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Industry Applications, IEEE Transactions on

Issue 5 • Date Sept.-Oct. 1998

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Displaying Results 1 - 25 of 35
  • Torque-ripple minimization in switched reluctance machines over a wide speed range

    Page(s): 1105 - 1112
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    A torque-ripple minimization technique for switched reluctance motors (SRMs) is presented. The technique is particularly suitable for applications requiring wide speed range of operation. A new, simple, yet efficient commutation strategy is proposed. The commutation algorithm is speed dependent and uses a real-time approach instead of precalculated stored data. The model used for the SRM in the controller can also be updated in real time. Simulation and experimental results verify the feasibility of implementing the proposed control algorithm in real time. View full abstract»

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  • Direct electrostatic levitation and propulsion of silicon wafer

    Page(s): 975 - 984
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    A new type of contactless wafer manipulator, featuring “direct electrostatic levitation and propulsion of silicon wafer (DELP-SW)”, has been successfully developed. The novel aspect of this manipulator is that a silicon wafer can be directly levitated and driven via electrostatic forces. In this paper, a brief review of basic principles is presented. This is followed by a description of the structure of a prototype DELP-SW mechanism, including electrode design, position feedback control method, driving principle, and the operational procedure. Experimental results, which demonstrate completely contactless transportation of an 8-in silicon wafer, are also presented View full abstract»

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  • A frequency approach for current loop modeling with a PWM converter

    Page(s): 1000 - 1014
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    A new method based on a frequency approach is used to model a DC permanent magnet actuator driven by a pulsewidth modulated amplifier as a transfer function. This paper investigates two carriers used in industrial applications with analog or digital control. The accurate model presented takes into account the supply amplifier with the motor dynamics and includes the input control voltage sampling effect. Advantages and limitations of both carriers and control signals are discussed, and information about harmonic angles, magnitudes, and distortion are provided. The validation of the pulsewidth modulated model is carried out through simulations and experiments of both open and closed current loop systems with the effect of current ripple View full abstract»

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  • Direct-coupled multilevel cascaded series VAr compensators

    Page(s): 1156 - 1163
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    Series VAr compensators based on force-commutated static power converters are proving to be a viable alternative to shunt compensators as a means of enhancing power transmission and distribution capability. This paper proposes a converter structure, based on a multilevel cascade of single-phase converters, which can be coupled to the transmission system without transformers. The individual converters are switching at very low frequencies, resulting in high efficiency, and are fed from independent self-controlled DC capacitor buses. Advantages of the proposed series compensator include low injected voltage harmonic distortion and fast response to changes in the compensation level. Pattern generation options are presented. Gating and control schemes are discussed. Simulation results are verified experimentally View full abstract»

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  • Traction control of electric vehicle: basic experimental results using the test EV “UOT electric march”

    Page(s): 1131 - 1138
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    The most distinct advantage of the electric vehicle is its quick and precise torque generation. However, most electric vehicles developed to date have not yet utilized this feature. In this paper, two novel traction control techniques of an electric vehicle using this advantage are proposed. One is the model-following control and the other is the optimal slip ratio control. The basic effectiveness of the proposed methods is demonstrated by real experiments using the DC-motor-driven test vehicle “UOT (University of Tokyo) Electric March” View full abstract»

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  • Performance analysis of an asymmetrical phase-converter-fed induction motor

    Page(s): 1049 - 1058
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    Of the various types of single-phase-to-three-phase static power converters used to interface a three-phase motor to single-phase supply, one simple type uses an open delta connection of a sinusoidal supply and a pulsewidth modulated (PWM) waveform to feed the motor. This paper presents an analysis of the performance of the three-phase motor when fed from such an asymmetrical supply. The analysis is based on the steady-state approximate-equivalent circuit of the motor, using the method of symmetrical components. The analysis is directed toward prediction of motor phase and line currents, along with the nature of generated torque. The computer-simulated waveforms are presented and compared with results from tests on a laboratory setup View full abstract»

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  • A high-performance generalized discontinuous PWM algorithm

