Dual redundant variable field permanent magnet dynamoelectric machine

The present application relates to a dynamoelectric machine, and more particularly to a dual redundant permanent magnet dynamoelectric machine with independent deactivation.

Electric motor driven aircraft fuel pumps are prime reliable devices. If the fuel pump ceases operation, the aircraft engine will shut-down. For this reason, electric motor driven fuel pumps typically include two separate electric motors which power a common rotor assembly to provide redundant rotational power.

Historically, aircraft fuel pumps have not taken advantage of the compactness, light weight, and high efficiency of permanent magnet motors because one of the motors which power the common rotor assembly cannot be independently shut down.

A dual redundant permanent magnet type dynamoelectric machine according to an exemplary aspect of the present application includes a dual flux throttle system to selectively disable one of a first motor and a second motor.

A dual redundant permanent magnet type dynamoelectric machine according to an exemplary aspect of the present application includes a common drive shaft which is powered by a first motor and a second motor and a dual flux throttle system to selectively disable one of the first motor and the second motor in response to a detected condition while the common drive shaft continues to rotate.

A method of operating a dual redundant permanent magnet type dynamoelectric machine includes axially positioning a dual flux throttle system operable to selectively disable one of a first motor and a second motor in response to a detected condition while a common drive shaft continues rotating by the other of the first motor and the second motor.

Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiment. The drawings that accompany the detailed description can be briefly described as follows:

FIG. 1 is a general schematic block diagram of an energy conversion device (ECD) and an associated fuel system;

FIG. 2A is a sectional view of a dynamoelectric machine taken along a spring system;

FIG. 2B is a sectional view of a dynamoelectric machine of FIG. 2A taken along a piston system;

FIG. 2C is a schematic block diagram of an active control system for the dynamoelectric machine;

FIG. 3A is a sectional view of the dynamoelectric machine taken along a spring system with both motors in operation;

FIG. 3B is a sectional view of the dynamoelectric machine of FIG. 3A taken along a piston system;

FIG. 4A is a sectional view of a dynamoelectric machine taken along a spring system with the first motor disabled and the second motor operational;

FIG. 4B is a sectional view of the dynamoelectric machine of FIG. 4A taken along a piston system;

FIG. 5A is a sectional view of a dynamoelectric machine taken along a spring system with the first motor operational and the second motor disabled; and

FIG. 5B is a sectional view of the dynamoelectric machine of FIG. 5A taken along a piston system.

FIG. 1 illustrates a general schematic view of a fuel system 10 for an energy conversion device (ECD) 12 . A fuel pump 14 communicates fuel F from a reservoir 16 such as a fuel tank to the ECD 12 . The fuel F is typically a hydrocarbon such as jet fuel. One form of the ECD 12 is a gas turbine engine, and particularly such engines in aircraft.

FIG. 2A schematically illustrates a dual redundant permanent magnet type dynamoelectric machine 20 operable to power the fuel pump 14 . It should be understood that although the dynamoelectric machine 20 is utilized to drive the fuel pump 14 in the disclosed embodiment, the dynamoelectric machine 20 may be utilized in various systems to perform various operations.

The dynamoelectric machine 20 includes a housing 22 that mounts a set of bearings 24 A, 24 B which supports a drive shaft 26 that rotates about an axis of rotation X. The dynamoelectric machine 20 illustrated in the disclosed non-limiting embodiment is of the standard type. It should be understood that other types may alternatively benefit herefrom.

The housing 22 contains a dual stator assembly 28 which has a plurality of stator poles 30 A, 30 B. Each plurality of stator poles 30 A, 30 B is of a generally cylindrical pattern which face radially inward toward the axis of rotation X. It should be understood that other shapes, such as conical or stepped, may alternatively be utilized.

A dual rotor assembly 32 is mounted to the drive shaft 26 adjacent and in general alignment with the dual stator assembly 28 . The dual rotor assembly 32 includes a rotor hub 34 A, 34 B that mounts a first and second plurality of permanent rotor magnets 36 A, 36 B. In one non-limiting embodiment, the rotor hubs 34 A, 34 B are formed by the drive shaft 26 . The first and second plurality of permanent rotor magnets 36 A, 36 B are in a generally cylindrical pattern facing radially outward from the axis of rotation X toward the respective first and second plurality of stator poles 30 A, 30 B to define a first motor 38 A and a second motor 38 B which drive the common drive shaft 26 .

