随机零矢量分配空间矢量PWM的谐波分析

Harmonic Analysis of Random Zerovector Distribution Space Vector Pulsewidth Modulation

摘要:

分析了在空间矢量脉宽调制下电机磁链误差产生的本质原因,给出了理论上的磁链误差带; 根据纹波电流推导出了随机零矢量分配空间矢量脉宽调制（RZDPWM）策略下磁链/电流谐波在微观(开关周期)和宏观(基波周期)上畸变率的理论表达式.最后,对理论表达式进行了分析讨论,揭示了RZDPWM的一些本质性特征,并用仿真实验对理论分析进行了部分验证.得出:在调制比较大时RZDPWM的随机效果降低,均方值对随机数的数字特征具有较大的依赖性,误差三角形沿着磁链圆形轨迹的随机前进是频谱展开的本质原因.

Abstract:

The sources of the flux error were analyzed,and the theoretic flux error region was proposed in the motor control based on the space vector pulsewidth modulation.The harmonic distortion factor formula was deduced through the ripple current on the microscopic level (switching period) and macroscopic level (fundamental period).Finally the formula was analyzed,and some essential characteristics of the random zerovector distribution pulsewidth modulation (RZDPWM) were revealed.The simulation results verify the theoretic analyses.The results show that the performance decreases with the modulation index reaching the maximum value,the meansquare value is highly dependent on the numerical characteristic of the random variable,and the random movement of the error triangle along the flux/current circle is the key element that makes the spectrum expanded.