EPE Association: EPE 1997 – 42: Dialogue Session DS8h: ADJUSTABLE SPEED GENERATORS

EPE 1997 – 42: Dialogue Session DS8h: ADJUSTABLE SPEED GENERATORS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 42: Dialogue Session DS8h: ADJUSTABLE SPEED GENERATORS

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   STEADY-STATE POWER FLOW AND EFFICIENCY OPTIMIZING ANALYSIS OF A VARIABLE SPEED CONSTANT FREQUENCY GENERATING SYSTEM
By P. A. Edvardsen; T. F. Nestli; R. Nilsen; H. Kolstad [View]
[Download]

Abstract: This paper presents the steady-state power flow in a variable speed constant frequency generating system. The power flow in the system is analyzed when over all network power reference is specified. Optimal operation with respect to system losses is calculated for different combinations of generated active and reactive power.·

   CONTROL CHARACTERISTICS OF AN ADJUSTABLE SPEED GENERATION SYSTEM WITH A FLYWHEEL EXCITED BY A DC LINK CONVERTER
By T. Nishio; K. Minoguti; S. Uno; M. Hombu; M. Futami; M. Higuchi [View]
[Download]

Abstract: Excellent control performance is obtained in a 30-kV A test model of an adjustable speed generation system with a flywheel excited by a de link IGBT converter. Performance values include quick active/reactive currents response in an induction machine of 175 rad/s, active power response of 40 rad/s and voltage response of 20 rad/s. Moreover, continuous operation can be realized even during such electric power network faults as 1-line, 2-line and 3- line ground faults.

   APPLICATION OF VECTOR CONTROL TO THE CASCADED INDUCTION MACHINE FOR WIND POWER GENERATION SCHEMES
By B. Hopfensperger; D. J. Atkinson; R. A. Lakin [View]
[Download]

Abstract: Cascaded doubly-fed induction machines (CDFM) have recently been receivlng renewed interest for use as bmshless variable speed wind power generators with reduced converter rating requirements. Vector control can be applied for independent control of generated active and reactive power. This paper examines the dynamic performance of the machine. Control of the active and reactive power by field orientation techniques is illustrated. The laboratory test rig of two 2.25kW vector controlled cascaded machines is described.

   STABILITY ANALYSIS OF DOUBLY-FED INDUCTION MACHINES IN STATOR FLUX REFERENCE FRAME
By M. Heller; W. Schumacher [View]
[Download]

Abstract: Recent progress in power electronics made it possible to combine high power converters with motor/generators of power plants. Especially pumped storage power plants combined with doubly-fed motor/generators benefit from an improved efficiency in turbine mode. This article presents mathematical analysis concerning transient performance of a doubly-fed induction machine; simulation plots and measured data obtained with a 33kW test rig are included.

   VECTOR CONTROL OF AN AUTONOMOUS INDUCTION GENERATOR CONNECTED TO A PWM RECTIFIER
By C. Colliez; A. Tounzia; F. Piriou [View]
[Download]

Abstract: This communication deals with the study and the control of an induction generator intended to produce electrical energy in an autonomous wind station. To provide it the necessary reactive power, the machine is connected to a PWM rectifier. Furthermore, as the whole system is not linked to the network, for an autonomous running, the voltage at the terminals of the rectifier must be kept constant whatever the speed of the rotor and the load. To reach this purpose, we propose an electrical control of the whole system In a first part, we achieve a modeling of the machine in a d-q frame taking into account the saturation and the cross magnetizing effects. The second part deals with the vector control of the whole system. This is achieved in a same manner as a motor operating by keeping a constant flux in the machine and controlling the DC voltage at the terminals of the rectifier. A numerical program has been developed to analyze the behavior of the whole system controlled thanks to the proposed scheme. Results for a voltage built up, as well as the responses of the system to different disturbances of load and rotor speed are given and discussed.

   ROTOR CIRCUIT GTO CONVERTER FOR SLIP RING INDUCTION MACHINE
By H. Weiss [View]
[Download]

Abstract: A rotating system tie frequency converter for supplying 16 2/3 Hz power to the variable frequency railway network comprises a double-fed slip ring induction machine at the 3- phase 50 Hz side. As the operating speed will not differ from the synchronous spe.ed by more than a few percent, only the same small part of transferred power - the slip power - appears at the rotor side. The appropriate rotor voltage for the setpoint value of shaft torque is generated by a PWM inverter with a DC link; usually low voltage and high current will be found in power transfer operation at the rotor side. In the state of the art solution, a line commutated thyristor rectifier I inverter, connected to a line transformer, accomplishes the further transfer of active power to the line. This proposed circuit consists of a second PWM inverter instead of the thyristor unit. The novel circuitry is compared to the standard. By proper line PWM inverter control, induction machine losses can be reduced and the transient behavior at line faults can be improved essentially (reduced peak currents and reduced time for regaining undisturbed operation). Additionally, it is possible to reduce the rated power of the converter transformer.

