Decentralised online charging scheduling for large populations of electric vehicles: a cyber-physical system approach

As the number of electric vehicles (EVs) grows, their electricity demands may have significant detrimental impacts on electric power grid when not scheduled properly. In this paper, we model an EV charging system as a cyber-physical system, and design a decentralised online EV charging scheduling algorithm for large populations of EVs, where the EVs can be highly heterogeneous and may join the charging system dynamically. The algorithm couples a clustering-based strategy that dynamically classifies heterogeneous EVs into multiple groups and a sliding-window iterative approach that schedules the charging demand for the EVs in each group in real time. Extensive simulation results demonstrate that our approach provides near-optimal solutions at significantly reduced complexity and communication overhead. It flattens the aggregated load on the power grid and reduces the costs of both the users and the utility.     

电动汽车充电口的超声位姿测量系统设计

针对电动汽车充电口视觉定位系统存在的配置成本高、图像处理算法复杂、环境适应性差等问题,提出了一种基于超声波测距的充电口位姿测量系统。首先对基于超声波的充电口位姿的测量技术进行了研究,然后对充电口的超声位姿重构进行了分析,采用了多点位超声融合的关键技术,最终实现了电动汽车充电口位姿的测量。实验结果表明测距模块在300~1200mm范围内测距精度可达±0.2959mm,位姿测量系统定位精度可达±1.5mm、±2.4°。经实际应用发现该系统具有较强的鲁棒性,达到了传统视觉定位装置的效果,满足了电动汽车充电口位姿测量的工程需求。     

电动汽车的充电模式及充电设施建设运营模式研究

电动汽车是节能、环保和低碳经济的发展需求,而电动汽车电池既是发展电动汽车的核心,更是电力工业与汽车行业的关键结合点。在政府对电动汽车产业的大力推动下,我国电动汽车产业将步入快速发展期,这也极大地推动了电动汽车充电站和充电桩的建设,大量电动汽车的充电行为将会给电网带来较大影响。电动汽车的普及程度、类型、充电时间、充电方式以及充电特性的不同会使电动汽车对电网的影响发生变化。介绍了世界范围内电动汽车电池的四种充电模式：换电模式,有线慢充,有线快冲,无线充电。这四种充电模式目前处在不同的发展阶段,面临不同的问题,并各自具有不同的发展策略。对目前已经形成的电动汽车制造厂商主导模式、电网企业主导模式和第三方建设运营企业主导模式,进行分析研究和比较     

A distributed charging strategy based on day ahead price model for PV-powered electric vehicle charging station

This paper studies a distributed charging model based on day-ahead optimal internal price for PV-powered Electric Vehicle (EV) Charging Station (PVCS). Considering the feed-in-tariff of PV energy, the price of utility grid and the forecast model of PV based on back-propagation neural network (BPNN), a system operation model of PVCS is introduced, which consists of the profit model of PVCS operator (PO) and the cost model of EV users. The model proposed in this paper can be designed as a Stackelberg game model, where the PO acts as the leader and all EV users participated are regarded as the followers. An optimization strategy based on heuristic algorithm and nonlinear constrained programming are adopted by the PO and each EV user, respectively. Moreover, a real-time billing strategy is proposed to deal with the errors from the forecasted PV energy and the expected charging arrangements. Finally, through a practical case, the validity of the model is verified in terms of increasing operation profit and reducing charging cost.     

基于二次聚类的大规模电动汽车有序充电调度策略优化

针对大量电动汽车无序充电造成的充电站利用率不均衡问题,提出一种大规模电动汽车有序充电调度策略。首先,以电动汽车充电需求的位置为聚类指标,借助归一化相似度进行层次聚类和基于K-means算法的二次划分,以实现属性相似的电动汽车的汇聚。进一步地,通过Dijkstra算法获取电动汽车到达各个充电站的最优路径,以充电站内电动汽车的均匀分配和电动汽车充电路程最短作为目标函数,构建了基于电动汽车聚类的充电调度模型,通过遗传算法求取最优解。与未进行电动汽车聚类的充电调度策略进行的仿真对比实验结果表明,在车辆较多时所提方法的计算时间可减少一半以上,具有较高的实用性。     

