New modified CHB multilevel inverter topology with elimination of lower and higher order harmonics

Abstract

The main objective of this study is the improvement of output voltage waveform quality generated by a new modified Cascaded H-bridge (CHB) multilevel inverter using Selective Harmonic Elimination (SHE) method and passive LC filters. A PWM technique with SHE is used to control fundamental harmonic and eliminate harmonics of chosen lower-order in CHB multilevel inverter. A passive LC filter is added to the inverter in order to eliminate the high-order harmonics. The switching angles are drawn by solving a non-linear equations system using Hybrid Genetic Algorithm (HGA). In order to evaluate the performance of the HGA in solving the non-linear equations of the system presented in this study, the proposed optimization algorithm was compared to the well-known particle swarm optimization method. Different cases including 5- and 7-level inverters with different values of modulation indices are reported. The simulation findings are validated through experimental results.

Keywords

• New modified CHB multilevel inverter
• selective harmonic elimination
• hybrid genetic algorithm
• particle swarm optimization
• passive LC filter