Hybrid Excited Permanent Magnet Machines for Electric and Hybrid Electric Vehicles

This paper reviews various hybrid excited(HE)machines from the perspective of location of PM and DC excitation,series/parallel connection of PM and DC excited magnetic fields,and 2D/3D magnetic fields,respectively.The advantages as well as drawbacks of each category are analyzed.Since an additional control degree,i.e.DC excitation,is introduced in the HE machine,the flux weakening control strategies are more complex.The flux weakening performance as well as efficiency are compared with different control strategies.Then,the potential to mitigate the risk of uncontrolled overvoltage fault at high speed operation is highlighted by controlling the field excitation.Since additional DC coils are usually required for HE machines compared with pure PM excitation,the spatial confliction inevitably results in electromagnetic performance reduction.Finally,the technique to integrate the field and armature windings with open-winding drive circuit is introduced,and novel HE machines without a DC coil are summarized.

Cooling System Design Optimization of an Enclosed PM Traction Motor for Subway Propulsion Systems

This paper presents the design optimization of a self-circulated ventilation system for an enclosed permanent magnet(PM)traction motor utilized in the propulsion systems for subway trains.In order to analyze accurately the machine's inherent cooling capacity when the train is running,the ambient airflow and the related heat transfer coefficient(HTC)are numerically investigated considering synchronously the bogie installation structure.The machine is preliminary cooled with air ducts set on the motor shell,and the fluidic-thermal field distributions with only the shell air duct cooling are numerically calculated.During simulations,the HTC obtained in the former steps is applied to the external surface of the machine to model the inherent cooling characteristic caused by the train movement.To reduce the temperature rise and thus guarantee the motor's working reliability,an internal self-circulated air cooling system is proposed according to the machine temperature distribution.The air enclosed in the end-caps is driven by the blades mounted on both sides of the rotor core and forms two air circuits to bring the excessive power losses generated in the heating components to cool regions.The fluid flow and temperature rise distributions of the cooling system's structural parameters are further improved by the Taguchi method in order to confirm the efficacy of the internal air cooling system.

永磁电机系统中冗余结构逆变器的可靠性分析对比研究

基于马尔可夫模型和可靠性框图模型,对永磁电机系统中并联冗余和备用冗余两种结构的逆变器在零件层面和系统层面进行可靠性分析,得到这两种结构逆变器的可靠性函数和平均无故障时间函数。首先,通过对比来确定判断何种冗余结构具有更高可靠性的边界条件函数。其次,分析边界条件函数随各参数的变化情况以及对冗余结构可靠性的影响,包括环境温度、电流、热阻抗和容错处理机制的成功率。然后,建立N相冗余逆变器的可靠性函数,并给出高可靠冗余结构中并联支路数和备用支路数量的确定方法。最后,以三相永磁电机逆变器为例,通过仿真和实验验证边界条件函数的准确性。

V型交替极永磁同步电机气隙磁场调制效应研究

与传统V型永磁(V-shaped permanent magnet,VPM)结构相邻N和S极永磁体形成一对极磁场不同,V型交替极永磁(V-shaped consequent-pole permanent magnet,VCPM)结构永磁体与相邻铁心形成一对极磁场。为进一步探究VPM和VCPM电机磁场分布的不同带来的转矩性能差异,首先通过麦克斯韦应力张量法确认,并量化分析VPM和VCPM电机气隙磁密各次谐波转矩贡献,揭示两种电机主谐波与调制谐波转矩贡献的差异性,进而阐明VCPM电机转矩提升的根本原因在于其显著增加的调制谐波贡献的转矩分量。然后,研究关键结构参数对VCPM电机气隙磁场调制效应的影响规律。最后,加工一台VCPM样机并开展试验研究,验证理论分析和有限元仿真结果的可靠性。

PMSM驱动系统位置传感器偏转故障的诊断与容错

电动汽车驱动用的永磁同步电机系统,由于经常工作在振动等恶劣环境,其传感器容易出现偏转而造成故障。针对这个问题提出了一种在线监测传感器偏转故障和实时容错的方法。该方法根据电机驱动系统输入功率与输出功率之间的关系选取故障特征量,并通过此故障特征量来检测转角误差,同时利用转角与故障特征量之间的关系对误差角度进行估算,以使电机容错运行。对该方法进行了仿真验证,并证明了该方法的有效性和可行性。

Improved Sensorless Operation of Interior PM BLAC Motor Drives with Reduced-Order EKF

It is a challenge to realise an EKF-based sensorless controller for an Interior Permanent Magnet （IPM） brushless ac motor drive due to the influence of nomlinearities and rotor saliency. An improved reduced-order EKF method is presented, reducing the rotor position estimation error of an IPM motor, as evident in [1] due to the neglect of saliency. The effectiveness of the proposed method is verified experimentally.

