• Journal of Power Electronics
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• 제16권6호
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• pp.2294-2305
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• 2016

The introduction of a high-voltage direct-current (HVDC) system based on a modular multilevel converter (MMC) for wind farm integration has stimulated studies on methods to control this type of converter. This research article focuses on the control of the AC voltage and circulating current for a wind-farm-side MMC (WFS-MMC). After theoretical analysis, emotional learning (EL) controllers are proposed for the controls. The EL controllers are derived from the learning mechanisms of the amygdala and orbitofrontal cortex which make the WFS-MMC insensitive to variance in system parameters, power change, and fault in the grid. The d-axis and q-axis currents are respectively considered for the d-axis and q-axis voltage controls to improve the performance of AC voltage control. The practicability of the proposed control is verified under various conditions with a point-to-point MMC-HVDC system. Simulation results show that the proposed method is superior to the traditional proportional-integral controller.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.361-362
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• 2015

This paper proposes a Direct Power Control (DPC) scheme of improved command tracking capability for Permanent Magnet Synchronous Generator (PMSG) Medium Voltage (MV) Wind Turbines. Benchmarking is performed based on a neutral point clamped three-level back-to-back type voltage source converter. It is introduced to design the DPC modeling and propose DPC scheme of a three-level NPC (3L-NPC) converter. During the fault condition in wind farms, the proposed control scheme directly controls the generated output power to the command value from the hierarchical wind farm controller. The proposed control scheme is compared with conventional control scheme as respect to loss and thermal analysis. The DPC scheme of improved command tracking capability is confirmed through PLECS simulations. Simulation result shows that proposed control scheme achieves a much shorter transient time in a step response of generated output power. The proposed control scheme makes it possible to provide a good dynamic performance for PMSG MV wind turbine to generate a high quality output power under grid fault condition.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.173-174
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• 2016

This paper proposes a comparison of Voltage Oriented Control (VOC) and Direct Power Control (DPC) under command mode transition for PMSG Wind Turbines (WT). Based on a neutral point clamped three level back to back type Voltage Source Converter (VSC), proposed control scheme automatically control the generated output power to satisfy a grid requirement from the hierarchical wind farm controller. Automatic command mode transition based on the dc-link voltage error provides a command mode changing between grid command and MPPT mode. It is confirmed through PLECS simulations in Matlab. Simulation result shows that proposed control scheme of VOC and DPC achieves a much shorter transient time of generated output power than the conventional control scheme of MPPT with optimal torque control and VOC under a step response. The proposed control scheme makes it possible to provide a good dynamic performance for PMSG wind turbines in order to generate a high quality output power.

• 한국태양에너지학회 논문집
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• 제33권6호
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• pp.70-76
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• 2013

Recently industrial control systems have been required to ensure intelligent, high tech automation, interconnection and interoperability demands. Therefore, there is a need to redefine the structure concepts of SCADA system for wind power. Also, at this time, the integrated management system is required for the distributed development of wind farms where are needed often interoperability features and exchange information between different wind farms, wind turbines or SCADA systems. In this paper, an integrated structural concepts for SCADA system are defined. Based on this definition of an integrated SCADA system, the basic designs are analyzed on physical layer, system layer and application layer which are corresponded to wind turbine controller, the SCADA server and the SCADA client, and implement HMI. Between the implementation SCADA server and the client, their normal functions were verified at the small scale wind energy test facilities.

• 전력전자학회논문지
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• 제21권3호
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• pp.238-248
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• 2016

In this study, an automatic command mode transition strategy of direct power control (DPC) is proposed for permanent magnet synchronous generators (PMSGs) medium-voltage (MV) offshore wind turbines (WTs). Benchmarking against the control methods are performed based on a three-level neutral-point-clamped (NPC) back-to-back type voltage source converter (VSC). The ramping rate criterion of complex power is utilized to select the switching vector in DPC for a three-level NPC converter. With a grid command and an MPPT mode transition strategy, the proposed control method automatically controls the generated output power to satisfy a grid requirement from the hierarchical wind farm controller. The automatic command mode transition strategy of DPC is confirmed through PLECS simulations based on Matlab. The simulation result of the automatic mode transition strategy shows that the proposed control method of VOC and DPC achieves a much shorter transient time of generated output power than the conventional control methods of MPPT and VOC under a step response. The proposed control method helps provide a good dynamic performance for PMSGs MV offshore WTs, thereby generating high quality output power.