多机系统励磁与SSSC的非线性鲁棒协调控制

针对多机电力系统中,发电机励磁和静止同步串联补偿器(static synchronous series compensator,SSSC)的协调控制问题,引入广义Hamilton系统理论,进行非线性协调控制器设计。SSSC采用考虑内部动态的三阶模型,并将SSSC与各台发电机的相互作用用附加电磁功率表示。将包含发电机励磁和SSSC的多机电力系统描述成广义耗散Hamilton系统形式,利用边界函数法和L2干扰抑制控制方法设计了发电机励磁和SSSC的协调控制器。四机两区域系统的仿真结果表明:与传统的分散控制器相比,所提的非线性协调控制器能够有效地提高系统的暂态稳定性和电压调节性能。     

双轴励磁同步发电机的微分反馈非线性最优励磁控制

本文在微分几何理论的基础上，提出了更简明、更适合工程用的面向多输入系统的微分反馈补偿物理精确线性化方法，解决了电力系统控制设计中的强非线性问题及鲁棒性问题，并据此推导了双轴励磁同步发电机的微分反馈非线性最优励磁控制规律。仿真结果表明，所设计的控制方式能较大幅度地提高系统的动态稳定性和暂态稳定性。     

CHARACTERISTICS OF AN ASYNCHRONIZED SYNCHRONOUS GENERATOR

ABSTRACT

Theoretical steady state and transient characteristics of an asynchronised synclironous ( a.s.) generator, having excitation with full compensation for the emf induced in the field windings, are presented. Also transient characteristics of an a.s. generator, having excitation with field current feedback and slip feedback, are presented taking into consideration the ceiling voltage of the exciter

Finally a novel experimental excitation scheme using cyclo-converters and field current feedback is described, using which the steady state power, reactive power versus torque angle curves of a laboratory a.s. generator are obtained for the entire range ( 0 - 180° elec) of the torque angle at synchronous speed.     

基于变速风电场控制的电力系统稳定性改善研究

以改善风电场接入的电力系统稳定性并降低稳定控制对场内机组负面影响为目标,设计基于变速风电机组的电力系统综合稳定控制器.控制器基于广域信息,应用同步机状态反馈,通过风电场衰减系统故障不平衡能量以提高同步机主系统暂态稳定性;考虑风电场与同步机关联程度的差异,     

Robust multimachine power systems control via high order sliding modes

This article presents a formal study of the transient stabilization problem, including a stability proof. A decentralized nonlinear robust control scheme for multimachine electrical power systems is presented. The mathematical model takes into account the interconnections between electrical elements of the power system such as generators, electric networks, loads and exciters. Each generator is considered as a seventh order system that includes the mechanical and rotor electrical dynamics with static exciter dynamics. The proposed control scheme is based on the Block Control methodology and Second Order Sliding Modes technique using the Super Twisting algorithm. A nonlinear observer is designed to estimate the rotor fluxes of the synchronous machines. The designed decentralized control scheme requires the only local information for each local controller. This control scheme was tested through simulation on the well known reduced 9 buses equivalent model of the WSCC system.     

IMPROVEMENT OF THE PERFORMANCE OF A SUPERCONDUCTING TURBOGENERATOR THROUGH USE OF A CONTROLLABLE REACTIVE POWER COMPENSATOR

ABSTRACT

This paper presents the dynamic performance of a superconducting turbo-generator which employes a thyristor controlled static reactive power compensator at its terminals. The application of the fast acting compensator external to the machine, in a power system, is foreseen as one possible alternative to alleviate the excitation problems which arise on account of the extremely large field time constant of a superconducting generator. This application is compatible with the fast development in the rating of static compensators and imminent use of superconducting machines in the future.

The paper dwells on the transient aspects of performance to evaluate the feasibility of use of an external controller for voltage and also incorporating stabilizing signals. Simulation of the load rejection and transient stability dynamic performance of the superconducting alternator with and without thyristor controlled static compensator brings out its superiority over the field forcing techniques usually used with the conventional generators.     

