Topic Editors

Dr. Yun Yang
Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
Power Electronics Research Centre, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China

Coil, Circuit and Control Designs for Future Wireless Power Transfer Systems in Electric Vehicle Applications

Abstract submission deadline
closed (15 February 2023)
Manuscript submission deadline
closed (31 May 2023)
Viewed by
23429

Topic Information

Dear Colleagues,

There is a global consensus to promote using Electric Vehicles (EVs) to replace traditional combustion vehicles in order to help combat climate change. The dawn of the EV era and subsequent self-driving systems have also prompted the urgent development of advanced self-commissioning wireless charging technologies. For mobile devices, such as automated guided vehicles, drones, lawnmowers, and vacuum cleaners, being charged with wireless power can save CO2 emissions and electronic waste due to higher energy utilization and less cable usage. Existing wireless charging standards, such as “Qi” and “Rezence”, are set for 5 W to 200 W low-power applications with one-dimensional planar coils. These standards need to evolve with new wireless power transfer (WPT) technologies for emerging medium-power and high-power applications with a larger spatial freedom because 1% improvements of energy transfer efficiency, charging time, and lifecycles may be negligible for low-power applications but lead to carbon reduction in high-power applications.

This topic hopes to bridge this knowledge gap by compiling a series of new control technologies of coil, circuit, and control designs for emerging EV applications, which have great potential to be included in next-generation wireless charging standards. Taking advantage of these technological developments, the outcomes of this project will facilitate the large-scale adoption of wireless-powered EVs, which will help reduce CO2 emissions and electronic waste.

Dr. Yun Yang
Prof. Dr. Ka Wai Eric Cheng
Topic Editors

Keywords

  • electric vehicle;
  • wireless power transfer;
  • coil design;
  • power converters;
  • control

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Applied Sciences
applsci
2.7 4.5 2011 16.9 Days CHF 2400
Electronics
electronics
2.9 4.7 2012 15.6 Days CHF 2400
Energies
energies
3.2 5.5 2008 16.1 Days CHF 2600
Journal of Low Power Electronics and Applications
jlpea
2.1 3.1 2011 22.2 Days CHF 1800
World Electric Vehicle Journal
wevj
2.3 3.7 2007 14.1 Days CHF 1400
Electricity
electricity
- - 2020 20.3 Days CHF 1000
Chips
chips
- - 2022 15.0 days * CHF 1000

* Median value for all MDPI journals in the second half of 2023.


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Published Papers (13 papers)

