Analysis of temperature field for a surface-mounted and interior permanent magnet synchronous motor adopting magnetic-thermal coupling method

Aiming at obtaining high power density of surface-mounted and interior permanent magnet synchronous motor(SIPMSM),it is important to accurately calculate the temperature field distribution of SIPMSM,and a magnetic-thermal coupling method is proposed.The magnetic-thermal coupling mechanism is analyzed.The thermal network model and finite element model are built by this method,respectively.The effects of power frequency on iron losses and temperature fields are analyzed by the magnetic-thermal coupling finite element model under the condition of rated load,and the relationship between the load and temperature field is researched under the condition of the synchronous speed.In addition,the equivalent thermal network model is used to verify the magnetic-thermal coupling method.Then the temperatures of various nodes are obtained.The results show that there are advantages in both computational efficiency and accuracy for the proposed coupling method,which can be applied to other permanent magnet motors with complex structures.

Airgap-harmonic-oriented Partitioned Design Method of PMV Motor with Improved Torque Performances

Here,we introduce a partitioned design method that is oriented toward airgap harmonic for permanent magnet vernier(PMV)motors.The method proposes the utilization of airgap flux harmonics as an effective bridge between the torque design region and the torque performances.To illustrate the efficacy of this method,a partitioned design PMV motor is presented and compared with the initial design.Firstly,the torque design region of the rotor is artfully divided into the torque enhancement region and ripple reduction region.Meanwhile,the main harmonics that generate output torque are chosen and enhanced,optimization.Moreover,the harmonics that generate torque ripple are selected and reduced based on torque harmonics optimization.Finally,the functions of the partitioned PMV motor torque are assessed based on the finite element method.By the purposeful design of these two regions,the output torque is strengthened while torque ripple is inhibited effectively,verifying the effectiveness and reasonability of the proposed design method.

Influence of Magnet Shape on the Cogging Torque of a Surface-mounted Permanent Magnet Motor

The influence of bread-loaf shaped magnet poles under parallel magnetization on the cogging torque of surface-mounted permanent magnet(SPM)motors is studied.For the SPM motors having magnetic poles with eccentricity and sine harmonic compensation,the electromagnetic performances of integer and fractional slot motors are compared.It is found that the cogging torque and torque ripple of the integer and fractional slot motors can be reduced with the same eccentric magnet pole.The cogging torque and torque ripple of a fractional slot motor can be decreased by sine harmonic compensation,however,the same sine harmonic compensation has a small influence in integer slot motors.By varying the magnetic poles,the contribution of the field harmonics(k=(2n+1)p),which are a direct result of magnet magnetization,to the cogging torque also changes.The electromagnetic performance of a 3 kW prototype is tested,and it is found that the experimental results validate the theoretical investigation.

Multi-Objective Optimization of Surface-Mounted and Interior Permanent Magnet Synchronous Motor Based on Taguchi Method and Response Surface Method

The surface-mounted and interior permanent magnet synchronous motor(SIPMSM)has the characteristics of multiple variables,strong coupling and nonlinearity.In order to improve the performance of SIPMSM,this paper presents a multi-objective optimal design process using Taguchi and response surface methodology(RSM).The peak value of cogging torque(PVCT),ratio value of average torque and permanent magnet weight(RTW),torque ripple and back-EMF total harmonics distortion(ETHD)are selected as optimization goals.The experiment matrix is established by Taguchi method,and analyzed the tendency and proportion of the effect of the optimization parameters on SIPMSM performance.The rules of choosing multi-objective optimization parameters are obtained.The least-squares method is used to establish the optimal objective function,and RSM is used to obtain the resolutions of the optimization objective function.Comparing the initial performance with optimized performance verifies the effectiveness of the proposed method.

Study on the Peripheral Magnetic Leakage and Shielding Measures of Surface-mounted Permanent Magnet Motor

Permanent magnet(PM)motors are widely used in our daily lives.Taking a surface-mounted PM motor as an example,a magnetic circuit model considering the peripheral magnetic flux leakage is established.Maxwell software is used to simulate different loads and thicknesses and the materials of the shielding layers.The magnetic flux leakage around the motor has a sinusoidal distribution in the space.The value of the magnetic flux leakage is inversely proportional to the power of P+1 from the surface of the core.The thicker the shielding layer,the smaller the magnetic leakage.The greater the relative permeability of the shielding layer,the better the shielding effect.The results provide ideas and recommendations for the magnetic flux leakage analysis and the design of non-magnetic or low magnetic motors.

