Dynamic Inductive Power Transfer Research Articles

Low Power Dynamic and Asymmetric Inductive Wireless Power Transfer System to an Endoscopic Capsule

Low Power Dynamic and Asymmetric Inductive Wireless Power Transfer System to an Endoscopic Capsule

Enhancing Magnetic Coupling Using Auxiliary Short-Circuited Coils

The efficiency of Dynamic Inductive Power Transfer (DIPT) depends mainly on the coupling coefficient within the coupler. In order to improve this parameter, a novel approach has been introduced that results in a significant increase of between 25% and 36% at minimal additional cost in the case of juxtaposed rectangular coil configuration on the road. This method involves the incorporation of a passive additional short-circuit coil adjacent to the primary coil for obtaining a higher coupling coefficient, as has been theoretically demonstrated. Simulations carried out on Comsol have optimized the dimensions of this additional coil, not only for cost effectiveness and minimal space utilization, but also for optimal efficiency. Experimental validation was performed at reduced power, using a 2 kW test bench, and confirmed the estimation. The efficiency improvement proposed in this paper is crucial for improving the global DIPT efficiency and then facilitating its social acceptance.

Self-Oscillating Converter Based on Phase Tracking Closed Loop for a Dynamic IPT System

The coupling of converters with resonant networks poses significant challenges for frequency tracking and power control in inductive power transfer (IPT) systems. This paper presents an implementation method that addresses these issues by dividing the system’s operation into two distinct states: self-oscillating and power-injecting. Based on these states, a phase-closed loop is constructed. Within this closed loop, the phase tracking unit detects and tracks frequency drift, while the power regulating unit incorporates an integrator and adopts a control variable to adjust the output power by modifying the duration of the power injecting state. Meanwhile, the oscillating unit operates in the self-oscillating state. Operating in this manner, the system achieves self-oscillation and demonstrates the capability to effectively track and compensate for system variations within a single cycle. A verification prototype has been constructed, and it demonstrates that the converter within it completely decoupled from the resonant network. Experimental results validate that altering the control variable solely affects the duration of the power-injecting state, allowing for independent control of the output power. When the control variable changes from 2.0 V to 3.5 V, the output power changes from 178 W to 519 W while the self-oscillating state remains unchanged. Furthermore, the system accurately tracks frequency changes, even under significant variations in the coupling coefficient or load, without compromising the power injection state. When the air gap changes from 3 cm to 12 cm, the duration of the self-oscillating state changes from 22.1 μs to 26.3 μs, while the power injecting state remains unchanged. This approach exhibits a robust performance, particularly suitable for dynamic IPT systems sensitive to parameter variations.

50 kW Reflexive Tuning Networks With Low Uncoupled Transmitter Currents for Dynamic Inductive Power Transfer Systems

50 kW Reflexive Tuning Networks With Low Uncoupled Transmitter Currents for Dynamic Inductive Power Transfer Systems

Double-Coupling Resonant Network for Dynamic IPT Systems Used in EV Charging Applications

Dynamic inductive power transfer (DIPT) systems as well as static inductive power transfer (SIPT) systems are typically implemented with H-bridge inverters with resonant compensation networks to control and limit the charging current. However, contrary to SIPT, DIPT implies inherent displacements, in the travel direction, as well as the already expected misalignments (vertical and lateral). The challenges imposed by this feature have an impact on the selected compensation network. Typical single-coupling resonant topologies SS, SP, PS, PP, LCL-S and LCL-P are considered. In this work, a double-coupling SSS topology is proposed for DIPT applications to overcome the limitations of classical topologies. A resonant converter topology with natural current and voltage limitation under misalignment conditions is preferable. This paper performs a finite element analysis (FEA) simulation of the magnetic coupler (MC) in order to extract the coupling factor and self and mutual inductances as a function of the electric vehicle (EV) movement. The MC parameters are used to build a model in MATLAB/Simulink with coupling variation in order to assess the converter behavior under misalignment conditions. The simulation and experimental results demonstrate the applicability of the double-coupling SSS topology for DIPT application by exhibiting safe converter operation under the full range of coupling and load operation (full to no-coupling and full to no-load).

