Development of a three-phase cryogenic synchronous rectifier

This thesis details the design, fabrication and testing of prototypes of a three-phase Synchronous Rectifier, Power MOSFETs have been used as rectifying devices for synchronous rectification in combination with the necessary control circuits, Experiments have been performed in four different conditions, passive rectification using the body diodes of the MOSFETs at room temperature and at cryogenic temperature, synchronous rectification at room temperature and at cryogenic temperature. The results of these experiments show that synchronous rectification schemes significantly reduce the on-state voltage drop at room temperature and this reduction is more pronounced if the MOSFETs are cooled with liquid nitrogen. Reduction of the on-state voltage leads to the reduction in conduction losses and improves the power handling capability especially at cryogenic temperatures.