SYSTEMS AND METHODS FOR MODULAR POWER CONVERSION UNITS IN POWER SUPPLY SYSTEMS

1 . A power supply system comprising:

a direct current (DC) bus;

a first alternating current (AC) bus;

at least one modular power conversion unit, said at least one modular power conversion unit comprising:

a high-frequency direct current to alternating current (DC/AC) transformer electrically coupled between said DC bus and said first AC bus; and

a direct current to direct current (DC/DC) converter electrically coupled to said high-frequency DC/AC transformer and said DC bus; and

a battery string, wherein said DC/DC converter is electrically coupled between said DC bus and said battery string.

2 . A power supply system in accordance with claim 1 , wherein said first AC bus is electrically coupled to a distribution grid.

3 . A power supply system in accordance with claim 1 , wherein said high-frequency DC/AC transformer is configured to convert a first voltage on said DC bus to a second voltage on said first AC bus, and wherein the first voltage is lower than the second voltage.

4 . A power supply system in accordance with claim 1 , wherein said at least one modular power conversion unit further comprises a direct current to alternating current (DC/AC) converter electrically coupled to said high-frequency DC/AC transformer, said DC/DC converter, and said DC bus.

5 . A power supply system in accordance with claim 4 , further comprising a second AC bus, wherein said DC/AC converter is electrically coupled between said DC bus and said second AC bus.

6 . A power supply system in accordance with claim 5 , wherein said DC bus has a voltage of approximately 1500 Volts (V) or lower, wherein said first AC bus has a voltage in a range from approximately 4160 V to approximately 34.5 kiloVolts (kV), and wherein said second AC bus has a voltage in a range from approximately 240 V to approximately 1000 V.

7 . A power supply system in accordance with claim 5 , wherein said second AC bus is electrically coupled to a load grid.

8 . A power supply system in accordance with claim 1 , wherein said at least one modular power conversion unit comprises a plurality of modular power conversion units electrically coupled in parallel with one another.

9 . A power supply system in accordance with claim 1 , wherein said DC bus is electrically coupled to a photovoltaic system.

10 . A power supply system in accordance with claim 1 , wherein said DC bus is electrically coupled to an electric vehicle charger.

11 . A power supply system in accordance with claim 1 , wherein said at least one modular power conversion unit is configured to prevent backfeeding.

12 . A modular power conversion unit, comprising:

a high-frequency direct current to alternating current (DC/AC) transformer, wherein said high-frequency DC/AC transformer comprises a direct current (DC) port configured to be electrically coupled to a direct current (DC) bus and an alternating current (AC) port configured to be electrically coupled to a first AC bus; and

a direct current to direct current (DC/DC) converter, wherein said DC/DC converter comprises a first converter port and a second converter port, wherein said first converter port is electrically coupled to said DC port of said high-frequency DC/AC transformer, and wherein said second converter port is configured to be electrically coupled to a battery string.

13 . A modular power conversion unit in accordance with claim 12 , wherein said high-frequency DC/AC transformer is configured to convert a first voltage on the DC bus to a second voltage on the first AC bus, and wherein the first voltage is lower than the second voltage.

14 . A modular power conversion unit in accordance with claim 12 , further comprising a direct current to alternating current (DC/AC) converter, wherein said DC/AC converter further comprises a DC port and an AC port, and wherein said DC port of said DC/AC converter is electrically coupled to said first converter port of said DC/DC converter and said DC port of said high-frequency DC/AC transformer.

15 . A modular power conversion unit in accordance with claim 14 , wherein said DC port of said DC/AC converter is configured to be electrically coupled to the DC bus, and wherein said AC port of said DC/AC converter is configured to be electrically coupled to a second AC bus.

16 . A modular power conversion unit in accordance with claim 12 , wherein said modular power conversion unit is configured to prevent backfeeding of electrical power.

17 . A modular power conversion unit in accordance with claim 12 , wherein said second converter port of said DC/DC converter is configured to be electrically coupled to a battery string including at least one energy cell.

18 . A method of assembling a power supply system, said method comprising:

forming at least one modular power conversion unit by electrically coupling a high-frequency direct current to alternating current (DC/AC) transformer to a direct current to direct current (DC/DC) converter;

electrically coupling the at least one modular power conversion unit to a direct current (DC) bus;

electrically coupling the at least one modular power conversion unit to a first AC bus such that the high-frequency DC/AC transformer is electrically coupled between the DC bus and the first AC bus; and

electrically coupling the at least one modular power conversion unit to a battery string such that the DC/DC converter is electrically coupled between the DC bus and the battery string.

19 . A method in accordance with claim 18 , wherein forming at least one modular power conversion unit further comprises electrically coupling a DC/AC converter to the DC/DC converter and the high-frequency DC/AC transformer.

20 . A method in accordance with claim 19 , said method further comprising electrically coupling the at least one modular power conversion unit to a second AC bus such that the DC/AC converter is electrically coupled between the DC bus and the second AC bus.