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Industry Applications, IEEE Transactions on

Issue 5 • Date Sep/Oct 1991

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Displaying Results 1 - 25 of 28
  • Design and performance of an acceleration drive with permanent magnets

    Page(s): 908 - 913
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    Aspects of the design of an acceleration drive are discussed. To prevent a decrease of torque at high speeds, special reference waveforms of the phase current are proposed. The motor is fed by an inverter with high pulse frequencies. The drives have the ability to accelerate a given moment of inertia up to a high speed within a short transition time. The length, diameter, and inner construction of the rotor are discussed. Because a hollow cylinder is favorable, motors with permanent magnets are superior to induction motors. A simple method of analyzing the magnetic circuit, including saturation effects, is given. Additional losses caused by the inverter-fed operation in combination with the low-inductive armature winding were reduced to one-seventh of the original amount by modifications in the current control loop. Two examples of current reference waveforms that lead to higher torques in the high-speed region than the conventional block form are given. Experimental verification was obtained from the magnetic, electric, and thermal points of view by testing an experimental drive during more than half a million duty cycles View full abstract»

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  • Mechanism of interaction between electric arc and breaking chamber in low voltage current limiting circuit breakers

    Page(s): 841 - 848
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    The authors survey different types of contact arrangements with simple, double, and quadruple arc interruption in current-limiting low-voltage protective switching devices. The influence of the arc commutation from moving contact arm to commutation bar is discussed. A new type of rapid electromagnet with a rotating armature is presented. The performance of the electromagnet was investigated by the finite element method. The same method was used to study the configuration of the arcing chamber and the influence of different parameters on the contact repulsion forces. The experiments were carried out with the help of a capacitor bank, and the results were measured by a data acquisition system View full abstract»

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  • Latest rotary kiln burner technology: possibilities and experiences

    Page(s): 798 - 806
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    The author describes the development of a rotary kiln burner for pulverized coal. A distinction is made between three generations of burners, with their typical design and process philosophies. Since environmental concerns led to considerable research on the mechanisms of the formation and behavior of nitrogen oxides in rotary kilns, the possibilities burners give for less NOx formation are given special attention. Experience with the latest developments in burners is described, and recommendations are given for further improvements. The author concludes that the latest flame philosophy, producing a slim, slightly longer but concentrated flame without divergence, is the right way to reduce NOx formation and gives the best process results View full abstract»

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  • Control dynamics of speed drive systems using sliding mode controllers with integral compensation

    Page(s): 883 - 892
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    The authors describe the control dynamics and robustness improvement of vector-controlled AC speed drive systems using sliding mode control with integral compensation (SLMC-I). The dynamics of step command speed and impact load disturbance under SLMC-I control are formulated and studied. Acceleration estimation techniques using observers and nonideal differentiators for the SLMC-I speed drive systems are outlined and compared. The control dynamics of SLMC-I with increased system order are discussed. The techniques of robustness improvement for the SLMC-I drives are presented. A method of control in which the sliding line is fed forward is developed to enhance the drive robustness. The control dynamics with this method of control are investigated. The effectiveness of the scheme is demonstrated through computer simulations and experimental work View full abstract»

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  • A wide constant power range vector-controlled AC motor drive using winding changeover technique

    Page(s): 934 - 939
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    A high-performance vector-controlled induction motor drive with a very wide constant power range of 1:10 to 1:30 has been developed and widely accepted in the spindle drives of machine tools. The motor has two combinations of winding connections, and one of them is selected in accordance with the operating conditions. The versatility of the winding changeover technique has been introduced and demonstrated. A wide constant power range is achieved, and the gear box used in a conventional machine is eliminated. In addition, it was proved by actual operations that the machining operation can be continued during the changeover without sacrificing the quality of the final product. The basic idea, features, and test results of this technique are described View full abstract»

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  • Characteristics and applications of various arc interrupting methods

    Page(s): 849 - 861
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    The authors present an analysis of arc interruption media, their strengths and weaknesses, and maintenance requirements. Differences in arc interruption by voltage class are also examined. The authors list some of the key elements and focus on only those elements addressed within the design of the particular device being discussed. These elements include cathode/anode action, extreme thermal agitation, moving positive ions, electrons carried by field, diffusion, recombination, and collision. The discussion on each of these items aids in an understanding of how equipment is designed, applied, and better maintained View full abstract»

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  • PWM-CSI induction motor drive with phase angle control

    Page(s): 970 - 976
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    The authors describe a pulse-width-modulated current-source inverter drive system using an induction motor. Its dominant feature is that it provides adequate control of either torque or speed over a wide range without requiring a shaft position or speed sensor. The capacitor-loaded current-source invertor system has the advantages of simplicity, low switching frequency, four-quadrant operation, overcurrent protection, and low harmonic content in the motor current and voltage. The choice of maximum value for the capacitor depends on the degree of nonlinearity that can be tolerated in the torque-stator current relation, whereas its minimum value depends on the need for a low impedance path for inverter current harmonics. The control strategy is based on the concept of controlling the stator phase angle of the induction motor. The stator voltage is sensed, and the current-source inverter is used to inject current into the motor with the desired phase angle View full abstract»

