A new separate‐identification method of two stator equivalent core‐loss resistances corresponding to hysteresis and eddy‐current losses for parallel‐type mathematical models of AC motors

This paper proposes a new unified method for identifying equivalent stator core‐loss resistance of AC motors, which can be applied to both induction and synchronous motors. In order to realize AC motors that exhibit high performance such as precise torque generation and/or efficient energy transmission, stator core loss cannot be neglected in designing vector control systems. It is common to model stator core loss in magnetic circuits as loss caused by equivalent resistance in electrical circuit. One of the best mathematical models for controlling AC motors with core loss is a kind of parallel‐type model that succeeds in modeling both eddy‐current and hysteresis losses. The newly proposed method succeeds in identifying separately and simultaneously two kinds of equivalent core‐loss resistances on the model corresponding to eddy‐current and hysteresis losses. The practical usefulness of the method is evaluated and confirmed through experiments using two induction motors of 5.5 and 2.0 kW having relatively high core losses and a permanent magnet synchronous motor of 750 W having relatively low core losses. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(4): 50–63, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10152     

Modeling and vector control of synchronous reluctance motorsincluding stator iron loss

The influence of the stator iron loss cannot be neglected since the high-speed operation and precision torque control of AC motors are required. This paper presents the modeling and vector control of synchronous reluctance motors including the stator iron loss. The stator iron loss is modeled by additional windings on the d-q axes, and is introduced as an equivalent iron loss resistance in voltage equations under the assumption that the losses in the stator core are produced in equivalent eddy current windings on d-q axes. The equivalent iron loss resistance is inserted in series with exciting inductance, and the d and q axes interfere with each other through the equivalent iron loss resistance. To achieve vector control, the d-q axis currents are decoupled by nonlinear control voltages. As a result, the instantaneous torque control scheme is equal to that of a DC machine and the torque control is simplified     

空压机用高速永磁电机铁心和磁钢损耗的影响因素

高速电机具有电流频率高、定子铁耗和转子涡流损耗大等特点。针对额定功率10 kW、额定转速100 000 r/min空压机用高速永磁电机,对比分析了平行充磁和径向充磁、脉冲振幅调制(PAM)方波驱动和基于SiC的正弦波驱动时对损耗的影响。分析结果表明,平行充磁气隙磁密谐波小,空载定子铁心损耗比径向充磁低约40%;驱动方式对电机损耗尤其是转子损耗影响较大,正弦波驱动时转子损耗几乎可忽略,方波驱动时转子损耗占比可达总损耗的20%。针对方波驱动转子损耗大的问题,在转子表面增加一层铜屏蔽层,分析结果表明可以有效降低转子涡流损耗。对同一台带压缩机负载的高速电机对比测试了2种驱动器控制下的母线输入的有功功率,验证了驱动方式对电机损耗的影响。     

New mathematical models of an induction motor using a minimum number of parameters

This paper proposes new mathematical models of an induction motor that generates torque precisely under vector control. The proposed models for the controlled motor have desirable features in respect to preciseness and compactness. They guarantee the same relation between the stator voltage and current signals as does the conventional T‐type model consisting of five parameters. The number of parameters forming the new models is reduced to four, such as stator resistance, inverse of rotor time constant, stator inductance, and stator total leakage inductance, or another set of four related uniquely to them. The parameters are uniquely determined by the stator signals, in terms of which all controller parameters of the vector control system can be designed. ©1998 Scripta Technica, Electr Eng Jpn, 126(2): 48–55, 1999     

Vector Control Specialized for Switched Reluctance Motor Drives

This paper proposes vector control specialized for a switched reluctance motor (SRM) drive. Because it is a unipolar drive, a sinusoidal current with a dc offset is applied to each circuit instead of the conventional trapezoidal current. The current consists of dc and ac components which can be identified by their generation of a (virtual) rotor flux and rotating stator magnetic field, respectively. Thus, the vector control system can be developed in the same way as conventional ac machines. The proposed technique provides new mathematical models of SRMs on a rotating reference frame and achieves precise and fast torque response and advanced operations such as linear torque‐current control and maximum‐torque‐per‐ampere control. The vector control theory was verified through simulations and experiments.     

轴向磁通永磁电机的设计与优化

本文根据一款家用乘用车的结构和运行性能需求,设计出了额定功率95kW,峰值功率190kW的轴向磁通永磁电机。电机采用内单定子外双转子结构,定子铁心采用分块式设计形式。基于永磁电机设计理论,总结归纳轴向磁通永磁电机的初始设计流程,并对其电磁性能进行初始评估。采用有限元法建立电磁分析三维模型,对采用多种转子结构电机的电磁转矩、齿槽转矩、转矩脉动及永磁体涡流损耗等进行计算和分析。文中所归纳的电动汽车驱动用轴向磁通永磁电机设计流程及降低齿槽转矩、转矩脉动和永磁体涡流措施的效果对比,为此类电机的设计及优化提供借鉴经验。     

