Equivalent Input Disturbance Estimation Combined with Observer Kalman Filter Identification for Three-Phase Four-Leg Inverters in an AC Battery Application

This paper presents equivalent input disturbance (EID) estimation-based observer Kalman filter identification (OKID) for a three-phase four-leg (3P4L) converter in an AC battery application. Firstly, this paper constructs an equivalent linear time-invariant discrete-time model and its state estimator via the proposed OKID approach for the 3P4L converter in the standalone mode. Secondly, an adaptive disturbance estimation scheme is provided to establish an EID estimator for the 3P4L converter with unknown parameters. Finally, both simulation and experimental prototypes of the 3P4L converter in the AC Battery application are carried out to verify the proposed control method. The quality of the output voltage with the nonlinear load, mismatched model, and fast dynamic response is evaluated, which proves the advantages of the proposed method compared to the traditional PI controller.