A modified harmonic elimination method with a wide range of modulation indices for multi-level inverter with unequal DC-sources

This paper presents a novel modulation technique applied in multi-level inverters with unequal DC sources suitable for wide range of modulation indices. This method considers all the possible switching schemes assuming that the power devices in the different converter modulus can turn ON/OFF up to twice per period. Also, a unified approach using Homotopy algorithm is presented to solve the harmonic elimination equations for all various switching schemes. A three-phase seven-level Y-connected cascaded inverter is modeled in this paper. Experimental results indicate that the proposed technique is effective and efficient for harmonic elimination in multi-level inverter with unequal DC sources and the theoretical results are well validated.

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