磁性槽楔对永磁电机转子损耗及温度场影响

针对实心转子高压永磁电机定子铁心开槽会导致气隙磁导不均匀,气隙中谐波磁场引起电机转子温度升高,影响永磁体的电磁性能的问题,以一台315 k W,6 k V实心转子高压永磁电机为例,建立了样机的二维电磁场时步有限元模型及三维全域流体与固体耦合传热数学模型,给出了求解域及边界条件,通过求解计算模型,将计算数据与实验数据进行了对比,验证了所建模型的正确性。在此基础上研究了槽楔相对磁导率分别为3、5、7、9时对转子表面涡流损耗的影响,分析了磁性槽楔相对磁导率为不同值时电机转子及定子各部分的温度分布,计算结果表明定子槽楔相对磁导率数值的增加,电机的起动转矩降低,转子铁心涡流损耗逐渐减小,电机定子各部分温度先减小后趋于稳定。     

新型面装式永磁同步电机高性能控制技术

通过对面装式永磁同步电机矢量控制和直接转矩控制技术基本原理的对比分析,提出一种二者相结合的新型高性能控制技术。类似于矢量控制,其基本思想是对定子电流矢量进行解耦控制;类似于直接转矩控制,采用Bang-Bang控制器,通过选取合适的空间电压矢量来对定子电流励磁分量和转矩分量进行滞环调节,进而获得优异的转矩动态响应。该技术继承了矢量控制和直接转矩控制的优点并摒弃了各自的某些缺点,通过对三种控制技术仿真对比,表明基于该新型控制技术的面装式永磁同步电机控制系统静、动态性能优异,结构简单,计算量小,鲁棒性强。     

New block diagrams using vector signals in the general frame of reference for AC motors with stator core losses

This paper presents new block diagrams for induction and synchronous motors with stator core losses such as eddy‐current and hysteresis losses. The proposed block diagrams succeed in realizing simple and clear configurations with physically meaningful vector signals, which are helpful for understanding motor electromagnetic mechanism and useful for designing controllers for them. Vector signals, which are defined in the general reference frame, are utilized as transfer signals between blocks. The proposed vector‐signal block diagram in the frame can be directly and easily reduced to the one in such a specific frame as a stationary or synchronous frame simply by adding certain constraints to it. Shown are three configurations for induction motor, two for synchronous motors including permanent magnet cylindrical motor, permanent magnet salient‐pole motor, and reluctance motor. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 59–70, 2002     

补偿铁耗影响的永磁同步电机矢量控制

为了达到永磁同步电机高性能速度控制,电机铁耗的影响不能忽略.由此,本文得出了考虑铁耗时永磁同步电机(PMSM)的数学模型和矢量控制仿真模型.在d-q轴坐标系中,假设电机铁耗由一个等效的涡流绕组产生,从而在导出的电压方程式中,铁耗的效果用一个等效铁耗电阻来代替.由于等效铁耗电阻的存在,影响了d-q轴的磁链和电磁转矩,为了完成电机的矢量控制,必须补偿铁耗的影响.在Matlab/Simulink环境下构建了考虑铁耗时永磁同步电机的矢量控制模型,并与不考虑铁耗的矢量控制模型进行了比较.     

基于模糊控制的定子电阻辨识研究

定子电阻的变化影响异步电机矢量控制系统的性能.基于模糊控制理论,设计了一种结构简单的模糊定子电阻辨识器.在此基础上,根据矢量控制理论,采用Matlab/Simulink软件设计了异步电机矢量控制系统.仿真结果表明,辨识的定子电阻误差较小,系统响应迅速,转矩脉动小,鲁棒性好.     

轴向分段式双爪极永磁电机设计与分析

永磁同步电机在高频率工况时,定、转子铁心损耗和永磁体涡流损耗都会增加,使电机温度升高,从而导致绝缘老化、永磁体退磁等。为了解决高频损耗增加的问题,设计了一台定、转子铁心材料均为软磁复合材料的轴向分段式爪极定子、单段式爪极转子的双爪极电机。类似于双凸极结构会出现转矩脉动过大的问题,采用转子磁极偏移和定子斜极相结合的方式降低转矩脉动。最后,对电机的电磁设计和温度分布进行分析,验证设计的合理性。对于爪极参数的选取,研究主要尺寸比、极弧系数、转子磁极偏移距离和定子斜极角度对双爪极电机的气隙磁密、空载反电动势、转矩及转矩脉动的影响。     

定子磁场定向无速度传感器异步电机控制系统研究

提出一种改进的MRAS(模型参考自适应)磁链转速观测器,同时辨识了定子磁链和转子转速,并在此基础上实现了定子电阻的在线调整和定子电阻压降的补偿。在异步电机按定子磁场定向控制中,采用定子电阻压降补偿和电流转矩分量的闭环控制,实现了定子磁链的控制,系统具有较好的鲁棒性。     

