Study of Steady-state Performances for a Novel Line-start Single-phase Permanent Magnet Synchronous Motor With Three Parallel-connected Windings

对于三相感应电动机的单相运行,学者们已经提出了多种实用的接线方式,比如Smith接法、SEMIHEX接法。然而,对于三相异步起动永磁同步电动机的单相运行,很少有合适的接法提出。将并联式接法应用于三相异步起动永磁同步电动机的单相运行,提出了一种新型三绕组并联式异步起动单相永磁同步电动机。分析了三相异步起动永磁同步电动机同步运行时以及起动瞬间的正序、负序阻抗,基于对称分量法,对该接法电机的对称运行条件进行分析,得出了电容的确定方法,并利用遗传算法对电容值进行优化。提出了该新型电机稳态性能的计算方法;设计了一台高功率因数和一台低功率因数三相异步起动永磁同步电动机作为样机,并分别将其改接为三绕组高效单相永磁同步电动机,进行实验研究。实验结果表明,低功率因数的异步起动永磁同步电动机更适合改接成新型三绕组并联式单相永磁同步电动机。由低功率因数三相永磁同步电动机改接成的单相异步起动永磁同步电动机在额定负载下运行时,具有与同容量三相永磁同步电动机相近的效率和更高的功率因数。

Sensorless Control of Permanent Magnet Synchronous Motor Based on New Sliding Mode Observer with Single Resistor Current Reconstruction

To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its stability is analyzed by using Lyapunov stability criterion.Secondly,according to the relationship among bus current,switching state and phase current,a single bus resistance sampling current reconstruction scheme without current sensors is adopted,which effectively reduces the cost of motor system.Finally,the feasibility and effectiveness of the proposed scheme are verified by simulation.

Zero-Sequence Current Suppression Strategy for Open-End Winding Permanent Magnet Synchronous Motor Based on Model Predictive Control

Compared with the traditional three-phase star connection winding,the open-end winding permanent magnet synchronous motor(OW-PMSM)system with a common direct current(DC)bus has a zero-sequence circuit,which makes the common-mode voltage and the back electromotive force(EMF)harmonic generated by the inverters produce the zero-sequence current in the zero-sequence circuit,and the zero-sequence current has great influence on the operation efficiency and stability of the motor control system.A zero-sequence current suppression strategy is presented based on model predictive current control for OW-PMSM.Through the mathematical model of OW-PMSM to establish the predictive model and the zero-sequence circuit model,the common-mode voltage under different voltage vector combinations is fully considered during vector selection and action time calculation.Then zero-sequence loop constraints are established,so as to suppress the zero-sequence current.In the end,the control strategy proposed in this paper is verified by simulation experiments.

Investigation of Optimal Split Ratio of 6-Slot/2-pole High Speed Permanent Magnet Motor with Toroidal Winding

Split ratio,i.e.the ratio of stator inner diameter to outer diameter,has a closed relationship with electromagnetic performance of permanent magnet(PM)motors.In this paper,the toroidal windings with short end-winding axial length are employed in the 6-slot/2-pole(6s/2p)PM motor for high speed applications.The split ratio is optimized together with the ratio of inner slot to outer slot area,i.e.slot ratio,considering stator total loss(stator iron loss and copper loss).In addition,the influence of maximum stator iron flux density and tooth-tip on the optimal split ratio,slot ratio,and average torque is investigated.The analytical predictions show that when the slot ratio is 0.5,the maximum torque can be achieved,and the optimal split ratio increases with the decrease of slot ratio,as confirmed by the finite element(FE)analyses.Finally,some of predicted results are verified by the measured results of 6s/2p prototype motor with 0.5 slot ratio.

THREE-PHASE BRIDGE INVERTER FOR 9kW DOUBLY SALIENT PERMANENT MAGNET MOTOR

The three-phase bridge inverter is used as the converter topology in the power controller for a 9 kW doubly salient permanent magnet （DSPM） motor. Compared with common three-phase bridge inverters, the proposed inverter works under more complicated conditions with different principles for special winding back EMFs, position signals of hall sensors, and the given mode of switches. The ideal steady driving principles of the inverter for the motor are given. The working state with asymmetric winding back EMFs, inaccurate position signals of hall sensors, and the changing input voltage is analyzed. Finally, experimental results vertify that the given anal ysis is correct.

