DEVICE, SYSTEM, AND METHOD FOR MANAGING AN APPLICATION OF POWER FROM PHOTOVOLTAIC ARRAYS

• US 20100132758A1
• Filed: 12/02/2008
• Published: 06/03/2010
• Est. Priority Date: 12/02/2008
• Status: Active Grant

• Current Assignee: Advanced Energy Industries Incorporated
• Original Assignee: Advanced Energy Industries Incorporated
• Inventors: Gilmore, Jack Arthur
• Granted Patent: US 8,362,644 B2
• Time in Patent Office: Days
• US Class Current: 136/244
• 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: H02S 50/10 Testing of PV devices, e.g. of PV modules or single PV cells testing of semiconductor devices during manufacturing H01L22/00
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A system, method, and apparatus for managing an application of power from photovoltaic arrays to power conversion components. The method may include arranging a first array and a second array in series, coupling a positive terminal of a first array to the power conversion component, coupling a negative terminal of a second array to the power conversion component, and modulating an amount of current flowing between a negative terminal of the first array and a positive terminal of the second array so as to ramp up a level of current flowing through the arrays as the arrays are brought online with the power conversion component. A voltage of any terminal on either of the arrays may be limited so that the voltage on any of the terminals does not reach a restricted level.

Claims

1. A photovoltaic system comprising:

a first photovoltaic array configured to generate a direct current (DC) power, wherein at least a portion of the first photovoltaic array is disposed above ground potential and includes a positive terminal and a negative terminal;

a second photovoltaic array configured to generate a direct current (DC) power, wherein at least a portion of the second photovoltaic array is disposed below ground potential and includes a negative terminal and a positive terminal;

a power conversion component coupled to both, the positive terminal of the first photovoltaic array and the negative terminal of the second photovoltaic array, the power conversion component adapted to convert a voltage between the positive terminal of the first photovoltaic array and the negative terminal of the second photovoltaic array from one form to another form; and

an array coupler configured to electrically couple the negative terminal of the first array and the positive terminal of second array and to modulate an amount of current flowing through the first and second photovoltaic arrays.

2. The system of claim 1, including two resistor sets, each resistor set disposed across each array, each resistor set including two resistors, and a node between each of the two resistors is coupled to ground.

3. The system of claim 2, wherein the resistors are sized so that the maximum voltage with respect to ground of either array is below 600V.

4. The system of claim 2, wherein the positive terminal of second array is about +200 Volts, the negative terminal of the second array is about −

500 Volts, the negative terminal of the first array is about −

200 Volts and the positive terminal of the first array is about +500 Volts.

5. The system of claim 1, wherein the array coupler is housed within the power conversion component.

6. The system of claim 1, wherein the array coupler is located externally from a housing of the power conversion component.

7. The system of claim 1, wherein the power conversion component includes a component selected from the group consisting of an inverter and a DC to DC power converter.

8. The system of claim 1, wherein the array coupler includes

a switching component and an array contactor, the switching component configured, when bringing the arrays online with the power converter, to close for successively longer times so as to increase the amount of current flowing through the first and second photovoltaic arrays, the array contactor configured to close so as to electrically couple the negative terminal of the first array to the positive terminal of the second array after the arrays are online with the power converter.

9. The system of claim 5, wherein the switching component includes an insulated gate bipolar transistor.

10. A method for coupling photovoltaic arrays with a power conversion component comprising:

arranging a first array and a second array in series;

coupling a positive terminal of a first array to the power conversion component;

coupling a negative terminal of a second array to the power conversion component;

modulating an amount of current flowing between a negative terminal of the first array and a positive terminal of the second array so as to ramp up a level of current flowing through the arrays as the arrays are brought online with the power conversion component; and

limiting a voltage of any terminal on either of the arrays so that the voltage on any of the terminals does not reach a restricted level.

11. The method of claim 10, wherein modulating includes decreasing an effective resistance of the array coupler.

12. The method of claim 11, wherein the modulating includes closing, for successively longer times, a switch so as to increase the amount of current flowing through the first and second photovoltaic arrays.

13. The method of claim 10, wherein a combined open circuit voltage across the arrays exceeds 1300 Volts and wherein, after the arrays are brought online with the power conversion component, the voltage across the arrays is less than 1000 Volts.

14. The method of claim 10 wherein the restricted level of voltage is 600 Volts.

15. The method of claim 10, wherein a combined open circuit voltage across the arrays exceeds a design-voltage of the inverter.

16. An apparatus for coupling photovoltaic arrays comprising:

a first input adapted to couple to a negative terminal of a first photovoltaic array;

a second input adapted to couple to a positive terminal of a second photovoltaic array;

a contactor configured to switchably couple the negative terminal of the first photovoltaic array to the positive terminal of the second photovoltaic array so as to place the first and second photovoltaic arrays in series, the contactor being controllable by an electric control signal; and

a current modulator configured to modulate an amount of current flowing through the first and second photovoltaic arrays.

17. The apparatus of claim 16 including:

a control portion configured to;

activate the current modulator; and

close, after the current that is flowing through the arrays reaches a threshold level, the contactor.

18. The apparatus of claim 17 including a control input adapted to couple the control portion to a remote controller so as to enable the controller to be controlled by the remote controller.

19. The apparatus of claim 17, including at least one feedback input coupled to the control portion, the at least one feedback input being configured to provide feedback indicative of at least one of the voltage applied by the positive terminal of the first array and the negative terminal of the second array so as to enable the control portion to modulate current through the current modulator to keep the voltage of either of the terminals relative to ground less than 600 volts.

20. The apparatus of claim 19, wherein the controller, responsive to the feedback from the at least one feedback line, is configured to control the current flowing through the current modulator so that the voltage applied to each rail is a desirable voltage.