Real-Time Discrete Electrothermal Model of Dual Active Bridge Converter for Photovoltaic Systems

Renewable energy systems have stochastic generation profiles, which affect the performance of the power electronic converters in these systems, especially due to the excessive thermal cycling. In particular, the power semiconductor devices, the most vulnerable components in the power electronic converters, with excessive variation in the junction temperature have reduced lifetime and reliability. Simulating the thermal behaviour of the power devices to study the variations for long periods is not feasible with traditional simulation tools. Consequently, real-time simulations are carried out in such situations. This article presents a real-time discrete electro-thermal model of the dual active bridge converter operating in a photovoltaic system to study the junction temperature variations of the SiC MOSFETs. This model is realized using a low-cost development board with a real-time dual-core microcontroller. This model can subsequently be used to complement the real-time tuning of smart gate drivers to enhance the performance of the SiC MOSFETs. The real-time model is based on experimental data and its performance has been validated using commercially available simulation software.