EPE Association: NORpie 2004 - Topic 05: Wind Generators

NORpie 2004 - Topic 05: Wind Generators
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   Basic Operation Principles and Electrical Conversion Systems of Wind Turbines
By H. Polinder; S.W.H. de Haan; M. R. Dubois; J. G. Slootweg [View]
[Download]

Abstract: This paper gives an overview of electrical conversion systems for wind turbines. First, the basics of wind energy conversion with wind turbines are reviewed and requirements with respect to the electric system are considered. Next, the three classical conversion systems are described with their strengths and weaknesses: constant speed, variable speed with doubly-fed induction generator and variable speed with direct-drive generator. The applied electric converters are shortly addressed. Finally, alternative generator systems and trends are discussed. There is a clear trend towards variable speed systems. Doubly-fed induction generator systems are increasingly equipped with grid fault ride through capabilities. For direct-drive turbines, the radial flux permanent-magnet synchronous generator is cheaper and more efficient than the electrically excited synchronous generator. It is expected that the voltage level of generators will increase up to values in the order of 5 kV.

   Rotating and Linear Synchronous Generators for Renewable Electric Energy Conversion - an Update of the Ongoing Research Projects at Uppsala University
By B.Bolund; E.Segergren; A.Solum; R. Perers; L. Lundström; A. Lindblom; K. Thorburn; M. Eriksson; K. Nilsson; I. Ivanova; O. Danielsson; S. Eriksson; H. Bengtsson [View]
[Download]

Abstract: The discussion regarding renewable energy has gone on for several years. The many ideas and opinions that are presented in this field reflect the great impact future energy production has on people all over the world. This paper describes the new direction of the division of Electricity at Uppsala University after the admission of the new professor, Mats Leijon, in February 2001. Full electromagnetic dynamics can be used in order to improve performance of existing electromagnetic conversion systems and to adapt new technology to the renewable power in nature. These ideas are adopted in wind power, wave power, water-current power, bio-fuelled plants as well as in conventional hydropower, i.e. in every different area were the division is active. This paper is a coarse description of the different activities at the division and aims to highlight their link to each other. Theoretical and experimental results from the different PhD projects are briefly introduced and summarized.

   Voltage Regulator for Reactive Power Control on Synchronous Generators in Wind Energy Power Plants
By B. Rabelo; W. Hofmann; M. Tilscher; A. Basteck [View]
[Download]

Abstract: This paper presents a voltage regulator for the field circuit of a separately excited synchronous generator in wind power plants. A hydrodynamic variable speed planetary gear is used to maintain constant speed on the generator shaft. The generator is directly connected to the net without power electronics . This new concept promises better power quality and do not need bulky output filters. In order to fulfil new requirements on wind generation units the field voltage controller must present some features like reactive power and dynamical stability control. The used model and the design procedures, as well as some simulation results are shown

   Design of the Zephyros Z72 wind turbine with emphasis on the direct drive PM generator
By C. J. A. Versteegh [View]
[Download]

Abstract: The Zephyros Z72 is a gearless variable speed wind turbine with a direct driven PM synchronous generator with a rotor diameter of 70 m. This article describes the design process, testing and prototyping with focus on the generator which till date is the biggest PM generator available on the wind turbine market. The turbine after testing and commissioning has a track record of over 8000 grid connected hours and more than 4700 MWh produced. Tests and operational experience is commented and results are given. Measurements such as the power curve (power versus average wind speed), noise and heat run have been performed and show good results and reassembly with the design calculations. The turbine has been installed in April 2002 and certification design assessment and measurements are completed.

   Study of TFPM machines with toothed rotor applied to direct-drive generators for wind turbines
By M.R. Dubois [View]
[Download]

Abstract: Today, the combination gearbox-medium-speed (1000-2000 rpm) induction generator dominates the market of MW-scale wind turbines. This is due to the lower costs of the gearbox option compared to the costs of gearless systems. Various Transverse-Flux Permanent Magnet (TFPM) machine topologies are investigated for cost reduction.TFPM machines with toothed rotor are compared with the conventional PM synchronous machines based on their optimized cost/torque. The TFPM machine with toothed rotor obtains lower cost/torque for diameters of 0.5 m and 1.0 m. At diameters larger than 1.0 m, the conventional PM synchronous machine obtains lower cost/torque.

