Power factor correction drive circuit topologies and control for switched reluctance machines

• US 8,878,467 B2
• Filed: 08/05/2013
• Issued: 11/04/2014
• Est. Priority Date: 03/29/2010
• Status: Active Grant

• Current Assignee: Regal Beloit America, Inc.
• Original Assignee: Regal Beloit America, Inc.
• Inventors: Ramu, Krishnan
• Primary Examiner(s): Ro, Bentsu
• Assistant Examiner(s): DINH, THAI T
• Application Number:
  US13/959,334
• Publication Number:
  US 20140035490A1
• Time in Patent Office: 456 Days
• Field of Search: 318/254.1, 318/254.2, 318/701, 318/729, 318/438, 310/49.43, 310/216.075, 310/216.107, 310/12.18
• US Class Current: 318/254.1
• CPC Class Codes: H02K 1/14 Stator cores with salient poles
• CPC Class Codes: H02K 2213/03 Machines characterised by numerical values, ranges, mathematical expressions or similar information
• CPC Class Codes: H02K 3/18 Windings for salient poles
• CPC Class Codes: H02P 6/14 Electronic commutators

Abstract

Drive circuits that provide power factor correction and input current waveform shaping for controlling the speed and torque in a switched reluctance machine (SRM). The machine'"'"'s phase windings are split into two segments, one of which is used for active power factor correction, input ac current waveform shaping and partial torque generation and the other of which is used for torque generation.

Claims

1. A power converter for supplying power to a motor, the power converter comprising for a phase of the motor:

a unidirectional current element that conveys current in a single direction;

first and second series-connected windings for the motor phase;

a capacitive element; and

first and second switches that each conducts current when activated and does not conduct current when deactivated, wherein;

the unidirectional current element, capacitive element, first and second windings, and first and second switches are interconnected such that when interconnected with a single-phase alternating current supply through a full-wave bridge rectifier;

a first operational mode of the power converter exists in which current is conducted through the first switch and the first winding, the conduction of current through the first winding imparting a motive force upon a rotor of the motor,

a second operational mode of the power converter exists in which current is not conducted through the first switch and energy is transferred from the first winding to the capacitive element by the conduction of current through the first winding, the unidirectional current element, and the capacitive element, and

a third operational mode exists in which energy stored in the capacitor during the second operational mode is discharged by the conduction of current through the first and second switches, capacitive element, and second winding, the conduction of current through the second winding imparting a motive force upon the motor rotor.

2. A power converter for supplying power to a motor, the power converter comprising for two phases of the motor:

no more than three diodes;

a single capacitor; and

no more than three switches that each conducts current when activated and does not conduct current when deactivated, wherein;

the three diodes, capacitor, and three switches are interconnected such that when interconnected with a single-phase alternating current supply through a full-wave bridge rectifier, first and second series-connected windings for a first of the two motor phases, and third and fourth series-connected phase windings for a second of the two motor phases;

a first operational mode of the power converter exists in which current is conducted through a first of the three switches and the first winding, but no current is conducted through a second of the three switches,

a second operational mode of the power converter exists in which current is conducted through the second switch and the second winding, but no current is conducted through the first switch,

a third operational mode exists in which energy stored in the first winding during the first operational mode is discharged into the capacitor by the conduction of current through the first winding, a first of the three diodes, and the capacitor,

a fourth operational mode exists in which energy stored in the second winding during the second operational mode is discharged into the capacitor by the conduction of current through the second winding, a second of the three diodes, and the capacitor,

a fifth operational mode exists in which energy stored in the capacitor during the third or fourth operational modes is discharged by the conduction of current through the third winding, the first switch, and a third of the three switches, and

a sixth operational mode exists in which energy stored in the capacitor during the third or fourth operational modes is discharged by the conduction of current through the fourth winding and the second and third switches.

3. The power converter of claim 2, further comprising:

the first and second series-connected windings and the third and fourth series-connected windings, wherein

the conduction of current through each of the first, second, third, and fourth windings imparts a motive force upon a rotor of the motor.

