Wisdom

Technical column


CASES


图片名称

GB17625.1:2012 /IEC 61000-3-2:2009 Updated Introduction


 

The current standard for harmonic current emission testing is GB17625.1:2012/IEC 61000-3-2:2009. Compared with the previous version of the testing standard, there are mainly the following updates:

1. GB17625.1: 2012/IEC 61000-3-2: 2009 Clause 6: General requirements for
     equipment that has been slightly changed or upgraded, as long as the current emission of the equipment is lower than the corresponding limit in the original complete compliance test 60%, and the THD of the supply current is less than 15%, a simplified test method can be used. The simplified test method includes: confirming that the change of the active input power of the updated equipment is within ±20% of the power of the original product under test, and the THD of the supply current is less than 15%. Products meeting these two requirements are considered to comply with the corresponding limit value requirements. However, in case of doubt, the complete compliance test results conducted in accordance with Chapters 6 and 7 are given priority.
Key point: For modified products whose power change does not exceed ±20% compared with the prototype, if the harmonic content of the previous prototype does not exceed 60% of the limit, and the total harmonic distortion is less than 15%, then the modified Type products can be directly considered to pass without testing.

2. GB17625.1: 2012/IEC 61000-3-2: 2009 Clause 6.2.2:
     In order to avoid the sharp change of the limit value near a certain power value, the manufacturer may specify and Any value within the deviation range of ±10% of the actual measured power value is used to determine the limit value in the original manufacturer's conformity assessment test. The measured and specified values ​​of power as defined in this clause shall be recorded in the test report.
     If the power value measured in accordance with the provisions of this chapter in the emission test (not measured in the original manufacturer's qualification test) is not less than 90% compared with the power value specified by the manufacturer in the test report (see 6.2.3.5) or not greater than 110%, the specified value shall be used to determine the limit. When the measured value is outside the permissible range of the specified value, the measured power value shall be used to determine the limit value.
     Key point: The actual power test value and the nominal power value should be kept within 10%.

3. GB17625.1: 2012/IEC 61000-3-2: 2009 Clause 7.3 b): Limits for Class C equipment b) The
     third harmonic current expressed as a percentage of the fundamental current should not exceed 86%, and the fifth harmonic wave does not exceed 61%; at the same time, when the fundamental power supply voltage zero-crossing point is used as the reference 0º, the input current waveform should reach the current threshold at or before 60º, peak at or before 65º, and cannot drop below the current threshold before 90º. The current threshold is equal to 5% of the highest absolute peak value occurring within the measurement window within which the phase angle measurement is determined within the period including the highest absolute peak value. See Figure 2. .

Key point: The critical current is 5% of the peak current maximum current.

     For the update of this part, DPA 500N (single-phase harmonic flicker analyzer) and DPA 503N (three-phase harmonic flicker analyzer) of Swiss EMTEST can solve this problem well. Screenshot of software test of lamps with discharge greater than 25W. It can be seen intuitively from the figure whether it is satisfied: when the fundamental power supply voltage zero-crossing point is used as the reference 0º, the input current waveform should reach the current threshold at or before 60º, and reach the current threshold at or before 65º. A peak occurs and cannot drop below the current threshold until 90º. The current threshold is equal to 5% of the highest absolute peak value occurring within the measurement window within which the phase angle measurement is determined within the period including the highest absolute peak value.

Screenshot of dpa.control test software

     According to my 10 years of experience in the field of electromagnetic compatibility, only EMTEST's equipment on the market can achieve this function.
     The following is a brief introduction to the test software, dpa.control - Harmonics and Flicker Control and Analysis Software
     dpa.control is a software tool for remote control of harmonic and flicker analysis systems. It can control all functions of DPA 500N or DPA 503N, upload measurement data records and perform classification and analysis of the equipment under test. dpa.control can not only perform data analysis according to the requirements of the latest version of the standard, but also perform data analysis according to the requirements of the old version of the standard. Its failure/pass judgment function can facilitate users to quickly judge the tested equipment; more detailed data can be used for further analysis and evaluation of the tested equipment.

4. Clause C.3 in Appendix C of GB17625.1: 2012/IEC 61000-3-2: 2009: Test conditions for audio amplifiers
     C.3.1 Conditions
     The input signal of the audio amplifier is at zero and the rated source electromotive force (according to IEC 60268-3 When the change of the power supply current drawn by it is less than 15% of the maximum current, the audio amplifier is tested under no input (signal is zero).
     Other audio amplifiers shall be tested under the following conditions:

  • Rated supply voltage;
  • The normal position of user controls, and in particular any controls that affect the frequency correspondingly, should be set to obtain the widest possible flat response characteristic;
  • Input signal and load given in C.3.2.

