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Research and development studies for MHD/coal power flow train components. Final technical report, April 1978-October 1983. [Consolidation equipment].

Author
Bloom, M. H.
Published
United States : [publisher not identified], 1983
Springfield, Va.: National Technical Information Service, [approximately 1983]
Physical Description
microfiche : negative ; 11 x 15 cm

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Summary
Individual control of the current in each electrode segment not only provides the greatest flexibility in the loading of the channel and, hence, permits to achieve the highest efficiency and durability, but also is essential to the prevention of catastrophic failures due to inter-electrode arcs. The pulse width modulated scheme represents a novel approach designed to obtain such a fine tuning with reasonable costs. Instead of striving to maintain the electode current time-invariant despite the fluctuations caused by inhomogeneities in the plasma and by the transport of current in the arc mode, the output of each electrode is purposely chopped at high frequency and controlled by pulse width modulation. Several immediate advantages are envisaged: (1) avoidance of coalescence of multiple arcs into a single one; (2) more uniform current distribution along the width and height of the electrode segment; and (3) quenching of the interelectrode, and in particular interanode arcs. Other advantages, such as (4) avoidance of spatial nonuniformities along the channel; and (5) decreased rates of electric erosion and corrosion may ensue. The conceptual diagram of the pulse width modulated consolidation scheme is shown in Figure 6 and the grouping of electrode segments used in computer simulation is shown in Figure 7. The electrode pairs in one consolidation unit are scanned by the switching arrangement, so that only one electrode pair is conducting current at a time. The a-c output of several consolidation units is phase shifted and connected in series in order to synthesize a fairly sinusoidal wave and thus suppress unwanted harmonics.
Report Numbers
DE85013500; DOE/ET/11056-T8
Other Subject(s)
Collection
NTIS collection.
Note
DOE contract number: AC01-78ET11056
OSTI Identifier 5744174
Research organization: Polytechnic Inst. of New York, Farmingdale (USA).
View MARC record | catkey: 47355364