EPE Association: EPE 2003 - Topic 09h: Modelling and Simulation

EPE 2003 - Topic 09h: Modelling and Simulation
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2003 - Conference > EPE 2003 - Topic 09: ELECTRICAL MACHINES AND ADJUSTABLE SPEED DRIVES > EPE 2003 - Topic 09h: Modelling and Simulation

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   A study of the acoustical properties of stators with an outer-surface layer of air gaps
By D. Martinez-Muñoz; J.C.S. Lai; M. Alaküla [View]
[Download]

Abstract: A layer of air gaps has been included along the periphery of a conventional stator structure in order to isolate the outer surface and reduce the noise emissions. The feasibility of this idea has been assessed using structural FEM and acoustic BEM simulations. Results using different gap geometries show that the overall acoustic behaviour of the new structures is not improved. On one hand, the stiffness of the structure is reduced where the air gaps are introduced, since iron material is replaced by air. On the other hand, it is shown that the vibrations are also transmitted through the air in the gaps, providing less acoustic isolation than expected. These results, supported by experimental measurements of a prototype motor based on the air gap concept, demonstrate that modern computational tools can be used to assess the effectiveness of innovative ideas on the design of ‘quiet’ motors.

   Modelling and simulation of DTC induction motor drives for stator winding faults diagnosis
By S.M.A. Cruz; A.J.M. Cardoso [View]
[Download]

Abstract: In this paper a new mathematical model of a three-phase squirrel-cage induction motor for stator winding faults diagnosis is presented, allowing the simulation of line-fed and DTC inverter-fed induction motors. Different stator winding configurations are studied and it is shown how the winding arrangement influences the diagnosis of faults in the stator windings of the motor. Simulation and experimental results emphasize the problems inherent to the diagnosis of stator winding faults for the case of line-fed and DTC inverter-fed induction machines.

   Modelling multiple saliencies in rotor-faulty induction machine for rotor position estimation
By I. Al-Rouh; L. Baghli; A. Rezzoug [View]
[Download]

Abstract: This paper presents an approach to estimate the position of the rotor of an induction machine. The applied method is based on the injection of a carrier signal in addition to the fundamental excitation. The least square algorithm is proposed for the estimation of the multiple saliencies model. This model will be implemented in a tracking observer to estimate the rotor position.

   A high frequency model of electric motor used for high speed switching applications
By F. Zare [View]
[Download]

Abstract: In a motor drive system, a voltage source converter with hard switches generate high dv/dt, which causes leakage currents due to stray capacitances of an electric motor. A high frequency model of an electric motor is an important issue for power electronic engineers, which helps them to analyze leakage and bearing currents and to design EMI filters. At low frequency, an equivalent circuit of an electric motor consists of inductances and resistances without considering stray capacitances and skin effect. These issues become more important at high frequency particularly for high speed switching applications due to high dv/dt. This paper presents a simple method to extract high frequency parameters of an electric motor. An impedance of a 5.5KW motor has been measured in terms of frequency using an impedance analyzer and the results have been used to extract high frequency parameters. It is recommended to estimate the behavior of the motor in a frequency range, when the motor acts as a capacitive or an inductive load according to the phase values of the impedance. Then, the parameters can be calculated directly from the magnitude and the phase values of the impedance. A simple model of an electric motor at high frequency used for high speed switching applications is discussed in this research work.

   Debugging of microprocessor-based control systems of electric drives when using the mathematical models
By B.Z. Drobkin; A.G. Vorontsov; M.V. Pronin; Y.A. Krutyakov; P.A. Pavlov [View]
[Download]

Abstract: Normally, control devices for powerful electric drives and other electric installations are debugged at operating plants and it is connected with substantial expenditures of time and other resources. Mathematical models of an installation power part, plotted with the help of computers, operating in real-time mode, are used in the developed system to debug microproc-essor-based control units with frequency thyristor converters and synchronous motors.

