V2G Mode Research Articles

Stochastic optimal scheduling of electric vehicles charge/discharge modes of operation with the aim of microgrid flexibility and efficiency enhancement

This paper proposes a three-level planning strategy for managing and optimizing electric vehicles (EVs) grid to vehicle/vehicle to grid (G2V/V2G) modes of operation with the aim of flexibility and efficiency enhancement in smart microgrids (SMs). In this three-level framework, G2V/V2G prices are determined via a non-cooperative game theory established between different entities including distribution company (DISCO), parking lots (PLs) and EV owners. Moreover, time-of-use (TOU) based demand response program (DRP) is utilized to increase the efficiency of the MG. In this approach, G2V/V2G modes of EVs in the electricity market is considered as a kind of commodity and EV’s V2G mode is utilized to improve the flexibility and efficiency of the MG. The transactions are done under the supervision of distribution system operator (DSO) on clearing prices. In addition to technical and economic issues, range anxiety (RA) is considered as an effective factor of participating EV owners in DR programs. The effectiveness of the proposed strategy has been evaluated via numerous simulation studies. The results show that the flexibility and efficiency of the MG increase by 0.29% and 67.37% using the proposed three-level framework compared to DRP case study, respectively.

Adaptive control-based Isolated bi-directional converter for G2V& V2G charging with integration of the renewable energy source

In this research paper, Adaptive control-based Isolated bi-directional converter for modernized electric vehicle system is introduced with control on charge and discharge of the electric vehicle (EV) battery as per the reference value. The EV battery is operated in two modes, such as charge (Grid-to-Vehicle) mode and discharge (vehicle-to-grid) mode. In charging mode, constant current and constant voltage (CCCV) control is adopted with control on charging voltage and current. Whereas in discharging mode, constant current (CC) control is adopted for control on discharge current from battery into the grid. The grid is also interconnected to PV system for renewable energy power sharing. In both the control techniques, ANFIS is integrated for better performance of the battery during charge and discharge conditions. The ANFIS takes input from error generated by comparison of reference and measured value and produces the required duty ratio value. The training of the fuzzy structure is done using data generated from the PI controller input and output. The training uses hybrid algorithm for adapting the data points considered from the PI controller. The EV battery is charged using the conventional AC grid and the renewable energy source in G2V mode, and the EV battery and renewable energy sources are used to supply power to the AC load in the V2G mode, which reducing the load demand on the AC grid. The DC-Link voltage and power to the AC load are kept constant in both modes of operation by using a synchronous reference frame controlled VSC and an ANFIS controlled dual active full bridge converter. The incremental conductance MPPT algorithm is used to control the Photo Voltaic Array (PVA). The proposed work is implemented using MATLAB/Simulink and HIL performance of the proposal system is examined in the RT-LAB OP-5700 real time simulator environment.

An improved compensation method for voltage sags and swells of the electric vehicles charging station based on a UPQC-SMES system

The immaturity of electric vehicles (EVs) in voltage regulation and the inconsistency of multiple vehicle-to-grid (V2G) functions are the issues that need to be addressed in V2G technology applications. To simultaneously deal with these issues, this paper proposes an electric vehicles charging station (EVCS) based on a unified-power-quality-conditioner-superconducting-magnetic-energy-storage (UPQC-SMES) system. The EVCS based on UPQC-SMES can regulate the regular power disturbances like the load current harmonics and grid voltage distortions. For voltage sags and swells, an improved compensation method based on V2G is proposed to enhance the protection of the faulty grid. It can be classified into 1) Mode 1, to regulate the power profile of the faulty grid with the maximum capability of the EVCS; 2) Mode 2, to minimize the volt-ampere (VA) loading of the UPQC with a specific compensation power and voltage injection angle which are related to the load impedance angle and fault level. A complete power flow analysis of the system is carried out combined with phasor diagrams, especially under the operation of the proposed method. Simulation results show that the modifications of EVs in the V2G mode can effectively mitigate the overcurrent and overvoltage during sags and swells. The feasibility and desirable dynamic characteristics of the proposed method are demonstrated by simulation, and the adopted 1.193-H/0.462-MJ SMES suppresses power fluctuations and stabilizes the DC-side voltage effectively. It ensures stable operation of the UPQC and a superior charging environment for the EVCS.

