基于相位分析的双定子低速大转矩永磁同步电动机转矩脉动研究

针对双定子低速大转矩永磁同步电动机的转矩脉动问题,该文基于相位分析研究了内外定子槽数配合以及内外定子相对位置对双定子永磁同步电动机转矩脉动的影响。利用叠加原理,将整个电机分为两个部分,即内、外两个电机分开研究转矩脉动。在内外定子槽数不同的情况下,通过分析反电动势,发现谐波的绕组系数正负性会对内外电机反电动势的相位产生影响,基于此,对内外电机反电动势相位进行了预测,并进一步预测内外电机各自的纹波转矩相位,分析了内外电机纹波转矩相位对整个电机纹波转矩的影响。在内外定子槽数相同时,基于电动势和电流的转矩模型,论证了内外定子A相轴线的相对位置会影响整个电机的转矩脉动大小。通过有限元仿真,验证了以上的理论预测。

转子偏心对低速大转矩永磁同步电机损耗与发热的影响

为了研究转子偏心对损耗与发热的影响,以一台400 kW、20 r/min的低速大转矩永磁同步电机为对象,分析并建立了其转子偏心时的二维非线性时变电磁场和三维各向异性温度场模型,并通过有限元分析了转子偏心对该电机电磁性能及损耗、发热的影响。结果表明,随着转子偏心率的增加,反电动势及定子铁耗变化不大,但气隙磁密谐波畸变率、电枢电流、电磁转矩、齿槽转矩、定子铜耗、转子损耗及电机发热明显增加,转子偏心反向侧的局部温升变大;采用强迫风冷代替自然风冷后,可有效降低最高温度并使温升分布更加均匀。

同步磁阻电机分析与设计(连载之十二) 永磁辅助同步磁阻电机的设计研究

针对两层磁障的同步磁阻电机,分析磁障厚度比例对磁阻转矩的影响。进而在优化的同步磁阻电机中间磁障中插入永磁体形成永磁辅助同步磁阻电机,讨论此类永磁辅助同步磁阻电机的齿槽定位力矩、永磁转矩、磁阻转矩和抗退磁性能。最后对比了同步磁阻电机和永磁辅助同步磁阻电机的转矩特性以及调速特性。

一种永磁同步电机无模型高阶滑模控制算法

针对城市轨道交通高转矩永磁同步牵引电机因参数摄动和未知扰动等不确定因素造成控制性能下降的现象,提出一种基于扩展非奇异终端滑模扰动观测器的转速环新型无模型非奇异快速终端滑模控制方法。首先,依据永磁同步牵引电机在参数摄动和未知扰动下的数学模型,使用转速环的输入输出建立新型超局部模型。其次,基于新型超局部模型设计转速环的无模型非奇异快速终端滑模控制器;同时结合高阶滑模和非奇异终端滑模设计观测器来实时精准估计新型超局部模型的未知部分,通过对控制器进行前馈补偿,增强了系统的鲁棒性,提高了转速的控制精度,并减少了系统抖振。最后,通过与PI控制、无模型滑模控制进行仿真和实验综合比较,验证了所提出的控制算法对电机参数摄动和未知扰动具有较强的容错性和抗干扰性,能降低对电机精准数学模型的依赖。

永磁同步电机转子磁钢拓扑结构与运行工况匹配性分析

基于永磁同步电机应用较广的"一"字型、"V"字型磁钢拓扑结构,在制造材料消耗量、供电方式、功率输出参数、机械与散热结构一致的前提下分别设计两台电机,通过对比分析两台电机额定点参数、永磁转矩与磁阻转矩占比、弱磁调速能力,总结出两种磁钢拓扑结构各自所适用的运行工况。

FYT300汽流纺配套电机改型设计

原与汽流纺机配套的KX132电机现由FYT300永磁同步电动机替代。这是一种特殊的切向转子结构永磁电机,文章对它的附加转矩和牵入转矩等性能指标作详细的探讨。替代后电机的效率和功率因素大幅提高,并提高了纺纱的产品质量和生产效率。

Cogging Torque Reduction in Axial Flux PMSM with Different Permanent Magnet Combination

With the increasing requirement for the mechanical vibration and acoustic noise of the permanent magnet synchronous motor(PMSM)drive system,the demand for cogging torque reduction of PMSM has been considerably increased.To solve the problem of oversized cogging torque of axial flux PMSM,a rotor topology with hybrid permanent magnet is proposed to weaken the cogging torque.Firstly,the expression of the cogging torque of the axial flux motor is derived,and the influence of the pole-arc ratio of the permanent magnet on the cogging torque is analyzed.Secondly,the rotor structure with hybrid permanent magnet is adopted to reduce the cogging torque.According to the analytical analysis,the constraints of the size and pole-arc ratio between the hybrid permanent magnets are obtained,and the two permanent magnets related to the minimum cogging torque are determined.And the analysis results are verified by the finite element simulation.Furthermore,the motor performance with and without the hybrid permanent magnet is compared with each other.Finally,the cogging torque is significantly reduced by adopting a rotor structure with hybrid permanent magnets.

Influence of Rotor Structure and Number of Phases on Torque and Flux Weakening Characteristics of V-Shape Interior PM Electrical Machine

This paper investigates the influence of the rotor structure on torque and flux weakening region of V-shape IPM （interior permanent magnet） machine from TOYOTA PRIUS type. More specifically, always keeping the same magnet volume, the effect of the open angle between the two magnet segments of each V-shape pole on the machine performance is studied. Moreover, in order to examine the impact of phase number on the machine characteristics, PRIUS structure is transformed into 5-phase machine of the same type and dimensions. As well, an optimization procedure is carried out to determine the optimal open angle according to main characteristics. The previous investigation is done by using a free FEM （finite elements methods） program coupled with another optimization program. Using this obtained methodology, the study analyzes for 3-phase and 5-phase machine the average and pulsation of torque, cogging torque, phase EMF （electro-motive force）, constant power operating capability.

A New Scheme to Direct Torque Control of Interior Permanent Magnet Synchronous Machine Drives for Constant Inverter Switching Frequency and Low Torque Ripple

DTC （direct torque control） can produce quick and robust response, but it has the problems of large torque ripples and inconstant inverter switching frequency. This paper introduces a modified direct torque control based on the SVM （space vector modulation） for IPMSM （interior permanent magnet synchronous motor） drive. Two PI （proportional-integral） controllers regulate the flux and torque, respectively, and the inverter is controlled by the SVM technique in the proposed DTC system. Simulation results show that the performance of the proposed DTC system has been improved with respect to the conventional DTC. The DTC system can effectively reduce the flux and torque ripples.

Torque characteristics in a large permanent magnet synchronous generator with stator radial ventilating air ducts

In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet shape optimization was used first to improve the torque characteristics using two-dimensional finite element analysis（FEA） in a permanent magnet synchronous generator with a common stator. The rotor step skewing technique was then employed to suppress the impacts of mechanical tolerances and defects, which further improved the torque quality of the machine. Comprehensive three-dimensional FEA was used to evaluate accurately the overall effects of stator radial ventilating air ducts and rotor step skewing on torque features. The influences of the radial ventilating ducts in the stator on torque characteristics, such as torque pulsation and average torque in the machine with and without rotor step skewing techniques, were comprehensively investigated using three-dimensional FEA. The results showed that stator radial ventilating air ducts could not only reduce the average torque but also increase the torque ripple in the machine. Furthermore, the torque ripple of the machine under certain load conditions may even be increased by rotor step skewing despite a reduction in cogging torque.