Flexible predictive power-split control for battery-supercapacitor systems of electric vehicles using IVHS

The utilization of traffic information received from intelligent vehicle highway systems(IVHS) to plan velocity and split output power for multi-source vehicles is currently a research hotspot. However, it is an open issue to plan vehicle velocity and distribute output power between different supply units simultaneously due to the strongly coupling characteristic of the velocity planning and the power distribution. To address this issue, a flexible predictive power-split control strategy based on IVHS is proposed for electric vehicles(EVs) equipped with battery-supercapacitor system(BSS). Unlike hierarchical strategies to plan vehicle velocity and distribute output power separately, a monolayer model predictive control(MPC) method is employed to optimize them online at the same time. Firstly, a flexible velocity planning strategy is designed based on the signal phase and time(SPAT) information received from IVHS and then the Pontryagin’s minimum principle(PMP) is adopted to formulate the optimal control problem of the BSS. Then, the flexible velocity planning strategy and the optimal control problem of BSS are embedded into an MPC framework, which is online solved using the shooting method in a fashion of receding horizon. Simulation results verify that the proposed strategy achieves a superior performance compared with the hierarchical strategy in terms of transportation efficiency, battery capacity loss, energy consumption and computation time.

Synthetical Efficiency-based Optimization for the Power Distribution of Power-split Hybrid Electric Vehicles

Now the optimization strategies for power distribution are researched widely, and most of them are aiming to the optimal fuel economy and the driving cycle must be preknown. Thus if the actual driving condition deviates from the scheduled driving cycle, the effect of optimal results will be declined greatly. Therefore, the instantaneous optimization strategy carried out on-line is studied in this paper. The power split path and the transmission efficiency are analyzed based on a special power-split scheme and the efficiency models of the power transmitting components are established. The synthetical efficiency optimization model is established for enhancing the transmission efficiency and the fuel economy. The identification of the synthetical efficiency as the optimization objective and the constrain group are discussed emphatically. The optimization is calculated by the adaptive simulated annealing （ASA） algorithm and realized on-line by the radial basis function （RBF）-based similar models. The optimization for power distribution of the hybrid vehicle in an actual driving condition is carried out and the road test results are presented. The test results indicate that the synthetical efficiency optimization method can enhance the transmission efficiency and the fuel economy of the power-split hybrid electric vehicle （HEV） observably. Compared to the rules-based strategy the optimization strategy is optimal and achieves the approximate global optimization solution for the power distribution. The synthetical efficiency optimization solved by ASA algorithm can give attentions to both optimization quality and calculation efficiency, thus it has good application foreground for the power distribution of power-split HEV.

Dynamics of a Dual Power-split Transmission Based on Loaded Tooth Contact Analysis

In order to implement the dynamic characteristic of a dual power-split transmission, a dynamic me- chanics model is built. Firstly, according to the method of theoretical analysis of the tooth contact analysis （TCA） and loaded tooth contact analysis （LTCA）, the actual meshing process of each gear pairs is simulated, and the time-varying mesh stiffness excitations are obtained, which can improve the numerical precision. Second- ly, by using the lumped mass method, the bending-torsional coupling three dimensional dynamic model of the dual power-split transmission is established, and the identical dimensionless equations are deduced by elimina- ting the effect of rigid displacement and the method of dimensional normalization. Finally, by the method of the fourth order Runge-Kutta algorithm with variable step lengths, the responses of this system in a frequency domain and time domain are obtained, and the dynamic load change characteristics of each gear pairs are analyzed. The results show that the establishment, solution and analysis of the system dynamics model could provide a basis for the dynamic design, and have an important significance for the dynamic efficiency analysis and dynamic perform- ance optimization design of the dual power-split transmission.

高功率微波大口径相控阵天线拍波辐射方法研究

相控阵天线是未来高功率微波辐射系统的重要形式之一,是当前研究的热点。为了获得超高等效全向辐射功率,高功率微波天线均为大口径形式。而大口径相控阵天线在辐射高功率微波拍波过程中,存在波束分裂、增益下降问题。针对该问题,本文提出了一种大口径相控阵天线拍波辐射结构,采用“子阵-面阵”两级馈电形式,解决了拍波辐射过程中波束分裂问题,有效提高了高功率微波系统的综合性能。该方法极大地节约了移相器数量,节省了系统成本,降低了系统复杂度,有利于实现高功率微波系统的小型化,提高系统的可靠性。

