Analysis for Effects of Temperature Rise of PV Modules upon Driving Distance of Vehicle Integrated Photovoltaic Electric Vehicles

The development of vehicle integrated photovoltaics-powered electric vehicles (VIPV-EV) significantly reduces CO2 emissions from the transport sector to realize a decarbonized society. Although long-distance driving of VIPV-EV without electricity charging is expected in sunny regions, driving distance of VIPV-EV is affected by climate conditions such as solar irradiation and temperature rise of PV modules. In this paper, detailed analytical results for effects of climate conditions such as solar irradiation and temperature rise of PV modules upon driving distance of the VIPV-EV were presented by using test data for Toyota Prius and Nissan Van demonstration cars installed with high-efficiency InGaP/GaAs/InGaAs 3-junction solar cell modules with a module efficiency of more than 30%. The temperature rise of some PV modules studied in this study was shown to be expressed by some coefficients related to solar irradiation, wind speed and radiative cooling. The potential of VIPV-EV to be deployed in 10 major cities was also analyzed. Although sunshine cities such as Phoenix show the high reduction ratio of driving range with 17% due to temperature rise of VIPV modules, populous cities such as Tokyo show low reduction ratio of 9%. It was also shown in this paper that the difference between the driving distance of VIPV-EV driving in the morning and the afternoon is due to PV modules’ radiative cooling. In addition, the importance of heat dissipation of PV modules and the development of high-efficiency PV modules with better temperature coefficients was suggested in order to expand driving range of VIPV-EV. The effects of air-conditioner usage and partial shading in addition to the effects of temperature rise of VIPV modules were suggested as the other power losses of VIPV-EV.

Method of Electric Powertrain Matching for Battery-powered Electric Cars

The current match method of electric powertrain still makes use of longitudinal dynamics, which can’t realize maximum capacity for on-board energy storage unit and can’t reach lowest equivalent fuel consumption as well. Another match method focuses on improving available space considering reasonable layout of vehicle to enlarge rated energy capacity for on-board energy storage unit, which can keep the longitudinal dynamics performance almost unchanged but can’t reach lowest fuel consumption. Considering the characteristics of driving motor, method of electric powertrain matching utilizing conventional longitudinal dynamics for driving system and cut-and-try method for energy storage system is proposed for passenger cars converted from traditional ones. Through combining the utilization of vehicle space which contributes to the on-board energy amount, vehicle longitudinal performance requirements, vehicle equivalent fuel consumption level, passive safety requirements and maximum driving range requirement together, a comprehensive optimal match method of electric powertrain for battery-powered electric vehicle is raised. In simulation, the vehicle model and match method is built in Matlab/simulink, and the Environmental Protection Agency (EPA) Urban Dynamometer Driving Schedule (UDDS) is chosen as a test condition. The simulation results show that 2.62% of regenerative energy and 2% of energy storage efficiency are increased relative to the traditional method. The research conclusions provide theoretical and practical solutions for electric powertrain matching for modern battery-powered electric vehicles especially for those converted from traditional ones, and further enhance dynamics of electric vehicles.

Application and Research of High-Power Electric Servo System on Launch Vehicle

The 30 kW high-power electric servo system used in the solid booster of the Long March 6 A(LM-6 A)launch vehicle is introduced,and the function,composition of the system as well as its constituent equipments are detailed.To solve the problem of out-of-tolerance in the system dynamic characteristics,an advanced correction network algorithm architecture and double notch filter were designed.Experimental verification was conducted to prove that the dynamic characteristics requirement under multiple operating conditions could be met.

Analysis and Comparison of Electric Drive System Projects of Military Tracked Vehicles

The electric drive system characteristics of different projects for tracked vehicles are analyzed.For the two most typical projects,the parameters of power,torque and rotating speed and others of drive motor are figured out under the condition of satisfying adequate steering performance of the tracked vehicles.General opinions on the two projects are brought forward and conclusions are drawn.

Analysis of Electrical and Non-electrical Causes of Variable Frequency Drive Failures

VFDs （variable frequency drives） are an integral part of many industrial plants and stations. Reliable operation and maintenance of these drives is vital to ensure sustained plant operation and availability. Understanding of the principles of operation of VFD systems as well as knowledge about their required operating environment is necessary for all operating personnel. Many times the operating personnel do not get involved with different technical issues until a complete failure has occurred. Hence, the awareness of the most dominant failure causes has a significant impact on assisting operators to avoid catastrophic failures and tremendous economic losses due to VFD shutdown. Proper plant design, accurate monitoring and data logging, following manufacturer preventive maintenance schedule, and choosing qualified team of operators can be the key to an efficient operation and a long lifetime for any VFD system. In this paper, we have analyzed the electrical and non-electrical causes of VFD failures based on a case study of a typical medium voltage VFD pumping station. Finally, recommendations are given from field analysis and observations.