Visualization and Quantitative Evaluation of Eddy Current Loss in Bar-Wound Type Permanent Magnet Synchronous Motor for Mild-Hybrid Vehicles

This paper describes the conductor eddy current loss that occurs in a permanent magnet type synchronous motor with a distributed winding stator using a rectangular copper wire designed for mild hybrid system applications for small vehicles.Compared with the conventional round wire inserter method,the space factor can be improved and the coil-end length can be shortened by applying a so-called hairpin windings using a pre-formed into hairpin shape of bar conductor,and as a result,DC current resistance of the armature winding can be reduced.However,since the conductor cross-sectional area tends to increases,the conductor eddy current loss generated by the space harmonics linkage becomes too large to ignore.In order to study the reduction of the conductor eddy current loss,it is important to visualize the spatial leakage flux distribution which causes loss and finely analyze how the magnetic path is formed.Therefore,analysis of the conductor eddy current loss distribution generated in the bar-wound conductor is performed using the CAE model that faithfully reproduces the coil-end shape of the actual machine.Furthermore,it was qualitatively clarified what ratio of conductor eddy current loss at various driving points.Finally,the results of preliminary study on reduction of conductor eddy current loss are reported.

Analysis of a new 5-phase bearingless induction motor

This paper addresses the bearingless motor with a single set of multiphase windings. The interaction between M and M±1 pole-pair magnetic fields produces radial force. Based on this principle,a bearingless machine is obtained. Conventional bearingless machine has dual windings,levitation windings and torque windings,which produce the two magnetic fields. In the proposed bearingless motor,the two needed magnetic fields are produced by feeding two groups of currents to a single set of multiphase windings. Taking a 5-phase induction motor as example,the inductance matrices,considering air gap eccentricity,are calculated with the modified winding function method. The radial force analytical model is deduced by virtual displacement,and its results are validated by FEA. The mathematical model of the new bearingless machine is set up,and the simulation results verified the feasibility of this novel bearingless motor.

Modeling of bearingless permanent magnet synchronous motor based on mechanical to electrical coordinates transformation

A bearingless permanent magnet synchronous motor(BPMSM)has two sets of stator windings,torque windings and suspension force windings.By analyzing the flux linkage intersection between the two sets of windings,a method of transforming mechanical coordinates to electrical coordinates is put forward.According to this method,flux linkage equations and voltage equations of the two stator windings are derived.The electromagnetic torque equation of the BPMSM is derived based on the analysis of the role of Lorentz force in the BPMSM.After analyzing the mathematical formula of various sort radial forces in the BPMSM,a complete function of radial suspension forces for the BPMSM is obtained.Finally,an experimental system control diagram and some test results are discussed.This mathematical model provides a theoretical foundation for BPMSM simulation study,experiment waveform analysis and structure design.

宽转子极无轴承开关磁阻电机径向力模型全周期拓展

针对单绕组宽转子极无轴承开关磁阻电机在定转子极非完全交叠区间的径向悬浮力模型空白、已有定转子极完全交叠区间径向悬浮力模型推导过程复杂且计算量大的不足,首先通过磁场有限元分析,分别确定了该电机在定转子非完全交叠区间和完全交叠区间的电磁场几何分布,计算了气隙磁密,再根据麦克斯韦应力法分别推导了这2个区间的径向力表达式,从而建立该电机在一个完整周期范围内的径向力数学模型,并通过与三维有限元计算结果的对比验证该模型的准确性。相比于利用等效磁路图推导径向力模型而言,该建模过程更简便,计算量也更小。全周期径向力模型的建立,不仅能为电机本体和控制器设计提供理论参考,还有助于提高该电机控制策略设计的灵活性,也可以提高与传统单绕组无轴承电机控制器的通用性。

基于滑模变结构的风电机组一次调频算法研究

针对并网风电场中,经典一次调频控制方法存在抗干扰能力弱、机组易脱网的问题,提出一种基于滑模变结构的风电机组一次调频控制算法。首先,在永磁同步风电机组工作原理的基础上,建立含有大电网的风电机组模型。其次,为了解决传统比例积分微分(proportional integral differential,PID)控制下抗干扰能力弱的问题、引入经典滑模变结构控制器。然后,针对经典滑模变结构控制器导致执行机构存在抖振较多的缺点,提出一种基于sigmoid函数趋近率的滑模变结构一次调频控制算法。最后,通过MATLAB/Simulink对风电机组一次调频进行建模仿真,并与经典控制算法相比,验证了所提算法的可行性,在风速波动和电网故障的环境下,滑模变结构一次调频控制算法更具有效性。

