Methods and systems for charging an electric vehicle

1. An electric vehicle charging system comprising:

a plurality of electric vehicle charging apparatus coupled to, and configured to receive electric power from, a distribution transformer;

a central processing device configured to control operation of said plurality of electric vehicle charging apparatus; and

at least one sensor coupled to said central processing device and configured to provide said central processing device with data, said central processing device further configured to:

determine a present electrical load on the distribution transformer based on the data;

receive a charging request from a first electric vehicle charging apparatus of said plurality of electric vehicle charging apparatus;

determine if providing power to said first electric vehicle charging apparatus will cause the present electrical load on the distribution transformer to exceed a predefined nominal load rating of the distribution transformer;

provide said first electric vehicle charging apparatus with an electric power charging signal if providing power to said first electric vehicle charging apparatus will not cause the present electrical load on the distribution transformer to exceed the predefined nominal load rating of the distribution transformer;

compare the present electrical load to a predefined maximum distribution transformer load rating if it is determined that providing power to said first electric vehicle charging apparatus will cause the present electrical load on the distribution transformer to exceed the predefined nominal load rating of the distribution transformer;

deny service to said first electric vehicle charging apparatus if it is determined that providing power to said first electric vehicle charging apparatus will cause the present load on the distribution transformer to exceed the predefined maximum distribution transformer load rating; and

place the first electric vehicle charging apparatus in a queue.

2. A system in accordance with claim 1 , wherein each of said plurality of electric vehicle charging apparatus comprises a communications device configured to transmit a unique identification signal to said central processing device.

3. A system in accordance with claim 2 , wherein said identification signal uniquely identifies each of said plurality of electric vehicle charging apparatus, said central processing device configured to determine a number of electric vehicle charging apparatus coupled to the distribution transformer based on received identification signals.

4. A system in accordance with claim 1 , wherein said central processing device is further configured to compare the present electrical load to a power available under the predefined nominal load rating for the distribution transformer to determine if providing power to said first electric vehicle charging apparatus will cause the present electrical load on the distribution transformer to exceed the predefined nominal load rating of the distribution transformer.

5. An electric vehicle charging system comprising:

a plurality of electric vehicle charging apparatus coupled to, and configured to receive electric power from, a distribution transformer;

a central processing device configured to control operation of said plurality of electric vehicle charging apparatus; and

at least one sensor coupled to said central processing device and configured to provide said central processing device with data, said central processing device further configured to:

determine a present electrical load on the distribution transformer based on the data;

receive a charging request from a first electric vehicle charging apparatus of said plurality of electric vehicle charging apparatus, said first electric vehicle charging apparatus comprises an input/output device configured to display at least one charging option to a consumer and to receive at least one charging selection from the consumer;

determine if providing power to said first electric vehicle charging apparatus will cause the present electrical load on the distribution transformer to exceed a predefined nominal load rating of the distribution transformer;

provide said first electric vehicle charging apparatus with an electric power charging signal if providing power to said first electric vehicle charging apparatus will not cause the present electrical load on the distribution transformer to exceed the predefined nominal load rating of the distribution transformer;

compare the present electrical load to a predefined maximum distribution transformer load rating if it is determined that providing power to said first electric vehicle charging apparatus will cause the present electrical load on the distribution transformer to exceed the predefined nominal load rating of the distribution transformer;

transmit a charging option signal to said first electric vehicle charging apparatus if it is determined that providing power to said first electric vehicle charging apparatus will not cause the present load on the distribution transformer to exceed the predefined maximum distribution transformer load rating, wherein upon receipt of the charging option signal, said input/output device displays the at least one charging option to the consumer; and

receive, from said input/output device, at least one of a charge-delay signal corresponding to a charge-delay selection and a charge-now signal corresponding to a charge-now selection.

6. A system in accordance with claim 5 , wherein said central processing device is further configured to determine an energy rate associated with the charge-now selection and to include the energy rate within the charging option signal provided to said input/output device.

7. A system in accordance with claim 6 , wherein the energy rate associated with the charge-now selection is greater than an energy rate associated with the charge-delay selection, wherein the energy rate associated with the charge-now selection is calculated to offset a loss in the value of the distribution transformer caused by the present load on the distribution transformer exceeding the predefined nominal load rating of the distribution transformer.

8. A method for controlling charging of an electric vehicle using an electric vehicle charging apparatus coupled to a distribution transformer, said method comprising:

determining an electrical load on the distribution transformer;

providing the electric vehicle charging apparatus with an electric power charging signal if providing power to the electric vehicle charging apparatus will not cause the electrical load on the distribution transformer to exceed a predefined nominal load rating of the distribution transformer;

determining if providing power to the electric vehicle charging apparatus will cause the load on the distribution transformer to exceed the predefined nominal load rating of the distribution transformer;

comparing the electrical load on the distribution transformer to a predefined maximum distribution transformer load rating if it is determined that providing power to the electric vehicle charging apparatus will cause the load on the distribution transformer to exceed the predefined nominal load rating of the distribution transformer; and

denying service to the electric vehicle charging apparatus if it is determined that providing power to the electric vehicle charging apparatus will cause the load on the distribution transformer to exceed the predefined maximum distribution transformer load rating and placing the electric vehicle charging apparatus in a queue.

9. A method in accordance with claim 8 , further comprising collecting input data and registering each electric vehicle charging apparatus coupled to the distribution transformer.

10. A method in accordance with claim 8 , wherein determining if providing power to the electric vehicle charging apparatus will cause the load on the distribution transformer to exceed the predefined nominal load rating comprises comparing the electrical load on the distribution transformer to a power available under the predefined nominal power rating for the distribution transformer.

11. A method in accordance with claim 8 , further comprising at least one of:

delaying service to the electric vehicle charging apparatus if it is determined that providing power to the electric vehicle charging apparatus will not cause the load on the distribution transformer to exceed the predefined maximum distribution transformer load rating and a charge-delay signal is received from the electric vehicle charging apparatus; and

providing the electric power charging signal if it is determined that providing power to the electric vehicle charging apparatus will not cause the load on the distribution transformer to exceed the predefined maximum distribution transformer load rating and a charge-now signal is received from the electric vehicle charging apparatus.

12. A method in accordance with claim 8 , further comprising determining a charging order for the plurality of electric vehicles based at least partially on a comparison of the electrical load on the distribution transformer to at least one of the power available under the predefined nominal power rating for the distribution transformer and the predefined maximum distribution transformer load rating.