Charging Coordination Research Articles

A Multiagent Federated Reinforcement Learning Approach for Plug-In Electric Vehicle Fleet Charging Coordination in a Residential Community

The increasing penetration of distributed renewable energy and electric vehicles (EV) in local microgrids/residential-community has brought a great challenge to balancing system stability and economic benefits. This paper proposes a decentralized framework based on an efficient federated deep reinforcement learning method for plug-in electric vehicle (PEV) fleet charging management in a residential community, which is equipped with a photovoltaic and battery energy storage system and connected to a local transformer. Firstly, the framework of PEV charging management is described as a virtual EV charging station coordinating charging tasks through sharing public information with distributed agents. Then, an individual preference model of PEV is developed considering heterogenous PEV charging anxiety, battery degradation, and collective penalty. Subsequently, we propose an attention-weighted federated soft-actor-critic method to efficiently seek the co-ordinational scheduling of the PEV fleet charging in a distributed way, where scalability and privacy protection can be ensured with attention-based information sharing. Finally, a real-world case study is conducted to validate the effectiveness and feasibility of the proposed approach.

Emission mitigation potential from coordinated charging schemes for future private electric vehicles

Plug-in electric vehicles (EVs) are expected to synergize with low or even zero-carbon electricity towards a deep mitigation of greenhouse gas (GHG) emission and ultimately carbon neutrality. These benefits are only obtainable when EV charging maximizes the consumption of electricity generated from renewable energy sources. However, the current mismatch between renewable energy output and EV charging demand poses a substantial challenge. Rescheduling charging events, namely charging coordination, has the potential to integrate renewable electricity and tap into higher GHG emission reductions. In this study, with Beijing as the research domain, we develop a charging demand model informed by real-world usage data generated by a massive fleet of private cars, and evaluate the comprehensive impacts of various charging coordination schemes in the future with higher adoption rates of both private EVs and renewable power sources. The research finds that strategies aiming at maximizing renewable power consumption, netload valley filling, and charging cost minimization have similar climate benefits, which can reduce well-to-wheels GHG emissions by approximately 20%, cut charging cost by half, and erase 95% of the need for newly installed generation capacity compared to the benchmark scenario without coordinated charging. On the other hand, conventional charging strategies, such as the simple demand-valley-filling strategy, would increase GHG emissions. The study indicates that substantial benefits can be synergistically achieved between power and transport systems towards improved grid stability, lower fuel cost, and greater emission mitigation by leveraging EV charging flexibility at the end-user side (i.e., charging facility). Furthermore, the potential need for sophisticated charging coordination with multiple optimization objectives is brought to attention.

The SOC Based Dynamic Charging Coordination of EVs in the PV-Penetrated Distribution Network Using Real-World Data

A successful distribution network can continue to operate despite the uncertainties at the charging station, with appropriate equipment retrofits and upgrades. However, these new investments in the grid can become complex in terms of time and space. In this paper, we propose a dynamic charge coordination (DCC) method based on the battery state of charge (SOC) of electric vehicles (EVs) in line with this purpose. The collective uncoordinated charging profiles of EVs charged at maximum power were investigated based on statistical data for distances of EVs and a real dataset for charging characteristics in the existing grid infrastructure. The proposed strategy was investigated using the modified Roy Billinton Test System (RBTS) performed by DIgSILENT Powerfactory simulation software for a total 50 EVs in 30 different models. Then, the load balancing situations were analyzed with the integration of the photovoltaic (PV) generation and battery energy storage system (BESS) into the bus bars where the EVs were fed into the grid. According to the simulation results, the proposed method dramatically reduces the effects on the grid compared to the uncoordinated charging method. Furthermore, the integration of PV and BESS system, load balancing for EVs was successfully achieved with the proposed approach.

