几个重要参数对数字式电子调速器调节品质的影响分析

用数学的方法对数字式电子调速器控制柴油机转速的调节过程进行了描述与分析。指出随着调速器系统的几个重要参数（比例增益系数kc积分时间常数Ti及微分时间常数Td）设定值的不同,将会得到不同的调节规律和调节品质。以一台6RTA48T—B柴油机为例,对突卸负荷后的调节过程进行了模拟计算,分析了系统这几个重要参数对系统调节过程和调节品质的影响。结论是在不至于引起过大冲击的情况下,宜采用尽可能大的Kc值和尽可能小的Ti值;而尽可能不用微分调节。     

电弧炉电极调节器的参数优化

通过对电弧炉电极等阻抗调节控制算法的分析,给出了一种实用的PID参数优化方法.电极调节时系统将测量弧流与额定弧流进行比较并计算出当前PID调节的增益系数和变积分常数进行调节.该方法是一种简单、实用的控制方法.结果表明该方法满足了电弧炉炼钢对电极调节的要求,使三相电极更平稳地工作在平衡区内,有效地降低了能耗和电极消耗.     

超临界机组协调系统的模糊增益调度预测控制

针对火电厂超临界机组多变量锅炉-汽机协调系统在大工况范围内运行具有强非线性的特点,提出了一种基于模糊增益调度的预测控制方法.通过现场试验获取多个工况点处的协调系统传递函数模型,结合增益调度和模糊逻辑推理方法建立全局自适应模糊模型,利用预测控制技术确保控制系统全局优化品质.基于模糊增益调度的预测控制方法设计火电厂超临界机...     

工业汽轮机调节级动叶气动性能优化与应用

随着计算机技术和计算流体动力学的发展,结合现代优化理论,采用全三维CFD方法进行汽轮机通流部分气动优化的工作得以实现。开展了工业汽轮机大负荷调节级叶型优化的工作。优化获得2个候选高效叶型A3_opt和A5_opt。在某台实例汽轮机机组上进行应用验证,结果表明:通流效率在广泛的负荷变化范围内均有提高,提高范围为1. 1%～5. 5%;随着调节级负荷的增加,调节级效率增益不断提高;在调节级负荷增大到一定程度后,随着调节级负荷的进一步增大,效率增益稍微降低。应用实例表明,所研究的优化方法、优化策略和优化获得的大负荷调节级动叶叶型是成功的。     

灰色预测自适应内模控制在电厂过热汽温控制中的应用

针对电厂过热汽温的大惯性、大滞后和参数时变等特性,提出了基于灰色预测的自适应内模控制方法.使用Adaline神经网络实时辨识对象的增益和时滞,克服参数时变影响.在误差反馈通道上增加灰色预测模块,根据辨识出的对象时滞的大小,动态确定误差反馈灰色预测的长度;通过超前调节,可以有效克服模型失配和外扰的影响.     

用水压补偿装置改善水轮机调速系统调节品质的研究与试验

本文用信号流图法分析水流加速时间T_w恶化水轮机调节品质的机理.阐明改善水轮机调节品质的水压补偿原理.在此基础上,导出水压补偿装置的传递函数.并用解析法证明水压补偿装置改善水轮机调节品质的效果.最后列举了水压补偿装置在电站的试验结果.     

基于风量氧量热量信号导前微分协调控制系统

针对大型火电机组频繁参与电网调峰以及煤质不稳定导致机组燃烧扰动增多,使得协调控制系统控制品质下降的问题,提出了利用风量、氧量构造热量信号,并将此信号经过微分后引入炉侧调节器,构成导前微分协调控制系统的改进方案,同时给出补偿法整定微分增益的方法,采用机组通用简化非线性动态模型利用相对增益矩阵法在系统耦合特性和等效对象特性之间进行衡量和比较,选取适合的等效对象,计算得到微分增益.结果表明：导前微分协调控制系统能够改善系统的控制品质,减小负荷变化对机前压力的扰动,有效克服制粉系统和燃料发热量变化扰动.     

带调压室的转桨式水轮机调节系统稳定性研究

采用线性控制系统稳定性理论,研究了带调压室的特桨式水轮机调节系统的稳定性,分析了协联条件、接力器时间常数Tz和导叶至桨叶转换系数Kr对系统稳定性的影响.结果表明,非协联调节工况下的稳定域及机组转速调节品质均优于协联调节工况,且随Tz的增大、Kr值减小,系统稳定域越大,为调速器参数的选择提供了理论依据.     