Modular Coupler With Integrated Planar Transformer for Wireless EV Charging

A dynamic inductive power transfer (IPT) system is a safe and convenient solution for providing power to electric vehicles (EVs) while they are driving along a roadway. This technology can help reduce the size and cost of the bulky EV batteries without limiting the EV's travelling range. In recent years, practical aspects of dynamic IPT systems have been investigated to advance various IPT technologies from laboratories into roadways. This paper suggest an IPT roadway layout, focusing on a modular IPT system configuration with an integrated semi-loosely coupled planar transformer inside the in-road coupler to mitigate the installation and maintenance concerns of IPT roadways. The proposed configuration keeps the current in the couplers constant and load-independent while providing galvanic isolation between the coupler and the converter, and can be used as a replacement for the conventional LCL and transformer configuration. In order to reduce the number of components used in each module, each in-road coupler is connected to a common H-bridge through a single DC switch to enable individual couplers to be energized independently. Mathematical analysis and simulation results are provided, and validated using a scaled 7.7 kW prototype IPT system employing the proposed configuration.

Auto-Segment Control System With High Spatially Average Power for Dynamic Inductive Power Transfer

This work proposes an auto-segment control system with multiple transmitters and dual receivers for dynamic inductive power transfer (DIPT) charging. The current of the transmitting coil precisely coupled with the receiver can be enhanced automatically, while the transmitting current will be suppressed when the transmitter is uncoupled with the receiver. Therefore, the electromagnetic interference (EMI) and power loss generated by uncoupled transmitters can be reduced without position detection and switching control. Each receiver includes a power coil and an impedance coil. When the vehicle moves along the road, the impedance coils are utilized to adjust the resonant state of the transmitter, and the power coils operate alternately to maintain a high spatially average power. The relative position and size between transmitters and receivers directly impact the power transfer performance. Therefore, several critical parameters of the magnetic coupler are analyzed and designed to obtain a considerable output power. An around 300W experimental prototype is established to verify the feasibility of the proposed magnetic coupler and design method. Compared to the auto-segment control system with a single receiver, the spatially average power of the proposed system is improved by twice, and the maximum efficiency is 84.9% in a moving period.

Quasi-stationary Approximation of Dynamic Inductive Wireless Power Transfer

Quasi-stationary Approximation of Dynamic Inductive Wireless Power Transfer

A Control Strategy to Avoid Drop and Inrush Currents during Transient Phases in a Multi-Transmitters DIPT System

Electrical Vehicles (EVs) have gained popularity in recent years in the automotive field. They are seen as a way to reduce the CO2 footprint of vehicles. Although EVs have witnessed significant advancement in recent years, they still have two major setbacks: limited autonomy and long recharging time. Dynamic Inductive Power Transfer (DIPT) systems permit charging EVs while driving, provide unlimited autonomy, and eliminate stationary charging time and lower battery dependency. Multiple transmitters are required to achieve DIPT; thus, dealing with transient phases is essential because every time a receiver crosses over from one transmitter to another, it experiences a new transient phase. This article presents a novel control strategy for multi-transmitter DIPT systems that ensures a continuous and stable power transfer to a moving EV. The proposed control strategy eliminates drop and inrush currents during transient phases. The control integrates a soft start feature and a degraded operating mode at a predefined maximum current value. The studied structure is a symmetrical series–series compensation network. Each transmitter coil is driven by a variable frequency inverter (around 85 kHz) to ensure Zero Phase Angle mode. The control strategy was numerically validated using MATLAB Simulink and then tested experimentally. Results show a relatively low power disruption after applying the proposed control during transmitter sequencing.