4. A power converter for supplying power to a motor, the power converter comprising:

a capacitive element; and

first, second, and third switches that each conducts current in a conductive state and does not conduct current in a non-conductive state, wherein;

the capacitive element and first, second, and third switches are interconnected such that when interconnected with a single-phase alternating current supply, through a full-wave bridge rectifier, first and second series-connected windings constituting a first phase of the motor, and third and fourth series-connected windings constituting a second phase of the motor;

energy is transferred from the current supply to the first winding, by the conveyance of current through the first switch and first winding, when the first switch is in the conductive state,

energy stored in the first winding is transferred to the capacitive element, by the conveyance of current through the first winding and capacitive element, when the first switch is in the non-conductive state,

energy stored in the capacitive element is transferred to the second winding, by the conveyance of current through the first and second switches and the second winding, when the first and second switches each are in the conductive state,

energy is transferred from the current supply to the third winding, by the conveyance of current through the third switch and third winding, when the third switch is in the conductive state,

energy stored in the third winding is transferred to the capacitive element, by the conveyance of current through the third winding and the capacitive element, when the third switch is in the non-conductive state, and

energy stored in the capacitive element is transferred to the fourth winding, by the conveyance of current through the second and third switches, the fourth winding and the capacitive element, when the second and third switches each are in the conductive state.

5. The power converter of claim 4, further comprising:

a first unidirectional current element that conducts current in a single direction, wherein;

the first unidirectional current element, capacitive element, and first, second, and third switches are interconnected such that when interconnected with the single-phase alternating current supply, through the full-wave bridge rectifier, and the first, second, third, and fourth windings;

the energy stored in the first winding is transferred to the capacitive element, by the conveyance of current through the first winding, first unidirectional current element and capacitive element, when the first and second switches each are in the non-conductive state.

6. The power converter of claim 5, further comprising:

a second unidirectional current element that conducts current in a single direction, wherein;

the first and second unidirectional current elements, capacitive element, and first, second, and third switches are interconnected such that when interconnected with the single-phase alternating current supply, through the full-wave bridge rectifier, and the first, second, third, and fourth windings;

energy stored in the third winding is transferred to the capacitive element, by the conveyance of current through the third winding, second unidirectional current element and capacitive element, when the third switch is in the non-conductive state.

7. The power converter of claim 6, further comprising:

a third unidirectional current element that conducts current in a single direction, wherein;

the first, second, and third unidirectional current elements, capacitive element, and first, second, and third switches are interconnected such that when interconnected with the single-phase alternating current supply, through the full-wave bridge rectifier, and the first, second, third, and fourth windings;

energy stored in the second winding is discharged by the conduction of current through the second winding, third unidirectional current element and first switch, when the first switch is in the conductive state and the second switch is in the non-conductive state, and

energy stored in the fourth winding is discharged by the conduction of current through the fourth winding, third unidirectional current element and third switch, when the third switch is in the conductive state and the second switch is in the non-conductive state.

8. The power converter of claim 4, further comprising:

first, second, and third unidirectional current elements that each conducts current in a single direction, wherein;

the first, second, and third unidirectional current elements, capacitive element, and first, second, and third switches are interconnected such that when interconnected with the single-phase alternating current supply through the full-wave bridge rectifier and the first, second, third, and fourth windings;

energy stored in the second winding is transferred to the capacitive element, by the conveyance of current through the second winding, first and second unidirectional current elements and capacitive element, when the first and second switches each are in the non-conductive state, and

energy stored in the fourth winding is transferred to the capacitive element, by the conveyance of current through the fourth winding, second and third unidirectional current elements and capacitive element, when the second and third switches each are in the non-conductive state.

9. The power converter of claim 8, wherein:

energy stored in the first winding is transferred to the capacitive element, by the conveyance of current through the first winding, first unidirectional current element and capacitive element, when the first and second switches each are in the non-conductive state, and

energy stored in the third winding is transferred to the capacitive element, by the conveyance of current through the third winding, third unidirectional current element and capacitive element, when the second and third switches each are in the non-conductive state.

