Inductive Charging Research Articles

Predictive Modeling for Detection of Source of Electromagnetic Disturbances in Inductive Wireless Charging of Electric Vehicles

The effects of Electromagnetic Interference (EMI) in Inductive Power Transfer (IPT) for electric vehicle charging circuits are elaborated with Common Mode (CM) emission. Electromagnetic Compatibility (EMC) has to be sustained in the circuits such that it is prone to the effects of interferences, noises and disturbances. These issues can be addressed at the initial product development stage, with accurate identification of the parameters that influence the CM emission in the circuit. The analysis of EMI focuses on three features, namely Source of EMI, Coupling path and Receptor. In the IPT model, the primary source of the EMI is the power converter used for high-frequency supply to the inductive coils. The power converter switches and the heat sink with its Printed Circuit Board (PCB) design are predominant in power electronic circuits. This paper facilitates the reduction of EMI without including complex filters. The system is tested for the violated standard SAEJ2954. In addition, the article corroborates precognitive modeling by implementing compensation networks used in IPT applications and their effectiveness in reducing the leakage current caused by the converters and the coils. The paper insights the air gap variation of the coil with the power transfer efficiency and its influence on electromagnetic interferences. The Fast Fourier Transform (FFT) analysis used in PSIM shows leakage current and harmonic reduction with the compensation network and Pulse Width Modulation (PWM) technique. The fabrication model for the front end power supply to the IPT is tested. The electrical noise emission is estimated using predictive modeling.

Virtual Inertia-Based Multipower Level Controller for Inductive Electric Vehicle Charging Systems

A method of modulating the power level of a grid-supplied inductive electric vehicle (EV) charger to provide frequency stabilization to the utility grid is presented. The proposed controller can allow inductive EV charging systems to effectively respond to grid frequency fluctuations by online regulating the charging level and adding high virtual inertia. A new IPT multipower level controller using simplified digital circuits is designed. The virtual inertia control/controller (VIC) is incorporated into the proposed multipower level controller which gets the grid frequency measurement and online adjust the IPT’s charging level. Using the proposed VIC IPT charger, the switching cycles, as a result, the power transfer from the grid to the EV can be regulated in response to the grid frequency change. The simulation results of the proposed VIC IPT power controller are presented to show its effectiveness in response to power grid fluctuations. The proposed virtual inertia based controller is experimentally implemented and verified on an IPT setup connected to an actual small-scale Labvolt testbed.

Design of High-Efficiency Inductive Charging System With Load-Independent Output Voltage and Current Tolerant of Varying Coupling Condition

Maintaining constant-current (CC) and constant-voltage (CV) outputs for meeting the charging profile of lithium-ion batteries while realizing zero-voltage-switching on the primary bridge over wide ranges of load and coupling variations are rather challenging due to the presence of leakage and magnetizing inductances of a loosely coupled transformer. Although the challenges can be greatly relaxed by properly designing a compensation network with load-independent output characteristics, the desirable characteristics rendered by fixed compensation networks will be lost and cannot be fully restored by existing control methods once the designed compensation is deviated from the nominal coupling condition. In this article, a dynamic series/series-parallel compensation network, which originally aims to deliver constant output voltage only, is further investigated as a feasible topology for CC-CV battery charger adaptive to different sizes of air gap/misalignment of the coils. As benefited from the extra controllability offered by the parallel compensation capacitance as compared to the series/series compensation counterpart, this article provides alternative design criterion for the effective parallel compensation capacitance for designing and maintaining desirable charging currents in the CC stage while maximizing the efficiency in the CV stage under varying coupling condition. An experimental prototype with the air gap ranging from 10 to 16 cm is built to verify the idea.

