Z源三相四桥臂逆变器的三维空间矢量脉宽调制策略

Three-Dimensional Space Vector Pulse Width Modulation Strategy for Z-Source Three-Phase Four-Leg Inverter

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。

The steady-state operation principle of Z-source three-phase four-leg inverter was analyzed,and an improved three-dimensional space vector pulse width modulation(3D-SVPWM)strategy was proposed.By properly selecting the shoot-through leg,the shoot-through states were inserted into the traditional zero-vector state on the premise that the active switching state and output voltage were not affected.At the same time,the coupling relationship between the shoot-through duty ratio and the modulation ratio was analyzed,and the maximum value of the shoot-through duty ratio was obtained.Then the corresponding maximum constant boost strategy was proposed.A simulation model of the Z-source three-phase four-leg inverter was built in MATLAB/Simulink and simulated under balanced and unbalanced load conditions.The simulation results showed that the Z-source three-phase four-leg inverter could not only achieve boost control under the proposed 3D-SVPWM strategy,but also achieve good control results under unbalanced load conditions compared with the traditional Z-source three-phase three-leg inverter.