    Page(s): 1059 - 1071
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    In this paper, a generalized discontinuous pulsewidth modulation (GDPWM) method with superior high modulation operating range performance characteristics is developed. An algorithm which employs the conventional space-vector PWM method in the low modulation range, and the GDPWM method in the high modulation range, is established. As a result, the current waveform quality, switching losses, voltage linearity range, and the overmodulation region performance of a PWM voltage-source inverter (PWM-VSI) drive are optimized online, as opposed to conventional modulators with fixed characteristics. Due to its compactness, simplicity and superior performance, the algorithm is suitable for most high-performance PWM-VSI drive applications. This paper provides detailed performance analysis of the method and compares it to the other methods. The experimental results verify the superiority of this algorithm to the conventional PWM methods View full abstract»

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  • Reduction of NOx from natural gas combustion flue gases by corona discharge radical injection techniques [thermal power plant emissions control]

    Page(s): 934 - 939
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    An experimental investigation has been conducted to reduce NOx in natural gas combustion flue gases by means of corona-discharge-activated ammonia/methane radical injection methods. Multihole-type corona radical injectors are used in the present investigation. Experiments were conducted for the simulated natural gas combustion flue gas (N2:O2:CO2:NO=83.96:8:8:0.04) flow rate from 1 to 200 L/min, the activation voltage (DC or pulse) from 0 to 40 kV, and the Ar-ammonia or Ar-methane mixture gases flow rate from 0 to 200 mL/min. The results show that the NOx reduction increases with increasing activation voltage and nonmonotonically depends on ammonia/methane stoichiometry View full abstract»

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  • A novel two-phase BPM drive system with high power density and low cost

    Page(s): 1072 - 1080
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    A novel brushless permanent-magnet (BPM) motor drive system is proposed in this paper. The basic motor structure consists of a stator with four salient pole pieces and a six-pole permanent-magnet rotor. The proposed drive system, using four switches, fully utilizes the stator ampere turns by providing 180 electrical degree bipolar current conduction. Hence, the use of motor materials is maximized and very high power density is achieved. In addition, the quasi-square-wave back EMF and matching current waveshape guarantee minimum peak current stress on the drive. The low stress on the power devices and efficient use of active materials result in a drive system with a lower cost than conventional three-phase BPM drives of comparable output power. The advantages of the proposed system over three-phase BPM motor drives is illustrated using sizing analysis, finite-element analysis, time-domain simulations, and experimental studies. It can be expected that a variety of industrial applications will follow up on this new technology View full abstract»

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  • A summary of the IEC protection against electric shock

    Page(s): 911 - 922
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    This paper provides a summary of the IEC protection against electric shock. This protection is provided by appropriate basic measures as follows: (1) for protection both in normal service and in case of a fault (against both direct and indirect contact), use low and safe voltage of 50 V and below; (2) for protection in normal service (against direct contact), use insulation and/or enclose live parts or use isolation distance; and (3) for protection in case of a fault (against indirect contact), prevent conducting parts not normally energized from becoming live. This is accomplished by grounding and automatic disconnection of the supply, by use of Class II equipment (as double or equivalent insulation), or by separating the supply from ground, IEC publication 364-4-41 “Electrical installations of buildings”, (Part 4, Chapter 41) classifies types of system grounding as TN-system, TT-system, and IT-system. Development of this summary is based on actual hazard risk analysis of potential incidents to suggest criterion by which the appropriate measures can be applied to avoid or mitigate injury or damage View full abstract»

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  • A thyristor phase-controlled voltage-source converter with bidirectional power flow capability

    Page(s): 1147 - 1155
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    A new line-commutated thyristor phase-controlled voltage-source power converter (VSC) with bidirectional power flow capability is proposed and studied. The proposed power converter has the same structure as the pulsewidth modulation (PWM) VSC, however, the switching devices are not self-commutated devices but line-commutated thyristors, and the converter is operated not with PWM but with six-pulse phase control. As in the case of the PWM VSC, the proposed converter provides a bidirectional DC-side current capability and, hence, the DC-side voltage can be regulated at its desired value. The harmonics are much smaller than those in the conventional thyristor phase-controlled current-source power converter. The proposed converter can be useful as a utility interface power converter, especially in high-power voltage-source inverter motor drive systems with regenerative braking View full abstract»

