EPE Association: NORpie 2006 - Topic 10: Wind Power

NORpie 2006 - Topic 10: Wind Power
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2006 > NORpie 2006 - Topic 10: Wind Power

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   Energy efficiency for DC/DC converters in a DC grid system for wind farms
By L. Max [View]
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Abstract: In this paper the suitability of three DC/DC converters for a DC wind park grid is investigated from an energy efficiency point of view. The three selected topologies are the fullbridge converter, the single active bridge converter and the series parallel resonant converter. The energy efficiency of the three converter types are evaluated for the wide range of operating conditions that occur in a wind park. It was found that the resonant converter has the lowest losses of the three types and the fullbridge converter was found to be second best. Moreover, it is shown that the variable operating conditions creates problems for all three converters, especially at low power. The single active bridge converter is most affected by the wide range of operation since it is forced to operate in discontinuous conduction mode in all cases which generates high losses. The resonant converter has low losses, but the peak voltage at the transformer is up to twice the input voltage.

   Voltage dips compensation in Wind Farms using Dynamic Voltage Restorer
By C. Alvarez; H. Amaris [View]
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Abstract: In the last years, the amount of installed wind power has continued to increase. Although technological advances have allowed this increase, there are other challenges needing to be solved in the future. A critical factor is the fault ride-through capability of wind turbines under fault conditions. In this paper Dynamic Voltage Restorer (DVR) is used for compensating voltage dips occurring at Wind farms. The control strategies are presented and the performance is shown under different fault situations by simulations.

   Power Flow Control Technologies for Wind Power
By M. Molinas; L. Gertmar; T. Undeland [View]
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Abstract: In this paper several different technologies based on power electronics only and on electromechanical devices combined with power electronics for power flow control in tielines are presented. More specifically, Flexible AC Transmission Systems (FACTS) power flow controllers and the Rotary Phase Shifter (RPS) are discussed and their control capabilities are evaluated. These solutions are proposed for an environment in which wind power takes part of the power transfer through an interconnection between two regions. Measurements for the RPS and a discussion for the FACTS devices are presented.

   Dynamic Operation and Energy Gain of a Wind Power Station with Converter Fed Permanent Magnet Synchronous Machine
By S. Jensen; F. W. Fuchs [View]
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Abstract: Object of this theoretical investigation is the electrical power fed in by a wind power station. How much of that power can be fed into the grid by wind power station depends on aspects of their mechanical and electrical design. By a simple point of view and towards economic interests, the maximum possible power should be fed into the grid. As a result, high transient load to the grid is done. Furthermore, mechanical limitations lead to the solution, that a moderate extraction of the power of the wind should rather be considered.
For this reason, the results of a theoretical analysis of the dynamic network related performance of transmitted power with respect to the mechanical conditions and the influence of control parameters to its transient and steady state operation characteristics are presented. The electromechanical conversion system consists of a permanent magnet synchronous machine connected to a voltage source converter. The drive setup has been simulated using maximum power control which permits active engagement to the performance of the actuation.

   A Complete Order Model Dynamic Simulation of a Stand-Alone Doubly-Fed Induction Generator
By S. Zaki Farooqui; O. Carlson [View]
[Download]

Abstract: A numerical method has been suggested and applied to simulate the operation of a stand alone Doubly-Fed Induction Generator, in a wide range of sub and super synchronous operating speeds. The stand alone operation is achieved through vector control, by imposing the alignment of the d-axis of the synchronously rotating reference frame along the stator flux vector. Twenty seconds simulations are presented by feeding the stator d and q current components, and artificially generated wind speed. For the sake of demonstration of the operation in all speed ranges, the input current components have been drawn from the simulation of a rotor short circuited, grid connected DFIG, starting from rest. The synchronous frequency s, and stator voltages Vds ref and Vqs ref are imposed as constant demands in the control equations. Simulations are carried out by independently iteratively solving three differential equations for magnetizing current Ims, and rotor current components Idr and Iqr, respectively. Solutions of these equations respectively generate the demands for the rotor current Idr, and rotor voltage components Vdr and Vqr. The demand for Iqr is obtained directly from the field alignment condition. The stator current input data includes a 150 millisecond fault induction response to a stator voltage step change from 1 to 0.5 per unit.

