基于蚁群算法的同步发电机参数改进频域辨识方法

同步发电机参数频域辨识方法一般假设小扰动条件下励磁电压保持不变,但实际上,试验过程中励磁电压不断变化,扰动大小的划分也带有一定经验性。为此,提出了基于蚁群算法的同步发电机参数改进频域辨识方法,该方法需要实时测量扰动后的发电机功角、定子电压、电流以及励磁电压等变量,并应用快速傅里叶变换及功率谱算法将各电气量转换为频域信号。然后,在计及励磁电压变化的条件下,应用蚁群优化算法拟合发电机电压q轴分量的频域特性,从而辨识d轴最优参数。q轴运算电抗不受励磁电压影响,故可按照传统方法辨识q轴参数。对某电站水轮发电机的参数辨识验证了改进频域方法的有效性,与传统方法相比,改进频域辨识方法可适用于较大扰动的情况,且d轴参数辨识精度较高,收敛性更好,具有较好的实用性。     

同步发电机参数的一次性任意抛载测试方法

为简化同步发电机的抛载试验方法,在同步发电机功角可以测量的基础上,提出了一种用于同步发电机参数辨识的一次性任意抛载测试方法。对于同步发电机5阶模型,当同步发电机励磁电压不变,调速器不动作时,详细推导了任意抛载情况下的发电机端口电压包络线方程、励磁电流变化方程。论证结果表明,利用一次性任意抛载过程中的动态以及抛载前的稳态,以发电机励磁电流、定子电压、转速作为量测量,可以同时辨识全部d、q轴电气参数,而不需分d、q轴两次抛载试验,简化了试验过程。仿真计算验证了上述方法的有效性。     

利用励磁电压扰动后的同步发电机参数辨识

基于Matlab/Simulink建立同步发电机系统在励磁电压发生扰动时的电气模型,并通过Park变换,快速Fourier分解（FFT）得到同步发电机实用参数辨识所需d轴和q轴电压、电流的基频分量和励磁电压等电气数据。然后根据汽轮同步发电机六阶电气模型以及对应的电气微分方程进行辨识,微分方程的求解采用改进Euler法。在寻优辨识中先计算稳态参数,从而减少待求参数的维数,再利用改进的粒子群算法寻优辨识暂态参数。仿真算例的计算结果验证了该方法的正确性。     

基于多新息最小二乘法的同步发电机一次性抛载试验参数辨识

针对同步发电机d、q轴抛载试验的不足,提出了任意工况下一次性抛载试验参数辨识方法.通过分析同步发电机抛载试验动态过程,建立了任意工况下一次性抛载试验d、q轴传递函数模型.考虑到传递函数输入/输出均可测量,通过积分变换将微分方程转化为积分方程,将同步发电机任意工况抛载试验传递函数模型转化为线性回归模型,在此基础上通过分析参数可辨识性和引入多新息最小二乘辨识算法,解决了同步发电机物理参数辨识问题.算例结果验证了该方法的有效性.     

基于抛载法和BPA仿真的发电机参数辨识方法

发电机参数是影响电力系统仿真计算准确性的关键因素.为了提高发电机参数的准确性,针对作图法辨识发电机参数精度不高的缺点,提出了一种基于抛载法和BPA仿真的发电机参数辨识方法.基于抛载法的基本原理,现场对某台机组进行了d/q轴抛载试验,并利用BPA软件建立与抛载试验相同工况的仿真模型,通过仿真结果与现场试验的对比分析,辨识得到发电机的d、q轴参数.仿真结果表明,利用该方法辨识出的参数切合实际、精度较高.     

基于时域仿真抛载法的同步发电机参数辨识方法

获取准确的发电机参数是提高电力系统仿真计算准确性的重要依据,有利于电网的安全稳定运行。应用抛载法对发电机的抛载过渡过程进行理论分析,基于时域仿真抛载法提出同步发电机参数的辨识方法。利用抛载法进行发电机现场试验,获得发电机空载、灭磁和d/q轴抛载试验数据并进行分析处理。模拟现场试验工况,建立发电机空载、灭磁及d/q轴抛载的时域仿真模型,将仿真结果与试验结果进行对比分析,辨识得到全套发电机参数。为验证提出参数辨识方法的有效性,建立发电机异步自励磁仿真模型并利用辨识参数与原厂提供参数进行异步自励磁工况仿真,将仿真结果与试验波形进行对比,表明辨识参数具有更高的准确性。     

基于PMU实测数据的同步发电机参数在线辨识方法

由于试验条件与发电机运行的实际工况有较大差异,常规的电机试验难以得到与饱和、涡流等密切相关的发电机动态参数的准确值,满足不了离线和在线安全分析及控制的要求。将PMU上传的定子电压和励磁电压量测作为输入信号、定子电流和励磁电流作为输出信号,基于PMU实测数据和同步发电机派克模型,考虑定子绕组暂态过程,实现了同步发电机原始参数的辨识。电力系统实际算例表明,与设计参数相比,基于该参数辨识结果的仿真曲线与实测发电机动态曲线的拟合程度明显要高,所提方法能够有效提高同步发电机的参数辨识精度。     

