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Industry Applications, IEEE Transactions on

Issue 4 • Date Jul/Aug 1994

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Displaying Results 1 - 25 of 37
  • Using utility demand-side management programs to spur the development of more efficient appliances

    Page(s): 877 - 882
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    Traditionally electric and gas utilities have promoted the development of more efficient appliances through research institute R&D programs and through utility incentive programs which provide incentives for efficient commercialized products. A third mechanism has evolved: multiutility incentive programs which target higher levels of efficiency than the best products on the market. One program of this type is now underway for refrigerator/freezers. A second program has just begun for residential clothes washers. Further efforts are likely as evidenced by a research project which identified major opportunities for more efficient appliances and by the formation of a new organization to develop and promote programs of this type. This paper summarizes each of these efforts View full abstract»

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  • Digital control for brush DC motor

    Page(s): 883 - 888
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    In home appliances applications the brush DC motor, driven by a chopper, can be controlled by a standard microcontroller. However people often consider the microcontrollers as not suitable for the power environment because of their limited computing speed or noise immunity problems. This paper shows how a cost effective digital motor drive can be designed by combining a chopper and an 8 bits microcontroller: the speed is simply controlled through direct voltage compensation and motor power limitation. The microcontroller implements both motor control and interface functions of the application: it replaces the analog circuits of the conventional motor control. Performances and practical results are given for a 300 W/12000 RPM motor drive View full abstract»

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  • Damaging long-term overvoltages on industrial capacitor banks due to transformer energization inrush currents

    Page(s): 1107 - 1115
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    This paper discusses the issues concerning industrial power systems with large capacitor banks and the energization of large furnace power transformers. The application of the capacitor banks could tune the system to a frequency that is excited by the furnace transformer energization current. Examples of situations occurring in industrial systems are shown with field-measured data. Transient and harmonic simulations are also shown describing the phenomena. The effects on the capacitors caused by the overvoltages that are created due to the resonant conditions are discussed. The paper also addresses relevant capacitor standards and how they are related to this type of system phenomena View full abstract»

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  • Basic consideration of vibration suppression and disturbance rejection control of multi-inertia system using SFLAC (state feedback and load acceleration control)

    Page(s): 889 - 896
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    SFLAC (state feedback and load acceleration control) is proposed for vibration suppression and disturbance rejection control of a multi-inertia system. A multi-inertia system is the model of a steel rolling mill, a flexible arm, a large-scale space structure, etc., and its control will be an important problem in the future of motion control. The main idea of SFLAC is to control the load acceleration which can be estimated by the state observer including the disturbance estimation. A simple PI speed controller and SFLAC based on the reduction models using two and three inertia moments are designed. The effectiveness of SFLAC is demonstrated showing some simulation results View full abstract»

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  • NOx removal by a pipe with nozzle-plate electrode corona discharge system

    Page(s): 856 - 861
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    The effects of additional gas composition on the corona discharge characteristics in a pipe with nozzle electrode system and the NOx removal characteristics for flue gases are experimentally investigated. The additional gas consists of a mixture of Na+O2+NH3 and a small amount of Ar or CO2, and is introduced to the flue gas stream from the pipe electrode through the corona discharging zone at the tip of nozzles. The results show that corona discharge characteristics and modes are significantly influenced by the composition of the additional gas mixture. Both NOx reduction rate and energy yield of NOx removal increase with decreasing corona discharge input power. NO reduction rate and energy yield can be optimized by the type of the additional gas mixture and the flow rates View full abstract»

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  • Molecular dielectrophoresis of biopolymers

    Page(s): 835 - 843
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    Dielectrophoresis (DEP) has found wide applications in manipulations of micrometer-sized particles such as biological cells. However, it has been considered less effective for nanometer-sized particles such as biological macromolecules where DEP effects may be overwhelmed by Brownian motion. Here, the authors use the fluid integrated circuit (FIC) concept to fabricate micrometer-sized electrodes, with which a very high-intensity, steady-state, high-frequency field, over 1×106 V/m at 1 kHz to 10 MHz, is created. The observation of molecular DEP using avidin (68 kD) and other biopolymers is made, and it is found that DEP occurs at the field strength of 0.4-1.0×106 V/m, which is substantially lower than DEP theory predicts. As applications of molecular DEP, a novel molecular patterning method and “dielectrophoretic chromatography” are proposed. In the latter, biopolymer solution is moved through a high-intensity field region created in a FIC, and the polymer is analyzed and/or separated by the difference in the DEP attraction View full abstract»

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  • Evaluation of harmonic levels in electrical networks by statistical indexes

