考虑磁路饱和的永磁式同步电机计算

介绍一种考虑到磁路饱和的永磁同步电机转矩和电抗的计算方法。该方法利用有限元法对二维磁场进行数值解析，并给出包含正交磁化现象影响的d、q轴方程式。通过改变转子的位置计算水磁同步电动机的转矩和电抗，给出了转矩和电抗随转子位置变化规律的曲线。实验结果验证了其计算方法的正确性。     

考虑饱和效应凸极同步电动机矢量控制

通过闭环复合磁链观测器,可获得优良的气隙磁链观测效果.基于此,提出一种考虑饱和效应的凸极电机数学模型,利用DSP2812为核心的同步电机实验平台,完成了同步电机矢量控制实验.实验结果表明,基于所提出的气隙磁场定向矢量控制系统具有高性能动静态特性,利用此处建立的饱和数学模型分析和控制同步电机,在磁场饱和非线性时,同步电机...     

考虑磁饱和影响的同步发电机励磁电流计算

在考虑同步发电机磁路饱和效应的基础上,提出了发电机励磁电流计算的数学模型.该模型涉及发电机的空载特性曲线、保梯电抗和磁路磁链方程,计算过程比较简便、实用.对于不计饱和特性、直接采用饱和电抗以及采用定子漏抗替代保梯电抗的三种情况分别进行了励磁电流计算,以发电机V形曲线的形式比较了该模型与这三种情况下的计算结果差异,经多台发电机励磁电流的计算和实际测试,验证了该模型的有效性和实用性.     

考虑铁心饱和的内置式永磁同步电机气隙磁场解析计算

准确分析电机结构以及磁饱和等因素对气隙磁场分布的影响是永磁电机设计、优化的关键。以分数槽集中绕组内置式永磁同步电机(FSCW-IPMSM)为研究对象,根据磁路分析方法和FSCW的分布规律,分别得到了考虑转子磁桥漏磁的空载永磁磁场解析模型和电枢反应磁场的解析表达式。考虑到定子齿槽结构以及转子内部永磁体分布,利用相对气隙磁导,将定子开槽和转子凸极对气隙磁场的影响考虑在内。重点结合定子铁心材料的B-H磁化曲线、定子铁心局部磁饱和特性引入铁心等效磁阻与动态磁导率来考虑定子铁心磁饱和对负载气隙磁场的影响。最后,有限元仿真和样机试验结果验证了理论分析的准确性,为该类电机的电磁设计和性能分析提供了理论基础。     

交直流混合供电的多相电机稳态电抗的测定

研究了交直流混合供电的多相电机对称稳态电抗的测定 ,导出了有关计算公式 ,并在一台交直流混合供电的三相 /十二相电机上测出了其稳态电抗值 ,利用稳态电抗的测试值 ,对电机进行了计算机仿真分析 ,仿真结果较好地吻合了实际样机的试验结果 ,验证了所测参数的正确性。     

计及磁饱和的车用永磁同步电机MTPA控制技术

永磁同步电机具有较高的效率和功率密度,在电动汽车驱动系统中广泛应用。电机的d、q轴电感是设计控制系统的重要参数,但重载情况下受磁饱和及交叉饱和影响严重。传统控制技术忽略磁饱和效应,导致转矩控制的精确性不足。采用有限元法分析电机负载时的磁饱和情况,计算考虑磁饱和及交叉饱和的d、q轴电感参数。以此为基础,拟合d、q轴电感和电流关系。设计计及磁饱和的最大转矩电流比MTPA(maximum torque per ampere)控制,使d、q轴参考电流计算中使用的电感随电机电流变化。通过对比,证明计及磁饱和的MTPA控制能够实现输出转矩的精确控制,提高永磁同步电机的动态响应性能。     

基于改进静止频率响应试验的同步电机参数辨识

针对同步电机参数辨识问题,以全电流为状态变量,研究同步电机d、q轴磁链与定子电流及励磁电压的关系,建立电机的数学模型。通过分析静止频率响应试验曲线,获得不同频率下各测试参数的增益和相位,替换d、q轴电磁参数特性传递函数方程中的相关部分,简化电机数学模型及其状态空间方程。基于励磁和定子回路开路时电机状态的分析结果,改进数据处理过程,辨识电机参数,对比采用其它方法测取的结果,有较好的一致性,所提参数辨识方法的有效性得以验证。     

