Multi-Level Parallel Power Converters

• US 20120092908A1
• Filed: 04/25/2011
• Published: 04/19/2012
• Est. Priority Date: 10/19/2010
• Status: Active Grant

• Current Assignee: Astec International Limited (Emerson Electric Company)
• Original Assignee: Astec International Limited (Emerson Electric Company)
• Inventors: Wang, Lin Guo, Piotr, Markowski, Bu, Hong Fei
• Granted Patent: US 8,885,371 B2
• Time in Patent Office: Days
• US Class Current: 363/71
• CPC Class Codes: H01F 27/385 for reducing harmonics
• CPC Class Codes: H01F 30/02 Auto-transformers
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

Multi-level power converters are disclosed. In one embodiment, a multi-level power converter includes an input for receiving an input voltage and a converter output for providing a variable output voltage. The multi-level power converter includes a plurality of switching circuits. Each switching circuit is connected to the input in parallel with each other switching circuit. Each switching circuit includes an output. Each switching circuit is selectively operable to couple its output to the input voltage or a reference voltage. The multi-level power converter includes a parallel multi-winding autotransformer (PMA). The PMA includes a plurality of windings and a magnetic core having a plurality of magnetically connected columns. Each winding is positioned around a different one of the columns and has a beginning and an end. The output of each switching circuit is coupled to the beginning of a different winding. The end of each winding is connected to the converter output in parallel with each other winding.

Claims

1. A multi-level power converter comprising:

an input for receiving an input voltage;

a converter output for providing a variable output voltage;

a plurality of switching circuits, each switching circuit connected to the input in parallel with each other switching circuit, each switching circuit including an output, each switching circuit selectively operable to couple its output to the input voltage or a reference voltage; and

a parallel multi-winding autotransformer (PMA), the PMA including a plurality of windings and a magnetic core having a plurality of magnetically connected columns, each winding positioned around a different one of the columns, each winding having a beginning and an end, the output of each switching circuit coupled to the beginning of a different winding, the end of each winding connected to the converter output in parallel with each other winding.

2. The multi-level power converter of claim 1 wherein the plurality of windings are all wound in a same direction.

3. The multi-level power converter of claim 2 wherein the plurality of windings all have a same number of turns.

4. The multi-level power converter of claim 1 wherein each switching circuit includes a first switch and a second switch.

5. The multi-level power converter of claim 4 wherein each switching circuit is configured to couple its output to the input voltage when its first switch is on and its second switch is off.

6. The multi-level power converter of claim 5 wherein each switching circuit is configured to couple its output to the reference voltage when its first switch is off and its second switch is on.

7. The multi-level power converter of claim 1 wherein a magnitude of the output voltage is a function of how many of the switching circuits have their respective outputs coupled to the input voltage at a given time.

8. The multi-level power converter of claim 1 wherein the PMA is configured to cause currents provided by the switching circuits to be about equal.

9. The multi-level power converter of claim 1 wherein the power converter does not include an output capacitor.

10. The multi-level power converter of claim 1 further comprising a controller configured for selectively operating the switching circuits to control the variable output voltage.

11. The multi-level power converter of claim 1 wherein the reference voltage is about zero volts.

12. The multi-level power converter of claim 1 further comprising an additional switching circuit, the additional switching circuit connected to an additional input voltage, the additional switching circuit including an output, the additional switching circuit selectively operable to couple its output to the additional input voltage or the reference voltage, the output of the additional switching circuit coupled to the beginning of one of the plurality of windings, and the end of said winding connected to the converter output.

13. A multi-level power converter comprising:

an input for receiving an input voltage, the input including a first input node and a second input node;

an output for providing a variable output voltage;

a parallel magnetic component including a magnetic core, a first winding, a second winding and a third winding, the magnetic core including a first column, a second column, and a third column, the first, second and third columns magnetically connected to each other, the first winding positioned around the first column, the second winding positioned around the second column and the third winding positioned around the third column, each of the first, second, and third windings including an input end and an output end, the first second and third windings wound in a same direction with respect to their input ends, and the output end of each of the first, second, and third windings are galvanically connected together;

a first switching circuit coupled to the first input node, the second input node and the input end of the first winding;

a second switching circuit coupled to the first input node, the second input node and the input end of the second winding; and

a third switching circuit coupled to the first input node, the second input node and the input end of the third winding.

14. The multi-level power converter of claim 13 wherein each of the first, second and third switching circuits is operable to selectively couple its output to the first input node and the second input node.

15. The multi-level power converter of claim 14 wherein the first, second and third windings all have a same number of turns.

16. The multi-level power converter of claim 14 wherein each of the first, second and third switching circuits includes a first switch and a second switch and each of the first, second and third switching circuits is configured to couple its output to the first input node when its first switch is on and to couple its output to the second input node when its second switch is on.

17. The multi-level power converter of claim 13 wherein the parallel magnetic component is configured to cause currents provided by the first, second and third switching circuits to be about equal.

18. The multi-level power converter of claim 13 wherein the multi-level power supply does not include an output capacitor.

19. The multi-level power converter of claim 13 further comprising a controller configured for selectively operating the first, second and third switching circuits to control the variable output voltage.

20. The multi-level power converter of claim 13 further comprising a third input node for receiving an additional input voltage and a fourth switching circuit coupled to the third input node and the second input node, and wherein the magnetic core includes a fourth column and a fourth winding, the fourth column is magnetically connected to the first, second, and third columns, the fourth winding is positioned around the fourth column, the fourth winding includes an input end and an output end, the fourth winding is wound in the same direction as the first, second and third windings, the output end of the fourth windings is galvanically connected to the output end of the first, second, and third windings, and the input end of the fourth winding is connected to the fourth switching circuit.