A dynamic mathematical model and vector block diagrams for class of hybrid‐field synchronous motors

This paper proposes a new dynamic mathematical model and new block diagrams for a newly emerging class of salient‐pole hybrid‐field synchronous motors (HFSM) that have rotor field by both permanent magnet and winding. The proposed mathematical model has the following completeness and generality. (1) It consists of three consistent basic equations such as circuit, torque, and energy‐transmission equations. (2) It deals with pole saliency and contains nonsaliency as a special case. (3) It is a dynamic model and contains a static one as a special case. (4) It is established in the general reference frame including stator and rotor reference frames as special cases. The proposed new block diagrams using vector signals for salient‐pole HFSM are established based on the model. It has the following attractive features. (1) It succeeds in realizing clear configurations with physically meaningful vector signals, which are helpful for understanding motor electromagnetic mechanisms and useful for designing controllers for the salient‐pole HFSM. (2) Vector signals utilized as transfer signals between blocks are defined in the general reference frame. Consequently, the vector‐signal block diagrams in the frame can be directly and easily reduced to the ones in such a specific frame as stator and rotor frames. (3) It is compact. Two typical and compact but sufficiently general vector‐signal block diagrams are newly presented. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(2): 47–57, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20112     

A new current control method for energy‐efficient/wide‐speed‐range drive of permanent magnet synchronous motor

This paper proposes a new current control method for energy‐efficient and/or wide‐speed‐range drive of salient‐pole permanent magnet synchronous motors. The proposed method is distinguished from conventional ones by the following features. (1) The original command is a signed current norm. (2) The exact d‐axis and q‐axis current commands that perform energy‐efficient and/or wide‐speed‐range drive are analytically and simply determined from the singed current norm command. (3) For speed control mode, the system turns out to be nonlinear, but its stability can be guaranteed based on Popov's stability theorem. (4) It can be applied for a mode similar to torque control. (5) Current limitation can be carried out accurately but very simply. Concrete analytical d‐axis and q‐axis current commands are presented, which satisfy exactly one of three optimum current control codes such as maximum torque, maximum power factor, and voltage limitation. A design method for PI speed controller that guarantees system stability is also presented. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(3): 66–77, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20305     

New Simple Torque‐Sensorless Torque Control for Quasi‐perfect Compensation of Sixth‐Harmonic Torque Ripple Due to Nonsinusoidal Distribution of Back EMF of PMSM

This paper proposes a new torque‐sensorless torque control method for permanent‐magnet synchronous motors (PMSMs). The proposed method can almost perfectly compensate the sixth harmonic torque ripple that is caused by nonsinusoidal distributions of the back electromagnetic force and the rotor magnetic flux of PMSMs. The torque control system is, in principle, constructed on the basis of vector control, but has two new, dedicated speed‐varying devices: a harmonic torque observer and a current controller. The speed‐varying harmonic torque observer can estimate the harmonic component over a wide range of speeds, even when the generated torque is constant, and produce a suitable compensation signal. The speed‐varying current controller shows stable control performance over a wide range of speeds; it can fully track the compensated current command containing the DC and sixth harmonic components. The effectiveness of the proposed method is examined and verified through extensive numerical experiments.     

A General Analytical Method for a Three‐Phase Line‐Start Permanent‐Magnet Synchronous Motor

A line‐start permanent‐magnet synchronous motor (LSPMM) consists of a stator with symmetrical three‐phase armature windings and a salient pole rotor with a permanent magnet for excitation and a starting winding similar to the squirrel‐cage winding of an induction motor. In this paper, a general analytical method based on tensor analysis is proposed for practical performance calculation of a three‐phase LSPMM. The general equation for the currents of the three‐phase LSPMM is derived from the transient impedance tensor expressed in polyphase symmetry axes, and the general equation for vibratory and nonvibratory torques is derived from the current equation. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 185(4): 60–68, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21284     

基于串级绕组的新型永磁同步电机起动性能分析

针对异步起动永磁同步电机在起动过程中电流大,起动转矩小的问题,本文提出一种串级绕组理论。利用定子串级绕组产生的谐波磁场与转子分匝线圈组相互作用,优化电机的起动性能。文章通过阐述串级绕组理论,给出电机模型与定转子设计方案,并基于等效电路分析样机实际工作原理,最后运用有限元法从样机的转速、空载起动性能、带负载起动、气隙磁密和堵转转矩五个方面进行仿真。试验结果表明,应用串级绕组理论可以在提高起动转矩的同时降低起动电流,抑制起动时定子电流对转子永磁体的退磁效应,并且电机的稳态性能保持不变。     