     C.3.2 Input signal and load
     application downstream test procedure:
     a) Connect a resistor equal to the rated load impedance to the output of each amplifier. Connect an audio analyzer/oscilloscope to a point in the internal wiring that represents the output of the power amplifier and monitor the speaker audio power amplifier output voltage waveform.
Note 1: If a powered speaker has a built-in audio power amplifier, the speaker and associated crossover network are its loads.
     b) Connect to a matching input with a 1 kHz sinusoidal signal (see Note 2). In a multi-channel amplifier, the surround channel amplifier cannot be used as a second set of left and right channel amplifiers. Therefore, set the input signal of the surround channel amplifier to be 3dB lower than the input signal of the left and right channels.
Note 2: For products not used to reproduce 1kHz signals, the geometric center frequency of the reproduced amplifier bandwidth is used for measurement.
     c) Simultaneously adjust the input signal and/or the gain control of the amplifier to obtain left and right channel output signals with 1% total harmonic distortion. If a 1% THD signal cannot be obtained, simultaneously adjust the input signal voltage and/or gain control to achieve the highest achievable power output at each output. Confirm that the output signal of the surround channel amplifier is 3dB lower than the signal output by the left and right channels.
     d) Measure the output voltage of all channels, adjust the input signal voltage and/or gain control again, so that the output voltage is the same as in the above step c) 0.354 (ie 1/√8) times the output voltage at the end.
     e) Products that are connected to external speakers shall be measured in accordance with the requirements of 6.2.
     f) For products that have an internal speaker and do not provide for connection to an external speaker, record the rms output voltage value for the sinusoidal signal at each amplifier output. Use the pink noise signal instead of the sinusoidal signal, and the band limit is given in 6.1 of IEC 60268-1:1985. Verify that the rms value of the pink noise signal appearing at the output of each amplifier is equal to the rms value of the sinusoidal waveform set in step d) above, measured in accordance with 6.2.
      Key point: Audio power amplifier testing is specified in Appendix C.3.

5. Clause C.5.2 in Appendix C of GB17625.1:2012/IEC 61000-3-2:2009: Lamp
     Discharge lamps should be aged for at least 100h at rated voltage. Before a series of measurements, the discharge lamp has been energized for at least 15 min. Certain types of lamps require a stabilization time in excess of 15 minutes. The information given in the relevant IEC lamp performance standard should be observed.
     During burn-in, stabilization and measurements, the lamp shall be installed as in normal use. Self-ballasted lamps should be operated with the lamp head up.
     Key point: The test status and requirements of lamps (discharge lamps or self-rectifying lamps, etc.) are specified.

6. Clause C.8 in Appendix C of GB17625.1:2012/IEC 61000-3-2:2009: Test conditions for washing machines The washing machine
     should be tested in a complete washing program, that is, the loading size is 70 cm × 70 cm , dry weight 140 g/m2 - 175 g/m2 double seam edge prewashed cotton fabric rated load standard wash cycle.
     The temperature of the injected water should be:

  • 65 °C ± 5 °C for washing machines without heating elements and intended to be connected to a hot water supply;
  • 10 °C - 25 °C for other types of washing machines.

     Washing machines with a programmer should use the 60 °C cotton washing program without pre-washing, otherwise, use the normal washing program without pre-washing operation. If the washing machine has a heating element but is not programmed, the water temperature should be heated to 65 °C ± 5 °C before the first wash cycle starts.
     If the washing machine has a heating element and no program control, the water temperature should be heated to 90 °C ± 5 °C before the first wash cycle starts. The temperature can be lower if steady state conditions have been achieved.
     Key point: The testing status and requirements for washing machines have become more specific.

The Best Solution for Harmonic Current Emission Testing

     

Single Phase Harmonic Analyzer DAP 500N    

   

Three-phase harmonic analyzer DAP 503N

     Fully certified harmonic and flicker analyzers
     DPA 500N and DPA 503N are fully certified harmonic and flicker analyzers that meet the latest editions of IEC/EN 61000-3-2, IEC/EN 61000-3-3 and JIS C 61000-3-2 standard requirements.
     It also meets the requirements of IEC / EN 61000-4-7:2002 and Am.1:2008 (Class I equipment) and IEC / EN 61000-4-15:2003.

 

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