Control approaches of current-source rectifier: Predictive control versus PWM-based linear control

Abstract

Nowadays, finite control set model predictive control (FCS-MPC) is very popular because it is effective, simple and suitable for control of various types of power converters. It is also a flexible tool because it evaluates an arbitrary cost function which directly influences converter behavior according to particular demand (i.e. shape of the current, switching frequency, switching losses etc.). However, some drawbacks of FCS-MPC, such as variable switching frequency or steady-state error, have also been reported. The limitation is also in the fact that efficient calculation is available only for very short prediction horizon (mostly one-step-ahead), otherwise the computational demand increases significantly. In this paper, we present a comparison and evaluation of the FCS-MPC improved with an approximation by an LQR (which enables an extension to long prediction horizons) and a widely used control with PI controller with space vector modulation (SVM). The comparison is performed on current-source rectifier (CSR) in terms of output current tracking quality, input current THD and switching frequency. Final results will be introduced by simulation study in MATLAB/Plecs and laboratory experiments.