正弦PWM 电压源逆变器供电的永磁直线同步电机低速负载性能.docx

1、摘 要对于开环低速区由正弦PWM电压源逆变器供电的永磁直线同步电机（PMLSM）而言，与工作在高速情况的PMLSM 负载性能不同，本文采用场路耦合时步有限元的方法研究PMLSM驱动水平运输系统的两种负载工况：轻载与重载。结果显示，PMLSM 工作在重载情况下的负载性能较轻载优，且电机的工作电流随着负载的增大而减小。仿真与实验结果验证了该方法的有效性及正确性。关键词：永磁直线同步电机，负载性能，正弦PWM，电压源逆变器，时步有限元法，场路耦合1 引言永磁直线同步电机（PMLSM）已广泛应用于多种领域，因为该电机具有高效性、高精度的控制性等特点,从自动化的运输操作系统到复杂精细的军事设备都会运用到

2、它。然而，对于在较低速情况下的PMLSM的负载性能的研究是非常必要的，并且同步旋转电机和PMLSM在高速情况下也有很多不同的特征。PMLSM在低速情况下因为有多而有效的气压和低频率，电机具有抗电感能力强的基本特性。很多PMLSM具有这些特性，因为适用于PMLSM的转速和频率是有限的。通过文献【5】可以得出，适用于PMLSM的规格是一样的。电机的运转频率是6HZ，磁极距必须是30毫米。时步有限元分析法的研究为正弦PWM电压源逆变器供电的电机驱动作了依据，并且由于PWM电压源逆变器，人们对于时间步长的价值观也改变了。在文献【6】中，作者在边缘效应的基础上描述了激励永磁同步电机的部分动态性能。对于P

3、MLSM驱动的启动和控制的相关方面已经有所研究。电机规格也是一样的。电阻是7.6，电感是17.6mH，最大转速是2m/s。根据文献【7】显示可知，模拟电压是7V，频率是3Hz，负载驱动力是20N。电压源逆变器供电的PMLSM的动态特性的滞后性，是考虑了在合成铝板和固体回收铁中的涡电流，并通过分析时步有限元法和无线网络技术得出的。在文献【3】中，适于PMLSM的规格如下。电阻是5.2，电感是2.8mH，电机驱动的转速是0.9m/s。文献【8】已经呈现出PMLSM基于正弦交流电流源，如大电感和电阻率，的稳态性能。但是，对于在低频率下的有大的电阻率和电感、半导体的SPWM逆变器操作，动态性能指标的研

4、究在上述文献中比较缺乏。因此，研究电机在不同负载下的动态性能是极其重要的。最近，通过精确的磁场分析，已经研究提出了电机的动态性能。其中的一种数学方法是基于有限元法的方法，它被越来越多的应用于精确探讨不对称磁场的动态性能。至于PMLSM，它有三相不平衡绕组、开放磁路、电阻率、电感系数、相位、谐波和电机电流。采用解析法和传统的有限元法客观地研究一个或两个极点的周期边界条件，是很困难的，另外考虑到连接外部SPWM变频器和磁场的问题，因此，本文就采用有限元分析法研究电机在不同负载的情况下，其暂态过程的性能，如：推力、移动速度和绕组电流。由于PMLSM靠SPWM电压源逆变器供电，电机的电流是不知道的，并

5、且电机的电压还包括许多谐波分量，这就使有限元分析法不是很理想了。因此采用研究负荷性能时步有限元法和场耦合法就可以很好的研究该系统。这篇文章提出了使用时步有限元法和场耦合法研究电机在不同负荷情况下的性能。以下将会系统的讲解，在第二部分中，将对永磁交流同步直线电机进行描述。有限元模型在第三节中讲解。在论文第四部分将会研究PMLSM在不同负载下的性能并进行仿真和总结。在第五和第六部分，就总结实验结果并总结结论。2 物理分析模型这个模型主要是由三相绕组和核心扩展插槽组成，其次是由永久性磁铁和在铁轭表面上分离出来的磁性组成。PMLSM的规格如下表1所示。其中含永磁磁铁磁化的漏磁量等。PMLSM的性能规格

6、就在下面的表格中。PMLSM 规格表 型材 项目 材料和单位 相位 3 匝数 90主要 电枢材料 铁 磁极距 39mm 槽距 13mm 主存材料 永久性磁铁 宽度 27mm 其次 高度 7mm 长度 120mm 镶嵌 表面型 空隙 5mm 图1 物理模型的方法建立的永磁直线型同步电机主要部分 2齿轮 3开槽 4绝缘磁铁材料 5永磁铁 6铁轭3 PMLSM励磁电路的数学模型把SPWM电压源逆变器，电机边缘效应影响因素考虑进去，采用励磁电路方法计算电磁的暂态方程，解决向量电磁场的变化过程及电机的稳态方程，由励磁电路相结合的电磁场时步有限元方程，并说明在电枢绕组中的绕组电路电动势方程。瞬变场的控制方

