A pulse-amplitude-synthesis-and-control (PASC) consolidation/inversion system for Faraday connected MHD generators

The problem of consolidating and inverting a number of DC sources is common in interconnecting arrays of batteries, fuel cells, solar cells, multi-electrode pair magnetohydrodynamic (MHD) generators, etc. This paper describes a general technique for performing such power processing when applied to the specific example of consolidation followed by three phase inversion, of a number of DC sources produced by a Faraday connected MHD generator. The method employs banks of pulse transformers, one bank per phase, in which the secondaries of each transformer have been connected in series and two opposite polarity primaries are pulsed from the DC sources. The sequence in which the primaries are pulsed determines the shape of the resulting AC waveform. The process, or method, is called PASC (pulse amplitude-synthesis-and-control), and utilizes a switching array to connect/disconnect one or more DC sources in an overlapped fashion under computer actuation along with error output-signal feedback, to generate the control necessary to match the desired waveform as specified in the computer. Although the principle benefit of this system is consolidation of diverse and isolated DC sources, it is shown that quantized sinusoids can be synthesized with low harmonic content precluding the need for expensive and inefficient filtering such as is required by conventional static inverters. A prototype single phase, 24 kVA, eight transformer system has been built and extensively tested. This system is described and representative experimental results are shown