| 摘要 |
<p>A valve for rapidly switching high voltage at high currents includes several identical modules series-coupled between the high voltage rails. Each module includes a three-terminal semiconductor voltage controlled gate turn-off device ("VCGTO"), an input port for receiving a preferably optically coupled gate drive signal, input circuitry, two power switching ports coupled to the VCGTO device output terminals, and an output circuit coupled across the device output terminals. The input circuitry includes an interface circuit and a drive circuit for driving the VCGTO device in response to the gate drive signal, while the output circuit includes a clamping mechanism and regulated clamp voltage circuit that maintains a safe, regulated maximum differential potential across the VCGTO device. The regulated clamp voltage circuit derives its operating potential from the high voltage switched by the associated GTO device, and provides therefrom a regulated low voltage potential that operates the associated input interface and gate drive circuitry. Because each module is identical, any non-simultaneous switching of the various devices in the series-coupled modules causes only a slight disparity in the amount of energy absorbed by each regulated clamp voltage circuit. Further, each module sees substantially the same differential potential between the module output ports, and operates independently regardless of where in the series-coupled chain the module is located. Dynamic voltage sharing among the various modules is assured, and the valve may be operated at a relatively rapid switching frequency, as no snubber is required.</p> |
