An Online Thermal Parameter Identification Method for MOSFETs in DC-DC converters

This paper proposes an online algorithm to identify the thermal parameters of power MOSFETs in DC-DC converters using the perturbed inductor current, the measured case temperature, and calculated power dissipation within MOSFET. The junction temperature of power MOSFETs is closely related to the reliability of the converter and highly affected by the thermal parameters. The proposed algorithm identifies the thermal parameters to accurately compute the junction temperature. In the proposed algorithm, the perturbation of inductor current, measurement of the case temperature, and calculated power dissipation are used to achieve the thermal parameters identification without halting the operation of the dc-dc converter. To verify effectiveness of the proposed method, the simulation experiments based on MATLAB/SIMULINK and PLECS are performed on a 480W synchronous buck dc-dc converter.