The dynamoelectric machine 20 further includes a dual flux throttle system 40 which has a first flux throttle system 40 A for the first motor 38 A and a second flux throttle system 40 B for the second motor 38 B. The first flux throttle system 40 A includes a first ring 42 Aa and a second ring 42 Ab radially located between the respective first plurality of stator poles 30 A and the first plurality of permanent rotor magnets 36 A. The second flux throttle system 40 B includes a first ring 42 Ba and a second ring 42 Bb radially located between the respective second plurality of stator poles 30 B and the second plurality of permanent rotor magnets 36 B.

The rings 42 Aa, 42 Ab, 42 Ba, 42 Bb are manufactured of a metallic material and rotate with the rotor assembly 32 . The rings 42 Aa, 42 Ab and the rings 42 Ba, 42 Bb are axially positioned along the axis of rotation X. The dual flux throttle system 40 independently controls the effective stack length of the first motor 38 A and the second motor 38 B through the independent axial insertion of the rings 42 Aa, 42 Ab between the first plurality of stator poles 30 A and the first plurality of permanent rotor magnets 36 A and the rings 42 Ba, 42 Bb second plurality of stator poles 30 B and the second plurality of permanent rotor magnets 36 B.

The dual flux throttle system 40 allows the first motor 38 A and the second motor 38 B to be independently de-activated without the need to stop the dual rotor assembly 32 . That is, one the first motor 38 A or the second motor 38 B may be shut-down, yet the other of the first motor 38 A and the second motor 38 B will continue to power the dual rotator assembly 26 and thus power the drive shaft 26 . By covering the plurality of permanent rotor magnets 36 A, 36 B, the magnetic flux fields from the covered magnets are short circuited to adjacent magnets. With the magnetic flux field short circuited, the rotor flux cannot impinge on the respective stator polls 30 A, 30 B such that the voltage in the respective plurality of stator poles 30 A, 30 B drops to zero.

In the event of a stator winding short circuit condition, the related rings 42 Aa, 42 Ab or rings 42 Ba, 42 Bb are axially positioned between the respective plurality of permanent rotor magnets 36 A, 36 B and stator poles 30 A, 30 B to effectively eliminate the magnetically induced voltage that may otherwise continue to feed the short circuit. Redundant operation is thereby provided without the potential to feed the short circuit.

A spring system 60 A, 60 B mounted within each rotor hub 34 A, 34 B axially biases the rings 42 Aa, 42 Ab and rings 42 Ba, 42 Bb to an outboard position. That is, the respective spring system 60 Aa, 60 Ab provides an outboard bias to the rings 42 Aa, 42 Ab and spring systems 60 Ba, 60 Bb provides an outboard bias to the rings 42 Ba, 42 Bb to provide normal operation. The spring systems 60 A, 60 B are generally arranged around the axis of rotation X and generally parallel thereto. It should be understood that other bias directions may alternatively be provided.

Referring to FIG. 2B , piston 58 Aa drives ring 42 Aa to overcome the spring system 60 Aa ( FIG. 2A ), piston 58 Ab drives ring 42 Ab to overcome the spring system 60 Ab ( FIG. 2A ), piston 58 Ba drives ring 42 Ba to overcome the spring system 60 Ba ( FIG. 2A ), and piston 58 Bb drives ring 42 Bba to overcome the spring system 60 Bb ( FIG. 2A ). Pistons 58 Aa, 58 Ab and pistons 58 Ba, 58 Bb operate in concert to overcome the respective spring systems 60 Aa, 60 Ab, and 60 Ba, 60 Bb to close the first flux throttle system 40 A over the first motor 38 A and the second flux throttle system 40 B over the second motor 38 B in response to the active control system 50 . Although only a single piston system 56 A, 56 B formed in each rotor hub 34 A, 34 B is illustrated for the respective first ring 42 A and second ring 42 B, it should be understood that the piston system 56 A, 56 B may include any number of pistons 58 Aa, 58 Ab and 58 Ba and 58 Bb to operate each flux throttle system 40 A, 40 B.

