盘式永磁电机的分数槽绕组齿槽转矩分析

由齿槽转矩造成的推力波动是影响盘式永磁电机运行性能的一个重要因素.为削弱齿槽转矩,采用基于能量法和傅里叶分解的解析分析方法推导出了齿槽转矩解析表达式,在此基础上研究了分数槽绕组对齿槽转矩的削弱作用,结合定子槽口宽度对齿槽转矩的影响,提出了减少盘式永磁电机齿槽转矩的优化方案,并利用有限元法对此优化方案进行了仿真分析和验证.研究结果证明,采用分数槽绕组和槽口优化相结合的方法能有效地削弱盘式电机的齿槽转矩.     

EPS永磁无刷直流电动机齿槽转矩抑制方法

文章建立了快速分析永磁无刷直流电动机齿槽转矩的数学模型,分析了多种抑制齿槽转矩的方法,并提出了一种有效降低永磁无刷直流电动机齿槽转矩的全新转子结构,给出了齿槽转矩的计算波形,比较了直槽直极和分瓣斜极两种转子结构下齿槽转矩的大小,验证了这种方法的有效性。     

压缩机用无刷直流电机的设计与研究

针对电机的性能要求指标,根据电机电磁设计方法来确定电机的主要尺寸。无刷直流电机的转矩波动会引起电机的振动、产生电机噪声,从而影响电机的性能。齿槽转矩是引起电机转矩波动的重要因素,基于Maxwell建立该电机的二维模型,对其进行有限元分析,并利用不等厚永磁体的方法来降低该电机的齿槽转矩。最后通过Maxwell仿真对比,验证降低齿槽转矩方法的可行性。     

基于极弧系数组合的永磁直线电机齿槽力削弱方法

永磁电机由于齿槽效应造成的推力波动一直是影响其性能的一个重要因素.为了削弱永磁同步直线电机的齿槽转矩,结合直线电机的结构特点,利用能量法和傅立叶分解的解析分析方法,推导出了齿槽转矩与极弧系数的数学关系表达式.由于边端力也会造成直线电机的推力波动,而边端力与动子长度密切相关,提出了一种基于不同极弧系数组合的齿槽转矩削弱方...     

定子铁心混合叠压再制造电机的齿槽转矩分析

为提高再制造电机的性能,用非晶材料与硅钢材料混合叠压制成再制造电机定子铁心。基于能量法并结合定子混合叠压再制造电机的结构特征,提出以分段叠加算法近似替代三维计算定子混合叠压电机齿槽转矩的方法;基于近似叠加算法,利用分段设置反向斜槽的方法来减小齿槽转矩。应用Ansoft 3D软件分析了混合叠压方式对电机齿槽转矩的影响规律;对比分析了不同混合比例下电机的性能参数,确定了混合叠压的材料比例;对确定混合比例下正反斜槽后电机的齿槽转矩与空载电动势进行了分析。结果表明,定子混合叠压再制造电机的齿槽转矩与叠压方式无关,只与所用材料的比例有关;反向斜槽相比于正向斜槽,在有效减小齿槽转矩的同时,对电机性能的影响较小。将混合仿真与叠加计算结果进行对比,验证了二维叠加近似计算混合叠压的可行性。     

无刷直流电机矢量控制策略与实现

针对无刷直流电机采用传统驱动控制方式存在的电能利用率低、转矩脉动大、噪声高等问题,分析了电机出现这些现象的原因,给出了一种基于矢量控制正弦波驱动无刷直流电机的控制方法,并研制了磁场定向控制无刷直流电机控制系统。该系统以STM32F103VE控制器为核心,设计了逆变驱动、过压过流检测与保护等硬件电路,并给出了软件控制策略。实验结果表明,与传统的方波换相方式相比,矢量控制可使换相电流波动下降52%,降低了电机的转矩脉动和运行噪声,适用于如空调、抽油烟机等对运行噪声比较敏感的设备,有较高的应用价值。     

控制棒驱动机构用同步磁阻电机低速运转平稳性研究

首先通过分析控制棒驱动机构中同步磁阻电机在低速运行时出现失稳的原因,得到了齿槽转矩脉动、换相换流转矩脉动和低速时电流非正弦引起的转矩脉动对转矩波动的影响规律.然后通过建立的低速运转仿真模型得到了电机在不同转速下的电流和输出转矩,并针对仿真结果,提出了从电机本体结构和控制方式对电机转矩脉动进行优化的方案.仿真结果表明:优化后电机低速运行平稳性得到明显改善,在低速运行时的电流畸变率减小了65%,转矩脉动最高减小了81%.     

