具有失速调节的变转速风力机的动态分析与控制策略

失速调节变车风力机是非线性而且在额定风速以上不稳定的系统,风力机的跟踪控制又是分段实现的,研究其动态特性和控制策略对风力机的稳定性和可靠性尤其重要,从风力机的动力关系出发,分析了风力机在额定风速上下的运行特性,确定了相应的跟踪控制方案,并对试验风力机进行控制设计,给出了不同方案的计算机仿真结果及比较分析。     

汽轮机小岛运行事故分析及解决方法

电网发生有限故障时电厂首先的应对是机组良好的、宽负荷范围的一次调频和及时恰当的二次调频作用.电网发生故障特别是当电厂存在脱离系统而带局域电网运行的可能时,汽轮机组精确完善的超速保护控制(OPC)是维持局域电网运行的极重要功能。当电网发生严重故障发电厂孤立运行时,成功实现机组迅速稳定到额定转速并带厂用电运行是电网恢复的最佳对策。     

基于差分进化算法的燃气轮机转速模糊PID复合控制

为了改善电站燃气轮机转速控制系统的调节品质,采用模糊PID(比例积分微分调节器)复合控制,通过差分进化算法对模糊控制器参数进行寻优,基于电力系统高级仿真支撑平台(JSSC)对该方法进行了验证。试验结果表明:模糊PID复合控制无论在升速过程还是甩负荷等突变工况时,不管在超调量、过渡过程时间等动态性能上还是静态偏差等方面,转速控制结果均明显优于单纯的PID控制;当转速特性发生变化时,该控制方法表现出良好的鲁棒性。     

基于MPC的三轴燃气轮机转速负荷控制

三轴燃气轮机转速负荷控制一般采用串级PID控制方案,该方案具有较好的抗干扰性,但考虑多限制时结构显得冗余、保守。为进一步提高燃气轮机控制系统的动态性能,简化系统结构,提出了一种基于模型预测控制的串级PID-MPC方案,采用MBD的设计方法在MATLAB/Simulink平台中建立了燃气轮机模型和控制算法,利用代码生成技术产生C/C++代码在全数字仿真平台上进行了集成和验证。仿真结果表明:串级PID-MPC在负荷连续阶跃和甩负荷情况下调节时间均小于3 s,超调量不超过2.9%,与串级PID相比具有更好的动态性能,且在限制条件下控制算法单步运行最大耗时4.69 ms,平均耗时1.84 ms,具有较好的实时性。     

Maximum slew-rate governor control for impulse turbines

A deflector bang-bang and speed derivative methodology for controlling impulse turbine transients is developed. The control was implemented in a linear simulation to demonstrate its effectiveness in controlling load torque perturbations. The proposed controller strategy is implemented in a nonlinear simulation. The design was found to significantly reduce turbine off-speeds and nominal operating point settling times in both simulations     

微型燃气轮机可变论域自适应模糊PID控制

微型燃气轮机是一个多变量、非线性的复杂系统,采用常规的控制方法仅能在其稳定运行时有较好的控制效果,而在负荷变化或特定工作点运行时,由于多种耦合限制的存在,往往难以取得令人满意的控制效果。基于微型燃气轮机发电系统的动态特性,在仿真平台上建立了含微型燃气轮机及发电系统完整的数学模型,并在模型中加入了可变论域自适应模糊PID(比例、积分、微分控制)控制环节,在燃气轮机孤网带载运行状态下,研究了燃气轮机的转速、燃料量、排气温度和机械转矩等动态特性。仿真结果表明:当负荷突变时,转速能够快速达到稳定且超调量不超过1.9%,燃料量在满载时能维持在1 p.u.附近,满足燃气轮机运行要求,具有稳态性能好、动态响应快和鲁棒性强的优点。     

微型燃气轮机发电系统仿真模型研究

利用PSCAD/EMTDC软件建立了微燃机发电系统的原动机部分模型,以单机带负荷系统为例进行了微燃机动态特性仿真研究。仿真结果表明,该模型可以使微燃机在孤岛运行状态下有良好的负荷跟随特性,并能保证透平转速的恒定。模型很好地反映了微网中微燃机发电系统所具有的特性。     

Performance characteristics of part-load operations of a solid oxide fuel cell/gas turbine hybrid system using air-bypass valves

