Aircraft comprising a synchronous reluctance machine

Abstract

The present invention relates to an aircraft with at least one synchronous reluctance machine which comprises a stator with a plurality of grooves and teeth and a rotor with a plurality of magnetic flux barriers, wherein at least one magnetic flux barrier is designed asymmetrical to the q-axis.

Claims

1. An aircraft with at least one synchronous reluctance machine, comprising: a stator with a plurality of grooves and teeth and a rotor with a plurality of magnetic flux barriers, wherein at least one magnetic flux barrier is asymmetrical to a q-axis of the rotor; wherein a first magnetic flux barrier of the plurality of magnetic flux barriers has a first end opposed to one of the plurality of grooves of the stator and an opposite end of a same or a second magnetic flux barrier opposed to one of the plurality of teeth of the stator; and wherein the first magnetic flux barrier and the second magnetic flux barrier together form a flux blocking portion; wherein flux barrier angles of the at least one magnetic flux barrier are defined by the following equations: $\begin{array}{cc}{}_{\mathrm{Stator}}=\frac{360}{N_{\mathrm{stator}\mathrm{groove}}}& \left(1\right)\\ {}_{1,\max }={}_{\mathrm{sym}}+{}_{\mathrm{Stator}}& \left(2\right)\\ {}_{2,\min }={}_{\mathrm{sym}}-{}_{\mathrm{Stator}}& \left(3\right)\\ {}_{\mathrm{Stator}}\frac{\left|{}_1-{}_2\right|}{2}& \left(4\right)\end{array}$ wherein .sub.1/2 are unequal flux barrier angles and .sub.1,max defines a maximum value for a first flux barrier angle, .sub.2,min defines a minimum value for a second flux barrier angle, .sub.sym represents a symmetrical reference angle, and .sub.stator represents a groove pitch of the stator.

2. The aircraft of claim 1, wherein the flux barrier angles of the at least one asymmetrical magnetic flux barrier are unequal.

3. The aircraft of claim 1, wherein at least one or more of an innermost magnetic flux barrier is asymmetrical to the q-axis.

4. The aircraft of claim 1, wherein the flux barrier angles of the at least one magnetic flux barrier are chosen such that a flux barrier end approximately is located over a stator groove and an opposite flux barrier end approximately is located over a stator tooth.

5. The aircraft of claim 1, wherein an arrangement of the magnetic flux barrier of a rotor cross-section is point-symmetrical to an axis of rotation of the rotor.

6. The aircraft of claim 5, wherein the arrangement of the magnetic flux barrier of the rotor cross-section is point-symmetrical to the axis of rotation of the rotor per magnetic pole.

7. The aircraft of claim 1, wherein the rotor is divided into one or more segments in an axial direction, wherein a part of the rotor segments is mounted on a rotor shaft folded about a Z-axis.

8. The aircraft of claim 7, wherein the one or more segments is even or not even.

9. The aircraft of claim 7, wherein the one or more segments comprise one or more laminations of a rotor package.

10. The aircraft of claim 9, wherein the rotor package is constructed of identical laminations, and wherein adjacent laminations are arranged on the rotor shaft folded by 180 with respect to the Z-axis.

11. The aircraft of claim 1, wherein the stator includes a plurality of regularly spaced grooves and teeth.

12. The aircraft of claim 1, wherein the at least one synchronous reluctance machine serves as a drive for at least one electric actuator.

13. The aircraft of claim 12, wherein the drive for the at least one electric actuator is a central drive for a high-lift system.

14. The aircraft of claim 12, wherein the drive for the at least one electric actuator is an electromechanical drive of a flight control system.

15. The aircraft of claim 12, wherein the drive for the at least one electric actuator is an electromechanical drive of a landing gear actuation system.

16. The aircraft of claim 12, wherein the drive for the at least one electric actuator is an electromechanical drive of a steering system.

