Wireless Charging Of Electric Vehicles Research Articles

An Overview of Dynamic Inductive Charging for Electric Vehicles

Inductive power transfer (IPT) technology offers a promising solution for electric vehicle (EV) charging. It permits an EV to charge its energy storage system without any physical connections using magnetic coupling between inductive coils. EV inductive charging is an exemplary option due to the related merits such as: automatic operation, safety in harsh climatic conditions, interoperability, and flexibility. There are three visions to realize wireless EV charging: (i) static, in which charging occurs while EV is in long-term parking; (ii) dynamic (in-motion), which happens when EV is moving at high speed; and (iii) quasi-dynamic, which can occur when EV is at transient stops or driving at low speed. This paper introduces an extensive review for IPT systems in dynamic EV charging. It offers the state-of-the-art of transmitter design, including magnetic structure and supply arrangement. It explores and summarizes various types of compensation networks, power converters, and control techniques. In addition, the paper introduces the state-of-the-art of research and development activities that have been conducted for dynamic EV inductive charging systems, including challenges associated with the technology and opportunities to tackle these challenges. This study offers an exclusive reference to researchers and engineers who are interested in learning about the technology and highlights open questions to be addressed.

Misalignment-Tolerant Dual-Transmitter Electric Vehicle Wireless Charging System With Reconfigurable Topologies

Wirelesscharging for electric vehicles (EVs) enjoys many benefits, such as convenience, safety, and automation. One of the major issues concerning EV wireless charging is misalignment tolerance along the door-to-door direction of the EV. This letter proposes a misalignment-tolerant dual-transmitter EV wireless charging system with a reconfigurable topology. At central positions, the system can be reconfigured to the S-S (series-series) topology where the two transmitting coils are connected in series to feed the load. At boundary positions, the two transmitting coils form the LCCC-S (inductor-capacitor-capacitor-capacitor-series) topology to enhance power transfer capability and tolerate weak couplings. In this way, not only the output power can be smoothed with door-to-door misalignment, but also wireless charging is guaranteed at weak couplings. Experimental results reveal that within the cover area of the transmitting coils, high-efficiency stable output can be achieved.

Stability Improvement and Overshoot Damping of SS-Compensated EV Wireless Charging Systems With User-End Buck Converters

The multiple fluctuations, such as grid DC input voltage, mutual inductance and the plug-in and plug-out of battery, may lead to instability and deterioration of dynamic performance of electric vehicle (EV) wireless power transfer (WPT) system. The overshoot issue can bring great current stress to EV WPT system, and may induce potential disastrous malfunction of the lithium-ion (Li-ion) battery. This study theoretically reveals the slow dynamic response and large overshoot of a traditional WPT system. For solving these issues, a reliable adaptive feedforward control scheme is proposed and applied in the user-side DC-DC converter, where the communication unit is eliminated. The feedforward loop is proved theoretically to suppress overshoot and system dynamic response. Besides, the feedforward control increases the selective range of control parameters, which can improve the system dynamics. Experiment results verifies that the proposed adaptive feedforward gain allows faster dynamics, and the aforementioned disturbances in EV WPT system can be solved while the system performance is not affected.

3-D Analytical Model of Bipolar Coils With Multiple Finite Magnetic Shields for Wireless Electric Vehicle Charging Systems

The bipolar pad is one of the most promising topologies in inductive power transfer (IPT) systems for electric vehicles. However, there is scant literature on the analytical model of the bipolar pad. In this article, a three-dimensional (3-D) analytical model of the IPT system including a bipolar transmitter and a square receiver is developed based on the superposition of two 2-D subdomain analytical models. Ferrite and the aluminum shields with finite dimension are taken into account on the transmitter and receiver sides. An analytical calculation of the mutual inductance is then carried out with respect to the main parameters of the IPT system, namely the dimension of the coils, the conductivity, and the permeability of the shield. Three study cases are demonstrated to highlight how the proposed method can accelerate speed up the pad design process. Calculation results of the proposed model are compared with both a finite-element analysis (FEA) model and experimental measurements, demonstrating that the proposed model is nine times faster than the FEA method. When comparing with the experimental results, computational error of the proposed model is less than 6% in most of the study cases.

