【作者】 王喜莲；

【导师】 葛宝明；

【作者基本信息】 北京交通大学 ， 电气工程， 2014， 博士

【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。更多还原

【Abstract】 The Bearingless Switched Reluctance Motor (BSRM) integrates both advantages of magnetic bearings and switched reluctance motor, where the suspension windings share the same stator core as the original stator torque windings, and a suitable control strategy is used to adjust the currents in both windings in such a way that the resultant radial forces support the rotor suspending in the stators center and the produced torque drives the rotor. However, the conventional double-winding BSRM has many suspension windings, e.g. three-phase motor features6sets of suspension windings. And the suspension windings have to be switched frequently during the torque windings commutation. As a result, the power converter requires many switches, and the control method and its implementation are complex, which increases the system cost and failure rate.Sharing suspension windings BSRM is proposed in the dissertation. The proposed BSRM uses only two suspension windings independent of the phase number to implement the rotor radial suspending. Because the number of suspension windings is greatly reduced, the motor structure becomes simpler. During motor operating, there is no need to switch the suspension windings. The number of IGBTs used in the power converter is reduced a lot, when compared to those required in the double-winding BSRM. The control circuit and algorithm have both been significantly simplified. The key foundation problems of the sharing suspension windings BSRM are studied in this dissertation.Firstly, the electromagnetic field of the sharing suspension windings BSRM are calculated in detail based on the Finite-element (FE) calculation. The suspension capacity and the affection of suspension windings on static torque are analyzed. The suspending force and the torque characteristics were obtained for different rotor positions and winding currents. The magnetic suspension performances of the sharing suspension windings BSRM and the double-winding BSRM are compared. The results indicate the proposed BSRM have a good suspension and rotation performance. The saturation effect on the suspending force and the torque has been also studied. The suspension controllability is verified even though the magnetic saturation of the sharing suspension windings BSRM.The magnetic equivalent circuit method is employed to obtain the self-inductances and mutual-inductances of the motor main windings and suspension windings. The affection of rotor eccentricity on the air-gap permeances between the stator and rotor tooth poles is accurately analyzed. The mathematical relationship among the rotor radial eccentricity, the air-gap length between the stator and rotor tooth poles and the mechanical position of stator is derived. The straight flux paths are combined with the elliptical fringing flux paths to calculate the air-gap permeances.Based on the calculated air-gap permeances the windings inductances of the motor and the stored magnetic energy are obtained when the rotor is located at the central point of the stator. Then, the mathematical expressions of radial forces and torque are derived. A sharing suspension windings BSRM prototype is analyzed through using the proposed analytical model and the finite element model (FEM). The proposed mathematical model of the sharing suspension windings BSRM is verified by Finite-element analysis results.Analytic modeling of radial forces is proposed for the sharing suspension windings BSRM, where the affection of rotor eccentricity on the air-gap permeances between the stator and rotor tooth poles is taken into account. The radial force model describing the relationship between the radial force, winding currents, rotor position angle, and rotor eccentricity displacement is derived. The FEM results verify the proposed radial force model.The control scheme based on inverse-system method was proposed for the serious non-linearization system of the sharing suspension windings BSRM radial suspension force. A synthesize control scheme of easily regulating control parameters according to dynamic performance remands was designed. Dynamic linearization control of radial force was achieved. The rotor radial position simulations results which satisfy the different dynamic performance remands verify the proposed method.Finally, the experimental platform of the sharing suspension windings BSRM is built to finish the preliminary static suspension and rotation suspension experiments. The systemic study results show the suspension controllability and excellent performance. The dissertation provides the basis for further research of the sharing suspension windings BSRM.更多还原