Controller Area Network Assisted Grid Synchronization of a Microgrid With Renewable Energy Sources and Storage

Microgrids are emerging as an important constituent of large-scale smart grids. They are equipped with the controls necessary for managing the operation in islanded or grid connected mode and serve the loads with clean, reliable, and uninterruptible power. Microgrid must be equipped with a robust grid synchronization (GS) algorithm so as to allow a smooth transfer from islanded mode to grid tied mode. This gets even more critical when the availability of the power grid is irregular or the power grid is weak. This paper proposes a simple yet highly reliable GS technique based on controller area network (CAN) communication. The grid synchronizer block senses the three phase grid voltages, derives the phase angle (theta) using synchronously rotating reference frame-based phase lock loop, and transmits this information on the CAN network to all microsources (MS). The local controller associated with each MS receives the data with small but known and definite time latencies. This allows each MS to energize simultaneously in synchronization with the grid, facilitating easy GS of all the MS, minimizing the time required for GS of the complete microgrid. All the analytical, simulation, and hardware results related to this paper are presented.