coreloss

Coreloss refers to the energy dissipated as heat inside the magnetic core of electrical devices such as transformers and inductors when the core is subjected to changing magnetic flux. It is a major source of inefficiency in magnetic circuits and interacts with thermal management and overall device performance.

Coreloss comprises two main components: hysteresis loss and eddy current loss. Hysteresis loss arises from irreversible changes in the magnetic domain structure as the material is alternately magnetized and demagnetized. The energy loss per cycle depends on the material, its microstructure, and the peak flux density, while the total loss scales with the operating frequency. Eddy current loss results from currents induced within the core by the varying flux; these currents flow in loops and dissipate power as heat. Eddy current loss increases with the square of frequency and the square of the flux density and is highly sensitive to the thickness of the conducting paths within the core.

Materials and construction are chosen to minimize coreloss. Laminated steel, amorphous and nanocrystalline alloys, and ferrites reduce eddy currents, while materials with favorable hysteresis characteristics minimize hysteresis loss. Laminations, insulation between layers, and thin cross-sections lower eddy currents; higher-resistivity or insulated particle-based cores also help. At high frequencies, ferrites and other specialized materials are common, offering low losses and suitable magnetic properties.

Core losses are typically specified as a function of frequency and peak flux density, and they are often treated as the sum of hysteresis and eddy current losses (Ph and Pec). Accurate loss modeling informs efficiency calculations, cooling requirements, and material choice in transformers, inductors, motors, and other magnetic components.