Airport electrified ground support equipment for providing ancillary services to the grid

The ground handling operations are used in airports for handling activities and processing passengers with the help of specially designed vehicles known as ground support equipment. The ground support equipment (GSE) is being parked after serving a flight until the next flight. The GSE idle duration between flights is depending on the flight schedule and can be turned into a profit source. This paper is presenting a methodology for electrified ground support equipment (EGSE) for providing frequency regulation ancillary services to the grid through an aggregator. The passengers flight schedule is considered to increase the vehicles’ availability to participate in the frequency regulation ancillary services market. The optimization model is formulated to maximize the airport profitability by using aggregation of EGSE in frequency regulation market. The results show that the EGSE provides a significant profit by participating in frequency regulation ancillary service with the use of V2G mode.

A V2G Enabled Bidirectional Single/Three-Phase EV Charging Interface Using Modular Multilevel Buck PFC Rectifier

The battery charging power electronics interface of an electric vehicle (EV) must be capable of bidirectional power flow to enable both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operations. In the presence of a single/three-phase AC supply, the front-end of the EV charger employs a power factor correction (PFC) rectifier, which should have the bidirectional capability to facilitate V2G mode. A conventional active rectifier functions in boost mode while performing PFC and voltage regulation. In most of the currently available EVs, however, the battery nominal voltage is low and, hence, a downstream high step-down DC-DC converter and high voltage DC bus capacitor are required in the charging interface. To overcome these issues, this work proposes a bidirectional AC-to-DC buck rectifier topology that can operate in G2V and V2G modes, both in single- and three-phase versions. The proposed topology utilizes the switched capacitors principle to achieve self-balancing of voltages in the capacitors. In addition, it is highly modular in structure. This paper describes the proposed topology, its working and modulation and its applications. The hardware proto model is used to validate the proposed power converter and the control approach to achieve PFC and voltage regulation. In addition, a comparison with other topologies is presented to demonstrate its competence.

An Assessment Method for the Impact of Electric Vehicle Participation in V2G on the Voltage Quality of the Distribution Network

In order to further evaluate the impact of vehicle-to-grid (V2G) on the distribution network, this paper studies a method to assess the influence of electric vehicles participating in charge and discharge on the voltage quality of the distribution network. First, considering the state of charge of the EV, the participation of the owner and other factors, the charging and discharging model is built. Then, the probabilistic power flow calculation based on Latin hypercube sampling is used to obtain the probability distribution of the voltage amplitude of the charge and discharge load connected to the distribution network, and finally the evaluation index is established to quantify and calculate the voltage quality of the distribution network participating in the V2G process of electric vehicles. Simulation results show that the evaluation method has the advantage of fast calculation speed while ensuring known accuracy, introduces the probability distribution of expected value and variance quantification of voltage amplitude, more intuitively understands the degree of influence on voltage quality before and after V2G, and can effectively assess the impact of electric vehicles accessing the distribution network in V2G mode on the power quality of low-voltage residential areas and industrial and commercial areas, and this evaluation method can provide useful reference for the formulation of future V2G control strategies and the planning of future urban power grids.

RETRACTED: A robust vehicle to grid aggregation framework for electric vehicles charging cost minimization and for smart grid regulation

In this paper, we propose an optimal hierarchical bi-directional aggregation algorithm for the electric vehicles (EVs) integration in the smart grid (SG) using Vehicle to Grid (V2G) technology through a network of Charging Stations (CSs). The proposed model forecasts the power demand and performs Day-ahead (DA) load scheduling in the SG by optimizing EVs charging/discharging tasks. This method uses EVs and CSs as the voltage and frequency stabilizing tools in the SG. Before penetrating EVs in the V2G mode, this algorithm determines the on arrival EVs State of Charge (SOC) at CS, obtains projected park/departure time information from EV owners, evaluates their battery degradation cost prior to charging. After obtaining all necessary data, it either uses EV in the V2G mode to regulates the SG or charge it according to the owner request but, it ensure desired SOC on departure. The robustness of the proposed algorithm has been tested by using IEEE-32 Bus-Bars based power distribution in which EVs are integrated through five CSs. Two intense case studies have been carried out for the appropriate performance validation of the proposed algorithm. Simulations are performed using electricity pricing data from PJM and to test the EVs behaviour 3 types of EVs having different specifications are penetrated. Simulation results have proved that the proposed model is capable of integrating EVs in the voltage and frequency stabilization and it also simultaneously minimizes approximately $1500 in term of charging cost for EVs contributing in the V2G mode each day. Particularly, during peak hours this algorithm provides effective grid stabilization services.

