Cgee Alsthom

Ogee Alsthom

Michel Cailloux

The invention comes within the field of static converters. A static converter which comprises two Graetz rectifier bridges connected together at their DC terminals by first and second connections. One of the bridges is connected to the AC mains by means of a transformer and the other is connected to a variable speed synchronous machine. A third connection links the neutral conductor of the stator winding of the synchronous machine to the neutral conductor of the secondary winding of the transformer. Control means of the rectifier connected to the mains provide independent control for the upper half-bridge and the lower half-bridge of the rectifier.

Static AC/AC thyristor converter for a self-driven synchronous motor

The invention comes within the field thyristor bridge control. A device for controlling a Graetz rectifier bridge for driving a synchronous machine which operates at variable speed, it being connected to this machine by its AC terminals and its voltage at the terminals being substantially proportional to its frequency, characterized in that the firing pulses of each thyristor of the Graetz rectifier bridge come from the comparison of a control signal U.sub.c chosen as a function of the required firing angle .alpha. of the thyristor to be fired, with a sinusoidal phase reference curve whose amplitude is made independent from the operation frequency of the Graetz rectifier bridge. The invention applies in particular to the driving of synchronous rotating machines which operate at variable speed.

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Belfort, France

Michel Cailloux