EPE Association: EPE 2009 - Topic 14-10 - DS: 'Wind and Ocean Power Generator Systems'

EPE 2009 - Topic 14-10 - DS: 'Wind and Ocean Power Generator Systems'
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2009 - Conference > EPE 2009 - Topic 14: 'Electrical Energy Generating Systems, Renewable Energy Systems' > EPE 2009 - Topic 14-10 - DS: 'Wind and Ocean Power Generator Systems'

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   A Micro Wind Power Generation System Using Permanent Magnet Reluctance Generator
By Hiroki GOTO, Hai-Jiao GUO, Osamu ICHINOKURA [View]
[Download]

Abstract: Permanent magnet reluctance generator (PMRG) has robust construction similar to switched reluctance generator (SRG), but PMRG requires no excitation unlike SRG. So, PMRG is suitable for a micro wind generation system because of its low cost on manufacturing and its simple control circuit. In the paper, a 250-watt micro wind power generation system using PMRG is proposed. First, a new magnetic circuit model of the PMRG is proposed and simulated dynamically with the power converter by a general-purpose circuit simulator. It is confirmed that the proposed model is acceptable by comparing with calculation results of finite element analysis (FEM). Second, the proposed micro wind generation system is totally simulated using the magnetic circuit model of the PMRG with power converters, maximum power tracking control scheme, and power smoothing system using electric double layer capacitor(EDLC). Finally, experimental results by a simulated wind turbine are presented. The proposed wind generation system employed with PMRG contributes to expand into low cost wind generation.

   A Modified Vector Control Strategy for DFIG Based Wind Turbines to Ride-through Voltage Dips
By Ling PENG, FrÃ©dÃ©ric COLAS, Bruno FRANCOIS, Yongdong LI [View]
[Download]

Abstract: Nowadays, the wind market is dominated by doubly fed induction generator (DFIG) based wind turbines. However, they are very sensitive to grid faults due to the small rated power converters and direct connection to the grid. In order to improve its Low Voltage Ride-Through (LVRT) capability, this paper proposes a modified vector control strategy of the DFIG by considering the dynamics of stator flux deduced by grid voltage dip. The limitation of the proposed scheme is also presented with a feasible region, which indicates the necessity of additional protection implementation such as crowbar. Then coordinated control strategies are proposed to enhance the LVRT performance with grid voltage support capability. Simulation results show the effectiveness of the proposed control schemes.

   Analysis of Three-phase Short Circuit Current of DFIG
By Xueguang ZHANG, Rui LI, Dianguo XU [View]
[Download]

Abstract: The paper analyzes the theory of generating short circuit current during three-phase fault to research the low voltage ride through (LVRT) control of doubly fed induction generator (DFIG). The approximate analytical expressions of short circuit current are given in the condition of no load and synchronous speed to simplify the analysis. Based on this, the influences of different pre-fault conditions, such as reactive power, active power and speed, on short circuit current of DFIG are studied. At last, a 3MW DFIG model is built and the simulation is done to validate the theory analysis.

   Design of Power Converter driving a Linear Generator for Wave Energy Applications
By Marcos BLANCO, gustavo NAVARRO, Marcos LAFOZ [View]
[Download]

Abstract: This paper describes aspects of the power electronics control of wave energy conversion. The objective of the power converter is to drive a switched reluctance linear machine which works as direct-drive power take off (DDPTO) system for a point absorber. FEM analysis and simulations of the electrical machine were taken into account in the design of the converter control strategy. Finally, laboratory testing will be described in the paper.

   DFIG based standalone power system operating at low load conditions.
By Grzegorz IWANSKI [View]
[Download]

Abstract: The comparison of inductive and capacitive filter for standalone variable speed operated doubly fed induction generator DFIG is presented in the paper. Simulation and experimental results of both methods of filtration are shown. The model equations with stator connected filtering capacitors are analyzed. Sensorless control of the stator voltage vector in the polar frame is described. PLL based frequency control of generated stator voltage is presented. Modification of the control system allow for faster synchronization of the actual and reference voltage vector, what provide shorter start-up procedure of the system and better stabilization especially at low load conditions. Simulation and experimental results of improved frequency control of the standalone doubly fed induction generator are presented.

