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Energy Conversion, IEEE Transactions on

Issue 1 • Date Mar 1993

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Displaying Results 1 - 20 of 20
  • Laboratory implementation of a neural network trajectory controller for a DC motor

    Page(s): 107 - 113
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    The laboratory implementation of a neural network controller for high performance DC drives is described. The objective is to control the rotor speed and/or position to follow an arbitrarily selected trajectory at all times. The control strategy is based on indirect model reference adaptive control (MRAC). The motor characteristics are explicitly identified through a multilayer perceptron type neural network. The output of the trained neural network is used to drive the motor in order to achieve a desired time trajectory of the controlled variable. The neural network controller is assembled in a commercially available PC-based real-time control system shell, using software subroutines. An H-bridge, DC/DC voltage converter is interfaced with the computer to generate the specified terminal voltage sequences for driving the motor. All software and hardware components are off the shelf. The versatility of the motor/controller arrangement is displayed through real-time plots of the controlled states View full abstract»

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  • Operation principle and applications of multiterminal superconductive magnetic energy storage systems

    Page(s): 54 - 62
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    The basic operation principle of a multiterminal superconductive magnetic energy storage (MSMES) system is introduced. The motivation for developing the MSMES systems is to combine and maximize the flexibility benefits provided by energy storage and the controllability benefits provided by power electronic systems. A MSMES system can be used simultaneously as an energy storage device and a power flow control device. This attribute enables MSMES systems to perform some unique functions in electric power systems. Potential applications of MSMES systems and their impact on solving the problems faced by power systems today are discussed View full abstract»

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  • Tests with a microcomputer based adaptive synchronous machine stabilizer on a 400 MW thermal unit

    Page(s): 6 - 12
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    Field tests have been conducted on a microcomputer-based self-tuning adaptive synchronous machine stabilizer. The adaptive control algorithm tracks the system operating conditions using a least squares identification technique with variable forgetting factor and the control is calculated by a self-searching pole-shift method. An outline of the control algorithm and the results of field tests on a 400 MW thermal generating unit are described View full abstract»

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  • Linear current mode controller for battery test applications

    Page(s): 20 - 25
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (348 KB)  

    This study describes the design and implementation of a current sink and source controller for battery evaluation. Two types of controllers were designed, one for low rates of current and the other for high rates of current. The operation of th controllers is implemented using control algorithms to perform both current and voltage modes of operation. Controller performance is analyzed by comparing requested values with measured values to insure proper current output from the controllers View full abstract»

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  • Advanced techniques for noise source identification on a large generator unit

    Page(s): 114 - 122
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    Power station acoustic noise assessment, which has experienced increased environmental awareness and subsequently more stringent legislation for a number of years, has received an added stimulus due to the recent advent of powerful measurement and analysis techniques, including sound intensity and coherence. These experimental techniques are explained, and results, for a generator unit, illustrate their value in providing a unique, correlated insight into noise problems. This insight includes noise quantification, full explanation of site sound pressure level in terms of the various influences, and major noise source identification. These techniques are widely applicable and an invaluable aid to any industrial noise problem View full abstract»

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  • An artificial neural network based adaptive power system stabilizer

    Page(s): 71 - 77
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    An artificial neural network (ANN)-based power system stabilizer (PSS) and its application to power systems are presented. The ANN-based PSS combines the advantages of self-optimizing pole shifting adaptive control strategy and the quick response of ANN to introduce a new generation PSS. A popular type of ANN, the multilayer perceptron with error backpropagation training method, is used in this PSS. The ANN was trained by the training data group generated by the adaptive power system stabilizer (APSS). During the training, the ANN was required to memorize and simulate the control strategy of APSS until the differences were within the specified criteria. Results show that the proposed ANN-based PSS can provide good damping of the power system over a wide operating range and significantly improve the dynamic performance of the system View full abstract»

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  • CO2 recovery in molten carbonate fuel cell system by pressure swing adsorption

    Page(s): 26 - 32
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    Carbon dioxide (CO2) recycle configuration using pressure swing adsorption (PSA) is examined in the indirect internal reforming molten carbonate fuel cell (IIR-MCFC) system. It is shown that the CO2 PSA makes the system efficiency higher than in an ordinary combustion process. A test plant was fabricated in order to evaluate the PSA performance in the IIR-MCFC system. The experimental results with respect to CO2 recovery ratio, purity, and pressure fluctuations in both electrode chambers are acceptable View full abstract»

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  • Turbine generator laboratory model tests to damp torsional oscillations with supplementary signals