SVC与发电机励磁的非线性状态PI协调控制

针对电力系统的强非线性和不确定性,运用非线性状态比例积分（PI）解控制直接对其非线性不确定对象设计了静止无功补偿器（SVC）与发电机励磁的协调控制器。该控制器避免了基于反馈线性化理论的非线性协调控制器由于数学模型的误差而影响控制器性能的缺点,所得的控制规律与系统运行点和网络结构完全无关。仿真计算表明,SVC与发电机励磁非线性状态PI协调控制器能有效地提高系统的暂态稳定性。     

Improved synergetic excitation control for transient stability enhancement and voltage regulation of power systems

This paper proposes decentralized improved synergetic excitation controllers (ISEC) for synchronous generators to enhance transient stability and obtain satisfactory voltage regulation performance of power systems. Each generator is considered as a subsystem, for which an ISEC is designed. According to the control objectives, a manifold, which is a linear combination of the deviation of generator terminal voltage, rotor speed and active power, is chosen for the design of ISEC. Compared with the conventional synergetic excitation controller (CSEC), a parameter adaptation scheme is proposed for updating the controller parameter online in order to improve the transient stability and voltage regulation performance simultaneously under various operating conditions. Case studies are undertaken on a single-machine infinite-bus power system and a two-area four-machine power system, respectively. Simulation results show the ISEC can provide better damping and voltage regulation performance, compared with the CSEC without parameter adaptation scheme and the conventional power system stabilizer.     

同步发电机可拓励磁控制器

为了克服传统励磁控制方法的缺点,依据可拓学理论,设计了同步发电机励磁控制器.控制器以参考电压与发电机机端电压的偏差及其微分作为特征量,根据电力系统的实际情况确定特征量的经典域和可拓域,经过关联度计算、测度模式识别,确定所采用的控制策略.应用MATLAB/Simulink软件建立了基于同步发电机三阶非线性数学描述的单机无穷大电力系统仿真模型,可拓控制器用MATLAB之S函数编程实现.与常规PID励磁控制器的仿真比较结果,验证了可拓励磁控制器对于改善电力系统小扰动稳定性和大扰动稳定性的有效性.     

异步化同步发电机与同步发电机并联运行的分散变结构控制

异步化同步发电机(ASG)能提高系统的稳定性，当其与同步发电机并联运行时，联合系统的状态方程必须建立在同一坐标轴下。该文首次建立了同步坐标轴下异步化同步发电机与同步发电机并联运行时的状态方程，并对所建立的状态方程使用分散变结构控制的方法进行了励磁控制器的设计，仿真结果表明该方法有较好的动态响应，能提高系统的稳定性。     

同步发电机励磁系统对电力系统稳定的控制策略研究

介绍了PID控制器和电力系统稳定器的各个环节,通过数值计算选择合理的参数,建立了基于Matlab／Similink搭建完整的同步发电机励磁控制系统及单机无穷大系统的仿真模型．对系统设置了静态小扰动及暂态大扰动并进行仿真。根据仿真结果分析并验证电力系统在不同的故障或扰动下,该励磁控制策略对系统静态稳定及暂态稳定的控制效果。     

同步发电机暂态过程励磁非线性控制

首先介绍了基于能量函数的最优控制系统综合李雅鲁诺夫方法和一种简单实用的非线性系统大范围线性化方法。然后根据电力系统的具体特点，将其成功地应用于同步发电机暂态过程励磁控制器的设计，为电力系统暂态稳定控制的研究作出了新的尝试。     

一种高性能的非线性励磁控制

考虑到在基于微分几何的非线性控制中，输出函数的选取会直接影响到变换后的线性空间的构成，从而影响到控制器的最终控制效果这一事实，该文提出了通过将输出函数选取为多状态变量组合形式的简便方法来解决非线性控制系统的动、静态性能的综合协调问题，从而有效地提高控制系统的整体综合性能；将此方法用于发电机的非线性励磁控制系统中，成功地找到了一种具有较高控制性能的非线性励磁控制律。仿真结果显示，该控制律既能很好地提高发电机端电压控制精度，又能有效地提高发电机组的运行稳定性，并表明所提出的控制器能有效地协调系统中各状态量的动、静态性能，具有较好的工业运用价值。     

A nonlinear geometric approach to power system excitation control and stabilization

In this paper, a unified approach to the design of a nonlinear excitation controller/power system stabilizer for a synchronous generator/infinite bus power system is presented. The approach is based on a form of state feedback linearization, known as input–output feedback linearization, which provides an exact semi-global state transformation that is valid for a large class of operating points of the power system. With this transformation, the terminal voltage becomes a linear function of the control input. The excitation controller/power system stabilizer is then synthesized by using linear controller design techniques. The controller is proven to provide small signal stability and to provide local asymptotic tracking of admissible constant reference signals for a large class of operating points. A procedure is given to tune the controller gains to provide significant damping of the power angle oscillations.     

