FR3051295A1 - ROTATING ELECTRIC MACHINE WITH INCREASED POWER - Google Patents

Abstract

The invention relates mainly to a rotating electric machine for a motor vehicle, in particular of hybrid type, operating at a voltage of less than 60 volts comprising: - a stator having a body provided with notches and a multiphase winding (25) formed by a plurality coil (27) inserted into said slots, - characterized in that said rotary electric machine comprises twelve bridge arms (P1-P12) each formed by two electrically-controlled switches (31), said bridge arms (P1-P12) connected said coils (27) being controlled by a control module (30).

Description

ROTATING ELECTRICAL MACHINE WITH INCREASED POWER

The present invention relates to a rotating electric machine with increased power. The invention finds a particularly advantageous application with low voltage electrical machines, that is to say with electrical machines operating at a voltage of less than 60 volts. The electric machine is intended to be used in a motor vehicle, in particular of the hybrid type.

In known manner, the rotating electrical machines comprise a stator and a rotor secured to a shaft. The rotor may be integral with a driving shaft and / or driven and may belong to a rotating electrical machine in the form of an alternator, an electric motor, or a reversible machine that can operate in both modes.

The rotor comprises a body formed by a stack of sheets of sheet metal held in pack form by means of a suitable fastening system. The rotor comprises poles formed for example by permanent magnets housed in cavities formed in the body.

The stator is mounted in a housing configured to rotate the shaft through bearings. The stator includes a body having a plurality of teeth defining notches, and a coil inserted into the stator slots. The winding is obtained for example from enamel coated continuous son or from conductive elements in the form of pins joined together by welding. Alternatively, the phases of the machine are formed from individual coils each wrapped around a stator tooth.

In order to control the rotating electrical machine, a control module interacting with the engine control computer is connected to bridge arms. These bridge arms integrate rectifying elements generally taking the form of MOS transistors connected to the different phases of the machine. The control of the bridge arms is carried out in particular according to the stator temperature, the position and the speed of the rotor, as well as operating parameters of the engine returned by the engine computer. The bridge arms can operate in inverter mode or in voltage rectifier mode.

Conventionally, the power of a low-voltage electrical machine powered by the battery of a motor vehicle is of the order of 15kW. In order to increase this power, it is known to resize the bridge arms to be able to withstand the increase in the intensity of the current flowing in the machine. However, this poses cost problems related to the development of specific modules as well as problems of integration of the electronic block due to their large size. The invention aims to remedy these drawbacks effectively by proposing a rotating electrical machine for a motor vehicle, in particular of the hybrid type, operating at a voltage of less than 60 volts, comprising: a stator having a body provided with notches and a polyphase winding formed by a plurality of coils inserted into said slots, characterized in that said rotating electrical machine comprises twelve bridge arms each formed by two electrically controlled switches, said bridge arms connected to said coils being controlled by a control module. The invention thus makes it possible, by increasing the number of bridge arms with respect to a conventional configuration, to facilitate the integration of the system while allowing the electric machine to withstand the increase in the intensity of the current connected to the system. increase its power. The invention is also of economic interest by allowing the use of standard bridge arms facilitating the manufacture and maintenance of the electric machine.

In one embodiment, each notch contains coils associated with two different bridge arms.

According to one embodiment, said winding is a three-phase winding of concentrated type.

In one embodiment, each bridge arm is associated with a quarter phase.

According to one embodiment, the number of notches per pole and per phase is equal to 0.5.

According to one embodiment, said rotating electrical machine comprises 4 pairs of poles and a 12-tooth stator body.

In one embodiment, said rotating electrical machine has 8 pairs of poles and a 24-tooth stator body.

In one embodiment, said rotating electrical machine has 12 pairs of poles and a 36-tooth stator body.

According to one embodiment, said winding is of corrugated type and consists of two three-phase systems.

According to one embodiment, said two three-phase systems are offset from each other by an electrical angle between 0 and 60 degrees excluded.

In one embodiment, each bridge arm is associated with a half-phase.

According to one embodiment, each phase portion is constituted by a set of coils electrically connected in series or in parallel.

In one embodiment, the phases are coupled in a triangle or a star.

In one embodiment, a length of said stator body is greater than half of an outer radius of said stator body.

According to one embodiment, said rotating electrical machine is of the synchronous type.

In one embodiment, said rotating electrical machine comprises a rotor with permanent magnets. The invention will be better understood on reading the description which follows and the examination of the figures which accompany it. These figures are given for illustrative but not limiting of the invention.

