Application of a Current and Voltage Mixed Control Mode for the New Fast Control Power Supply at EAST

A feedback control system is needed to restrain plasma vertical displacement in EAST （Experimental Advanced Superconducting Toknmak）. A fast control power supply excites active feedback coils, which produces a magnetic field to control the plasma＇s displacement. With the development of EAST, new demands on the new fast control power supply have led to an enhanced ability of fast response and output current, as well as a new control mode. The structure of cascaded and paralleled H-bridges can meet the demand of extended capacity, and digital control can reMize current and voltage mixed control mode. The validity of the proposed scheme is confirmed by experiments.

A Mixed-control Mechanism Model of Proeutectoid Ferrite Growth under Non-equilibrium Interface Condition in Fe-C Alloys

By combining the α/γ interface migration and the carbon diffusion at the interface in Fe-C alloys, a mathematical model is constructed to describe the mixed-control mechanism for proeutectoid ferrite formation from austenite. In this model, the α/γ interface is treated as non-equilibrium interface, i.e., the carbon concentration of austenite at γ/α interface is obtained through theoretical calculation, instead of that assumed as the local equilibrium concentration. For isothermal precipitation of ferrite in Fe-C alloys, the calculated results show that the rate of interface migration decreases monotonically during the whole process, while the rate of carbon diffusion from γ/α interface into austenite increases to a peak value and then decreases. The process of ferrite growth may be considered as composed of three stages: the period of rapid growth, slow growth and finishing stage. The results also show that the carbon concentration of austenite at γ/α interface could not reach the thermodynamic equilibrium value even at the last stage of ferrite growth.

Dynamic and inner-dressing control of four-wave mixing in periodically-driven atomic system

Four-wave-mixing(FWM) process is examined by using density matrix formalism in a periodically-driven atomic medium. Numerical result shows that FWM signals can be controlled by selecting different dynamic parameters of the probe field and strengths of the inner-dressing fields. It is also shown that the controllable FWM process is dominantly influenced by the evolution of atomic population difference and two-photon coherence. This dynamic and inner-dressing control of FWM is probably used for optimizing the optical nonlinear process and information processing.

Mixed H_2/H_∞ State Feedback Attitude Control of Microsatellite Based on Extended LMI Method

For the appearance of the additive perturbation of controller gain when the controller parameter has minute adjustment at the initial running stage of system,to avoid the adverse effects,this paper investigates the mixed H_2/H_∞ state feedback attitude control problem of microsatellite based on extended LMI method.Firstly,the microsatellite attitude control system is established and transformed into corresponding state space form.Then,without the equivalence restriction of the two Lyapunov variables of H_2 and H∞performance,this paper introduces additional variables to design the mixed H_2/H_∞ control method based on LMI which can also reduce the conservatives.Finally,numerical simulations are analyzed to show that the proposed method can make the satellite stable within 20 s whether there is additive perturbation of the controller gain or not.The comparative analysis of the simulation results between extended LMI method and traditional LMI method also demonstrates the effectiveness and feasibility of the proposed method in this paper.

Impact Analysis of EV Charging with Mixed Control Strategy

EVs （electric vehicles） have been widely accepted as a promising solution for reducing oil consumption, air pollution and greenhouse gas emission. The number of EVs is growing very fast over the years. However, the high adoption of EVs will impose a burden on the power system, especially for neighborhood level network. In this paper, we propose a mixed control framework for EV charging scheduling to mitigate its impact on the power network. A metric for modeling customer＇s satisfaction is also proposed to compare the user satisfaction for different algorithms. The impacts of the proposed algorithms on EV charging cost, EV penetration and peak power reduction are evaluated with real data for a neighborhood level network. The simulation results demonstrate the effectiveness of the proposed algorithms.

A new semi-active suspension control strategy through mixed H_2/H_∞ robust technique

A new semi-active suspension control strategy through mixed H2/H∞ robust technique was developed due to its flexibility and robustness to model uncertainties.A full car model with seven degrees of freedom was established to demonstrate the effectiveness of the new control approach.Magneto-rheological(MR) dampers were designed,manufactured and characterized as available semi-active actuators in the developed semi-active suspension system.The four independent mixed H2/H∞ controllers were devised in order to perform a distributed semi-active control system in the vehicle by which the response velocity and reliability can be improved significantly.The performance of the proposed new approach was investigated in time and frequency domains.A good balance between vehicle's comfort and road holding was achieved.An effective and practical control strategy for semi-active suspension system was thus obtained.This new approach exhibits some advantages in implementation,performance flexibility and robustness compared to existing methods.