一种交替极永磁游标电机设计与分析

提出了一种使用低成本铁氧体磁体的交替极永磁游标电机(CPPMVM).介绍了该电机拓扑结构,提出了基于特定磁导函数的等效磁场模型来推导主磁密、调制磁密和反电动势.通过解析法和有限元法分析该电机电磁性能、气隙磁密和谐波分布.结果表明:与常规表贴式永磁游标电机(SPMVM)相比,所提出的交替极永磁游标电机机械结构简单、成本低、谐波调制作用有效、转矩密度高、抗退磁能力强.

聚磁式交替极永磁游标电机分析与设计

为了在减少传统聚磁永磁游标电机永磁体用量时,仍能保持较大的转矩密度,提出一种新型聚磁式交替极永磁游标电机。与传统聚磁式永磁游标电机相比,新型拓扑结构电机通过交替极转子设计在减少永磁体用量时仍能保持较好的转矩输出特性。该文首先介绍了聚磁式交替极游标永磁电机的结构特点及工作原理。其次,以输出转矩最大为目标,利用有限元法对所提新结构电机关键参数进行优化分析。最后对比分析了新型聚磁式交替极永磁游标电机与传统聚磁式永磁游标电机的电磁性能,包括气隙磁密、反电势及转矩性能,结果表明在相同的体积下,所提新拓扑电机具有更高的转矩密度及更少的永磁体用量。因此,它在低速大转矩直驱应用场合具有广阔的应用前景。

基于FOCA的永磁游标电机PI参数自整定

针对磁场定向控制中电流内环和转速外环比例积分(PI)控制器参数整定困难且耗时长的问题,基于Matlab/Simulink的磁场定向控制自整定(FOCA)模块搭建了永磁游标电机磁场定向控制双闭环调速系统参数自整定模型。该模块在PI控制器输出端注入正弦扰动信号,根据系统输入输出数据计算频率响应,基于频率响应自动整定PI参数,同时实现指定的目标带宽和相位裕度。最后通过仿真对比分析各个环路整定前后的控制性能,仿真结果表明使用FOCA模块能够快速自动整定PI控制器参数并且拥有良好的控制性能。

基于联合仿真的表贴式永磁游标电机的伺服系统设计

研究了表贴式永磁游标电机的伺服系统,设计电机三环(即电流环、速度环、位置环)结构的伺服控制系统控制器,并分析伺服系统的动、静态性能。利用Maxwell、Simplorer及MATLAB/Simulink软件建立了表贴式永磁游标电机伺服控制系统联合仿真模型,研究了位置环参数对位置跟随系统快速性和准确性的影响。对比分析了电机三环结构伺服控制系统场路耦合仿真与定参数仿真。仿真结果表明,此控制策略可以实现表贴式永磁游标电机精准定位、无超调,且具有良好的快速性和抗干扰性。

分裂齿集中绕组永磁游标电机电磁转矩特性分析

为了研究分裂齿集中绕组永磁游标电机(PMVM)的电磁转矩特性,基于磁场调制原理建立PMVM的磁动势磁导模型,给出永磁体和电枢绕组单独作用下气隙磁密谐波的次数和转速表达式,分析产生平均转矩和转矩脉动的谐波次数。采用麦克斯韦应力张量法计算各主次谐波产生转矩的大小,确定各主次谐波对电磁转矩的影响。通过有限元分析对结果进行了验证。结果表明:PMVM的电磁平均转矩绝大部分由16次谐波产生,占比98.83%,转矩脉动主要由16、34、48次谐波产生,占比52.29%。PMVM电磁平均转矩的来源主要为永磁体产生的气隙磁密基波,因此可改变永磁体的用量和形状增大其产生的气隙磁密基波以提升PMVM电磁转矩性能。

