Patent ID: 8136454

Claim:
A battery-powered, all-electric locomotive comprising: a locomotive platform carrying no internal combustion engine on board; a battery assembly including one or more strings of batteries; a plurality of traction motors powered exclusively by the battery assembly to drive the locomotive platform, the plurality of traction motors receiving no power supplied from any power source external to the locomotive during operation; a DC bus coupling the battery assembly to the plurality of traction motors; a battery management system that monitors and equalizes the batteries to maintain a desired state of charge (SOC) and depth of discharge (DOD) for each battery; and a motor control circuitry in cooperation with the battery management system to draw currents, within throttle-dependent limits, from the battery assembly to drive the plurality of traction motors, the motor control circuitry being configured to limit a traction motor armature current to the least of: (a) a target armature current value based on a desired throttle position; (b) an amount needed to maintain a total current of the one or more strings based on the desired throttle position; and (c) a temporarily reduced amount needed to limit a rate of current increase when the throttle position is advanced.