电力系统稳定器设计的广义相位补偿法

针对经典相位补偿法理论背景不完善、无法应用于多机系统的问题,从代数学的角度提出简单的特征值实部表达式,应用该式从新的角度分析单机无穷大系统中出现负阻尼现象的原因,解释了电力系统稳定器抑制振荡的机理.将该式推广至多机系统,导出适用于多机系统的稳定判据,该判据可以用于稳定器相位补偿参数设计和PSS选址.稳定器增益整定问题被转化为一个只包含少数变量和约束条件的多项式优化问题,介绍2种不同的方法进行求解.通过4个典型系统的算例分析,验证了该方法的可行性和正确性.

吸入式稳定器设计研究与试验

本文简要介绍吸入式稳定器的基本原理、设计方法和供油匹配方面的做法,并且扼要说明水流试验、燃烧试验以及台架试车等某些结果。从不同的用途出发,采取不同的安排,吸入式稳定器可以分别满足提高燃烧效率,扩大燃烧稳定边界和改善加力点火性能等诸方面的技术要求。

大规模电动汽车智能充电站对电力系统小干扰稳定性的影响(英文)

大规模智能充电站可以很好地满足和调节电动汽车的充电需求,但同时也不可避免地给电网的稳定性运行带来新的影响和挑战。基于阻尼转矩分析法(damping torque analysis,DTA),着重探讨智能充电站的接入对于输电网动态稳定性的影响。为了简化分析,单机无穷大系统将用于模拟配电网与外部输电网。配电网中的智能充电站群被视为一个接入输电网的等值智能充电站。分析得出,在大规模智能充电站的设计中,充电容量对于小干扰稳定性中的阻尼比有很大的影响。在其最佳充电容量下充电,将会最有利于保持系统的动态稳定,系统阻尼比也保持最大。根据所建立的Phillips-Heffron模型可知,在智能充电站的有功和无功控制通道上设计并加装稳定器,能够有效地提高系统阻尼,更快地抑制联络线上的功率振荡。算例分析验证了所得结论。

米糠与稻草的利用

米糠是稻谷辗米的重要产品,它含有大约12％的蛋白质,13—15％的脂肪,36—40％的碳水化合物。另外,还含有大量的维生素B和维生素E。粗糠至今还全是用来喂牛,尤其是奶牛和水牛良好的营养品,可增加产奶量。可是,喂多了,会产生轻泻剂的作用。如今发现,米糠是食用油的一种好原料。

Robust simultaneous tracking and stabilization of wheeled mobile robots not satisfying nonholonomic constraint

A robust unified controller was proposed for wheeled mobile robots that do not satisfy the ideal rolling without slipping constraint.Practical trajectory tracking and posture stabilization were achieved in a unified framework.The design procedure was based on the transverse function method and Lyapunov redesign technique.The Lie group was also introduced in the design.The left-invariance property of the nominal model was firstly explored with respect to the standard group operation of the Lie group SE(2).Then,a bounded transverse function was constructed,by which a corresponding smooth embedded submanifold was defined.With the aid of the group operation,a smooth control law was designed,which fulfills practical tracking/stabilization of the nominal system.An additional component was finally constructed to robustify the nominal control law with respect to the slipping disturbance by using the Lyapunov redesign technique.The design procedure can be easily extended to the robot system suffered from general unknown but bounded disturbances.Simulations were provided to demonstrate the effectiveness of the robust unified controller.

Coordinated and uncoordinated design of LFO damping controllers with IPFC and PSS using ICA and SFLA

A single machine-infinite-bus(SMIB) system including the interline power flow controllers(IPFCs) and the power system stabilizer(PSS) controller is addressed. The linearized system model is considered for investigating the interactions among IPFC and PSS controllers. To improve the stability of whole system again different disturbances, a lead-lag controller is considered to produce supplementary signal. The proposed supplementary controller is implemented to improve the damping of the power system low frequency oscillations(LFOs). Imperialist optimization algorithm(ICA) and shuffled frog leaping algorithm(SFLA) are implemented to search for optimal supplementary controllers and PSS parameters. Moreover, singular value decomposition(SVD) method is utilized to select the most effective damping control signal of IPFC lead-lag controllers. To evaluate the system performance, different operating conditions are considered. Reponses of system in five modes including uncoordinated and coordinated modes of IPFC and PSS using ICA and SFLA are studied and compared. Considering the results, response of system without controller shows the highest overshoot and the longest settling time for rotor angel at the different operating conditions. In this mode of system, rotor speed has the highest overshoot. Rotor angel in the system with only PSS includes lower overshoot and oscillation than system without controller. When PSS is only implemented, rotor speed deviation has the longest settling time. Rotor speed deviation in the uncoordinated mode of IPFC and PSS shows lower overshoot than system with only PSS and without controller. It is noticeable that in this mode, rotor angel has higher overshoot than system with only PSS. The superiority of the suggested ICA-based coordinated controllers is obvious compared with SFLA-based coordinated controllers and other system modes. Responses of coordinated PSS and IPFC SFLA-based supplementary controllers include higher peak amplitude and longer settling time compared with coordinated IPFC and PSS ICA-based controllers. This comparison shows that overshoots, undershoots and the settling times are reduced considerably in coordinated mode of IPFC based controller and PSS using ICA. Analysis of the system performance shows that the proposed method has excellent response to different faults in power system.

