Simulation of Electrothermal Transient Responses in Power PCB Modules Using Comsol, Spice, and Asonika-TM

Large temperature jumps in the structures of power semiconductor devices when they are turned on and off significantly reduce the reliability of power circuits. The widely used electrothermal modeling approaches for thermal circuits have a number of disadvantages: the use of interconnected Spice simulators and the numerical 3D thermal field modeling tool requires a detailed description of 3D structures and significant computer time; the use of only Spice-like simulators of electrical circuits for mixed electrothermal modeling requires the creation of electrothermal models of power components and significant CPU time costs due to the large difference in the time constants of the electrical and thermal parts. In this study, an improved scheme of multilevel automated electrothermal modeling and simulation of power electronic components using the Comsol software at the semiconductor device level, Spice simulation at the circuit level, and the Asonika-TM system at the printed circuit board (PCB) level is proposed and implemented. The developed additional software tools for the implementation of the proposed route are described, providing automation of the power calculation processes of components of power circuits, transferring the obtained values to a thermal simulation tool, and forming electrothermal models of the circuit components. The correctness of the proposed modeling scheme is confirmed by the results of thermal-imaging analysis using an IR camera. The effectiveness of the proposed methodology is demonstrated through the example of a real PCB design with high-power MOSFETs for controlling a power stepper motor. In the analyzed circuit, a possible thermal failure of the output DMOSFETs due to their overheating is revealed. To improve the conditions for reducing their temperature, it is proposed to use a larger electrode radiator with lower thermal resistance.