Transformers and EMC: Basic Concepts Explained - Safeguarding the EMC of Power Systems ??

In modern power electronics and transformer design, “EMC” is an indicator that must be focused on. This article will provide you with a detailed introduction to the basic concepts of electromagnetic compatibility (EMC), components and test items, so that you can understand how to ensure that the equipment is not interfered with at the same time, does not interfere with the external environment, so as to achieve efficient and stable operation of the system.

1. Basic Concepts of EMC

EMC (Electromagnetic Compatibility, Electromagnetic Compatibility) refers to the equipment in the electromagnetic environment can work properly, but at the same time will not interfere with other equipment. In other words, a good EMC performance of the equipment can both anti-interference (EMS: Electromagnetic Susceptibility) and will not produce interference (EMI: Electromagnetic Interference).

2. The Three Elements of EMC

When solving EMC problems, we usually start with the following three areas:

• Sources of interference: devices or phenomena that generate electromagnetic interference.
• Interference pathway: The way in which the interference is transmitted, including the two main pathways of wire transmission and space radiation.
• Sensitive source: Equipment or part of a system that is susceptible to interference.

3. EMI Test Items

EMI (Electromagnetic Interference) test mainly evaluates the interference of the equipment to the outside world while working, common items include:

1. Radiated Continuous Nuisance (RE)：Tests the compliance of the equipment with the standard for radiated interference to the surrounding space through the enclosure or ports.
2. Conducted Continuous Nuisance (CE)： Measurement of the interference signal transmitted by a device through a power or signal line.
3. Harmonic current: The strength of the harmonic currents injected into the grid by the test equipment, especially in the case of non-linear loads.
4. Voltage flicker: Examine the effect of voltage fluctuations on other equipment or the human body when the equipment is in operation.
5. Nuisance Power: The energy value associated with current and voltage, reflecting the strength of the interference signal generated by the device.

4. EMS test program

EMS (anti-electromagnetic interference): test mainly evaluates the equipment's immunity to external electromagnetic interference, common items include:

Electrostatic Discharge Immunity (ESD): Simulates the electrostatic discharge that occurs when a person comes into contact with equipment.

Conducted Harassment Immunity (CS): Evaluates a device's resistance to RF interference, usually in the range of 150KHz~230MHz.

Radiated Surge Immunity (RS): Measures the immunity of a device to radiated interference in the 80-1000 MHz band.

Electrical Fast Transient (EFT): Simulates the disturbing pulses generated during the switching of grid equipment.

Surge: Evaluates the ability of a device to withstand lightning strikes or other surges.

Voltage Dips and Short Interruptions Immunity (Dips): This is a test of the equipment's resistance to voltage drops and interruptions.

RMS: Tests the immunity of a device to interference in an industrial magnetic field.

5. The importance of EMC in transformer and power supply design

In the power supply and transformer design, not only between the equipment to meet the EMC requirements, the circuit between the modules and even devices also need to strictly control the electromagnetic interference and anti-interference ability. Ensuring good EMC performance is the key to guarantee the stability and reliability of the power supply ststem. When solving EMC problems, we usually start from the source of interference, interference path and sensitive sources at the same time, through shielding, filtering, grounding and other measures to reduce or eliminate interference.

6. Summary and outlook

EMC, or electromagnetic compatibility, is a key indicator that cannot be ignored in power supply and transformer design. Whether evaluating equipment interference through EMI testing or ensuring equipment immunity through EMS testing, understanding and mastering the basic concepts and test methods of EMC is essential to designing efficient and stable power systems.

Meanwhile, as a professional electronic components supplier, LPEMA is committed to providing high quality transformers and inductors that meet strict EMC requirements. We continuously optimize our design and manufacturing process to ensure that our products are stable while providing high performance and low interference. If you have any questions about EMC design or need technical support, please feel free to contact us!

?? WhatsApp Direct: +86 15171571200

?? Email: [email protected]

?? Official Site: www.lpema.com