An Inter-Phase Balancing Strategy based on Model Predictive Control for Discontinuously Operated Cascaded H-Bridge StatComs

The conventional implementation of discontinuous modulation (DM) in cascaded H-bridge static compensators negatively affects the inter-phase capacitor voltage balancing, particularly during grid unbalanced conditions. This paper integrates the DM implementation and the inter-phase capacitor voltage balancing using a finite control set model predictive control approach. This advanced predictive DM implementation outperforms the conventional DM while preventing the capacitor voltages from diverging during unbalanced grid conditions. The effectiveness of the proposed strategy is verified with simulation results considering different unbalanced grid cases.