Capacitive Power Transfer for Wireless Batteries Charging

IEEE Access, 2021

Capacitive power transfer (CPT) technology is becoming increasingly popular in various application areas. Due to its limitations, such as low frequency, low coupling capacitance, and the high voltage stress on metal plates, the studies on high power CPT applications fell behind previously. Therefore, the wideband gap (WBG) semiconductor devices and the compensation topologies are further adopted to tackle these limitations. The main purpose of the paper is to review CPT applications in terms of performance parameters, advantages, disadvantages, and also challenges. Initially, the basic principles of CPT technology are examined, which cover compensation topologies, coupler structures, transfer distance, power electronic components, and system control methods. Then, CPT applications are evaluated for performance parameters (i.e., power level, operation frequency, system efficiency, transfer distance) along with compensation types, inverter types, and coupler types. The applications are categorized into six main groups according to industrial topics as safety, consumer electronics, transport, electric machines, biomedical, and miscellaneous. Herein, power level changes from µW to kW ranges, the operation frequency varies from 100s of kHz to 10s of MHz ranges as well. The maximum system efficiency is recorded as 97.1 %. The transfer distance varies from µm range to 100s of mm ranges. The full-bridge inverter topology and four-plate coupler structure are noticeable in CPT applications. Finally, advantages, disadvantages, and challenges of CPT applications are evaluated in detail. This review is expected to serve as a reference for researchers who study on CPT systems and their applications.

Energies, 2021

Wireless power transfer allows the transfer of energy from a transmitter to a receiver without electrical connections. Compared to galvanic charging, it displays several advantages, including improved user experience, higher durability and better mobility. As a result, both consumer and industrial markets for wireless charging are growing rapidly. The main market share of wireless power is based on the principle of inductive power transfer, a technology based on coupled coils that transfer energy via varying magnetic fields. However, inductive charging has some disadvantages, such as high cost, heat dissipation, and bulky inductors. A promising alternative is capacitive wireless power transfer that utilizes a varying electric field as medium to transfer energy. Its wireless link consists of conductive plates. The purpose of this paper is to review the state of the art, link the theoretical concepts to practical cases and to indicate where further research is required to take next st...

IEEE Access

The expanding Electric vehicle (EV) market is fueled by the need for more efficient and dependable ways to recharge the battery. By eradicating the necessity for direct physical interaction between vehicles and charge equipment, the Wireless Power Transfer (WPT) methodology eliminates the drawbacks and risks associated with the conventional conductive system. The innovative WPT technique replaces the conductive charging system to keep a similar power rating and efficiency. Numerous strategies have been created to improve the effectiveness and dependability of the WPT model. As a result, this review article thoroughly analyses current major research literatures that describe WPT technologies for EV charging. The papers are classified based on various coupling types along with magnetic couplers and shielding, compensation, misalignment tolerance and control methods in WPT systems. In addition, the possible research gaps and the challenges associated with the existing works of WPT systems are discussed. The reviewed results are analyzed based on performance metrics and implementation tools attained using above classifications and EMF exposure references employed in the WPT system. The comparative effectiveness is presented in the tables, diagrams, as well as interconnections for ease of presentation and conceptual understanding. The core asset of this article lies in the fact that the findings offer a good ''one-stop'' resource including both aspects of the system and with regard to the power stage. This review article also emphasizes the potential and obstacles of inductive wireless EV battery chargers. A developer can find this study will contribute substantially to selecting an optimum design for the enhancement of the WPT system. INDEX TERMS Capacitive power transfer, compensation, control, coupling, electric vehicle charging, inductive resonant power transfer, wireless power transfer. NOMENCLATURE Abbreviations Descriptions AC Alternating Current. ARIB Association of Radio Industries and Businesses. The associate editor coordinating the review of this manuscript and approving it for publication was Luyu Zhao .

IEEE, 2019

The capacitive power transfer (CPT) technology is mainly used in battery charging systems. The capacitive coupler plays a critical role in a CPT system. The capacitive coupler can be classified into two sections, unipolar and bipolar. The bipolar includes row and column couplers. This paper aims to analyse and compare the capacitive couplers. The plates dimension, plates spacing, and misalignment characteristics were analysed for each coupler. These parameters were considered as criteria to evaluate and compare the capacitive couplers in terms of investigation their effects on the coupling capacitance (Cm). All couplers were examined in a CPT system with a dual LCL compensation circuit topology. The voltage stress of the components, power density, electric field emissions, and safety distance were evaluated. The results showed that the most components in a CPT system of a unipolar coupler have the highest voltage stress among other couplers. This indicates that the CPT system with the unipolar coupler requires passive components with high VA ratings, and high insulation requirements are necessary. Likewise, it was found that the highest power density and lowest safety distance among the other couplers were achieved by the unipolar and column couplers, respectively.

