Five-phase Synchronous Reluctance Machines Equipped with a Novel Type of Fractional Slot Winding

Multi-phase machines are so attractive for electrical machine designers because of their valuable advantages such as high reliability and fault tolerant ability.Meanwhile,fractional slot concentrated windings(FSCW)are well known because of short end winding length,simple structure,field weakening sufficiency,fault tolerant capability and higher slot fill factor.The five-phase machines equipped with FSCW,are very good candidates for the purpose of designing motors for high reliable applications,like electric cars,major transporting buses,high speed trains and massive trucks.But,in comparison to the general distributed windings,the FSCWs contain high magnetomotive force(MMF)space harmonic contents,which cause unwanted effects on the machine ability,such as localized iron saturation and core losses.This manuscript introduces several new five-phase fractional slot winding layouts,by the means of slot shifting concept in order to design the new types of synchronous reluctance motors(SynRels).In order to examine the proposed winding’s performances,three sample machines are designed as case studies,and analytical study and finite element analysis(FEA)is used for validation.

Torque Ripple Reduction of Synchronous Reluctance Machine by Using Asymmetrical Barriers and Hybrid Magnetic Core

As there is no need of permanent magnet(PM)material and only silicon steel sheet required on the rotor,synchronous reluctance machine(SynRM)can be used for many applications and draws a great research interest.For the SynRM,the torque ripple is a big issue and a great of work could been done on reducing it.In this paper,asymmetrical magnetic flux barriers in the SynRM rotor were studied comprehensively,including angle and width of each layer and each side of the magnetic barrier.The SynRMb with asymmetrical and parallel magnetic flux barrier was found as the best way to design SynRM based on the multi-objective design optimization method.Moreover,each parameter was studied to show the design rule of the asymmetrical magnetic flux barrier.As the average torque will be reduced with the asymmetrical barrier is used,the grain-oriented silicon steel is used on stator teeth of the SynRMb(SynRMbG)was proposed and studied.The analysis results show that the proposed new method can make the SynRM have better performance.

Square-Wave Drive for Synchronous Reluctance Machine and its Torque Ripple Analysis

Synchronous reluctance machine(SynRM)can be perceived as a special type of permanent magnet synchronous machine(PMSM),and shares similar control method,i.e.the sine-wave current drive with sinusoidal phase currents.In this paper,square-wave drive,which is employed for permanent magnet brushless(BLDC)motors,is employed for the SynRM,in order to economically reduce the cost of rotor position sensor.It is revealed that the torque density and efficiency are slightly sacrificed,whereas torque ripple is deteriorated,proving the SynRM with square-wave drive still promising for the cost-sensitive application if torque ripple is not considered as a critical issue.To further investigate the additional pulsating torque under square-wave drive,mathematical model based on a-b-c phase inductance and d-q axis inductance are established,together with the time-stepping FE calculated currents.It is concluded that the harmonics in the currents tend to cause non-sinusoidal variation of the magnetic reluctance,which can be represented as additional inductance harmonics.The harmonics of the current and inductance interact with each other,thus undesirable torque ripple components are produced.

Design Methods of Transversally Laminated Synchronous Reluctance Machines

Transversally laminated synchronous reluctance machine(SynRM)are usually designed with multiple-layer flux barriers to achieve high electromagnetic performance.This paper summarizes three design methods to optimize the machine.Related implementation procedures are detailed.Besides,advantages and disadvantages of these methods are discussed.Based on these conventional techniques,a comprehensive optimization method is proposed,with which a prototype SynRM is designed.The performances of this prototype are discussed to verify the optimal design method.

Multi-objective Hierarchical Optimization of Interior Permanent Magnet Synchronous Machines Based on Rotor Surface Modification

To solve the problem of large torque ripple of interior permanent magnet synchronous motor(IPMSM),the rotor surface notch design method was used for V-type IPMSM.In order to accurately obtain the optimal parameter values to improve the torque performance of the motor,this paper takes the output torque capacity and torque ripple as the optimization objectives,and proposes a multi-objective layered optimization method based on the parameter hierarchical design combined with Taguchi method and response surface method(RSM).The conclusion can be drawn by comparing the electromagnetic performance of the motor before and after optimization,the proposed IPMSM based on the rotor surface notch design can not only improve the output torque,but also play an obvious inhibition effect on the torque ripple.

Recent Development of Reluctance Machines with Different Winding Configurations,Excitation Methods,and Machine Structures

This paper reviews the performances of some newly developed reluctance machines with different winding configurations,excitation methods,stator and rotor structures,and slot/pole number combinations.Both the double layer conventional(DLC-),double layer mutually-coupled(DLMC),single layer conventional(SLC-),and single layer mutually-coupled(SLMC-),as well as fully-pitched(FP)winding configurations have been considered for both rectangular wave and sinewave excitations.Different conduction angles such as unipolar􀫚120°elec.,unipolar/bipolar􀫚180°elec.,bipolar􀫛240°elec.and bipolar􀫜360°elec.have been adopted and the most appropriate conduction angles have been obtained for the SRMs with different winding configurations.In addition,with appropriate conduction angles,the 12-slot/14-pole SRMs with modular stator structure is found to produce similar average torque,but lower torque ripple and iron loss when compared to non-modular 12-slot/8-pole SRMs.With sinewave excitation,the doubly salient synchronous reluctance machines with the DLMC winding can produce the highest average torque at high currents and achieve the highest peak efficiency as well.In order to compare with the conventional synchronous reluctance machines(SynRMs)having flux barriers inside the rotor,the appropriate rotor topologies to obtain the maximum average torque have been investigated for different winding configurations and slot/pole number combinations.Furthermore,some prototypes have been built with different winding configurations,stator structures,and slot/pole combinations to validate the predictions.

