EPE Association: Pelincec 2005 - 11: Dialog I

Pelincec 2005 - 11: Dialog I - Renewable Energy
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   ACTIVE COMPENSATOR OF DC LOAD POWER VARIABILITY
By Grzegorz Wodecki, Wlodzimierz Koczara [View]
[Download]

Abstract: Paper present theory and application of new type of compensator of active power variability. The compensator bases on supercapaictor energy storage and power electronic converter. To control the source current the load current is sensed and then the running average current is calculated. A difference of the load current and running average is used to produce reference compensator current. Results of simulations and laboratory tests of DC power system confirms quality of the compensator operation.

   Paralleling Synchronous Generator and Induction Generator in Island Grids
By I. Serban, C. Ion, C. Marinescu, L. Clotea, M. Cirstea [View]
[Download]

Abstract: The paper presents the interconnection between an induction and a synchronous generator on an autonomous microgrid that is part of a hybrid power system with renewable energies. The research work investigates a control solution for the power circulation (real and reactive power) in the system, under variable load, in order to keep the parameters of the produced energy within the standard variation limits. A common regulation circuit is being developed, to ensure the stable operation of the entire system. The power control circuit consists of a frequency controller based on a dump load and a common voltage regulator for the two generators. For the chosen system configuration a series of simulations were accomplished for variable loads and mechanical power.

   Modelling and Simulation of Fuel Cell Powered Electrical Car Drive System
By Przemyslaw Majewski, Wlodzimierz Koczara [View]
[Download]

Abstract: The paper presents modelling and simulation of the electrical car powered from fuel cell. The performance of the fuel cell do not assure demanded dynamic of the car motion. Therefore an additional energy storages as supercapacitors and batteries equipped in power electronic converters are used. Proposed power system topology and control system of power and energy flow is designed to safe long life of the fuel cell and high dynamic performance of the car motion.

   Modeling of Adjustable Speed Generation System with Liquid Fuel and Gas Powered Engine
By Zdzislaw Chlodnicki, Wlodzimierz Koczara, Nazar Al-Khayat [View]
[Download]

Abstract: Hydrogen is a future fuel which will be used in electrical power generation systems. There are two main streams of works on the hydrogen application. In the first there is direct conversion of hydrogen to electricity by fuel cells. The fuel cells are recently very intensively developed but the progress is still to slow. In the second stream the hydrogen is used as fuel in internal combustion engines. The efficiency of internal combustion engine is lower than in fuel cell but the technology of the internal combustion engine is simpler. Main works are carried to use the hydrogen in automotive engines. In this paper is considered application of the hydrogen power engine in adjustable speed generation systems. The paper presents modeling and simulation of the adjustable speed generation system with internal combustion engine, permanent magnet generator and power electronic converter. The engine speed is adjusted to meet load power demand. The power electronic converter is producing three phase AC fixed frequency voltage.

   Modelling and Simulation of a Synchronous Machine with Power Electronic Systems
By Z. Chen, F. Blaabjerg [View]
[Download]

Abstract: This paper reports the modeling and simulation of a synchronous machine with a power electronic interface in direct phase model. The implementation of a direct phase model of synchronous machines in MATLAB/SIMULINK is presented .The power electronic system associated with the synchronous machine is modelled in SIMULINK as well. The resulting model can more accurately represent non-idea situations such as non-symmetrical parameters of the electrical machines and unbalance conditions. The model may be used for both steady state and large-signal dynamic analysis. This is particularly useful in the systems where a detailed study is needed in order to assess the overall system stability. Simulation studies are performed under various operation conditions. It is shown that the developed model could be used for studies of various applications of synchronous machines such as in renewable and DG generation systems

   Unified Power Quality Conditioner in a Grid Connected Photovoltaic System
By Marcelo Cabral Cavalcanti, Gustavo Medeiros de Souza Azevedo, Bruno de Aguiar Amaral, Francisco de Assis dos Santos Neves [View]
[Download]

Abstract: This paper presents a system that provides photovoltaic generation as well as the functions of a unified power quality conditioner. The system can be controlled for current harmonics and reactive power compensation simultaneously by using a converter operating as active shunt filter. The other converter is used as active series filter and it compensates voltage harmonics or voltage sags and swells. Using only an inverter in photovoltaic energy conversion process, the system presents increased efficiency when compared to the conventional systems. The synchronous reference frame method is used to control the three-phase converters. Simulation results demonstrate the good performance of the proposed configuration. Experimental results corresponding to the operation of the series filter as voltage sag compensator are presented.

