A Study of Loosely Coupled Coils for Wireless Power Transfer

Chen, Chih‐Jung; Chu, Tah‐Hsiung; Lin, Chih-Lung; Jou, Zeui-Chown

doi:10.1109/tcsii.2010.2048403

Cited by 258 publications

(26 citation statements)

References 13 publications

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“…A typical schematic illustration of an on-road charging system is shown in Figure 1, including power supply, inverter, resonators, AC/DC module, and impedance matching network (IMN). It has been demonstrated by a number of studies that the variations of load impedance have a large influence on WPT system performance [23][24][25]. In an on-road charging system including several EVs, the system will be uncontrollable if all of the load impedances change randomly.…”

Section: Fundamental Analysismentioning

confidence: 99%

“…According to the schematic in Figure 1, the equivalent circuit model can be derived and displayed in Figure 2. The Kirchhoff's voltage law (KVL) equation [24] can then be derived:…”

mentioning

confidence: 99%

“…Inserting the derived mutual inductances into Equation (2), the current of different coils can then be expressed by: The Kirchhoff's voltage law (KVL) equation [24] can then be derived:…”

mentioning

confidence: 99%

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Power Control Strategies of On-Road Charging for Electric Vehicles

et al. 2016

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On-road charging systems for electric vehicles (EVs) have shown revolutionary potential in extending driving range and reducing battery capacities. The optimal equivalent load resistances to maximize receiving power of each EV according to different EV amounts are investigated. This paper introduces a typical on-road charging system with a single transmitting coil and multiple receiving coils. The equivalent circuit models according to different numbers of EVs are built. Power control strategies with regard to a varying number of EVs are then presented. Specifically, self-adaptive source voltage based on primary current detection is utilized to charge EVs, while the source can support enough EVs by providing the rated power. Otherwise, the source voltage is regulated to its maximum value and the charging energy of each EV is suggested to be controlled by adjusting the individual driving speed. A remarkable feature of the power control strategies is that the charging power for each EV is stable and can compensate for energy losses efficiently. As for urgent power demand from a particular EV with a low battery capacity, the adjustment of the corresponding load resistance is applied to alter the power distribution. The proposed technique has been verified in an experimental prototype.

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Section: Fundamental Analysismentioning

confidence: 99%

“…According to the schematic in Figure 1, the equivalent circuit model can be derived and displayed in Figure 2. The Kirchhoff's voltage law (KVL) equation [24] can then be derived:…”

mentioning

confidence: 99%

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Power Control Strategies of On-Road Charging for Electric Vehicles

et al. 2016

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“…On the other hand, from (11) and (13) we get (19) and substituting (19) in (14) and operating, we obtain 2 (20)…”

Section: B Linear Shunt Regulatormentioning

confidence: 99%

Occupancy and Belt Detection in Removable Vehicle Seats Via Inductive Power Transmission

Albesa

Gasulla

2015

IEEE Trans. Veh. Technol.

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Abstract-This work proposes the use of inductive links in order to wirelessly power an autonomous sensor in a vehicle application. The selected application is intended for occupancy and belt detection in removable vehicle seats, where wiring the seat detectors from the vehicle chassis is unpractical. The autonomous sensor includes the seat detectors and a wireless transceiver to transfer the data about the state of the detectors. In order to compensate the loose coupling between the coupled coils, resonant tanks were used. To drive the transmitting resonant network, a commercial class D amplifier was used. Working frequency was restricted to 150 kHz. Commercial magnetic-core coils were selected as they provide high coil values and quality factors in a small-size factor, which is a requirement for the intended application. At the receiving network, a rectifier and a voltage regulator were used to provide a DC voltage supply to the autonomous sensor. Three kinds of voltage regulators were compared from the point of view of the power efficiency. Both a theoretical analysis and experimental results are presented for different combinations of coils and working frequencies. Theoretical analysis shows that the operating points for the linear shunt regulator always lead to higher power efficiencies compared to other alternatives such as linear series and switching buck regulators. Experimental tests were carried out using a mechanical setup to fix the coil-to-coil distances. Experimental results agree with the theoretical analysis. Achieved power efficiencies ranged from around 50% to 10% for coil-to-coil distances from one to three times the inner diameter of the coils. Experimental tests also showed that the autonomous sensor was properly powered up to coil-to-coil distances of 2.5 cm, i.e. more than four times the inner diameter of the coils.

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“…3 times the diameter of the coils) was shown in [6]. The analysis is rather based on physical theory and more engineering focused approaches using circuit lumped circuits have appeared since then [7]. The same principle has also been explored for powering: multiple receivers from a single transmitter coil [8], biomedical implants [9], or even chips [10].…”

Section: Introductionmentioning

confidence: 99%

Wireless Power Transmission for Autonomous Sensors in Removable Vehicle Seats

Albesa

Gasulla

Reindl

2011

2011 IEEE Vehicular Technology Conference (VTC Fall)

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Abstract-This work proposes the use of magnetic coupling for powering autonomous sensors in space-constrained applications, such as occupancy and belt detection in removable vehicle seats. The power demand of the autonomous sensor is considered between tens and hundreds of milliwatts. A theoretical analysis first highlights the critical parameters in order to achieve a large powering range and high efficiency. Series-resonant tanks are considered for both the primary and secondary networks. Because the intended application is space-constrained, small coils have to be used. In order to increase their quality factor, commercial ferrite-core coils are used. A class D power amplifier is proposed for the primary network. Experimental results show that a power of tens of milliwatts can be transferred to a 100 Ω load placed at the secondary network up to a distance of 2 cm, near seven times the radius of the coils (3 mm). The addition of a rectifier and a voltage regulator at the secondary network in order to properly power an autonomous sensor (3 V @ 30 mA) limits the powering range to 1 cm. Overall power efficiencies around 45 % and 20 % are achieved respectively at distances of 5 mm and 1 cm.

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A Study of Loosely Coupled Coils for Wireless Power Transfer

Cited by 258 publications

References 13 publications

Power Control Strategies of On-Road Charging for Electric Vehicles

Power Control Strategies of On-Road Charging for Electric Vehicles

Occupancy and Belt Detection in Removable Vehicle Seats Via Inductive Power Transmission

Wireless Power Transmission for Autonomous Sensors in Removable Vehicle Seats

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