新型混合不对称九电平逆变器的调制方法及输出频谱特性

介绍了一种新型混合不对称九电平逆变器,它由一不对称五电平逆变器和一全桥逆变器级联而得,级联逆变器的直流母线电压相等。该逆变器采用混合不对称调制方法,可使耐压器件和快速器件协同工作。构建了3种常用载波分布下的调制过程数学模型,从而通过Bennet扩展方法得到输出电压的严格数学表达,这有利于精确分析输出频谱。总结了所有工况下的输出波形频谱特性,并通过试验证实了所述方案的可行性。

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

It is 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. The spectral characteristics of output waveforms involving all operation conditions are summarized. The experiment is carried out to validate the feasibility of the proposed approach.