A model predictive control scheme formulation for active rectifiers with LCL filter

In this paper, a step-ahead direct power control (DPC) scheme with reduced sensor count for grid-connected active rectifiers with LCL filter is formulated. Compared to classical model predictive control (MPC) schemes, which implement an L filter, the proposed controller is designed to operate with an LCL filter and thus benefit from higher harmonic attenuation and lower component size and weight. In this work, an expression is derived to allow the prediction of the grid-side current by only measuring the dc-bus voltage, grid voltages, and grid-side line currents. As a result, only 6 sensors are required as opposed to 9 or 12 sensors. An extensive digital computer simulation using Matlab/Simulink is used to demonstrate the validity and performance of the proposed step-ahead DPC scheme. The widely used classical proportional integral (PI)-based power controller is used as a reference to benchmark the steady-state and dynamic performance of the proposed control scheme. The results validate the proposed controller and show its sound steady-state performance consisting of high quality grid-side currents with low Total Harmonic Distortion and unity power factor. In addition, robust and rapid dynamic performance is demonstrated when compared to the classical PI-based controller.