多电平Z源逆变器脉宽调制及应用研究

发布时间：2018-01-16 05:30

本文关键词：多电平Z源逆变器脉宽调制及应用研究　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：传统DC/AC逆变器包括电压源型逆变器和电流源型逆变器,它们存在固有局限性。Z源逆变器在直流电源和逆变桥之间耦合一个X型阻抗网络,使其有效克服传统逆变器的不足,拥有单极升降压的优越特性,在分布式发电等新能源应用场合具有较强的优势。在介绍两电平Z源逆变器的一般拓扑及其升压原理的基础上,根据Z源逆变器对直通插入的要求,研究了其常规PWM方法:简单升压控制、最大升压控制、最大恒升压控制、修正调制波控制及SVPWM方法。重点介绍了在传统PWM调制方法中插入直通状态的规律和原则,并比较分析了上述各调制方法。为实现三电平逆变器的升压输出,讨论了单Z源网络双直流电源NPC三电平Z源逆变器拓扑结构,分析其升压原理及直通方法,推导直通时间与升压倍数的关系,着重研究了单Z源网络NPC三电平Z源逆变器的直通升压PWM方法,包括直通插入的同向载波层叠PWM、交替反向层叠PWM及基于参考电压矢量分解的SVPWM算法。针对单直流电源电容分压式NPC三电平Z源逆变器存在的中点电压不平衡问题,研究了一种基于双调制波技术的中点电位平衡控制方法,合理设计上下直通状态的插入位置,动态调节中间电压调制波,在消除中点电位低频波动的同时有效抑制中点电位偏移,且不增加逆变器开关损耗。根据传统五电平拓扑结构,推导得出了级联Z源五电平逆变器、四Z源网络和双Z源网络NPC五电平Z源逆变器三种拓扑结构,并分析了这三种逆变器的升压原理及直通方法。研究了级联五电平Z源逆变器的单极倍频载波移相SPWM方法和双极性载波移相SPWM方法,并设计了双Z源网络NPC五电平Z源逆变器的同向载波层叠PWM方法。针对Z源逆变器优越的单极升压特性,研究了Z源逆变器在不稳定直流输入的分布式发电并网系统中的应用。采用有功电流及无功电流解耦控制,实现高功率因数并网。
[Abstract]:The traditional DC/AC inverter includes voltage source inverter and current source inverter. They have inherent limitation. Z source inverter coupling an X type impedance network between DC power supply and inverter bridge. It can effectively overcome the shortcomings of the traditional inverter and has the superior characteristics of unipolar voltage lifting. It has a strong advantage in new energy applications such as distributed generation. On the basis of introducing the general topology and boost principle of two-level Z-source inverter, according to the requirements of Z-source inverter for direct insertion. The conventional PWM methods are studied: simple boost control, maximum boost control, maximum constant pressure control. Modified modulation wave control and SVPWM method. The rule and principle of inserting through state in traditional PWM modulation method are introduced emphatically. In order to realize the boost output of three-level inverter, the topology structure of NPC three-level Z-source inverter with single Z-source network and dual-DC power supply is discussed. Based on the analysis of the principle and method of booster, the relationship between direct-through time and boost multiple is deduced, and the PWM method for three-level NPC three-level Z-source inverter with single Z-source network is studied emphatically. A codirectional carrier stacked PWM including direct-through insertion is included. Alternating reverse stack PWM and SVPWM algorithm based on reference voltage vector decomposition. The neutral-point voltage imbalance of single-DC power supply capacitive split voltage NPC three-level Z-source inverter is discussed. In this paper, a control method of midpoint potential balance based on dual-modulation wave technology is studied. The insertion position of the up-down through state is reasonably designed and the intermediate voltage modulated wave is dynamically adjusted. In order to eliminate the low frequency fluctuation of neutral point potential and effectively suppress the offset of neutral point potential without increasing the switching loss of the inverter, the cascaded Z-source five-level inverter is derived according to the traditional five-level topology. There are three topologies for four-Z source network and dual-Z-source network NPC five-level Z-source inverter. The boost principle and direct-through method of these three kinds of inverters are analyzed. The single-pole frequency-doubling carrier phase-shifted SPWM method and bipolar carrier phase-shifted SPWM method of cascaded five-level Z-source inverter are studied. The codirectional carrier stacked PWM method for NPC five-level Z-source inverter with dual Z-source network is designed. The application of Z-source inverter in the distributed grid-connected generation system with unstable DC input is studied. The active and reactive current decoupling control is used to realize the grid-connected system with high power factor.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM464

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