考虑端部效应的同心笼次级直线双馈电机等效电路

Equivalent Circuit for Nested-Loop Secondary Linear Doubly-Fed Machine Considering End Effect

同心笼次级直线双馈电机相关研究十分匮乏,其端部效应特征尚不明确,亦未有能体现其端部效应的等效电路,严重制约了该类电机的进一步发展。针对上述问题,该文对同心笼次级直线双馈电机静态及动态端部效应分别进行深入分析,并建立考虑端部效应的等效电路。首先,基于短初级直线电机绕组理论,阐明静态端部效应下直接耦合的产生机理,明确直接耦合感应电动势的分布特点,推导出直接耦合作用下的等效阻抗;然后,基于电机中的电磁关系,分析电机稳态运行时同心笼的过渡过程,计算出动态端部效应修正系数;随后,基于端部效应分析结果并结合传统无刷双馈电机等效电路拓扑,建立同心笼次级直线双馈电机等效电路,推导电机推力表达式;最后,通过静态端部效应和动态端部效应的有限元仿真及实验,间接验证了分析结果的合理性。

Research on the nested-loop secondary linear doubly-fed machine(NLS-LDFM) is quite scarce. The feature of its end effect is not clear along with no appropriate equivalent circuit, which restricts the further development of this kind of machine. In view of the problem, the static and dynamic end effects of NLS-LDFM are studied separately in this paper. And the equivalent circuit considering the end effect is built. Firstly, the mechanism of direct coupling by static end effect is clarified based on the winding theory for short primary linear machine. The characteristics of induced electromotive force generated by direct coupling are analyzed and the equivalent impedance is deduced. Secondly, the transition process of nested loop during steady-state operation of NLS-LDFM is analyzed. And the dynamic end effect correction coefficient is calculated. Thirdly, the equivalent circuit of NLS-LDFM is built based on the analysis of end effect and the traditional equivalent circuit of brushless doubly-fed machine. And the expression of thrust is derived. Finally, the rationality of the analysis results is indirectly verified by the finite element simulation and experiment for static and dynamic end effect respectively.