Thermal Analysis of Coupled Resonant Coils for an Electric Vehicle Wireless Charging System

Electric vehicles use wireless energy transmission to obtain energy, which can effectively avoid the shortcomings of traditional methods. As the carrier of radio energy transmission and reception, the high temperature of the coil triggers the degradation of wireless transmission performance and the aging of the coil, which may cause fire and other safety problems in serious cases. This paper studied the temperature distribution of the magnetically coupled coil model for electric vehicles. Based on the study of the basic law of heat transfer, the coil model was established using ANSYS software, and the boundary conditions and relevant parameters were set. After many simulation experiments and comparisons, it was finally determined that the transmitting coil and the receiving coil were the same sizes, the inner diameter of the coil was 100 mm, the outer diameter of the coil was 181 mm, and the coupling distance between the transmitting coil and the receiving coil was set to 60 mm. Coil models were simulated and analyzed using different materials. The simulation results show that after 30 min of system operation, the material chosen from the temperature range may have been gold, silver, copper, or aluminum, but from the comprehensive consideration of cost and performance, the material of the coil in the model was finally set to copper. Copper was the best material; its temperature maximum was 74.952 °C and lower than the safety value of 80 °C. It is hoped that this study will provide a reference for wireless charging coil design.

Metal Object and Vehicle Position Detections Integrated With Near-Field Communication for Wireless EV Charging

To commercialize wirelesselectric vehicle charging (WEVC), three critical issues must be resolved: communication between the vehicle assembly (VA) and the ground assembly (GA), metal object detection (MOD) on the GA coil, and position detection (PD) of the VA. This paper proposes a comprehensive system that integrates MOD and PD with VA-GA near-field communication (NFC). A common high-frequency aided carrier is used not only for NFC, but also for MOD and PD. In addition, an array of dual-purpose detection coils is proposed as a sensor for MOD and PD. As a result, the three functions listed above share numerous components and circuits, greatly simplifying the system structure. Furthermore, because the high-frequency aided carrier can operate with or without a power carrier, the preceding three functions are independent of system power status. The proposed method has been validated using a 3.3 kW WEVC prototype operating at 85 kHz. The experimental results show that the proposed system is capable of performing both online and offline NFC, MOD, and PD with high sensitivity while having no impact on wireless charging efficiency.

Transportation systems management considering dynamic wireless charging electric vehicles: Review and prospects

This paper reviews and prospects the research in transportation systems management with the presence of dynamic wireless charging (DWC) electric vehicles (EVs). DWC is based on inductive coupling that allows EVs to get charged wirelessly by driving over the coils installed in the ground. Thus, DWC is also known as ‘charging-while-driving’ or ‘in-motion charging’, which is regarded as one of the most promising charging solutions for EVs. The road that is equipped with wireless chargers underneath its surface is called a wireless charging lane (WCL). The deployment of WCLs will lead to a profound change in the field of transportation systems management. We give a review of recent studies on related topics including WCL allocation and related decisions, energy consumption of EVs considering WCLs, and pricing of EVs for the use of DWC facilities. Based on the analysis of the existing studies, we identify the needs for more flexible WCL design and allocation models, as well as novel ways that incorporate the complexities in energy consumption by EVs and routing behaviour into traffic network analysis. In addition, we emphasise the research opportunities of dynamic traffic modelling and real-time control considering DWC and EVs with state-of-charge (SOC) constraints. A high-level dynamic system model and a general model-based control problem are formulated in this regard. Finally, we foresee a demand for finer traffic management in the WCL environment enabled by emerging technologies such as the internet of vehicles (IoV) and autonomous driving.