Inductances Estimation in the d-q Axis for an Interior Permanent-Magnet Synchronous Machines with Distributed Windings

The inductances in d-q axis have an important influence on the behavior of PMSM （PM （permanent-magnet） synchronous machines）. Their calculation is fundamental not only to evaluate the performance such as torque and field weakening capability but also to design the control system to maximize performance and power factor. This paper presents a study of inductance in the d-q axis for buried （i.e., IPMSM （interior） PM Synchronous Machines）. This study is achieved using 2-D （two-dimensional） FEM （finite-element method） and Park＇s transformation.

Quantitative Comparison of Electromagnetic Performance of Electrical Machines for HEVs/EVs

In this paper,various types of sinusoidal-fed electrical machines,i.e.induction machines(IMs),permanent magnet(PM)machines,synchronous reluctance machines,variable flux machines,wound field machines,are comprehensively reviewed in terms of basic features,merits and demerits,and compared for HEV/EV traction applications.Their latest developments are highlighted while their electromagnetic performance are quantitatively compared based on the same specification as the Prius 2010 interior PM(IPM)machine,including the torque/power-speed characteristics,power factor,efficiency map,and drive cycle based overall efficiency.It is found that PM-assisted synchronous reluctance machines are the most promising alternatives to IPM machines with lower cost and potentially higher overall efficiency.Although IMs are cheaper and have better overload capability,they exhibit lower efficiency and power factor.Other electrical machines,such as synchronous reluctance machines,wound field machines,as well as many other newly developed machines,are currently less attractive due to lower torque density and efficiency.

Optimization of Added Permanent Magnet Amount in Synchronous Reluctance Machines for High Performance

An optimizing method of adding permanent magnet into synchronous reluctance machines for high performance is presented. The method enables torque components from reluctance and permanent magnet to reach an optimal combination so as to obtain a maximum efficiency, higher power factor in a wider speed range. Capability curves of synchronous reluctance combined with permanent magnet (SR PM) machines are described for different quantities of permanent magnet. The interacting principle of reluctance and permanent magnet torque is discussed. Simulation results based on an integrated model of the SR PM machine with a controller are presented to demonstrate the interaction of the two kinds of torques. Particularly, efficiency contours over the capability curves are illustrated to show the effect of added permanent magnet amount. An optimizing criterion for added permanent magnet amount in SR PM machine design is developed. Compared to induction, pure synchronous reluctance, and non optimized SR PM machines with same stator, the optimized SR PM machine shows higher efficiency in a wider speed range.

Advanced Computer-aided Design and Analysis for Synchronous Reluctance-Permanent Magnet Machines

This paper presents an advanced computer aided design (CAD) package for the synthesis, analysis, and optimization of synchronous reluctance combined with permanent magnet (SR PM) machines. The distinguishing features of the CAD package are that it allows a wide range of design options and parameter variations for the new type of machines, calculations of optimization for maximum efficiency and higher power density, and various performance. The package as described in the main text permits the integration of the machine design with an electronic controller, along with the simulation of the whole system. Through the optimal design, characteristic calculations, and system simulations, the CAD package offers a superior design for the SR PM machines, and presents a feasibility frontier outlined by the design.

Review of Parameter Identification and Sensorless Control Methods for Synchronous Reluctance Machines

Synchronous reluctance machines(SynRMs)have drawn increasing attention in recent years owing to their advantages such as low cost,simple structure,ease of manufacture,and high robustness.The main obstacle to the promotion of SynRMs is severe parameter nonlinearity,which deteriorates drive performance.Sensorless control methods for SynRMs are critical technologies that can broaden the industrial applications of SynRMs.Various methods of parameter identification and sensorless control strategies are reviewed and discussed,including self-commissioning,which is analyzed in detail.Furthermore,sensorless control strategies that can improve the industrial application of SynRMs are described.Finally,future research trends concerning SynRMs are analyzed and discussed.