Chatter free sliding mode control of a chaotic coal mine power grid with small energy inputs

An augmented proportional-integral sliding surface was designed for a sliding mode controller. A chatter free sliding mode control strategy for a chaotic coal mine power grid was developed. The stability of the control strategy was proven by Lyapunov stability theorem. The proposed sliding mode control strategy eliminated the chattering phenomenon by replacing the sign function with a saturation function, and by replacing the constant coefficients in the reaching law with adaptive ones. An immune genetic algorithm was used to optimize the parameters in the improved reaching law. The cut-in time of the controllers was optimized to reduce the peak energy of their output. Simulations showed that the proposed sliding mode controller has good, chatter flee performance.

Design of an optimal active stabilizer mechanism for enhancing vehicle rolling resistance

Improving rollover and stability of the vehicles is the indispensable part of automotive research to prevent vehicle rollover and crashes.The main objective of this work is to develop active control mechanism based on fuzzy logic controller(FLC) and linear quadratic regulator(LQR) for improving vehicle path following,roll and handling performances simultaneously.3-DOF vehicle model including yaw rate,lateral velocity(lateral dynamic) and roll angle(roll dynamic) were developed.The controller produces optimal moment to increase stability and roll margin of vehicle by receiving the steering angle as an input and vehicle variables as a feedback signal.The effectiveness of proposed controller and vehicle model were evaluated during fishhook and single lane-change maneuvers.Simulation results demonstrate that in both cases(FLC and LQR controllers) by reducing roll angle,lateral acceleration and side slip angles remain under 0.6g and 4° during maneuver,which ensures vehicle stability and handling properties.Finally,the sensitivity and robustness analysis of developed controller for varying longitudinal speeds were investigated.

Robust Model Predictive Controller Design： Finite and Infinite Horizon

This paper addresses to the problem of designing, modeling and practical realization of robust model predictive control for finite and infinite prediction horizon which ensures a parameter dependent quadratic stability and guaranteed cost for linear polytopic uncertain systems. The model predictive controller design procedure based on BMI and LMI is reduced to off-line output feedback gain calculation. A numerical examples and an application to a real process is given to illustrate the effectiveness of the proposed method.

Coordinated Design of Thyristors Controlled Braking Resistors and Power System Stabilizer for Damping

This paper presents a new concept for damping electro-mechanical oscillations in large turbo generator. The proposed concept is based on coordination between Power System Stabilizer （PSS） and Thyristor Controlled Braking Resistor （TCBR）. This coordination will enhance the stability of the inertial and torsional oscillatory modes. The study is performed on system-I of the second IEEE benchmark for simulation of Sub-Synchronous Oscillations, using eigenvalue analysis and verified by detailed digital simulation. A dynamic fundamental frequency model for TCBR is developed. The pole placement technique is used to design the control system of TCBR and PSS. The shaft torque＇s following a disturbance is computed and analyzed. The obtained results indicate that substantial damping is achieved by the proposed coordination.

电源系统

Y2000-62329-469 0016066采用抽样调节器设计的灵活交流传输系统控制=FACTS control by sampled regulator design[会,英]/Wang,H.F.& Li,F.//1999 Aficon,Vol.1.—469～474(PC)介绍了抽样调节器设计法在电源系统灵活交流传输系统(FACTS)控制中的两种应用;采用静态无功伏安补偿器(SVC)的 AC 电压控制和采用统一功率流控制器(UPFC)的 DC 电压控制。并以实例电源系统予以证明。参13Y2000-62329-479 0016067采用自由振动可变结构控制器的电源系统稳定性=Stability of power system using variable structure con-troller with free chattering[会,英]/Negm,M.M.M.& Nasab,T.M.//1999 Africon,Vol.1.—479～484(PC)Y2000-62329-485 0016068无本征解方法在以灵活交流传输系统为基础的电源系统稳定器设计中的应用=Application of an eigensolu-

Renewed investigation on Power System Stabilizer design

Power System Stabilizer (PSS) was proposed during 1960s to solve the low frequency oscillation problem raised by the wide application of the high-gain fast-response exciters. The fundamentals of PSS design lie in the angle compensation to increase the damping torque, which, since then, has become an important principle in designing the various power system dampers, such as SVC, TCSC, UPFC. Although many papers have been dedicated to the application of this principle, it is interesting to note that in the real industry applications PSS parameters have to be carefully tuned on site in spite of its mature design theory. So does the classical PSS design theory really meet the PSS design demand? By combining the frequency domain and the time domain analysis, this paper reinvestigates the basic idea behind the classical PSS design theory. The paper clarifies the con-cepts of the synchronous torque as well as the damping torque and proves that the classical PSS design principles based on these concepts are not theoretically sound. Then the paper discusses the Linear Optimal Controller Design method and ana-lyzes its relations with the conventional PID design. By doing so the paper reveals the real mechanism of the PSS and proposes to use more systematic and advanced control tools to enhance the controller performance.

Finite-time stabilization of switched dynamical networks with quantized couplings via quantized controller

This paper concerns the stabilization of switched dynamical networks with logarithmic quantization couplings in a settling time.The switching sequence is constrained by hybrid dwell time. Controller is designed by using limited information. Due to the quantization and switching, traditional finite-time analysis methods cannot be utilized directly. By designing multiple Lyapunov functions and constructing comparison systems, a general criterion formulated by matrix inequalities is first given. Then specific conditions in terms of linear matrix inequalities are established by partitioning the dwell time and using convex combination technique. An optimal algorithm is proposed for the estimation of settling time. Numerical simulations are given to verify the effectiveness of the theoretical results.