An Improved Line Voltage Coordinate-Based FCS-MPC with Fixed Switching Frequency and Low CMV for Five-Level ANPC Converter

This paper proposes an improved finite control set model predictive control (FCS-MPC) algorithm based on line voltage coordinate with fixed switching frequency (FSF) for the five-level ANPC (5L-ANPC) converter. First, compared to the conventional FCS-MPC for 5L-ANPC converter, the improved FCS-MPC employs the line voltage coordinate to avoid complicated boundary condition calculations of the reference voltage vector. Second, the improved FCS-MPC confines common-mode voltage (CMV) fluctuations to one-sixth of the dc-link voltage by selecting 85 voltage vectors. Third, a capacitor voltage balancing algorithm without weighting factors is proposed to balance the flying capacitor (FC) voltages and neutral-point (NP) voltage. Furthermore, according to use of three basic voltage vectors to synthesize the reference voltage vector, FSF can be achieved. Finally, the effectiveness of the proposed FCS-MPC is verified in the experiment.