Techniques for controlling energy generation and storage systems

• US 9,270,118 B2
• Filed: 07/19/2012
• Issued: 02/23/2016
• Est. Priority Date: 07/19/2012
• Status: Active Grant

• Current Assignee: SolarCity Corporation (Tesla Inc.)
• Original Assignee: SolarCity Corporation (Tesla Inc.)
• Inventors: Carlson, Eric Daniel, Varadarajan, Karthikeyan
• Primary Examiner(s): Everett, Christopher E
• Application Number:
  US13/553,603
• Publication Number:
  US 20140025220A1
• Time in Patent Office: 1,314 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B60L 53/68 Off-site monitoring or control, e.g. remote control
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: H01L 31/02021 for solar cells electrical connection means, e.g. junction boxes, specially adapted for structural association with photovoltaic modules H02S40/34
• CPC Class Codes: H02J 13/00004 characterised by the power network being locally controlled
• 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 2310/14 The load or loads being home appliances
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: H02J 3/28 Arrangements for balancing of the load in a network by storage of energy
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• 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 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• 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 90/12 Electric charging stations
• 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 10/123 : the energy generation units being or involving renewable energy sources
• 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 20/12 : Energy storage units, uninterruptible power supply [UPS] systems or standby or emergency generators, e.g. in the last power distribution stages
• CPC Class Codes: Y04S 20/222 : Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/242 : Home appliances
• CPC Class Codes: Y04S 30/12 : Remote or cooperative charging
• 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
• CPC Class Codes: Y10T 29/49117 : Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/53013 : Computer input

Abstract

Techniques for controlling energy generation and/or storage systems. In one embodiment, a method is provided that can comprise receiving from a control server a plurality of schedules for controlling the charging and discharging of an energy storage device, where each schedule corresponds to a function that takes as input one or more input parameters and returns as output an output parameter corresponding to a power level for the energy storage device. The method can further comprise determining relative priorities for the plurality of schedules and controlling charging/discharging of the energy storage device based on the plurality of schedules and their relative priorities.

Claims

1. A method comprising:

receiving, by a site gateway from a control server, a plurality of schedules for controlling charging and discharging of an energy storage device, each schedule in the plurality of schedules corresponding to a function that takes as input one or more input parameters and returns as output an output parameter corresponding to a power level for the energy storage device;

determining, by the site gateway, relative priorities for the plurality of schedules;

determining, by the site gateway, conflicting schedules within the plurality of schedules, wherein the output parameters of each of the conflicting schedules correspond to different desired output power levels of the energy storage device; and

selecting, by the site gateway, one of the conflicting schedules based on their relative priorities to control charging and discharging of the energy storage device.

2. The method of claim 1 wherein determining the relative priorities for the plurality of schedules comprises receiving priority information from the control server.

3. The method of claim 2 wherein the priority information includes, for each schedule in the plurality of schedules, a schedule identifier, a priority value, and a priority operator.

4. The method of claim 3 wherein the priority operator is selected from a group consisting of max, min, and target,

wherein the max priority operator indicates that the function corresponding to the schedule defines a maximum permissible upper bound on the power level for the energy storage device,

wherein the min priority operator indicates that the function corresponding to the schedule defines a minimum permissible lower bound on the power level for the energy storage device, and

wherein the target priority operator indicates that the function corresponding to the schedule defines an exact power level for the energy storage device.

5. The method of claim 4 wherein controlling charging and discharging of the energy storage device based on the plurality of schedules and their relative priorities comprises:

initializing a variable Pbatt; and

for each schedule in the plurality of schedules, ordered from lowest priority to highest priority;

if the priority operator for the schedule is max;

evaluating the function corresponding to the schedule and setting a variable Pmax to the function output; and

setting Pbatt to the lesser of Pmax and Pbatt;

else if the priority operator for the schedule is min;

evaluating the function corresponding to the schedule and setting a variable Pmin to the function output; and

setting Pbatt to the greater of Pmin and Pbatt;

else if the priority operator for the schedule is target;

evaluating the function corresponding to the schedule and setting Pbatt to the function output.

6. The method of claim 5 further comprising charging or discharging the energy storage device based on Pbatt.

7. The method of claim 1 wherein at least one schedule in the plurality of schedules corresponds to a function that takes as input two or more input parameters.

8. The method of claim 7 wherein the two or more input parameters include time of day, state of charge of the energy storage device, or site power consumption.

9. The method of claim 7 wherein the function is expressed as an N-dimensional array, each value in the array representing a power level for the energy storage device, each dimension of the array representing an input parameter of the function.

10. The method of claim 1 wherein each schedule in the plurality of schedules is based on one or more use cases for optimizing economic value of the energy storage device, wherein the energy storage device is part of an energy generation system, and wherein the relative priorities are determined according to boundaries of output power levels of the energy storage device of the energy storage system.

11. The method of claim 10 wherein the one or more use cases include a use case for keeping a predefined percentage of energy storage device energy reserved for critical loads, a use case for keeping peak power demand below a predefined threshold, and a use case for buying and selling energy storage device energy at predefined times of day.

12. The method of claim 10 wherein at least one schedule the plurality of schedules is defined by a utility company configured to provide power for charging the energy storage device.

13. The method of claim 1 wherein each schedule in the plurality of schedules is associated with a start time indicating a time at which the schedule should take effect for controlling charging and discharging of the energy storage device.

14. The method of claim 13 wherein the start time is dependent on a time at which the site gateway last made contact with the control server.

15. The method of claim 13 wherein each schedule in the plurality of schedules is further associated with an end time indicating a time at which the schedule should no longer take effect for controlling charging and discharging of the energy storage device.

16. The method of claim 15 wherein the end time is dependent on the time at which the site gateway last made contact with the control server.

17. The method of claim 1 wherein the energy storage device is a battery, and wherein the site gateway is configured to control the energy storage device by communicating with a battery inverter/charger.

18. The method of claim 17 wherein the site gateway is further configured to communicate with an energy inverter coupled with an energy generation source and with a utility meter coupled with a utility power grid, and wherein the energy storage device is capable of being charged using energy received from the energy generation source or from the utility power grid.

19. A system comprising:

a processor configured to;

receive, from a control server, a plurality of schedules for controlling charging and discharging of an energy storage device, each schedule in the plurality of schedules corresponding to a function that takes as input one or more input parameters and returns as output an output parameter corresponding to a power level for the energy storage device;

determine relative priorities for the plurality of schedules;

determine, by the site gateway, conflicting schedules within the plurality of schedules, wherein the output parameters of each of the conflicting schedules correspond to different desired output power levels of the energy storage device; and

select, by the site gateway, one of the conflicting schedules based on their relative priorities to control charging and discharging of the energy storage device.

20. The non-transitory computer-readable storage medium having stored thereon program code executable by a computer system, the program code comprising:

code that causes the computer system to receive, from a control server, a plurality of schedules for controlling charging and discharging of an energy storage device, each schedule in the plurality of schedules corresponding to a function that takes as input one or more input parameters and returns as output an output parameter corresponding to a power level for the energy storage device;

code that causes the computer system to determine relative priorities for the plurality of schedules;

code that causes the computer system to determine, by the site gateway, conflicting schedules within the plurality of schedules, wherein the output parameters of each of the conflicting schedules correspond to different desired output power levels of the energy storage device; and

code that causes the computer system to select, by the site gateway, one of the conflicting schedules based on their relative priorities to control charging and discharging of the energy storage device.