A Survey of Wireless Power Transfer and a Critical Comparison of Inductive and Capacitive Coupling for Small Gap Applications

Dai, Jufeng; Ludois, Daniel C.

doi:10.1109/tpel.2015.2415253

Cited by 523 publications

(197 citation statements)

References 79 publications

Supporting

Mentioning

194

Contrasting

Unclassified

Order By: Relevance

“…Therefore, it can be concluded that C-WPT can be more space-efficient than I-WPT. This is in accordance with the results of the comparative study in [13] : for small separation gap applications (d<1mm), C- WPT has the higher power handling per unit volume of coupling structure, whereas I-WPT has the advantage over the C-WPT method for large gaps (d>1mm).…”

Section: Further Discussionsupporting

confidence: 91%

See 1 more Smart Citation

Design Guidelines for a Capacitive Wireless Power Transfer System with Input/Output Matching Transformers

Choi¹

2016

Journal of Electrical Engineering and Technology

View full text Add to dashboard Cite

-A capacitive wireless power transfer (C-WPT) system uses an electric field to transmit power through a physical isolation barrier which forms a pair of ac link capacitors between the metal plates. However, the physical dimension and low dielectric constant of the interface medium severely limit the effective link capacitance to a level comparable to the main switch output capacitance of the transmitting circuit, which thus narrows the soft-switching range in the light load condition. Moreover, by fundamental limit analysis, it can be proved that such a low link capacitance increases operating frequency and capacitor voltage stress in the full load condition. In order to handle these problems, this paper investigates optimal design of double matching transformer networks for C-WPT. Using mathematical analysis with fundamental harmonic approximation, a design guideline is presented to avoid unnecessarily high frequency operation, to suppress the voltage stress on the link capacitors, and to achieve wide ZVS range even with low link capacitance. Simulation and hardware implementation are performed on a 5-W prototype system equipped with a 256-pF link capacitance and a 200-pF switch output capacitance. Results show that the proposed scheme ensures zero-voltage-switching from full load to 10% load, and the switching frequency and the link capacitor voltage stress are kept below 250 kHz and 452 V, respectively, in the full load condition.

show abstract

Section: Further Discussionsupporting

confidence: 91%

“…According to mathematical formula used in [13], the inductive handling power and the volume of the magnetic coupler structure in Fig. 8 (a) can be estimated by…”

Section: Further Discussionmentioning

confidence: 99%

Design Guidelines for a Capacitive Wireless Power Transfer System with Input/Output Matching Transformers

Choi¹

2016

Journal of Electrical Engineering and Technology

View full text Add to dashboard Cite

show abstract

“…As a kind of transmission mode, capacitive power transfer (CPT, or capacitively coupled power transfer, CCPT) technologies [5], [6] are attracting a growing number of researchers due to their advantages such as design flexibility, reduced volume and weight of the coupling structure and metal penetration capability [7], [8] because capacitive plates are utilized as the coupling structure. CPT technologies have been used in rotating devices [9], mobile robots [10], biological implants [11], cell phones [12], and electric vehicles [13], [14].…”

Section: Introductionmentioning

confidence: 99%

An Interference Isolation Method for Wireless Power and Signal Parallel Transmissions on CPT Systems

Zhou¹,

Su²,

Xie³

et al. 2017

Journal of Power Electronics

View full text Add to dashboard Cite

A novel interference isolation method is proposed by using several designed coils in capacitive power transfer systems as isolation impedances. For each designed coil, its stray parameters such as the inter-turn capacitance, coil resistance and capacitance between the coil and the core, etc. are taken into account. An equivalent circuit model of the designed coil is established. According to this equivalent circuit, the impedance characteristic of the coil is calculated. In addition, the maximum impedance point and the corresponding excitation frequency of the coil are obtained. Based on this analysis, six designed coils are adopted to isolate the interference from power delivery. The proposed method is verified through experiments with a power carrier frequency of 1MHz and a data carrier frequency of 8.7MHz. The power and data are transferred parrallelly with a data carrier attenuation lower than -5dB and a power attenuation on the sensing resistor higher than -45dB.

show abstract

“…Recently, CPT has undergone rapid development from several watt loads to kilowatt-scale loads [8], [9]. Despite such power level advancement, however, the physical limitations in gap distance generally limit the application of CPT, particularly for gap distances greater than 1 mm.…”

Section: Introductionmentioning

confidence: 99%

Design of Capacitive Power Transfer Using a Class-E Resonant Inverter

Yusop¹,

Saat²,

Nguang³

et al. 2016

Journal of Power Electronics

View full text Add to dashboard Cite

This paper presents a capacitive power transfer (CPT) system using a Class-E resonant inverter. A Class-E resonant inverter is chosen because of its ability to perform DC-to-AC inversion efficiently while significantly reducing switching losses. The proposed CPT system consists of an efficient Class-E resonant inverter and capacitive coupling formed by two flat rectangular transmitter and receiver plates. To understand CPT behavior, we study the effects of various coupling distances on output power performance. The proposed design is verified through lab experiments with a nominal operating frequency of 1 MHz and 0.25 mm coupling gap. An efficiency of 96.3% is achieved. A simple frequency tracking unit is also proposed to tune the operating frequency in response to changes in the coupling gap. With this resonant frequency tracking unit, the efficiency of the proposed CPT system can be maintained within 96.3%-91% for the coupling gap range of 0.25-2 mm.

show abstract

A Survey of Wireless Power Transfer and a Critical Comparison of Inductive and Capacitive Coupling for Small Gap Applications

Cited by 523 publications

References 79 publications

Design Guidelines for a Capacitive Wireless Power Transfer System with Input/Output Matching Transformers

Design Guidelines for a Capacitive Wireless Power Transfer System with Input/Output Matching Transformers

An Interference Isolation Method for Wireless Power and Signal Parallel Transmissions on CPT Systems

Design of Capacitive Power Transfer Using a Class-E Resonant Inverter

Contact Info

Product

Resources

About