System and method for optimizing fundamental frequency modulation for a cascaded multilevel inverter

摘要

A system and a method for optimizing fundamental frequency modulation in a cascaded multilevel inverter (CMI) are provided. The CMI includes at least a first H-bridge module and a second H-bridge module connected in series with the first H-bridge module. The first H-bridge module is operated according to a first duty cycle and the second H-bridge module is operated according to a second duty cycle. The first duty cycle is greater than the second duty cycle. The first and second H-bridge modules are controlled utilizing fundamental frequency modulation. A portion of the first duty cycle is transferred to the second duty cycle thereby optimizing fundamental frequency modulation by at least improving power sharing between the first and second H-bridge modules and improving equalization of DC capacitor currents and voltage ripples while maintaining the same fundamental modulation to the output voltage waveform.