齿调制作用下转子开槽对永磁电机电磁振动影响

为了研究齿调制作用下转子表面开槽对永磁同步电机电磁振动的影响,以小功率分数槽集中绕组(FSCW)内置永磁同步电机(IPMSM)为研究对象,通过麦克斯韦应力张量法推导径向电磁力波的频率及空间阶数特征。分析齿调制作用在FSCW-IPMSM中将空间高阶电磁力波调制为低阶电磁力波的过程,并给出转子表面开槽在齿调制作用影响下与电磁振动间的联系。研究表明,转子表面开槽结构的改变会使各次谐波磁场发生变化,进而改变以极数阶电磁力波为代表的高阶电磁力波的幅值。在齿调制作用下,这些高阶电磁力波会被调制为幅值较高的低阶电磁力波,并引起不同幅度的低阶振动。然后建立C型、V型两种不同转子表面开槽结构的10极12槽FSCW-IPMSM电磁及结构有限元分析模型并进行仿真分析。结果表明,极数阶即10阶电磁力波会被调制为2阶并引起2阶振动,且两种不同开槽结构间的电磁振动存在着高达22.1%的差异。最后,在一台10极12槽样机上进行振动实验,验证理论与仿真分析结果。

共母线开绕组永磁同步牵引电机级联模型预测电流控制

为抑制共母线开绕组永磁同步牵引电机传动系统转矩脉动和由共模电压以及三次谐波反电动势作用于零轴回路产生的零序电流,提出一种自抗扰级联模型预测电流控制方法。首先,在第1级采用第1个有效电压矢量使得q轴电流增加,第2个有效电压矢量使得q轴电流减小,这一新的筛选组合规则将2个有效矢量根据对q轴电流作用效果分组寻优和作用时间分配;其次,在第2级对第1级所选有效电压矢量的零轴分量局部寻优,在第3级对第1级和第2级优化后系统产生的零轴电流分量采用极性相反的零矢量进行矢量分类寻优抑制,并精确分配作用时间;然后,在第4级对前3级所选电压矢量进行开关状态局部寻优,确定最优电压矢量的低开关频率状态组合作用于逆变器。最后,引入自抗扰控制减少电机启动加速过程中的调速超调,并对所提策略和双矢量模型预测电流控制进行稳态和动态仿真对比。结果表明:所提策略对转矩脉动、零轴电流、总谐波畸变率、开关频率和调速超调都具有很好的抑制效果,避免了传统模型预测控制的多目标代价函数中权重系数整定,对系统的控制性能有明显的提升作用。研究结果为进一步对共母线开绕组永磁同步牵引电机传动系统弱磁控制进行究,以及将驱动控制系统应用于机车牵引提供参考。

复杂工况下的永磁同步电机典型绕组故障在线诊断

绕组故障作为永磁同步电机常见的故障之一,严重影响电机正常运行。但由于电机运行工况复杂,故障特征波动严重,基于故障特征的诊断精度较低。为提高复杂工况下绕组故障的诊断精度,该文提出一种复杂工况下基于控制器信号的在线诊断方法。首先,对典型绕组故障进行故障机理分析,并通过基于自适应随机窗的快速傅里叶变换(FFT),提取控制器信号的相应故障特征;其次,通过研究单一工况和复杂工况下的各故障特征分布,揭示部分故障特征会在低转速工况下失效;再次,定义了复杂工况下故障特征性能指标,用于筛选故障特征;最后,在人工神经网络的基础上,提出了深度优化人工神经网络,引入批量归一化(BN)算法,并对深度网络结构残差化,提高网络泛化能力和诊断准确性。实验结果表明,通过计算故障特征性能指标,能够在诊断前对故障特征进行有效筛选,且深度优化人工神经网络的诊断准确性高、泛化能力强,在复杂工况下能够实现电机典型绕组故障的精确在线诊断。

应用于交流电机驱动的新型串联绕组拓扑的动态电流控制性能分析

电机绕组的动态电压是影响其电流变化能力的直接因素。为了提升电机的转矩响应速度,从直流电压利用率的角度分析串联绕组拓扑的动态电流控制能力。首先,从拓扑结构出发,相比于三相半桥拓扑,串联绕组拓扑将直流电压利用率提升了73%,这使得其动态电压更加充裕。然后,在不同的转速工况下,分析串联绕组拓扑、三相半桥拓扑以及采用电压修正策略的三相半桥拓扑的动态电流控制性能。最后,经仿真与实验证明,若采用电压修正策略来增大三相半桥拓扑的动态电压裕度,其只在转速接近额定转速时效果才凸显,且提升有限。而采用串联绕组拓扑,其在电压深度饱和下的电流动态响应时间将显著减小。

高功率密度永磁同步电机多物理场设计与优化

针对额定功率50 kW、额定转速2050 r/min的高效率高功率密度永磁同步电机进行多物理场优化设计,包括电磁场、温度场和应力场的设计与仿真分析。为进一步提高功率密度,选用发卡绕组替代传统的圆线绕组;为改善反电动势的正弦度,相较于传统的径向充磁,选用了多段式Halbach阵列充磁方式。本文给出了高功率密度电机的设计流程和电磁参数优化过程,通过多物理场仿真表明,本文所设计电机能够同时满足电磁指标和各项温升和应力指标。

