Tapped stator axial motor and drive for extended operating range

1 . A rotary energy conversion device, comprising:

an armature including at least a first winding segment and a second winding segment that are each configured to generate magnetic flux when energized, the second winding segment being connected in series with the first winding segment;

a first inverter circuit configured to energize both the first winding segment and the second winding segment during a first mode of operation of the rotary energy conversion device, the first inverter circuit including a first switch configured to selectively allow current to flow from a first voltage rail to a first tap for the first winding segment during the first mode of operation;

a second inverter circuit configured to energize the second winding segment but not the first winding segment during a second mode of operation of the rotary energy conversion device, the second inverter circuit including a second switch configured to selectively allow current to flow from a second voltage rail to a second tap for the second winding segment during the second mode of operation, wherein the second voltage rail is configured to be connected to a first terminal of a voltage source; and

a third switch configured and arranged to allow current originating from the voltage source to flow from the second voltage rail to the first voltage rail during the first mode of operation, and to prohibit flow of current from the first voltage rail to the second voltage rail during the second mode of operation.

2 . The rotary energy conversion device of claim 1 , wherein:

the first inverter circuit further includes a fourth switch configured to selectively allow current to flow from the first tap to a third voltage rail during the first mode of operation;

the second inverter circuit further includes a fifth switch configured to selectively allow current to flow from the second tap to a fourth voltage rail during the second mode of operation, wherein the fourth voltage rail is configured to be connected to a second terminal of the voltage source; and

the rotary energy conversion device further includes a sixth switch configured and arranged to allow current to flow from the third voltage rail to the fourth voltage rail during the first mode of operation, and to prohibit flow of current from the fourth voltage rail to the third voltage rail during the second mode of operation.

3 . The rotary energy conversion device of claim 2 , wherein:

the third switch includes a first diode including a first anode and a first cathode, the first anode being connected to the second voltage rail and the first cathode being connected to the first voltage rail; and

the sixth switch includes a second diode including a second anode and a second cathode, the second anode being connected to the third voltage rail and the second cathode being connected to the fourth voltage rail.

4 . The rotary energy conversion device of claim 3 , wherein:

the first diode is a first body diode of a first transistor including a first current terminal, a second current terminal, and a first control terminal, the first current terminal being connected to the second voltage rail, the second current terminal being connected to the first voltage rail, and the first control terminal being configured and arranged to be driven to allow current flow from the first current terminal to the second current terminal during the first mode of operation; and

the second diode is a second body diode of a second transistor including a third current terminal, a fourth current terminal, and a second control terminal, the third current terminal being connected to the third voltage rail, the fourth current terminal being connected to the fourth voltage rail, and the second control terminal being configured and arranged to be driven to allow current flow from the third current terminal to the fourth current terminal during the first mode of operation.

5 . The rotary energy conversion device of claim 2 , further comprising a controller coupled to the first inverter circuit and the second inverter circuit, the controller being configured to:

control at least the first switch and the fourth switch of the first inverter circuit to energize both the first winding segment and the second winding segment during the first mode of operation; and

control at least the second switch and the fifth switch of the second inverter circuit to energize the second winding segment but not the first winding segment during the second mode of operation.

6 . The rotary energy conversion device of claim 5 , wherein the controller is further configured to:

control the third switch to allow current originating from the voltage source to flow from the second voltage rail to the first voltage rail during the first mode of operation;

control the sixth switch to allow current to flow from the third voltage rail to the fourth voltage rail during the first mode of operation;

control the third switch to prohibit flow of current from the first voltage rail to the second voltage rail during the second mode of operation; and

control the sixth switch to prohibit flow of current from the fourth voltage rail to the third voltage rail during the second mode of operation.

7 . The rotary energy conversion device of claim 2 , further comprising:

a rotor including one or more permanent magnets configured and arranged to generate first magnetic flux within an active region of the rotary energy conversion device;

wherein:

the armature is included in a stator of the rotary energy conversion device;

the first winding segment and the second winding segment are configured and arranged to generate second magnetic flux within the active region when the first winding segment and the second winding segment are both energized by the first inverter circuit during the first mode of operation; and

the first winding segment is configured and arranged to generate third magnetic flux within the active region when the first winding segment is energized by the second inverter circuit during the second mode of operation.

8 . The rotary energy conversion device of claim 7 , wherein:

the one or more permanent magnets are configured and arranged to generate the first magnetic flux generally parallel to an axis of rotation of the rotor;

the first winding segment and the second winding segment are configured and arranged to generate the second magnetic flux generally parallel to the axis of rotation when the first winding segment and the second winding segment are both energized by the first inverter circuit during the first mode of operation; and

the first winding segment is configured and arranged to generate the third magnetic flux generally parallel to the axis of rotation when the first winding segment is energized by the second inverter circuit during the second mode of operation.

