolied.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1043-1044
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• 2011

This paper discusses the electromagnetic and mechanical design considerations to improve the design accuracy and power to mass ratio of multi-stack axial flux permanent magnet synchronous generator (AFPMSG). Design accuracy of multi-stack AFPMSG for direct drive wind turbine application is improved by considering magnetic flux leakages and fringing effect. FEM structural analysis is utilized to increase power to mass ratio of three-stack AFPMSG by reducing the rotor yoke thickness considering magnetic and centrifugal forces and Von Mises stress distribution.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.882-883
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• 2011

This paper deals with comparison on Electromagnetic losses of slotted and slotless high-speed PM Machine for Micro Turbine. Losses are consist of core losses, copper losses and eddy current losses. We are using both analytical method and 2D Finite Element Method for more detailed losses analysis. And then We compare Electromagnetic losses of slotted and slotless PM synchronous machine. This machine has designed of a generator of 800W, 400000rpm and a starter of 400W, 200000rpm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.7
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• pp.916-923
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• 2014

This paper proposes a low-cost switched-mode rectifier (SMR) for a small-scale wind turbine with a permanent magnet synchronous generator (PMSG) system. Also, a sensorless Fuzzy MPPT control is realized by the proposed system. In the PMSG system with the SMR, the synchronous impedance can be replaced as the input inductor of a boost converter. Moreover, the sensorless MPPT control using the Fuzzy technique is carried out by the duty-ratio regulation of the SMR. The relation between the generating power and the duty-ratio is ruled by the chain rule. The wind turbine model is implemented by the squirrel cage induction motor and generated the variable torque when the generator speed is varied. To verify the performance of the proposed system, simulation and experimental results are executed.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.93-94
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• 2011

The use of boost chopper in Permanent Magnet Synchronous Generator (PMSG) aims to capture maximum power at any wind speed condition. It is reached by adjusting the duty cycle of boost chopper. In this paper, fuzzy logic algorithm is used to find the duty cycle value which yields the maximum power output. This control scheme is verified by PSIM simulation. Another MPPT method is also simulated as a comparison.