基于改进静止频率响应试验的同步电机参数辨识

针对同步电机参数辨识问题,以全电流为状态变量,研究同步电机d、q轴磁链与定子电流及励磁电压的关系,建立电机的数学模型。通过分析静止频率响应试验曲线,获得不同频率下各测试参数的增益和相位,替换d、q轴电磁参数特性传递函数方程中的相关部分,简化电机数学模型及其状态空间方程。基于励磁和定子回路开路时电机状态的分析结果,改进数据处理过程,辨识电机参数,对比采用其它方法测取的结果,有较好的一致性,所提参数辨识方法的有效性得以验证。     

抛载试验和数值差分在发电机参数辨识中的应用

为解决抛载法用于自并励发电机参数辨识时因励磁电压变化导致的辨识不准确问题,提出了基于抛载试验和数值差分的发电机参数辨识方法。该方法采用抛载试验和时域辨识法相结合的方式开展参数辨识;同时,为形成参数迭代过程中的雅克比矩阵,利用数值差分的方法计算机端电压对各参数的轨迹灵敏度,较好地解决了抛载时刻轨迹灵敏度的初值问题。由于抛载试验电气量可观测性强,该方法能较好地克服环境噪声的干扰;同时,时域辨识法理论严密,能充分计及自并励机组抛载后励磁电压变化对辨识结果的影响。辨识实例表明该方法简单易行,具有较强的工程实用价值。     

考虑d轴抛载试验中测量噪声的同步发电机d轴参数估计

提出了一种在d轴抛载试验条件下估计同步发电机d轴参数的新方法。首先,利用q轴电压、励磁电流以及它们的数值积分,构建线性回归方程。其次,利用辅助变量法求解带有测量噪声的回归方程的系数。最后,根据回归系数计算d轴参数。算例的测试结果表明,所提方法比现有的图形法和数值优化法有更好的估计性能。     

A method to determine direct‐ and quadrature‐axis inductances of permanent magnet synchronous motors

The equivalent circuit constants of permanent magnet synchronous motors are needed in the calculation of operation characteristics, construction of a control system, etc. These constants can be computed from the data on structural form and materials. However, measurements are necessary to obtain highly precise values. Methods for measurement of the d‐ and q‐axis inductances can be roughly divided into rotational and standstill methods. The standstill methods have the advantage that they are easy to carry out. However, it is difficult to consider magnetic saturation and distortion of the change in the armature winding inductance. The accuracy of the standstill method can be improved if these effects can be readily taken into account. This paper describes a standstill method for measuring accurate d‐ and q‐axis synchronous inductances of permanent magnet synchronous motors. By utilizing the fact that the EMF interference terms in the motor voltage equation considering the distortion of the inductance change are equal to zero when the rotor is in a specific position, the proposed method determines the inductances considering both magnetic saturation and inductance distortion effects from simple off‐line standstill testing. In addition, this method is capable of taking cross‐magnetic saturation into account when used with the necessary testing equipment. The proposed method was implemented on a 0.4‐kW interior permanent magnet synchronous motor with concentrated stator winding. The validity of the proposed method was demonstrated by comparing the measured and calculated results of the no‐load and on‐load characteristics. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(3): 41–50, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20969     

采用旋转因子法的同步电机模型

提出了一种新的适用于电力系统机网暂态过程数值仿真的有阻尼绕组同步电机模型。通过采用“旋转因子法”对同步电机的电压方程组进行差分化，成功地消除了因旋转电势引起的，存在于同步电机直轴电压方程和交轴电压方程之间的耦合，导出了相互解耦的直轴和交轴瞬态等值电路。文末的算例通过比较该模型与EMTP模型的仿真结果，证明这种新模型是正确的，其仿真算法比常用的EMTP算法更精确、更稳定。     

同步磁阻电机dq轴交叉耦合饱和电感模型参数寻优方法

同步磁阻电机的直轴电感Ld与交轴电感Lq随直轴电流id与交轴电流iq的非线性变化,极大地影响矢量控制特性。同步磁阻电机驱动器中用8个常数构建了电机dq轴交叉耦合饱和电感模型,为了推算其最优参数,在横向叠片各向异性转子同步磁阻电机的设计参数基础上,采用小电流常规方法测量Ld、Lq电感值,建立带权重的最小方均差模型,并针对不同目标函数设定相应的权重,采用改进和声搜索优化算法进行迭代,获得了与电机真实信息较为接近的优化解。其有效性通过电机对拖负载实验得以验证。     

