Improved NP-SVM suitable for multi-sampling used in high power NPC rectifiers without even order harmonics

In order to eliminate the even order harmonic currents of the NPC rectifiers, the modified SVM (short for NP-SVM) is proposed in the past. However, when the NP-SVM is used in the multi-sampling system, there will be direct jumps between N and P which can result in narrower pulse width, higher dv/dt, even the destruction of devices, which is very undesirable. In this paper, the reasons of direct NP jumps generation are briefly analyzed at first, then an improved NP-SVM(INP-SVM) suitable for multi-sampling system is proposed to overcome the problems in high power three level NPC rectifiers. Finally, all these analyses and the effectiveness of the proposed NP-SVM are firstly validated by simulation, and then are verified further in a 75kVA laboratory prototype.