A System Emulator for AC Microgrid Testing

The control algorithms proposed to improve load sharing, stability, and power quality in microgrids need rigorous testing. Real-time emulation is one of the proven approaches to provide realistic testing environments for the development of products and control algorithms. Typically, for microgrid system-level testing, individual component-level (source or load) emulators are employed: hardware test bed clusters. These use multiple converters, increasing control complexity and consuming space. In this article, we propose a flexible microgrid system emulator, based on a single converter for the testing of a complete microgrid, at any node selected by the user. This is unlike the case of emulators proposed in the literature till date, which use a large number of converters to emulate the system dynamics, wherein each converter is used to mimic the behavior of one particular component, such as a single source or a single load. The modeling and control aspects are discussed, and the accuracy of the model developed and the working of the emulator are established through simulations and experiments on a laboratory prototype, respectively, considering the case of a simple two-distributed-generator-based microgrid for various scenarios.