Vector inversion generator: Difference between revisions

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==Construction==

Discrete component VIGs (pictured) consist of a stack of well-coupled common mode chokes interconnected with a stack of capacitors. The inductors present a high inductance to currents that are in-phase in the two windings, and a far lower inductance when the winding currents are flowing in opposite directions. The capacitors are charged with alternating polarity and when the switch (usually a triggered or free running spark gap in practice) is closed the voltage accrossacross every second capacitor rapidly inverts as a half cycle of oscillation at a frequency set by the capacitance resonating with the differnetialdifferential mode inductance of the chokes. At the same time the other capacitors discharge very slowly due to not having a differential current flowing to cancel the reactance.

So after a half period, all the capacitors are in series and the voltages add.

This arrangement has a conceptual equivalence to the distributed component spiral VIG, with the alternating capacitors representinrepresenting the two transmission lines of alternating polarity and the spiral turns representing successive stacked stages.

Discrete components allow large lumped capacitors to be used thus storing much more energy, but have difficualtydifficulty replicating the high voltage multiplication ratios and extremely short rise times of spiral transmission line types.

A spiral VIG consists of four alternating conductor-insulator-conductor-insulator sheets, wound into a cylinder, forming a [[capacitor]] also acting as a single-ended [[transmission line]], connected to a [[spark gap]] switch. The capacitor is charged from a power source, e.g. the EDFEG, then the spark gap fires after its [[breakdown voltage]] is reached. The [[electromagnetic wave]] created by the [[electric spark]] discharge travels along the transmission line, converting [[electrostatic field]] to [[electromagnetic field]], then after reflecting from the open end converts back to electrostatic field. A pulse of output amplitude 2nU (where n is the number of turns of the capacitor and U is the initial voltage it was charged to) and a rise time equal to twice the [[electrical length (transmission medium)|electrical length]] of the transmission line.<ref>http://scholarsmine.mst.edu/post_prints/pdf/physics_09007dcc80588630.pdf</ref><ref>http://www.boliven.com/patent/US7151330/drawings</ref><ref>http://shadaly.com/vector_inversion_generator_4507567.html</ref> The device acts as a distributed [[pulse forming network]].