Grid regulation services for energy storage devices based on grid frequency

• US 9,753,440 B2
• Filed: 06/04/2013
• Issued: 09/05/2017
• Est. Priority Date: 04/06/2010
• Status: Active Grant

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: Pratt, Richard M., Hammerstrom, Donald J., Kintner-Meyer, Michael C. W., Tuffner, Francis K.
• Primary Examiner(s): JARRETT, RYAN A
• Application Number:
  US13/909,893
• Publication Number:
  US 20130268132A1
• Time in Patent Office: 1,554 Days
• Field of Search: None
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/70 Interactions with external data bases, e.g. traffic centres
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 2250/12 by confirmation, e.g. of the input
• CPC Class Codes: B60L 2260/58 Departure time prediction
• CPC Class Codes: B60L 53/16 Connectors, e.g. plugs or sockets, specially adapted for charging electric vehicles
• CPC Class Codes: B60L 53/305 Communication interfaces
• CPC Class Codes: B60L 53/51 Photovoltaic means
• CPC Class Codes: B60L 53/53 Batteries
• CPC Class Codes: B60L 53/56 Mechanical storage means, e.g. fly wheels
• CPC Class Codes: B60L 53/63 in response to network capacity
• CPC Class Codes: B60L 53/65 involving identification of vehicles or their battery types
• CPC Class Codes: B60L 53/68 Off-site monitoring or control, e.g. remote control
• CPC Class Codes: B60L 55/00 Arrangements for supplying energy stored within a vehicle to a power network, i.e. vehicle-to-grid [V2G] arrangements
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: G05B 13/02 electric
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 13/00 Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
• CPC Class Codes: H02J 13/00006 : characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
• CPC Class Codes: H02J 3/241 : The oscillation concerning frequency
• CPC Class Codes: H02J 3/322 : the battery being on-board an electric or hybrid vehicle, e.g. vehicle to grid arrangements [V2G], power aggregation, use of the battery for network load balancing, coordinated or cooperative battery charging
• CPC Class Codes: H02J 7/0068 : Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: Y02B 90/20 : Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y02E 60/00 : Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 : Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 10/126 : the energy generation units being or involving electric vehicles [EV] or hybrid vehicles [HEV], i.e. power aggregation of EV or HEV, vehicle to grid arrangements [V2G]
• CPC Class Codes: Y04S 10/14 : Energy storage units
• CPC Class Codes: Y04S 30/12 : Remote or cooperative charging
• CPC Class Codes: Y04S 30/14 : Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing
• CPC Class Codes: Y04S 40/12 : characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment

Abstract

Disclosed herein are representative embodiments of methods, apparatus, and systems for charging and discharging an energy storage device connected to an electrical power distribution system. In one exemplary embodiment, a controller monitors electrical characteristics of an electrical power distribution system and provides an output to a bi-directional charger causing the charger to charge or discharge an energy storage device (e.g., a battery in a plug-in hybrid electric vehicle (PHEV)). The controller can help stabilize the electrical power distribution system by increasing the charging rate when there is excess power in the electrical power distribution system (e.g., when the frequency of an AC power grid exceeds an average value), or by discharging power from the energy storage device to stabilize the grid when there is a shortage of power in the electrical power distribution system (e.g., when the frequency of an AC power grid is below an average value).

Claims

1. A method, comprising:

using a computer processor, evaluating second data representing status of an energy storage device to make a determination whether the energy storage device has adequate state of charge for a discharging operation;

if the determination indicates that the energy storage device has adequate state of charge for a discharging operation, then selecting a discharging rate proportionally scaled based on an average discharge rate for a bi-directional charging system, the discharging rate being clamped between a maximum discharging rate and a zero discharging rate for the bi-directional charging system, the selected discharging rate being based on an average load rate for the bi-directional charging system and on first data representing one or more electrical characteristics of an electrical power distribution system, the bi-directional charging system being operable to charge or discharge the energy storage device; and

generating a regulation signal for causing the bi-directional charging system to discharge the energy storage device, the regulation signal being based at least in part on the selected discharging rate.

2. The method of claim 1, wherein the first data includes frequency data representing an instantaneous frequency measurement of the electrical power distribution system.

3. The method of claim 2, further comprising computing an average frequency from the frequency data.

4. The method of claim 1, further comprising generating a regulation signal for causing the bi-directional charging system to charge the energy storage device, the regulation signal being based at least in part on the selected discharging rate.

5. The method of claim 1, wherein the first data includes frequency data representing an instantaneous frequency of the electrical power distribution system and an average frequency of the electrical power distribution system.

6. The method of claim 1, further comprising receiving the second data representing the status of the energy storage device.

