Suppression of harmonics of a multilevel converter applied for a back-to-back HVdc link

This paper proposes a new pulse width control method to suppress the higher harmonics of the output of a multilevel converter applied for a back-to-back (BTB) HVdc link. A multilevel converter can reduce the snubber loss and the switching loss since it decreases the number of switching devices connected in series and the switching frequency. The staircase voltage waveform is expected to be able to suppress the higher harmonics. We investigated the condition necessary to suppress the higher harmonics and propose a method for controlling the fundamental voltage amplitude. We show the effectiveness of the proposed control method based on simulation results obtained using Alternative Transient Program (ATP). (C) 2003 Wiley Periodicals, Inc.