Single-Phase, Bidirectional, 7.7 kW Totem Pole On-Board Charging/Discharging Infrastructure

In the present scenario of the fossil fuel crisis, a shift from conventional transportation to electric vehicles (EVs) is the goal, and it is necessary to make it economically feasible. Developing an efficient charger with mid-range power level may successfully resolve this problem. In this direction, an EV charging infrastructure has been proposed to achieve grid-to-vehicle (G2V) charging, with vehicle-to-grid (V2G) capability. In G2V mode, the proposed infrastructure consists of an on-board, single-phase, 7.7 kW totem pole converter in continuous conduction mode to achieve high-power factor correction (PFC). Additionally, instead of conventional Si power MOSFET, an SiC-based converter is introduced to lower the switching losses at high switching frequency with smaller filters. Using an SiC-based converter leads to increased efficiency (more than 98%) and reduced total harmonic distortion (less than 5%), making the system economical. Simultaneously, to make the system more economical, the proposed converter works as an inverter to feedback the power to the grid in V2G mode. Furthermore, to analyse the feasibility, the proposed infrastructure has been simulated and its performance is validated using the simpower tool in MATLAB/Simulink environment.

Analysis of modified plug-in electric vehicle charger controller with grid support functionalities.

Power quality issues, which are mainly due to power electronic devices that are invariably used not only in domestic sector but also industries, still persist despite various mitigation strategies. The slow but steady invasion of Electric vehicles or Plug-in Electric Vehicles (PEVs) in recent years, in the automobile sector, adds woes to the power quality issues further. Majority of the charging systems presently available for charging PEVs are unidirectional and so supports Grid to Vehicle (G2V) mode only as the bidirectional integration of those vehicles into the grid is still a big challenge. However, Vehicle to Grid (V2G) support mode also deserves an equal importance as the PEV charger with V2G mode of operation is capable of supporting grid functionalities also, on need basis, which largely depends on the power circuit topology and controller topology it uses. Hence, in this work an improved controller topology has been designed and developed to alleviate the burdens on the grid. Support for active power demand, voltage swell and sag mitigation, in addition to catering its prime objective of charging the batteries are focused. A Second Order Generalized Integrator Phase Locked Loop (SOGI-PLL) based controller has been developed and implemented in the proposed work to improve the transient response, apart from controlling the steady-state oscillations of the grid to which it is connected to. A single phase non-isolated bidirectional PEV charger with proposed control topology has been simulated in MATLAB-Simulink for vehicle support and grid support mode of operations. The simulation proves the satisfactory operation of the proposed charger in the four quarters of active power and reactive power (PQ) plane, thus complies the design objectives of bidirectional power flow. The results obtained from the simulation show improved performance in terms of DC link voltage overshoot, steady-state oscillations, overall efficiency, voltage and current Total Harmonic Distortions (THD)

Research on Reactive Power Compensation Control of V2G Vehicle-Mounted Converter Suitable for Sharing Scenarios

The paper proposes an electric drive reconfigurable on-board converter for V2G energy management in a shared scenario. The proposed convert is obtained by adding an auxiliary circuit to the existing PEV driving hardware. In V2G mode, the converter uses drive motor as a power inductor to reduce the volume and increase power density. This paper proposes a method to adjustment active power and reactive power separately, which have able to be used for reactive power compensation on the load side. The feasibility of the system is verified by experiments.

Economic and climate benefits of vehicle-to-grid for low-carbon transitions of power systems: A case study of China's 2030 renewable energy target

More and more attention has been given to the role of electric vehicles in reducing the economic cost and carbon emissions of the power system through the vehicle-to-grid (V2G) mode, as well as helping to integrate renewable energy power. The promotion of V2G mode needs to consider the effectiveness of policy costs, so it is urgent to estimate the potential benefits of V2G. In this paper, a multi-regional power dispatch and expansion model is constructed from the perspective of power system by taking China's plan to reach 1.2 billion kW of installed wind and photovoltaic power generation capacity in 2030 as an example, combining with the development planning of electric vehicles and power systems. The results show that by 2030, the implementation of unidirectional V2G and bidirectional V2G in China can reduce the total cost of power system by 2.02% and 2.08%, reduce the annual carbon emissions of the power system by 2.27% and 2.95%, and increase the total proportion of wind and photovoltaic power generation by 1.33% and 1.28% in the power mix. An increasing proportion of electric vehicles participate in V2G increases the proportion of new-installed wind generation and decreases that of photovoltaic power. Due to the high cost of battery degradation and the current power mix dominated by coal-fired generation, additional benefits of implementing bidirectional V2G over unidirectional V2G are limited.

