Application of gain scheduling for modeling the nonlinear dynamic characteristics of NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> emissions from utility boilers

A hierarchical gain scheduling (HGS) approach is proposed to model the nonlinear dynamics of NO _x emissions of a utility boiler. At the lower level of HGS, a nonlinear static model is used to schedule the static parameters of local linear dynamic models (LDMs), such as static gains and static operating conditions. According to upper level scheduling variables, a multi-model method is used to calculate the predictive output based on lower-level LDMs. Both static and dynamic experiments are carried out at a 360 MW pulverized coal-fired boiler. Based on these data, a nonlinear static model using artificial neural network (ANN) and a series of linear dynamic models are obtained. Then, the performance of the HGS model is compared to the common multi-model in predicting NO _x emissions, and experimental results indicate that the proposed HGS model is much better than the multi-model in predicting NO _x emissions in the dynamic process. This paper was presented at the 7 ^th China-Korea Workshop on Clean Energy Technology held at Taiyuan, Shanxi, China, June 25–28, 2008.     

轴流压缩机的防喘振控制

通过对轴流压缩机喘振现象和防喘振控制方法的分析,设计了一种基于变增益系数和变积分系数结合的PID调节喘振的方案。该方法有效地克服了变增益系数法系统易扰动和变积分系数法的易滞后缺点,从而提高了轴流压缩机的安全和经济性能。     

Gain-scheduling multivariable LPV control of an irrigation canal system

The purpose of this paper is to present a multivariable linear parameter varying (LPV) controller with a gain scheduling Smith Predictor (SP) scheme applicable to open-flow canal systems. This LPV controller based on SP is designed taking into account the uncertainty in the estimation of delay and the variation of plant parameters according to the operating point. This new methodology can be applied to a class of delay systems that can be represented by a set of models that can be factorized into a rational multivariable model in series with left/right diagonal (multiple) delays, such as, the case of irrigation canals. A multiple pool canal system is used to test and validate the proposed control approach.     

铝薄带"水波纹"缺陷的成因及其预防

通过对铝薄带生产中的“水波纹”特征分析,认为水波纹产生的根本原因是轧制油油膜强度不够造成的;通过调整轧制油配比来提高轧制油粘度和调整轧制油助滤剂配比来提高轧制油洁净度来提高油膜强度,从而消除铝薄带水波纹的产生。     

基于电压前馈补偿算法的小电容电源控制策略

针对小电容电源的控制问题,提出了一种基于电压前馈补偿算法的小电容电源新型控制策略.通过对两级电能变换电路的简化分析后得到了电源系统的动态数学模型,进而分析了直流母线电容和网侧电感引起的共振.基于锁频环算法提取了直流电压脉动的交流分量,从而基于系统简化模型设计了电压前馈补偿控制器,故最大限度地减少了直流母线电压纹波对负载电流的影响.基于5 k W直流电源试验平台开展了对比试验,试验结果验证了新型控制策略的性能.     

五种PWM方式对无刷电动机换相转矩脉动的分析和比较

针对五种PWM调制方式对永磁无刷电动机换相转矩脉动的大小进行了分析和比较.理论推导得到:pwm_on方式的换相转矩脉动最小;Hpwm_Lpwm方式的换相转矩脉动最大;其余三种的换相转矩脉动在其两者之间.经仿真分析和实验观测,验证了理论分析的正确性.     

电子战接收机中的自动增益控制

在电子战接收机中,采用自动增益控制,不仅可以确保系统处于较佳的工作状态,同时,也可以减少操作员的负担。电子战接收机的自动增益控制与雷达接收机不同,需要采用不同的设计,文章讨论了电子战接收机的最佳增益控制策略,并提出了基本的实现模型。     

增益自调整的神经元二自由度PID控制的SIMULINK仿真模型

该文通过编写S函数的方法建立建立增益自调整的神经元二自由度PID控制的SIMULINK仿真模型，并给出仿真结果，该仿真模型能方便地实现对增益自调整的神经元二自由度PID控制的仿真研究。     

Time division multiplexed strain sensing system by the use of dual-wavelength fiber Bragg gratings

The dual-wavelength fiber Bragg gratings (DWFBGs) accompanying with dual-wavelength pulsed laser source for strain measurement in a time division multiplexed (TDM) sensing system have been demonstrated. The accuracy up to 2.3 μ in a ±50 μ range has been achieved.     

Design of multivariable feedback systems with infinite gain margin and decoupling

This letter discusses the problem of designing a feedback compensator that attains the infinite gain margin under the uncertainties of feedback gains. A sufficient condition is given for the existence of compensators and then it is shown that the condition becomes necessary subject to the requirement that the feedback system is decoupled. The nonlinear case is also discussed.