A Robust and Structurally Simple Controller for Inverter Applications

This paper presents a robust servomechanism controller for operation of converter-based distributed energy resource (DER) units. The aim is to maintain the terminal voltage at a desired reference value and to ensure strong robustness versus uncertainties and load changes. The control design is based on the theories of robust servomechanism problem (RSP) and the linear quadratic tracker (LQT) and has a multi-input multi-output (MIMO) approach. Despite its simple structure, the proposed controller is characterized by fast transient response, low coupling among output channels and zero steady-state error. The performance of the proposed controller is evaluated through the extensive computer simulations using electromagnetic transient program (EMTP).