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19 pages, 4331 KiB  
Article
Simulation and Control Design of a Midrange WPT Charging System for In-Flight Drones
by Oussama Allama, Mohamed Hadi Habaebi, Sheroz Khan, Md. Rafiqul Islam and Abdullah Alghaihab
Energies 2023, 16(15), 5746; https://doi.org/10.3390/en16155746 - 01 Aug 2023
Cited by 2 | Viewed by 1085
Abstract
Drones, or unmanned aerial vehicles (UAVs), have emerged as an indispensable tool across numerous industries due to their remarkable versatility, efficiency, and capabilities. Notwithstanding all these traits, drones are still limited by battery life. In this paper, we propose a genuine in-flight charging [...] Read more.
Drones, or unmanned aerial vehicles (UAVs), have emerged as an indispensable tool across numerous industries due to their remarkable versatility, efficiency, and capabilities. Notwithstanding all these traits, drones are still limited by battery life. In this paper, we propose a genuine in-flight charging method without landing. The charging system consists of three orthogonal coils, among which the receiving coil is connected to the drone. The development of the model for wireless dynamic charging systems is achieved by integrating the receiver trajectory and velocity in the model. Furthermore, the model is significantly enhanced by introducing the concept of the positioning mutual coupling function for the receiver trajectory; thus, it is possible to simulate a genuine continuous trajectory for UAVs and link it to the systems’ total input power consumption. The developed control algorithm can direct the magnetic field resultant to track the exact trajectory of the drone. The real-time simulation of the multiparameter discrete extremum-seeking control (ESC) algorithm on the (DSP) F28379D hardware shows that the input power is maximized up to 12 W in a response time of 2 ms for a drone-hovering velocity of 8 m/s without any feedback. Full article
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20 pages, 8677 KiB  
Article
A Six-Switch Mode Decoupled Wireless Power Transfer System with Dynamic Parameter Self-Adaption
by Wei Wu, Daqing Luo, Jianfeng Hong, Zhe Tang and Wenxiang Chen
Electronics 2023, 12(10), 2314; https://doi.org/10.3390/electronics12102314 - 20 May 2023
Cited by 1 | Viewed by 1022
Abstract
For the fully resonant wireless power transfer (WPT) system, the high coupling of the converter and the resonant network introduced many problems, such as frequency splitting, the power curve peak limit, and the strict switch strategy. To solve these problems, this paper proposed [...] Read more.
For the fully resonant wireless power transfer (WPT) system, the high coupling of the converter and the resonant network introduced many problems, such as frequency splitting, the power curve peak limit, and the strict switch strategy. To solve these problems, this paper proposed a new six-switch topology based on the full–-bridge converter. With the unique structures containing two capacitor-isolated switches and a source-isolated diode, the system decouples the converter and the resonant network, and its modes have been decoupled, called the independent power injection and free resonance WPT (IPIFR–WPT) system. The capacitor-isolated switches and the source-isolated diode make the converter operate only when the voltage on the primary capacitor is equal to the source voltage, and the source will be isolated by the diode when the capacitor voltage is great than the source, which provides a wide time margin for the switches of the converter to turn on in advance. In this margin, the operation point is self-determined the same whenever the switches turn on so that the system’s performance is consistent. Based on this characteristic, the system can self-adapt a dynamic change in system parameters, with at least 15% tolerance for the coupling coefficient and 14% for the load resistance. Full article
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23 pages, 4898 KiB  
Article
SPWM Inverter Control for Wireless Constant Current and Voltage Charging
by Kang Sun and Wangqiang Niu
World Electr. Veh. J. 2023, 14(4), 111; https://doi.org/10.3390/wevj14040111 - 14 Apr 2023
Cited by 2 | Viewed by 2701
Abstract
Constant current (CC) and constant voltage (CV) charging of batteries is a crucial research area in the practical implementation of wireless power transfer (WPT) systems. The typical charging process of a battery starts from the constant current mode. As the battery’s voltage increases, [...] Read more.
