Method and system for providing maximum power point tracking in an energy generating system

• US 8,279,644 B2
• Filed: 06/23/2009
• Issued: 10/02/2012
• Est. Priority Date: 05/14/2008
• Status: Active Grant

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Zhang, Jianhui, Djabbari, Ali, Lisi, Gianpaolo
• Primary Examiner(s): Tran, Nguyen
• Application Number:
  US12/456,776
• Publication Number:
  US 20090284998A1
• Time in Patent Office: 1,197 Days
• Field of Search: 323/222, 323/223, 323/224, 323/265, 323/266, 323/282, 323/283, 323/284, 323/285, 363/37, 363/55, 363/56.03, 363/65, 363/95, 363/97, 363/98, 363/131
• US Class Current: 363/55
• CPC Class Codes: G05F 1/67 to the maximum power available from a generator, e.g. from solar cell
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence

Abstract

A method for providing a maximum power point tracking (MPPT) process for an energy generating device is provided. The method includes coupling a local converter to the energy generating device. A determination is made regarding whether the local converter is operating at or below a maximum acceptable temperature. A determination is made regarding whether at least one current associated with the local converter is acceptable. When the local converter is determined to be operating at or below the maximum acceptable temperature and when the at least one current associated with the local converter is determined to be acceptable, the MPPT process is enabled within the local converter.

Claims

1. A method for providing a maximum power point tracking (MPPT) process for an energy generating device, the method comprising:

determining whether a local converter coupled to the energy generating device is operating at or below a maximum acceptable temperature;

determining whether at least one current associated with the local converter is acceptable; and

when the local converter is determined to be operating at or below the maximum acceptable temperature and when the at least one current associated with the local converter is determined to be acceptable, enabling the MPPT process within the local converter.

2. The method of claim 1, further comprising:

when the local converter is determined to be operating above the maximum acceptable temperature, disabling the MPPT process within the local converter.

3. The method of claim 1, further comprising:

when the local converter is determined to be operating above the maximum acceptable temperature, setting a conversion ratio for the local converter to an initial conversion ratio.

4. The method of claim 1, further comprising:

when the at least one current associated with the local converter is determined to be unacceptable, disabling the MPPT process within the local converter.

5. The method of claim 4, wherein:

the at least one current associated with the local converter comprises an average output current for the local converter; and

the average output current is determined to be acceptable when the average output current is less than a maximum output current.

6. The method of claim 4, wherein the at least one current associated with the local converter comprises:

an output current for the local converter; and

an average input current for the local converter.

7. The method of claim 6, wherein:

when the MPPT process is disabled, the output current and the average input current are determined to be acceptable based on an upper minimum current threshold; and

when the MPPT process is enabled, the output current and the average input current are determined to be acceptable based on a lower minimum current threshold.

8. The method of claim 1, wherein the MPPT process comprises:

comparing an average output voltage to a maximum output voltage; and

when the average output voltage is greater than the maximum output voltage, decreasing a conversion ratio for the MPPT process while continuing to operate the local converter.

9. A method for providing a maximum power point tracking (MPPT) process for an energy generating device, the method comprising:

determining whether a local converter coupled to the energy generating device is operating at or below a maximum acceptable temperature;

determining whether an average output current for the local converter is less than a maximum output current;

determining whether an output current for the local converter is acceptable;

determining whether an average input current for the local converter is acceptable; and

enabling the MPPT process within the local converter when (i) the local converter is determined to be operating at or below the maximum acceptable temperature, (ii) the average output current is determined to be less than the maximum output current, (iii) the output current is determined to be acceptable, and (iv) the average input current is determined to be acceptable.

10. The method of claim 9, further comprising:

disabling the MPPT process within the local converter when (i) the local converter is determined to be operating above the maximum acceptable temperature, (ii) the average output current is determined to be greater than the maximum output current, (iii) the output current is determined to be unacceptable, or (iv) the average input current is determined to be unacceptable.

11. The method of claim 10, wherein:

when the MPPT process is disabled, the output current and the average input current are determined to be acceptable based on an upper minimum current threshold; and

when the MPPT process is enabled, the output current and the average input current are determined to be acceptable based on a lower minimum current threshold.

12. The method of claim 10, further comprising:

when the MPPT process is disabled, setting a conversion ratio for the local converter to an initial conversion ratio.

13. The method of claim 9, wherein the MPPT process comprises:

comparing an average output voltage to a maximum output voltage; and

when the average output voltage is greater than the maximum output voltage, decreasing a conversion ratio for the MPPT process while continuing to operate the local converter.

14. A system for providing maximum power point tracking (MPPT) for an energy generating device, the system comprising a local converter, the local converter comprising:

a power stage operable to receive a device voltage and a device current from the energy generating device and to generate an output voltage and an output current based on the device voltage and the device current; and

a local controller operable to provide MPPT for the power stage, the local controller comprising an MPPT module operable to;

determine whether the local converter is operating at or below a maximum acceptable temperature;

determine whether at least one current associated with the local converter is acceptable; and

enable an MPPT process within the local converter when the local converter is determined to be operating at or below the maximum acceptable temperature and when the at least one current associated with the local converter is determined to be acceptable.

15. The system of claim 14, wherein, when the local converter is determined to be operating above the maximum acceptable temperature, the MPPT module is further operable to disable the MPPT process within the local converter and to set a conversion ratio for the local converter to an initial conversion ratio.

16. The system of claim 14, wherein the MPPT module is operable to disable the MPPT process within the local converter when the at least one current associated with the local converter is determined to be unacceptable.

17. The system of claim 16, wherein:

the at least one current associated with the local converter comprises an average output current for the local converter; and

the MPPT module is operable to determine whether the at least one current associated with the local converter is acceptable by determining whether the average output current is less than a maximum output current.

18. The system of claim 17, wherein:

the at least one current associated with the local converter further comprises an output current for the local converter and an average input current for the local converter; and

the MPPT module is operable to determine whether the at least one current associated with the local converter is acceptable by;

determining whether the output current and the average input current are each greater than an upper minimum current threshold while the MPPT process is disabled; and

determining whether the output current and the average input current are each less than a lower minimum current threshold while the MPPT process is enabled.

19. The system of claim 14, wherein the MPPT process comprises:

comparing an average output voltage to a maximum output voltage; and

when the average output voltage is greater than the maximum output voltage, decreasing a conversion ratio for the MPPT process while continuing to operate the local converter.

20. The system of claim 14, wherein the energy generating device comprises a photovoltaic panel.