集中绕组模块组合式定子结构对低速大功率永磁电机性能影响

针对集中绕组模块组合式定子结构对低速大功率直驱永磁同步电机性能的影响进行研究。首先介绍了模块化定子的分块规则和分块数。基于绕组函数法推导了单个定子单元模块在不同拆分方式下的绕组函数和电感表达式。基于有限元仿真先分析了仅绕组分块对电机性能影响;然后分析了冲片和绕组都分块对电机性能影响。通过对比空载和负载性能,总结出各种定子模块化拆分方案的优缺点,为大功率低速直驱永磁同步电机的模块化设计与制造建立了基础。

基于开绕组电机的电动汽车双电池集成充电系统准直接功率控制

针对基于开绕组永磁同步电机和双电池组驱动的电动汽车提出一种集成化充电拓扑,充电运行时将双逆变器和电机绕组复用为双PWM整流器及其输入侧滤波电感。在三相电压源型整流器(VSR)和开绕组永磁电机数学模型的基础上,将电网坐标系和电机坐标系相统一,分析了充电状态下的电磁转矩。实际运行时存在双电池剩余电量不相等的情况,导致充电时双通道功率不平衡,因此设计了一种准直接功率控制策略,以解决功率不平衡带来的转矩脉动问题。最后通过仿真和实验验证了该集成化充电拓扑的可行性。

基于谐振改进型单自由度自抗扰控制器的PMSM转速波动抑制策略

高性能系统期望电机输出平滑且稳定的转速。然而,永磁同步电机驱动系统的转速环遭受多源扰动影响,导致电机输出转速呈现非周期和周期波动。为了抑制转速环中多源扰动,该文提出一种谐振改进型单自由度自抗扰控制器(active disturbance rejection controller,ADRC)。单自由度ADRC保留了传统ADRC对非周期扰动的抑制能力。在此基础上,该文采用准谐振控制器拓展单自由度ADRC观测器在特定频率处的带宽,以进一步提高单自由度ADRC对周期扰动的抑制能力。因此,所提方法可以同时抑制转速的非周期和周期波动进而提高转速的控制性能。此外,该文利用Nyquist稳定判据分析所提方法的稳定性。最后,通过实验验证所提方法的有效性。

基于反推控制的永磁同步电机稳定性单矢量控制策略

针对永磁同步电机传统单矢量控制需遍历所有基本矢量且忽略控制稳定性的问题,该文提出基于反推控制的永磁同步电机稳定性单矢量控制策略。首先,在建立dq0坐标系下永磁同步电机数学模型的基础上,推导设计常规反推控制器;其次,根据反推控制器获取的控制电压确定最优电压矢量所在扇区,并通过数学推导证明每个扇区内必有一个稳定的基本电压矢量可供选择,提出通过基本电压矢量对应Lyapunov函数导数值两两比较的最优基本电压矢量选取方法;然后,对选取包括最优基本电压矢量在内的不同基本电压矢量时的控制性能进行对比分析;最后,对提出的控制策略进行仿真和实验验证。结果表明,在驱动恒转矩、恒惯量负载和变转矩、变惯量涡簧负载的多个场景下,该文提出的控制策略均能有效追踪参考转速,并且与传统模型预测电流控制相比,所提控制策略的稳定性更强、输出量波动更小。

高速高功率密度无轴承永磁薄片电机设计与优化

传统无轴承电机在高速和高功率密度之间难以取得平衡,为此围绕高速高功率密度无轴承永磁薄片电机,对其拓扑结构、绕组形式、主要尺寸等方面进行优化设计,在保证转速和功率密度的基础上有效地提升悬浮性能。通过对运行工况的分析,得出电机拓扑结构需具备的基本特点,提出一种采用环形集成绕组的表贴式无轴承永磁薄片电机。在兼顾转矩和悬浮力输出性能、机械防护可靠性的基础上,对电机的电磁气隙长度和永磁体参数等主要尺寸进行优化设计。针对电机饱和、绕组端部伸出等不利因素,分别采取了超前角弱磁、定子略长的性能提升策略,有效地避免了悬浮力的大幅度跌落。搭建20 000 r/min的无轴承永磁薄片电机有限元仿真模型并制造实物样机。通过对电磁转矩和主、被动悬浮力的分析,证明了本文设计的无轴承永磁薄片电机兼具良好的转矩与悬浮力输出性能,单位幅值电流产生的电磁转矩、主动悬浮力分别为0.166 N·m、4.4 N,电机输出功率10 kW、功率密度5.2 kW/kg。