Metal-Ion-Cross-Linked Nitrogen-Doped Carbon Dot Hydrogels for Dual-Spectral Detection and Extractable Removal of Divalent Heavy Metal Ions

Nitrogen-doped carbon dots (NCDs) synthesized by the low-temperature sintering method show electronegativity rich in −COO–, −CO–NH–, −NH–, and −OH. The structure, morphology, and fluorescence performance of NCDs were successively characterized by Fourier-transform, infrared, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, photoluminescence, ultraviolet (UV), and X-ray fluorescence analyses. On the one hand, NCDs can sensitively detect Pb2+ in water with a detection limit of 3 ppb through the dual response of fluorescence emission spectra and UV absorbance spectra. On the other hand, the negatively charged NCDs combine with various positively charged heavy metal ions (Pb2+, Cu2+, Ni2+, Co2+, and Cd2+) through charge attraction and coordination to form a hydrogel, thereby removing heavy metal ions from the water. Among them, the removal rate of Pb2+ by NCDs is as high as 94.8%. It is the first time that pure NCDs have been used to remove heavy metal ions quickly and easily in the form of a reversible hydrogel. A simple way is to achieve ultrasensitive detection and high-efficiency removal of heavy metal ions in water with unitary NCDs.

A Two-Level Desired Load Profile Tracking Algorithm for Electric Two-Wheeler Charging Stations

In Vietnam and in other developing countries, two-wheeled electric vehicles are potential alternatives to gasoline-powered motorbikes. The growth in the number of Electric Two-Wheelers (E2Ws) requires a large power demand of charging load. In addition, the increasing spread in the appearance and penetration of rooftop photovoltaic (PV) power systems, with their intermittence and uncertain nature, poses technical challenges that need to be addressed. The coordination of PV rooftop operation and EV charging may be an effective solution to meet the emerging load demand from EVs, increasing solar power penetration while minimizing the cost of grid reinforcement or possible upgrades. In this paper, a two-level desired load profile tracking algorithm for PV integrated electric bicycles/electric motorcycle charging stations is proposed with the purposes of load leveling, valley filling, and peak shaving. The simulation results show that the proposed algorithm is an effective solution, significantly improving the load profile, especially when compared with uncontrolled charging and constant charging power scheme.

Creating Dynamic Nanospaces in Solution by Cationic Cages as Multirole Catalytic Platform for Unconventional C(sp)−H Activation Beyond Enzyme Mimics

AbstractHerein we demonstrate that, based on the creation of dynamic nanospaces in solution by highly charged positive coordination cage of [Pd6(RuL3)8]28+, multirole and multi‐way cage‐confined catalysis is accomplishable for versatile functions and anomalous reactivities with the aid of the biomimetic cage effect. The high cationic‐host charges drive partial deprotonation of 24 imidazole‐NHs on cage sphere alike imidazole‐residuals in proteins, generating amphoteric heterogeneity in solution to enforce effective cavity‐basicity against solution‐acidity. Synergistic actions arisen from cage hydrophobicity, host‐guest electrostatic interactions and imidazole‐N coordination facilitate C(sp)−H activation and carbanionic intermediate stabilization of terminal alkynes to achieve unusual H/D‐exchange and Glaser coupling under acidic conditions, and enable phase transfers of water‐insoluble substrates/products/co‐catalysts to make immiscible‐phase and bi‐phase catalysis feasible, thus providing a useful catalytic protocol to combine merits from homogeneous, heterogeneous, enzymatic and phase transfer catalysis.

Creating Dynamic Nanospaces in Solution by Cationic Cages as Multirole Catalytic Platform for Unconventional C(sp)-H Activation Beyond Enzyme Mimics.

Herein we demonstrate that, based on the creation of dynamic nanospaces in solution by highly charged positive coordination cage of [Pd6 (RuL3 )8 ]28+ , multirole and multi-way cage-confined catalysis is accomplishable for versatile functions and anomalous reactivities with the aid of the biomimetic cage effect. The high cationic-host charges drive partial deprotonation of 24 imidazole-NHs on cage sphere alike imidazole-residuals in proteins, generating amphoteric heterogeneity in solution to enforce effective cavity-basicity against solution-acidity. Synergistic actions arisen from cage hydrophobicity, host-guest electrostatic interactions and imidazole-N coordination facilitate C(sp)-H activation and carbanionic intermediate stabilization of terminal alkynes to achieve unusual H/D-exchange and Glaser coupling under acidic conditions, and enable phase transfers of water-insoluble substrates/products/co-catalysts to make immiscible-phase and bi-phase catalysis feasible, thus providing a useful catalytic protocol to combine merits from homogeneous, heterogeneous, enzymatic and phase transfer catalysis.

