scholarly journals Design of class-E ZVS inverter with loosely-coupled transformer at fixed coupling coefficient

2016 ◽  
Author(s):  
Fabio Corti ◽  
Francesco Grasso ◽  
Alberto Reatti ◽  
Agasthya Ayachit ◽  
Dalvir K. Saini ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Loosely Coupled ◽  
Fixed Coupling ◽  
Class E

Optimal Range of Coupling Coefficient of Loosely Coupled Transformer Considering System Resistance

2021 ◽  
Vol 35 (11) ◽  
pp. 1368-1369
Author(s):  
Jiawei Ge ◽  
Hassan Eldeeb ◽  
Kun Liu ◽  
Jinping Kang ◽  
Haisen Zhao ◽  
...  
Keyword(s):  
Output Power ◽  
Coupling Coefficient ◽  
Wireless Power Transfer ◽  
Transfer System ◽  
Power Transfer ◽  
Wireless Power ◽  
Optimal Range ◽  
Loosely Coupled ◽  
System A ◽  
Wireless Power Transfer System

Accurate system resistance may lead to an obvious error between the simulated and the real efficiency of the system. This paper proposes an optimal range of coupling coefficient for ensuring the efficiency and the sufficient output power of the WPT (wireless power transfer) system. A 3-kW prototype WPT system is manufactured and the effectiveness of the optimal range of coupling coefficient is validated.

scholarly journals Impedance Matching Method for 6.78 MHz Class-E2-Based WPT System

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4289
Author(s):  
Yi Zhang ◽  
Yue Feng ◽  
Sheng Liu ◽  
Jiande Wu ◽  
Xiangning He
Keyword(s):  
Coupling Coefficient ◽  
High Efficiency ◽  
Impedance Matching ◽  
Design Procedure ◽  
System Efficiency ◽  
Matching Method ◽  
Load Impedance ◽  
Load Variations ◽  
System Parameters ◽  
Class E

The performance of a conventional Class-E2-based WPT system is sensitive to system parameters such as the coil coupling coefficient and load variation. System efficiency decreases rapidly when the coil coupling coefficient and load deviate from their optimum values. In this paper, an impedance matching method and a design procedure are proposed to maintain high system efficiency over a wider range of coupling coefficient and load variations. The load-pull technique is adopted to identify the high-efficiency load region of a Class-E power amplifier (PA), and a double-L-type impedance matching network (IMN) is proposed to transform the load impedance of a Class-E PA into a high-efficiency working region. Compared to a single L-type IMN, a double-L-type IMN is more flexible and has better tuning performance. A 6.78MHz Class-E2-based WPT system was built to validate the proposed design method. The experimental results show that the proposed double-L-type IMN can significantly attenuate the decline in Class-E PA efficiency when system parameters dynamically change. With a double-L-type IMN, the WPT system could maintain high efficiency (over 55%) under a wider range of coil coupling coefficient and load variations. The peak system efficiency reached 83.2% with 13.7 W output power. The impedance matching method and design procedure in this paper could provide a practical solution for building a high-efficiency WPT system with strong robustness.

scholarly journals Zero Voltage Switching Condition in Class-E Inverter for Capacitive Wireless Power Transfer Applications

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 911
Author(s):  
Fabio Corti ◽  
Alberto Reatti ◽  
Ya-Hui Wu ◽  
Dariusz Czarkowski ◽  
Salvatore Musumeci
Keyword(s):  
Conversion Efficiency ◽  
Coupling Coefficient ◽  
Design Procedure ◽  
Wireless Power Transfer ◽  
Power Transfer ◽  
Wireless Power ◽  
Zero Voltage Switching ◽  
Zero Voltage ◽  
Voltage Switching ◽  
Class E

This paper presents a complete design methodology of a Class-E inverter for capacitive wireless power transfer (CWPT) applications, focusing on the capacitance coupling influence. The CWPT has been investigated in this paper, because most of the literature refers to inductive power transfer (IWPT). However, CWPT in perspective can result in lower cost and higher reliability than IWPT, because it does not need coils and related shields. The Class-E inverter has been selected, because it is a single switch inverter with a grounded MOSFET source terminal, and this leads to low costs and a simple control strategy. The presented design procedure ensures both zero voltage switching (ZVS) and zero derivative switching (ZDS) conditions at an optimum coupling coefficient, thus enabling a high transmission and conversion efficiency. The novelties of the proposed method are that the output power is boosted higher than in previous papers available in the literature, the inverter is operated at a high conversion efficiency, and the equivalent impedance of the capacitive wireless power transfer circuit to operate in resonance is exploited. The power and the efficiency have been increased by operating the inverter at 100 kHz so that turn-off losses, as well as losses in inductor and capacitors, are reduced. The closed-form expressions for all the Class-E inverter voltage and currents waveforms are derived, and this allows for the understanding of the effects of the coupling coefficient variations on ZVS and ZDS conditions. The analytical estimations are validated through several LTSpice simulations and experimental results. The converter circuit, used for the proposed analysis, has been designed and simulated, and a laboratory prototype has been experimentally tested. The experimental prototype can transfer 83.5 W at optimal capacitive coupling with operating at 100 kHz featuring 92.5% of the efficiency, confirming that theoretical and simulation results are in good agreement with the experimental tests.

Research on the Coupling Coefficient of the Wireless Power Transmission System

2014 ◽  
Vol 912-914 ◽  
pp. 1369-1374
Author(s):  
Yi Cong Liu
Keyword(s):  
Coupling Coefficient ◽  
Power Transmission ◽  
Transmission System ◽  
Simulation Software ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
Loosely Coupled ◽  
Power Transmission System ◽  
Lateral Distance ◽  
Electro Magnetic

The simulation model of wireless power transmission system is based on the experimental model contained E-E-sized core. Analyzing the basic electro-magnetic relation of loosely coupled transformer in the WPT system ,and studying the principle of the energy method to calculate the inductances and coupling coefficient. Using the finite element simulation software to analyze the inductances and coupling coefficient of different air gap, transverse lateral distance and longitudinal lateral distance, finding the effect of the coupling coefficient by the above three situations, which provide a reference for improving the coupling coefficient and efficiency of the wireless power transmission system.

scholarly journals A Heterogeneous Inductive Power Transfer System for Electric Vehicles with Spontaneous Constant Current and Constant Voltage Output Features

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1978
Author(s):  
Jing Zhou ◽  
Pengzhi Yao ◽  
Kan Guo ◽  
Pengju Cao ◽  
Yao Zhang ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Characteristic Curve ◽  
Load Resistance ◽  
Transmission Efficiency ◽  
Constant Current ◽  
Transfer System ◽  
Power Transfer ◽  
Constant Voltage ◽  
Loosely Coupled ◽  
Voltage Output

An inductively coupled wireless power transfer system is proposed in this paper, which is designed to comply with the battery’s load characteristics. A loosely coupled transformer with high coupling coefficient is proposed. A heterogeneous compensation topology is proposed which is able to switch between constant current and constant voltage output mode according to the load resistance. The output characteristic curve agrees with the charging curve of the battery in a whole cycle. The proposed topology has a misalignment range of 300 mm where the coupling coefficient is 0.2. A 3 kW experimental platform is established to verify the theoretical analysis, and the experimental results show that the proposed loosely coupled transformer has high coupling coefficient and high power transmission efficiency (95.2% in aligned position) within a large misalignment range, which agrees with the charging scenario of the electric vehicle.

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