   Modelling electromechanical actuators for simulation: MAEL performs model capitalization and symbolic treatment
By L. Allain; L. Gerbaud; C. Van Der Schaeghe [View]
[Download]

Abstract: The paper presents an approach for the development of models used by engineers in the design process of electromechanical actuators, specifically in simulation. This method embeds a tool that helps the designer into the task of describing and programming models for several simulation environments. Firstly, the paper proposes to capitalize models under a non oriented shape. Secondly, it proposes to combine and to orient models as white boxes, by re-organising their equations and algorithms according to their use context. The paper proposes to automate this task, taking into account the specificities of the simulation processes. This results in a dedicated solving process for each model treatment. Finally, the paper proposes the automatic translation of the oriented model into specific code for simulation tools. This results in a modelling approach that allows a whole reusability of the specific developed models. The models are capitalized under a structured shape and are changed according to their use context and the tool where they are programmed.

   Analysis of reduced order models for large squirrel-cage induction generators in wind turbine applications
By F. Iov; F. Blaabjerg; A.-D. Hansen; P. Sørensen [View]
[Download]

Abstract: The aim of this paper is to analyze which reduced order model of the squirrel-cage induction generator is suitable in the advanced aerodynamic simulation tools used to simulate mechanical loads on wind turbines. The aero elastic codes focus on the frequency scale 0 –20 Hz, because the main contribution to fatigue loads is in this frequency range. Three models of induction machine are considered in the analysis the complete dynamic model, the reduced order model, which neglects the stator transients and the steady-state model. All these models are analyzed in two cases: a one-mass model and the two-mass model of the wind turbine drive train. Using linear system theory the eigenvalues and the frequency response for both approaches are presented. Some simulations regarding the response of the considered models during start-up, fault condition as well as under a given wind profile, are shown. Moreover, the harmonic spectra for torque and stator active power are presented.

   Two approaches to modelling of switched reluctance drives
By A. Matveev; V. Kuzmichev; R. Nilssen; T. Undeland [View]
[Download]

Abstract: The paper presents two approaches for modelling of the electromagnetic processes in switched reluctance drives (SRD). The main attention is focused on the original techniques for building the models in MATLAB/SIMULINK™ and FLUX2D/3D. The experimental verification of the models is done. The comparison of the models is presented in the paper.

   Analytic model of automotive claw-pole alternator for design and constrained optimisation
By L. Albert; C. Chillet; A. Jarosz; F. Wurtz [View]
[Download]

Abstract: Most of car alternators are claw-pole synchronous machines with poor efficiency. A Claw-pole alternator computer design strategy is presented in this paper. First, a model based on magnetic equivalent circuit and first harmonic electric scheme is established. Then, initial volume remaining constant, this model is implemented into an optimisation software to improve the alternator efficiency.

   Saturation in asynchronous machines due to voltage sags
By F. Carlsson [View]
[Download]

Abstract: Voltage sags and voltage interruptions are huge power quality problems for many industries. Voltage sags cause tripping of asynchronous machines by undervoltage or overcurrent protection and in some cases saturation of the flux. This paper gives a basic understanding of how voltage sags change the stator flux in line-operated asynchronous machines and under which circumstances saturation will occur. Most voltage sags will cause saturation. Flux saturation results in both large currents and torque; these may fasten the aging of the machine.

   Detection of broken rotor bars under periodic load conditions by using a high frequency test signal in one stator phase
By A. Piñol; J. A. Ortega; J.-L. Romeral [View]
[Download]

Abstract: Motor Current Signature Analysis has been successfully used in induction machine fault diagnosis. However this method does not always achieve good results when the load torque is not constant but depending of the rotation angle. This paper presents a way to remedy the situation by using a high frequency test signal in one stator phase and analyzing the current spectrum, around the test frequency, in this phase.

   Particle swarm and genetic algorithms applied to the identification of induction machine parameters
By L. Baghli; A. Rezzoug. [View]
[Download]

Abstract: This paper deals with the identification of induction machine parameters using Genetic Algorithms (GA) and Particle Swarm Optimisation (PSO) method. Thanks to these algorithms, optimisation is carried without the evaluation of the gradient. The optimisation is carried using current and speed experimental curves of a direct start-up. Convergence speed, algorithms tuning and local-minima problems are discussed. Results during the evolution process are presented as well as a comparison with the experimental results.

