Selective Harmonic Elimination for a Cascade Multilevel Inverter

This paper presents selective harmonic elimination method for cascade multilevel converters to eliminate the specified harmonics in the output voltage. The principle of the converter is analyzed. Then the switching angles are computed to eliminate the low order harmonics in theory. And the gating signals for the converter are given. An experimental 7-level H-bridge multilevel converter was used to implement the algorithm and to validate the methods. The experimental results show that the method can effectively eliminate the specific harmonics as expected