CENTURY WIDOM

Wisdom

图片名称

CN

图片名称

English

图片名称

Search

Technical column

CASES

图片名称

Civil EMS Transient Immunity Period Verification Guide

Release time:

2023-05-24 15:23

Source:

For electromagnetic compatibility testing, the first task is to ensure the accuracy of the experiment. How to ensure the accuracy of the experiment, according to the requirements of GB/T 27025 laboratory system, firstly, all equipment/systems need to be calibrated regularly, and secondly, during the two calibrations, the performance of the equipment/system needs to be checked.

Calibration: A set of operations under specified conditions, the first step is to determine the relationship between the measurement provided by the measurement standard and the corresponding display value, and the second step is to use this information to determine the relationship between the measurement results obtained by the display value, where the measurement standard provides the measurement value and the corresponding display value have measurement uncertainty.

Period verification: the operation of testing equipment, facilities and systems to verify whether their main measurement characteristics or functions can continuously meet the method requirements or specified requirements according to the prescribed procedures between two adjacent calibrations or during use.

1 Civil EMS Transient Immunity recommend Period Verification Method

Verification method of 1.1 electrostatic discharge immunity test system

1.1.1 Test Connection

Figure 1 Schematic diagram of ESD voltage amplitude verification connection

Figure 2 Schematic diagram of ESD current waveform connection

1.1.2 Verification

1.1.2.1 Bleeder resistance verification

Use a digital multimeter to measure the two 470kΩ bleeder resistors connected to the horizontal coupling plate and the vertical coupling plate respectively, and the two 470kΩ resistors can be checked together. When two 470kΩ resistors are checked together, the measuring point should be selected on the metal plate near the bonding point between the discharge resistor cable and the metal plate.

Carbon fiber brushes with bleeder resistors are also subject to bleeder resistance verification.

1.1.2.2 Electrostatic Discharge Simulator Output Voltage Verification

Electrostatic Discharge Simulator works in air discharge mode. Connect the discharge electrode of the electrostatic discharge simulator to the input of the high voltage meter. Measure the open circuit output voltage at different set voltages.

1.1.2.3 Electrostatic discharge simulator contact discharge current waveform verification

See B .4.3 of GB/T17626.2 or A.2.3 of GB/T19951. According to different RC modules, the first peak current, rise time, current at t1 and current at t2 are measured respectively.

1.1.3 Determination

  • Whether the resistance of the discharge resistor is within ± 10% of the value specified in the standard;
  • Results of electrostatic discharge voltage amplitude verification: the voltage Vp amplitude tolerance is ± 5%, within the range specified in IEC 61000-4-2 & GB/T 17626.2 or GB/T 19951.
  • Results of electrostatic discharge current waveform verification parameters: peak current Ip = Vp * 3.75A ± 15%;30ns current amplitude I30 = Vp * 2A ± 30%;60ns current amplitude I60 = Vp * 1A ± 30%; rise time tr = 0.8ns ± 25%, confirm whether it is within the range specified in IEC 61000-4-2 & GB/T17626.2 or GB/T19951.

　　

Fig.3 Example of 4kV current waveform

Fig.4 Measured 4kV current waveform

Verification method for 1.2 electrical fast transient burst immunity test system

1.2.1 Test Connection

Figure 5 Schematic diagram of EFT host verification connection

Fig. 6 Schematic diagram of EFT capacitive coupling clamp verification connection

1.2.2 Verification

Oscilloscope, 50Ω load, 1000Ω load, sensing board (Transducer plate)

1.2.2.1 Pulse group host verification

The output of the host is connected to a 50Ω and 1000Ω coaxial terminal respectively, and the voltage is monitored by an oscilloscope. The oscilloscope's-3dB bandwidth should be at least 400MHz. A composite network is possible for a test load impedance of 1000Ω. See Figure 5 for details of EFT host verification connection diagram.

1.2.2.2 Coupling network verification

The waveform shall be calibrated in the common mode coupling mode, that is, the transient pulse shall be coupled to all lines at the same time. For each coupled line, a 50Ω terminal shall be connected at each output of the coupling/decoupling network to calibrate the waveform separately to the reference ground. CDN output and PVF50 calibration impedance matching adapter for application.

Set the output voltage of the generator to the nominal value of 4kV, and then calibrate. The generator is connected to an input of the coupling/decoupling network. Each output of the coupling/decoupling network (usually connected to the EUT) is in turn terminated to a 50Ω load, with the other outputs open. Record the peak voltage and waveform for each polarity.

1.2.2.3 Capacitive coupling clamp verification

Insert a sense plate (as shown in Figure 6 above) into the coupling clamp and connect to the measurement PVF50 with a low inductance ground connection adapter. The sense plate should be placed in the capacitive coupling clamp and the connection end should be aligned with the edge of the bottom coupling plate. The connection adapter shall be low impedance connected to the reference ground plane for the 50Ω coaxial measurement terminal or attenuator ground.

The generator output voltage is set to 2kV for calibration.

1.2.3 Judgment

Check the parameter results of the electrical fast transient burst immunity test system to confirm whether it is within the range specified in GB/T17626.4.

