Research on Voltage Balancing Control Method with the Offset Component and Fundamental Component Injection for Cascaded H-Bridge Rectifier

With the advantage of higher equivalent switching frequency and lower volume of filter, cascaded H-bridge rectifier has potential applications in high voltage and aviation. In order to make the system run reliably, the voltage balancing control is needed. Existing voltage balancing methods have limited balancing range under carrier phase shift modulation. In this paper, a voltage balancing method with mixed injection of offset and fundamental components is proposed. Compared with the traditional fundamental component injection voltage balancing method, it has many advantages. It can expand the working range under unbalanced load. The adjustment speed is faster and the error is smaller. The new method can be used to improve the reliability of the system and can be implemented by analog circuits. Simulation verify the validity and correctness of the proposed method.