基于KF-MPC的光储系统双调节反馈优化控制方法

利用储能技术能够有效平抑光伏功率波动,提高光伏输出功率的稳定性.该文提出一种基于卡尔曼滤波-模型预测控制(KF-MPC)的光储系统双调节反馈优化控制方法,即将卡尔曼滤波和模型预测控制相结合,采用双调节反馈控制实现光储系统的优化控制.在卡尔曼滤波器中引入滤波调节因子,通过自适应调节卡尔曼滤波增益使储能系统在不同工况下有效...     

温度自动调节器的试验研究

温度自动调节器对柴油机的冷却系统和润滑系统的品质起到相当大的作用,因而对柴油机的经济性有一定的影响。本文通过几个典型的试验实例对温度自动调节器的动态品质和与柴油机的匹配进行了深入的分析。研究结果表明,直接式温度调节器可满足柴油机对温度调节的要求。     

柴油机两级增压等百分比流量调节旁通阀设计

针对柴油机两级增压旁通阀大范围高精度调节特性需求,开展了增压旁通偏置异型阀阀瓣型线优化设计研究,实现了等百分比流量调节特性,解决了通用快开型废气旁通阀流量调节精度低的问题,并且具有等百分比流量特性的旁通阀可以实现控制参数在全开度范围内的一致。针对不同异型阀结构,进行了流量调节特性分析,提出了多截面混合阀设计方法,通过多种阀门流量特性试验,验证了多截面混合阀有效调节范围。研究表明,优化设计的多截面混合阀流量特性与等百分比流量特性最接近,最大有效相对开度为0.73,为通用平面旁通阀的2.6倍,增益变化率缩小,大幅提升了调节精度,多截面混合阀可显著改善增压压力的调节特性,能够平稳且有效地控制可调两级增压系统的增压压力。     

Application of temperature fuzzy controller in an indirect resistance furnace

The paper presents the application results of a fuzzy controller of temperature and its rate of change in indirect resistance chamber furnaces. The method of an initial controller tuning based on the computer simulations is described, where the modelling of the furnace appears as a special problem. Further controller tuning was done based on tests performed on the real furnace. The quality of the finally-adopted controller on the real furnace is assessed by its tracking of the desired response, regulation robustness with respect to the presence of load in the furnace, as well as by a comparison with the ideal implementation of the Dahlin algorithm for classic PID control. The experimental part of the work is made using a 5 kW indirect resistance chamber furnace.     

Benchmarking and incentive regulation of quality of service: an application to the UK electricity distribution networks

Quality of service has emerged as an important issue in post-reform regulation of electricity distribution networks. Regulators have employed partial incentive schemes to promote cost saving, investment efficiency, and service quality. This paper presents a quality-incorporated benchmarking study of the electricity distribution utilities in the UK between 1991/92 and 1998/99. We calculate technical efficiency of the utilities using Data Envelopment Analysis technique and productivity change over time using quality-incorporated Malmquist indices. We find that cost-efficient firms do not necessarily exhibit high service quality and that efficiency scores of cost-only models do not show high correlation with those of quality-based models. The results also show that improvements in service quality have made a significant contribution to the sector’s total productivity change. In addition, we show that integrating quality of service in regulatory benchmarking is preferable to cost-only approaches.     

Quality regulation of electricity distribution in Italy: an evaluation study

The potential dangers of quality degradation under price-cap regulation are well recognised by regulators. In parallel with the price-cap system, the Italian regulator introduced an incentive scheme for electricity continuity of supply to apply during the period 2000–2003. The objective of this paper is to evaluate the effectiveness of this system by studying the effects of regulation on the electricity distribution industry and to identify scope for improvement of the regulation in subsequent regulatory periods. The evaluation shows that designing a regulatory system that was inherently compatible with the internal objectives of the network companies strengthened the acceptance and effectiveness of the system. Spill-over effects of quality from the monopoly to competitive markets have contributed to the effectiveness of the regulation. Quality regulation remains an innovative part of regulation and requires periodic evaluation and verification of its outcomes.     

