Patent ID: 11374407

Abstract:
A method for correct operation of the current-angle-based phase-selection method (PSM) is based on a proper dual current controller (DCC) for inverter interfaced sources during unbalanced fault conditions. The fault type is determined in the inverter using voltage-angle-based PSM. Accordingly, fault-type zones' bisectors of the current-angle-based are determined. Consequently, an initial negative-sequence current angle reference is determined to force the relative angle between the negative- and zero-sequence currents in the center of its correct fault-type zone. The initial positive-sequence current angle is determined according to reactive current requirements by grid codes. These initial angles are updated for accurate operation of the PSM and appropriate reactive current injection. Negative- and positive-sequence current references are determined in the stationary frame to comply with the reference angles and inverter's thermal limits. These references are regulated by a proportional-resonance controller.