EPE Association: EPE 2005 - Topic 14-5c - DS: Variable speed wind turbine and high power applications

EPE 2005 - Topic 14-5c - DS: Variable speed wind turbine and high power applications
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 14: POWER ELECTRONICS IN ELECTRICAL ENERGY GENERATING SYSTEMS > EPE 2005 - Topic 14-5c - DS: Variable speed wind turbine and high power applications

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   CAGE INDUCTION GENERATORS FOR WIND TURBINES WITH POWER ELECTRONICS CONVERTERS IN THE LIGHT OF THE NEW GRID CODES
By MOLINAS Marta; UNDELAND Tore; NAESS Bjarne; GULVIK William [View]
[Download]

Abstract: An electrical system for wind turbines using cage induction generator with back to back converters for connection to the network is experimentally tested under short circuit conditions in a 55 kW generator set-up. 50\% voltage sag is realized in the laboratory set-up to investigate the performance of the power electronic converters control under the newly introduced grid codes. Standard vector control techniques are implemented with the aim to maintain balance between generated power and power supplied to the grid. The robustness of the power electronics converter is experimentally analyzed under the short circuit for different settings of the converter nominal current and the converters are found to be robust against voltage sags.

   Crowbar Control Algorithms for Doubly Fed Induction Generator During Voltage Dips
By SARASOLA Izaskun; RODRIGUEZ Miguel; GILABERT Alex; ABAD Gonzalo [View]
[Download]

Abstract: The paper presents different control strategies of the crowbar protection when a variable speed wind turbine based on a doubly fed induction machine is generating electrical energy during a voltage dip in the grid.The proposed control strategies provide the wind generator with the capacity for don’t disconnect from the grid while a voltage dip occurs, and return to the normal operation conditions. This will be achieved by a protection circuit called crowbar.In addition, complementary control algorithms for flux damping and voltage recovery will be proposed.Finally, the presented control strategies will be validated in simulation for a 1700KW generator.

   Doubly-Fed Induction Machine as Generator in Wind Power Plant: Nonlinear Control Algorithms with Direct Decoupling
By DITTRICH Andreas; QUANG Nguyen Phung [View]
[Download]

Abstract: Currently the doubly fed induction machine (DFIM) is often used in windpower plants. The digital rotor current controller is always based on DFIM models linearized within a sampling period which does not correspond to the nonlinear nature of the DFIM. The paper deals with a nonlinear control scheme with direct decoupling and presents some first investigation results. This new controller helps to improve ride-through of the wind turbine during grid faults.

   High-Power Converter Systems for High-Speed Generators
By SCHWARZER Ulrich; DE DONCKER Rik. W. ; SCHROEDER Stefan; MEYER Christoph; KOELLENSPERGER Peter [View]
[Download]

Abstract: For grid connection of high-speed gas-turbines, converters can be used to eliminate the otherwise mandatory gearbox. Compared to standard drives, different requirements are imposed on the converter. In this paper, the application of different converter types for a typical gas-turbine generator system are investigated. After selecting suitable topologies and devices, the expected system power losses are calculated using a simulation tool that comprises measured power dissipation for the semiconductors. The loss calculations are done separately for the generator and the grid side converter. Finally, the results are compared and assessed.

   Multi-Level Converter Power Unit
By RAFFEL Holger; ORLIK Bernd; PETTER Thorsten [View]
[Download]

Abstract: The multi-level converter power unit presented here offers the possibility to feed energy into the grid, even standing alone and supplying an isolated grid. Thus, the power unit works according to a novel “Plug and Generate” principle. This is possible because of the self-synchronization of the units to the frequency of the existing electricity grid. So it is possible to have an isolated grid supplied by two independent power units. By using multi-level converters instead of 2-level converters a better power quality can be achieved. In addition, it is possible to supply asymmetrical grids or consumers. In the case of an asymmetrical load, a symmetrical three-phase voltage can be made available by such a “power unit”.

   Novel High Power IGBT Inverter for a Power Conditioning System
By ZINGEL Reinhard; NAHRSTAEDT Manfred [View]
[Download]

Abstract: The paper describes the features of a novel watercooled 690 V high power IGBT inverter design using polypropylene film capacitors in the dc link instead of electrolytic capacitors. The first application is a Power Conditioning System (PCS) with an output of ±9600 kvar to control the reactive power of a 90 MW windfarm in New Zealand steplessly and to feed capacitive current instantaneously into a voltage dip disturbed power supply. Due to its 4-quadrant ability, the PCS is equally well suited for dynamic control of battery energy storage systems.

   Voltage dips compensation by wind farm(s) equipped with power converters as decoupling element
By HEIER Siegfried; SAIJU Rajesh; ARNOLD Gunter [View]
[Download]

Abstract: The percentage of the variation of the state variables voltage and frequency determines the quality of a grid. In the medium voltage grid , the sudden connection and disconnection of the heavy loads or by power fluctuations of generation units causes voltage dips. During such changes, grid stability can be insured through additional active and reactive power contribution. It is very important to investigate whether wind farm(s) could contribute to improve grid condition through simulation methods. Due to the variation in wind speed, the available power from the wind farm(s) varies also, which supplies fluctuating state variables. It means that direct connection of the wind farm(s) can lead to grid instability. In such circumstances, the decoupling between the state variables of the wind farm(s) and the grid is essential. The application of power converters in WTG makes it possible to decouple the WTG speed from the grid frequency. At the same time, the state variables can be independently controlled. This paper presents the voltage dips compensation by wind farm(s) equipped with power converters through the models based upon Matlab-Simulink. Many different sizes of the wind farms are formed and simulated with different nature of loads to get an over-all impression.