9 . The rotary energy conversion device of claim 8 , wherein the stator comprises a printed circuit board including conductive traces forming the first winding segment and the second winding segment.

10 . The rotary energy conversion device of claim 2 , wherein the armature comprises a printed circuit board including conductive traces forming the first winding segment and the second winding segment.

11 . The rotary energy conversion device of claim 2 , wherein:

the armature has a wye configuration in which windings for three phases of the armature are connected at a common point;

the first winding segment and the second winding segment are associated with a first phase of the three phases; and

an end of the second winding segment is connected to the common point.

12 . The rotary energy conversion device of claim 11 , wherein:

the armature further includes a third winding segment and a fourth winding segment associated with a second phase of the armature, and a fifth winding segment and a sixth winding segment associated with a third phase of the armature, the third winding segment being connected in series with the fourth winding segment, the fifth winding segment being connected in series with the sixth winding segment, and ends of the fourth winding segment and the sixth winding segment being connected to the common point;

the first inverter circuit is further configured to energize the third winding segment, the fourth winding segment, the fifth winding segment, and the sixth winding segment during the first mode of operation; and

the second inverter circuit is further configured to energize the fourth winding segment and the sixth winding segment, but not the third winding segment or the fifth winding segment during the second mode of operation.

13 . The rotary energy conversion device of claim 2 , wherein:

the armature has a delta configuration in which one or more first windings for a first phase are connected between the first tap and a third tap, one or more second windings for a second phase are connected between the third tap and a fourth tap, and one or more third windings for a third phase are connected between the fourth tap and the first tap;

the first winding segment and the second winding segment are included in the one or more first windings; and

the first inverter circuit is further configured to energize the one or more second windings and the one or more third windings during the first mode of operation.

14 . A method for operating a rotary energy conversion device comprising an armature including at least a first winding segment and a second winding segment that are each configured to generate magnetic flux when energized, the second winding segment being connected in series with the first winding segment, the method comprising:

operating a first inverter circuit, at least in part by controlling a first switch to selectively allow current to flow from a first voltage rail to a first tap for the first winding segment, to energize both the first winding segment and the second winding segment during a first mode of operation of the rotary energy conversion device;

operating a second inverter circuit, at least in part by controlling a second switch to selectively allow current to flow from a second voltage rail, which is connected to a first terminal of a voltage source, to a second tap for the second winding segment, to energize the second winding segment but not the first winding segment during a second mode of operation of the rotary energy conversion device; and

controlling a third switch to allow current originating from the voltage source to flow from the second voltage rail to the first voltage rail during the first mode of operation, and to prohibit flow of current from the first voltage rail to the second voltage rail during the second mode of operation.

15 . The method of claim 14 , wherein:

operating the first inverter circuit further includes controlling a fourth switch to selectively allow current to flow from the first tap to a third voltage rail during the first mode of operation;

operating the second inverter circuit further includes controlling a fifth switch to selectively allow current to flow from the second tap to a fourth voltage rail during the second mode of operation, wherein the fourth voltage rail is connected to a second terminal of the voltage source; and

the method further comprises controlling a sixth switch to allow current to flow from the third voltage rail to the fourth voltage rail during the first mode of operation, and to prohibit flow of current from the fourth voltage rail to the third voltage rail during the second mode of operation.

16 . The method of claim 15 , wherein:

the third switch includes a first diode including a first anode and a first cathode, the first anode being connected to the second voltage rail and the first cathode being connected to the first voltage rail; and

the sixth switch includes a second diode including a second anode and a second cathode, the second anode being connected to the third voltage rail and the second cathode being connected to the fourth voltage rail.

17 . The method of claim 16 , wherein:

the first diode is a first body diode of a first transistor including a first current terminal, a second current terminal, and a first control terminal, the first current terminal being connected to the second voltage rail, and the second current terminal being connected to the first voltage rail;

the second diode is a second body diode of a second transistor including a third current terminal, a fourth current terminal, and a second control terminal, the third current terminal being connected to the third voltage rail, and the fourth current terminal being connected to the fourth voltage rail; and

the method further comprises:

driving the first control terminal to allow current to flow from the first current terminal to the second current terminal during the first mode of operation; and

driving the second control terminal to allow current to flow from the third current terminal to the fourth current terminal during the first mode of operation.

18 . The method of claim 15 , wherein the rotary energy conversion device includes a controller, and the method further comprises using the controller to:

control at least the first switch and the fourth switch of the first inverter circuit to energize both the first winding segment and the second winding segment during the first mode of operation; and

control at least the second switch and the fifth switch of the second inverter circuit to energize the second winding segment but not the first winding segment during the second mode of operation.

