Initial Rotor Position Detection of 12/10 Flux-switching Permanent Magnet Motors

电机转子初始位置检测的精度直接决定其启动运行时的性能。针对12/10极永磁磁通切换型电机,在验证其凸极性的基础上,采用注入脉振高频信号实现转子初始位置估计。通过对传统高频脉振正弦电压信号注入的分析,研究了基于高频方波或三角波的注入方法,再利用电流差值调制或直接信号调制方法得到位置误差信号,同时根据磁路的饱和效应,通过对d轴电流过零点时间差值的累加,实现了磁极方向辨识。分析了位置误差信号的系数与初始位置检测收敛性的关系。通过实验验证了所提方法的正确性和可行性。

Electromagnetic Performance Analysis of Flux-Switching Permanent Magnet Tubular Machine with Hybrid Cores

The performance of traditional flux switching permanent magnet tubular machine(FSPMTM)are improved by using new material and structure in this paper.The existing silicon steel sheet making for all mover cores or part of stator cores are replaced by soft magnetic composite(SMC)cores,and the lamination direction of the silicon steel sheet in stator cores have be changed.The eddy current loss of the machine with hybrid cores will be reduced greatly as the magnetic flux will not pass through the silicon steel sheet vertically.In order to reduce the influence of end effect,the unequal stator width design method is proposed.With the new design,the symmetry of the permanent magnet flux linkage has been improved greatly and the cogging force caused by the end effect has been reduced.Both 2-D and 3-D finite element methods(FEM)are applied for the quantitative analysis.

Reduction of Cogging Torque in Permanent Magnet Flux-Switching Machines

Permanent magnet flux-switching machine (PMFSM) is a relatively new structure. Available literatures mainly focused on its general design procedure and performance analysis. In this paper, Finite Element Method (FEM) is taken to ana-lyze various design techniques to reduce the cogging torque in a prototype 12/10-pole PMFSM.

Novel Switched Flux Permanent Magnet Machine Topologies

This paper overviews various switched flux permanent magnet machines and their design and performance features,with particular emphasis on machine topologies with reduced magnet usage or without using magnet,as well as with variable flux capability.

Influence of Inner/Outer Stator Pole Ratio and Relative Position on Electromagnetic Performance of Partitioned Stator Switched Flux Permanent Magnet Machines

Based on the 6-pole outer stator(armature winding-stator),the influence of inner(permanent magnet-stator)/outer stator pole ratio n(n=NIS/NOS),stator relative positions and rotor pole number combinations on electromagnetic performance of partitioned stator switched flux permanent magnet(PM)machines(PS-SFPMMs)is investigated in this paper.Since the armature windings and PMs are located in two separated stators and PMs are stationary,PS-SFPMMs have high fault tolerance capabilities.To maximize the torque performance,the PM of inner stator pole should be aligned with outer stator pole when n is odd while the iron rib of inner stator pole should be aligned with outer stator pole when n is even.No matter what n is selected,the rotor pole number NR can be any integers except the phase number and its multiples.The analysis results indicate that the optimal NR is closed to(NIS+NOS)/2 and it is odd when n is odd while it is even when n is even.Meanwhile,symmetrical phase back-EMF waveform will be obtained when the ratio of Min(NOS,NIS)to the greatest common divisor of Min(NOS,NIS)and NR is even.Based on the optimal rotor pole numbers for 6-pole outer stator with different n and corresponding optimal relative position together with same rated copper loss,the average torque is improved by 18.4%,25.1%and 25.7%respectively in PS-SFPMMs with n equal to 2,3 and 4 when compared with PS-SFPMM with n equal to 1.The analyses are validated by experiment results of the prototype machine.

Development of High Torque and High Power Density Hybrid Excitation Flux Switching Motor for Traction Drive in Hybrid Electric Vehicles

This paper presents design feasibility study and development of a new hybrid excitation flux switching motor (HEFSM) as a contender for traction drives in hybrid electric vehicles (HEVs). Initially, the motor general construction, the basic working principle and the design concept of the proposed HEFSM are outlined. Then, the initial drive performances of the proposed HEFSM are evaluated based on 2D-FEA, in which the design restrictions, specifications and target performances are similar with conventional interior permanent magnet synchronous motor (IPMSM) used in HEV. Since the initial results fail to achieve the target performances, deterministic design optimization approach is used to treat several design parameters. After several cycles of optimization, the proposed motor makes it possible to obtain the target torque and power of 333 Nm and 123 kW, respectively. In addition, due to definite advantage of robust rotor structure of HEFSM, rotor mechanical stress prediction at maximum speed of 12,400 r/min is much lower than the mechanical stress in conventional IPMSM. Finally, the maximum torque and power density of the final design HEFSM are approximately 11.41 Nm/kg and 5.55 kW/kg, respectively, which is 19.98% and 58.12% more than the torque and power density in existing IPMSM for Lexus RX400h.