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  • Control strategies for direct torque control using discrete pulse modulation

    Page(s): 893 - 901
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    A scheme for direct torque control of AC machines using discrete pulse-modulated inverters such as the resonant DC link inverter is presented. A unique feature of the control method is that only one current sensor in the DC link is required. Excellent control of torque, stator flux, and motor current waveshapes is seen to be obtained without affecting the high dynamic performance associated with direct self control (DSC) of machines. By defining a control that does not use the zero voltage vector, an observer is purposed for estimation of the motor current using only one current sensor in the DC link. A direct bang-bang (sliding mode) torque controller is then derived on the basis of this current observer. Experimental verification of simulation results is included on a resonant DC link inverter drive with a switching frequency of 27 kHz. The inverter switching scheme is implemented using a real-time Motorola DSP56000 digital signal processor-based controller View full abstract»

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  • A three-phase PWM strategy using a stepped reference waveform [invertor drives]

    Page(s): 914 - 920
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    The theoretical derivation of a carrier-based three phase pulse-width-modulated (PWM) technique for invertor drives using a stepped reference waveform is presented. The reference waveform is divided into 30° intervals, with each interval being controlled individually to control the magnitude of the fundamental harmonic. This process contrasts with the commonly used approach of amplitude modulating the entire reference waveform to control the fundamental harmonic. The resultant PWM technique is shown to be similar to a square-wave strategy but with a lower current distortion being obtained at high fundamental magnitudes and high carrier frequencies. The practical realization of the PWM technique is described using performance criteria such as minimum pulse widths, peak carrier frequencies, and the current distortion View full abstract»

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  • Metallic particle movement, corona, and breakdown in compressed gas insulated transmission line systems

    Page(s): 816 - 823
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    A simplified computational algorithm has been developed to study the behavior of metallic particles in gas insulated transmission line (GITL) systems. The model provides an estimate of the effectiveness of particle trapping for a particular trap design at a given commissioning voltage. Results of measured breakdown probabilities of particle contaminated SF6 show fair agreement with calculated values. A computational model was developed to calculate the corona inception voltage due to conducting particle motion in GITL systems. The computed results for various parameters were in fair agreement with the measured values. A corona pulse pattern is computed and plotted using the same algorithm. Oscillographic records of the transient corona show that particle discharge is larger for long particles, and its magnitude increases with voltage level. Corona patterns obtained in the laboratory indicate that conducting particles can be detected in GITL systems and that the particle size can be determined through partial discharge measurements with AC voltage at different gas pressures View full abstract»

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  • Control techniques for improved high-speed performance of interior PM synchronous motor drives

    Page(s): 997 - 1004
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    Two control techniques to enhance the performance of the interior permanent magnet (IPM) drive over an extended speed range are described. The first technique is a feedforward compensation algorithm improving the performance of current regulators operating in the stationary reference frame. Speed-dependent back EMF and inductive voltage drops are compensated so that steady-state current errors are nulled at all speeds until current regulator saturation limits are encountered. The second technique is a flux weakening control algorithm that uses stator current components to prevent premature current regulator saturation, thereby improving the machine's torque production capabilities at high speeds. Both new algorithms require no additional feedback signals from the motor beyond those already used in the pre-existing controls, and they are relatively insensitive to variations in the machine parameters, despite their feedforward characteristics View full abstract»

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  • Simple efficiency maximizer for an adjustable frequency induction motor drive

    Page(s): 940 - 946
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    A new method of efficiency maximization that utilizes sensing of the third-harmonic component of air-gap flux is proposed. This signal is used to determine the resulting instantaneous position of the fundamental component of the air gap flux and, consequently, the torque- and flux-producing components of the stator current. In addition, the third harmonic signal is also used to determine the rotor speed. Hence, the output power of the machine can be calculated with only a single sensor wire attached to the neutral point of the machine. The flux-producing component can be readily adjusted to produce the minimum input power for a fixed amount of output power (fixed speed) View full abstract»

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  • Performance of fluorescent reflector inserts

    Page(s): 830 - 832
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    The authors present a summary of lighting test data taken on a number of different recessed fluorescent troffer luminaires that were modified by equipping the inside top and sides of the luminaire with insert panels of high-reflectance silver or aluminum in place of the usual white-painted metal. Photometry was utilized to compare before-and-after measurements of luminaire efficiency, lumen output, light distribution, and power input. The results indicate that the reflector inserts substantially increase luminaire efficiency. Data from tests of four-lamp luminaires that were modified by removing two lamps and a ballast and installing a reflector insert indicate that luminaire power dropped by about 50%, whereas total luminaire light output dropped by about 30%. The reflectors therefore improved the efficiency of the luminaire by over 20% View full abstract»

