基于滑模PI控制的电动汽车集群出力与调频联合优化

电动汽车(EV)集群在参与电网调频时,持续大量的出力可能会导致系统频率出现超调现象,且会增加系统的调频成本和对EV集群的补偿成本。在保证系统频率稳定的前提下,为了协调EV集群与发电机的出力,提出了基于滑模比例-积分(PI)控制的发电机和EV集群联合优化方法,并以系统调频成本和频率稳定为目标,对EV集群的车辆投入比例进行优化。考虑私家车、公交车、出租车这3种类型EV参与电网辅助调频,建立了EV集群参与微电网调频的单区域系统模型,通过滑模PI对EV集群进行控制,在保证频率稳定的情况下,显著减小EV集群出力;进一步对EV集群车辆投入比例参数进行优化,显著降低系统的调频成本。对发电机容量充足、不足的工况进行仿真,并对比参数优化前、后的结果,验证了所提联合优化方法的有效性和经济性。

Cystic fibrosis transmembrane conductance regulator prevents ischemia/reperfusion induced intestinal apoptosis via inhibiting PI3K/AKT/NF-κB pathway

BACKGROUND Intestinal ischemia/reperfusion(I/R)injury is a fatal syndrome that occurs under many clinical scenarios.The apoptosis of intestinal cells caused by ischemia can cause cell damage and provoke systemic dysfunction during reperfusion.However,the mechanism of I/R-induced apoptosis remains unclear.Cystic fibrosis transmembrane conductance regulator(CFTR)is a cAMP-activated chloride channel.Few researchers have paid attention to its role in intestinal I/R injury,or the relationship between CFTR and intestinal apoptosis induced by hypoxia/reoxygenation(H/R).AIM To investigate the effects of CFTR on I/R-induced intestinal apoptosis and its underlying molecular mechanisms.METHODS An intestinal I/R injury model was established in mice with superior mesenteric artery occlusion, and Caco2 cells were subjected to H/R for the simulation of I/R in vivo.RESULTSThe results suggested that CFTR overexpression significantly increased the Caco2 cell viability anddecreased cell apoptosis induced by the H/R. Interestingly, we found that the translocation of p65,an NF-κB member, from the cytoplasm to the nucleus after H/R treatment can be reversed by theoverexpression of CFTR, the NF-κB P65 would return from the nucleus to the cytoplasm asdetermined by immunostaining. We also discovered that CFTR inhibited cell apoptosis in theH/R-treated cells, and this effect was significantly curbed by the NF-κB activator BA, AKTinhibitor GSK690693 and the PI3K inhibitor LY294002. Moreover, we demonstrated that CFTRoverexpression could reverse the decreased PI3K/AKT expression induced by the I/R treatment invivo or H/R treatment in vitro.CONCLUSIONThe results of the present study indicate that the overexpression of CFTR protects Caco2 cells fromH/R-induced apoptosis;furthermore, it also inhibits H/R-induced apoptosis through thePI3K/AKT/NF-κB signaling pathway in H/R-treated Caco2 cells and intestinal tissues.

基于51单片机的数字PI调节器设计

阐述基于51单片机的数字PI调节器的设计,将设计的数字PI调节器应用于运动控制系统实验平台,开展直流电动机转速单闭环实验,实验结果证实数字PI调节器的有效性。

Adjusting the Parameters of PI Regulator in All-electrical Tank Gun Control System by Computer Program

Both the traverse subsystem and the elevation subsystem of the all-electrical tank gun control system are composed of electrical drive control system respectively. The parameters of PI regulator in these electrical drive control systems affect the performance of the control system seriously. Up to now, there is not a simple and practical method for choosing regulator parameters, which are usually determined by repeated and continual readjustment. This method is low efficient, and the parameters got are not always optimal. A method for on-line adjusting the parameters of PI regulator in the electrical drive control system by computer program is introduced in this paper. The function of adjusting PI parameters of the electrical drive control system is realized by PC program written by VC++ and controlling program written by assemble language and by the communication between PC and DSP completed by the control MSCOMM in VC++6.0. The method as mentioned above which is applied for an all-electrical tank gun control system under development is proved very available, a better performance might be obtained for the all-electrical tank gun control system easily.

