过调制区内三电平SVPWM与CBPWM算法的统一性研究

Unity Studies Between Three-level SVPWM and CBPWM in the Over-modulation Region

有效使用过调制策略可提高直流电压利用率,加快电机的动态响应速度,扩大其稳定运行区域。为了揭示过调制区内三电平空间矢量脉宽调制(space vector pulse width modulation,SVPWM)和载波脉宽调制(carrier-base pulse width modulation,CBPWM)算法的内在联系,在分析SVPWM过调制原理的基础上,用两种方法从不同角度推导与SVPWM等效的CBPWM形式。第1种方法根据伏秒平衡原理推导出与SVPWM等效的CBPWM调制函数中应注入的零序分量表达式;第2种方法根据规则采样规律推导出以调制度为自变量的与SVPWM等效的CBPWM整个调制函数形式。理论研究表明:在过调制区内同样可以用CBPWM方法实现与SVPWM相同的效果。仿真和实验结果验证了理论分析的正确性与有效性。

Making effective use of over-modulation strategy can not only enhance the utilization of dc voltages, but also speed up the dynamic response of the motor and extend its operating boundary. In order to reveal the relationship between three-level space vector pulse width modulation（SVPWM） and carrier-base pulse width modulation（CBPWM） in the over-modulation region, this paper firstly analyzed the principle of over-modulation algorithm. Then, two different methods were adopted to derive the CBPWM equivalent to SVPWM. Based on the principle of volt-second balance, the injected zero components were deducted in the first method. The second method was based on the rules of regular sampling, deriving the modulating functions of CBPWM equivalent to SVPWM. Theoretical analysis shows that CBPWM can also achieve the same effects as three-level SVPWM in the over-modulation region. The validity and effectiveness of the theoretical analysis were verified by simulation and experimental results.