Blockchain-Based Privacy-Preserving Networking Strategy for Dynamic Wireless Charging of EVs

Dynamic wireless charging of electric vehicles (EVs) enables the exchange of power between a mobile EV and the electricity grid via a set of charging pads (CPs) deployed along the road. Accordingly, dynamic charging coordination can be introduced for a group of mobile EVs to specify where each EV can charge (i.e., from which CPs). This coordination mechanism maximizes the satisfied charging requests given the limited available energy supply. Upon specifying the optimal set of pads for a given EV, a fast authentication mechanism is required between the EV and the CPs to start the charging process. However, both the coordination and authentication mechanisms require exchanging private information, e.g., EV identities and locations. Hence, there is a need for a strategy that enables privacy-preservation in dynamic charging via supporting: (i) user anonymity and (ii) data unlinkability. In this paper, we propose a decentralized and scalable networking strategy based on a specially designed private blockchain that can support the privacy requirements of dynamic charging coordination, authentication, and billing. The proposed networking strategy relies on group signature and distributed random number generators to support the desirable features. Simulation results demonstrate the efficiency and low complexity of the proposed blockchain-based networking strategy.

A Self-Tuning LCC/SP System for Electric Vehicle Wireless Charging against Large Self- and Mutual Inductance Variations

An LCC/SP self-tuning wireless charging system is proposed herein for use in a wireless charging test bench. With different dislocations in addition to changes in the coil self-inductance and mutual inductance caused by different secondary magnetic shielding materials, the system can ensure that the high power factor of the primary side remains unchanged without changing the circuit topology. Based on this normalized detuning LCC/SP circuit model, a switch-controlled capacitor (SCC) self-tuning method based on PI control is proposed. The control scheme employs only two MOSFETs and capacitors, without WIFI communication or parameter identification. A 2 kW experimental device was set up in the laboratory, and experimental verification was carried out with large-scale dislocations and different secondary magnetic shielding materials. The experimental results confirm that the system can maintain a high power factor (>0.9) under a system mutual inductance variation of 47.7% and secondary coil self-inductance variation of 12%, and that it can be applied in electric vehicle wireless chargers or high-power wireless charger test benches.

Bidirectional wireless power/data transfer via magnetic field

Recently, inductive power transfer (IPT) system has been used for wireless charging of electric vehicles (EVs). However, most of them only treat the issue of single directional wireless power transfer (WPT). This research proposes a novel bi-directional IPT (BD-IPT) scheme EVs, which can simultaneously transmit power/data via magnetic field when the mutual inductance changes. For power transmission, resonant inverters with phase-shift pulse width modulation (PSPWM) are used to generate carrier waves and alternating current. As for data transmission, a dedicated communication method with the accompanied protocol is proposed. Binary phase shift keying (BPSK) is used to simulate the two-quadrature amplitude modulation (QAM), which generates digital signals for data transmission without the need of extra communication links. Hamming codes are combined with single-error correction and double-error detection (SECDED) to ensure communication quality.

A Simple and Reconfigurable Wireless Power Transfer System With Constant Voltage and Constant Current Charging

A typical charging profile for the Li-ion batteries in electric vehicles (EVs) includes a constant current (CC) charging stage and a constant voltage (CV) charging. This letter proposes a simple and reconfigurable topology for CC and CV outputs in an EV wireless charging system. The proposed system can be switched to series–series topology for CC output and inductor–capacitor–capacitor-series topology for CV output. Only one relay is introduced, unlike existing solutions where many passive components and relays are utilized for reconfiguration. Also, there is no need for frequency variation to achieve the shift of CC and CV. An experimental prototype is implemented to validate the proposal.

Dynamic Wireless Charging for Inductive Power Transfer Systems in Electric Vehicles

The charging plate creates magnetic fluxing. The charging plate and the adjacent coil can induce current without any contact. By the new trends, wireless charging got more social attention to the outside world as an alternative method for primitive wired charging. Even though wireless charging was implemented to various electronics industries, it is still proven that wired charging is faster than the wireless. But can make the gadget hot, which may not be good for the battery efficiency. The wireless charging does not degrade the battery. A vehicle that is powered by an electric motor rather than a typical petrol or diesel engine is referred to as an electric vehicle. The electric motor is powered by rechargeable batteries. In this article, the dynamic wireless charging of electric vehicles introduces a new methodology of charging even when the vehicle is in motion. The dynamic wireless charging is proposed to allow power transfer to the electric vehicles when they are in motion. Multiple inductive pads should be buried under the roadways. The inductive pads should be energized by a power supply. The track which is dedicated for the wireless charging should have enough distance so that the vehicles can charge up to a stable value until they leave the charging track. This proposed methodology reduces unnecessary time wastage for charging of vehicles. Hardware results obtained the primary pads mounted on road and power supply for primary roads. Besides, it will flow the efficient inductive power transfer and time saving opportunity.

