基于磁链预测的永磁直驱风力发电机SVM-DTC技术

永磁直驱风力发电机传统直接转矩控制（DTC）通过查表法选择固定电压矢量来控制定子磁链和电磁转矩,导致磁链和转矩的双重控制要求不能同时兼顾,造成磁链和转矩脉动过大。针对传统DTC的不足,研究了一种永磁直驱风力发电机基于定子磁链预测的空间矢量脉宽调制（SVPWM）DTC方法,通过对下一个控制周期磁链矢量的预测计算需要补偿的电压矢量,并引入SVPWM模块代替查表法来合成该电压矢量。仿真和实验结果表明,此方案能明显降低磁链和转矩脉动,改善永磁直驱风力发电系统的控制性能。     

基于ADRC和SVM的永磁同步电机直接转矩控制

针对永磁同步电机(PMSM)传统直接转矩(DTC)控制系统的抗干扰性差、磁链脉动大和开关频率不稳定的问题,提出了一种基于自抗扰控制器(ADRC)和空间电压矢量调制(SVM)结合的新型控制方法;ADRC可以实时地估计系统的扰动并进行补偿,提高了系统的抗干扰性能;SVM稳定了周期开关频率,有效地降低了磁链脉动。仿真结果证明,与传统DTC相比,文中提出的新型控制方法能够准确地估计出系统所受的扰动并及时补偿,稳定性高,反应速度快,磁链脉动小。     

基于定子磁链矢量预测的DTC系统研究

针对直接转矩控制(DTC)技术中采用的传统滞环控制存在转矩及电流脉动大,过电压扇区时磁链轨迹畸变的缺点,提出一种基于定子磁链矢量预测的直接转矩控制方法。首先,根据磁链和转矩的偏差,预测出下一个控制周期的磁链矢量;然后,用预测磁链矢量减去当前的磁链矢量,得到需要加在电机定子上的电压矢量,以补偿当前的偏差。通过仿真说明了改进的系统抑制了磁链和转矩脉动,改善了电流波形,抑制了谐波,具有较好的动静态性能。     

基于空间矢量调制的PMSM直接转矩控制研究

针对传统的直接转矩控制（DTC）出现的开关频率不恒定,磁链和转矩脉动大的问题,提出一种基于空间矢量调制的直接转矩控制（SVM-DTC）方法。该方法集合了直接转矩控制响应快、矢量控制连续平滑的优点,以永磁同步电机（PMSM）数学模型为基础,建立转矩、磁链双闭环PI控制回路。采用空间电压矢量调制策略,将转矩和磁链作为控制量。仿真结果表明,相对于传统的直接转矩控制,基于空间矢量调制的直接转矩控制方案的开关频率恒定,转矩、磁链脉动小,系统具有良好的动、静态性能,验证了该方法的可行性和有效性。     

基于BP网络的开关磁阻电机变磁链DTC方法研究

文章针对传统定磁链双闭环DTC调速系统稳态时定子电流幅值较大、电机铜耗增加的问题,提出了变磁链给定的解决方案,建立了变磁链三闭环DTC调速系统。仿真结果证明,此调速系统动、静态性能良好,既能充分抑制SRM的转矩脉动,又能在稳态时降低定子电流的幅值,解决了电机高速时铜耗较大的问题。另外,针对变磁链三闭环DTC调速系统控制参数复杂,实时性要求高的特点,文章将BP神经网络PID控制器与传统PI控制器复合,构成了BP-PI控制器。仿真表明,BP-PI控制器有效克服了单一神经网络DTC控制器存在的缺陷,动、静态性能明显优于传统PI调节器,显著提高了调速系统的自适应性和鲁棒性。     

基于滑模控制的永磁同步电机直接转矩控制研究

针对永磁同步电机直接转矩控制(DTC)存在较大的电磁转矩脉动、磁链脉动、低速性能不理想等问题,文中引入滑模控制策略对永磁同步电机进行直接转矩控制。通过建立PMSM的矢量数学模型,设计基于滑模控制的直接转矩控制器,利用MATLAB/Simulink进行建模仿真分析。结果表明,与传统DTC相比,基于滑模控制策略的永磁同步电机直接转矩控制系统中电磁转矩脉动幅值更低,且具有更好的动态性能和抗扰动能力,可以更加有效地改善系统特性,满足实际电机控制的需要。     