Overview of condition monitoring and operation control of electric power conversion systems in direct-drive wind turbines under faults

Electric power conversion system （EPCS）, which consists of a generator and power converter, is one of the most important subsystems in a direct-drive wind turbine （DD-WT）. However, this component accounts for the most failures （approximately 60% of the total number） in the entire DD-WT system according to statistical data. To improve the reliability of EPCSs and reduce the operation and maintenance cost of DD-WTs, numerous researchers have studied condition monitoring （CM） and fault diagnostics （FD）. Numerous CM and FD techniques, which have respective advantages and disadvantages, have emerged. This paper provides an overview of the CM, FD, and operation control of EPCSs in DD-WTs under faults. After introducing the functional principle and structure of EPCS, this survey discusses the common failures in wind generators and power converters; briefly reviewed CM and FD methods and operation control of these generators and power converters under faults; and discussed the grid voltage faults related to EPCSs in DD-WTs. These theories and their related technical concepts are systematically discussed. Finally, predicted development trends are presented. The paper provides a valuable reference for developing service quality evaluation methods and fault operation control systems to achieve high-performance and high-intelligence DD-WTs.

电动汽车用多相电驱重构型车载充电系统关键技术综述

电驱重构型车载充电系统为电动汽车电气部分提供了一种全新轻量化设计思路,旨在利用电驱单元分时执行电驱与充电2种变流功能。相较于三相电驱系统,多相电驱系统具有输出转矩平滑、容错性能强等诸多优势特性。鉴于此,该文首先归纳现有并网式多相电驱重构型车载充电系统的拓扑结构与控制策略,并介绍其容错运行方案;然后,着重分析太阳能电动汽车用多能量端口电驱重构型车载充电系统的工作原理与控制策略;最后,总结全文并对多相电驱重构型车载充电系统的发展方向进行展望。

某纯电驱动重载车辆能耗预测模型

高精度能耗预测模型是准确预测车辆续驶里程的重要前提。针对载荷大幅度变化且非结构化道路运行的纯电驱动重载车辆,建立其组合能耗模型,该模型由能耗计算基本模型与长短时记忆(Long Short-Term Memory,LSTM)神经网络差值修正两部分组成。基于能量流动过程驱动电机和变速器效率建模,结合汽车行驶动力学建立能耗计算基本模型;采用LSTM神经网络来修正基本模型能耗预测结果与车辆典型工况功率测试值的差值,有效提高了大幅变载荷且低信噪比坡度环境下的车辆能耗预测精度,因此组合能耗模型具有参数简单和模型拟合不需解释能耗规律的优点。经试验测试分析,与VT-Micro能耗模型和径向基(Radial Basis Function,RBF)神经网络能耗模型相比,所提组合能耗模型的功率预测平均误差率分别降低了17.76%和3.35%,能够实现纯电驱动重载车辆复杂工况下能耗的准确实时预测。

飞机电推进系统高效能电机及其驱动控制技术

飞机动力系统的电气化是继机载二次能源逐步统一为电能之后航空电气化发展的重要方向和高级阶段,能够大幅提升飞机动力系统能量利用效率,是航空业绿色发展的重要途径。电机系统是飞机电推进系统的核心机电能量变换环节,高效能电机、电力电子变换及其驱动控制技术是电推进飞机发展的基础支撑。该文从电推进飞机动力系统架构出发,分析电推进飞机电机系统的特征与要求。总结永磁同步电机、异步电机、电励磁无刷同步电机和超导电机4种类型电机在电推进飞机上的研究和应用现状,系统讨论电推进系统中不同类型电机和电机驱动器的关键技术。最后,展望新材料、新器件、新工艺、人工智能和综合热管理等技术对电推进飞机电机及其驱动控制技术发展的推动作用。

电动智能农业车辆开发技术与现状

为提高从业人员对电动智能化农业车辆现阶段技术状况的认知水平,本文从电动化、智能化两个方向进行调研、分析了电动智能农业车辆在电驱动、动力电池、智能网联等技术方面的国内外发展概况。经过对大量文献进行分析,中国电动智能化农业车辆存在起步晚、技术落后、产业化程度滞后等问题,中国在电驱动技术、电池技术、网联化技术等方面还有较大的研发空间。

Development of electric construction machinery in China:a review of key technologies and future directions

