Structured Controller Parameter Tuning for Power Systems

Abstract: Reliable and secure operation of power systems becomes increasingly challenging as the share of volatile generation rises, leading to largely changing dynamics. Typically, the architecture and structure of controllers in power systems, such as voltage controllers of power generators, are fixed during the design and buildup of the network. As replacing existing controllers is often undesired and challenging, setpoint adjustments, as well as tuning of the controller parameters, are possibilities to counteract large disturbances and changing dynamics. We present an approach for fast and computationally efficient adaptation of parameters of structured controllers based on H-infinity optimization, also referred to as structured H-infinity controller synthesis, tailored towards power systems. Conditions are established that guarantee that the approach leads to stability.The results are verified in a testbed microgrid consisting of six inverters and a load bank, as well as simulation studies. The proposed method improves the system robustness, as well as the time-response to step disturbances and allows structured controller tuning even for large networks.