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On the improvement design of dynamic characteristics for the roller follower of a variable-speed plate

Hui Ching FAN, Hong Sen YAN

《机械工程前沿(英文)》 2012年 第7卷 第1期   页码 5-15 doi: 10.1007/s11465-012-0310-y

摘要:

Without modifying the cam contour, a cam mechanism with a variable input speed trajectory offers an alternative solution to flexibly achieve kinematic and dynamic characteristics, and then decrease the follower’s residual vibration. Firstly, the speed trajectory of cam is derived by employing Bezier curve, and motion continuity conditions are investigated. Then the motion characteristics between the plate cam and its roller follower are derived. To analyze the residual vibration, a single degree of freedom dynamic model of the elastic cam-follower system is introduced. Based on the motion equation derived from the dynamic model, the residual vibration of the follower is yielded. The design procedure to improve the kinematic and dynamic motion characteristics is presented and two design examples with discussions are provided. Finally, the simulations of the kinematic and dynamic models by ADAMS are carried out and verified that the design models as well as the performances of the mechanism are feasible.

关键词: cam mechanism     variable input speed     kinematic design     dynamic design     optimal design    

Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault

Hamed HABIBI, Hamed RAHIMI NOHOOJI, Ian HOWARD

《机械工程前沿(英文)》 2017年 第12卷 第3期   页码 377-388 doi: 10.1007/s11465-017-0431-4

摘要:

Power maximization has always been a practical consideration in wind turbines. The question of how to address optimal power capture, especially when the system dynamics are nonlinear and the actuators are subject to unknown faults, is significant. This paper studies the control methodology for variable-speed variable-pitch wind turbines including the effects of uncertain nonlinear dynamics, system fault uncertainties, and unknown external disturbances. The nonlinear model of the wind turbine is presented, and the problem of maximizing extracted energy is formulated by designing the optimal desired states. With the known system, a model-based nonlinear controller is designed; then, to handle uncertainties, the unknown nonlinearities of the wind turbine are estimated by utilizing radial basis function neural networks. The adaptive neural fault tolerant control is designed passively to be robust on model uncertainties, disturbances including wind speed and model noises, and completely unknown actuator faults including generator torque and pitch actuator torque. The Lyapunov direct method is employed to prove that the closed-loop system is uniformly bounded. Simulation studies are performed to verify the effectiveness of the proposed method.

关键词: wind turbine nonlinear model     maximum power tracking     passive fault tolerant control     adaptive neural control    

新型双馈变速凸极同步电机

宁玉泉

《中国工程科学》 2004年 第6卷 第12期   页码 27-31

摘要:

提出一种新型双馈变速凸极同步电机,阐述了它的基本原理和结构,电机的转子采用分裂磁极和正交绕组, 结构简单、可靠。转子绕组由低频交流变频电源供电,使电机具有变速恒频的特性。通过原型样机的试验,验证了该项发明的正确性和实用性,它将在大型水电、风电中得到广泛应用。

关键词: 凸极同步电机 变速恒频 交流励磁 双馈    

Induction motors variable speed drives diagnosis through rotor resistance monitoring

K. YAHIA, S. ZOUZOU, F. BENCHABANE

《能源前沿(英文)》 2012年 第6卷 第4期   页码 420-426 doi: 10.1007/s11708-012-0192-z

摘要: Induction motor driven by vector control method makes high performance control of torque and speed possible. The decoupling of flux and electromagnetic torque obtained by field orientation depends on the precision and the accuracy of the estimated states. Rotor asymmetries lead to perturbations of air gap flux patterns in induction machines. These perturbations in flux components affect the electromagnetic torque, as well as stator currents and voltages. This paper first investigates the control of the induction motor using an extended Kalman filter (EKF) for a direct field-oriented control. It then studies the broken rotor bars (BRBs) fault by the monitoring the rotor resistance. The hypothesis on which the detection is based is that the apparent rotor resistance of the motor will increase when a rotor bar breaks. The rotor resistance is estimated and compared with its nominal value to detect BRBs fault. The EKF estimates the rotor flux, speed and rotor resistance on line by using only measurements of the stator voltages and currents. Simulation results show the effectiveness of the proposed method in the cases of load torque perturbation and speed reversion.