Effects of Growth Regulators on Biomass and the Production of Secondary Metabolites in Peppermint (<i>Mentha pi-perita</i>) Micropropagated <i>in Vitro</i>

The effects of plant growth regulators on peppermint (Mentha piperita) cultured in vitro were studied for the purpose of maximizing growth and essential oil production in micropropagated plants. The basal medium was experimentally supplemented with the auxin 4-indol-3-ylbutyric acid (IBA) and the cytokinin 6-benzylaminopurine (BAP) individually and in combination. Supplementation with BAP alone resulted in the highest values for root length, root dry weight, shoot length, and numbers of nodes, leaves, and ramifications. Treatment with IBA alone or with IBA + BAP resulted in a ~50% increase in shoot fresh weight. The production of secondary metabolites was affected only by the addition of cytokinin, which resulted in a ~40% increase in the total yield of essential oils (EOs). Similar trends were observed for yields of the major EO components (menthone, menthol, pulegone, and menthofuran). Our findings demonstrate that the application of growth regulators increases EO production and biomass concomitantly in an herbaceous species rich in commercially valuable terpenes.

基于GA的磁悬浮球系统的Anti-windup变结构PI控制

磁悬浮球系统是一个开环不稳定的强非线性系统,而且其控制输入-驱动电流必须在限定范围内变化.为了使输出的位移达到期望的位置,采用Anti-windup变结构PI控制器,结合遗传算法优化P、I、α的值,来使小球达到最理想的位置输出.实验结果表明,与常规PI控制器比较,Anti-windup变结构PI控制可以更快速稳定跟踪期望位置,振荡幅度明显减少.

基于增量式PI算法的V-M双闭环调速系统

提出了一种基于增量式比例积分(PI)算法的晶闸管-电动机(V-M)双闭环调速系统的设计与实现方法,该调速系统的主电路采用晶闸管智能控制模块进行设计,双闭环数字PI调节器采用增量式PI算法进行设计。详细分析了该调速系统主电路和双闭环数字PI调节器的设计原理,以及直流电动机电枢电流和转速采样电路、控制信号接口电路、键盘输入与LCD显示电路的设计方法。通过对比分析在不同的比例系数和积分系数时直流电动机满载运行的转速波形,验证了该调速系统的跟随特性完全满足PI参数整定规律,其设计与实现方法可推广到工业应用领域。

Predictive Functional Controller with a Similar Proportional Integral Optimal Regulator Structure:Comparison with Traditional Predic-tive Functional Controller and Application to Heavy Oil Coking Equipment

By extending the system's state variables,a novel predictive functional controller has been developed.The structure of this controller is similar to that of classical proportional integral(PI)optimal controller and in-cludes a control block that can perform a feed-forward control of future P-step set points.It considers both the state variables and the output errors in its cost function,which results in enhanced control performance compared with traditional state space predictive functional control(TSSPFC)methods that consider only the predictive output er-rors.The predictive functional controller(PFC)has been compared with TSSPFC in terms of tracking ability,dis-turbance rejection,and also based on its application to heavy oil coking equipment.The results obtained show the effectiveness of the controller.

Anti-windup PI控制器在无刷直流电机调速系统中的应用

无刷直流电机调速系统转速环通常采用PI控制器,为了克服PI控制器输出的饱和非线性影响,设计一种变结构anti-windup PI控制器,给出了系统的稳定性条件。当控制器输出处于饱和区时,将转速误差与积分器输出之差反馈到积分环节输入端,使积分器输出迅速收敛,控制器快速退出饱和区。为验证变结构anti-windup PI控制器的可行性,通过仿真实验,结果表明采用变结构anti-windup PI控制器的无刷直流电机调速系统能有效抑制饱和现象,改善系统的动静态性能。

永磁同步电机双闭环调速PI控制器及其改进设计

以永磁同步电机(PMSM)为控制对象,分析传统电流环、速度环控制下的PMSM动态性能。在传统双闭环控制的基础上,进一步研究电压前馈解耦环节的引入对控制器造成的影响。建立上述两种PMSM矢量控制(FOC)系统仿真模型,仿真结果表明,电压前馈环节的引入提高了该控制系统的动态性能和稳态性能。