19 . The method of claim 18 , further comprising using the controller to:

control the third switch to allow current originating from the voltage source to flow from the second voltage rail to the first voltage rail during the first mode of operation;

control the sixth switch to allow current to flow from the third voltage rail to the fourth voltage rail during the first mode of operation;

control the third switch to prohibit flow of current from the first voltage rail to the second voltage rail during the second mode of operation; and

control the sixth switch to prohibit flow of current from the fourth voltage rail to the third voltage rail during the second mode of operation.

20 . The method of claim 15 , wherein:

the rotary energy conversion device comprises a rotor including one or more permanent magnets configured and arranged to generate first magnetic flux within an active region of the rotary energy conversion device;

the armature is included in a stator of the rotary energy conversion device;

operating the first inverter circuit further includes using the first inverter circuit to energize the first winding segment and the second winding segment to generate second magnetic flux within the active region during the first mode of operation; and

operating the second inverter circuit further includes using the second inverter circuit to energize the first winding segment to generate third magnetic flux within the active region during the second mode of operation.

21 . The method of claim 20 , wherein:

the one or more permanent magnets are configured and arranged to generate the first magnetic flux generally parallel to an axis of rotation of the rotor;

operating the first inverter circuit further includes using the first inverter circuit to energize the first winding segment and the second winding segment to generate the second magnetic flux generally parallel to the axis of rotation during the first mode of operation; and

operating the second inverter circuit further includes using the second inverter circuit to energize the first winding segment to generate the third magnetic flux generally parallel to the axis of rotation during the second mode of operation.

22 . The method of claim 21 , wherein the stator comprises a printed circuit board including conductive traces forming the first winding segment and the second winding segment.

23 . The method of claim 15 , wherein the armature comprises a printed circuit board including conductive traces forming the first winding segment and the second winding segment.

24 . The method of claim 15 , wherein:

the armature has a wye configuration in which windings for three phases of the armature are connected at a common point;

the first winding segment and the second winding segment are associated with a first phase of the three phases; and

an end of the second winding segment is connected to the common point.

25 . The method of claim 24 , wherein:

the armature further includes a third winding segment and a fourth winding segment associated with a second phase of the armature, and a fifth winding segment and a sixth winding segment associated with a third phase of the armature, the third winding segment being connected in series with the fourth winding segment, the fifth winding segment being connected in series with the sixth winding segment, and ends of the fourth winding segment and the sixth winding segment being connected to the common point;

operating the first inverter circuit further includes using the first inverter circuit to energize the third winding segment, the fourth winding segment, the fifth winding segment, and the sixth winding segment during the first mode of operation; and

operating the second inverter circuit further includes using the second inverter circuit to energize the fourth winding segment and the sixth winding segment, but not the third winding segment or the fifth winding segment during the second mode of operation.

26 . The method of claim 15 , wherein:

the armature has a delta configuration in which one or more first windings for a first phase are connected between the first tap and a third tap, one or more second windings for a second phase are connected between the third tap and a fourth tap, and one or more third windings for a third phase are connected between the fourth tap and the first tap;

the first winding segment and the second winding segment are included in the one or more first windings; and

operating the first inverter circuit further includes using the first inverter circuit to energize the one or more second windings and the one or more third windings during the first mode of operation.

27 . A rotary energy conversion device, comprising:

an armature including at least a first winding segment and a second winding segment that are each configured to generate magnetic flux when energized, the second winding segment being connected in series with the first winding segment;

a first inverter circuit configured to energize both the first winding segment and the second winding segment during a first mode of operation of the rotary energy conversion device, the first inverter circuit including a first switch configured to selectively allow current to flow from a first tap for the first winding segment to first voltage rail during the first mode of operation;

a second inverter circuit configured to energize the second winding segment but not the first winding segment during a second mode of operation of the rotary energy conversion device, the second inverter circuit including a second switch configured to selectively allow current to flow from a second tap for the second winding segment to a second voltage rail during the second mode of operation, wherein the second voltage rail is configured to be connected to a terminal of a voltage source; and

a third switch configured and arranged to allow current to flow from the first voltage rail to the second voltage rail during the first mode of operation, and to prohibit flow of current from the second voltage rail to the first voltage rail during the second mode of operation.

28 . The rotary energy conversion device of claim 27 , further comprising a controller coupled to the first inverter circuit and the second inverter circuit, the controller being configured to:

control at least the first switch of the first inverter circuit to energize both the first winding segment and the second winding segment during the first mode of operation;

control at least the second switch of the second inverter circuit to energize the second winding segment but not the first winding segment during the second mode of operation;

control the third switch to allow current to flow from the first voltage rail to the second voltage rail during the first mode of operation; and

control the third switch to prohibit flow of current from the second voltage rail to the first voltage rail during the second mode of operation.