Novel evaluation method for the volume of transformers with various magnetic cores

Generally, as operating frequency becomes higher, magnetic components get smaller and lighter. However, higher frequency leads to larger core loss and copper loss. Therefore, the appropriate material of the core and operating frequency needs to be determined to realize well-designed magnetic components. So far, a silicon steel sheet has been used in the low frequency range for large-capacity conversion systems, and ferrite has been used in the high frequency range for small-capacity conversion systems. Recently, new magnetic cores with, for example, amorphous and nanocrystalline materials have been developed that have high saturation magnetic flux density and low core loss. However, the appropriate operating frequency for each magnetic core has not been determined quantitatively. In this study, a novel evaluation method for the volume of transformers using various magnetic cores is proposed. As a result, the volume indicator of the nanocrystalline material has the lowest volume in the range of 1.5 - 40 kHz, and it is the best to operate the nanocrystalline material at 5 kHz for both high efficiency and small size when the saturated temperature rise is 40 K.