17. An aircraft with at least one synchronous reluctance machine, comprising: a stator with a plurality of grooves and teeth and a rotor with a plurality of magnetic flux barriers, further comprising flux barrier angles, wherein at least one magnetic flux barrier is asymmetrical to a q-axis, wherein at least one or more of an innermost magnetic flux barrier is asymmetrical to the q-axis, wherein the flux barrier angles of the at least one magnetic flux barrier are such that a flux barrier end is located over a stator groove and an opposite flux barrier end is located over a stator tooth; and wherein a first end of the at least one magnetic flux barrier is thinner than a section of the at least one magnetic flux barrier proximate to a midpoint of the rotor; wherein the flux barrier angles of the at least one magnetic flux barrier are defined by the following equations: $\begin{array}{cc}{}_{\mathrm{Stator}}=\frac{360}{N_{\mathrm{stator}\mathrm{groove}}}& \left(1\right)\\ {}_{1,\max }={}_{\mathrm{sym}}+{}_{\mathrm{Stator}}& \left(2\right)\\ {}_{2,\min }={}_{\mathrm{sym}}-{}_{\mathrm{Stator}}& \left(3\right)\\ {}_{\mathrm{Stator}}\frac{\left|{}_1-{}_2\right|}{2}& \left(4\right)\end{array}$ wherein .sub.1/2 are unequal flux barrier angles and .sub.1,max defines a maximum value for a first flux barrier angle, .sub.2,min defines a minimum value for a second flux barrier angle, .sub.sym represents a symmetrical reference angle, and .sub.stator represents a groove pitch of the stator.

Description

BRIEF DESCRIPTION OF FIGURES

(1) FIG. 1 shows a representation of the barrier geometry proposed according to the prior art, in which two different barrier configurations are combined to a modified geometry.

(2) FIG. 2 shows a representation of the lamination according to the invention and of a folded lamination.

(3) FIG. 3 shows a top view and a side view of the rotor segments according to the present invention.

(4) FIG. 4 shows a top view of the rotor cross-section and stator construction with the indicated angle assignment of rotor flux barriers and stator tooth.

DETAILED DESCRIPTION

(5) In the following, the construction of the synchronous reluctance motor according to the invention will be set forth in detail, as it is used in an aircraft according to the present invention. The synchronous reluctance motor for example serves for controlling the flap kinematics of an airplane. In particular, the use of the motor in the electric PCU is to be considered, which represents the central drive unit of a high-lift system. However, other key applications also are conceivable, in particular for all electric actuators of the aircraft, such as for example electromechanical drives of the flight control as well as of the landing gear actuation (refraction and extension) or the steering system.

(6) FIG. 2 shows the construction of the rotor according to the invention in cross-section, wherein two laminations 1a, 1b are shown. The rotor 1 generally is stacked to form a sheet package of a plurality of electrical sheets 1a, 1b, wherein the individual electrical sheets have the structure shown in FIG. 2. In detail, the cross-section 1a, 1b of FIG. 2 shows a four-pole rotor construction with a total of four flux blocking portions, wherein each flux blocking portion includes two magnetic flux barriers 10, 11. The four flux blocking portions are identical, i.e. the flux barriers 10, 11 of the portions are identical in design, whereby a point symmetry of the rotor cross-section with respect to the axis of rotation 5 is obtained. In particular, it can be seen that the point symmetry is point-symmetrical to each opposite magnetic pole.

(7) The flux barriers 10, 11 themselves are designed asymmetrical, wherein the inequality of the respective magnetic flux barrier angles .sub.1/2 of a flux barrier 10, 11 and the resulting asymmetry to the q-axis can be recognized. Magnetic flux barrier angle .sub.1/2 is understood to be the angle taken by the outer ends 10a, 10b, 11a, 11b of a flux barrier 10, 11, in particular by the outer edge of the outer ends, with respect to the straight middle part of the flux barrier.

(8) For each magnetic flux barrier 10, 11 the chosen magnetic flux angle .sub.1/2 is reduced or increased with respect to a symmetrical barrier angle .sub.sym by a certain amount. Symmetrical barrier angle .sub.sym is understood to be an original starting or reference angle, which usually is taken by the outer ends of a symmetrical barrier with respect to the q-axis. In the case of a symmetrical barrier, the angle would be identical for both ends and preferably would be 135.

(9) Proceeding from this symmetrical reference angle .sub.sym, the angle .sub.2 of the one barrier end 10a, 11a is increased by a specific angle amount, while the angle .sub.1 of the opposite end 10b, 11b is reduced by a specific angle value. The angle changes for .sub.1/2 generally are not equal in amount, although this cannot be excluded.

