Low conducted EMI in NUPF converters

In design of Near Unity Power Factor (NUPF) converter Electro Magnetic Interference (EMI) is a major problem. This paper provides an approach to minimize conducted EMI by incorporating EMI filter for the flyback NUPF converter. The poor designing of NUPF converter causes EMI noise which should be mitigated. Advances in computer aided design software and device models have enabled the simulation of NUPF converter and to obtain accurate waveform. In this paper LTspice simulation software is used to obtain necessary accurate waveform. The design procedure for designing line filter for NUPF converter is presented here. Simulation is carried out with and without EMI filter and significant reduction of EMI after incorporation of filter has been obtained.