Random Modeling of Optimal Economic, Security and Environmental Operation of Micro-grid by Managing Responsive Loads and Charging and Discharging Electric Vehicles

The micro-grid operator must provide the energy required by its customers at the lowest cost and consider issues such as greenhouse gas emissions and security. The operator is faced with a multi-objective optimization problem in which customer demand must be provided at the lowest cost and safely. This research provides a new energy management system for islanded micro-grids. The small size of the islanded micro-grids, the high level of intermittentoperationand the low inertia of distributed generation ofinverter energy production resources make the frequency and voltage security two vital factors in the energy management system, which must be managed alongside economic-environmental policies. In this study, two practical tools are provided to help with the optimal operation and increase the profitability of the micro-grid operator. The first tool is the optimal and managed use of the V2G mode of electric vehicles. In the proposed approach, not only the penetration of electric vehicles in the network is managed but also this equipment is used to solve some of the network's challenges. The second tool is responsive loads and demand response programs in order to achieve the goals of the micro-grid operator. Covering the uncertainty of renewable energy sourcesby responsive loads, and how to model a demand response program in a micro-grid, arefollowed in this study.The strategy pursued several goals, including reducing energy and load costs, reducing the cost of charging EVs, and improving network parameters and security, such as voltage and frequency.The results confirm the effectiveness of the proposed approach

Dynamic Modelling of a Solar Energy System with Vehicle to Home and Vehicle to Grid Option for Newfoundland Conditions

The dynamic modelling of a solar energy system with vehicle to home (V2H) and vehicle to grid (V2G) options for Newfoundland conditions is discussed in this paper. A site (13 Polina Road) was chosen in St. John's, Newfoundland, Canada. An optimized system was built for the chosen site using BEopt, Homer, and MATLAB software’s to meet the house's energy demand. Furthermore, smart current sensors installed in the house are used to incorporate the V2H and V2G concepts. The Nissan Leaf's battery is used to supply household loads in V2H operation mode when the power supplied by the PV panel and the storage energy in the inhouse battery is less than the load's energy demand. In V2G mode, the vehicle is only linked to grid. Along with the simulation results, detailed system dynamic modelling is also presented. There are nine different system control modes that are proposed and simulated.

Unified Power Converter Based on a Dual-Stator Permanent Magnet Synchronous Machine for Motor Drive and Battery Charging of Electric Vehicles

An electric vehicle (EV) usually has two main power converters, namely one for the motor drive system and another for the battery-charging system. Considering the similarities between both converters, a new unified power converter for motor drive and battery charging of EVs is propounded in this paper. By using a single unified power converter, the cost, volume, and weight of the power electronics are reduced, thus also making possible a reduction in the final price of the EV. Moreover, the proposed unified power converter has the capability of bidirectional power flow. During operation in traction mode, the unified power converter controls motor driving and regenerative braking. Additionally, during operation in battery-charging mode, with the EV plugged into the electrical power grid, the unified power converter controls the power flow for slow or fast battery charging (grid-to-vehicle (G2V) mode), or for discharging of the batteries (vehicle-to-grid (V2G) mode). Specifically, this paper presents computer simulations and experimental validations for operation in both motor-driving and slow battery-charging mode (in G2V and V2G modes). It is demonstrated that the field-oriented control used in the traction system presents good performance for different values of mechanical load and that the battery-charging system operates with high levels of power quality, both in G2V and in V2G mode.

Optimal Configuration Method for EV Charging Station in Distribution Network Considering User Adjustment under V2G mode

The existing charging piles planning method of distribution network does not consider the influence of user participation in regulation. Hence, an optimal planning method of electric vehicle charging piles in V2G mode is proposed, considering users’ influence of regulation. An EV charging pile planning model is established to minimize the investment and operation cost of distribution network and charging station, and the genetic algorithm with elitist retention strategy is used to solve the model. The examples show the effectiveness of the proposed method.

Multi-Objective Coordinated Optimal Allocation of DG and EVCSs Based on the V2G Mode

With the vigorous promotion of new energy sources and the development of vehicle-to-grid (V2G) technology, the influence of the V2G mode should be considered in the joint optimal allocation of Distributed Generation (DG) and electric vehicle charging stations (EVCSs). The timing characteristics of the intermittent output of DG, conventional demand for load, and charging load of the electric vehicle (EV) are considered, as is its participation in grid interaction to examine the construction of typical scenarios and the EV cluster dispatching strategy. From the perspective of comprehensively planning the coordination of the distribution network, a DG-EVCSs bi-level joint planning model is established under the peak and valley price mechanism, with the sub-objectives of obtaining a comprehensive profit and high quality of voltage, curbing system load fluctuations, and satisfactorily charging the EV. An improved harmony particle swarm optimization algorithm is proposed to solve the bi-level model. The proposed method was tested on the IEEE-33 and the PG&E-69 (Pacific Gas and Electric Company) bus distribution systems, and the results show that the optimized configuration model that considers the V2G mode can improve the overall performance of the planning scheme, promote the use of clean energy, smoothen the load fluctuations of the system, and improve the quality of voltage and charging satisfaction of EV users.

