A microgrid is an integrated system consisting of interconnected loads and distributed energy sources with a clear entity boundary, operated in either the islanded mode or the grid-connected mode. Among the many challenges in microgrid operation, the frequency and voltage (f-V) control (or, P-Q control) is one of the most challenging tasks. Many previous works in microgrid control use the trial-and-error approach to develop the Proportional-Integral-Derivative (PID) or Proportional-Integral (PI) control gains, which are critical to microgrid stability and control. However, this trial-and-error approach is very time consuming, and the control parameters for the optimal performance at a given operating point may not be effective at other operating points, such as those seen with a change in microgrid operation mode, a new solar Photovoltaic (PV) installation, or a reconfiguration of the network. With all these challenges, the principal investigator plans to investigate a model-free adaptive control (MFAC) for microgrid V-f regulation in islanded mode or P-Q regulation in utility-connected mode, in which the maximum power point and state of charging of the battery will be considered. The features and advantages of the proposed model-free adaptive control include:
The project technology has four distinct features:
The project MFAC approach for microgrids will apply to most, if not all, military microgrids with heterogeneous assets and mission-dependent loads for both islanded mode and grid-connected model. It will be an enabling methodology to smoothly accommodate new load additions and changing load configuration. The plug-and-play characteristic of proposed control will make the integration of the DERs and battery storage and coordinating different type of generators much easier than before. With the planned control approach, the U.S. military could save expenses by switching its bases from diesel backup generators to more efficient microgrids with distributed renewable energy generation and battery. Moreover, the military could protect its critical load, benefiting from the added resilience from the proposed method at a much-reduced cost.