Electric powertrain and a method of operating the same

An electric powertrain comprising:

• an energy storage system for supplying an electric current, the energy storage system including:
• a first energy storage device operable at a first device voltage;
• a second energy storage device operable at a second device voltage;
• a first switching device selectively controllable between an on-state enabling electrical communication therethrough, and an off-state preventing electrical communication therethrough;
• a second switching device selectively controllable between an on-state enabling electrical communication therethrough, and an off-state preventing electrical communication therethrough;
• and
• a third switching device selectively controllable between an on-state enabling electrical communication therethrough, and an off-state preventing electrical communication therethrough;
• wherein the first switching device, the second switching device, and the third switching device are selectively controllable to provide the electric current at a first system voltage when the first switching device, the second switching device, and the third switching device are controlled to operate in a first operating mode;
• wherein the first switching device, the second switching device, and the third switching device are selectively controllable to provide the electric current at a second system voltage when the first switching device, the second switching device, and the third switching device are controlled to operate in a second operating mode, with the first system voltage being different from the second system voltage;
• and
• wherein the first energy storage device, the second energy storage device, the first switching device, the second switching device, and the third switching device are all integrated into a single pack.

A method of controlling an electric powertrain including an electric machine, an inverter connected to the electric machine, and an energy storage system connected to the inverter, the method comprising:

• providing the energy storage system to include:
• a first energy storage device operable at a first device voltage;
• a second energy storage device operable at a second device voltage;
• a first switching device selectively controllable between an on-state enabling electrical communication therethrough, and an off-state preventing electrical communication therethrough;
• a second switching device selectively controllable between an on-state enabling electrical communication therethrough, and an off-state preventing electrical communication therethrough;
• and
• a third switching device selectively controllable between an on-state enabling electrical communication therethrough, and an off-state preventing electrical communication therethrough;
• controlling the first switching device, the second switching device, and the third switching device to operate in a first operating mode to provide an electric current at a first system voltage when the electric machine is operating at a rotational speed that is less than a first defined threshold;
• and
• controlling the first switching device, the second switching device, and the third switching device to operate in a second operating mode to provide the electric current at a second system voltage when the electric machine is operating at a rotational speed that is greater than the first defined threshold.