EPE Association: EPE 1997 – 70: Dialogue Session DS5l: CONTROL OF AC MACHINES: CONTROL AND IMPLEMENTATION

EPE 1997 – 70: Dialogue Session DS5l: CONTROL OF AC MACHINES: CONTROL AND IMPLEMENTATION
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 70: Dialogue Session DS5l: CONTROL OF AC MACHINES: CONTROL AND IMPLEMENTATION

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   AN INTEGRATED DIGITAL SIGNAL PROCESSOR BASED SYSTEM FOR INDUCTION MOTOR VECTOR CONTROL USING OFF LINE PARAMETER IDENTIFICATION
By M. N. Marwali; A. Keyhani; W. Tjanaka [View]
[Download]

Abstract: This paper presents an implementation of indirect vector control of induction machine on an integrated Digital Signal Processor (DSP) system manufactured by dSPACE GmbH. The system integrates into a single board the computational power of a TMS320C31 DSP with extra periphyrals needed in vector control application, and therefore requires minimal hard¥are development. The induction machine parameters required for the vector control operation are obtained through an off line parameters identification using Maximum Likelihood estimation technique with a DC voltage source excitation. It is shown through extensive experimental study that the off line identified parameters yield in a reliable field orientation of the induction machine.

   PSEUDO TORQUE CONTROL (PTC) - A NEW CONTROL CONCEPT FOR INDUCTION MOTORS
By C. Tuttas [View]
[Download]

Abstract: The Pseudo Torque Control (PTC) concept for induction motors is based on indirect field orientation. Instead of the stator currents artificial control variables (pseudo torques) are impressed into the motor by hysteresis controller. So, a field oriented direct torque control becomes approximately possible. The PTC concept is insensitive to variations of the rotor time constant of induction motors.

   System Performance of Fieldbus Linked Electric Drives
By M. Franke; G.-H. Geitner [View]
[Download]

Abstract: The systematic investigation of the performance of fieldbus linked electric drive systems is a very important basis for practical applications. The paper presents a method to calculate the system behaviour in case of an emergency stop by use of general system parameters. An analytical method will be presented for simple configurations. Aspects of asynchronous data transfer will be discussed. The sample times are mostly non-constant if control loops are closed via a serial bus system. The second part of this paper shows an optimisation method for digital controllers with non-constant sample times for data measurement. Simulation results will be presented. The results are useful as a decision tool for the choice and the configuration of fieldbus linked drive systems.

   IMPROVEMENT OF THE OPERATION LIMIT OF A FIELD-WEAKENING SPEED CONTROL SYSTEM FOR A SELF-CONTROLLED SYNCHRONOUS MOTOR
By S. Nishikata; T. Namba [View]
[Download]

Abstract: A simple method to enlarge the operation limit of a field-weakening speed control system for a self-controlled synchronous motor is proposed. It is shown that in the case of a constant set value for the de input current limiter the angle of overlap of armature currents increases greatly when speed reference is increased, and maximum allowable change in speed reference is restricted to a relatively small value. A variable current limiter, in which the set value for the de input current limiter is changed in such a way that it is proportional to the field current of the motor, is useful for limiting an excessive increase in the angle of overlap in transients, and it is shown that the change in speed reference without commutation failure can be widened greatly with this limiter, The effects of magnetic saturation on the steady-state speed region in which commutation failure does not occur during transients are also clarified.

   CONVERTER CONTROL OF ASYNCHRONOUS MOTOR DRIVE WITH MINIMUM CURRENT CONSUMPTION
By Zdenek Cerovsky; Jiri Javurek [View]
[Download]

Abstract: Vector control of the electrical drive enables independent control of the magnetic flux and torque of asynchronous motors. The current supplied to the motor from the converter is determined by magnetic flux and desired torque. Optimally assigned magnetic flux enables to generate the desired torque with.a minimum converter current. The paper describes the theory, the method of calculation, and the implementation of real converter control for a traction drive. Both the vector control and the direct torque control are taken into consideration.

