基于多目标排序的无刷双馈电机预测控制

首先推导无刷双馈电机(BDFM)在统一坐标系下的电压模型和转矩模型,在此基础上给出电机转矩和控制电机定子磁链的预测方程,随后给出基于多目标排序的预测控制系统设计方法,通过对转矩和磁链的预测误差进行综合排序来选择基本电压矢量,实现对电机转矩和控制电机定子磁链的直接控制。仿真实验结果证明,该方法可有效减小转矩脉动、改善电流谐波,具有良好的动、静态性能。     

水轮机水门的分数阶PID控制策略研究

针对水轮机调速系统的强非线性及易受各种内外部干扰影响,基于分数阶PID控制策略提出了一种新型的水门非线性控制器。通过对水轮机水门开度模型进行反馈线性化,结合分数阶PID控制理论约束自定义的控制变量,且利用遗传算法在线调节控制器的参数。仿真结果证明,与常规PID控制方式相比,所设计的水门分数阶PID控制器能有效地阻尼系统振荡,调速系统的鲁棒性得到较好的改善。     

无刷双馈电机MATLAB建模与矢量控制仿真研究

本文首先对无刷双馈电机(BDFM)的结构进行分析,然后在转子速模型的基础上推导出BDFM的数学模型,并通过Matlab/Simulink建立仿真模型;提出一种新的矢量控制方法实现对BDFM的控制,通过仿真对此控制方法进行验证。此控制方法能实现BDFM的宽范围调速,具有较好的静动态特性。     

模块化多电平变换器的非线性控制

针对模块化多电平变换器(modular multilevel converter,MMC)多变量、非线性、强耦合的特点,提出了一种基于反馈线性化理论的滑模变结构控制策略。首先,建立MMC的非线性状态函数模型,利用输出重定义的反馈线性化理论,将其转化为线性模型,实现解耦控制。在解耦后的线性模型基础上,设计滑模变结构控制器。仿真结果证明,该文的控制策略具有良好的动态调节特性和稳态特性,且对系统参数偏差具有鲁棒性。     

双馈风电系统混沌运动分析及解耦自适应反步法控制

为研究双馈风电系统的混沌现象及其控制问题,根据电机d-q轴数学模型,导出非线性微分方程。采用Wolf算法计算其最大Lyapunov指数谱,证明电机在某些工作条件及参数下会出现混沌运动。采用磁场定向矢量控制技术,构造状态反馈解耦,降低混沌系统阶数。基于解耦模型,采用反步法设计混沌控制器。针对含有未知参数或状态的系统,提出自适应反步法,构造虚拟控制量,设计反步控制律,实时跟踪预测系统参数并实现混沌控制。通过构造Lyapunov方程,分析混沌控制系统的稳定性,保证系统状态能快速稳定收敛至给定值。控制系统不同运行工况仿真结果表明,解耦自适应反步法可使双馈电机快速脱离混沌状态,响应速度快、控制精度高,鲁棒性强。     

无刷双馈风力发电机的自抗扰解耦控制

针对无刷双馈电机(BDFM)结构的复杂性、随环境的可改变性及传统的PID控制在BDFM中应用不理想等,提出了一种新型基于扩张观测器的非线性PID控制——自抗扰控制方法来实现对风力发电系统有功功率和无功功率的解耦控制。仿真结果证明了该方法的正确性和有效性,具有更强的鲁棒性和可实现性。     

基于输入输出反馈精确线性化的三相APF控制

将输入输出反馈精确线性化控制方法应用于三相有源电力滤波器非线性控制中。首先建立三相有源电力滤波器的仿射非线性系统模型,推导出了其输入输出反馈精确线性化非线性反馈控制律,实现三相并联型有源电力滤波器有功补偿电流和无功补偿电流的解耦控制器设计。最后使用Matlab进行仿真验证,仿真试验结果表明,该控制策略能较好地实现APF的解耦控制,具有较好的补偿特性,经该控制算法补偿,谐波畸变率限制在2%以下。     

考虑发电机励磁的AC/DC系统模型与控制器设计

针对高压直流输电系统(HVDC)与发电机励磁协调控制问题,建立了HVDC和发电机励磁综合控制模型,采用微分几何变换法进行部分线性化获得了与原系统相同定性行为的线性系统.基于该线性化模型设计了控制方案并对控制器进行仿真.仿真结果表明,验证了控制器的有效性、可靠性,易于实际应用.     

