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.

Parameter identification of wireless power transfer with a movable receiver

2017 ◽  
Vol 36 (6) ◽  
pp. 1580-1593 ◽  
Author(s):  
Quandi Wang ◽  
Yingcong Wang ◽  
Jianwei Kang ◽  
Wanlu Li
Keyword(s):  
Load Condition ◽  
Wireless Power Transfer ◽  
Load Resistance ◽  
Power Transfer ◽  
Wireless Power ◽  
Monitoring Method ◽  
Content Type ◽  
Equivalent Impedance ◽  
Input Side ◽  
Parameter Values

Purpose The purpose of this paper is to present a monitoring method for a three-coil wireless power transfer (WPT) system, which consists of a transmitting coil (Tx), a relay coil and a movable receiving coil (Rx). Both an ideal resistance and a rectifier bridge load are taken into account. Design/methodology/approach From the perspective of fundamental component, the equivalent impedance of a rectifier bridge load is well analyzed. On the basis of the circuit model of a three-coil WPT, estimation equations of the variable mutual inductances and load condition are deduced. Multi-frequency input impedance obtained by frequency scans combined with the Newton-Raphson method are used to obtain solutions. Findings Experimental results indicate that the estimated parameter values are close to each other when different sets of source frequencies are applied. When compared with simulation results, these estimated parameters including both mutual inductances and load resistances are found to be accurate. Originality/value Using only the information of input side, the proposed algorithm can estimate the mutual inductances and load resistance regardless of the Rx positions. Estimation is feasible for the system with a rectifier bridge load. The estimated analysis will serve as a key step in load power stabilization for WPT systems.

scholarly journals A Method of Estimating Mutual Inductance and Load Resistance Using Harmonic Components in Wireless Power Transfer System

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2728 ◽  
Author(s):  
Dongsheng Yang ◽  
Sokhui Won ◽  
Jiangwei Tian ◽  
Zixin Cheng ◽  
Jongho Kim
Keyword(s):  
Wireless Communication ◽  
Wireless Power Transfer ◽  
Mathematic Model ◽  
Load Resistance ◽  
Mutual Inductance ◽  
Transfer System ◽  
Power Transfer ◽  
Wireless Power ◽  
Wireless Power Transfer System ◽  
Harmonic Components

In general, for the WPT (Wireless Power Transfer) system, as the mutual inductance and load resistance are calculated according to the measured data of both the transmitter and receiver, the wireless communication modules are needed to share data. A method for estimating mutual inductance and load resistance without wireless communication is proposed, based on the fundamental and third harmonic components. The circuit is decomposed with respect to the frequencies, by which the mathematic model is established. The fundamental and harmonic components of the output voltage and current of a high-frequency inverter are found by FFT (Fast Fourier Transform). The experimental WPT system with a SiC power MOSFET is designed, and the effectiveness of the proposed method is verified by the simulation and experiment results. Additional hardware and frequency scanning operation are not needed because of the use of the harmonic components.

An Approach for Detecting Illegal Load in Wireless Power Transfer System

2014 ◽  
Vol 599-601 ◽  
pp. 798-801 ◽  
Author(s):  
Xiao Lv ◽  
Lei Zhang ◽  
Ding Dong Zou
Keyword(s):  
High Speed ◽  
System Modeling ◽  
Wireless Power Transfer ◽  
Load Resistance ◽  
Input Current ◽  
Power Transfer ◽  
Wireless Power ◽  
Equilibrium Equations ◽  
Sampling System ◽  
Set Up

In wireless power transfer (WPT) system, detection of illegal load especially the metallic illegal load is necessary to protect the system safety due to the high frequency electromagnetic. This paper presents an efficient and easily-realized method based on energy channels for detecting the legitimacy of load in WPT system. The method is designed that the load at a given frequency to carry out on-off modulation and the primary part demodulation to judge the legitimacy of the load according to the energy equilibrium equations. To realize the proposed method, the relation between primary DC(direct current) input current and secondary load resistance have been analyzed. Therefore, the final detection method is set up which is only required sampling the frequency of DC input current to avoid complex system modeling and requirements of high speed sampling system. Finally experiment and simulation have verified the method which is much efficient and easily-realized for detecting the legitimacy of load accurately.

scholarly journals Wireless Power Transfer for Battery Powering System

Electronics ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 178 ◽  
Author(s):  
Tianfeng Wang ◽  
Xin Liu ◽  
Nan Jin ◽  
Houjun Tang ◽  
Xijun Yang ◽  
...  
Keyword(s):  
Wireless Power Transfer ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Design Guidelines ◽  
Optimization Techniques ◽  
Power Transfer ◽  
Wireless Power ◽  
Power Loss Reduction ◽  
In Series ◽  
Lc Tank

The LCL topology (formed by an LC tank with a transmitting coil) is extensively utilized in wireless power transfer (WPT) systems with the features of a constant resonant current and ability to disconnect load abruptly. However, it requires high input voltage, which limits its utilization in battery powering scenarios (12~24 V). A current-fed inverter (CFI) is applied to the LCL-S (a compensation capacitor in series with the receiving coil) WPT systems to boost the input voltage, thereby getting a higher resonant current in the transmitting side (Tx). To facilitate the voltage regulation in the receiving side (Rx), a semi-active bridge (SAB) is introduced into the system, which further boosts the output voltage by a lower frequency switching at different duty ratios. Rigorous mathematical analysis of the proposed system is carried out and design guidelines are subsequently derived. Moreover, a power loss reduction is realized by zero voltage switch (ZVS) of the four switches in the Tx which are deduced and presented. Simulations and experiments are added to verify the proposed system. Consequently, a 93.3% system efficiency (DC-to-DC efficiency) is obtained using the proposed topology. Optimization techniques for a higher efficiency are included in this study.

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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