Practical design of a passive EMI filter for reduction of EMI generation

Electromagnetic Interference (EMI) usually generated by a power converter can disturb or damage nearby sensitive electrical/electronic devices/equipment. The use of EMI filter inserted in the considered system is a classical technique for EMI reduction. In order to spend less time and have low cost, this paper proposes a user interface for practical EMI filter design. This interface is easy to use and able to rapidly find out the filter component values. The principle of this design is based on calculation from electromagnetic noises measured by spectrum analyzer, then the algorithm tries to find the cut-off frequency of the filter in order to obtain the attenuated noises respecting to an applied Electromagnetic Compatibility (EMC) standard. The performance of this practical EMI filter design is guaranteed by the real EMI emission measurement. Moreover, this user interface can be useful and used for other power converters, switching devices or EMI sources. Finally, it will reduce time consuming and cost when performing EMC testing in the real work.