Integrated Double-Sided LCC Compensation Topology for an Electric Vehicle Wireless Charging System

Wireless power transfer (WPT) is a necessary solution for removal of high power cables (direct electrical contact) that provides safer charging solution, waterproof and dust-proof capability, sterile environment application, etc. The double-sided LCC (DSLCC) compensation topology offers a high efficient Electric Vehicle (EV) wireless charging operations. Due to the number of elements utilized in DSLCC, it requires large space. In order to reduce the space and cost, class-E converters are utilized to design a low power wireless charging system. Class E converters have such benefits as less components, high reliability, and soft switching. Thus, to have a compact efficient Wireless Charging System (WCS) by reducing the space occupancy of DSLCC, an integrated DSLCC based wireless charging system for low power applications is proposed. This method was realized by utilizing the MATLAB simulation and achieved more than 90% of efficiency for 1 kW system with 85 kHz frequency.

Foreign object detection considering misalignment effect for wireless EV charging system

Foreign object detection (FOD) is crucial to preventing wireless electric vehicle charging (WEVC) systems from thermal risk caused by intruded metals in the charging area. In practice, the spatial misalignment between EV and ground-assembled power transmitter is evitable. Unfortunately, according to our quantitative analysis based on conventional voltage-difference-based method, a misalignment of merely tens of mm has been enough to severely deteriorate the FOD accuracy. To combat this misalignment effect, a FOD strategy based on passive sensing coils utilizing voltage vector decomposition (VVD) is proposed in this paper. The proposed strategy can be invariant to misalignment in an automatic manner, during the whole charging process, and regardless of the resonance state of charging circuit. To facilitate VVD implementation, a method called inductance-misalignment mapping (IMM) is devised to obtain the spatial misalignment of EV in real time, and it can be executed by reusing the sensing coils without introducing extra cost. The effectiveness of optimized sensing coils with the proposed FOD method is validated successfully using a commercialized 3-kW prototype working from light load to rated load.

Bi-level framework for microgrid capacity planning under dynamic wireless charging of electric vehicles

The battery energy storage system in the microgrid can regulate energy and maintain the stability and continuity of renewable energy generation. This paper presents a new microgrid structure with in-motion electric vehicles as a distributed energy storage system. This structure combines the technology of dynamic wireless charging, allowing in-motion electric vehicles to participate in the energy regulation of the microgrid. The proposed microgrid mainly consists of wind turbines, photovoltaic arrays, as well as dynamic wireless charging facility. Two different planning objectives, i.e., maximizing the microgrid utility and minimizing the total generalized social cost, are investigated respectively. Taking into account the response of EV users to the microgrid capacity plans, we propose a bi-level framework. Further, an algorithm based on the surrogate model is used to solve the bi-level programming, where the radial basis function interpolation model is utilized to approximate the objective function. Finally, in case studies, the influence of parameter variations on the results is explored. The feasibility and advantages of the proposed microgrid capacity planning are demonstrated. Further, through the studies of the uncertainties of wind speed, light intensity, base load, and movable load, it is illustrated that the objective value can maintain good stability under the optimal capacity plan.

전기자동차용 무선 전력 충전의 적정 선정을 위한 자기 공진 회로구조의 비교 분석

In this paper, four circuits of magnetic resonance circuit systems for improving the performance of wireless power charging for electric vehicles were compared and analyzed. Currently, wireless charging is widely used in real life and commercialized, and a wireless charging method is being studied to compensate for the problems of the wired charging method of electric vehicles. In order to wirelessly charge an electric vehicle, a magnetic resonance method is used, and to compare the efficiency of the most basic four magnetic resonance circuit system structures, parameters are obtained through the design formula of the magnetic resonance circuit system, and the efficiency of each magnetic resonance circuit system are compared and analyzed through PSIM.

