System for optimizing the charging of electric vehicles using networked distributed energy storage systems
Embodiments of the present invention include control methods employed in multiphase distributed energy storage systems that are located behind utility meters typically located at, but not limited to, medium and large commercial and industrial locations. Some embodiments of the invention use networked multiphase distributed energy storage systems located at an electric load location or installed at interconnection points along the electric power distribution grid to provide a means for balancing the load created from an electric charging station, which are adapted to transfer power between one or more electric vehicles and the electric power grid.
1. A system for managing power, comprising:
a first storage device that is in electric communication with an electric power line that is coupled to an electric power distribution grid, wherein the first storage device comprises a first energy source and a first bidirectional power converter that is coupled between the first energy source and the electric power line;
a first sensor configured to monitor fluctuations in an amount of power flowing through the electric power line to or from the electric power distribution grid;
an electric vehicle charging station having one or more electrical connections that are coupled to the electric power line; and
a first controller that is in communication with the first bidirectional power converter and the first sensor, and is configured to control a transfer of energy between the electric power line and the first energy source through the first bidirectional power converter in response to the fluctuations in the amount of power flowing through the electric power line to or from the electric power distribution grid, wherein the electric power line comprises a first phase and a second phase, and the first controller is configured to maintain a level of balance between transfers of energy to or from the electric power distribution grid via the first phase and the second phase, wherein the first bi-directional power converter and the one or more electrical connections of the electric vehicle charging station are coupled to the first phase, and wherein the first controller maintains the level of balance by causing, in response to a change in a power demand on the first phase by the electric vehicle charging station, the first energy source to transfer energy to or from at least one of the first phase or the second phase of the electric power line.
2. The system of claim 1 , further comprising:
a second energy storage device that is in electric communication with the electric power line, wherein the second energy storage device comprises a second bidirectional power converter that is coupled between the electric power line and the first energy source or a second energy source,
wherein the first controller is further configured to control the transfer of energy between the electric power line and the second bidirectional power converter.
3. The system of claim 2 , wherein the first or second energy sources comprise a battery.
4. The system of claim 1 , wherein a separate power source is coupled to the electric power line, wherein the separate power source comprises a wind turbine or a solar cell.
5. The system of claim 4 , wherein the first bidirectional power converter is configured to receive power delivered from the separate power source and deliver the received power to the first energy source.
6. The system of claim 1 , further comprising:
a second energy storage device that is in electric communication with the electric power distribution grid, wherein the second energy storage device comprises a second bidirectional power converter that is coupled between the electric power distribution grid and a second energy source; and
an operations center that is in communication with the first and second energy storage devices,
wherein the operations center is configured to control the transfer of energy between the electric power line and the first bidirectional power converter and the second bidirectional power converter and the electric power distribution grid.
7. The system of claim 1 , further comprising:
an optimization engine configured to receive one or more external inputs and create a set of operating parameters based on the one or more external inputs, and
the first controller is further configured to receive the created operating parameters and use the operating parameters to control an amount of energy flowing through a first phase of the electric power line below a threshold value.
8. The system of claim 7 , wherein the set of operating parameters are derived from simulations of energy use at the electric load location, and the simulations are performed by the optimization engine.
9. The system of claim 7 , wherein the one or more external inputs are selected from a group consisting of weather information, sunrise and sunset information, power usage cost information, utility's billing period, geographic location, local solar production, local incident light, customer type, electric load location building specifications, grid operator data and time data.
10. The system of claim 7 , wherein the first controller comprises a set-point controller configured to vary the threshold value.
11. The system of claim 1 , further comprising:
an optimization engine configured to receive one or more external inputs and create one or more operating control curves that represent one or more time-varying threshold values based on the one or more external inputs,
wherein the first controller is configured to
receive the one or more operating control curves,
compare the one or more operating control curves to information received from the first sensor and the first energy source, and
control a transfer of energy through the electric power line from or to the first energy source based on the comparison so that the amount of power flowing through the electric power line from the electric power distribution grid does not exceed the one or more time-varying threshold values represented by the one or more operating control curves.