NORpie 2006 - Topic 10: Wind Power
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2006 > NORpie 2006 - Topic 10: Wind Power
	[return to parent folder]

	Energy efficiency for DC/DC converters in a DC grid system for wind farms By L. Max	[View] [Download]
Abstract: In this paper the suitability of three DC/DC converters for a DC wind park grid is investigated from an energy efficiency point of view. The three selected topologies are the fullbridge converter, the single active bridge converter and the series parallel resonant converter. The energy efficiency of the three converter types are evaluated for the wide range of operating conditions that occur in a wind park. It was found that the resonant converter has the lowest losses of the three types and the fullbridge converter was found to be second best. Moreover, it is shown that the variable operating conditions creates problems for all three converters, especially at low power. The single active bridge converter is most affected by the wide range of operation since it is forced to operate in discontinuous conduction mode in all cases which generates high losses. The resonant converter has low losses, but the peak voltage at the transformer is up to twice the input voltage.

	Voltage dips compensation in Wind Farms using Dynamic Voltage Restorer By C. Alvarez; H. Amaris	[View] [Download]
Abstract: In the last years, the amount of installed wind power has continued to increase. Although technological advances have allowed this increase, there are other challenges needing to be solved in the future. A critical factor is the fault ride-through capability of wind turbines under fault conditions. In this paper Dynamic Voltage Restorer (DVR) is used for compensating voltage dips occurring at Wind farms. The control strategies are presented and the performance is shown under different fault situations by simulations.

	Power Flow Control Technologies for Wind Power By M. Molinas; L. Gertmar; T. Undeland	[View] [Download]
Abstract: In this paper several different technologies based on power electronics only and on electromechanical devices combined with power electronics for power flow control in tielines are presented. More specifically, Flexible AC Transmission Systems (FACTS) power flow controllers and the Rotary Phase Shifter (RPS) are discussed and their control capabilities are evaluated. These solutions are proposed for an environment in which wind power takes part of the power transfer through an interconnection between two regions. Measurements for the RPS and a discussion for the FACTS devices are presented.

	Dynamic Operation and Energy Gain of a Wind Power Station with Converter Fed Permanent Magnet Synchronous Machine By S. Jensen; F. W. Fuchs	[View] [Download]
Abstract: Object of this theoretical investigation is the electrical power fed in by a wind power station. How much of that power can be fed into the grid by wind power station depends on aspects of their mechanical and electrical design. By a simple point of view and towards economic interests, the maximum possible power should be fed into the grid. As a result, high transient load to the grid is done. Furthermore, mechanical limitations lead to the solution, that a moderate extraction of the power of the wind should rather be considered. For this reason, the results of a theoretical analysis of the dynamic network related performance of transmitted power with respect to the mechanical conditions and the influence of control parameters to its transient and steady state operation characteristics are presented. The electromechanical conversion system consists of a permanent magnet synchronous machine connected to a voltage source converter. The drive setup has been simulated using maximum power control which permits active engagement to the performance of the actuation.

	A Complete Order Model Dynamic Simulation of a Stand-Alone Doubly-Fed Induction Generator By S. Zaki Farooqui; O. Carlson	[View] [Download]
Abstract: A numerical method has been suggested and applied to simulate the operation of a stand alone Doubly-Fed Induction Generator, in a wide range of sub and super synchronous operating speeds. The stand alone operation is achieved through vector control, by imposing the alignment of the d-axis of the synchronously rotating reference frame along the stator flux vector. Twenty seconds simulations are presented by feeding the stator d and q current components, and artificially generated wind speed. For the sake of demonstration of the operation in all speed ranges, the input current components have been drawn from the simulation of a rotor short circuited, grid connected DFIG, starting from rest. The synchronous frequency s, and stator voltages Vds ref and Vqs ref are imposed as constant demands in the control equations. Simulations are carried out by independently iteratively solving three differential equations for magnetizing current Ims, and rotor current components Idr and Iqr, respectively. Solutions of these equations respectively generate the demands for the rotor current Idr, and rotor voltage components Vdr and Vqr. The demand for Iqr is obtained directly from the field alignment condition. The stator current input data includes a 150 millisecond fault induction response to a stator voltage step change from 1 to 0.5 per unit.