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  • Digital current regulation of field-oriented controlled induction motor based on predictive flux observer

    Page(s): 956 - 961
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    A new technique based on deadbeat control theory is proposed to control induction motor stator currents under field-oriented control. Stator currents and motor speed were measured. Rotor fluxes are predicted using a state observer with variable poles selection. Then, the pulse-width-modulated (PWM) pattern of the inverter is controlled such that the stator currents are exactly equal to the reference currents at every sampling instant. From the theoretical analysis, digital simulations, and experimental results, the following conclusions were made. The deadbeat controller permitted low current ripple with lower switching frequency, which, in turn, resulted in low torque ripple. The predictive state observer made possible the estimation of rotor flux with very low sensitivity to parameter variation and then contributed to performance improvement of conventional vector control View full abstract»

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  • Automated bus transfer control for critical industrial processes

    Page(s): 862 - 871
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    The techniques and methods for maintaining continuous electrical power to petroleum and chemical facilities from two or more utility feeders by an automated bus transfer logic controller (ABTLC) system are discussed. The purpose of this system is to reduce transients, torsional forces, inrush currents, and motor stress while maintaining continuous motor operation when the primary utility source experiences an interruption, and the operating facility transfers the motor load to an alternative source of electrical supply. The engineering studies, application considerations, motor control design requirements, installation, and operation of the automated bus transfer controller for a chemical facility are presented and discussed. The present bus transfer methods are reviewed. The effectiveness of these methods using typical buses is discussed. The influence of bus voltage and phase angle characteristics during bus transfer for determining the heat transfer technique is also analyzed View full abstract»

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  • Vector control of a synchronous reluctance motor including saturation and iron loss

    Page(s): 977 - 985
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    The application of vector control to a conventional synchronous reluctance motor (VCSynRM) is presented with emphasis on the effects of saturation and iron losses. It is shown experimentally that these parasitic effects can significantly influence the performance of a VCSynRM. A synchronous reference frame steady state model of SynRM including saturation and iron losses is developed. The behavior of a vector-controlled SynRM is analyzed based on the model. It is observed that saturation and iron losses can have a significant effect on the performance of a VCSynRM. To verify the validity of the model for vector control, a digital signal processor (DSP) based vector controller was built for a 7.5 hp SynRM to experimentally evaluate performance. Experimental results concerning optimal torque/ampere and optimal efficiency operation are shown to be in general agreement with the predictions of the model View full abstract»

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  • High-precision torque control of reluctance motors

    Page(s): 902 - 907
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    The high-precision torque control of a reluctance motor for servo applications is described. The prototype is a three-phase, eight-pole reluctance motor driven by a MOSFET inverter. The current control and the speed control are performed by software of the digital signal processor TMS 32010. The motor is supplied by sinusoidal current, and two current control methods are proposed. One is based on a vector control principle to achieve the linearity between current and torque, and another is developed to obtain the maximum torque/current ratio. Due to the saliency, the instantaneous torque contains a large ripple component. In the case of the test motor, the torque ripple was as much as 26% of the rated torque under sinusoidal current drive. The experiment showed that the ripple component could be reduced to 6% by superimposing a compensation current component on the current reference View full abstract»

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  • Failure analysis of low-voltage power and control circuits [power stations]

    Page(s): 833 - 840
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    Circuit protection and alternative approaches are often hard to quantify in advance of design. The author discusses two proven techniques-a probability method using a decision tree and a component damage method for predicting the weakest circuit component. These methods are applicable to circuits typically found in both fossil and nuclear generating stations and provide simple tools for selecting circuitry arrangements or components. The protection circuits used in probability analyses are not necessarily new developments but are representative of applications that exist in many plants. An improvement is indicated in each of the examples discussed View full abstract»

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  • A permanent magnet motor drive without a shaft sensor

    Page(s): 1005 - 1011
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    The authors describe a simple control for a permanent motor drive that provides a wide speed range without use of a shaft sensor. Two line-to-line voltages and two stator currents are sensed and processed in analog form to produce the stator flux linkage space vector. The angle of this vector is used in a microcontroller to produce the appropriate stator current command signals for the hysteresis current controller of the inverter so that near unity power factor can be achieved over a wide range of torque and speed. A speed signal is derived from the rate of change of angle of the flux linkage. A drift compensation program is proposed to avoid calculation errors in the determination of angle position and speed. The control system has been implemented on a 5 kW motor using Nd-Fe-B magnets. The closed loop speed control has been shown to be effective down to a frequency less than 1 Hz, thus providing a wide range of speed control. An open loop starting program is used to accelerate the motor up to this limit frequency with minimum speed oscillation View full abstract»