Constant current (CC) and constant voltage (CV) charging of batteries is a crucial research area in the practical implementation of wireless power transfer (WPT) systems. The typical charging process of a battery starts from the constant current mode. As the battery’s voltage increases, the charging mode switches to the constant voltage mode. During charging, the equivalent load resistance of the battery will vary with the charging time, and the equivalent load resistance will affect the charging current or voltage and system’s efficiency. In this study, an adaptive wireless charging method of CC-CV is proposed based on sinusoidal pulse width modulation (SPWM) inverter control. The proposed WPT circuit detects the load variation by measuring the parameters of load voltage and load current, and accurately controls the system output current or voltage by adjusting the modulation depth of the SPWM inverter on the primary side. When there is relative motion between the transmitting coil and the receiving coil, the sharp change in coupling coefficient directly affects the system’s output voltage and output current, leading to output fluctuations and instability. To solve this problem, a method for estimating the coupling coefficient is proposed which estimates the coupling coefficient during the charging process by measuring system parameters. Then, the controller on the primary side adjusts the modulation depth of the SPWM inverter circuit based on the estimated new coupling coefficient, so that the system can still achieve constant current and constant voltage charging under displacement or distance changes. In this study, the CC mode output current during battery charging was set to 0.75 A, and the CV mode output voltage was set to 12 V. Simulation and experimental results demonstrate the validity and accuracy of the proposed control method. Full article
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16 pages, 8620 KiB  
Article
The Effect of Boost Coil and Alignment of Transmitting and Receiving Coils on Transmission Efficiency in EV Wireless Power Transfer Systems
by Young-Kuk Choi, Don-Jung Lee and Sung-Jun Park
Energies 2023, 16(7), 3213; https://doi.org/10.3390/en16073213 - 03 Apr 2023
Cited by 1 | Viewed by 1736
Abstract
As the electric vehicle (EV) market continues to grow, wireless charging technologies are constantly evolving. Considering the limitations of traditional charging methods, the adoption of wireless charging technology is an essential strategy, and the distribution of wireless charging systems is expected to accelerate [...] Read more.
As the electric vehicle (EV) market continues to grow, wireless charging technologies are constantly evolving. Considering the limitations of traditional charging methods, the adoption of wireless charging technology is an essential strategy, and the distribution of wireless charging systems is expected to accelerate in the global market with initiatives such as international standards for wireless charging systems. With regard to this technological trend, this study experimentally analyzed the effects of the boost coil and the alignment of the transmitting and receiving coils on the transmission efficiency in wireless power transfer systems. The boost coil amplifies the magnetic field using a high-frequency signal and transfers the field to the receiving coil. Moreover, simulations were conducted based on the theory that using the boost coil could increase the efficiency of wireless power transfer, and the impact of the alignment between the transmitting and receiving coils on the transmission efficiency was also analyzed. Full article
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42 pages, 18330 KiB  
Review
Inductive Wireless Power Transfer Systems for Low-Voltage and High-Current Electric Mobility Applications: Review and Design Example
by Manh Tuan Tran, Sarath Thekkan, Hakan Polat, Dai-Duong Tran, Mohamed El Baghdadi and Omar Hegazy
Energies 2023, 16(7), 2953; https://doi.org/10.3390/en16072953 - 23 Mar 2023
Cited by 7 | Viewed by 3510
Abstract
Along with the technology boom regarding electric vehicles such as lithium-ion batteries, electric motors, and plug-in charging systems, inductive power transfer (IPT) systems have gained more attention from academia and industry in recent years. This article presents a review of the state-of-the-art development [...] Read more.
Along with the technology boom regarding electric vehicles such as lithium-ion batteries, electric motors, and plug-in charging systems, inductive power transfer (IPT) systems have gained more attention from academia and industry in recent years. This article presents a review of the state-of-the-art development of IPT systems, with a focus on low-voltage and high-current electric mobility applications. The fundamental theory, compensation topologies, magnetic coupling structures, power electronic architectures, and control methods are discussed and further considered in terms of several aspects, including efficiency, coil misalignments, and output regulation capability. A 3D finite element software (Ansys Maxwell) is used to validate the magnetic coupler performance. In addition, a 2.5 kW 400/48 V IPT system is proposed to address the challenges of low-voltage and high-current wireless charging systems. In this design, an asymmetrical double-sided LCC compensation topology and a passive current balancing method are proposed to provide excellent current sharing capability in the dual-receiver structures under both resonant component mismatch and misalignment conditions. Finally, the performance of the proposed method is verified by MATLAB/PSIM simulation results. Full article
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16 pages, 1600 KiB  
Article
A Position-Insensitive Nonlinear Inductive Power Transfer System Employing Saturable Inductor
by Xu Yang, Junfeng Yang, Jing Fan, Bao Wang and Dingzhen Li