基于SVPWM的永磁同步电机直接转矩控制系统的研究

将空间矢量脉宽调制技术(SVPWM)引入到了永磁同步电机的直接转矩控制(DTC)当中,实现了电压空间矢量的连续调节。定子磁链近似为圆形,有效地解决了常规DTC系统电磁转矩脉动较大的问题。在MATLAB/Simulink环境下搭建了永磁同步电机基于SVPWM的直接转矩控制系统的模型,对电机的多种运行状态进行了仿真,验证了控制理论的正确性和有效性。     

基于全维状态观测器的永磁同步电机无差拍直接转矩控制

永磁同步电机传统的直接转矩控制存在磁链幅值和转矩脉动大的缺点。文中研究了基于状态观测器的无差拍直接转矩控制方案,通过构造全维状态观测器的方法来观测定子磁链幅值,消除了初始磁链误差以及电机参数对传统的观测方法影响的问题。此外针对传统控制系统产生的时滞现象,文中的研究提前一个周期计算出所需的电压矢量,实现了转矩和磁链无差拍控制。仿真结果表明,所提出的基于全维状态观测器的无差拍控制能较好地抑制磁链和转矩脉动,具有良好的控制性能。     

基于DTC感应异步电机的Matlab仿真研究

本文介绍了直接转矩控制系统和控制原理，并对系统建立状态空间数学模型。采用了磁链和转矩的优化设计思想，借助于Matlab给出了DTC的仿真波形。仿真和实验表明：DTC控制具有更好的稳定性，较强的鲁棒性和抑制扰动的能力。     

基于ESO磁链观测器的直接转矩控制的研究

讨论直接转矩控制方法在永磁同步电机中的应用问题,利用MATLAB仿真工具对永磁同步电机直接转矩控制系统仿真。针对直接转矩控制低速时存在较大转矩脉动的问题,采用观测器方法克服传统磁链模型中参数的不确定性对磁链观测精度的影响,保证全速范围内磁链的准确估计,提高控制性能。仿真表明观测磁链具有较高的精度,对电阻的不确定变化具有较强的鲁棒性,并可准确估计无速度传感器的速度及位置。     

基于推力磁链的永磁直线同步电机自适应观测器

永磁直线同步电机由于结构的特殊性使其直交轴电感不相等,数学模型变得较为复杂,传统的观测器不再适用于直线电机。同时直接推力控制依赖观测器观测结果的准确性,尤其在低速阶段,以线性模型为基础建立的观测器不能很好地适应电机参数变化。根据永磁直线同步电机的数学模型,采用了推力磁链等效的方法,简化了其数学模型,从而解决了交直轴电感不相等引起的推力观测误差。同时,在自适应观测器中引入定子电阻自适应律,减小了低速段由于电机参数变化引起的定子磁链观测误差,提高了直接推力控制的低速段性能。并建立了相关的仿真模型,对定子磁链和电磁推力的观测效果进行了分析,从而验证了基于推力磁链的自适应观测器的有效性。     

基于THS320F2812的开关磁阻电机磁链特性检测

本文研究了开关磁阻电机（SRM）磁链特性实验检测方法,建立了基于DSP芯片TMS320F2812的SRM磁链检测系统,利用ADC模块实时采集不同转子位置的电压、电流信号,将数据传送到上位机,根据间接磁链测量原理,由数字离散方法计算磁链值,得到SRM磁链电流特性曲线和磁链-转子位置-电流模型。     

Estimation of the flux linkage in a direct-torque-controlled drive

An improved integration method is presented for the estimation of the stator flux linkage for speed- and position-sensorless direct-torque-controlled AC machine drives. The method is based on monitoring the scalar product of the estimated stator flux linkage and the measured stator current. The AC part of the scalar product is extracted using filtering and the correction for the estimated stator flux linkage is formed from that part. Adequate performance is obtained by using simple low-pass filtering. By using adaptive filtering in the extraction, the performance of the drive is excellent. Both simulation and laboratory test results are presented, which show that the presented method works well both in steady state and in transients.     

