一种具有预测功能的抗积分饱和PI速度控制器

在交流调速系统中,当给定大阶跃时,传统PI控制器由于积分饱和原因无法使系统在实现响应快速性的同时满足小超调甚至无超调.为解决该问题,研究了PI控制器和PD控制器,提出一种具有预测功能的抗积分饱和PI速度控制策略.该策略利用PD预测功能,根据其输出值的符号控制PI控制器的积分方向.当误差较大时,PI输出饱和,系统响应速度最快;而当误差较小时,积分器及时退出饱和,系统响应速度以负指数规律衰减至零;最终系统稳定于目标转速.实验结果表明该策略不但具有优良的动态性能,而且保留了传统PI的鲁棒性能和稳态性能.     

基于模型补偿的风力机变桨距线性自抗扰控制器设计

设计了一种变桨距线性自抗扰控制器,估计和补偿了系统未建模部分和外界干扰,实现额定风速以上时系统输出功率稳定于额定值;并采用模型补偿方法对自抗扰控制器进行优化,减少了参数整定的数目,提高了系统控制精度。对额定功率为300 kW的风电机组分别在阶跃风、阵风以及湍流风作用下进行系统仿真。结果表明,该方法可以快速调节风速变化引起的输出波动,使得系统输出稳定且超调量小,具有很好的稳定性和鲁棒性。     

机炉协调系统的非线性输出跟踪控制

为了克服非线性环节以及能量供需之间关联耦合作用对协调系统控制品质的影响，提高单元制发电机组的快速负荷响应能力，本文基于非线性稳定逆原理，采用非线性输出跟踪控制结构，针对一个通用的非线性协调系统模型，设计出非线性输出跟踪控制器。该控制器由稳定逆系统及反馈控制器两部分组成，稳定逆系统相当于前馈部分，用于提高系统的响应速度；反馈控制器保证了系统的稳定。在不同负荷下的仿真试验表明，依据非线性输出跟踪控制策略设计出的控制系统具有良好的解耦效果和设定点跟踪能力。     

永磁直线电机保证稳态精度的模糊控制

由于PD型模糊控制器缺少积分项,所以稳态的控制精度不容易得到保证。本文提出了一种保证稳态精度的模糊控制方法以提高传统模糊控制器的稳态控制精度。这种模糊系统能够选择运行一个传统的模糊控制器或者一个积分控制器,当运行积分控制器的时候,此积分控制器与一个稳态输出值的和为控制系统输出。根据不同的状态水平,在传统模糊控制器和稳态值输出之间可以进行平滑的切换。对于PMLM控制系统,当接近稳定状态的时候,保证稳态精度的模糊控制系统的输出是稳态值和变量值这两部分的和。实验结果显示这种保证稳态精度的模糊控制系统比传统的PID控制器和单个传统的模糊控制器在速度控制中可以获得更好的动态和静态性能。     

基于模糊控制器的永磁电动机矢量控制系统

采用比例积分(PI)速度控制器的永磁同步电动机矢量控制系统,在运行条件改变时,动态响应性能可能变差。为解决这一问题,可以在保留原速度控制器的基础上,利用模糊逻辑处理不确定信息的能力,对速度控制器的输出进行实时校正。仿真实验结果表明:利用该方案建立的基于模糊控制器的永磁同步电动机矢量控制系统,不但结构简单、易于实施,而且在电机参数改变或受到外部扰动的时候,仍然具有良好的动态特性和鲁棒性能。     

A design method of digital robust speed servo system considering output saturation

When a robust servo system having an integral element has a large error input, it often reveals windup phenomena caused by output saturation. It is very difficult for a strictly proper and high‐order controller to avoid having windup phenomena caused by output saturation. This paper newly proposes the digital robust speed servo system with a complete algorithm for consideration of output saturation. The proposed algorithm completely considers the output saturation of a robust speed controller connected to a PI current controller in series. Moreover, this method can be applied to both a PI speed controller and an H^∞ speed controller. The experimental results show that a robust speed servo system using the proposed algorithm has a good and stable response for a large step speed command. © 2000 Scripta Technica, Electr Eng Jpn, 132(3): 68–78, 2000     

Robust pole placement indirect adaptive control

The problem of designing a robustly stable pole placement indirect adaptive controller in the presence of output disturbances and unmodelled dynamics is addressed. The key features of such a design are the following. (1) The unknown parameters are estimated by a normalized least-squares algorithm with a dead zone to provide the stability robustness with respect to bounded disturbances and ‘small’ unmodelled dynamics. (2) The estimated model controllability is ensured by modifying the control law over a finite time. The modification involved consists of adding an internal impulse excitation and ‘freezing’ the controller parameters.     

