Z源三相四桥臂逆变器的三维空间矢量脉宽调制策略

对Z源三相四桥臂逆变器的稳态工作原理进行了深入分析,并提出一种改进的三维空间矢量脉宽调制策略,通过合理地选择直通桥臂,将直通状态插入到传统零矢量状态中,保证不影响有效开关状态和输出电压。同时,分析了直通占空比和调制比的耦合关系,得出直通占空比的最大取值,进而提出相应的最大恒定升压控制策略。在MATLAB/Simulink中搭建Z源三相四桥臂逆变器仿真模型,并在平衡及不平衡负载工况下进行仿真。仿真结果表明:Z源三相四桥臂逆变器在所提三维空间矢量脉宽调制策略下,不仅可以实现升压控制,而且相较传统Z源三相三桥臂逆变器,在不平衡负载条件下也能取得良好的控制效果。

ThreeDimensional Space Vector Pulse Width Modulation Strategy forZSource ThreePhase FourLeg Inverter

The steadystate operation principle of Zsource threephase fourleg inverter was analyzed, and an improved threedimensional space vector pulse width modulation (3DSVPWM) strategy was proposed. By properly selecting the shootthrough leg, the shootthrough states were inserted into the traditional zerovector state on the premise that the active switching state and output voltage were not affected. At the same time, the coupling relationship between the shootthrough duty ratio and the modulation ratio was analyzed, and the maximum value of the shootthrough duty ratio was obtained. Then the corresponding maximum constant boost strategy was proposed. A simulation model of the Zsource threephase fourleg inverter was built in MATLAB/Simulink and simulated under balanced and unbalanced load conditions. The simulation results showed that the Zsource threephase fourleg inverter could not only achieve boost control under the proposed 3DSVPWM strategy, but also achieve good control results under unbalanced load conditions compared with the traditional Zsource threephase threeleg inverter.