Fast Design Optimization Method Utilizing a Combination of Artificial Neural Networks and Genetic Algorithms for Dynamic Inductive Power Transfer Systems

Multiple parameters with large nonlinear characteristics must be considered simultaneously to design the coil dimensions of static inductive power transfer (SIPT) systems. The design of dynamic inductive power transfer (DIPT) systems is more challenging due to the large number of parameters needed to be considered. In the conventional artificial neural network (ANN)-based design approach, optimal coil dimensions are found using ANN that has learned the nonlinear characteristics between coil dimensions and magnetic characteristics using the finite element method (FEM). However, this approach requires a large amount of training data, and it is difficult to reach an optimum design if there are many design criteria. In order to overcome these challenges, this paper proposes a design optimization method using two approaches: improving the time efficiency of ANN training data collection by superposing the magnetic fields from the coils and improving the input value of ANN using a genetic algorithm. Design results predicted by the ANN are compared with FEM simulation, circuit simulations, and experimental results to verify the validity of the proposed algorithm. The FEM and circuit simulation results and the ANN prediction results match with errors of 10.2% or less for all design requirements. Experimental results are provided for a 3 <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> kW DIPT system with four transmitter coils and an automated test rail. Comparison results between ANN predicted values and experimental values match with an error of less than 12.7%.

Integrated Solution for Electric Vehicle and Foreign Object Detection in the Application of Dynamic Inductive Power Transfer

One of the challenges with the dynamic inductive power transfer (DIPT) technique is the electric vehicle detection (EVD) that helps the DIPT system to control the power supply of the transmitter. The EVD method applying auxiliary coils is a promising candidate because the flat shape of the auxiliary coils is suitable for the compact design. However, the EVD may fail when the metallic foreign object (MFO) is present. Therefore, the desire emerges in the integration design of the EVD and foreign object detection (FOD). The FOD can ensure the reliability of the EVD as well as the highly efficient operation of the DIPT system without MFOs. In this context, this paper proposes an integrated solution to the EVD and FOD well suited for DIPT systems. The integrated solution utilizes both passive coil sets (PCSs) and active coil sets (ACSs). Additionally, a novel detection resonant circuit (DRC) is proposed to realize EVD and FOD using the same coil sets and to amplify the measurement sensitivity. The operation mechanisms, the detection coil sets architecture, the design of the proposed resonant circuits and the detection procedure are detailed. Finally, a printed circuit board based prototype is built to validate the integrated functionality of the EVD and FOD in a DIPT prototype processing 1 kW output. Experiments considering the practical DIPT application scenarios are conducted, and the proposed detection method is able to achieve advantageously high sensitivity and no blind zone.

In-depth perception of dynamic inductive wireless power transfer development: a review

The emerging of inductive wireless power transfer (IWPT) technology provides more opportunities for the electric vehicle (EV) battery to have a better recharging process. With the development of IWPT technology, various way of wireless charging of the EV battery is proposed in order to find the best solution. To further understand the fundamentals of the IWPT system itself, an ample review is done. There are different ways of EV charging which are static charging (wired), static wireless charging (SWC) and dynamic wireless charging (DWC). The review starts with a brief comparison of static charging, SWC and DWC. Then, in detailed discussion on the fundamental concepts, related laws and equations that govern the IWPT principle are also included. In this review, the focus is more on the DWC with a little discussion on static charging and SWC to ensure in-depth understanding before one can do further research about the EV charging process. The in-depth perception regarding the development of DWC is elaborated together with the system architecture of the IWPT and DWC system and the different track versions of DWC, which is installable to the road lane.

