A DC capacitor voltage balance control method of cascaded multilevel STATCOM

In this paper, a method of energy self-balancing capacitor voltage waveform superposition based on equivalent area was presented, on the basis of which a control method of the capacitor voltage offset correction using the transposition of pulse, a rotation method of specific order selecting pulse, was proposed. This method can automatically modified the offset of capacitor voltage and the quality of the output current can´t be affected. Simulation results show that the control method of cascaded multilevel STATCOM DC capacitor voltage balance is effective and feasible.