Design and analysis of novel optimal harmonic elimination strategy based on MOPSO to obliterate low‐order harmonics of odd‐nary cascaded transformers‐based multilevel inverter

Abstract

Creating a high‐step staircase sinusoidal voltage taking into account of low number of switches is recognized as a significant challenge ahead of inventors of power electronics. This paper suggests a maiden cascaded transformer‐based multilevel inverter to effectively develop and solve the abovementioned challenge. Hence, via appending the bidirectional switches to the capacitors of submultilevel inverter as well as low‐frequency transformers, the proposed inverter structure can flexibly operate as so‐called “odd‐nary asymmetrical multilevel inverter.” From the perspective of low‐order harmonics produced by all inverter structures, apart from inverter type, it is essential that an effective strategy to be implemented to eliminate these harmonics. Toward this subject, kerf‐style Selective Harmonic Elimination Pulse Width Modulation (SHEPWM) has been scheduled as an optimization problem. Because of nature of multiobjective state of the problem, application of the multiobjective optimization technique is inevitable. Considering significant performance of Multi Objective Particle Swarm Optimization (MOPSO) for solving the nonlinear objectives, the elimination of fifth, seventh, and 11th harmonics is formulated by relevant fitness functions based on MOPSO. Putting it all together, the relevant analytical study accompanying both the simulation and experimental results has transparently verified the performance of the proposed multilevel inverter. Furthermore, elimination of all three designated low‐order harmonics, ie, fifth, seventh, and 11th harmonics using MOPSO‐based kerf‐style SHEPWM strategy has been well confirmed.