In spite of the high-performance characteristics of a solid oxide fuel cell/gas turbine (SOFC/GT) hybrid system, it is difficult to maintain high-level performance under real application conditions, which generally require part-load operations. The efficiency loss of the SOFC/GT hybrid system under such conditions is closely related to that of the gas turbine. The power generated by the gas turbine in a hybrid system is much less than that generated by the SOFC, but its contribution to the efficiency of the system is important, especially under part-load conditions. Over the entire operating load profile of a hybrid system, the efficiency of the hybrid system can be maximized by increasing the contribution of power coming from the high efficiency component, namely the fuel cell. In this study, part-load control strategies using air-bypass valves are proposed, and their impact on the performance of an SOFC/GT hybrid system is discussed. It is found that air-bypass modes with control of the fuel supply help to overcome the limits of the part-load operation characteristics in air/fuel control modes, such as variable rotational speed control and variable inlet guide vane control.     

带回热微型燃气轮机系统动态过程分析

分析了微型燃气轮机的动态数学模型,利用解析方法,求解了带回热单轴燃气轮机动态方程,对定转速和变转速两种情况下微型燃气轮机负荷变化和甩负荷的动态过程进行了仿真,提出了机组变工况动态性能优化和控制优化的途径。该研究能够为实际机组的运行和系统性能参数的合理匹配提供理论指导。     

An Autonomous System Supplied Only by a Pitch-Controlled Variable-Speed Wind Turbine

This paper presents a control strategy for a variable-speed pitch-controlled wind turbine (WT) generation scheme for the supply of an autonomous system with no energy storage units. The synchronous generator includes two three-phase stator windings displaced by 30deg that are connected to the transformer load through two dc links with voltage source inverters (VSI). Following priority rules, the load is divided into steps. Each load step can be supplied by the WT when the wind speed varies between two predefined speed levels. The first goal of the WT control system is to supply the load with constant real power under constant voltage as the wind speed varies between two levels and the second is to operate smoothly interchanging the load steps when the wind speed breaks through a speed level. There are two controllers: the inverter controller that keeps the load voltage constant and the pitch controller acting on the blade's angle. Using simulation techniques, the operation of the WT system and the efficiency of the proposed control strategy are demonstrated for a wide range of wind speeds.     

极端风况下双转子风力机降载复合控制策略

为降低双转子风力机在极端风况下的大波动载荷,基于双转子风力机气动与控制仿真系统,提出了基于独立变桨自抗扰控制器和偏航模糊控制器的降载复合控制策略,并分析了正常风况和极端风况下该策略的控制效果。结果表明：与传统PID独立变桨控制相比,在极端运行阵风和极端湍流模型下,独立变桨自抗扰控制方法使叶根挥舞弯矩标准差减小18%以上;与传统恒速偏航控制相比,在极端风向变化下,偏航模糊控制方法使偏航轴承滚动力矩标准差减小约27%。降载复合控制策略有效降低了极端风况下双转子风力机的大载荷,抑制了功率波动。     

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Frequency regulation in a generation mix having large wind power penetration is a critical issue, as wind units isolate from the grid during disturbances with advanced power electronics controllers and reduce equivalent system inertia. Thus, it is important that wind turbines also contribute to system frequency control. This paper examines the dynamic contribution of doubly fed induction generator (DFIG)-based wind turbine in system frequency regulation. The modified inertial support scheme is proposed which helps the DFIG to provide the short term transient active power support to the grid during transients and arrests the fall in frequency. The frequency deviation is considered by the controller to provide the inertial control. An additional reference power output is used which helps the DFIG to release kinetic energy stored in rotating masses of the turbine. The optimal speed control parameters have been used for the DFIG to increases its participation in frequency control. The simulations carried out in a two-area interconnected power system demonstrate the contribution of the DFIG in load frequency control.     

机械驱动用单轴燃气轮机动态模型研究

随着燃气轮机性能的不断提高,其应用范围也越来越广。除用在燃气轮机电站及联合循环电站中外,同时也越来越多地用作变转速的机械驱动动力。本文给出了作为机械驱动力的单轴燃气轮机及其控制系统模型,结合实际情况对其进行了简化,并在Matlab/Simulink环境下对升减负荷、升减转速以及甩负荷过程进行了模拟。模拟结果与实际物理过程相吻合,因此,此模型可以用于单轴燃气轮机及其控制系统的研究。     

耒阳电厂200MW汽轮机滑负荷原因分析及调速系统改造

通过对调速系统的使用分析,找出200MW机组采用高速弹性调速器为敏感元件的机械液压式调速系统滑负荷和负荷阶跃产生的原因。采用技术改造方案消除的调速系统滑负荷和负荷阶跃现象。     

