초록 ▼

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 s

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.

대표청구항 ▼

In a static frequency changer apparatus including positive and negative banks of controllable rectifiers operative between input and output terminals with at least one alternating current power system of lower frequency at said output terminals and with an alternating voltage source of higher freque

In a static frequency changer apparatus including positive and negative banks of controllable rectifiers operative between input and output terminals with at least one alternating current power system of lower frequency at said output terminals and with an alternating voltage source of higher frequency at said input terminals for natural commutation thereof; with said one power system having variable power load conditions; with said voltage source having a selected VA rating and frequency and generating a quadrature input current at said input terminals lagging the input voltage thereof by an amount of lag in relation to said variable load conditions; the combination of: signal means for sensing a condition representative of said quadrature input current to derive a control signal; control means responsive to said control signal for controlling said controllable rectifiers to generate between said positive and negative banks a circulating current of such amplitude as to maintain said quadrature input current lag to a predetermined amount.