基于槽极比选择的切向永磁同步电机永磁体涡流损耗抑制措施

为抑制切向永磁同步电机的永磁体涡流损耗,基于麦克斯韦方程和本构方程,对永磁体形状进行近似假设,构建了永磁体涡流损耗的估算模型。使用一种基于卡特系数概念的磁导函数来估算由于定子开槽引起的槽下磁感应强度变化。基于五台槽极比分别为1.05、1.20、1.30、2.40和3.60的电机设计方案对理论分析结论进行了验证。在负载电流和两倍负载电流下,分析永磁体损耗,得到了每台电机的径向气隙磁密曲线及其谐波含量。考虑到增加槽极比对定子铁耗和永磁体涡流损耗的削弱效果,给出了电机槽极比选择策略。研究结果表明,增加槽极比能减弱定子槽下磁感应强度变化,从而抑制气隙磁场中低次谐波含量,减小永磁体涡流损耗,使电机运行更加可靠,但也会引入更多高次谐波,从而增加定子铁耗。     

永磁同步电机矢量控制系统MTPA控制实现

分析了永磁同步电机矢量控制系统最大转矩电流比控制,并给出了一台15kW内置式永磁同步电机矢量控制系统分别在id=0控制和最大转矩电流比控制下的实验结果.实验结果表明,相比较于id=0控制,最大转矩电流比控制可减小定子电流,从而减小电机和逆变器损耗.     

Online tuning method of stator and rotor resistances in both motoring and regenerating operations for vector‐controlled induction machines

The vector control of induction motors is widely used. This method needs accurate motor parameter but the stator and rotor resistance vary due to motor temperature variation. If the value of resistance in the controller can be set up accurately at first, there must be a difference between the reference and real value of torque because of drift of the resistance. It is necessary to adapt the resistance value. The indirect field‐oriented control of an induction motor requires the value of rotor resistance only, but the direct field‐oriented control method with rotor flux observer requires the value of not only rotor resistance but also stator resistance in the controller. Consequently, it is necessary to adapt both stator resistance and rotor resistance. A parameter adaptation scheme has previously been proposed for the direct field‐oriented control method with rotor flux observer, but this method cannot be used when the motor is in regenerating operation. In this paper, a new stator and rotor resistance adaptation scheme is proposed, which can be applied when the motor is in regenerating operation. The usefulness of the proposed adaptation scheme is confirmed by simulation. © 2001 Scripta Technica, Electr Eng Jpn, 135(1): 56–64, 2001     

低转矩磁链脉动型电励磁同步电机直接转矩驱动系统的研究

电励磁同步电动机定子电感通常较小,转子阻尼绕组的存在使得电机暂态电感更小。若采用转矩及磁链滞环型直接转矩控制(基本DTC)策略电机电磁转矩及定子磁链脉动较大。针对电励磁同步电动机引入一种空间矢量调制型直接转矩控制(SVM-DTC)策略。它基于电励磁同步电动机中转矩角控制电磁转矩原理,利用空间电压矢量合成出最佳电压矢量实时补偿定子磁链矢量误差,以达到减小电动机在运行中电磁转矩及定子磁链脉动量之目的,同时又能基本维持开关频率恒定。仿真和实验结果证明,与基本DTC相比较,SVM-DTC电磁转矩和定子磁链脉动大幅度降低;电机起动电流峰值大大减小,稳态电流畸变较小;同时系统能够平稳地由恒转矩区过渡到弱磁区运行。     

一种改进的模型参考自适应定子磁链观测器

分析了几种常用磁链观测方法,提出一种改进的MRAS(模型参考自适应)磁链转速观测器,同时辨识了定子磁链和转子转速。在异步电机按定子磁场定向控制系统中,采用定子电阻压降补偿和电流转矩分量的闭环控制,实现了定子磁链的控制,系统具有较好的鲁棒性。     

基于矩阵变换器的感应电机矢量控制系统

研究了一种基于矩阵变换器的感应电机矢量控制系统,该系统将矩阵变换器的优点与交流电机矢量控制的优点相结合,实现了感应电机的高性能调速.调速系统的控制策略由两大部分组成,即矩阵变换器的间接空间矢量调制策略和感应电机按转子磁场定向的双闭环矢量控制策略.为有效控制感应电机的定子电流,双闭环矢量控制策略中采用了一种基于反馈解耦及补偿的电流环控制策略,可对转矩电流和励磁电流进行有效解耦和准确调节.实验证明了控制策略的可行性和有效性.     

基于转子磁场定向控制的PMSM伺服系统建模仿真

在分析永磁同步电动机（PMSM）数学模型的基础上，建立了的转子磁场定向矢量控制的PMSM伺服系统模型。系统采用位置、转速和电流三闭环控制，其中位置环和速度环采用经典的PI控制，电流环采用转子磁场定向矢量控制，以实现瞬时的转矩调节。仿真模拟了PMSM的恒转矩起动、恒功率运行以及负转矩制动的全过程，实现了位置伺服的精确控制。