An Evaluation of Spectral Characteristic of Novel Hybrid Asymmetric Modulated 9-level Inverter

This paper proposed a novel hybrid asymmetric 9-level inverter in which an asymmetric 5-level inverter and an H-bridge inverter with equal DC bus voltage are series connected. A hybrid asymmetric modulation technique for the novel inverter is illustrated. In terms of the control technique adopted, the new configuration permits faster devices and higher voltage devices operating in synergism. In the case of three carrier dispositions, the mathematic models of the modulation process are built. The rigorous analytic solution is derived from an extension of Bennet´s method, which benefits the evaluation of spectra accurately. We summarize spectral characteristics of output waveforms involving all operation conditions. Experiment is carried out to validate the feasibility of the proposed approach