Electrifying transportation is a promising approach to alleviate the climate change issue. The adoption of electric vehicle into market has introduced significant impacts on various fields, especially the power grid. Various policies have been implemented to foster the electric vehicle deployment and the increasing trend of electric vehicle adoption in the recent years has been satisfying. The continual development of electric vehicle power train, battery and charger technologies have further improved the electric vehicle technologies for wider uptake. Despite the environmental and economical benefits, electric vehicles charging introduce negative impacts on the existing network operation. Appropriate charging management strategies can be implemented to cater for this issue. Furthermore, electric vehicle integration in the smart grid can bring many potential opportunities, especially from the perspective of vehicle-to-grid technology and as the solution for the renewable energy intermittency issue. This paper reviews the latest development in electric vehicle technologies, impacts of electric vehicle roll out and opportunities brought by electric vehicle deployment.

A review on the state-of-the-art technologies of electric vehicle, its impacts and prospects

Energy crisis and environmental issues have encouraged the adoption of electric vehicle as an alternative transportation option to the conventional internal combustion engine vehicle. Recently, the development of smart grid concept in power grid has advanced the role of electric vehicles in the form of vehicle to grid technology. Vehicle to grid technology allows bidirectional energy exchange between electric vehicles and the power grid, which offers numerous services to the power grid, such as power grid regulation, spinning reserve, peak load shaving, load leveling and reactive power compensation. As the implementation of vehicle to grid technology is a complicated unit commitment problem with different conflicting objectives and constraints, optimization techniques are usually utilized. This paper reviews the framework, benefits and challenges of vehicle to grid technology. This paper also summarizes the main optimization techniques to achieve different vehicle to grid objectives while satisfying multiple constraints.

Integration of electric vehicles in smart grid: A review on vehicle to grid technologies and optimization techniques

The integration of solar photovoltaic (PV) into the electric vehicle (EV) charging system has been on the rise due to several factors, namely continuous reduction in the price of PV modules, rapid growth in EV and concerns over the effects of greenhouse gases. Despite the numerous review articles published on EV charging using the utility (grid) electrical supply, so far, none has given sufficient emphasis on the PV charger. With the growing interest in this subject, this review paper summarizes and update all the related aspects on PV–EV charging, which include the power converter topologies, charging mechanisms and control for both PV–grid and PV-standalone/hybrid systems. In addition, the future outlook and the challenges that face this technology are highlighted. It is envisaged that the information gathered in this paper will be a valuable one-stop source of information for researchers working in this topic.

Electric vehicles charging using photovoltaic: Status and technological review

Electric vehicles (EVs) are becoming increasingly popular in many countries of the world. EVs are proving more energy efficient and environmental friendly than ICEVs. But the lack of charging stati...

A Comprehensive Review on Solar Powered Electric Vehicle Charging System

Vehicle-to-Grid (V2G) is a promising technology that allows the batteries of idle or parked electric vehicles (EVs) to operate as distributed resources, which can store or release energy at appropriate times, resulting in a bidirectional exchange of power between the ac grid and the dc EV batteries. This bidirectional exchange of power is realized using bidirectional power electronic converters that connect the grid with the EV battery. Most research on bidirectional converters for V2G applications focuses on using two dedicated power conversion stages – a bidirectional ac-dc conversion stage that helps in power factor correction, followed by a bidirectional dc-dc conversion stage that provides voltage matching. However, a single bidirectional ac-dc conversion stage can also facilitate V2G and grid-to vehicle (G2V) active power transfers. This paper reviews and compares the various bidirectional ac-dc and dc-dc converter topologies that facilitate V2G and G2V active power flows. Moreover, the paper discusses the various classes of charger/discharger systems reported for V2G applications, like on-board/off-board, integrated/non-integrated and conductive/inductive, and a comparative statement is made based on certain proposed criteria. Further, the current trends in the application of wide band-gap devices in high power-dense V2G capable converters and integration of renewable energy sources into EV charging/discharging infrastructures have also been discussed.

Review of power electronics in vehicle-to-grid systems

Widely applications of electric vehicle rely on popularization of charging station. With the increase in the number of charging station, the problem of grid pollution becomes worse and worse, and the charging hours must be decreased to raise the utilization rate of electric vehicle. This article proposes a novel unit power factor DC fast charger for electric vehicle charging stations. This DC fast charger, mainly used in fast-charging station, includes two modules: the input module is three-phase PWM rectifier and the output module is the phase-shift full-bridge converter. The two modules are controlled by only one DSP - TMS320F2812. The three-phase PWM rectifier overcomes traditional rectifier's shortcomings of low power factor and large harmonic, and is higher power than three-phase one-switch or two-switch power factor correction circuit. The phase-shift full-bridge converter is the isolated high-frequency DC-DC converter, and apt to be used in high power situation. Furthermore, the volume and weight of the proposed charger are decreased than conventional converter with grid-frequency transformer. A prototype of 10 kW Charger is constructed. The experimental results show that the novel DC fast charger has excellent electrical characteristics, and it can be applied to the electric vehicle charging stations.

