Cryogenic Low-Voltage/High-Current DC Power Source Using Multi-Parallel-Connected MOSFETs

The authors have proposed a cryogenic low-voltage/high-current DC power source using multi-parallel-connected MOSFETs for an excitation power source of superconducting coils. It has been confirmed that the power source can operate at 77 K in liquid nitrogen bath. The fundamental idea and some experimental results are presented. The experiment using 200 MOSFETs connected in parallel are carried out. The forward-direction voltage drop at 77 K has been measured. The excitation current of the superconducting coil can be increased and decreased arbitrarily. The experimental results show good prospect of this type of DC power source not only for the excitation of superconducting coils but also for the forced discharging of the coils.