An Inductive Coupler Array for In-Motion Wireless Charging of Electric Vehicles

An inductive power transfer (IPT) system is envisaged as the best solution to conveniently charge electric vehicles (EVs). While stationary IPT systems are becoming commercialized, significant research is being conducted to address the challenges related to dynamic IPT systems. Dynamic or in-motion IPT systems require a fully electrified roadway with embedded inductive couplers with accompanying circuitry. The large number of electronic components required, however, increases the system complexity, reducing the reliability and economic viability of dynamic IPT systems proposed to-date. This article proposes a simple yet robust push-pull driven coupler array (PPCA), aiming to decrease the number of switches required to drive the in-road couplers. This article is the first to report a configuration where only N+1 switches are required to independently energize N primary IPT couplers. Any number of couplers can be activated simultaneously in the array without proportionally increasing the current stress on the switches. A state-space model is developed and implemented in PLECS to investigate the efficiency and power transferred to an EV traveling over the proposed PPCA while considering the variation in the coupling and the self-inductances of the couplers. A 3.3-kW scaled prototype PPCA consisting of three primary couplers and two secondary couplers has been implemented to validate the performance of the proposed configuration.

Optimal Design of IPT Bipolar Power Pad for Roadway-Powered EV Charging Systems

This article proposes a multiobjective design optimization of rectangular bipolar power pads (BPP) for dynamic inductive power transfer (IPT) with application in electric vehicles. Minimization of IPT's design cost, loss that includes core and winding, and maximization of the IPT system's tolerance against horizontal/vertical misalignment are considered as objective functions during the optimization process. The design variables of the proposed algorithm are the shield plate length and width, ferrite bar length and width, the overlapping length of the coils, and the coil width and inner length of the coil. Power electronic limitations by defining the IPT's quality factor ( 4 <; Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> <; 10), maximum allowable electromagnetic field (EMF) exposure ( EMF ≤ EMF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Max</sub> ), efficiency of all possible solutions greater than 80% ( η > 80%), and upper/lower limits of design parameters are considered as the constraints of this optimization problem. The time-harmonic electromagnetic physics model of the BPP is analyzed using an finite element method magnetics (FEMM) software coupled with MATLAB. A nondominated genetic algorithm (NSGA-II) is employed as the optimization solver, in which the electromagnetic measurements from the FEMM software are used to evaluate the fitness values of the proposed objectives. The proposed BPP design optimization is applied on a 10-kW IPT system as a case study. The optimization results produced 15 Pareto optimal solutions. A validation study of two Pareto front solutions (PFS) is also presented. The Pareto optimal solutions allow the designer to select the best design parameters based on the objectives of highest priority.

Wireless Communication and Management System for E-Bike Dynamic Inductive Power Transfer Lanes

This paper presents the design, implementation, and testing of a wireless communication system for automatic identification of e-bikes and management of their battery charging in the context of dynamic inductive wireless power transfer (DIWPT) lanes. The proposed system checks if an e-bike, uniquely identified by its RFID tag, is authorized to receive energy from the lane coils and acts accordingly. An authentication mechanism was developed based on the use of embedded Wi-Fi boards attached to the coils and communicating with a central HTTP server with a MySQL database. The developed management system also provides other features, such as the recording of the number of lane coils used by each e-bike for billing purposes. The results from experimental tests on a laboratory prototype were used to validate the developed functionalities and assess the quality of service provided by the proposed system.

Dynamic Wireless Charging of Autonomous Vehicles: Small-scale demonstration of inductive power transfer as an enabling technology for self-sufficient energy supply

Recent developments toward selfdriving cars combined with technology for wireless inductive power transfer can enable electric vehicles that are fully autonomous with respect to operation and energy requirements. Furthermore, technology for wireless opportunity charging and dynamic on-road inductive power transfer can facilitate autonomous electric vehicles with unlimited driving range. This article discusses the technological progress toward self-driving vehicles and the potential capability for an autonomous energy supply enabled by dynamic on-road wireless power transfer.

The Fabric ICT Platform for Managing Wireless Dynamic Charging Road Lanes

As dynamic inductive power transfer for electric vehicles is growing in relevance, it is important to analyze solutions towards its deployment and integration in the cloud-based services for electric mobility. In this paper we present an Internet-enabling platform for Electric Vehicle Supply Equipment, which features a high-level Charging Station Control Unit and a Power Electronics Controller. The platform is a middleware that controls the charging process taking into account outside world information. Tests were performed in a safe driving track, in Italy, to verify the effectiveness and robustness of the installation, for one year, for a total of 120 drive hours, under various weather conditions. Tests showed the suitability of the platform in terms of ability to authenticate and authorize a vehicle even through a remote service, sequentially control each coil in a lane, monitor the charging process, assist the driver in keeping the vehicle aligned so as to maximize the energy exchange and deliver charging session information to the cloud (e.g. for billing).