The issues of energy shortage and environmental pollution have accelerated the electrification of construction ma-chinery(CM)industry globally.In China,the amount of electric construction machinery(ECM)has been growing across the industry.The sales of ECM are estimated to reach 600000 vehicles by the end of 2025,while the total demand for battery power will reach 60 GWh.However,the development of ECM still faces critical challenges including reliable power supply and energy distribution among various components.In this review,we primarily focus on important technological breakthroughs and the difficulties faced by the CM industry in China.An overview of ECM including classification and characteristics is given at the beginning.Next,the selection of key components such as the electric motor and the energy storage units,and the control strategy in the pure electric drive system are discussed.The characteristics of the hybrid electric drive system such as structure design and power matching are analyzed in detail.The battery management system(BMS)is critical to ensure appropriate battery health for reliable power supply.Here,we extensively review technical developments in various BMSs.In addition,we roughly estimate the national total of CM emissions and the potential environmental benefits of employing ECMs in China.Finally,we set out future research directions and industrial development of ECM.

Online power management strategy for plug-in hybrid electric vehicles based on deep reinforcement learning and driving cycle reconstruction

This paper proposes a novel power management strategy for plug-in hybrid electric vehicles based on deep reinforcement learning algorithm.Three parallel soft actor-critic(SAC)networks are trained for high speed,medium speed,and low-speed conditions respectively;the reward function is designed as minimizing the cost of energy cost and battery aging.During operation,the driving condition is recognized at each moment for the algorithm invoking based on the learning vector quantization(LVQ)neural network.On top of that,a driving cycle reconstruction algorithm is proposed.The historical speed segments that were recorded during the operation are reconstructed into the three categories of high speed,medium speed,and low speed,based on which the algorithms are online updated.The SAC-based control strategy is evaluated based on the standard driving cycles and Shenyang practical data.The results indicate the presented method can obtain the effect close to dynamic programming and can be further improved by up to 6.38%after the online update for uncertain driving conditions.

设施园艺移动平台分布式驱动自适应防滑控制

针对设施园艺特殊作业场景对电驱移动平台灵活作业与高操纵稳定性需求,该研究设计了一种四轮轮毂电机独立驱动的分布式设施园艺电驱移动平台,并提出了一种可提高转向灵活性与稳定性的自适应防滑控制策略。在该控制策略中,首先构建电驱移动平台动力学模型与Ackermann差速转向模型,结合速度瞬心原理及轮胎侧偏角确定各车轮转向目标转速;其次,为提高电驱移动平台对时变附着系数的适应能力,采用改进的强跟踪自适应无迹卡尔曼滤波算法设计复杂路面识别器,实现对路面附着系数准确估计;最后,设计基于自适应滑模算法的防滑控制器,根据路面附着系数估计值确定车轮相对最佳滑转率并实时控制滑转率。为验证所提控制策略的有效性,开展了Carsim-MATLAB/Simulink联合仿真与分布式设施园艺电驱移动平台实车试验。试验结果表明,所提控制策略可准确估计复杂道路下路面附着系数,降低车轮滑转率误差;在不变路面、对接路面与对开路面3种工况下,左侧车轮滑转率误差分别为0.031、0.015和0.038,右侧车轮滑转率误差分别为0.026、0.005和0.028;在不变路面与随机路面实测路况下,电驱移动平台路面附着系分别数约为0.44和0.47,最大滑转率分别约为0.69和0.68,有效抑制了轮胎转向时的过度滑转,提高了电驱移动平台的行驶稳定性。研究可为设施园艺车辆驱动防滑控制提供具体理论依据和实施方案。

基于VR和AR的《电机与拖动》立体化教材探索

“电机与拖动”是一门重要的专业基础课程,该课程对于学生工程师素质的培养有着非常重要的作用。由于电机结构复杂,现有教材较难准确描述。因此,利用虚拟仿真和增强现实技术,面向课程教学中的难点,对教材内容进行了重新梳理,引入了电机实际应用,配套了Matlab仿真程序,开发了计算机端虚拟仿真VR教学软件和手机APP三维互动AR软件,打造了多种形式于一体的立体化教材。

新能源电动农机一源多用创新供能赋能农网农机融合发展——基于全国536份调查问卷分析

随着我国“三电”技术的快速发展,新能源电动农机也如雨后春笋般迅速崛起,一源多用的提出是解决新能源电动农机季节性闲置、利用率低、无法与农村电网(以下简称农网)新型电力系统互动融合等问题的创新发展模式,具有用能清洁环保、数智化程度高、易于组网的现代化技术特征。针对新能源电动农机一源多用的关键技术、应用场景、实施路径和商业模式等存在问题与发展前景,面向农机、农业、电力和电网等相关从业人员开展网络问卷调研,从一源多用技术发展潜力和农网农机融合认知态势等视角,基于调研结果,研究了一源多用赋能农网农机融合的农机电能替代潜力、应用场景、综合效益等,分析了一源多用的实施路径和商业模式,提出了一源多用创新供能模式赋能农网农机融合的关键技术和扶持政策建议。结果表明,新能源电动农机一源多用发展模式具有较好经济效益和环保效益,发展前景被普遍看好,对落实双碳目标与乡村振兴战略具有积极意义。未来仍需开展新能源电动农机和电网融合互动关键技术协同攻关和应用研究,探索可持续且多方共赢的良性商业模式。