Energies 2023, 16(5), 2430; https://doi.org/10.3390/en16052430 - 03 Mar 2023
Cited by 1 | Viewed by 1118
Abstract
Most of the practical inductive power transfer (IPT) systems are the ones with variable coupling coefficients and loads. The output voltage, current and power are affected by the variation in coupling coefficient and load. In this paper, a novel approach based on a [...] Read more.
Most of the practical inductive power transfer (IPT) systems are the ones with variable coupling coefficients and loads. The output voltage, current and power are affected by the variation in coupling coefficient and load. In this paper, a novel approach based on a nonlinear resonator is proposed to obtain stable output voltage, which is independent of coupling coefficient and load variation. First, the theory and properties of nonlinear resonators are analyzed by Duffing equation. Then, a nonlinear IPT system with a magnetic saturation inductor is proposed, and the saturable inductor modeling and its effect on system performance are further studied. Finally, the experimental prototype is built to validate the effectiveness of the nonlinear IPT system. The experimental results show that when the coupling coefficient varies from 0.32 to 0.24 and the load resistance varies from 80Ω to 120Ω, the system works in a nonlinear state, the output voltage ripple is 1.77%, and the overall efficiency of the system is not less than 82.60%. The experimental results are basically consistent with the theoretical analysis. The novel design approach improves the output voltage stability with respect to position misalignment and load variation, and the bandwidth of the system is also enhanced. Full article
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17 pages, 7346 KiB  
Article
A Magnetic Field Containment Method for an IPT System with Multiple Transmitting Coils Based on Reflective Properties
by Xu Yang, Junfeng Yang, Jing Fan, Bao Wang and Dingzhen Li
Electronics 2023, 12(3), 653; https://doi.org/10.3390/electronics12030653 - 28 Jan 2023
Cited by 2 | Viewed by 1235
Abstract
Inductive power transfer (IPT) systems with multiple transmitting coils are mainly used in specific scenarios, such as IPT sharing platforms and dynamic wireless charging of electric vehicles, etc. However, it faces problems of electromagnetic field leakage and low efficiency. A new magnetic field [...] Read more.
Inductive power transfer (IPT) systems with multiple transmitting coils are mainly used in specific scenarios, such as IPT sharing platforms and dynamic wireless charging of electric vehicles, etc. However, it faces problems of electromagnetic field leakage and low efficiency. A new magnetic field containment method based on reflective properties is proposed to solve the above shortcomings. Firstly, the reflective properties and performance figures of the IPT system with a unified passive compensation network are described and derived. Then, an S−LCL topology appropriate for the time−varying coupling IPT system is presented, where the IPT system’s transmitter consists of multiple coils that are compatible with one or more moving receivers and is powered by an inverter. Then, magnetic field focusing, power transfer and overall efficiency are analyzed and simulated. Finally, an experimental prototype is built to validate the feasibility of the proposed system. The experimental results show that the proposed method can increase the power transfer of the coupled transmitting coil and reduce the magnetic field leakage of the standby transmitting coils without complex shielding measures, switch, position detection and communication circuits. Full article
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21 pages, 9952 KiB  
Article
An Auxiliary Passive Circuit and Control Design for Wireless Power Transfer Systems in DC Microgrids with Zero Voltage Switching and Accurate Output Regulations
by Hu Xiong, Bin Xiang and Yuan Mao
Energies 2023, 16(2), 694; https://doi.org/10.3390/en16020694 - 06 Jan 2023
Viewed by 1151
Abstract
This paper presents an auxiliary passive circuit and control design for wireless power transfer (WPT) systems in DC microgrids to achieve optimal power transfer efficiency while maintain accurate output voltage regulation. An auxiliary inductance is added at the transmitter resonator to form a [...] Read more.
This paper presents an auxiliary passive circuit and control design for wireless power transfer (WPT) systems in DC microgrids to achieve optimal power transfer efficiency while maintain accurate output voltage regulation. An auxiliary inductance is added at the transmitter resonator to form a current sink to ensure zero voltage switching (ZVS) of the primary-side full-bridge inverter with even extremely light load conditions. Moreover, an adaptive proportional–integral (PI) controller is adopted to track the output voltage references by regulating the phase shift angle of the phase shift control for the full-bridge inverter. The coefficients of the adaptive PI controller are determined by the inductance of the auxiliary inductance. Both simulation and experimental results validated the effectiveness of the proposed circuit and control design in achieving optimal efficiency and output voltage regulation for WPT systems in DC microgrids with source and load variations. Full article
