宽转子极无轴承开关磁阻电机径向力模型全周期拓展

Full-period extension of radial force model for bearingless switched reluctance motor with wide rotor

针对单绕组宽转子极无轴承开关磁阻电机在定转子极非完全交叠区间的径向悬浮力模型空白、已有定转子极完全交叠区间径向悬浮力模型推导过程复杂且计算量大的不足,首先通过磁场有限元分析,分别确定了该电机在定转子非完全交叠区间和完全交叠区间的电磁场几何分布,计算了气隙磁密,再根据麦克斯韦应力法分别推导了这2个区间的径向力表达式,从而建立该电机在一个完整周期范围内的径向力数学模型,并通过与三维有限元计算结果的对比验证该模型的准确性。相比于利用等效磁路图推导径向力模型而言,该建模过程更简便,计算量也更小。全周期径向力模型的建立,不仅能为电机本体和控制器设计提供理论参考,还有助于提高该电机控制策略设计的灵活性,也可以提高与传统单绕组无轴承电机控制器的通用性。

For single winding bearingless switched reluctance motor with wide rotor(BSRMWR),there is still no radial suspension force model when rotor poles are not completely overlapped with stator poles.The existing radial suspension force model even has the shortcomings of complex derivation process and large amount of calculation when rotor poles are completely overlapped with stator poles.Therefore,the geometric distribution of the electromagnetic field of single winding BSRMWR both in the incompletely overlapping region and in the completely overlapping region of stator poles and rotor poles were analyzed with the magnetic field finite element analysis respectively,and the expressions of air gap magnetic density were obtained.Then the radial force expressions in these two regions were derived respectively according to the Maxwell stress method,and the mathematical models of the radial force of single winding BSRMWR in a full period were established.Finally,the accuracy of the deduced models was verified by comparing with the three-dimensional finite element calculation results.Compared with the equivalent magnetic circuit diagram method,the presented modeling process is simpler and less computational.The establishment of full-period radial force models can not only provide theoretical reference for the design of single winding BSRMWR and its controller,but also can help to improve the flexibility of the control strategy design and the versatility with the traditional single winding bearingless switched reluctance motor controller.