New Simple High‐Quality Torque Control for Permanent‐Magnet Synchronous Motors: Compensating for Torque Ripple Caused by Nonsinusoidal Back EMF

This paper proposes a new and simple torque‐sensorless torque control method for permanent‐magnet synchronous motors (PMSMs) with nonsinusoidal back EMF. The method suppresses the sixth and/or 12th harmonic torque ripples caused by the back EMF in a feedforward manner even at high speeds; it consists of two subordinate methods for compensation command generation and command‐tracking current control. The first subordinate method generates compensation current commands to cancel the torque ripples based on a mathematical model of PMSMs. The second method controls the stator current to track a current command containing both fundamental and compensatory components. In conjunction with the current control, a dedicated disturbance observer that employs a digital speed‐varying band‐pass filter as a disturbance filter is also proposed. The effectiveness and usefulness of the proposed method were verified through extensive experiments.     

不同绕组连接方式下的六相永磁同步电动机MT容错控制

多自由度使多相电机具备了优异的容错能力。本文针对单中性点、双中性点及开端绕组结构的六相永磁同步电机,以缺相容错运行时输出转矩最大为目标,提出一种适用于不同绕组结构电机的容错电流计算通用表达式。通过对六相永磁同步电机缺一相故障状态下的自由度进行分析,计算了不同定子绕组结构下的容错电流,并给出相应的控制方法。对比三种不同绕组结构电机容错运行时的带载能力,开端绕组结构的六相永磁同步电机缺相容错运行时输出转矩最大。利用Matlab/Simulink建立了六相永磁同步电机模型及其控制系统,验证了计算结果的有效性。     

基于退磁限制的无轴承永磁同步电机性能参数分析

无轴承永磁同步电机磁场中不仅存在转矩绕组电流产生的磁通,而且存在径向悬浮力绕组电流产生的磁通,这两种磁场会导致永磁体退磁。设计永磁体参数需考虑产生最为有效径向悬浮力、电磁转矩和避免永磁体退磁三者之间的关系。论文分析了转矩绕组电流产生的磁通和径向力绕组电流产生的磁通共同作用下,转子表面永磁体容易引起退磁的关键区域;在电机气隙不变情况下,分析得出了保证产生最为有效的径向力时最佳永磁体厚度;基于永磁体退磁限制,采用有限元分析计算,针对论文中设计的永磁体厚度及气隙长度,得出了无轴承永磁同步电机最大转矩电流、径向悬浮力电流和产生的最大径向悬浮力。     

Rotor position and velocity estimation for a salient-pole permanentmagnet synchronous machine at standstill and high speeds

This paper addresses self-sensing (“sensorless”) control of salient-pole permanent magnet synchronous motors (PMSMs). The major contribution of this work is the introduction of a simple-to-implement estimation technique that operates over a wide speed range, including zero speed. The technique achieves simplicity by decoupling the inherent cross-coupling in PMSMs. The technique utilizes the dependence of inductance on rotor position in interior permanent magnet machines to produce position and velocity estimates both for field orientation and for all motion control of the drives. The technique functions in a manner similar to a resolver and resolver-to-digital converter (RTDC) sensing system, whereby in the proposed technique the motor acts as the electromagnetic resolver and the power converter applies carrier-frequency voltages to the stator which produce high-frequency currents that vary with position. The sensed currents are then processed with a heterodyning technique that produces a signal that is approximately proportional to the difference between the actual rotor position and an estimated rotor position. This position error signal and a torque estimate are then used as inputs to a Luenberger style observer to produce parameter insensitive, zero lag, position and velocity estimates     

Machine parameters and performance of interior permanent magnet synchronous motors with different permanent magnet volume

