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1.
崔巍  江建中  汪信尧 《电源学报》2003,1(3):486-490
本文提出了一种高功率密度的具有各相磁路独立特点的正弦波永磁电机。通过电机各相磁路的解耦,在很大程度上简化了电机的数学模型,降低了PMSM的强耦合性。此外通过对电机内反电势的优化设计,有效地降低了反电势的谐波分量,使得由于反电势的畸变造成的纹波转矩大大减少。  相似文献   

2.
永磁同步电机转子磁极的极性判别方法   总被引:1,自引:0,他引:1  
针对永磁同步电机转子磁极的极性判别问题,依据电枢绕组的磁饱和特性,从电机的高频数学模型入手,提出一种以PWM逆变器载波频率成份作为高频信号源的极性判别方法。为了能够产生旋转的载波频率成份信号,逆变器采用三相三角波载波SPWM调制方式,并给出了该调制模式下的载波频率成份电压表达式。推导了α-β坐标系下的载波频率成份电流矢量方程,方程中的饱和分量幅值包含转子磁极的极性信息。利用外差处理电路提取饱和分量,进而实现了对永磁同步电机转子磁极的极性辨别。仿真和实验结果证明了理论分析的正确性。该方法不需要知道电机的精确参数,也不需要向电机注入额外的特定高频信号,能够判别PMSM转子磁极的极性。  相似文献   

3.
在分析永磁同步电机矢量控制基本原理的基础上,提出一种新型智能矢量控制器。其中,神经元用于速度控制,神经网络用于空间矢量脉宽调制。神经元速度控制器结构简单,计算量小,具有快速的动态响应和较高的稳态精度;而基于神经网络的空间矢量脉宽调制(ANN-SVM)算法实现容易,同时可以降低电流谐波。在Matlab/Simulink环境下建立永磁同步电机新型智能矢量控制系统仿真模型并进行仿真研究,仿真结果验证了新型智能矢量控制器的可行性和有效性。  相似文献   

4.
李欣  龚高 《家电科技》2021,(4):98-101
磁悬浮轴承常应用于高速工况,传统滚珠轴承的极限转速较低,成为制约其作为辅助轴承可靠性的关键因素,而采用双层轴承将有效提高轴承的极限转速.以单层混合陶瓷球轴承为对象,分析磁悬浮轴承失电后高速转子跌落至辅助轴承后的动力学过程,得到轴承转速变化规律;进而研究双层轴承相较于单层轴承的转速分配情况,分析其转速提升情况.通过对双层...  相似文献   

5.
针对传统的直接转矩控制转矩脉动大、开关频率不恒定等问题,在分析永磁同步电机数学模型的基础上,综合矢量控制的特点,提出一种基于空间矢量脉宽调制的新型直接转矩控制系统,用PI调节器取代滞环控制器,用空间矢量脉宽调制取代开关表.同时为了提高系统性能,模糊控制被应用于该系统.在Matlab环境下建立永磁同步电机新型直接转矩控制系统仿真模型并进行仿真研究,仿真结果证明了新型直接转矩控制系统设计可行有效,在提高系统响应速度的同时,能有效减小转矩和磁链的脉动,改善控制系统的性能.  相似文献   

6.
A new compact MAX representation for 2‐D continuous piecewise‐linear (PWL) functions is developed in this paper. The representation is promising since it can be easily generalized into higher dimensions. We also establish the explicit functional form of basis function and demonstrate that the proposed basis function is the elementary ‘building block’ from which a fully general 2‐D PWL function can be constructed. In addition, we reveal the relationship of basis function with minimal degenerate intersection and Hinging Hyperplane, which shows that the MAX model can unify Chua's canonical expression, Li's representation, lattice PWL function and Bremann's Hinging Finding Algorithm into one common theoretical framework. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

