Analysis and Design of a Wireless Power Transfer System With an Intermediate Coil for High Efficiency

Moon, SangCheol; Kim, Bong-Chul; Cho, Shin-Young; Ahn, Chi‐Hyung; Moon, Gun-Woo

doi:10.1109/tie.2014.2301762

Cited by 211 publications

(63 citation statements)

References 24 publications

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“…C f is the additional compensation capacitor parallel connected between L f and the original SS-WPT system; C is the original compensation capacitor used in the SS-WPT system but the capacitance has been adjusted in the LCC-WPT system. The load resistance will vary from 5 Ω to 200 Ω to provide a wide range of load conditions, and this load resistance range can be found in existing research on WPT systems operating at around 85 kHz resonant frequency; i.e., in [23], the load resistance is 24.24 Ω; in [24], the load resistance is 30.5 Ω; in [25], the load resistance is 177.6 Ω; in [26], three load resistance values are selected as the load, 15 Ω, 50 Ω, and 200 Ω. The coil to coil vertical displacement is set at 150 mm, giving coupling coefficient of 0.27.…”

Section: Comparison Between the Lcc And The Ss-wpt Systemsmentioning

confidence: 99%

A Design Method for Making an LCC Compensation Two-Coil Wireless Power Transfer System More Energy Efficient Than an SS Counterpart

et al. 2017

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Abstract:A new design approach is presented in this paper to show that under certain conditions, in a two-coil wireless power transfer system, the double-sided inductor-capacitor-capacitor (LCC) compensated wireless power transfer (LCC-WPT) system can be more energy efficient than the series-series (SS) compensated wireless power transfer (SS-WPT) system for the same load power, with special attention being paid to the effect that the parasitic coil and capacitor resistances have on the system efficiency. To make a fair comparison between the SS and LCC WPT systems, the direct current (DC) link voltage was adjusted to set equal load power for the two systems whilst using identical transmit and receive coils, coil-to-coil distance and load resistance. The system performance in terms of the system efficiency, the voltage stresses on the components, and the losses in the power devices were analysed for a practical system, comparing the LCC-WPT system and the SS-WPT system with respect to the load resistance. The effect of coil misalignment on the transferred power and efficiency for the two systems was compared. The theoretical proof and the conditions for meeting the objective are derived and practically verified in a two-coil WPT practical prototype, showing good agreement between analysis and experiments.

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Section: Comparison Between the Lcc And The Ss-wpt Systemsmentioning

confidence: 99%

A Design Method for Making an LCC Compensation Two-Coil Wireless Power Transfer System More Energy Efficient Than an SS Counterpart

et al. 2017

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“…According to Equation (1), the actual load resistance RLa is 12.35 Ω. Considering the errors and assumptions in the calculations, when the parasitic resistance is considered in the design and the calculation, the actual load resistance should be slightly larger than the calculated value and the final load resistance used in the experiments is set to be 15 Ω, which is also of a similar order to that used in various other works dealing with WPT systems for battery charging [21,22]. In this work, the DC voltage is 200 V, and the DC current is 20 A.…”

Section: Design Of the 85 Khz 200 Khz And 500 Khz Wpt Coil Systemsmentioning

confidence: 99%

Design Method for the Coil-System and the Soft Switching Technology for High-Frequency and High-Efficiency Wireless Power Transfer Systems

Liu

Wang

et al. 2017

Energies

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Abstract:Increasing the resonant frequency of a wireless power transfer (WPT) system effectively improves the power transfer efficiency between the transmit and the receive coils but significantly limits the power transfer capacity with the same coils. Therefore, this paper proposes a coil design method for a series-series (SS) compensated WPT system which can power up the same load with the same DC input voltage & current but with increased resonant frequency. For WPT systems with higher resonant frequencies, a new method of realizing soft-switching by tuning driving frequency is proposed which does not need to change any hardware in the WPT system and can effectively reduce switching losses generated in the inverter. Eighty-five kHz, 200 kHz and 500 kHz WPT systems are built up to validate the proposed methods. Experimental results show that all these three WPT systems can deliver around 3.3 kW power to the same load (15 Ω) with 200 V input voltage and 20 A input current as expected and achieve more than 85% coil-system efficiency and 79% system overall efficiency. With the soft-switching technique, inverter efficiency can be improved from 81.91% to 98.60% in the 500 kHz WPT system.

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“…To relieve the efficiency fall, one method is increasing the working frequency for a high quality factor of the coils so that the conduction loss caused by the coil resistance is reduced [24][25][26], although it was shown later that this method is not suitable for situations requiring a large amount of delivered power which is inversely proportional to frequency [24]. Besides, the intermediate coil is another way for improving efficiency [27][28][29][30][31][32], which could create large magnetic coupling with the receiver thus only small current is needed in the primary driving circuit [27]. The working mechanism for the relay coil is that it firstly receives the magnetic field from the transmitter coil and then transfers it to the receiver coil, apparently increases the coupling coefficient resulting a higher efficiency [28].…”

Section: Introductionmentioning

confidence: 99%

“…Besides, the intermediate coil is another way for improving efficiency [27][28][29][30][31][32], which could create large magnetic coupling with the receiver thus only small current is needed in the primary driving circuit [27]. The working mechanism for the relay coil is that it firstly receives the magnetic field from the transmitter coil and then transfers it to the receiver coil, apparently increases the coupling coefficient resulting a higher efficiency [28]. The optimal coil geometries for a 3-coil IPT system could be found in [23].…”

Section: Introductionmentioning

confidence: 99%

A Three-Coil Inductively Power Transfer System with Constant Voltage Output

et al. 2018

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For a traditional 2-coil system outputting constant voltage (CV), the transfer efficiency decreases drastically as transfer distance increases. To solve this problem, this essay proposes a 3-coil system which could achieve CV output and Zero Phase Angle (ZPA) conditions with specific parameter values. This 3-coil system could partly relief transfer efficiency fall at a long transfer distance, without any complicated controls. In order to achieve CV and ZPA condition, this essay devises the parameter values based on the decoupling 3-coil model, and a prototype is designed accordingly to verify these characteristics. With 10 cm transfer distance, output voltage deviation is 5.5% as the load varies from 12 Ω to 200 Ω, proving that the output voltage almost keeps constant with load change. Furthermore, with software simulation, a comparison experiment between the proposed 3-coil system and a Series-Inductor-Capacitor-Inductor (S-LCL) compensated 2-coil system is built to verify the efficiency improvement. The transfer distance change leads to the differentiation of voltage gain for both 2-coil and 3-coil systems. So, the input voltage for both systems and the compensated capacitor in receiver loop of the 3-coil system are manipulated for keeping 60 V output voltage on the 12 Ω load. With distance increasing from 10 cm to 20 cm, transfer efficiency varies from 92.61 to 48.9% for the 2-coil system, and from 92.89 to 84.26% for the 3-coil system, effectively proving the efficiency improvement. The experiment and simulation results prove the effectiveness of the proposed method.

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Analysis and Design of a Wireless Power Transfer System With an Intermediate Coil for High Efficiency

Cited by 211 publications

References 24 publications

A Design Method for Making an LCC Compensation Two-Coil Wireless Power Transfer System More Energy Efficient Than an SS Counterpart

A Design Method for Making an LCC Compensation Two-Coil Wireless Power Transfer System More Energy Efficient Than an SS Counterpart

Design Method for the Coil-System and the Soft Switching Technology for High-Frequency and High-Efficiency Wireless Power Transfer Systems

A Three-Coil Inductively Power Transfer System with Constant Voltage Output

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