A Low Computing FCS-MPC Based on Voltage Vector Tracking Algorithm With CMVs Suppression and Capacitor Charging Balance Algorithm Without Weight Factors for ANPC 3P-5L Converters

Active neutral-point clamped three-phase five-level (3P-5L) converter system under conventional FCS-MPC algorithm is subjected to high computational burden, large common mode voltages (CMVs), unfixed switching frequency, and cumbersome weight factor design. To tackle above defects, in this article, a low computing FCS-MPC based on voltage vector tracking algorithm with CMVs suppression and capacitor charging balance algorithm without weight factors is proposed for ANPC 3P-5L converters. First, a voltage vector tracking algorithm with CMVs suppression is adopted, which filtrates 64 redundant voltage vectors to reduce CMVs, selects voltage vector by sector boundary conditions to lower computational burden, and enhances vector tracking accuracy with fixed switching frequency. Second, a capacitor charging balance algorithm is proposed to balance flying capacitor voltages (FCVs) and dc capacitor voltages (DCVs) without weight factors, which adjusts operation time of redundant switch states to balance FCVs according to each phase flying capacitor charges, and selects redundant switch states to balance DCVs according to upper and lower capacitor charges. Finally, advantages of proposed MPC are verified in experiment, where the errors of current, FCVs and DCVs are decreased by 1.4 A, 1.2 V and 0.2 V, and current THD, transient time and code execution time are decreased by 2.25%, 20 ms and 151.5 μs respectively.