轴向磁场调制型磁力齿轮设计与验证

与传统机械齿轮箱不同,轴向磁力齿轮采用电磁变级变速原理,使得输入端和输出端之间无机械接触,具有无磨损、不需润滑、免维护等优点.采用二维动态场与三维静态场有限元法设计了磁力齿轮,样机试验数据比较表明,该有限元算法准确,样机设计合理可行.     

基于复转矩系数法的双馈风电机组阻尼转矩建模

为研究转子侧变流器及其控制系统对双馈风电机组阻尼的影响机理，考虑机械转矩、电磁转矩、暂态电势、转子侧变流器控制、电压控制以及角度偏移等环节，构建小干扰状态下机组动态模型；然后基于复转矩系数法，推导双馈风电机组阻尼转矩和同步转矩表达式，得到阻尼转矩与机组振荡频率、风速、机组机械参数、电气参数及控制系统参数有关，转子侧变流器内环、外环控制参数之间相互耦合，共同影响机组的阻尼；最后，通过仿真对所建数学模型进行验证。仿真验证结果表明：在不同振荡频率下，所建模型均具有适用性。     

大型双馈风力发电系统小信号动态建模及附加阻尼控制器设计

由于风电场输出功率的波动性及远距离输电等原因,大规模风电场接入互联电力系统后会面临不同区域电网间的低频振荡问题。建立了大型双馈风力发电系统的小信号动态模型,该模型包括风力机及传动系统动态方程、异步发电机动态方程、变频器动态方程以及变频器控制系统动态方程4个部分,具有一般性。以双馈风力发电机转子侧变流器有功功率参考值为输入,以互联电力系统区域间同步发电机功角差值为输出,通过系统辨识方法得到二者间的开环传递函数。在此基础上,利用极点配置方法,设计了双馈风力发电机的附加阻尼控制器。非线性时域仿真表明,配备了阻尼控制器的大规模风电场能够有效抑制互联系统的低频振荡,增加互联系统的阻尼。     

ALA转子磁阻同步电动机的动态不稳定性

采用小信号分析法研究了ALA转子磁阻同步电动机开环运行时的动态不稳定性问题 ,导出了ALA转子磁阻同步电动机电磁阻尼转矩系数的解析表达式 ,分析了电动机在小值振荡条件下的电磁阻尼特性 ,提出ALA转子电动机的动态不稳定性在电动机电源频率略大于电动机振荡的自然频率时产生。理论分析与实验结果相符。     

直驱永磁同步风力发电系统的阻尼系统设计

1直驱永磁风力发电系统的阻尼系统应用由于永磁同步发电机(PMSG)定子和转子磁场之间没有相对运动,不能在阻尼绕组中产生感应电压;再者,PMSG转子上没有磁场绕组,也不存在磁场绕组中产生感应电流或阻尼作用;另外,多极低速永磁同步发电机的极距很小,不能采用传统的阻尼绕组去抑制功率角振荡,因此连接到直驱风电系统中PMSG是没有阻尼系统的。又     

隐极同步电动机转矩可控性与解偶性分析

交交变频同步电动机矢量控制系统已广泛应用于轧钢机主传动,对其控制原理的研究具有重要的意义.依据隐极同步电动机dq轴系和气隙磁链定向的数学模型,对转矩的解偶性和可控性进行了分析,还对阻尼绕组的影响进行了分析,认为阻尼绕组有助于减少动态速降并可稳定动态过渡过程,无阻尼绕组传动系统的转矩解偶、控制方便,但动态时可能发生震荡.     

基于VSG的改进型虚拟阻尼控制策略与特性分析

传统虚拟同步发电机（VSG）控制策略可模拟同步发电机的惯量和阻尼特性,但会使并网逆变器产生功率振荡和功率偏差。针对虚拟同步发电机动态过程中存在的功率振荡问题,提出一种基于VSG的改进型虚拟阻尼控制策略来抑制功率振荡。首先介绍了传统阻尼绕组与常系数虚拟阻尼绕组抑制功率振荡的原理及特性,其次利用根轨迹法分析设计了改进型虚拟阻尼控制策略的参数,最后搭建仿真模型验证了该控制的有效性及准确性。     

高性能磁力齿轮传动扭矩与效率的数值计算

为了获得高性能磁力齿轮的传动扭矩和效率等性能参数,利用Maxwell 2D软件对其进行静态、动态有限元模拟计算。计算出内磁转子、外磁转子以及调磁极片的静态扭矩;定义内、外磁转子分别以对应的转速运行,得出其功率损耗,进而得到其扭矩损耗;定义了磁力齿轮的3种运行方式,根据静态扭矩以及扭矩损耗的结果,推算出各种运行方式下效率的计算公式并分析其变化规律。分析的结果可以为磁力齿轮的设计制作提供依据。     