7、程，电磁场是可变的，其依据是麦克斯韦方程式。如方程式（1）可示：式中,Az向量电磁场中z轴方向的分量 Js电流密度Jm磁化密度磁导率在摘要中，2-d模型可以被分为三角元素构成网孔。在运用伽辽金法后，运动方程的分析模型为：式中，A未知的潜在向量电磁场 I绕组电流 S,C,T系数 G等效的矩阵磁化电流密度 在外磁场作用下，磁介质磁化后出现的磁化电流要产生附加磁场。等效磁化法被用来处理永磁型场。磁化强度的符号是M0.由于电机较大的空隙特点，PMLSM的电阻和漏磁电抗没有被忽视。根据欧姆定律和法拉第电磁感应定律，关于电动势和电压的产生的三相绕组式如方程【4】：其中 感应电动势 Ll自感系数 R线圈电阻

8、 U线圈电压其中 N有效的线圈匝数 B磁通密度 S1有效面积 S2有效面积适用于PMLSM的磁路和电路是不平衡的，从而固定连接器的电势不等于零域上的电势。因此电机的相位方程修改如下：其中 U0逆变器的输出电压 g0逆变器开关功能 Ud直流电压采用麦克斯韦法计算PMLSM的电磁力，其中包含了所有种类的谐波成分。电机电磁力的正弦分量计算载于公式（9）。电机电磁力的垂直分量计算载于公式（10）。其中 L1绕组的有效长度 L2积分长度 Bxx轴方向的磁通密度 Byy轴方向的磁通密度 FT正弦方向上的电磁力 FN垂直方向上的电磁力PMLSM的运动方程如下：其中 m质量 v速度 FL负荷重力4 仿真结果仿

9、真结果图形如下。恒定电压是30V，模块频率是2Hz，轻负载是50N，重负载是130N，电机额定同步速度是0.156m/s，这与PMLSM实验模型的参数是保持一致的。从仿真结果我们可以得到，空间磁场的功能元素及外部电路的状态作用。由于靠电压逆变器提供电压，外部条件可以忽略不计。图2是在50N负载下的三相电流的仿真图形。图3是驱动力。图4是在50N负载下的速度。图5图7是在130N负载下的仿真图形。从图2和图5，我们可以看出在50N负载下的三相电流比在130N负载情况下的要大。因为PMLSM的磁路电枢绕组是开放的，不连续的。比较图3和图7，我们可以看出PMLSM在130N负载下的驱动力更大。在图4

10、和图7中可以看出，在130N负载的情况下，电机的性能更好，更稳定。如果产生的适用于PMLSM的磁阻力减少，移动速度基本上是接近同步速度的，因为有许多谐波，速度要完全相同是不可能的。（a阶段，b阶段，c阶段）图2 在50N负载下的三相电流图3 在50N负载下的驱动力图4 在50N负载下不减少磁阻力时的速度图5 在130N负载下的三相电流图6 在130N负载下的驱动力图7 在130N负载下的速度5 实验结果电压和电流是通过传感器来检测的。速度是通过E6B2型号的旋转编码器测得的，这个转速可以转化为电机的直线速度。数据采集系统可以通过Turbo C来编辑。图8和图11分别是在50N和130N情况下的

11、三相电流。图9和图12是分别在两种负载下的驱动力。图10和图13是在这两种负载下的速度。通过仿真和实验结果，我们可以看出，这两种情况都是可以的。图8 在50N负载下的三相电流图9 在50N负载下的驱动力图10 在50N负载下的速度图11 在130N负载下的三相电流图12 在130N负载下的驱动力图13 在130N负载下的速度6 总结在上述内容中，励磁电路耦合法中的时步有限元法和外部电路被用来分析专门适用于永磁交流同步电机在大阻力、大电感、大气隙和三相不平衡的低速度的情况下的负载性能。分析结果表面，PMLSM在重载情况下的负载性能比轻载时好，并且电机的工作电流随着负载的增大而减小。由于止动装置的

12、存在，PMLSM产生磁阻力的波动，同步转速范围的移动速度。如果引起的适用于PMLSM的开环控制的磁阻力降低，转动速度将相当接近于同步速度。参考文献1 Wang Xudong, Yuan Shiying, Jiao Liucheng, et al.3-D analysis of electromagnetic field and performance in a permanent magnet linear synchronous motorC. IEEE International Electric Machines and Drives Conference, Cambridge, MA

