Measurement of core losses in toroidal inductors with different magnetic materials
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Magnetic materials are used in the manufacturing of transformers, electrical machines, converters and inductors. The losses of the magnetic materials affect the performance of the electromagnetic devices. The magnetic components play an important role in dissipating the core losses in power electronics devices. Measuring the losses in the magnetic materials is necessary since this data can then be used to identify the eddy-current and hysteresis loss models. The core loss is produced due to the realignment of magnetic domains and wall movements. The eddy currents are caused by the non-zero conductivity of material under an alternating external magnetic field. The eddy currents and hysteresis loss are the origin of core losses. The B-H loops measurement technique is the common approach for measuring the core losses. In this approach, two windings are used for the test core. The main benefit of this approach is that the measurements do not include the copper losses. Since the voltage is measured at the secondary winding, so the voltage drop across the resistance of the primary winding will not affect the measurement results. This thesis investigated the core losses in soft magnetic materials, for example ferrite, molypermalloy powder (MPP), nanocrystalline and amorphous. The measurements were taken under the sinusoidal voltage excitation up to a frequency of 1 kHz. The effects of temperature were not considered in the core loss measurements, which may have influenced the measured results. A comparison of the core losses under different magnetic field density and frequencies is presented. The experimental data showed that nanocrstalline material has the lowest losses whereas amorphous has the highest core losses. The ferrite material has almost double the losses as compared to nanocrystalline. On the other hand, it has been noticed that MPP core shows some variation in the results due to the temperature rise in the core.