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

Abstract

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.