Maintenance Time-Constrained Turn-to-Turn Short Circuit Current Management Framework Considering Electrical and Thermal Limits Using RUL and Parameter Estimation in PMSG

The drive for fully electric aircraft and marine system relies on availability and reliability of generating units. Optimal fault management systems are required for continuous operation until the mission is accomplished. The turn-to-turn short-circuit (TTSC) current injection method leads to the initialization of irreversible demagnetization and further degrades the winding insulation. This article proposes a new framework for optimal current injection during TTSC fault condition with objective of maintaining the remaining useful life until the generator maintenance is triggered. A novel way to include the thermal constraint is presented considering the magnetic density limitation on the knee point of magnet, along with proposed fault indicator and magnet temperature calculation. A safe operating region is established in the generator capability curve and variation due to electrical and thermal limits are updated in real time for three-stage successive relaxation optimization to dispatch optimal current. Finite element method-based simulation and experimental testbed are used to validate the proposed framework. The result confirm the availability of generating unit with 36% increase in remaining useful life for 5% short with fault severity of 1
$\Omega$
. Further, the proposed framework can operate the machine at rated and lower power rating based on machine condition without compromising on the load.