一种改进的无轴承开关磁阻电机数学模型

Improved mathematic model of bearingless switched reluctance motor

类似于常规开关磁阻电机,无轴承开关磁阻电机的定、转子极宽并非总是相等,通常转子极宽略大于定子极宽,在建立数学模型时应当考虑这一因素。现有的无轴承开关磁阻电机数学模型都存在电机定、转子极宽相等的约束。考虑无轴承开关磁阻电机定、转子极宽可能存在的不相等因素,采用基于直线磁路和变椭圆系数的椭圆形磁路分割法求取气隙磁导,推导出无轴承开关磁阻电机的通用数学模型,使其不仅适用于定、转子极宽相等,而且适用于转子极宽大于定子极宽的情况。以实验室样机为例,将基于所建模型的分析结果与有限元分析结果进行了对比,验证了所建数学模型的正确性,精确度满足工程要求。应用所建立的无轴承开关磁阻电机数学模型,分析了定、转子极宽不等对悬浮力和转矩的显著影响。

Bearingless switched reluctance motor （SRM） presents a similar pole shape of stator and rotor with respect to the conventional SRM. The pole width of rotor does not always equal to that of stator, mostly the former is bigger than the latter, which should be taken into account when modeling. However, the existing models have the limitation with the same pole width of stator and rotor. To overcome this constraint, a general model that is suitable not only for the same pole width of stator and rotor, but also for their unequal pole widths, was built. The proposed model employed the gap magnetic paths partly by straight lines and partly by elliptical curves with variable coefficients. The finite-element analysis based results of experimental prototype was used to verify the proposed model. The torque and radial forces for different pole widths of stator and rotor were analyzed by using the proposed mathematic model, and the results show that there are great influence on the radial force and torque when using unequal pole widths of stator and rotor.