The voltage balance control for new generation of high power cascaded H-bridge rectifier

The control strategy of cascaded rectifier which is used as the first stage of a new generation cascaded line-frequency transformerless power converter is discussed in this paper. The circuit model of cascaded rectifier stage is simplified, and the mathematical model of cascaded rectifier stage is set up based on Single-Phase Rotating Frame. A balance strategy for DC link capacitor voltage of each cascaded cell by distributing the cell switching for the synthetic waveform is proposed. The simulation results indicate that this proposed strategy can balance the DC link capacitor voltage of every cell in better accuracy, and control the active or reactive power of the system more effectively.