NORpie 2004 - Topic 05: Wind Generators
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2004 > NORpie 2004 - Topic 05: Wind Generators
	[return to parent folder]

	Basic Operation Principles and Electrical Conversion Systems of Wind Turbines By H. Polinder; S.W.H. de Haan; M. R. Dubois; J. G. Slootweg	[View] [Download]
Abstract: This paper gives an overview of electrical conversion systems for wind turbines. First, the basics of wind energy conversion with wind turbines are reviewed and requirements with respect to the electric system are considered. Next, the three classical conversion systems are described with their strengths and weaknesses: constant speed, variable speed with doubly-fed induction generator and variable speed with direct-drive generator. The applied electric converters are shortly addressed. Finally, alternative generator systems and trends are discussed. There is a clear trend towards variable speed systems. Doubly-fed induction generator systems are increasingly equipped with grid fault ride through capabilities. For direct-drive turbines, the radial flux permanent-magnet synchronous generator is cheaper and more efficient than the electrically excited synchronous generator. It is expected that the voltage level of generators will increase up to values in the order of 5 kV.

	Rotating and Linear Synchronous Generators for Renewable Electric Energy Conversion - an Update of the Ongoing Research Projects at Uppsala University By B.Bolund; E.Segergren; A.Solum; R. Perers; L. Lundström; A. Lindblom; K. Thorburn; M. Eriksson; K. Nilsson; I. Ivanova; O. Danielsson; S. Eriksson; H. Bengtsson	[View] [Download]
Abstract: The discussion regarding renewable energy has gone on for several years. The many ideas and opinions that are presented in this field reflect the great impact future energy production has on people all over the world. This paper describes the new direction of the division of Electricity at Uppsala University after the admission of the new professor, Mats Leijon, in February 2001. Full electromagnetic dynamics can be used in order to improve performance of existing electromagnetic conversion systems and to adapt new technology to the renewable power in nature. These ideas are adopted in wind power, wave power, water-current power, bio-fuelled plants as well as in conventional hydropower, i.e. in every different area were the division is active. This paper is a coarse description of the different activities at the division and aims to highlight their link to each other. Theoretical and experimental results from the different PhD projects are briefly introduced and summarized.

	Voltage Regulator for Reactive Power Control on Synchronous Generators in Wind Energy Power Plants By B. Rabelo; W. Hofmann; M. Tilscher; A. Basteck	[View] [Download]
Abstract: This paper presents a voltage regulator for the field circuit of a separately excited synchronous generator in wind power plants. A hydrodynamic variable speed planetary gear is used to maintain constant speed on the generator shaft. The generator is directly connected to the net without power electronics . This new concept promises better power quality and do not need bulky output filters. In order to fulfil new requirements on wind generation units the field voltage controller must present some features like reactive power and dynamical stability control. The used model and the design procedures, as well as some simulation results are shown

	Design of the Zephyros Z72 wind turbine with emphasis on the direct drive PM generator By C. J. A. Versteegh	[View] [Download]
Abstract: The Zephyros Z72 is a gearless variable speed wind turbine with a direct driven PM synchronous generator with a rotor diameter of 70 m. This article describes the design process, testing and prototyping with focus on the generator which till date is the biggest PM generator available on the wind turbine market. The turbine after testing and commissioning has a track record of over 8000 grid connected hours and more than 4700 MWh produced. Tests and operational experience is commented and results are given. Measurements such as the power curve (power versus average wind speed), noise and heat run have been performed and show good results and reassembly with the design calculations. The turbine has been installed in April 2002 and certification design assessment and measurements are completed.

	Study of TFPM machines with toothed rotor applied to direct-drive generators for wind turbines By M.R. Dubois	[View] [Download]
Abstract: Today, the combination gearbox-medium-speed (1000-2000 rpm) induction generator dominates the market of MW-scale wind turbines. This is due to the lower costs of the gearbox option compared to the costs of gearless systems. Various Transverse-Flux Permanent Magnet (TFPM) machine topologies are investigated for cost reduction.TFPM machines with toothed rotor are compared with the conventional PM synchronous machines based on their optimized cost/torque. The TFPM machine with toothed rotor obtains lower cost/torque for diameters of 0.5 m and 1.0 m. At diameters larger than 1.0 m, the conventional PM synchronous machine obtains lower cost/torque.