考虑谐波影响的开关磁阻电机无位置技术研究

The research for sensorless control of switched reluctance motor considering harmonic effects

针对用传统傅里叶级数相电感模型估计开关磁阻电机转子位置时直接忽略高次谐波,仅考虑到基波或者二次谐波,导致位置估计精度不高的问题,提出了一种考虑谐波影响的开关磁阻电机无位置控制方法.该方法通过对电感进行坐标变换以及差值电感辨识,消除了傅里叶级数电感的直流分量、偶次谐波分量以及三的倍数次谐波分量.选取谐波含量最少的差值电感构建角度--差值电感关系数学模型,利用其特征点估算转子位置.为了验证所提算法的有效性以及正确性,以一台12/8极开关磁阻电机为控制对象,进行了仿真以及实验.实验结果表明,减少电感谐波后估计转子位置精度提高,且在较大电流条件下用差值电感估计转子位置角度时,位置估计精度几乎不受电机磁饱和因素的影响.

For sensorless control of switched reluctance motor(SRM)based on inductance expressed by Fourier series,the position estimation accuracy of SRM is not high enough caused by ignoring the high-order harmonics directly and only considering the fundamental or the second-order harmonics when estimating SRM rotor position.To solve this problem,the sensorless control method of SRM considering the influence of harmonics is proposed.Through coordinate transformation and difference inductance identification,the dc component,even harmonic component and multiple harmonic component of Fourier series inductance are eliminated.Then the difference inductance with the least harmonic content is selected as the inductance curve to estimate the rotor position.The mathematical model of angle-difference inductance relationship is constructed.Rotor position is estimated by using characteristic points.To verify the effectiveness and correctness of the proposed algorithm,simulation and experiment are carried out on a 12/8 pole SRM.Experimental results show that the accuracy of rotor position estimation is improved after reducing the inductance harmonics.Meanwhile,it is almost not affected by the saturation factor of the motor when the differential inductance is used to estimate the rotor position angle under the condition of large current.