Novel phase shifted carrier modulation for a cascaded H-bridge multi-level StatCom

Phase shifted carrier modulation enforces harmonic cancellation through each phase-leg in a multi-level H-bridge StatCom (H-StatCom). The implementation of this scheme, while achieving excellent harmonic performance suffers from control interactions between the voltage balancing loops. This paper first analyses these interactions and then develops a phase shifted carrier modulation scheme which avoids the loop interactions by exploiting an extra degree of freedom in the available switching states. Simulation and experimental results are presented that confirm the correct operation of the modulation strategy.