A unit power factor DC fast charger for electric vehicle charging station

The number and variety of EVs batteries connected to grid continue to grow rapidly, which result in a heavy burden on grid. To solve this problem, it was proposed that electric vehicles could act as a new power source for grid, which is the concept of Vehicle to Grid (V2G). This paper proposed the photovoltaic charging station architecture by using a combination of the Z-source boost converter based on the battery charging strategy with the bi-directional PWM Inverter-Rectifier based on the V2G strategy in Smart Grids. In the photovoltaic charging mode, the PV arrays charge the battery by the Z-source boost converter. In V2G mode, the PWM Inverter-Rectifier transfers the active power and passive power according to the grid requirement, thus the EV batteries could be applied for the peak regulation and frequency regulation in grid. Also the EV battery could be used as storage system for renewable power system. The prototype of bi-directional PWM Inverter-Rectifier and Z-source dc-dc converter is developed. Finally, V2G and battery storage experiments are tested. Meanwhile the Z-source dc-dc converter voltage boost experiments are tested. Simulation and experiment results demonstrate that the prototype implements the power bi-directional transformation between power grid and electric vehicles, and the Z-source dc-dc converter achieves the voltage boost. Consequently V2G could significantly increase the smart gird system flexibility, and storage intermittent renewable energy from wind and solar.

The photovoltaic charging station for electric vehicle to grid application in Smart Grids

Since the high temperature proton exchange membrane fuel cells (HT-PEMFC) stack require a range of auxiliary equipments to maintain operating conditions, it is necessary to consider operation of related components in the design of HT-PEMFC systems. In this paper, a thermodynamic model of a vehicular HT-PEMFC system using phosphoric acid doped polybenzimidazole membrane is developed. The power distribution and exergy loss of each component are derived according to thermodynamic analysis, where the stack and heat exchanger are the two components with the greatest exergy loss. In addition, ecological functions and improvement potentials are proposed to evaluate the system performance better. On this basis, the effects of stack inlet temperature, pressure, and stoichiometric on system performance are analyzed. The results showed that the energy efficiency, exergy efficiency and net output power of the system achieved the maximum when the inlet gases temperature is 406.1 K. The system performance is better when the cathode inlet pressure is relatively low and the anode inlet pressure is relatively high. Moreover, the stoichiometry should be reduced to improve the system output performance on the basis of ensuring sufficient gases reaction in the stack.

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Thermodynamic Modeling and Performance Analysis of Vehicular High-Temperature Proton Exchange Membrane Fuel Cell System

Performance analysis and optimization of a novel vehicular power system based on HT-PEMFC integrated methanol steam reforming and ORC

Applications of electric vehicles need to build a large number of charging stations. In order to reduce the grid load, it is necessary to develop smart electric vehicle charging stations. The Electric vehicle charging stations communicate with the gird. The Electric vehicle charge at night to reduce the cost and the grid load, simultaneously fill the valley. When grid load increase, electric vehicles battery discharge to the grid to improve grid stability. As distributed storage units, electric vehicles are important components of smart grid. New technology of high power factor PWM rectifier-inverter is one of the key technologies for the smart electric vehicle charging system. In this paper, three-phase PWM rectifier used for smart charging and discharging system of electric vehicle is analyzed and designed. The paper includes the principle of PWM Rectifier-Inverter and direct current control strategy. Also, the SVPWM and system design of three-phase PWM rectifier are analyzed. A 10kW prototype is developed. Simulation and experiment results show that the three-phase PWM rectifier can improve power factor. From the experimental results, PWM rectifier implements the grid current sinusoidal and achieves the unit power factor.

Dongxu Li

Papers

A unit power factor DC fast charger for electric vehicle charging station

The photovoltaic charging station for electric vehicle to grid application in Smart Grids

Thermodynamic Modeling and Performance Analysis of Vehicular High-Temperature Proton Exchange Membrane Fuel Cell System

Performance analysis and optimization of a novel vehicular power system based on HT-PEMFC integrated methanol steam reforming and ORC

A novel high power factor PWM rectifier inverter for electric vehicle charging station