EPE Association: EPE 1991 - 42 - Session 4.9: AC DRIVES

EPE 1991 - 42 - Session 4.9: AC DRIVES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 42 - Session 4.9: AC DRIVES

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   MICROCOMPUTER SYSTEM CONTROL IN FIELD COORDINATES OF SYNCHRONOUS MACHINE
By P. Brandstetter; T. Cermak; P. Chlebis; J. Kozina; M. Stefanik [View]
[Download]

Abstract: Microprocessor control in A.C. drives control structures enables to simplificate the circuit solution and thus to increase the reliability of control electronics.The aim is to create an universal hardware system and to adapt the software to control demands. But totally digital control of A.C. drives demands the high calculating performance. The paper refers to the microprocessor control system applicated to A.C. controlled synchronous drive with the cycloconverter supply. The system is based on the INTEL 80186 microprocessor and represents an important new element for the applications to roller tracks and mining machines.

   CHARACTERIZATION AND COMPARISON OF ELECTRICAL DRIVES FOR INDUSTRIAL AUTOMATION
By E. Bassi; F. Benzi [View]
[Download]

Abstract: The paper deals with the evaluation of dynamic performances of electrical drives employed in industrial automation, mainly for positioning purposes of both machine tools and robotic arms. A few drives have been tested in laboratory, particularly for the performances concerning speed and position control loops. The paper reports the frequency analysis for a d.c. permanent magnet and brushless a.c. servodrives; it shows also the behavior of a direct drive motor, by demonstrating the strong dependance of its frequency response from the load inertia, by discussing the requirements for an adaptation procedure. An adaptive algorithm for position control is also presented with simulation results.

   COMMUTATION ANALYSIS OF SYNCHRONOUS MACHINE DRIVES
By W. Deleroi; M. W. Winterling [View]
[Download]

Abstract: To optimize load commutated converter drives synchronous machine dimensions are of fundamental importance. In particular damper winding parameters determine system behaviour. Using accurate models presented in previous papers commutation of synchronous machines with symmetrically wound cylindrical rotor and cylindrical rotor with exclusive d-axis winding is examined. The distribution of currents in the damper winding shows how constant magnetizing current is maintained which ensures safe commutation. The absence of a winding in the rotor q-axis means magnetizing current variations which cause considerably longer commutation time. Passive load variation influences DC voltage while at small firing angles the overlap angle may exceed cycle time. Fast processing and accuracy make the used software a powerful tool for drive design and analysis.

   ECONOMICAL INVERTER-FED AC DRIVES WITH FULLY DIGITAL CONTROL BY MEANS OF AN 8 BIT MICROCONTROLLER
By B. Orlik [View]
[Download]

Abstract: The large majority of the inverter-fed AC drives used in industrial plants are variable speed induction motor drives with open-loop control. Therefore, the precondition for further increasing the number of applications and thus the importance of these drives is to further improve their technical performance, making them at the same time more economical. This can be achieved by fu]ly digitized signal processing by means of microcontrollers. However, the calculation performance, the integrated peripherals and the external memories must be used in an optimum way, i. e. that the implemented control and the modulation must be adapted to the specific characteristics of the microcontroller. Thus, a major step towards favourably priced frequency inverters for AC drives is made.

   AN ALL DIGITAL CONTROL FOR THE LCI FEEDING A SYNCHRONOUS MACHINE
By Rolf Maikath; Ulrich Putz; Reinhard Saupe [View]
[Download]

Abstract: The paper deals with a full digital control for a converter fed synchronous machine. The control is suited for either six or twelve pulse line converter and either six or twelve pulse machine converter. Since the memory of the used processor is limited to 54 kbyte and the clock frequency to 12 MHz special care had to be taken in both hardware architecture and software programming. The paper will show the structure of the control system, some applications and comment on performance results of drives in industrial use.

   CONTROL MODES FOR A VARIABLE-SPEED DRIVE WITH A CONVERTERFED SYNCHRONOUS MACHINE
By G. Frankl [View]
[Download]

Abstract: At first a drive system with a special converterfed synchronous machine is described briefly. lts operational performance is similar to that of a dc machine without auxiliary poles. Different control modes for a variable-speed drive with a converterfed synchronous machine or a commutatorless dc machine are compared in this paper. It gives a survey on the results of a great number of measurements. The subjects of this study are the control of armature current and the speed control above the base speed. Three different control modes are investigated: field control at constant firing angle, control of firing angle at constant field and extinction-angle control. Losses, stability and dynamic performance of these three control methods are compared and the reasons for differences are discussed. The results of a great number of measurements are shown in a few significant figures.

