scholarly journals Design Considerations for Adding Series Inductors to Reduce Electromagnetic Field Interference in an Over-Coupled WPT System

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2791
Author(s):  
Yujun Shin ◽  
Jaehyoung Park ◽  
Haerim Kim ◽  
Seongho Woo ◽  
Bumjin Park ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Input Impedance ◽  
High Efficiency ◽  
Harmonic Component ◽  
Power Transfer ◽  
Wireless Power ◽  
Design Considerations ◽  
Harmonic Currents ◽  
Power Transfer Efficiency ◽  
Harmonic Components

This paper analyzes how over-coupled coils affect odd harmonic current and electromagnetic interference (EMI) in a wireless power transfer (WPT) system, and proposes design considerations for series inductors to solve the EMI problem. When the air gap of the coils of the WPT system decreases below a certain level and the coils are over-coupled, the odd harmonic component of the input impedance of the system decreases and odd harmonic currents increase. The increase in the odd harmonic components current quickly aggravates the EMI issues. To solve the EMI problem of the over-coupled WPT system, additional series inductors were applied to the system, and considerations for designing the series inductors were analyzed. When designing additional series inductors, power transfer efficiency, maximum power transfer, input impedance and odd harmonic components current must be considered. Using simulations and experiments, it was confirmed that the WPT system designed with analyzed considerations maintained relatively high efficiency and reduced EMI issues.

Study on the transmission characteristics of magnetic resonance wireless power transfer system

2017 ◽  
Vol 9 (9) ◽  
pp. 1799-1807
Author(s):  
Xiufang Wang ◽  
Yu Wang ◽  
Yilang Liang ◽  
Guangcheng Fan ◽  
Xinyi Nie ◽  
...  
Keyword(s):  
High Efficiency ◽  
Magnetic Coupling ◽  
Wireless Power Transfer ◽  
Parameter Extraction ◽  
Magnetic Flux Density ◽  
Power Transfer ◽  
Wireless Power ◽  
Element Analysis ◽  
Practical Applications ◽  
Power Transfer Efficiency

Magnetic coupling resonance wireless power transfer technology has attracted worldwide attention in recent years due to its mid-range, non-radiative, and high-efficiency power transfer. However, in regard to its practical applications, there are still some issues that need to be considered and studied with respect to coil design, such as coil structure, and parasitic parameter extraction. This paper investigated the characteristics of magnetic coupling resonance wireless power transfer systems with different coil structures, including circular coils and rectangular coils arranged in parallel. We calculated the magnetic field distributions and mutual inductances by subdividing the receiving coils and computing the magnetic flux density of each subdivision. The proposed analysis was validated by means of the finite element analysis and the experimental results. We investigated the effects of the coil's structure, and topological structures, on the power transfer efficiency. The results demonstrate that using circular coils in parallel is more advantageous than using rectangular coils.

scholarly journals A Study on Precise Positioning for an Electric Vehicle Wireless Power Transfer System Using a Ferrite Antenna

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1289
Author(s):  
Jae Yong Seong ◽  
Sang-Sun Lee
Keyword(s):  
Electromagnetic Interference ◽  
Wireless Power Transfer ◽  
Power Transfer ◽  
Wireless Power ◽  
Component Level ◽  
Precise Positioning ◽  
Charging Infrastructure ◽  
Power Transfer Efficiency ◽  
Positioning Method ◽  
The Relationship

In the last decade, engineers from automotive manufacturers and charging infrastructure suppliers have widely studied the application of wireless power transfer (WPT) technology to electric vehicles. Since this time, engineers from automotive manufacturers have studied precise positioning methods suitable for WPT using methods such as mechanical, communication-based or video-based. However, due to high costs, electromagnetic interference and environmental factors, the experts of the SAE J2954 was focused on the WPT’s precise positioning method by ferrite antennas and low power excitation. In this study, we present how to use the ferrite antennas to find a central alignment point between the primary and secondary units within the alignment tolerance area that requires the minimum power transfer efficiency of the EV WPT system. First, we analyze the ferrite antenna already applied in the automotive and verifies whether it is suitable for the precise positioning of the WPT system for EV. We use modeling and simulation to show that it is necessary to calculate all induced loop voltages in the relationship between incident magnetic field signal strength and induced loop voltage because of the short distance between the transmitter and receiver of the ferrite antenna in WPT. In addition, we also suggest a sequence to find the fitting location of the ferrite antenna, the number of antennas used and the center alignment point. After the simulation is performed on the suggestions, component-level and vehicle-level tests were conducted to verify the validity of the simulation results. As a result, it is shown that a ferrite antenna is suitable as a method for the secondary device to find the center alignment point of the primary device.