   Maximum Power Point Tracking Techniques for Photovoltaic Systems
By Marcelo Cabral Cavalcanti, Kleber Carneiro de Oliveira, Gustavo Medeiros de Souza Azevedo, Davi Carvalho Moreira, Francisco de Assis dos Santos Neves [View]
[Download]

Abstract: This paper presents a comparative study among maximum power point tracking methods for photovoltaic systems. The comparison takes into account steady state error, dynamic response and efficiency in a large power range. In special, an extensive bibliography and a classification of many maximum power point tracking methods is presented. Computational simulations with fast changes in the solar radiance have been done and the best maximum power point tracking technique is chosen.

   Contactless multipolar doubly-fed asynchronous generator for windmills
By N. Levin, V. Pugachov, L. Ribickis, A. Zhiravetska [View]
[Download]

Abstract: A multipolar contactless doubly-fed asynchronous generator is considered where the primary and secondary generation windings are arranged on the teeth of the stator, while the rotor is tooth-like and without windings. Analytical treatment of such a generator has been performed and the basic equations that allow the parameters and performance of the machine to be calculated in generation mode of operation have been obtained. The results of experimental investigations are presented for the physical model of the generator and comparison with the calculation data is given.

   Application of Z-Source Converter in Photovoltaic Grid-Connected Transformer-Less Inverter
By Babak Farhangi, Shahrokh Farhangi [View]
[Download]

Abstract: In PV grid connected power conditioners, usually both boosting the PV array voltage, and bucking the dc bus voltage for injection of a sinusoidal current to the grid is required. In this paper the design procedure of Z-source converter as a single phase PV grid connected transformer-less inverter is presented. The converter has one switch less than the conventional two stage power conditioner, which leads to reduction of cost. An optimum modulation pattern for the switches is proposed. The design of the converter is verified by simulation.

   ROBUST FAULT DIAGNOSIS OF A WIND POWER STATION
By Wojciech Jarzyna [View]
[Download]

Abstract: The paper presents fault isolation approach of a wind power station based on model-based diagnosis. The main attention is focused on a wind turbine for which the state equation is formulated. Certain faults occurring in described turbine blades are represented by change of equation parameters. The knowledge about the disturbances are obtained from measured and estimated instantaneous angular velocity of the shaft. The desired sensitivity assures applied robust observers, which decouple changes of selected wind engine parameters from computed outputs. Generated residuals allow to isolate a blade elasticity and its oscillation damping and damping of the rotation a drive train.

   Development of Wind Turbine Simulators Using PSCAD
By Ahmed Abo-Khalil, Dong-Choon Lee [View]
[Download]

Abstract: In this paper, a wind turbine simulator is developed using PSCAD. The wind turbine static characteristics are modeled using the relation among the turbine power, the wind speed, and the blade pitch angle. Also, the dynamic characteristics of the wind turbine are modeled through a two-mass oscillating system, representing the turbine and the generator connected by elastic shaft. The system considered is designed to show the effects of the tower shadow effect and blades asymmetry. Torsional oscillation effect on the drive train is also considered. A pitch angle controller is used to limit the turbine output power to the rated value to protect the coupled generator. Simulation results are presented to verify the wind turbine simulator performance.

   Transient Current Limitation of the Cage Induction Generator Connected to the Grid
By Marcin Grzeczkowicz, Wlodzimierz Koczara, Zbigniew Szulc [View]
[Download]

Abstract: The paper presents a control method of start of a large cage induction motor. The starting process consists of two main states. In the first state a power electronic inverter is used to control the speed and current of accelerating motor. Therefore the grid current is fully controlled and adjusted to references. In the second state the power electronic inverter is off and the motor is connected directly to grid. A method of synchronization of the induced emf. of the motor to the grid voltage reduces transient current and torque jerk. However, relatively long time of the electromechanical transfer switch operation results in displacement of the emf. and increase of the stator current.

