Power inductor loss

  • Copper loss P_{Copper}=P_{DCR}+P_{ACR}
    • DC copper loss caused by the DC Resistance (DCR) of the windings. It increases proportionally to the square of the current.
    • AC copper loss caused by the AC Resistance (ACR). The AC resistance depends on the frequency and is based on
      • skin effect: The higher the frequency the lower the skin depth. As the frequency becomes higher, there is a tendency for the current flow to become concentrated in the area near the conductor surface and for the effective resistance value to increase.
      • proximity effect: The proximity effect increases the AC resistance as well. A current driven wire creates a magnetic field around the wire, which also creates a magnetic field around the wire, which also creates eddy currents.
  • Core loss
    • Hysteresis loss
    • Eddy Current loss. Eddy current loss is proportional to the square of the frequency.