Abstraction of Small Signal Equivalent Circuit Parameters of Enhancement-Mode InGaP/AlGaAs/InGaAs PHEMT

An extraction method of the component parameter values of an enhancement-mode InGaP/AIGaAs/In-GaAs PHEMT small signal equivalent circuit is presented,and these component parameter values are extracted by using the EEHEMT1 model of IC-CAP software. The extraction results are verified by ADS software,and the DC I-V curves and S parameters simulated by ADS are basically accordant with those of the test results. These results indicate that the EEHEMT1 model can be used for extracting the component parameters of an enhancement-mode PHEMT.

In Situ Acquisition of Equivalent Circuit Parameters of Crystal Resonance during Copper Deposition and Dissolution in Acidic Solution by Electrochemical Quartz Crystal Impedance System

Electrochemical quartz crystal impedance system (EQCIS) which allows in situ dynamic quartz crystal impedance measurement in an electrochemical experiment was developed by combining an HP 4395A Network/Spectrum/Impedance analyzer with an EG&G M283 potentiostat. Equivalent circuit parameters of crystal resonance change significantly during electrodeposition and dissolution of copper in 0.1 mol/L H2SO4 aqueous solution in a cyclic potential sweep experiment, which is explained with an overall picture of mass loading, solution density and viscosity, etc..

Small-Signal Equivalent Circuit Modeling of a Photodetector Chip

A small-signal equivalent circuit model and the ted. The equivalent lumped circuit, which takes the main extraction techniques for photodetector chips are presen- factors that limit a photodetector＇s RF performance into consideration,is first determined based on the device＇s physical structure. The photodetector＇s S parameters are then on-wafer measured, and the measured raw data are processed with further calibration. A genetic algorithm is used to fit the measured data, thereby allowing us to calculate each parameter value of the model. Experimental resuits show that the modeled parameters are well matched to the measurements in a frequency range from 130MHz to 20GHz, and the proposed method is proved feasible. This model can give an exact description of the photodetector chip＇s high frequency performance,which enables an effective circuit-level prediction for photodetector and optoelectronic integrated circuits.

Simulation of second-order RC equivalent circuit model of lithium battery based on variable resistance and capacitance

With the rise of the electric vehicle industry,as the power source of electric vehicles,lithium battery has become a research hotspot.The state of charge(SOC)estimation and modelling of lithium battery are studied in this paper.The ampere-hour(Ah)integration method based on external characteristics is analyzed,and the open-circuit voltage(OCV)method is studied.The two methods are combined to estimate SOC.Considering the accuracy and complexity of the model,the second-order RC equivalent circuit model of lithium battery is selected.Pulse discharge and exponential fitting of lithium battery are used to obtain corresponding parameters.The simulation is carried out by using fixed resistance capacitance and variable resistance capacitor respectively.The accuracy of variable resistance and capacitance model is 2.9%,which verifies the validity of the proposed model.

On-line detecting of transformer winding deformation based on parameter identification of leakage inductance

Transformers are required to demonstrate the ability to withstand short circuit currents.Over currents caused by short circuit can give rise to windings deformation.In this paper,a novel method is proposed to monitor the state of transformer windings,which is achieved through on-line detecting the leakage inductance of the windings.Specifically,the mathematical model is established for online identifying the leakage inductance of the windings by applying least square algorithm(LSA) to the equivalent circuit equations.The effect of measurement and model inaccuracy on the identification error is analyzed,and the corrected model is also given to decrease these adverse effect on the results.Finally,dynamic test is carried out to verify our method.The test results clearly show that our method is very accurate even under the fluctuation of load or power factor.Therefore,our method can be effectively used to on-line detect the windings deformation.

Parameter Estimation of Single Phase Core Type Transformer Using Bacterial Foraging Algorithm

The electrical circuit equivalents of magnetic device structures such as transformer require an exact knowledge of its parameters. Efficient parameter estimation technique is essential to obtain the equivalent circuit parameters of transformer because the parameters are used to manipulate parasitic elements and to obtain the enhanced circuit performance. In this paper, Bacterial Foraging Algorithm (BFA) has been applied to estimate the equivalent circuit parameters of single phase core type transformer. The information of open Circuit (OC) and Short Circuit (SC) tests has been utilized in BFA algorithm. The effectiveness of the proposed approach has been tested with a sample transformer and the simulation results are compared against the conventional method. The numerical results show that the proposed approach outperforms the conventional method in the aspects of solution quality.