带恒功率负载多电平Boost变换器的复合非线性控制

针对带恒功率负载的多电平Boost变换器,提出一种将非线性干扰观测器和自适应滑模控制器相结合的复合非线性控制策略。首先应用精确反馈线性化方法将模型转化为布鲁诺夫斯基标准形式。然后在保证大信号稳定的前提下,将自适应控制方法和非线性干扰观测器加入到滑模控制器的设计中,利用李雅普诺夫理论证明整个闭环系统的稳定性。仿真和实验结果表明,与双闭环PI控制方法相比,该控制策略具有更好的动态调节性能和更强的鲁棒性。     

基于稳定逆的直流炉机组协调控制系统前馈-反馈控制

为改善协调控制系统在机组运行过程中的控制效果,提出了基于直流炉机组非线性模型的前馈-反馈控制方法:首先通过合理简化,建立具有一定精度且适用于控制器设计的非线性模型,再引入稳定逆理论,求取该模型的稳定逆解,利用逆系统前馈控制使得机组输出迅速达到设定值附近,最后设计具有多个输出变量的反馈控制器,以消除外界扰动引起的跟踪误差.在不同的静态工作点下完成状态扰动与设定值扰动的仿真实验,并与基于状态反馈线性化的非线性内模结构的控制效果进行了对比.结果表明:基于稳定逆的前馈-反馈控制具有良好的设定值跟随能力.     

A new composite adaptive speed controller for induction motor basedon feedback linearization

A new adaptive control technique is proposed to control the speed of the induction motor in this paper. First, the rotor flux is estimated with the simplified rotor flux observer on the rotor reference frame and the feedback linearization theory is used to decouple the rotor speed and the flux amplitude. Then, a new composite adaptive control algorithm based on an integral cost function is designed to control the speed of the induction motor. The overall speed control system is verified to be stable and robust to the parameter variations and external disturbances. Experimental results are provided to demonstrate the effectiveness of the presented approach. The good speed tracking and load regulating responses can be obtained by the proposed controller     

A new sliding mode position controller with adaptive load torqueestimator for an induction motor

A new sliding mode control algorithm with an adaptive load torque estimator is presented to control the position of the induction motor in this paper. First, the rotor flux is estimated with the simplified rotor flux observer in the rotor reference frame and the feedback linearization theory is used to decouple the rotor position and the rotor flux amplitude. Then, a new sliding mode position controller with an adaptive load torque estimator is designed to control the position of the induction motor such that the chattering effects associated with the classical sliding mode position controller can be eliminated. Stability analysis is carried out using the Lyapunov stability theorem. Experimental results are presented to confirm the characteristics of the proposed approach. The good position tracking and load regulating responses can be obtained by the proposed position controller     

水轮发电机组改进型非线性广义预测控制器设计

为提高水轮发电机组调速器的鲁棒性和稳定性,设计了一种基于瞬时线性化模型的水轮发电机组改进型非线性广义预测控制器(JNGPC)。为了使初始状态的建模误差最小,依据机组历史运行数据,采用遗忘因子递推增广最小二乘法辨识控制系统的初始参数。在此基础上,引入一种改进广义预测控制算法,并对控制系统在每个采样时刻进行瞬时线性化,设计了一种基于控制系统CARIMA模型瞬时线性化的改进的非线性广义预测控制器。以我国某水电站为试验对象,对水轮发电机组调节系统不同水头下开机启动进行仿真试验,并与PID、FOPID、GPC控制器进行比较。结果表明,与PID、FOPID控制器相比,所设计的JNGPC能有效抑制开机启动工况下的转速振荡,具有更强的鲁棒性和稳定性;与GPC控制器相比,JNGPC具有更高的计算效率,更符合工业现场实时性要求。     

A rotor-flux-observer-based composite adaptive speed controller foran induction motor

A composite adaptive speed controller for an induction motor based on a rotor-flux-observer is proposed in this paper. The rotor flux is estimated with the simplified rotor-flux-observer on the rotor reference frame and the input-output linearization theory is used to decouple the motor speed and the rotor flux. Then, the composite adaptive algorithm is used as the speed controller of the induction motor drive. The resulting system is verified to be stable. Some experimental results are provided to demonstrate the effectiveness of the proposed adaptive controller. Good speed tracking and load regulating responses can be obtained by the proposed composite adaptive controller. Moreover, the system can be operated in a wide range of speed and is robust to parameter variations     

