Extruded radial fin heat sinks are typically used in power electronics for temperature management. The goal of this study is to compare the temperature predictions of LPTN (Lumped Parameter Thermal Network), Finite element based thermal analysis (using ANSYS Mechanical) and Finite volume based CFD (Computational Fluid Dynamics) & thermal analysis in power electronics hardware. The power electronics hardware under study is used for control of compressors / heaters used in a medical thermal management device. The hardware consists of 2 SCRs (Silicon Controlled Rectifiers) and 2 TRIACs (TRIodes for Alternating Current) arranged in straight in-line configuration with the TRIACs having a higher internal heat generation (1.643E7 W/m3) than the SCRs (4.53E6 W/m3). Each of these four devices is bolted to a separate anodized aluminum heat sink using a TIM (Thermal Interface Material). It was found that CFD based Conjugate Heat Transfer (CHT) analysis with S2S (Surface to Surface) Radiation transfer gave the most accurate thermal predictions (within 6°C). These were comparable to the predictions from 3-D Solid energy equation with uniform convection and S2S radiation. Depending on the availability of computational time and resources, either full CHT study or 3-D Solid energy equation based thermal analysis with uniform convection and S2S radiation is recommended for initial design study.