一种检测无刷直流电机转子位置的新方法

针对传统的无刷直流电机无位置传感器检测转子位置信号需要多级模拟滤波器、复杂的相移电路以及与霍尔传感器输出的信号不一致的缺陷,本文提出了一种通过对三相端电压进行简单滤波、比较后直接获得转子位置信号的新方法.实验结果表明:新方法无需相移,检测的无刷直流电机转子位置信号和采用霍尔传感器输出的位置信号完全一致,可与霍尔传感器所采用的成本低廉的转子位置译码芯片相配套.     

无刷直流电动机转子退磁故障的检测方法

为了研究无刷直流电动机的转子退故障,基于Ansoft/Maxwell软件平台,设置转子退磁故障,建立求解电机反电动势的有限元模型;基于Ansoft/Simplorer软件平台,建立无刷直流电动机系统的仿真模型.在电机稳态运行下,对定子电流进行傅里叶分析,研究并建立基于定子电流监测转子退磁故障的仿真模型:退磁故障与特征频率的关系、退磁故障程度与特征频率幅值的关系.进一步,采用基于转矩常数估计的方法对无刷直流电机的转子退磁故障进行监测.仿真结果表明,在转速波动较小时采用定子电流分析法的效果更好,在转速波动较大时,采用转矩常数估计法可以在线监测无刷直流电动机转子的退磁故障.     

磁阻型无刷双馈电机特殊转子优化设计

在介绍磁阻型转子无刷双馈电机的原理基础上,提出了一种新的具有隔磁桥的径向迭片磁阻转子,并提出了针对该转子进行优化设计的整套流程方法。首先应用改进绕组函数法对电机转子的外形进行设计,然后以电机的转矩最大以及脉动最小为优化目标,利用田口法分别对该磁阻型转子的5个形状参数的4组不同取值进行了分析,根据分析结果选取了最优的一组参数,从而实现了转子结构的优化设计。     

Proposal of two-dimensional magnetic field analysis model for transverse magnetic flux type linear synchronous motor

A three-dimensional model is necessary for the magnetic field analysis of transverse magnetic flux type linear synchronous motors. However, it is unsuitable for design calculation because of the high calculation costs. In order to virtually represent the magnetic path of a three-dimensional arm on a two-dimensional model, we propose the use of virtual arms, which are provided above and below the armature core teeth. In the proposed two-dimensional model, almost the same thrust waveform is obtained with a calculation time of less than 1/30 compared with the threedimensional analysis. The proposed model is also applicable to transverse magnetic flux and longitudinal magnetic flux hybrid type linear synchronous motors.     

Fabrication and excitation testing of a fully superconducting brushless generator with magnetic flux pump

Development of a highly efficient excitation system is important in enhancing the potential of superconducting ac generators. A new conceptual design in which electricity is generated with a brushless exciter system using a superconducting dynamo (the magnetic flux pump) has been proposed. Research on a fully superconducting generator using both a superconducting armature and a superconducting field winding has been under way for the past 7 years. In this paper an experimental model of the machine is described and test results on brushless excitation with the magnetic flux pump, with the machine operating as a fully superconducting brushless generator with an estimated capacity of 20 kVA, are presented. © 1997 Scripta Technica, Inc. Electr Eng Jpn. 118 (4): 35–45, 1997     

电气双余度无刷直流电动机转子极弧系数研究

电气双余度是一种常见的无刷直流电动机(Brushless DC motor,BLDCM)的余度形式.极弧系数直接决定着电气双余度BLDCM的电动势(Electromotive force,EMF)的平顶宽度,而EMF波形对电气双余度BLDCM的电磁转矩波动有着直接的影响;并且极弧系数对电气双余度BLDCM的定位转矩也有着显著的影响.本文针对电气双余度BLDCM,研究了极弧系数对其转矩波动的影响.首先分析了由非理想EMF波形引起的电气双余度BLDCM电磁转矩波动;然后,采用电磁场有限元分析,计算和分析了极弧系数对电气双余度BLDCM的EMF波形和定位转矩的影响;进而得到了有助于减小各种转矩波动的极弧系数取值范围.最后通过示例的计算分析给出了电气双余度BLDCM极弧系数选取的参考方法.     

