Dynamometer for a test stand for an aircraft turbomachine
The invention relates to a rotating electric machine, such as a dynamometer. The rotor of the machine comprises a circular row of resultant magnetic poles of which the polarity forms an alternation of opposed poles. The resultant poles each include a pair of permanent magnets in a “V”, each equipped with a north pole N, a south pole S, and opposed faces, where the magnet poles are located. In each resultant pole the magnets are disposed so as to have faces having identical polarities, which faces are oriented radially outwardly, facing towards one another, thus forming therebetween an angle β between 90° and 110°, which makes it possible to increase the efficiency. The invention also relates to a turbomachine test stand equipped with a dynamometer enabling a recovery of electrical energy. The invention also relates to a hybrid motor vehicle propelled by the rotating electric machine.
1. A rotating electric machine, said rotating electric machine comprising:
a stator; and
a rotor comprising a circular row of resultant magnetic poles of which the polarities form an alternation of opposed magnetic poles, each resultant magnetic pole comprising a pair of permanent magnets, each permanent magnet comprising two opposed faces and two opposed poles (N, S), each pole located on one of the opposed faces of the permanent magnet, wherein:
in each resultant magnetic pole the permanent magnets are disposed so as to have mechanical faces having poles (N, S) of identical polarities oriented radially outwardly and facing towards one another, the combination of the identical poles determining the polarity of the resultant magnetic pole; and
in each resultant magnetic pole the outwardly oriented faces of the opposed faces of permanent magnets of identical polarities form, therebetween, a mechanical angle β between 95° and 105°.
2. The rotating electric machine in accordance with claim 1 , wherein the rotor comprises a stack of magnetic sheets in which the permanent magnets are inserted, and the rotor comprises eight resultant magnetic poles and sixteen permanent magnets.
3. The rotating electric machine in accordance with claim 1 , wherein the rotor forms a cylindrical body of which the outer surface has at least one dimples forming hydrodynamic dampers.
4. The rotating electric machine in accordance with claim 3 , wherein the dimples are arranged in at least one circular row of dimples.
5. The rotating electric machine in accordance with claim 3 , wherein at least one dimple comprises a profile, in a plane perpendicular to the axis of rotation, with a portion generally tangential to the outer surface of the rotor, and a portion mainly extending radially.
6. The rotating electric machine in accordance with claim 3 , wherein the dimples are disposed circumferentially between the resultant magnetic poles of the rotor.
7. The rotating electric machine in accordance with claim 3 , wherein a radial depth of at least one dimple is between 0.1 mm and 10 mm.
8. The rotating electric machine in accordance with claim 1 , wherein the rotor comprises a first set of axial cooling channels disposed between the permanent magnets of each resultant magnetic pole, the first channels being placed in an annular zone delimited radially by the radial height of the permanent magnets.
9. The rotating electric machine in accordance with claim 8 , wherein the first cooling channels are cylindrical, and a distance D 1 between the outer surface of the rotor and each first cooling channel is at least greater than a distance D 2 between each first cooling channel and each associated permanent magnet, the diameter of the first cooling channels being less than the width of the outwardly oriented faces of permanent magnets having resultant magnetic poles of identical polarities.
10. The rotating electric machine in accordance with claim 1 , wherein the rotor comprises axial cooling channels and a centrifugal fan with radial blades configured to drive a circulation of air through each axial cooling channel.
11. The rotating electric machine in accordance with claim 8 , wherein the rotor comprises a second set of axial cooling channels, an axis of rotation of the rotor being radially closer to the second channels than to the permanent magnets.
12. The rotating electric machine in accordance with claim 1 , wherein the permanent magnets occupy, angularly, at least a half of a circumference of the rotor.
13. A test stand for an engine with a rotating shaft, said test stand comprising:
a zone for receiving an engine to be tested; and
a dynamometer linked to the engine to be tested, wherein the dynamometer includes a rotating electric machine, the rotating electric machine comprises:
a stator; and
a rotor intended to be driven by the engine's rotating shaft, the rotor comprising a circular row of resultant magnetic poles of which the polarities form an alternation of opposed magnetic poles, each resultant magnetic pole comprising a pair of permanent magnets, each permanent magnet comprising two opposed faces and two opposed poles (N, S), each pole located on one of the opposed faces of the permanent magnet, wherein:
in each resultant magnetic pole the permanent magnets are disposed so as to have opposed faces having poles (N, S) of identical polarities oriented radially outwardly and facing towards one another, the combination of the magnetic poles determining the polarity of the resultant magnetic pole; and
in each resultant magnetic pole the outwardly oriented faces of the opposed faces of permanent magnets of identical polarities form, therebetween, a mechanical angle β equal to 100°, and the rotor comprises eight resultant magnetic poles.
14. The test stand in accordance with claim 13 , wherein the engine is a double flow turbofan engine.
15. The test stand in accordance with claim 13 , further comprising a control unit configured to control a resistive torque exerted by the dynamometer.
16. The test stand in accordance with claim 15 , further comprising a torque gauge connected to the dynamometer and connected to the control unit so as to measure the resistive torque that the dynamometer opposes to the turbomachine.
17. The test stand in accordance with claim 13 , further comprising a four-quadrant frequency converter connected to the dynamometer.
18. A motor vehicle, said vehicle comprising:
a rotating electric machine forming an electric motor configured to propel the vehicle, the rotating electric machine comprising:
a stator; and
a rotor comprising a circular row of resultant magnetic poles of which the polarities form an alternation of opposed magnetic poles, each resultant magnetic pole comprising a pair of permanent magnets, each permanent magnet comprising two opposed faces and two opposed poles (N, S) each pole located on one of the opposed faces of the permanent magnet, wherein:
in each resultant magnetic pole the permanent magnets are disposed so as to have faces having poles (N, S) of identical polarities oriented radially outwardly and facing towards one another, the combination of the identical poles determining the polarity of the resultant magnetic pole; and
in each resultant magnetic pole outwardly oriented faces of the opposed faces of permanent magnets of identical polarities form, therebetween, a mechanical angle β between 90° and 110°, and the rotor comprises a set of cylindrical axial cooling channels disposed between the permanent magnets of each resultant magnetic pole, and
a distance D 1 between the outer surface and each cylindrical axial cooling channel is at least greater than a distance D 2 between each cylindrical axial cooling channel and each associated permanent magnet.
19. The motor vehicle in accordance with claim 18 , further comprising a combustion engine and a battery connected to the rotating electric machine, the combustion engine being configured to propel the vehicle and to reload the battery, the electric machine being configured to recharge the battery.