Nonlinearity in small planar inductors: experimental characterization using multivariate response surface

This paper presents a procedure to develop a multivariate model of the behavior of planar inductors when subject to high flux density levels using Design of Experiments (DoE) methodology. A Central Composite Design (CCD) is employed to obtain a multivariate equation that shows the interaction between the number of turns, the air gap and the volt-seconds applied to the inductor. A simple and efficient method to determine the value of the effective inductance using a boost converter is also presented. Experimental results using a planar ER18/3.2/10 core are provided, confirming the accuracy of the obtained model.