The Strategic Role of Air-Core Coils in New Energy Vehicles (NEV)

1. Motor Drive Systems

High-Frequency Inductors: Used in DC-AC inverters for motor drives as filter or resonant inductors. They effectively suppress high-frequency switching noise, especially for SiC/GaN devices operating at frequencies above 100kHz.

Current Sensors (Rogowski Coils): Utilized for non-contact current detection in motor phases. These offer high precision without the risks of magnetic saturation.

Requirements: High-temperature resistance (above 150C) and low parasitic capacitance to minimize high-frequency loss.

2. On-Board Chargers (OBC) and DC-DC Converters

LLC Resonant Inductors: Air-core coils are integral to high-frequency resonant circuits (50kHz to 1MHz), significantly boosting charging efficiency.

EMI Filter Inductors: These coils filter out electromagnetic interference during the charging process, requiring broadband characteristics (100kHz to 30MHz).

Requirements: High Quality Factor (Q over 100) and high voltage tolerance (above 600V).

3. Wireless Power Transfer (WPT) Systems

Transmitter and Receiver Coils: Planar air-core coils (typically spiral or DD-shaped) are used for magnetic field coupling to transfer power at frequencies between 85kHz and 150kHz.

Requirements: Ultra-low AC resistance (using Litz wire to reduce skin effect) and high mechanical strength to prevent deformation from road vibrations.

4. Battery Management Systems (BMS)

Current Monitoring: Rogowski coils are employed for total battery pack current detection, eliminating the hysteresis errors found in traditional current transformers (CT).

Requirements: Linearity error under 1% and extreme thermal stability across a range of -40C to 125C.

5. High-Voltage Power Distribution Units (PDU)

Fast-Charging Relay Protection: Air-core coils detect instantaneous high currents (such as short circuits) to trigger protective circuitry.

Requirements: Microsecond-level (us) response time and tolerance to surge currents exceeding 10kA.

6. Automotive Electronics (Infotainment and ADAS)

RF Antennas: Used in GPS and 5G antennas (frequencies above 1GHz) due to their low dielectric loss.

Radar Sensors: In 77GHz millimeter-wave radar, matching inductors require air-core structures to eliminate high-frequency core loss.

7. Auxiliary Systems

Electromagnetic Suspension: Air-core coils serve as driving elements for electromagnetic valves, offering millisecond-level (ms) response.

Thermal Management: Used in proportional solenoid valves to control refrigerant flow.

Future Technical Trends and Challenges

High Frequency: The popularity of SiC/GaN devices is pushing air-core coil designs into the MHz range.

Integration: Move toward planar air-core coils integrated directly into PCBs (embedded spiral inductors).

Lightweighting: Exploring the replacement of copper with aluminum wire, which requires solving complex oxidation and welding challenges.

Summary

The penetration of air-core coils in the NEV sector will continue to rise, particularly as they replace traditional core-based inductors in high-power density and high-frequency scenarios. For mass production, the focus must remain on high-frequency parameter consistency and advanced automated winding processes.

About Guangdong Zongheng Technology Co., Ltd.

With 19 years of dedicated expertise, Guangdong Zongheng Technology focuses on the R&D and intelligent manufacturing of forming winding machines for Air-Core Coils, Alpha Coils, and Voice Coils.

Contact Us:

Phone: +86-139-2581-0131 (Mr. Feng)