   FILTERED PWM-INVERTER OUTPUT WAVEFORMS IN A MEDIUM SPEED (<30000 rpm) SOLID-ROTOR INDUCTION MOTOR DRIVE
By Jussi Huppunen; Juha Pyrhönen [View]
[Download]

Abstract: Inverter output harmonics create great amount of losses in solid rotor induction motors. An output filter for a PWM-inverter is introduced to smoothen the inverter output waveforms. The efficiency of the solid rotor induction motor will increase remarkably. The filter is designed so that it also compensates the no-load magnetising current of the motor. Thus a clearly smaller inverter can be chosen especially in high power applications.

   DYNAMIC MODELING AND MODEL BASED CONTROL OF AN INDUCTION MACHINE
By L. Krüger; D. Naunin [View]
[Download]

Abstract: The proposed approach - without using of analytical system knowledge - seems to be a useful instrument to model and control nonlinear dynamic systems. Therefore a representations of non-linear discrete time systems and two model-based control structures [Internal Model Control (IMC) and Model Predictive Control (MPC)] of an induction motor. are discussed. To acquire the system data for estimation the drive was stimulated by a random ternary speed reference signal sequence. Different nonlinear model structures- the stochastic NARMAX-model- and different kinds of artificial Neural Networks - the Multilayer Perceptron Network (MLP) and the Radial Basis· Function Network (RBF) - have been used to model the real process dynamics. These structures are compared with regard to the modeling validity and the computational expense on a parallel processor system. Furthermore the control performance of both control structures are discussed.

   FEEDBACK LINEARISATION AND MULTIVARIABLE CASCADED PREDICTIVE STRUCTURE CONTROL OF INDUCTION MACHINE
By P. Boucher; A. Benyahia; D. Dumur [View]
[Download]

Abstract: A nonlinear speed control of an induction machine based on the internal model is presented in this paper. The control law is a multivariable cascaded generalized predictive control with multiple reference model algorithm (MCGPC/MRM), based on the input-output torque and flux linearised machine model in the stator fixed reference frame. A complete control law with a flux observer and a current limitation is also presented.

   R-S-T REGULATORS FOR AN INDUCTION MOTOR DRIVE : COMPARATIVE STUDY
By I. Slama-Belkhodja; Bernard de Fomel [View]
[Download]

Abstract: This paper shows that, for an induction motor drive, performances and robustness change a lot with the R-S-T regulator design and they can be improved by specifying separate desired closed loop performances for regulation and tracking. The adopted strategy design permits to evade induction motor drive nonlinearities and coupling problems.

   ANTI-WINDUP OF CURRENT REGULATORS CONSIDERING INVERTER SATURATION
By Dong-Choon Lee; G-Myoung Lee [View]
[Download]

Abstract: In high performance drives of induction motors, the current controller usually undergoes a windup because of voltage limitation due to an inverter saturation. In this paper, to remove the windup, a novel anti-windup technique which makes use of the output voltage of the space vector PWM inverter to the maximum is proposed. For the speed PI controller in addition, the windup problem is solved. The validity of the proposed technique is confirmed by simulation results for 10 Hp induction motor drives.

   THE NEW CSI CONTROL STRATEGY FOR AVOIDING SLOW RESPONSE IN VECTOR CONTROLLED INDUCTION MOTOR DRIVE
By A. B. Nikolic; B. I. Jeftenic [View]
[Download]

Abstract: In this paper the new control strategy for vector controlled CSI fed induction motor drive is proposed. The goal of this work is to create adequate inverter control circuitery for avoiding problems with slow torque response and flux disturbance. The analyzed problems with vector control of CSI are mostly in the transient period, when the torque command is changed. As a result there is an instantaneous loss of field orientation which produces a very sluggish torque response. The analysis of proposed control strategy has been done on the mathematical model realized and tested in MATLAB SIMULINK for Windows software.

   PERIODIC RESPONSES OF A NONLINEAR CURRENT CONTROLLED IM DRIVE
By Zoltan Sütö; Istvan Nagy; Jako Zoltan [View]
[Download]

Abstract: The main objective of the paper is to highlight the strange behaviour of a class of power electronic system through an example of an induction motor fed by a voltage source inverter and controlled by tolerance band current controller. The paper presents simulation results for periodic and chaotic states of the system, and studies astonishing properties of transitions between them. Changing some system parameters, various regularities can be discovered. Period doubling, bend splitting and window periodicity will be presented. Averaged Lyapunov exponent has been calculated. The final aim of this research is to find ways of locking and stabilizing the system trajectories along periodic orbits.

