Design of an Energy Storage Converter for Microgrid Applications

The objective of this paper is to propose an energy storage converter (ESC) for microgrid applications. Microgrid integrates distributed generators, load and ESC through various interface power electronic converters to form a small power system. Based on the design of the converter, microgrid can operate normally in grid-connected mode or standalone mode. In grid-connected mode, the grid current controller of ESC is used to regulate demand power for microgrid. When the utility grid fault occurs, the static switch between the utility grid and microgrid is turned-off and the controller of ESC transfers the operation mode from grid-connected mode to standalone mode to supply its power to the load as a stable voltage source. Therefore, the ESC becomes an important role for microgrid stability. In addition, a method of detecting the utility grid fault is proposed to reduce the detection time. The computer simulations and hardware experimental results from a prototype system are presented to verify the validity of the operation principle of the proposed strategy.