EPE Association: EPE 1997 – 39: Dialogue Session DS5n: DESIGN DIAGNOSIS

EPE 1997 – 39: Dialogue Session DS5n: DESIGN DIAGNOSIS
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   ASYMMETRICAL SUPPLY DURING FAULT SITUATIONS IN AN INDUCTION MACHINE DRIVE SYSTEM
By S.G. Bosga; A.J.A. Vandenput [View]
[Download]

Abstract: If a fault a short or open circuit- occurs in the power converter of an induction machine drive system, symmetrical supply of the machine is no longer possible. Depending on the kind of fault and the connection of the star point of the stator windings, continued operation of the drive is possible in some cases. This article presents an overview of the possibilities for remedial operation in case of an open circuit in one of the phases of the machine or the converter.

   ROTOR FAULT DETECTION OF INVERTER FED INDUCTION MACHINES INCLUDING EXPERIMENTAL RESULTS
By Rudolf Wieser; Christian Kral; Franz Pirker; Matthias Schagginger [View]
[Download]

Abstract: This paper suggests a method to monitor defects such as cracked rotor bars in induction machines. Rotor bar faults cause an asymmetric magnetic flux pattern in the air-gap. Thus, the current phasor (or voltage phasor at current controlled machines), the flux phasor and the air-gap torque differ from those of an ideal symmetric machine. The proposed condition monitoring method compares the outputs of a reference model, that represents an ideal machine, to a measurement model. Observing the deviations of these two models makes it possible to detect and even locate rotor faults. It can be applied to inverter fed machines as no frequency analysis is used. The method is verified by on-line experimental results from a DSP-controlled IGBT-inverter drive. The findings match the outcomes of a detailed machine simulation. Air-gap flux density evaluation by a measurement coil system proofs both excellent sensitivity and fault location ability of the proposed scheme.

   A NEW REASON FOR BEARING CURRENT DAMAGES IN VARIABLE SPEED AC DRIVES
By J. Ollila; T. Hammar; J. Iisakkala; H. Tuusa [View]
[Download]

Abstract: This paper introduces the previously known reasons and a new phenomenon causing bearing failures in inverter fed AC-drives. Numerous laboratory tests with a 250 kW induction motor show, that this new phenomenon is dominant with IEC 355 frame size motors. Two easily realisable solutions to eliminate the bearing current problem are proposed.

   DESIGN AND IMPLEMENTATION OF A SINGLE-BOARD MOTOR SUPPLY CONTROLLER
By E. K. H. van der Pols; J. A. J. M. Geerligs [View]
[Download]

Abstract: A single-board motor supply controller has been designed and implemented as part of a modular asynchronous machine drive controller. The controller is based on an MC68332 microcontroller and a FLEX-EPLD. Main functions include vector oriented control and pulse pattern generation. The pulse pattern generator uses Space Vector Modulation and Optimized Angle Modulation as modulation strategies. The modular design with well-defined interfaces enables its use in a wide range of applications.

   ON MEASUREMENTS OF HARMONIC VOLTAGES, CURRENTS AS WELL AS VARIOUS TYPES OF POWERS AND VOLT AMPERES
By Lars Gertmar [View]
[Download]

Abstract: Characteristics of some power engineering signals in variable-speed drives are described. Terminology for non-sinusoidal voltages and currents, and FFT (Fast-Fourier-Transform) signal processing, were expanded in our R&D work on drives for both industry and traction. Solutions of the necessary potential isolation as well as some V-A-W-meters was dealt with. It was recently found that this could be of interest to the public that so far are basing their work on the well-established Fourier-Series analysis and thereby neglecting sub-harmonics as well as interharmonics and some phase shifts. Our experience is that we can rely on modem signal processing with autocorrelation and cross-correlation to define RMS-values, as well as active, reactive and apparent power. The result is a linear method to handle the frequency components of the three power quantities "P", "Q" and" S= P+jQ"- as long as we do not pass through a frequency inverter. RMS-values "IRMs" and "URMs" must on the other hand be handled especially. The Hilbert transform of the current is basically used to define reactive power. The coherence function which is a statistical function of the frequency is a proper quantity to analyze the uncertainties in the three power quantities mentioned above. Furthermore, we found that earlier definitions of apparent power and distortion power are non-stringent while the definitions reported in the paper are in full accordance with the methods implemented in modem dynamic signal analyzers. One should not define S = URMs · IRMs any more for non-sinusoidal systems.

