Modified high frequency phase disposition pulse width modulation for modular cascaded H-bridge multilevel converters

Modulation plays a vital role for the proper and reliable operation of power converters. For high power and medium voltage applications, cascaded H-bridge (CHB) multilevel converters (MLC) are becoming industry standard. In this article, a modified high frequency phase disposition pulse width modulation (PDPWM) technique is proposed. The proposed technique is applied to 1.0 MVA 3.0 kV, 3-phase 5-level CHB converter to validate the improved performance regarding total harmonic distortion (THD), suppression of lower order harmonics and less bulky filtering circuitry. As a reference for modulation, third harmonic injected sixty degree bus clamped signals are applied to the proposed phase disposed carrier signals. All the simulation works are carried out in MATLAB/Simulink environment.