Single-stage power converter and an uninterruptible power supply using same

• US 6,515,883 B2
• Filed: 03/28/2001
• Issued: 02/04/2003
• Est. Priority Date: 03/28/2001
• Status: Expired due to Fees

• Current Assignee: Powerware Corporation (Eaton Corporation PLC.)
• Original Assignee: Powerware Corporation (Eaton Corporation PLC.)
• Inventors: Wade, Joseph R.
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US09/820,261
• Publication Number:
  US 20020181262A1
• Time in Patent Office: 678 Days
• Field of Search: 363/15, 363/16, 363/34, 363/123, 363/124, 363/126, 363/131, 323/222, 323/220
• US Class Current: 363/123
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: H02M 3/005 using Cuk converters
• CPC Class Codes: H02M 3/1557 Single ended primary inductor converters [SEPIC]
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

Abstract

Presented is a single-stage power converter topology allowing for power factor correction during operation. The topology utilizes an integration of Ćuk converter and single-ended primary inductance converter (SEPIC) topologies to provide AC-to-AC, AC-to-DC, DC-to-AC, and AC/DC-to-AC operation. Shared use of the Ćuk converter'"'"'s output inductor by the SEPIC-type circuit elements provides continuous output current, typically unknown to a SEPIC converter. Application of the single-stage power converter topologies may be had in a line conditioner circuit, a battery charger circuit, and as an uninterruptible power supply (UPS).

Claims

1. A single-stage power converter, comprising:

an input adapted to receive an electric power input from an external source of electric power;

a first circuit portion coupled to said input, said first circuit portion operative during a first phase of operation to produce an output power to an external coupled load;

a second circuit portion coupled to said input, said second circuit portion operative during a second phase of operation to produce said output power to the external coupled load; and

wherein said first circuit portion is configured as one of a Ć

uk converter and a single-ended primary inductance converter (SEPIC) and said second circuit portion is configured as one of a Ć

uk converter and a single-ended primary inductance converter (SEPIC); and

wherein said output power produced by each of said first and said second circuit portions is continuous.

2. The converter of claim 1, wherein said first circuit portion includes an output inductor through which said output power is supplied during said first phase, and wherein said second circuit portion shares said output inductor through which said output power is supplied during said second phase.

3. The converter of claim 2, wherein the input electric power is AC, the output electric power is DC, and wherein said first circuit portion is configured as a Ć

uk converter and said second portion is configured as a SEPIC converter.

4. The converter of claim 3, wherein said first circuit portion is operative during a negative half-cycle of the AC input electric power, and wherein said second circuit portion is operative during a positive half-cycle of the AC input electric power.

5. The converter of claim 2, wherein the input electric power is AC, the output electric power is AC, and said first circuit portion is configured as a Ć

uk converter and wherein said second circuit portion is configured as a Ć

uk converter.

6. The converter of claim 5, wherein said first circuit portion is operative during a positive half-cycle of the AC input electric power, and wherein said second circuit portion is operative during a negative half-cycle of the AC input electric power, and wherein the output electric power is inverted relative to the input electric power.

7. The converter of claim 2, wherein the input electric power is AC, the output electric power is AC, and said first circuit portion is configured as a SEPIC converter and wherein said second circuit portion is configured as a SEPIC converter.

8. The converter of claim 7, wherein said first circuit portion is operative during a positive half-cycle of the AC input electric power, and wherein said second circuit portion is operative during a negative half-cycle of the AC input electric power, and wherein the output electric power is non-inverted relative to the input electric power.

9. The converter of claim 2, wherein the input electric power is DC, the output electric power is AC, and said first circuit portion is configured as a Ć

uk converter and wherein said second circuit portion is configured as a SEPIC converter.

10. The converter of claim 9, wherein said first circuit portion is operative to construct a negative half-cycle of the AC output electric power, and wherein said second circuit portion is operative to construct a positive half-cycle of the AC output electric power.

11. A single-stage power converter, comprising:

an input adapted to receive an electric power input from an external source of electric power;

a first circuit portion coupled to said input, said first circuit portion operative during a first phase of operation to produce an output power to an external coupled load;

a second circuit portion coupled to said input, said second circuit portion operative during a second phase of operation to produce said output power to the external coupled load; and

wherein said first circuit portion is configured as one of a Ć

uk converter and a single-ended primary inductance converter (SEPIC) and said second circuit portion is configured as one of a Ć

uk converter and a single-ended primary inductance converter (SEPIC);

wherein said output power produced by each of said first and said second circuit portions is continuous;

wherein said first circuit portion includes an output inductor through which said output power is supplied during said first phase, and wherein said second circuit portion shares said output inductor through which said output power is supplied during said second phase; and

a third circuit portion coupled to said input, said third circuit portion operative during a third phase of operation to produce said output power to the external coupled load, said third circuit portion is configured as one of a Ć

uk converter and a single-ended primary inductance converter (SEPIC), and wherein said third circuit portion shares said output inductor through which said output power is supplied during said third phase, and wherein at least one of said first, second, and third circuit portions is configured as a Ć

uk converter and at least one other of said first, said second, and said third circuit portions is configured as a SEPIC converter.