An Improved Parameters Extraction Method for Dumbbell-Shaped Defected Ground Structure

The paper presents an improved equivalent circuit parameters extraction method for the dumbbell-shaped defected ground structure (DGS). The new extraction parameters equations are obtained in closed-form expressions, which contain S11 and S21. The DGS unit with center frequency of 5 GHz is designed and fabricated on a TLX substrate with thickness of 1 mm and dielectric constant of 2.55. The circuit simulated results are in good agreement with the measured results. This parameters extraction method can be widely used for the design and analysis of DGS .

一种基于ISBO算法的锂离子电池等效电路模型辨识方法研究

锂离子电池等效电路模型的参数辨识方法对模型精度有较大的影响。针对缎蓝园丁鸟优化SBO(satin bowerbird optimization)算法收敛精度低和收敛速度慢的问题,提出一种改进的缎蓝园丁鸟优化ISBO(improved satin bowerbird optimization)算法。采用惯性权重、柯西变异、高斯变异和贪婪选择策略来提高ISBO算法的收敛精度,并利用标准测试函数对其收敛性能进行验证。结合电池充放电数据,将提出的ISBO算法用于锂离子电池等效电路模型的参数辨识。实验结果表明,与SBO和自适应权重粒子群优化算法相比,ISBO算法参数辨识精度较高且辨识精度不受电池工况的影响。

基于HPPC-FFRLS的锂电池等效模型参数在线辨识

目的为了实现锂离子动力电池的高精度状态监测与分析,方法针对锂离子动力电池二阶RC等效电路模型的参数在线辨识展开研究。搭建锂离子动力电池二阶RC等效电路模型;利用开路电压法与安-时积分算法相结合的方式进行电池荷电状态(SOC)评估;通过HPPC测试实验数据进行等效电路模型的离线参数辨识;以离线辨识结果作为系统状态初值,结合带遗忘因子的递推最小二乘算法(FFRLS)对锂离子动力电池二阶RC等效电路模型参数进行在线辨识;利用Simulink搭建电池状态监测和充放电控制仿真系统,对基于在线辨识参数的模型进行仿真测试;利用可编程电源和电子负载搭建实验平台。结果对比在线辨识参数的系统仿真输出、离线辨识参数的系统仿真输出和实验数据,结果表明:基于HPPC-FFRLS在线辨识的模型仿真输出的误差相对于HPPC实验法减小了50%;在线辨识策略克服了环境温度、电池老化、充放电倍率等因素对参数的影响;仿真初期系统波动明显减小,等效模型系统动态跟踪具有更高的精度,鲁棒性更好。结论基于HPPC-FFRLS的锂电池等效模型在线辨识保证了模型参数的有效性,简化运算量的同时提高了模型精度。

基于黏菌优化算法的水轮机调节系统控制参数优化研究

为改善水轮机调节系统的控制性能,基于等效电路法建立了全流道引水系统数学模型,结合水轮机、发电机及调速器模型构建水轮机调节系统的整体模型。在此基础上,引入黏菌优化算法对水轮机调速器PID参数实施优化。最后,在不同工况下进行仿真,仿真结果表明,SMA算法收敛速度快,寻优能力强,基于此算法的调速器使水轮机调节系统具有更好的动态稳定性,研究结果为实际工程应用提供了参考。

利用改进SCE算法的锂离子电池参数辨识

针对传统参数辨识方法中存在的易陷入局部最优和精度低问题,提出一种改进洗牌复杂演化算法(shuffed complex evolution, SCE).首先,提出描述电池的动态特性的二阶RC等效电路模型,并根据恒流放电工况测试数据集进行锂离子电池等效模型确定待辨识参数.其次,将模型模拟端电压值与电池真实测试端电压均方根误差作为目标函数,并通过所提出的优化算法来寻找模型最优参数.最后,使用DST、 FUDS的锂离子电池动态工况数据集进行仿真验证,并与粒子群算法、灰狼算法、遗传算法进行比较.仿真结果表明,本方法在辨识精度方面具有优势,算法的参数辨识均方根误差(ERMS)平均值是0.016 6 V,相比较其他优化算法,分别降低了7.8%、 8.3%、 14.9%.

