PHOTOVOLTAIC ENERGY SYSTEM WITH VALUE FUNCTION OPTIMIZATION

• US 20170104337A1
• Filed: 08/25/2016
• Published: 04/13/2017
• Est. Priority Date: 10/08/2015
• Status: Active Grant

• Current Assignee: Con Edison Battery Storage, LLC
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Drees, Kirk H.
• Granted Patent: US 10,389,136 B2
• Time in Patent Office: Days
• CPC Class Codes: G06Q 30/0283 Price estimation or determination
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/40 Synchronising a generator for connection to a network or to another generator
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: H02S 40/32 comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules
• CPC Class Codes: H02S 40/38 Energy storage means, e.g. batteries, structurally associated with PV modules
• CPC Class Codes: H02S 50/00 Monitoring or testing of PV systems, e.g. load balancing or fault identification
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 70/30 Systems combining energy storage with energy generation of non-fossil origin
• CPC Class Codes: Y04S 50/14 Marketing, i.e. market research and analysis, surveying, promotions, advertising, buyer profiling, customer management or rewards

Abstract

A photovoltaic energy system includes a photovoltaic field configured to convert solar energy into electrical energy, a power inverter configured to control an electric power output of the photovoltaic field, and a controller. The controller can determine optimal power setpoints for the power inverter by optimizing a value function that includes a penalty cost for failing to comply with a ramp rate limit and photovoltaic revenue.

Claims

1. A photovoltaic energy system comprising:

a photovoltaic field configured to convert solar energy into electrical energy;

a power inverter configured to control an electric power output of the photovoltaic field; and

a controller configured to determine optimal power setpoints for the power inverter by optimizing a value function that includes a penalty cost for failing to comply with a ramp rate limit and photovoltaic revenue as a function of the power setpoints.

2. The photovoltaic energy system of claim 1, wherein the power inverter is configured to control the power output of the photovoltaic field to an energy grid.

3. The photovoltaic energy system of claim 1, wherein the power inverter is configured to convert a direct current (DC) output of the photovoltaic field into an alternating current (AC) output and provide the AC output to an energy grid, the AC output defining an electric power output of the photovoltaic energy system.

4. The photovoltaic energy system of claim 1, wherein the controller is configured to determine a set of optimal power setpoints for the power inverter at each of a plurality of time steps within a prediction window.

5. The photovoltaic energy system of claim 1, wherein the controller is configured to estimate the photovoltaic revenue as a function of an electric power output to an energy grid resulting from the power setpoints and a price of the electric power output to the energy grid.

6. The photovoltaic energy system of claim 1, wherein the controller is configured to estimate the penalty cost of failing to comply with the ramp rate limit as a function of a number of noncompliance events and an amount by which an actual rate of change of the electric power output exceeds the ramp rate limit.

7. The photovoltaic energy system of claim 1, wherein the controller is configured to optimize the value function over a prediction window comprising a plurality of time steps;

wherein the value function is a summation of the photovoltaic revenue and the penalty cost at each of the plurality of time steps.

8. A photovoltaic energy system comprising:

a photovoltaic field configured to convert solar energy into electrical energy;

a first power inverter configured to control an electric power output of the photovoltaic field;

a battery;

a second power inverter configured to control an electric power output of the battery; and

a controller configured to determine optimal power setpoints for the first power inverter and the second power inverter by optimizing a value function that includes at least one of a cost of battery capacity loss and battery operating cost as a function of the power setpoints.

9. The photovoltaic energy system of claim 8, wherein the first power inverter is configured to control the electric power output of the photovoltaic field to an energy grid and the second power inverter is configured to control the electric power output of the battery to the energy grid.

10. The photovoltaic energy system of claim 8, wherein the first and second power inverters are configured to convert a direct current (DC) output of the photovoltaic field and the battery into an alternating current (AC) output and provide the AC outputs to an energy grid, the AC outputs defining a total electric power output of the photovoltaic energy system.

11. The photovoltaic energy system of claim 8, wherein the battery is configured to store at least a portion of the electrical energy generated by the photovoltaic field;

wherein the controller is configured to adjust a total electric power output of the photovoltaic energy system using electrical energy from the battery to supplement the electric power output of the photovoltaic field.

12. The photovoltaic energy system of claim 8, wherein the controller is configured to estimate the battery operating cost as a function of at least one of:

cost of charging the battery;

cost of discharging the battery; and

heat generation from the battery.

13. The photovoltaic energy system of claim 8, wherein the value function further comprises at least one of:

estimated revenue from an electric power output of the photovoltaic energy system to an energy grid;

estimated cost of failing to comply with a ramp rate limit; and

electric power losses within at least one of the first power inverter and the second power inverter.

14. The photovoltaic energy system of claim 8, wherein the controller is configured to determine a set of optimal power setpoints for the first power inverter and the second power inverter at each of a plurality of time steps within a prediction window.

15. A renewable energy system comprising:

a renewable energy field configured to convert a renewable energy source into electrical energy;

a first power inverter configured to control a power output of the renewable energy field;

a battery;

a second power inverter configured to control a power output of the battery; and

a controller configured to determine optimal power setpoints for the first power inverter and the second power inverter by optimizing a value function that includes at least one of a cost of battery capacity loss and battery operating cost as a function of the power setpoints.

16. The renewable energy system of claim 15, wherein the renewable energy field comprises at least one of a photovoltaic field, a wind turbine field, a hydroelectric field, a tidal energy field, and a geothermal energy field.

17. The renewable energy system of claim 15, wherein the first power inverter is configured to control the electric power output of the renewable energy field to an energy grid and the second power inverter is configured to control the electric power output of the battery to the energy grid.

18. The renewable energy system of claim 15, wherein the battery is configured to store at least a portion of the electrical energy generated by the renewable energy field;

wherein the controller is configured to adjust a total electric power output of the renewable energy system using electrical energy from the battery to supplement the electric power output of the renewable energy field.

19. The renewable energy system of claim 15, wherein the controller is configured to estimate the battery operating cost as a function of at least one of:

cost of charging the battery;

cost of discharging the battery; and

heat generation from the battery.

20. The renewable energy system of claim 15, wherein the controller is configured to determine a set of optimal power setpoints for the first power inverter and the second power inverter at each of a plurality of time steps within a prediction window.