Hysteresis Effect Induced Inductance Change and Power Loss for Boost Converter during the Voltage Conversion

From the Joules-Atherton (J-A) model, the sign of magnetization energy loss due to hysteresis at the positive-going magnetic field H is opposite to that at the negative-going magnetic field H , which is +1 if dH/dt > 0 and is -1 if dH/dt < 0. This implies that an inductor has different inductances at the current ramp-up time due to dH/dt>0 and ramp-down time due to dH/dt < 0. However, this phenomenon is never reported until now. In this article, the inductance of an inductor is found which is larger than the intrinsic inductance at the current ramp-up time ( t_ up ) and smaller than the intrinsic inductance at the current ramp-down time ( t_ dn ) for a boost converter during the continuous conduction mode (CCM) voltage converter. Moreover, hysteresis also makes the classical model of the voltage conversion ratio for boost converter design, V_ OUT/V_ IN= 1/(1-D) , invalid since D(t_ up/T ) is not a constant caused by the t_ up and t_ dn varied with the output current of boost converter, where t_ up + t_ dn= T. The hysteresis model aids designers in estimating the behavior of inductor current variations more accurately without having to wait for chip manufacturing and measurement to reveal the actual behavior.