E型铁心开关磁通电机的电磁性能解析计算

由于复杂磁路的影响,开关磁通电机电磁性能的解析计算是个难点。采用子域法,通过子域划分、建立偏微分方程与通解、确立边界条件和积分常数求解等步骤建立E型铁心结构开关磁通电机的解析模型,计算得到了各子域矢量磁位、磁通密度、绕组磁链、电动势和电磁转矩,分析了不同定转子极数组合对绕组电动势和齿槽转矩的影响,得到了合适的极数组合。与有限元法计算结果的对比表明,空载时两者计算结果非常接近,负载时由于电枢反应磁场的影响,与非线性有限元相比,解析法会带来一定误差。虽然该解析模型不能考虑饱和的影响,由于解析法计算速度快,能得到规律性的结论,非常适合电机的初始设计和优化计算。     

一种无速度传感器感应电机鲁棒滑模控制策略

设计了一种在同步旋转坐标系下的无速度传感器感应电机滑模速度和磁通控制方案,并设计了一种收敛速率可调的闭环滑模磁通观测器。Lyapunov稳定性理论推导和仿真结果均证明了该控制策略和磁通观测器对参数摄动和不确定因素有很强的鲁棒性。为了削弱变结构控制中的抖振现象,采用饱和函数来代替符号函数。在转速观测器中加入在线估计负载转矩环节,使得转速观测器对负载转矩变化具有良好的鲁棒性。在电机参数和负载发生剧烈变化的情况下,分别利用该控制策略和精确反馈线性化控制方法进行了对比仿真。仿真结果验证了该控制策略与观测器的有效性。     

考虑磁饱和特性下特殊位置电感的开关磁阻电机无位置传感器控制

开关磁阻电机（SRM）在实际运行时由于负载增加导致电流增大,会使SRM进入磁饱和工作状态。传统的无位置传感器控制方法解决磁饱和问题需要进行大量离线测量。因此,提出一种基于特殊位置判断的SRM无位置传感器控制策略。该方法通过向非导通相注入高频脉冲电压以得到全周期电感,通过电感曲线非饱和段的线性变化关系在线得出15°、30°、45°、60° 4个特殊位置对应的非饱和相电感值,根据电感与角度对应关系,在一个周期内得到4个特殊位置,通过相邻2次位置估算电机转速与全周期转子位置。在此基础上,搭建了基于Simulink的仿真模型和基于DSP的试验平台,通过仿真与试验验证了该方法的正确性。     

新型定子双馈双凸极永磁电机研究

研究了一种新型定子双馈双凸极永磁电机，该电机采用定子双馈形式，也就是定子上既有电枢绕组，又有励磁绕组，特别是在永磁体旁边附加了一条并联磁分路，通过磁分路磁阻的适当设计，可以达到用较小的直流励磁磁势获得较大气隙磁通调节范围的目的。本文介绍了样机的结构特点，分析了气隙磁通调节范围、直流励磁磁势和并联磁分路磁阻三者之间的关系，进行了样机磁场的有限元计算，样机试验与设计吻合。该电机结构新颖，励磁控制简单，调磁效果明显，励磁损耗小，具有较高的研究和实用价值。     

具有变磁阻励磁回路的永磁同步电动机电感参数

为解决永磁同步电动机弱磁问题,提出了一种能够跟随转速自动调节励磁磁阻的新型永磁同步电动机.在介绍电机基本结构和原理的基础上,通过不同励磁下电机磁力线分布,指出了影响交直轴电感主要有永磁体、隔磁磁桥和交直轴电流.并分别就永磁体厚度、隔磁桥尺寸、电流饱和、非导磁体的引入和永磁体的运动,运用有限元数值法计算了交直轴电感.计算结果与电感分析结果和测试结果相吻合.     

Sensorless Control of Synchronous Reluctance Motors Based on Extended EMF Models Considering Magnetic Saturation With Online Parameter Identification

A sensorless control method based on novel extended electromotive force (EEMF) models considering magnetic saturation is proposed for synchronous reluctance motors (SynRMs). Since motor parameters, particularly inductances, vary largely in SynRMs, a precise sensorless control is necessary for fully considering such variations. In this paper, the EEMF model, taking into consideration magnetic saturation, is derived and is applied to a position estimation method. The two EEMF models caused by a difference in the$d$-axis direction are shown, and the appropriate EEMF model that can suppress a position estimation error caused by the deviation of inductance parameters is proposed. Moreover, an online parameter identification method for sensorless control in middle- or high-speed ranges is proposed. The necessity for the use of the model, taking into consideration magnetic saturation, is verified by experiments. The proposed sensorless control system is shown useful by experiments.     

霍尔电流互感器的仿真设计

利用ANSYS分析软件建立三维模型,应用三维有限元非线性磁场分析计算出霍尔电流互感器开口气隙处的磁通密度。在此基础上,计算了铁心的饱和点并研究了气隙宽度对磁通密度的影响。实验表明计算方法和结果是正确的。     

Position-sensorless starting method and driving characteristics of closed-slot small permanent-magnet motor

This paper describes a method of estimating the rotor position of a surface permanent-magnet motor with a closed-slot stator for sensorless starting by using the effect of partial magnetic saturation. It also describes a starting scheme for the motor. Since the closed-slot stator is partially saturated at 12% of the rated stator current, this method reduces noise and vibration. Experimental results on the driving characteristics of the motor are also presented.     