Towards real-time magnetic dosimetry simulations for inductive charging systems

PurposeInductive charging systems for electrically powered cars produce a magneto-quasistatic field and organism in the vicinity might be exposed to that field. Magneto-quasistatic fields induce electric fields in the human body that should not exceed limits given by the International Commission of Non-Ionizing Radiation protection (ICNIRP) to ensure that no harm is done to the human body. As these electric fields cannot be measured directly, they need to be derived from the measured magnetic flux densities. To get an almost real-time estimation of the harmfulness of the magnetic flux density to the human body, the electric field needs to be calculated within a minimal computing time. The purpose of this study is to identify fast linear equations solver for the discrete Poisson system of the Co-Simulation Scalar Potential Finite Difference scheme on different graphics processing unit systems.Design/methodology/approachThe determination of the exposure requires a fast linear equations solver for the discrete Poisson system of the Co-Simulation Scalar Potential Finite Difference (Co-Sim. SPFD) scheme. Here, the use of the AmgX library on NVIDIA GPUs is presented for this task.FindingsUsing the AmgX library enables solving the equation system resulting from an ICNIRP recommended human voxel model resolution of 2 mm in less than 0.5 s on a single NVIDIA Tesla V100 GPU.Originality/valueThis work is one essential advancement to determine the exposure of humans from wireless charging system in near real-time from in situ magnetic flux density measurements.

"The future lies in inductive charging"

"The future lies in inductive charging"

A Review of the Current State of Technology of Capacitive Wireless Power Transfer

Wireless power transfer allows the transfer of energy from a transmitter to a receiver without electrical connections. Compared to galvanic charging, it displays several advantages, including improved user experience, higher durability and better mobility. As a result, both consumer and industrial markets for wireless charging are growing rapidly. The main market share of wireless power is based on the principle of inductive power transfer, a technology based on coupled coils that transfer energy via varying magnetic fields. However, inductive charging has some disadvantages, such as high cost, heat dissipation, and bulky inductors. A promising alternative is capacitive wireless power transfer that utilizes a varying electric field as medium to transfer energy. Its wireless link consists of conductive plates. The purpose of this paper is to review the state of the art, link the theoretical concepts to practical cases and to indicate where further research is required to take next steps towards a marketable product. First, we describe the capacitive link via a coupling model. Next, we highlight the recent progress in plate topologies. Additionally, the most common compensation networks, necessary for achieving efficient power transfer, are reviewed. Finally, we discuss power electronic converter types to generate the electric field.

Automated Fiber Embedding for Soft Mechatronic Components

Many recent advances in smart composites for soft robotics have resulted from integration of long fibers to precisely control structural and functional properties. Compared to the time-consuming, laborious and error-prone process of manual long fiber placement typically used, Automated Fiber Embedding (AFE) has an enormous potential in soft robotics due to its repeatability, precision, and ease of integration with commonly used elastomers. In this work, three different approaches for automated layering and embedding of fibers inside silicone elastomers are presented. These techniques enable fabrication of soft composites comprising linear and free-form long fiber patterns without user intervention or manual post processing. To demonstrate the versatility of the techniques, several soft robotic applications ranging from actuators to inductive charging coils are presented.

Automated Vehicle Positioning System for Inductive Charging

Automated Vehicle Positioning System for Inductive Charging

An Intracortical Implantable Brain-Computer Interface for Telemetric Real-Time Recording and Manipulation of Neuronal Circuits for Closed-Loop Intervention.

Recording and manipulating neuronal ensemble activity is a key requirement in advanced neuromodulatory and behavior studies. Devices capable of both recording and manipulating neuronal activity brain-computer interfaces (BCIs) should ideally operate un-tethered and allow chronic longitudinal manipulations in the freely moving animal. In this study, we designed a new intracortical BCI feasible of telemetric recording and stimulating local gray and white matter of visual neural circuit after irradiation exposure. To increase the translational reliance, we put forward a Göttingen minipig model. The animal was stereotactically irradiated at the level of the visual cortex upon defining the target by a fused cerebral MRI and CT scan. A fully implantable neural telemetry system consisting of a 64 channel intracortical multielectrode array, a telemetry capsule, and an inductive rechargeable battery was then implanted into the visual cortex to record and manipulate local field potentials, and multi-unit activity. We achieved a 3-month stability of the functionality of the un-tethered BCI in terms of telemetric radio-communication, inductive battery charging, and device biocompatibility for 3 months. Finally, we could reliably record the local signature of sub- and suprathreshold neuronal activity in the visual cortex with high bandwidth without complications. The ability to wireless induction charging combined with the entirely implantable design, the rather high recording bandwidth, and the ability to record and stimulate simultaneously put forward a wireless BCI capable of long-term un-tethered real-time communication for causal preclinical circuit-based closed-loop interventions.