负载影响下纯电动汽车配送路径规划及充电策略

由于纯电动汽车行驶里程的限制，在满足商用要求的前提下，纯电动汽车用于长途运输服务在短期内难以实现。不过，城市物流因其配送区域较小、货物的批量较小、批次较多的特点，可以考虑使用纯电动汽车来完成城市的配送任务。为满足车辆当天多次配送任务的要求以及考虑车辆负载对实时能耗的具体影响，建立了考虑车辆负载对实时能耗影响的配送模型，以及时满足客户的服务时间要求。并以城市A为例，设计了蚁群算法对模型进行求解，为纯电动汽车的配送任务进行合理的路径规划与充电策略的安排。最后，通过与使用燃油车辆运营相比较，分析未来纯电动汽车在城市配送物流中的可行性。     

共享充电桩下负荷时间分布均衡的小区电动汽车充电方案优化

针对电动汽车充电负荷增加、电网安全性降低,以及停车困难小区只能使用共享充电桩等问题,提出了一种充电桩选择与电动汽车充电优化的组合模型。该模型以共享充电桩之间充电时间标准差和全天充电负荷标准差之和最小为目标。考虑到电动汽车充电桩分配方案以及电动汽车充电方案两者的重要程度并不相同,提出了一种随着迭代次数的增加,变化概率不断改变的动态概率遗传算法。将改进后的遗传算法求解该模型,通过求解一个算例,进一步阐述所提算法的原理和过程,验证了该算法的可行性和有效性。     

负载影响下纯电动汽车配送路径规划及充电策略

由于纯电动汽车行驶里程的限制,在满足商用要求的前提下,纯电动汽车用于长途运输服务在短期内难以实现。不过,城市物流因其配送区域较小、货物的批量较小、批次较多的特点,可以考虑使用纯电动汽车来完成城市的配送任务。为满足车辆当天多次配送任务的要求以及考虑车辆负载对实时能耗的具体影响,建立了考虑车辆负载对实时能耗影响的配送模型,以及时满足客户的服务时间要求。并以城市A为例,设计了蚁群算法对模型进行求解,为纯电动汽车的配送任务进行合理的路径规划与充电策略的安排。最后,通过与使用燃油车辆运营相比较,分析未来纯电动汽车在城市配送物流中的可行性。     

Electric vehicles charging control in a smart grid: A model predictive control approach

The paper presents an event driven model predictive control (MPC) framework for managing charging operations of electric vehicles (EV) in a smart grid. The objective is to minimize the cost of energy consumption, while respecting EV drivers' preferences, technical bounds on the control action (in compliance with the IEC 61851 standard) and both market and grid constraints (by seeking the tracking of a reference load profile defined by the grid operator). The proposed control approach allows “flexible” EV users to participate in demand side management (DSM) programs, which will play a crucial role in improving stability and efficiency of future smart grids. Further, the natural MPC formulation of the problem can be recast into a mixed integer linear programming problem, suitable for implementation on a calculator. Simulation results are provided and discussed in detail.     

Integrated stability and traction control for electric vehicles using model predictive control

In this paper, an integrated vehicle and wheel stability control is developed and experimentally evaluated. The integrated structure provides a more accurate solution as the output of the stability controller is not altered by a separate unit, therefore its optimality is not compromised. Model predictive control is used to find the optimal control actions. The proposed control scheme can be applied to a wide variety of vehicle driveline and actuation configurations such as: four, front and rear wheel drive systems. Computer simulations as well as experiments are provided to show the effectiveness of the proposed control algorithm.     