An active control system 50 which may generally include a servo-valve 52 A, 52 B operates the dual flux throttle system 40 in response to a controller 54 . The active control system 50 controls flow of a fluid such as lubricant from a lubricant system L (illustrated schematically) to axially position the rings 42 Aa, 42 Ab and rings 42 Ba, 42 Bb though the piston system 56 A, 56 B formed in each rotor hub 34 A, 34 B. The piston systems 56 A, 56 B include pistons 58 Aa, 58 Ab and 58 Ba and 58 Bb that are generally arranged around the axis of rotation X and generally parallel thereto ( FIG. 2 ).

The active control system 50 may be powered by the lubricant system L to communicate fluid to the servo-valve 52 A, 52 B for selective communication to the respective piston systems 56 A, 56 B for operation of the first flux throttle system 40 A of the first motor 38 A and the second flux throttle system 40 B of the second motor 38 B. Fluid is communicated to the piston system 56 A through a control port 70 which communicates with the drive shaft 26 though a housing passages 72 ( FIG. 2A ). From the drive shaft 26 fluid is communicated through radial passages 74 A, 74 B to communicate fluid into piston passages 76 A, 76 B and drive pistons 58 Aa, 58 Ab therein. Each piston 58 Aa, 58 Ab is connected to the respective first ring 42 Aa and the second ring 42 Ab for operation of the first flux throttle system 40 A to selectively drive the first ring 42 Aa and the second ring 42 Ab inboard toward each other. The drive shaft 26 is separated into a first chamber 26 A and a second chamber 26 B by a wall 27 such that the drive shaft 26 may be used to communicate fluid into the respective piston systems 56 A, 56 B. The drive shaft segments 26 A, 26 B are retained together by a fastener 26 F which may be hollow to communicate lubricant therethrough.

Fluid is communicated to the piston system 56 B through a control port 80 which communicates with the drive shaft 26 though a housing passages 82 . From the drive shaft 26 fluid is communicated through radial passages 84 A, 84 B to communicate fluid into piston passages 86 A, 86 B and drive pistons 58 Ba, 58 Bb therein. Each piston 58 Ba, 58 Bb is connected to the respective first ring 42 Ba and the second ring 42 Bb for operation of the second flux throttle system 40 B to drive the first ring 42 Ba and the second ring 42 Bb inboard toward each other.

FIGS. 3-5 illustrate example operational positions of the dual flux throttle system 40 of the dynamoelectric machine 20 . FIGS. 3A and 3B illustrate the dual flux throttle system 40 with both motors 38 A, 38 B in operation. FIGS. 4A and 4B illustrate the dual flux throttle system 40 with the first motor 38 A disabled and the second motor 38 B operational. FIGS. 5A and 5B illustrate the dual flux throttle system 40 with the first motor 38 A operational and the second motor 38 B disabled.

It should be noted that that the controller 54 ( FIG. 2C ) may be utilized to selectively control the dual flux throttle system 40 to shut-down either the first motor 38 A or the second motor 38 B in the event of a predetermined or sensed condition such as a stator winding short circuit condition. The controller 54 may also implement other functionality such as partial axial movement to control back EMF voltage through partial movement of the first flux throttle system 40 A for the first motor 38 A and/or the second flux throttle system 40 B for the second motor 38 B.

It should be understood that the dual flux throttle system 40 may alternatively or additionally be actuated with an external actuator via a bearing and actuator arm such as a throwout bearing in a clutch system. The actuator may be, for example only, linear, rotary, hydraulic, ball screw, etc.

It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom.

The foregoing description is exemplary rather than defined by the limitations within. Various non-limiting embodiments are disclosed herein, however, one of ordinary skill in the art would recognize that various modifications and variations in light of the above teachings will fall within the scope of the appended claims. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described. For that reason the appended claims should be studied to determine true scope and content.