Regulated AC to DC converter having a controllable rectifier assembly

Claim 1

In an AC to DC converter for transforming an ideally sinusoidal AC input voltage to a filtered DC output, the converter including a rectifying stage transformer-coupled to the AC input voltage and including a plurality of thyration-like switching elements, and ignition control means for regulating the conductive intervals of the switching elements to maintain the DC output within a predetermined range, the improvement wherein: the converter further comprises, in combination, at least one coil disposed between the output of the coupling transformer and the input of the rectifying stage, and a plurality of diodes individually connected across the switching elements with opposite polarity thereto; and the ignition control means comprises, in combination, means synchronized with the AC input voltage for generating an AC reference current having a phase corresponding to the AC input voltage and an amplitude proportional to the difference between the DC output voltage of the converter and a desired value, and means for adjusting the conductive intervals of the switching elements in accordance with the instantaneous deviation of the actual AC current through the coil from the AC reference current.

Claim 8

A method of maintaining a desired DC output voltage value of an AC to DC converter including a rectifying stage transformer-coupled to a sinusoidal AC voltage and including a plurality of thyratron-like switching elements, a plurality of diodes individually connected across the thyristors with opposite polarity thereto, and a coil connected between the output of the transformer and the input of the rectifying stage, which comprises the steps of: generating a first quantity proportional to the difference between the instantaneous DC output voltage and the desired value; deriving, from the first quantity and the AC input voltage, a sinusoidal AC reference current having a phase synchronized with the AC input voltage and an amplitude proportional to the first quantity; and adjusting the conduction intervals of the switching elements in accordance with the instantaneous deviation of the AC current through the coil and the reference AC current to maintain the amplitude of such deviation within predetermined limits, the adjusting step comprising igniting selected ones of the switching elements in a first pattern to place the DC output voltage in adding relation to the transformer output voltage relative to the coil when such deviation is of one sense, and igniting the selected switching elements in a second pattern to place the DC output voltage in subtracting relation to the transformer output voltage relative to the coil when such deviation is of the opposite sense.

Claim 9

A method of maintaining a desired DC output voltage value of an AC to DC converter including a rectifying stage transformer-coupled to a sinusoidal AC voltage and including a plurality of thyratron-like switching elements, a plurality of diodes individually connected across the thyristors with opposite polarity thereto, and a coil connected between the output of the transformer and the input of the rectifying stage, which comprises the steps of: generating a first quantity proportional to the difference between the instantaneous DC output voltage and the desired value; deriving, from the first quantity and the AC input voltage, a sinusoidal AC reference current having a phase synchronized with the AC input voltage and an amplitude proportional to the first quantity; and adjusting the conduction intervals of the switching elements in accordance with the instantaneous deviation of the AC current through the coil and the reference AC current to maintain the amplitude of such deviation within predetermined limits, the adjusting step comprising igniting selected ones of the switching elements in a first pattern to place the DC output voltage in adding relation to the transformer output voltage relative to the coil when such deviation is of one sense, and igniting the selected switching elements in a second pattern to place the DC output voltage in subtracting relation to the transformer output voltage relative to the coil when such deviation is of the opposite sense.