With the rapid advancement of electric vehicle (EV) technology, improvements in charging efficiency and energy density have made high-voltage systems a critical core of the overall architecture. However, as charging voltage and current levels increase, the safety and electromagnetic compatibility (EMC) of charging systems face more severe challenges. During high-power transmission, the lack of robust high-voltage protection mechanisms and electromagnetic interference (EMI) suppression designs may lead to component damage, communication errors, or even hazards to personnel. Therefore, developing solutions that combine high-voltage protection and EMI suppression capabilities is essential to ensure the stability and safety of EV charging. This article explores mainstream high-voltage protection strategies and EMI suppression technologies, along with innovative solutions from YAGEO tailored for automotive charging applications.
High-quality capacitors ensure EV charger safety and operational efficiency
A key factor in the widespread adoption of electric vehicles is the availability of convenient charging stations, which enhances consumer purchase intent. EV charging systems often involve high-voltage power transmission ranging from hundreds to thousands of volts. To ensure system safety and compliance with EMC standards, high-voltage protection and EMI suppression solutions are essential. High-voltage protection designs aim to prevent equipment damage or personal hazards caused by overvoltage, overcurrent, short circuits, or insulation failures. High-frequency switching power supplies and large current transmissions in charging systems can generate EMI, interfering with vehicle electronics and communication modules.
Charging stations are categorized into three levels based on current type. Level 1 uses AC <2KW and is suitable for residential applications. Level 2 uses AC 3.9–19.2KW and is designed for indoor public spaces. Level 3 employs DC 24–300KW and is intended for public high-voltage charging. Another emerging trend in EV charging is wireless charging, which eliminates the risk of electric shock, reduces power transmission components, and offers greater convenience.
The design architecture of EV chargers primarily includes an EMI filter, power factor correction (PFC), converters (AC-DC, DC-DC), and filters. Additionally, communication modules, central system units, power controllers, microprocessors, and displays can be integrated to form a complete EV charging system. As charging voltage and power levels rise, high-voltage MLCCs play a critical role in the high-power conversion circuits of fast-charging facilities.
In applications such as DC-Link, snubbers, decoupling, resonant circuits (LLC), and resonant wireless power transfer in EV chargers, capacitors are indispensable. They must meet diverse requirements, including capacitance density, temperature coefficient of capacitance (TCC), voltage coefficient of capacitance (VCC), low ESR, low inductance (ESL), high DC voltage (rated voltage), high AC voltage (pulse), high AC current (ripple current), high-temperature operation (≥125°C), and high-frequency operation (>100kHz). Only high-quality capacitors can ensure the safety and operational efficiency of EV chargers.
High-voltage MLCCs enhance protection against voltage surges and transient spike currents
YAGEO offers a series of high-voltage NPO MLCCs with a wide range of sizes, supporting CC commercial high-voltage applications with case sizes from 0805 to 2220, voltage ranges from 500V to 3KV, and capacitance ranges from 0.2pF to 220nF. For AC automotive high-voltage applications, case sizes range from 0805 to 1210, voltage ranges from 500V to 2KV, and capacitance ranges from 10pF to 33nF. Custom specifications are available, with NPO and X7R dielectric materials, providing the most comprehensive high-voltage portfolio.
YAGEO’s high-voltage NPO MLCC product line includes general termination series supporting 630V with case sizes 1206 and 1210, as well as 1kV with case size 1210. These MLCCs feature soft termination, high thermal stability up to 200°C, a production lead time of 90 days, and DC-rated voltage. They deliver high efficiency, thermal stability, and reliability, making them suitable for industrial power supplies, LLC resonant circuits, charging stations, alternative energy, high-power lighting, and server power supplies.
YAGEO’s high-voltage NPO MLCCs offer improved breakdown voltage, enhancing protection against voltage surges and transient spike currents. This provides higher safety margins for high-voltage applications, reduces failure risks, and ensures product longevity. With lower temperature rise and superior thermal management, these MLCCs minimize overheating risks, extend component lifespan, and improve high-load operational efficiency. Their enhanced reliability, with inner electrode continuity increased from 85% to 93%, ensures stable performance and stronger resistance under stress, delivering exceptional reliability in harsh environments.
YAGEO’s safety capacitors are UL/TUV certified, supporting surge protection and high-frequency EMI filtering. They are available in SC (general termination) and ST (soft termination) types, with case sizes including 1808, 2211, and 2220. The X1/Y2 and X2 series feature NPO and X7R dielectric materials, rated for 250 VAC, withstand 1,500 VAC, and endure impulse voltages of 5,000V (X1/Y2) and 2,500V (X2). Capacitance ranges from 100pF to 5.6nF, with a production lead time of 90 days.
