Active cooling of metal oxide semiconductor controlled thyristor using venturi flow

A metal oxide semiconductor controlled thyristor (MCT) is a solid-state high-current switching device. Because of its high-current and high-heat dissipation, this device requires an advanced cooling arrangement. A sample MCT device was successfully tested in a conduction mode up to 95 A using a new technique called venturi cooling. Steady-state operational tests were performed under various coolant temperatures and flow rates. The highest device temperature was 168.5 C, whereas the power dissipation and heat flux were 170 W and 257 W/sq cm, respectively. Comparison with a commercial liquid-cooled cold plate showed that the cooling effectiveness is nearly double for the venturi flow. Measured junction-to-case thermal resistance of the MCT was 0.213 C/W for venturi flow compared to 0.421 C/W for the commercial cold plate. Venturi flow cooling is highly recommended for MCT applications. (Author)