Abstract: A hybrid electric vehicle drive system comprises a first power bus electrically coupled to a motive power subsystem and a drive wheel propulsion assembly; a second power bus electrically coupled to the first power bus and a plurality of energy storage subsystems, wherein the first power bus is configured to allow electrical power to be transmitted among the motive power subsystem, the drive wheel propulsion assembly, and the second power bus, and wherein the second power bus is configured to allow electrical power to be transmitted among the plurality of energy storage subsystems and the first power bus.