Calculation of the Characteristics of Salient‐Pole Synchronous Machines Assisted by Permanent Magnets on the Basis of the Operating Principle

In this study we investigate a method for accurately calculating the characteristics of salient‐pole synchronous machines assisted by permanent magnets. First, the operating principle of the machines is investigated by using both finite element analysis and a simple magnetic circuit. Then, a theoretical representation of the assist effect on the permanent magnets is derived based on the magnetic circuit. Finally, the measured and calculated results are compared in order to confirm the validity of the proposed calculation method. We show that the load characteristics of the proposed machine can be accurately estimated from the no‐load and short‐circuit characteristics of the conventional machine without permanent magnets, and the size and magnetization of the inserted permanent magnets.     

Magnetic field analysis of a 70‐MW‐class superconducting generator by the 3D finite element method

The three‐dimensional magnetic field and eddy current distribution of the 70‐MW‐class superconducting generator was calculated by a finite element method. The condition for the exciting armature coil was calculated by the jω‐method. In the magnetic flux distribution of the armature winding bore, the value obtained by analysis had good agreement with the measurement. An analysis that let the rotor move by the synchronizing speed was also done. The armature voltage for the nonload condition and the armature current for the three‐phase short‐circuit condition obtained by calculations had good agreement with the measurements. The validity of the analytical model for three‐dimensional magnetic field analysis of superconducting generators was confirmed from these results. In addition, the synchronous reactances were calculated using these results with eddy current in the facing. It was found that the facing had the effect of decreasing synchronous reactance by about 5%. © 2000 Scripta Technica, Electr Eng Jpn, 134(2): 53–60, 2001     

Analysis of Eddy‐Current Losses in Solid Iron Under dc‐Biased Magnetization Considering Minor Hysteresis Loops

In designing solid‐pole synchronous machines, it is important to take into account the surface eddy‐current losses in the field pole cores. In this study, a solid‐iron ring specimen is adopted as an approximate model of solid‐pole surfaces in order to conduct a fundamental study of the surface losses. The influence of the minor hysteresis loops on the losses under dc‐biased magnetization is investigated. The losses in the ring under dc‐biased magnetization are measured and analyzed by finite element analysis (FEA). The losses computed by the FEA considering minor loops are nearly the same as those measured. In contrast, the eddy‐current losses computed by FEA without considering minor loops are considerably inaccurate because the incremental permeability is overestimated and the skin depth is underestimated. It is important to consider hysteresis for the accurate calculation of the surface eddy‐current losses under dc‐biased magnetization.     

New Dynamic Self‐Consistent Mathematical Model and Torque Characteristics of Permanent‐Magnet Synchronous Motors with Magnetic Cross‐Coupling

This paper proposes a new dynamic mathematical model of permanent‐magnet synchronous motors (PMSMs) with magnetic cross‐coupling and presents a new analysis of the torque characteristics of the motors. Generally speaking, dynamic mathematical models used for the design and analysis of PMSM control systems must consist of three basic equations that describe the main motor characteristics as an electrical circuit, torque generator, and electromechanical energy converter. In order to obtain reasonably compact models, some characteristics have to be approximated. However, in the case where the approximations used in the three basic equations are different from each other, the dynamic mathematical model often loses self‐consistency and becomes self‐contradictory. The proposed model, which takes the magnetic cross‐coupling into account, is self‐consistent and compact, and its effectiveness is validated by experimental data. Using the self‐consistency and compactness, this study presents a new analysis of the torque characteristics of PMSMs, focusing on efficient torque generation. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(1): 42–55, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22382     

Magnet design and motor performances of a double‐layer interior permanent magnet synchronous motor

