Feedforward current control of MRI magnet with power supply driven operation

Abstract

Abstract We have been developing a conduction cooled 3T HTS(REBCO)-MRI system. The prototype system of 100 mm DSV (diameter spherical volume) was designed and made.The MRI image of a mouse fetus (25 mm long) was obtained successfully with 2.9 T under a power supply driven operation. However, the HTS(ReBCO)-MRI magnet still had a considerable magnetic field fluctuation for clear MRI imaging due to a long-lasting attenuation of screening current induced on the superconducting tapes. To solve this problem, we introduced a power supply system consists of a exciter power supply and a small trimming current supply, which compensates the magnetic field deviation due to the screening current, in parallel. We measured and evaluated the magnetic field stability of a commercial 3T-LTS-MRI magnet under both the power supply driven operation with proposed system and the persistent current operation. The availability of the power supply system was discussed using an experimental HTS-MRI system.