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1.
针对永磁同步风力发电系统的混沌运动现象, 提出了基于系统Hamilton模型的H控制方案, 使得系统脱离混沌, 运行稳定. 首先将永磁同步风力发电系统模型经过一系列状态变换, 转化为类Lorenz经典数学模型, 并验证了系统在一定参数区域内存在混沌现象. 随后基于Hamilton系统充分利用系统物理结构和无需补偿“无功力”的优点, 建立了混沌系统的Hamilton模型, 并考虑了系统存在外扰情况下的H控制方法. 本文所设计的控制器  相似文献   

2.
郝建红  汪筱巍  张恒 《物理学报》2014,63(22):220203-220203
<正>针对永磁同步电动机混沌系统,考虑受不确定因素的影响,对其数学模型采用基于微分几何理论的精确反馈线性化法,建立鲁棒控制模型,设计鲁棒控制器,实现永磁同步电动机混沌系统的鲁棒镇定和输出跟踪控制.数值仿真的结果证明了所提出方法的有效性及控制器的鲁棒性.  相似文献   

3.
郑刚  邹见效  徐红兵  秦钢 《物理学报》2011,60(6):60506-060506
以直驱型永磁同步风力发电机为研究对象, 推导了发电机在参数不确定以及风速扰动情况下的数学模型,验证了系统在某些参数及工作条件下会呈现出混沌属性. 并提出了直驱型永磁同步风力发电机混沌运动下的基于反步自适应控制算法,并对其进行了仿真, 仿真结果表明,所提出的算法对于具有参数不确定以及风速干扰的直驱型风力发电系统具有较好的鲁棒性. 关键词: 风力发电 直驱型永磁同步风力发电机组 混沌控制 反步自适应控制  相似文献   

4.
王益军  王六定  杨敏  刘光清  严诚 《物理学报》2010,59(7):4950-4954
运用基于第一性原理的密度泛函理论,系统研究了处于外电场中分层掺B并吸附不同数目H2O碳纳米管体系的结构稳定性和电子场发射性能. 研究表明:第3层掺B并吸附5个H2O的B3CNT+5H2O体系结构最稳定,管帽处Mulliken电荷最密集,尤其与单独掺B的B3CNT和单独吸附H2O的B3CNT+5H2O相比,其Fermi能级处态密度分别  相似文献   

5.
韦笃取  张波  丘东元  罗晓曙 《物理学报》2009,58(9):6026-6029
基于LaSalle不变集定理,设计自适应混沌控制器对永磁同步电动机中的混沌进行控制.由于该控制器能自动跟踪平衡点,无需预先知道系统平衡点位置,不需要改变受控系统原有的结构, 因此设计直接简便,控制代价小,易于工程实现.仿真结果表明了该方法的有效性. 关键词: LaSalle不变集定理 自适应律 混沌控制 永磁同步电动机  相似文献   

6.
成泰民  葛崇员  孙树生  贾维烨  李林  朱林  马琰铬 《物理学报》2012,61(18):187502-187502
利用不变本征算符法, 计算低温下自旋为1/2的XY模型一维亚铁磁棱型链系统的元激发谱, 讨论在此系统中不同的特殊情形下的元激发能量, 从而给出体系的三个临界磁场强度的解析解HC1, HC2, Hpeak. 分析不同外磁场下 体系的磁化强度随温度的变化规律, 发现三个临界磁场强度的解析解HC1, HC2, Hpeak是正确的, 并从三个元激发对磁化强度的贡献进行了说明. 低温下磁化强度随外磁场的变化呈现1/3磁化平台. 体系的磁化率随温度或者外磁场的变化都出现了双峰现象. 这说明双峰源于二聚体分子内电子自旋平行排列的铁磁交换作 用能和二聚体与单基体分子间电子自旋反平行排列的反铁磁交换作用能, 热无序能, 外磁场强度相关的自旋磁矩势能之间的竞争.  相似文献   

7.
陈强  南余荣  邢科新 《物理学报》2014,63(22):220506-220506
针对部分状态不可测的永磁同步电机混沌系统, 结合自适应滑模控制和扩张状态观测器理论, 提出一种基于扩张状态观测器的永磁同步电机自适应混沌控制方法, 取消了系统所有状态完全可测的限制. 通过坐标变换, 将永磁同步电机混沌模型变为更适宜控制器设计的Brunovsky标准形式. 在系统部分状态和非线性不确定项上界均未知的情况下, 基于扩张状态观测器估计系统未知状态及不确定项, 并设计自适应滑模控制器, 保证系统状态快速稳定收敛至零点. 仿真结果表明, 该控制器能够改善滑模控制的抖振问题以及提高系统鲁棒性. 关键词: 永磁同步电机 混沌控制 扩张状态观测器 自适应滑模  相似文献   