关键词: induction motor     vector control     broken rotor bars (BRBs) diagnostic     extended Kalman filter (EKF)    

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

《能源前沿(英文)》 2012年 第6卷 第2期   页码 184-192 doi: 10.1007/s11708-012-0185-y

摘要: Frequency regulation in a generation mix having large wind power penetration is a critical issue, as wind units isolate from the grid during disturbances with advanced power electronics controllers and reduce equivalent system inertia. Thus, it is important that wind turbines also contribute to system frequency control. This paper examines the dynamic contribution of doubly fed induction generator (DFIG)-based wind turbine in system frequency regulation. The modified inertial support scheme is proposed which helps the DFIG to provide the short term transient active power support to the grid during transients and arrests the fall in frequency. The frequency deviation is considered by the controller to provide the inertial control. An additional reference power output is used which helps the DFIG to release kinetic energy stored in rotating masses of the turbine. The optimal speed control parameters have been used for the DFIG to increases its participation in frequency control. The simulations carried out in a two-area interconnected power system demonstrate the contribution of the DFIG in load frequency control.

关键词: doubly fed induction generator (DFIG)     load frequency control     inertial control     wind energy conversion system (WECS)    

Performance of PI controller for control of active and reactive power in DFIG operating in a grid-connected variablespeed wind energy conversion system

Azzouz TAMAARAT,Abdelhamid BENAKCHA

《能源前沿(英文)》 2014年 第8卷 第3期   页码 371-378 doi: 10.1007/s11708-014-0318-6

摘要: Due to several factors, wind energy becomes an essential type of electricity generation. The share of this type of energy in the network is becoming increasingly important. The objective of this work is to present the modeling and control strategy of a grid connected wind power generation scheme using a doubly fed induction generator (DFIG) driven by the rotor. This paper is to present the complete modeling and simulation of a wind turbine driven DFIG in the second mode of operating (the wind turbine pitch control is deactivated). It will introduce the vector control, which makes it possible to control independently the active and reactive power exchanged between the stator of the generator and the grid, based on vector control concept (with stator flux or voltage orientation) with classical PI controllers. Various simulation tests are conducted to observe the system behavior and evaluate the performance of the control for some optimization criteria (energy efficiency and the robustness of the control). It is also interesting to play on the quality of electric power by controlling the reactive power exchanged with the grid, which will facilitate making a local correction of power factor.

关键词: wind power     doubly fed induction generator (DFIG)     vector control     active power     reactive power     maximum power point tracking (MPPT)    

Evaluation of measurement uncertainty of the high-speed variable-slit system based on the Monte Carlo

Yin ZHANG, Jianwei WU, Kunpeng XING, Zhongpu WEN, Jiubin TAN

《机械工程前沿(英文)》 2020年 第15卷 第4期   页码 517-537 doi: 10.1007/s11465-020-0589-z

摘要: This paper presents a dynamic and static error transfer model and uncertainty evaluation method for a high-speed variable-slit system based on a two-dimensional orthogonal double-layer air-floating guide rail structure. The motion accuracy of the scanning blade is affected by both the moving component it is attached to and the moving component of the following blade during high-speed motion. First, an error transfer model of the high-speed variable-slit system is established, and the influence coefficients are calculated for each source of error associated with the accuracy of the blade motion. Then, the maximum range of each error source is determined by simulation and experiment. Finally, the uncertainty of the blade displacement measurement is evaluated using the Monte Carlo method. The proposed model can evaluate the performance of the complex mechanical system and be used to guide the design.

关键词: air-floating guide rail     error transfer model     driving and following structure     dynamic error     uncertainty evaluation     Monte Carlo method    

DFIG sliding mode control fed by back-to-back PWM converter with DC-link voltage control for variablespeed wind turbine

Youcef BEKAKRA,Djilani BEN ATTOUS

《能源前沿(英文)》 2014年 第8卷 第3期   页码 345-354 doi: 10.1007/s11708-014-0330-x

摘要: This paper proposes an indirect power control of doubly fed induction generator (DFIG) with the rotor connected to the electric grid through a back-to-back pulse width modulation (PWM) converter for variable speed wind power generation. Appropriate state space model of the DFIG is deduced. An original control strategy based on a variable structure control theory, also called sliding mode control, is applied to achieve the control of the active and reactive power exchanged between the stator of the DFIG and the grid. A proportional-integral-(PI) controller is used to keep the DC-link voltage constant for a back-to-back PWM converter. Simulations are conducted for validation of the digital controller operation using Matlab/Simulink software.

