Electromagnetic compatibility introductory tutorial (6) test project

EMC检测(Electromagnetic compatibility testing)的全称是Electro Magnetic Compatibility,其定义为“The ability of equipment and systems to function properly in their electromagnetic environment without causing unacceptable electromagnetic disturbance to anything in the environment” This definition has two meanings,首先,The equipment should be able to work normally under certain electromagnetic environment, 即该设备应具备一定的电磁抗扰度(EMS);其次,The electromagnetic disturbance generated by the device itself cannot have an excessive impact on other electronic products,即电磁骚扰(EMI).

EMIinspection items

①谐波电流（2～40次谐波）

②闪烁Flicker

③传导骚扰（CE）

④辐射骚扰（RE）

EMSinspection items

①. 静电放电抗扰度（ESD）;

②. 辐射电磁场（80MHz～1000 MHz）抗扰度（RS）;

③. 电快速瞬变/Burst immunity;

④. 浪涌（雷击）抗扰度;

⑤. 注入电流（150kHz～230MHz）抗扰度（CS）;

⑥. Voltage dips and short interruptions immunity

1、Harmonic（谐波测试）

Standard:EN61000-3-2

a) Specifies limits for harmonic currents emitted to the public grid.

b)Specifies limits for the harmonic content of the input current generated by the device under test in a specific environment.

c) Applies to input current less than or equal to16AThe electrical and electronic equipment connected to the public low-voltage network.

Harmonic testing mainly examines the influence of harmonics in the low-voltage power supply network on these frequency-sensitive equipment.

Principles of harmonic experiments：due to the working mode of electronic equipment、Non-linear components and various interference noise and other reasons,As a result, its input current is not a complete positive dazzling wave,It is often rich in high-order harmonic components and causes pollution to the power grid.

 

 

Harmonics in the power system refer to those whose frequencies are integer multiples of the rated frequency of the power supply system

Sinusoidal voltage or sinusoidal current.

The occurrence of harmonic currents in public transmission systems can cause the following problems﹕

1、more power is lost﹐Every harmonic has a reactive power component、Active power section﹐（The active power will heat the wire﹐This results in a larger area for the wire）;

2、The life of electronic components is shortened;

3、Voltage distortion results in reduced motor efficiency

Harmonic voltage is composed of one or more continuous positive dazzling waves superimposed on the power supply voltage .

Harmonics cause grid voltage distortion

A  class limit

 

2. 电压波动和闪烁 Flicker

Standard: EN 61000-3-3

a）Limits on the effect of constant voltage fluctuations and flicker on the public grid.

b） Guidance for specifying limits and methods of evaluating voltage variations produced by the prototype under test under specified conditions.

c）Applies to each phase input current less than or equal to16Aaccess to the public low-voltage network220V到250V,50Hzof electrical and electronic equipment

The purpose of this standard is to ensure that the product does not cause undue flickering effects to the lighting equipment to which it is connected(灯光闪烁).

The table below shows the allowable minute rate of change or change time for each relative voltage change value.It can be understood that the voltage change range is larger,The less rate of change is allowed,In other words, the time required to change is also greater.

限值：

 

3.传导骚扰 CE (0.15-30MHz)

Standard:EN61000-6-4

A) Electronic and electrical measurement and test equipment

B)Electronic and electrical control equipment

C)Electrical and electronic laboratory equipment

Classification of equipment

Class A: (非家用)equipment suitable for use in all establishments other than domestic and those directly connected to a low voltage power supply network which supplies buildings used for domestic purposes.

Class B: (家用)equipment suitable for use in domestic establishments and in establishments directly connected to a low voltage power supply network which supplies buildings used for domestic purposes.

 

 

Conducted disturbance experiment principle：

When the frequency of electronic equipment interference noise is less than 30MHz, Mainly interferes with the audio frequency band,Cables for electronic equipment for these wavelengths of electromagnetic waves,less than the wavelength of a wave(30MHz的波长为10m), Radiation into the air is inefficient,In this way, the noise voltage induced on the cable can be measured,It can measure the degree of electromagnetic noise interference in this frequency band,This type of noise is conducted noise.