Figure 1 shows a partial sectional view of a rotary electric machine according to the present invention with concentrated winding;

Figure 2 is a schematic representation of an exemplary embodiment of a bridge arm used in the rotating electrical machine according to the present invention;

FIG. 3 shows a circuit diagram of a three-phase winding of concentrated type according to the invention;

FIG. 4 shows an electrical diagram of a winding formed of two three-phase systems of corrugated type according to the invention;

Figure 5 is a schematic sectional representation of a portion of a corrugated winding of the rotating electrical machine according to the invention.

Identical, similar or similar elements retain the same reference from one figure to another.

FIG. 1 shows a rotating electrical machine 10 comprising an X-axis rotor 11 intended to be mounted on a shaft 12. A polyphase wound stator 15 surrounds the rotor 11 with the presence of an air gap between the outer periphery of the rotor 11 and the internal periphery of the stator 15. This stator 15 is fixed on a housing (not shown) configured to rotate the shaft 12 via ball bearings and / or needle. Advantageously, the rotating electrical machine 10 is of the synchronous type and has a power of between 25 and 30 kW.

More specifically, the rotor 11 comprises a body 16 formed by an axial stack of plane sheets in order to reduce the eddy currents. The rotor body 16 is made of ferromagnetic material. The rotor 11 has cavities 17 for receiving permanent magnets 18 forming magnetic poles.

The magnets 18 are preferably made of ferrite. Alternatively, the magnets 18 may however be made of rare earth depending on the applications and the desired power of the machine 10. Alternatively, the magnets 18 may be of different shade to reduce costs. For example, in each cavity 17, there is associated a ferrite magnet 18 and a rare earth magnet 18 more powerful but more expensive. Some cavities 17 may also be left empty depending on the desired power of the machine. The rotor 11 may be at flux concentration, that is to say that the lateral faces vis-à-vis the magnets 18 located in two consecutive cavities 17 are of the same polarity.

Moreover, the stator 15 comprises a body 21 and a coil 25. The stator body 21 consists of an axial stack of flat sheets. The stator body 21 has teeth 22 distributed angularly in a regular manner on an inner periphery of a yoke 24. These teeth 22 delimit notches 23, so that each notch 23 is delimited by two successive teeth 22. The notches 23 open axially into the axial end faces of the stator body 21. The notches 23 are also open radially inwardly of the stator body 21. The stator 15 may be provided with tooth roots 26 at the ends Free of teeth 22. Each tooth root 26 extends circumferentially on either side of a corresponding tooth. The rotating electrical machine 10 preferably has an elongate configuration, ie a length of the stator body 21 is greater than half the outer radius of said stator body 21.

To obtain a concentrated type winding, several phases A, B, C are formed by coils 27 each wound around a tooth 22. Each coil 27 is formed from an electrically conductive wire covered with a layer of electrically insulating material such as enamel. In an exemplary embodiment, a coil insulator may be interposed between each coil and the corresponding tooth.

Advantageously, the number of notches per pole and per phase is equal to 0.5 (or spp = 0.5 for "Slot per pole per phase"). Thus, as shown in FIG. 3, for a three-phase electrical machine with 4 pairs of poles, the stator body 21 has 12 teeth and therefore 12 coils referenced 27. According to the invention, each coil 27 is associated with a P1-P12 bridge arm formed of two controlled switches 31. The bridge arms P1-P12 connected to the coils 27 are controlled by a control module 30. As illustrated in Figure 2, each switch 31 may be constituted by a power transistor, for example of the MOS type, preferably associated with a freewheeling diode 32.

The supply voltage corresponding to the battery voltage Batt is between 48Volts and 52Volts.

Thus, for phase A, each coil 27 is associated with a bridge arm P1-P4. For phase B, each coil 27 is associated with a bridge arm P5-P8. For phase C, each coil 27 is associated with a bridge arm P9-P12.

Alternatively, for a three-phase electrical machine with 8 pairs of poles, the stator body 21 has 24 teeth, and therefore 24 coils. Two coils are then associated with each bridge arm P1-P12. For ease of understanding, only the additional spool 27 'associated with the arm P1 is represented by dashed lines, but the assembly with two parallel spools 27 and 27' is valid for all the bridge arms P1-P12.

Alternatively, for a three-phase electrical machine with 12 pairs of poles, the stator body 21 has 36 teeth and therefore 36 coils. Three coils are then associated with each bridge arm P1-P12. For ease of understanding, only the additional coils 27 ', 27 "associated with the arm P1 are shown in dotted line, but the assembly with three parallel coils 27, 27', 27" is valid for all the bridge arms P1- P12.