小型力矩电机波动力矩的测量

综合考虑现有无刷直流力矩电机波动力矩动静态测量方法的不足,提出了一种精确测量力矩电机波动力矩的方法。分析了力矩电机波动力矩经典测量方法的误差来源,根据力矩电机分体式的结构特点和可以长期堵转的性能特点,提出了采用电机定子相对转子旋转测量波动力矩的方法。在力矩电机转子堵转的状态下,通过外力旋转定子,测量电机堵转力矩的波动值,从而有效减少测量过程中惯性力矩和摩擦力矩引入的误差。根据提出的测量方法搭建了一套波动力矩测量装置,使用蜗轮蜗杆机构实现了定转子的相对旋转,并对测量装置进行了校准实验。实验结果表明,对于量程为0~1Nm的装置,其测量准确度可达0.3%,线性度为0.1%,基本满足无刷直流力矩电机对波动力矩测量的精度要求。     

抑制永磁同步电机转矩脉动的转子再设计方法

为抑制再制造永磁同步电机的转矩脉动,提出了单一极内偏心槽、组合偏心槽、磁桥优化的递进再设计方法。以车用JEEMC01003B型永磁同步电机为研究对象,解析了单一极内偏心槽和组合偏心槽对齿槽转矩和谐波转矩的影响。在此基础上进行了磁桥再设计,综合优化了转矩脉动。研究结果表明：与原电机相比,再制造电机的转矩脉动减小了3%,平均转矩增大了0.2 N·m,齿槽转矩减小了6%,铁耗减少了4.7 W/kg,磁密畸变率降低了5.6%,效率提高至97.60%,电机性能明显得到提升。     

Analysis of the magnetic force and the torque in a brushless DC motor

As permanent-magnet motors and generators produce torque, vibration occurs through the small air gap due to the alternating magnetic forces created by the rotating permanent magnets and the current switching of the coils. The magnetic force can be calculated from the flux density by finite element methods and the Maxwell stress tensor in cylindrical coordinates. The transition of the magnetic force with the rotation of rotor and the commutation of current, was analyzed by assuming the quasi static magnetic field. The cogging and the commutating torques were also investigated by integrating the magnetic shear force in a small air-gap. In addition, the characteristics of these forces and torques were also investigated by multi-dimensional spectral analysis, so that this paper makes it possible to predict the frequency spectrum of magnetic force and the torque in a brushless do motor.     

Simulation analysis of cogging torque of permanent magnet synchronous motor for electric vehicle

This paper proposes a new approach to study generation mechanism and influence factors of cogging torque of permanent magnet synchronous motors, in order to improve the operational performance and riding comfort of electric vehicle. Based on energy method and Fourier expansion, the method of predicting cogging torque is proposed. Two-dimensional finite element model of in-wheel motor is established by Maxwell software, and electromagnetic character of that is analyzed. Skew slot, pole arc coefficient and width of slot mouth are analyzed and studied by finite element method, in order to realize the change regularity of cogging torque. Cogging torque curves under the different skew slots, the different pole arc coefficients and the different widths of slot mouth are obtained, which can effectively reduce the cogging torque of in-wheel motor, but they still exists some limitations. The final simulation analysis results are in good agreement with the theoretical predicting results, which indicates that this method can be used to afford a theoretical basis to reduce the cogging torque and optimize the in-wheel motor of electric vehicle in the future.     

低速大力矩圆筒永磁直线电机齿槽力分析

为削弱圆筒永磁直线电机的齿槽力,采用了一种基于能量法和傅里叶分解的解析分析方法,推导出了圆筒直线电机与结构参数有关的齿槽力表达式。在此基础上,研究了定子极距所作的微小改变和极弧系数的优化选择对齿槽力的影响,提出了减少电机齿槽力的优化方案,并利用有限元法对其进行了验证。通过抽油机实际测试,其测试结果证明所提出的方法是正确有效的。     

考虑定位力及波纹力的电磁悬架作动器波动力抑制方法

针对轮边驱动电动汽车设计了一种直驱式的电磁悬架作动器。针对作动器存在的电磁力波动大的问题,提出了从空载定位力及负载波纹力两方面进行抑制的方法。建立作动器的磁场理论计算模型,通过对绕组磁链及感应电动势进行解析,验证了有限元模型的正确性。空载情况下基于有限元模型参数化分析了端部齿长度对定位力的影响,改进了定子长度。以感应电动势总谐波畸变率THD值作为评价指标,考虑了负载情况下的波纹力,通过改进槽口的宽度,以减小THD值及电磁力的波动。结果表明：当定子长度为182 mm时,定位力最小为24.0N,减小了75.6N;当槽口宽度为4.5 mm时,感应电动势THD值最小为4.5%,波纹力减小了3.2N。改进后作动器电磁力波动值仅为20.8N,降幅为80.1%,有效解决了波动力大的问题。     

双转子平动式啮合电动机设计与转矩分析

提出一种新型的四相双转子平动式啮合电动机,该电动机的每个磁极由一个定子和内、外转子构成.4个磁极的内转子固连在一起构成一个4极内平动转子,外转子固连在一起构成一个4极外平动转子.控制磁极的工作顺序,可以驱动内、外平动转子在4个偏心轴约束下作方向相反且同步的公转运动,并带动两个内齿圈与外齿轮啮合输出低速大扭矩运动,该结构相互抵消了惯性力,增大了输出转矩.设计制作物理样机,运用有限元法分析在不同转子位置角的磁链特性.依据磁共能原理,计算电动机的静态转矩.通过样机试验获得电动机的转速、转矩特性.与传统的电动机和减速器组成的驱动装置相比较,双转子平动式啮合电动机具有起动快、效率高、输出转矩大的特点,是一种可行的平动电动机结构.     