   CONTROL SYSTEM FOR THE VOLTAGE SOURCE DC LINK CONVERTER IN THE ROTOR CIRCUIT OF A SLIP RING INDUCTION MACHINE
By Helmut Weiss; Markus Lampersberger [View]
[Download]

Abstract: The rotating system tie frequency converter of the German Railways, Hamburg-Harburg E2 incorporates a double-fed induction motor. Torque control is accomplished by a voltage source PWM-inverter at the rotor circuit. The power transfer operation rotational speed of this machine set is within few percent fluctuation near synchronous speed. For such a system, only the slip power - according to slip only a few percent of actual active power - has to be transferred at the rotor by means of the PWM-inverter. Slip power is transferred from/to the DC-link via a line commutated inverter / rectifier. The same power electronics circuit enables accelation of the machine set from zero to synchronous speed when the stator of the induction motor is short-circuited and the rotor is fed by the PWM-inverter. The control system has to accomplish these quite different modes of operation including synchronization. Line failures cause extreme high machine currents. The control system failure reaction circuit is triggered by these overcurrents, sets the system to a secure state without opening the circuit breakers and regaines standard operation automatically. The original control system for acceleration, regular and transient operation has been tested at a laboratory model before ifs delivery to the plant.

   A NEW CONTROL METHOD OF ACTIVE TORQUE RIPPLES FILTER IN HIGH POWER ELECTRICAL MACHINES
By A. Khezzar; B. Davat [View]
[Download]

Abstract: Presented paper introduces a design of a new scheme control for the active filtering of torque ripples in high power AC machines. This control principle is based only on the instantaneous active power calculation, while the instantaneous reactive power existing in each phase independently, vanishes when added. Therefore, the authors have given in the first a review of pq theory as introduced in the references [1,2,3], and the active filtering of torque ripples principle [4,5,6]. Some simulation results are presented and discussed.

EPE 1997 – 70: Dialogue Session DS5l: CONTROL OF AC MACHINES: CONTROL AND IMPLEMENTATION
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 70: Dialogue Session DS5l: CONTROL OF AC MACHINES: CONTROL AND IMPLEMENTATION
	[return to parent folder]

	AN INTEGRATED DIGITAL SIGNAL PROCESSOR BASED SYSTEM FOR INDUCTION MOTOR VECTOR CONTROL USING OFF LINE PARAMETER IDENTIFICATION By M. N. Marwali; A. Keyhani; W. Tjanaka	[View] [Download]
Abstract: This paper presents an implementation of indirect vector control of induction machine on an integrated Digital Signal Processor (DSP) system manufactured by dSPACE GmbH. The system integrates into a single board the computational power of a TMS320C31 DSP with extra periphyrals needed in vector control application, and therefore requires minimal hard¥are development. The induction machine parameters required for the vector control operation are obtained through an off line parameters identification using Maximum Likelihood estimation technique with a DC voltage source excitation. It is shown through extensive experimental study that the off line identified parameters yield in a reliable field orientation of the induction machine.

	PSEUDO TORQUE CONTROL (PTC) - A NEW CONTROL CONCEPT FOR INDUCTION MOTORS By C. Tuttas	[View] [Download]
Abstract: The Pseudo Torque Control (PTC) concept for induction motors is based on indirect field orientation. Instead of the stator currents artificial control variables (pseudo torques) are impressed into the motor by hysteresis controller. So, a field oriented direct torque control becomes approximately possible. The PTC concept is insensitive to variations of the rotor time constant of induction motors.

	System Performance of Fieldbus Linked Electric Drives By M. Franke; G.-H. Geitner	[View] [Download]
Abstract: The systematic investigation of the performance of fieldbus linked electric drive systems is a very important basis for practical applications. The paper presents a method to calculate the system behaviour in case of an emergency stop by use of general system parameters. An analytical method will be presented for simple configurations. Aspects of asynchronous data transfer will be discussed. The sample times are mostly non-constant if control loops are closed via a serial bus system. The second part of this paper shows an optimisation method for digital controllers with non-constant sample times for data measurement. Simulation results will be presented. The results are useful as a decision tool for the choice and the configuration of fieldbus linked drive systems.

