DUAL BOOST CONVERTER FOR UPS SYSTEM

• US 20130027126A1
• Filed: 07/28/2011
• Published: 01/31/2013
• Est. Priority Date: 07/28/2011
• Status: Active Grant

• Current Assignee: Schneider Electric IT Corporation (Schneider Electric SE)
• Original Assignee: American Power Conversion Corporation (Schneider Electric SE)
• Inventors: Jayaraman, Chandrasekaran, Prakash, Indra, Klikic, Damir
• Granted Patent: US 8,946,931 B2
• Time in Patent Office: Days
• US Class Current: 327/547
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02J 9/063 Common neutral, e.g. AC input neutral line connected to AC output neutral line and DC middle point
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load

Abstract

A power converter includes a power conversion circuit switchably coupled to a first power input and a second power input. The power conversion circuit is operable to generate positive and negative DC output voltages and is configured such that, in a backup mode of operation, the negative DC output voltage is generated using backup power through a first current path of the power conversion circuit that includes a first diode coupled between the second power input and a second DC bus, and, in a line mode of operation, the negative DC output voltage is generated using AC input power through a second current path of the power conversion circuit that bypasses the first diode and includes a second diode coupled between the first power input and the second DC bus.

Claims

1. A power converter, comprising:

a first power input to receive AC input power;

a second power input to receive backup power;

a first DC bus configured to provide a positive DC output voltage;

a second DC bus configured to provide a negative DC output voltage; and

a power conversion circuit switchably coupled to the first power input and the second power input, the power conversion circuit operable to generate the positive and negative DC output voltages and configured such that, in a backup mode of operation, the negative DC output voltage is generated using the backup power through a first current path of the power conversion circuit that includes a first diode coupled between the second power input and the second DC bus, and, in a line mode of operation, the negative DC output voltage is generated using the AC input power through a second current path of the power conversion circuit that bypasses the first diode and includes a second diode coupled between the first power input and the second DC bus.

2. The power converter of claim 1, wherein the first diode has a first cathode and a first anode, wherein the second diode has a second cathode, wherein the power conversion circuit includes an inductive element and a switch having a pole, a first contact and a second contact, the pole being coupled to the inductive element, the first contact being coupled to the first cathode of the first diode, the second contact being coupled to the first anode of the first diode and the second cathode of the second diode, the switch being configured to form a portion of the first circuit when the first contact is closed and a portion of the second circuit when the second contact is closed.

3. The power converter of claim 1, wherein the first diode is rated at approximately 600V, and wherein the second diode is rated at approximately 600V.

4. The power converter of claim 1, wherein the second diode includes a second anode coupled to the second DC bus.

5. The power converter of claim 1, wherein the second power input is coupled to a battery.

6. The power converter of claim 5, wherein the battery includes a negative terminal, and wherein the power converter further comprises a connection circuit configured to switchably couple the inductive element to one of the first power input and the negative terminal of the battery.

7. The power converter of claim 6, wherein the inductive element is coupled in series between the connection circuit and the second diode.

8. The power converter of claim 1, wherein the first diode is coupled in parallel with the second diode.

9. The power converter of claim 1, wherein the power conversion circuit is configured to be switchable between a first configuration and a second configuration, and wherein the first configuration of the power conversion circuit includes a boost converter circuit and the second configuration of the power conversion circuit includes a buck-boost converter circuit.

10. A method of providing power to a load, the method comprising:

detecting a loss of input power from a primary power source;

responsive to detecting the loss of the input power, generating, in a backup mode of operation, a negative DC output voltage using a backup power source through a first current path that includes a first diode coupled between the backup power source and a DC power bus;

detecting a presence of the input power from the primary power source; and

responsive to detecting the presence of the input power, generating, in a line mode of operation, the negative DC output voltage using the primary power source through a second current path that bypasses the first diode and includes a second diode coupled between the primary power source and the DC power bus.

11. The method of claim 10, further comprising coupling, in the backup mode of operation, a first cathode of the first diode to an inductive element using a switch to create a portion of the first current path including the first diode, the second diode, and the inductive element such that the first diode is coupled in series between the inductive element and the second diode.

12. The method of claim 11, further comprising decoupling, in the line mode of operation, the first cathode of the first diode from the inductive element using the switch and coupling a second cathode of the second diode to the inductive element using the switch to create a portion of the second current path that bypasses the first diode and includes the second diode and the inductive element.

13. The method of claim 12, wherein a first switching element is coupled in series between the first cathode of the first diode and a battery, wherein a second switching element is coupled to a first anode of the first diode and the second cathode of the second diode, and wherein the method further comprises energizing the first switching element a first amount of time subsequent to energizing the second switching element.

14. The method of claim 13, wherein the first amount of time is between approximately 0.5 microseconds and approximately 1.5 microseconds.

15. The method of claim 13, further comprising deenergizing the first switching element a second amount of time prior to deenergizing the second switching element.

16. The method of claim 15, wherein the second amount of time is between approximately 0.5 microseconds and approximately 1.5 microseconds.

17. A power converter, comprising:

a first power input to receive AC input power;

a second power input to receive backup power;

a power output to provide output power derived from at least one of the AC input power and the backup power;

a first diode and a second diode; and

means for providing a negative DC output voltage to the power output through the first diode and the second diode using the backup power in a backup mode of operation, and providing the negative DC output voltage to the power output through the second diode using the AC input power in a line mode of operation.

18. The power converter of claim 17, wherein the first diode and the second diode are each coupled between the second power input and the power output in the backup mode of operation, and wherein the second diode is coupled between the first power input and the power output in the line mode of operation.

19. The power converter of claim 17, wherein the first diode is bypassed in the line mode of operation.

20. The power converter of claim 17, wherein the power converter is configured to be switchable between a first configuration and a second configuration, and wherein the first configuration includes a boost converter circuit and the second configuration includes a buck-boost converter circuit.