基于ARM的电动汽车车载智能充电系统的研制

电动汽车以其高效率、低排放、多能源的特点有效地抑制了能源紧张和环境污染问题,但高效可靠的充电系统和车载能源问题成为其发展的主要瓶颈。对此,以ARM处理器为整个充电系统的控制核心,并结合嵌入式操作系统研制了一种车载智能充电系统。构建了嵌入式系统软硬件平台,详细阐述了车载智能充电系统的设计过程。理论和实验分析表明,该充电系统减少了电动汽车充电时间,性能优良、可靠性高。     

A predictive discrete event approach for the optimal charging of electric vehicles in microgrids

Distributed generation, renewables (RES), electric vehicles (EVs), storage systems and microgrids are increasing widespread all over the world owing to the necessity of applying policies for sustainable development. In particular, the progressive shift from traditional vehicles to EVs is considered as one of the key measures to achieve the objective of a significant reduction in the emission of pollutants, especially in urban areas. One of the major problem to be solved to make EVs a viable solution for the sustainable mobility is the development of effective facilities for vehicles. In this context, besides to technological aspects, one of the most important issues is the definition of fair and efficient policies for the sequencing and scheduling of the vehicle charging. In fact, scheduling problems are widely recognized as representing one of the most challenging class of optimization problems. Besides, the additional presence of specific features concerning vehicle charging systems (like controllable execution times, presence of intermittent energy sources, etc.) make even more difficult the vehicle charging problem. In this framework, despite the fact that optimization problems regarding energy systems are generally considered within a discrete-time setting, in this paper a discrete event approach is proposed. The reasons for this choice are essentially two. The first one is the necessity of containing the number of the decision variables, which grows beyond reasonable values when a small-time discretization step is chosen. The second is the impossibility of an accurate tracking of process and events using a discrete-time approach.The considered optimization problem regards the charging of a series of vehicles by a charging station that is integrated in a microgrid. Such a microgrid includes also renewable and traditional energy sources, storage systems and a local load. The objective function to be minimized results from the weighted sum of the (net) cost for purchasing energy from the external grid, the cost related to the use of fossil fuels, and the overall tardiness of the services provided to the customers. The effectiveness of the proposed approach is tested on a real case study.     

Fault-tolerant traction control of electric vehicles

This paper investigates a new traction control approach that requires neither chassis velocity nor information about tire-road conditions. Plant fault subject to the uncertainties of the mathematical model and slightly sensor fault are concerned. For general traction control of vehicles, the variation of model behavior may break down the steering stability if the chassis velocity is not monitored. This paper presents a fault-tolerant approach based on the maximum transmissible torque estimation (MTTE) scheme which has the ability to prevent electric vehicles from skidding. A PI-type disturbance observer is employed to enhance the steering stability of the MTTE approach. This proposed approach does not require both the differentiator and the inversion of the controlled plant. Finally, illustrated examples are given for evaluating the fault-tolerant performance and feasibility of the presented anti-slip strategy.     

基于GPU并行计算的电动出租车新建充电站选址模型

针对电动出租车充电站优化选址问题，构建了以未满足的电动出租车充电需求量和新建充电站的固定成本最小为目标函数的电动出租车新建充电站选址模型，并提出基于改进的多目标粒子群算法的模型求解方法。为解决未满足充电需求量计算的性能瓶颈问题，设计了一个基于图形处理器（GPU）的未满足充电需求量并行计算算法，并通过实验验证其运行时间约为基于CPU串行算法运行时间的10%~12%。以北京为例，收集、处理相关多源数据，对提出的选址模型进行了应用示例分析，表明所提出的充电站优化选址方案具有可行性。     

Locating electric vehicle charging stations with service capacity using the improved whale optimization algorithm

This study proposes an Improved Whale Optimization Algorithm (IWOA) that, on the basis of Whale Optimization Algorithm (WOA) designed by Mirjalili and Lewis (2016), introduces Gaussian mutation operator, differential evolution operator, and crowding degree factor to the algorithm framework. Test results with nine classic examples show that IWOA significantly improves WOA’s precision and computing speed. We also model the locating problem of Electric Vehicle (EV) charging stations with service risk constraints and apply IWOA to solve it. This paper introduces service risk factors, which include the risk of service capacity and user anxiety, establishing the EV charging station site selection model considering service risk. Computational results based on a large-scale problem instance suggest that both the model and the algorithm are effective to apply in practical locating planning projects and help reduce social costs.     

