Power conditioning system for energy sources

• US 7,372,709 B2
• Filed: 09/19/2005
• Issued: 05/13/2008
• Est. Priority Date: 09/11/2003
• Status: Expired due to Fees

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Acharya, Kaustuva, Burra, Rajni K., Mazumder, Sudip K.
• Primary Examiner(s): HAN, YOUNGHUIE JESSICA
• Application Number:
  US11/230,312
• Publication Number:
  US 20060062034A1
• Time in Patent Office: 967 Days
• Field of Search: 363/16, 363/17, 363/20, 363/21.01, 363/34, 363/37, 363/39, 363/131, 363/132, 363/2, 363/4, 363/8, 323/282
• US Class Current: 363/16
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/30 The power source being a fuel cell
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02M 1/0095 Hybrid converter topologies, e.g. NPC mixed with flying capacitor, thyristor converter mixed with MMC or charge pump mixed with buck
• CPC Class Codes: H02M 7/4807 having a high frequency intermediate AC stage
• CPC Class Codes: H02M 7/4837 Flying capacitor converters
• CPC Class Codes: H02M 7/487 Neutral point clamped inverters
• CPC Class Codes: H02M 7/53875 with analogue control of three-phase output
• CPC Class Codes: H02M 7/5395 by pulse-width modulation
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

Apparatus for conditioning power generated by an energy source includes an inverter for converting a DC input voltage from the energy source to a square wave AC output voltage, and a converter for converting the AC output voltage from the inverter to a sine wave AC output voltage.

Claims

1. Apparatus for conditioning power generated by an energy source, comprising:

an inverter for converting a first DC input voltage to a first AC output voltage;

a multiphase first converter for converting said first AC output voltage from said inverter to a second AC output voltage; and

a second converter for increasing a voltage output by the energy source to said first DC input voltage, said second converter including a coupled inductor having a first winding for conducting DC current and a second winding for conducting AC current of said voltage output by the energy source for generating a substantially ripple free current from said voltage output.

2. The apparatus as defined in claim 1, wherein said first AC output voltage comprises a high frequency square wave AC output voltage and said second AC output voltage comprises a sine wave AC output voltage.

3. The apparatus as defined in claim 2, wherein said inverter comprises a plurality of switches that are turned on and off at a predetermined duty pulse to generate said high frequency square wave AC output voltage.

4. The apparatus as defined in claim 3, wherein said plurality of switches of said inverter are connected in a multi-level arrangement with said first AC output voltage being output between a select pair of said switches.

5. The apparatus as defined in claim 2, wherein said converter is sine wave modulated to generate said sine wave AC output voltage.

6. The apparatus as defined in claim 2, wherein said first converter comprises a pair of bidirectional switches for each phase of said sine wave AC output voltage.

7. The apparatus as defined in claim 1, wherein energy source comprises at least one fuel cell (FC).

8. The apparatus as defined in claim 1, wherein said energy source comprises a photovoltaic array.

9. The apparatus as defined in claim 1, further comprising an active power filter connected to input of said first converter for reducing a low frequency ripple current in said first DC input voltage.

10. The apparatus as defined in claim 1, further comprising a transformer for transmitting said first AC output voltage from said inverter to said first converter.

11. The apparatus as defined in claim 1, wherein said multiphase first converter comprises a full bridge AC/AC converter.

12. Apparatus for conditioning power generated by an energy source, comprising:

a boost converter for increasing a voltage output by the energy source to a first DC input voltage, said boost converter including a coupled inductor having a first winding conducting DC current and a second winding conducting AC current;

a DC/AC inverter for converting said first DC input voltage to a first AC output voltage;

a multiphase AC/AC converter for converting said first AC output voltage from said inverter to a second AC output voltage; and

means for transmitting said first AC output voltage from said inverter to said AC/AC converter.

13. The apparatus as defined in claim 12, wherein said DC/AC comprises a plurality of switches connected in a multi-level arrangement with said first AC output voltage being output between a select pair of said switches.

14. The apparatus as defined in claim 12, wherein said AC/AC converter comprises a pair of bidirectional switches for each phase of said sine wave AC output voltage.

15. The apparatus as defined in claim 12, wherein said multiphase AC/AC converter comprises a full bridge AC/AC converter.

16. A power electronic system for conditioning power from a fuel cell, such system comprising:

a boost converter adapted to boost a voltage of a direct current (DC) output voltage from the fuel cell, and to substantially cancel input ripple current at the fuel cell through mutual inductance;

a high frequency converter with a plurality of switching elements adapted to convert the direct current (DC) voltage from the boost converter into a square wave alternating current (AC) voltage; and

an AC to AC converter adapted to reduce a current in each of the switching elements of the high frequency converter substantially to zero before a switching element is switched for converting the AC voltage from the high frequency converter to AC output voltage.

17. The apparatus as defined in claim 16, wherein said boost converter comprises a coupled inductor having a first winding conducting DC current and a second winding conducting AC current.