Harmonic winding loss in buck DC-DC converter for discontinuous conduction mode

This study presents a general expression for the inductor winding power loss for periodic non-sinusoidal current waveform. Dowell´s equation is used to determine the winding resistance because of eddy currents as a function of frequency. Both skin and proximity effects are taken into account. Fourier series of the triangular inductor current waveform in non-isolated DC´DC power converters and the winding resistance are used to determine the winding power loss at various harmonics. The harmonic winding loss factor FRh is introduced. The theory is illustrated by the case study of the buck converter operating in discontinuous conduction mode. Plots of the winding power losses are given as functions of the output power and the DC input voltage.