   DESIGN AND CONTROL OF A WIND POWER STATION WITH DOUBLE FED INDUCTION GENERATOR
By A. Dittrich; W. Hofmann; A. Stoev; A. Thieme [View]
[Download]

Abstract: The paper refers to a realized power generation system with a double-fed induction machine for using in wind power stations. For modelling the controlled induction generator system the field orientation and line-voltage orientation methods are compared. The final design of the control-unit was based on the line-voltage orientation and the controllers are supplied with torque and sin

   EXPERIMENTAL COMPARlSON OF pq AND EXTENSION pq METHOD FOR ACTIVE POWER FILTER
By Y. Komatsu; T. Kawabata [View]
[Download]

Abstract: In this paper, the authors propose a calculation method for the compensating current reference of the active power filter, where a nonlinear load exists in the three-phase three-wire unsymmetrical voltage system. This new method has been named extension pq method. The authors have experimented with the extension pq method and the pq method, using the same current controlled IPM inverter for both methods. The results of the experiments proved that in the unsymmetrical voltage system, the source current was distorted in case of the pq method, but undistorted in case of the extension pq method.

   Network Feeder with Synchronous Generator for Variable Speed Wind Turbines as a Laboratory Model
By U. Raedel; G. Berger; J. Petzoldt [View]
[Download]

Abstract: To feed energy into the line with variable speed wind turbines, various control problems are treated. This contribution considers the whole system behavior by means of a laboratory model. The main emphasis does the fieldoriented sensorless control of the synchronous generator. Further components are an imitation of the wind rotor by a direct-current drive and the control of the main current.

   1.5 MW WIND POWER STATION WITH LOW AC-LINE DISTORTION USING A STANDARD DOUBLY-FED GENERATOR SYSTEM WITH FIELD ORIENTATION CONTROL
By B. Eggert [View]
[Download]

Abstract: Wind power stations increased up to 1.5 MW to become more profitable. For high efficiency the generator has to be controlled at variable speed. A very useful solution is the doubly-fed generator combined with lower rating standard PWM-inverters at the rotor side to get also a good power quality with low ac-line voltage distortions.

EPE 1997 – 42: Dialogue Session DS8h: ADJUSTABLE SPEED GENERATORS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 42: Dialogue Session DS8h: ADJUSTABLE SPEED GENERATORS
	[return to parent folder]

	STEADY-STATE POWER FLOW AND EFFICIENCY OPTIMIZING ANALYSIS OF A VARIABLE SPEED CONSTANT FREQUENCY GENERATING SYSTEM By P. A. Edvardsen; T. F. Nestli; R. Nilsen; H. Kolstad	[View] [Download]
Abstract: This paper presents the steady-state power flow in a variable speed constant frequency generating system. The power flow in the system is analyzed when over all network power reference is specified. Optimal operation with respect to system losses is calculated for different combinations of generated active and reactive power.·

	CONTROL CHARACTERISTICS OF AN ADJUSTABLE SPEED GENERATION SYSTEM WITH A FLYWHEEL EXCITED BY A DC LINK CONVERTER By T. Nishio; K. Minoguti; S. Uno; M. Hombu; M. Futami; M. Higuchi	[View] [Download]
Abstract: Excellent control performance is obtained in a 30-kV A test model of an adjustable speed generation system with a flywheel excited by a de link IGBT converter. Performance values include quick active/reactive currents response in an induction machine of 175 rad/s, active power response of 40 rad/s and voltage response of 20 rad/s. Moreover, continuous operation can be realized even during such electric power network faults as 1-line, 2-line and 3- line ground faults.

	APPLICATION OF VECTOR CONTROL TO THE CASCADED INDUCTION MACHINE FOR WIND POWER GENERATION SCHEMES By B. Hopfensperger; D. J. Atkinson; R. A. Lakin	[View] [Download]
Abstract: Cascaded doubly-fed induction machines (CDFM) have recently been receivlng renewed interest for use as bmshless variable speed wind power generators with reduced converter rating requirements. Vector control can be applied for independent control of generated active and reactive power. This paper examines the dynamic performance of the machine. Control of the active and reactive power by field orientation techniques is illustrated. The laboratory test rig of two 2.25kW vector controlled cascaded machines is described.