In all cases, each bridge arm P1-P12 is associated with a quarter phase.

The three phases A, B, C are star-coupled by being electrically connected to a neutral point N. As a variant, the phases A, B, C may be coupled in a triangle.

In the embodiment of FIGS. 4 and 5, the winding 25 is of corrugated type and consists of two three-phase systems A1, B1, C1 and A2, B2, C2. The two three-phase systems A1, B1, C1 and A2, B2, C2 are offset from each other by an electrical angle advantageously comprised between 0 and 60 degrees excluded. The winding 25 of each three-phase system A1, B1, C1 and A2, B2, C2 may be made from a continuous wire forming corrugations inside the slots 23 of the stator 15 or from pins electrically connected between they by welding.

Each bridge arm P1-P12 is then associated with a half-phase consisting of a set of coils 27 electrically connected in series or in parallel. In the case of a star coupling, the two three-phase systems A1, B1, C1 and A2, B2, C2 have distinct neutral points N1, N2 without an electrical connection between these neutral points N1, N2. As a variant, the two three-phase systems A1, B1, C1 and A2, B2, C2 may be coupled in a triangle.

It should be noted that in all the embodiments, each notch 23 contains coils 27 associated with two different bridge arms P1-P12. Indeed, for the concentrated winding 25, each notch 23 contains two half-coils 27 implanted in the same notch. In the case of a corrugated winding made from a continuous wire or pin as shown in FIG. 5, each notch 23 may comprise, for example, coils 27 associated with two half-phases. The hatched conductors 33 forming a coil thus belong to the same half-phase, while the conductors 33 'forming another coil belong to another half-phase. The same notch 23 may contain half-phases of the same phase or half-phases of different phases.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention which would not be overcome by replacing the different elements by any other equivalent.

In addition, the various features, variations, and / or embodiments of the present invention may be associated with each other in various combinations, to the extent that they are not incompatible or exclusive of each other.

Claims (16)

1. A rotating electric machine (10) for a motor vehicle, in particular of hybrid type, operating at a voltage of less than 60 volts comprising: - a stator (15) having a body (21) provided with notches (23) and a winding ( 25) polyphase formed by a plurality of coils (27) inserted in said notches (23), characterized in that said rotary electrical machine (10) comprises twelve bridge arms (P1-P12) each formed by two switches (31) controlled electrically, said bridge arms (P1-P12) connected to said coils (27) being controlled by a control module (30). 2. A rotary electric machine according to claim 1, characterized in that each notch (23) contains coils (27) associated with two different bridge arms (P1-P12). 3. Rotating electrical machine according to claim 1 or 2, characterized in that said coil (25) is a three-phase winding concentrated type. 4. A rotary electric machine according to claim 3, characterized in that each bridge arm (P1-P12) is associated with a quarter phase. 5. Rotating electrical machine according to claim 3 or 4, characterized in that the number of notches per pole and per phase (spp) is equal to 0.5. 6. Rotating electrical machine according to claim 5, characterized in that it comprises 4 pairs of poles and a stator body (21) with 12 teeth. 7. rotary electric machine according to claim 5, characterized in that it comprises 8 pairs of poles and a stator body (21) 24 teeth. 8. rotary electric machine according to claim 5, characterized in that it comprises 12 pairs of poles and a stator body (21) with 36 teeth. 9. A rotary electric machine according to claim 1 or 2, characterized in that said winding (25) is of corrugated type and consists of two three-phase systems (A1, B1, C1; A2, B2, C2). 10. A rotary electric machine according to claim 9, characterized in that said two three-phase systems (A1, B1, C1, A2, B2, C2) are offset from each other by an electrical angle (a) between 0 and 60 degrees excluded . 11. A rotary electric machine according to claim 9 or 10, characterized in that each bridge arm (P1-P12) is associated with a half-phase. 12. A rotary electric machine according to claim 4 or 11, characterized in that each phase portion is constituted by a set of coils (27) electrically connected in series or in parallel. 13. A rotary electric machine according to any one of claims 1 to 12, characterized in that the phases are coupled in a triangle or star. 14. A rotary electric machine according to any one of claims 1 to 13, characterized in that a length of said stator body (21) is greater than half of an outer radius of said stator body (21). 15. Rotating electrical machine according to any one of claims 1 to 14, characterized in that it is synchronous type. Rotary electric machine according to any one of claims 1 to 15, characterized in that it comprises a rotor (11) with permanent magnets (18).