Potential of wireless power transfer for dynamic charging of electric vehicles

Abstract

Wireless Power Transfer (WPT) offers a viable means of charging Electric Vehicles (EV)'s whilst in a dynamic state (DWPT), mitigating issues concerning vehicle range, the size of on-board energy storage and the network distribution of static based charging systems. Such Charge While Driving (CWD) technology has the capability to accelerate EV market penetration through increasing user convenience, reducing EV costs and increasing driving range indefinitely, dependent upon sufficient charging infrastructure. This paper reviews current traction battery technologies, conductive and inductive charging processes, influential parameters specific to the dynamic charging state as well as highlighting notable work undertaken within the field of WPT charging systems. DWPT system requirements, specific to the driver, vehicle and infrastructure interaction environment are summarised and international standards highlighted in order to acknowledge the work that must be done within this area. It is important to recognise that the gap is not currently technological; instead, it is an implementation issue. Without the necessary standardisation, system architectures cannot be developed and implemented without fear of interoperability issues between countries or indeed systems. For successful deployment, the technologies impact should be maximised with the minimum quantity of infrastructure and technology use, deployment scenarios and locations are discussed that have the potential to bring this to fruition. IntroductionThe electrification of road transport provides a viable means of reducing fossil fuel consumption and environmental pollution, hence the recent advancements in Electric Vehicle (EV) design and performance [1]. However, the high costs and poor specific energy densities of batteries compared to fossil fuels results in a less than ideal scenario [2]. Due to their relatively shorter range, EV's require more frequent charging (than refuelling of Internal Combustion Engine (ICE) vehicles) to maintain a desirable range and with long charge times (compared with conventional refuelling times) or potential battery degradation that occurs during rapid charging; battery charging technology has restricted EV development. With no significant advancements in battery technology that would bring EV range in line with comparable ICE vehicles forecasted within the foreseeable future [3] this has resulted in substantial research into alternative charging methods. Whilst conventional plug in charging is the most common form, there are still conductive energy losses within the system resulting in an overall efficiency of around 86% [4] and potentially lower for rapid chargers. In addition, the high power transfer, human handling and the ability for the user to forget to plug in/out result in a pragmatic scenario.Wireless Power Transfer (WPT) technology is capable of mitigating the issues of plug in charging; the EV is parked over a coil that inductively transfers electrical energy to a receiver coil positioned on the vehicle. ...

Interdisciplinary Analysis of Social Acceptance Regarding Electric Vehicles with a Focus on Charging Infrastructure and Driving Range in Germany

“…at a maximum power of 150 kW [100]. It is advisable to only charge batteries to 80% of the maximum SoC during fast charging to protect the batteries and to extend their service life [101]. Table 6 are intended to provide an overview of standards regarding conductive charging.…”

Integrated system for power flow control between electric vehicle, utility grid and residence

“…When considering the residential application, it is expected that an EV will drain around 1.9 kW from a 230 V single‐phase grid for a slow charging between 11 and 36 h, as suggested in [12, 18]. Higher power levels are also found in practical applications.…”

Grid Integration and Impact Analysis of High-Power Dynamic Wireless Charging System in Distribution Network

“…Various studies have been conducted on DWCS in terms of coil design [5], [6], compensation network [7], [8], modeling and control method [9], [10], and communication techniques [11], [12]. A few existing papers explored grid integration of DWCSs in the view of distribution networks [13]- [17]. Since the charging window of dynamic wireless charging relates to the time period when the vehicle is above the transmitter coil, high-power transfer capability is required for DWCS to guarantee an amount of energy fed to the battery in a limited amount of time.…”

“…Since the charging window of dynamic wireless charging relates to the time period when the vehicle is above the transmitter coil, high-power transfer capability is required for DWCS to guarantee an amount of energy fed to the battery in a limited amount of time. Such a variable vehicle speed-related high-power pulsating load profile may cause considerable stress on the distribution networks [13], [14]. To mitigate the grid impact, a smart grid architecture and renewable energy integration were proposed in [15].…”