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21 pages, 3063 KiB  
Article
Aspects of Foreign Object Detection in a Wireless Charging System for Electric Vehicles Using Passive Inductive Sensors
by Uwe Hentschel, Fiete Labitzke, Martin Helwig, Anja Winkler and Niels Modler
World Electr. Veh. J. 2022, 13(12), 241; https://doi.org/10.3390/wevj13120241 - 15 Dec 2022
Cited by 2 | Viewed by 2083
Abstract
If the energy transfer for charging the traction battery of an electric vehicle takes place wirelessly and with inductive components, the active area of the charging system must be monitored for safety reasons for the presence or intrusion of metallic objects that do [...] Read more.
If the energy transfer for charging the traction battery of an electric vehicle takes place wirelessly and with inductive components, the active area of the charging system must be monitored for safety reasons for the presence or intrusion of metallic objects that do not belong to the charging system. In the past, different concepts for such monitoring have been described. In this paper, passive inductive sensors are used and characterized based on practical measurements. With this type of sensor, the detectability of metallic foreign objects is very closely related to the characteristics of the magnetic field of the charging system. By optimizing the geometry of the sensor coils, the authors show how foreign object detection can be improved even in areas with low excitation of the foreign objects and the sensor coils by the magnetic field. For this purpose, a charging system, with which charging powers of up to 10 kW have been realized in the past, and standardized test objects are used. Furthermore, the thermal behavior of the metallic test objects was documented, which in some cases heated up to about 300 °C and above in a few minutes in the magnetic field of the charging system. The results show the capability of passive inductive sensors to detect metallic foreign objects. Based on the measurements shown here, the next step will be to simulate the charging system and the foreign object detection in order to establish the basis for a virtual development and validation of such systems. Full article
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13 pages, 5468 KiB  
Article
Design of LCC-P Constant Current Topology Parameters for AUV Wireless Power Transfer
by Kangheng Qiao, Enguo Rong, Pan Sun, Xiaochen Zhang and Jun Sun
Energies 2022, 15(14), 5249; https://doi.org/10.3390/en15145249 - 20 Jul 2022
Cited by 2 | Viewed by 1396
Abstract
The wireless power transmission (WPT) of an autonomous underwater vehicle (AUV) tends to have non-negligible eddy current loss with increasing frequency or coil current due to the conductivity of seawater. In this paper, the inductor-capacitor-capacitor and parallel (LCC-P) topology and the magnetic coupler [...] Read more.
The wireless power transmission (WPT) of an autonomous underwater vehicle (AUV) tends to have non-negligible eddy current loss with increasing frequency or coil current due to the conductivity of seawater. In this paper, the inductor-capacitor-capacitor and parallel (LCC-P) topology and the magnetic coupler with an H-shaped receiver structure are chosen to achieve a compact system on the receiving side. The conditions for constant current output of the LCC-P topology are analyzed based on the cascaded circuit analysis method. The traditional parameter design method does not consider the influence of eddy current loss on the system circuit model, by introducing the equivalent eddy current loss resistance at both the transmitting side and receiving side, a modified circuit model of the WPT system in the seawater condition was obtained. Afterward, a nonlinear programming model with the optimal efficiency of the constant current mode as the objective function is established, and the genetic algorithm is used to obtain the optimal system parameters. An underwater AUV-WPT prototype was built and the finite element simulation and experimental results verified the theoretical analysis. Full article
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11 pages, 4705 KiB  
Article
Research on Optimization of Horizontal Omnidirectional Misalignment Tolerance of WPT Based on Double D Coupler
by Fuhai Chi, Pan Wang, Chenglong Sun, Yuming Wu, Zhenlan Dou, Chenjin Xu, Shuo Wang and Wei Wang
Electronics 2022, 11(14), 2163; https://doi.org/10.3390/electronics11142163 - 11 Jul 2022
Cited by 1 | Viewed by 1259
Abstract
DD (Double D) coils have been researched and utilized due to their excellent misalignment tolerance. Here, a compound DD coupler sets for stationary wireless power chargers, which has significantly better anti-misalignment performance than single DD coupler in all directions, is proposed. The transmitting [...] Read more.
