Polynomial design method for a current controller applied to a single-phase grid-connected VSI with LCL filter

A design method based on the Diophan-tine equation is used for determining current controller parameters. The two main control objectives are: to put the closed loop poles in predefined locations;and to track the reference signal. The reference signal tracking problem is solved using the internal model principle. It introduces the reference generating polynomial into the controller design problem. The controller gives zero steady state error at specific frequency points and also satisfies other performance requirements using the sufficient free parameters. It also shown that the PRES controller is a particular case of the proposed controller. The design method is applied to the PRES controller for a single-phase grid-connected voltage source inverter using a LCL filter. Simulation examples and robustness tests are provided to illustrate the feasibility of the proposed approach. Hardware-in-the-loop simulations using the OPAL-RT real-time simulator with the dSPACE controller are also provided.