EPE 2005 - Topic 14-5c - DS: Variable speed wind turbine and high power applications
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 14: POWER ELECTRONICS IN ELECTRICAL ENERGY GENERATING SYSTEMS > EPE 2005 - Topic 14-5c - DS: Variable speed wind turbine and high power applications
	[return to parent folder]

	CAGE INDUCTION GENERATORS FOR WIND TURBINES WITH POWER ELECTRONICS CONVERTERS IN THE LIGHT OF THE NEW GRID CODES By MOLINAS Marta; UNDELAND Tore; NAESS Bjarne; GULVIK William	[View] [Download]
Abstract: An electrical system for wind turbines using cage induction generator with back to back converters for connection to the network is experimentally tested under short circuit conditions in a 55 kW generator set-up. 50\% voltage sag is realized in the laboratory set-up to investigate the performance of the power electronic converters control under the newly introduced grid codes. Standard vector control techniques are implemented with the aim to maintain balance between generated power and power supplied to the grid. The robustness of the power electronics converter is experimentally analyzed under the short circuit for different settings of the converter nominal current and the converters are found to be robust against voltage sags.

	Crowbar Control Algorithms for Doubly Fed Induction Generator During Voltage Dips By SARASOLA Izaskun; RODRIGUEZ Miguel; GILABERT Alex; ABAD Gonzalo	[View] [Download]
Abstract: The paper presents different control strategies of the crowbar protection when a variable speed wind turbine based on a doubly fed induction machine is generating electrical energy during a voltage dip in the grid.The proposed control strategies provide the wind generator with the capacity for don’t disconnect from the grid while a voltage dip occurs, and return to the normal operation conditions. This will be achieved by a protection circuit called crowbar.In addition, complementary control algorithms for flux damping and voltage recovery will be proposed.Finally, the presented control strategies will be validated in simulation for a 1700KW generator.

	Doubly-Fed Induction Machine as Generator in Wind Power Plant: Nonlinear Control Algorithms with Direct Decoupling By DITTRICH Andreas; QUANG Nguyen Phung	[View] [Download]
Abstract: Currently the doubly fed induction machine (DFIM) is often used in windpower plants. The digital rotor current controller is always based on DFIM models linearized within a sampling period which does not correspond to the nonlinear nature of the DFIM. The paper deals with a nonlinear control scheme with direct decoupling and presents some first investigation results. This new controller helps to improve ride-through of the wind turbine during grid faults.

	High-Power Converter Systems for High-Speed Generators By SCHWARZER Ulrich; DE DONCKER Rik. W. ; SCHROEDER Stefan; MEYER Christoph; KOELLENSPERGER Peter	[View] [Download]
Abstract: For grid connection of high-speed gas-turbines, converters can be used to eliminate the otherwise mandatory gearbox. Compared to standard drives, different requirements are imposed on the converter. In this paper, the application of different converter types for a typical gas-turbine generator system are investigated. After selecting suitable topologies and devices, the expected system power losses are calculated using a simulation tool that comprises measured power dissipation for the semiconductors. The loss calculations are done separately for the generator and the grid side converter. Finally, the results are compared and assessed.

	Multi-Level Converter Power Unit By RAFFEL Holger; ORLIK Bernd; PETTER Thorsten	[View] [Download]
Abstract: The multi-level converter power unit presented here offers the possibility to feed energy into the grid, even standing alone and supplying an isolated grid. Thus, the power unit works according to a novel “Plug and Generate” principle. This is possible because of the self-synchronization of the units to the frequency of the existing electricity grid. So it is possible to have an isolated grid supplied by two independent power units. By using multi-level converters instead of 2-level converters a better power quality can be achieved. In addition, it is possible to supply asymmetrical grids or consumers. In the case of an asymmetrical load, a symmetrical three-phase voltage can be made available by such a “power unit”.

	Novel High Power IGBT Inverter for a Power Conditioning System By ZINGEL Reinhard; NAHRSTAEDT Manfred	[View] [Download]
Abstract: The paper describes the features of a novel watercooled 690 V high power IGBT inverter design using polypropylene film capacitors in the dc link instead of electrolytic capacitors. The first application is a Power Conditioning System (PCS) with an output of ±9600 kvar to control the reactive power of a 90 MW windfarm in New Zealand steplessly and to feed capacitive current instantaneously into a voltage dip disturbed power supply. Due to its 4-quadrant ability, the PCS is equally well suited for dynamic control of battery energy storage systems.

	Voltage dips compensation by wind farm(s) equipped with power converters as decoupling element By HEIER Siegfried; SAIJU Rajesh; ARNOLD Gunter	[View] [Download]
Abstract: The percentage of the variation of the state variables voltage and frequency determines the quality of a grid. In the medium voltage grid , the sudden connection and disconnection of the heavy loads or by power fluctuations of generation units causes voltage dips. During such changes, grid stability can be insured through additional active and reactive power contribution. It is very important to investigate whether wind farm(s) could contribute to improve grid condition through simulation methods. Due to the variation in wind speed, the available power from the wind farm(s) varies also, which supplies fluctuating state variables. It means that direct connection of the wind farm(s) can lead to grid instability. In such circumstances, the decoupling between the state variables of the wind farm(s) and the grid is essential. The application of power converters in WTG makes it possible to decouple the WTG speed from the grid frequency. At the same time, the state variables can be independently controlled. This paper presents the voltage dips compensation by wind farm(s) equipped with power converters through the models based upon Matlab-Simulink. Many different sizes of the wind farms are formed and simulated with different nature of loads to get an over-all impression.