10. A power converter for supplying power to a motor, the power converter comprising:

first and second unidirectional current elements that each conducts current in a single direction;

first and second capacitive elements; and

first and second switches that each conducts current in a conductive state and does not conduct current in a non-conductive state, wherein;

the first and second unidirectional current elements, first and second capacitive elements, and first and second switches are interconnected such that when interconnected with a single-phase alternating current supply through a full-wave bridge rectifier, first and second windings constituting a first motor phase, and third and fourth windings constituting a second motor phase;

energy is transferred from the current supply to the first winding, by the conveyance of current through the first switch and first winding, when the first switch is in the conductive state,

energy stored in the first winding is transferred to the first capacitive element, by the conveyance of current through the first winding, first unidirectional current element and first capacitive element, when the first switch is in the non-conductive state,

energy stored in the first capacitive element is transferred to the second winding, by the conveyance of current through the first capacitive element and second winding,

energy is transferred from the current supply to the third winding, by the conveyance of current through the second switch and third winding, when the second switch is in the conductive state,

energy stored in the third winding is transferred to the second capacitive element, by the conveyance of current through the third winding, second unidirectional current element and second capacitive element, when the second switch is in the non-conductive state, and

energy stored in the second capacitive element is transferred to the fourth winding, by the conveyance of current through the second capacitive element and fourth winding.

11. The power converter of claim 10, wherein the first capacitive element and second winding are electrically connected in parallel such that the same voltage potential exists across the first capacitive element and second winding.

12. The power converter of claim 11, wherein the second capacitive element and fourth winding are electrically connected in parallel such that the same voltage potential exists across the first capacitive element and second winding.

13. The power converter of claim 10, wherein a series connection of the first winding and first unidirectional current element is electrically connected in parallel with the first capacitive element such that the same voltage potential exists across the first capacitive element and the series connection of the first winding and first unidirectional current element.

14. The power converter of claim 13, wherein a series connection of the third winding and second unidirectional current element is electrically connected in parallel with the second capacitive element such that the same voltage potential exists across the second capacitive element and the series connection of the third winding and second unidirectional current element.

15. A power converter comprising:

first, second, and third unidirectional current elements that each conducts current in only one direction between a current input terminal and a current output terminal;

a capacitive element for storing energy across first and second terminals; and

first, second, and third switches that each conducts current between a current input terminal and a current output terminal when in a conductive state and does not conduct current when in a non-conductive state, wherein;

the first terminal of the capacitive element, the current input terminal of the second switch, and the current output terminals of the first and third unidirectional current elements are directly connected by a first node,

the current input terminal of the first unidirectional current element is directly connected to the current input terminal of the first switch by a second node,

the current output terminal of the second switch is directly connected to the current output terminal of the second unidirectional current element by a third node,

the second terminal of the capacitive element is directly connected to the current output terminals of the first and third switches, and the current input terminal of the second unidirectional current element by a fourth node, and

the current input terminals of the third switch and the third unidirectional current element are directly connected by a fifth node.

16. The power converter of claim 15, further comprising:

first and second motor windings, wherein;

the first winding has a terminal directly connected to the second node, and

the second winding has a terminal directly connected to the second node and another terminal directly connected to the third node.

17. The power converter of claim 15, further comprising:

first, second, third and fourth motor windings, wherein;

the first winding has a terminal directly connected to the second node,

the second winding has a terminal directly connected to the second node and another terminal directly connected to the third node,

the third winding has a terminal directly connected to the fifth node, and

the fourth winding has a terminal directly connected to the third node and another terminal directly connected to the fifth node.

18. The power converter of claim 15, further comprising:

a fourth unidirectional current element that conducts current in only one direction between a current input terminal and a current output terminal; and

a fourth switch that conducts current between a current input terminal and a current output terminal when in a conductive state and does not conduct current when in a non-conductive state, wherein;

the current input terminal of the fourth switch is directly connected to the first node,

the current input terminal of the fourth unidirectional current element is directly connected to the fourth node, and

the current output terminals of the fourth switch and fourth unidirectional current element are directly connected by a sixth node.

