scholarly journals Misalignment and Range Adaptive Wireless Charging System with Constant Current/Constant Voltage Output Based on Coupling Coefficient Estimation

2021 ◽  
Vol 15 ◽  
pp. 334-348
Author(s):  
Wangqiang Niu ◽  
Jiaojiao Liu ◽  
Zaixing Chen ◽  
Wei Gu
Keyword(s):  
Coupling Coefficient ◽  
Input Voltage ◽  
Constant Current ◽  
Secondary Coil ◽  
Constant Voltage ◽  
Wireless Power ◽  
Charging System ◽  
Coefficient Estimation ◽  
Mechanical Isolation ◽  
Range Variation

Compared with the traditional plug-in charging system, wireless power transfer (WPT) system has the characteristics of electrical and mechanical isolation. A wireless system is proposed suitable for battery charging under misalignment or range variation, and the constant current (CC) and constant voltage (CV) charging are realized by the estimation of coupling coefficient. Firstly, two different operating frequencies based on SS basic compensation structure are designed to realize CC output and CV output respectively. After circuit analysis, CC and CV output cannot be achieved when the position of the secondary coil changes. To solve this issue, when the coil is under misalignment or range variations, the required system parameters are measured, and the coupling coefficient in the charging process is estimated by using the transconductance amplitude equation. Then the corresponding input voltage or working frequency is calculated and fine-tuned. Therefore, the CC and CV charge of the battery can be realized under misalignment or range variation. Finally, experimental results are presented to verify the feasibility and correctness of this method.

scholarly journals Constant-Current and Constant-Voltage Output for Single-Switch WPT System with Composite Shielding Structure

2021 ◽  
Vol 13 (1) ◽  
pp. 13
Author(s):  
Quanlei Zhang ◽  
Chunfang Wang ◽  
Lingyun Yang ◽  
Zhihao Guo
Keyword(s):  
Shielding Effect ◽  
Constant Current ◽  
Maximum Efficiency ◽  
Wireless Charging ◽  
Constant Voltage ◽  
Wireless Power ◽  
Zero Voltage Switching ◽  
Charging System ◽  
The Stability ◽  
Zero Voltage

With the development of wireless power transfer (WPT), the wireless charging has become a research hotspot. This paper proposes a novel single-switch hybrid compensation topology, which can change the compensation network to realize the constant-current (CC) and constant-voltage (CV) output. The zero voltage switching (ZVS) margin can be designed to increase the stability of the system. In addition, the magnetic coupler adopts a composite shielding structure composed of ferrite, nanocrystalline, and aluminium foil. The composite shielding structure has a better shielding effect on magnetic flux leakage, and its weight is lighter. The composite shielding structure is expected to be used in the wireless charging system of electric vehicles (EVs). Finally, an experimental prototype is built to verify the theoretical analysis, and the maximum efficiency can reach 91.4%.

scholarly journals Misalignment-Tolerant Series Hybrid with Active Adjustable Constant Current and Constant Voltage Output Wireless Charging System

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7594
Author(s):  
Zhao-Wei Gong ◽  
Jin-Gang Li ◽  
Xiang-Qian Tong
Keyword(s):  
Constant Current ◽  
Outer Diameter ◽  
Wireless Charging ◽  
Constant Voltage ◽  
Load Variations ◽  
Charging System ◽  
Voltage Output ◽  
Operating Region ◽  
Constant Output ◽  
Output Characteristics

This paper presents a series hybrid wireless charging system with an active adjustable circuitry offering constant current and constant voltage output characteristics. The series hybrid system consists of the inductor–capacitor–capacitor (LCC) and series-series (SS) networks are used for improving charging pad misalignment tolerance. An active switch is employed to provide an adjustable CC and CV output for different battery charging stages. To demonstrate the performance of the proposed method, a 310 W prototype was built. A systematic optimization in the parameter of the proposed topology to achieve relative constant output was analyzed within a certain range of the designed operating region. The experimental results indicate that the output current fluctuation is less than 5% with load variations, and the output voltage fluctuation is less than 5% with load varying from 19 to 70 Ω, as the pick-up pads misaligned within 50% of the pad outer diameter.

scholarly journals Primary Control Method of Wireless Charging System Based on Load Characteristics

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1269 ◽  
Author(s):  
Guodong Chen ◽  
Chao Rao ◽  
Yue Sun ◽  
Zhenxin Chen ◽  
Chunsen Tang ◽  
...  
Keyword(s):  
Lithium Ion Battery ◽  
Control Method ◽  
Lithium Ion ◽  
Input Voltage ◽  
Constant Current ◽  
Primary Control ◽  
Wireless Charging ◽  
Charging System ◽  
Equivalent Load ◽  
Secondary Side

Aiming at the output control issues of a lithium ion battery wireless charging system, a primary side control method based on load characteristic identification is proposed. The primary side impedance is calculated by detecting the effective value of the primary side voltage and current, and the mapping relationship between the equivalent load and the primary side impedance is established based on the AC impedance model. Using this mapping relation, the output of the secondary side can be regulated indirectly by controlling the input voltage of the inverter. Compared with the traditional control methods, the proposed control method not only eliminates the communication requirement between the primary side and secondary side, but also simplifies the hardware circuit design, reduces the complexity of the control circuit and also reduces the volume and cost of the system. In the paper, the impedance characteristics of the lithium ion battery at constant current and constant voltage stage are analyzed. The principle of the primary side control method is expounded and the realization method is given. The feasibility of the proposed control method is verified by simulation and experiment.

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