Stabilization of power system with TCSDR based on VSS theory

In order to control a large complex power system, a more flexible decentralized control scheme is desired. Since the system configuration is changing continuously, the system must be controlled based on uncertain and inadequate information. The control scheme should provide robustness. The sliding mode control based on variable structure system theory is regarded as a promising robust control scheme. In this control, the structure of the control system is changed across the hyperplane (switching plane) in state space so that the state variables of the system are kept on the hyperplane. In this paper, applications of sliding mode control to power system stabilization are discussed. The sliding mode control is applied to the control of the thyristor‐controlled SDR (System Damping Resistor). Since the SDR is operated discretely (on or off), it is impossible to keep the state variables on the switching plane all the time. Therefore, “partial” sliding mode control is introduced. A new practical switching plane for sliding mode control is developed. Using the plane, the system can be stabilized effectively. © 2001 Scripta Technica, Electr Eng Jpn, 135(2): 33–42, 2001     

直流微电网自适应滑模控制策略

为提高微电网的稳定性,提出一种集自适应观测技术、滑模控制方法、定频PWM技术于一体的新型定频PWM自适应滑模控制策略,可在不需要增加额外传感器/硬件电路的情况下实现对状态变量的快速跟踪和调节,便于直流微电网内微电源和负荷的扩展与即插即用,且简化了滤波器的设计难度。同时,采用非线性复合控制方法在恒功率负载突变的情况下实现对母线电压和系统稳定控制的目标。初始状态的合理选择、变切换面的设计,使得状态变量全程处于滑动模态,并且抖振现象得以减轻。在包含光伏电源、燃料电池、蓄电池、双向Buck/Boost变换器、恒功率负载与阻性负载的直流微电网仿真环境中,验证了所提控制方法的有效性。     

基于滑模控制的牵引变流器网侧有源滤波器电流控制策略

针对有源滤波器电流跟踪控制模块中现在控制方法灵活性较差、控制精度较低的不足,基于滑模变结构原理,对应用于牵引变流器网侧有源滤波器中的电流跟踪控制策略进行了研究。首先根据滑模控制原理从滑模切换面函数及控制函数两方面对控制策略进行了设计;在此基础上根据可达性条件从限制抖振幅度的角度对控制函数进行了优化;最后针对动车组不同运行工况,对所提控制策略在网侧有源滤波器中的控制效果进行了仿真验证。仿真结果表明,所提电流控制策略具有较好的网侧谐波补偿和抑制效果以及较高的电流跟踪控制精度,达到了预期的目标。     

多区域互联电力系统的PI滑模负荷频率控制

提出了一种用于多区域互联电力系统的负荷频率综合PI滑模控制方法,该方法同时发挥了基于新区域控制偏差的比例积分控制和滑模控制的优点,选用带积分的滑模超面方程使系统从一开始就进入滑模状态,当系统进入滑模状态后,转化为基于新区域控制偏差的比例积分控制。在考虑发电机变化率约束和具体控有控制死区条件下,所提出的综合控制方法仍能使系统取得较好的性能,而且克服各自单一控制的不足,仿真结果显示该方法是简单的、有效的、并且能够保证整个系统是渐进稳定的。     

DESIGN OF VARIABLE STRUCTURE CONTROLLER FOR STATIC VAR COMPENSATOR

ABSTRACT

Static Var Compensator (SVC) is a relatively new kind of reactive power and voltage control device. It can be used not only to improve dynamic and transient stability of power system, but is especially suitable for voltage control of long distance bulk power transmission lines. To enhance the performance of SVC, in addition to voltage control (main control), a supplementary control (auxiliary control) is required. Variable Structure (VS) Stabilizer is proposed in this paper, as supplementary controller to SVC. The machine, excitation and SVC dynamics are considered. In this paper, a systematic procedure for evaluating gains for sliding mode to occur is presented. The switching vector is constructed using pole-assignment method. Trial and error, and heuristics approach is completely avoided for evaluating the gains in the sliding mode     