    Page(s): 85 - 91
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    The improvement of generator stability by the use of supplementary signals into the voltage regulator and governor loops using discrete-time linear optimal control theory has been studied with particular emphasis on providing better damping for torsional oscillations. A multi-inertia laboratory model equipped with data acquisition and control computers was constructed to model the shaft dynamics of a 660 MW Drax turbine-generator. It is shown that the shaft torsional phenomena can be adequately simulated on a micro-synchronous-generator at least as far as the dominant shaft torsional modes of vibration are concerned. The practical implementation of multi-mode linear quadratic Gaussian (LQG) controllers has been shown to enhance system stability and provide better damping to the lower frequency torsional modes, which are those most susceptible to excitation View full abstract»

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  • Application of simultaneous active and reactive power modulation of superconducting magnetic energy storage unit to damp turbine-generator subsynchronous oscillations

    Page(s): 63 - 70
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    An active and reactive power (P-Q) simultaneous control scheme, which is based on a superconducting magnetic energy storage (SMES) unit, is designed to damp out the subsynchronous resonant (SSR) oscillations of a turbine-generator unit. In order to suppress unstable torsional mode oscillations, a proportional-integral-derivative (PID) controller is used to modulate the active and reactive power input/output of the SMES unit according to speed deviation of the generator shaft. The gains of the proposed PID controller are determined by pole assignment approach based on modal control theory. Eigenvalue analysis of the studied system shows that the PID controller is quite effective over a wide range of operating conditions. Dynamic simulations using the nonlinear system model are also performed to demonstrate the damping effect of the proposed control scheme under disturbance conditions View full abstract»

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  • Adaptive control of speed and equivalence ratio dynamics of a diesel driven power-plant

    Page(s): 13 - 19
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    A method of modeling, involving approximation of dead-times, is presented for diesel driven power prime-movers. The resulting predictive adaptive control scheme is compared to a conventional PI scheme on the basis of common disturbances encountered by a practical prime-mover. It is found that the adaptive scheme achieves significant improvement despite the nonlinearities introduced by turbocharger operation. It is observed in general that adaptive schemes, such as the one described, affect the prime-mover dynamics in essentially two ways. First, the engine fuel-flow response is improved by better control of the actuator. Secondly, by indirectly controlling the exhaust energy of the plant, the turbocharger air-dynamics is made faster, leading to better dynamic fuel/air ratio. The overall effect is good response of the prime-mover speed notwithstanding the fact that the diesel prime-mover is a low inertia structure and that the system parameters suffer from various nonlinear variations View full abstract»

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  • A review of manufacturers recommendations for the grounding of distributed control system in generating stations

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    This progress report was prepared by the IEEE Working Group on Std 1050, `Guide for Instrumentation and Control Equipment Grounding in Generating Stations'. It summarizes a review of the grounding recommendations made by the manufacturers of 11 distributed control systems which are presently being applied in generating stations. The diversity of grounding recommendations shown by this review is discussed along with a necessary course of action View full abstract»

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  • Multivariable robust control of a power plant deaerator

    Page(s): 123 - 129
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    The design of a robust controller for the deaerator of the Experimental Breeder Reactor-II (EBR-II) that uses the linear quadratic Gaussian with loop transfer recovery (LQG/LTR) procedure is described. At present, classical proportional-integral (PI) controllers are used to control the deaerator. When the operating condition changes, the system is disturbed, or a fault occurs, and the PI controllers may fail to maintain the desired performance. A robust controller that can accommodate system faults and obtain a reasonable behavior for a wide range of model uncertainty was designed. The controller provides the desired performance despite a considerable change in the operating condition, accommodates some of the failures that can occur, and provides the choice of penalizing one variable over another. The design is tested for robustness by varying the system operating conditions and simulating a steam valve failure. The set of nonlinear simulations using the modular modeling system and the advanced continuous simulation language is included View full abstract»

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  • Approximate analysis of steady-state heat conduction in an induction motor

    Page(s): 78 - 84
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    The problem of two-dimensional steady-state heat flow in the stator of an induction motor is solved using finite element formulation and using arch shaped elements in the θ plane of the cylindrical coordinate system. The shape functions and exact solution matrices are derived algebraically for utmost economy in computation. The temperature distribution has been determined considering convection from the stator frame and the cylindrical air-gap surface. The temperatures obtained by this two-dimensional approximation are compared with the actual temperatures obtained by three-dimensional analysis View full abstract»

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  • Thyristor-controlled voltage regulators for critical induction motor loads during voltage disturbances

    Page(s): 100 - 106
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB)  