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.

Characteristic investigation of permanent magnet actuator for vacuum contactors operating with an intrinsically safe low voltage

This paper reports a new application of permanent magnet actuator for vacuum contactors.A novel permanent magnet(PM) actuator to drive a vacuum contactor with intrinsically safe and low supply voltage is proposed.PM is mounted on the static iron of the contactor to enhance its holding force and reliability.While only one coil is used to break the vacuum contactor,two series coils are deployed to yield a high magnetomotive force to realize the making operation.The electrical circuit equation,mechanical equation and magnetic field are all coupled in the simulation.A prototype is manufactured and tested to validate and showcase the performance of the contactor which is equipped with the proposed PM actuator.

基于Cuk变换器的永磁记忆电机调磁控制

针对永磁记忆电机(permanent magnet memory motor,PM-MM)调磁控制中存在的电压限制问题,提出一种基于Cuk变换器的控制策略。首先分析随着PM-MM调磁速度的增加,电压限制问题对系统稳定性的影响;在此基础上利用Cuk变换器的原理,结合PM-MM的数学模型,针对调磁过程中的电压限制问题,提出了一种基于Cuk变换器的PM-MM调磁控制策略,并以一台20 kW的PM-MM为被控对象进行仿真研究。结果表明:所提策略能有效补偿电机调磁过程中所需的电压,大幅抑制了充磁过程中的转矩及转速的波动,提高了系统的稳定性。

智能单稳态永磁接触器动作特性的联合仿真

该文提出一种智能单稳态永磁接触器的联合仿真方法。首先,针对传统电磁接触器等效电路在永磁接触器的保持及分闸过程中存在的应用缺陷,将电磁磁链与永磁磁链分开考虑,提出适用于全过程的永磁接触器等效电路模型。之后,采用永磁接触器的有限元仿真结合等效磁路来处理永磁磁场与电磁磁场的相互耦合问题,从而给出等效电路模型中各元件参数的计算方法。最后,结合分合闸控制策略及永磁接触器动态模型,构建单稳态智能永磁接触器的联合仿真方法,并通过实验验证该仿真方法的有效性。在永磁接触器的整个动态过程中,该仿真方法详细反映出电磁磁场与永磁磁场的相互影响,为基于电磁力、永磁力及弹簧反力密切配合的高性能优化控制方案的设计打下基础。

主动悬架用非均匀齿圆筒型永磁直线电机多目标分层优化设计

针对直线电机式电磁主动悬架推力波动大、推力密度低的问题,提出一种非均匀齿结构的Halbach圆筒型永磁直线电机。利用解析法对该电机的边端力模型进行推导,并进一步分析非均匀边端齿结构对电机输出性能的影响。根据分析结果选取边端齿的轴向长度和径向削短高度、永磁体高度和径向充磁的长度、内部齿的长度5个参数作为优化因子,以电机输出推力最大和推力波动最小为优化目标进行田口法和响应面法优化,得到参数的最优值。试制了原理样机并搭建了实验平台,对电机进行空载与负载实验,验证了所提结构及其设计优化方法的有效性。

新型分段定子开关磁阻电机转矩增强和径向力减小的分析研究

开关磁阻电机由于结构简单和启动转矩大等优点应用于许多领域,然而与永磁电机相比,其表现出较低的密度转矩和较大的振动噪声。文中提出一种新型分段定子开关磁阻电机,并在每个定子块两侧增设永磁体,构成分段定子混合励磁开关磁阻电机。首先介绍了拓扑结构和原理,磁路等效法证明了永磁体对气隙磁通加强作用,同时通过有限元仿真得出永磁体对转矩密度的影响并得出优化永磁体厚度。其次建立外转子齿顶开槽模型分析径向力减小的原理,同时对不同槽口宽度和深度模型仿真分析,得到优化尺寸。最后仿真表明,分段定子混合励磁开关磁阻电机的平均转矩提高了34.2%,转矩脉动下降了19.3%,定转子重叠区间的径向力波降低了12.5%,有效降低了径向力,改善了振动噪声。

New analytical solution for the analysis and design of permanent magnet thrust bearings

On the basis of the current sheet model,a new analytical solution for permanent magnet(PM) bearings is developed.Compared with analytical methods based on the coupling energy model and the magnetic dipole model,the proposed one is more physically intuitive and convenient for engineering designers.According to the analytical model,the thrust characteristics of a novel PM thrust bearing is studied and verified by finite element analysis(FEA).In the proposed thrust bearing configuration,the rotor is composed of stacked PM rings with alternative axial magnetization directions,and the stator with alternative radial magnetization directions while copper rings are used to separate adjacent PM rings.A prototype PM thrust bearing with the proposed configuration is designed and fabricated.The performances of the PM thrust bearing are experimentally validated.It is shown that the calculation accuracy of the presented analytical solution is satisfying.