Dynamic Output Feedback Control Synthesis with Mixed Frequency Small Gain Specifications

这篇论文与混合频率为线性连续时间的系统经由动态输出反馈涉及控制合成问题小获得说明。为设计动态产量反馈控制器的一个新方法被介绍以便结果靠近环的系统是 asymptotically 稳定的并且在两个有限频率范围和全部频率范围满足小获得说明的要求。设计条件以一套线性矩阵不平等(LMI ) 的答案被给。最后，一个数字例子被给与存在那个比较说明设计过程和建议方法的优点。

A novel mixed-synchronization phenomenon in coupled Chua's circuits via non-fragile linear control

Dynamical variables of coupled nonlinear oscillators can exhibit different synchronization patterns depending on the designed coupling scheme. In this paper, a non-fragile linear feedback control strategy with multiplicative controller gain uncertainties is proposed for realizing the mixed-synchronization of Chua＇s circuits connected in a drive-response configuration. In particular, in the mixed-synchronization regime, different state variables of the response system can evolve into complete synchronization, anti-synchronization and even amplitude death simultaneously with the drive variables for an appropriate choice of scaling matrix. Using Lyapunov stability theory, we derive some sufficient criteria for achieving global mixed-synchronization. It is shown that the desired non-fragile state feedback controller can be constructed by solving a set of linear matrix inequalities （LMIs）. Numerical simulations are also provided to demonstrate the effectiveness of the proposed control approach.

Highly Efficient and Stable Hybrid White Organic Light Emitting Diodes with Controllable Exciton Behavior by a Mixed Bipolar Interlayer

Highly efficient and stable hybrid white organic light-emitting diodes （HWOLEDs） with a mixed bipolar interlayer between fluorescent blue and phosphorescent yellow emitting layers are demonstrated. The bipolar interlayer is a mixture of p-type diphenyl （l0-phenyl-lOH-spiro [acridine-9,9＇-fluoren]-3Lyl） phosphine oxide and n-type 2＇,2- （1,3,5-benzinetriyl）-tris（1-phenyl-l-H-benzimidazole）. The electroluminance and Commission Internationale de l＇Eclairage （CIE1931） coordinates＇ characteristics can be modulated easily by adjusting the ratio of the hole- predominated material to the electron-predominated material in the interlayer. The hybrid WOLED with a p-type：n-type ratio of 1：3 shows a maximum current efficiency and power efficiency of 61.1 ed/A and 55.8 lm/W, respectively, with warm white CIE coordinates of （0.34, 0.43）. The excellent efficiency and adaptive CIE coordi- nates are attributed to the mixed interlayer with improved charge carrier balance, optimized exciton distribution, and enhanced harvesting of singlet and triplet excitons.

Adaptive switching control of a class of nonlinear systems based on mixed multiple models

The transient behaviors of traditional adaptive control may be very poor in general. A practically feasible approach to improve the transient performances is the adoption of adaptive switc- hing control. For a typical class of nonlinear systems disturbed by random noises, mixed multiple models consisting of adaptive model and fixed models were considered to design the switching con- trol law. Under certain assumptions, the nonlinear system with the switching control law was proved rigorously to be stable and optimal A simulation example was provided to compare the performance of the switching control and the traditional adaptive control.

Designing mixed <i>H</i>₂/<i>H</i>_&infin;structure specified controllers using Particle Swarm Optimization (PSO) algorithm

This paper proposes an efficient method for designing accurate structure-specified mixed H2/H∞ optimal controllers for systems with uncertainties and disturbance using particle swarm (PSO) algorithm. It is designed to find a suitable controller that minimizes the performance index of error signal subject to an unequal constraint on the norm of the closed-loop system. Although the mixed H2/H∞ for the output feedback approach control is considered as a robust and optimal control technique, the design process normally comes up with a complex and non-convex optimization problem, which is difficult to solve by the conventional optimization methods. The PSO can efficiently solve design problems of multi-input-multi-output (MIMO) optimal control systems, which is very suitable for practical engineering designs. It is used to search for parameters of a structure-specified controller, which satisfies mixed performance index. The simulation and experimental results show high feasibility, robustness and practical value compared with the conventional proportional-integral-derivative (PID) and proportional-Integral (PI) controller, and the proposed algorithm is also more efficient compared with the genetic algorithm (GA).

基于改进等效电路模型的直流微电网大信号稳定性分析

对高阶非线性直流微电网进行简化建模是大信号稳定性分析的有效方法。传统简化模型主要关注LC滤波器和线路阻抗等参数,难以分析换流器控制参数的影响,所建立的判据存在难以准确反映直流微电网稳定域的问题。因此,该文提出直流电压下垂控制换流器的具备完整状态变量集的改进等效电路模型,相比于传统简化模型,能更准确地刻画系统低频响应特性。基于混合势理论推导了直流微电网大信号稳定判据及其稳定域,并结合LaSalle不变集定理得到能量指标,以反映系统稳定性变化趋势。建立的稳定判据可指导控制参数优化,且能拓展到多端直流微电网的大信号稳定性分析。在多场景下仿真验证了所提改进等效电路模型和大信号稳定判据的有效性。