   Analytical, 2D FEM and 3D FEM modelling of axial flux PM machines
By A. Parviainen; M. Niemelä; J. Pyrhönen [View]
[Download]

Abstract: This paper gives an overview on different modelling methods of axial flux surface mounted permanent magnet machines. Due to the inherent 3D geometry of axial flux machines, the reduction of the design problem to a 2D plane on the average radius of the machine does not yield to accurate computation results in cases in which the magnet shape is complex. Particularly, the obtained curvatures and peak values of torque and back-EMF may be strongly erroneous. A practical accuracy can be achieved in those computations also by using quasi-3D computation method with analytical or 2D finite element models. The most accurate method to predict the performance of axial flux machine is a real 3D FEM modelling, but as a drawback it is often too time consuming to perform. This limits its efficient use in daily design work. In this paper an overview to the different design methods and their applicability in a design of axial flux surface mounted permanent magnet machines is presented.

   Simulation of electric drive systems with coupled finite element analysis and system simulator
By S. Kanerva; S. Seman; A. Arkkio [View]
[Download]

Abstract: This paper presents simulation software for electric drives including an electrical machine, frequency converter and its control system. Finite element method (FEM) model of an electrical machine is coupled with Simulink by an S-function, which provides a functional block performing the FEM calculation in time stepping procedure. With this software, an induction motor drive with direct torque control (DTC) is modeled and simulated. The phase currents of the induction motor are determined by FEM and used for calculating the estimates for stator flux and torque in the DTC inverter. Both stator flux linkages and electromagnetic torque of the induction motor are also determined from the FEM solution and compared with the estimated values obtained from a simple flux and torque estimator. In steady state, the simple estimates and the values calculated by FEM agree very well, but some difference is detected in transient operation. The results show effects that can be modeled by FEM but are not covered in the models based on equivalent circuit approach. It is shown that coupling of the FEM calculation with Simulink gives detailed information about the interaction between the electrical machine, inverter and control system. Because of this, the software can be used as an advanced tool for electric drive design.

   An improved model of induction machines for accurate predictions of wind generator line short circuit currents
By M. Helmer; T. Thiringer [View]
[Download]

Abstract: This paper presents an advanced model of the induction machine for accurate prediction of the fault current contribution due to line short circuits. The model is suitable for transient as well as for steady state operation analysis. The proposed model takes the skin effect in the rotor conductors and the effects of the leakage flux path saturation into account. It is experimentally verified using a six pole; 15kW squirrel cage induction machine. Measurements of a start, a three phase short circuit and a locked rotor test are compared with simulations, which show excellent agreements.

EPE 2003 - Topic 09h: Modelling and Simulation
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2003 - Conference > EPE 2003 - Topic 09: ELECTRICAL MACHINES AND ADJUSTABLE SPEED DRIVES > EPE 2003 - Topic 09h: Modelling and Simulation
	[return to parent folder]

	A study of the acoustical properties of stators with an outer-surface layer of air gaps By D. Martinez-Muñoz; J.C.S. Lai; M. Alaküla	[View] [Download]
Abstract: A layer of air gaps has been included along the periphery of a conventional stator structure in order to isolate the outer surface and reduce the noise emissions. The feasibility of this idea has been assessed using structural FEM and acoustic BEM simulations. Results using different gap geometries show that the overall acoustic behaviour of the new structures is not improved. On one hand, the stiffness of the structure is reduced where the air gaps are introduced, since iron material is replaced by air. On the other hand, it is shown that the vibrations are also transmitted through the air in the gaps, providing less acoustic isolation than expected. These results, supported by experimental measurements of a prototype motor based on the air gap concept, demonstrate that modern computational tools can be used to assess the effectiveness of innovative ideas on the design of ‘quiet’ motors.

	Modelling and simulation of DTC induction motor drives for stator winding faults diagnosis By S.M.A. Cruz; A.J.M. Cardoso	[View] [Download]
Abstract: In this paper a new mathematical model of a three-phase squirrel-cage induction motor for stator winding faults diagnosis is presented, allowing the simulation of line-fed and DTC inverter-fed induction motors. Different stator winding configurations are studied and it is shown how the winding arrangement influences the diagnosis of faults in the stator windings of the motor. Simulation and experimental results emphasize the problems inherent to the diagnosis of stator winding faults for the case of line-fed and DTC inverter-fed induction machines.

	Modelling multiple saliencies in rotor-faulty induction machine for rotor position estimation By I. Al-Rouh; L. Baghli; A. Rezzoug	[View] [Download]
Abstract: This paper presents an approach to estimate the position of the rotor of an induction machine. The applied method is based on the injection of a carrier signal in addition to the fundamental excitation. The least square algorithm is proposed for the estimation of the multiple saliencies model. This model will be implemented in a tracking observer to estimate the rotor position.

