EPE Association: EPE 2003 - Topic 09f: Converter Machine Interactions

EPE 2003 - Topic 09f: Converter Machine Interactions
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 09f: Converter Machine Interactions

   [return to parent folder]

   High frequency stator ground currents of inverter-fed squirrel-cage induction motors up to 500 kW
By A. Muetze; A. Binder [View]
[Download]

Abstract: One type of bearing currents that occur at inverter-operation is the high frequency circulating bearing current. This current is induced by the high frequency stator ground current of the motor. Such stator ground currents have been investigated within a research program for systematic investigation of the influence of different system parameters on inverter-induced bearing currents on power levels 11 kW to 500 kW. This paper discusses the influence of motor size, motor-inverter-combination, motor cable type and length and passive filters on the high frequency stator ground currents.

   Comparison of natural sampling and random PWM control strategy for reducing acoustic noise
By V. Lanfranchi; A. Hubert; G. Friedrich [View]
[Download]

Abstract: This paper compares the vibratory responses of a well-known mechanical free response stator with two PWM strategies (natural sampling and random) implemented on a TMS320F240 DSP. The presented results are discussed as well as on vibratory response and computing DSP time, for similar THD current, for the two PWM controls in load and no load conditions.

   Performance comparison of different output filter topologies for adjustable speed drives
By N. Hanigovszki; J. Poulsen; F. Blaabjerg [View]
[Download]

Abstract: This paper presents a comparison between four different output filter topologies for PWM adjustable speed drives (ASD): choke filter, LC filter, input/output LC filter and filter with return of common mode components to the DC link. The filters are placed between the inverter and the motor cable. Both electromagnetic compatibility (EMC) aspects and machine stress due to high dv/dt values are evaluated. A novel method is used for evaluating output common-mode noise. The paper concludes that there is a trade-off between output filter performance and complexity, as all filters reduce electromagnetic interference (EMI), but only some topologies significantly reduce motor stress.

   Reduction of interference currents in DC traction inverter drives using the highly dynamic torque control
By K. Würflinger; C. Foerth; A. Steimel [View]
[Download]

Abstract: In order to eliminate interference currents up to 120 Hz from the dc-line current of traction drives, the existing highly dynamic torque control (Siemens Traction Control - SITRAC [1]) is used. No extra hardware is needed and the control system structure keeps clearly arranged.

   Modelling EMI in PWM inverter-fed AC motor drive systems
By C. Vermaelen; F. Costa [View]
[Download]

Abstract: The broad utilisation of PWM inverter-fed variable speed drive in the industrial sector has quickly shown radiated and conducted electromagnetic interference (EMI) problems linked to that kind of supply. In an introduction the different sources and specific couplings of these systems will be presented, then the experimental bench, which allowed us to study the various propagation ways and to measure the various impedances of the AC motor will be described. Thus, this paper explains the working out of a model of these systems. In addition, the identification methods used to achieve the models of the different parts of the system will be examined. Furthermore SPICE models are proposed. Finally the experimental validation of models is discussed.

   Active Power-Factor-Correction has remarkable technical advantages
By B. Fuld [View]
[Download]

Abstract: The use of active PFC-circuits should not only be discussed under the aspect of fulfilling normative requirements; it also could help to increase the power of electrical machines in the fieldweakeningrange and to solve the problem of high harmonic currents in the neutral-line, when using a lot of units with single-phase rectifiers. The cost for power-supply installations can be reduced due to the improved power factor. The increased utilization of electrical machines can be reached with active power factor correction circuits based on the boost principle; some known solutions either for single phase and for three phase connection are presented and their specific advantages discussed. Future improvements could be the realised with SiC-diodes and synchronous rectifying.

   Quantification of homopolar components in machines connected to Branch-Delta type soft-starters
By D. W. J. Pulle; A. Veltman [View]
[Download]

Abstract: This paper considers the homopolar components which occur in induction machine/branch-delta softstarters combinations.An extension to an ‘ideal rotating transformer’ based transient machine model is introduced to accommodate homopolar components.Results given conﬁrm the presence of a substantial homopolar ﬂux component in the machine.