19. The power converter of claim 18, further comprising:

first, second, third and fourth motor windings, wherein;

the first winding has a terminal directly connected to the second node,

the second winding has a first terminal directly connected to the second node and a second terminal directly connected to the third node,

the third winding has a terminal directly connected to the fifth node, and

the fourth winding has a first terminal directly connected to the fifth node and a second terminal directly connected to the sixth node.

20. A power converter comprising:

first and second unidirectional current elements that each conducts current in only one direction between a current input terminal and a current output terminal;

first and second capacitive elements that each stores energy across first and second terminals;

first and second switches that each conducts current between a current input terminal and a current output terminal when in a conductive state and does not conduct current when in a non-conductive state;

first and second motor windings constituting a first motor phase, each of the first and second windings having first and second terminals;

third and fourth motor windings constituting a second motor phase, each of the third and fourth windings having first and second terminals, wherein;

the first terminals of the first and second capacitive elements and the first terminals of the first, second, third, and fourth windings are directly connected by a first node,

the second terminal of the first winding and the current input terminals of the first switch and first unidirectional current element are directly connected by a second node,

the second terminals of the first capacitive element and the second winding and the current output terminal of the first unidirectional current element are directly connected by a third node,

the second terminal of the third winding and the current input terminals of the second switch and second unidirectional current element are directly connected by a fourth node,

the second terminals of the second capacitive element and the fourth winding and the current output terminal of the second unidirectional current element are directly connected by a fifth node, and

the current output terminals of the first and second switches are directly connected by a sixth node.

21. A power converter for supplying power to a motor, the power converter comprising:

a capacitive element; and

first, second, third, and fourth switches that each conducts current in a conductive state and does not conduct current in a non-conductive state, wherein;

the capacitive element and first, second, third, and fourth switches are interconnected such that when interconnected with a single-phase alternating current supply, through a full-wave bridge rectifier, first and second series-connected windings constituting a first phase of the motor, and third and fourth series-connected windings constituting a second phase of the motor;

energy is transferred from the current supply to the first winding, by the conveyance of current through the first switch and first winding, when the first switch is in the conductive state,

energy stored in the first winding is transferred to the capacitive element, by the conveyance of current through the first winding and capacitive element, when the first switch is in the non-conductive state,

energy stored in the capacitive element is transferred to the second winding, by the conveyance of current through the first and second switches and the second winding, when the first and second switches each are in the conductive state, energy is transferred from the current supply to the third winding, by the conveyance of current through the third switch and third winding, when the third switch is in the conductive state,

energy stored in the third winding is transferred to the capacitive element, by the conveyance of current through the third winding and the capacitive element, when the third switch is in the non-conductive state, and

energy stored in the capacitive element is transferred to the fourth winding, by the conveyance of current through the third and fourth switches, the fourth winding and the capacitive element, when the third and fourth switches each are in the conductive state.

22. The power converter of claim 21, further comprising:

first, second, third, and fourth unidirectional current elements that each conducts current in a single direction, wherein;

the first, second, third, and fourth unidirectional current elements, capacitive element, and first, second, third, and fourth switches are interconnected such that when interconnected with the single-phase alternating current supply through the full-wave bridge rectifier and the first, second, third, and fourth windings;

energy stored in the second winding is transferred to the capacitive element, by the conveyance of current through the second winding, first and second unidirectional current elements and capacitive element, when the first and second switches each are in the non-conductive state, and

energy stored in the fourth winding is transferred to the capacitive element, by the conveyance of current through the fourth winding, third and fourth unidirectional current elements and capacitive element, when the third and fourth switches each are in the non-conductive state.

23. The power converter of claim 22, wherein:

the energy stored in the first winding is transferred to the capacitive element, by the conveyance of current through the first winding, first unidirectional current element and capacitive element, when the first and second switches each are in the non-conductive state, and

the energy stored in the third winding is transferred to the capacitive element, by the conveyance of current through the third winding, third unidirectional current element and capacitive element, when the first and second switches each are in the non-conductive state.

24. The power converter of claim 21, further comprising:

the first and second series-connected windings and the third and fourth series-connected windings, wherein

the conduction of current through each of the first, second, third, and fourth windings imparts a motive force upon a rotor of the motor.