   High efficiency field oriented control of an induction generator for a tidal current turbine
By Salvatore DE CARO, Antonio TESTA, Tommaso SCIMONE [View]
[Download]

Abstract: The paper discusses potential advantages in using an efficiency optimized field orientation strategy to control a variable speed induction generator exploiting the energy of tidal currents. The rotor flux of the induction generator is managed in order to minimize the total losses according to an off-line efficiency optimization strategy. The evaluation of potential advantages in using the efficiency optimized field orientation technique is carried out by experimental tests performed on a scale model and by simulations of a 18 kW induction generator prototype. Obtained results show that an encouraging 11\% increment of the produced energy can be obtained without additional costs.

   Investigations on Energy Yield and Power Fluctuation from Different Control Methods for Wind Energy Converters at Various Wind Conditions
By Bingchang NI, Constantinos SOURKOUNIS [View]
[Download]

Abstract: The share of electricity generated by wind power converters is world wide steadily growing. With increasing shares of wind energy in the electrical power supply, their influence on the mains stability and their reliable energy contribution will become more relevant. Especially at points of common coupling of weak grid branches fluctuating power output of wind energy converters can be harmful for the grid stability. The system management of wind energy converters has great influence on the power yield and the damping/amplification of wind caused power fluctuations. This paper compares a new control approach, the Stochastic Dynamic Optimization, with common control methods, regarding their power yield and electrical power output fluctuation for different wind conditions. The results show that the Stochastic Dynamic Optimization control approach has superior performance regarding the power yield and low power output fluctuation.

   Management of Power Excess in Wind Turbine Systems
By natalia angela ORLANDO, marco LISERRE, antonio DELL'AQUILA [View]
[Download]

Abstract: Variable speed wind turbine generators provide the opportunity to capture more power than fixed speed turbines. However also the limitation of the produced power is an important issue. The paper is focused on the management of the power in excess in a variable-speed wind turbine equipped with a PMSG (Permanent Magnet Synchronous Generator) connected to the grid through a back-to-back converter. It is investigated the role of the braking chopper to dissipate the power in excess that can not be injected in the grid and the blade pitch control to limit the aerodynamic power in above-rated wind speeds in order to keep the turbine within its design limits. The interaction between the blade pitch control and the braking chopper is discussed. Finally, some simulation results in the case of a ramping wind speed and under real wind conditions are reported.

   Maximum Power Tracking of Wind Power Generation System with Inverter Excited Induction Machine
By Noriyuki KIMURA, Tomoyuki HAMADA, Makoto SONODA, Kenichi NAKATANI, toshimitsu MORIZANE, Katsunori TANIGUCHI, Yasuyuki NISHIDA [View]
[Download]

Abstract: This paper shows a new induction generation system for wind power generation. This system has the voltage source converter exciting induction generator and the PFC converter to transfer the real power. This configuration enables asynchronous link and maximum power tracking for the cage rotor induction generator. Usually two full rating inverter sets are necessary to construct the asynchronous link. Proposed system uses an inverter of small rating, 10\% of full rating, and a PFC converter can replace the roll of the real power transfer at the generator side. This configuration can reduce the total system costs. This paper has investigated the maximum power point tracking control of the proposed system by simulation. The simulation results show the good tracking ability and certify the reduction of the inverter rating at the generator side.

   Modelling and Control in Wind Energy Conversion Systems (WECS)
By Luis GONZALEZ [View]
[Download]

Abstract: This paper encompasses the study of modelling and design of WECS, using a wind turbine with known dynamic characteristics and a permanent magnet synchronous generator driven by a back to back power converter topology. The dynamic modeling allows to know the response of the turbine generator system in the whole range of operation. In this study, it is proposed a variable structure control scheme with two different kind of operation, namely Maximum Power Point Tracking (MPPT) and Constant Power (CP). In the CP region, it is demonstrated that the system is controllable with the speed control loop while that using torque control an unstable control loop results.