基于等效电路模型的云端动力电池寿命估计

由于目前动力电池管理系统(battery management system,BMS)存在存储小、算力低等问题,仅依靠BMS估计出的容量误差会随电池荷电状态(state of charge,SOC)累计误差增大而逐渐增大。为实现动力电池寿命准确估计,提出了基于等效电路模型(equivalent circuit model,ECM)的动力电池容量估计方法。模型基于开路电压(open circuit voltage,OCV)和SOC的关系,直接建立1阶RC模型和容量联系;通过粒子群优化算法(particle swarm optimization,PSO)寻优最小仿真端电压与实际端电压的均方根误差(root-mean-square error,RMSE),此时辨识结果为初步估计容量,结合多项式回归(polynomial curve fitting,PCF)控制卡尔曼滤波(kalman filter,KF)对辨识结果进行了优化。最后对云端实车与传统方法测得的容量进行对比验证,二者的RMSE小于3%且最大绝对误差小于2 Ah。与现有方法相比,该方法能够不单依赖BMS数据准确估计容量。同时,对于实车等复杂场景的应用做出了优化,可以实现实车场景下的容量精确估计。

基于高阶EKF的锂电池SOC测算精度研究

锂电池荷电状态是电池管理系统运行的前提和核心任务,为能够准确跟踪测算电池SOC值,以18650-20R型锂电池为主要研究对象,建立二阶Thevenin等效电路模型,经脉冲特性实验对电路模型参数进行辨识,在恒流、脉冲放电及Fuds工况下验证模型的准确性,并在此基础上实现了利用一阶、二阶及高阶EKF算法对电池荷电状态的估计。最后通过Matlab仿真结果验证,高阶EKF在锂离子电池动静态SOC测算时均具有更高的测算精度。

基于自适应多层RLS的锂离子电池参数辨识

电池参数的准确辨识是电动汽车电池管理系统实现高精度状态估计的基础。针对遗忘因子递推最小二乘法(forgetting factor recursive least squares,FFRLS)辨识变化电池参数时精度不足的问题,本文提出以层数形式更新参数的自适应多层递推最小二乘(adaptive multi-layer recursive least squares,AMLRLS)电池在线参数辨识方法。AMLRLS算法以第L-1层辨识参数的电压误差作为第L层的目标值,递推分离出电压误差中的参数量,以所有层的参数量之和作为一个数据点的辨识结果,形成多层RLS结构更新参数。针对每一次辨识算法都计算至最大设置层的问题,设计层数选择器,将第一层FFRLS辨识结果的电压误差作为层数选择器的输入量,以电压误差大小自适应选择层数,减小计算量。搭建电池模型,仿真验证AMLRLS的参数跟踪能力。仿真结果表明,AMLRLS的参数误差比RLS最大降低了69%,比AFFRLS (adaptive forgetting factor recursive least squares)最大降低了46.5%。在实验验证中,AMLRLS在DST (dynamic stress test)工况下相较其他算法电压均方根误差和平均绝对误差最大降低了43.9%和32.1%,不同电流、不同温度和不同初始SOC条件下的实验结果验证了AMLRLS具有较强的适用性。最后,实验比较了各算法的计算时间,相较于未设置层数选择器的情况,AMLRLS在DST工况下计算时间缩短了37.4%,在FUDS下缩短了28.6%,减少了电池管理系统的计算负担。

