Model Predictive Control for a Capacitor Voltage Sensorless Grid-Connected Inverter With LCL Filter Based on Kalman Filter

With the increased renewable energy, grid-connected inverters (GCI) with an LCL filter have been widely applied. However, the LCL filter will pose a great challenge to the stability of the system. This paper proposes a model predictive control (MPC) strategy for GCI with LCL filter. Firstly, the grid voltage is regarded as the disturbance quantity, the extended state equation is established, and all state variables are observed based on the Kalman filter (KF). That is, only the grid current needs to be measured to obtain the information of other state variables and apply it to MPC to generate control laws. In addition, the digital delay of the controller is compensated. The effectiveness of the proposed method is verified through simulation.