5. Multi-objective and Adaptive Distributed Control of AC Microgrids

This chapter discusses the advanced methods for distributed control of AC microgrids. First, a two-layer control framework that implements the secondary control for an islanded microgrid containing both VCVSIs and CCVSIs is discussed. The first control layer deals with the voltage and frequency control of VCVSIs. The second control layer objectives are to control the active and reactive powers of CCVSIs. Each control layer is implemented through the distributed control of multi-agent systems. Then, a distributed and adaptive secondary voltage control method is discussed. The proposed controller compensates for the nonlinear and uncertain dynamics of DGs and, hence, obviates the control design challenges caused by the nonlinear dynamics of DGs. The controller is fully independent of the DG parameters. Therefore, the controller can be deployed on any DG regardless of the DG parameters and the connector specifications, and its performance does not deteriorate by the change in DG parameters (e.g., due to aging and thermal effects). The discussed controller appropriately responds to the changes in the system operating condition, without any manual intervention, and adjusts its control parameters in real time.