Characteristics of a permanent magnet type bearingless motor

Super high-speed and high-power electric machines are required for turbomolecular pumps and spindle drives. High rotational speed and high power drives can be achieved with bearingless motors. In this paper, a bearingless motor with the principles of permanent magnet type synchronous motors is proposed. High power factor and high efficiency can be expected in permanent magnet type bearingless motors. The proposed bearingless motor is a 4 pole permanent magnet synchronous motor, in which additional 2-pole windings are wound together with 4-pole motor windings in stator slots. With currents of 2-pole windings, radial magnetic forces are produced to support a rotor shaft. Principles of radial force production of surface-mounted permanent magnet bearingless motors are analyzed mathematically. It was found that radial forces are efficiently produced by employing thin permanent magnets on the surface of rotor iron core. A test machine was built in order to measure inductance functions as well as relationships between voltages and currents     

无轴承永磁同步电机有限元分析

无轴承永磁电机径向悬浮力与电机绕组结构、永磁体厚度及悬浮力绕组中电流等存在着复杂关系，研究这些关系对电机优化设计具有重要参考价值。该文在介绍了无轴承永磁同步电机径向悬浮力产生原理基础上，推导了径向悬浮力数学模型。用有限元分析和计算方法，讨论了无轴承永磁同步电机在定子绕组相应等效电流作用下，改变径向悬浮力绕组中的电流，电机气隙磁路分布状况；在电机气隙不变，改变永磁体厚度，计算和分析了径向悬浮力与永磁体厚度之间的关系；在电机转矩绕组极对数pM=2不变的情况下，对径向悬浮力绕组采用一对极pB=1和三对极pB=2方式绕制，计算和比较产生的径向悬浮力和麦克斯韦力大小。对pM=2，pB=3的实验样机，在静态悬浮状态下，测试了径向悬浮力和径向悬浮力绕组电流之间的关系，实验结论验证了ANSYS软件计算结果的正确性。     

基于退磁限制的无轴承永磁同步电机性能参数分析

无轴承永磁同步电机磁场中不仅存在转矩绕组电流产生的磁通,而且存在径向悬浮力绕组电流产生的磁通,这两种磁场会导致永磁体退磁。设计永磁体参数需考虑产生最为有效径向悬浮力、电磁转矩和避免永磁体退磁三者之间的关系。论文分析了转矩绕组电流产生的磁通和径向力绕组电流产生的磁通共同作用下,转子表面永磁体容易引起退磁的关键区域;在电机气隙不变情况下,分析得出了保证产生最为有效的径向力时最佳永磁体厚度;基于永磁体退磁限制,采用有限元分析计算,针对论文中设计的永磁体厚度及气隙长度,得出了无轴承永磁同步电机最大转矩电流、径向悬浮力电流和产生的最大径向悬浮力。     

无轴承永磁同步电动机永磁体参数优化设计

介绍了无轴承永磁同步电动机径向悬浮力产生原理。通过对比各种永磁体材料的性能和不同转子磁路结构特点,确定采用钕铁硼稀土永磁体,选择转子表面凸装式结构;从理论上分析了径向悬浮力与永磁体厚度、径向悬浮力绕组电流之间的关系;采用有限元方法,在考虑磁路饱和及非线性情况下,对实验样机径向悬浮力进行了计算和分析。研究结果对无轴承永磁同步电动机如何获得最大径向悬浮力以及电动机的优化设计具有参考价值。     

交替极永磁无轴承电机的直接悬浮力控制

通过借鉴永磁同步电机直接转矩控制(PMSM-DTC)的思想,将直接转矩控制的理论和方法应用到永磁型无轴承电机磁悬浮力的控制上去,提出了一种新颖的基于空间矢量脉宽调制(SVPWM)方法的直接悬浮力控制算法,并在一台交替极无轴承永磁电机上进行了实验验证,结果表明该控制思想的正确性和有效性。     

无轴承永磁同步电机的转子磁场定向控制研究

无轴承永磁同步电机由于功率密度大、转矩脉动低等优良特性受到了高度重视。文中针对一类表面贴装式无轴承永磁同步电机，详细推导出径向悬浮力表达式，建立了准确的数学模型。针对电磁转矩和径向悬浮力之间耦合的特点，采用了基于转子磁场定向的控制策略来实现这类无轴承永磁同步电机的非线性解耦控制。实验证明了该控制算法的有效性。该控制算法对插入式转子结构和内装式转子结构的无轴承永磁同步电机的控制系统设计具有一定的借鉴作用。     

无轴承永磁同步电机径向悬浮力动态解耦控制

针对无轴承永磁同步电机径向悬浮力之间存在的非线性、强耦合问题,提出基于神经网络逆系统方法的无轴承永磁同步电机径向悬浮力动态解耦控制策略.在分析无轴承永磁同步电机的工作原理和径向悬浮力产生机理的基础上,建立径向悬浮力的数学模型,并对该数学模型进行可逆性分析,证明此系统可逆.利用神经网络逆系统方法,将原来的非线性强耦合的多...     