    Page(s): 1116 - 1126
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    The problem of evaluation and forecasting of harmonic pollution levels in power networks supplying many nonlinear power devices is generally solved resorting to the “worst-case” criterion, which consists of the arithmetic sum of harmonic current amplitudes (i.e., in-phase vectorial sum) at network buses. However, due to the fact that harmonics (particularly those of a higher order) may have significantly different phase angles, this assumption has been proven to be too conservative in most practical applications. More realistic evaluations can be obtained by regarding the distorting loads as harmonic-current sources, characterized by probability density functions of both magnitude and phase. In this paper, the problem of harmonic pollution in electrical networks is dealt with using the above-mentioned simplified procedure. In particular, a comparative study is carried out on the effectiveness of these expressions, which have been proposed to simplify evaluation and forecasting of harmonic pollution levels in AC power networks View full abstract»

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  • Deadbeat flux level control of direct-field-oriented high-horsepower induction servo motor using adaptive rotor flux observer

    Page(s): 954 - 962
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    A method for the deadbeat flux level control of direct-field-oriented high-power induction servo motor drives has been developed that employs an adaptive rotor flux observer. The observer is a full-order type and is used not only in the direct-field-oriented controller, but also to determine the stator and rotor resistances of the servo motor. The observer reduces the sensitivity of a deadbeat controller to fluctuations in the motor parameters. The main advantage of this method is that it improves the efficiency of an induction servo motor without sacrificing dynamic performance. This paper describes the method as well as the fundamental characteristics of the system derived from experimental and simulation results View full abstract»

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  • Investigation of fault modes of voltage-fed inverter system for induction motor drive

    Page(s): 1028 - 1038
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    The reliability of power electronics systems is of paramount importance in industrial, commercial, aerospace, and military applications. The knowledge about the fault mode behavior of a converter system is extremely important from the standpoint of improved system design, protection, and fault tolerant control. This paper describes a systematic investigation into the various fault modes of a voltage-fed PWM inverter system for induction motor drives. After identifying all the fault modes, a preliminary mathematical analysis has been made for the key fault types, namely, input supply single line to ground fault, rectifier diode short circuit, inverter transistor base drive open, and inverter transistor short-circuit conditions. The predicted fault performances are then substantiated by simulation study. The study has been used to determine stresses in power circuit components and to evaluate satisfactory post-fault steady-state operating regions. The results are equally useful for better protection system design and easy fault diagnosis. They will be used to improve system reliability by using fault tolerant control View full abstract»

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  • Galerkin analysis of electrothermal instabilities in plane liquid layers

    Page(s): 862 - 876
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    The stability of a horizontal layer of poorly conducting dielectric liquid subjected to a unipolar injection of ions and a thermal gradient is studied. Ions arising from injections and dissociation are supposed to have the same nature. Ionic mobility and electric permittivity are allowed to vary linearly with temperature. The linear stability analysis has been carried out by means of a Galerkin method with one and two trial functions. A single trial function provides useful analytical relations between parameters for the neutral stability surface. A second trial function is necessary to account for the existence of overstability in the absence of a thermal gradient and to achieve better accuracy in the solution View full abstract»

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  • Synchronous drive performance of brushless doubly-fed motors

    Page(s): 963 - 970
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    This paper presents studies of the steady-state performance of the brushless doubly-fed machine for adjustable-speed drive applications. The equivalent circuit and basic performance equations are presented followed by a proven technique for the solution of the least restrained form of the equations. Model predictions and experimental results are given. The studies show that the machine acts like both a synchronous motor, with power factor adjustable by control winding excitation, and a slip-ring induction machine with slip power recovery and a low converter rating. The model is suitable for development of control schemes and performance index optimization View full abstract»

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  • Optimal pulsewidth modulation for AC servos and low-cost industrial drives

    Page(s): 1039 - 1047
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    An optimal pulsewidth modulation method for inverters is described in which the durations of switching subcycles are considered as optimization variables, a subcycle being the time sequence of three consecutive switching state vectors. Operation at variable subcycle duration entails a prediction of the controlling reference voltage vector. It is a special advantage that the optimization and prediction can be carried out off line. The optimal technique exhibits high dynamic performance. It can be used for synchronized and asynchronous modulation in a wide range of switching frequencies. The optimization reduces the harmonic currents at a given switching frequency. The Fourier spectrum lacks dominant carrier frequencies. Hardware implementation cost compares with existing nonoptimal modulation methods View full abstract»

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  • Thermal considerations in specifying dry-type transformers