Comparative performance analysis of teaching learning based optimization for automatic load frequency control of multi-source power systems

This paper presents a new population based parameter free optimization algorithm as teaching learning based optimization (TLBO) and its application to automatic load frequency control (ALFC) of multi-source power system having thermal, hydro and gas power plants. The proposed method is based on the effect of the influence of teacher on the output of learners and the learners can enhance their knowledge by interactions among themselves in a class. In this extensive study, the algorithm is applied in multi area and multi-source realistic power system without and with DC link between two areas in order to tune the PID controller which is used for automatic generation control (AGC). The potential and effectiveness of the proposed algorithm is compared with that of differential evolution algorithm (DE) and optimal output feedback controller tuning performance for the same power systems. The dynamic performance of proposed controller is investigated by different cost functions like integral of absolute error (IAE), integral of squared error (ISE), integral of time weighted squared error (ITSE) and integral of time multiplied absolute error (ITAE) and the robustness of the optimized controller is verified by its response toward changing in load and system parameters. It is found that the dynamic performance of the proposed controller is better than that of recently published DE optimized controller and optimal output feedback controller and also the proposed system is more robust and stable to wide changes in system loading, parameters, size and locations of step load perturbation and different cost functions.     

Reference model decomposition in direct adaptive control

This paper introduces the method of ‘reference model decomposition’ as a way to improve the robustness of model reference adaptive control systems (MRACs) with respect to unmodelled dynamics with a known structure. Such unmodelled dynamics occur when some of the nominal plant dynamics are purposely neglected in the controller design with the aim of keeping the controller order low. One of the effects of such ‘undermodelling’ of the controller is a violation of the perfect model-matching condition of the primary controller. The decomposition can be seen as a way to adjust the reference model output (and hence the control goal) to the actual model-matching capabilities. It is shown that the decomposition alleviates the negative effects unmodelled dynamics have on the error equation. Simulation examples illustrate the decomposition design steps and show the obtained improvements.     

Robust analysis and design of power system load frequency control using the Kharitonov's theorem

This paper presents a robust decentralized proportional-integral (PI) control design as a solution of the load frequency control (LFC) in a multi-area power system. In the proposed methodology, the system robustness margin and transient performance are optimized simultaneously to achieve the optimum PI controller parameters. The Kharitonov’s theorem is used to determine the robustness margin, i.e., the maximal uncertainty bounds under which the stable performance of the power system is guaranteed. The integral time square error (ITSE) is applied to quantify the transient performance of the LFC system. In order to tune the PI gains, the control objective function is optimized using the genetic algorithm (GA). To validate the effectiveness of the proposed approach, some time based simulations are performed on a three-area power system and the results are then compared with an optimal PI controller. The comparisons show that the proposed control strategy provides the satisfactory robust performance for the wide range of system parameters and load changes in the presence of system nonlinearities and is superior to the other methods.     

基于DSP和FPGA实现的逆变电源重复学习控制

研究逆变电源系统的控制方法,就是要保证逆变电源系统在任何负载下,都能输出稳定、畸变小的电压波形,尤其是在带非线性负载环境中.针对逆变电源系统,采用重复学习控制方法,并在一台DSP FPGA实现的逆变电源装置上进行实验论证.该控制方法通过跟踪误差来进行学习控制,可以有效改善逆变电源在任何负载下的输出波形.实验表明该方法具有高稳定性,快速跟踪和稳态误差小等特点.     

孤岛光伏并联逆变器系统的固定时间模糊反步控制策略

针对孤岛光伏并联逆变器系统存在固有的建模不确定性以及动态性能差的问题,提出一种固定时间模糊反步控制策略。首先,将滤波器参数和输出电流作为未知项,建立含有滤波器参数摄动和输出电流扰动的单台逆变器等效数学模型。其次,将固定时间Lyapunov稳定性原理、模糊逻辑控制理论和反步控制理论相结合,利用固定时间模糊反步控制器逼近系统中的未知项,以改善逆变器的输出电压。然后,基于严格的Lyapunov定理证明所提控制策略下的系统是固定时间稳定的,且稳定时间的上界与系统的初始状态无关。最后,通过两台20 kW样机验证了所提控制策略的有效性。     

