scholarly journals Unilateral Route Method to Estimate Practical Mutual Inductance for Multi-Coil WPT System

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 377
Author(s):  
Seon-Jae Jeon ◽  
Sang-Hoon Lee ◽  
Dong-Wook Seo
Keyword(s):  
High Frequency ◽  
Power Transmission ◽  
Transmission Efficiency ◽  
Mutual Inductance ◽  
New Method ◽  
Parasitic Element ◽  
Parasitic Effects

Multi-coil WPT systems require mutual inductance information between coils to increase the power transmission efficiency. However, in the high frequency (HF) bands such as 6.78 MHz and 13.56 MHz, the presence of surrounding coils changes the value of the mutual inductance between the two coils due to the parasitic element effect of the coils. These parasitic effects make it harder to estimate the mutual inductance among three or more coils. In contrast to ideal mutual inductance, which has a constant value regardless of frequency and surrounding coils, we define the practical mutual inductance as the mutual inductance varied by parasitic elements. In this paper, a new method is presented to estimate the practical mutual inductance between multiple coils in the HF band. The proposed method simply configures the expression of practical mutual inductance formula because only one of two bilateral dependent voltage sources generated by mutual inductance is considered. For several coils placed along the same axis, the practical mutual inductances between coils were measured with respect to the distance between them to validate the proposed method. The practical mutual inductance obtained from the proposed method was consistent with the simulated and measured values in HF band.

scholarly journals An Improved Estimation Method of Mutual Inductance Angle for a Two-Dimensional Wireless Power Transfer System

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 448
Author(s):  
Sangyong Lee ◽  
Jeonho Lee ◽  
Jongkyum Kwon ◽  
Se-Kyo Chung
Keyword(s):  
Power Transmission ◽  
Estimation Method ◽  
Wireless Power Transfer ◽  
Transmission Efficiency ◽  
Mutual Inductance ◽  
Transfer System ◽  
Two Dimensional ◽  
Power Transfer ◽  
Wireless Power ◽  
Wireless Power Transfer System

The improvement of power transmission efficiency (PTE) is an important issue in the design of a wireless power transfer (WPT) system. The WPT system with multiple transmitting (Tx) or receiving (Rx) coils is a way to improve the PTE. This paper deals with the estimation of the mutual inductance angle for a two-dimensional (2D) WPT system with two Tx coils and one Rx coil. The mutual inductance angle is one of the most important parameters to determine the PTE in the 2D WPT system. The condition for the maximum PTE is investigated and the mutual inductance angle is defined for the 2D WPT system. An improved estimation method of the mutual inductance angle is proposed based on the phase-locked loop (PLL) technique using the voltages and currents of the Tx coils. The simulation and experimental results are provided to validate the effectiveness of the proposed method.

scholarly journals Design of High Distance Diameter Ratio Wireless Transmission System Based On LCC-S Compensation Network

2021 ◽  
Vol 2113 (1) ◽  
pp. 012028
Author(s):  
Aiwei Yang ◽  
Wei Xie ◽  
Tao Liu ◽  
Xiaobin He
Keyword(s):  
Power Supply ◽  
High Frequency ◽  
Power Transmission ◽  
Transmission Efficiency ◽  
Transmission System ◽  
Diameter Ratio ◽  
Wireless Transmission ◽  
Outer Diameter ◽  
Zero Current ◽  
Power Frequency

Abstract A wireless power transmission system based on LCC-S compensation network is designed. The transmission system is composed of power frequency power supply, LCC-S compensation resonant converter and DC/DC converter, and the output power supply for the battery system. Through the design of transmission coil and compensation network parameters, zero current input is realized. A wireless transmission coil with outer diameter of 47cm and spacing of 30cm is designed. A 2kW wireless transmission system prototype is built. Under 311V input, the actual transmission efficiency of high frequency inverter/wireless transmission/high frequency rectifier reaches 88.5%, and the wireless energy transmission with high distance to diameter ratio is realized.

Improving the efficiency of oilfield electric power distribution

2019 ◽  
pp. 79-87
Author(s):  
Yu. F. Yu. F. Romaniuk ◽  
О. V. Solomchak ◽  
М. V. Hlozhyk
Keyword(s):  
Power Distribution ◽  
Reactive Power ◽  
Power Transmission ◽  
Transmission Efficiency ◽  
Active Power ◽  
Oil Field ◽  
Total Power ◽  
Simultaneous Increase ◽  
Active Load ◽  
Step Down

The issues of increasing the efficiency of electricity transmission to consumers with different nature of their load are considered. The dependence of the efficiency of the electric network of the oil field, consisting of a power line and a step-down transformer, on the total load power at various ratios between the active and reactive components of the power is analyzed, and the conditions under which the maximum transmission efficiency can be ensured are determined. It is shown by examples that the power transmission efficiency depends not only on the active load, but also largely on its reactive load. In the presence of a constant reactive load and an increase in active load, the total power increases and the power transmission efficiency decreases. In the low-load mode, the schedule for changing the power transmission efficiency approaches a parabolic form, since the influence of the active load on the amount of active power loss decreases, and their value will mainly depend on reactive load, which remains unchanged. The efficiency reaches its maximum value provided that the active and reactive components of the power are equal. In the case of a different ratio between them, the efficiency decreases. With a simultaneous increase in active and reactive loads and a constant value of the power factor, the power transmission efficiency is significantly reduced due to an increase in losses. With a constant active load and an increase in reactive load, efficiency of power transmission decreases, since with an increase in reactive load, losses of active power increase, while the active power remains unchanged. The second condition, under which the line efficiency will be maximum, is full compensation of reactive power.  Therefore, in order to increase the efficiency of power transmission, it is necessary to compensate for the reactive load, which can reduce the loss of electricity and the cost of its payment and improve the quality of electricity. Other methods are also proposed to increase the efficiency of power transmission by regulating the voltage level in the power center, reducing the equivalent resistance of the line wires, optimizing the loading of the transformers of the step-down substations and ensuring the economic modes of their operation.

Compensating Resonant Frequency via Adjusting Adjustable Coil Automatically

2019 ◽  
Vol 12 (5) ◽  
pp. 432-438
Author(s):  
Jin Xu ◽  
Yuting Zhao
Keyword(s):  
Resonant Frequency ◽  
Power Transmission ◽  
Reference Value ◽  
Transmission Efficiency ◽  
Theoretical Research ◽  
Future Research ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
Resonant Coupling ◽  
Transmission Distance

Background: Detuning is the main problem that affects the efficiency and transmission distance of the resonant coupling Wireless Power Transmission (WPT). The distance of load and the offset of the load position could cause serious detuning. Methods: This paper presents an adjustable coil in which inductance can be adjusted. Then a model of WPT was established that could compensate resonant frequency automatically using the adjustable coil. Next, the relationship between the primary resonant frequency and the transmission efficiency is analyzed from the circuit. The analysis proved that the design of the adjustable coil could improve the transmission efficiency of the WPT system. Finally, a prototype of WPT system was built. Results: The experimental results showed that WPT system with adjustable coil can improve the transmission efficiency which proves the theoretical research. At the same time, it has essential reference value for the future research of WPT. Conclusion: In this paper, aiming at the system detuning caused by some other factors, such as the position shift of the load during the wireless power transmission, an adjustable coil is proposed.

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