    Page(s): 1090 - 1098
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    In 1944, the hottest spot temperature allowance for ventilated dry-type transformers was established as 30°C for 80°C average winding temperature rise and IEEE standards use a constant 30°C hottest spot temperature allowance for all insulation temperature classes and all transformer ratings. Thermal tests under different loading conditions were performed on a prototype 2500 kVA ventilated dry-type transformer and six full-size test coils with imbedded thermocouples in the windings. The test data indicated that the hottest spot temperature allowance used in IEEE and IEC standards is too low for ventilated dry-type transformers above 500 kVA. It is impossible to design ventilated dry-type transformers above 500 kVA with an average temperature rise of 150°C exceeding the permissible hottest spot temperature rise of 180°C due to large thermal gradients. The average temperature rise for ventilated dry-type transformers above 500 kVA with 220°C insulation temperature class should be 120°C. IEEE standards should require measurement of hottest spot temperature rise on prototype transformers or windings as a design test to qualify a design family and the manufacturer's mathematical models. This is especially important for ventilated dry-type transformers rated for nonsinusoidal load currents. The specification suggested in the paper should be used until IEEE standards are revised View full abstract»

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  • The energy consumption of desktop computers: measurement and savings potential

    Page(s): 1065 - 1072
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    The energy consumption of desktop personal computers was studied at three Canadian Federal Government sites, and the potential for energy savings through power management investigated. The power draw of computers and their peripherals was measured using a portable meter, and use profiles were recorded using custom software. The measured plug loads were considerably lower than nameplate ratings. Use profiles from 94 computers indicated that there were long periods during both night and day when the computers were turned on but not being used, and it was predicted that significant energy savings could be achieved if electricity consumption was more closely tailored to actual usage. Two methods of realizing these savings were tested in the field. Stickers reminding users to switch off computers when they were not being used produced reductions in mean computer energy consumption of 14% over an eight week period. However, these savings diminished with time. An automatic power management system designed to switch off computers and peripherals after a user-specified period of inactivity produced reductions in mean computer energy consumption of 63%, while visual display unit mean energy consumption was reduced by 82%. These savings were maintained over an eight week period View full abstract»

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  • The trajectory tracking approach-a new method for minimum distortion PWM in dynamic high-power drives

    Page(s): 1048 - 1057
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    Feedforward pulsewidth modulators generate volt·second differences between the controlling reference signal and the switched output waveform during transient operation. This dynamic modulation error is particularly pronounced at low switching frequency, e.g. with modern high-power GTO inverters. The compensation of this error is a key requirement when designing an optimal pulsewidth modulator for these applications. The trajectory tracking approach uses the steady-state trajectories of the current vector, computed from the optimal switching sequences, as templates. A tracking controller counteracts if the actual current vector deviates from this given path at transient operation. A decomposition of the current vector trajectory into its components enables, in addition, the identification of the instantaneous fundamental current, permitting the implementation of a fast current control system. Oscillograms from a 30 kW model induction motor drive demonstrate the high quality in terms of dynamic performance and minimum harmonic distortion obtained with a three-level inverter at only 200 Hz switching frequency View full abstract»

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  • Modeling and vector control of synchronous reluctance motors including stator iron loss

    Page(s): 971 - 976
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    The influence of the stator iron loss cannot be neglected since the high-speed operation and precision torque control of AC motors are required. This paper presents the modeling and vector control of synchronous reluctance motors including the stator iron loss. The stator iron loss is modeled by additional windings on the d-q axes, and is introduced as an equivalent iron loss resistance in voltage equations under the assumption that the losses in the stator core are produced in equivalent eddy current windings on d-q axes. The equivalent iron loss resistance is inserted in series with exciting inductance, and the d and q axes interfere with each other through the equivalent iron loss resistance. To achieve vector control, the d-q axis currents are decoupled by nonlinear control voltages. As a result, the instantaneous torque control scheme is equal to that of a DC machine and the torque control is simplified View full abstract»

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  • A new approach to motor condition monitoring in induction motor drives

    Page(s): 905 - 911
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    A new method for condition monitoring of an electrical machine is proposed. The method uses the power leads to the machine itself as the communication link between the sending station located within the machine and the receiving station located remotely outside the machine. The required communication circuit to realize data transmission in both the cases of the ordinary 60 Hz power line and the special PWM inverter-fed power line is then constructed. The communication circuit uses an asynchronous serial communication protocol and an FSK modulation for realizing frequency multiplexing in the power line. An on-line winding temperature monitoring system for an inverter-fed induction machine is constructed using this power line communication link. Experimental results demonstrate satisfactory operation of the system View full abstract»

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  • Wide-speed operation of interior permanent magnet synchronous motors with high-performance current regulator

    Page(s): 920 - 926
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    Interior permanent magnet synchronous motors can be applied to applications requiring wide-speed operation. The current vector control algorithm of an interior permanent magnet synchronous (IPM) motor for constant power operation over the base speed is proposed. As the available voltage controlling the armature current vector is small in the flux-weakening constant power region, the current vector sometimes becomes uncontrollable in transient operations because of the current regulator saturation. The high-performance current regulator is also proposed to improve the current responses in the flux-weakening region, which includes the decoupling current controller and the voltage command compensator. The control performances are confirmed by several drive tests with respect to the prototype IPM motor View full abstract»

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  • Survey of energy and power usage in copiers, duplicators, and electronic reprographic devices

