Soft chopping for switched reluctance generators
AssigneeDelphi Technologies, Inc.
InventorGabriel Gallegos-Lopez
Life of this patent
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Abstract
The switched reluctance machine providing soft chopping in the output current controls the voltage across the phase winding. When the current through the phase winding in the generating mode reaches a first predetermined value, the voltage across the phase winding is reversed and as a result, the current through the phase winding decreases. When the phase winding current reaches a second value, the phase winding is shorted so that the current increases due to the positive back-EMF through the phase winding until the first predetermined value is again reached, at which time the voltage across the phase winding is again reversed.
Claims32
An apparatus for controlling a switched reluctance machine, wherein the switched reluctance machine includes a plurality of rotor and stator poles and a plurality of phase windings on one or more of the stator poles, and wherein the switched reluctance machine is responsive to a voltage bus, said apparatus comprising:
- for each phase winding:
- a first switch connected between a first terminal of the voltage bus and a first terminal of the phase winding;
- a second switch connected between a second terminal of the voltage bus and a second terminal of the phase winding;
- a first unidirectional conduction device having a first terminal connected to the first terminal of the voltage bus and a second terminal connected to the second terminal of the phase winding, wherein said first unidirectional conduction device conducts current only in the direction from the second terminal to the first terminal thereof;
- a second unidirectional conduction device having a first terminal connected to the first terminal of the phase winding and a second terminal connected to the second terminal of the voltage bus, wherein said second unidirectional conduction device conducts current only in the direction from the second terminal to the first terminal thereof;
- wherein during at least a portion of the time when the rotor and stator poles are approaching, each of said first and second switches are closed and current flows from the first terminal of the voltage bus through the serial connection of said first switch, the phase winding and said second switch;
- wherein when the phase winding current is at a first predetermined value while the inductance of the rotor and stator poles of the phase winding is decreasing, opening said first and second switches, such that current flows from the second terminal of the voltage bus serially through said second unidirectional conduction device, from the first to the second terminals of the phase winding and through said first unidirectional conduction device to the first terminal of the voltage bus, after which the phase winding current begins to decrease;
- wherein when the phase winding current is at a second predetermined value, closing said first switch such that current flows through a short circuit loop comprising said first switch, the phase winding and said first unidirectional conduction device, after which the phase winding current begins to increase;
- wherein when the phase winding current is at the first predetermined value, opening said first switch such that the current flows from the second terminal of the voltage bus serially through said second unidirectional conduction device, from the first to the second terminals of the phase winding and through said first unidirectional conduction device to the first terminal of the voltage bus, after which the phase winding current begins to decrease;
- wherein the phase winding current changes between the first and second predetermined values until the inductance between the rotor and stator poles reaches a minimum value.
An apparatus for controlling a switched reluctance machine, wherein the switched reluctance machine includes a plurality of rotor and stator poles and a plurality of phase windings on one or more of the stator poles, and wherein the switched reluctance machine is responsive to a voltage bus, said apparatus comprising:
- for each phase winding:
- a first switch connected between a first terminal of the voltage bus and a first terminal of the phase winding;
- a second switch connected between a second terminal of the voltage bus and a second terminal of the phase winding;
- a first unidirectional conduction device having a first terminal connected to the first terminal of the voltage bus and a second terminal connected to the second terminal of the phase winding, wherein said first unidirectional conduction device conducts current only in the direction from the first to the second terminal thereof;
- a second unidirectional conduction device having a first terminal connected to the first terminal of the phase winding and a second terminal connected to the second terminal of the voltage bus, wherein said second unidirectional conduction device conducts current only in the direction from the first terminal to the second terminal thereof;
- wherein during at least a portion of the time when the rotor and stator poles are approaching, each of said first and second switches are closed and current flows from the second terminal of the voltage bus through the serial connection of said second switch, the phase winding and said first switch;
- wherein when the phase winding current is at a first predetermined value while the inductance of the rotor and stator poles of the phase winding is decreasing, opening said first and second switches, such that current flows from the first terminal of the voltage bus serially through said first unidirectional conduction device, from the second to the first terminals of the phase winding and through said second unidirectional conduction device to the second terminal of the voltage bus, after which the phase winding current begins to decrease;
- wherein when the phase winding current is at a second predetermined value, closing said first switch such that current flows through a short circuit loop comprising said first switch, the phase winding and said first unidirectional conduction device, after which the phase winding current begins to increase;
- wherein when the phase winding current is at the first predetermined value, opening said first switch such that the current flows from the first terminal of the voltage bus serially through said first unidirectional conduction device, from the second to the first terminals of the phase winding and through said second unidirectional conduction device to the second terminal of the voltage bus, after which the phase winding current begins to decrease;
- wherein the phase winding current changes between the first and second predetermined values until the inductance between the rotor and stator poles reaches a minimum value.
An apparatus for controlling the phase winding current of a switched reluctance machine, wherein the switched reluctance machine includes a plurality of rotor and stator poles and a plurality of phase windings on one or more of the stator poles, said apparatus comprising:
- a power converter connected to a bus, wherein the power converter supplies current to the plurality of phase windings from the bus;
- wherein the power converter reverses the voltage applied to each one of the plurality of phase windings when the current through the phase winding reaches a first predetermined value while the inductance between the rotor and stator poles of the phase winding is decreasing;
- and
- wherein said power converter shorts each one of the plurality of phase windings when the current through the phase winding reaches a second predetermined value while the inductance between the rotor and stator poles of the phase winding is decreasing.
Dependencies are inferred from the claim text.