Cost-Efficiency Optimization of Ground Assemblies for Dynamic Wireless Charging of Electric Vehicles

Dynamic wireless power transfer (DWPT) allows electric vehicles (EVs) to be charged while in motion. However, high cost and efficiency concerns limit the widespread adoption of DWPT. A ground assembly (GA) accounts for most of the system cost since it is implemented on a significant portion of the road. This article proposes a cost-efficiency optimization algorithm to determine the optimum design of a DWPT transmitter (Tx) pad. Elongated rectangular pads are considered a compromise between cost and efficiency. An optimization methodology is put forward to maximize Tx pad efficiency while minimizing GA cost over a selected road. The optimum design allows constant power transfer inside a selected rated power zone while considering EV lateral misalignment as a random variable. Main cost factors are accounted for, including the cost of the pad coil Litz wire and ferrite material and Tx power electronics and compensation network. Particle swarm optimization allowed the number of finite element analysis simulations to be reduced by intelligently selecting test designs. Statistical analysis is applied to understand the impact of different variables on the final design and the interdependence between variables. Additional analyses are conducted to evaluate the impact of different DWPT aspects, including the wire gauge, probability density of the misalignment variable, multilayer coil design, and capacitor cost modeling. The algorithm is used to design a 3.7-kVA Tx pad with respect to the SAE J2954 receiver test stand VA WPT1/Z1. The optimization Pareto fronts illustrate the family of optimum designs, while the chosen 3.7-kVA pad offers the statistical expected value of pad efficiency as 96%, GA per meter cost of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\$ $ </tex-math></inline-formula> 1004, and an optimum pad length of 1.75 m. The 3.7-kVA optimized pad is manufactured and tested for several operating conditions verifying the simulation results.

Wireless Charging of Electric Vehicles Using Dual Spiral Coil Magnetic Resonant Coupling

Abstract: As we get into a new decade in the 21st century, the progress of electric automobiles has been on a significant rise but still flawed with things like range anxiety, limited number of charging stations, high price range etc. But one of the most important flaw is the range anxiety especially in countries like India where we spend half the time stuck in traffic. So, to overcome that we have come up with a project whose technology is still in development and is being tested worldwide. One method to avoid this is by the introduction of Wireless charging into Electric vehicles which is the main focus of this paper.

Review of Static and Dynamic Wireless Electric Vehicle Charging System

Abstract: Electrified transportation will contribute to the reduction of greenhouse gas emissions and the stabilization of gasoline costs. To promote the adoption of electrified transportation, a diverse network of charging stations must be established in a userfriendly environment. Wireless electric vehicle charging systems (WEVCS) have the potential to be a viable alternative technology for charging electric cars (EVs) that do not need a plug. This article discusses the present state of wireless power transfer technologies for electric vehicles. Additionally, it contains wireless transformer constructions that have been studied using a range of ferrite forms. WEVCS are linked with health and safety concerns, which have been addressed in recent international standard development. Two main applications, static and dynamic WEVCS, are discussed, and current development is documented using features from research labs, universities, and industry. Additionally, future concepts-based WEVCS are evaluated and studied, including "vehicle-to-grid (V2G)" and "in-wheel" wireless charging systems (WCS), with qualitative comparisons to other current technologies Keywords: Combustion, Diesel Engine, Turmeric Oil, Vibration Analysis, Methyl Ester, and Blends

Electromagnetic Interference in a Buried Multiconductor Cable Due to a Dynamic Wireless Power Transfer System

The aim of this study is to predict the electromagnetic interference (EMI) effect produced by a dynamic wireless power transfer (DWPT) system on a buried multiconductor signal cable. The short-track DWPT system architecture is here considered with an operating frequency of 85 kHz and maximum power transferred to an EV equal to 10 kW. The EMI source is the DWPT transmitting coil which is activated when a vehicle passes over it. The electric and magnetic fields in the earth produced by the DWPT coil currents are calculated numerically using the finite elements method (FEM). These fields are then used to derive the voltage and current sources that appear in the field-excited multiconductor transmission line (MTL) model, used for the buried shielded cable. The MTL is analyzed considering the first ten harmonics of the current. The currents and voltages at the terminal ends are calculated considering the wireless charging of a single electric vehicle (EV) first, and then the simultaneous charging of 10 EVs which absorb a total power of 100 kW. The preliminary results reveal possible EMI problems in underground cables.