Fig. 7 Schematic diagram of EFT waveform

8 Peak output voltage and repetition frequency of pulse group

1.2.3.1 Pulse group host verification and determination

  • Peak voltage:

For each set voltage in the above table, measure the output voltage [Vp(50Ω)] when a 50Ω load is connected. The measured voltage value should be Vp(50Ω), and the tolerance is ± 10%;

For the same generator setting (set voltage), measure the voltage [Vp(1000 Ω)] when connected to a 1000Ω load, and the measured voltage value should be Vp(1000 Ω) with a tolerance of 20%;

  • Rise time of all set voltages tr =(5±1.5)ns;
  • Pulse width of all set voltages tw =(50±15)ns or (35~150)ns;
  • The pulse repetition frequency of any set voltage in a pulse group is 5 or 100 kHz;
  • The pulse group duration of any set voltage is 15ms or 0.75ms;
  • Pulse group period of any set voltage 300ms

1.2.3.2 Coupling network verification and determination

  • The rise time of the pulse shall be (5.5±1.5)ns
  • Pulse width shall be (45±15)ns
  • The peak voltage shall be (2±0.2)kV

1.2.3.3 Capacitively coupled clamp verification and determination

  • Rise time (5±1.5)ns;
  • Pulse width (50±15)ns;
  • Peak voltage (1000±200)V

　　

Fig. 9 1kV single pulse waveform measured

1.3 Surge (Impact) Immunity Test System Verification Method

1.3.1 Test Connection

　　

Fig. 10 Schematic Diagram of Voltage Waveform Verification Connection

 

Fig. 11 Schematic Diagram of Current Waveform Verification Connection

1.3.2 Verification:

Oscilloscope, differential probe, current transformer

1.3.2.1 Voltage waveform verification

The output of the surge host is measured in an open circuit state, as shown in Figure 10 for the voltage waveform verification connection diagram.

1.3.2.2 Current waveform verification

The output of the surge host is measured in a short-circuit state, as shown in Figure 11 for the current waveform verification connection diagram.

1.3.3 Judgment:

1.3.3.1 Voltage waveform verification and determination

　　

Fig. 12 Voltage Waveform Requirements of CDN EUT Port

Fig. 13 Open circuit voltage waveform (1.2/50μs)

Fig. 14 Measured diagram of 2kV voltage waveform

1.3.3.2 Current waveform verification and determination

　　

Figure 15 Current Waveform Requirements for CDN's EUT Port

Fig. 16 Short-circuit current waveform (8/20 μs)

Fig. 17 1kV Current Waveform (L-N) Measured

Verification method of 1.4 power frequency magnetic field immunity test system

1.4.1 Test Connection

　　

Fig. 18 Schematic Diagram of Current Amplitude Verification Connection

Fig. 19 Schematic Diagram of Magnetic Field Amplitude Verification Connection

1.4.2 Verification:

Current probe, oscilloscope, magnetic field measuring instrument

1.4.2.1 Current amplitude verification

Test the connection as shown in Figure 18 above, and measure the induced current of the coil;

1.4.2.2 Field strength amplitude verification

The magnetic field probe should be placed in the center of the magnetic field coil, as shown in Figure 19 above.

1.4.3 Judgment:

1.4.3.1 Current amplitude verification and determination

Confirm whether the measured output current value is within ± 10% of the nominal value or within the specified value in the laboratory. Confirm whether the total distortion rate of the measured current is less than 8% of the nominal value or within the specified value of the laboratory;

For example, when the coil factor is 0.87 and the field strength is set to 3A/m, the current probe test value should be 3/0.87=3.45A.

1.4.3.2 Verification and determination of field strength amplitude

Confirm whether the measured magnetic field strength is within ± 20% of the nominal value or within the specified value of the laboratory.

1.5 Voltage Dags, Short Interruptions and Voltage Variations Immunity Test System Verification Methods

1.5.1 Test Connection

　　

Fig. 20 Schematic Diagram of Open Circuit Voltage Amplitude Verification Connection

Fig. 21 Schematic Diagram of Switch Characteristic Verification Connection

1.5.2 Verification:

Differential Probe, 100Ω Pure Load, Oscilloscope

1.5.2.1 Voltage amplitude verification

Connect the equipment as Dip-a in the figure, and measure 100%, 80%, 70% and 40% of the working voltage (220V/120V) after falling.

1.5.2.2 Switch characteristic verification

As Dip-b in the figure, connect the equipment and measure the rising and falling time. The phase angle shall be considered in the measurement. 0/90/180/270 shall be verified. At the same time, the voltage shall be verified from 100 → 80%/100%→ 70%/100%→ 40%/100%→ 0%.

1.5.3 Judgment

The error between the measured voltage amplitude and the set value shall be within 5%;

The rise and fall time of the switch is within 1 ~ 5μs.

　　

Fig. 22 Measured waveform of 40% drop

Century Wisdom (Suzhou) Testing Technology Co., Ltd

Business License
全部
  • 全部
  • 产品管理
  • 新闻资讯
  • 介绍内容
  • 企业网点
  • 常见问题
  • 企业视频
  • 企业图册
Search