   MOSFET PWM INVERTER FOR LOW VOLTAGE VARIABLE SPEED APPLICATIONS
By Stephan Astier; Jérôme Cros; Michel Lajoie-Mazerc [View]
[Download]

Abstract: This paper deals with a low voltage, 400 W 20 kHz PWM MOSFETs inverter usable to feed variable speed drives in large distribution applications. The example of a motorfan for automotive has been chosen. Severe pressures of the application on cost and using conditions lead to main choices on machine and inverter structures with the aim of minimizing the number of electronic components and sensors for a later integration of electronics in the actuator. After a description of the variable speed actuator feeding structure and of inverter realization, emphasis is put on losses measures of high importance in such a low voltage application. A calorimetric method is used, which allows to separate conduction and switching losses. The main importance of conduction losses is outlined.

   ENVIRONMENTAL IMPACT OF ASD APPLICATIONS IN INDUSTRY
By James A. Oliver; Marek J. Samotyj [View]
[Download]

Abstract: Industry uses 37 percent of the electricity that is produced in the United States. Seventy percent of this drives electric motors. Adjustable speed drives (ASDs) have a major role in solving the environmental problem. ASDs are one of the most effective technologies available for conserving energy. While they conserve energy they are also widely used for improving process control. This benefit is offsetting some of the incremental environmental costs that are being applied to industrial production. In most of the approaches that are being developed to tackle the environmental problem there is a heavy emphasis on energy conservation because energy conservation related directly to reduced fossil power production which cuts Co2, No2 and So2 emissions. In this report, the use of ASDs for energy conservation, increased capacity and reduced emissions in fossil power plants is discussed based on work that has been done. Noise pollution reduction by speed control of fans by ASDs is discussed. ASDs have been used for reduced fish kill in rivers. As an example of what can be accomplished in industry to improve energy efficiency and for the resulting environmental improvement, a number of uses for ASDs in electric utility power plants, in mining, and petroleum refining are discussed. The Los Angeles Basin's plans for electrification of industry to control atmospheric emissions are included to show an example of a possible trend for the rest of the country.

   SIMULATlON OF CONTROLLED CONVERTER-FED SYNCHRONOUS MOTORS
By L. Bojtor; I. Schmidt [View]
[Download]

Abstract: The transient performance of controlled converter fed synchronous motor drives have been investigated using digital simulation based on an accurate system model, state space formulation and per unit system. The paper presents the accurate system model which involves all of the significant energy storage and the nonlinear elements. Both analog and digital controller models are introduced for the simulation. The numerical calculation of the state space equations derived from the accurate system model is discussed in detail. Sample calculation for the starting process of a controlled converter fed synchronous motor drive is presented and compared with experimental results.

   AUTOMATIC CODE GENERATION & ARCHITECTURE CONFIGURATION FOR A HIGH PERFORMANCE TRANSPUTER-BASED UNIVERSAL CONTROLLER
By R. G. Harley; M. J. Van Der Westhuizen; M. R. Webster; D. C. Levy [View]
[Download]

Abstract: High software costs and low software reliability are often used as an argument against the use of digital controllers for motion control. This paper shows that there is a possibility of automating the code generation process for a high performance digital controller based on the transputer. Due to the increasing sophistication of real-time software, software engineers have started to use CASE tools (Computer Assisted Software Engineering) to alleviate this problem. These tools are not widely available yet and therefore a need was identified for a system that can translate a high level specification, typically a control block diagram edited on a graphical, icon-based interface, to executable code which is suitable for multiprocessor execution. The system comprises three main parts; a graphical icon-based editor, a Serial/Parallel Load Analysis Tool (SPLAT) and a code generator that uses the output of SPLAT to generale the executable code. The SPLAT is used to parallelise the algorithm and to determine an optimised architecture configuration for the multiprocessor controller.

   MINIMIZATION OF REACTIVE POWER IN ADJUSTABLE SPEED SLIP POWER RECOVERY DRIVES
By M. G. loannides; J. A. Tegopoulos [View]
[Download]

Abstract: In this paper a generalized model for the optimal control of the adjustable speed slip power recovery system driving a constant load torque at varying speed is deduced. The reactive power exchanged between the machine and the two power sources is minimized subjected to the constraints that the induction machine is driven at any speed under constant load torque and the rotor current is lower than its rated value. The optimal solution of this problem is the rotor voltage space phasor defined from its rms value and its phase angle with respect to the rotor current for each operating point. The characteristics of the drive with minimal reactive power control are studied. The use of this technique leads to the improvement of the overall drive performance.