13、USA, 2001: 935-938.2 Bianchi N. Analytical computation of magnetic fields and thrusts in a tubular PM linear servo motorC. Conference Record-IAS Annual Meeting (IEEE Industry Applications Society), Rome, Italy, 2000, 1: 21-28.3 Bon Gwan Gu, Kwanghee Nam. A vector control scheme for a PM linear synch

14、ronous motor in extended regionJ. IEEE Transactions on Industry Applications, 2003, 39(5): 1280-1286.4 Gore V C, Cruise R J, Landy C F. Considerations for an integrated transport system using linear synchronous motors for ultra-deep level miningC. IEMD 99, Seattle, Washington, USA, 1999: 568-570.5 J

15、ung In Soung, Hyun Dong Seok. Dynamic characteristics of PM linear synchronous motor driven by PWM inverter by finite element analysisJ. IEEE Transactions on Magnetics, 1999, 35(5): 3697-3699.6 Sang Yong Jung, Hyun Kyo Jung, Jang Sung Chun, et al. Dynamic characteristics of partially excited permane

16、nt magnet linear synchronous motor considering end-effectC. IEEE International Electric Machines and Drives Conference, Boston, USA, 2001: 508-515.7 Kwon Byung Il, Woo Kyung Il, Kim Duck Jin,et al. Finite element analysis for dynamic characteristics of an inverter-fed PMLSM by a new moving mesh tech

17、niqueJ. IEEE Transactions on Magnetics, 2000, 36(4): 1574-1577.8 Shangguan Xuanfeng, Li Qingfu, Yuan Shiying. Analysis on characteristics of permanent magnet linear synchronous machines with large armature resistance and small reactance C. The Eighth International Conference on Electrical Machines a

18、nd Systems, Nanjing, China, 2005, 1: 434-438.9 Tounzi A, Henneron T, LeMenach Y, et al. 3-D approaches to determine the end winding inductances of a permanent-magnet linear synchronous motorJ. IEEE Transactions on Magnetics, 2004, 40(2): 758-761.10 Yamaguchi T, Kawase Y, Yoshida M, et al. 3-D finite

19、 element analysis of a linear induction motorJ. IEEE Transactions on Magnetics, 2001, 37(5): 3668-3671.11 In Soung Jung, Sang Baeck Yoon, Jang Ho Shim, et al. Analysis of forces in a short primary type and a short secondary type permanent magnet linear synchronous motorJ. IEEE Transactions on Energy

20、 Conversion, 1999, 14(4): 1265-1270.外文原文资料信息1 外文原文作者：Si Jikai Chen Hao Wang Xudong Yuan Shiying Shangguan Xuanfeng2 外文原文所在书名或论文题目：LOAD PERFORMANCE OF PMLSM IN LOWER SPEEDREGION FED BY SINUOIDAL PWM INWERTER3 外文原文来源：TRANSACTIONS OF CHINA ELECTROTECHNICAL SOCIETY文献翻译原文LOAD PERFORMANCE OF PMLSM IN LOWE

21、R SPEEDREGION FED BY SINUOIDAL PWM INVERTERSi Jikai1,2 Chen Hao1 Wang Xudong2 Yuan Shiying2 Shangguan Xuanfeng2（1. China University of Mining and Technology Xuzhou 221008 China2. Henan Polytechnic University Jiaozuo 454000 China）ABSTRACTFor the permanent magnet linear synchronous motor (PMLSM) fed b

22、y sinusoidal PWM voltage source inverter in the lower speed condition without feedback control, load performance isdifferent from the PMLSM working in high speed region. The paper adopts time-step finite elementmethod and field circuit coupling method to investigate load performance of the PMLSM to

23、drive horizontal transportation system with light load and heavy load condition respectively. It is shown that load performance of the PMLSM in the heavy load condition is highly better than those in light load operation conditions, and operation current becomes lower with load increasing. The valid

24、ity is verified by comparisons of simulation and experimental results.Keywords: Permanent magnet linear synchronous motor (PMLSM), load performances, sinusoidal,PWM (SPWM) inverter, time-step finite element method, field circuit coupling method1 IntroductionThe permanent magnet linear synchronous mo

25、tor(PMLSM) has been widely used in many applications from transportation system to office automation and military devices because the motors have lots of merits as high efficient, high accuracy position control, etc1-4. However, it is necessary that load performance of lower speed of PMLSM is profou

26、ndly researched, which has lots of characteristics to different from rotating synchronous machine and PMLSM in the high speed region. PMLSM in lower speed region has the essential characteristics that there are large ratio of the motor resistance to inductance and large leakage inductance because of

27、 large and effective air gap and lower operation frequency. Lots of PMLSMs have the characteristics because the moving track of PMLSM is limited and the mover steady state running speed of PMLSM is finite. In the Ref.5,specifications of PMLSM were as follow. The motor operation frequency was 6Hz, th

