Bidirectional Inductive Power Transfer (IPT) systems could enhance the flexibility of energy interaction between electric vehicles (EVs) and the grid, as well as other electrical equipment. Achieving zero-voltage switching (ZVS) conditions is a critical factor in improving the efficiency of bidirectional IPT systems. This paper proposed a double-sided LCC compensation parameter design method, particularly suited for Vehicle-to-Grid (V2G) applications, which realizes the constant current (CC) output during charging process and the constant voltage (CV) output during discharge process of the bidirectional IPT system. A detailed analysis of parameter tuning methods is provided, with the aim of achieving CC/CV output and wide ZVS operation during charging and discharging processes. The inverter turn-off current is accurately estimated, considering the impacts of higher harmonics and the reflected reactance of the rectifier, to optimize the system’s compensation parameters. The effectiveness of the proposed method is verified by a 10-kW bidirectional IPT prototype, and the CC/CV feature and wide ZVS range are achieved. The experimental results demonstrate that the peak efficiency reaches 96.6% when transmitting power as a current source during charging, and 96.2% when transmitting power as a voltage source during discharging.

This article presents a wireless high-voltage power supply (WHPS) that leverages MHz wireless power transfer (WPT) technology with the double-sided LCC compensation topology, achieving high-voltage, high-isolation, high-efficiency, and high-power-density performance. The design utilizes magnetic resonant WPT for primary and secondary side isolation and incorporates multiple receiving coils on the secondary side. Rectifying each coil separately generates multiple direct current (dc) voltages, which are connected in series to produce high voltage output. To attain high power density, stacking of receiving coils and integration of compensation inductors are implemented. However, due to the close proximity of these components, strong coupling results in both mutual inductance and parasitic capacitance. A compensation parameter design method is proposed to decouple mutual inductance and ensure resonant and voltage equalization across each stage. The spatial structures of the coils and inductors are also specifically designed to mitigate the impact of parasitic capacitance, enabling the system's resonant frequency to be elevated to MHz levels. Finally, an 800 W/1.875 MHz WHPS prototype was design and fabricated. Experimental results show that the prototype is capable of converting a 150 V input into a 10 kV output, while maintaining a dc–dc efficiency exceeding 90% across a wide range of load conditions, from 6% to 100%. Moreover, the developed prototype demonstrates a power density of 3.66 kW/L (60 W/in ³ ) and an electrical insulation performance surpassing 35 kV ac.

In this letter, we introduce a novel hybrid wireless power transfer (HWPT) coupler that efficiently integrates magnetic and electric field transmission channels within a single structure using a comb-shaped design. For the first time, this design places electric field coupling plates between two magnetic field coils, while ensuring unobstructed magnetic flux passage and minimizing eddy current losses. This approach significantly enhances overall efficiency and power transfer capability. First, the design methodology of the coupler is elaborated, and a comprehensive analysis of its characteristics is provided. In addition, an equivalent model of the HWPT system with double-LC compensation is established, and the system's output power is derived. An experimental prototype with coupler dimensions of 600 mm × 600 mm and a transmission distance of 150 mm was constructed. The system successfully achieved an output power of 2.2 kW with a dc–dc efficiency of 92.6%, verifying the effectiveness of the proposed structure in reducing losses caused by the integration of magnetic and electric fields.

Wireless charging technologies are widely used in electric vehicles (EVs) due to their advantages of convenience and safety. Conventional wireless charging systems often use planar circular or square spiral windings, which tend to produce strong electric fields (E-fields), leading to electromagnetic interference (EMI) and potential health risks. These standard coil configurations, while efficient in energy transfer, often fail to address the critical balance between E-field emission reduction and power transfer effectiveness. This study presents an “Alternating Voltage Phase Coil” (AVPC), an innovative coil design that can address these limitations. The AVPC retains the standard dimensions of traditional square coils (400 mm in length and width, with a 2.5 mm wire diameter and 22 turns), but introduces a novel current flow pattern called Sequential Inversion Winding (SIW). This configuration of the winding significantly reduces E-field emissions by altering the sequence of current through its loops. Rigorous simulations and experimental evaluations have demonstrated the AVPC’s ability to lower E-field emissions by effectively up to 85% while maintaining charging power. Meeting stringent regulatory standards, this advancement in the proposed coil design method provides a way for WPT systems to meet stringent regulatory standards requirements while maintaining transmission capability.

This paper introduces a perfectly symmetrical planar spiral receiving coil (PS-coil) for large-space wireless power transfer (WPT) systems, designed to significantly reduce electric field (E-field) exposure. The coil’s structure utilizes multiple symmetrically wound spiral wires, replacing traditional single-wire coils. This symmetry facilitates distributed and precise capacitor compensation, effectively mitigating the effects of parasitic capacitance and associated E-field exposure. The PS-coil preserves the magnetic field (H-field) distribution while significantly reducing E-field emissions, allowing for greater power reception within the limits set by the International Commission on Non-Ionizing Radiation Protection guidelines (2020). Finite element simulations indicate that at an effective current of 6 A, the PS-coil achieves a local specific absorption rate (SAR) of 0.72 W/kg at a 1 cm distance—80% lower than traditional designs and well below the 2 W/kg guideline. Finally, a prototype model, comparable in size to an iPad, confirms that the calculated inductance is within 2% of the measured values, with a self-resonance frequency 38% higher than that of traditional coils. Tests in a large space, 3 m in diameter and 2.4 m high, demonstrate that the PS-coil can transmit over 200 W with 54.8% efficiency. Additionally, comparisons of traditional coils with the proposed PS-coil under the same conditions indicated an 18.9 dB reduction in E-field exposure.