An active feedback controller for a power supply current of a no-insulation (NI) high-temperature superconductor (HTS) magnet to reduce or eliminate the charging delay of the NI HTS magnet and to linearize the magnet constant.

A current lead assembly for minimizing heat load to a conduction cooled superconducting magnet during a ramp operation is provided. The current lead assembly includes a vacuum chamber having a through hole to enable a first end of a current lead contact to remain outside the vacuum chamber and a second end of the current lead contact to penetrate within the vacuum chamber. A vacuum boundary wall is located between the vacuum chamber and the current lead contact. At least one superconducting magnet is arranged inside of the vacuum chamber and includes a magnet lead. A second end of the current lead contact is coupled to the magnet lead via an internal lead. A vacuum cap is removably disposed to sealingly encompass therein the first end of the current lead contact during a first state of operation. The first end of the current lead contact is arranged to contact a power supply during a second state of operation, wherein the contact occurs exterior the vacuum chamber.

A superconducting magnet apparatus includes a plurality of superconducting magnet coil sections connected in series and housed within a cryogenically cooled, vacuum container. A power source generates a current. A first lead is electrically connected to the superconducting magnet coil sections. A second lead is enclosed entirely within the vacuum container. The second lead has a first section and a second section, and the first section is electrically connected to the power source. The second section is electrically connected to the first lead, and rigidly connected to a linear displacement device enclosed entirely within the vacuum container. The linear displacement device linearly displaces the second section relative to the first section, so that the first section contacts the second section thereby electrically connecting the first and second sections, or by creating a gap between the first section and second section thereby electrically disconnecting the first section from the second section.

Charging method for a superconductor magnet system with reduced stray field, weight and space includes: arranging the system within a charger magnet bore; with T.sub.main>T.sub.main.sup.crit and T.sub.shield>T.sub.shield.sup.crit, applying a current I.sub.charger to the charger magnet and increasing I.sub.charger to a first current I.sub.1>0; lowering a main superconductor bulk magnet temperature T.sub.main to an operation temperature T.sub.main.sup.op, with T.sub.main.sup.op<T.sub.main.sup.crit, while keeping T.sub.shield>T.sub.shield.sup.crit; lowering I.sub.charger to a second current I.sub.2<0, thereby inducing a persistent current IP.sub.main in the main magnet; lowering a shield magnet temperature T.sub.shield to an operation temperature T.sub.shield.sup.op, with T.sub.shield.sup.op<T.sub.shield.sup.crit; increasing I.sub.charger to zero, thereby inducing a persistent current IP.sub.shield in the shield magnet; removing the magnet system from the charger bore, and keeping T.sub.main≤T.sub.main.sup.op with T.sub.main.sup.op<T.sub.main.sup.crit and T.sub.shield≤T.sub.shield.sup.op with T.sub.shield.sup.op<T.sub.shield.sup.crit; where: T.sub.main.sup.crit: main magnet critical temperature and T.sub.shield.sup.crit: shield magnet critical temperature.

A method is provided for magnetic resonance (MR) imaging near metal, including acquiring an image at a first magnetic field from a subject that includes a metal object, acquiring an image at a second magnetic field, and combining the images to provide a corrected image with reduced metal distortion. An MR imaging system for measuring near metal is also provided including a superconducting magnet to provide a magnetic field, a power supply for a current to ramp the magnetic field, a cryocooler in contact with the superconducting magnet, a magnetic field controller programmed to ramp the main magnetic field by adjusting the current generated by the power supply, a radio frequency system for transmitting and receiving signals, and a data acquisition and processing system to receive the MR signals, generate image data sets and combine the image data sets to provide a corrected image having a reduced metal distortion.

A superconducting magnetic energy storage system (SMES). The SMES includes a toroidally wound super conducting magnet having a toroidal magnetic core with a charging winding and a discharging winding. The charging winding and discharging winding are wound on the toroidal magnetic core. The SMES also includes a DC power source, the DC power source operable to provide DC current to the charging winding of the toroidally wound superconducting magnet, and a modulator operably connected to the DC power source and the charging winding, the modulator operable to modulate at least a portion of the DC current applied to the charging winding of the superconducting magnet. The energy is stored in a magnetic field of the superconducting magnet by applying a current to the charging winding of the superconducting magnet, and energy is withdrawn from the magnetic field by a current flowing in the discharging winding.

A method is provided for magnetic resonance (MR) imaging near metal, including acquiring an image at a first magnetic field from a subject that includes a metal object, acquiring an image at a second magnetic field, and combining the images to provide a corrected image with reduced metal distortion. An MR imaging system for measuring near metal is also provided including a superconducting magnet to provide a magnetic field, a power supply for a current to ramp the magnetic field, a cryocooler in contact with the superconducting magnet, a magnetic field controller programmed to ramp the main magnetic field by adjusting the current generated by the power supply, a radio frequency system for transmitting and receiving signals, and a data aquisition and processing system to receive the MR signals, generate image data sets and combine the image data sets to provide a corrected image having a reduced metal distortion.

Systems and methods for rapidly ramping the magnetic field of a superconducting magnet, such as a superconducting magnet adapted for use in a magnetic resonance imaging system, are provided. The magnetic field can be rapidly ramped up or down by changing the current density in the superconducting magnet while monitoring and controlling the superconducting magnet's temperature to remain below a transition temperature. A superconducting switch is used to connect the superconducting magnet and a power supply in a connected circuit. The current generated by the power supply is then adjusted to increase or decrease the current density in the superconducting magnet to respectively ramp up or ramp down the magnetic field strength in a controlled manner. The ramp rate at which the magnetic field strength is changed is determined and optimized based on the operating parameters of the superconducting magnet and the current being generated by the power supply.

A system comprises a superconducting magnet comprising a coil of superconducting material. The coil includes two electrical terminals. The windings of the coil are separated by a metallic conductor. A control circuit is coupled to the two terminals to drive a current through the coil to charge the superconducting magnet and configured to provide a current through the coil that is sufficiently small to avoid a quenching effect of the superconducting magnet but also large enough to charge the magnet within a predetermined time period. A cooling structure is thermally coupled to the coil to remove heat caused by charging the superconducting magnet with the current to allow for the current to be sufficiently large to charge the magnet within the predetermined time period without causing the quenching effect.

A method is provided for magnetic resonance (MR) imaging near metal, including acquiring an image at a first magnetic field from a subject that includes a metal object, acquiring an image at a second magnetic field, and combining the images to provide a corrected image with reduced metal distortion. An MR imaging system for measuring near metal is also provided including a superconducting magnet to provide a magnetic field, a power supply for a current to ramp the magnetic field, a cryocooler in contact with the superconducting magnet, a magnetic field controller programmed to ramp the main magnetic field by adjusting the current generated by the power supply, a radio frequency system for transmitting and receiving signals, and a data aquisition and processing system to receive the MR signals, generate image data sets and combine the image data sets to provide a corrected image having a reduced metal distortion.