Design and Analysis of Integral Terminal Sliding Mode Control of Grid-Connected Inverters

To overcome the adverse effects of external disturbances on grid current quality, this article presents a novel integral terminal sliding mode control (IT-SMC) for a grid-connected three-phase inverter. The integral terminal SMC guarantees finite-time convergence, minimal overshoot, and chattering-free operation. In the mathematical design of the controller, a derivative term is introduced in the capacitor voltages to achieve a better damping effect and prevent overshoot. Additionally, the integral of the grid and inverter current error is incorporated into the sliding surface to achieve precise tracking of the current reference. A 3-kW system is designed using the MATLAB/Simulink tool to analyze the controller’s performance. The grid-current quality and the stability of the controller are analyzed under conditions of grid voltage distortions, impedance variations, and filter resonance frequency. Experimental results confirm that the designed controller ensures nearly zero steady-state error, low grid current harmonics, rapid dynamic response, and system stability under weak grid conditions.