一种复合转子永磁无刷直流电机恒率弱磁的研究方法

由永磁段和磁阻段构成的复合转子是永磁同步电机实现弱磁的有效结构，也可用于永磁无刷直流电机(BLDCM)中。为求解复合转子结构BLDCM的复杂磁场，分析转子加入磁阻段对弱磁性能的影响，需要引入一种有效的弱磁控制模型。该文通过建立场路结合的状态空间模型将磁场与通电模式相结合，准确模拟了最小分析区间中转子每个位置磁状态；以磁链空间位置函数的差分替代磁链对位置的偏微分，采用准静态场有限元分析解决BLDCM运行中磁场随空间位置变化的复杂性以及高速时无功电流增加带来磁路饱和的非线性，为准确预测复合转子BLDCM的弱磁性能提供了有效的处理手法。样机试验与仿真结果的吻合表明了这种方法的准确性。     

基于改进的开关磁阻电机无位置传感器技术

由于开关磁阻电机(SRM)的双凸极结构与高饱和性,其磁链为相电流和转子位置的高度非线性函数.在简化磁链法中建立精确而小规模的SRM磁链模型,是实现SRM无位置传感器控制的关键.采用预处理方法优化神经网络(BPNN)模型可以减小尺度,提高精度;为了进一步优化该模型,在此基础上提出粒子群(PSO)优化BPNN的建模方法.利...     

Compensation of Parameter Variation Effects in Sensorless Indirect Vector Controlled Induction Machines Using Model-Based Approach

The majority of speed estimation schemes for sensorless vector control of induction machines use a mathematical model of the machine in the estimation process. These schemes are therefore inherently sensitive to parameter variation effects in the machine. The variety of speed estimation methods makes any attempt to develop a universal approach to compensation of parameter variation effects impossible. This paper concentrates on one of the most frequently used schemes, in which speed is estimated using model reference adaptive control approach (MRAC) on the basis of two estimated values of the rotor flux space vector. The estimator is analyzed in conjunction with indirect feed-forward rotor flux-oriented induction machine. An attempt is made to improve the accuracy of the speed estimation by appropriate modification of the speed estimator and the indirect vector controller structures using modified induction motor models that account for one or more of the phenomena that are neglected in development of the basic constant parameter scheme. In particular, compensation of main flux saturation, compensation of iron loss, and simultaneous compensation of both the iron loss and main flux saturation are elaborated. Novel structures of the speed estimator are developed for each of the three cases and are applied in conjunction with the appropriate modified form of the indirect rotor flux-oriented controller. Excellent compensation capability is demonstrated in all the cases by performing extensive simulation studies.     

基于多项式磁饱和模型及EKF的感应电机磁链观测

感应电机的转子磁链通常用定子电流进行观测,易受测量噪声影响,且观测模型精度与电机参数有关。当电机内磁场幅值变化时,磁路非线性饱和效应会引起互感参数波动,导致观测磁链的幅值和方向偏离实际值,使控制出现偏差。对此,提出基于四阶多项式磁饱和模型以及扩展卡尔曼滤波(EKF)的全状态估计算法,以定子电流作为反馈,观测转子磁链的同时,辨识互感参数。仿真及实验结果表明所提算法能降低磁饱和非线性对控制系统的影响。     

基于有无位置传感器的无刷直流电机双模控制器设计

提出了一种基于有无位置传感器的无刷直流电机(BLDCM)双模控制器.控制器在正常状态下以有位置传感器模式运行,一旦出现位置传感器损坏或者位置传感器信号传输故障等非正常情况,控制器将自动转换到无位置传感器模式运行.重点讨论了模式转换技术与无位置传感器运行模式下的转子位置检测技术.在电机静止和低速运行时,利用定子铁心线圈电感的磁饱和效应,采用短时脉冲检测以及最大概率法获得当前转子位置;在电机高速运行时,采用反电动势过零点检测方法实现转子定位.     

变压器电流差动保护改进方法

针对一种适用于Y,d或D,y接线变压器的电流差动保护改进方法进行了研究,该方法采用修正的差动电流来补偿励磁电流和剩磁的影响,制动电流与传统比率式差动保护相同。变压器铁心饱和前,采用一、二次侧相电流差作为差动电流;饱和后,则计算磁化电流来修正差动电流。该保护不受谐波和剩磁影响,不需要附加制动或闭锁技术。通过EMTP仿真将该保护与传统谐波制动原理的差动保护进行了比较,结果表明,励磁涌流和过励磁时,该保护能够保证不误动;内部故障时则不会像传统谐波制动原理的差动保护受制动信号影响而延迟动作。动模实验进一步验证了该保护的可行性和优越性。     

