Maximum Efficiency Point Tracking for Multiple-Transmitter Wireless Power Transfer

Kim, Do-Hyeon; Ahn, Do-Seob

doi:10.1109/tpel.2019.2919293

Cited by 41 publications

(11 citation statements)

References 26 publications

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“…It means that multi-Tx systems can also deliver the maximum output power only in certain area satisfying critical coupling. Recently, the optimal loads for multi-Tx systems to improve the output power and efficiency in the over-coupled state have been studied [32], [33]. In [32], the optimal load that is applicable to multi-Tx system was derived.…”

Section: Introductionmentioning

confidence: 99%

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Capacitance Tuning Method for Maximum Output Power in Multiple-Transmitter Wireless Power Transfer System

Jeon

Seo

2020

IEEE Access

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It is common knowledge that wireless power transfer (WPT) systems with multiple transmitters (Txs) and a single receiver (Rx) have robust efficiency against lateral misalignment. However, the unnecessary coupling among Txs in actual multi-Tx WPT systems causes transmission efficiency degradation, and then additional tuning work is required to adjust some system parameters, such as the phase or frequency of Tx sources. Moreover, the frequency-splitting phenomenon caused by over-coupling between the Txs and Rx still occurs in multi-Tx systems. Thus, output power degradation is inevitable in the over-coupled state. In this paper, we propose an optimal capacitance tuning method that is applicable to multi-Tx WPT systems. A multi-Tx WPT system tuned with the optimal capacitances, which are obtained from the critical coupling condition between Txs and Rx, not only compensates the inner coupling among Txs but also achieves the maximum output power in the over-coupled state. To verify the validity of the proposed method, we implemented two-and three-Tx and single Rx WPT systems and measured the output power of load with respect to the Rx position along the x-and y-axes. As a result, with the proposed method without any changes in the operating frequency or phase, the systems could deliver higher output power than the conventional phase-controlled system. In particular, with the proposed method, the systems maintained the constant maximum transmission efficiency of 80% in the over-coupled state. INDEX TERMS magnetic beamforming, multiple transmitter, maximum output power, optimal tuning, power transfer efficiency, transmission efficiency, wireless power transfer.

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Section: Introductionmentioning

confidence: 99%

“…However, the effect of inner coupling among Txs was not considered in this study. In [33], the MEPT for multi-Tx WPT systems was introduced. The optimal load value based on system energy efficiency was implemented with the duty cycle topology of a DC-DC converter at 100 kHz.…”

Section: Introductionmentioning

confidence: 99%

Capacitance Tuning Method for Maximum Output Power in Multiple-Transmitter Wireless Power Transfer System

Jeon

Seo

2020

IEEE Access

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“…Recently, multi-coil wireless power transfer (WPT) systems using three or more coils have been proposed to achieve a high power transfer efficiency (PTE) at greater distance than in the case of a conventional two-coil WPT system [1][2][3][4][5][6][7][8][9][10][11][12]. The multi-coil WPT systems are categorized into the domino structure and multiple transmitting (or receiving) coils structure.…”

Section: Introductionmentioning

confidence: 99%

“…To achieve a long transmission distance, the structure adjusts the capacitance of each coil or gaps among coils. On the other hand, multiple transmitting (or receiving) coils correspond to the multiple input single output (MISO) or single input multiple output (SIMO) system in the wireless communication field [7][8][9][10][11][12]. The WPT system with multiple transmitting coils usually maximizes the power in the receiving coil through entering power of different magnitude or phase into transmitting coils.…”

Section: Introductionmentioning

confidence: 99%

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

2020

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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.

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“…Besides, research on high-power applications has made some progress. In [22], researchers studied the optimization of the coil; in [23], the magnetic coupling has been improved, through using the method of adding ferrite core materials. However, most of the designs in previous studies have modeled single transmissions, maximum power transmission, or transmission at highest efficiency.…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis for the Magnetically Coupled Resonant Wireless Energy Transmission System

Liu

Zhang²,

et al. 2019

Complexity

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As a new wireless energy transmission technology, magnetically coupled resonant wireless energy transmission system (MCRETS) is not easily affected by obstacles in the transmission process, and the transmission distance is relatively far. However, how to balance the relationship between transmission efficiency and power to achieve optimal performance is still a huge challenge. In addition, few studies have theoretically investigated the factors affecting the wireless energy transmission system to obtain an optimal solution. Here, through unprecedented theoretical analysis, we find the exact parameters of system optimization and verify them by simulation and experiments. First, the optimal topology of MCRETS is obtained through theoretical analysis and comparison of topologies. Second, to improve the transmission performance of MCRETS, its impact factors, including transmission distance, resonant frequency, relay coil, and relative position of launch and receiving coils, are analyzed in detail to get accurate parameters. Furthermore, based on the analysis, we propose an unprecedented concept for balancing optimal efficiency and power, which is named the power product. Finally, the effectiveness of the proposed method is verified through analysis and experimental results. These findings shed light on the relationship between efficiency and power and provide a comprehensive theoretical basis for subsequent research.

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Maximum Efficiency Point Tracking for Multiple-Transmitter Wireless Power Transfer

Cited by 41 publications

References 26 publications

Capacitance Tuning Method for Maximum Output Power in Multiple-Transmitter Wireless Power Transfer System

Capacitance Tuning Method for Maximum Output Power in Multiple-Transmitter Wireless Power Transfer System

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

Performance Analysis for the Magnetically Coupled Resonant Wireless Energy Transmission System

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