Research On SVPWM Algorithm And Midpoint Potential Control Of Asymmetrical Three-phase Four-level Inverter

In recent years,in the context of the global energy crisis and environmental pollution,clean energy such as wind energy,solar energy and ocean energy have gradually become part of the energy consumption of all countries in the world,and their proportion has been increasing year by year.With the continuous access of new energy sources,there is an urgent need to increase research on high-efficiency and high-quality power conversion devices.As one of the core technologies of power conversion devices,multilevel inverter technology is increasingly becoming a research hotspot at home and abroad.Compared with the traditional two-level,asymmetric multi-level inverter has the advantages of low withstand voltage of power switching devices and low equivalent switching frequency under the same output waveform quality.Because it does not require clamping devices,it has high cost performance and Features such as simple topology.In view of this,this article takes an asymmetric three-phase four-level inverter as the research object.First,through in-depth analysis of the topology,modal and space voltage vector control strategies,and focusing on the switching frequency and voltage of the traditional SVPWM algorithm For the disadvantage of higher stress,an improved space vector pulse width modulation algorithm is proposed.Simulation and experimental results show that under the same output waveform,the switching frequency of the improved algorithm is lower than that of the traditional algorithm,and the voltage stress of the switch tube is smaller.The improved algorithm also obtains better results in the 400 Hz intermediate frequency inverter output.effect.Secondly,this article adopts a multi-output Boost auxiliary circuit mid-point potential control method to solve the problem of mid-point potential fluctuation of asymmetric three-phase four-level inverter.Simulation and experimental results show that this method can effectively suppress the mid-point potential.Fluctuations.Finally,an experimental verification platform was built under laboratory conditions,and the digital signal processor(DSP)of Texas Instruments was used as the main control chip of the entire system to complete the inverter main circuit,isolation drive circuit and signal detection circuit and other hardware The circuit design and the corresponding DSP program provide the necessary conditions for further verifying the correctness and effectiveness of the content studied in this article.