A model of inductive charging technique in battery electric vehicles(BEVs)

In this paper a prototype model has been designed. In this study a theoretical concept of a simple but effective method for inductive charging in battery electric vehicles(BEV) has been proposed. It has been observed in experimental study that power can be transferred wirelessly from transmitter to receiver using inductive coupling principles. In this article a prototype model has been designed to observe the inductive charging and also the inductive resonant coupling. It has also been observed experimentally that the power output of the wireless charging model significantly based on the resonant condition between the transmitting and receiving coils. In this article a proposed model has been presented to focus on the inductive coupling power transfer technique which is used for charging of a battery electric vehicles(BEVs). The proposed model and its experimental results successfully describes the inductive charging technique and the maximum power transfer occurs when resonant condition achieved by the two coils in very smaller distance. This model is very effective to established the concept of wireless power transfer in very smaller coil size. The experimental implementation of the design is made with digital multimeter, milliammeter, power-MOSFETS, voltage regulator IC, oscillator and diode rectifier circuit.in the transmitter and receiver coils.

Sounding observation of vertical electric field in eyewall of Typhoon Wipha (No. 1907) during landing period

In the summer of 2019, one case of electric field sounding in eyewall of No.1907 typhoon named Wipha was obtained in Wenchang, Hainan Island, China. Up to now, it has been the first case of electric field sounding results obtained in a typhoon system. In this paper, based on the observations of satellite, meteorological radar, ground electric field and cloud-to-ground flash location data of Hainan province, China, the basic characteristics of the typhoon are analyzed in detail. Owing to the limitation of cloud-to-ground flash location system, only flash activities of the typhoon before and after landing period are analyzed and the result does not show obvious features as reported by other researches. Referring to the radar reflectivity and sounding path, we confirm that the sounding penetrates through the eyewall region of the typhoon from cloud base to top. The electric field profile and the charge region distribution in the sounding path area are analyzed, and the results show that four positive and three negative charge regions exist between 5.74 and 9.10 km above sea level and the corresponding temperatures range from –2.4 to –16.7 ℃ of the seven charge regions. The mean charge densities of each charge region from bottom to top are 0.63 nC/m<sup>3</sup>, –0.33 nC/m<sup>3</sup>, 0.31 nC/m<sup>3</sup>, –1.03 nC/m<sup>3</sup>, 1.70 nC/m<sup>3</sup>, 1.57 nC/m<sup>3</sup> and –1.20 nC/m<sup>3</sup>, respectively. According to the preliminary analysis, we consider that the two positive charge layers at the top should be in the same charge region. Under the comprehensive consideration of the thickness of charge regions, the intensities of these six charge regions are 0.33 nC/m<sup>2</sup>, –0.07 nC/m<sup>2</sup>, 0.06 nC/m<sup>2</sup>, –0.87 nC/m<sup>2</sup>, 0.73 nC/m<sup>2</sup>, and –0.18 nC/m<sup>2</sup>, respectively. We can find that there are three dominant charge regions with largest intensity and they are the lowest positive charge region, the middle main negative region, and upper main positive charge region. And these vertical distributions of the three dominant charge regions are characterized by a tripole charge structure. These results are basically consistent with some simulation results. In addition, a negative screen charge region with a shallow depth in a range of 15–20 dBZ of the upper cloud boundary can be found. Combining the popular charging mechanisms, the similarity of tripole charge structure between our sounding and normal thunderstorm are discussed, and we preliminary consider that the non-inductive charging mechanism and the inductive charging mechanism, which originate from normal convection, are also suitable for eyewall region of typhoon.

A Measurement System for the Characterization of Wireless Charging Stations for Electric Vehicles

This article describes a new traceable measurement system, designed for the characterization of inductive charging stations for electric vehicles. This article particularly focuses on static charging (stationary vehicle), while dynamic charging (charging while driving) requires a significantly different system. The measurement system is able to measure on-site performance and efficiency of the charging station and converters. The relative uncertainty is ≤10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> . The measurement system aims at accurately measure the power at the batteries and the power transferred from the ground to the onboard resonant circuit and makes possible a benchmarking between station measuring systems. Finally, this measurement system allows the characterization of the magnetic emissions by correlating them with the electric current in the coils. This system improves the ease and ability to characterize wireless charging stations both in field and laboratory environments. This article describes in detail the hardware, the software, the GPS synchronization, and, in summary, the system architecture.

