The Optimization Research Based On The Topology Structure Of NPC Three-level Inverter

Due to its high voltage utilization,high output voltage and less harmonic components,multi-level inverter has been widely used in the field of high power and high voltage inverter.Based on the neutral point clamp(Neutral Point Clamped,NPC)three-level inverter topology optimization method,the following three aspects have been researched in this paper.First of all,based on the basic topology of NPC three level inverter,the working mechanism of three level inverter is expounded.In order to optimize the basic topology of NPC inverter,this paper introduced Z-source network to form a new NPC-type three-level Z-source network inverter.The small vector compensation method and a direct zero vector assignment method was proposed,which can solve the midpoint potential fluctuation and the upper and lower bridge arms flow problem.Meanwhile,The algorithm has also been optimized.After then,according to the basic principle of space vector pulse width modulation of two-level inverter,the basic method of SVPWM control of NPC three-level inverter is analyzed.The reference vector space vector is used to determine reference voltage space vector location,basic voltage space vector action time and action sequence.Finally,the simulation model of the proposed topology above verify the correctness and SVPWM algorithm.In addition,it has certain superiority in the obvious boosting capacity,the small fluctuation of midpoint potential and the more sine of current and voltage waveform.In short,the expected requirement can be reached by employ that method proposed in this paper.