EPE 1991 - 42 - Session 4.9: AC DRIVES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 42 - Session 4.9: AC DRIVES
	[return to parent folder]

	MICROCOMPUTER SYSTEM CONTROL IN FIELD COORDINATES OF SYNCHRONOUS MACHINE By P. Brandstetter; T. Cermak; P. Chlebis; J. Kozina; M. Stefanik	[View] [Download]
Abstract: Microprocessor control in A.C. drives control structures enables to simplificate the circuit solution and thus to increase the reliability of control electronics.The aim is to create an universal hardware system and to adapt the software to control demands. But totally digital control of A.C. drives demands the high calculating performance. The paper refers to the microprocessor control system applicated to A.C. controlled synchronous drive with the cycloconverter supply. The system is based on the INTEL 80186 microprocessor and represents an important new element for the applications to roller tracks and mining machines.

	CHARACTERIZATION AND COMPARISON OF ELECTRICAL DRIVES FOR INDUSTRIAL AUTOMATION By E. Bassi; F. Benzi	[View] [Download]
Abstract: The paper deals with the evaluation of dynamic performances of electrical drives employed in industrial automation, mainly for positioning purposes of both machine tools and robotic arms. A few drives have been tested in laboratory, particularly for the performances concerning speed and position control loops. The paper reports the frequency analysis for a d.c. permanent magnet and brushless a.c. servodrives; it shows also the behavior of a direct drive motor, by demonstrating the strong dependance of its frequency response from the load inertia, by discussing the requirements for an adaptation procedure. An adaptive algorithm for position control is also presented with simulation results.

	COMMUTATION ANALYSIS OF SYNCHRONOUS MACHINE DRIVES By W. Deleroi; M. W. Winterling	[View] [Download]
Abstract: To optimize load commutated converter drives synchronous machine dimensions are of fundamental importance. In particular damper winding parameters determine system behaviour. Using accurate models presented in previous papers commutation of synchronous machines with symmetrically wound cylindrical rotor and cylindrical rotor with exclusive d-axis winding is examined. The distribution of currents in the damper winding shows how constant magnetizing current is maintained which ensures safe commutation. The absence of a winding in the rotor q-axis means magnetizing current variations which cause considerably longer commutation time. Passive load variation influences DC voltage while at small firing angles the overlap angle may exceed cycle time. Fast processing and accuracy make the used software a powerful tool for drive design and analysis.

	ECONOMICAL INVERTER-FED AC DRIVES WITH FULLY DIGITAL CONTROL BY MEANS OF AN 8 BIT MICROCONTROLLER By B. Orlik	[View] [Download]
Abstract: The large majority of the inverter-fed AC drives used in industrial plants are variable speed induction motor drives with open-loop control. Therefore, the precondition for further increasing the number of applications and thus the importance of these drives is to further improve their technical performance, making them at the same time more economical. This can be achieved by fu]ly digitized signal processing by means of microcontrollers. However, the calculation performance, the integrated peripherals and the external memories must be used in an optimum way, i. e. that the implemented control and the modulation must be adapted to the specific characteristics of the microcontroller. Thus, a major step towards favourably priced frequency inverters for AC drives is made.

	AN ALL DIGITAL CONTROL FOR THE LCI FEEDING A SYNCHRONOUS MACHINE By Rolf Maikath; Ulrich Putz; Reinhard Saupe	[View] [Download]
Abstract: The paper deals with a full digital control for a converter fed synchronous machine. The control is suited for either six or twelve pulse line converter and either six or twelve pulse machine converter. Since the memory of the used processor is limited to 54 kbyte and the clock frequency to 12 MHz special care had to be taken in both hardware architecture and software programming. The paper will show the structure of the control system, some applications and comment on performance results of drives in industrial use.

	CONTROL MODES FOR A VARIABLE-SPEED DRIVE WITH A CONVERTERFED SYNCHRONOUS MACHINE By G. Frankl	[View] [Download]
Abstract: At first a drive system with a special converterfed synchronous machine is described briefly. lts operational performance is similar to that of a dc machine without auxiliary poles. Different control modes for a variable-speed drive with a converterfed synchronous machine or a commutatorless dc machine are compared in this paper. It gives a survey on the results of a great number of measurements. The subjects of this study are the control of armature current and the speed control above the base speed. Three different control modes are investigated: field control at constant firing angle, control of firing angle at constant field and extinction-angle control. Losses, stability and dynamic performance of these three control methods are compared and the reasons for differences are discussed. The results of a great number of measurements are shown in a few significant figures.