Speed Regulation Method Using Genetic Algorithm for Dual Three-phase Permanent Magnet Synchronous Motors

Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the requirements of fast response,high accuracy and good robustness.In order to improve the performance of DTP-PMSM speed regulation system,a control strategy of PI controller based on genetic algorithm is proposed.Firstly,the basic mathematical model of DTP-PMSM is established,and the PI parameters of DTP-PMSM speed regulation system are optimized by genetic algorithm,and the modeling and simulation experiments of DTP-PMSM control system are carried out by MATLAB/SIMULINK.The simulation results show that,compared with the traditional PI control,the proposed algorithm significantly improves the performance of the control system,and the speed output overshoot of the GA-PI speed control system is smaller.The anti-interference ability is stronger,and the torque and double three-phase current output fluctuations are smaller.

基于PI调节的建筑电气设备电源频率自动调控方法

为解决建筑电气设备电源频率的调控切换问题,本文提出一种基于PI调节器的电气设备电源频率自动调控方法,该解决方法的创新性在于PI调节具有较强的鲁棒性,维持系统稳态的同时,还能在出现偏差时产生控制作用,以保持系统稳态。本文在MATLAB软件中搭建了排风系统,仿真结果表明:所提方法能够控制独立电源电稳处于1s以下,可实现三相与单相交流侧的电稳控制在0.02s和0.11s,具有较高的自动快速调控能力。

UPQC的非线性PI-模型预测控制策略

由于统一电能质量调节器(unified power quality conditioner, UPQC)系统复杂性高,使得其控制难度大并且动静态性能不理想。为了进一步提高UPQC的控制性能,提出了基于非线性比例积分(proportional-integral, PI)与模型预测控制(model predictive control, MPC)的混合控制策略。UPQC的混合控制策略中电压外环采用非线性PI控制器来获取更加准确的期望电流,有效地抑制了静态误差;采用模型预测控制来设计电流内环控制器,使得内环电流能更好地跟踪期望值,UPQC系统的鲁棒性更强。计算机仿真结果表明,该控制策略有效提升了UPQC动静态性能,与PI-MPC及PI-PI控制策略相比,当电网电压发生谐波污染、电压突增、电压突降时可获得更接近正弦的负载电压,当负载电流发生突变时可获得更接近正弦的电网电流。

基于分数阶PI的三相并网整流器调压优化策略

直流侧电压具有优良的动态响应与抗扰动特性是衡量三相并网整流器性能的关键。本文论述了一种基于分数阶PI调节器(FOPI)的整流器直流电压双闭环控制策略,FOPI相较于PI多了一个控制自由度,故可利用FOPI提升三相并网整流器直流电压的动态性能与抗扰动能力。首先,建立三相并网整流器在dq坐标系下的数学模型,给出了基于传统PI/FOPI的直流电压双闭环控制策略;其次,在分析水循环算法(WCA)原理的基础上,阐述了基于WCA的PI与FOPI的参数设计方法;最后,利用MATLAB仿真软件建立三相并网整流器的仿真模型,进行了相应的案例仿真与实验测试对比验证。仿真与实验对比结果表明,所述FOPI比传统PI在改善三相并网整流器直流电压的动态响应特性和抗扰动性能两个方面均更具优越性。

基于模糊PI的永磁同步电机弱磁控制策略

设计了基于模糊PI的永磁同步电机弱磁控制策略,旨在解决永磁同步电机运行过程中转速超调量大、转矩脉动大等问题,并结合单电流调节器弱磁法对系统进行弱磁扩速处理。该设计策略采用模糊PI控制算法、弱磁控制与MTPA控制相结合,利用模糊PI控制算法优化MTPA控制,提高了系统的响应性能和抗干扰能力。在MATLAB/Simulink中搭建了完善的数学模型,并通过仿真验证了该控制算法的有效性。

