EPE Association: EPE 1989 - 08 - Lecture Session 2.1: SIGNAL PROCESSING

EPE 1989 - 08 - Lecture Session 2.1: SIGNAL PROCESSING
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   RESISTANCE CORRECTED AND TIME DISCRETE CALCULATION OF ROTOR FLUX IN INDUCTION MOTORS
By G. Pfaff; H. Segerer; A. Lelkes [View]
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Abstract: Mostly high dynamic control of induction motor depends on the knowledge of rotor flux. Usually the flux is calculated by machine models or by observers. Their digital realization in processors demands a time discrete equation system approximating the differential equations. A precise flux calculation usually requires a small sampling period, which is given by the processors performance. Respecting the time discrete character of the applied inverter, a longer sampling period is given by the switching frequency of the inverter. Since the sampling period is now longer than usually, also extensive calculations can be made on-line. The design principles and experimental results of a time discrete machine model respecting the time discrete character of a constant d.c. link voltage inverter are shown in this paper. The longer sampling period allows to correct on-line all model coefficients depending on resistances. For this, the stator temperature and the stator currents are measured. All applied equations are based on the dynamic behaviour of the induction motor .

   ROTOR FLUX CALCULATOR FOR SATURATED INDUCTION MACHINES WITH FIELD-ORIENTED CONTROL
By V. Vuckovic; E. Levi [View]
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Abstract: The paper deals with field-oriented controlled current fed induction machines. The discussed scheme comprises rotor flux space vector estimation on the basis of stator currents and rotor speed measurement. The influence of main flux saturation on rotor flux and slip frequency calculation can be significant during operation in field-weakening region and during rapid accelerations of the drive. As a consequence, discrepancies between actual and estlmated values occur and unsaturated model used in the control part of the drive should be substituted with a convenient saturated model. The paper presents such a model, which can be implemented instead of the nonsaturated one and which takes into account effects of main flux saturation. If this model is applied in the control part of the drive, calculated values of rotor flux amplitude and angular position fit very well with actual values and the desired level of rotor flux can be maintained through the flux regular action, irrespective of the level of saturation. The theoretical results are verified by the aid of digital simulation.

   A FAM VOLTAGE CONTROLLER FOR ASYNCHRONOUS MOTOR DRIVES
By A. M. Sharaf; A. Ch. Rufer; L. Brientini [View]
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Abstract: The paper presents the design and prototype implementation of a modified version of slip frequency control based on Field Acceleration Method (FAM) proposed by Yamamura (1, 2). The current-FAM controller was implemented using the BBC Programmable high speed controller and tested on a pulse width modulated voltage source (PWM-VSI) inverter with switchable low carrier frequency to simulate possible use on GTO inverters.

   HIGH DYNAMIC CONTROL OF AC INDUCTION MOTOR DRIVES IMPROVED BY ASICS
By T. Henke; U. Rathert; R. Lessmeier; R. Gabriel [View]
[Download]

Abstract: The design of AC motor controllers either for high dynamic performance or for low cost drives still suffers from the complexity of the circuits. With the creation of specialised integrated circuits for AC motor control part count and cost can be reduced. A gate array for pulse width modulation (PWM) and a cell design for the evaluation of an incremental encoder are presented. Both ICs show higher resolution and speed compared with discrete designs. As shown in the experimental results of an induction motor servo drive the ICs help to reduce the delay in the current control loop and to eliminate the noise of the drive by increasing the switching frequency beyond the audible range.

   A GATE ARRAY DESIGN FOR PWM INVERTER CONTROL
By T. C. Green; B. W. Williams [View]
[Download]

Abstract: In order for induction motor drives to be competitive in the low power drives market an inexpensive control chip set must be developed. This paper presents a design philosophy for producing a single chip solution with a reduced silicon area. This involves reducing the amount of storage required for the reference waveform and simplifying the modulator circuitry. The compromises that are required in order to reach the solution are investigated and from this a design is evolved. The design is implemented using the latest ASIC technology - programmable gate arrays - as a proving stage for gate array production. The performance is assessed in terms of the frequency spectrum of the PWM waveforms and shown to be adequate for low cost, low power applications such as consumer goods.

   SERVOCONIC CHIP-SET: COMPLETE CONTROL CIRCUITRY FOR VECTOR~CONTROLLED INDUCTION MOTOR DRIVES
By Errol S. Tez [View]
[Download]

Abstract: The paper presents a chip-set comprising four VLSI devices, which has been developed specifically for vector-controlled variable-speed induction motor drives using standard 3-phase squirrel-cage motors. The chip-set provides all the control, communication and protection facilities necessary for such drive systems. Following a brief discussion on the vector control methods and inverter topologies, the system architecture of the chip-set is described together with its internal functional blocks. The performance advantages resulting from the new control technique are summarized. Many applications currently using open-loop A.C. drives are expected to benefit from the novel integrated approach offered by the chipset.