混合动力汽车功率分流传动系统扭转振动及其影响因素研究

针对某款混合动力汽车,综合考虑发动机、电机、复合行星齿轮机构、离合器、减速器、差速器和半轴等部件,采用集中质量法建立功率分流传动系统动力学模型。在此基础上,分析不同运行工况下传动系统固有频率和振型,分别研究电机和发动机激振频率与传动系统固有频率之间的关系,仿真分析扭转减振器刚度对传动系统固有频率的影响规律,通过改变扭转减振器刚度从而使得传动系统共振转速远离发动机常用工作区。

功率分流混合动力系统模式切换连续瞬态冲击机理及其性能客观评价

针对功率分流混合动力系统模式切换过程连续瞬态冲击机理尚不明确且缺乏客观评价指标和方法的问题,本文探究了模式切换连续瞬态冲击机理及其性能客观评价方法。首先,结合动力传动系统高动态性能测试台架,建立了考虑转矩过零、齿轮副啮合时变刚度、齿隙及驱动电机转矩脉动的功率分流混合动力专用变速器(DHT)瞬态扭振模型;其次,研究了DHT模式切换过程转矩过零变化机理,提出了考虑转矩过零次数和模式切换时间的连续瞬态冲击性能时域评价指标,并采用短时傅里叶变换方法建立了基于冲击度时频特性的频域评价指标;最后,以纯电动向功率分流混动模式切换过程为例,采用变异系数法对不同加速踏板开度和齿隙影响下的连续瞬态冲击性能进行了客观分析评价。结果表明,功率分流DHT动力输出端转矩频繁过零和齿隙间的耦合作用是引发模式切换过程连续瞬态冲击的主要原因,减小齿隙可降低最大振幅频率100~200 Hz范围内的连续瞬态冲击;同时,根据综合评价得分对比,得到了模式切换过程连续瞬态冲击性能优化参数,本研究可为功率分流混合动力系统模式切换平顺性协调控制策略优化提供支撑。

拖拉机液压功率分流无级变速箱设计

为适应拖拉机复杂的作业工况并提高其作业效率,提出一种单行星输入耦合型液压功率分流无级变速箱的设计方案。依据拖拉机配套动力与速度要求进行变速箱参数设计与结构设计,基于SolidWorks构建变速箱虚拟样机,并基于AMESim构建变速箱传动系统模型,对其整机调速特性进行分析。研究结果表明:该变速箱可以实现拖拉机在0~30 km/h范围内的无级调速,且在犁耕等重点工况下具有较小的液压分流功率从而实现节能;该变速箱在段位切换时需要将泵马达排量比从1快速调制-0.85,通过快速的马达反向实现行星排复位与换段前后的速度衔接。对我国无级变速拖拉机的国产化设计与应用具有一定的参考价值。

功率分流式混合动力汽车整车参数匹配与优化研究

针对功率分流式混合动力汽车,首先根据整车设计参数及动力性能目标要求,分别对电机、动力电池组、发动机、主减速器和行星排等传动系统部件进行参数匹配,并运用AVL-Cruise软件建立目标车辆整车模型;其次在满足动力性能目标的前提下,运用AVL-Cruise和Isight软件搭建联合仿真模型,分别采用粒子群优化算法和多岛遗传算法,将行星排特征参数和主减速器传动比作为优化参数,百公里油耗和电耗加权之和作为优化目标进行优化研究,并对比分析2种优化算法的计算结果来获得兼顾动力性能和经济性的最优结构参数,为研究功率分流式混合动力汽车传动系统提供理论依据。

无线携能通信下mmWave协作通信小单元的能效最优策略

针对无线携能通信(SWIPT)网络中的能量与信息同时传输阶段的优化问题,以最大化链路能量效率为目标,提出一种SWIPT下mmWave协作通信小单元的能效最优策略。该策略在最小链路传输速率和最小收集能量的联合约束下,在能量受限型用户设备的接收端采用功率分流工作模式,通过优化发射功率控制和功率分流因子,最大化系统链路能量效率。针对原问题是一个非凸的分式规划问题,具有NP难性质,采用Dinkelbach方法将目标函数转化为易于求解的凸优化问题,并设计一个交叉迭代的算法求出最优解。仿真实验结果表明,提出的策略在优化系统能量效率性能上要优于传统功率控制方法和最大发射功率法。