   Torque ripple in DTC PMSM drives due to nonlinearity of current sensors
By L. Laurila; J. Pyrhönen; M. Niemelä [View]
[Download]

Abstract: Nonlinear current measurement errors producing torque ripple in direct torque controlled (DTC) permanent magnet synchronous motor (PMSM) drives are analysed. In this paper the focus is on the nonlinearity of Hall-effect current sensors and its effect on torque ripple. It is demonstrated that nonlinear current measurement errors produce harmonics in the torque.

   Comparative experimental analysis of the effects produced by PWM voltage and current source inverter on a low power induction motor
By P. Cancelliere; V. Delli Colli; F. Marignetti; R. Di Stefano [View]
[Download]

Abstract: The paper analyses the performances of a current source inverter with voltage-controlled current modulation, feeding a three-phase induction motor. The discussed current source inverter is fed by a diode rectifier through a current controlled step-down converter. The investigation is conducted by means of an experimental comparison between the proposed inverter and the well-known voltage source inverter drive. Three aspects have been pointed out: harmonic losses, insulation stress, common mode phenomena. The power lost in the induction motor as well as in both inverters has been measured in several steady-state operating conditions. The voltage stress generated by the switching on the motor windings has been recorded for both system under consideration. Finally, the common mode voltage applied to the motor, as well as the circulating common current have been assessed; moreover, the shaft voltage produced by the switching converter operation has been analysed. Aim of the paper is the evaluation of the potential benefits achievable by a current source inverter with a small power induction motor.

   Rotor cage losses of an inverter-fed PMSM investigated with FEM
By P. Thelin; H.-P. Nee; J. Soulard; C. Sadarangani; J. Timmerman [View]
[Download]

Abstract: In the design of a compact inverter-fed buried permanent magnet synchronous motor, the high-frequency losses of the sparse rotor cage - which are difficult to predict - were assumed to be small. To investigate these ohmic high-frequency losses of the rotor cage, fixed-speed time-stepping 2DFEM calculations have been carried out. The losses due to only the magnets, magnets and sinusoidal currents, high-frequency currents etc., and the actual currents are presented. The actual current wave-forms were obtained from measurements on the manufactured prototype motor.

   A new model to analyze the impact of inverter supply voltage and cable length on adjustable speed drive motors
By S. Amarir; K. AL-Haddad; V. Rajagopalan [View]
[Download]

Abstract: The authors present a new model to evaluate the over-voltages caused partially by the length of the cables feeding motors driven by PWM-controlled inverters. Using the mobile waves theory, a full mathematical formula describing the evolution of the transient voltage at the motor terminals was developed. It takes into account all the parameters on which over-voltages depend in the ASD-motor systems, particularly the cable length, as well as the inverter output voltage rise and fall times. The proposed model, based on this mathematical formula, allows the coordination between the ASD-Motor systems and the length of their feeding cables. The model is validated by simulation, using Matlab/Simulink software, and by experimental results.

   Polynomial and neural methods for characterization and diagnostic of a converter fed synchronous machine
By O. Curea; B. Dakyo; G. Barakat [View]
[Download]

Abstract: For the fault detection and the diagnosis, it is useful to have a behavior model of the actual system. A converter fed permanent magnet synchronous machine is used for experimental purpose. The acquisition system is based on the two wattmeter principle, so two voltages and two currents are measured on the three phase side. The representations of the behavior will be chosen simple and relevant for a diagnosis procedure. A polynomial and a neural network approximation for characterization will be presented and compared. For the instant these models work on a personal computer, but is foreseeable a real-time implementation.

   Multi-inverter PWM control: a new generation drive for cruise ship electric propulsion
By S. Siala; E. Guette; J. L. Pouliquen [View]
[Download]

Abstract: This paper presents a new generation of ship electric propulsion based on a double star synchronous machine supplied by two P.W.M. I.G.B.T. inverters. The proposed modeling and control allows separating the dynamic modes of the system and keeps the two basic control functions apart: torque control and current balancing. This new electric propulsion has been validated on a two-poded cruise ship with 20MW propulsion power.

