Lightning surge immunity test method.power adapter price

　　The national standard for the lightning surge immunity test of switching power adapters is GB/T17626.5, and two versions were released in China in 1999 and 2008, which are respectively the same as the international standards IEC61000-4-5:1995 and IEC61000-4-5. :2001 is the same. Since most domestic product standards have not been revised, the two standards GB/T17626.5-1999 and GB/T17626.5-2008 coexist in China.

　　Lightning strikes are an extremely common natural phenomenon. According to statistics, there are more than 40,000 thunderstorm centers around the world, and there are 8 million lightning strikes every day, which means that there are about 100 lightning strikes every second on the earth. Therefore, the lightning surge resistance test of the switching power supply adapter can establish a common basis for evaluating the switching power supply when it is subjected to high-energy pulse interference.

　　The standard mainly simulates indirect lightning strikes (switching power supplies usually cannot withstand direct lightning strikes), such as: ① the lightning strikes the outdoor power grid lines, and a large amount of current flows into the external lines or grounding resistance, resulting in interference voltage; ② indirect lightning strikes (such as between clouds or clouds (3) Lightning strikes the nearby objects, and the strong electromagnetic field established around them induces voltage on the external lines; 4) The lightning strikes the nearby ground, and the ground current passes through Interference introduced when a common ground system is used.

　　In addition to simulating lightning strikes in nature, the power adapter's surge immunity test standard also mentions the interference introduced by the switching action in substations and other occasions, such as: ① the interference when the main power system is switched; ② the same power grid, in the The interference caused by the beating of some small switches near the switching power adapter; ③ switching thyristor equipment with resonant lines; ④ various systemic faults, such as short circuits and arcing faults between equipment grounding networks or grounding systems.

　　1. Lightning surge immunity test method:

　　⑴ Layout and configuration according to the actual use and installation conditions of the test product, including some standards that will change the additional resistance that reflects the internal resistance of the waveform generator signal source.

　　⑵According to product requirements to determine the level of test voltage and test location.

　　(3) On each selected test site, the positive and negative interferences should be added at least 5 times each, and the maximum repetition rate of each surge is 1 time/min. Because the protection devices used in most systems have a recovery period between surges, there is a problem with the maximum repetition rate when the equipment is tested for lightning surges.

　　⑷ Whether the injection of the surge wave should be synchronized with the input voltage of the switching power adapter. If there is no special provision, it is usually required to superimpose the lightning surge signal on the zero-crossing point and the positive and negative peak positions of the voltage waveform of the switching power adapter.

　　⑸ Considering the non-linearity of the voltage-current conversion characteristics of the equipment under test, the test voltage should be gradually increased to the specified value of the product standard to avoid possible artifacts in the test (at high test voltages, because there may be some A weak device breaks down, bypassing the test voltage, so that the test can pass. However, when the test voltage is low, since the weak device is not broken down, the test voltage is applied to the test equipment at full voltage, but the test fails.) .

　　⑹ Lightning surge signal should be added between line-line or line-ground. If the wire-to-ground test is to be carried out, and there is no special provision, the test voltage shall be applied between each wire and the ground in turn. But it should be noted that when doing the line-to-ground test, sometimes the standard requires the interference to be superimposed on two or more lines to the ground at the same time. At this time, the duration of the pulse is allowed to be reduced.

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