多种构型超临界CO_(2)循环热力学解构分析与参数优化

新型超临界CO_(2)(S-CO_(2))循环可通过流程改良提高效率,构型复杂多样。为了直观阐明各种流程改良措施对循环效率提升的作用机制,本文将预压缩、后压缩、再压缩、间冷、再热等五种构型的S-CO_(2)循环解构为若干热功转换过程,建立各解构过程与循环效率之间的关联方程,进而开展流程参数优化。研究结果表明,预压缩、后压缩和再压缩方案均是通过增加压缩耗功,减少吸热量实现循环效率提升,其中再压缩方案效果最优,再压缩流量优化后循环效率提高5.1%;采用部分间冷方案,可有效降低压缩功耗,同时避免高品位热量贬值,间冷压力优化后循环效率提高2.2%;再热方案在不改变压缩耗功的前提下,增加透平出功,再热压力优化后循环效率提高1.9%;最后,循环联用再压缩、间冷和再热三种节能措施,可使效率提高9.3%。

齿轮传动系统可靠性分配数字化设计与研究

随着齿轮传动系统向着高复杂性、多传动样式和高可靠性等方向发展,快速准确地对齿轮传动系统进行可靠性分配变得越来越重要。针对现有可靠性分配方法存在的考虑因素不全面、同一参数不同分配方法变化范围不统一、不便于数字化软件开发等问题,提出了改进电子设备可靠性咨询组(Advisory Group on Reliability of Electronic Equipment,AGREE)分配法,扩展了评分分配法;探讨了可靠性分配方法的数字化特征,建立了齿轮传动系统的基本可靠性与任务可靠性模型,研究了可靠性模型自动生成的遍历算法;开发了定轴轮系、行星轮系和混合轮系可靠性快速分配的数字化平台,设计了输入模块、计算模块、结果显示模块和输出模块等4个独立模块;通过与实例结果的比较,该软件计算结果的准确性得到了验证;同时也实现了齿轮传动系统可靠性分配的参数化建模与自动化生成算例报告等功能,提高了可靠性分配模型精度和计算效率。

Study of Series-Parallel and Power-Split DHT for Hybrid Powertrains

Dedicated hybrid transmission(DHT)is the developing trend of hybrid transmissions.This paper studies different types of DHTs regarding the structure,function,and performance.Firstly,the structure and function of different well-known DHTs in the market are discussed and analyzed.Through the analysis,the reasonability and necessity of the different modes and the electric motor power requirements that lie behind different DHTs are derived.Secondly,the dynamics of different DHTs are further compared with the driving areas in different modes under different driving conditions.Then,the basic or minimum dynamic requirements are defined and taken into consideration before the economic comparison.To ensure the effectiveness of the comparison,the optimization of the configurations for each kind of DHT is carried out with the modular simulation model.The economic comparison is conducted under the premise of excluding the influences of the configurations in the results.Finally,the sensitivity and influence of different engine characteristics for different DHTs are studied to find out the sensibilities of the two kinds of DHTs with engine technology.Through these studies,the essential differences and features of different DHTs can be derived to help better understand the decision in choosing the technical route for the original equipment manufacturers.

Model-Based Double Closed-Loop Coordinated Control Strategy for the Electro-Mechanical Transmission System of Heavy Power-Split HEVs

The dual-mode electro-mechanical transmission(EMT)system is a crucial part of power-split hybrid electric vehicles(HEVs),especially for the heavy HEVs.To improve the precision of the system power distribution and the response speed of the electric power supply,a model-based double closed-loop coordinated control strategy is proposed.As the basis of the proposed control strategy,an EMT system model,particularly of an electrical system,is established first.The proposed control strategy includes the power distribution strategy,battery power closed-loop feedback control strategy,and motor coordinated control strategy.To verify the feasibility of the proposed control strategy,simulation and experiment are performed.The results indicate that the proposed control strategy can realize the expected power distribution by coordinating generators and motors and achieve rapid and stable electric power supply.

