Positive-sequence virtual-flux control of grid-connected converter during unsymmetrical voltage dips

One of the major problems in direct power-controlled grid-connected voltage source converters is that during dips, converter current increases to compensate for reduced grid voltage. The most common dips are unsymmetrical, and they cause unbalance distortion current. This paper introduces a new, simple but effective algorithm which limits dips. A positive-sequence virtual-flux based control scheme employed this makes balanced sinusoidal unsymmetrical proposed clearly demonstrates performance illustrated through various simulations experimental work. limited magnitude balanced, with low distortion. Implementation will enable stay connected as required by codes.