内置式永磁游标轮毂电机结构参数多目标优化

外转子内置式永磁游标电机采用了磁调制原理,其内嵌永磁的结构能够提供额外的磁阻转矩,在低速大转矩方面有显著优势。研究了V形内置永磁游标电机,针对其磁路结构复杂、电磁参数多、不同性能指标之间难以平衡的问题,选取电磁结构参数作为优化对象,采用有限元的计算方法建立了BP神经网络代理模型,并利用NSGA-Ⅱ进行多目标优化,电机转矩和铁心损耗的优化率均达到10%以上,验证了多目标优化算法在内置式永磁游标电机设计方面的优越性。

永磁容错游标轮缘推进电机改进模型预测转矩控制

为提高永磁容错游标轮缘推进电机(FTPMV-RDM)在正常状态和一相开路故障状态下的控制性能,本文提出了一种基于电压矢量预选的改进模型预测转矩(MPTC)控制方法.针对六相独立H桥逆变器提供的备选电压矢量数量多导致MPTC系统计算量大的问题,首先,采用直接转矩控制中利用转矩、磁链误差及定子磁链位置信息确定预选电压矢量,减少MPTC系统中电压矢量的枚举次数.然后,利用价值函数进行二次筛选得到最优电压矢量.为了实现开路故障下的容错控制,提出了一种更换备选电压矢量表的开路故障容错控制策略.实验结果表明,基于电压矢量预选的FTPMV-RDM模型,本文预测转矩控制算法能够在无故障和一相开路故障下抑制电流畸变,进而有效降低转矩和磁链脉动.

永磁游标电动机双绕组低谐波设计与磁热性能比较

为削弱永磁游标电动机的电枢反应磁场中的无效谐波含量,实现电动机高效运行,基于磁场调制理论提出一种双绕组低谐波永磁游标电动机.首先,阐明谐波抵消原理;其次考虑到温升对导线和永磁体性能的影响,利用有限元法对传统永磁游标电动机和双绕组低谐波永磁游标电动机的电磁场和温度场进行双向耦合计算,并对气隙磁密、转矩和温升等性能参数进行对比.研究结果表明:得益于低谐波设计,双绕组低谐波永磁游标电动机的转矩和效率得到改善,相比传统永磁游标电动机,在常温20℃时,所提出的双绕组低谐波永磁游标电动机的平均转矩和效率分别增长2.62%和0.55%,转矩脉动下降50.15%;温度收敛至稳态后,双绕组低谐波永磁游标电动机的平均转矩和效率分别增长2.66%和0.57%,脉动下降50.16%,验证了该低谐波设计方案的有效性.

采用改进子域模型的表贴式永磁游标电机磁场解析计算

针对传统子域解析方法在计算气隙谐波磁场丰富的表贴式永磁游标电机磁场时,出现系数矩阵维数高、计算过程复杂的问题,提出了一种改进的子域解析模型。该模型通过坐标变换,将各子域矢量磁位在二维极坐标系下的拉普拉斯方程或泊松方程变换为准笛卡尔坐标系下的方程形式,利用分离变量法计算各子域矢量磁位方程的通解,根据边界条件计算待定系数,以双曲函数的形式表示各矢量磁位的解析解。计算了空载反电动势、气隙磁密和电磁转矩,与传统子域解析方法、有限元法计算结果进行对比。仿真结果表明:改进子域解析方法与有限元法的相对误差均小于1%;与传统子域解析方法相比,空载反电动势、气隙磁密和电磁转矩计算精度分别提升了1.7%、0.87%和3.66%。实验样机的空载反电动势计算波形和测试波形也基本吻合,验证了该方法的有效性和可行性。

裂齿式永磁游标电动机性能分析与比较

针对永磁游标电动机(permanent magnet vernier motor, PMVM)转矩密度大和功率密度高的特点,将其与传统永磁同步电动机(permanent magnet synchronous motor, PMSM)的性能进行比较研究.给出了6槽32极裂齿式PMVM的结构及工作原理,采用有限元仿真软件JMAG对其永磁磁场和电枢反应磁场的气隙磁密、空载感应电势、转矩、损耗等进行了分析,并与两台具有相同直径、轴长、定子齿数的PMSM进行了定量比较.结果表明:相比于6槽32极和6槽4极PMSM,6槽32极裂齿式PMVM平均转矩分别增加约45.0%和76.2%,转矩脉动减小约90.5%和95.0%,这揭示了PMVM转矩密度大、转矩脉动小的优点.然而,由于PMVM气隙中含有大量不同极对数、不同旋转速度的谐波磁场,导致其铁耗和永磁体涡流损耗较大.