10 bit高速低功耗SAR ADC设计

基于TSMC40 nm工艺,提出一种高速低功耗逐次逼近型模数转换器。设计电路采用全差分结构,基于vcm-based电容拆分技术解决先进工艺下难以设计精准VCM电平和复杂逻辑的问题,采用double-tail动态比较器实现高速和低功耗,采用TSPC触发器设计SAR逻辑进一步提高速度和降低功耗,采用异步时序,通过环路自身产生比较器时钟,不需要外接时钟信号,降低设计复杂度。在150 MHz采样频率,1.1 V电源电压,奈奎斯特的输入频率下,对该设计进行仿真,仿真结果表明,SAR ADC的ENOB=9.93 bit,SNDR=61.6 dB,SFDR=78.6 dB。

双流耦合构型混合动力拖拉机旋耕工况控制策略研究

大功率拖拉机作业时载荷冲击会造成发动机的输出转矩大范围波动,为减小载荷冲击对拖拉机动力单元的影响,提出以发动机和双电机为动力源的拖拉机双流耦合动力系统构型,以减小载荷冲击引起的动力传动系统换挡频次。基于Haar小波分解提出了基于功率预测的转矩分配策略,首先记录拖拉机的作业参数,基于径向基神经网络对拖拉机旋耕作业时的功率需求进行预测,由Haar小波变换确定高频和低频转矩需求值的范围,并分别由电机和发动机提供。最后,通过硬件在环试验对提出的动态转矩分配进行了可行性验证,测试结果表明:提出的基于神经网络功率需求预测模型对行驶端和动力输出端(Power take-off,PTO)的功率进行预测,实际值和预测值均方根误差分别占最大功率的7.6%和7.9%;提出的转矩分配策略能够应对拖拉机旋耕时的载荷波动。发动机转矩波动与传统构型相比减小35.0%,有效地缩小了发动机转矩波动范围,缓解了拖拉机作业时载荷冲击对发动机的影响。

牵引供电技术研究现状及关键性技术

我国电气化铁路里程稳居世界第一。牵引供电系统作为电气化铁路的能量心脏,其整体性能的优劣直接影响铁路的安全、稳定、经济运营。我国现有牵引供电系统面临着严重的电能质量问题,以及大量电分相制约列车速度等问题。为此,本文针对既有的分相供电系统与发展中的同相供电系统,分别从工作原理、发展现状、面临问题、关键技术等方面进行系统地梳理归纳。通过分析现有研究的成果以及不足之处,总结出构建新一代牵引供电系统仍需完善的关键性技术与未来研究趋势。希望为相关领域学者进行更深入的研究提供借鉴与参考。

基于功率分离接收机方案的低复杂度信号检测算法

为了解决基于分离接收机架构下的移动通信系统中信号检测复杂度较高的问题,提出一种低复杂度的信号检测算法。首先,考虑天线噪声、后级处理噪声和功率分离因子的影响,设计分离接收机架构,并基于三维接收信号建立简化的二维接收信号模型。然后,在变换坐标系下表征二维接收信号的联合概率密度函数,进而提出基于最小距离的低复杂度的信号检测算法。最后,分析分离接收机方案相对于传统相干接收机的联合处理增益。理论分析表明,相比于传统的基于三维接收信号的检测算法,所提信号检测算法具有较低的计算复杂度。仿真结果表明,在一定的功率分离因子下,低复杂度信号检测所获得的近似误符号率(SER)与最优的SER性能接近,且分离接收机架构下的SER性能优于传统的相干接收机方案。

互联网背景下对分课堂教学在《电力系统自动化》课程中的实践研究

基于互联网背景下的多种创新课堂的实践与教学新模式的探索是我国高等教育的一个重要改革和研究方向,论文在“电力系统自动化”课程中引入互联网和对分课堂的创新教学模式,通过教学实践提高了教学质量,并达到良好的教学效果。

全分相无功补偿的策略研究与示范应用

随着电力系统对电能质量的要求越来越高,通过无功功率补偿可以提高电网功率因数、降低线路损耗、改善电压质量,因此对无功补偿装置的经济性、可靠性和精准性提出了更高要求。文章提出的“全分相无功补偿装置”开创性应用智能判据融合控制系统,创新采用了“124888”编码控制逻辑,实现“31档”全分相自动补偿,在补偿方式上能对每一相进行单独补偿,从而达到任一相无功平衡。并通过实例验证该方案的有效性,结果验证了该装置具有响应时间短、补偿精度高的优点。

基于多电源并列运行的输配电网故障诊断的改进方法研究

为有效定位输配电网的故障区段,提升调度应急处置工作的针对性和有效性,在多电源并列运行故障诊断的矩阵算法基础上,提出了基于网络拆分的故障诊断优化方法。通过多重故障场景测试分析,当存在告警信息畸变时,该方法尽管因广度优先搜索分块会浪费一定的时效性,但其容错性好,可有效解决多重故障诊断的问题。