Assignment #12 - Introduction to Power Electronics | ECEN 5797, Assignments of Electrical and Electronics Engineering

Download Assignment #12 - Introduction to Power Electronics | ECEN 5797 and more Assignments Electrical and Electronics Engineering in PDF only on Docsity! 3 2. Inductor of a buck converter (25 points) L C R + V – iL(t) + – 1 2 Vg The buck converter illustrated above operates with the following conditions: Vg = 12 V R = 0.5 V = 5 V fs = 300 kHz The inductor consists of 3 turns #18 AWG copper wire on an ER 14.5/3/7 planar ferrite core, with a 0.24 mm air gap. The core material permeability is very large, and fringing flux may be neglected. The data for this core is listed below Core area Ac = 0.176 cm2 Winding area WA = 0.051 cm2 Mean length per turn MLT = 2.7 cm2 Magnetic path length lm = 1.9 cm For parts (a) and (b), you may neglect all losses. (a) Find the inductance L. (b) Sketch the current waveform iL(t), and find its numerical peak, dc, and rms values. (c) Sketch the waveform of the flux density B (t), and label its maximum and minimum values. (d) Find the core loss, as well as the copper loss predicted by the dc winding resistance. You may neglect proximity losses and the skin effect. The core material exhibits core loss as in the figure at right. ΔB, Tesla 0.01 0.1 0.3 P ow er lo ss d en si ty , W at ts /c m 3 0.01 0.1 1 20 kH z 50 kH z 10 0k H z 20 0k H z 50 0k H z 1M H z 30 0k H z