	A high frequency model of electric motor used for high speed switching applications By F. Zare	[View] [Download]
Abstract: In a motor drive system, a voltage source converter with hard switches generate high dv/dt, which causes leakage currents due to stray capacitances of an electric motor. A high frequency model of an electric motor is an important issue for power electronic engineers, which helps them to analyze leakage and bearing currents and to design EMI filters. At low frequency, an equivalent circuit of an electric motor consists of inductances and resistances without considering stray capacitances and skin effect. These issues become more important at high frequency particularly for high speed switching applications due to high dv/dt. This paper presents a simple method to extract high frequency parameters of an electric motor. An impedance of a 5.5KW motor has been measured in terms of frequency using an impedance analyzer and the results have been used to extract high frequency parameters. It is recommended to estimate the behavior of the motor in a frequency range, when the motor acts as a capacitive or an inductive load according to the phase values of the impedance. Then, the parameters can be calculated directly from the magnitude and the phase values of the impedance. A simple model of an electric motor at high frequency used for high speed switching applications is discussed in this research work.

	Debugging of microprocessor-based control systems of electric drives when using the mathematical models By B.Z. Drobkin; A.G. Vorontsov; M.V. Pronin; Y.A. Krutyakov; P.A. Pavlov	[View] [Download]
Abstract: Normally, control devices for powerful electric drives and other electric installations are debugged at operating plants and it is connected with substantial expenditures of time and other resources. Mathematical models of an installation power part, plotted with the help of computers, operating in real-time mode, are used in the developed system to debug microproc-essor-based control units with frequency thyristor converters and synchronous motors.

	Modelling electromechanical actuators for simulation: MAEL performs model capitalization and symbolic treatment By L. Allain; L. Gerbaud; C. Van Der Schaeghe	[View] [Download]
Abstract: The paper presents an approach for the development of models used by engineers in the design process of electromechanical actuators, specifically in simulation. This method embeds a tool that helps the designer into the task of describing and programming models for several simulation environments. Firstly, the paper proposes to capitalize models under a non oriented shape. Secondly, it proposes to combine and to orient models as white boxes, by re-organising their equations and algorithms according to their use context. The paper proposes to automate this task, taking into account the specificities of the simulation processes. This results in a dedicated solving process for each model treatment. Finally, the paper proposes the automatic translation of the oriented model into specific code for simulation tools. This results in a modelling approach that allows a whole reusability of the specific developed models. The models are capitalized under a structured shape and are changed according to their use context and the tool where they are programmed.

	Analysis of reduced order models for large squirrel-cage induction generators in wind turbine applications By F. Iov; F. Blaabjerg; A.-D. Hansen; P. Sørensen	[View] [Download]
Abstract: The aim of this paper is to analyze which reduced order model of the squirrel-cage induction generator is suitable in the advanced aerodynamic simulation tools used to simulate mechanical loads on wind turbines. The aero elastic codes focus on the frequency scale 0 –20 Hz, because the main contribution to fatigue loads is in this frequency range. Three models of induction machine are considered in the analysis the complete dynamic model, the reduced order model, which neglects the stator transients and the steady-state model. All these models are analyzed in two cases: a one-mass model and the two-mass model of the wind turbine drive train. Using linear system theory the eigenvalues and the frequency response for both approaches are presented. Some simulations regarding the response of the considered models during start-up, fault condition as well as under a given wind profile, are shown. Moreover, the harmonic spectra for torque and stator active power are presented.

	Two approaches to modelling of switched reluctance drives By A. Matveev; V. Kuzmichev; R. Nilssen; T. Undeland	[View] [Download]
Abstract: The paper presents two approaches for modelling of the electromagnetic processes in switched reluctance drives (SRD). The main attention is focused on the original techniques for building the models in MATLAB/SIMULINK™ and FLUX2D/3D. The experimental verification of the models is done. The comparison of the models is presented in the paper.

	Analytic model of automotive claw-pole alternator for design and constrained optimisation By L. Albert; C. Chillet; A. Jarosz; F. Wurtz	[View] [Download]
Abstract: Most of car alternators are claw-pole synchronous machines with poor efficiency. A Claw-pole alternator computer design strategy is presented in this paper. First, a model based on magnetic equivalent circuit and first harmonic electric scheme is established. Then, initial volume remaining constant, this model is implemented into an optimisation software to improve the alternator efficiency.

