System and method for quench and over-current protection of superconductor

A rotating electrical machine, comprising:

• a rotor comprising a superconductive rotor coil electrically coupled to an exciter and cooled by a cryogenic coolant;
• and
• a superconductor protection system comprising:
• a current sensor operable to provide a signal representative of current flow through the superconductive rotor coil;
• a temperature sensor operable to provide a signal representative of cryogenic coolant temperature;
• and
• a processor-based device coupled to the current sensor and the temperature sensor, wherein the processor-based device is operable to estimate superconductive rotor coil temperature based on the signal representative of cryogenic coolant temperature and the signal representative of current flow through the superconductive rotor coil.

A protection system for a superconductor, the system comprising:

• a current sensor configured to provide a signal representative of current flowing through the superconductor;
• a temperature sensor configured to provide a signal representative of a cryogenic coolant temperature used to cool the superconductor;
• and
• a control circuit configured to establish an estimated superconductor temperature based on the signal representative of current flowing through the superconductor and the signal representative of a cryogenic coolant temperature used to cool the superconductor, wherein the control circuit is operable to initiate a corrective action to at least one of reducing and stopping the current flowing to the superconductor when the estimated superconductor temperature exceeds a first defined temperature.

A method of protecting a superconductor from a quench condition, the method comprising:

• cooling a superconductor via a cryogenic coolant;
• detecting cryogenic coolant temperature;
• detecting current flow through the superconductor;
• estimating superconductor temperature based on the current flow through the superconductor and the cryogenic coolant temperature;
• and
• comparing an estimated superconductor temperature to a threshold temperature and initiating a corrective action to protect the superconductor when the estimated superconductor temperature exceeds the threshold temperature.

A method of detecting a quench condition in a superconductor, comprising:

• detecting coolant temperature of a cryogenic coolant used to cool the superconductor;
• detecting current flow through the superconductor;
• and
• operating a processor-based device to estimate superconductor temperature based on a thermal model that utilizes the current flow through the superconductor and the cryogenic coolant temperature to estimate the superconductor temperature.

A computer program, comprising:

• a first routine stored in a tangible medium to enable a processor-based device to estimate superconductor temperature based on current flow through the superconductor and superconductor coolant temperature;
• a second routine stored in a tangible medium to enable the processor-based device to estimate superconductor critical current based on the estimated superconductor temperature;
• and
• a third routine stored in a tangible medium to enable the processor-based device to estimate a change in superconductor temperature based on a difference between the current flowing through the superconductor and the estimated critical current for the superconductor.