   WINDOWS-APPLICATION FOR OPTIMIZED DESIGNING OF SINGLE-PHASE ASYNCHRONOUS MOTORS
By Gheorghe Scutaru; V. Taropa [View]
[Download]

Abstract: This paper presents a program for the optimized designing of single-phase induction motors, conceived in the VISUAL BASIC language. The program offers its users several facilities, i.e. an accessible interface, the possibility to choose from different ways of formulating the optimum problem, an up-datable data base including information on the characteristics of the materials used and the manufactured motors.

   OPTIMIZED DESIGN OF VARIABLE-SPEED DRIVES BASED ON NUMERICAL SIMULATION
By J.-J. Simond; A. Sapin; B. Kawkabani; D. Schafer; M. Tu Xuan; B. Willy [View]
[Download]

Abstract: The proposed paper describes the modelling and the prediction of the steadystate or transient behaviour of different modern variable-speed drives. The necessity of a performant numerical simulation tool in order to guarantee an optimized design is illustrated by examples based on existing large variable-speed drives.

   DESIGN OF A DOUBLE FED A.C. MACHINE FOR HIGH SPEED RANGE APPLICATIONS
By J-R. Hadji-Minaglou; Philippe Lataire; H. Godfroid; D. Lecocq; A. Mirzaïan [View]
[Download]

Abstract: The double fed A.C. motor with wound rotor (DFAM) is suitable for dynamic high power industrial applications which require a wide "constant power" speed range involving deep field weakening. The considered drives are sized for 250 till 5000 kW industrial applications which require constant power operation in a speed range ratio up to 1 to 6. By supplying its rotor and its stator with separate converters, a DFAM is able to reach these specifications with minor motor and power electronics converters oversizing, while a squirrel cage induction motor needs significant motor and power electronics converter oversizing. Besides, with a lower voltage and current reserve on both converters the drive offers a higher dynamic and faster flux -weakening - rebuilding cycles because of absence of damping squirrel cage or damping windings.

EPE 1997 – 39: Dialogue Session DS5n: DESIGN DIAGNOSIS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 39: Dialogue Session DS5n: DESIGN DIAGNOSIS
	[return to parent folder]

	ASYMMETRICAL SUPPLY DURING FAULT SITUATIONS IN AN INDUCTION MACHINE DRIVE SYSTEM By S.G. Bosga; A.J.A. Vandenput	[View] [Download]
Abstract: If a fault a short or open circuit- occurs in the power converter of an induction machine drive system, symmetrical supply of the machine is no longer possible. Depending on the kind of fault and the connection of the star point of the stator windings, continued operation of the drive is possible in some cases. This article presents an overview of the possibilities for remedial operation in case of an open circuit in one of the phases of the machine or the converter.

	ROTOR FAULT DETECTION OF INVERTER FED INDUCTION MACHINES INCLUDING EXPERIMENTAL RESULTS By Rudolf Wieser; Christian Kral; Franz Pirker; Matthias Schagginger	[View] [Download]
Abstract: This paper suggests a method to monitor defects such as cracked rotor bars in induction machines. Rotor bar faults cause an asymmetric magnetic flux pattern in the air-gap. Thus, the current phasor (or voltage phasor at current controlled machines), the flux phasor and the air-gap torque differ from those of an ideal symmetric machine. The proposed condition monitoring method compares the outputs of a reference model, that represents an ideal machine, to a measurement model. Observing the deviations of these two models makes it possible to detect and even locate rotor faults. It can be applied to inverter fed machines as no frequency analysis is used. The method is verified by on-line experimental results from a DSP-controlled IGBT-inverter drive. The findings match the outcomes of a detailed machine simulation. Air-gap flux density evaluation by a measurement coil system proofs both excellent sensitivity and fault location ability of the proposed scheme.

	A NEW REASON FOR BEARING CURRENT DAMAGES IN VARIABLE SPEED AC DRIVES By J. Ollila; T. Hammar; J. Iisakkala; H. Tuusa	[View] [Download]
Abstract: This paper introduces the previously known reasons and a new phenomenon causing bearing failures in inverter fed AC-drives. Numerous laboratory tests with a 250 kW induction motor show, that this new phenomenon is dominant with IEC 355 frame size motors. Two easily realisable solutions to eliminate the bearing current problem are proposed.

