两电平与三电平NPC逆变器单桥臂故障重构拓扑SVPWM算法比较研究

Comparison Study of SVPWM Algorithms of the Post-fault Reconfigured Topologies for Two-level and Three-level NPC Inverters With Failure of a Leg

四开关三相逆变器(four-switch three-phase inverter,FSTPI)和八开关三相逆变器(eight-switch three-phase inverter,ESTPI)分别为两电平逆变器和三电平中点钳位型(neutral-point-clamped,NPC)逆变器的单桥臂故障重构拓扑,不同故障重构桥臂对应不同的FSTPI和ESTPI拓扑。在分析二者工作原理的基础上,对所有FSTPI和ESTPI的拓扑、空间矢量脉宽调制(space vector pulse width modulation,SVPWM)算法及其等效载波脉宽调制(carrier-based pulse width modulation,CBPWM)算法进行比较研究。理论研究表明,所有FSTPI和ESTPI都可等效为施加某些限制条件的三电平NPC逆变器拓扑,且直流电压利用率为其一半。这些FSTPI和ESTPI的SVPWM算法都分别互相等效,并且这6种拓扑的SVPWM算法等效CBPWM算法都是以两个相同的相位相差π/3的正弦波为两相调制函数与三角载波进行比较,不同之处仅在于三角载波个数。仿真和实验结果证明了理论分析的正确性与有效性。

Four-switch three-phase inverters（FSTPIs） and eight-switch three-phase inverters（ESTPIs） are the post-fault reconfigured topologies for two-level inverters and three-level neutral-point-clamped（NPC） inverters with failure of a leg, respectively, and different faulty legs are correspondent to different topologies for FSTPIs and ESTPIs, respectively. Comparison studies on topologies, space vector pulse width modulation（SVPWM） algorithms and theirs equivalent carrier-based pulse width modulation（CBPWM） algorithms of all FSTPIs and ESTPIs were done, based on analyzing theirs operation principle. Theoretical research showed that all FSTPIs and ESTPIs are equivalent to the topologies of three-level NPC inverter under some limited conditions, and the DC-link voltage utilization ratio is half of this inverter. SVPWM algorithms of all FSTPIs and ESTPIs are equivalent to one another, respectively, and the SVPWM algorithms of the FSTPIs is equivalent to a CBPWM which can be achieved by a triangle wave and two sine waves whose phases are separated by π/3 electrical angle, as to SVPWM algorithms of ESTPIs, the only difference is that the number of its triangle wave is two. The validity and effectiveness of the theoretical analysis was verified by simulation and experimental results.