The Design And Application Resarch Of Three-level SVPWM Inverter

Recently, multi-level inverter has been widely applied in Power electronics, andits control strategies and topologies of power circuits are become the research focuses.Comparing with the two-level inverter, it has many advantages, such as highefficiency and good dynamic performance, making less harmonic waves and suitingfor high voltage large capacity applications. However, its basic control strategies aremuch more complicated than that of a two-level inverter, and the unbalance problemof the neutral-point may appear with the increase of the level order. If DSP digitalcontrol technique is applied to multi-level inverter, its control strategy can beoptimized and system performance is advanced, while the control circuits aresimplified.The thesis describes the development prospects of power electronics technology,multi-level inverter technology development status briefing and developmentprospects, multi level inverter several topologies and its control strategies, as well asintroduce a diode-clamped three-level inverter in the introduction part. In thesecond chapter,the paper introduces the topological structure and working principleof the diode clamped inverter, summary of requirements for control of the invertercircuit and the advantages and disadvantages, introduces the midpoint imbalance andanalyses the intrinsic reasons of neutral point potential unbalance finally. The paperintroduces the basic principle of sine pulse width vector control,introduces switchingfunction in the three level inverter and deducts voltage formulas about switchingfunction and introduces the modulation method of three level inverter, studythe unified voltage modulation method and the use the modulation method in threelevel inverter, introduces the neutral point voltage balance method, in the thirdchapter. In the fourth chapter,the paper introduces the design of the system of threelevel inverter, including hardware design and software design,introduces theF2812chip resources in the control circuit,including the event manager module, ADCmodule and PIE interrupt mechanism, also introduces the design of main circuit, theswitch of the protection circuit design and analysis the protection circuit, design ofdriver circuit design, design of circuit of voltage matching. In the last chapter, thepaper introduces simulation of the inverter for asynchronous motor speed control andanalysis the simulation diagrams of the speed, the electromagnetic torque, the d-qaxis phase DC current, three-phase current in detial.