How to improve the immunity of frequency converter isolation devices

The application of isolation devices in frequency converters is an effective means to improve the system's anti-interference capability, especially in dealing with common-mode interference. Isolation devices include optocouplers, magnetic couplers, isolation amplifiers, isolated power supplies, and isolated communication modules. They cut off electrical connections through physical barriers (optical, magnetic, and capacitive), thereby blocking ground loops and suppressing common-mode voltage and noise conduction.

Applications that improve anti-interference include: analog signal sampling, such as current and voltage detection, using isolation amplifiers or isolated ADCs to prevent high common-mode noise on the power side from affecting the control side; digital signal transmission, such as drive signals, fault feedback, and communication, using optocouplers or magnetic couplers for isolation; and communication interfaces, such as RS485 and CAN, using isolated transceiver modules. Independent isolated power supplies are provided on both sides of the isolation device. Through isolation, noise can be confined to a local area, preventing it from spreading to the entire system. When selecting isolation devices, attention should be paid to their isolation withstand voltage, common-mode transient rejection capability, and data transmission rate.

During PCB layout, the ground planes on both sides of the isolation strip should be clearly separated. While the proper use of isolation devices increases costs, it fundamentally solves many complex immunity problems and improves the reliability of frequency converters in harsh industrial environments. Eintech provides a wide range of isolation products and solutions to support high-immunity design for frequency converters.