基于磁通轨迹特征的变压器励磁涌流识别新方法

介绍了变压器保护正常动作率的现状,分析了当前比较流行的变压器励磁涌流判断方法,并指出缺陷。提出了一种基于磁通轨迹特征的变压器励磁涌流识别新方法,该方法根据变压器发生内部故障时铁心不饱和,而出现励磁涌流时铁心饱和的原理,利用实测的变压器电压和电流量推算变压器主磁通的轨迹,通过提取主磁通轨迹的特征来判断主磁通变化范围,从而确定变压器是否发生励磁涌流。仿真结果证明了识别方法的可行性。     

基于高性能磁链算法的永磁同步电动机无位置传感器控制

准确的磁链辨识是基于磁链观测法永磁同步电动机无位置传感器控制的关键,传统电压型磁链辨识算法消除了纯积分存在漂移问题,对圆形磁场的磁链可以准确辨识,但对实际中电机内普遍存在的椭圆形磁场的磁链辨识时存在稳态幅值和相位误差。分析了椭圆形磁场时磁链矢量与反电动势矢量的空间关系。对传统算法辨识椭圆形磁链的误差进行了分析,提出一种改进的新型磁链算法。改进后的新算法运算量与传统算法相当,但对圆形与椭圆形磁场的磁链均能准确辨识。将新算法应用于一台表贴式永磁同步电动机无位置传感器控制系统的转子位置估算,仿真证明,在稳态及转速突变时新算法均具有良好的位置和转速跟踪效果。利用数字信号处理器TMS320F2812DSP对其进行了数字化实现。实验结果表明,在中高速范围内,调速系统在稳态与电机转速突变时具有良好的动静态特性,但在低速区会出现系统不稳定。仿真与实验证明了新算法的有效性和实际可应用性。     

Sensorless induction machine observation with nonlinear magnetic characteristic

This paper addresses the problem of state estimation in induction motors. Generally, the motor observer design has been dealt based on standard models neglecting the saturation effect in the magnetic characteristic. As a matter of fact, magnetic saturation cannot be ignored especially when considering control strategies (speed and torque) that involve large flux variations. Such large flux variations are necessary to meet optimal operation conditions in the presence of wide range load torque changes. On the other hand, it is well known that use of mechanical (speed and torque) sensors entails reliability issues. In this paper, a new sensorless adaptive observer is designed for induction machine based on a model that accounts for the nonlinear feature in the magnetic circuit. The observer consists of two interconnected state‐dependent gain observers and is formally shown to provide accurate estimates of the mechanical and magnetic variables using only stator current and voltage measurements. Copyright © 2013 John Wiley & Sons, Ltd.     

基于无速度传感器预测控制DTC系统研究

提出了一种基于空间矢量脉宽调制(SVPWM)预测控制方法的无速度传感器直接转矩控制(DTC)系统方案.根据转矩和定子磁链的误差,计算下一个控制周期输出的电压矢量,使该误差趋于零,并采用SVPWM调制方式合成该电压矢量,使开关频率恒定;选择合适的磁链检测方法,并基于模型参考自适应(MRAS)方法实现了无速度传感器的转速检测.在自主设计的变频器样机上实现了该系统方案,得到了较为理想的实验结果,并验证了系统设计方案的可行性.     

Stator-flux-based vector control of induction machines in magneticsaturation

In many variable-torque applications of induction machines, it is desirable to operate the machine at high flux levels, thus allowing the machine to produce higher torques. This can lead to saturation of the main flux path, introducing cross-coupling effects which can severely disrupt the performance of controllers dependent on knowledge of the machine's magnetic parameters. Stator flux-oriented torque-control schemes need not depend on the magnetic parameters of the machine and, hence, are potentially more robust and easier to implement in magnetic saturation than rotor-flux-oriented control. In this paper, the authors present and analyze a stator-flux-oriented torque-control scheme. This controller only requires knowledge of the stator voltage, stator current, and stator resistance. An analytical expression for the maximum achievable torque output of the machine using a linear magnetics model is compared with values calculated using a nonlinear magnetics model incorporating saturation of the main flux path and is shown to be a good approximation at high flux levels, when the main flux path is heavily saturated. Experiments carried out on a 3 hp 1800 RPM wound-rotor induction machine show smooth operation of the control scheme at torque levels up to at least four times rated torque     

共模扼流圈饱和效应分析及动态电感计算

研究了差模电流激励下的共模扼流圈磁饱和效应.建立了共模扼流圈的有限元分析模型.共模扼流圈三维磁场分布的仿真计算结果显示,磁芯中差模电流激励的磁通并没有完全抵消,仍有少量漏磁存在.这些漏磁增加了磁芯的磁通密度,并导致磁芯部分饱和.为得到共模扼流圈在磁芯部分饱和情况下的共模电感值,借助有限元数值分析,给出了求取共模扼流圈动态电感的计算方法.最后设计了测量差模电流激励下共模扼流圈动态饱和电感的实验,仿真计算与实验测量结果吻合较好,表明所提出的共模扼流圈动态电感的计算方法是有效的.