基于LabVIEW的燃气轮机发电机组测控系统设计

采用基于NI CompactRIO控制器开发的燃气轮机发电机组测控系统,利用LabVIEW语言开发了具有燃机启动控制、闭环式转速控制及温度保护功能软件,对开发的测控系统进行突增和突降燃机25%负荷的试验。结果表明,本测控系统在突增或突降负荷时,使燃机最大瞬时减速或增速不超过设定转速的7%,能够在负荷变化很短时间内恢复到与最终稳态转速的偏差小于1%,满足船舶燃气轮机通用规范的要求。     

Development of a comprehensive MPPT for grid‐connected wind turbine driven PMSG

This paper proposes a comprehensive MPPT method by which extraction of maximum power from wind turbine and its subsequent transfer through various power stages and final delivery to the connected grid are realized. In the proposed system, the operation of the wind turbine at its maximum efficiency point is maintained by control of grid‐tied inverter such that the shaft speed of the generator is set to result the desired optimum tip speed ratio of the turbine. The proposed comprehensive MPPT estimates the required DC link voltage for each wind speed using a unified system model, uses a loss factor to account for the system losses, and then controls the inverter to push the WT extracted maximum power into the grid. The comprehensive MPPT is developed and is validated in MATLAB/Simulink platform in a wide range of operating wind speed. The results ascertain that the wind turbine is made to operate at its maximum efficiency point for all wind speeds below the rated one.     

水电站多机组的分散预测控制器研究

本文提出一种适于多水轮机系统的分散预测控制策略。分散控制结构能满足实际系统的物理要求,每一机组采用性能优良的水压转速联合预测控制器,并把因分散化所丢失的机组间的关联信息通过设计一扰动观测器加以补偿。通过对有水力联系的两水轮机组带孤立负荷时的仿真结果表明,这种分散预测控制器可使系统具有优良的动态响应过程。     

防止汽轮机超速对抽汽逆止门逻辑的修改

汽轮机超速事故是对电厂中发电设备破坏性最大的事故,所以发电企业对汽轮机超速的事故都尤为关注。2011年我厂#1、2机组由于发电机保护动作信号出现,机组ETS保护动作,在调阅SOE(事故追忆时)发现各抽汽逆止门关闭时间过长。后来通过对4台机组抽汽逆止门逻辑的整改,使抽汽逆止门关闭时间大大缩短。     

IEC standard based virtual wind turbine mechanical load test system

In order to conduct a systematic test over the mechanical load of the wind turbine, load measurement principles and methods have been studied according to the International Electro- technical Commission (IEC) standard, and wind turbine test scheme has been proposed. Combined with modern virtual instrument technology, a practical and reliable system for wind turbine mechanical load test has been developed. In addition to collecting various wind turbine parameters, the system can also yield a series of curves and charts ruled by IEC standards such as the capture matrix, the relation between load and wind speed, the equivalent load and load spectrum.     

Experimental study of a small wind turbine for low‐ and medium‐wind regimes

The results of an experimental assessment of a small prototype battery charging wind turbine designed for low‐ and medium‐wind regimes are presented. The turbine is based on a newly designed axial flow permanent magnet synchronous generator and a three‐bladed rotor with variable twist and taper blades. Overspeed control is performed by a furling mechanism. The turbine has the unique feature of being capable of operating at either 12, 24 or 48 V system voltage, requiring no load control in any case. In the 48 V configuration, the system is capable of providing 2 kWh day^?1 for an average wind speed as low as 3.5 m s^?1 and an air density of 85% of the standard pressure and temperature value. The experimental assessment has been conducted under field conditions with the turbine mounted on a 20 m guy‐wired tubular tower. The experimental power curves are shown to be in good agreement with a detailed aerodynamical and electromechanical model of the turbine for non‐furling conditions and for wind speeds above the theoretical cut‐in speed. In the case of the rapidly spinning load configurations, a finite power production at wind speeds below the theoretical cut‐in speed can be observed, which can be explained in terms of inertia effects. During the measurement campaigns with high loads, we were able to observe bifurcations of the power curve, which can be explained in terms of instabilities arising in situations of transition from attached to separated flow. A full experimental C_p(λ)‐curve has been constructed by operating the turbine under different load conditions and the findings are in good agreement with a variable Reynolds‐number blade‐element momentum model. The three proposed system configurations have been found to operate with a high aerodynamic efficiency with typical values of the power coefficient in the 0.40–0.45 range. Copyright © 2009 John Wiley & Sons, Ltd.