水轮机转子磁悬浮承重系统之电磁装置漏磁研究

面对传统推力轴承支承系统存在的问题,本着采用混合磁悬浮装置和传统推力轴承共同完成支撑的目的,研究了漏磁对电磁装置的影响。为此,引入了气隙比的概念,提出了通过改变气隙比的值来研究漏磁对系统悬浮力的影响,通过一系列仿真,得出了随着漏磁的增加,系统电磁悬浮力反而增大的结论。结合了陕西安康水电站水轮机组的数据,通过各方面的约束,在永磁装置确定的情况下,计算出了电磁装置较优的电气及结构参数。     

基于SVPWM的永磁同步电动机直接转矩控制

针对永磁同步电动机直接转矩控制系统转矩和定子磁链脉动问题,采用电压空间矢量脉宽调制(SVPWM)的永磁同步电动机直接转矩控制方法。根据在每一个控制周期内,计算出参考磁链和所估计磁链的偏差,选择相邻非零矢量和零矢量,并精确地计算出各自的作用时间,然后利用线性组合法将其合成为新的电压矢量。仿真结果表明,所提出的控制方案是有效的,明显地改善转矩和磁链脉动,并且有很好的动态和稳态性能。     

Variable reluctance motor characterization

A technique to develop a simple, nonlinear dynamic model (from measurements of flux linkage) which captures all of the relevant dynamics of the motor over its entire operating regime is described. A least squares data reduction algorithm that handles the analyses in a natural way to generate bivariate polynomials to approximate the flux linkage is given. Comparisons with a theoretical method and other measurements are presented     

Comparison of the dynamic response of radial and tangentialmagnetic flux thrust bearings

Theoretical predictions were made for the dynamic performance of a tangential flux magnetic thrust bearing. A prototype bearing was built with the stators and rotors made from tape wound strip. The performance of this bearing was measured and compared to the theoretical predictions and also to the performance of a radial flux thrust bearing. Tangential flux bearings are intrinsically amenable to construction from tape wound cores. Tape wound cores come in high saturation alloys like supermenduer which can give the bearing a high force to size ratio. The thin tape laminates give the bearing a broad frequency bandwidth. By comparison the paper shows that it is difficult to make a laminated rotor magnetically efficient for radial flux bearings. A test rig is described that was built to measure the performance of the tangential flux bearing. A power amplifier with current feedback provides DC and harmonic currents to the coils. A load cell was built into the test rig to measure the axial thrust, an inductive/Hall sensor was included to measure the coil current, and a Hall probe was used to measure the gap flux     

A novel direct torque controlled interior permanent magnet synchronous machine drive with low ripple in flux and torque and fixed switching frequency

A modified direct torque control (DTC) scheme for interior permanent magnet synchronous machine (IPMSM) is investigated in this paper, which features in very low flux and torque ripple and almost fixed switching frequency. It is based on the compensation of the error flux linkage vector by means of space vector modulation. Modeling and experimental results show that the flux and torque ripples are greatly reduced when compared with those of the basic DTC. With the new scheme, very short sampling time is not essential. All the advantages of the basic DTC are still retained. In addition, fixed switching frequency at different operating conditions becomes possible. The field-weakening control of this drive is also studied; an IPM DTC drive with a wider operation range and lower flux and torque ripple has been achieved experimentally.     

Robust control using neural network uncertainty observer for linearinduction motor servo drive

A robust controller, that combines the merits of integral-proportional (IP) position control and neural network (NN) observed technique, is designed for a linear induction motor (LIM) servo drive in this study. First, the secondary flux of the LIM is estimated using a sliding-mode flux observer on the stationary reference frame and the feedback linearization theory is used to decouple the thrust and the flux amplitude of the LIM. Then, the IP position controller is designed according to the estimated mover parameters to match the time-domain command tracking specifications. Moreover, a robust controller is formulated using the NN uncertainty observer, which is implemented to estimate the lumped uncertainty of the controlled plant, as an inner-loop force controller to increase the robustness of the LIM servo drive system. Furthermore, in the derivation of the online training algorithm of the NN, an error function is used in the Lyapunov function to avoid the real-time identification of the system Jacobian. In addition, to increase the speed and accuracy of the estimated flux, the sliding-mode flux observer is implemented using a 32 bit floating-point digital signal processor (DSP) with a high sampling rate. The effectiveness of the proposed control scheme is verified by both the simulated and experimental results