A New Control Method of Proposed SMC Controller Using the Kalman Filter Estimation for Three‐Phase Asymmetric‐LCL Filtered GCI With Step‐Up Transformer

ABSTRACT In view of the fact that the conventional proportional‐resonant (PR) controller employed in the asymmetric‐LCL (A‐LCL) filter‐based grid‐connected inverter (GCI) faces some challenges in practice, such as complex state space equations, slow dynamic response, and poor robustness, this paper proposes a pulse width modulation (PWM) based improved sliding mode controller (SMC) control method using the Kalman filter estimation for three‐phase GCI with A‐LCL filter. First, a simplified model based on the A‐LCL filter (called the S‐A‐LCL filter model) is proposed, which reduces the system order. Second, the SMC controller is designed based on the S‐A‐LCL model in the control system. Besides, this paper improves the conventional SMC controller on the basis of its design, which has a simple design of its sliding mode surface and a small amount of computation. This proposed SMC controller is called the P_SMC controller. Then, for the P_SMC controller that ought to acquire system state variable information, the Kalman filter estimator is employed to estimate them, reduce the sensor count, save costs, and improve the system's resistance to hardware failures. Finally, a three‐phase/6 kW/380 V/50 Hz A‐LCL filtered GCI with a step‐up transformer experimental setup has been established. It is demonstrated that the control performance of the GCI system with the proposed control method is improved compared to the conventional PR controller employed in an A‐LCL‐based GCI system, and the practicability and excellence of the proposed control method in terms of robust performance, dynamic performance, and disturbance immunity are verified.