Comparison of modulation strategies for a cascaded H-bridge StatCom: Part 2: application of the analysis

A companion paper provided the theoretical basis for a comparison between phase shifted carrier and space vector modulation schemes. This paper utilises the analysis techniques developed to investigate some non-ideal implementation aspects of the modulation strategies as well as the effect of increasing the level number on the performance of the cascaded H-bridge static compensator (H-StatCom). Specifically, non-ideal elements of the modulation scheme, such as non-uniform DC bus voltages, carrier phase-shift error and transient capacitor voltages are discussed. Simulation results are presented which show that there is an important relationship between the performance of the phase shifted carrier technique and the number of levels in the H-StatCom.