A switch mode power supply can do a whole lot more than act as a rectifier. "Switch mode" refers to the turning on and off of numerous silicon switches usually

A switch mode power supply can do a whole lot more than act as a rectifier. "Switch mode" refers to the turning on and off of numerous silicon switches usually connected to some kind of LC energy storage/filter, and this is the basis of modern rectifiers, inverters, step-up and step-down converters, etc. It is in fact possible to use a switching circuit to convert an arbitrary ac voltage/frequency to another arbitrary ac voltage/frequency directly without a DC link intermediary. This is called a "matrix converter." http://en.wikipedia.org/wiki/AC/AC_converter http://en.wikipedia.org/wiki/AC/AC_converter So it should theoretically be possible to take say 200VAC at 400 Hz and convert this to 120VAC 60Hz. In fact this would probably be more compact/less expensive than the usual inverters mentioned in this article, since these are usually meant to be powered by a low voltage DC source and thus have to deal with taking a low voltage and very high current and first stepping this up to several hundred volts, then modulate it into an AC sine wave. A matrix converter (or even AC-DC-AC converter) would have no such requirement if it were powered from the already high voltage aircraft power bus. At this point I think it's a matter of the technology catching up, since this is a highly specialized application that has just recently become an opportunity for innovation. EDIT: Also - 240W per person? This seems outrageously high as a baseline load. I would estimate more like 50-100W per person on average, with 300W peak (like when the power supply is first plugged in.) The peak loads would not all happen at once unless everyone decides to plug in and turn on their computers at once, in which case the power limiting would kick in...