Electrical Model of Frequency Loss Induced Quench Protection System for High Temperature Superconducting Magnets

Frequency Loss Induced Quench (FLIQ) is an active protection system designed to generate heat from AC losses to uniformly and safely quench a superconducting coil. It drives an imbalance in the transport current between two or more sections of the magnet using the H-bridge design with Insulated Gate Bipolar Transistor (IGBT)s, whose gates are controlled based on the current feedback within its loop. This allows FLIQ to operate at resonance with the frequency of the load. The performance of FLIQ circuit was characterized using simulations to assess the relative effectiveness of the key parameters of voltage, frequency, and time. The results show that the voltage is the most effective parameter. It was shown that with the selection of appropriate values of the parameters, the FLIQ system released sufficient energy into the coil to quench it.