Nonlinear magnetic network models for flux-switching permanent magnet machines

In this paper, firstly, a basic nonlinear magnetic network model considering iron saturations is proposed for a three-phase 12-stator-slot/10-rotor-pole flux-switching permanent magnet(FSPM) machine. This model is built under cylindrical coordinates and enables the open-circuit air-gap flux-density distributions, phase permanent magnet(PM) flux-linkage, and electromotive-force(EMF) to be predicted with acceptable accuracy. However, large discrepancies are found in the predictions of armature inductances. Then, the basic model is modified by taking into account the localized saturation effect. As a result, the electromagnetic performance can be predicted more accurately, especially for the air-gap flux-density distributions. Furthermore, two improved models are proposed by adding bypass-bridge branches in stator network, to enhance the calculating accuracy of both saturated and unsaturated armature inductances. Finally, the predicted results from the four magnetic network models are validated by both 2D finite element analysis(FEA) and experimental measurements on a machine prototype. Overall, comparisons indicate that the model with bypass-bridge branches between stator teeth and back irons exhibits best performances.

基于改进滑模观测器的无位置传感器AFFSPM电机模型预测磁链控制

为了提高轴向磁场磁通切换永磁(axial field fluxswitching permanent magnet,AFFSPM)电机无位置传感器位置检测精度,同时抑制该电机的转矩和磁链脉动,该文提出一种基于改进滑模观测器(sliding mode observer,SMO)的无位置传感器AFFSPM电机模型预测磁链控制方法。首先,基于传统滑模观测器,设计边界层可随滑模面误差自调节的反正弦饱和函数,削弱系统抖振,改善系统稳态性能;接着,将扩展卡尔曼滤波器及幅值补偿环节代替单一低通滤波器,并通过内嵌二阶广义积分器的软件锁相环估算转子位置角和速度,消除位置角补偿,提高位置观测精确度;最后,将估算的转子位置角和速度反馈到模型预测磁链控制模块,完成无位置传感器控制。该文通过理论推导、仿真与实验研究验证所提出的控制策略可有效提高AFFSPM电机无传感器控制的稳态和动态性能。

Optimal Rotor Poles and Structure for Design of Consequent Pole Permanent Magnet Flux Switching Machine

Permanent magnet flux switching machines(PMFSM)have attracted significant research interest and are considered as competent candidates when higher torque density is primary requirement.However,conventional PMFSMs uses excessive rare earth PM volumes which ultimately increases machine the machine weight and PM cost.Moreover,the PMs extended at the stator yoke results in stator leakage flux which degrades the performance.To suppress the leakage flux and diminish the PM volume,the consequent pole PMFSM(CPPMFSM)with flux bridges and barriers encompassing partitioned circumferential and radial magnetized PMs is proposed,thereby ensuring an alternate magnetic path for the working harmonics which improves the modulation effect and flux distribution.Moreover,the influence of the rotor pole number on seven different rotor structures namely,curved rotor,trapezoidal rotor,wide rotor tooth tip,wide rotor base width,rectangular segmented and eccentric rotors are investigated based on the electromagnetic performance and stress distribution.Finite element analysis(FEA)reveals that the 12S-13P CPPMFSM with a wider rotor base offers comparatively better electromagnetic performance.Compare to the conventional PMFSM,the proposed CPPMFSM reduces the PM volume which minimizes the overall machine cost and weight,suppresses the torque ripples by 16.49%,diminishes total harmonic distortion(THD)by 35.24%and decreases cogging torque by 32.88%.Furthermore,the torque and power density are enhanced by 7.028%and 7.025%respectively.

