EMC/RFI Products

Solution Overview Problems to Be Solved Solutions What is an EMC Filter Functions of EMC Filters Advantages of EMC Filters Application Fields Conclusion Related Products

Overview of EMC Electromagnetic Compatibility

Electromagnetic Compatibility (EMC) refers to the ability of electronic equipment or systems to function properly in their electromagnetic environment without causing intolerable electromagnetic disturbance to anything in that environment.

EMC is divided into Electromagnetic Interference (EMI) and Electromagnetic Susceptibility (EMS).

With the rapid development of electronic technology, increased device integration, and expansion of operating frequencies into higher bands, the electromagnetic environment has become increasingly complex.

EMC issues have emerged as a critical bottleneck restricting the research, development, production, and application of electronic equipment. These issues may not only lead to performance degradation and functional abnormalities but can even cause safety incidents.

Product or Solution Inquiry

EMC (Electromagnetic Compatibility) Issues That Need to Be Solved

EMC issues exist in numerous fields, including new energy vehicles, medical equipment, communication equipment, industrial automation, frequency converters, new energy, energy storage, lighting, and HVAC.

1

Prominent Conducted Interference Problems in High-Frequency Switching Power Supplies

High-frequency switching power supplies are widely used in new energy vehicle charging equipment, energy storage inverters, and industrial power supplies. During switching, significant differential-mode and common-mode noise is generated and propagates to the power grid through power lines, easily leading to excessive conducted emissions and interfering with the operation of other equipment.
2

Insufficient Equipment Immunity in Complex Electromagnetic Environments

In industrial automation, medical equipment, and communication systems, equipment often coexists with strong interference sources such as frequency converters and motor drives. Electromagnetic noise can enter the system through power lines or spatial coupling, affecting the stable operation of control and signal modules.
3

Electromagnetic Coupling Issues in High-Density Electronic Systems

Miniaturization and high integration of equipment result in denser internal power and signal lines, easily generating crosstalk and electromagnetic coupling, leading to increased system noise, decreased signal quality, and affecting equipment stability.
4

Increasingly Stringent EMC Regulations and Certification Requirements

Electronic equipment must meet strict EMC standards, such as conducted emission and immunity tests. If EMC issues are not fully considered during the design phase, multiple rectifications are often required, increasing R&D costs and delaying product time-to-market.

General EMC Problem Solving Strategies and Solutions

Currently, common electromagnetic compatibility (EMC) mitigation methods in the industrial field mainly include the following categories:

Interference Source Control

By optimizing component selection and circuit underlying design, reduce drastic changes in electromagnetic energy at the source, achieving “prevention before problems occur.”

Component Optimization

Using low-noise components and decoupling circuits to reduce transient current fluctuations.

Waveform Shaping

Adjusting the switch drive resistor or adding RC buffers slows down dv/dt to suppress high-frequency oscillations.

Energy Dispersion

Applying spread spectrum technology to modulate the clock, evenly dispersing peak energy at specific frequency points.
Propagation Path Blocking

Setting up physical or electrical barriers along the path of electromagnetic energy transmission, cutting off radiation and conduction coupling paths through shielding and grounding techniques.

Physical Shielding

Using highly conductive or highly permeable materials to encapsulate the chassis and cables, eliminating spatial coupling interference.

Grounding Construction

Distinguishing between low-frequency single-point grounding and high-frequency multi-point grounding, ensuring ground plane continuity to reduce ground impedance.

Impedance Matching

Grounding and optimizing return paths for high-speed signals significantly reduce loop antenna effects.
Sensitive Equipment Protection

By constructing frequency-selective barriers at power and signal ports, the equipment’s immunity is enhanced, ensuring stable operation in complex electromagnetic environments.

Power Supply Purification

Installing filters at the power input front-end of sensitive modules to effectively prevent conducted noise from the power source.

Signal Protection

Adopting differentiated filtering for signals of different rates: use RC low-pass filtering for low-speed signals and common-mode chokes for high-speed signals.

Spatial Isolation

Implement local shielding and physical isolation for sensitive circuits or modules to block near-field coupling interference.

What is an EMC Filter?

An EMC filter is a key electronic component used to suppress electromagnetic interference in electronic equipment.

It mainly consists of passive components such as inductors, capacitors, and resistors, utilizing the response characteristics of these components to signals of different frequencies to achieve frequency selective filtering.

Its core function is to build a frequency-selective barrier along the interference propagation path, effectively suppressing conducted electromagnetic interference (EMI), thereby ensuring that the equipment neither interferes with others nor is interfered with by others.

In high-frequency, complex electromagnetic environments such as new energy, automotive electronics, and industrial automation, EMC filters have become a critical component for products to pass international standard certifications such as CISPR and IEC.