DD (Double D) coils have been researched and utilized due to their excellent misalignment tolerance. Here, a compound DD coupler sets for stationary wireless power chargers, which has significantly better anti-misalignment performance than single DD coupler in all directions, is proposed. The transmitting coils are composed of two parts of DD coils wound in opposite directions. Moreover, to obtain the low-level variation of mutual inductance between compound transmitting coils and receiving coils when offset occurs, a parameter optimization strategy of compensation coils is also proposed. With the properly designed parameters, the mutual inductance between transmitting and receiving coils could remain basically constant when misalignment occurs, which means that the efficiency and power remain relatively constant when offset occurs. Finally, both single DD coils and compound DD coils experimental prototypes are built to compare anti-misalignment ability performance. The results show that the proposed system is basically more stable and has a higher output power and more stable efficiency than that of unoptimized coupler during migration. In particular, with the employment of the antiparallel winding, the efficiency fluctuates from 85.5% to 85% when the 0.1-m offset in the X-axis and Y-axis occurs simultaneously. Moreover, the higher and basically more stable output power is also achieved. Full article
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17 pages, 8545 KiB  
Article
Wireless Charging Concave Coil Design for UAVs
by Langtao Yu, Li Wu, Yuyu Zhu, Xin Cao, Guozheng Zhang and Shicheng Xiang
Electronics 2022, 11(13), 1962; https://doi.org/10.3390/electronics11131962 - 23 Jun 2022
Cited by 3 | Viewed by 1590
Abstract
This paper proposes an orthogonal concave coupling mechanism based on wireless charging for unmanned aerial vehicles (UAVs); the original edge adopts a concave transmitting coil. So as not to occupy the gimbal position at the receiving end, the receiving coil is installed on [...] Read more.
This paper proposes an orthogonal concave coupling mechanism based on wireless charging for unmanned aerial vehicles (UAVs); the original edge adopts a concave transmitting coil. So as not to occupy the gimbal position at the receiving end, the receiving coil is installed on the landing gear of the UAV perpendicular to the transmitting coil to form an orthogonal coupling magnetic field. This study conducted a finite element simulation of the coupling mechanism using Ansys Maxwell to test the mechanism’s coupling capability and anti-offset performance. The spatial distribution of the system’s magnetic field was constrained, and the magnetic flux leakage of the system was reduced by optimizing the transmitter structure. The system employed a double-sided LCC compensation topology network and used wireless communication to achieve constant voltage/constant current closed-loop control. Finally, the experimental platform was built, and the results show that the system output power was able to reach 960 W with 85.7% efficiency, and could realize the closed-loop control of charging with 48 V constant voltage and 20 A constant current. The system has the advantages of being small in size, lightweight (290 g) and easy to install, and the receiver device has strong resistance to offset. Full article
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25 pages, 11780 KiB  
Article
A Constant Current Wireless Power Transfer Scheme with Asymmetric Loosely Coupled Transformer for Electric Forklift
by Xuecheng Liu, Jing Zhou, Aixi Yang, Jian Gao and Qiang Li
Electronics 2022, 11(12), 1845; https://doi.org/10.3390/electronics11121845 - 10 Jun 2022
Viewed by 1553
Abstract
Due to the numerous advantages such as being convenient, safe, and contactless, wireless power transfer (WPT) is becoming the mainstream charging method for electric vehicles. This paper presents a constant current WPT system with asymmetric loosely coupled transformer for electric forklifts using lead-acid [...] Read more.
Due to the numerous advantages such as being convenient, safe, and contactless, wireless power transfer (WPT) is becoming the mainstream charging method for electric vehicles. This paper presents a constant current WPT system with asymmetric loosely coupled transformer for electric forklifts using lead-acid batteries. First, based on the Neumann formula, this paper analyzes the mutual inductance of the coaxial rectangular coil, and designs an asymmetric loosely coupled transformer based on the practical application requirements, which makes the secondary side light and miniaturized. Second, the WPT system is analyzed in terms of the requirements of constant current charging, and the dual-LCL compensation is proposed according to the output current and power requirements. The transfer characteristics and anti-interference capability of the topology are analyzed. The constant current output feature of the system under the condition of variable load is demonstrated. After that, a dual-active bridge secondary-side independent control strategy is proposed, the phase shift angle is adjusted to ensure constant charging current and high efficiency of the system. Finally, a wireless charging experimental platform is established in accordance with the proposed asymmetric loosely coupled transformer and WPT system. The system can achieve 45 A constant current output and 3 kW output power with 91.2% transmission efficiency. Full article
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