Power supply management apparatus and method thereof

1. An apparatus comprising:

an onboard energy storage device;

an onboard power conversion device configured to be electrically coupled to an external power source for receiving electrical power therefrom; and

at least one drive system electrically coupled to the onboard energy storage device and the onboard power conversion device,

wherein the at least one drive system comprises a traction drive system and a power take-off (PTO) drive system, the traction drive system is configured to receive electrical power cooperatively provided from the onboard energy storage device and the onboard power conversion device for driving movement of the apparatus, and the PTO drive system is configured to receive electrical power cooperatively provided from the onboard energy storage device and the onboard power conversion device for driving movement of at least one implement in association with the PTO drive system,

wherein the onboard energy storage device provides electrical power to the at least one drive system and the onboard power conversion device provides electrical power received from the external power source to the at least one drive system simultaneously, depending on a state of charge of the onboard energy storage device,

and wherein the onboard power conversion device concurrently provides electrical power received from the external power source to the at least one drive system and to the onboard energy storage device;

the apparatus further comprising:

a DC bus coupled to the onboard energy storage device and the onboard power conversion device; and

a traction switch electrically coupled to the DC bus and the traction drive system, wherein when the apparatus is operating in a charging mode, the traction switch is opened to disable the traction drive system, and wherein when the apparatus is operating in a driving mode, the traction switch is closed to allow at least a part of the electrical power provided from the onboard power conversion device to be transferred to the traction drive system via the DC bus and the traction switch; and

a PTO switch electrically coupled to the DC bus and the PTO drive system, wherein when the apparatus is operating in a charging mode, the PTO switch is opened to disable the PTO drive system, and wherein when the apparatus is operating in a driving mode, the PTO switch is closed to allow at least a part of the electrical power provided from the onboard power conversion device to be transferred to the PTO drive system via the DC bus and the PTO switch; and

wherein an internal combustion engine is absent from the apparatus.

2. The apparatus of claim 1 , wherein the apparatus comprises an electric tractor, and the at least one implement comprises at least one of a plow, a forklift, a dump, a shovel, and an excavator.

3. The apparatus of claim 1 , wherein the external power source comprises at least one of a utility power grid, a portable electricity generator, a wind turbine generator, hydro-micro turbine generator, and a solar panel.

4. The apparatus of claim 1 , further comprising:

a direct-current (DC) bus coupled to the onboard energy storage device and the onboard power conversion device; and

an energy storage switch electrically coupled to the onboard energy storage device and the DC bus,

wherein when the apparatus is operating in a charging mode, the energy storage switch is closed to allow at least a part of the electrical power provided from the onboard power conversion device to be transferred to the onboard energy storage device via the DC bus and the energy storage switch.

5. The apparatus of claim 4 , wherein when the apparatus is operating in a driving mode, the energy storage switch is opened to stop charging the onboard energy storage device.

6. The apparatus of claim 5 , further comprising:

a vehicle controller electrically coupled to the energy storage switch, wherein the vehicle controller is configured to send a first switch signal to close the energy storage switch when the apparatus is operating in the charging mode; and

the vehicle controller is further configured to send a second switch signal to open the energy storage switch when the apparatus is operating in the driving mode.

7. The apparatus of claim 4 , wherein when the apparatus is operating in the charging mode, the at least one drive system is disabled.

8. The apparatus of claim 1 , wherein when a state of charge (SOC) of the onboard energy storage device is determined to be below a low-SOC threshold value, an energy transfer link is established between the onboard power conversion device and the onboard energy storage device, such that at least a part of the electrical power provided from the onboard power conversion device is transferred along the energy transfer link to the onboard energy storage device.

9. The apparatus of claim 1 , wherein when a SOC of the onboard energy storage device is determined to be above a high-SOC threshold value, the at least one drive system is driven by a combination electrical power provided from the onboard energy storage device and the onboard power conversion device.

10. The apparatus of claim 1 , wherein during the time period that at least a part of the electrical power provided from the onboard power conversion device is delivered to at least one drive system, at least another part of the electrical power provided from the onboard power conversion device is delivered to charge the onboard energy storage device.

11. The apparatus of claim 1 , further comprising:

an energy storage switch electrically coupled to the onboard energy storage device;

a sensor coupled to an output of the onboard energy storage device; and

a vehicle controller coupled in electrical communication with the energy storage switch and the sensor;

wherein when a sensor feedback signal generated from the sensor and transmitted to the vehicle controller indicates that the onboard energy storage device is over-charged or over-discharged, the vehicle controller sends a control signal to open the energy storage switch.