摘要 |
<p>A variable phase-shifting transformer network including at least one pair of multi-phase transformers, wherein the network transformation ratio and phase shift is step wise adjustable as a result of the provision of plural auxiliary windings located on the core of a preselected secondary winding, each auxiliary winding having plural taps, which are not initially interconnected. Each transformer phase includes an AC semiconductor switch connected across selected tappings of the respective auxiliary windings via selected watt-less isolating switches. The voltage vector appearing across a selected secondary winding is varied by connecting an non-ignited semiconductor switch, via the isolating switches associated therewith, to desired tappings of the respective auxiliary windings while the rectifier is non-current conducting. Thereupon this AC semiconductor switch is ignited and ignition pulses are removed from the previously conducting semiconductor switch.</p> |