28、e pole pitch was 30mm. In the literature FEA method for electric machines driven by PWM inverter was proposed and the value of time-step was changed according to theswitching logic of PWM inverter. In the Ref.6, the authors presented the dynamic characteristics of partially excited permanent magnet

29、linear synchronous motor considering end-effect. The starting and control characteristics related to the capability in PMLSM driving were investigated. The specifications of the motor were as follow. The resistance was 7.6 of sample A, the inductance was 17.6mH, the maximum speed was 2m/s. As the Re

30、f.7shown, the simulation condition was 7V, 3Hz and load thrust was 20N. The dynamic characteristics of the hysteresis current controlled inverter-fed PMLSM with the conductive sheet secondary was analyzed through the time-step finite element method and moving mesh technique, which considering eddy-c

31、urrents in the secondary aluminum sheet and solid back iron. In the Ref.3, the specifications of PMLSM were as follows. The resistance was 5.2, the inductance was 2.8mH,the motor was running at 0.9m/s. Ref.8 had presented the steady-state performance of PMLSM based on sinusoidal ac current source su

32、ch as larger ratio of resistance and inductance, and the mover in and out the primary. Unfortunately, as for the PMLSM fed by SPWM inverter operated in lower operation frequency region with larger ratio of resistance and inductance and larger leakage inductance, the study of dynamic performance is p

33、oor in above-mentioned literatures and it is important to investigate the motor dynamic performance in difference loads conditions.Recently, many numerical methods have been proposed to investigate motors dynamic performance through accurate magnetic field analysis. One of the numerical methods base

34、d on the finite element method, which is more and more used to accurately investigate dynamic characteristics of specify and new machines structures or asymmetry magnetic field, can consider geometric details and the nonlinear of magnetic circuit9-11. As for PMLSM, it has threephase windings unbalan

35、ce, magnetic circuit opening, bigger ratio of resistance and inductance of the phase windings, and time harmonic for the motor current existence. It is difficult to study the motor performances adopting the analytical method and the conventional FEM with objective of one or two poles considering per

36、iod boundary conditions, additionally considering the linkage questions of outer SPWM inverter and magnetic field, thus, the paper uses total model of the motor FEA to attain transient process performances such as thrust, the mover speed and windings current in different load conditions. Due to the

37、PMLSM fed by SPWM voltage source inverter, the currents of the motor are unknown and voltage includes lots of harmonic components, the effect of using one tool of finite element method is not ideal. Thus time-step finite element method and coupling field circuit method is adopted to investigate load

38、 performances of the motor driving horizontal transportation system. The paper presents simulation tools, which using time-step finite element method and field circuit coupling method and experiment to investigate the motor performances in two loads conditions, light load and heavy load. The paper i

39、s organized as follows. In section , the prototype PMLSM is described. FEM model is established in section . Insection simulation results of PMLSM load performances are attained and discussed. In section experimental results are presented. Lastly, in section some conclusions are drawn.2 Analysis mod

40、elThe primary is composed of three-phase windings and core opened slot, and the secondary consists in permanent magnets and the separated magnetism piece which placed on the surface of the iron yoke. Single side type short primary and surface mounted PMLSM are shown in Fig.1, in which permanent magn

41、et magnetization is unanimous to air gap flux axis, leakage flux in poles interval lower and craftwork simple. The specifications of PMLSM are shown in Table.Table PMLSM specificationsFig.1 Physical model of surface permanent magnet linear synchronous motor1 The primary 2Tooth 3Slot 4Material of ins

42、ulating magnet 5Permanent magnet 6The secondary yokeTo take circuit fed by SPWM voltage source inverter and the motor end effects into account, the paper adopts field-circuit coupling method to calculate electromagnetic transient process, solve equation variables of magnetic vector potential and the

43、 motor phase current, which are combination of electromagnetic field time-step finite element Equ. and threephase windings circuit equations. by electromotive force in the armature windings. Transient field governing equations. in which Az denotes magnetic vector potential is variable are shown in E

44、q.(1) according to Maxwell equationswhere Azz-axis component of magnetic vector potentialJsCurrent density of the primary windingsJmEquivalent magnetizing surface current density of permanent magnetThe permeabilityIn the paper, the 2-D model is subdivided into small triangle elements to form a mesh

45、that covers the entire region adopting n-order unit basic function and linear interpolation. After applying the Galerkin method, thegoverning equations. for the analysis model is expressed aswhere AUnknown magnetic vector potential (A is used in Eq.(1) with different meaning)ICurrent in the windings

46、S,C,T Coefficient respectivelyG Corresponding matrix of equivalent magnetization current densityEquivalent magnetizing surface current method is adopted to deal with NdFeB type permanent magnet, which is uniformity magnetization, regulation shape, and linear demagnetization. Intensity of magnetization sign is M0.PMLSM resistance and leakage