Patent ID: 8342103

Claim:
A locomotive comprising: a first locomotive platform carrying no internal combustion engine on board; a battery assembly including strings of batteries wherein each said string has batteries connected in series; a plurality of traction motors powered exclusively by the battery assembly to drive the first 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 comprising a plurality of BMS units, each said BMS unit comprising a microcontroller or microprocessor, a charge equalization circuit comprising a bi-directional DC-DC converter operatively connecting to a temporary buffer for battery equalization, and at least one temperature sensor, and each said BMS unit being operatively connected with one of the strings of batteries and configured to: (a) measure electrical parameters including voltage of said string of batteries, (b) monitor temperatures of said string of batteries, and (c) equalize charges among the batteries of said string 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.