同步磁阻电动机研究

该文根据能量平衡观点,以异步电动机为参照,较全面地分析了Xd、Xq和凸极比K对磁阻电动机性能的影响,讨论了凸极比适合值的选择问题,并指出对cosj小于0.85以下的小容量电机,同步磁阻电动机在应用中可与异步电动机匹敌。

同步磁阻电机分析与设计(连载之十二) 永磁辅助同步磁阻电机的设计研究

针对两层磁障的同步磁阻电机,分析磁障厚度比例对磁阻转矩的影响。进而在优化的同步磁阻电机中间磁障中插入永磁体形成永磁辅助同步磁阻电机,讨论此类永磁辅助同步磁阻电机的齿槽定位力矩、永磁转矩、磁阻转矩和抗退磁性能。最后对比了同步磁阻电机和永磁辅助同步磁阻电机的转矩特性以及调速特性。

轴向叠片各向异性转子同步磁阻电机直接转矩控制的研究

轴向叠片各向异性转子电机具有许多优点,但也存在一些缺点,如起动时需要位置传感器保持转子与磁链同步,电机参数(特别是直轴电感)易受饱和影响而使控制系统复杂等缺点。直接转矩控制具有无位置(速度)传感器,且除定子电阻外不需要其他参数等。介绍了同步磁阻电机控制的研究现状,提出了同步磁阻电机适合使用直接转矩控制技术。通过对四极2.2kWALA转子样机进行的DSP控制实验研究,验证了ALA转子同步磁阻电机直接转矩控制方案的可行性。

基于最小二乘支持向量机逆系统的五自由度无轴承同步磁阻电机解耦控制

针对三自由度交直流混合磁轴承和二自由度无轴承同步磁阻电机构成的五自由度无轴承同步磁阻电机,实现磁轴承的径向悬浮力、轴向悬浮力、二自由度无轴承同步磁阻电机的径向悬浮力和电磁转矩的解耦控制是五自由度无轴承同步磁阻电机稳定运行和精确控制的必要条件。该文在介绍五自由度无轴承同步磁阻电机基本结构的基础上,建立了三自由度交直流混合磁轴承和二自由度无轴承同步磁阻电机的数学模型,进而建立了五自由度无轴承同步磁阻电机的状态方程,并进行了可逆性分析。采用最小二乘支持向量机所具有的小样本逼近和辨识拟合能力,得到五自由度无轴承同步磁阻电机逆模型,根据逆系统方法的基本原理,将复杂的原非线性多变量耦合系统解耦成多个单输入单输出伪线性系统,并设计了闭环PID控制器。仿真和实验表明,电机具有良好的速度和悬浮特性,这种解耦方法能够实现五自由度无轴承同步各个被控量之间的动态解耦,并且系统具有良好的动静态性能。

轴向迭片各向异性转子电机振荡及异步运行分析

轴向迭片各向异性ALA转子电机是 90年代以来得到较快发展的 1种新型磁阻同步电机。在实验研究中 ,发现二极实验电机有振荡及异步运行现象。对此进行了深入的理论分析与探讨 ,揭示出电机转子铁芯 q轴导磁叠片中产生的“单轴转矩”是造成这种现象的根本原因 ,并在简化分析基础上推导出了单轴转矩计算的显式公式。结合实验电机给出了算例 。

同步磁阻电机分析与设计(连载之一)概述

从转矩成分的角度对交流同步电机进行了分类,并针对转矩成分指出了各类电机的特点,从而引出同步磁阻电机的原理。进而比较了同步磁阻电机相比于异步电机、永磁同步电机和开关磁阻电机的优势与劣势,指出了同步磁阻电机替代上述电机的潜在可能和限制因素。综述了增大同步磁阻电机转矩密度、削弱转矩脉动、提高功率因数、减小铁耗和加强机械强度所采用的设计措施。最后根据同步磁阻电机的控制原理分析了其基本控制方式。

考虑磁路饱和同步磁阻电机的矢量控制

同步磁阻电机因无永磁体且具有转矩特性好的特点,得到了越来越多的应用。该电机在运行和控制中d、q轴磁路饱和以及交叉饱和带来的影响较大,为此,论文分析了d、q轴电流对d、q轴磁路交叉饱和的影响,建立了考虑磁路饱和的同步磁阻电机模型,提出了改进的基于磁链观测的同步磁阻电机矢量控制算法,并建立了基于此算法的同步磁阻电机的矢量控制系统,利用所建立的仿真系统和实验系统进行了仿真和实验研究。仿真和实验结果表明,所提出的基于磁链观测的矢量控制算法能够处理同步磁阻电机磁路饱和的影响,提高系统控制的动态性能。

轴向叠片各向异性转子电机磁路分析方法

探讨了轴向叠片各向异性ALA转子电机磁路的分析方法 ,并以实验样机为例 ,计算出电机 q轴磁通在转子导磁叠片中的分布以及磁路磁阻的大小。研究结果对改进转子结构、提高电机动态性能有重要意义。

同步磁阻电机分析与设计(连载之十) 同步磁阻电机与开关磁阻电机定转子的组合应用

将同步磁阻电机的定子与转子及开关磁阻电机的定子与转子分别组合,可形成4种结构形式。采用同步磁阻电机正弦电流的驱动方式,研究4种结构形式电机的性能差异。对比4种结构形式的加工工艺、机械强度、绕组电感和电磁转矩,总结在正弦波电流驱动下,采用同步磁阻电机定转子和开关磁阻电机定转子的优势与劣势。