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  • Factors and intermediates governing byproduct distribution for decomposition of butane in nonthermal plasma

    Page(s): 967 - 974
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    Plasma chemical decomposition of butane was investigated with a ferroelectric parked-bed plasma reactor to obtain the information on the fundamental chemical processes occurring in nonthermal plasma. It has been shown that butane decomposition efficiencies are higher in nitrogen rather than in air. This fact suggests that energy transfer from hot electrons to butane is mainly responsible for the initial decomposition of butane. Nitrogen incorporation was observed for acetonitrile only in dry nitrogen and for nitromethane in air. Barium titanate and water have been shown to act as monooxygen transfer agents in nitrogen. Lattice oxygen atoms in barium titanate can be consumed in the formation of N 2O and CO, depending on reaction conditions. Water is much more reactive than barium titanate as an oxidant in nonthermal plasma, and it can oxygenate butane to butanols, epoxidize 1- and 2-butenes, and oxidize CO to CO2. Water, which has a dichotomic nature regarding oxygenation/hydrogenation in plasma, can act as a hydrogen source toward alkyl radicals formed in the initial decomposition of butane. In air, triplet oxygen molecules are the most reactive oxygen source in the presence or absence of water and carbon balance can be improved with suppression of byproducts due to promoted autoxidation processes View full abstract»

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  • Sampling of discontinuous voltage and current signals in electrical drives: a system approach

    Page(s): 1123 - 1130
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    Various methods for sampling of voltage and current signals in electrical drives are analyzed and compared, two new methods for sampling the discontinuous voltage and current signals in a pulsewidth modulation drive are proposed. The methods are based on sampling the instantaneous values and locally averaged values (over one carrier period) of signals. Analytical expressions for adjustment of digital current regulators and achievable bandwidths with the various sampling methods are derived. The results are experimentally verified View full abstract»

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  • Analysis and mitigation of voltage disturbances at an industrial customer's corporate campus

    Page(s): 893 - 896
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    This paper presents the analysis of voltage sag data collected over several years at an industrial customer's corporate campus. Facilities on the campus include office buildings, pilot plants, R&D laboratories, chiller plants and boiler plants. The paper examines the “cause and effect” of voltage dips to the processes at the campus. It also details what the utility and the industrial customer did, or is doing, to mitigate additional dips to the campus. The determination of the final configuration of the power distribution system and its effect on the customer's power quality is also discussed View full abstract»

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  • Design and field-weakening performance of a synchronous reluctance motor with axially laminated rotor

    Page(s): 1035 - 1041
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    Axially laminated reluctance motors can be designed to have high saliency and so offer very good performance in terms of torque capacity, power factor and efficiency. This paper presents the design and performance of a 7.5 kW four-pole machine, using thin rotor laminations, which achieved an unsaturated saliency ratio of 12.5. Finite-element analysis is used to predict machine parameters, paying special attention to modeling of the thin rotor elements and to saturation effect on the d axis. Computed parameters are compared with test measurements, showing good agreement. Load tests with 50Hz supply confirm the expected performance characteristics, but also show the occurrence of additional losses associated with the axially laminated rotor construction. A design modification to reduce the extra losses is demonstrated. A detailed investigation of field-weakening performance is reported, showing constant-power characteristics and good agreement between predicted and measured performance over a speed range of 2.25:1 above base speed View full abstract»

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  • Voltage and current sensing in power electronic converters using sigma-delta A/D conversion

    Page(s): 1139 - 1146
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    This paper presents a novel approach to voltage and current measurement in power electronics using a sigma-delta A/D converter. The system converts the analog input signal into a clocked stream of low-resolution digital data. By averaging this stream of data over a time interval that can be defined individually for each switching cycle, a high-resolution measurement of the input signal is obtained. Harmonic distortion of the waveform to be measured (caused by the switching of the power converter) is inherently filtered out due to proper choice of the averaging interval. The system is insensitive to noise and ringing caused by EMI or cable oscillations. The simplicity of the analog part of the sigma-delta A/D converter and its synchronous operation make it possible to integrate the whole sigma-delta converter into a small application specific integrated circuit (ASIC). The stream of low-resolution digital data at the output of the ASIC can be transmitted to the control electronics via a fiber-optic link that also insulates the sensing point from the control electronics, so that noninsulating sensors can be used View full abstract»