无轴承永磁同步电动机的原理及实现

无轴承永磁同步电动机是将无轴承技术运用到永磁同步电动机上的新型无轴承电动机.本文阐述了永磁同步电动机无轴承技术的工作原理,设计和实现了该电动机基于LF2407A数字控制的硬件实验平台和软件系统.通过对整个无轴承永磁同步电动机系统的实验调试,成功实现了无轴承永磁同步电动机转轴的稳定悬浮.     

永磁无刷直流电动机场路耦合运动时步有限元分析

提出一种适用于永磁无刷直流电动机的场路耦合运动时步有限元分析方法，解决了电机在非正弦供电时的场路耦合分析问题。电路中考虑了开关元件换流重叠过程和绕组中点的电位波动。给出了控制电路与电磁场方程耦合的时步有限元单元分析方法，采用改进的有限元运动边界处理方法--插值运动边界法解决转子运动问题。应用上述模型对1台无刷直流电动机的进行分析，计算结果和样机的实测波形吻合。该方法也适用于其他非正弦供电电机的场路耦合有限元分析。     

无轴承永磁同步电动机设计与有限元分析

在分析无轴承永磁同步电动机径向力产生原理的基础上，推导出径向力数学模型；采用有限元法对设计的样机进行分析，计算样机的径向力与转矩。研究结果表明：采用有限元法设计不仅能对参数进行优化选择，而且缩短了电动机设计周期。     

Analysis of Winding Forms for Bearingless Flux-Switching PM Motor with U-core Stator Laminations

Due to low-cost and magnet-free rotor structure, bearingless flux-switching permanent magnet motors (BFSPMs) are more applicable to high-temperature and/or disposable applications. A BFSPM with U-core stator laminations is investigated in this paper. First, the operational principle is analyzed in accordance with the influence of winding connection manners on torque and radial forces, and then the basic winding arrangement for torque windings and radial force windings is determined. The mathematical models of torque and radial forces are derived based on the basic winding arrangement. Followed by that, a method to select winding terminal connection manners is proposed by taking into account control scheme and power inverter topologies. A promising terminal connection is found from three possible candidates and a detailed current model for torque and radial force control are given for the promising winding forms. Finally, relevant electromagnetic properties of the motor are verified and analyzed by finite element analysis.     

矩形与面包形磁钢永磁同步电机噪声对比分析

为了对比分析矩形磁钢和面包形磁钢永磁同步电机运行时产生的0阶振动噪声,从理论上对电机的径向电磁力波进行推导,对力波的的磁密来源进行了分析,讨论了两种不同磁钢形状的永磁同步电机的0阶振动噪声。基于Workbench仿真平台,对这两种不同磁钢形状的36槽24极永磁同步电机进行仿真分析,得到两种电机的0阶6倍频力波的组成和0阶径向电磁力波的傅里叶分析结果;对电机定子的结构分别进行有限元建模和解析计算,得出电机结构的固有模态;通过解析计算的方法,得到电机定子表面的0阶电磁力振动位移频谱图;最后,通过计算电机的声辐射效率,对电机外部声场进行快速建模,计算出电机0阶电磁力声功率级频谱图。研究表明:面包形磁钢永磁同步电机的振动噪声要远小于矩形磁钢永磁同步电机的振动噪声。     

无轴承永磁同步电机控制系统设计与仿真

无轴承永磁同步电机是自身具有磁悬浮轴承功能的新型特种电机，是一个复杂的强耦合的非线性系统，建立无轴承永磁同步电机径向悬浮力和电机数学模型，是设计无轴承永磁同步电机控制系统的前提，实现其径向悬浮力和电磁转矩之间的解耦控制是电机稳定运行的基本条件。该文在介绍无轴承永磁同步电机径向悬浮力产生原理的基础上，推导了径向悬浮力和电机数学模型，采用基于转子磁场定向控制策略设计了无轴承永磁同步电机矢量控制系统，利用Matlab的Simulink工具箱构建了矢量控制系统，对无轴承永磁同步电机的转速、转矩及转子起浮性能进行了仿真。仿真结果表明控制系统不仅可以实现转子稳定悬浮，而且电机具有良好的动态性能。     

