三相四桥臂逆变器调制策略的仿真研究.doc

摘 要 随着电力电子技术的发展，采用PWM三相三桥臂逆变电路把直流转换为交流供给三相负载是一种目前常用的方法。但这种方法没有中线。对于三相对称负载(如三相交流电机)可以得到三相对称的相电压。但是如果三相负载不对称就会造成相电压不平衡。为此需要设置三相中线，通过中线的控制来保证在非对称负载下三相相电压的对称。近些年一种采用三相四桥臂逆变器的方案受到关注。这种三相四桥臂逆变器结构紧凑、体积重量小、效率高，在增加一个桥臂的同时，也增加了一个自由度，因而其控制也变得比较复杂。 本论文在总结、分析其它控制方法的基础上，建立了三维空间矢量控制方法。与其它控制方法相比，该方法具有电压利用率高、开关频率相对较低、控制灵活、便于数字控制实现等优点。并应用Simulink中的模块搭建电路模型，进行仿真。仿真结果证明该方法具有良好的控制效果。 关键词：三相四桥臂；逆变器；三维空间矢量；仿真 Abstract With the development of electric power and electron technology, that adopting the PWM three-phase three bridges inverter to making DC to AC for three-phase loads is in common used at present. For it has not neutral line, only symmetrical loads of three-phase (such as AC Motor) can get the symmetrical three-phase voltage. When the three-phase loads are asymmetric, three-phase voltage is unbalanced. For that reason, it is needed that using neutral line to assure three-phase voltage is balanced. In recent years, three-phase four bridges inverter is paid close attention. This inverter has the merit of compact structure, small bulk factor and efficient. Three-phase four bridges inverter added a bridge based on three-phase three bridges inverter, has a more complex control method. Based on analyzing other control methods, this paper designed three dimension space vector PWM algorithm. Compared with other ways, this method has some merits of high efficiency, low IGBT frequency, easy to control and digitalization. Simulated this model with Matlab, the result proved thethree-dimension SVPWM was fit for controlling three-phase four bridges inverter. Key words: three-phase four bridges；Inverter； three-dimension space vector control；simulation 目 录 摘要．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．I ．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．II．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．1.1 课题的根据和意义．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．.2 三相四桥臂逆变器的发展概况．．．．．．．．．．．．．．．．．．．．．．．．