The Sensitivity of an Electro-Thermal Photovoltaic DC–DC Converter Model to the Temperature Dependence of the Electrical Variables for Reliability Analyses

Abstract

The operational expenditures of solar energy are gaining attention because of the continuous decrease of the capital expenditures. This creates a demand for more reliable systems to further decrease the costs. Increased reliability is often ensured by iterative use of design for reliability. The number of iterations that can take place strongly depends on the computational efficiency of this methodology. The main research objective is to quantify the influence of the temperature dependence of the electrical variables used in the electro-thermal model on the reliability and the computation time. The influence on the reliability is evaluated by using a 2-D finite elements method model of the MOSFET and calculating the plastic energy dissipation density in the die-attach and the bond wire. The trade-off between computation time of the electro-thermal model in PLECS (4.3, Plexim, Zurich, Switzerland) and generated plastic energy accuracy obtained in COMSOL (5.3, COMSOL Inc., Burlington, MA, USA) is reported when excluding a certain temperature dependence. The results indicate that the temperature dependence of the input and output capacitors causes no change in the plastic energy dissipated in the MOSFET but does introduce the largest increase in computation time. However, not including the temperature dependence of the MOSFET itself generates the largest difference in plastic energy of 10% as the losses in the die are underestimated.

Experimental Characterization and Electro-Thermal Modeling of Double Side Cooled SiC MOSFETs for Accurate and Rapid Power Converter Simulations

“…Additionally, the temperature dependence of SiC MOSFETs is unique,and SiC MOSFETs are susceptible to degradation mechanisms such as dielectric breakdown and some models may not be able to take into account the effects of these mechanisms. In addition, the impact of package and interconnects on the device's behavior, and the impact of the manufacturing process spread on the device's behavior is not always considered in the models [18], [29], VOLUME 11, 2023 [41], [42], [43], [44], [45], [46], [47], [48], [49], [50]. Possible packaging options for SiC MOSFETs in vehicle power electronics applications include plastic packages, ceramic packages, direct bond copper (DBC) packages, silicon nitride (Si3N4) packages, and metal-ceramic packages.…”

Thermo-Mechanical Stress Comparison of a GaN and SiC MOSFET for Photovoltaic Applications

“…Both can be calculated by using the datasheets provided by the manufacturer [24]. Modeling the temperature dependence of these losses is mandatory for reliability analyses according to a previously performed sensitivity analysis [25]. Other temperature dependences in the topology have a negligible impact on the thermo-mechanical degradation of the MOSFET.…”

“…Additional RA-T2X-25E heat sinks have been added in order to keep the junction temperatures of these devices within the operating limits at the maximum input power. The thermal resistances can either be extracted from the datasheets or calculated while using the cross-sectional surface and the thermal conductivity of the materials, as previously demonstrated in [25]. The heat is generated in the die and conducted through the case and heat sink towards either the surrounding air or the PCB.…”

“…This means that only a single temperature conversion is required from the infrared camera in order to measure the actual case temperature. The component case temperatures are logged at steady-state while using a FLIR X6580sc infrared camera with a resolution of 640 by 512 pixels in combination with an infrared window mounted in the door of the climate chamber as done in a previous publication [25]. The junction losses and the ambient temperatures from Section 2.2 were also applied to the FEM model and the resulting simulated case temperatures were compared with the experimentally measured case temperatures in Figure 10.…”