(10) What is important is the position of flux barrier ends 10a, 10b of the innermost barrier 10, as the same have the largest opening angle and the smallest distance to the center of the rotor axis of rotation 5. FIG. 4 shows the position of the rotor 1 with respect to the stator 20. On the stator side, the end points 10a, 10b of the innermost barrier 10 cover a groove opening 21 with the one end point 10b and a stator tooth 22 with the other end point 10a. In FIG. 4, the opening angles .sub.1, .sub.2 of the flux barrier 10 are indicated.

(11) To fulfill this requirement, an admissible range must be found for the adaptation of the barrier angle changes. For this purpose, the following equations can be used:

(12) $\begin{array}{cc}{}_{\mathrm{Stator}}=\frac{360}{N_{\mathrm{stator}\mathrm{groove}}}& \left(1\right)\\ {}_{1,\max }={}_{\mathrm{sym}}+{}_{\mathrm{Stator}}& \left(2\right)\\ {}_{2,\min }={}_{\mathrm{sym}}-{}_{\mathrm{Stator}}& \left(3\right)\\ {}_{\mathrm{Stator}}\frac{\left|{}_1-{}_2\right|}{2}& \left(4\right)\end{array}$
wherein the angle .sub.Stator here represents the groove pitch of the stator 20. Thus, a maximum value .sub.1,max is defined for the barrier angle .sub.1, wherein .sub.1<.sub.1,max, and for the second barrier angle .sub.2 a minimum angle .sub.2,min is defined, wherein here .sub.2>.sub.2,min.

(13) Hence, the angle .sub.2 of an originally symmetrical barrier end 10a maximally should be reduced by the angle .sub.Stator, while at the same time the angle .sub.1 of the opposite end 10b maximally is increased by the angle .sub.Stator.

(14) For the chosen angle .sub.1, .sub.2 the following then applies:

(15) ${}_{\mathrm{Stator}}\frac{\left|{}_2-{}_1\right|}{2}$

(16) The representation of FIG. 4 furthermore clearly shows that the stator 20 is characterized by an arbitrary number of stator teeth 22 and stator grooves 21, wherein the distance between the individual grooves or teeth is constant over the stator circumference.

(17) For the further reduction of the torque ripple, the occurring harmonic flux components must cancel each other out. For this purpose, the rotor 1 additionally is divided into two or more segments A, B in axial direction, as can be taken for example from FIG. 3. The individual segments A, B can be characterized by one or more laminations 1a, 1b, wherein within a segment A, B the individual sheets are identical in design and are mounted on the rotor shaft with the same orientation. The segments A, B use identical laminations, but differ in their orientation on the rotor shaft.

(18) For example, segment A uses the laminations 1b in the illustrated orientation. When this lamination geometry is folded about the Z-axis by 180, the lamination geometry 1a is obtained, as it is shown in FIG. 2 and also in FIG. 3. All laminations of the segments B use the orientation on the shaft according to the representation 1a.

(19) The arrangement of the individual magnetic flux barriers 10, 11 has a point symmetry with respect to the axis of rotation 5, in contrast to the prior art. By the suitable choice of the flux barrier angles .sub.1/2, a precisely defined phase position of the torque ripple can be adjusted. In connection with a segmentation of the machine into n parts A, B, wherein n is an even number, and folding of the segment halves A, B against each other, the torque ripple can be reduced considerably. The torques of the individual segments A, B are added on the shaft and due to the superposition lead to a reduced ripple, i.e. by applying the sheet packages according to segments A, B onto the rotor shaft, the resulting overall torque is superimposed, and the ripple of the torque thereby is canceled out by the phase shift. Due to the asymmetrical design of the flux barrier angles .sub.1/2, the mean torque remains almost unchanged.

(20) FIG. 3 shows an arrangement A, B, A, B, so that respectively adjacent segments A, B are rotated by 180. Arbitrary configurations, however, are conceivable, such as for example ABBA, ABBAABBA or BAABBAAB. The present invention, however, by no means should be limited to a concrete configuration.