A novel modulation strategy based on two dimensional modulation for balancing DC-link capacitor voltages of cascaded H-Bridges Rectifier

In this paper, a novel modulation strategy based on two dimensional modulation is proposed, which can not only achieve fast balancing DC-link capacitor voltages for each cell in the cascaded H-Bridges Rectifier (CHBR), but can also extend the stable operating range to the maximum with heavy unbalanced loads under unity power factor. The control method has been fully investigated with detailed theoretical analysis, the performance of the proposed modulation strategy is evaluated with two H-bridges in cascade using the simulation results obtained from the Matlab/simulink. It is shown that the dynamics of the system for balancing the DC link capacitor voltages of each cell is considerably improved with very fast response time even at very heavy unbalanced load, and in whole the process, the input of the CHBR maintains in unity power factor.