Voltage sensorless predictive current control with interfacing parameter estimation for grid connected converter operation

This paper proposes a stationary frame based predictive current controller for LCL coupled grid interfaced systems. Analytical expressions for the sources of error in the predictive current control, especially for low switching frequency operation, are derived. The grid voltage estimation expressions for sensorless operation are derived to enhance system reliability and performance, therein decreasing the number of measurement sensors. The on line adaptive control algorithm guarantees robustness of the proposed system. The stability margin for the predictive current gain is also presented. The stability and robustness of the predictive current control is mainly affected by parameter variation. A normalized least mean square adaptive method is used to estimate the necessary system interfacing parameters. The proposed control solution provides high quality current injection into the grid, whence, high power quality. Finally, simulated and practical results verify the derived expressions and the performance of the proposed control system.