3 MW同步发电机阻尼绕组设计与超瞬态电抗性能验证

当一款发电机定转子主要尺寸定型后,转子的阻尼绕组性能是影响发电机超瞬态电抗的最主要因素。在不同的工况下,用户对发电机的超瞬态电抗的性能有不同的要求。通过阻尼绕组的调整基本可实现超瞬态电抗的调整。通过对1台3 MW无刷同步发电机转子阻尼绕组采用不同材质或不同的阻尼条数的设计方案,对超瞬态电抗值进行计算和分析,并通过低电压突然短路测试方式验证了不同方案对超瞬态电抗值的影响,以获得最佳的阻尼绕组设计方案。     

Halbach阵列同心式磁力齿轮参数分析与优化设计

直驱式同心式磁力齿轮在低速大转矩领域有广泛的应用前景。为获得较正弦分布气隙磁场,所用永磁体采用Halbach阵列充磁,用二维全局解析法计算同心式磁力齿轮磁场分布;分析了调磁环铁心宽度、调磁环高度及外转子轭部厚度等参数与磁力齿轮最大静态转矩之间的关系。磁场全局解析法计算结果与有限元分析结果一致性较好,验证了解析模型的正确性;根据参数分析结果,制作了一台内转子4对极、外转子17对极的Halbach阵列同心式磁力齿轮样机,样机试验结果表明,合理选择结构参数可以提高磁力齿轮的转矩密度,对磁力齿轮的设计提供一种有益参考。     

Performance of a synchronous generator with bridge rectified output

The performance of a salient pole synchronous generator connected to a bridge rectifier load is derived from the fundamental machine equations. The generator is fitted with both direct- and quadrature-axis damper windings, and the bridge rectifier load is fully controlled. Explicit equations are obtained for displacement angle, commutation angle, phase voltages, armature currents, field current and damper winding currents. From these equations, the performance of generators with and without damper windings, connected to controlled or uncontrolled bridge rectifier loads can be predicted from given load current, field current, generator speed, bridge delay angle and machine parameters. Comparative experimental and theoretical results are given.     

A New Brushless Half-Speed Synchronous Motor with Q-Axis Squirrel-Cage Damper Winding Driven by Voltage Source Inverter

A new brushless half-speed synchronous motor combined with a voltage source inverter is presented. The diode is inserted into one phase of the stator winding, and then the stationary magnetic field is superimposed on the revolving field. The rotor structure of the proposed motor is composed of the quadrature-axis (q-axis) squirrel-cage damper windings on the salient poles. By superimposing a stationary magnetic field on the stator, the motor is compelled to run at exactly half synchronous speed. For purposes of direct comparison the machine is tested with various configurations of damper windings. The experimental results are shown, and it is proved that the motor has excellent performance. The proposed brushless synchronous motor is very simple, robust, and maintenance-free.     

磁场调制式磁力齿轮及其有限元计算

为避免机械齿轮振动,或要在分开物体间传递力矩,可以采用磁力齿轮传动装置。设计该磁力传动装置时需要对其设计参数进行精确计算。在电机设计时,使用有限元方法对一种大力矩磁力齿轮——磁场调制式磁力齿轮进行了磁场计算,为设计该磁力齿轮提供了有力的工具。     

同步发电机阻尼绕组和磁路饱和对低频振荡阻尼的影响

采用特征值分析法研究同步发电机阻尼绕组以及磁路饱和对低频振荡阻尼的影响。建立了同步发电机三阶以及考虑阻尼绕组的六阶小扰动线性化模型,并在模型中考虑了磁路饱和效应。为详细分析同步发电机阻尼绕组和磁路饱和对低频振荡阻尼的影响,采用了简化的单机无穷大系统。计算表明,在分析低频振荡问题时:同步发电机三阶模型不宜用于分析进相或轻载运行的机组,这一结论和是否安装电力系统稳定器(PSS)以及是否忽略磁路饱和无关;忽略磁路饱和的同步发电机三阶模型在额定工况附近具有比较高的准确性;磁路饱和对六阶模型的影响较小,但是对于含PSS的进相运行机组,不宜忽略磁路饱和;为得到准确的结论,建议在同步发电机模型中考虑阻尼绕组和磁路饱和的影响。     

阻尼绕组对磁场定向控制交－交变频同步电机动态行为的影响

本文在交－交变频磁场定向控制同步电机调速系统数学模型的基础上，研究了阻尼绕组对交－交变频同步电机动态行为的影响．结果指出．阻尼绕组能有效地抵消动态电枢反应，加快定子电流响应，提高电机的过载能力．从改善系统的动态特性出发，应选择全阻尼结构。     

