Publications

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Near Field Electromagnetic Energy Flow Regulation Method for WPT System via Frequency Adjustment

Published in IEEE Journal of Emerging and Selected Topics in Power Electronics, 2024

A near-field wireless power transfer (WPT) system may simultaneously contains magnetic field coupled power (MFCP) and electric field coupled power (EFCP), and the comprehensive utilization of the two types of coupled power in space can help improve the power transfer capability and efficiency under misaligned conditions. This would help improve the grid interaction capabilities of electric equipment with near-field WPT systems to tackle the challenges posed by the integration of large-scale WPT systems to the power grid. From the electromagnetic energy flow theory based on Poynting vector analysis, this paper describes the energy flow process of the near-field WPT system under the effect of distributed parameters and obtains a reduced-order evaluation method to assess the transmission levels of the two types of coupled power……

Recommended citation: Fengxian Wang, Qingxin Yang*, Xian Zhang*, Ting Chen, Guangyao Li. Near Field Electromagnetic Energy Flow Regulation Method for WPT System via Frequency Adjustment. IEEE Journal of Emerging and Selected Topics in Power Electronics. Early Access.
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Enhancing Misalignment Tolerance in Hybrid Wireless Power Transfer System With Integrated Coupler via Frequency Tuning

Published in IEEE Transactions on Power Electronics, 2024

To enhance the misalignment tolerance and system integration of the wireless power transfer (WPT) system, an integrated coupler consisting of capacitors and coils overlapped coaxially is proposed in this article and integrated into the hybrid WPT (HWPT) system without extra compensation components. The system utilizes the complementary characteristics of different transmission channels to realize the synergistic transfer of different coupled powers under a wide coupling range. Based on the mutual influence between capacitors and coils in terms of electrical parameters in a limited axial projection area and the zero-phase-angle condition considering the mutual capacitance obtained by the fundamental harmonics approximation method, the method of regulating the transfer ratio of the two types of coupled powers is mastered. A method to……

Recommended citation: Fengxian Wang, Qingxin Yang*, Xian Zhang*, Ting Chen, Guangyao Li. Enhancing Misalignment Tolerance in Hybrid Wireless Power Transfer System With Integrated Coupler via Frequency Tuning. IEEE Transactions on Power Electronics. 39(9).
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A-High Efficiency Underwater Hybrid Wireless Power Transfer System with Low Plate Voltage Stresses

Published in IEEE Transactions on Power Electronics, 2024

This paper proposes a high-efficiency underwater hybrid wireless power transfer (UHWPT) system with low plate voltage stresses to ensure a safe and stable power supply for underwater electrical equipment. The power transfer channel is constituted by an integrated magnetic-electric coupler, formed by nesting coils into C-shaped plates and integrating them into the LC-compensated topology. The impact of the geometric dimensions and insulation on electrical parameters is explored to provide a reference basis for designing the integrated magnetic-electric coupler. A system design method based on the double optimization parameters is hereby proposed. Then, an experimental prototype is set up to verify the feasibility of the design method. Experimental results show that the system achieves the load-independent constant current (CC) output with a maximum efficiency of 87.8%.

Recommended citation: Xian Zhang, Guangyao Li, Ting Chen, Fengxian Wang*, Qingxin Yang, Weida Xu. A High-Efficiency Underwater Hybrid Wireless Power Transfer System with Low Plate Voltage Stresses. IEEE Transactions on Power Electronics. Early Access.
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Research on Energy Harvesting Method Without Blind Spots for a Two-dimensional Omni-directional Wireless Power Transfer System With Integrated LCC-S Topology

Published in Proceedings of the CSEE, 2023

This paper proposes a method for capturing wireless power in a two-dimensional omnidirectional manner without blind spots by integrating the LCC-S topology. The approach addresses the competition between spatial magnetic field integrity and the complexity of current control strategies in two-dimensional omnidirectional wireless power transfer technology. The system uses two-dimensional orthogonal coils as electromagnetic coupling mechanisms and integrates them into the LCC-S compensation topology. The magnetic field distribution in the system in two-dimensional space is analyzed using a field-road coupling finite element model, and the peak magnetic field intensity vector trajectory over time is circular. An integrated two-dimensional omnidirectional wireless power transfer experimental prototype was constructed, and experimental results demonstrate that the system achieves two-dimensional omnidirectional electromagnetic energy capture without blind spots under a single power source drive.

Recommended citation: Xian Zhang, Ran Wang, Fengxian Wang*, Chaoyang Yuan, Mousong Li, Qingxin Yang, Zhongyu Dai. Research on Energy Harvesting Method Without Blind Spots for a Two-dimensional Omni-directional Wireless Power Transfer System With Integrated LCC-S Topology. Proceedings of the CSEE. 44(10).
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Research on Self-Decoupling Segmented Coil Rail and Dual-Mode Switching Strategy of Dynamic Wireless Charging System

Published in Proceedings of the CSEE, 2023

In this paper, a dynamic wireless charging system for electric vehicles with self-decoupling segmented transmitter coils is presented. To this end, based on the naturally decoupling orthogonal solenoid and square coils, the solenoid and square coils are hierarchically connected in series to form the transmitter coil, eliminating the cross-coupling effects of the adjacent transmitter coils on the design of the compensation topology. To obtain a stable charging performance, a two-mode working method, where one or two transmitter coils are activated, is proposed based on the optimal charging area. A solenoid-detecting coil orthogonal wounded on the receiver coil is designed to detect the position of the receiver. The natural decoupling feature avoids the interference between the detection signal and power delivery. The performance and effectiveness of the proposed design are evaluated based on a scaled-down prototype. The experimental results show that the stability of the system output power is improved by 19.5%, and the maximum efficiency of the system can reach 92.3%.

