Silicon Carbide (SiC) power devices have emerged as a transformative technology for high-power wireless charging systems, particularly in electric vehicles (EVs) and industrial robotics. Their superior material properties, including wide bandgap, high thermal conductivity, and high breakdown electric field, enable efficient high-frequency operation, which is critical for resonant converter topologies in wireless power transfer (WPT) applications. This article examines the role of SiC in high-power WPT systems, focusing on resonant converter design, efficiency improvements, and electromagnetic interference (EMI) mitigation strategies.

The adoption of SiC MOSFETs and Schottky diodes in wireless charging systems offers significant advantages over traditional silicon-based devices. SiC devices exhibit lower conduction and switching losses, enabling higher efficiency at elevated switching frequencies. In resonant inductive power transfer systems, operating frequencies typically range from 85 kHz to several megahertz, where SiC’s fast switching capability minimizes dead-time losses and improves power density. For example, a 11 kW wireless charging system utilizing SiC MOSFETs has demonstrated efficiency improvements of 3-5% compared to silicon IGBT-based systems at 85 kHz. At higher frequencies, such as 6.78 MHz (ISM band), the efficiency gap widens further due to SiC’s reduced switching losses.

Resonant converter topologies, particularly series-series (SS) and LCC compensation networks, are widely used in high-power WPT systems. SiC devices enable these topologies to operate at higher frequencies with reduced losses, improving power transfer efficiency and reducing the size of passive components. The SS topology is favored for its simplicity and load-independent constant current output, making it suitable for EV charging. When paired with SiC devices, the SS converter achieves zero-voltage switching (ZVS) more reliably across a wide load range, minimizing switching losses. Experimental studies show that a 20 kW SiC-based SS resonant converter can achieve peak efficiencies exceeding 96% at 85 kHz, with efficiency remaining above 94% across a broad load range.

LCC compensation networks are another promising topology for high-power WPT, offering load-independent voltage output and better misalignment tolerance. SiC devices enhance LCC converter performance by enabling higher operating frequencies without excessive losses. A comparative study between silicon and SiC-based LCC converters at 150 kHz revealed that the SiC implementation reduced total losses by 28%, primarily due to lower switching and conduction losses. The improved efficiency allows for higher power densities, reducing the weight and volume of the charging system—a critical factor for automotive and robotic applications.

Despite these advantages, high-frequency operation introduces significant EMI and electromagnetic compatibility (EMC) challenges. The fast switching transitions of SiC devices, while reducing losses, generate high dv/dt and di/dt rates, leading to increased conducted and radiated emissions. Effective EMI mitigation is essential to comply with regulatory standards such as CISPR 11 and SAE J2954. Common-mode noise is a primary concern in WPT systems due to the parasitic capacitance between the charging coils and the ground plane. SiC-based systems exacerbate this issue due to their higher switching speeds, necessitating robust filtering and shielding techniques.

Active and passive filtering methods are employed to address EMI in SiC-based WPT systems. Passive solutions include common-mode chokes, ferrite cores, and shielded cables to attenuate high-frequency noise. The integration of planar magnetics into the resonant tank can also reduce parasitic effects and improve EMI performance. Active techniques, such as spread-spectrum frequency modulation, help disperse EMI energy across a broader frequency range, reducing peak emissions. Experimental results from a 7.7 kW SiC-based WPT system demonstrated that a combination of common-mode chokes and active filtering reduced conducted EMI by 15 dBµV, ensuring compliance with CISPR 11 Class B limits.

Thermal management is another critical consideration for SiC devices in high-power wireless charging. While SiC’s high thermal conductivity allows for better heat dissipation than silicon, the compact form factors required in EV and robotic applications demand advanced cooling solutions. Liquid-cooled heatsinks and direct-bonded copper substrates are commonly used to maintain junction temperatures within safe limits. Thermal simulations of a 50 kW SiC-based wireless charger showed that liquid cooling reduced peak junction temperatures by 20°C compared to forced-air cooling, enhancing reliability and lifespan.

The application of SiC in industrial robotics wireless charging presents unique challenges and opportunities. Robotic systems often require dynamic charging with high positional flexibility, necessitating efficient power transfer across varying coil alignments. SiC-enabled high-frequency operation allows for smaller receiver coils, improving spatial freedom. A case study involving a 10 kW robotic charging system demonstrated that SiC-based resonant converters maintained 90% efficiency even with a 50% lateral misalignment, outperforming silicon-based systems by 8%.

Future developments in SiC technology will further enhance wireless charging systems. The emergence of 1.2 kV and 1.7 kV SiC MOSFETs enables higher voltage operation, reducing current-related losses in high-power applications. Integrated gate driver solutions optimized for SiC devices are also improving switching performance and reducing parasitic inductance. Research into bidirectional SiC-based WPT systems is progressing, enabling vehicle-to-grid (V2G) capabilities without additional power conversion stages.

In summary, SiC power devices are revolutionizing high-power wireless charging for EVs and industrial robots by enabling efficient, high-frequency resonant converter operation. Their superior switching characteristics improve efficiency and power density, while advanced EMI mitigation techniques ensure compliance with regulatory standards. As SiC technology continues to mature, its adoption in wireless charging systems will expand, driving advancements in energy transfer efficiency, thermal performance, and system reliability. The ongoing development of higher voltage devices and integrated solutions will further solidify SiC’s role in the future of high-power WPT.