A Comprehensive Review on Wireless Capacitive Power Transfer Technology: Fundamentals and Applications

Abstract

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.INDEX TERMS Capacitive power transfer, capacitive coupling, wireless power transfer.MEHMET ZAHID EREL was born in Sakarya, Turkey. He received the B.S. degree in electrical engineering from the Yildiz Technical University, Istanbul, Turkey, in 2013, and the M.S. degree in electronics and communication engineering from the Ankara Yildirim Beyazit University, Ankara, Turkey, in 2016. He is currently pursuing the Ph.D. degree with the department of electrical and electronics engineering,

Wireless Stand‐Alone Trimodal Interactive Display Enabled by Direct Capacitive Coupling

“…Therefore, the voltage developed on the WiSID is V EL + V L , and the voltage on a display layer ( V EL ) between electrodes E 3 and E 4 (Figure 1d) was obtained by V EL = $$\frac{{{Z_{{\rm{EL}}}}}}{{{Z_{{\rm{total}}}}}} \times {V_{{\rm{input}}}}$$ as a function of input voltage and frequency, where the load impedance was varied from 1 kΩ to 50 MΩ at the given distance of 1 mm (Figures S4 and S5, Supporting Information). [ 44–48 ] The input voltage and frequency of the power unit and the distance between the power and WiSID were chosen to be 525 V, 10 kHz, and 1 mm, respectively.…”

“…When the AC field is applied between the electrodes of the AC power unit, the coupling capacitors alternately charge and discharge, causing a part of the input voltage to be applied between the in-plane electrodes of the WiSID and forming the wireless power flow loop, [44][45][46] (Figure S3 and Note S1, Supporting Information). When no stimuli are applied on the stimuli-responsive layer with initially high AC impedance, the majority of the transferred electric power is applied between the two in-plane electrodes of the WiSID, and this in-plane AC field with a 1 mm gap rarely triggers field-induced EL of ZnS:Cu particles and inverse piezoelectric sound of a PVDF-TrFE, which often require on-set fields of ≈1.2 and 1 V µm −1 for AC EL and inverse piezoelectric sound, respectively.…”

“…as a function of input voltage and frequency, where the load impedance was varied from 1 kΩ to 50 MΩ at the given distance of 1 mm (Figures S4 and S5, Supporting Information). [44][45][46][47][48] The input voltage and frequency of the power unit and the distance between the power and WiSID were chosen to be 525 V, 10 kHz, and 1 mm, respectively. The results in Figure 1e show that ≈50 V (V EL ) formed on the ZnS:Cu/PVDF-TrFE composite layer at the lowest load impedance of 1 kΩ.…”

Conformal Transformation Analysis of Capacitive Wireless Charging

“…We can physically interpret the fringing capacitance as a capacitor that is connected in parallel with the capacitor of a uniform charge distribution on the plates, which is given in (1). Thus, we express the total capacitive of the air-gapped coupler as:…”

“…Inductive power transfer (IPT) carries the power between the inductive couplers using magnetic fields. IPT is the most commonly used technique in high-power charging [1], as it provides the convenience of automatic charging through three modes: static, quasi-dynamic, and dynamic [2]. Thus, it has begun to receive attention for electric cars, buses, and trains charging applications [3].…”