Power system damping enhancement using unified power flow controller (UPFC)

The Unified Power Flow Controller (UPFC) can inject voltage with controllable magnitude and phase angle in series with a transmission line. It can also generate or absorb controllable reactive power. UPFC is expected to be able to damp power system oscillations more effectively than power electronics devices such as SVG and TCSC. In this paper, a control system design of a UPFC for power system damping enhancement based on the eigenvalue control method is proposed. It is made clear that the best design method for the power system damping enhancement is to determine steady‐state values of the UPFC control variables and the control parameters of the UPFC such as gains and time constants simultaneously, because the controllability of UPFC depends on the steady‐state values of UPFC and the power flow condition. The effectiveness of the proposed control system taking into account UPFC inverter ratings is verified by digital time simulation. Furthermore the effects of the input signals to the UPFC controller on small‐signal stability and transient stability enhancement are studied, and it is made clear that UPFC controllers using global information are more effective for power system damping enhancement than those using local information because global information has stronger observability for power system oscillations than local information. © 2000 Scripta Technica, Electr Eng Jpn, 133(3): 35–47, 2000     

Sliding mode control of singularly perturbed Markovian jump delayed systems with nonlinearity

This paper is concerned with sliding mode control (SMC) of a class of time‐delay nonlinear singularly perturbed Markovian jump systems. Firstly, a switching surface function is designed, and a delay‐dependent condition is derived in terms of ?‐independent linear matrix inequality, which guarantees that the resulting sliding mode dynamics is mean‐square exponentially stable. Then an algorithm is given to estimate the stability bound. Moreover, an adaptive SMC law is synthesized to drive the system trajectories onto the designed switching surface in a finite time. Finally, a numerical example is presented to show the effectiveness of proposed method. Copyright © 2012 John Wiley & Sons, Ltd.     

Adaptive nonsingular terminal sliding mode control of MEMS gyroscope based on backstepping design

An adaptive nonsingular terminal sliding mode (NTSM) tracking control scheme based on backstepping design is presented for micro‐electro‐mechanical systems (MEMS) vibratory gyroscopes in this paper. The NTSM controller is designed based on backstepping strategy to eliminate the singularity, while ensuring the control system to reach the sliding surface and converge to equilibrium point in a finite period of time from any initial state. In addition, the proposed approach develops an online identifier scheme, which can real‐time estimate the angular velocity and the damping and stiffness coefficients. All adaptive laws in the control system are derived in the same Lyapunov framework, which can guarantee the globally asymptotical stability of the closed‐loop system. Numerical simulations for a MEMS gyroscope are investigated to demonstrate the validity of the proposed control approaches. Copyright © 2014 John Wiley & Sons, Ltd.     

直驱型波浪发电系统的混沌运动及反步滑模变控制

为研究直驱式波浪发电系统的混沌现象及混沌控制问题,根据直线电机双轴数学模型,将系统转化为类Lorenz混沌方程。通过数值法计算最大Lyapunov指数谱,证明在特定参数和工况下,电机系统会出现混沌运动。通过构造状态反馈解耦,降低混沌系统阶数。采用反步法构造虚拟控制量,针对虚拟控制量设计滑模控制器,构造控制律进行混沌控制,提出反步滑模变控制方案。稳定性分析中,根据Lyapunov稳定性理论,证明了系统的全局一致渐进收敛。仿真结果表明,所设计反步滑模变控制器能使直线电机系统迅速脱离混沌状态,在抑制传统滑模控制中抖振现象的同时,保留了滑模变结构的强鲁棒性,具有一定的优越性。     

滑模变结构控制在有源电网调节系统中的应用

研究有源电网调节系统的滑模变结构控制。在分析系统数学模型与控制目标基础上，提出切换函数和推出滑模控制算法，该算法简单且易于实现，最后给出的仿真结果证实了该滑模控制的有效性。     