   Cable modelling for electrical drives
By E. Gubía; P. Sanchis; Ó. Alonso; J. López; A. Lumbreras; L. Marroyo [View]
[Download]

Abstract: Technological improvements in power semiconductors have made possible an important increase both in the switching frequency and in the rated power of the adjustable speed drives (ASD) used in electrical drives. As a drawback, ASD generate pulsed-output voltages with a high rate of voltage rise (dv/dt) that can be greater than 5000V/µs. These dv/dt can cause problems in other elements of the system: premature aging of the machine insulation, bearings deterioration, and EMI. Besides, dv/dt and the output voltage amplitude at motor terminals can increase as a consequence of the stray elements of the cable. In order to deal with these adverse effects, new models are needed that incorporate the high-frequency behaviour of cable elements. In this paper, a generic model for the power cable is proposed to study the low- and high-frequency behaviour of currents and voltages in three-phase drives. With this model, the cables that are used at present can be analysed. In addition, an experimental technique is proposed to calculate model parameters that is based on the operation mode of the electrical drive. The model has been validated for the three most common types of cables: unshielded, with external shield or armour, and shielded conductors.

   A few models of iron loss in the AC machines and transformers due to the harmonics
By R. Muszynski [View]
[Download]

Abstract: In the paper a few models for calculation of iron loss in the AC machines and transformers at nonsinusoidal feeding are presented. The differences between the models relate to their form (analytical, simulation), mode of feeding (voltage, current) and to the assumed simplifications, which have effect for the accuracy and frequency range of application. The simplest model has the form of analytical formula, the most compound one reproduces the saturation, hysteresis and eddy current phenomena. In the paper there is description of the separate models and comparison of high harmonic losses obtained with the aid of them for feeding from the voltage as well as current source inverter. There are also given conclusions related to the range of application of the separate models.

EPE 2003 - Topic 09f: Converter Machine Interactions
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 09f: Converter Machine Interactions
	[return to parent folder]

	High frequency stator ground currents of inverter-fed squirrel-cage induction motors up to 500 kW By A. Muetze; A. Binder	[View] [Download]
Abstract: One type of bearing currents that occur at inverter-operation is the high frequency circulating bearing current. This current is induced by the high frequency stator ground current of the motor. Such stator ground currents have been investigated within a research program for systematic investigation of the influence of different system parameters on inverter-induced bearing currents on power levels 11 kW to 500 kW. This paper discusses the influence of motor size, motor-inverter-combination, motor cable type and length and passive filters on the high frequency stator ground currents.

	Comparison of natural sampling and random PWM control strategy for reducing acoustic noise By V. Lanfranchi; A. Hubert; G. Friedrich	[View] [Download]
Abstract: This paper compares the vibratory responses of a well-known mechanical free response stator with two PWM strategies (natural sampling and random) implemented on a TMS320F240 DSP. The presented results are discussed as well as on vibratory response and computing DSP time, for similar THD current, for the two PWM controls in load and no load conditions.

	Performance comparison of different output filter topologies for adjustable speed drives By N. Hanigovszki; J. Poulsen; F. Blaabjerg	[View] [Download]
Abstract: This paper presents a comparison between four different output filter topologies for PWM adjustable speed drives (ASD): choke filter, LC filter, input/output LC filter and filter with return of common mode components to the DC link. The filters are placed between the inverter and the motor cable. Both electromagnetic compatibility (EMC) aspects and machine stress due to high dv/dt values are evaluated. A novel method is used for evaluating output common-mode noise. The paper concludes that there is a trade-off between output filter performance and complexity, as all filters reduce electromagnetic interference (EMI), but only some topologies significantly reduce motor stress.