12. The converter of claim 11, wherein said input is further adapted to selectively receive an electric power input from a first external source of DC electric power and a second external source of AC electric power.

13. The converter of claim 12, wherein said input receives the electric power input form the first external source of DC electric power, wherein the output electric power is AC, and wherein said first circuit portion is configured as a Ć

uk converter and said second circuit portion is configured as a SEPIC converter, and wherein said first circuit portion is operative to construct a negative half-cycle of the AC output electric power, and wherein said second circuit portion is operative to construct a positive half-cycle of the AC output electric power.

14. The converter of claim 12, wherein said input receives the electric power input form the second external source of AC electric power, wherein the output electric power is AC, and wherein said second circuit portion is configured as a SEPIC converter and said third circuit portion is configured as a SEPIC converter, and wherein said second circuit portion is operative to construct a positive half-cycle of the AC output electric power, and wherein said third circuit portion is operative to construct,a negative half-cycle of the AC output electric power.

15. A single-stage AC-to-AC converter, comprising:

an input adapted to receive AC electric power from an external source;

a first circuit portion forming a first Ć

uk converter having an input inductor, an output inductor, and a line capacitor; and

a second circuit portion forming, in conjunction with said input inductor, said output inductor, and said line capacitor, a second Ć

uk converter, said second Ć

uk converter being oriented in opposite polarity to said first Ć

uk converter.

16. The converter of claim 15, wherein said first Ć

uk converter is operative during a positive half-cycle of the AC electric power from the external source to generate a negative half-cycle of an output AC electric power, and wherein said second Ć

uk converter is operative during a negative half-cycle of the AC electric power from the external source to generate a positive half-cycle of the output AC electric power.

17. The converter of claim 15, wherein said first Ć

uk converter includes a first power switching device and a first series connected diode and said second Ć

uk converter includes a second power switching device and a second series connected diode, said first power switching device and said first series connected diode coupled in opposite parallel orientation to said second power switching device and said second series connected diode.

18. A single-stage AC-to-DC converter, comprising:

an input adapted to receive AC electric power from an external source;

a first circuit portion forming a Ć

uk converter having an input inductor and an output inductor; and

a second circuit portion forming, in conjunction with said input inductor of said Ć

uk converter, a single-ended primary inductance converter (SEPIC), said SEPIC converter being coupled to said output inductor of said Ć

uk converter to maintain a constant output current during operation of said SEPIC converter, said SEPIC converter further being oriented in opposite polarity to said Ć

uk converter.

19. The converter of claim 18, wherein reverse power flow through said first circuit portion and said second circuit portion is prohibited by blocking diodes.

20. The converter of claim 18, wherein said first circuit portion is operative during a negative half-cycle of the AC electric power to produce a positive DC output, and wherein said second circuit portion is operative during a positive half-cycle of the AC electric power to produce a positive DC output, said shared output inductor ensuring constant output current during operation of said second circuit portion.

21. An uninterruptible power supply (UPS) operative to supply AC output power to connected loads from both AC line power, and backup DC battery power in the event of loss or severe degradation of AC line power, comprising:

input source selection circuitry adapted to receive the AC line power and the backup DC battery power;

a first circuit portion forming a Ć

uk converter having an input inductor and an output inductor; and

a second circuit portion forming, in conjunction with said input inductor of said Ć

uk converter, a first single-ended primary inductance converter (SEPIC), said first SEPIC converter being coupled to said output inductor of said Ć

uk converter to maintain a constant output current during operation of said first SEPIC converter, said first SEPIC converter further being oriented in opposite polarity to said Ć

uk converter; and

a third circuit portion forming, in conjunction with said input inductor of said Ć

uk converter, a second single-ended primary inductance converter (SEPIC), said second SEPIC converter being coupled to said output inductor of said Ć

uk converter to maintain a constant output current during operation of said second SEPIC converter, said second SEPIC converter further being oriented in like polarity to said Ć

uk converter.

22. The UPS of claim 21, wherein said input source selection circuitry selects the AC line power, wherein said second SEPIC converter is operative during a positive half-cycle of the AC line power to produce a positive half-cycle of the AC output power through said shared output inductor of said Ć

uk converter, and wherein said first SEPIC converter is operative during a negative half-cycle of the AC line power to produce a negative half-cycle of the AC output power through said shared output inductor of said Ć

uk converter.

23. The UPS of claim 21, wherein said input source selection circuitry selects the backup DC battery power, wherein said second SEPIC converter is operative to produce a positive half-cycle of the AC output power through said shared output inductor of said Ć

uk converter, and wherein said Ć

uk converter is operative to produce a negative half-cycle of the AC output power.