永磁同步电动机的有限时间跟踪控制

针对永磁同步电动机绕组相电流和转速强耦合特性,基于永磁同步电动机精确的数学模型,依据中继切换控制机制和有限时间收敛的终端滑动模态控制机制,研究了永磁同步电动机的有限时间跟踪问题,给出了其终端滑模控制器的设计方案。在所设计的控制作用下,闭环系统将在有限时间内达到平衡状态,保证了闭环系统所有信号的有界性和平衡点的全局稳定性,系统在有限时间内精确地跟踪给定的参考信号。对永磁同步电动机模型进行了数值仿真,结果表明,在所设计的终端滑模控制器作用下,系统的跟踪误差在有限时间内达到零,验证了所提算法的正确和有效性。     

自适应滑模控制具有状态和输入时滞的不确定系统

针对一类对象模型具有非匹配不确定性,且同时具有状态时滞和输入时滞的线性系统,基于LMI方法,提出了系统存在滑动模态时滞相关的充分条件,考虑到在处理输入时滞时引入了未知扰动,进一步设计了对扰动参数具有自适应估计能力自适应滑模控制器,该方法保证了闭环系统鲁棒渐近稳定。仿真结果进一步证实了该控制策略的可行性。     

含扩展状态观测器的双馈风机事件触发滑模控制（撤销发表）

提出一种基于事件触发滑模控制(SMC)的双馈风机(DFIG)直接功率控制方法。传统的控制方法需要控制信号执行元件不断更新由计算单元传输的控制信号,而这种控制信号执行方式较为冗余且需要额外的通信和执行成本。事件触发控制原理能够决策所执行控制信号的最佳更新时间节点,并在保证控制效果的同时减少计算单元与执行单元之间的通信。将事件触发控制的原理与SMC结合起来,并用于DFIG的直接功率控制中。同时,设计了一种让系统具有主动抗干扰能力的扩展状态观测器。采用Lyapunov函数法验证了该控制系统的渐近稳定性。最后通过试验算例,验证了所提方法的有效性。     

基于模糊滑模观测器的永磁同步电机进给系统速度估计

为解决目前伺服系统中采用机械位置传感器所存在的诸多缺点,提出一种用于永磁同步电机(PMSM)进给系统的模糊滑模速度观测器,实现无速度传感器控制。针对传统滑模观测器的抖振问题,采用Sigmoid函数代替传统理想开关函数,并引用模糊控制器自适应调整滑模增益以减小抖振,实现软切换连续控制。估计反电动势可以直接由控制函数的输出获得,省略了传统观测器中的低通滤波器和相角补偿。利用李亚普诺夫函数证明了设计的滑模观测器的渐进稳定性。仿真结果表明:设计的模糊滑模观测器能够对PMSM转子速度进行精确辨识,并有良好的动、稳态性能。     

基于逆推滑模的混合传动型风力机并网控制方法

带有差动调速机构的混合传动型风力机可在无需电力电子变频装置的条件下,采用同步发电机实现风电的友好并网消纳。为了进一步提高该新型机组的并网运行性能,结合逆推设计方法与滑模控制理论,提出了一种适用于混合传动型风力机发电单元的逆推滑模励磁控制方法。将扩张状态观测器与所提逆推滑模控制算法相结合,很好地补偿了控制系统中模型参数的不确定性及风轮/电网端扰动的影响;构建了李亚普诺夫判据,证明了控制系统的全局渐近稳定性。搭建了1.5 MW混合传动型风力机的仿真模型及半物理试验平台,并对所提控制方法的控制效果进行了对比验证研究。结果表明,在不同的风速条件及电网故障下,所提逆推滑模励磁控制方法可更好地提升混合传动型风力机的并网运行性能。     

PWM-quasi-sliding mode control for APFC converters

This paper presents the design and analysis of a PWM-quasi-sliding mode controller for active power factor correction (APFC) converters from a theoretical perspective. A novel design method, which contains the external ramp signal information in switching function, can be used to design a sliding mode controller with a constant switching frequency without any slope matching issues. The rigorous conclusions for reaching conditions and system stability conditions are given according to the PWM-quasi-sliding mode control theory. Three different approaches, namely conventional sliding mode control, triangular sliding mode control and PWM-quasi-sliding mode control, are compared in this paper. The simulation results show that the performance of PWM-quasi-sliding mode control agrees with the theoretical design, and this mode shows better working characteristic than conventional sliding mode control and triangular sliding mode control.     