12. The system of claim 1 , wherein the first controller is configured to control the transfer of energy between the electric vehicle charging station and the first energy source to cause the amount of power flowing through the electric power line from the electric power distribution grid not to exceed one or more threshold values.
13. The system of claim 1 , wherein the fluctuations in the amount of power flowing through the electric power line are caused by at least one of an electric vehicle beginning to receive energy from the electric vehicle charging station, an electric vehicle increasing an amount of energy received from the electric vehicle charging station, an electric vehicle no longer receiving energy from the electric vehicle charging station, and an electric vehicle decreasing an amount of energy received from the electric vehicle charging station.
14. The system of claim 1 , wherein the one or more electrical connections of the electric charging station are coupled to the first phase, and a second bidirectional power converter that is coupled to a second energy source is coupled to the second phase, and wherein the first controller is configured to maintain the level of balance by causing, in response to a change in power demands on the first phase by the electric vehicle charging station, the second energy source to transfer energy to or from the second phase of the electric power line through the second bidirectional power converter.
15. A method of managing power at a site, comprising:
delivering power from an electric power line, which is coupled to an electric power distribution grid, to an electrical vehicle in an electric vehicle charging station;
monitoring a flow of the delivered power transmitted through the electric power line to or from the electric power distribution grid; and
controlling, by a first controller, a transfer of power between a first energy storage device and the electric vehicle charging station based on data received by monitoring the delivered power transmitted through the electric power line in response to fluctuations in an amount of power flowing through the electric power line to or from the electric power distribution grid, wherein the electric power line comprises a first phase and a second phase, and the first controller is configured to maintain a level of balance between transfers of energy to or from the electric power distribution grid via the first phase and the second phase, wherein the first energy storage device and the electric vehicle charging station are coupled to the first phase, and wherein the first controller is maintains the level of balance by causing, in response to a change in a power demand on the first phase by the electric vehicle charging station, the first energy storage device to transfer energy to or from at least one of the first phase or the second phase of the electric power line.
16. The method of claim 15 , wherein the first energy storage device comprises a first energy source and a first bidirectional power converter that is coupled between the first energy source and the electric power line.
17. The method of claim 15 , wherein controlling the transfer of power further comprises controlling the transfer of power between a second energy storage device and the electric power line based on data received by monitoring the flow of the delivered power transmitted through the electric power line.
18. The method of claim 17 , wherein the second energy storage device comprises a second energy source and a second bidirectional power converter that is coupled between the second energy source and the electric power line.
19. The method of claim 17 , wherein transferring power between the second energy storage device and the electric power line further comprises:
controlling the transfer of power between the second energy storage device and the electric power line based on a command sent from an operations center that is in communication with the first and second energy storage devices.
20. The method of claim 15 , further comprising:
monitoring a first rate of energy transfer flowing through the electric power line from the electric power distribution grid, wherein the electric power line is coupled to an electric meter;
receiving a first set of operating parameters that are created based on one or more received external inputs; and
based on the first set of operating parameters, varying the energy transfer from the first energy storage device to the electric power line to cause the first rate of energy transfer to remain below a threshold value,
wherein the threshold value varies with time.
21. The method of claim 20 , wherein the one or more external inputs are received by a processor configured to determine the first set of operating parameters and are selected from a group consisting of weather information, sunrise and sunset information, power usage cost information, utility's billing period, geographic location, local solar production, local incident light, customer type, building specifications, grid operator data, and time data.
22. The method of claim 20 , wherein the method further comprises:
transmitting information used to control the first rate of energy transfer to an optimization engine;
receiving a second set of operating parameters from the optimization engine, wherein the second set of operating parameters are based on the transmitted information determined by the optimization engine; and
controlling a second rate of energy transfer based on the second set of operating parameters.