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  • Submicron charged dust particle interception by charged drops

    Page(s): 985 - 991
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    This paper presents a numerical algorithm for simulating the trajectories of charged dust particles moving horizontally in the vicinity of a free-falling, oppositely charged liquid droplet. The trajectories are calculated in three-dimensional space relative to the liquid droplet. This approach enables the determination of the envelope of possible trajectories which will result in collection on the droplet. The air drag, electrical, and gravitational forces are taken into account. A number of different models for the air flow around a spherical droplet are compared. The algorithm is used to determine the collection efficiency, according to a newly proposed definition, for a single charged spherical collector View full abstract»

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  • Destruction of volatile organic compounds used in a semiconductor industry by a capillary tube discharge reactor

    Page(s): 953 - 966
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    Nonthermal plasma technologies offer an innovative approach to the problem of decomposing various volatile organic compounds (VOCs). The authors focused on DC capillary tube discharge plasma reactors to study the decomposition/destruction efficiency for toluene, EGM, trichloroethane and trichloroethylene at 50-2300 ppm levels in dry air. The effects of gas flow rate, VOC concentration and reactor operating conditions on decomposition and analysis of reactant conversion for each VOC were investigated. The results show that VOC destruction efficiency as high as 90% can be achieved, even under a short residence time (3.8 ms) with a destruction energy efficiency of up to 95 g (VOC)/kWh. Laboratory-scale plasma technology was successfully demonstrated for its potential application for VOC control in the semiconductor clean-room environment View full abstract»

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  • Retrofitting pipelines with induction motors

    Page(s): 1175 - 1184
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (204 KB)  

    This paper includes a discussion of design considerations, test, and application of a large stiff-shaft two-pole motor designed for fixed or adjustable-frequency drive (AFD) of pumps for a pipeline retrofit. A rotor-dynamics analysis of the rotor bearing system is presented for the as-built design and for alternate bearing designs. Test data is presented for complete shop tests with the motor and drive system. The project consisted of 22 motors plus two spares rated 3000 HP at 1.15 service factor and 3600 r/min at 60 Hz. These motors, rated 4000 V, are for use at variable speeds and torque from 23.5 to 60 Hz. A second, more recent project consisting of 18 motors and one spare rated 3000 HP at 1.15 service factor and 3600 r/min at 60 Hz is also briefly described in the paper. These 4000 V motors are for use at variable speeds and torque from 24 to 66 Hz View full abstract»

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  • Harmonic interaction between 1500 kVA supply transformer and VFD load at an industrial plant

    Page(s): 897 - 903
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    The application of variable-frequency drives (VFDs) in industrial and commercial facilities has seen a tremendous increase. However, when multiple VFDs are fed from one dedicated power transformer, care should be taken not to drive the transformer into saturation. At one industrial location, nine VFDs rated at 200 HP each, and fed from a single 1500 kVA air-cooled transformer, showed saturation phenomenon, which had the potential of causing serious damage to the transformer. This paper discusses the input AC current waveform asymmetry caused by the interaction of the transformer and the nine 200 HP VFD load fed from it. The term waveform asymmetry is used when the positive half of the input AC current cycle is not equal to the negative half of the input AC current cycle. This results in the existence of DC components along with even harmonics in the input at current waveform. The various tests and the eventual solution to the waveform asymmetry caused by the VFDs is presented. The value of the inductance in the DC smoothing inductor (DC-link choke), which is included as part of the VFD, was found to contribute significantly to the waveform asymmetry. Experimental results showing the performance of a reconfigured DC-link inductor to reduce its interaction with the power transformer are presented View full abstract»

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  • Electroosmotically enhanced drying of biomass

