A universal controller for grid-connected and autonomous operation of three-phase DC/AC converters

This paper presents a controller for three-phase DC/AC converters that is able to operate the converter in grid-connected and stand-alone modes and ensure seamless transition between these modes without reconfiguration of the control structure. The proposed controller provides control over real and reactive powers in grid-connected mode and it performs voltage support in the islanded mode. It integrates the control and the synchronization tasks in a simple and compact structure which not only offers agile responses, it is also well suited for digital implementations.