EPE Association: EPE 1985 - 08 - Lecture Session 2.01: CONTROL SYSTEMS FOR LOCAL POWER PLANTS

EPE 1985 - 08 - Lecture Session 2.01: CONTROL SYSTEMS FOR LOCAL POWER PLANTS
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   WIND ENERGY FARM WITH SYNCHRONOUS GENERATORS OPERATING ON A COMMON DC LINK
By J. Ernst [View]
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Abstract: The paper deals with the characteristics and the control of a wind energy farm with synchronous generators and a d.c.-link converter. The main topic of the paper is the analysis of the electrical behaviour of a synchronous machine with a diode-bridge rectifier. The reasons for possible instability are discussed as well as solutions for stabilizing the system. The machines are equipped with a torque and speed controller adjusting the generator field voltage and the rotor blade angle respectively. An extinction-angle controller reduces the reactive power drawn by the inverter while a constant capacitor compensation combined with a reactive power controller leads to a unity power factor over the whole operating power range of the wind energy farm.

   MICROPROCESSOR CONTROL OF WIND DRIVEN SQUIRREL CAGE INDUCTION GENERATOR
By S. Naganathan; A. M. Sharaf [View]
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Abstract: The variable speed, variable frequency wind energy conversion schemes are becoming popular in the recent years. This type of scheme uses a squirrel cage Induction Generator driven by a vertical axis wind turbine. The Induction Generator is self excited by fixed shunt capacitors. The inherent poor voltage and frequency regulation of the Induction Generator are overcome by the AC/DC/AC asychronous link where the a.c. power delivered by the generator is converted to d.c. and fed to the a.c. utility system through an inverter. It is possible to maintain a constant voltage at the load and by controlling the firing angle of the rectifier bridge. The complete system consists of an Induction Motor with suitable fixed shunt capacitors, driven by a d.c. motor, and the controlled three phase rectifier with a load. A control strategy is developed to maintain the voltage at the load and constant, by controlling the firing angle of the rectifier bridge for a wide range of speed and load conditions. The proposed controller has been designed, implemented and successfully tested using an Intel 8085 microcomputer system.

   POWER OPTIMIZATION FOR AN AEROGENERATOR CONTROLLED BY MEANS OF A MICROCOMPUTER
By C. Kraif; C. Masselot [View]
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Abstract: Because the high cost of a windmill it is important to transfer all the available electric power to the load regardless the wind conditions. Such operation is obtained by means of an electric chopper controlled by a micro-computer. After many tests of maximum power tracking using wind velocity or aerogenerator rotation speed and generated electric power controlled parameters, we propose an appropriate algorithm which control the chopper duty cycles from electric power variations taking into account the high aerogenerator inertia. Moreover, the windmill command is fully automatic and it meets the three criteria economy, independance and reliability - necessary for use on suitable site in the Sahel.

   A TWELVE PULSE CURRENT SOURCE INVERTER AS A STATIC VAR COMPENSATOR IN THE LINK BETWEEN A LOCAL POWER PLANT AND A WEAK POWER GRID
By L. J. J. Offringa; W. J. De Zeeuw [View]
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Abstract: The application of a twelve pulse current source inverter in the link between a local power plant and a weak power grid is described. The design of a conversion system which is specially intended for wind energy applications will be discussed. The system may also be used for a total energy plant or a water turbine. The possibility of power factor control by means of the inverter firing angle control is explained. In particular the use of the inverter as a static VAR regulator is described. Some measurements on a 60 kW realised laboratory prototype are given.

EPE 1985 - 08 - Lecture Session 2.01: CONTROL SYSTEMS FOR LOCAL POWER PLANTS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1985 - Conference > EPE 1985 - 08 - Lecture Session 2.01: CONTROL SYSTEMS FOR LOCAL POWER PLANTS
	[return to parent folder]

	WIND ENERGY FARM WITH SYNCHRONOUS GENERATORS OPERATING ON A COMMON DC LINK By J. Ernst	[View] [Download]
Abstract: The paper deals with the characteristics and the control of a wind energy farm with synchronous generators and a d.c.-link converter. The main topic of the paper is the analysis of the electrical behaviour of a synchronous machine with a diode-bridge rectifier. The reasons for possible instability are discussed as well as solutions for stabilizing the system. The machines are equipped with a torque and speed controller adjusting the generator field voltage and the rotor blade angle respectively. An extinction-angle controller reduces the reactive power drawn by the inverter while a constant capacitor compensation combined with a reactive power controller leads to a unity power factor over the whole operating power range of the wind energy farm.

	MICROPROCESSOR CONTROL OF WIND DRIVEN SQUIRREL CAGE INDUCTION GENERATOR By S. Naganathan; A. M. Sharaf	[View] [Download]
Abstract: The variable speed, variable frequency wind energy conversion schemes are becoming popular in the recent years. This type of scheme uses a squirrel cage Induction Generator driven by a vertical axis wind turbine. The Induction Generator is self excited by fixed shunt capacitors. The inherent poor voltage and frequency regulation of the Induction Generator are overcome by the AC/DC/AC asychronous link where the a.c. power delivered by the generator is converted to d.c. and fed to the a.c. utility system through an inverter. It is possible to maintain a constant voltage at the load and by controlling the firing angle of the rectifier bridge. The complete system consists of an Induction Motor with suitable fixed shunt capacitors, driven by a d.c. motor, and the controlled three phase rectifier with a load. A control strategy is developed to maintain the voltage at the load and constant, by controlling the firing angle of the rectifier bridge for a wide range of speed and load conditions. The proposed controller has been designed, implemented and successfully tested using an Intel 8085 microcomputer system.

	POWER OPTIMIZATION FOR AN AEROGENERATOR CONTROLLED BY MEANS OF A MICROCOMPUTER By C. Kraif; C. Masselot	[View] [Download]
Abstract: Because the high cost of a windmill it is important to transfer all the available electric power to the load regardless the wind conditions. Such operation is obtained by means of an electric chopper controlled by a micro-computer. After many tests of maximum power tracking using wind velocity or aerogenerator rotation speed and generated electric power controlled parameters, we propose an appropriate algorithm which control the chopper duty cycles from electric power variations taking into account the high aerogenerator inertia. Moreover, the windmill command is fully automatic and it meets the three criteria economy, independance and reliability - necessary for use on suitable site in the Sahel.

	A TWELVE PULSE CURRENT SOURCE INVERTER AS A STATIC VAR COMPENSATOR IN THE LINK BETWEEN A LOCAL POWER PLANT AND A WEAK POWER GRID By L. J. J. Offringa; W. J. De Zeeuw	[View] [Download]
Abstract: The application of a twelve pulse current source inverter in the link between a local power plant and a weak power grid is described. The design of a conversion system which is specially intended for wind energy applications will be discussed. The system may also be used for a total energy plant or a water turbine. The possibility of power factor control by means of the inverter firing angle control is explained. In particular the use of the inverter as a static VAR regulator is described. Some measurements on a 60 kW realised laboratory prototype are given.