The Alcator C-MOD power system

The 14 magnets of the Alcator C-MOD device require delivery of over 500 MJ in a few seconds. Peak powers approaching 300 MW will be delivered from the upgraded 225-MVA alternator used to power the Alcator C device. Most magnets have dedicated power-conversion systems in order to maximize flexibility and to allow operation with a single-null divertor. Details of the power-system design are presented. The toroidal-field conversion system features 260-kA output coupled with an autotap changing design to increase the power factor. The 50-kA ohmic heating (OH) system utilizes a single DC interrupter to switch three OH magnets and three OH converters. The vertical position control system uses a combination of fast, chopper-type supplies and conventional line-commutated converters to combine quick response with low cost. The radial position control system utilizes a reconfigured Alcator C-era OH supply in combination with surplus DC traction motors outfitted with flywheels