Sliding mode control of switched hybrid systems with time‐varying delay

This paper is concerned with the sliding mode control of a continuous‐time switched system with time‐varying delay in its state. By using the average dwell time approach and the piecewise Lyapunov function technique, a sufficient condition is first proposed to guarantee the exponential stability of the unforced system with the decay estimate explicitly given. A sufficient condition of the existence of a reduced‐order sliding mode dynamics is derived, and an explicit parametrization of the desired sliding surface is also given. The obtained conditions will be solved using the cone complementary linearization (CCL) method. An adaptive sliding mode controller for the reaching motion is then designed such that the trajectories of the resulting closed‐loop system can be driven onto a prescribed sliding surface and maintained there for all subsequent times. All the conditions obtained in this paper are delay dependent. Finally, two numerical examples are given to illustrate the effectiveness of the proposed theory. Copyright © 2008 John Wiley & Sons, Ltd.     

一种永磁同步电机无模型超螺旋快速终端滑模控制方法

针对内置式永磁同步电机(interior permanent magnet synchronous motor, IPMSM)由于内部参数变化、外部扰动等各种不确定性因素导致控制性能不佳的问题,提出一种无模型超螺旋快速终端滑模控制方法。首先,建立考虑IPMSM不确定性的新型超局部模型,结合超螺旋算法和快速终端切换函数设计无模型超螺旋快速终端滑模控制器,确保系统状态有限时间收敛,并有效减小抖振。其次,设计扩展滑模扰动观测器精准估计超局部模型中的未知部分,并前馈补偿给设计的控制器,进一步提升系统的抗干扰能力和跟踪性能。最后,通过与PI控制和传统无模型滑模控制进行仿真实验对比,验证了该方法具有更快的收敛速度和更强的鲁棒性。     

坦克炮控伺服系统的模糊滑模变结构控制

针对坦克炮控伺服系统这一类非线性和不确定性的复杂控制对象,提出一种模糊滑模控制方法.该方法将滑模控制与模糊逻辑相结合,采用滑模开关函数作为输入组成模糊逻辑推理器,它的输出用以在线调整模糊控制器的输出增益,解决了直线伺服系统跟踪性能和鲁棒性能之间的矛盾.从理论上证明了滑动平面的稳定性,并且通过仿真验证了该结果.仿真结果表明该设计方法大大优于经典设计,为炮控伺服系统实际设计提供了一种可行的新方法.     

Adaptive TS‐FNN control for a class of uncertain multi‐time‐delay systems: The exponentially stable sliding mode‐based approach

This paper presents an adaptive Takagi–Sugeno fuzzy neural network (TS‐FNN) control for a class of multiple time‐delay uncertain nonlinear systems. First, we develop a sliding surface guaranteed to achieve exponential stability while considering mismatched uncertainty and unknown delays. This exponential stability result based on a novel Lyapunov–Krasovskii method is an improvement when compared with traditional schemes where only asymptotic stability is achieved. The stability analysis is transformed into a linear matrix inequalities problem independent of time delays. Then, a sliding mode control‐based TS‐FNN control scheme is proposed to achieve asymptotic stability for the controlled system. Since the TS‐FNN combines TS fuzzy rules and a neural network structure, fewer numbers of fuzzy rules and tuning parameters are used compared with the traditional pure TS fuzzy approach. Moreover, all the fuzzy membership functions are tuned on‐line even in the presence of input uncertainty. Finally, simulation results show the control performance of the proposed scheme. Copyright © 2008 John Wiley & Sons, Ltd.