无轴承永磁同步电机参数优化设计

无轴承永磁同步电机径向悬浮力与永磁体厚度和气隙长度有关,研究径向悬浮力与这些参数之间的关系对电机优化设计具有重要意义。该文在介绍径向悬浮力产生机理的基础上,针对转矩绕组极对数PM=1,悬浮力绕组极对数PB=2的样机,从理论上分析了径向悬浮力与永磁体厚度和气隙长度之间的关系,并采用有限元方法(FEM)对此关系进行了验证。研究结果对于电机的优化设计具有参考价值。     

Radial Force Analytic Modeling for a Novel Bearingless Switched Reluctance Motor When Considering Rotor Eccentricity

Abstract—Analytic modeling of radial forces is proposed for the novel bearingless switched reluctance motor, where the rotor eccentricity is taken into account. The novel bearingless switched reluctance motor's model is never disclosed, even though there are many advantages, such as fewer suspension windings and simpler control circuit and algorithm, when compared to the conventional bearingless switched reluctance motor. The analytic model of radial forces is very important to achieve this new bearingless switched reluctance motor's suspension control. The rotor eccentricity is a key cause to affect the radial forces. This article calculates the air-gap permeances through considering rotor eccentricity. The self-inductance and mutual-inductance expressions of the motor torque windings and the suspension windings are derived by using the magnetic equivalent circuit method. The derived radial force model discloses the effects of winding currents, rotor position angle, and rotor eccentricity displacement. The finite-element analysis based results verify the built model.     

不同绕组连接方式下的六相永磁同步电动机MT容错控制

多自由度使多相电机具备了优异的容错能力。本文针对单中性点、双中性点及开端绕组结构的六相永磁同步电机,以缺相容错运行时输出转矩最大为目标,提出一种适用于不同绕组结构电机的容错电流计算通用表达式。通过对六相永磁同步电机缺一相故障状态下的自由度进行分析,计算了不同定子绕组结构下的容错电流,并给出相应的控制方法。对比三种不同绕组结构电机容错运行时的带载能力,开端绕组结构的六相永磁同步电机缺相容错运行时输出转矩最大。利用Matlab/Simulink建立了六相永磁同步电机模型及其控制系统,验证了计算结果的有效性。     

Analysis of inductance characteristics for a bearingless permanent magnet synchronous motor

In this paper, the inductance characteristics of a 2-pole surface-mounted bearingless permanent magnet synchronous motor (BPMSM) with 4-pole suspension force windings are investigated based on theoretical analysis and experimental investigation. Firstly, the winding configuration and operation principle of the BPMSM are presented. Secondly, the static and incremental inductances are defined. Then, based on the finite element (FE) analysis method, the static inductances of torque windings and suspension force windings in stator static coordinate reference are researched. In addition, the d- and q-axes static inductances in rotor revolving coordinate reference are obtained by 3/2 Transformation. Furthermore, taking the torque windings as an example, the incremental inductance of torque windings is studied, and the validity of the theory is confirmed by comparing the static and incremental inductances. Finally, the experimental study is carried out to verify the discussed numerical analysis. The results are helpful to measure parameters and build the mathematic model of BPMSMs, and lay a foundation for the further research on BPMSMs.     

无轴承永磁同步电动机的独立控制研究

传统无轴承永磁同步电机的控制方案由于悬浮绕组的控制必须获得转矩绕组传递的气隙磁场幅值和相位信息，使得转矩绕组和悬浮绕组的控制策略受到相互制约。文中采用传统的电压-电流模型方法辨识出所需的转矩绕组气隙磁链，使电机的电磁转矩和悬浮力控制实现独立控制，从而极大的提高了无轴承永磁同步电动机在超高速领域的实用性。实验结果表明该独立控制方法能较好地满足电机径向悬浮的稳、动态性能要求。     

Sensorless vector control of PMSM with non-sinusoidal flux using observer based on FEM

Back electromotive force method has been widely used in the position and speed sensorless control of permanent magnet synchronous motors. In this method, it is supposed that the back electromotive forces induced on the stator windings by the rotor permanent magnets are sinusoidal. This assumption causes errors in the estimation of speed and position. In this paper, an observer using the stator winding linkage flux model obtained by using finite element method for position and speed sensorless field-oriented control of permanent magnet motor is proposed. The validity of the proposed method is demonstrated using DS 1104.     

无轴承永磁同步电机原理及研究发展趋势

无轴承永磁同步电机是采用了无轴承技术的高性能永磁同步电机,同时具备永磁同步电机的优良特性与磁悬浮轴承的优点。阐述了转矩绕组极对数为2,悬浮力绕组极对数为3的无轴承永磁同步电机悬浮力产生原理,总结了目前国际国内无轴承永磁同步电机在结构方面与控制策略方面的研究成果,为无轴承永磁同步电机结构改进与控制优化提供重要参考。分析了无轴承永磁同步电机研究发展趋势,为无轴承永磁同步电机进一步研究指明方向。