Organic-Inorganic Hybrid Luminescent Hydrogel Glued by a Cationic Polymeric Binder.

Luminescent hydrogels have shown great potential in many fields, such as lighting, display, imaging, and sensing, because of their unique optical properties, biocompatibility, and easy processing. Organic-inorganic hybrid self-assembly can not only enhance the hydrogels' mechanical strength, but also retain their self-healing ability. Herein, a luminescent supramolecular hydrogel is reported, which is formed via self-assembly of the negatively charged Laponite nanosheets and cationic lanthanide coordination polymer. The corresponding results reveal that the multiple binding interaction between Laponite and the polymeric binder is vital for improving the mechanical performance of the obtained luminescent supramolecular hydrogel.

Authentication and Billing for Dynamic Wireless EV Charging in an Internet of Electric Vehicles

Dynamic wireless charging (DWC) is a promising technology to charge Electric Vehicles (EV) using on-road charging segments (CS), also known as DWC pads. In order to ensure effective utilization of this on-the-road charging service, communication and coordination need to be established between the EVs and the different network entities, thereby forming an Internet of Electric Vehicles (IoEV). In an IoEV, EVs can utilize different V2X communication modes to enable charging scheduling, load management, and reliable authentication and billing services. Yet, designing an authentication scheme for dynamic EV charging presents significant challenges given the mobility of the EVs and the short contact time between the EVs and the charging segments. Accordingly, this work proposes a fast, secure and lightweight authentication scheme that allows only authentic EVs with valid credentials to charge their batteries while ensuring secure and fair payments. The presented scheme starts with a key pre-distribution phase between the charging service company (CSC) and the charging pad owner (PO), followed by a hash chain and digital signature-based registration and authentication phase between the EV and the CSC, before the EV reaches the beginning of the charging lane. These preliminary authentication phases allow the authentication between the EVs and the charging segments to be performed using simple hash key verification operations prior to charging activation, which reduces the computational cost of the EVs and the CS. Symmetric and asymmetric key cryptography are utilized to secure the communication between the different network entities. Analysis of the computational and transmission time requirements of the proposed authentication scheme shows that, for an EV traveling at 60 km/h to start charging at the beginning of the charging lane, the authentication process must be initiated at least 1.35 m ahead of the starting point of the lane as it requires ≃81 ms to be completed.

Queue Based Dynamic Charging Resource Allocation and Coordination for Heterogeneous Traffic in an Electrical Vehicle Charging Station

ABSTRACT Electric vehicle (EV) fast-charging stations (CSs) with innovative operation management strategies can help to meet the growing EV charging needs. Despite the short charging time associated with the fast charging of EVs, massive deployment of plugged-in EVs for fast charging triggers network surges in the distributed network. Nevertheless, these challenges can be effectively addressed with appropriate EV admission control, charging resource allocation, and coordinated charging strategies. This work proposes an innovative EV-CS operation mechanism that maximizes the CS profit by allowing fast charging EVs to access the CS opportunistically without stressing the distributed network. Furthermore, a queue is employed in the dynamic resource allocation process to favor more fast charging requests through buffering non-critical slow charging EVs, as fast charging users would otherwise be blocked or forcibly terminated. Performance of the proposed priority-based charging coordination is analyzed in terms of the optimum utilization of demand limit, charging completion rate, and charging station utilization. Therefore, it keeps the average charging station utilization above 90% at higher arrival rates of EVs while the distribution transformer is being loaded only up to 50% of its rated capacity. Moreover, the blocking and forced termination probabilities of fast charging users are used to evaluate the service quality of EV charging. The presented dynamic resource allocation and charging coordination strategies for heterogeneous EV traffic maximize the CS profit while assuring quality service to EV users without stressing the distributed network.

Elaboration of Porous Salts.

A large library of novel porous salts based on charged coordination cages was synthesized via straightforward salt metathesis reactions. For these, solutions of salts of oppositely charged coordination cages are mixed to precipitate MOF-like permanently porous products where metal identity, pore size, ligand functional groups, and surface area are highly tunable. For most of these materials, the constituent cages combine in the ratios expected based on their charge. Additional studies focused on the rate of salt metathesis or reaction stoichiometry as variables to tune particle size or product composition, respectively. It is expected that the design principles outlined here will be widely applicable for the synthesis of new porous salts based on a variety of charged porous molecular precursors.