页岩油电驱设备面临的供电问题及解决策略

国内某页岩油示范区已进入规模开发阶段,对钻机和压裂机组的需求量较大,目前面临用电难、电驱钻井和压裂作业难以开展的问题。通过对电动钻机和电驱压裂机组的用电需求分析,单部电动钻机需要的供电容量达3710 kVA;单套电驱压裂机组需要的供电容量达38061 kVA。结合区域已建电力系统现状,指出现阶段示范区电力系统的供电能力严重不足,供电容量只能以满足机采设备和站场设备用电为主,也可兼顾部分电动钻机用电,但是与电驱压裂用电需求的容量相差甚远。对电网而言,电动钻机和电驱压裂机组均属电能质量干扰源,设备接入系统会明显影响供电质量和电网安全稳定运行。此外,施工供电设备多次接入电网或从电网脱离,也会增加调度管理难度。为了改变这种不利局面,提出两种供电问题解决策略:一是积极促进电网增容和升级,改善供电条件,为现场扩大电气化施工作业规模奠定基础;二是利用页岩油伴生气量较大的优势,建设燃气发电站和配电网,缓解电网供电压力。建议策略一优先采用,策略二可作为策略一的有益补充。

边缘计算下的电力变压器热稳定控制方法

为解决因电力变压器热稳定控制误差高、控制响应时间长的问题,提出一种基于边缘计算的热稳定控制方法。该方法引入边缘计算,将设备标准状态值设为边缘点值,估计电力变压器热稳定状态,以此估计值为基础,通过潮流计算获取温度变化影响值,结合温度变化影响值和热稳定状态估计,计算热稳定控制系数,设定热稳定控制阈值,通过阈值对比,完成电力变压器热稳定控制。实验结果表明,所提方法的热稳定控制误差和控制响应时间均较低,其具备了一定的可行性和有效性。

气浮电动缸功率匹配分析与控制算法设计

针对承担重载的电驱机构存在运行功率大、机械结构易磨损等问题,论文介绍了一种气浮电动的联合驱动方案,首先分析了气浮电动缸的工作原理及电、气驱动力和功率匹配情况,然后把电动系统功率作为预测变量,以降低电动系统功率为目的,设计了气动系统模型预测控制(MPC)算法。仿真结果显示,应用MPC算法后的气动系统分担了较大驱动力,降低电动系统功率效果显著。

基于正弦函数的自动驾驶电动汽车换道控制系统设计

由于交通道路环境具有不确定性,为实现对换道行为的有效控制,对基于正弦函数的自动驾驶电动汽车换道控制系统进行了研究;利用正弦型三相逆变控制电源输入的电力信号,驱动换道模拟平台与换道信息通信编码器,完成自动驾驶电动汽车换道控制系统的各级应用部件设计;筛选出关键的换道片段,在此基础上,提取始末换道位置,构建车道中心线势场,定义具体的换道轨迹簇,生成控制所需的电动汽车换道轨迹簇;根据安全换道车距的正弦函数计算结果,搭建反馈控制器闭环,并利用该模型实施对换道轨迹的控制与规划,实现基于正弦函数的汽车换道行为控制,联合各级应用结构,完成自动驾驶电动汽车换道控制系统的设计;实验结果表明,上述系统不会因不及时换道导致自动驾驶电动汽车的行车碰撞问题,且能够准确识别道路中的障碍物,提升行车安全;该系统的设计和实现为自动驾驶电动汽车的发展和应用提供了有益的参考和启示。

多电飞机中高效高功率密度伺服控制器设计

高效、高功率密度和高功重比是飞机电力作动系统伺服控制器的发展趋势。分析了限制伺服控制器功率密度提升的关键因素,从功率器件、母线电容和机械结构展开研究。采用分立SiC器件多管并联方案,通过权衡效率和功率密度设计功率器件的并联数量;建立电容电流应力、电压纹波与电容的数学关系,给出了最小体积的电容设计方案;采用立体式板卡和双面贴装散热设计了紧凑型机械结构来提升功率密度。最后设计出功率50 kW、功率密度11 kW/L的样机。