	IMPROVEMENT OF THE OPERATION LIMIT OF A FIELD-WEAKENING SPEED CONTROL SYSTEM FOR A SELF-CONTROLLED SYNCHRONOUS MOTOR By S. Nishikata; T. Namba	[View] [Download]
Abstract: A simple method to enlarge the operation limit of a field-weakening speed control system for a self-controlled synchronous motor is proposed. It is shown that in the case of a constant set value for the de input current limiter the angle of overlap of armature currents increases greatly when speed reference is increased, and maximum allowable change in speed reference is restricted to a relatively small value. A variable current limiter, in which the set value for the de input current limiter is changed in such a way that it is proportional to the field current of the motor, is useful for limiting an excessive increase in the angle of overlap in transients, and it is shown that the change in speed reference without commutation failure can be widened greatly with this limiter, The effects of magnetic saturation on the steady-state speed region in which commutation failure does not occur during transients are also clarified.

	CONVERTER CONTROL OF ASYNCHRONOUS MOTOR DRIVE WITH MINIMUM CURRENT CONSUMPTION By Zdenek Cerovsky; Jiri Javurek	[View] [Download]
Abstract: Vector control of the electrical drive enables independent control of the magnetic flux and torque of asynchronous motors. The current supplied to the motor from the converter is determined by magnetic flux and desired torque. Optimally assigned magnetic flux enables to generate the desired torque with.a minimum converter current. The paper describes the theory, the method of calculation, and the implementation of real converter control for a traction drive. Both the vector control and the direct torque control are taken into consideration.

	FILTERED PWM-INVERTER OUTPUT WAVEFORMS IN A MEDIUM SPEED (<30000 rpm) SOLID-ROTOR INDUCTION MOTOR DRIVE By Jussi Huppunen; Juha Pyrhönen	[View] [Download]
Abstract: Inverter output harmonics create great amount of losses in solid rotor induction motors. An output filter for a PWM-inverter is introduced to smoothen the inverter output waveforms. The efficiency of the solid rotor induction motor will increase remarkably. The filter is designed so that it also compensates the no-load magnetising current of the motor. Thus a clearly smaller inverter can be chosen especially in high power applications.

	DYNAMIC MODELING AND MODEL BASED CONTROL OF AN INDUCTION MACHINE By L. Krüger; D. Naunin	[View] [Download]
Abstract: The proposed approach - without using of analytical system knowledge - seems to be a useful instrument to model and control nonlinear dynamic systems. Therefore a representations of non-linear discrete time systems and two model-based control structures [Internal Model Control (IMC) and Model Predictive Control (MPC)] of an induction motor. are discussed. To acquire the system data for estimation the drive was stimulated by a random ternary speed reference signal sequence. Different nonlinear model structures- the stochastic NARMAX-model- and different kinds of artificial Neural Networks - the Multilayer Perceptron Network (MLP) and the Radial Basis· Function Network (RBF) - have been used to model the real process dynamics. These structures are compared with regard to the modeling validity and the computational expense on a parallel processor system. Furthermore the control performance of both control structures are discussed.

	FEEDBACK LINEARISATION AND MULTIVARIABLE CASCADED PREDICTIVE STRUCTURE CONTROL OF INDUCTION MACHINE By P. Boucher; A. Benyahia; D. Dumur	[View] [Download]
Abstract: A nonlinear speed control of an induction machine based on the internal model is presented in this paper. The control law is a multivariable cascaded generalized predictive control with multiple reference model algorithm (MCGPC/MRM), based on the input-output torque and flux linearised machine model in the stator fixed reference frame. A complete control law with a flux observer and a current limitation is also presented.