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  • An approach to position sensorless drive for brushless DC motors

    Page(s): 928 - 933
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    The authors describe a brushless DC motor without a position sensor. Variable speed is achieved by adjusting the average motor voltage, just like chopper control of DC motors. The position sensorless drive proposed is based on detection of the conducting interval of free-wheeling diodes connected in antiparallel with power transistors. This approach makes it possible to detect the rotor position over a wide speed range, especially at a lower speed. Experimental results obtained from a prototype brushless DC motor of 300 W rating are shown to confirm the validity of the sensorless drive from 45 to 2300 r/min. A starting procedure of the motor is also discussed because it is impossible to detect the rotor position at standstill View full abstract»

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  • A stator flux-oriented voltage source variable-speed drive based on DC link measurement

    Page(s): 962 - 969
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    The authors present a new control strategy for variable speed drives, which is aimed at improving or even replacing existing volts per hertz (V/f) open loop variable-speed drives. This strategy uses only the DC link current and voltage, which are readily available in a V/f drive for protection purposes, to implement closed loop flux and torque control. Stator flux and electromagnetic torque feedback signals are derived from the DC link voltage, the DC link current, and inverter switching states. Digital implementation is seen to be possible with slight modification on existing V/f drives. Practical considerations in implementing such a system are emphasized, and experimental results are presented to show the feasibility of the scheme View full abstract»

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  • Performance prediction of shaded pole induction motors

    Page(s): 876 - 882
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    The authors present an analysis for evaluating the performance characteristics of reluctance-augmented shaded pole motors. The proposed model is based on the d-q axis technique and is valid for steady-state and dynamic conditions. An efficient method of predicting the steady-state operating characteristics of the triac-controlled shaded pole motor is presented. This method calculates the currents and average torque as a function of conduction and control angles of the triac. The effect of critical parameters on the motor performance is investigated. Simulated results are compared with experimental values of a two-pole single phase test induction motor View full abstract»

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  • Capture of fine particles on charged moving spheres: a new electrostatic precipitator

    Page(s): 807 - 815
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    It was verified experimentally that electrostatic cleanup of fly ash dust is possible using the scrubbing action of charged copper particles with diameters 10-100 times the size of the dust particles. Results show that target efficiencies in excess of unity (up to 1.8) are possible as a result of the induced charge on the target particles. Power consumption to the precipitator was confirmed to be very small (~5×10-4 W). Values of the total collection efficiency of 0.65 (65%) were obtained for a precipitator zone length of 1.2 cm (in the direction of air flow) at air velocities of about 3 cm/s. This value decreased with increasing air flow rate. Collection efficiencies up to 0.99 (99%) are projected with a longer test section of at least 5.3 cm in length for low air velocities of about 3 cm/s, an electric field strength of 10.91 kV/cm, and 114.5 μm copper particles View full abstract»

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  • Application characteristics of permanent magnet synchronous and brushless DC motors for servo drives

    Page(s): 986 - 996
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    The permanent magnet synchronous motor (PMSM) and the brushless DC motor (BDCM) have many similarities; they both have permanent magnets on the rotor and require alternating stator currents to produce constant torque. For application considerations, these two motor drives have to be differentiated on the basis of known engineering criteria. Some of the criteria used to assess these two machines include power density, torque per unit current, speed range, feedback devices, inverter rating, cogging torque, ripple torque, and parameter sensitivity. Guidelines for the appropriate machine to be used for a given application are given based on the results of the criteria View full abstract»

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  • Pyroelectric detectors and their applications

    Page(s): 824 - 829
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    The authors review the principles of operation of pyroelectric detectors. The equations for current responsivity, voltage responsivity, noise, noise equivalent power, and detectivity are derived from the fundamental thermodynamic model of a pyroelectric detector. The frequency-dependent current and voltage responsivities are explained. Factors influencing the choice of pyroelectric material for various applications are summarized. The possibilities of various new applications and the developments of pyroelectric detectors are discussed. A laboratory prototype demonstration system has been built using an ELTEC detector type 5192. For a high signal-to-noise ratio, an electric charge integration technique is applied. High-precision operational amplifiers are used for high-quality signal conditioning. The pyroelectric detector consists of two parallel opposed dual lithium tantalate pyroelectric single crystals with a junction FET source follower sealed in a standard TO-5 housing View full abstract»

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Aims & Scope

The scope of the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS includes all scope items of the IEEE Industry Applications Society, that is, the advancement of the theory and practice of electrical and electronic engineering in the development, design, manufacture, and application of electrical systems, apparatus, devices, and controls to the processes and equipment of industry and commerce; the promotion of safe, reliable, and economic installations; industry leadership in energy conservation and environmental, health, and safety issues; the creation of voluntary engineering standards and recommended practices; and the professional development of its membership.

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