A Secure Lightweight Hardware-Assisted Charging Coordination Authentication Framework for Trusted Smart Grid Energy Storage Units

A Secure Lightweight Hardware-Assisted Charging Coordination Authentication Framework for Trusted Smart Grid Energy Storage Units

Green Power Electricity Generation Devices Using Blockchain-Based Accent

Power storage systems offer numerous attractive characteristics of contemporary smart grids such as improved system stability, efficient demand response, and lower bills. Uncoordinated loading of ESUs, though is exhausting and can lead to an end of the power system. This paper uses blockchain and intelligent agreements to create a decentralised loading system with no need for a centralised load coordinator. The first ESU tokens can be used for authenticating itself anonymously in the blockchain. The ESU will give a request to charge the clever agreement address for the blockchain. This includes the state-of-charge (SoC), time to comprehensive chariots (TCC) and the quantity of charge required. This smart contract will then run the charge coordination process self-running, to postpone stresses for lower priority ESUs on potential time slots. ESUs with the top priorities are paid on the current slot. Each ESU should ensure the accurate measurement of charging schedules. Finally, our study indicates that performance costs can be appropriate in terms of gas usage while allowing de-central charge coordination, while increasing transparency, trustworthiness, and privacy conservation. We applied the projected gadget for the Ethereum test bed blockchain.

Coordination of Charging Plug-in Electric Vehicles (PEV) in Electric Distribution Networks to Minimize Power Losses and Voltage Deviations

Plug-in Electric Vehicle (PEV) is a vehicle with a drive in the form of an electric motor and gets its energy source from a rechargeable battery. PEV (grid-to-vehicle, or G2V) charging activity can pose a risk to the distribution system when PEV is injected into the system. Charging PEV in the distribution system will cause the demand for electrical power to increase. Without a proper and optimal charging coordination system for the many PEVs that exist in the distribution network system, the following technical problems will arise in the network such as: occurrence of unusual and unwanted peak loads in power consumption, voltage sag, transformers or conductors overload, as well as the occurrence of high power system losses in the distribution system. This study discusses the optimization of PEV charging coordination scheduling in a distribution system by considering power losses and voltage deviations. To optimize the coordination of PEV charging, this study used a metaheuristic method called the Binary Particle Swarm Optimization (BPSO) which was then compared with the Binary Gray Wolves Optimization (BGWO) method. This scheme is simulated on the 20kV Pujon Feeder distribution system in Malang, Indonesia. The initial simulation results, at the time when the most loads were presented, showed 80 percent of PEV penetration, increase in power losses of 54.51 percent and voltage deviation of 9.82 percent. By using the BPSO method, the results showed power loss increase of 27.2 percent and voltage deviation of 7.75 percent. Meanwhile, by using the BGWO method the increase in power losses was 31.09 percent and the voltage deviation was 7.98 percent.

Review of Communication Technologies for Electric Vehicle Charging Management and Coordination

Recently, electric vehicles (EVs) have been introduced as an alternative method of transportation to help mitigate environmental issues, such as carbon emissions and fuel consumption, caused by conventional transportation systems. The implementation of effective EV charging systems is essential to motivate mass adoption of EVs. Accordingly, fast and reliable communications between the charging systems and the EVs are vital for efficient management of the charging process. Different radio access technologies (RATs) are discussed in the literature to enable communication between the highly mobile EVs and the charging subsystems, to collect and exchange information such as state of charge (SoC), users’ locations, and charging decisions between the different network entities. This information can be used to coordinate charging plans and select the optimal routes for moving vehicles. This paper presents a survey of existing literature on vehicular communications for EV charging coordination and management. The communication requirements and feasible communication technologies for vehicular communication are first discussed in details. A review of the physical layer security strategies is then presented and the role of the different RATs in EV charging coordination and management is described and studied.