磁通切换永磁电机多目标优化

以磁通切换永磁电机为研究对象,利用有限元法建立准确可靠的仿真模型,并通过仿真验证其有效性.运用灵敏度分析方法找出关键参数,引入进化算法对电机参数进行多目标优化,以提高电机的电磁性能.研究结果显示,优化后的电机平均电磁转矩提升了22.1%,转矩波动和齿槽转矩分别降低了9.09%和56.90%.

轴向磁通切换永磁电机研究进展综述

轴向磁通切换永磁电机(ASFPM)结合了轴向磁通永磁电机与磁通切换电机的特征,凭借其轴向长度短、结构紧凑、功率高、转矩密度高、散热方便等优势,在电动汽车、电动飞机、风力发电等领域广泛应用。介绍了ASFPM电机典型拓扑结构,在电机设计与分析方法、齿槽转矩抑制技术、损耗与热性能分析与优化、控制技术、应用分析等方面对国内外研究现状及进展进行综述,并对该类电机当前的应用情况进行整理。基于ASFPM电机的研究现状,对未来的研究方向进行了探讨。

基于FSPMM的直驱型纯电动汽车驱动桥设计

以一种新型开关磁通永磁电机为动力源驱动装置,介绍了新型开关磁通永磁电机的工作原理、结构参数和设计过程,结合汽车主减速器、差速器和电机,实现电动汽车的直驱设计。利用有限元分析软件对电机的结构参数进行优化,对输出特性进行仿真,结果表明,所设计的开关磁通永磁电机具有较好的鲁棒性和较高的转矩功率密度,满足纯电动汽车的运行要求。

Quantitative Comparison of Electromagnetic Performance of Electrical Machines for HEVs/EVs

In this paper,various types of sinusoidal-fed electrical machines,i.e.induction machines(IMs),permanent magnet(PM)machines,synchronous reluctance machines,variable flux machines,wound field machines,are comprehensively reviewed in terms of basic features,merits and demerits,and compared for HEV/EV traction applications.Their latest developments are highlighted while their electromagnetic performance are quantitatively compared based on the same specification as the Prius 2010 interior PM(IPM)machine,including the torque/power-speed characteristics,power factor,efficiency map,and drive cycle based overall efficiency.It is found that PM-assisted synchronous reluctance machines are the most promising alternatives to IPM machines with lower cost and potentially higher overall efficiency.Although IMs are cheaper and have better overload capability,they exhibit lower efficiency and power factor.Other electrical machines,such as synchronous reluctance machines,wound field machines,as well as many other newly developed machines,are currently less attractive due to lower torque density and efficiency.

磁通切换永磁同步电机宽调速运行分析及测试

磁通切换永磁同步电机以其简单的结构、低畸变率正弦性输出波形以及较高的转矩密度等优点,在电动汽车领域有着广泛应用,其运行特性由不同控制策略决定。针对传统磁通切换永磁同步电机运行范围较窄的不足,提出相应的最大转矩电流比和q轴弱磁控制策略。首先,分析磁通切换永磁同步电机运行工作机理及特点,建立相应的以定、转子为坐标系的数学模型。其次,根据电机不同运行区域工作特点对其性能进行仿真,计算结果显示可实现电机在高效运行的同时拓宽其运行范围。最后,基于一台1 kW样机搭建控制测试系统。转矩和功率输出测试结果显示,结果表明所提出的弱磁控制策略拓宽电机运行范围,正确性和有效性得到验证。

考虑交叉耦合效应的混合励磁开关磁链电机转子位置估计

针对使用高频电压注入法估计混合励磁开关磁链永磁(HESFPM)电机转子位置时,由于直轴和交轴之间的交叉耦合效应使得转子位置估计精确度降低的问题,提出了一种对交叉耦合效应进行角度补偿的HESFPM电机励磁绕组高频电压注入位置估计方法。通过电枢绕组α、β轴高频电流响应估计转子位置,分析了交叉耦合效应对所提出的高频电压注入位置估计精确度的影响,通过离线方法测量出该效应导致的交叉饱和角,并进行无位置传感器控制在线角度补偿。最后,通过12槽10极HESFPM样机进行实验验证,实验结果表明电机运行在不同转速、负载工况下,所提方法能够有效减小位置估计直流偏置误差,具有良好动态跟随性能。