Pelincec 2005 - 11: Dialog I - Renewable Energy
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > Pelincec 2005 > Pelincec 2005 - 11: Dialog I - Renewable Energy
	[return to parent folder]

	ACTIVE COMPENSATOR OF DC LOAD POWER VARIABILITY By Grzegorz Wodecki, Wlodzimierz Koczara	[View] [Download]
Abstract: Paper present theory and application of new type of compensator of active power variability. The compensator bases on supercapaictor energy storage and power electronic converter. To control the source current the load current is sensed and then the running average current is calculated. A difference of the load current and running average is used to produce reference compensator current. Results of simulations and laboratory tests of DC power system confirms quality of the compensator operation.

	Paralleling Synchronous Generator and Induction Generator in Island Grids By I. Serban, C. Ion, C. Marinescu, L. Clotea, M. Cirstea	[View] [Download]
Abstract: The paper presents the interconnection between an induction and a synchronous generator on an autonomous microgrid that is part of a hybrid power system with renewable energies. The research work investigates a control solution for the power circulation (real and reactive power) in the system, under variable load, in order to keep the parameters of the produced energy within the standard variation limits. A common regulation circuit is being developed, to ensure the stable operation of the entire system. The power control circuit consists of a frequency controller based on a dump load and a common voltage regulator for the two generators. For the chosen system configuration a series of simulations were accomplished for variable loads and mechanical power.

	Modelling and Simulation of Fuel Cell Powered Electrical Car Drive System By Przemyslaw Majewski, Wlodzimierz Koczara	[View] [Download]
Abstract: The paper presents modelling and simulation of the electrical car powered from fuel cell. The performance of the fuel cell do not assure demanded dynamic of the car motion. Therefore an additional energy storages as supercapacitors and batteries equipped in power electronic converters are used. Proposed power system topology and control system of power and energy flow is designed to safe long life of the fuel cell and high dynamic performance of the car motion.

	Modeling of Adjustable Speed Generation System with Liquid Fuel and Gas Powered Engine By Zdzislaw Chlodnicki, Wlodzimierz Koczara, Nazar Al-Khayat	[View] [Download]
Abstract: Hydrogen is a future fuel which will be used in electrical power generation systems. There are two main streams of works on the hydrogen application. In the first there is direct conversion of hydrogen to electricity by fuel cells. The fuel cells are recently very intensively developed but the progress is still to slow. In the second stream the hydrogen is used as fuel in internal combustion engines. The efficiency of internal combustion engine is lower than in fuel cell but the technology of the internal combustion engine is simpler. Main works are carried to use the hydrogen in automotive engines. In this paper is considered application of the hydrogen power engine in adjustable speed generation systems. The paper presents modeling and simulation of the adjustable speed generation system with internal combustion engine, permanent magnet generator and power electronic converter. The engine speed is adjusted to meet load power demand. The power electronic converter is producing three phase AC fixed frequency voltage.

	Modelling and Simulation of a Synchronous Machine with Power Electronic Systems By Z. Chen, F. Blaabjerg	[View] [Download]
Abstract: This paper reports the modeling and simulation of a synchronous machine with a power electronic interface in direct phase model. The implementation of a direct phase model of synchronous machines in MATLAB/SIMULINK is presented .The power electronic system associated with the synchronous machine is modelled in SIMULINK as well. The resulting model can more accurately represent non-idea situations such as non-symmetrical parameters of the electrical machines and unbalance conditions. The model may be used for both steady state and large-signal dynamic analysis. This is particularly useful in the systems where a detailed study is needed in order to assess the overall system stability. Simulation studies are performed under various operation conditions. It is shown that the developed model could be used for studies of various applications of synchronous machines such as in renewable and DG generation systems

	Unified Power Quality Conditioner in a Grid Connected Photovoltaic System By Marcelo Cabral Cavalcanti, Gustavo Medeiros de Souza Azevedo, Bruno de Aguiar Amaral, Francisco de Assis dos Santos Neves	[View] [Download]
Abstract: This paper presents a system that provides photovoltaic generation as well as the functions of a unified power quality conditioner. The system can be controlled for current harmonics and reactive power compensation simultaneously by using a converter operating as active shunt filter. The other converter is used as active series filter and it compensates voltage harmonics or voltage sags and swells. Using only an inverter in photovoltaic energy conversion process, the system presents increased efficiency when compared to the conventional systems. The synchronous reference frame method is used to control the three-phase converters. Simulation results demonstrate the good performance of the proposed configuration. Experimental results corresponding to the operation of the series filter as voltage sag compensator are presented.

