DC to DC power converters and methods of controlling the same

1. A power generation system comprising:

a plurality of power generation units each configured to output DC power, wherein the power generation units comprise photovoltaic units;

a plurality of DC to DC partial power converters each coupled to a respective power generation unit and each comprising an input section and an output section, wherein the output section is coupled in series with the respective power generation unit, wherein each DC to DC partial power converter is configured to process a first portion of the DC power output of the respective power generation unit and to provide an unprocessed second portion of the DC power output of the respective power generation unit to the output section;

at least one combiner for combining the DC power output from the output sections of the DC to DC partial power converters and providing the combined DC power to a main system DC link; and

at least one DC to AC inverter coupled to the main system DC link and configured to control a voltage level of the power output from the DC to DC partial power converters on the main system DC link.

2. A system in accordance with claim 1 , wherein, for each of the DC to DC partial power converters, the input section and the output section are directly coupled.

3. A system in accordance with claim 1 , wherein each of the DC to DC partial power converters comprises at least one transformer, wherein the input section comprises a primary winding of the at least one transformer and the output section comprises a secondary winding of the at least one transformer, and wherein the primary winding receives the first portion of the DC power output of the power generation unit and induces a voltage across the secondary winding that is combined with the second unprocessed portion of the DC power output of the power generation unit and provided as the power output from the DC to DC partial power converter.

4. A system in accordance with claim 1 , wherein each of the DC to DC partial power converters is configured to control a DC link current to extract a maximum power from the respective power generation unit.

5. A system in accordance with claim 4 , wherein each of the DC to DC partial power converters is configured to maximize the current output from the DC to DC partial power converter to maximize the output power of the respective power generation unit.

6. The power generation system in accordance with claim 1 , wherein each of the DC to DC partial power converters comprises at least one switch, and wherein each of the DC to DC partial power converters is configured to maintain the at least one semiconductor switch in a first position when a voltage output of the at least one power generation unit exceeds a predefined level.

7. The power generation system in accordance with claim 1 , wherein each of the DC to DC partial power converters comprises at least one switch, and wherein each of the DC to DC partial power converters is configured to operate the at least one semiconductor switch to limit a fault current within the power generation system.

8. The power generation system in accordance with claim 1 , wherein each of the DC to DC partial power converters comprises at least one diode for providing isolation under fault conditions.

9. The power generation system in accordance with claim 1 , wherein each of the DC to DC partial power converters comprises at least one switch comprising silicon carbide, gallium nitride, or a combination thereof.

10. A direct current (DC) to DC partial power converter comprising:

an input section configured to receive a first portion of a DC power output of a photovoltaic power generation unit, the input section comprising an input capacitor, a switch, and an inductor; and

an output section configured to output a DC power that includes the first processed portion and a second unprocessed portion of the DC power output of the power generation unit to a DC link, the output section comprising an output capacitor and an output diode,

wherein the output capacitor and the output diode are each connected to a positive node of a DC link, the input capacitor and the switch are each coupled to a negative node of the DC link, and the inductor is connected at one end between the input and output capacitors and at another end between the output diode and the switch.

11. A converter in accordance with claim 10 , further comprising a controller configured to control a DC link current output of the output section to extract a maximum power from the power generation unit.

12. A converter in accordance with claim 10 , wherein a rated power of the DC to DC partial power converter is less than the DC power output applied to the DC link.

13. The converter in accordance with claim 1 , wherein the switch comprises silicon carbide or gallium nitride.

14. A method for controlling operation of a power generation system including at least one power generation unit, at least one partial power converter comprising at least one semiconductor switch, and a DC to AC inverter, the method comprising:

configuring the partial power converter to determine a level of current flowing through the at least one semiconductor switch;

configuring the partial power converter to maximize the level of current flowing through the at least one semiconductor switch to maximize a power output of the at least one power generation unit; and

configuring the DC to AC inverter to control a voltage level of the power output of the partial power converter.

15. A method in accordance with claim 14 , further comprising configuring the controller to maintain the at least one semiconductor switch in a first position when a voltage output of the at least one power generation unit exceeds a predefined level.

16. A method in accordance with claim 14 , further comprising configuring the controller to operate the at least one semiconductor switch to limit a fault current within the power generation system.

17. A method in accordance with claim 14 , further comprising configuring the partial power converter to deliver a portion of the total power delivered to a DC link.