	STABILITY ANALYSIS OF DOUBLY-FED INDUCTION MACHINES IN STATOR FLUX REFERENCE FRAME By M. Heller; W. Schumacher	[View] [Download]
Abstract: Recent progress in power electronics made it possible to combine high power converters with motor/generators of power plants. Especially pumped storage power plants combined with doubly-fed motor/generators benefit from an improved efficiency in turbine mode. This article presents mathematical analysis concerning transient performance of a doubly-fed induction machine; simulation plots and measured data obtained with a 33kW test rig are included.

	VECTOR CONTROL OF AN AUTONOMOUS INDUCTION GENERATOR CONNECTED TO A PWM RECTIFIER By C. Colliez; A. Tounzia; F. Piriou	[View] [Download]
Abstract: This communication deals with the study and the control of an induction generator intended to produce electrical energy in an autonomous wind station. To provide it the necessary reactive power, the machine is connected to a PWM rectifier. Furthermore, as the whole system is not linked to the network, for an autonomous running, the voltage at the terminals of the rectifier must be kept constant whatever the speed of the rotor and the load. To reach this purpose, we propose an electrical control of the whole system In a first part, we achieve a modeling of the machine in a d-q frame taking into account the saturation and the cross magnetizing effects. The second part deals with the vector control of the whole system. This is achieved in a same manner as a motor operating by keeping a constant flux in the machine and controlling the DC voltage at the terminals of the rectifier. A numerical program has been developed to analyze the behavior of the whole system controlled thanks to the proposed scheme. Results for a voltage built up, as well as the responses of the system to different disturbances of load and rotor speed are given and discussed.

	ROTOR CIRCUIT GTO CONVERTER FOR SLIP RING INDUCTION MACHINE By H. Weiss	[View] [Download]
Abstract: A rotating system tie frequency converter for supplying 16 2/3 Hz power to the variable frequency railway network comprises a double-fed slip ring induction machine at the 3- phase 50 Hz side. As the operating speed will not differ from the synchronous spe.ed by more than a few percent, only the same small part of transferred power - the slip power - appears at the rotor side. The appropriate rotor voltage for the setpoint value of shaft torque is generated by a PWM inverter with a DC link; usually low voltage and high current will be found in power transfer operation at the rotor side. In the state of the art solution, a line commutated thyristor rectifier I inverter, connected to a line transformer, accomplishes the further transfer of active power to the line. This proposed circuit consists of a second PWM inverter instead of the thyristor unit. The novel circuitry is compared to the standard. By proper line PWM inverter control, induction machine losses can be reduced and the transient behavior at line faults can be improved essentially (reduced peak currents and reduced time for regaining undisturbed operation). Additionally, it is possible to reduce the rated power of the converter transformer.

	DESIGN AND CONTROL OF A WIND POWER STATION WITH DOUBLE FED INDUCTION GENERATOR By A. Dittrich; W. Hofmann; A. Stoev; A. Thieme	[View] [Download]
Abstract: The paper refers to a realized power generation system with a double-fed induction machine for using in wind power stations. For modelling the controlled induction generator system the field orientation and line-voltage orientation methods are compared. The final design of the control-unit was based on the line-voltage orientation and the controllers are supplied with torque and sin

	EXPERIMENTAL COMPARlSON OF pq AND EXTENSION pq METHOD FOR ACTIVE POWER FILTER By Y. Komatsu; T. Kawabata	[View] [Download]
Abstract: In this paper, the authors propose a calculation method for the compensating current reference of the active power filter, where a nonlinear load exists in the three-phase three-wire unsymmetrical voltage system. This new method has been named extension pq method. The authors have experimented with the extension pq method and the pq method, using the same current controlled IPM inverter for both methods. The results of the experiments proved that in the unsymmetrical voltage system, the source current was distorted in case of the pq method, but undistorted in case of the extension pq method.

	Network Feeder with Synchronous Generator for Variable Speed Wind Turbines as a Laboratory Model By U. Raedel; G. Berger; J. Petzoldt	[View] [Download]
Abstract: To feed energy into the line with variable speed wind turbines, various control problems are treated. This contribution considers the whole system behavior by means of a laboratory model. The main emphasis does the fieldoriented sensorless control of the synchronous generator. Further components are an imitation of the wind rotor by a direct-current drive and the control of the main current.

	1.5 MW WIND POWER STATION WITH LOW AC-LINE DISTORTION USING A STANDARD DOUBLY-FED GENERATOR SYSTEM WITH FIELD ORIENTATION CONTROL By B. Eggert	[View] [Download]
Abstract: Wind power stations increased up to 1.5 MW to become more profitable. For high efficiency the generator has to be controlled at variable speed. A very useful solution is the doubly-fed generator combined with lower rating standard PWM-inverters at the rotor side to get also a good power quality with low ac-line voltage distortions.