基于统一PWM调制器的随机空间矢量调制

Random Space Vector PWM Based on the Generalized Modulator

常用的SVPWM中零矢量U0和U7的工作时间是平均分配的。在该文中加以改进，引入一个正比于U7工作时间的系数％，如果％从0到1变化即代表了U7工作时间从总零矢量的0％变化到100％。该文利用三角载波补偿法来实现上述改进的空间矢量调制，并经研究发现％取不同的值可以实现多种PWM调制方式，基于此该文提出了统一PWM的概念。当在不同的开关周期k0取0-1之间的随机数时则实现了随机零矢量分布的随机PWM，这种调制器使得逆变器输出电压频谱尖峰大大减小，从而降低了电机驱动系统的音频噪声和电磁干扰。实验验证了这种随机PWM的有效性和实用性。

A classical space-vector pulsewidth modulator （SVPWM） with equal duration of application of zero-state vectors U0 and U7 was modified. A variable ko（proportional to the time of application of U7） was introduced. By changing ko from 0 to 1, the duration of application of U7 can be changed from 0% to 100% of the combined application time for the sum of zero-state vectors. Correlation between modified space-vector and trianglecomparison methods （with added zero sequence） was established. The research showed that many PWM methods can be realized with different value of ko. Based on the investigation, the conception of generalized modulator was put forward. With random change of ko between 0 and 1 in every sampling interval, the RPWM of random zero-vector distribution can be realized by generalized modulator. Random PWM technology is a direct and effective way to alleviate acoustic noise in adjustable-speed system. The experiment results verified the effectiveness and practicability of the random PWM.