	Reduction of interference currents in DC traction inverter drives using the highly dynamic torque control By K. Würflinger; C. Foerth; A. Steimel	[View] [Download]
Abstract: In order to eliminate interference currents up to 120 Hz from the dc-line current of traction drives, the existing highly dynamic torque control (Siemens Traction Control - SITRAC [1]) is used. No extra hardware is needed and the control system structure keeps clearly arranged.

	Modelling EMI in PWM inverter-fed AC motor drive systems By C. Vermaelen; F. Costa	[View] [Download]
Abstract: The broad utilisation of PWM inverter-fed variable speed drive in the industrial sector has quickly shown radiated and conducted electromagnetic interference (EMI) problems linked to that kind of supply. In an introduction the different sources and specific couplings of these systems will be presented, then the experimental bench, which allowed us to study the various propagation ways and to measure the various impedances of the AC motor will be described. Thus, this paper explains the working out of a model of these systems. In addition, the identification methods used to achieve the models of the different parts of the system will be examined. Furthermore SPICE models are proposed. Finally the experimental validation of models is discussed.

	Active Power-Factor-Correction has remarkable technical advantages By B. Fuld	[View] [Download]
Abstract: The use of active PFC-circuits should not only be discussed under the aspect of fulfilling normative requirements; it also could help to increase the power of electrical machines in the fieldweakeningrange and to solve the problem of high harmonic currents in the neutral-line, when using a lot of units with single-phase rectifiers. The cost for power-supply installations can be reduced due to the improved power factor. The increased utilization of electrical machines can be reached with active power factor correction circuits based on the boost principle; some known solutions either for single phase and for three phase connection are presented and their specific advantages discussed. Future improvements could be the realised with SiC-diodes and synchronous rectifying.

	Quantification of homopolar components in machines connected to Branch-Delta type soft-starters By D. W. J. Pulle; A. Veltman	[View] [Download]
Abstract: This paper considers the homopolar components which occur in induction machine/branch-delta softstarters combinations.An extension to an ‘ideal rotating transformer’ based transient machine model is introduced to accommodate homopolar components.Results given conﬁrm the presence of a substantial homopolar ﬂux component in the machine.

	Torque ripple in DTC PMSM drives due to nonlinearity of current sensors By L. Laurila; J. Pyrhönen; M. Niemelä	[View] [Download]
Abstract: Nonlinear current measurement errors producing torque ripple in direct torque controlled (DTC) permanent magnet synchronous motor (PMSM) drives are analysed. In this paper the focus is on the nonlinearity of Hall-effect current sensors and its effect on torque ripple. It is demonstrated that nonlinear current measurement errors produce harmonics in the torque.

	Comparative experimental analysis of the effects produced by PWM voltage and current source inverter on a low power induction motor By P. Cancelliere; V. Delli Colli; F. Marignetti; R. Di Stefano	[View] [Download]
Abstract: The paper analyses the performances of a current source inverter with voltage-controlled current modulation, feeding a three-phase induction motor. The discussed current source inverter is fed by a diode rectifier through a current controlled step-down converter. The investigation is conducted by means of an experimental comparison between the proposed inverter and the well-known voltage source inverter drive. Three aspects have been pointed out: harmonic losses, insulation stress, common mode phenomena. The power lost in the induction motor as well as in both inverters has been measured in several steady-state operating conditions. The voltage stress generated by the switching on the motor windings has been recorded for both system under consideration. Finally, the common mode voltage applied to the motor, as well as the circulating common current have been assessed; moreover, the shaft voltage produced by the switching converter operation has been analysed. Aim of the paper is the evaluation of the potential benefits achievable by a current source inverter with a small power induction motor.

	Rotor cage losses of an inverter-fed PMSM investigated with FEM By P. Thelin; H.-P. Nee; J. Soulard; C. Sadarangani; J. Timmerman	[View] [Download]
Abstract: In the design of a compact inverter-fed buried permanent magnet synchronous motor, the high-frequency losses of the sparse rotor cage - which are difficult to predict - were assumed to be small. To investigate these ohmic high-frequency losses of the rotor cage, fixed-speed time-stepping 2DFEM calculations have been carried out. The losses due to only the magnets, magnets and sinusoidal currents, high-frequency currents etc., and the actual currents are presented. The actual current wave-forms were obtained from measurements on the manufactured prototype motor.

