The importance of electromagnetic compatibility pre-test in the development process of high-power switching power supplies

Figure 1

Figure 2

Figure 3

Figure 4

Figure 1 shows the conducted disturbance value collected at the power input end.

Figure 2 shows the conducted interference value collected on the power supply line after the line reactor is connected in series. It can be seen that the interference value is reduced by 20-30 db in the frequency range of 1M-5M.

Figure 3 shows the conducted disturbance value collected on the power supply line after the EMI filter is connected in series. It can be seen that the curve has basically dropped below the red line in the range of 300K to 10M, and the largest part has dropped by about 40db, which is a very obvious effect.

Figure 4 shows the conducted interference value collected on the power supply line after the EMI and line reactors are connected in series. It can be seen from the figure that the overall indicators are within the limit value and the expected effect has been achieved.

Since high-power switching power supplies are expensive, it is more economical to conduct pre-tests on their EMC before finalization, improve unreasonable designs, optimize designs, suppress electromagnetic interference, and make EMC meet national standards than to find problems after the equipment is manufactured and then make improvements. Otherwise, manufacturers will pay a high price to solve EMC problems. Figure 5 can better illustrate the problem.

EMC pre-test is a crucial means in the design and development of switching power supplies. For manufacturers, it can solve EMC problems in the early stages of development and reduce development costs; for users, EMC compliance is an important indicator to ensure the electromagnetic environment of their equipment and should be given sufficient attention. Therefore, EMC pre-testing must be performed in the development of high-power switching power supplies.

References

[1] Chen Shufeng, Ma Weiyu, Ma Xiaoqing, Electromagnetic Compatibility Experimental Technology, Beijing University of Posts and Telecommunications Press, 2001