Quality frontier of electricity distribution: Supply security,best practices,and underground cabling in Finland

Electricity distribution is a prime example of local monopoly. In most countries, the costs of electricity distribution operators are regulated by the government. However, the cost regulation may create adverse incentives to compromise the quality of service. To avoid this, cost regulation is often amended with quality incentives. This study applies theory and methods of productivity analysis to model the frontier of service quality. A semi-nonparametric estimation method is developed, which does not assume any particular functional form for the quality frontier, but can accommodate stochastic noise and heteroscedasticity. The empirical part of our paper examines how underground cabling and location affect the interruption costs. As expected, higher proportion of underground cabling decreases the level of interruption costs. The effects of cabling and location on the variance of performance are also considered. Especially the location is found to be a significant source of heteroscedasticity in the interruption costs. Finally, the proposed quality frontier benchmark is compared to the current practice of Finnish regulation system. The proposed quality frontier is found to provide more meaningful and stable basis for setting quality targets than the average practice benchmarks currently in use.     

Performance analysis of a variable structure controller for power regulation of WECS operating in the stall region

This paper deals with power regulation in variable speed wind energy conversion systems. The importance of power control in the stall region is stressed. This mode of operation is characterized by a non‐minimum phase behaviour. A variable structure controller is described that provides stability by means of speed feedback and is robust to grid disturbances and model uncertainties. Performance of the controller is investigated. A compromise arises in the design of the speed feedback gain between high and low frequency wind components rejection. Furthermore, a cut‐off frequency of the wind velocity measurement is obtained that minimizes the effect of turbulence on power regulation. Simulation results are presented, corroborating the features of the control strategy. Copyright © 2001 John Wiley & Sons, Ltd.     

On Convergence of Nonlinear Active Disturbance Rejection Control for SISO Nonlinear Systems

The active disturbance rejection control (ADRC) was proposed by Jingqing Han in the late 1990s, which offers a new and inherently robust controller building block that requires very little information of the plant. Originally, the proposal was based largely on experiments with numerous simulations on various systems of different nature. Later, the effectiveness of the control strategy has also been demonstrated in many engineering applications such as motion control, web tension regulation, and chemical processes. However, many theoretical issues, including its applicability in stabilization, output regulation remain unanswered. In this paper, we consider the nonlinear ADRC for general single input single output nonlinear systems subject to dynamical and external uncertainties. We establish conditions that guarantee the ADRC achieving closed-loop system practical stability, disturbance attenuation, and practical reference tracking. Rigorous proofs are given to show the convergence of the variables. The peaking value reduction and high-frequency noise filtering by combination of the time-varying gain in the initial stage and the constant high gain afterwards are explained by linear ADRC. Illustrative examples are also provided.     

The economic impact of strengthening fuel quality regulation—reducing sulfur content in diesel fuel

This paper investigates the impact of strengthening vehicle emission regulation on economic activities. The government attempts to use three regulation measures to protect air quality from transportation emission. The measures include the aggregate limit (bubbles), the vehicle emission standard, and the fuel quality standard. Especially, we focus on the economic impact of reducing sulfur content in diesel fuel quality standard. Sulfur content in diesel fuel is one of the main factors in worsening local air quality. The emission from diesel vehicle accounts for 51.8% of total vehicle emission in Korea. If sulfur content reduction regulation is implemented, then the petroleum industry should build more facility to produce low sulfur content diesel, leading to additional production costs and increasing prices and decreasing outputs. We use computable general equilibrium model to analyze how the sulfur reduction regulation affects economic activities and trace out local emission reduction cost and GDP loss. And we suggest the tax-recycling mechanism to mitigate the negative economic costs due to the sulfur reduction regulation.     

提高1GW超超临界机组变负荷性能的策略分析及实践

从上海电网的主要特征入手,解读本地燃煤机组在电网自动发电控制(AGC)调节中的特殊角色和所需承担的特殊责任;而1GW超超临界机组因其设备特点很难适应电网频繁调频的需求;但AGC调节是上网电厂的一项基本义务,外部形势一时很难改变,燃煤电厂需从自身寻找突破口,以期适应当今电网的调峰需求。介绍了上海外高桥第三发电厂以创新思路寻求突破点,在投产初期采用凝结水调频技术,在持续改进AGC性能期间采用高压抽汽调频技术,在兼顾大幅增减负荷和小幅频繁反向调节负荷两种方式时,通过统计找到辨识方法为策略形成提供依据,并且对单向变负荷时一次调频的反作用提出了约制的建议。