Interconnected Operations of Electric Vehicle to Grid and Microgrid

This paper presents the development of a high-performance electric vehicle (EV) synchronous reluctance motor (SynRM) drive and its vehicle-to-grid (V2G) and vehicle-to-microgrid (V2M) bidirectional operations. The EV motor drive boostable DC-link voltage is established by a battery through a bilateral interface boost-buck DC-DC converter for good driving performance over a wide speed range. The motor efficiency is 92.3% near the rated load. In idle conditions, the embedded interface converter and inverter of the motor drive can be arranged to perform the G2V/V2G operations by adding external LC low-pass filters. The on-board battery can be charged from the mains in G2V mode with good line-drawn power quality. Alternatively, in V2G mode, the battery can send the preset power back to the utility grid with good current waveform quality. Besides, the same schematics can also conduct the M2V/V2M operations. A wind switched-reluctance generator (SRG) based microgrid is used as a test plant. The EV mobile energy storage application to microgrids is successfully offered through the arranged controls for effectively utilizing renewable sources. The measured results verify the normal operations with satisfactory performances for all power stages and operation cases.

Optimal bidding strategy for virtual power plants considering the feasible region of vehicle‐to‐grid

With the rapid development of vehicle-to-grid (V2G) technology, the use of the internet of things and advanced information technology to achieve the optimal dispatch of large-scale plug-in electric vehicles (PEVs) has become an important focus of scientific research and engineering practice worldwide. In order to achieve a balance between mass distributed energy resources and the secure and economic operation of the power grid, the authors propose an optimal market bidding strategy for a virtual power plant considering the feasible region of V2G. A detailed battery model considering the V2G mode of PEVs is established. A two-stage stochastic optimisation model for the virtual power plant considering massive volumes of PEVs is built, taking into account the day-ahead market revenue and the costs brought about by real-time market deviations. Three bidding strategies—PEVs charging immediately after arrival, without V2G, and considering V2G—are compared using case studies to demonstrate the efficiency and effectiveness of the proposed strategy. Through the complete interaction between PEVs and the virtual power plant, this V2G-based strategy can coordinate distributed energy resources, promote the accommodation of renewable energy, and significantly improve the economy of the virtual power plant operation.

Joint Expansion Planning Studies of EV Parking Lots Placement and Distribution Network

Long-term distribution network planning (DNP) is considered as one of the most challenging issues for distribution network operators (DNOs). By increasing EVs in cities, it has appeared some new players such as electric vehicles (EVs) owners and electric vehicle parking lots (EVPLs) owners for DNP. In this article, we conduct a new study on the coupled dynamic expansion problem of EVPLs placement and distribution networks. To reach this goal, at first, EVs driving and charging/discharging behavior as some influential factors is modeled using an efficient probabilistic algorithm. An analytical model is then introduced to estimate the number of EVs in EVPLs at different times. To find out the optimal place for installing EVPLs and distribution network reinforcement, a multiobjective (MO) optimization model is formulated considering the main requirements of EVs users, EVPLs owners, and distribution system operators. A linear model is also derived for the energy monument of EVs in EVPLs and residential charging stations to be used in the mentioned MO expansion problem. Numerical results with various cases are presented to illustrate the main advantages of the proposed coupled expansion model. The simulation results indicate increasing the percentage of participated EVs in V2G leads to reduce the DNO costs and increase the EVPLs’ revenues. Moreover, the year of feeder reinforcement will be deferred by considering V2G mode and battery degradation.

Modeling and Control of a Multifunctional Three-Phase Converter for Bidirectional Power Flow in Plug-In Electric Vehicles

A nonlinear sliding-mode controller for a three-phase converter, utilized in plug-in electric vehicles (PEVs), is proposed in this paper. The proposed controller enables the utilized converter to perform multiple functions during different operating modes of the vehicle, i.e., grid-to-vehicle (G2V) and vehicle-to-grid (V2G) modes. The bidirectional three-phase converter and the proposed controller operate as a power factor correction circuit, bridgeless boost converter, and rectifier during G2V mode (i.e., plug-in charging), and it operates as a conventional single-stage inverter during V2G mode. The stability analysis of the proposed controller is performed by defining a proper Lyapunov function. The functionality of the proposed nonlinear controller is first evaluated through simulation studies. The feasibility and effectiveness of the proposed control strategy is then validated using an industrial control card through a hardware-in-the-loop (HIL) experimental testbed.