Fixed Switching Frequency Model Predictive Current Control for Grid-Connected Inverter With Improved Dynamic and Steady State Performance
Durga Malleswara Rao Korada, Mahesh K. Mishra
Abstract
Model Predictive Control (MPC) techniques are widely used in grid connected inverter applications because of their fast dynamics and easy implementation. However, the conventional MPC has inherent drawbacks of computational complexity, average steady-state error, selection of optimum switching vector, variable switching frequency and, laborious weighting factor selection. In this work, a new controller is proposed based on the predictive control for a three-phase two-level grid-connected inverter with inductor-capacitor-inductor filter. The proposed controller performs the fast-tracking of the corresponding reference current with negligible error. The constant frequency achieved with the proposed controller that makes the frequency spectrum better resulting in simple filter design. The current harmonic distortion is well within limits as per the relevant grid codes. The efficacy of the proposed controller is verified with different case studies, including a step change in reference current, grid disturbance, and load change. The direct Lyapunov approach is used to guarantee the stability of the proposed controller. The proposed controller is tested using simulation studies and corroborated with experimental studies.