关键词: doubly fed induction generator (DFIG)     wind turbine     back-to-back pulse width modulation (PWM)     DC-link voltage     sliding mode control    

一种新颖的用于宽输入电压范围的LLC谐振变换器的变模态控制策略 Article

Hui-pin LIN,Xiao-guang JIN,Liang XIE,Jin HU,Zheng-yu LU

《信息与电子工程前沿(英文)》 2017年 第18卷 第3期   页码 410-422 doi: 10.1631/FITEE.1600029

摘要: 本文提出了一种新颖的适用于LLC谐振变换器的混合模态控制策略,可以使得LLC谐振变换器输入宽电压范围。这种控制策略结合了全桥LLC谐振变换器,半桥LLC谐振变换器,变频控制和变脉宽控制的优点。在这种控制策略下,不同的输入电压决定了不同的电路工作模态。当输入电压很低的时候,电路采用了全桥电路和变频控制(FB_VF模态)。当输入电压升高到一定值,电路切换到全桥电路和移相控制(FB_PS模态)。当输入电压进一步上升时,电路切换到半桥电路和变频控制(FB_VF模态)。这种电路模态的切换是由数字信号处理器(digital signal processor, DSP)来实现的,不需要外加辅助电路,只需要修改一下软件。从轻载到重载下,LLC谐振变换器的原边MOSFET可以实现零电压开通(zero-voltage switching, ZVS),副边二极管可以实现零电流关断(zero-current switching, ZCS)。本文用一个额定功率300 W,输出电压450 V的LLC,输入电压20 V到120 V的谐振变换器的样机验证了这个优化的控制策略。实验结果显示,在这种控制策略下,变换器的最大工作效率可以达到95.7%,并且输入电压范围扩大了3倍。

关键词: 串并联谐振变换器;全桥;半桥;变频;移相;宽范围输入电压    

变频驱动并联水泵变压变流量运行优化调度

李洪斌,张承慧,宋军

《中国工程科学》 2001年 第3卷 第9期   页码 52-57

摘要:

分析了变频驱动并联水泵变压变流量运行优化调度问题的常用建模方法,并比较了各种方法的优劣。 常用的方法是以水泵轴功率作为目标函数,以供水指标和高效区为约束条件。另一种方法是以满足扬程指标时 的实际流量与所需流量之差的二次方作为目标函数,以水泵的高效区作为约束条件。提出了一种新的建模方法, 模型物理意义与实际工况严格相符,具有较高的精度,满足了工程中对水泵切换频率尽量小的要求。仿真结果 表明该方法是有效的。

关键词: 优化调度     有约束非线性规划     水泵调速    

用遗传算法求解供水泵站的效率优化问题

廖莉,林家恒,张承慧

《中国工程科学》 2002年 第4卷 第9期   页码 54-58

摘要:

供水企业向来是城市的用电大户,其用电量主要体现在泵站水泵机组的电耗上。供水泵站的高效运行对节约电能、安全供水具有极为重要的意义。文章对供水泵站的效率优化问题进行了探讨,在提出用指数曲线准确地拟合水泵性能曲线的基础上,建立了供水栗站效率优化问题的数学模型,并设计了相应的遗传算法进行求解,仿真实验结果表明了该算法合理、有效。

关键词: 供水泵站     数值拟合     优化     遗传算法    

风力发电变流器发展现状与展望

马伟明,肖飞

《中国工程科学》 2011年 第13卷 第1期   页码 11-20

摘要:

风电机组宽泛的使用环境,使作为机组关键设备之一的大容量变流器必须满足高功率密度、高可靠性与优良控制性能等要求。国产风电变流器的研发近几年有了较快的发展,但总体上依然落后于国外先进水平。文章对风电变流器,重点是直驱式全功率变流器的若干关键技术做了介绍,给出了相关问题的解决思路。

关键词: 风力发电     变速恒频     双馈型     直驱型     变流器    

Approximation of structural damping and input excitation force

Mohammad SALAVATI

《结构与土木工程前沿(英文)》 2017年 第11卷 第2期   页码 244-254 doi: 10.1007/s11709-016-0371-9

摘要: Structural dynamic characteristics are the most significant parameters that play a decisive role in structural damage assessment. The more sensitive parameter to the damage is the damping behavior of the structure. The complexity of structural damping mechanisms has made this parameter to be one of the ongoing research topics. Despite all the difficulties in the modeling of damping, there are some approaches like as linear and nonlinear models which are described as the energy dissipation throughout viscous, material or structural hysteretic and frictional damping mechanisms. In the presence of a mathematical model of the damping mechanisms, it is possible to estimate the damping ratio from the theoretical comparison of the damped and un-damped systems. On the other hand, solving the inverse problem of the input force estimation and its distribution to each SDOFs, from the measured structural responses plays an important role in structural identification process. In this paper model-based damping approximation method and a model-less structural input estimation are considered. The effectiveness of proposed methods has been carried out through analytical and numerical simulation of the lumped mass system and the results are compared with reference data. Consequently, high convergence of the comparison results illustrates the satisfactory of proposed approximation methods.