EPE 1989 - 08 - Lecture Session 2.1: SIGNAL PROCESSING
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 08 - Lecture Session 2.1: SIGNAL PROCESSING
	[return to parent folder]

	RESISTANCE CORRECTED AND TIME DISCRETE CALCULATION OF ROTOR FLUX IN INDUCTION MOTORS By G. Pfaff; H. Segerer; A. Lelkes	[View] [Download]
Abstract: Mostly high dynamic control of induction motor depends on the knowledge of rotor flux. Usually the flux is calculated by machine models or by observers. Their digital realization in processors demands a time discrete equation system approximating the differential equations. A precise flux calculation usually requires a small sampling period, which is given by the processors performance. Respecting the time discrete character of the applied inverter, a longer sampling period is given by the switching frequency of the inverter. Since the sampling period is now longer than usually, also extensive calculations can be made on-line. The design principles and experimental results of a time discrete machine model respecting the time discrete character of a constant d.c. link voltage inverter are shown in this paper. The longer sampling period allows to correct on-line all model coefficients depending on resistances. For this, the stator temperature and the stator currents are measured. All applied equations are based on the dynamic behaviour of the induction motor .

	ROTOR FLUX CALCULATOR FOR SATURATED INDUCTION MACHINES WITH FIELD-ORIENTED CONTROL By V. Vuckovic; E. Levi	[View] [Download]
Abstract: The paper deals with field-oriented controlled current fed induction machines. The discussed scheme comprises rotor flux space vector estimation on the basis of stator currents and rotor speed measurement. The influence of main flux saturation on rotor flux and slip frequency calculation can be significant during operation in field-weakening region and during rapid accelerations of the drive. As a consequence, discrepancies between actual and estlmated values occur and unsaturated model used in the control part of the drive should be substituted with a convenient saturated model. The paper presents such a model, which can be implemented instead of the nonsaturated one and which takes into account effects of main flux saturation. If this model is applied in the control part of the drive, calculated values of rotor flux amplitude and angular position fit very well with actual values and the desired level of rotor flux can be maintained through the flux regular action, irrespective of the level of saturation. The theoretical results are verified by the aid of digital simulation.

	A FAM VOLTAGE CONTROLLER FOR ASYNCHRONOUS MOTOR DRIVES By A. M. Sharaf; A. Ch. Rufer; L. Brientini	[View] [Download]
Abstract: The paper presents the design and prototype implementation of a modified version of slip frequency control based on Field Acceleration Method (FAM) proposed by Yamamura (1, 2). The current-FAM controller was implemented using the BBC Programmable high speed controller and tested on a pulse width modulated voltage source (PWM-VSI) inverter with switchable low carrier frequency to simulate possible use on GTO inverters.

	HIGH DYNAMIC CONTROL OF AC INDUCTION MOTOR DRIVES IMPROVED BY ASICS By T. Henke; U. Rathert; R. Lessmeier; R. Gabriel	[View] [Download]
Abstract: The design of AC motor controllers either for high dynamic performance or for low cost drives still suffers from the complexity of the circuits. With the creation of specialised integrated circuits for AC motor control part count and cost can be reduced. A gate array for pulse width modulation (PWM) and a cell design for the evaluation of an incremental encoder are presented. Both ICs show higher resolution and speed compared with discrete designs. As shown in the experimental results of an induction motor servo drive the ICs help to reduce the delay in the current control loop and to eliminate the noise of the drive by increasing the switching frequency beyond the audible range.

	A GATE ARRAY DESIGN FOR PWM INVERTER CONTROL By T. C. Green; B. W. Williams	[View] [Download]
Abstract: In order for induction motor drives to be competitive in the low power drives market an inexpensive control chip set must be developed. This paper presents a design philosophy for producing a single chip solution with a reduced silicon area. This involves reducing the amount of storage required for the reference waveform and simplifying the modulator circuitry. The compromises that are required in order to reach the solution are investigated and from this a design is evolved. The design is implemented using the latest ASIC technology - programmable gate arrays - as a proving stage for gate array production. The performance is assessed in terms of the frequency spectrum of the PWM waveforms and shown to be adequate for low cost, low power applications such as consumer goods.

	SERVOCONIC CHIP-SET: COMPLETE CONTROL CIRCUITRY FOR VECTOR~CONTROLLED INDUCTION MOTOR DRIVES By Errol S. Tez	[View] [Download]
Abstract: The paper presents a chip-set comprising four VLSI devices, which has been developed specifically for vector-controlled variable-speed induction motor drives using standard 3-phase squirrel-cage motors. The chip-set provides all the control, communication and protection facilities necessary for such drive systems. Following a brief discussion on the vector control methods and inverter topologies, the system architecture of the chip-set is described together with its internal functional blocks. The performance advantages resulting from the new control technique are summarized. Many applications currently using open-loop A.C. drives are expected to benefit from the novel integrated approach offered by the chipset.