Economic analysis of dynamic inductive power transfer roadway charging system under public-private partnership–Evidence from New Zealand

Electric vehicles (EVs) are contributing to a decarbonisation of conventional Internal Combustion Engines (ICEs) in the transport sector. With recent technological advancements in Dynamic Inductive Power Transfer (DIPT) system, EVs can be energised wirelessly by embedding a roadway charging network while travelling in-motion. However, the provision of a viable DIPT system still remains challenging, given the large-scaled investment required and some potential risks involved. This study assesses the economic viability of a DIPT system for EVs through public–private partnership (PPP), by employing a net present value (NPV) framework, to determine the optimal PPP ratio. The PPP model could be considered an effective pathway for leveraging capital, alleviating uncertainties associated with construction and operation, and achieving a nation's Sustainable Development Goals (SDGs). New Zealand is used as a real-world case study. Our results indicate that, for a 15-year concession period under PPP where the private investor is expecting a 12.5% return, the government can contribute 9.46% towards the initial investment and charging roadway users a toll of 37 cents/kWh. By implementing the DIPT system, EVs could achieve a significant reduction in carbon dioxide (CO2) emissions compared to ICEs. The robustness of the model is validated through Monto Carlo sensitivity analysis.

Particle Swarm Optimization-Based Parameter Design Method for S/CLC-Compensated IPT Systems Featuring High Tolerance to Misalignment and Load Variation

Inductive power transfer (IPT) systems designed with conventional methods offer optimum performance only at specific operational points. These methods are not applicable for dynamic IPT systems where both the coupling and load change throughout the operation. This study proposes a novel particle swarm optimization (PSO)-based parameter design method and aims to obtain a steady output voltage regardless of the coupling and load. The proposed method addresses the constraints of the conventional methods where the compensation capacitors/inductors are designed to resonate with certain other inductors/capacitors at the system's operational frequency. The S/ CLC (primary series, secondary capacitor–inductor–capacitor) compensation topology is chosen in this research as it offers many appealing characteristics. The procedure to design an IPT system using the proposed method is presented. Two IPT systems, one designed with the proposed scheme and the other using conventional methods, are theoretically and experimentally compared in terms of fitness, voltage variation ripple (VVR), and power transfer efficiency (PTE). It is demonstrated that the fitness and the VVR of the conventional system are 1400.8% and 372.3% higher than those of the proposed system.

Bifurcation Limits and Non-Idealities Effects in a Three-Phase Dynamic IPT System

Multi-phase dynamic inductive power transfer (D-IPT) systems are capable of achieving uniform power transmission with low control complexity and high efficiency. To achieve acceptable power capabilities, D-IPT systems have to work in resonance configurations. In contrast to transformers, and due to the low coupling coefficient, the compensation is carried out separately in the primary and secondary sides. Consequently, an effect known as bifurcation or pole splitting is created. This causes extra losses in the semiconductors because zero voltage switching (ZVS) is lost. The main objective of this paper is to derive the bifurcation limits for a three-phase D-IPT system. First, the meander coil configuration is introduced. Because this is a system with multiple variables, five assumptions are made to achieve closed-form equations. Therefore, the 36 inductance system is converted into an ideal three inductance problem. With these assumptions, the equations of the coupling, power, and inductance ratio limits are obtained. Afterward, the repercussion of these assumptions is analyzed using illustrations that depict the input impedance angle for various non-ideal conditions. Finally, a 9-kW prototype is used to validate the calculations, analyzing two different operating points: incomplete ZVS and complete ZVS.