Electrical characteristics of a fully superconducting brushless generator equipped with a magnetic flux pump

The study of efficient excitation systems is important in order to enhance the potential of superconducting ac generators. We have fabricated a model machine for generating electricity with a brushless exciter system, which consists of a superconducting dynamo or “magnetic flux pump.” A fully superconducting generator in which both armature and field windings are made of superconductors has also been studied. The paper presents power output tests and calculated results on transients as well as the static electrical characteristics of a model machine equipped with a magnetic flux pump when operated as a fully superconducting brushless generator in persistent current mode. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 120 (3): 64–72, 1997     

一种电动自行车用无位置传感器无刷直流电机转子位置检测方法

本文提出了一种用于电动自行车的无位置传感器无刷直流电机转子位置信号的检测方法.本文所有测量电压的参考电位为电源的负母线.高速下通过比较电机的交流虚拟中点与直流虚拟中点,得到反电势的过零点;低速下将电机的交流虚拟中点电压与负母线电位进行比较,得到反电势的过零点.再将反电势的过零点延迟30°电角度即可获得无刷直流电机绕组换相所需要的转子位置信号.该方法具有扩展速度范围的优点.由于不必对检测信号进行滤波,不但省去了滤波电路,同时消除了滤波电路带来的相移问题.文中对该检测方法的原理进行了详细介绍,并通过实验验证了该方法的有效性.     

无速度传感器感应电机改进转子磁链观测器

针对感应电机无速度传感器磁场定向控制系统,提出一种基于电压模型的改进转子磁链观测方法.为了有效抑制反电动势积分环节所存在的直流偏移和积分饱和问题,采用一个截止频率可根据输出频率进行自调整的低通滤波器来代替传统电压模型磁链观测器中的反电动势积分环节.然而低通滤波器的引入将会产生磁链幅值和相位的观测误差,从而导致在低速运行场合中磁链观测性能显著下降,为了解决这一问题,设计一个可以补偿磁链观测误差的补偿器.通过11kW感应电机无速度传感器矢量控制系统对所提出的改进转子磁链观测器进行了实验验证,结果证明了算法的有效性.     

不同转子结构无刷双馈电机转子磁耦合作用的对比分析

介绍了无刷双馈电机的结构特点,描述了多种转子结构型式,研究了不同结构转子的磁耦合和二维瞬态有限元磁场分析软件（ＡＮＳＹＳ）对不同转子结构无刷双馈电机的气隙磁场以及各绕组间的自感和互感磁链进行了对比研究     

新型绕线式转子结构无刷双馈电机的磁场调制机理分析

介绍了一种转子绕组绕线式结构的无刷双馈电机磁场调制原理,分析了电机定子2P和2C极绕组及其在转子绕组中产生磁动势,推导出电机稳定运行条件。对特殊笼形、磁阻式转子结构磁场调制机理也作了介绍,对不同转子结构调制原理进行了对比。     

A synchronous reluctance motor with a laminated rotor

Optimal tooth factors and polar overlap are obtained using numerical calculations of an in-plane magnetic field in the active volume of a synchronous reluctance motor (SRM) with a laminated rotor using FEMM 4.01 (Finite Element Method Magnetics, Version 4.01) software. Recommendations for improving the technical and economic indices of an SRM with laminated rotors at the expense of cutouts in ferromagnetic rotor packs and placing compensatory permanent magnets on the way of transverse magnetic flux closure are given.     

Optimization of the magnetic system of a brushless DC motor with rare-earth permanent magnets

This article discusses the causes of cogging torque pulsations in a deenergized brushless dc motor (BLDC) with a tooth stator and magnetoelectricity stimulation. Based on the causes that we identify, we propose a method of reducing cogging torque pulsations in order to improve the rotation speed uniformity of a BLDC. The method is based on optimization of the number of stator slots, which determines the type of stator winding for a given number of poles in magneto-electric machines. For the maximum possible reduction of cogging torque pulsations, it is proposed to bevel the stator slots at an angle divisible by the main tooth harmonic period. All analytical calculations were performed with the use of numerical methods for mathematical modeling of the magnetic field in the magneto-electric machines with the use of Elcut specialized software. Based on the calculation results, recommendations for the design of a BLDC with a minimum level of cogging torque pulsations were elaborated. Our theoretical studies have been checked by experimental investigations of a DBM 142-18-3 motor and applied to the design of the BLDC (DBM series) manufactured by JSC Electroprivod, Kirov. Electric motors of DBM series are used as precision electric drives for metalworking equipment, where a high uniformity of rotation speed is a major requirement.     