Permanent magnet synchronous motors are widely used for several industrial applications. Some applications such as electric vehicles and compressor drives require a constant power operation. The operating limits and the constant power speed range deeply depend on the machine parameters. The relationships between the motor parameters and the operating performance have been theoretically examined. This paper examines the performances of the prototype synchronous motors, where the stator structure and the rotor structure of all motors are the same. The permanent magnets are inserted into the rotor slits and the volume of the permanent magnet is adjusted to control the magnet‐flux linkage. The effects of adding the magnet to the rotor on the machine parameters and the operating performance are examined based on the various experimental results. The prototype motor has flexibility as to speed versus power performance by adjusting the volume of the permanent magnet. The theoretical results with respect to the operating limits and the motor parameters are also confirmed experimentally. © 2000 Scripta Technica, Electr Eng Jpn, 131(4): 70–77, 2000     

考虑转子异步损耗的永磁同步电机高效率控制研究

永磁同步电机（Permanent Magnet Synchronous Motor）功率密度高、转动惯量小、动态响应快,广泛用于电动汽车的驱动、伺服系统和工业等场合。考虑了电机在加速、减速等动态工况工作时产生的转子异步损耗,实现永磁同步电机损耗最小控制,建立了考虑转子异步损耗的永磁同步电机模型,采用数值方法求解电机模型;以电机输入功率最小为目标函数,通过基于模型的黄金分割算法在线搜索当前工况下的最优定子磁链,避免搜索过程中电机的抖动。结果表明,与传统的最大转矩电流比和弱磁控制相比,在加速、减速时总损耗都有明显降低,在额定转速以上响应更快,转矩动荡小。所提出的控制策略实现了动态工况下电机损耗最小,达到了节能的目的。     

Analysis and characteristics of a permanent magnet-type bearingless motor

Super-high-speed and high-power electric machines are required for turbomolecular pumps and spindle drives. High rotational speed and high-power drives can be achieved with bearingless motors. In this paper, a bearingless motor with principles of permanent magnet-type synchronous motors is proposed. High-power factor and high efficiency can be expected in permanent magnet-type bearingless motors. The proposed bearingless motor is a 4-pole permanent magnet synchronous motor, in which additional 2-pole windings are wound together with 4-pole motor windings in stator slots. With currents of 2-pole windings, radial magnetic forces are produced to support a rotor shaft. Principles of radial force production of surface-mounted permanent magnet bearingless motors are analyzed mathematically. The relationships between radial forces and the permanent magnet thickness were derived. From these relationships, the optimal permanent magnet thickness to produce radial forces efficiently is found. A test machine was built to confirm the relationships of radial forces, currents and voltages.     

基于响应面法的定子永磁型轴向磁通切换电机齿槽转矩优化设计

针对聚磁反应造成定子永磁型轴向磁通切换电机(SPAFFSPM)的齿槽转矩偏大、噪声大等问题。以减小定子永磁型轴向磁通切换型电机的齿槽转矩,提高电机的输出性能为目标,利用能量摄动法推导出电机的齿槽转矩解析表达式,分析影响齿槽转矩的定转子结构参数。基于响应面法与有限元法构造出定子槽弧宽、转子齿倾斜角及永磁体形状系数与齿槽转矩之间的响应面数学模型,推导出使齿槽转矩最小的定子槽弧宽、转子齿倾斜角及永磁体形状系数最优组合。最后建立优化前后电机三维有限元分析模型,搭建样机的实验平台,验证优化方法的合理性及准确性。结果表明,优化后的电机齿槽转矩减小约82.5%,且电机的输出性能得到明显提高。     

Sensorless vector control of PMSM with non-sinusoidal flux using observer based on FEM

Back electromotive force method has been widely used in the position and speed sensorless control of permanent magnet synchronous motors. In this method, it is supposed that the back electromotive forces induced on the stator windings by the rotor permanent magnets are sinusoidal. This assumption causes errors in the estimation of speed and position. In this paper, an observer using the stator winding linkage flux model obtained by using finite element method for position and speed sensorless field-oriented control of permanent magnet motor is proposed. The validity of the proposed method is demonstrated using DS 1104.     

