Finite Control Set - Modulated Model Predictive Control for a 5L-Flying Capacitor Multilevel Converter

In this paper, a constant switching frequency Finite Control Set Modulated Model Predictive Control (FCS-M2PC) is proposed for a single phase 5-level flying capacitor multilevel converter with an output LC filter operating as an Uninterruptible Power Supply (UPS). In the proposed method, first Finite Control Set Model Predictive Control (FCS-MPC) is used to generate the reference voltage by inspecting all the possible converter output voltages taking into account the control delay. Then, the generated reference is applied to a modulator operating with Phase Shifted Pulse Width Modulation (PSPWM) scheme. The application to the modulator ensures a constant output switching frequency and proper voltage balancing of the flying capacitors (FCs'). The proposed method is easy to implement and provides a fast dynamic response, robustness to the load change, constant switching frequency, and decreases the computational burden of traditional FCS-MPC. Finally, the performance of the FCS-M2PC is verified by implementing different scenarios on a experimental setup and the results are presented.