	R-S-T REGULATORS FOR AN INDUCTION MOTOR DRIVE : COMPARATIVE STUDY By I. Slama-Belkhodja; Bernard de Fomel	[View] [Download]
Abstract: This paper shows that, for an induction motor drive, performances and robustness change a lot with the R-S-T regulator design and they can be improved by specifying separate desired closed loop performances for regulation and tracking. The adopted strategy design permits to evade induction motor drive nonlinearities and coupling problems.

	ANTI-WINDUP OF CURRENT REGULATORS CONSIDERING INVERTER SATURATION By Dong-Choon Lee; G-Myoung Lee	[View] [Download]
Abstract: In high performance drives of induction motors, the current controller usually undergoes a windup because of voltage limitation due to an inverter saturation. In this paper, to remove the windup, a novel anti-windup technique which makes use of the output voltage of the space vector PWM inverter to the maximum is proposed. For the speed PI controller in addition, the windup problem is solved. The validity of the proposed technique is confirmed by simulation results for 10 Hp induction motor drives.

	THE NEW CSI CONTROL STRATEGY FOR AVOIDING SLOW RESPONSE IN VECTOR CONTROLLED INDUCTION MOTOR DRIVE By A. B. Nikolic; B. I. Jeftenic	[View] [Download]
Abstract: In this paper the new control strategy for vector controlled CSI fed induction motor drive is proposed. The goal of this work is to create adequate inverter control circuitery for avoiding problems with slow torque response and flux disturbance. The analyzed problems with vector control of CSI are mostly in the transient period, when the torque command is changed. As a result there is an instantaneous loss of field orientation which produces a very sluggish torque response. The analysis of proposed control strategy has been done on the mathematical model realized and tested in MATLAB SIMULINK for Windows software.

	PERIODIC RESPONSES OF A NONLINEAR CURRENT CONTROLLED IM DRIVE By Zoltan Sütö; Istvan Nagy; Jako Zoltan	[View] [Download]
Abstract: The main objective of the paper is to highlight the strange behaviour of a class of power electronic system through an example of an induction motor fed by a voltage source inverter and controlled by tolerance band current controller. The paper presents simulation results for periodic and chaotic states of the system, and studies astonishing properties of transitions between them. Changing some system parameters, various regularities can be discovered. Period doubling, bend splitting and window periodicity will be presented. Averaged Lyapunov exponent has been calculated. The final aim of this research is to find ways of locking and stabilizing the system trajectories along periodic orbits.

	CONTROL SYSTEM FOR THE VOLTAGE SOURCE DC LINK CONVERTER IN THE ROTOR CIRCUIT OF A SLIP RING INDUCTION MACHINE By Helmut Weiss; Markus Lampersberger	[View] [Download]
Abstract: The rotating system tie frequency converter of the German Railways, Hamburg-Harburg E2 incorporates a double-fed induction motor. Torque control is accomplished by a voltage source PWM-inverter at the rotor circuit. The power transfer operation rotational speed of this machine set is within few percent fluctuation near synchronous speed. For such a system, only the slip power - according to slip only a few percent of actual active power - has to be transferred at the rotor by means of the PWM-inverter. Slip power is transferred from/to the DC-link via a line commutated inverter / rectifier. The same power electronics circuit enables accelation of the machine set from zero to synchronous speed when the stator of the induction motor is short-circuited and the rotor is fed by the PWM-inverter. The control system has to accomplish these quite different modes of operation including synchronization. Line failures cause extreme high machine currents. The control system failure reaction circuit is triggered by these overcurrents, sets the system to a secure state without opening the circuit breakers and regaines standard operation automatically. The original control system for acceleration, regular and transient operation has been tested at a laboratory model before ifs delivery to the plant.

	A NEW CONTROL METHOD OF ACTIVE TORQUE RIPPLES FILTER IN HIGH POWER ELECTRICAL MACHINES By A. Khezzar; B. Davat	[View] [Download]
Abstract: Presented paper introduces a design of a new scheme control for the active filtering of torque ripples in high power AC machines. This control principle is based only on the instantaneous active power calculation, while the instantaneous reactive power existing in each phase independently, vanishes when added. Therefore, the authors have given in the first a review of pq theory as introduced in the references [1,2,3], and the active filtering of torque ripples principle [4,5,6]. Some simulation results are presented and discussed.