基于二自由度PID的三相PWM整流器调压改进策略

基于前端电压源型整流器(voltage source rectifier,VSR)与后端电压源型逆变器(voltage source inverter,VSI)级联的VSR-VSI双三相脉冲宽度调制(pulse width modulation,PWM)变换器已在电梯能量回馈系统中得到广泛应用,但前端三相VSR采用传统比例积分(proportional integral,PI)双闭环控制结构通常存在中端直流母线电压无法兼顾抗干扰性和跟踪性的问题。为此,文中提出一种基于二自由度比例积分微分(proportional integral differential,PID)的三相PWM整流器调压改进策略。首先,阐述基于VSR-VSI双三相PWM变换器级联系统的结构和工作原理,并给出前端三相VSR的传统PI双闭环控制方案及其参数设计过程,分析该方案不能兼具良好的抗干扰性与跟踪性的原因。在此基础上,给出基于二自由度PID的前端三相VSR直流调压优化策略及其参数设计方法。最后,利用软件仿真与实验测试对比结果共同验证了所述三相PWM-VSR直流调压改进策略的有效性与优越性。

一种基于PI控制的数字低压差稳压器高速可调节模型

数字低压差线性稳压器由于可以在低电源电压下工作而被广泛使用。在数字低压差线性稳压器中,其利用模数转换器和积分器进行稳压操作。但是当负载出现瞬态电压变化,其稳定时间将会很长。在PI控制系统中,积分系数大的电路建立时间很短,会产生过冲,然后输出才会稳定。积分系数小的模型输出可以直接稳定,但是建立时间太长。提出了一种高速可调节电路模型,目的是利用电压传感器和时间数字转换器(TDC),并在电路中加入2种不同积分系数的积分器。首先利用电压传感器和时间数字转换技术(TDCT)实现模数转换以得到数字信号。随后判断数字信号与基准电压,在误差很大时,控制电路选择大积分系数,输出到PI控制;误差小时,控制电路选择小的积分系数,这样可以使电路结合不同积分系数电路的优点,从而达到同时缩短电路建立时间和稳定时间的目的。

基于PI控制的蓄电池核容充电管理

变电站内蓄电池监测与核容的关键问题是对蓄电池充放电,采集电气参数来判定电池的状态。蓄电池参数的非线性、离散性和滞后性使得常规的能量管理系统无法准确快速控制核容时的充放电,特别是现有的恒压充电方式容易造成过度充电,温度骤升。通过反馈比例积分(PI)控制,采用反馈电压模式控制和分段电流模式方法将电池电压、电流和温度保持在安全范围内的同时,提升核容工作效率,保护电池健康。MATLAB/Simulink仿真显示,PI控制反馈参数可较快使蓄电池达到最佳充电状态。

基于PI调节器和电容电流反馈有源阻尼的LCL型并网逆变器闭环参数设计

基于电容电流反馈的有源阻尼是实现LCL型并网逆变器谐振峰阻尼的一种有效方法,PI调节器因其简单有效而常用于并网电流的控制。针对基于PI调节器和电容电流反馈有源阻尼的LCL型单相并网逆变器,详细分析PI调节器参数和电容电流反馈系数等闭环参数对系统性能的影响,通过对并网电流稳态误差、系统相位裕度和幅值裕度的分析,得到满足上述要求的PI调节器参数和电容电流反馈系数的取值范围,结合实际应用需要就可从中优化选取出合适的闭环参数。所提出的闭环参数设计方法不需要反复试凑,不仅可以有效阻尼LCL滤波器谐振峰,而且可以使系统具有高鲁棒性、快速动态响应性能和低稳态误差。实验结果证明了所提出的闭环参数设计方法是有效的。

永磁同步电机Anti-Windup速度控制器设计

主要针对永磁同步电机(PMSM)磁场定向控制系统中存在非线性饱和问题,分析了PI电机速度控制器Windup现象产生的过程及危害。对传统的Anti-reset Windup PI控制器进行了改进,将比例环节和积分环节对饱和影响进行了分离,从而使反馈补偿更为准确,有效提升了电机控制系统性能。通过仿真验证了可行性,并将其应用于所开发PMSM驱动控制系统中,在工程应用中取得了很好的控制效果,进一步验证了控制策略的可行性。