数字SPWM调制信号截尾误差的补偿方法研究

Compensation Method for Modulation Signal Truncation Error of Digital SPWM

电力电子变换系统中,数字SPWM调制信号的截尾会带来误差,当调制信号幅值很低时,这个误差可能会大到严重影响系统的正常运行。设计了一种调制信号小数部分循环累加的补偿算法来消除误差,分析了数字调制信号截尾误差的产生原因,提取调制信号中被截尾的小数部分,并对小数部分进行循环递推累加补偿。与传统的调制信号小数直接被截尾相比,本文方法提高了调制信号的精度,减小了系统的控制误差,特别适用于数字SPWM调制信号幅值较低的应用场合。仿真和实验结果验证了小数补偿算法的有效性。

The error can be caused by the digital SPWM modulation signal truncation in power electronic conversion system. When the amplitude of the modulation signal is the minimum, the error may be too large to affect the normal operation of the system seriously. The paper designs a compensation algorithm based on the cycle accumulation of the decimal part to eliminate the error, analyzes the error cause. The decimal part of the modulation signal is extracted by the method and compensated through the cycle recursion accumulative compensation algorithm. Compared with the traditional solutions of the decimal part, the method proposed in this paper improves the accuracy of the modulation signal and reduces the error of the system, is particularly suitable for the applications of digital signal SPWM modulation with lower amplitude. The effectiveness of the decimal compensation algorithm is verified by the simulation and experimental results.