    Page(s): 992 - 999
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    A laboratory system for experimentally characterizing electroosmotic dewatering of biomass has been developed. The system was used to investigate the dewatering at both constant voltage and constant current of two biomass materials, organic humus with peat and composted wastewater sludge (WWS). The moisture content of humus decreased to 22.5% from an initial value of 44.3% wet basis (wb) after 2 h 10 min of electroosmosis at 50 V across a 2.9 cm thick bed, whereas that of sludge decreased to 53.5% from an initial value of 68.4% after 2 h 20 min at 40 V across the bed. The electrical energy required to remove 1 kg of water by constant-voltage electroosmosis of humus varied from 23% to 61%, in the voltage range of 10-50 V, of the thermal energy required to change the same quantity of free water from liquid to vapor state. For WWS, the energy remained constant at a higher value of 88% over the 20-40-V range studied. The flowrate of liquid water out of the bed at constant voltage linearly increased with the applied electric field, and the electrical energy expended in the constant-current dewatering mode was seen to be a quadratic function of time as predicted by classical electrokinetic theory View full abstract»

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  • Two-channel switched reluctance starter/generator results

    Page(s): 1026 - 1034
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    Measured data and simulation results for a two-channel experimental switched-reluctance-motor (SRM)-based aircraft engine starter/generator system are presented. The two channels of the system provide power to two separate and independent loads. The results presented document the performance capability of this system with both channels operating simultaneously. Both measured and predicted system performance are presented and compared. In addition, operating characteristics that are unique to this SRM-based system are described. Of particular interest are the interactions between the two separate channels when one channel experiences a load transient and the other channel does not. The source of channel interactions is described, and measured data is provided. The issue of clearing load faults is also addressed. Design results for adding this capability to the experimental system are described View full abstract»

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  • An evaluation of mitigation techniques for bearing currents, EMI and overvoltages in ASD applications

    Page(s): 1113 - 1122
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    With the increased application of adjustable-speed drives (ASDs) for the efficient speed control of AC motors, there has been a growing number of costly motor drive-related process failures. The popular ASDs consist of a pulsewidth-modulated inverter switching insulated gate bipolar transistors at 2-20 kHz, with rates of voltage rise (dv/dt) of 6000 V/μs. The high dv/dt has adverse effects on the motor insulation due to motor terminal overvoltages (exacerbated by longer cable lengths) and contributes to EMI and damaging bearing and leakage currents caused by common-mode voltages. In response to these problems, a variety of mitigation techniques have emerged. However, often-times the industrial user searching the literature for an immediate solution faces difficulties determining which mitigation technique is best for his/her application. Using laboratory measurements, this paper evaluates and compares various suggested mitigation techniques for bearing currents, EMI and motor terminal overvoltages in terms of their effectiveness and losses and provides practical application assessments for users View full abstract»

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  • Attributing harmonics in private power production

    Page(s): 887 - 892
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    The deregulation of the electric power industry raises new concerns for equitable attribution of harmonics between the private power producers and the rest of the power network. This paper presents a concept for sharing the responsibility for harmonics. The sharing is based solely on measurements during the operation and at the point of connection. The concept is also applicable to other types of steady-state power quality deterioration, namely repetitive RMS fluctuations, waveform distortion and three-phase unbalance View full abstract»

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  • Using a simulation technique for switched-mode high-voltage power supplies performance study

    Page(s): 945 - 952
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    Nuclear experiments need precise and accurate high-voltage power supply for their transducers to maintain their performance. The basic switching power supply unit, which is used for this purpose, consists of a DC-to-DC power converter, an error amplifier and a power amplifier. In this paper, a PC software simulation tool is employed to analyze the performance of two different schemes for the DC-to-DC power converter voltage regulation based on a pulsewidth modulation chip. The behavior of both schemes from power on or load application to steady state is investigated in terms of recovery time, which is important for the transducer's accuracy and, hence, accuracy of measurement. From simulation results, the first scheme is found to recover faster than the second one after load application, and the second scheme suffers from 3% overshoot in the transient response. The first scheme has been constructed practically in a circuit for a 0-2 kV/1 mA supply, and its performance agrees well with simulation results. However, by tuning of the second scheme controller, faster recovery is achieved. Moreover, due to the architecture of the two schemes, the second scheme is more energy efficient 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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