NON-ISOLATED CHARGER WITH BI-POLAR INPUTS

• US 20100270977A1
• Filed: 06/10/2010
• Published: 10/28/2010
• Est. Priority Date: 04/02/2008
• Status: Active Grant

• Current Assignee: American Power Conversion Corporation (Schneider Electric SE)
• Original Assignee: American Power Conversion Corporation (Schneider Electric SE)
• Inventors: Samstad, Jeffrey B.
• Granted Patent: US 7,834,587 B1
• Time in Patent Office: Days
• US Class Current: 320/137
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 9/04 in which the distribution system is disconnected from the normal source and connected to a standby source
• 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 3/1582 Buck-boost converters H02M3/1584 takes precedence

Abstract

Systems and methods are provided for an uninterruptable power supply having a positive DC bus, a neutral DC bus, and a negative DC bus. The uninterruptible power supply includes a battery charger circuit having an inductor, a first charger output, and a second charger output. A first switch connected to a first end of the inductor is configured to couple the positive DC bus with the first charger output. A second switch connected to a second end of the inductor is configured to couple the negative DC bus with the inductor. The neutral DC bus can be coupled to the second charger output. The battery charger circuit can be configured to draw power from at to least one of the positive DC bus and the negative DC bus to charge a battery coupled to the first charger output and the second charger output.

Claims

1. An uninterruptable power supply, comprising:

a positive DC bus, a neutral DC bus, and a negative DC bus;

a battery charger circuit having an inductor, a first charger output and a second charger output;

a first switch having a first end connected to a first end of the inductor, the first switch configured to selectively couple the positive DC bus with the first charger output; and

a second switch having a first end connected to a second end of the inductor, the second switch configured to selectively couple the negative DC bus with the inductor;

wherein the inductor is a single inductor configured between the first end of the first switch and the first end of the second switch;

wherein the neutral DC bus is coupled to the second charger output; and

wherein the battery charger circuit is configured to draw power from at least one of the positive DC bus and the negative DC bus to charge a battery coupled to the first charger output and the second charger output.

2. The uninterruptable power supply of claim 1, comprising:

a control module configured to switch the first switch and the second switch in unison.

9. The uninterruptable power supply of claim 1, wherein the battery charger circuit is configured to concurrently receive current from the positive DC bus and from the negative DC bus.

11. The uninterruptable power supply of claim 1, further comprising:

a control module configured to drive an inductor current of the inductor toward a value between an upper current threshold and a lower current threshold.

13. The uninterruptable power supply of claim 11, wherein:

the battery charger circuit includes a current transformer and a resistor; and

the control module is configured to sample at least one of a transformer voltage and a resistor voltage to determine a value of the inductor current.

25. The uninterruptable power supply of claim 1, comprising:

the first charger output consisting essentially of a direct connection with a first capacitor, a diode, and the battery; and

the second charger output consisting essentially of a direct connection with the first capacitor, a resistor, a second capacitor, the neutral DC bus, and the battery.

26. The uninterruptable power supply of claim 1, wherein the battery charger circuit is an only battery charger circuit configured to draw power from at least one of the positive DC bus and the negative DC bus to charge the battery.

27. The uninterruptable power supply of claim 1, further comprising the battery charger circuit consisting essentially of a single battery charger circuit.

28. The uninterruptable power supply of claim 1, comprising:

the battery charger circuit configured with bi-polar inputs to receive input voltage from a power source.

29. The uninterruptable power supply of claim 1, wherein inductance of the battery charger circuit between the first end of the first switch and the first end of the second switch consists essentially of inductance associated with the inductor during operation of the uninterruptable power supply.

30. The uninterruptable power supply of claim 1, comprising:

the first end of the first switch directly connected to the first end of the inductor; and

the first end of the second switch directly connected to the second end of the inductor.

31. The uninterruptable power supply of claim 1, wherein the second switch is connected to the second end of the inductor and configured to create a current path through the second switch and the inductor, the current path bypassing the first charger output and the second charger output.

3-8. -8. (canceled)

10. (canceled)

12. (canceled)

14. (canceled)

15. A method for charging a battery of an uninterruptable power supply having a positive DC bus, a neutral DC bus, and a negative DC bus, comprising:

selectively coupling;

a first charger output of a battery charger circuit with the positive DC bus by use of a first switch; and

a single inductor of the battery charger circuit with the negative DC bus by use of a second switch to couple the inductor between a first end of the first switch and a first end of the second switch;

coupling a second charger output of the battery charger circuit with the neutral DC bus; and

applying current from at least one of the positive DC bus and the neutral DC bus through the inductor to the battery.

16. The method of claim 15, comprising:

performing a first switching operation on the first switch at a first end of the inductor to couple the positive DC bus with the first battery output; and

performing a second switching operation on the second switch at a second end of the inductor to couple the inductor with the negative DC bus.

23. The method of claim 15, comprising:

drawing a substantially equal amount of power from each of the positive DC bus and the negative DC bus through the battery charger circuit to charge the battery.

32. The method of claim 15, comprising:

controlling the first switch to couple the first charger output with the positive DC bus; and

controlling the second switch to couple the inductor with the negative DC bus.

33. The method of claim 15, comprising:

directly connecting the first end of the first switch to the first end of the inductor; and

directly connecting the first end of the second switch to the second end of the inductor.

34. The method of claim 15, comprising:

connecting the second switch to the second end of the inductor to create a current path through the second switch and the inductor, the current path bypassing the first charger output and the second charger output.

17-22. -22. (canceled)

24. An uninterruptable power supply, comprising:

a positive DC bus, a neutral DC bus, and a negative DC bus;

a battery charger circuit having a single inductor, a first charger output, and a second charger output;

means for selectively controlling;

a first switch to couple the first charger output with the positive DC bus; and

a second switch to couple the inductor with the negative DC bus;

the second charger output coupled to the neutral DC bus; and

the battery charger circuit configured to pass current from at least one of the positive DC bus and the neutral DC bus through the inductor to charge a battery.

35. The uninterruptable power supply of claim 24, wherein the second switch is configured to create a current path through the second switch and the inductor, the current path bypassing the first charger output and the second charger output.