Main Functions of EMC Filters

EMC filters, by bidirectionally suppressing conducted interference and optimizing signal purity, ensure the stable operation of the equipment itself while helping products overcome the compliance thresholds of electromagnetic compatibility regulations.

Suppressing External Emissions from Interference Sources

Connected in series at the power or signal line input, the filter effectively filters out high-frequency noise generated by internal switching power supplies, motor drives, digital circuits, etc., preventing it from being conducted to the power grid through the power line and affecting other equipment. Especially with the widespread use of switching power supplies, it's almost impossible to meet CISPR 32 or CISPR 11 conducted emission limits without filters.
Protecting Sensitive Circuits from External Interference

External grid disturbances such as surges, harmonics, and radio frequency noise can enter equipment through power lines. EMC filters, with their low-pass characteristics, block high-frequency interference, ensuring stable operation of downstream control circuits, sensors, ADCs, and other sensitive modules.
Achieving Clean Signal Transmission

In communication and data acquisition systems, filters reduce signal distortion and noise superposition, improve the signal-to-noise ratio, and ensure data integrity and system reliability.
Meeting Regulatory and Certification Requirements

Many countries have mandatory standards for EMC compliance of electronic products (such as FCC, CE, CCC). Using appropriate EMC filters is essential for products to pass testing and enter the market successfully.

Advantages of EMC Filters

With advantages such as easy installation, efficient noise suppression, and strong environmental adaptability, EMC Filters provide comprehensive solutions for both EMI suppression and EMS protection.

Simple and Convenient to Use

The filter is directly connected in series in the circuit. Multiple wiring methods are available to suit different needs, making installation simple and quick. During the EMC test validation phase, it can be quickly replaced, facilitating testing, saving time and improving efficiency.
Efficient Electromagnetic Interference Suppression

It can simultaneously suppress differential-mode and common-mode noise, providing excellent interference suppression over a wide frequency band and significantly reducing conducted emissions.
Diverse Forms, Strong Selectability

Whether concerning power rating, installation form, or wiring method, choices can be made based on the customer's actual needs. Suitable products can be found for applications ranging from PCBs to complete machinery.

Strong Environmental Adaptability

In most cases, they feature a metal housing as a carrier, with the interior potted using electronic potting compound. This allows them to operate stably in harsh industrial environments with wide temperature ranges, high humidity, and vibration, and they can function in complex electromagnetic environments.
A Versatile Solution for EMC Issues

EMC filters are generally composed of multiple components forming multi-stage filter units. Therefore, they not only play a major role in solving conducted emission and radiation emission issues but also contribute to resolving EMS issues such as radiation and conducted immunity, electrostatic discharge (ESD), and surges.

Typical Application Areas of EMC Filters

Our company has designed and developed multiple series of EMC filters based on the EMC pain points of different industries and application scenarios.

Application	DC Filters			Single-Phase EMC/EMI Filters							3-Phase EMC/EMI Filters											3-Phase Neutral Line Filters
Application	DFT	DFG	DLF	SFD	SFE	SFG	SFH	SFI	SFT	SRF	EDB	EDC	EFG	EFI	EFO	EFS	EFT	EZC	ALF	MDE	MFE	TFF	TFI	TFO	TRF	MDF	MFT
Transmission & Drive Devices						●	●	●	●		●	●	●	●	●	●						●	●	●
Industrial Robots & Automation						●	●	●			●	●	●	●		●	●					●	●
Semiconductor Equipment					●	●	●	●	●					●		●	●					●	●
Energy Storage Equipment	●	●	●			●	●	●	●				●			●	●	●	●				●	●
Electric Vehicle Equipment & Charging Systems	●	●				●	●	●	●			●		●		●	●	●				●	●
Warehousing & Logistics Automation					●	●		●	●			●		●	●	●							●
HVAC Systems						●	●					●	●	●		●		●				●	●
Lighting Systems						●		●
Medical Instruments & Equipment				●	●	●	●							●						●			●	●		●
Energy Systems	●	●	●			●	●	●	●			●	●	●		●		●	●			●	●
Digital & Information Systems	●	●			●		●	●	●
Shielding & Security Facilities										●															●		●
Military Facilities & Equipment							●			●											●				●		●

Conclusion

With the development of electronic equipment towards higher frequencies and higher power densities, electromagnetic interference problems in new energy vehicles, industrial automation, communication, and new energy systems are becoming increasingly prominent.
EMC design has become a crucial aspect of ensuring stable equipment operation and passing relevant certifications.

Among various EMC mitigation technologies, EMC filters are one of the most direct and effective means of suppressing conducted electromagnetic interference.
By properly configuring filters at the power input, high-frequency noise propagation can be effectively reduced and system electromagnetic compatibility (EMC) performance improved.

To meet diverse application needs, our company offers a variety of EMC filter products, widely applicable in industrial, power supply, and new energy equipment, providing reliable assurance for stable system operation and EMC certification.