Study On Nonsymmetrical Hybrid 5-level Inverter And Its New Modulation Strategy

Multilevel inverter can output multilevel and high voltage by using low voltage stress switches,which is widely used in medium or high voltage power conversion.But when the output voltage level is equal to or greater than five,the traditional multilevel inverter has the problem of complex topology,many more switches,many more passive device,and complexity in control,which has limited its application.Hybrid multilevel inverter can improve the output of the voltage level with less power switches,which has great benefit in simplifying topology,decreasing power devices,as well as good quality of the output voltage.A new nonsymmtrical hybrid five level inverter was proposed in this paper,which can output the voltage as twice as other topology.This new topology deduced from a switch-diode-capacitor cell.Tt is the switch-diode-capacitor cell that makes this new topology having the capability to double the output voltage and also with the ablity to self-balance the capacitor voltage.Besides,a novel single carrier and dual-moudulation waves SPWM appiled to nonsymmetrical hybrid five-level inverter is introduced.This new SPWM strategy has two modulation waves and only one carrier,ant it can not only keep the voltage balance of capacitor clamped nonsymmetrical five level inverter and makes the loss balanced in double voltage nonsymmetrical five level inverter but also reduce the consumption of DSP dramaticlly,which means this control strategy can be achieved by only one ePWM moudule.