The invention relates to a superconducting electrical switch. The switch comprises two parallel branches of superconducting material in a loop, and a magnetic field generator which generates a time-varying magnetic field through the loop in a direction generally parallel to the axis of the loop. The magnetic field generator is selectively activated and de-activated to switch the electrical switch between a low-resistance state and a higher-resistance state. In the low-resistance state, there is no magnetic field through the loop and transport current flows through the loop. In the higher-resistance state, a magnetic field through the loop induces a screening current such that the sum of the transport current and the screening current is substantially equal to the critical current or is greater than the critical current of the superconducting material. The switch may be used in, for example, a rectifier or fault current limiter.

A persistent current switch includes a superconducting wire, a heater, and an insulating member. The superconducting wire includes a substrate and a superconducting layer provided on the substrate. The superconducting layer includes a first principal surface facing the substrate and a second principal surface on an opposite side of the first principal surface. The heater is disposed only on the second principal surface side with respect to the superconducting layer. The insulating member is provided between the second principal surface of the superconducting layer and the heater.

A persistent current switch includes a superconducting wire including a substrate and a superconducting layer disposed on the substrate, and a heater. The superconducting wire includes a surface including a first portion and a second portion that are disposed apart from each other along a longitudinal direction of the superconducting wire. The first portion and the second portion face each other. The heater is sandwiched between the first portion and the second portion.

A device comprising a high temperature superconductor, HTS, circuit; wherein the HTS circuit comprises: a quenchable section comprising HTS material and connected in series to other elements of the HTS circuit, the HTS material comprising a stack of HTS takes comprising at least one HTS tape; the device further comprising: a quenching system configured to quench the HTS material in the quenchable section; a quench protection system configured to detect temperature rises in the HTS circuit and, in response to detection of a temperature rise, cause the quenching system to quench the superconducting material in the quenchable section in order to dump stored magnetic energy from the HTS circuit into the quenchable section; wherein the HTS circuit is configured such that, when in use, the magnetic field on the or each HTS tape is substantially parallel to a a-b plane of the HTS tape, and the quenching system is configured to quench the HTS material by producing an additional magnetic field along the length of the or each HTS tape within the quenchable section, such that the additional magnetic field has a component perpendicular to the a-b plane of the HTS tape.

A radio frequency-assisted fast superconducting switch is described. A superconductor is closely coupled to a radio frequency (RF) coil. To turn the switch “off,” i.e., to induce a transition to the normal, resistive state in the superconductor, a voltage burst is applied to the RF coil. This voltage burst is sufficient to induce a current in the coupled superconductor. The combination of the induced current with any other direct current flowing through the superconductor is sufficient to exceed the critical current of the superconductor at the operating temperature, inducing a transition to the normal, resistive state. A by-pass MOSFET may be configured in parallel with the superconductor to act as a current shunt, allowing the voltage across the superconductor to drop below a certain value, at which time the superconductor undergoes a transition to the superconducting state and the switch is reset.

A rotor for an electrical machine is disclosed herein. The rotor includes a rotor housing, a winding carrier arranged therein, at least one first axial connecting element mechanically interconnecting the winding carrier and the rotor housing, and a superconducting rotor winding configured to produce a magnetic field. The rotor winding is mechanically retained by the winding carrier and is part of a self-contained circuit inside the rotor in which circuit a continuous current may flow. The self-contained circuit has a continuous current switch with a switchable conductor section that may be switched between a superconducting state and a normally conducting state. The switchable conductor section is arranged on the first axial connecting element. A machine including the rotor and a method for operating the rotor is also disclosed herein.

A persistent current switch system is presented. One embodiment of the persistent current switch system includes a vacuum chamber having a winding unit and dual cooling paths. The dual cooling paths are configured to circulate a coolant flow. The dual cooling paths are defined by a first cooling path and a second cooling path. The first cooling path includes a solid thermal component disposed in direct contact with the winding unit and the second cooling path includes a cooling tube disposed in direct contact with the winding unit and configured to circulate a coolant therein. The dual cooling paths cool the temperature of the winding unit below the threshold temperature to transition the persistent current switch system from the first mode to the second mode. A method of for cooling a winding unit in a persistent current switch system and a switching system including dual cooling paths are also disclosed.

There is described a device for controlling an amount of current within a power distribution network by manipulating the amount of magnetic flux in the device and thus the impedance experienced by the power distribution network across the device. This is achieved by winding a plurality of coils about a magnetically permeable core and by providing the device with a magnetically permeable bridge element that is movable between a fully-open position at which the net magnetic flux generated in the core by alternating currents in each coil is zero, and a fully-closed position at which a net magnetic flux is present in the core.

A device comprising a high temperature superconductor, HTS, circuit; wherein the HTS circuit comprises: a quenchable section comprising HTS material and connected in series to other elements of the HTS circuit, the HTS material comprising a stack of HTS takes comprising at least one HTS tape; the device further comprising: a quenching system configured to quench the HTS material in the quenchable section; a quench protection system configured to detect temperature rises in the HTS circuit and, in response to detection of a temperature rise, cause the quenching system to quench the superconducting material in the quenchable section in order to dump stored magnetic energy from the HTS circuit into the quenchable section; wherein the HTS circuit is configured such that, when in use, the magnetic field on the or each HTS tape is substantially parallel to a a-b plane of the HTS tape, and the quenching system is configured to quench the HTS material by producing an additional magnetic field along the length of the or each HTS tape within the quenchable section, such that the additional magnetic field has a component perpendicular to the a-b plane of the HTS tape.

A persistent current switch system is presented. One embodiment of the persistent current switch system includes a vacuum chamber having a winding unit and dual cooling paths. The dual cooling paths are configured to circulate a coolant flow. The dual cooling paths are defined by a first cooling path and a second cooling path. The first cooling path includes a solid thermal component disposed in direct contact with the winding unit and the second cooling path includes a cooling tube disposed in direct contact with the winding unit and configured to circulate a coolant therein. The dual cooling paths cool the temperature of the winding unit below the threshold temperature to transition the persistent current switch system from the first mode to the second mode. A method of for cooling a winding unit in a persistent current switch system and a switching system including dual cooling paths are also disclosed.