	DESIGN AND IMPLEMENTATION OF A SINGLE-BOARD MOTOR SUPPLY CONTROLLER By E. K. H. van der Pols; J. A. J. M. Geerligs	[View] [Download]
Abstract: A single-board motor supply controller has been designed and implemented as part of a modular asynchronous machine drive controller. The controller is based on an MC68332 microcontroller and a FLEX-EPLD. Main functions include vector oriented control and pulse pattern generation. The pulse pattern generator uses Space Vector Modulation and Optimized Angle Modulation as modulation strategies. The modular design with well-defined interfaces enables its use in a wide range of applications.

	ON MEASUREMENTS OF HARMONIC VOLTAGES, CURRENTS AS WELL AS VARIOUS TYPES OF POWERS AND VOLT AMPERES By Lars Gertmar	[View] [Download]
Abstract: Characteristics of some power engineering signals in variable-speed drives are described. Terminology for non-sinusoidal voltages and currents, and FFT (Fast-Fourier-Transform) signal processing, were expanded in our R&D work on drives for both industry and traction. Solutions of the necessary potential isolation as well as some V-A-W-meters was dealt with. It was recently found that this could be of interest to the public that so far are basing their work on the well-established Fourier-Series analysis and thereby neglecting sub-harmonics as well as interharmonics and some phase shifts. Our experience is that we can rely on modem signal processing with autocorrelation and cross-correlation to define RMS-values, as well as active, reactive and apparent power. The result is a linear method to handle the frequency components of the three power quantities "P", "Q" and" S= P+jQ"- as long as we do not pass through a frequency inverter. RMS-values "IRMs" and "URMs" must on the other hand be handled especially. The Hilbert transform of the current is basically used to define reactive power. The coherence function which is a statistical function of the frequency is a proper quantity to analyze the uncertainties in the three power quantities mentioned above. Furthermore, we found that earlier definitions of apparent power and distortion power are non-stringent while the definitions reported in the paper are in full accordance with the methods implemented in modem dynamic signal analyzers. One should not define S = URMs · IRMs any more for non-sinusoidal systems.

	WINDOWS-APPLICATION FOR OPTIMIZED DESIGNING OF SINGLE-PHASE ASYNCHRONOUS MOTORS By Gheorghe Scutaru; V. Taropa	[View] [Download]
Abstract: This paper presents a program for the optimized designing of single-phase induction motors, conceived in the VISUAL BASIC language. The program offers its users several facilities, i.e. an accessible interface, the possibility to choose from different ways of formulating the optimum problem, an up-datable data base including information on the characteristics of the materials used and the manufactured motors.

	OPTIMIZED DESIGN OF VARIABLE-SPEED DRIVES BASED ON NUMERICAL SIMULATION By J.-J. Simond; A. Sapin; B. Kawkabani; D. Schafer; M. Tu Xuan; B. Willy	[View] [Download]
Abstract: The proposed paper describes the modelling and the prediction of the steadystate or transient behaviour of different modern variable-speed drives. The necessity of a performant numerical simulation tool in order to guarantee an optimized design is illustrated by examples based on existing large variable-speed drives.

	DESIGN OF A DOUBLE FED A.C. MACHINE FOR HIGH SPEED RANGE APPLICATIONS By J-R. Hadji-Minaglou; Philippe Lataire; H. Godfroid; D. Lecocq; A. Mirzaïan	[View] [Download]
Abstract: The double fed A.C. motor with wound rotor (DFAM) is suitable for dynamic high power industrial applications which require a wide "constant power" speed range involving deep field weakening. The considered drives are sized for 250 till 5000 kW industrial applications which require constant power operation in a speed range ratio up to 1 to 6. By supplying its rotor and its stator with separate converters, a DFAM is able to reach these specifications with minor motor and power electronics converters oversizing, while a squirrel cage induction motor needs significant motor and power electronics converter oversizing. Besides, with a lower voltage and current reserve on both converters the drive offers a higher dynamic and faster flux -weakening - rebuilding cycles because of absence of damping squirrel cage or damping windings.