Naturally commutated cycloconverter with controlled input displacement power factor

TLDR: In this paper, a cycloconverter having at the input a source of higher frequency than at its output is used as a static reactive power generator to correct displacement angle in an alternating current power system when coupled to a power system at the output.

Abstract: A naturally commutated cycloconverter having at the input a source of higher frequency than at its output is used as a static reactive power generator to correct displacement angle in an alternating current power system when coupled thereto at the output. Reactive power correction is obtained with such "high frequency link" by automatically controlling the output voltage of the cycloconverter so as to deviate by a required amount from the AC power system voltage. At the same time, a circulating current is established between the positive and negative banks of thyristors of the cycloconverter of such a magnitude as to compensate for the variations of the lagging quadrature component of the input current of the cycloconverter caused by output current variations, thereby permitting optimization of the high frequency link. The concept of generating controllable reactive power with a naturally commutated cycloconverter is used (1) with one cycloconverter as a controllable source of reactive power coupled to a power system; (2) with two cycloconverters tying a power system with a load, or two power systems together. In either instance, the output voltage of the cycloconverter is controlled for automatic compensation in the line power factor, and concurrently a circulating current is established in the single or in the two cycloconverters for automatic correction against variations in the lagging current at the cycloconverter input when the load conditions at the output thereof vary.