Unified Control (UniCon) Strategies for Grid-Connected Inverters

This paper proposes a universal control (UniCon) scheme for grid-connected inverters that allows operation in grid-following and grid-forming modes. The inverter does not need detailed information about the grid and is able to set its own operating point based on local measurements and can operate over a wide range of scenarios. The inverter control strategy can operate with all elements of the grid or microgrids. UniCon allows operation in distinct modes, including dispatch in grid connected mode, and automatic load sharing in islanded or microgrid mode. The use of communications when available is only for slow coordination and system level optimization. Unicon has several distinct elements that have to all function in an integrated manner to realize desired overall system level behavior. It is believed that such a universal control strategy is needed for inverters for transition from today’s synchronous generator dominated grid to an inverter-based resources (IBR) dominated grid.