三相准Z源并网逆变器的简单升压改进空间矢量调制策略

Simple Boost Modified Space Vector Modulation Strategy for Three-Phase Quasi-Z-Source Grid-Connected Inverter

提出一种大升压比三相准Z源并网逆变器及其三种简单升压改进空间矢量调制(SVM)策略,把两种已有的改进SVM用作简单升压调制,并对该逆变器采用五种简单升压改进SVM策略下的逆变桥和阻抗网络二极管开关损耗、储能电感损耗、储能电感和滤波电感电流纹波、输出并网电流总谐波失真(THD)等性能参数进行深入的比较研究,得出采用直通矢量位于零矢量与有效矢量之间的四段直通简单升压改进SVM时该逆变器综合性能最优。准Z源并网逆变器由大升压比准Z源阻抗网络、三相逆变器级联构成;简单升压改进SVM策略具有最大化利用零矢量作用时间、功率管开关损耗和电压应力小、升压能力强等优点。实验验证了该逆变器的可行性和理论分析的正确性,为实现低输入电压或宽变化范围输入电压的光伏、风力等新能源并网发电系统奠定了关键技术基础。

This paper proposes a three-phase quasi-Z-source grid-connected inverter with strong boost ability and three kinds of simple boost modified space vector modulation（SVM） strategies.Two existing kinds of modified SVMs were used as the simple boost modulation.The characteristics of the inverter with five kinds of simple boost modified SVM strategies were deeply investigated and compared,including the switching losses of the inverter bridge and the impedance network diode,the loss of the energy storage inductor,the current ripples of the energy storage inductor and the filter inductor,and total harmonic distortion（THD） of output grid-connected current.It is concluded that the overall performance of the inverter is the best with the simple boost modified SVM that has four shoot-through segments between active vectors and traditional zero vectors.The quasi-Z-source grid-connected inverter is composed of a large boost ratio quasi-Z-source impedance network and a three-phase inverter.The simple boost modified SVM strategy has many advantages,such as fully utilizing zero vector action time,low switching loss and voltage stress,strong boost capability.The feasibility of the inverter and the correction of theory analysis were verified by the experiments.It lays a key technical foundation on new energy grid-connected power generation systems such as photovoltaic,wind.