Development of a high-performance magnetic gear

This paper presents calculation and measurement results of a high-performance permanent-magnetic gear. The analyzed permanent-magnetic gear has a gear ratio of 5.5 and is able to deliver 27 N/spl middot/m. The analysis has shown that special attention needs to be paid to the system where the gear is to be installed because of a low natural torsion spring constant. The analyzed gear was also constructed in practice in order to validate the analysis and predict the efficiency. The measured torque from the magnetic gear was only 16 N/spl middot/m reduced by the large end-effects. A systematic analysis of the loss components in the magnetic gear is also performed in order to figure out why the efficiency for the actual construction was only 81%. A large magnetic loss component originated in the bearings, where an unplanned extra bearing was necessary due to mechanical problems. Without the losses of magnetic origin in the bearings and less end-effects caused by relatively short stack, an impressive efficiency estimated at 96% can be obtained. Comparison with classical mechanical gears has shown that the magnetic gear has a better efficiency and a comparable torque per volume density. Finally, it is concluded that the results in this paper may help to initiate a shift from mechanical gears to magnetic gears.     

三种充磁方式轴向磁齿轮的磁场和转矩特性比较

依据永磁体充磁方向和排列方式的不同,轴向磁齿轮可分为轴向充磁磁齿轮、聚磁式轴向磁齿轮和Halbach式轴向磁齿轮。采用3D有限元法对三种轴向磁齿轮的磁场、转矩特性和轴向力进行了比较。基于气隙磁场的谐波分析,利用公式计算出各次谐波磁场产生的转矩和轴向力,得出各次谐波磁场对转矩传递和轴向力的作用。比较表明,聚磁式轴向磁齿轮的转矩能力和永磁体利用率最大,比轴向充磁磁齿轮提高了17.5%和32.6%,比Halbach式轴向磁齿轮提高了2%和15.1%。Halbach式轴向磁齿轮的气隙中引起转矩波动的磁场谐波的幅值最小,转矩波动也最小。轴向充磁磁齿轮低速转子的轴向力最小,比聚磁式轴向磁齿轮小38.3%,比Halbach式轴向磁齿轮小32.7%。     

On the Use of Electromechanical Systems for Limiting Dynamic Loads in Spring Mechanisms

Active methods for damping the oscillations and limiting the dynamic loads of spring machine elements that are implemented owing to the additional force effects created by an electric drive providing the reduction of maximum work in spring gears of operated machinery were studied. The main parameters and energy characteristics of electromechanical systems that affect the efficiency of using of active means of dynamic load limitation by an electric drive in spring elements of mechanical gears were determined. It was shown that the maximum value of electric-engine current and its rate of change can decrease the efficiency of the active dynamic load limitation in machines by an electric drive and impede its practical implementation. Analytic equations for calculating the minimax torque (current) values of an engine and EMF of its supplying converter required for an effective decrease of the dynamic loads in spring machine elements were derived. The effects of the hardware and electric-drive parameters on the efficiency of decreasing dynamic loads in spring mechanical gears was specified. Research was performed to determine the efficiency and range of application of the active methods of dynamic load limitation in spring gears of machines using the existing electric drives. The results of the research were used in the implementation of active means of dynamic load limitation by an electric drive in spring gears of the thrust mechanism of an EKG-4.6B mine excavator and the digging mechanisms of EKG-20 excavators, as well as for decreasing the speed and force oscillations of the operating parts of balanced MP-100 manipulators and the weightless environment of zero-gravity simulators for training astronauts.     

无源自适应磁流变阻尼器磁致伸缩逆效应的建模与实验研究

制作了一种基于磁致伸缩逆效应的无源自适应磁流变阻尼器,通过超磁致伸缩材料的逆效应,将外加机械能的变化转化为阻尼器内部磁能的变化,进而控制阻尼间隙处阻尼力的大小,达到预期抗拉目的.为了研究活塞杆上下振动过程中由超磁致伸缩材料引起的阻尼器内部磁场分布的变化规律,应用磁机械效应方法定律对阻尼器的关键技术——磁致伸缩逆效应建立...     

A Novel Magnetic Harmonic Gear

Magnetic gears offer several advantages compared to mechanical gears in terms of reduced maintenance, improved reliability, and inherent overload protection while having a high efficiency. This paper describes the principle of operation of a novel form of magnetic gear, which is particularly suited to applications for which a high gear ratio is required. The performance capability of such a magnetic gear is investigated, and it is shown that it transmits a ripple-free torque and that an active torque density of up to 150 $hbox{kN}cdot hbox{m/m}^{3}$ per stage can be achieved when high-energy permanent magnets are employed. Simulation results on this novel gear are verified by experimental measurements on a prototype.