无刷双馈风力发电机滑模功率解耦控制

首次采用现代控制理论中的滑模变结构方法研究了无刷双馈发电机(BDFM)运行时有功功率与无功功率的解耦控制,在状态方程的基础上,应用Lyapunov函数求得了有功功率与无功功率的滑模控制律,并在Matlab/Simu-link基础上建立了系统的仿真模型。仿真结果表明,滑模变结构控制能够有效的实现有功功率与无功功率的解耦控制,并实现了风能的最大功率捕获,证明了该控制策略的有效性。     

Simulating Feedback Linearization control of wind turbines using high‐order models

As wind turbines are becoming larger, wind turbine control must now encompass load control objectives as well as power and speed control to achieve a low cost of energy. Due to the inherent non‐linearities in a wind turbine system, the use of non‐linear model‐based controllers has the potential to increase control performance. A non‐linear feedback linearization controller with an Extended Kalman Filter is successfully used to control a FAST model of the controls advanced research turbine with active blade, tower and drive‐train dynamics in above rated wind conditions. The controller exhibits reductions in low speed shaft fatigue damage equivalent loads, power regulation and speed regulation when compared to a Gain Scheduled Proportional Integral controller, designed for speed regulation alone. The feedback linearization controller shows better rotor speed regulation than a Linear Quadratic Regulator (LQR) at close to rated wind speeds, but poorer rotor speed regulation at higher wind speeds. This is due to modeling inaccuracies and the addition of unmodeled dynamics during simulation. Similar performance between the feedback linearization controller and the LQR in reducing drive‐train fatigue damage and power regulation is observed. Improvements in control performance may be achieved through increasing the accuracy of the non‐linear model used for controller design. Copyright © 2009 John Wiley & Sons, Ltd.     

Speed and efficiency control of an induction motor withinput-output linearization

A combination of a composite adaptive speed controller and an explicit efficiency control algorithm is proposed to control the speed and power efficiency of the induction motor in this paper. First, the input-output linearization method is used to dynamically decouple the motor speed and rotor flux. Then, a composite adaptive control algorithm is designed to control the speed of the induction motor. At steady-state light-load condition, the magnetizing current command is adjusted on the basis of the product of magnetizing current command and torque current command such that the steady-state power loss is minimum. A PC-based experimental drive system has been implemented, and some experimental results are provided to demonstrate the effectiveness of the presented approach     

Sensorless scalar-controlled induction motor drives with modified flux observer

This paper presents a simple sensorless scalar control algorithm to control the speed of an induction motor. First, a modified flux observer was employed to estimate the stator flux with the voltage command and the feedback current. Then, based on the mathematical model of the induction motor, the slip frequency was calculated, and the frequency of the voltage command was compensated. An auto-boost controller was designed to overcome the decrease in voltages of the stator resistance and to maintain constant stator flux amplitude. To improve the pure integration problem, a highpass filter was installed in the stator flux observer. In this filter, the cut-off frequency is proportional to the voltage frequency; therefore, the phase shift and amplitude degradation of the estimated flux can be corrected easily. Finally, to demonstrate the proposed control algorithm, a PC-based experimental system was constructed in a 1-hp induction motor. Experimental results are presented to validate the effectiveness of our design.     

Experimental evaluation of nonlinear robust control for SMES to improve the transient stability of power systems

This paper presents a new approach and corresponding experiments for the nonlinear robust control of a superconducting magnetic energy storage (SMES) unit to improve the transient stability of power systems. Based on the result of SMES prototype experience, a new dynamic model with disturbances of SMES is adopted, and transferred to the per unit system for simplifying the dynamic analysis and controller design. Then, feedback linearization scheme and linear H/sub /spl infin// control theory are applied to design a novel SMES nonlinear robust controller in a one-machine infinite bus (OMIB) power system. In order to confirm such positive effects of the proposed control strategy, experiments are carried on a laboratory setup of SMES comparing that with a conventional proportional-integral (PI) controller. The results of the experiments demonstrate that the proposed nonlinear robust controller has more excellent performance to improve the transient stability of power systems than that of conventional PI controllers.