Estimation of Semiconductor Power Losses Through Automatic Thermal Modeling

Abstract

Achieving the optimal design of power converters requires a deep understanding of the system's dissipation elements to meet the desired performance and safety standards. Once the power converter is designed, it is of key importance to estimate the actual power losses in the real setup, in order to redesign the power converter or monitor and control the semiconductor power losses. With that purpose, calorimetric techniques have outperformed electrical methods. However, they come with mechanical limitations and depend on analytical electrothermal equivalent circuits. These models are highly topology and technology dependent, often resulting in simplistic representations that underestimate thermal effects or complex sets of differential equations. To overcome these challenges, we present a novel post-design automatic method for characterizing semiconductor power losses through its converter thermal dynamics. Our method is rooted in an optimization program that identifies the optimal discrete-time linear model according to a set of power versus temperature profiles. The proposed approach ensures the accurate identification and integration of desired modeling requirements. The methodology is applicable to any power converter topology, and the derived linear model enables the use of standard control theory techniques for monitorization and control. Experiments with a real power converter validate the proposal's versatility and accuracy.