小波包分解重构的励磁变压器整流谐波附加损耗计算

谐波损耗是造成励磁变压器安全事故的主要原因之一,损耗值过大易影响正常变电和输电,为此提出基于小波包分解重构的励磁变压器整流谐波附加损耗计算方法。通过获取小波包分解和重构系数,分析励磁变压器两种谐波附加损耗;利用开路和短路实验得到励磁变压器等效电路参数,采用小波包分解重构算法,计算不同谐波次数下的电阻和电抗并与基准值对比,得到励磁变压器整流谐波附加损耗值。最后,选取某种型号的励磁变压器,利用所提方法计算其在不同谐波次数下的附加损耗值,结果表明,得到的损耗值计算结果与实际结果非常接近,验证了所提方法具有较高的实用价值。

模拟电子电路的两端口网络阻抗等效变换

“模拟电子技术”中的很多基本电路都可视为三端子两端口网络。在学习过程中,为有效分析其输入-输出特性,往往需要对其进行输入回路和输出回路的拆分式解耦等效分析,而阻抗参数等效变换成为一大难点。基于电路理论基础知识,对三端子两端口网络的串联式和并联式阻抗参数等效变换进行了详细推导,并将所提的参数等效变换方法应用于三个典型模拟电路的特性分析,有效简化了电路分析过程。

金属化膜电容元件宽频特性研究

金属化膜电容器被广泛使用在换流阀等电工装备中,在电力电子开关快速动作的影响下,电容器将承受高频冲击,因此有必要研究宽频范围内电容器的特性。本文以单个电容元件为研究对象,使用数字电桥对20 Hz~2 MHz范围内电容元件的阻抗特性进行了测量,通过数据拟合和实验测量结合的方式建立了等效电路模型,并对不同频率下的阻抗特性和等效电路参数进行了分析。研究结果表明:在低频(<150 kHz)下,参数恒定的等效电路模型可准确地描述电容元件的阻抗特性和内部物理过程;而在高频(>150 kHz)下,电容元件内部不同区域的电流分布将发生变化,导致电容元件的等效电感和等效电阻等参数发生频变,引起阻抗特性发生变化。本文结果可对分析高频冲击下电容器劣化机理提供指导。

感应电动机等效电路参数获取方法及应用

基于感应电动机型号Y2-315M-4,分别采用试验法、仿真法和计算法获取感应电动机等效电路参数,研究分析三种方法的特点和适用场合。基于Simulink中现有感应电动机模型,将试验法、仿真法和计算法获取的感应电动机等效电路参数应用于模型。通过Simulink仿真计算分析可知,仿真法的等效电路参数不适用于Simulink感应电动机模型,计算法的等效电路参数使仿真结果更接近额定值。对感应电动机控制和特性的研究具有参考价值。

基于暂态数据戴维南等值参数辨识的时变广义短路比计算方法

广义短路比能有效反映多馈入直流系统受端交流电网的强度,其计算通常基于直流馈入节点处受端交流电网的戴维南等值导纳矩阵,忽略了交流电网各元件动态对电网强度的影响。本文提出了一种基于暂态数据戴维南等值参数辨识的时变广义短路比计算方法,将隐含系统元件动态特性的端口节点电压与注入端口节点功率作为辨识数据,基于多端口戴维南等值模型与最小二乘法辨识受端交流电网时变导纳矩阵,进而计算出时变广义短路比,准确地反映了系统动态对受端交流电网强度的影响。最后,以单馈入直流系统算例验证了方法的精确性,以某省级电网算例验证了其实用性,分析了负荷动态特性对时变广义短路比的影响。

基于等效电路模型参数计算的光伏组件隐裂故障诊断方法

基于等效电路模型参数计算,提出一种光伏组件隐裂故障诊断方法。通过分析隐裂、热斑、电势诱导衰减(PID)和老化故障的产生和演化机理,研究不同故障对光伏组件输出特性的影响作用、模型参数的变化规律及其差异性。建立包含正/反向特性的光伏组件等效电路模型,根据模型参数计算结果,确定故障诊断特征量,提出隐裂故障的诊断方法。实验结果表明:所得光伏组件等效电路模型参数计算结果能够较高精度地拟合实验获得的I-V特性曲线;所确定的故障诊断特征量能够有效表征隐裂的发生和演化过程;所提故障诊断方法能够实现可靠的隐裂故障原因判定和程度估算。