	Saturation in asynchronous machines due to voltage sags By F. Carlsson	[View] [Download]
Abstract: Voltage sags and voltage interruptions are huge power quality problems for many industries. Voltage sags cause tripping of asynchronous machines by undervoltage or overcurrent protection and in some cases saturation of the flux. This paper gives a basic understanding of how voltage sags change the stator flux in line-operated asynchronous machines and under which circumstances saturation will occur. Most voltage sags will cause saturation. Flux saturation results in both large currents and torque; these may fasten the aging of the machine.

	Detection of broken rotor bars under periodic load conditions by using a high frequency test signal in one stator phase By A. Piñol; J. A. Ortega; J.-L. Romeral	[View] [Download]
Abstract: Motor Current Signature Analysis has been successfully used in induction machine fault diagnosis. However this method does not always achieve good results when the load torque is not constant but depending of the rotation angle. This paper presents a way to remedy the situation by using a high frequency test signal in one stator phase and analyzing the current spectrum, around the test frequency, in this phase.

	Particle swarm and genetic algorithms applied to the identification of induction machine parameters By L. Baghli; A. Rezzoug.	[View] [Download]
Abstract: This paper deals with the identification of induction machine parameters using Genetic Algorithms (GA) and Particle Swarm Optimisation (PSO) method. Thanks to these algorithms, optimisation is carried without the evaluation of the gradient. The optimisation is carried using current and speed experimental curves of a direct start-up. Convergence speed, algorithms tuning and local-minima problems are discussed. Results during the evolution process are presented as well as a comparison with the experimental results.

	Analytical, 2D FEM and 3D FEM modelling of axial flux PM machines By A. Parviainen; M. Niemelä; J. Pyrhönen	[View] [Download]
Abstract: This paper gives an overview on different modelling methods of axial flux surface mounted permanent magnet machines. Due to the inherent 3D geometry of axial flux machines, the reduction of the design problem to a 2D plane on the average radius of the machine does not yield to accurate computation results in cases in which the magnet shape is complex. Particularly, the obtained curvatures and peak values of torque and back-EMF may be strongly erroneous. A practical accuracy can be achieved in those computations also by using quasi-3D computation method with analytical or 2D finite element models. The most accurate method to predict the performance of axial flux machine is a real 3D FEM modelling, but as a drawback it is often too time consuming to perform. This limits its efficient use in daily design work. In this paper an overview to the different design methods and their applicability in a design of axial flux surface mounted permanent magnet machines is presented.

	Simulation of electric drive systems with coupled finite element analysis and system simulator By S. Kanerva; S. Seman; A. Arkkio	[View] [Download]
Abstract: This paper presents simulation software for electric drives including an electrical machine, frequency converter and its control system. Finite element method (FEM) model of an electrical machine is coupled with Simulink by an S-function, which provides a functional block performing the FEM calculation in time stepping procedure. With this software, an induction motor drive with direct torque control (DTC) is modeled and simulated. The phase currents of the induction motor are determined by FEM and used for calculating the estimates for stator flux and torque in the DTC inverter. Both stator flux linkages and electromagnetic torque of the induction motor are also determined from the FEM solution and compared with the estimated values obtained from a simple flux and torque estimator. In steady state, the simple estimates and the values calculated by FEM agree very well, but some difference is detected in transient operation. The results show effects that can be modeled by FEM but are not covered in the models based on equivalent circuit approach. It is shown that coupling of the FEM calculation with Simulink gives detailed information about the interaction between the electrical machine, inverter and control system. Because of this, the software can be used as an advanced tool for electric drive design.

	An improved model of induction machines for accurate predictions of wind generator line short circuit currents By M. Helmer; T. Thiringer	[View] [Download]
Abstract: This paper presents an advanced model of the induction machine for accurate prediction of the fault current contribution due to line short circuits. The model is suitable for transient as well as for steady state operation analysis. The proposed model takes the skin effect in the rotor conductors and the effects of the leakage flux path saturation into account. It is experimentally verified using a six pole; 15kW squirrel cage induction machine. Measurements of a start, a three phase short circuit and a locked rotor test are compared with simulations, which show excellent agreements.