    Page(s): 1058 - 1064
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    This report investigates power demand and energy consumption of copiers, duplicators, and electronic reprographic devices that are widely used in the office place. Data are presented on power, energy per copy, and energy consumption trends over a 15 year period. The dependence on machine speed and duty cycle is also examined, and the effect of emerging digital and color technologies on energy and power usage is briefly considered View full abstract»

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  • Five-level GTO inverters for large induction motor drives

    Page(s): 938 - 944
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    The development of large induction motor drives with low torque ripple and fast dynamic response for new or retrofit applications has been limited by the device ratings and problems of series connections. This paper investigates the use of a five-level GTO voltage-sourced inverter for large induction motor drives. The advantages of such a drive are that single GTO thyristors may be used at each level, thereby avoiding the need for series connection of the thyristors. The thyristors are well protected from overvoltages by the clamping action of the DC supply capacitors. The disadvantages are that each DC level requires a separate supply, four in the case of the five-level inverter, and that the devices are not equally loaded. This paper reviews the basic operation of the five-level inverter and possible PWM voltage/frequency control techniques for the specific application of induction motor drives. The simulation results clearly show the unequal loading of the devices and the need for independent voltage supplies for the five levels. It is shown that a combination of several PWM techniques offers the best solution for the drives application. The conclusions indicate that large induction motors with ratings up to 22 MVA, 7.46 kV may be supplied by the five-level inverter using available 4.5 kV, 3.0 kA GTO thyristors. The recommended supply for such an inverter with full regenerative operation over the complete speed range is four, four-quadrant converters in a quasi-24-pulse configuration View full abstract»

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  • Performance analysis of three-phase inverters controlled by synchronous delta-modulation systems

    Page(s): 1016 - 1027
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    Synchronous delta-modulation systems are used to control resonant voltage link inverters, where switching has to be synchronized with the zero crossings of the link voltage. This paper shows that output current harmonic distortion and average switching frequency of such systems can be calculated analytically in spite of the quasistochastic behavior of the modulators output. Under the assumption of constant link frequency and large ratio of link to output frequency, results are derived for three-phase sigma-delta modulation, space-vector based sigma-delta modulation, and current-regulated delta modulation. The results hold for any shape of the inverter input voltage (including DC). The output current harmonic distortion of resonant link inverters is compared with conventional hard switching PWM inverters View full abstract»

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  • Series compensated PWM inverter with battery supply applied to an isolated induction generator

    Page(s): 1073 - 1082
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    This paper proposes a new series compensated induction generator/battery supply topology which provides a constant voltage and frequency at the terminals, allowing minimum current harmonic distortion while at the same time providing a source and sink of real and reactive power. With appropriate control of the reactive power, the speed of the generator is allowed to vary within a relatively wide range. This technique can be further expanded by applying AC capacitors in parallel with the load to lessen the burden of the PWM inverter. Both simulation and experimental results are in agreement with the theory which leads to the conclusion that the system could be feasible for isolated power generation systems (wind, hydro, diesel, or hybrid generation) View full abstract»

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  • Design of DC traction motor drives for high efficiency under accelerating conditions

    Page(s): 1134 - 1138
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    A design of a DC series motor drive that minimizes both armature and field winding copper losses is presented. A nonlinear feedback is first applied to linearize the system. A closed-form expression of optimal control that minimizes the total copper losses is derived using Pontryagin's Maximum principle. A computer simulation of a conventional drive and the energy-efficient drive of the same size are presented. The energy consumption comparison is made to show the effectiveness of the control law. Finally, implementation techniques of the energy-efficient drive are discussed View full abstract»

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  • History of electric vehicles in General Motors

    Page(s): 897 - 904
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    This paper traces the efforts by General Motors in the area of electric and hybrid propulsion systems. Propulsion systems developed for different vehicles are described and performance achieved is presented. The activities to commercialize electric vehicles are briefly examined. The paper concludes with recommendations of technologies to be applied in propulsion systems to bring the performance of the electric vehicles to the state that is viable for mass acceptance View full abstract»

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  • A low ripple power supply for high-current magnet load

    Page(s): 1006 - 1015
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    The magnet power supplies provide precisely controlled current to the magnets in particle accelerators. As the research in high-energy physics progresses, the required precision of the magnet current is increasing rapidly. Existing magnet power supplies for high-current applications cannot meet the present and future demands. This paper proposes a new magnet power supply for high-current magnets. The proposed system integrates a switch-mode ripple regulator with a phase-controlled rectifier. The results from this paper indicate that the proposed system can provide a magnet current with less than 10 ppm harmonic content and can be expected to have fast dynamic response. In this paper, the general description of the power circuit and system control configuration is presented. Fourier analysis is applied to investigate the harmonic content of the magnet current. The theoretical analysis is verified experimentally. A design example is given 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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