	A new model to analyze the impact of inverter supply voltage and cable length on adjustable speed drive motors By S. Amarir; K. AL-Haddad; V. Rajagopalan	[View] [Download]
Abstract: The authors present a new model to evaluate the over-voltages caused partially by the length of the cables feeding motors driven by PWM-controlled inverters. Using the mobile waves theory, a full mathematical formula describing the evolution of the transient voltage at the motor terminals was developed. It takes into account all the parameters on which over-voltages depend in the ASD-motor systems, particularly the cable length, as well as the inverter output voltage rise and fall times. The proposed model, based on this mathematical formula, allows the coordination between the ASD-Motor systems and the length of their feeding cables. The model is validated by simulation, using Matlab/Simulink software, and by experimental results.

	Polynomial and neural methods for characterization and diagnostic of a converter fed synchronous machine By O. Curea; B. Dakyo; G. Barakat	[View] [Download]
Abstract: For the fault detection and the diagnosis, it is useful to have a behavior model of the actual system. A converter fed permanent magnet synchronous machine is used for experimental purpose. The acquisition system is based on the two wattmeter principle, so two voltages and two currents are measured on the three phase side. The representations of the behavior will be chosen simple and relevant for a diagnosis procedure. A polynomial and a neural network approximation for characterization will be presented and compared. For the instant these models work on a personal computer, but is foreseeable a real-time implementation.

	Multi-inverter PWM control: a new generation drive for cruise ship electric propulsion By S. Siala; E. Guette; J. L. Pouliquen	[View] [Download]
Abstract: This paper presents a new generation of ship electric propulsion based on a double star synchronous machine supplied by two P.W.M. I.G.B.T. inverters. The proposed modeling and control allows separating the dynamic modes of the system and keeps the two basic control functions apart: torque control and current balancing. This new electric propulsion has been validated on a two-poded cruise ship with 20MW propulsion power.

	Cable modelling for electrical drives By E. Gubía; P. Sanchis; Ó. Alonso; J. López; A. Lumbreras; L. Marroyo	[View] [Download]
Abstract: Technological improvements in power semiconductors have made possible an important increase both in the switching frequency and in the rated power of the adjustable speed drives (ASD) used in electrical drives. As a drawback, ASD generate pulsed-output voltages with a high rate of voltage rise (dv/dt) that can be greater than 5000V/µs. These dv/dt can cause problems in other elements of the system: premature aging of the machine insulation, bearings deterioration, and EMI. Besides, dv/dt and the output voltage amplitude at motor terminals can increase as a consequence of the stray elements of the cable. In order to deal with these adverse effects, new models are needed that incorporate the high-frequency behaviour of cable elements. In this paper, a generic model for the power cable is proposed to study the low- and high-frequency behaviour of currents and voltages in three-phase drives. With this model, the cables that are used at present can be analysed. In addition, an experimental technique is proposed to calculate model parameters that is based on the operation mode of the electrical drive. The model has been validated for the three most common types of cables: unshielded, with external shield or armour, and shielded conductors.

	A few models of iron loss in the AC machines and transformers due to the harmonics By R. Muszynski	[View] [Download]
Abstract: In the paper a few models for calculation of iron loss in the AC machines and transformers at nonsinusoidal feeding are presented. The differences between the models relate to their form (analytical, simulation), mode of feeding (voltage, current) and to the assumed simplifications, which have effect for the accuracy and frequency range of application. The simplest model has the form of analytical formula, the most compound one reproduces the saturation, hysteresis and eddy current phenomena. In the paper there is description of the separate models and comparison of high harmonic losses obtained with the aid of them for feeding from the voltage as well as current source inverter. There are also given conclusions related to the range of application of the separate models.