Research On NPC Three-level SVPWM And Neutral-Point Voltage Balance

Abstract: The three-level inverter based on TMS320F2812DSP was developed to improve the power electronics device voltage grade,reduce harmonic content of the inverter output voltage and the switch loss of the power electronics device.this article designs control scheme which base on the topological structure of diode-clamped three-level converter and SVPWM,which researchs motor stator field oriented control ,and which pays emphasis on the analysis about space coordinate transform,sector judgment,triangle region partition divided,vector function order,vector function time of the three-level inverter;this article analysis the neutral voltage fluctuation of the three-level inverter, which can get the conclusion that adjust Positive and negative small vector action time can Inhibit neutral voltage fluctuation.At the same time this article designs the 485communication system base on Modbus protocol.The Model of two-level and three-level is built in this article , which analysis the SVPWM realizing process and verify the advantage of three-level inverter.The three-level inverter main circuit is designed and the three-level inverter prototype is developed, the parameter and control command of main controller is set through the supervisory computer ,the frequency conversion start,stable operation,Load disturbances and positive or negative operation of the three-level inverter is experiment .The control strategy of SVPWM is correct through the simulation analysis andthe experimental results...