8.
利用具有同步辐射源的反射式飞行时间质谱仪,研究甲基环己烷的真空紫外光电离和光解离. 观测到母体离子C7H14+和碎片离子C7H13+,C6H11+,C6H10+,C5H10+,C5H9+,C4H8+,C4H7+和C3H5+的光电离效率曲线. 测定甲基环己烷的电离能为9.80±0.03 eV,通过光电离效率曲线确定其碎片离子的出现势. 在B3LYP/6-31G(d)水平上对过渡态、中间体和产物离子的优化结构进行表征,并使用G3B3方法计算其能量. 提出主要碎片离子的形成通道. 分子内氢迁移和碳开环是甲基环己烷裂解途径中最重要的过程.  相似文献   

9.
H+CH3OH作为典型的多通道反应,在燃烧和星际中起着重要的作用. 本文基于在UCCSD(T)-F12a/AVTZ水平上计算的大量数据点,构建了该体系的全维精确势能面,并基于该势能面,研究了不同产物通道的模式特异动力学. 结果表明,O-H 伸缩、沿C-O轴的扭转以及C$-$H伸缩等模式的振动激发对H2+CH3O、H2+CH2OH、H2O+CH3和H+CH3OH四个产物通道有着不同的影响. 该研究有助于理解具有多个产物通道的复杂反应的模式特异动力学,进而帮助控制其竞争反应.  相似文献   

10.
杨锦辉  宋君强 《物理学报》2012,61(17):170511-170511
在非线性误差增长理论框架下研究了混沌系统平均初始误差增长饱和特性 以及误差饱和值同系统可预报期限的关系.首先探索了Lorenz96系统中平均相对初始误差增长饱和规律, 发现平均相对初始误差增长饱和值同初始误差的自然对数存在简单的线性关系: 其二者自然对数之和为一常量,且该常量同初始误差无关.实验表明该结论对其他混沌系统也适用. 因此对给定混沌系统,在计算出和常数后可以外推得到任意固定初始误差的平均相对误差增长饱和值. 为进一步研究误差饱和值同可预报期限的关系,给出了平均绝对误差增长的定义. 理论分析表明混沌系统平均绝对误差增长也会达到饱和.其饱和值为常量, 与初始误差无关,混沌系统控制参数确定,饱和值就固定.依据上述研究, 最后给出一个定量计算可预报期限的模型Tp=1/ln(Es/δ0)+c, Es为绝对误差增长饱和值.实验研究表明对于复杂的高阶混沌系统,该预报期限模型都能较好地适用.  相似文献   

11.
The attenuation of the low frequency noise produced by the car engine vibration has been the major concern of the automotive community with the objective to increase the comfort of the driver and the passengers. The chassis subframe is the part responsible for transmission of the engine vibration to the car body through the engine mounts. At the beginning of this paper, we briefly describe the test rig we used and which has been experimentally investigated by using system identification. Then the experimental results of the feedforward control strategy and the achieved performance are briefly presented. These results are then compared to the feedback control method utilizing H strategy which allows us to design a robust controller requiring less sensors. Furthermore, a broadband noise attenuation could be achieved by using a robust feedback controller in the real time test.  相似文献   

12.
张洪斌  于永斌  张健 《中国物理 B》2010,19(8):80509-080509
<正>This paper studies the problem of robust H_∞control of piecewise-linear chaotic systems with random data loss. The communication links between the plant and the controller are assumed to be imperfect(that is,data loss occurs intermittently,which appears typically in a network environment).The data loss is modelled as a random process which obeys a Bernoulli distribution.In the face of random data loss,a piecewise controller is designed to robustly stabilize the networked system in the sense of mean square and also achieve a prescribed H_∞disturbance attenuation performance based on a piecewise-quadratic Lyapunov function.The required H_∞controllers can be designed by solving a set of linear matrix inequalities(LMIs).Chua's system is provided to illustrate the usefulness and applicability of the developed theoretical results.  相似文献   

