摘要
载波相移SPWM技术应用于级联型多电平逆变器,其载波相移角度差π/N和2π/N两种相移方式,对不同级联数目的逆变器输出有不同影响。当三相逆变器中功率单元发生故障被切除后,输出电压不再平衡。而利用中性点偏移技术,可使逆变器输出线电压重新达到平衡,从而具备较好的容错能力。通过对载波相移PWM技术和中性点偏移原理的数学推导,得出采用载波相移角π/N方式与中性点偏移技术,逆变器输出性能有较大提高的结论。最后对级联型九电平逆变器A相中某一功率单元故障后状况进行仿真实验,验证了数学推导的正确性。
Cascade multilevel inverter output voltage have different performance when two carrier phase-shifted modes of π/N and 2π/N because of the different number of cascade unit. The output voltage of three phase inverter can not keep balance when faulty cells are isolated. However, the line voltage can balance again with better fault tolerant ability when the neutral-shift technique is used. The carrier phase-shifted SPWM and neutral-shift theory are analyzed by mathematics illation and the conclusion that the inverter performance is improved by applying π/N mode and neural-shift technique. Finally, when one faulty power cell of A phase is isolated in the cascade ninelevel inverter, the simulation results verify the validity of the mathematics reasoning.
出处
《电气传动自动化》
2009年第4期1-5,共5页
Electric Drive Automation
