The Passivity-Based Control with Kalman Filter Observer of Three-phase Grid Connected Converter

This paper proposes a method to enhance inverter control performance while minimising sensor usage and hardware expenses by substituting actual electrical values with estimated values obtained from a Kalman filter observer in the passive control strategy of three-phase grid-connected inverters. This article analyses the working principle and mathematical model of the inverter, followed by the design of a passive controller and a Kalman filter observer based on this analysis. The theoretical analysis presented in this paper was validated through the Simulink simulation platform. The results indicate that the introduction of the Kalman filter observer in the proposed passive controller has a minor effect on the system's steady-state and transient performance; however, the controller maintains satisfactory static and transient performance. The introduction of an observer enhances the system's robustness against severe external disturbances, including system impedance, three-phase voltage imbalance, and voltage harmonics, while also reducing hardware costs significantly.