永磁游标电机的多目标正交-粒子群优化

永磁游标电机有低速大转矩运行、直接驱动等优点,在保证转矩密度的同时降低转矩脉动是该类电机优化的主要目标。以内转子永磁游标电机为研究对象,利用敏感性分析确定优化因素,采用多目标正交优化、粒子群算法对该电机进行了优化,提出了二者相结合的正交-粒子群优化算法。利用有限元法对上述3种优化结果进行仿真,结果表明,该方法解决了正交优化精度不足和粒子群优化计算量大的问题;优化后使电机电磁转矩增加8.5%,转矩脉动减小8.23%,提升了电机的性能。

永磁游标电机虚拟矢量模型预测控制的研究

针对永磁游标电机(PMVM)模型预测控制策略中因备选电压矢量少和单个采样周期内电压矢量大小方向受限导致存在控制精度低和输出稳定性差的问题,在研究了传统模型预测控制原理的基础上提出了一种基于虚拟矢量的双矢量模型预测控制策略,该控制策略通过构建虚拟矢量的方法扩展了电压矢量有限集个数,在此基础上设计双矢量模型预测控制器,并对代价函数进行优化,提高了控制系统的稳定性和精确性,同时也减小了逆变器的损耗。最后在仿真软件中搭建控制系统模型进行对比仿真验证。结果表明,所提出的控制策略相比与传统模型预测控制策略有更好的动态稳定性和抗干扰性以及更高的控制精度。

扇型磁极直线游标电机多目标优化设计

针对扇型永磁直线游标(S-PMLV)电机优化目标多并且彼此之间相互制约的特点,运用田口法(TM)实现S-PMLV电机的多目标优化。选取推力、推力波动、铁耗与力能指标等特性作为优化目标,确定对目标影响大的优化参数与参数因子水平的取值范围。建立优化目标和参数影响因子的实验正交矩阵,并利用有限元法(FEM)进行求解,分析优化参数改变对S-PMLV电机性能指标影响的变化趋势与比重,得到最佳优化方案。通过比较优化前后的目标性能,结果表明,优化后S-PMLV电机的综合性能得到提升。

A Sensor-less Surface Mounted PMSM for Electronic Speed Control in Multilevel Inverter

Recent advancements in power electronics technology evolves inverter fed electric motors.Speed signals and rotor position are essential for controlling an electric motor accurately.In this paper,the sensorless speed control of surface-mounted permanent magnet synchronous motor(SPMSM)has been attempted.SPMSM wants a digital inverter for its precise working.Hence,this study incor-poratesfifteen level inverter to the SPMSM.A sliding mode observer(SMO)based sensorless speed control scheme is projected to determine rotor spot and speed of the multilevel inverter(MLI)fed SPMSM.MLI has been operated using a multi carrier pulse width modulation(MCPWM)strategy for generation offif-teen level voltages.The simulation works are executed with MATLAB/SIMU-LINK software.The steadiness and the heftiness of the projected model have been investigated under no loaded and loaded situations of SPMSM.Furthermore,the projected method can be adapted for electric vehicles.

混合永磁记忆电机全速域分段调速方法

针对钻机顶驱永磁电动机电能消耗大、退磁风险高、高效率调速范围窄等问题,提出以混合永磁记忆电机(HPM-MM)为核心的新型直驱式变频顶驱系统.根据HPM-MM不同磁化状态下永磁磁链与转速的对应关系,结合永磁体在线写极与超前角弱磁协调控制,使HPM-MM在具备永磁同步电机的优良特性外,还可以实现大范围平滑调速控制.通过计算转折速度划分运行区域,将运行区域分为恒转矩低速区和恒功率高速区.低速区使电机处于正向饱和充磁状态获得最大输出转矩.高速区包括弱磁Ⅰ区和弱磁Ⅱ区,弱磁Ⅰ区通过电机低矫顽力磁钢分段调磁实现高效调速;弱磁Ⅱ区采用超前角弱磁控制,通过重新分配定子电流进一步拓宽电机调速范围.该方法有效结合了HPM-MM本体的在线调磁与驱动协调控制能力,仿真分析验证了理论结果的有效性与可行性.