   New Design Control Dedicated To Low Voltage Ride Through of Hybrid Wind Plant
By Alexandre TENINGE [View]
[Download]

Abstract: In this paper, the low voltage ride-through (LVRT) capabilities of an hybrid wind plant is studied. The hybrid wind plant considered combines fixed speed wind turbines (FSWTs) based on classical induction generator and full power converter variable speed wind turbines (VSWTs) with permanent magnet generator. However, it must be able to respect grid code requirements. A specific control of the variable speed wind turbine power converters is proposed and described in this paper to support FSWTs during voltage dips: the gride side converter is used as a STATCOM during voltage drop to provide the maximum of reactive power. Simulation results show the ability of the wind plant to ride-through a voltage dip with this control.

   Peak Current Mode Control of a Boost Rectifier with Low Distortion of the Input Current for Wind Power Systems based on Permanent Magnet Synchronous Generators
By OSCAR CARRANZA, EMILIO FIGUERES, GABRIEL GARCERA, LUIS GERARDO GONZALEZ, FRAN GONZALEZ-ESPIN [View]
[Download]

Abstract: This paper presents a Peak Current Mode Control of a Boost Rectifier with Low Distortion of the Input Current for Wind Power Systems based on Permanent Magnet Synchronous Generators with variable speed operation. The Three-Phase Boost Rectifier is operated in Discontinuous Conduction Mode (DCM). It is shown that the DCM operation significantly reduces the Total Harmonics Distortion of the currents in the Permanent Magnet Synchronous Generator, increasing the Power Factor of the system, so that the vibrations and mechanical stress of the generator is minimized. The characteristics of the DCM Boost rectifier are studied considering: 1) The series resistance of the inductors; 2) The modeling and adjustment of peak current mode control yielding a stable loop; 3) The design of an input filter that reduces the switching noise in the currents of the generator.

   Reactive Power Analysis and Control of Doubly Fed Induction Generator Wind Farm
By Dianguo XU, Rui LI, Yicheng LIU, Yongqiang LANG [View]
[Download]

Abstract: Power relations of doubly fed induction generator (DFIG) wind power generation system are analyzed. Based on this, a method is proposed to calculate the reactive power limit. Furthermore, the reactive power control of DFIG wind farm is studied and the control scheme is provided to exert the reactive power dealing capability of wind power system. A reactive power compensation strategy for the local user using DFIG wind farm and the distribution algorithms of reactive power demand are given. Simulation results are provided to verify the proposed theory.

   Research Laboratory for Power Electronic Generator Systems in Wind Turbines Comprising Converters, Generators, Interaction and Grid Interaction
By Friedrich W. FUCHS, JÃ¶rg DANNEHL, Ralf LOHDE, Vincenz DINKHAUSER, Simon JENSEN, Andre KNOP, Kai ROTHENHAGEN, SÃ¶nke THOMSEN, Christian WESSELS [View]
[Download]

Abstract: Power generated from wind is actually a very great and a very fast growing renewable source of the world energy consumption. Optimizing performance and costs is an important issue for wind turbine generators. A laboratory for comprehensive research on the four types of power electronic generator systems for wind turbine generators and for their grid integration is presented. It consists of drives in a downscaled power range, special developed devices for generating test conditions and for measurement as well as of numerical simulations. The laboratory is presented and research including measurements are shown.

   Three-Level Three-Phase Neutral-Point-Clamped Back-to-Back Converter Applied to a Wind Emulator
By Alejandro CALLE PRADO, Joan ROCABERT, Sergio BUSQUETS-MONGE, Josep BORDONAU, Salvador ALEPUZ, Joan PERACAULA [View]
[Download]

Abstract: This paper presents a three-level three-phase neutral-point-clamped back-to-back converter applied to a wind emulator, where a wind power generator is connected to the grid through the back-to-back converter. The converter regulates the power extracted from the generator and controls how this power is injected to the grid with the desired power factor. Two phase locked loops are in charge of synchronizing the generator-side and the grid-side converters, regardless of the rotor speed of the generator. DC-link neutral point voltage balance is performed by the modulation strategy of the back-to-back converter. Simulation and experimental results are provided to verify the correct performance of the system.