 

LISN的作用：

1.在EUTand high-frequency isolation between the power supply,Avoid the ingress of noise from the power supplyEUT,

影响测量结果.

2.Simulates the actual power supply impedance,为EUTProvide the specified impedance between the power supply terminals,to unify the measurement results.

3.Keep the impedance stable within the test frequency band50欧,to implement and measure the receiver/Input to the spectrum analyzer

阻抗匹配.

4.辐射骚扰 RE (30-1000MHz)

Standard:EN61000-6-4

Classification of equipment

Class A: equipment suitable for use in all establishments other than domestic and those directly connected to a low voltage power supply network which supplies buildings used for domestic purposes.非家用

Class B: equipment suitable for use in domestic establishments and in establishments directly connected to a low voltage power supply network which supplies buildings used for domestic purposes. 家用

a）Electronic and electrical measurement and test equipment

b）Electronic and electrical control equipment

c）Electrical and electronic laboratory equipment

 

 

The principle of radiation harassment experiment：

When the total length of the antenna is greater than the signal wavelengthλ的1/20,Will produce effective radiation emission into space,When the length of the antenna is λ/2的整数倍时,The maximum energy radiated.when the noise frequency is greater than 30MHz时,Cables for electronic equipment,开孔、The gaps are easy to meet the above conditions,form radiation emission.

5.静电放电 ESD

Standard: IEC 61000-4-2 Criteria B

The purpose is to test the ability of a single device or system to resist electrostatic discharge interference.

实验原理：ESDThe experiment is to simulate the human body、Electrostatic discharge or human body when objects come into contact with equipment、The discharge of an object to an adjacent object involves the exchange of energy directly,Near fields caused by device damage or discharge(Changes in electric and magnetic fields),造成设备的误动作.

 

Test Setup

 

6、辐射抗扰度 RS

Standard: IEC 61000-4-3 Criteria A

The purpose is to test the ability of a single device or system to resist electric field interference.

Test Waveform

频率范围：80MHz-2.5GHz,

调制方式：80％ AM, 1kHz sin-wave

频率步长：1％

驻留时间: 3s

Test Setup

 

7、快速脉冲群 EFT/Burst

Standard: IEC 61000-4-4 Criteria B

The purpose of the experiment is to investigate the ability of a single device or system to resist fast transient disturbances,These transient disturbances are due to transient actions such as interruption of inductive loads,lead to the appearance of pulse clusters,High pulse repetition rate,上升时间短,The low energy of a single pulse will cause the equipment to malfunction.

Test Setup

 

8.雷击浪涌 Surge

Standard: IEC 61000-4-5 Criteria B

The purpose of the experiment is to investigateEUT抗浪涌干扰的能力,These transient disturbances are due to faulty short circuits of other equipment,Mains power system switching,Interference caused by indirect lightning strikes, etc.

Test Waveform

 

 

 

9.Conducted radio frequency interference CS

Standard: IEC 61000-4-6 Criteria A

The purpose of the experiment is to examine the ability of a single device or system to resist conducted disturbances.

实验原理：It mainly investigates the introduction of the outside world from wires or cables0.15MHz-80MHzImmunity to continuous disturbance voltage.

Test Waveform

频率范围：0.15MHz-80MHz

调制方式：80％ AM, 1kHz sin-wave

频率步长：1％

驻留时间: 3s

 

 

6.Common frequency magnetic field Rated power frequency magnetic field

Standard: IEC 61000-4-8 Criteria A

The purpose of the experiment is to investigateEUTThe ability to resist magnetic field interference.

*For industrial environment requirements

*For magnetically sensitive equipment,such as Hall elements

 

7.Voltage dips and dips Dips

Standard: IEC 61000-4-11 Criteria B & C

The purpose of the experiment is to investigateEUTResistance to voltage dips and sags.

 

 

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