基于数字前置滤波器优化的ZPETC在伺服跟踪控制中的应用

在高精度伺服跟踪控制系统中,为使输出响应能完整地跟踪输入指令,不仅要求输出与输入之间的相位差为零,而且要求幅值一致,通常采用零相位误差跟踪控制器(ZPETC)作为前馈控制器,补偿相位误差,但同时也产生一定的增益误差.为改善ZPETC的跟踪性能,提出一种基于L2-范数优化的前馈控制器设计方案,通过选取适当的目标函数,设计出最优的数字前置滤波器(DPF),将此滤波器与ZPETC串联构造成新的前馈控制器.仿真结果表明,采用本文提出的优化设计方案,既补偿了相位误差,又改善了系统的增益性能,从而提高了系统的跟踪精度.     

一类多变量推理控制系统的控制策略

在一种新的性能指标下,提出了多变量推理多变量控制器的设计方法,实用型多变量控制器结构避免了传递函数矩阵求逆问题。特点是算法简单,仅具有一个可调参数矩阵Q,并实现了多变量系统的动态解耦,且由于结构中滤波阵的存在,使系统稳定性大大提高。     

A robust polynomial-based control for stable processes with time delay

In this paper, the coefficient diagram method (CDM) is used to design a controller for stable processes with a time delay to achieve high performance. For this, first order plus time delay (FOPTD) and second order plus time delay (SOPTD) models are used. The explicit tuning formulae of the controller using the polynomial representation are presented based on closed-loop pole-allocation strategy according to the FOPTD and SOPTD plant models. The results are compared with other commonly available tuning methods. It is shown that the CDM control system is more successful in view of the stability, time response, disturbance rejection and robustness properties of the closed loop system.     

Bidirectional power flow control of a power converter using passive Hamiltonian techniques

A controller able to achieve bidirectional power flow for a boost‐like full‐bridge rectifier is presented. It is shown that no single output yields a stable zero dynamics for power flowing both ways. The controller is computed using port Hamiltonian passivity techniques for a suitable generalized state space averaging truncation of the system, which transforms the control objectives, namely specified output mean value of the voltage dc‐bus and unity input power factor in the ac side, into a regulation problem. Simulation and experimental results for the full system confirm the correctness of the simplifications introduced to obtain the controller. Copyright © 2007 John Wiley & Sons, Ltd.     

基于滑模变结构控制的多电平高效D类功率放大器

介绍了一种新颖的基于级联型多电平拓扑结构的开关型功率放大器，采用相移PWM技术，其开关频率是单个单元开关频率的2N倍，总的输出电压波纹很小，只需要一个较小的滤波器来抑制开关谐波。文中对多电平PWM输出信号的谐波进行分析，重点研究采用滑模电流电压双闭环控制的设计要点并推导其参数，之后研制一台2 kW级联型多电平滑模控制的电流电压双闭环D类功率放大器。试验研究结果表明：采用滑模电流电压双闭环控制的级联型多电平D类功率放大器，明显提高了系统带宽，使系统不仅对阻性负载而且对桥式整流负载都具有良好的快速性和跟踪性能，很好的瞬时响应和稳定性，较高的效率和低的输出信号谐波总畸变率值。     

为消除电力系统内低频振荡的最优模型匹配控制器

本文论证了了种新型控制器及其鲁棒性的定量计算法,以实现消除电力系统区域间的低频振荡。控制器的设计思想是适当选择一个与要求模型相匹配的品质指标,使其达极小值。从而实现同步电机的输出渐渐接近给定模型的输出。计算机仿真结果证明这种控制器是有效的。     

数字式直流传动系统的专家智能控制

基于专家智能控制思想,提出了一种结构简单、性能优越的数字式新型直流调速系统结构,该系统采用单环控制结构,对转速和电流进行专家智能控制。控制器具有强鲁棒性,在电机对象参数（如转动惯量、电磁时间常数等）大范围变化时,仍然保持良好的控制性能。实践证明,专家智能控制器效果显著,应用前景广阔。     

适用于工业园区的微电网系统能量管理

为了提高微电网系统输出特性,满足工业园区并网要求,提出一种基于功率预测、前馈控制的微电网系统能量管理策略。通过功率预测,高效控制微电网系统输出功率,跟踪厂区负荷;基于前馈控制的储能波动平抑,有效平滑系统输出,并提高电池应用效率。在RTDS实时仿真平台上,结合能量管理器,搭建微电网系统硬件在环测试平台,MW级风光储微电网系统工程的长期稳定运行验证了所提算法的有效性和稳定性。