In this paper we discuss the results of our investigation of the interior permanent magnet synchronous motor (IPM), with permanent magnets embedded in the rotor, and particularly the double‐layer IPM synchronous motor, which has two layers of magnets embedded in the rotor, layered in the radial direction. For this investigation, we studied the arrangement of permanent magnets both through simulation and by experiments with a prototype. The results concerning the form of the magnets clearly show the advantages of the reverse arc configuration, which makes it possible to increase the surface area creating magnetic flux. We further determined that to maximize both the q‐axis flux and the flux of the permanent magnets, the optimum width of the q‐axis flux path between the magnets for the motor investigated here is 2 mm. The results also clearly show that chamfering the ends of magnets is effective in achieving better utilization of the q‐axis flux.© 1999 Scripta Technica, Electr Eng Jpn, 128(1): 62–69, 1999     

考虑漏磁效应的永磁饱和型故障限流器磁路建模与实验研究

漏磁效应对永磁饱和型故障限流器(permanent-magnet-biased saturation based fault current limiter,PMFCL)的动态特性具有重要影响。针对一种直线式PMFCL的磁拓扑,以铁心磁通的工作零点作为分界阐明了其2个阶段的限流机理,指出铁心磁通自过零反向后将发生畸变,永磁体不再参与限流过程。基于磁场分割原理实现2类等效磁路模型中总漏磁导和漏磁系数的计算,针对拟圆环截面磁通管的漏磁导,提出基于曲线拟合而改变积分变量的求解方法。在Matlab/Simulink环境下建立了考虑漏磁效应的PMFCL仿真模型,分别与小电流和大电流工况的实验结果进行对比,验证了建模方法的有效性。     

Determination of equivalent circuit constants of synchronous machines from the extended Dalton‐Cameron method

This paper presents a method of determining the equivalent circuit constants which accord with the physical construction of synchronous machines, using the dc decay testing method with the rotor in arbitrary position (proposed by the authors and called the extended Dalton–Cameron method). The conventional Dalton–Cameron method calculates the direct‐ and quadrature‐axis subtransient reactance from a standstill response test in any arbitrary rotor position using a single‐phase power supply. The extended Dalton–Cameron method determines the direct‐ and quadrature‐axis operational impedances for each slip from a standstill response test using a small‐capacity dc power supply. The direct‐ and quadrature‐axis operational impedance loci thus obtained synchronous machine constants (subtransient, transient, and synchronous reactances) are used to estimate the direct‐ and quadrature‐axis equivalent circuit constants which accord with the physical construction of synchronous machines. As an example, equivalent circuit constants are determined for a 10‐kW laminated salient‐pole‐type synchronous machine with damper winding. The validity of the equivalent circuit constants is confirmed by comparing the calculated resistance and leakage reactance of the field winding determined from the operational impedance when the terminals are short‐circuited, to those when the terminals are connected to an external resistance. © 2001 Scripta Technica, Electr Eng Jpn, 138(1): 56–67, 2002     

The influence of mistuned motor parameters on vector control performance and on line slip frequency correction strategy for induction machine operated under one‐pulse PWM mode

In high‐power, high‐speed traction drive systems, the traction motor usually operates under one‐pulse PWM (pulse width modulation) mode (square wave) during high‐speed operation. The constant output voltage in this condition makes the traditional vector control inoperative anymore. In this paper, a modified vector control strategy using open‐loop current control instead of closed‐loop current control is proposed. The modified control strategy is specially designed for an induction motor operating under one‐pulse PWM mode. As the field orientation is greatly affected by the deviation in the parameters, the influence of mistuned rotor time constant and mutual inductance (which are regarded as the most important parameters for field orientation) on the performance of modified vector control is studied comprehensively, including the influence on estimated angle and amplitude of rotor flux, d/q‐axis voltage, and output torque. Subsequently, based on the comparison between the different methods, a new slip frequency correction strategy is proposed to maintain proper field orientation for the modified vector control. The new correction strategy is based on the q‐axis current component error. It is independent of the motor parameters and can be easily realized through minor calculations. The simulation and experimental results show that the proposed slip frequency correction strategy can not only eliminate rotor flux angle error in steady state but also effect rapid torque response during the transient process under one‐pulse PWM mode. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.