Rollable metamaterial screen for magnetic resonance coupling-based high-efficiency wireless power transfer

2020 ◽  
pp. 1-9
Author(s):  
Woosol Lee ◽  
Yong-Kyu Yoon
Keyword(s):  
Magnetic Resonance ◽  
High Efficiency ◽  
Wireless Power Transfer ◽  
Network Analyzer ◽  
Power Transfer ◽  
Wireless Power ◽  
Magnetic Resonance Coupling ◽  
Power Transfer Efficiency ◽  
Resonance Coupling ◽  
The Magnetic Field

Abstract This paper presents a rollable metamaterial screen for high-efficiency wireless power transfer (WPT) system based on magnetic resonance coupling, which operates at 4.5 MHz. The rollable metamaterial screen with a fully expanded area of 750 mm × 750 mm is located in the middle between transmitter and receiver coils and focuses the magnetic field and, by such a way, significantly improves power transfer efficiency (PTE). The metamaterial screen can be rolled up, e.g. onto the ceiling when it is not used, and thus does not require any designated space for the screen saving space. A WPT system with the rollable metamaterial screen is designed, fabricated, and characterized. Improved PTE is qualitatively and quantitatively verified by light bulb experiments and vector network analyzer measurements. The PTE of the WPT system with the metamaterial screen increases from 36 to 58.52% and 10.24 to 31.36% for the distances between the transmitter and receiver coils 100 and 150 cm, respectively. The effects of lateral and angular misalignments on the PTE of the WPT system are also studied. Obtained results show that the rollable metamaterial screen improves the PTE even at the misaligned condition.

scholarly journals Optimization of Multiresonant Wireless Power Transfer Network Based on Generalized Coupled Matrix

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Qiang Zhao ◽  
Anna Wang
Keyword(s):  
Optimization Algorithm ◽  
High Efficiency ◽  
Impedance Matching ◽  
Magnetic Coupling ◽  
Wireless Power Transfer ◽  
Transfer Efficiency ◽  
Transfer Model ◽  
Power Transfer ◽  
Wireless Power ◽  
Power Transfer Efficiency

Magnetic coupling resonant wireless power transfer network (MCRWPTN) system can realize wireless power transfer for some electrical equipment real-time and high efficiency in a certain spatial scale, which resolves the contradiction between power transfer efficiency and the power transfer distance of the wireless power transfer. A fully coupled resonant energy transfer model for multirelay coils and ports is established. A dynamic adaptive impedance matching control based on fully coupling matrix and particle swarm optimization algorithm based on annealing is developed for the MCRWPTN. Furthermore, as an example, the network which has twenty nodes is analyzed, and the best transmission coefficient which has the highest power transfer efficiency is found using the optimization algorithm, and the coupling constraints are considered simultaneously. Finally, the effectiveness of the proposed method is proved by the simulation results.

scholarly journals Maximizing Transfer Efficiency with an Adaptive Wireless Power Transfer System for Variable Load Applications

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1417
Author(s):  
Jung-Hoon Cho ◽  
Byoung-Hee Lee ◽  
Young-Joon Kim
Keyword(s):  
Loading Condition ◽  
Wireless Power Transfer ◽  
Input Voltage ◽  
Transfer Efficiency ◽  
Maximum Efficiency ◽  
Variable Load ◽  
Power Transfer ◽  
Wireless Power ◽  
Variable Loading ◽  
Power Transfer Efficiency

Electronic devices usually operate in a variable loading condition and the power transfer efficiency of the accompanying wireless power transfer (WPT) method should be optimizable to a variable load. In this paper, a reconfigurable WPT technique is introduced to maximize power transfer efficiency in a weakly coupled, variable load wireless power transfer application. A series-series two-coil wireless power network with resonators at a frequency of 150 kHz is presented and, under a variable loading condition, a shunt capacitor element is added to compensate for a maximum efficiency state. The series capacitance element of the secondary resonator is tuned to form a resonance at 150 kHz for maximum power transfer. All the capacitive elements for the secondary resonators are equipped with reconfigurability. Regardless of the load resistance, this proposed approach is able to achieve maximum efficiency with constant power delivery and the power present at the load is only dependent on the input voltage at a fixed operating frequency. A comprehensive circuit model, calculation and experiment is presented to show that optimized power transfer efficiency can be met. A 50 W WPT demonstration is established to verify the effectiveness of this proposed approach.

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