Measurement set-up to characterize the current dependent inductivity of nonlinear inductances

Magnetics are important key components in the field of power electronics. The use of nonlinear effects of inductors and transformers gives a great opportunity of improving the performance of switch mode power supplies. For an optimal design the material parameters have to be known. However, required information is hardly given in data sheets. Therefore, additional characterization measurements are necessary. This paper presents a measurement set-up to determine the current dependent inductivity of inductors. Two different definitions for the nonlinear inductance are introduced and used for the calculation of the current dependent behavior of nonlinear inductors. The data from one single measurement is sufficient in order to get the current dependent inductivity for the whole dynamic range. Different measurement set-ups are introduced and discussed with all their advantages and disadvantages. The final measurement set-up affords an effective way to determine the whole current dependent behavior of the nonlinear inductance properly.