Model Predictive Control of a Grid-Connected Inverter with LCL Filter using Robust Disturbance Observer

This paper proposes a model predictive control (MPC) method using a robust disturbance observer to control the current output of a grid-connected inverter. Firstly, the parameter uncertainties are expressed as possible ranges of resistor, inductor and capacitor values. Secondly, a robust disturbance observer is designed to estimate the lumped disturbance term caused by model uncertainties and the grid voltage disturbance. In addition, the disturbance observer gain, and a weight matrix of the MPC cost function are obtained by applying the Linear matrix inequality (LMI) optimization method. Thirdly, a reference state, which satisfies the control objective of the currents output regulation are derived. Finally, the effectiveness of the proposed MPC method is proven by simulation result.