Basic Characteristics of Soft Magnetic Materials – Magnetic Loss
Basic Characteristics of Soft Magnetic Materials – Magnetic Loss
Magnetic Core and Transformer
Issues related to magnetic loss caused by dynamic magnetization, including its impacts, composition, causes and reduction approaches, are detailed as follows:
Impacts of Magnetic Loss from Dynamic Magnetization
• Energy Waste: Dynamic magnetization is mainly applied in alternating magnetic fields; although the magnetic loss is not substantial, it leads to energy waste.
• Performance Impact: Magnetic loss causes the material to generate heat, which impairs the performance of both the material and the device.
• Frequency Limitation: It results in frequency dispersion of the material’s permeability, restricting the operating frequency range of the material.
Composition of Magnetic Loss from Dynamic Magnetization
• Eddy Current Loss: Loss induced by eddy currents generated in magnetic materials under alternating magnetic fields.
• Hysteresis Loss: Arises from the lag of changes in magnetic induction intensity (B) behind changes in magnetic field strength (H); it is approximately equal to the area of the hysteresis loop.
• Residual Loss: Not elaborated in detail, but it is also a component of magnetic loss from dynamic magnetization.
About Eddy Current
• Shielding Effect: Eddy currents can shield the material from internal magnetization by external alternating magnetic fields, causing the external magnetic field strength to decay exponentially with increasing depth and producing a decoupling effect.
• Reduction Approaches: Reducing the material thickness and increasing its resistivity can lower eddy current loss.
About Hysteresis Loss
• Energy Consumption: It refers to the energy consumed when domain walls overcome obstacles such as stress and impurities to undergo irreversible displacement during the material’s magnetization process.
• Calculation: Typically, only eddy current loss and hysteresis loss are considered in loss calculation.
• Frequency Relationship: Under low-frequency and weak-field conditions, eddy current loss is proportional to the square of the frequency, while hysteresis loss is proportional to the frequency.