关键词: structural modal parameters     damping identification method     input excitation force identification     Inverse problem    

Tacholess order-tracking approach for wind turbine gearbox fault detection

Yi WANG, Yong XIE, Guanghua XU, Sicong ZHANG, Chenggang HOU

《机械工程前沿(英文)》 2017年 第12卷 第3期   页码 427-439 doi: 10.1007/s11465-017-0452-z

摘要:

Monitoring of wind turbines under variable-speed operating conditions has become an important issue in recent years. The gearbox of a wind turbine is the most important transmission unit; it generally exhibits complex vibration signatures due to random variations in operating conditions. Spectral analysis is one of the main approaches in vibration signal processing. However, spectral analysis is based on a stationary assumption and thus inapplicable to the fault diagnosis of wind turbines under variable-speed operating conditions. This constraint limits the application of spectral analysis to wind turbine diagnosis in industrial applications. Although order-tracking methods have been proposed for wind turbine fault detection in recent years, current methods are only applicable to cases in which the instantaneous shaft phase is available. For wind turbines with limited structural spaces, collecting phase signals with tachometers or encoders is difficult. In this study, a tacholess order-tracking method for wind turbines is proposed to overcome the limitations of traditional techniques. The proposed method extracts the instantaneous phase from the vibration signal, resamples the signal at equiangular increments, and calculates the order spectrum for wind turbine fault identification. The effectiveness of the proposed method is experimentally validated with the vibration signals of wind turbines.

关键词: wind turbine     variable-speed operating conditions     Vold-Kalman filtering     tacholess order tracking    

大功率交流电机变频调速技术的研究

李崇坚

《中国工程科学》 2009年 第11卷 第5期   页码 31-36

摘要:

论述了我国大功率交交(AC-AC)变频调速技术的研究和国产化装备的研制工程,丰富并完善了大功率交流调速理论,形成了自主创新的核心技术,解决了大功率交流调速装备的多项关键技术,推动国产交流调速装备步入国际先进行列,立足工程,取得显著的经济效益和社会效益;并介绍了我国第一套7.5 MVA三电平IGCT交直交(AC-DC-AC)变频调速系统的研制,该变频器结构紧凑、性能良好、运行可靠,达到国际先进水平。

关键词: 大功率交流电机     交流调速     交交变频     交直交变频    

标题 作者 时间 类型 操作

On the improvement design of dynamic characteristics for the roller follower of a variable-speed plate

Hui Ching FAN, Hong Sen YAN

期刊论文

Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault

Hamed HABIBI, Hamed RAHIMI NOHOOJI, Ian HOWARD

期刊论文

新型双馈变速凸极同步电机

宁玉泉

期刊论文

Induction motors variable speed drives diagnosis through rotor resistance monitoring

K. YAHIA, S. ZOUZOU, F. BENCHABANE

期刊论文

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

期刊论文

Performance of PI controller for control of active and reactive power in DFIG operating in a grid-connected variablespeed wind energy conversion system

Azzouz TAMAARAT,Abdelhamid BENAKCHA

期刊论文

Evaluation of measurement uncertainty of the high-speed variable-slit system based on the Monte Carlo

Yin ZHANG, Jianwei WU, Kunpeng XING, Zhongpu WEN, Jiubin TAN

期刊论文

DFIG sliding mode control fed by back-to-back PWM converter with DC-link voltage control for variablespeed wind turbine

Youcef BEKAKRA,Djilani BEN ATTOUS

期刊论文

一种新颖的用于宽输入电压范围的LLC谐振变换器的变模态控制策略

Hui-pin LIN,Xiao-guang JIN,Liang XIE,Jin HU,Zheng-yu LU

期刊论文

变频驱动并联水泵变压变流量运行优化调度

李洪斌,张承慧,宋军

期刊论文

用遗传算法求解供水泵站的效率优化问题

廖莉,林家恒,张承慧

期刊论文

风力发电变流器发展现状与展望

马伟明,肖飞

期刊论文

Approximation of structural damping and input excitation force

Mohammad SALAVATI

期刊论文

Tacholess order-tracking approach for wind turbine gearbox fault detection

Yi WANG, Yong XIE, Guanghua XU, Sicong ZHANG, Chenggang HOU

期刊论文

大功率交流电机变频调速技术的研究

李崇坚

期刊论文