Improved Dynamic Ripple-Based Modeling Technique for a Toroid Inductor in PFC Rectifiers

In order to precisely predict the PFC choke inductance and its losses, a dynamic ripple-based inductor modeling technique is proposed considering the real-time current ripple over each switching cycle. The realistic inductor model is synthesized considering the operation temperature, instantaneous current magnitude, and $\mathbf{flux}$ density. Three factors are investigated: (i) the non-linearity of the inductor material; (ii) the switching frequency components in the input current; and (iii) the time variation of the duty cycle. Thus, a function to accurately compute real-time inductance is obtained. To validate the proposed model, simulation studies and experiments are conducted using a single-phase totem-pole PFC rectifier. The theoretical prediction exhibits good agreement with the simulation result with 10% error. It is experimentally verified that the real-time measured inductance matches with the model-predicted inductance at 1 kW output power.