Finite Control Set - Model Predictive Control Applied to a Dual-Converter-Based Rectifier With a Floating DC-Link

This paper discusses the use of the Finite Control Set - Model Predictive Control (FCS-MPC) applied to a dual-converter-based rectifier with a floating dc-link. This configuration has the advantage of avoiding the use of bulky transformers for the case of employing two isolated dc-links, keeping a phase voltage with a high number of steps and low current harmonic distortion. It will be shown that FCS-MPC manages to provide phase currents and the floating dc-link control. Transient- and steady-state simulations were performed to compare the performance of FCS-MPC and a PI-based method. Simulations show that FCS-MPC provides better dynamic response than the considered PI-based method, but has higher current total harmonic distortion (THD) for same average switching frequency, since the PI-based method naturally uses a modulation stage, which reduces the current ripple. Additionally, for the same sampling frequency, FCS-MPC presents much lower switching losses than the PI-based method, but much higher current THD.