EPE 2009 - Topic 14-10 - DS: 'Wind and Ocean Power Generator Systems'
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2009 - Conference > EPE 2009 - Topic 14: 'Electrical Energy Generating Systems, Renewable Energy Systems' > EPE 2009 - Topic 14-10 - DS: 'Wind and Ocean Power Generator Systems'
	[return to parent folder]

	A Micro Wind Power Generation System Using Permanent Magnet Reluctance Generator By Hiroki GOTO, Hai-Jiao GUO, Osamu ICHINOKURA	[View] [Download]
Abstract: Permanent magnet reluctance generator (PMRG) has robust construction similar to switched reluctance generator (SRG), but PMRG requires no excitation unlike SRG. So, PMRG is suitable for a micro wind generation system because of its low cost on manufacturing and its simple control circuit. In the paper, a 250-watt micro wind power generation system using PMRG is proposed. First, a new magnetic circuit model of the PMRG is proposed and simulated dynamically with the power converter by a general-purpose circuit simulator. It is confirmed that the proposed model is acceptable by comparing with calculation results of finite element analysis (FEM). Second, the proposed micro wind generation system is totally simulated using the magnetic circuit model of the PMRG with power converters, maximum power tracking control scheme, and power smoothing system using electric double layer capacitor(EDLC). Finally, experimental results by a simulated wind turbine are presented. The proposed wind generation system employed with PMRG contributes to expand into low cost wind generation.

	A Modified Vector Control Strategy for DFIG Based Wind Turbines to Ride-through Voltage Dips By Ling PENG, FrÃ©dÃ©ric COLAS, Bruno FRANCOIS, Yongdong LI	[View] [Download]
Abstract: Nowadays, the wind market is dominated by doubly fed induction generator (DFIG) based wind turbines. However, they are very sensitive to grid faults due to the small rated power converters and direct connection to the grid. In order to improve its Low Voltage Ride-Through (LVRT) capability, this paper proposes a modified vector control strategy of the DFIG by considering the dynamics of stator flux deduced by grid voltage dip. The limitation of the proposed scheme is also presented with a feasible region, which indicates the necessity of additional protection implementation such as crowbar. Then coordinated control strategies are proposed to enhance the LVRT performance with grid voltage support capability. Simulation results show the effectiveness of the proposed control schemes.

	Analysis of Three-phase Short Circuit Current of DFIG By Xueguang ZHANG, Rui LI, Dianguo XU	[View] [Download]
Abstract: The paper analyzes the theory of generating short circuit current during three-phase fault to research the low voltage ride through (LVRT) control of doubly fed induction generator (DFIG). The approximate analytical expressions of short circuit current are given in the condition of no load and synchronous speed to simplify the analysis. Based on this, the influences of different pre-fault conditions, such as reactive power, active power and speed, on short circuit current of DFIG are studied. At last, a 3MW DFIG model is built and the simulation is done to validate the theory analysis.

	Design of Power Converter driving a Linear Generator for Wave Energy Applications By Marcos BLANCO, gustavo NAVARRO, Marcos LAFOZ	[View] [Download]
Abstract: This paper describes aspects of the power electronics control of wave energy conversion. The objective of the power converter is to drive a switched reluctance linear machine which works as direct-drive power take off (DDPTO) system for a point absorber. FEM analysis and simulations of the electrical machine were taken into account in the design of the converter control strategy. Finally, laboratory testing will be described in the paper.

	DFIG based standalone power system operating at low load conditions. By Grzegorz IWANSKI	[View] [Download]
Abstract: The comparison of inductive and capacitive filter for standalone variable speed operated doubly fed induction generator DFIG is presented in the paper. Simulation and experimental results of both methods of filtration are shown. The model equations with stator connected filtering capacitors are analyzed. Sensorless control of the stator voltage vector in the polar frame is described. PLL based frequency control of generated stator voltage is presented. Modification of the control system allow for faster synchronization of the actual and reference voltage vector, what provide shorter start-up procedure of the system and better stabilization especially at low load conditions. Simulation and experimental results of improved frequency control of the standalone doubly fed induction generator are presented.

