US Patent 7110272 Inverter bridge controller implementing short-circuit protection scheme

A fault handling system for short circuit recovery in three-phase multiple-level inverter bridges, used to drive inductive loads, which waits for either desaturation of switches or expiration of a delay period based upon an amount of time before saturated switches are damaged before commanding off switches that are saturated, and which artificially creates a dead-short across the three-phase output to force switches conducting a fault current to desaturate. By delaying the switching-off of the inverter bridge during a fault, waiting for desaturation to occur, the statistical likelihood of switch survival is improved.