This paper presents an improved thermal design methodology for wind power converters. It combines analysisand experimental thermal design tools, including heat transfer correlations, flow network modeling (FNM), computational fluid dynamics (CFD), and experimental measurement techniques.Moreover, a systemic product development process isintroduced and an effective combination between the product development process and the thermal design methodology isachieved. The draft CFD modeling at the initial design stage isdone. Furthermore, it uses the detailed CFD modeling and experimental measurement techniques to provide a higher degree of accuracy at latter design stages. The key advantage of the improved methodology is its emphasis on the use of varied design tools, each of which is actively applied at its optimal point in the proposed product development process.Thus, during the earlier stages of the product development process, the thermal risk is systematically reduced, and longterm reliability of products is maintained in a higher degree.