U型单相自起动永磁同步电机参数计算与起动特性分析

为了使U型单相永磁同步电机实现自起动,气隙采用非对称形式。文中基于二维有限元法对电机绕组电感、磁链和定位转矩进行了计算。在此基础上,针对所建立的动态数学模型,用龙格库塔法对空载起动过程进行了动态仿真计算,得到该电机电流、转矩和转速曲线。同时讨论了电源合闸角、转子初始相角、磁链和负载转矩对电机转速和旋转方向的影响。本文所论述的工作为该电机的进一步理论研究与优化设计奠定了基础。     

Characteristics of a permanent magnet type bearingless motor

Super high-speed and high-power electric machines are required for turbomolecular pumps and spindle drives. High rotational speed and high power drives can be achieved with bearingless motors. In this paper, a bearingless motor with the principles of permanent magnet type synchronous motors is proposed. High power factor and high efficiency can be expected in permanent magnet type bearingless motors. The proposed bearingless motor is a 4 pole permanent magnet synchronous motor, in which additional 2-pole windings are wound together with 4-pole motor windings in stator slots. With currents of 2-pole windings, radial magnetic forces are produced to support a rotor shaft. Principles of radial force production of surface-mounted permanent magnet bearingless motors are analyzed mathematically. It was found that radial forces are efficiently produced by employing thin permanent magnets on the surface of rotor iron core. A test machine was built in order to measure inductance functions as well as relationships between voltages and currents     

磁动势法五相永磁力矩电机转矩分析

五相永磁力矩电机由于极数与槽数相近,含有丰富的磁动势谐波,磁动势谐波会影响电机的转矩性能。为此,采用磁动势法分析电机的电磁转矩,通过磁能和虚位移原理推导出了电机电磁转矩的解析表达式,揭示了具有相同空间次数的定子和转子磁动势谐波相互作用才能产生电磁转矩的规律。通过对五相永磁力矩电机的定、转子磁动势谐波与电磁转矩关系的分析,指出与与主波转速一致的定子和转子磁动势谐波相互作用能提高五相永磁力矩电机的平均电磁转矩。利用Ansoft有限元软件仿真分析了电机在正弦波、梯形波和方波供电下的定子磁动势、转子磁动势以及转矩性能。结果表明,非正弦供电能够增加电机的电磁转矩,但也带来了转矩脉动,验证了磁动势法分析五相永磁力矩电机转矩的有效性和正确性。     

一种新型混合转子双定子同步电机的转矩解耦矢量控制

为了提高低速直驱永磁同步电机的转矩密度,充分利用其内腔空间,本文针对一种新型混合转子双定子同步电机,提出一种适用的矢量控制策略。该种电机的转子一侧采用表贴式永磁转子结构,另一侧采用磁阻转子结构,该种新型混合转子结构同时还解决了传统双定子永磁同步电机成本高的问题。针对该种特殊结构新型电机,本文提出一种转矩解耦矢量控制方法,利用转矩解耦系数实现了内外电机的转矩解耦控制。在Matlab/Simulink仿真环境下,对新型混合转子双定子同步电机及其矢量控制系统进行模型建立和仿真分析。仿真结果验证了所提出电机模型及其控制系统的可行性和正确性,且控制效果理想。     

Loss Analysis of Permanent-Magnet Motors With Concentrated Windings—Variation of Magnet Eddy-Current Loss Due to Stator and Rotor Shapes

In this paper, we investigate losses, including magnet eddy-current loss of permanent-magnet synchronous motors with concentrated windings. A 3-D finite-element method that considers carrier harmonics of pulsewidth modulation inverters is utilized to calculate the losses in each part of the motor separately. A simple linear magnetic circuit model is also introduced in order to understand the mechanism of eddy-current loss generation in the magnet. First, the measured and calculated results are compared to verify the validity of the analysis. Next, the variation of the losses due to the stator and rotor shapes is investigated, for instance, concentrated and distributed stator windings and interior and surface-mounted permanent magnets. It is clarified that the eddy-current loss of the permanent magnet in the concentrated winding motor is much larger than that in the distributed winding motor. The difference of the loss generation mechanism due to the rotor shape is also clarified.     

基于dSPACE的永磁同步电机转子位置和速度估计方法

讨论了基于dSPACE实现永磁同步电机转子位置和速度估计的方法。通过测量电机的端电压和流过定子线圈的电流，采用扩展卡尔曼滤波在线估计电机转子的位置和速度，实现了PMSM的无传感器控制。实验结果验证了该方法消除了无传感器控制策略的缺点，具有较好的控制效果。