Power Semiconductor Equipment Cooling Methods and Application Criteria

A variety of factors including cost effectiveness, output rating, and reliability influence the choice of cooling method for semiconductor power conversion equipment. For this study, a number of representative cooling systems (air, water, immersion) were evaluated for a 700 V ac to adjustable voltage dc conversion equipment. A transient thermal model of an external pressure-mounted double-side cooled thyristor (such as a Press Pak, Hockey Puk, Disk Pac, etc.) was used to demonstrate the transient time frame over which changes in the cooling system affect the system rating. The systems evaluated provided a range of system performance and demonstrated the need for careful definition of application requirements.