Recommended citation: Xian Zhang, Weida Xu, Fengxian Wang*, Chaoyang Yuan, Qingxin Yang, Zhongyu Dai. Research on Self-Decoupling Segmented Coil Rail and Dual-Mode Switching Strategy of Dynamic Wireless Charging System. Proceedings of the CSEE. Early Access.
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Optimizing Levitation Devices for Wireless Power Transfer An Fe-NCS Grid Structure Approach

Published in IEEE Transactions on Power Electronics, 2023

This article proposes a solution for driving a microdisplacement device in the coupling space of a wireless power transfer system. The solution involves using a levitation device made of a combination of Fe-based nanocrystalline alloys (Fe-NCS) and aluminium. The dynamic model of the levitation device is analyzed to understand the electromagnetic force involved, and an optimized grid-type Fe-NCS structure is proposed to reduce the weight of the device and achieve stable levitation. The optimization uses a variable acceleration particle swarm optimization algorithm. A 3.7-kW prototype with 100-A input current is built to validate the proposed structure, and the results show that the optimized grid-type structure effectively enhances the average horizontal velocity of the levitation drive to 9.3 cm/s.

Recommended citation: Fengxian Wang, Qingxin Yang, Xian Zhang, Zhaoyang Yuan, Xuejing Ni. Optimizing Levitation Devices for Wireless Power Transfer An Fe-NCS Grid Structure Approach. IEEE Transactions on Power Electronics. 38(10).
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Electromagnetic Force Suppression of the Coupling Mechanism Structure of WPT System Based on Phase Difference Control

Published in Transactions of China Electrotechnical Society, 2021

The wireless power transmission system operating in the high-frequency electromagnetic field environment is subjected to electromagnetic force, and the long-term action will cause damage to the magnetic shield structure, coil deformation, and insulation damage. This article is about weakening the influence of structure electromagnetic force on the coupling mechanism of wireless power transmission system. First, analyze the structural electromagnetic force characteristics of the coupling mechanism of the wireless power transmission system from the perspective of frequency domain, and determine the relationship between the structural electromagnetic force characteristics and the phase of the current flowing through the coupling coil. Second, a structural electromagnetic force suppression scheme based on phase difference control is proposed. Using a two-wire parallel coupling structure, by adjusting the inductance of the adjustable branch connected in series to a certain transmitting coil branch, the phase of the current flowing through the coupling coil can be adjusted.Finally, the macroscopic force performance of the coupling mechanism is weakened. At the same time,an experimental platform was built to verify the effectiveness of the method.

Recommended citation: Fengxian Wang, Xian Zhang, Qingxin Yang, Lin Sha, Nianzhen Ren, Zhiyuan Fu. Electromagnetic Force Suppression of the Coupling Mechanism Structure of WPT System Based on Phase Difference Control. Transactions of China Electrotechnical Society. 37(01).
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Structure Electromagnetic Force Analysis of WPT System Under Fault Conditions

Published in IEEE Access, 2020

In the high-frequency electromagnetic field, the coupling of the wireless power transfer (WPT) system is affected by the electromagnetic force (EMF). The fault conditions will strengthen the influence, cause the damage of magnetic shielding structure, coil deformation, insulation damage and so on. In order to ensure the safe and stable operation of the WPT system, it is necessary to study the local EMF distribution of the coupling mechanism under the fault condition of WPT system. In this paper, the series to series (SS) compensation structure is taken as an example to analyze the changes of electrical parameters of WPT system under typical faults, and determines that the open load fault has the greatest impact on the system. The WPT system with groove-shaped magnetic shield structure is selected as the research object. Establish a mathematical model for calculating the EMF of the WPT system combining the field-path coupling time-step finite element method and the Maxwell stress method, the distribution law of local EMF of magnetic shielding structure when the load is open is analyzed and calculated. At the same time, an experimental platform is built to verify the effectiveness of the method. According to the distribution characteristics of EMF, the smoothing scheme based on variable-turn-pitch planar coil is proposed. The new coil structure obtained by the SNOPT algorithm, compared with the equi-turn-pitch planar coil, the overall force on the coupling mechanism of transmitting end under the open circuit fault at the receiving end is reduced by 86.24%. This study provides a theoretical reference for the optimal design of coupling mechanism of WPT system.

Recommended citation: Xian Zhang, Fengxian Wang*, Xuejing Ni, Yanan Ren, Qingxin Yang. Structure Electromagnetic Force Analysis of WPT System Under Fault Conditions. IEEE Access. 8.
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