集成压缩机用双定子磁通切换电机的设计及优化

针对轴流压缩机系统体积大、冷却难的问题,基于6/4双定子磁通切换永磁电机,提出一种新型集成压缩机用磁通切换永磁电机(FSPMM)。首先,推导了考虑转子斜极影响的齿槽转矩解析表达,建立了气体流量轨迹模型。其次,设计E型槽FSPMM和C型槽FSPMM结构并建立有限元仿真模型,对其磁密分布、反电动势、齿槽转矩、电磁转矩及波动等电磁特性进行了计算和对比分析,结果表明E型槽FSPMM的电磁性能明显优于C型槽FSPMM的电磁性能。最后,综合考虑电磁性能和流体影响,对E型槽FSPMM的转子结构进行了优化,优化后的6/4双E型槽FSPMM的转矩波动下降了15.25%,出口流速提高到113.27 m/s,适用于多级轴流压缩机系统。

真空干泵用磁通切换永磁同步电机温度场仿真分析

针对真空干泵驱动用电机在极端真空环境下工作时发热严重的问题,以一台4.5 kW磁通切换永磁同步电机(FSPMSM)为研究对象,分析了其冷却结构,并进行了温度场仿真计算。通过有限元软件建立FSPMSM三维温度场仿真计算模型,设定边界条件和热源激励,得到电机内部各部件的温度分布情况,并分析了水道截面直径、水道圈数对电机温度变化的影响。与一台技术要求相同的永磁同步电机(PMSM)在同等冷却条件下进行温度场对比分析,结果表明本电机设计合理。相比于真空干泵常用的传统PMSM,本电机能更好地减少损耗并降低温升,为开发真空干泵用FSPMSM新产品提供了一定的参考。

模块化多单元磁通切换电机设计与特性分析

该文提出一种具有高转矩密度、低转矩脉动的新型模块化多单元磁通切换(modularelementaryfluxswitching permanentmagnet,ME-FSPM)电机结构,研究槽极配合对电磁特性的影响。基于气隙磁场调制原理,从永磁磁场调制的角度阐明ME-FSPM电机气隙磁导调制系数对永磁磁密调制谐波影响规律。由于轴向模块配合与集成环形绕组拓扑,ME-FSPM电机不同槽极配合下具有高绕组因数特征,进而针对性的定义气隙磁导调制系数是决定永磁磁链基波幅值的关键参数。依据气隙磁导调制系数模型,揭示电负荷恒定下转子极数与电磁转矩变化规律。基于气隙磁密分布规律,分析模块配合下齿槽转矩抑制原理,依据槽极配合选择实现齿槽转矩基波抵消以及输出转矩提升,提出ME-FSPM电机槽极配合选择方法。最后,在6槽ME-FSPM电机结构下,选择6槽/7极和6槽/8极结构具有良好的转矩特性,并通过仿真与实验验证理论方法的合理性与有效性。

高频电流注入单绕组无轴承磁通切换电机悬停及启动过程的无径向位移传感器控制

无轴承电机在悬停及启动过程始终需要保持稳定悬浮,准确获取转子径向位移信息是控制转子稳定悬浮的关键,传感器的使用易受环境影响,降低系统可靠性,并且增加系统成本。针对电机悬停及启动过程,提出一种基于高频电流注入的无径向位移传感器控制方法。首先,基于电机电感数学模型,建立当转矩平面注入高频旋转电流信号后,空间对称绕组中有效高频偏差电势幅值与转子径向位移的关系;接着,利用线性正弦跟踪器提取有效高频偏差电势幅值;然后,基于上述电势幅值与转子径向位移关系,构建转子径向位移观测器;最后,将观测位移与自抗扰控制策略相结合,构建高性能的无径向位移传感器控制策略。理论分析与实验结果验证所提方法的有效性。

用于双边磁通切换直线电机涡流损耗抑制的永磁体结构优化设计

为降低双边磁通切换直线电机永磁体的涡流损耗,以一台6槽17极双边磁通切换直线电机为研究对象,对其永磁体的结构进行优化设计。首先对稳态工况下永磁体涡流损耗的分布特点进行分析,其次通过理论推导和仿真计算,获得了横向对称分割3块的永磁体结构,最后提出了新型半Halbach永磁体阵列结构,并利用曲线拟合、黄金分割法和抛物线插值法获得了永磁体最优充磁角度。仿真结果表明,所提出的永磁体结构能够在不影响DLFSPM平均电磁推力的前提下,可有效抑制永磁体涡流损耗。