| Nowadays, switching power electronic devices have become more integrated and usedin very high-frequency situation, which makes electromagnetic interference makes a verybig problem, it can affect the normal operation of electrical equipment. EMI filter effectsmay deteriorate in different source impedance. Therefore, study the influence of the noisesource impedance to EMI filter has very important engineering value.This paper focuses on two issues with a24V DC power source enclosure as anexperimental platform: How to accurately measure the noise source impedance: and adesign method is proposed to consider the impact of the noise source impedance to the EMIfilter.This paper selects the insertion loss of the source impedance as a method to measurethe noise source impedance, which is inserted into the terminal voltage and the resistancecurve before insertion impedance of the load impedance is calculated by measuring thesource impedance. First, this article summarizes the simulation approach when the sourceimpedance of a different nature, the use of insertion loss method to accurately measure thesource impedance of the need to meet the criteria, and then verify the correctness of theconclusions of the simulation method of the experiment, the final conclusions based on thismeasure and calculate the source impedance of the actual interference source.In the stream of measured impedance24V DC regulated on the basis of this paper, thevoltage source EMI filter to optimize the design. Firstly, EMI filters designed byconventional methods, and then use simulation to calculate the EMI filter at the actualsource impedance of50ohm source impedance and insertion loss curve difference, and thedifference is added to the need to provide EMI filter insertion loss curve, are taken intoaccount the impact of the source impedance insertion loss curves, the last under the newEMI filter insertion loss curve design.Through the simulation of the EMI filters before the optimization and the EMI filtersafter the optimization shows the rationality of optimization methods, and validated in theexperimental platform optimized EMI filter can satisfy the filtering effect. |
