固定开关频率三电平PWM整流器直接功率控制

以三电平电压型PWM整流器的数学模型为基础,结合瞬时无功理论,推导了瞬时功率和三电平整流桥开关矢量之间的关系,提出了一种固定开关频率的三电平PWM整流器的直接功率控制方法.该方法基于空间电压矢量调制,实现了动态过程中有功功率和无功功率的解耦控制.相对于传统的开关表bang-bang控制方式的直接功率控制,该方法不仅能够实现系统对有功功率和无功功率的直接控制,而且能保证固定的开关频率,简化了滤波器的设计.实验结果表明该控制策略实现了单位功率因数控制,电流谐波小,具有良好的动态和稳态性能.

Direct Power Control With Constant Switching Frequency for Three-Level PWM Rectifier

This paper presents the mathematical model of the three-level voltage source PWM rectifier and deduces the relationships between instantaneous power and the vectors of the three-level rectifier from the theory of instantaneous reactive power. Then, a direct power control (DPC) scheme for three-level PWM rectifier with constant switching frequency is proposed. Space vector modulation (SVM) is applied to the scheme, and decoupling control for the active and reactive power during the dynamic course is realized. Compared to conventional DPC with bang-bang control by a switching table, the proposed method can not only realize the direct control for active and reactive power, but also operate under constant switching frequency. Experimental results show that unity power factor is achieved and the proposed method has the advantages of low harmonic distortion of current, excellent dynamic, and steady state performances.