基于自适应Terminal滑模控制方法的VSG控制

由于分布式电源并网逆变器存在的低惯性、欠阻尼特性会影响电力系统稳定性,利用考虑发电机励磁与汽门综合控制的同步发电机四阶模型,设计了基于自适应Terminal滑模控制方法的虚拟同步发电机控制方案。针对系统的2个输入变量,构造了2个非奇异的Terminal滑模函数,由于Terminal滑模函数为非线性函数,使得误差可以快速收敛,从而保证了控制器良好的控制效果。仿真结果验证了所提控制策略可以为系统提供必要的惯性和阻尼,保证系统在参数不确定和存在外界扰动情况下的鲁棒性,能够抑制振荡并提高电力系统的稳定性。     

NUMERICAL SIMULATION OF SYNCHRONOUS GENERATOR ON STEADY STATE

ABSTRACT

In its first part, this paper deals with steady state operation of a synchronous generator knowing its geometry, its magnetic characteristic, its output voltage and the field current. The second part is about the computation of the field current and load angle knowing the load of the synchronous generator, in terms of active power (P), reactive power (Q) and terminal voltage (V).

While the magnetic material characteristic is linear, the machine's equations can be solved analytically for the determination of its operating point. But when it is in a nonlinear area the problem becomes more intricate. In that case numerical modeling is very useful. In this paper we propose a model based on the simultaneous solution of electric and magnetic equations, where the latter are solved using the FEM. To consider the movement, the electric equations are expressed in d-q reference axes. As current and load angle are unknown, one has to add a new nonlinear electric equation to the classical nonlinear magnetic system. In our model the solution is obtained using the Newton-Raphson iterative procedure.

Numerical applications have been done on an EDF (Electricité de France) 1300MW synchronous generator designed by GEC.ALSTHOM. To show the validity of the model different trials have been performed, first without load, then when the machine produces active and reactive power.     

非线性励磁控制中输出函数对系统性能的影响

发现在进行非线性系统的非线性控制设计时，状态方程中输出函数的选取对线性化以后系统状态方程的形式有很大的影响，进而影响到所设计的控制器性能。在此研究结果的基础上，改进了电力系统非线性控制器的设计方法，可以在统一的非线性控制设计框架下同时对多个状态量的性能指标提出要求，兼顾受控系统多个状态量的响应特性，使系统的动态性能和静态性能能够很好地协调，实现高性能的非线性控制。将改进的设计方法应用于发电机组的励磁控制，采用逆系统非线性控制原理设计了一种具有综合性能指标的非线性励磁控制规律。将所设计的多指标非线性励磁控制律用于单机无穷大电力系统的同步发电机组中进行仿真实验，其结果表明所提出的控制器不仅能明显地提高发电机的动态稳定性，而立能准确地将发电机的端电压控制在其给定值上运行，不会因受扰而发生偏移。     

STABILITY OF D.W.R. SYNCHRONOUS GENERATOR AS AFFECTED BY FORCED EXCITATION SYSTEMS

ABSTRACT

Dynamic stability of a divided winding rotor synchronous generator Is determined by co-ordination of regulator parameters obtained by applying D-decomposition technique. Transient stability is evaluated by simulating faults like (a) sudden 3-phase short circuit, (b) sustained loss of excitation in either of the field windings. Results are compared with the transient simulation made on the same generator equipped with regulators, as described by previous authors     

基于混沌遗传NPID的TRT励磁控制器

针对PID控制器的局限性,基于非线性跟踪微分器,为TRT励磁控制系统设计了一个双环非线性PID控制器.并将混沌优化算法与遗传算法相融合,对非线性PID励磁控制器参数进行优化,解决了一般非线性PID控制器参数整定的难题.仿真结果表明,NPID控制器提高了发电机机端电压的控制精度,改善了电压的调节品质,而且增强了控制系统的鲁棒性.     

Observational linearization and tracking objective excitation control strategy based on phasor measurement unit

To improve the transient stability of multimachine power systems, observational linearization and tracking objective excitation control laws were derived from the phasor measurement unit (PMU), observational linearization, and tracking objective control theory based on synchronized coordinates and reference generator coordinates. The control strategies utilized real-time state variables obtained by PMU to linearize the state equations of the system, and then the linear optimal control strategy was used to design excitation controllers. The inaccuracy of the local linearization method and the complexity of the system models designed in the exact linearization method for nonlinear systems were avoided. Therefore, the control strategies were applied in real time. Simulation results show that the proposed method can improve the transient stability of power systems more efficiently than nonlinear optimal excitation control. Translated from Journal of Sichuan University, 2006, 38(2): 146–150 [译自: 四川大学学报 (工程科学版)]