	Maximum Power Point Tracking Techniques for Photovoltaic Systems By Marcelo Cabral Cavalcanti, Kleber Carneiro de Oliveira, Gustavo Medeiros de Souza Azevedo, Davi Carvalho Moreira, Francisco de Assis dos Santos Neves	[View] [Download]
Abstract: This paper presents a comparative study among maximum power point tracking methods for photovoltaic systems. The comparison takes into account steady state error, dynamic response and efficiency in a large power range. In special, an extensive bibliography and a classification of many maximum power point tracking methods is presented. Computational simulations with fast changes in the solar radiance have been done and the best maximum power point tracking technique is chosen.

	Contactless multipolar doubly-fed asynchronous generator for windmills By N. Levin, V. Pugachov, L. Ribickis, A. Zhiravetska	[View] [Download]
Abstract: A multipolar contactless doubly-fed asynchronous generator is considered where the primary and secondary generation windings are arranged on the teeth of the stator, while the rotor is tooth-like and without windings. Analytical treatment of such a generator has been performed and the basic equations that allow the parameters and performance of the machine to be calculated in generation mode of operation have been obtained. The results of experimental investigations are presented for the physical model of the generator and comparison with the calculation data is given.

	Application of Z-Source Converter in Photovoltaic Grid-Connected Transformer-Less Inverter By Babak Farhangi, Shahrokh Farhangi	[View] [Download]
Abstract: In PV grid connected power conditioners, usually both boosting the PV array voltage, and bucking the dc bus voltage for injection of a sinusoidal current to the grid is required. In this paper the design procedure of Z-source converter as a single phase PV grid connected transformer-less inverter is presented. The converter has one switch less than the conventional two stage power conditioner, which leads to reduction of cost. An optimum modulation pattern for the switches is proposed. The design of the converter is verified by simulation.

	ROBUST FAULT DIAGNOSIS OF A WIND POWER STATION By Wojciech Jarzyna	[View] [Download]
Abstract: The paper presents fault isolation approach of a wind power station based on model-based diagnosis. The main attention is focused on a wind turbine for which the state equation is formulated. Certain faults occurring in described turbine blades are represented by change of equation parameters. The knowledge about the disturbances are obtained from measured and estimated instantaneous angular velocity of the shaft. The desired sensitivity assures applied robust observers, which decouple changes of selected wind engine parameters from computed outputs. Generated residuals allow to isolate a blade elasticity and its oscillation damping and damping of the rotation a drive train.

	Development of Wind Turbine Simulators Using PSCAD By Ahmed Abo-Khalil, Dong-Choon Lee	[View] [Download]
Abstract: In this paper, a wind turbine simulator is developed using PSCAD. The wind turbine static characteristics are modeled using the relation among the turbine power, the wind speed, and the blade pitch angle. Also, the dynamic characteristics of the wind turbine are modeled through a two-mass oscillating system, representing the turbine and the generator connected by elastic shaft. The system considered is designed to show the effects of the tower shadow effect and blades asymmetry. Torsional oscillation effect on the drive train is also considered. A pitch angle controller is used to limit the turbine output power to the rated value to protect the coupled generator. Simulation results are presented to verify the wind turbine simulator performance.

	Transient Current Limitation of the Cage Induction Generator Connected to the Grid By Marcin Grzeczkowicz, Wlodzimierz Koczara, Zbigniew Szulc	[View] [Download]
Abstract: The paper presents a control method of start of a large cage induction motor. The starting process consists of two main states. In the first state a power electronic inverter is used to control the speed and current of accelerating motor. Therefore the grid current is fully controlled and adjusted to references. In the second state the power electronic inverter is off and the motor is connected directly to grid. A method of synchronization of the induced emf. of the motor to the grid voltage reduces transient current and torque jerk. However, relatively long time of the electromechanical transfer switch operation results in displacement of the emf. and increase of the stator current.