级联H桥整流器的双调制轨迹控制研究

级联H桥多电平整流器的直流侧电容电压平衡问题是影响变换器整体性能的主要问题之一.从安全工作区和负载功率分配角度讨论了该问题产生的原因,并给出了级联H桥多电平整流器直流侧电容电压平衡的边界条件,在此基础上提出了双调制轨迹法,并给出了双调制轨迹法的逻辑代数描述及通用算法,使其可扩展到多H桥级联的场合.通过使用提出的控制策略,级联H桥变换器交流侧电压合成点可被强制落在边界条件上,从而可在更大的负载不平衡区间上实现直流侧电容电压的平衡.仿真结果验证了所提控制策略的有效性.

Research on dual modulation curves control of cascaded H-bridge rectifier

The balance of dc-side capacitor voltage is one of the dominant problems that affect the overall per- formance of a cascaded H-bridge rectifier （CHBR）. This article has analyzed the problem by considering the safe operation area of the CHBR, as well as the load power distribution. The balancing boundary condition of capacitors voltage has been defined, from which a dual modulation curves control strategy for balancing the ca- pacitors voltage of CHBR were proposed. Furthermore, the logic expression and the algorithm of dual modula- tion curves strategy have also been discussed to handle with multiple cascaded H-bridges situation. With the proposed control strategy, the ac-side voltage synthesis point is forced to the balancing boundary condition, which helps the balance of dc-side capacitors voltage in a relative wider range of unbalanced load condition. The simulation results are presented to verify the performance of the proposed control strategy.