A Closely Coupled and Scalable High-Power Modular Inductive Charging System for Vehicles

For a high-power inductive charging solution that can be used on all types of vehicles, careful consideration must be made in all steps of the design process, including system architecture, coil geometry, and communications. Extensive studies on the effects of human exposure to electromagnetic fields (EMF) have identified recommended guidelines for electromagnetic limits in regions where humans or other living objects may frequent. Commercial wireless low power chargers today operating at 85 kHz and up to 11 kW are capable of meeting international EMF standards such as IEEE C95.1-2019. In this article, we address high-power wireless chargers designed for electrified light and heavy-duty vehicles such as buses and trucks that accept charging in hundreds of kilowatts. Laboratory studies of a modular 50–75-kW coupler confirm that leakage fields from one such module will meet U.S. and International EMF limits at the vehicle perimeter and beyond. In particular, a cluster of four such couplers operating at 65 kW each will not exceed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$27~\mu \text{T}$ </tex-math></inline-formula> adjacent to the vehicle, decaying at 1/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{r}^{3}$ </tex-math></inline-formula> or faster. The experimental results confirm simulation and show that fringing fields meet published standards in the vehicle cabin and beyond its perimeter when operating at 260 kW.

A Hybrid Charger of Conductive and Inductive Modes for Electric Vehicles

Electric vehicles (EVs) are gaining more and more user acceptances due to their clean, efficient, and environmentally friendly nature. Currently, most commercial EVs use conductive charging for their batteries. Inductive charging, which is an alternative charging technology, has recently received a great deal of attention because of its increased user convenience and safety. It is forecast that the two charging technologies will be implemented in future charging infrastructures globally. Consequently, future EVs need to be capable of dealing with both charging methods. So far, there have only been a very few charging topologies reported in the literature that describe both charging methods in the same vehicle. However, solutions that have been proposed do not show a significant component reduction. In this article, we propose a hybrid charger system where the high-frequency transformer of an onboard dc-dc converter becomes the coupling point between the conductive and inductive charging. Using this coupling point, the circuit utilizes the same components for conductive and for inductive charging. This results in the reduction of component count and, therefore, an improved integration. The proposed system is verified by both simulation and experiment. For the experiment, a 3-kW prototype has been built and tested. The maximum efficiency of 97.4% and 93.6% was achieved in the conductive and inductive mode, respectively.

Design and optimization of 3‐kW inductive power transfer charging system with compact asymmetric loosely coupled transformer for special applications

SummaryInductive power transfer (IPT) technology has become popular in wireless charging applications. Compared with the traditional 3‐kW wireless charging application, the diameter for the primary coil and the secondary coil in this special design are required to be smaller than 260 and 110 mm, respectively. In order to achieve this target, an approach to design and optimize the loosely coupled transformer (LCT) is proposed to match the strict geometry limitation, while achieving the high conversion efficiency. Different from the traditional design method, the low resonant current and voltage stress are considered as the input of the design flowchart, especially the LCT. Thus, the overall conversion efficiency can be improved. Based on series–series (S–S) compensation topology, the parameter range of the LCT is determined by analyzing transformer‐based equivalent model. To achieve the desired coil size, an asymmetric LCT with single‐layer primary coil and three‐layer secondary coil is designed and optimized by the proposed approach. Furthermore, the closed‐loop controller with narrow frequency variation range is design to realize constant current (CC) charge and constant voltage (CV) charge. A 3‐kW IPT charging prototype is built to demonstrate the validity of the proposed method. Experimental results show that the peak efficiency from input to battery load is 95.69% at 3‐kW output power in the transition point from CC mode to CV mode.

In-route inductive versus stationary conductive charging for shared automated electric vehicles: A university shuttle service