7.
OBJECT: A selective-excitation radiofrequency (RF) pulse that uses hard pulses composed of a sequence of composite pulses with positive and negative phases (P/N pulse) is proposed herein. Because the amplitude of the RF signal is unchanged during the excitation, RF amplification can be accomplished using a nonlinear RF power amplifier (i.e., class C or D type). MATERIALS AND METHODS: In this article, Fourier series have been first used to analyze the equivalence between the proposed P/N pulse and the conventional soft pulse on selective excitation. Subsequently, computer simulations based on density-matrix theory are used to compare the excitation profiles of both the soft and the P/N pulses. RESULTS: The excitation profiles of the P/N pulses have been measured experimentally through a home-built 0.3-T magnetic resonance imaging (MRI) system. In addition, several slices of images have been obtained as proofs by using the multislice two-dimensional spin echo sequence through replacement of the conventional soft pulse by the proposed P/N pulse. CONCLUSION: Because the perfect selectivity of the proposed P/N pulse, it can be used for imaging studies to improve the efficiency of amplification at the lowest cost.  相似文献   

8.
永磁同步电动机起动时如果知道转子的初始位置,起动将会十分简便。但是,永磁同步电动机的转子初始位置确定或估计一直是个难题。针对现有常用方法的一些不足,结合通用的增量编码器,在DSP的硬件平台上,实现了永磁同步电机的初始角定位。电机精确定位前只需要转60°,并且不需要微振。实验证明。该方法初始角辨识准确,实用性强。  相似文献   

9.
永磁同步电机神经网络逆解耦控制研究   总被引:1,自引:0,他引:1  
针对永磁同步电机的非线性、多变量、强耦合的特点,将神经网络与逆系统解耦方法相结合,并用于永磁同步电机的解耦控制.分析永磁同步电机的数学模型与解析逆模型,完成系统可逆性证明,将永磁同步电机与解析逆系统等效成两个伪线性子系统,构造神经网络逆系统,将永磁同步电机动态解耦为一阶线性磁链子系统与二阶线性转速子系统,利用两个PID控制器对伪线性子系统进行闭环控制器设计,实现系统转速与定子磁链动态解耦控制.利用dSPACE半物理仿真系统完成神经网络训练数据的采集与系统解耦控制实验.结果表明神经网络逆系统方法可以实现永磁同步电机的高新能控制,对负载扰动具有较强的鲁棒性.  相似文献   

10.
An unbalance on a rotor causes whirling motions of the rotor and alternating forces of the bearings in rotating machines. The authors have shown a magnetic bearing control system in which an unbalanced rotor can be suspended without whirling. The concept of designing the control system involved an observer estimating the effects of unbalance and then cancelling using the electromagnetic forces of the bearing. With the control method applied, the position of the rotor can be maintained at the desired position with high precision. However, it is suitable for some machines to minimize the variation of exciting currents or vibratory force transmitted to the base through the bearing. This paper presents control methods that can eliminate stationary alternating components from exciting currents or electromagnetic forces by using the output of the observer. Another control method is presented in which feedback of the estimated signals of the displacements of the principal axis occurs; such signals are obtained by compensating synchronous observatory disturbances by use of the output of the observer. It is shown that the proposed three control methods are equivalent when unbalance stiffness due to the bias magnetic flux is null.  相似文献   

11.
Abstract

In order to improve power density of high-power electric motorcycle driving motor, the air-gap length is usually minimized, which aggravates the influence of armature reaction on air-gap magnetic field. Considering the fact of unidirectional driving of electric motorcycle, the eccentric air-gap is used in each pole air-gap magnetic field strengthened area to suppress armature reaction, thus an asymmetric eccentric air-gap structure is designed. The torque and efficiency of motor are improved by asymmetric structure optimizing to improve the comfort, load capacity and battery life of vehicle, the ratio of maximum air-gap to minimum air-gap is eventually determined to be 3.2. The results of simulation and experiment show that, for the specified rotation direction, the distortion of air-gap magnetic density and back electromotive force (back-EMF) caused by armature reaction can be significantly suppressed by the determined asymmetric structure, hence the torque ripple and iron loss are reduced by 70.66% and 20.9% under rated load, respectively. Meanwhile, the proposed motor can provide a wide speed range and superior speed control performance, thus, verifying the validity and feasibility of the proposed asymmetric eccentric air-gap structure.  相似文献   

12.

