【目的】本文针对分数槽集中绕组(FSCW)定子轴向磁通同步电机存在齿槽转矩会导致振动噪音,降低控制精度与运行平稳性的问题,利用虚位移法分析其产生原因并推导其近似表达式,为电机设计、制造、优化提供理论依据。【方法】首先分析了FSCW的基本理论,介绍贯穿式FSCW定子轴向磁通双转子同步电机(AF-DR-TS-FSCW-SG)的结构特点及其主磁通耦合原理。然后采用虚位移法分析该类电机齿槽转矩产生机理,并结合磁路法推导齿槽转矩表达式,得到其近似数学模型。同时本文还提出一种针对轴向磁通双转子同步电机的二维有限元仿真模型,并通过空载试验验证该模型的准确性。最后通过齿槽转矩数学模型得到的齿槽转矩主导谐波幅值与二维有限元仿真结果进行对比分析。【结果】结果表明,在一号转子单独激励、二号转子单独激励、两转子同时激励三种工况下的二维有限元仿真结果与试验结果在空载电压幅值上的相对误差依次为4.02%、16.84%与10.73%,波形变化趋势保持一致。同时一号转子单独激励与二号转子单独激励工况下二维有限元仿真的齿槽转矩与通过虚位移法计算结果在齿槽转矩主导谐波上的相对误差为13.86%与13.57%。【结论】本文所提出的FSCW定子轴向磁通同步电机二维有限元仿真模型能较准确地反映电机实际性能,同时利用虚位移法推导的齿槽转矩数学模型具有较高的准确性。

[Objective] This paper addresses the cogging torque inherent in fractional-slot concentrated winding (FSCW) stator axial-flux dual-rotor synchronous generator, which can induce vibration and acoustic noise, degrade control accuracy and operational smoothness. The virtual displacement method is employed to analyze the underlying mechanism of cogging torque generation and to derive its approximate analytical expression, thereby providing a theoretical basis for generator design, manufacturing, and optimization. [Methods] First, the fundamental theory of FSCW was reviewed, and the structural characteristics and coupling principle of an electrically excited through-FSCW-stator axial-flux dual-rotor synchronous generator (AF-DR-TS-FSCW-SG) were introduced. Subsequently, the cogging torque generation mechanism of this class of generators was analyzed using the virtual displacement method, and an analytical expression for cogging torque was derived based on the magnetomotive force-permeance method, yielding an approximate mathematical model. In addition, a two-dimensional finite element modeling approach tailored for axial-flux dual-rotor synchronous machines was proposed, and its accuracy was validated through no-load electromagnetic characteristic experiments. Finally, the dominant subharmonic amplitudes of cogging torque obtained from the analytical model were compared with those derived from two-dimensional finite element simulations. [Results] The results indicated that the relative errors of the no-load back electromotive force (EMF) amplitude between the two-dimensional finite element analysis (2-D FEA) results and the experimental measurements under three operating conditions—namely, excitation of rotor 1 alone, excitation of rotor 2 alone, and simultaneous excitation of both rotors—were 4.02%, 16.84%, and 10.73%, respectively. Despite the amplitude discrepancies, the waveform variation trends showed good agreement among all cases. Meanwhile, for the operating conditions with rotor 1 alone and rotor 2 alone excited, the relative errors of the dominant harmonic component of the cogging torque between the 2-D FEA results and the analytical results obtained by the virtual displacement method were 13.86% and 13.57%, respectively. [Conclusion] The proposed two-dimensional finite element modeling approach for the FSCW-stator axial-flux dual-rotor synchronous generator in this paper can accurately reflect the actual performance of the generator. In addition, the cogging torque mathematical model derived based on the virtual displacement method exhibits high accuracy.

中国博士后科学基金面上项目(2017M621086);江苏省配电网智能技术与装备协同创新中心开放基金项目(XTCX202405)