Optimal design to reduce torque ripple of IPM motor with radial based function meta-model considering design sensitivity analysis

In this study, optimum design process to reduce a torque ripple was presented for an interior permanent magnet (IPM) type electric traction motor. Firstly, 2-D electromagnetic finite element analysis was conducted to analyze the characteristics of the torque ripple in a view of magnetic saturation as well as cogging torque. Then, design factors of stator shape and rotor shape affecting to the torque ripple was selected as design variables. Secondly, using selected design variables, sensitivity analysis was performed to select design variable more affecting to the torque ripple and output torque by using design of experiments method. Thirdly, radial based function meta-model was constructed based on the results of the design of experiments (DOE). Finally, the optimum design was performed by using the constructed meta-model and method of feasible direction. By using the presented optimum design process, it is confirmed that the torque ripple of the optimum design was reduced to compare with the initial design and that output torque performance of the optimum design was maintained.

     

A study on dynamic performance of closed-loop commuted stepping motor to improve precision motion control

To achieve precision movements, a motor with very low speed ripple and torque ripple is required. A motor with more poles will normally give higher ripple frequency and hence lower ripple magnitude. The hybrid stepping motor when commuted in closed-loop mode will behave in the form of a multi-pole brushless DC servo motor with each step similar to one pole. To reduce torque ripple further, the commutation of the coils requires careful adjustment of the lead angle in order to compensate for the time constant of the coils at different speeds. This article establishes an accurate dynamic model for the closed-loop commuted hybrid-type stepping motor, which takes into account the drive circuit and the effect of magnetic saturation. Simulations have been performed on the model using the stiff system numerical method for higher accuracy. The results show a good match between the numerical solution and the actual measurement. The dynamic model developed can be used to predict speed ripple of the motor system under various commutation methods. This provides a means of minimizing speed ripple by using software to improve the accuracy of motion control systems on high-precision machines.     

基于DRNN动态整定PMSM的SVPWM控制

为解决传统的永磁同步电机控制系统中存在的低速转矩脉动大以及由此引起的高频噪声、动态响应慢等问题,提出了一种基于对角神经网络动态自整定的永磁同步电机矢量控制系统的实施方案.给出了基于对角递归神经网络的PID动态自整定控制器的结构,以及PID参数动态自整定的学习控制算法,并将这种综合控制策略引入永磁同步电机空间电压矢量PWM控制中.仿真结果表明,系统低速性能好,转矩脉动小,谐波含量少,当电机参数改变或者受到外部扰动时,系统具有良好的动态特性.     

Modeling of a linear motor feed drive including pre-rolling friction and aperiodic cogging and ripple

This work addresses the systematic modeling of a linear feed drive based on a linear synchronous motor, a helpful step in control design for precise machine tools using linear motors. The model considers the electrical dynamics, ripple, cogging effects, and friction. For ripple and cogging, periodic and aperiodic behaviors are analyzed, and simple models are proposed to reflect the observed behavior. Friction is represented by the generalized Maxwell-slip model Al-Bender (IEEE Trans Autom Control 50:1883–1887, 2005), and the particular manner in which pre-rolling parameters and Stribeck curve were determined for the current system is shown here for completeness. Finally, the model shows a good performance both in simulation and feedforward control.     

Torque ripple reduction of brushless DC motor based on adaptive input-output feedback linearization

Torque ripple reduction of Brushless DC Motors (BLDCs) is an interesting subject in variable speed AC drives. In this paper at first, a mathematical expression for torque ripple harmonics is obtained. Then for a non-ideal BLDC motor with known harmonic contents of back-EMF, calculation of desired reference current amplitudes, which are required to eliminate some selected harmonics of torque ripple, are reviewed. In order to inject the reference harmonic currents to the motor windings, an Adaptive Input-Output Feedback Linearization (AIOFBL) control is proposed, which generates the reference voltages for three phases voltage source inverter in stationary reference frame. Experimental results are presented to show the capability and validity of the proposed control method and are compared with the vector control in Multi-Reference Frame (MRF) and Pseudo-Vector Control (P-VC) method results.     

开关磁阻电机结构性转矩脉动抑制方法

开关磁阻电机具有结构简单、成本低和调速范围广等优势,但其双凸极结构和控制器的开关特性,导致存在转矩脉动现象,使得抑制转矩脉动成为焦点问题。首先从开关磁阻电机的结构和运行机理出发,针对线性解析方法难以分析转矩特征的问题,建立电机有限元模型求解出转矩特征并进行样机验证试验。分析样机结构参数对转矩脉动的影响,针对结构参数耦合问题,选择NSGA-Ⅱ算法在参数优化平台上对样机结构参数进行多目标寻优,在保证优化后样机的转矩脉动系数和平均转矩均优于初始电机的条件下,最终获得样机最优化结果。结果表明,不同结构参数对电机转矩的影响有较大的差异,对结构参数的优化能有效地抑制转矩脉动,该参数优化方法可以为开关磁阻电机结构性转矩脉动抑制提供参考。