The Research On Governing System Based On Three-Level Inverter

Multi-level inverter was a kind of inverter device which was proposed in the early 80's the last century that was applicable to the field of frequency control in the high Voltage.This kind of topology can reduce devices's stress and improve the output waveform quality.Inverter is the core of High-voltage inverter,it is prospected in the industrial society which advocates thrift and reducing costs.It's dynamic performance is favourable and the control theory is well.The phase and amplitude of the output is easy to control and regulate.The harmonic's content of the output is low,that can reduce the disadvantage of harmonic.So it plays an important role in the utilizing of clean energy also improves the stability of the system.The paper describes the structure of three-level inverter. Analyse the advantage of three-level inverter(NPC) compared to the traditional two-level inverter, indicates the significance of this topics. research the conversion of switch between work status,points out a important issue-the balance of neutral-point balance,and research the effect to the balance of neutral-point balance caused by difference of voltage vector,conclues the idea of controlling the neutral-point balance through controlling the neutral-point current and brings forward two control strategy to maintain the neutral-point voltage's balance.As to the control strategy of inverter, the paper adoptes space vector method, provides theoretical foundation for the controlling of inverter and the designing of software.Implemente the simulation of vector control system by founding MATLAB stimulink model.Control strategy is approved by founding SVPWM mathematic model.Finally,build experimental platform.Design main circuit,electrify cushion circuit,PWM signal generate,current and voltage sampling,IGBT drive and protect circuit,and design electrify cushion program,current and voltage sampling program,SVPWM program.