Digital computation of cycloconverter operation

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ISSN : 0018-9421
Total articles ≅ 1,026

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Maurizio Mazzucchelli, Luciano Puglisi, Giuseppe Sciutto
Digital computation of cycloconverter operation, pp 315-322;

In this paper the extension of the subharmonic method for pulse-width modulation (PWM) systems, in the case in which the ratio between modulating and carrier wave amplitudes can be varied from 0 to ∞, is studied in an analytical way. This method allows us to obtain an inverter output waveform variable continuously from a nearly sinusoidal to a square wave and to increase somewhat the amplitude of the fundamental output wave without a significant worsening of the harmonic content, a feature particularly useful for drives with wide speed variations or which need an optimized use of dc power supply.
Digital computation of cycloconverter operation, pp 406a-406c;

This index covers all technical items - papers, correspondence, reviews, etc. - that appeared in this periodical during the year, and items from previous years that were commented upon or corrected in this year. Departments and other items may also be covered if they have been judged to have archival value. The Author Index contains the primary entry for each item, listed under the first author's name. The primary entry includes the coauthors' names, the title of the paper or other item, and its location, specified by the publication abbreviation, year, month, and inclusive pagination. The Subject Index contains entries describing the item under all appropriate subject headings, plus the first author's name, the publication abbreviation, month, and year, and inclusive pages. Note that the item title is found only under the primary entry in the Author Index.
Lalit M. Patnaik, N. Viswanadham, Isukapalli G. Sarma
Digital computation of cycloconverter operation, pp 353-358;

The specific objective of this paper is to develop multiloop controllers that would achieve asymptotic regulation in the presence of parameter variations and disturbance inputs for a tubular reactor used in ammonia synthesis. The dynamic model considered here has nine state variables, two control inputs, and two outputs. A systematic procedure for pairing the two inputs with the corresponding two outputs is presented. The two multiloop proportional controllers so configured are designed via the parameter plane method. This economic configuration of controllers maintains the temperature profile almost at the optimal value whereas the point controllers fail to do so.
Kuniomi Oguchi, Takashi Osawa
Digital computation of cycloconverter operation, pp 256-259;

A new pulsewidth-modulation method for a three-phase inverter is proposed. The method offers the advantages of a much simpler control logic circuitry and relatively high-quality waveforms of the output voltage. The use of high-power turn-off thyristors allows simplification of the power circuit construction and a reduction in size. The experiments using turn-off thyristors with a rating of 1200 V and 50 A show that both improved waveforms of the output current and high efficiency can be obtained. The details of the control circuits and the driver circuits of the turn-off thyristors are also presented.
Stephen Williamson
Digital computation of cycloconverter operation, pp 266-272;

This paper shows that the voltage and current harmonics introduced by a single-phase triac ac controller can be significantly reduced by shunting the triac with a fixed-value resistance. Theoretical results are given for a purely resistive load and a fixed RL load with a power factor of 0.7, to substantiate this claim.
Barna Szabados, Peter Lindon
Digital computation of cycloconverter operation, pp 252-255;

A pulsewidth modulation (PWM) inverter drive is presented, which uses an original parallel processing technique. The multiplication process of the voltage demand by the instantaneous value of the wave is achieved in time domain using a variable frequency clock. Optimum feedback is used to ensure the accuracy of the analog processing stage, with the result of a rapid and accurate response achieved with a modest component count requiring very little adjustment.
Michael A. Slonim, Isaac Rapoport, Paul P. Biringer
Digital computation of cycloconverter operation, pp 330-335;

A new method has been developed for calculation of the Fourier coefficients of experimentally obtained waveforms. The coefficients are calculated as a function of the values of jumps at the points of waveform discontinuities. Examples are given for some practical waveforms. It has been shown that this method is especially applicable for computer analysis and provides and exact solution as opposed to the currently used approximate computer calculations.
M. H. Rashid
Digital computation of cycloconverter operation, pp 323-330;

This paper uses a computer-based piece-wise linear technique to analyze the dynamic performances of an armature voltage-controlled chopper circuit with a low-pass input filter taking the account of nonlinearities such as the magnetic saturation and the product of variable terms. The performances in the transient conditions which occur in practical situations are predicted by a computer model and are compared with the practical measurements.
Russell J. Niederjohn, Lynn E. Miner, Mark J. Vogel
Digital computation of cycloconverter operation, pp 307-314;

A telephone dial access, user-interactive, information dissemination system is described which incorporates up to eleven tape recorders controlled by an Intel 8085 microprocessor. The system has a dial-in capability permitting the caller to select any one of ten messages he may wish to hear. In addition, all recorded messages are played to the caller as rate-altered or time compressed speech (rate of transmission is changed from that produced by the speaker). The speech rate may be selected independently for each tape recorder, ranging from normal (1.0) to 1.7 times the normal speed. The combination of rate-altered speech and user-interactive capability permits this system to be very efficient for many information dissemination tasks.
Antoine Capel, Marc Clique, Andre J. Fossard
Digital computation of cycloconverter operation, pp 292-307;

High power distribution in continuous or pulsed mode on board application satellites has drastically complicated the design of power conditioning regulators by requiring the reliable operation with brilliant dynamic behavior of complex modular structures to satisfy their powerful loads. Current control modulators satisfy these requirements by the energy control capability. The 50-percent duty ratio instability is analyzed for each power cell configuration and canonical small signal models are given and verified in the case of an MC2 buck regulator. The model validation is verified by application of the least square measurement technique which allows the accurate determination of any transmittance of the closed loop system.
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