scholarly journals The Design and Optimization of a Wireless Power Transfer System Allowing Random Access for Multiple Loads

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1017 ◽  
Author(s):  
Linlin Tan ◽  
Ming Zhang ◽  
Songcen Wang ◽  
Shulei Pan ◽  
Zhenxing Zhang ◽  
...  
Keyword(s):  
Random Access ◽  
Wireless Power Transfer ◽  
Power Transfer ◽  
Wireless Power ◽  
Design And Optimization ◽  
Highly Sensitive ◽  
In Series ◽  
Overall Efficiency ◽  
Optimizing Control ◽  
The Stability

As is common in multi-load wireless power transfer (WPT) systems based on series–series compensation topology, the power received by loads and the efficiency of the process are highly sensitive to changes in the number of loads. To guarantee that the power supplied to a load remains stable when other loads access or leave the system, we propose an improved multi-load system for WPT. The new system uses an LCC/S topology (based on inductor–capacitor–inductor or LCL topology) to keep the power received by the loads stable. By comparing two scenarios (ideal and real models based on LCC/S topology), we aim to eliminate cross-coupling between receiving coils by connecting compensating capacitors in series on the receiving side. In this way, the stability of the power received by loads is further improved. Moreover, a method of optimizing control over the efficiency is proposed based on the effect on the overall efficiency of impedance and number of loads. This allows us to optimize the overall efficiency of the system. Finally, a system to verify our theoretical analysis is established and used to show the validity and effectiveness of the proposed system.

scholarly journals Enhancing the Stability of Medium Range and Misalignment Wireless Power Transfer System by Negative Magnetic Metamaterials

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5695
Author(s):  
Songcen Wang ◽  
Cheng Jiang ◽  
Xiong Tao ◽  
Feng Chen ◽  
Cancan Rong ◽  
...  
Keyword(s):  
Sharp Decrease ◽  
Wireless Power Transfer ◽  
Transfer Efficiency ◽  
Power Transfer ◽  
Lateral Migration ◽  
Wireless Power ◽  
Angle Variation ◽  
Electromagnetic Simulations ◽  
The Stability ◽  
Electromagnetic Metamaterials

The misalignment of the resonant coils in wireless power transfer (WPT) systems causes a sharp decrease in transfer efficiency. This paper presents a method which improves the misalignment tolerance of WPT systems. Based on electromagnetic simulations, the structural unit parameters of the electromagnetic material were extracted, and an experimental prototype of a four-coil WPT system was built. The influence of electromagnetic metamaterials on the WPT system under the conditions of lateral misalignment and angular offset was investigated. Experiments showed that the transfer efficiency of the system could be maintained above 45% when the transfer distance of the WPT system with electromagnetic metamaterials was 1 m and the resonant coils were shifted laterally within one coil diameter. Furthermore, the system transfer efficiency could be stabilized by more than 40% within an angle variation range of 70 degrees. Under the same conditions, the transfer efficiency of a system without electromagnetic metamaterials was as low as 30% when lateral migration occurred, and less than 25% when the angle changed. This comparison shows that the stability of the WPT system loaded with electromagnetic metamaterials was significantly enhanced.

scholarly journals Detecting Load Resistance and Mutual Inductance in Series-Parallel Compensated Wireless Power Transfer System Based on Input-Side Measurement

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Longzhao Sun ◽  
Mingui Sun ◽  
Dianguang Ma ◽  
Houjun Tang
Keyword(s):  
Wireless Power Transfer ◽  
Input Voltage ◽  
Load Resistance ◽  
Mutual Inductance ◽  
Input Current ◽  
Power Transfer ◽  
Wireless Power ◽  
Direct Measurements ◽  
Input Side ◽  
In Series

In wireless power transfer (WPT) system, the variations in load resistance and mutual inductance influence the output voltage and output current, making the system deviate from its desirable operating condition; hence, it is essential to monitor load resistance and mutual inductance. Using input-side measurement to detect load resistance and mutual inductance has great advantages, because it does not need any direct measurements on the receiving side. Therefore, it can remove sensors on the receiving side and eliminate communication system feeding back the load measurements. This paper investigates load resistance and mutual inductance detection method in series-parallel compensated WPT system. By measuring input current and input voltage, the equation for calculating load resistance is deduced; when the operating frequency is lower than or equal to the receiving-side resonant frequency, the rigorous mathematical derivations prove that load resistance can be uniquely determined by using only one measurement of input current and input voltage. Furthermore, the analytical expressions for identifying load resistance and mutual inductance are deduced. Experiments are conducted to verify the proposed method.

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