矿用永磁接触器PI恒流充电控制器设计

为提高永磁接触器中储能电容的使用寿命,进而保证矿井下永磁接触器工作的可靠性,提出了一种基于比例积分(PI)算法的储能电容恒流充电控制策略。通过MATLAB搭建PI恒流充电仿真模型,构建了以Buck电路为硬件结构基础的改进型PI恒流充电控制器仿真实验平台。仿真和实验结果表明,储能电容在所提的改进型PI控制器调控下实现了恒流充电,符合预期恒流充电设定的参考值,对于增强电路稳定性、延长储能电容使用寿命以及提高整体控制器智能化程度有着一定的实用意义。

单线圈单稳态永磁式接触器机构动力学特性仿真分析

该文针对单线圈单稳态永磁式接触器并根据其操动机构特点,进行了基于 ANSYS 和 ADAMS 软件的永磁式接触器机构动力学特性仿真分析。该分析包含如下步骤:建立有限元模型应用 ANSYS 软件包仿真研究永磁式接触器的吸力特性;对永磁式接触器的操动机构和触头系统建立机械系统模型,应用 ADAMS 软件包进行多目标的动力学和运动学仿真分析;建立试验测试装置,对永磁式接触器的吸力特性和运动学特性进行测试,以验证仿真的正确性。该研究工作表明:应用该仿真研究大大缩短了永磁式接触器的开发周期和开发成本,为永磁式接触器这一新产品的工作性能和经济性能的不断提高提供了技术支持。

永磁式接触器动触头动作特性仿真分析与试验研究

针对单线圈单稳态永磁式接触器,采用仿真和试验的方法对永磁机构接触器的静态和动态动作特性进行了研究。首先,利用 ANSYS 软件包采用有限元模型,进行了动铁心静态吸力的仿真;其次,耦合电压平衡和达朗贝尔机械运动特征微分方程,在上述静态仿真的基础上进行了动铁心动态吸力的仿真。然后,利用 ADAMS 软件构建操动机构的机械模型,仿真动触头和动铁心的位移-时间特性。最后,设计试验用原型机进行试验,对仿真结果和试验结果进行对比分析,显示动触头动作特性仿真和试验结果一致性很好。

永磁接触器位移分段PWM控制及吸合过程动态特性分析

在分析永磁接触器吸合特性的基础上,提出位移分段的控制策略,实时检测接触器动铁心位移,并据此调整控制电压脉宽调制(pulse width modulation,PWM)占空比,使接触器的动态吸力和反力特性达到良好的配合,实现最优运动特性下的吸合控制。建立在位移分段PWM智能化控制下吸合过程的动态特性方程,耦合电压平衡方程和机械运动方程,采用4阶龙格-库塔算法仿真永磁接触器整个吸合动态过程。仿真结果与实验测量较吻合,验证了动态特性方程和仿真方法的正确性。最后,针对提出的控制策略,通过实验比较了4种不同分段的PWM控制方案,选出了最佳,可显著降低永磁接触器动触头及动铁心的闭合速度,并减少由其碰撞带来的触头一、二次弹跳。

无位置传感器的智能永磁接触器弱磁控制及合闸动态特性分析

针对永磁接触器提出了一种弱磁控制策略,实现合闸过程的智能化闭环控制,使其动态吸力和反力达到良好配合。结合磁路和电路模型,实现了动铁心实时位移信号的无位置传感器检测。耦合电压平衡方程和机械运动方程,建立了弱磁控制策略下合闸过程的动态数学模型,并采用4阶龙格–库塔法仿真了合闸动态过程。实验结果表明,通过调整和优化正、反向PWM占空比,可实现线圈正、反向电流的有效控制,由此调节动触头和动铁心的运动速度,使触头一、二次弹跳明显减少。仿真与实验结果比较吻合。

磁极偏移削弱永磁电机齿槽转矩方法

研究了永磁电机磁极偏移对齿槽转矩的影响,发现当每极槽数不为整数时,磁极偏移会引入新的齿槽转矩谐波。因此要通过磁极偏移减小齿槽转矩,除了减小永磁体对称时存在的齿槽转矩谐波外,还要减小新引入的低次谐波。为解决现有的永磁体偏移角度计算方法存在的不足,本文推导了磁极偏移时齿槽转矩的表达式,提出了确定永磁体偏转角度的新方法。有限元计算结果表明:与现有的方法相比,本文提出的磁极偏移角度计算方法得到的偏转角度对原有齿槽转矩谐波以及新引入的低次谐波都有较好的削弱作用,因此能较好地减小齿槽转矩。