High Frequency Magnetic Properties of Co-Based Amorphous Wound Cores Used for Controlling a Switched-Mode Power Supply

The magnetic properties, and especially the core losses at near-saturation, of Co-Fe-Si-B system amorphous wound cores with various squarenesses are reported. Under ac magnetization at 50 kHz, when control current is zero the core loss increased with the HLm, while core losses were lower for samples with higher dc B-H loop squarenesses Br/Bs. When control current is zero, it is thought that for magnetic amplifier cores, core losses must also be understood, and that a high Br/Bs is useful in lowering core losses at or near core saturation.