Patent ID: 8649195

Claim:
A method of controlling a modular three-phase converter that comprises three interleaved, parallel connected Voltage Source Converters (VSCs), comprising: obtaining a sample of a revolving reference voltage vector that defines a reference voltage magnitude and angle of the revolving reference voltage vector; identifying one of a plurality of quasi-optimal zones in a space vector plane that corresponds to both the reference voltage magnitude and the angle of the revolving reference voltage vector, wherein the plurality of quasi-optimal zones comprises a first quasi-optimal zone defined for 0°<α<30° and 0<V REF <0.3 having a first corresponding optimal Space Vector Pulse Width Modulation (SVM) switching sequence, a second quasi-optimal zone defined for 0°<α<30° and 0.3<V REF <0.6 having a second corresponding optimal SVM switching sequence, a third quasi-optimal zone defined for 0°<α<30° and V REF >0.6 having a third corresponding optimal SVM switching sequence, a fourth quasi-optimal zone defined for 30°<α<60° and 0<V REF <0.3 having a fourth corresponding optimal SVM switching sequence, a fifth quasi-optimal zone defined for 30°<α<60° and 0.3<V REF <0.6 having a fifth corresponding optimal SVM switching sequence, and a sixth quasi-optimal zone defined for 30°<α<60° and V REF >0.6 having a sixth corresponding optimal SVM switching sequence, where V REF is the reference voltage magnitude and α is the angle of the revolving reference voltage vector; and applying the corresponding optimal SVM switching sequence for the one of the plurality of quasi-optimal zones to the modular three-phase converter.