	MOSFET PWM INVERTER FOR LOW VOLTAGE VARIABLE SPEED APPLICATIONS By Stephan Astier; Jérôme Cros; Michel Lajoie-Mazerc	[View] [Download]
Abstract: This paper deals with a low voltage, 400 W 20 kHz PWM MOSFETs inverter usable to feed variable speed drives in large distribution applications. The example of a motorfan for automotive has been chosen. Severe pressures of the application on cost and using conditions lead to main choices on machine and inverter structures with the aim of minimizing the number of electronic components and sensors for a later integration of electronics in the actuator. After a description of the variable speed actuator feeding structure and of inverter realization, emphasis is put on losses measures of high importance in such a low voltage application. A calorimetric method is used, which allows to separate conduction and switching losses. The main importance of conduction losses is outlined.

	ENVIRONMENTAL IMPACT OF ASD APPLICATIONS IN INDUSTRY By James A. Oliver; Marek J. Samotyj	[View] [Download]
Abstract: Industry uses 37 percent of the electricity that is produced in the United States. Seventy percent of this drives electric motors. Adjustable speed drives (ASDs) have a major role in solving the environmental problem. ASDs are one of the most effective technologies available for conserving energy. While they conserve energy they are also widely used for improving process control. This benefit is offsetting some of the incremental environmental costs that are being applied to industrial production. In most of the approaches that are being developed to tackle the environmental problem there is a heavy emphasis on energy conservation because energy conservation related directly to reduced fossil power production which cuts Co2, No2 and So2 emissions. In this report, the use of ASDs for energy conservation, increased capacity and reduced emissions in fossil power plants is discussed based on work that has been done. Noise pollution reduction by speed control of fans by ASDs is discussed. ASDs have been used for reduced fish kill in rivers. As an example of what can be accomplished in industry to improve energy efficiency and for the resulting environmental improvement, a number of uses for ASDs in electric utility power plants, in mining, and petroleum refining are discussed. The Los Angeles Basin's plans for electrification of industry to control atmospheric emissions are included to show an example of a possible trend for the rest of the country.

	SIMULATlON OF CONTROLLED CONVERTER-FED SYNCHRONOUS MOTORS By L. Bojtor; I. Schmidt	[View] [Download]
Abstract: The transient performance of controlled converter fed synchronous motor drives have been investigated using digital simulation based on an accurate system model, state space formulation and per unit system. The paper presents the accurate system model which involves all of the significant energy storage and the nonlinear elements. Both analog and digital controller models are introduced for the simulation. The numerical calculation of the state space equations derived from the accurate system model is discussed in detail. Sample calculation for the starting process of a controlled converter fed synchronous motor drive is presented and compared with experimental results.

	AUTOMATIC CODE GENERATION & ARCHITECTURE CONFIGURATION FOR A HIGH PERFORMANCE TRANSPUTER-BASED UNIVERSAL CONTROLLER By R. G. Harley; M. J. Van Der Westhuizen; M. R. Webster; D. C. Levy	[View] [Download]
Abstract: High software costs and low software reliability are often used as an argument against the use of digital controllers for motion control. This paper shows that there is a possibility of automating the code generation process for a high performance digital controller based on the transputer. Due to the increasing sophistication of real-time software, software engineers have started to use CASE tools (Computer Assisted Software Engineering) to alleviate this problem. These tools are not widely available yet and therefore a need was identified for a system that can translate a high level specification, typically a control block diagram edited on a graphical, icon-based interface, to executable code which is suitable for multiprocessor execution. The system comprises three main parts; a graphical icon-based editor, a Serial/Parallel Load Analysis Tool (SPLAT) and a code generator that uses the output of SPLAT to generale the executable code. The SPLAT is used to parallelise the algorithm and to determine an optimised architecture configuration for the multiprocessor controller.

	MINIMIZATION OF REACTIVE POWER IN ADJUSTABLE SPEED SLIP POWER RECOVERY DRIVES By M. G. loannides; J. A. Tegopoulos	[View] [Download]
Abstract: In this paper a generalized model for the optimal control of the adjustable speed slip power recovery system driving a constant load torque at varying speed is deduced. The reactive power exchanged between the machine and the two power sources is minimized subjected to the constraints that the induction machine is driven at any speed under constant load torque and the rotor current is lower than its rated value. The optimal solution of this problem is the rotor voltage space phasor defined from its rms value and its phase angle with respect to the rotor current for each operating point. The characteristics of the drive with minimal reactive power control are studied. The use of this technique leads to the improvement of the overall drive performance.