基于电容箝位五电平H桥的逆变器应用

为研究基于电容箝位五电平H桥逆变器的应用,以电容箝位5电平H桥构成三相逆变器,结合电容箝位3电平和常规H桥电路的优点,并采用消谐波PWM和载波相移PWM相结合的调制策略,对所采用的逆变器拓扑及其控制策略的有效性进行了仿真和实验验证。结果表明:所采用的逆变器拓扑可以方便地得到5电平输出,提高了输出电压和功率等级;所采用的控制策略能够有效提高等效载波频率,降低滤波器的体积和容量;两种调制方法的结合可发挥各自的优势,使控制灵活、实现简单。

Application of Inverter Based on Capacitor-clamped 5-level H-bridge

The application of multilevel converter in high-voltage and high-power is investigated for its inherent advantages, and carrier-based PWM is the most common control method. Three-phase inverter based on capacitor-clamped 5-level H-bridge combines advantages of capacitor-clamped 3-level and conventional H-bridge converter. The modulation strategy integrating sub-harmonic PWM(SHPWM) and carrier phase-shifted PWM(PSPWM) is adopted, which can make use of the strongpoint of each method and has good flexibility and feasibility. The validity and availability of the inverter topology and its control strategy adopted are verified by simulation and experiment. It is illustrated that the proposed inverter topology can easily get 5-level output and improve output voltage and power rating.Moreover, with the proposed modulation strategy, the equivalent carrier frequency will be enhanced, and the filter volume may be reduced.