7. The method of claim 6, wherein the second data includes data representing a state-of-charge of the energy storage device.

8. The method of claim 1, further comprising receiving third data representing a desired final charging time, and wherein the selecting is further based, at least in part, on the third data.

9. The method of claim 1, further comprising receiving an upper frequency parameter defining an over-frequency event of the electrical power distribution system, a lower frequency parameter defining an under-frequency event of the electrical power distribution system, and wherein the selecting is based at least in part on one or more of the upper frequency parameter or the lower frequency parameter.

10. The method of claim 1, wherein the second data includes data representing an actual charging or discharging rate of the energy storage device.

11. The method of claim 1, further comprising discharging the energy storage device responsive to the regulation signal, thereby transmitting power to the electrical power distribution system.

12. The method of claim 1, wherein the energy storage device comprises a battery in an electric vehicle or a plug-in hybrid electric vehicle.

13. The method of claim 1, wherein the energy storage device comprises a stationary power source, pumped water storage, a flywheel, or a battery-supplemented photovoltaic power system.

14. The method of claim 1, wherein the first data includes voltage data representing an operating voltage of the electrical power distribution system.

15. The method of claim 1, further comprising clamping the discharging rate below a first selected charging rate or above a second selected charging rate, wherein the first and second selected charging rates are selected in response to a pre-determined or user-selected completion time for charging the energy storage device.

16. One or more non-transitory computer-readable storage media storing computer-readable instructions that when executed by a computer cause the computer to perform a method, the method comprising:

selecting an upper charge rate limit and a lower charge rate limit based on an actual charging rate of an energy storage device coupled to discharge electrical power to an electrical power distribution system via a bi-directional charging system;

selecting a discharging rate from a range of two or more discharging rates between the selected upper charge rate limit and the selected lower charge rate limit based on first data representing one or more electrical characteristics of an alternating current (AC) electrical power distribution system; and

generating a regulation signal for causing the bi-directional charging system to discharge the energy storage device, the regulation signal being based at least in part on the selected discharging rate.

17. The computer-readable storage media of claim 16, wherein the first data includes frequency data representing an instantaneous frequency of the electrical power distribution system.

18. The computer-readable storage media of claim 17, wherein the selecting comprises computing a difference between the instantaneous frequency and an average of previously received instantaneous frequency data.

19. The computer-readable storage media of claim 16, wherein the selecting comprises:

computing an average of previously received data representing one or more electrical characteristics;

computing a difference between the received data and the average;

if the difference indicates that the electrical power distribution system has excess energy, selecting a charging rate to charge the energy storage device; and

if the difference indicates that the electrical power distribution system has a shortage of energy, selecting the discharging rate to discharge the energy storage device.

20. The computer-readable storage media of claim 16, wherein the method further comprises generating a regulation signal for causing the bi-directional charging system to charge the energy storage device, the regulation signal being based at least in part on the selected discharging rate.

21. The computer-readable storage media of claim 16, wherein the selecting is based, at least in part, on a state-of-charge of the energy storage device.

22. The computer-readable storage media of claim 16, wherein the selecting is based, at least in part, on a desired final charging time for the energy storage device.

23. The computer-readable storage media of claim 16, wherein the method further comprises receiving an upper frequency parameter defining an over-frequency event of the electrical power distribution system, a lower frequency parameter defining an under-frequency event of the electrical power distribution system, and wherein the selecting is based at least in part on one or more of the upper frequency parameter and the lower frequency parameter.

24. The computer-readable storage media of claim 16, wherein the method further comprises discharging the energy storage device responsive to the regulation signal, thereby transmitting power to the electrical power distribution system.

25. The computer-readable storage media of claim 16, wherein the method further comprises clamping the discharging rate above a selected discharging rate, wherein the selected charging rate is selected in response to a pre-determined or user-selected completion time for charging the energy storage device.

26. The computer-readable storage media of claim 16, wherein the method further comprises:

measuring the actual charging rate of the energy storage device;

selecting a new upper charge rate limit and/or a new lower charge rate limit based on the measured actual charging rate; and

performing the selecting the discharging rate and the generating the regulation signal based on the new upper charge rate limit and/or the new lower charge rate limit.

27. A system, comprising:

one or more processing units;

one or more non-transitory computer-readable storage media storing computer-readable instructions that when executed by the processing units determine a varying discharging rate for a bi-directional charger using;

a logic module operable to determine the discharging rate for the bi-directional charger as a function of an instantaneous frequency, an average frequency, and either a maximum or a minimum frequency of an electrical power distribution system and on second data representing a status of an energy storage device;

a data output module operable to send charger output rate data representing the determined discharging rate; and

wherein the processing units are configured to transmit the determined charging rate to the bi-directional charger with the data output module.