ELECTROTEHNICĂ, ELECTRONICĂ, AUTOMATICĂ (EEA), 2018

Wireless power transfer (WPT) technologies have been developing rapidly in recent years. Advances in technology make WPT widely used in many applications. Electric vehicle (EV) contactless charging is an important application of WPT. Broadly, WPT categorized into radiative and non-radiative power transfer. Radiative power transfer is transmitting high power density, which is unsafe for humans when it is been used for EVs charging. So, only nonradiative power transfer technologies have been using to charge the batteries. Non-radiative power transfer includes inductive power transfer (IPT) and capacitive power transfer (CPT). Inductive charging technology is based on IPT. This paper covers a comprehensive review of an inductive charging system for EVs batteries. Operation principles, equivalent circuits modelling and power transfer requirements are presented. Some system design problems are also presented. Several compensation technologies and coil shape designs proposed to enhance inductive charging performance are also described. However, the air-gap between a charger and an EV, and the magnetic coupling between them are an area of concern. The stationary and dynamic charging methodologies have discussed briefly in this research. The most challenges and limitations of contactless EVs charging have been described in terms of: battery capacity, power level, air-gap, mileage, misalignment tolerance, efficiency, and interoperability. However, battery capacity can be enhanced by dynamic charging, the power level can be controlled, while some other limitations can be improved as discussed in this paper.

Engineering for Rural Development, 2018

The paper discusses the capacitive wireless power transfer (WPT) system for small portable device charging. The capacitive WPT can replace a conventional inductive coupling WPT, because it has no electromagnetic interference, but the capacitive WPT has limitation due to too small coupling capacitance. Therefore, to utilize the capacitive WPT system the switching frequency should be as high as possible: therefore, challenges associated with the design of the power converter working in MHz range will be discussed in details. A calculation of passive components, matching the network and capacitor plate design methodology is given in the paper. The design of the prototype of the capacitive WPT will be described in the paper. This paper proposes to use two copper plates to transfer power, the plates are adopted to generate electric fields and transfer power from the primary side to the secondary side. The equations for calculation of capacitance of the plates are given in the paper. An important task is to calculate the resonant network that generates high voltage in the circuit for high power transfer. The high switching of inverter transistors requires high performance transistors with optimized driver circuit. The design of the inverter and driver circuit is discussed and experimental results are shown.

Energies

Along with the technology boom regarding electric vehicles such as lithium-ion batteries, electric motors, and plug-in charging systems, inductive power transfer (IPT) systems have gained more attention from academia and industry in recent years. This article presents a review of the state-of-the-art development of IPT systems, with a focus on low-voltage and high-current electric mobility applications. The fundamental theory, compensation topologies, magnetic coupling structures, power electronic architectures, and control methods are discussed and further considered in terms of several aspects, including efficiency, coil misalignments, and output regulation capability. A 3D finite element software (Ansys Maxwell) is used to validate the magnetic coupler performance. In addition, a 2.5 kW 400/48 V IPT system is proposed to address the challenges of low-voltage and high-current wireless charging systems. In this design, an asymmetrical double-sided LCC compensation topology and a pa...

2016

In the recent developments of simulation speed and power electronics, the field of wireless power transfer has been developed significantly. In the future transport area, electric vehicles are considered as replacement of oil powered internal combustion engine driven vehicles. Electric Vehicles (EV) have been proposed to achieve environmental friendly transportation. Even though the EV usage is currently increasing, a technology breakthrough would be required to overcome battery related drawbacks. To address battery related limitations, the concept of Wireless Power Transfer (WPT) enabled EVs have been proposed in which EV is being charged while it is in motion or stationary. In this project, the technologies for electric vehicle wireless charging are reviewed using the method of inductive coupling. WPT is the transfer of electrical power from the power source to a load without the use of physical connectors. WPT circuitry is placed inside the vehicle which gets activated when the v...

Eng

Wireless power transfer (WPT) for portable electronic applications has been gaining a lot of interest over the past few decades. This study provides a comprehensive review of the recent advancements in WPT technology, along with the challenges faced in its practical implementation. The modeling and design of WPT systems, including the effect of cross-coupling in multiple receivers, have been discussed and the techniques for efficiency improvement have been highlighted. The challenges of coil design, EMI shielding, and foreign object detection have been pointed out and various cutting-edge solutions have been presented. With improvements in wide bandgap technology, there is a push to operate WPT systems at mega-hertz frequencies. The reason for this is twofold: the miniaturization of the system and the ability to achieve a better magnetic link efficiency. However, with higher frequency comes the challenge of operating the power electronic components efficiently by using soft-switchin...

Journal of Physics: Conference Series, 2014

A wireless power transfer (WPT) using inductive coupling for mobile phone charger is studied. The project is offer to study and fabricate WPT using inductive coupling for mobile phone charger that will give more information about distance is effect for WPT performance and WPT is not much influenced by the presence of hands, books and types of plastics. The components used to build wireless power transfer can be divided into 3 parts components, the transceiver for power transmission, the inductive coils in this case as the antenna, receiver and the rectifier which act convert AC to DC. Experiments have been conducted and the wireless power transfer using inductive coupling is suitable to be implemented for mobile phone charger.