共悬浮绕组式无轴承开关磁阻电机的基础研究

发布时间：2018-11-06 21:17

【摘要】：摘要：无轴承开关磁阻电机(BSRM)兼具了磁轴承与开关磁阻电机(SRM)的特点,不但可避免传统机械轴承的缺点,还充分利用了开关磁阻电机自身的优点,因其在高速领域的应用价值得到了各国学者广泛的研究。传统结构双绕组BSRM悬浮绕组数量多,而且电机运行中,悬浮绕组要随主绕组的切换在各相间不断切换,增加了功率电路中开关器件的个数及控制的复杂性。本文提出一种新型的共悬浮绕组式BSRM绕组结构,不论几相电机,均只需要2套悬浮绕组实现径向悬浮控制。而且,电机在整个运行过程中,不需要切换悬浮绕组,功率器件个数减少为原来的三分之一,降低了系统成本和控制复杂性。首先,对提出的共悬浮绕组式BSRM的电磁特性进行了有限元计算,分析了其悬浮性能及悬浮绕组电流对旋转转矩的影响,以及磁饱和对悬浮性能及旋转转矩的影响等,证明了共悬浮绕组式无轴承开关磁阻电机在饱和情况下依然悬浮可控；与双绕组结构BSRM进行了对比分析,验证了其在悬浮与旋转方面具有同样的特性。其次,建立了共悬浮绕组式BSRM的等效磁路模型,求取了主绕组与悬浮绕组的自感及互感表达式；提出以定子极机械位置为参考考虑转子径向偏移对定转子极间气隙变化的影响,推导了定转子极间气隙长度与转子径向偏移位置、定子极位置的数学关系；采用直线磁路结合边缘椭圆形磁路的方法求取了气隙磁导；进一步推导出了径向力、静态转矩与绕组电流及转子旋转位置角之间的数学关系。与有限元仿真结果进行比较,验证了径向力及转矩数学模型的准确性。考虑转子偏心位移对定转子极间气隙磁导的影响,提出通过近似分析法求得绕组电感,从而建立了考虑转子偏心位移影响的共悬浮绕组式BSRM径向力解析模型,得到绕组电流、转子旋转位置、转子径向偏移位置与转子所受径向力的数学关系。该数学模型的计算结果与有限元仿真结果的一致性证实了该解析模型的正确性。然后,针对共悬浮绕组式BSRM径向悬浮力系统的严重非线性,提出了基于逆系统方法的径向力非线性控制方法,依据动态性能要求调节控制参数,实现了径向力控制的动态线性化,对不同动态性能指标下精确的转子径向位移控制进行仿真,验证了控制方案的有效性。最后,搭建了共悬浮绕组式BSRM实验平台,对该电机进行了悬浮旋转试验,证明了共悬浮绕组式BSRM的悬浮可控及优良性能,为其进一步深入研究奠定了基础。
[Abstract]:Abstract: the bearingless switched reluctance motor (BSRM) has the characteristics of both the magnetic bearing and the switched reluctance motor (SRM), which can not only avoid the shortcomings of the traditional mechanical bearings, but also make full use of the advantages of the switched reluctance motor itself. Because of its application value in the field of high-speed has been widely studied by scholars all over the world. The number of BSRM levitation windings with traditional double windings is large, and in the operation of the motor, the levitation windings have to switch between phases with the main windings, which increases the number of switching devices and the complexity of control in power circuits. In this paper, a new type of common suspension winding BSRM winding structure is proposed. No matter how many phase motors are used, only two sets of suspension windings are required to realize radial suspension control. Moreover, in the whole operation process of the motor, there is no need to switch the suspension winding, and the number of power devices is reduced to the original 1/3, which reduces the system cost and control complexity. Firstly, the electromagnetic characteristics of the proposed co-suspension winding BSRM are calculated by finite element method, and the influence of the levitation performance, the current of the suspension winding on the rotating torque, and the effect of magnetic saturation on the suspension performance and the rotating torque are analyzed. It is proved that the bearingless switched reluctance motor can still be suspended and controlled under saturation condition. Compared with BSRM with double windings, it is verified that it has the same characteristics in levitation and rotation. Secondly, the equivalent magnetic circuit model of co-suspension winding BSRM is established, and the expressions of self-inductance and mutual inductance between main winding and suspension winding are obtained. Taking the mechanical position of stator pole as reference, the influence of rotor radial offset on air gap between stator and rotor is considered, and the mathematical relationship between air gap length between stator and rotor radial offset position and stator pole position is deduced. The air-gap magnetic conductance is obtained by combining the linear magnetic circuit with the edge elliptical magnetic circuit, and the mathematical relationship between the radial force, the static torque and the winding current and the rotor rotation angle is derived. Compared with the finite element simulation results, the accuracy of the mathematical model of radial force and torque is verified. Considering the influence of rotor eccentricity displacement on the magnetic conductance of air gap between stator and rotor poles, the winding inductance is obtained by approximate analysis method, and an analytical model of BSRM radial force considering rotor eccentric displacement is established, and the winding current is obtained. The mathematical relationship between rotor rotation position, rotor radial offset position and rotor radial force. The correctness of the analytical model is verified by the agreement between the calculation results and the finite element simulation results. Then, aiming at the serious nonlinearity of BSRM radial suspension force system, a radial force nonlinear control method based on inverse system method is proposed, and the control parameters are adjusted according to the dynamic performance requirements. The dynamic linearization of radial force control is realized. The accurate radial displacement control of rotor under different dynamic performance indexes is simulated and the validity of the control scheme is verified. Finally, the co-suspension winding BSRM experimental platform is built, and the suspension rotation test of the motor is carried out, which proves the suspension controllability and excellent performance of the co-suspension winding BSRM, which lays a foundation for further research.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM352

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