Excitation magnetic flux losses in acyclic motors with transverse magnetization

A theoretical analysis of the distribution of magnetic excitation flux components caused by permanent magnets in acyclic torquer motors with transverse flux magnetization is presented in the article. Magnetic leakage fluxes were assessed by formulas obtained for the computation of said fluxes. Assessments of their impact and recommendations to reduce leakage fluxes in acyclic motors are also given     

矩阵变换器驱动感应电机转矩和转子磁链控制

提出了一种新型的基于感应电机状态方程的矩阵变换器驱动感应电机直接转矩和转子磁链控制方法,将传统直接转矩中的定子磁链控制替换为转子磁链控制,可以得到比传统直接转矩更高的输出转矩.将滑模变结构控制策略引入到矩阵变换器驱动感应电机直接转矩和转子磁链控制中,设计了基于加速度型趋近律的控制律,并直接在静止坐标系下进行运算,不需要传统控制中的坐标变换,采用光滑函数代替常规符号函数,从而达到快速趋近滑模面且具有低抖动的效果.结合矩阵变换器双空间矢量调制方法,并将矩阵变换器过调制方法用于感应电机直接转矩控制中,达到矩阵变换器开关频率恒定和电机快速转矩响应的目的.实验结果验证了该方法的正确性和有效性.     

Radial flux type hysteresis motor with rotor ring of copper-sprayed surface layer

This paper describes a new form of radial flux type hysteresis motor having large output, high efficiency, and high power factor. The rotor has a copper-sprayed surface layer on the rotor ring, which is made of Fe-Cr-Co magnet steel and has magnetic anisotropy and slits. The new configuration has two features. First, it is designed to give a combined hysteresis and reluctance-motor action effectively, particularly at a synchronous speed. Second, it is designed to give a combined hysteresis torque and large torque due to eddy current in asynchronous conditions, particularly at starting. To analyze motor performance at synchronous and asynchronous operations, the finite-element method is used. In this paper, magnetic hysteresis is considered by using complex permeability. The agreement between predicted and measured values of motor performance characteristics is good.     

无刷双馈电机笼型转子结构对磁场调制的影响

无刷双馈电机具有优越的调速性能,且能够运行于变速恒频发电状态,因此在节能调速以及风力发电领域具有很好的应用前景,但其结构和原理比较复杂.为了研究不同笼型转子结构对无刷双馈电机磁场调制作用的影响,从交流电机的基本电磁关系出发,首先分析了定子功率绕组与控制绕组产生的磁动势和气隙磁密,进而导出了转子笼条的感应电动势、电流和磁动势,在此基础上,用实例说明了笼型结构转子磁动势的特点及其对磁场调制作用的影响,最后用有限元计算对理论分析结果进行了验证.理论分析和仿真结果表明,对磁场调制起主要作用的是笼型转子靠近公共笼条的短路环,通过调整转子短路环分布可以增强有效谐波、削弱无用谐波,由此对笼型转子结构进行优化设计.     

A sensorless brushless dc motor system

This paper describes a brushless dc motor system without position or speed sensor. The brushless motor consists of a permanent magnet synchronous motor and a voltage-source inverter capable of controlling the amplitude and frequency of voltage. The rectangular-shaped stator current with a conducting interval of 120° (electrical) is controlled to be in phase with the trapezoidal back electromotive force. This results in producing maximum torque. Variable speed is achieved by adjusting the average motor voltage similarly to chopper control of dc motors. In this paper, two sensorless position detecting methods, i.e., an “indirect method” suited for the lower-speed range and a “direct method” suited for the higher-speed range are proposed. The combination of the two makes it possible to detect the rotor position over a wide-speed range. Furthermore, a speed-sen-sorless PLL control is proposed in applying the principle of the direct method. Experimental results obtained from a prototype brushless dc motor are shown to confirm the validity of the sensorless drive. The starting procedure of the motor also is discussed because it is impossible to detect the rotor position at a standstill.     

Computation of inductance and static thrust of a permanent-magnet-type transverse flux linear motor

This paper proposes an effective method to calculate inductance and static thrust of a permanent magnet (PM)-type transverse flux linear motor (TFLM). The proposed method is a simple and fast way considering three-dimensional (3-D) flux path of the TFLM, and it can be used not only in characteristic assessment, but also in the design process. Two-dimensional (2-D) finite element analysis (FEA) and 3-D equivalent magnetic circuit network (EMCN) analysis are conducted to analyze the magnetic field. The usefulness of the proposed method is verified by comparison with measurement results.