Circuit for interconnected direct current power sources
Controlling a power converter circuit for a direct current (DC) power source is disclosed. The power converter may be operative to convert input power received from the DC power source to an output power and to perform maximum power point tracking of the power source. The power converter is adapted to provide the output power to a load that also performs maximum power point tracking.
1. An apparatus comprising:
a power converter having input terminals and output terminals and being operative to convert input power received from a direct current power source at the input terminals to output power at the output terminals; and
a control circuit configured to:
control the power converter to draw the input power according to a maximum power point tracking algorithm; and
while drawing the input power according to the maximum power point tracking algorithm, vary the output power to present, for a first time period, a maximum output power point and to present, for a second time period, a reduced output power point.
2. The apparatus of claim 1 , wherein the control circuit is configured to decrease, while maintaining the input power at a maximum input power point, the output power from the maximum output power point to the reduced output power point.
3. The apparatus of claim 1 , wherein the control circuit is configured to vary the output power to present the reduced output power point by adjusting conversion efficiency of the power converter.
4. The apparatus of claim 1 , wherein the control circuit is configured to decrease, based on determining that a voltage value or a current value of the output terminals is being outside of a predetermined range, the output power to the reduced output power point.
5. The apparatus of claim 4 , wherein the control circuit is configured to increase the output power from the reduced output power point to a higher output power point,
wherein the voltage value or the current value of the output terminals is within the predetermined range after the increase of the output power.
6. The apparatus of claim 4 , wherein the control circuit is configured to lock onto an output power point lower than the maximum output power point to mantain the voltage value or the current value of the output terminals within the predetermined range.
7. The apparatus of claim 1 , wherein a rate of varying the output power is slower than a rate of tracking of a maximum power point tracking circuit that is configured to track the output power.
8. The apparatus of claim 1 , wherein the direct current power source comprises a photovoltaic solar panel or a photovoltaic solar cell, and
wherein the control circuit is configured to control the power converter to draw, according to the maximum power point tracking algorithm, the input power at a maximum input power point, and
wherein the maximum input power point varies according a changing condition associated with the photovoltaic solar panel or the photovoltaic solar cell.
9. A system comprising:
a plurality of power converters; and
an inverter configured to receive combined power output from the plurality of power converters, and to track a variation of the combined power,
wherein at least one of the plurality of power converters comprises:
input terminals;
output terminals;
a power converting circuit configured to convert input power received from a direct current power source at the input terminals to output power at the output terminals; and
a control circuit configured to:
control the at least one of the plurality of power converters to draw the input power according to a maximum power point tracking algorithm and
while drawing the input power according to the maximum power point tracking algorithm, vary the output power to present, for a first time period, a maximum output power point and to present, for a second time period, a reduced output power point.
10. The system of claim 9 , wherein the control circuit is configured to decrease, while maintaining the input power at a maximum input power point, the output power from the maximum output power point to the reduced output power point, and
wherein the reduced output power point is associated with a maximum combined power point for the inverter.
11. The system of claim 9 , wherein the control circuit is configured to vary the output power to present the reduced output power point by adjusting conversion efficiency of the power converting circuit.
12. The system of claim 9 , wherein the control circuit is configured to decrease, based on determining that a voltage value or a current value of the output terminals is being outside of a predetermined range, the output power to the reduced output power point.
13. The system of claim 12 , wherein the control circuit is configured to increase the output power from the reduced output power point to a higher output power point,
wherein the voltage value or the current value of the output terminals is within the predetermined range after the increase of the output power.
14. The system of claim 12 , wherein the control circuit is configured to lock onto an output power point lower than the maximum output power point to maintain the voltage value or the current value of the output terminals within the predetermined range.
15. The system of claim 9 , wherein a rate of varying the output power is slower than a rate of tracking of a maximum power point tracking circuit, of the inverter, that is configured to track the output power.
16. The system of claim 9 , wherein the direct current power source comprises a photovoltaic solar panel or a photovoltaic solar cell, and
wherein the control circuit is configured to control the at least one of the plurality of power converters to draw, according to the maximum power point tracking algorithm, the input power at a maximum input power point, and
wherein the maximum input power point varies according a changing condition associated with the photovoltaic solar panel or the photovoltaic solar cell.
17. A method comprising:
converting input power, received from a direct current power source, at input terminals of a power converter to output power at output terminals of the power converter;
drawing the input power according to a maximum power point tracking algorithm; and
varying, by a control circuit and while drawing the input power according to the maximum power point tracking algorithm, the output power to present, for a first time period, a maximum output power point and to present, for a second time period, a reduced output power point.
18. The method of claim 17 , wherein varying the output power comprises decreasing, while maintaining the input power at a maximum input power point, the output power from the maximum output power point to the reduced output power point.
19. The method of claim 17 , wherein varying the output power comprises varying the output power to present the reduced output power point by adjusting conversion efficiency of the power converter.
20. The method of claim 17 , wherein varying the output power comprises decreasing, based on determining that a voltage value or a current value of the output terminals is being outside of a predetermined range, the output power to the reduced output power point.
21. The method of claim 20 , wherein varying the output power further comprises increasing the output power from the reduced output power point to a higher output power point,
wherein the voltage value or the current value of the output terminals is within the predetermined range after increasing the output power to the higher output power point.
22. The method of claim 20 , wherein varying the output power further comprises locking onto an output power point lower than the maximum output power point to maintain the voltage value or the current value of the output terminals within the predetermined range.
23. The method of claim 17 , wherein a rate of varying the output power is slower than a rate of tracking of a maximum power point tracking circuit that is configured to track the output power.
24. The method of claim 17 , wherein the direct current power source comprises a photovoltaic solar panel or a photovoltaic solar cell,
wherein drawing the input power comprises drawing, according to the maximum power point tracking algorithm, the input power at a maximum input power point, and
wherein the maximum input power point varies according to a changing condition associated with the photovoltaic solar panel or the photovoltaic solar cell.