基于感应励磁的混合励磁同步发电机性能

针对感应励磁发电机结构简单但励磁容量有限,永磁同步发电机磁场难以调节的问题,研究了一种将二者励磁功能相结合的混和励磁发电机。气隙中大部分磁场由转子上的永磁体提供,当需要调磁时,通过定子直流绕组与转子上感应绕组的感应作用,在感应绕组上获得调节磁动势,实现发电机磁场的调节。转子上两种励磁源为并联关系,调磁磁路磁阻小,无电刷-集电环系统,保证了发电机的结构简单、可靠性。在原理分析的基础上,使用二维有限元法对电机的磁场调节能力和负载特性进行分析,并进行了样机实验。有限元分析与实验结果都表明,与同结构参数的永磁同步发电机相比,混合励磁同步发电机具有灵活磁场调节能力;而相对于同一定子励磁磁动势的感应励磁发电机,该发电机输出容量大幅度提高,克服了感应励磁不适用于大容量发电的问题。     

A brushless three-phase synchronous motor using the armature winding as both load and DC excitation winding

This paper presents a new brushless three-phase synchronous motor which has no exciter. The technique applied to the motor provides an effective way for conventional brushless synchronous motors to simplify the system configuration. The stator of the motor is equipped with a double-star connected armature winding which has two neutral points. The rotor is a cylindrical one, which is equipped with a two-phase field winding. The field winding is connected with shaft-mounted rectifiers. A dc voltage is applied to the two neutral points of the armature winding to obtain the rotor excitation when the motor is operated at synchronous speed. At that time. the armature winding acts as a stator dc exciting winding while also acting as a load winding. In this paper the principle and characteristics of the motor are described. and the experimental results are shown. It is confirmed that with a 2-kW experimental machine, the proposed motor has good performance. For example, by adjusting the stator dc current, this motor power factor can easily be controlled within a wide range.     

基于交替迭代优化的同步调相机电气参数分步辨识方法

300 Mvar快速动态响应同步调相机广泛应用于特高压直流输电.为准确辨识调相机器模型参数,提出一种基于交替迭代优化的电气参数分步联合辨识方法.采用考虑饱和特性的六阶实用电机模型,设计了包含励磁阶跃扰动、甩负荷扰动和机端电压扰动的小扰动实验方案;基于交替迭代方向乘子法和轨迹灵敏度分析法,制定了采用三组小扰动实验数据联合...     

Determination of effective air-gap length of synchronous reluctance motors (SynchRel) from experimental data

The usage of synchronous reluctance motors (synchRel) has been gaining importance in many industry applications mainly because of their many advantages over other motors. The performance of a synchRel is greatly dependent on its effective air-gap lengths along the d and q axes. Hence, in this paper, an attempt has been made to obtain the effective air-gap lengths of the machine from the experimental values of the d and q axes reactances and by considering the higher permeance and winding space harmonics. To determine the air gaps, these reactances are compared with their corresponding expressions involving the coefficients of magnetizing and mutual inductances of the stator windings, obtained by using the winding function approach (WFA). Using these air-gap values, a more realistic model of the machine is obtained. A comparative study has been carried out with different permeance and winding space harmonics. The computed q-axis air-gap length seems to be much more sensitive to the operating point and the leakage inductance, compared to the computed d-axis air-gap length. Experimental values near the no-load condition have been considered to minimize flux barrier effects, as WFA cannot simulate these effects without changing the length of the pole arc. The effective air gaps of another salient-pole synchronous machine with damper bars have also been determined by considering the higher permeance and winding space harmonics, when run as a synchRel (without field excitation). This machine did not have flux barriers, and, hence, the results seem to be more accurate. Finally, the performance of the simulated synchRel has been compared with the experimental results.     

无刷双馈电机的稳态转矩-角特性

简述了从无刷双馈电机的电机变量的方程推导无刷双馈电机的双轴数学模型,在双轴模型的基础上,仿真研究了稳态运行时ｄ－ｑ模型下功率绕组与控制绕组间电压相角差与电机电磁转矩的关系,揭示了无刷双馈电机稳态运行时具有同步电机特性,并为该电机运行状态的控制提供了依据。     

A new self-excitation scheme for three-phase synchronous generators

A new self-excitation scheme has been developed for three-phase synchronous generators. The generator that uses this scheme behaves as a flat-compound machine without automatic voltage regulators. The stator of the generator is provided with an armature winding that generates the fundamental and 2nd-harmonic mmfs. The rotor is equipped with a field winding and a harmonic winding. The harmonic winding is magnetically coupled to the 2nd-harmonic mmf produced by the armature winding. The current flows in the stator armature winding by way of a three-phase set of capacitors connected across its three-phase terminals and the ac voltage is induced in the rotor harmonic winding due to the armature 2nd-harmonic mmf. By connecting the harmonic winding to the field winding through a rectifier circuit, self-excitation of the generator is obtained. This excitation scheme is both self-excited and brushless, and no exciter is required. Additionally, voltage regulation due to load variation can be improved by connecting suitable capacitors. In this paper the operating principle and circuit configuration of the generator are explained and the experimental results using a 1-kVA prototype machine are shown. The generator characteristics are theoretically clarified by approximate analysis, and appropriateness of the theory and the usefulness of the proposed scheme are experimentally confirmed.