Individual-phase control of 3-phase 4-wire voltage-source converter

An innovative method of operating 3-phase, 4-wire voltage-source converters, based on decoupled P-Q control of individual phases, is presented. Individual-phase control has six independent degrees of control freedom to deal with both symmetrical and asymmetrical operating conditions. Experimental tests on a laboratory distribution static synchronous compensator (D-STATCOM) show that individual-phase control can simultaneously (i) support the voltages of unbalanced 3-phase loads against droop; (ii) equalise the complex powers at source-side of the transmission line; (iii) balance the voltage magnitudes and (iv) balance the angles of `ac´ voltages at the point-of-common-coupling.