	High efficiency field oriented control of an induction generator for a tidal current turbine By Salvatore DE CARO, Antonio TESTA, Tommaso SCIMONE	[View] [Download]
Abstract: The paper discusses potential advantages in using an efficiency optimized field orientation strategy to control a variable speed induction generator exploiting the energy of tidal currents. The rotor flux of the induction generator is managed in order to minimize the total losses according to an off-line efficiency optimization strategy. The evaluation of potential advantages in using the efficiency optimized field orientation technique is carried out by experimental tests performed on a scale model and by simulations of a 18 kW induction generator prototype. Obtained results show that an encouraging 11\% increment of the produced energy can be obtained without additional costs.

	Investigations on Energy Yield and Power Fluctuation from Different Control Methods for Wind Energy Converters at Various Wind Conditions By Bingchang NI, Constantinos SOURKOUNIS	[View] [Download]
Abstract: The share of electricity generated by wind power converters is world wide steadily growing. With increasing shares of wind energy in the electrical power supply, their influence on the mains stability and their reliable energy contribution will become more relevant. Especially at points of common coupling of weak grid branches fluctuating power output of wind energy converters can be harmful for the grid stability. The system management of wind energy converters has great influence on the power yield and the damping/amplification of wind caused power fluctuations. This paper compares a new control approach, the Stochastic Dynamic Optimization, with common control methods, regarding their power yield and electrical power output fluctuation for different wind conditions. The results show that the Stochastic Dynamic Optimization control approach has superior performance regarding the power yield and low power output fluctuation.

	Management of Power Excess in Wind Turbine Systems By natalia angela ORLANDO, marco LISERRE, antonio DELL'AQUILA	[View] [Download]
Abstract: Variable speed wind turbine generators provide the opportunity to capture more power than fixed speed turbines. However also the limitation of the produced power is an important issue. The paper is focused on the management of the power in excess in a variable-speed wind turbine equipped with a PMSG (Permanent Magnet Synchronous Generator) connected to the grid through a back-to-back converter. It is investigated the role of the braking chopper to dissipate the power in excess that can not be injected in the grid and the blade pitch control to limit the aerodynamic power in above-rated wind speeds in order to keep the turbine within its design limits. The interaction between the blade pitch control and the braking chopper is discussed. Finally, some simulation results in the case of a ramping wind speed and under real wind conditions are reported.

	Maximum Power Tracking of Wind Power Generation System with Inverter Excited Induction Machine By Noriyuki KIMURA, Tomoyuki HAMADA, Makoto SONODA, Kenichi NAKATANI, toshimitsu MORIZANE, Katsunori TANIGUCHI, Yasuyuki NISHIDA	[View] [Download]
Abstract: This paper shows a new induction generation system for wind power generation. This system has the voltage source converter exciting induction generator and the PFC converter to transfer the real power. This configuration enables asynchronous link and maximum power tracking for the cage rotor induction generator. Usually two full rating inverter sets are necessary to construct the asynchronous link. Proposed system uses an inverter of small rating, 10\% of full rating, and a PFC converter can replace the roll of the real power transfer at the generator side. This configuration can reduce the total system costs. This paper has investigated the maximum power point tracking control of the proposed system by simulation. The simulation results show the good tracking ability and certify the reduction of the inverter rating at the generator side.

	Modelling and Control in Wind Energy Conversion Systems (WECS) By Luis GONZALEZ	[View] [Download]
Abstract: This paper encompasses the study of modelling and design of WECS, using a wind turbine with known dynamic characteristics and a permanent magnet synchronous generator driven by a back to back power converter topology. The dynamic modeling allows to know the response of the turbine generator system in the whole range of operation. In this study, it is proposed a variable structure control scheme with two different kind of operation, namely Maximum Power Point Tracking (MPPT) and Constant Power (CP). In the CP region, it is demonstrated that the system is controllable with the speed control loop while that using torque control an unstable control loop results.