Wired ethernet magnetic components meet EV charger communication needs
Pulse, a division of the YAGEO Group, provides a series of Ethernet magnetic components for EV chargers, including discrete LAN transformers, integrated connector modules (ICMs), signal-level common-mode chokes (CMCs), telecom connectors (RJ45/RJ11, USB, fiber optic cages), and BMS magnetic components. These products serve markets such as industrial and energy, transportation, and communications.
For EV charging stations, YAGEO offers CAN common-mode chokes that meet CAN Class I, II, and CAN-FD Class I speed requirements, with inductance ranging from 11µH to 100µH and package sizes of 1812 and 1210. They operate within a temperature range of -40°C to 125°C.
For ICM products, YAGEO launches JXD2 and JXD7-06 series. The JXD2 series feature a 1x1 structure with top-entry openings and supports speeds from 10/100 to 1 Gigabit, voltage/current IC driven, and GY, GY/GY, or GO/Y (customized) LEDs, with no EMI spring and wave/reflow soldering. The JXD7-06 series includes a 1x1 structure with tab up, supports PoE, is halogen-free, and accommodates speeds from 10/100 to 2.5 Gigabit. It also supports voltage/current IC driven, GY, GY/GY, or GO/Y (customized) LEDs, and optional EMI springs, with wave/reflow soldering.
YAGEO’s RJ-45 connectors, designed for EV charging stations, feature a compact footprint to enhance PCB space efficiency. The 1x1 structure supports Ethernet 100/1000 or RS232/485, with bi-color LEDs indicating operational mode. Their robust design operates in temperatures from -40°C to 85°C.
YAGEO’s SMT power line communication component, the BM6154NL, offers wideband frequency response from 3–30MHz, supporting industrial and automotive temperature ranges of -40°C to 125°C. Its turn ratio accommodates various of PLC chipsets, complies with IEC-62368 for 250V mains supply, meets AEC-Q200 for automotive applications, and can be adapted to ISO/IATF16949 and PPAP designs.
Magnetic product lines deliver exceptional EMI suppression performance
YAGEO’s MSA product line includes EMI cores. The B-20 series features non-split type ferrite beads, compact size and suitable used on the pin of parts on PCBA, wide frequency bands, and bare/coated types, suitable for frequencies from 150KHz to 600MHz. The ESD-R/ESD-R-SR/ESD-R-H/ESD-R-B series uses non-split type ferrite cores in various sizes for cables and power lines, available in bare/coated/cased types, covering frequencies from 250KHz to 600MHz.
The ESD-SR/ESD-SR-H/ESD-SR-HL series employs split type ferrite cores in multiple sizes for cables and power lines, suitable for high-frequency applications from 10MHz to 600MHz. The ESD-R-NC23 series utilizes nanocrystalline material, is non-split type, supports wide-frequency applications and ultra-large sizes, and excels in low-frequency performance (150KHz–600MHz). The ESD-SR-M series features split type ferrite cores with high-µ (5H) material, delivering excellent low-frequency performance (150KHz–10MHz) and large dimensions.
YAGEO’s metal composite power inductor - MPX series - uses metal power material for high-current applications, offering superior EMI performance, high-temperature stability, and high magnetic saturation. It supports rated currents of 2–90A, inductance of 0.1–100µH, and DC resistance (RDC) of 0.48–341.2mΩ.
YAGEO’s flexible suppressors are available in sheet or roll type, using thin, flexible material for portable devices. They are nearly limitless in application, quick to install, easily cut into any shape, RoHS-compliant, and halogen-free. Compliant with AEC-Q200 (FF1 and EFF4) and suitable for SHF bands (EFS), they excel in near-field noise suppression, compensating for shielding case limitations. Ideal for tight spaces like PCB circuits, FPCs, chip packages, or inside shielding cases, they cover common frequency bands such as FM radio, digital TV, LTE, GPS, Wi-Fi, Bluetooth, and optical transceivers. The EFF4 (AECQ-200), FF1 (AECQ-200), EFW, EFX6, FX5, and FW5 series are most effective from 10MHz–2GHz; the EFG2, EFG3, FG1, and FG2 series cover 2GHz–5GHz; and the EFS and FS1 series span 5GHz–50GHz.
Conclusion
As the EV market expands rapidly, the safety and stability of charging systems have become critical design priorities. Robust high-voltage protection measures effectively mitigate risks such as overvoltage, overcurrent, and insulation faults, while advanced EMI suppression technologies significantly reduce electromagnetic interference on communication, control systems, and other electronic components. By considering component selection, circuit design, and system integration, developing charging solutions that combine reliability, and EMC is key to enhancing overall EV charging safety. The high-voltage protection and EMI suppression product lines introduced by YAGEO in this article contribute to a more robust and secure charging environment for electric vehicles.