13.
D.H. Ji  J.H. Koo  S.C. Won  Ju H. Park 《中国物理 B》2011,20(7):70502-070502
We consider an H ∞ synchronization problem in nonlinear Bloch systems.Based on Lyapunov stability theory and linear matrix inequality formulation,a dynamic feedback controller is designed to guarantee asymptotic stability of the master-slave synchronization.Moreover,this controller reduces the effect of an external disturbance to the H ∞ norm constraint.A numerical example is given to validate the proposed synchronization scheme.  相似文献   

14.
The spectrum of the ν7 band of cis-ethylene-d2 (cis-C2H2D2) has been recorded with an unapodized resolution of 0.0063 cm−1 in the 740-950 cm−1 region using a Bruker IFS 125 HR Fourier transform infrared spectrometer. By fitting 2186 infrared transitions of ν7 with a standard deviation of 0.00060 cm−1 using a Watson’s A-reduced Hamiltonian in the Ir representation, accurate rovibrational constants for ν7 = 1 state have been derived. The band center of ν7 has been found to be 842.20957 ± 0.00004 cm−1. In a simultaneous fit of 1331 infrared ground state combination differences from the present ν7 transitions, together with 22 microwave frequencies, ground state constants have been improved. The rms deviation of the ground state fit was 0.00027 cm−1.  相似文献   

15.
The analysis of the ν3/ν7/ν9 bending triad of SO2F2 has been recently performed with the Watson’s Hamiltonian up to octic terms employing 79 rovibrational parameters but including only the first order Coriolis interaction terms, fixed to ab initio values [H. Bürger, J. Demaison, F. Hegelund, L. Margulès, I. Merke, J. Mol. Struct. 612 (2002) 133-141]. Since SO2F2 is a quasi-spherical top, it can also be considered as derived from the sulfate ion. We have thus developed a new tensorial formalism in the O (3) ⊃ Td ⊃ C2v group chain [M. Rotger, V. Boudon, M. Loëte, J. Mol. Spectrosc. 216 (2002) 297-307]. This approach allows a systematic development of rovibrational interactions and makes global analyses easier to perform even for complex polyad systems. We present here an application of this model to the analysis of the bending triad, with the same set of microwave assignments and almost the same set of infrared assignments as in the previous study of Bürger et al. It appears that we need to expand our Hamiltonian to a lower degree than the “classical” one (six instead of eight) when including also the second order Coriolis interactions. Our fit does not include more parameters. Furthermore, all of them are determined and the standard deviation of the rotational transitions is twice smaller. The analysis has been performed thanks to the C2v TDS program suite, which is freely available at the URL: http://www.u-bourgogne.fr/LPUB/c2vTDS.html.  相似文献   

16.
In designing finite horizon discrete time H controllers, the associated H-Riccati difference equations must be solved. But the Riccati equation has a non-negative solution only when γ−2 is small enough. So it is important to get the upper bound of the parameter, i.e., the critical value that ensures the existence of the solution to the Riccati equation. The solution sequence of the Riccati difference equation can be constructed by the conjoined basis of an associated linear Hamiltonian difference system. Based on this expression and the Hamiltonian difference system eigenvalue theorems, the equivalence between the critical value and the first order eigenvalue of the linear Hamiltonian difference system is presented. Since the critical value is also shown to be the fundamental eigenvalue of a generalized Rayleigh quotient, an extended form of Wittrick-Williams algorithm is presented to search this value.  相似文献   

17.
18.
Frequencies of pure rotational transitions in the v2 = 1 vibrationally excited state of H216O were measured with a tunable far-infrared spectrometer in the frequency range of 0.5-5 THz. Molecular parameters of Watson’s A-reduced Hamiltonian have been obtained to reproduce the observed frequencies.  相似文献   

19.
In this paper, we seek to develop an efficient controller for vibration reduction in a small square plate clamped on all edges. The plate mimics a piece of an aircraft's skin. Small plate size results in higher natural frequencies than normally investigated in literature. Such high-frequency systems are more susceptible to time delays. In addition, the control system must be able to operate over a wide range of temperatures, a requirement for in-flight vibration suppression systems. We investigate two methodologies (sliding mode control, and an adaptive H control) for control over a wide range of temperatures. Theoretical and experimental studies are conducted and produced varying results. The best theoretical and experimental results are obtained with the adaptive H controller.  相似文献   

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