In-route inductive charging technology, as applied to automated electric vehicles, can help realize a fully automated system of both vehicles and chargers. This study presents a planning optimization analysis for fixed-route automated shuttles supported by in-route inductive charging technology. A techno-economic feasibility of inductive charging was assessed in comparison with stationary charging, including Level 2 AC chargers, and DC fast chargers (DCFCs). This analysis considered both present-day and future vehicle operations and overall system costs. A real project with two circulator Navya Arma shared automated electric vehicles (SAEVs) at the University of Michigan was investigated using real-world collected energy and travel data. The outcomes show that the proper design of quasi-dynamic inductive chargers at designated stops allows SAEVs to realize unlimited driving range and be cost-competitive to DCFC technology. Considering present-day costs and vehicles, low-speed SAEVs can realize charge-sustaining operation at a minimum cost either by implementing a 50-kW inductive charger at two stops with one segment per position and a 29-kWh onboard battery, or by installing a 100-kW inductive charger at one stop with one segment per position and a 28-kWh onboard battery. Considering future costs and vehicles, either a 40-kW charger at one stop with a 29-kWh battery or a 50-kW charger at the north stop with a 14-kWh battery would enable charge-sustaining operation. In addition, quasi-dynamic inductive solution can reduce the onboard battery by about 15% while providing unlimited driving range, but stationary scenarios require about 112% additional battery capacity to support a 12-h driving range.

Vehicle-to-grid technology and its suitability for the Moroccan national grid

Thanks to the technological advances in electronic devices and bidirectional power inverters, electric vehicles (EVs) are no longer viewed as just transportation tools. Rather, they could also serve as electric storage units for the grid and supply ancillary services within the framework of vehicle to grid (V2G) technology. Following the successful implementation of this emerging technology in several countries such as Germany and Spain, numerous scientific papers and research activities are addressing the use of V2G via plug-in cable energy transfer or inductive wireless charging. This paper investigates the suitability of such technology for the Moroccan national grid. It outlines the state of art of the V2G technology together with the current status of the country's power grid. Furthermore, the paper takes into consideration the evolution of the EV market in the country as well as the EV charging infrastructure deployed within its territories. Moreover, a survey on the services that the V2G could provide is presented. Finally, the authors conclude that the V2G would be very beneficial for the national power grid, providing up to 7.7 GW of controllable, and mobile loads by 2030, as well as for the EV owners once the recommended incentives are put in place.

Development of Visual Servoing-Based Autonomous Docking Capabilities in a Heterogeneous Swarm of Marine Robots

This paper describes the design, development, and testing of both hardware and software for a visual servoing-based system that enables agents within a heterogeneous marine robotic swarm to share energy. The goal of this system is prolonging the active operational time of the swarm as a whole, allowing it to perform long-term environmental monitoring and data collection missions. The implementation presented in the paper features an over-actuated autonomous surface platform docking up to four floating sensor nodes at a time and replenishing their batteries using wireless inductive charging. Mechanical solutions for each robot segment related to the docking procedure are presented, along with pertinent high-level and low-level control structures. A node featuring an extended Kalman filter and additional heuristics is used to fuse measurements from a neural network trained for object detection and a hue thresholding image processing algorithm, in order to track the docking target and achieve visual servoing. Finally, experimental results in both a controlled environment and challenging conditions on-site are presented. Once deployed, the developed system successfully enables the approach and docking of the designated target, showing its feasibility in different real-life conditions.

Charging processes during the dissipation stage of thunderstorms

Electric field and Maxwell current density measurements made below thunderstorms at Pune (India) have been analyzed to study the charging processes occurring during dissipation stage of thunderstorms. These observations suggest that during the dissipation stage of thunderstorm different charging processes contribute to the cloud electrification depending on the type of thunderstorms. Our observations suggest that updraft may not be sufficient to activate charging mechanism inside cloud during the dissipation stage in small thunderstorms. However, in big thunderstorms, non-inductive charging mechanism may be active during the dissipation stage. The recovery curves of electric field and Maxwell current density measured during dissipation stage of inverted polarity thunderstorms suggests that inductive charging mechanism may also contribute to the thunderstorm electrification.

Direct AC–AC Active-Clamped Half-Bridge Converter for Inductive Charging Applications

In this article, a new direct ac-ac active-clamped half-bridge converter feeding a series-series compensated inductive charging system is proposed. The proposed converter eliminates the rectification stage and bulky life-limited electrolytic dc-link capacitors, resulting in an actual single-stage (ac-to-ac) conversion with low component. The operation principles, steady-state analysis, and design considerations of the proposed converter are presented in detail. Moreover, a new predictive dead-beat technique for input current control and a linear average charging current controller are developed for the proposed converter, which enables the unity power factor and charging current regulation. The performance of the proposed battery charger is validated through experimental results on a 1-kW field programmable gate array (FPGA)-controlled silicon carbide based laboratory prototype.