Control techniques for operation of roof-top solar photovoltaics based microgrid in islanded mode

This paper presents the control techniques for the operation of roof-top solar photovoltaics based single-phase ac microgrid in islanded mode. The proposed microgrid consists of four roof-top photovoltaics on various buildings, battery energy storage system in each building, and loads. In each building, the roof-top photovoltaic system is connected to the single-phase ac loads and proposed single-phase ac microgrid through the two-stage converter, which consists of dc-dc boost converter and bidirectional single-phase voltage source converter. A bidirectional dc-dc converter is used to connect the battery energy storage system to the photovoltaic system. The control technique of the bidirectional single-phase voltage source converter, using the feed-forward and feed-back control signals, has been suggested into a rotating d-q synchronous reference frame, with the dual controllers, for controlling the power mismatch and rated sinusoidal ac voltage of the microgrid. The control technique of the bidirectional dc-dc converter, used for the battery energy storage system, is implemented with two voltage controllers and one current controller for managing of the power mismatch in the proposed microgrid system. In this work, the power control algorithms have also been developed, which are aimed to manage the power balance in the single roof-top PV based building as well as in the proposed microgrid, under islanded mode, for various operating scenarios including fault condition.