Hardware Design and Test of a Cryogenic Boost Chopper Under 77K

Hardware design and test of a cryogenic boost chopper under 77K are presented. Instead of using one transistor and one diode in conventional chopper, the new cryogenic boost chopper is integrated with two metal-oxide semiconductor field-effect transistors (MOSFETs). An experimental setup is built with one main circuit board, one drive circuit board and one capacitor board. The test results show that the on-state resistance of one cryogenic MOSFET unit is reduced from about $0.65 \mathrm {m}\Omega $ at 300 K to about $0.33 \mathrm {m}\Omega $ at 77 K. The tested operating efficiency is rated at about 96.6% under 1 kHz PWM control and about 95.3% under 5 kHz PWM control. Therefore, the proposed cryogenic chopper can be well expected to high-efficiency power conversion.