	New Design Control Dedicated To Low Voltage Ride Through of Hybrid Wind Plant By Alexandre TENINGE	[View] [Download]
Abstract: In this paper, the low voltage ride-through (LVRT) capabilities of an hybrid wind plant is studied. The hybrid wind plant considered combines fixed speed wind turbines (FSWTs) based on classical induction generator and full power converter variable speed wind turbines (VSWTs) with permanent magnet generator. However, it must be able to respect grid code requirements. A specific control of the variable speed wind turbine power converters is proposed and described in this paper to support FSWTs during voltage dips: the gride side converter is used as a STATCOM during voltage drop to provide the maximum of reactive power. Simulation results show the ability of the wind plant to ride-through a voltage dip with this control.

	Peak Current Mode Control of a Boost Rectifier with Low Distortion of the Input Current for Wind Power Systems based on Permanent Magnet Synchronous Generators By OSCAR CARRANZA, EMILIO FIGUERES, GABRIEL GARCERA, LUIS GERARDO GONZALEZ, FRAN GONZALEZ-ESPIN	[View] [Download]
Abstract: This paper presents a Peak Current Mode Control of a Boost Rectifier with Low Distortion of the Input Current for Wind Power Systems based on Permanent Magnet Synchronous Generators with variable speed operation. The Three-Phase Boost Rectifier is operated in Discontinuous Conduction Mode (DCM). It is shown that the DCM operation significantly reduces the Total Harmonics Distortion of the currents in the Permanent Magnet Synchronous Generator, increasing the Power Factor of the system, so that the vibrations and mechanical stress of the generator is minimized. The characteristics of the DCM Boost rectifier are studied considering: 1) The series resistance of the inductors; 2) The modeling and adjustment of peak current mode control yielding a stable loop; 3) The design of an input filter that reduces the switching noise in the currents of the generator.

	Reactive Power Analysis and Control of Doubly Fed Induction Generator Wind Farm By Dianguo XU, Rui LI, Yicheng LIU, Yongqiang LANG	[View] [Download]
Abstract: Power relations of doubly fed induction generator (DFIG) wind power generation system are analyzed. Based on this, a method is proposed to calculate the reactive power limit. Furthermore, the reactive power control of DFIG wind farm is studied and the control scheme is provided to exert the reactive power dealing capability of wind power system. A reactive power compensation strategy for the local user using DFIG wind farm and the distribution algorithms of reactive power demand are given. Simulation results are provided to verify the proposed theory.

	Research Laboratory for Power Electronic Generator Systems in Wind Turbines Comprising Converters, Generators, Interaction and Grid Interaction By Friedrich W. FUCHS, JÃ¶rg DANNEHL, Ralf LOHDE, Vincenz DINKHAUSER, Simon JENSEN, Andre KNOP, Kai ROTHENHAGEN, SÃ¶nke THOMSEN, Christian WESSELS	[View] [Download]
Abstract: Power generated from wind is actually a very great and a very fast growing renewable source of the world energy consumption. Optimizing performance and costs is an important issue for wind turbine generators. A laboratory for comprehensive research on the four types of power electronic generator systems for wind turbine generators and for their grid integration is presented. It consists of drives in a downscaled power range, special developed devices for generating test conditions and for measurement as well as of numerical simulations. The laboratory is presented and research including measurements are shown.

	Three-Level Three-Phase Neutral-Point-Clamped Back-to-Back Converter Applied to a Wind Emulator By Alejandro CALLE PRADO, Joan ROCABERT, Sergio BUSQUETS-MONGE, Josep BORDONAU, Salvador ALEPUZ, Joan PERACAULA	[View] [Download]
Abstract: This paper presents a three-level three-phase neutral-point-clamped back-to-back converter applied to a wind emulator, where a wind power generator is connected to the grid through the back-to-back converter. The converter regulates the power extracted from the generator and controls how this power is injected to the grid with the desired power factor. Two phase locked loops are in charge of synchronizing the generator-side and the grid-side converters, regardless of the rotor speed of the generator. DC-link neutral point voltage balance is performed by the modulation strategy of the back-to-back converter. Simulation and experimental results are provided to verify the correct performance of the system.