Local Stackelberg Equilibrium Seeking in Generalized Aggregative Games

We propose a two-layer, semi-decentralized algorithm to compute a local solution to the Stackelberg equilibrium problem in aggregative games with coupling constraints. Specifically, we focus on a single-leader, multiple-follower problem, and after equivalently recasting the Stackelberg game as a mathematical program with complementarity constraints (MPCC), we iteratively convexify a regularized version of the MPCC as inner problem, whose solution generates a sequence of feasible descent directions for the original MPCC. Thus, by pursuing a descent direction at every outer iteration, we establish convergence to a local Stackelberg equilibrium. Finally, the proposed algorithm is tested on a numerical case study involving a hierarchical instance of the charging coordination of Plug-in Electric Vehicles (PEVs).

Centralised coordination of EVs charging and PV active power curtailment over multiple aggregators in low voltage networks

Widespread application of residential photovoltaic (PV) systems and electric vehicles (EVs) has led the distribution system operators (DSOs) to face new technical challenges such as overloading and significant voltage variations, especially on low voltage (LV) grids. This adverse effect may be mitigated by employing the aggregators as intermediary actors to coordinate the operation at the distribution level. Therefore, this paper proposes a centralised coordination strategy to mitigate both PV and EV impacts, such as voltage rising/dropping at noon or evening, respectively, by defining the optimal export limit of PV power and EVs charging among multiple aggregators at the DSO level. The latter is in charge to dictate the optimal aggregated signals to every aggregator by employing a mixed-integer quadratic programming (MIQP) approach. The aggregated PV power is evenly managed for each aggregator by weighting. Two convex optimisation models are defined to satisfy both power and voltage constraints of the LV network. Each proposed optimisation approach can be utilised when there is or no detailed information about the LV network topology. The concepts discussed in this paper are tested on a real low voltage network considering a critical penetration level of EVs and PVs.

Online charging coordination of electric vehicles to optimize cost and smoothness

A large number of electric vehicles (EVs) operating in cities result in huge charging demands. For a charging station, it is important to balance between the charging cost and the future maintenance cost. In this paper, we present two bi-objective optimization models for optimizing charging cost and maintenance cost. From the perspective of maintenance cost, we consider to smooth the charging rate of the whole charging station and the charging rate of each charging port. Based on the two optimization models, we propose two heuristic online charging coordination algorithms called OCC-CSS (Cost and Station Smooth) and OCC-CPS (Cost and Port Smooth) to schedule the charging rate of EVs respectively. To evaluate their effectiveness, a series of simulations are conducted based on a real-world charging dataset of EVs. The results show that the two algorithms can achieve a nice trade-off between cost and smoothness, while keeping the ratio of service rejection near zero. Meanwhile, OCC-CPS achieves a better trade-off between cost and smoothness than OCC-CSS.

From Antiaromatic Norcorrolatonickel(II) to Aromatic and Nonaromatic Zwitterions: Innocent Ligands with Unbalanced Charge of the Core.

A three-component reaction of antiaromatic meso-mesityl-3-nitronorcorrolatonickel(II) 1-NO2 with dialkyl acetylenedicarboxylate and PBu3 yields aromatic zwitterionic corrole nickel(II) complexes 3-R with one of the meso-substituents comprising a positively charged tributyl phosphonium group and negatively charged coordination core. Reaction of 1-NO2 with PBu3 alone resulted in a nonaromatic chiral adduct 5 of a zwitterionic phlorine character with a −PBu3+ group at a pyrrole β-position.

Non-innocent Intercalation of Diamines into Tetragonal FeS Superconductor

We report two solvothermal pathways toward intercalated iron sulfide, [Fe8S10]Fe(en)3·en0.5 (en = ethylenediamine), featuring [Fe8S10]2– layers stacked by [Fe(en)3]2+ cations and free ethylenediamine molecules. [Fe8S10]Fe(en)3·en0.5 is synthesized in a simple single-step method from Fe and S in ethylenediamine with addition of NH4Cl mineralizer as well as from solvothermal treatment of mackinawite, tetragonal FeS. In situ synchrotron powder X-ray diffraction experiments reveal a clear transformation of tetragonal FeS into [Fe8S10]Fe(en)3·en0.5 upon reaction with ethylenediamine. In-house control synthetic experiments confirmed the chemical process, whereby ethylenediamine leaches iron solely from the tetragonal Fe–S layers to form [Fe(en)3]2+ complexes and thereby oxidize the intralayer iron to Fe2.25+. Our report emphasizes that, in layered iron chalcogenides, diamines can intercalate as charged coordination complexes in tandem with neutral diamine molecules.