• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1058-1059
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• 2015

This paper describes a low-voltage ride-through method for the permanent magnet synchronous generator (PMSG) wind turbine system at a grid fault. The generator side converter regulates the DC link voltage instead of the grid side converter by storing the surplus active power in the rotor inertia during grid fault by the sliding mode controller. The grid side converter controls the grid active power keeping a maximum power point tracking. Simulation results for small scale PMSG wind turbine verify the efficiency of the control method.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.170-173
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• 2002

A variable speed wind turbine simulator is designed and implemented for the simulation of wind power generation system. The control algorithm decides the shaft torque delivered to generator taking into consideration the wind speed, the generator rpm, and the rotor blade inertia. It is shown that the proposed control algorithm can emulate the dynamic behavior of actual wind turbine through simulations and experimental.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.163-168
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• 2007

For an accurate computer simulation to motor drive systems, the target mechanical load system driven by a motor needs to be model its characteristics accurately. In general, a load system is modeled simply with system parameters such as approximated system inertia and friction. So, simulation results have some errors compared with experimental results for a real load system. RecurDyn is a mechanics simulation program for 3-dimension analysis to mechanical load systems. From this program, parameters such as a load torque, a system inertia and a viscous friction can be obtained accurately which are required to model a mechanical system. Also, this program operates together Matlab/Simulink which is used to simulate electrical motor drive systems. So, an accurate simulation for the whole system with a motor drive system and a mechanical load is possible. This paper introduces an application of RecurDyn program to an electric forklift drive system using IPMSM(Interior Permanent Magnet Synchronous Motor) and examines the feasibility of co-simulation it with Matlab/Simulink.

• 전기의세계
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• v.26 no.4
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• pp.8-11
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• 1977

공업기술의 발전에 따라 전동기의 용도도 다양화되고 기계의 기진 정상 정전에서 역전으로 바꾸는것을 기계적 방법보다 전동기의 기동제동 plugging운전방법으로 이송할 때 기계의 고효율화, 기구의 간소화가 된다. 그러나 이러한 다송운전이 빈번할 때 일반전동기로서는 신뢰도가 문제가 되므로, 이 용도에 적합한 특성을 가지는 운동기를 개정함으로서 신뢰도가 높도록 해야 한다. 이런 종류의 용도로 사용되는 용형전동기로서는 특성상 기동 Torque, 가속 Torque가 크고 단시간에 기동하며 Plugging에 적합하고 Dynamic Brake에도 지장이 없어야 하며, 온도상승의 점에서는 기동중에 1차동손이 적고 2차고저항인것이 요구된다. 또 구조상에서는 Inertia가 작으며 급속한 기동이 제일 먼저 요구된다. 만약 기동중에 발열하는 부분의 열용량이 크며 부하 Inertia도 커서 기동시간이 수10초를 걸린다면 국부적으로 대단히 높은 온도상승을 하게 되고, 가혹한 Plugging운전을 하는 경우는 열적 및 기계적으로 고도의 신뢰성이 요구된다. 이에 적합한 Cycle Starting Motor를 시작하여 본 결과를 경험을 토대로 다목적으로 연구검토하여 여기에 소개하고자 한다.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.165-167
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• 2001

This paper presents a study on successive approximation measurement of mechanical parameters for motor control system. At the first step of servo system installation, control system gain tuning is troublesome work. Recently, auto-tuning method of motion controller for motor drive system is based on parameter measurement and identification. On the case of first order mechanical system (mechanical parameters are modified by simple inertia and friction), it is necessary for good response to get the accurate measurement or identification of the mechanical parameters. In this paper, novel method applies the binary successive approximation measurement to the inertia and friction coefficient. Computer simulation and experiment for the proposed method will show verification of accuracy and usefulness.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.1096-1103
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• 2014

This paper proposes a novel strategy for attenuating the output power fluctuation of the wind farm (WF) in a range of tens of seconds delivered to the grid, where the kinetic energy caused by the large inertia of the wind turbine systems is utilized. A control scheme of the two-level structure is applied to control the wind farm, which consists of a supervisory control of the wind farm and individual wind turbine controls. The supervisory control generates the output power reference of the wind farm, which is filtered out from the available power extracted from the wind by a low-pass filter (LPF). A lead-lag compensator is used for compensating for the phase delay of the output power reference compared with the available power. By this control strategy, when the reference power is lower than the maximum available power, some of individual wind turbines are operated in the storing mode of the kinetic energy by increasing the turbine speeds. Then, these individual wind turbines release the kinetic power by reducing the turbine speed, when the power command is higher than the available power. In addition, the pitch angle control systems of the wind turbines are also employed to limit the turbine speed not higher than the limitation value during the storing mode of kinetic energy. For coordinating the de-rated operation of the WT and the storing or releasing modes of the kinetic energy, the output power fluctuations are reduced by about 20%. The PSCAD/EMTDC simulations have been carried out for a 10-MW wind farm equipped with the permanent-magnet synchronous generator (PMSG) to verify the validity of the proposed method.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.18-20
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• 2004

An interior permanent magnet synchronous motor (IPMSM) is receiving increased attention for many industrial applications because of its high torque to inertia ratio, superior power density, and high efficiency. IPMSM is necessary to use the accurate information of the inductace for the precise torque control owing to the reluctance torque. This paper presents two method to measure the each-axis inductance. The first method uses the peak current that is measured by applying the pulsewise voltage on the each position of IPMSM. The second uses the hysteresis loop of the flux and current measured by applying the positive and negative pulsewise voltage alternately on the each-axis.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.777-780
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• 1991

The practical implementation of model reference adaptive systems(MRAS) using digital computer requires the derivation of discrete-time adaptation laws. This is specially important in the case of direct driver robot and light weight manipulator where inertia changes ang gravity effects are significant. We develope a discrete-time model reference adaptive control scheme for trajectory tracking of robot manipulator. Instead of the conventional Lyapunov approach hyperstabillty theory is more appealing than the Lyapunov approach. It is better suited to discrete time systems and offers more flexibility in design by providing additional free design parameters.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.294-297
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• 1994

A robust position tracking controller of the BLDDM sensitive to the load torque disturbance and inertia variation is constructed It is consisted of the linear feedback controller and the nonlinear feedforward compensator using the neural network. With effietive feedforward compensation of neural network, the robust position control can be obtained, which is verified by computer simulations.

• KIEE International Transactions on Power Engineering
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• v.4A no.3
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• pp.134-140
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• 2004

This paper presents an improved group of energy functions reflecting generator damping effects for multi-machine power systems by using Center of Inertia (COI) formulation as an extension of the previous work. Since rotor angles at the Stable Equilibrium Point (SEP) of post-fault systems are generally calculated in COI, system transient energy can be found without assumption of infinite or slack bus, which is a crucial drawback of the absolute rotor angle frame approach. The developed energy functions have a structure preserving property with which it is very flexible to incorporate various models of power system components, especially various load and generator models. The proposed damping-reflected energy functions are applied to the Potential Energy Boundary Surface (PEBS) method, one of the direct methods. Numerical simulation of WSCC 9-bus shows that conservativeness of the PEBS method can be considerably reduced.