基于路面等级识别的车辆半主动悬架内外环控制

针对车辆在不同路面等级下对悬架动态性能与馈能特性需求不同的问题,提出一种基于RF-XGBoost路面等级识别算法的半主动悬架内外环控制策略。利用随机森林(Random Forest,RF)模型对极端梯度提升(Extreme Gradient Boosting,XGBoost)算法进行优化,搭建RF-XGBoost算法模型对路面等级进行识别。将路面等级与悬架控制策略相结合,设计外环为天地棚控制,内环为自适应滑模控制的内外环控制,实现非线性悬架的自适应控制。仿真结果表明,相比传统混合天地棚控制的悬架,内外环控制下的悬架在A级路面下簧载质量加速度降低15.52%,并实现50.4 W的振动能量回收,在B、C级路面下簧载质量加速度分别降低15.09%、16.72%,轮胎动载荷分别降低11.63%、11.42%,在D级路面下轮胎动载荷降低14.12%。台架试验的结果与仿真分析的结果基本一致,表明所设计的自适应内外环控制有效。

基于主动尾流控制的风电机群协同优化调度

针对机组间尾流效应严重影响风电机组发电效率的问题,提出了风电机组安全偏航约束计算方法、尾流特性混合半机理建模方法以及风电机群多目标协同优化调度方法。基于FAST.FARM平台完善了多自由度可控机组与尾流的动态交互集成仿真环境,对比分析了2台机组串列式排布以及华东地区某海上风电场7台机组实际排布下的协同运行优化性能。结果表明:所建立的集成仿真模型能够合理表征风电机群与空气流场的多领域动态交互特性,所提方法能够有效提升风电机群发电效能,促进经济效益、资源利用和成本控制的均衡优化。

海洋电磁发射机可控源整流电路动态性能优化

海洋电磁发射机在非理想状况工作时母线会产生冲击电压,严重时损坏开关管和滤波电容,为此提出一种混合控制策略。首先,基于dq坐标系的前馈解耦控制策略分析海洋电磁发射机可控源整流电路的动态性能,其次,通过理论证明负载扰动和无功电流iq≠0影响控制系统的动态性能,然后提出在dq电流解耦控制中引入瞬态直接电流思想的改进q轴混合控制方法,在dq电流解耦控制中引入负载电流前馈和无功电流iq≠0环节,改善了d轴电流id的响应速度,提高了控制系统的动态性能。最后,实验结果对比表明,混合控制方法在负载突变、直流侧电压给定值突变和船上柴油发电机电压跌落3种情况下,直流侧电压超调差最小,与最长调整时间相比减少了65%左右。

影响无机涂料调色的因素

无机涂料调色受粉体的种类与数量、漆料中乳液的含量与种类、分散剂的种类、硅酸盐的种类的影响。选取不同的粉体、助剂、乳液、硅酸盐对无机涂料进行平行对照实验,目测其色彩变化情况。结果表明,不同的粉体、分散剂、乳液、硅酸盐均对无机颜料的调色有一定的影响,选用400目重钙做填料最佳,WJ-70做分散剂最好,J-504B做乳液最佳,硅溶胶8802做硅酸盐最好。

考虑时变线阻的多储能SOC稳定均衡控制策略

在直流微电网中,由于线路阻抗大小差异的复杂化,难以保证各储能单元之间达到荷电状态(state-of-charge,SOC)均衡。为此,提出一种考虑时变线阻的SOC均衡改进控制策略。首先,通过线路阻抗和SOC幂指数构造的平衡因子来修正控制系数,提高SOC的辨识度。同时,利用输出电流来约束平衡因子,提高系统的抗扰能力。在SOC均衡之后,SOC平衡因子G变为1,此时依赖线路阻抗信息但不受线路阻抗变化影响,可平稳地保持电流分配。并且结合输出电流构造的电压补偿环节有效地解决了母线电压质量和SOC均衡控制效果之间的矛盾。其次,针对基于SOC均衡的改进控制策略易受恒功率负载影响的问题,利用混合势函数理论进行建模,得到稳定性判据,有利于保障系统的稳定运行。最后,仿真结果表明,所提出的改进下垂控制能够有效地消除线路阻抗的影响,提高电流分配精度,实现SOC均衡,并验证了在各种突发扰动及极端情况下所提控制策略的有效性和正确性。

考虑节点度紧致化的最优主动解列模型

为解决主动解列模型的连通性和解列模型趋于复杂化导致计算效率下降的问题,本文提出了考虑节点度紧致化的主动解列模型。首先基于单商品流的思想,提出保证孤岛连通性的解析约束;再结合主动解列自身特点和复杂网络中度的概念,提出一种模型紧致化方法以压缩混合整数规划模型的可行域;最后以切负荷与最小潮流中断之和最小为目标求取最优的解列断面。所提模型能保证孤岛内的连通性并且能够较快地求解大型系统的解列问题。3个测试系统的仿真实验表明了该模型的有效性和快速性。