Object  

Staff operating in the environment of magnetic resonance imaging (MRI) scanners are exposed daily to static magnetic fields (MFs). To protect workers several guidelines are present in literature reporting exposure limits values expressed in terms of magnetic flux density or induced current density. We present here a novel tool for estimating the induced current density due to worker movement in the MR environment.  相似文献   

13.
针对国内洗衣机电机驱动系统技术落后的现状,利用现有永磁同步电机(Permanent Magnet Synchronous Motor,简称PMSM)的位置预估算法,结合洗衣机用直接驱动PMSM系统的特点,开发了一种利用两相正交锁定型开关霍尔传感元件的低成本位置预估算法.理论分析和实验结果表明,该算法具有较高的稳态性能,很适合稳速控制.  相似文献   

14.
一种永磁同步电机无速度传感器的矢量控制   总被引:6,自引:0,他引:6  
研究了一种基于MRAS的永磁同步电机速度辨识方案:将永磁同步电机的电流模型作为参考模型,估算的定子磁链模型作为可调模型,设计了自适应律同时辨识电机转速和定子电阻.利用该方案建立了永磁同步电机的无速度传感器矢量控制系统.仿真和实验结果表明,该方案在高、低速以及转速突变时均能准确检测转子的速度以及在线辨识定子电阻,系统具有良好的静、动态调速性能.  相似文献   

15.
实心磁铁推力磁轴承最佳工作点求解方法   总被引:1,自引:0,他引:1  
力和温升是影响实心磁铁推力磁轴承工作性能的主要因素。本文建立了实心磁铁推力磁轴承承载力-温升分析模型。通过一个应用实例的计算,对系统承载力、温升及力-温升特性进行了分析。结果表明:实心磁铁推力磁轴承存在最佳工作点,影响轴承承载力-温升特性的主要因素是静态气隙和绕组安匝数,且对静态气隙更敏感。选定了适当的静态气隙后,可以通过调整安匝数使轴承运行在最佳工作点附近,从而实现了轴承性能优化。  相似文献   

16.
本文简要叙述了永磁同步电动机(PMSM)的矢量控制理论,并在此基础上给出了其矢量控制调速系统的构成框图.为实现全数字化控制并使系统具有良好的性能,采用专用于电机控制的TMS320F240-DSP芯片为核心实现其对PMSM的控制.本文给出了详细的软硬件实现方案,整个系统控制方法可通过编写软件实现.  相似文献   

17.
针对永磁同步电机存在失磁问题,提出了一种基于级联自适应滑模观测器的失磁故障实时检测方法。首先,针对定子电阻发生时变变化而导致传统自适应观测器无法准确检测失磁故障问题,提出将改进型自适应与滑模变结构控制相结合的方法,设计了级联自适应滑模观测器,并给出了定子电阻的自适应估计算法。然后利用滑模变结构等值控制原理,建立估计永磁体磁链算式。最后,通过仿真以及实验验证,证明了所提方法的可行性和有效性。  相似文献   

18.
介绍了微机无刷同步电动机励磁系统的组成及原理,详细分析了该系统的高技术性能和智能化的操作与维护。  相似文献   

19.
针对混合径向磁轴承用的位移传感器容易发生故障可靠性不高的问题,依据冗余位移传感器检测思路,采用坐标变换矩阵技术,提出一种位移传感器的故障识别与容错控制方法.通过将位移传感器非对称安装在混合径向磁轴承的外围,根据位移传感器的故障状态选取不同的坐标变换矩阵,实现转子在水平和竖直两个自由度上的位移检测.传感器位置的非对称安装...  相似文献   

20.
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