基于单亲遗传算法混合动态规划的电动汽车充电调度优化策略

充电调度是电动汽车运营的一个重要内容,合理有效的充电策略在帮助运营商降低成本的同时还能减轻电网高峰时段的供电负担。从充电站运营商的角度出发,在实时电价和每个充电任务时间必须连续的假设下,建立了一个电动汽车充电成本最小模型,给出一个单亲遗传算法混合动态规划的两阶段常规充电调度算法。与电桩一旦闲置即刻分配车辆进行充电的策略以及传统单亲遗传算法相比较,该充电调度策略在电桩负载均衡的情况下有效降低了电费成本,说明了算法的有效性。此外,实验结果表现出了充电任务在多数相同时段聚集从而避开高电价时段的特征,说明充电策略对减轻高峰时段的电网压力也有一定帮助。     

含电动汽车充电站的多端直流微电网研究

为未来大规模能源互联网的形成以及多种新能源的接入提供技术支撑,设计直流微电网的拓扑结构,提出了一种四端口环网的直流电网拓扑结构,实现交流电网、储能单元、直流负荷、风力发电和光伏发电与直流电网的互联。首先研究了交流电网与直流电网的接口方式和相关技术参数,提出了光伏发电、风力发电和储能单元等接口的技术配置。其次,研究了整个直流微电网的启停时序,设计了直流电网的接线方式、电压等级和容量,最后基于MATLAB Simulink平台搭建了直流园区系统仿真模型,然后对典型工况进行了仿真分析：（1）储能单元由放电到能量为零;（2）储能单元由充电到能量充满;（3）VSC1变换器功率反转;（4）负荷跳变;（5）储能单元由放电到充电。这些工况基本包涵了直流微电网可能出现的运行状态,对直流微电网的运行管理有较高的参考价值。     

Socio-technical smart grid optimization via decentralized charge control of electric vehicles

The penetration of electric vehicles becomes a catalyst for the sustainability of Smart Cities. However, unregulated battery charging remains a challenge causing high energy costs, power peaks or even blackouts. This paper studies this challenge from a socio-technical perspective: social dynamics such as the participation in demand-response programs, the discomfort experienced by alternative suggested vehicle usage times and even the fairness in terms of how equally discomfort is experienced among the population are highly intertwined with Smart Grid reliability. To address challenges of such a socio-technical nature, this paper introduces a fully decentralized and participatory learning mechanism for privacy-preserving coordinated charging control of electric vehicles that regulates three Smart Grid socio-technical aspects: (i) reliability, (ii) discomfort and (iii) fairness. In contrast to related work, a novel autonomous software agent exclusively uses local knowledge to generate energy demand plans for its vehicle that encode different battery charging regimes. Agents interact to learn and make collective decisions of which plan to execute so that power peaks and energy cost are reduced system-wide. Evaluation with real-world data confirms the improvement of drivers’ comfort and fairness using the proposed planning method, while this improvement is assessed in terms of reliability and cost reduction under a varying number of participating vehicles. These findings have a significant relevance and impact for power utilities and system operator on designing more reliable and socially responsible Smart Grids with high penetration of electric vehicles.     

电动车制动防抱死控制系统

为了改善电动车的可操作性和稳定性,对电动车制动防抱死控制系统进行了研究.基于电动机与车轮胎直接相连的结构,设计控制器以期得到满意的控制性能.首先提出一种基于模糊控制器和PID算法的制动防抱死控制系统;而后针对汽车纵向四轮模型,设计了模糊PID算法;最后通过试验结果证明了该控制算法的有效性.尽管道路条件的变化不同,电动车制动防抱死控制系统表现了满意的控制性能.     

电动汽车充放电机变换器解耦控制系统设计

充放电机变换器是实现网侧电能和蓄电池储能交换的关键装置,同时可以消除谐波、实现单位功率因数运行,是一个多输入、多输出的非线性系统。在同步旋转坐标系中,三相电压型PWM变换器的d、q轴电流之间存在耦合,导致有功电流和无功电流不能独立控制。采用交叉解耦控制虽可以获得较好的稳态性能,但暂态性能较差,影响充放电机的工作性能。所采用的状态反馈解耦控制策略电流超调量小,调节时间短,非常适用于充放电机的变换器。仿真实验验证了控制策略的可行性和有效性。