The Comparison of EMI and Electrical Performances of High Frequency Transformer Windings for SMPS Applications

This paper presents the comparison of conducted electromagnetic interference (EMI) and electrical performances effect on various high frequency transformer winding techniques. The windings techniques are focused on conventional winding, sandwiched winding and interleaved winding techniques of the flyback converter. Those winding techniques result a variation of parasitic capacitance which can cause common mode emission of any SMPS system. The comparison is done based on the different winding techniques of transformer and verified by the experiment. The results are not only the conducted EMI aspect, but also the electrical performances such as efficiency, voltage stress, thermal effect, length of winding and weight of transformers. The simulated circuit with proposed parasitic parameter using PSpice program provides a good agreement between simulated results and measured results in conducted EMI emission. Finally, it can be concluded that the interleaved winding technique with 1 mm gap adjustment results the best EMI and electrical performance while the time consumption and thermal effect are compared.