    The transient stability of a critical induction machine load group during momentary as well as continuing voltage sags can be enhanced by using a fast-response voltage regulator in the form of a static VAr compensator (SVC) or a thyristor controlled tap changer (CTC). A procedure is presented for determining the minimum SVC rating or CTC off-nominal turn ratio including control of the SVC admittances or CTC taps to meet dynamic and steady-state specifications. The limitations of their effectiveness to preserve operation continuity are also shown View full abstract»

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  • Analysis and average-value modeling of line-commutated converter-synchronous machine systems

    Page(s): 92 - 99
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB)  

    Analytical relationships are established which can be used to predict the steady-state characteristics of line-commutated AC-DC-converter-synchronous machine systems. In particular, basic relationships are established in which the average DC voltage and the average electromagnetic torque are related to the converter firing delay angle. It is shown that these average-value relationships predict the steady-state performance with significantly higher accuracy than the classical converter average-value equations in which the d-axis subtransient reactance is used as the commutating reactance View full abstract»

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  • Starting characteristics of direct current motors powered by solar cells

    Page(s): 47 - 53
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    The authors deal with the calculation of the starting to rated current ratio and starting to rated torque ratio of the permanent magnet, separately, series and shunt excited motors when powered by solar cells for the two cases where the system includes a maximum-power-point-tracker (MPPT), and without an MPPT. Comparing these two cases, one gets a torque magnification of about three for the permanent magnet motor and about seven for other motor types at rated design insolation. The calculation of the torques may assist the photovoltaic system designer to determine the advantage of including an MPPT in the system as far as the starting characteristics of the DC motors are concerned View full abstract»

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  • Commercial grade item (CGI) dedication of generators for nuclear safety related applications

    Page(s): 138 - 144
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    The general guidelines for the commercial grade item (CGI) acceptance and dedication are provided in US Nuclear Regulatory Commission (NRC) Generic Letters and Electric Power Research Institute (EPRI) Report NP-5652, `Guidelines for the Utilization of Commercial Grade Items in Nuclear Safety Related Applications'. These generic guidelines are applied to the procurement, acceptance, and dedication of a commercial grade generator for use as a standby generator. The author identifies the critical characteristics of the generator, which, once verified, will provide reasonable assurance that the generator will perform its intended safety function. The author also delineates the method of verification of the critical characteristics through tests and provides acceptance criteria for the test results. The methodology presented may be used for reliable, cost-effective procurement and dedication of commercial grade standby generators View full abstract»

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  • A step towards improvements in the characteristics of self excited induction generator

    Page(s): 40 - 46
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    Improvements of voltage regulation characteristics of self-excited induction generators (SEIGs) are investigated. Typical results of the sensitivity studies performed are presented and conclusions are drawn to suggest guidelines for design of such generators View full abstract»

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  • Design, performance, and cost characteristics of high temperature superconducting magnetic energy storage

    Page(s): 33 - 39
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    A conceptual design for superconducting magnetic energy storage (SMES) using oxide superconductors with higher critical temperature than metallic superconductors has been analyzed for design features, refrigeration requirements, and estimated costs of major components. The study covered the energy storage range from 2 to 200 MWh at power levels from 4 to 400 MW. A SMES that uses high temperature superconductors (HTS) and operates at high magnetic field (e.g. 10 T), can be more compact than a comparable, conventional low-temperature device at lower field. The refrigeration power required for a higher temperature unit (20 to 77 K) will be less by 60% to 90%. The improvement in energy efficiency is significant for small units, but less important for large ones. The material cost for HTS units is dominated by the cost of superconductor, so that the total cost of an HTS system will be comparable to a low temperature system only if the superconductor price in $/ampere-meter is made comparable by increasing current density or decreasing wire cost View full abstract»

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  • A bibliography of technical papers relating expert systems to nuclear power plants

    Page(s): 130 - 137
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    Over the period of 1985 through 1990, numerous papers were published on the subject of artificial intelligence (AI) and expert systems (ES) applications at nuclear power plants. A selection of these papers is given, arranged in the following categories: general descriptions of AI/ES techniques, specific AI/ES applications, knowledge-base development and modeling techniques, maintenance and diagnostics, operations and training support, procedural assistance and emergency response, risk assessment and reliability, and design tools View full abstract»

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Aims & Scope

The IEEE Transactions on Energy Conversion includes in its venue the research, development, design, application, construction, installation, operation, analysis and control of electric power generating and energy storage equipment (along with conventional, cogeneration, nuclear, distributed or renewable sources, central station and grid connection). The scope also includes electromechanical energy conversion, electric machinery, devices, systems and facilities for the safe, reliable, and economic generation and utilization of electrical energy for general industrial, commercial, public, and domestic consumption of electrical energy.

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Meet Our Editors

Editor-in-Chief
Juri Jatskevich
University of British Columbia