WO2018115681A1

WO2018115681A1 - Rotating electrical machine for a motor vehicle

Info

Publication number: WO2018115681A1
Application number: PCT/FR2017/053649
Authority: WO
Inventors: Ludovic DOFFE; Cédric AGNERAY; Mostafa Kadiri; Benjamin Pouchelle; Matthieu MALLEVAEY
Original assignee: Valeo Equipements Electriques Moteur
Priority date: 2016-12-19
Filing date: 2017-12-18
Publication date: 2018-06-28
Also published as: FR3060899A1

Abstract

The invention relates mainly to a regulator module (47) intended, in particular, to regulate a field current injected into a field coil (B) of a rotor (12) of a rotating electrical machine, in particular for a motor vehicle, characterised in that it comprises a function (60) for limiting the maximum electric power of the rotating electrical machine (10).

Description

ROTATING ELECTRIC MACHINE FOR MOTOR VEHICLE

The present invention relates to a rotating electric machine for a motor vehicle. The invention finds a particularly advantageous, but not exclusive, application in the field of alternators and reversible electric machines for a motor vehicle. An alternator transforms mechanical energy into electrical energy. A reversible machine also makes it possible to convert electrical energy into mechanical energy, in particular to start the engine of the vehicle. In a manner known per se, an alternator comprises a housing and, inside thereof, a claw rotor mounted on a shaft and a stator which surrounds the rotor with the presence of an air gap. A pulley is attached to the front end of the shaft.

The stator comprises a sheet-shaped body with notches for mounting the stator winding. The coil comprises a plurality of phase windings which are, for example, three-phase windings connected in a star or in a triangle and whose outputs are connected to at least one electronic rectification module comprising rectifying elements, such as diodes or transistors. Furthermore, the rotor comprises two pole wheels and an excitation coil interposed axially between the two pole wheels. A regulator module makes it possible to regulate the excitation current injected into the excitation coil of the rotor.

The alternators have a maximum power depending on their electrotechnical design. A category is then defined to classify each machine according to this electrotechnical design. For example, the rated current supplied by the machine can be used as a criterion for classifying said machines.

Each rotating electrical machine is then fully dimensioned to fit into a category. Thus, a machine sized for a first category can not be used for a second category. In addition, a machine is generally oversized compared to the actual need for power demanded by the vehicle. This leads to a complete development of the machine according to its category and an increase in the cost of the machine. The invention aims to effectively overcome this disadvantage by proposing a regulator module intended in particular to regulate an excitation current injected into an excitation coil of a rotor of a rotating electrical machine, particularly for a motor vehicle, characterized in that it has a function of limiting a maximum electrical power of said rotating electrical machine.

The invention thus makes it possible to limit the power of a machine according to the desired category. This makes it possible both to use the same machine base for different categories by changing the maximum power level and to adapt this maximum power level according to the actual needs for the operation of the vehicle.

According to one embodiment, the limiting function is configured to limit a duty cycle of a voltage signal applied to the rotor excitation coil relative to a maximum duty cycle allowed by said rotating electrical machine. According to one embodiment, the limiting function is configured to adapt the duty cycle of the voltage signal applied to the rotor excitation coil according to a speed of the rotating electrical machine.

According to one embodiment, the limiting function is configured to adapt the duty cycle of the voltage signal applied to the rotor excitation coil according to a temperature of the rotating electrical machine.

According to one embodiment, the limitation function is able to return a relative duty cycle to a motor computer. In one embodiment, the relative duty cycle corresponds to a ratio between a real duty ratio provided by the regulator divided by a ratio cyclic maximum permissible by the rotating electrical machine.

According to one embodiment, the limitation function is able to return a signal relating to its activation state to a motor computer.

According to one embodiment, said regulator module comprises a memory storing a mapping establishing in particular a correspondence between speeds of the rotary electrical machine and associated cyclic ratios, said memory being able to be programmed according to the electrotechnical needs of said rotating electrical machine, in particular a speed desired current. The invention also relates to a rotary electrical machine characterized in that it comprises a regulator module as previously defined.

According to one embodiment, some components are undersized with respect to a power of active parts of said rotating electrical machine. This makes it possible both to size a base comprising the standard active parts and to size the components which do not constitute the active parts of said machine in a manner adapted to the category of the machine. Some dimensioning constraints associated with these components, such as thermal stress, are reduced since said components are dimensioned most accurately according to the actual power requirement. The costs of components that are no longer oversized and therefore the machine are reduced.

According to one embodiment, the undersized components are at least one of:

electronic components such as diodes or transistors of a rectifier bridge,

bearings for rotatably mounting a shaft of said rotating electrical machine,

an electrical isolation device for said machine,

a cooling device for said machine,

- an impregnating varnish,

a magnetic element such as a magnet of a rotor. For example, the electrical isolation device may be an insulator of a rotor coil and / or stator notch insulators and / or stator notch locks and / or an enamel covering the electrical conductors of the stator. the rotor coil and / or an enamel covering the electrical conductors of the stator winding.

For example, the cooling device may be a fan and / or a chamber comprising a coolant. In the case of a fan, the size of the fan adapted to the power of the vehicle allows a reduction of the noise generated by the fan.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given for illustrative but not limiting of the invention.

Figure 1 is a longitudinal sectional view of an alternator according to the present invention;

FIG. 2 is an electrical diagram of a regulator module according to the invention integrating a power limitation function;

Fig. 3 is a graphical representation illustrating the effect of the power limiting function on the current delivered by the rotating electrical machine at an ambient temperature of 25 degrees Celsius;

FIG. 4 is a representation of the evolution of the duty cycle as a function of the speed for different settings of the same rotating electrical machine;

FIG. 5 is a graphical representation of the evolution of the maximum duty cycle as a function of temperature for a given speed and a maximum reference duty cycle;

Fig. 6 is a block diagram illustrating the inputs and outputs of the power limiting function according to the present invention.

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

FIG. 1 shows a compact and polyphase alternator 10, in particular for a motor vehicle. This alternator 10 transforms mechanical energy into electrical energy and can be reversible. Such a reversible alternator 10, called an alternator / starter, makes it possible to convert electrical energy into mechanical energy, in particular to start the engine of the vehicle.

This alternator 10 comprises a casing January 1 and, inside thereof, a claw rotor 12 mounted on a shaft 13 of axis X, and a stator 16, which surrounds the rotor 12 with the presence of a gap 17. A pulley 14 is fixed on the shaft 13. This pulley belongs to a belt motion transmission device between the alternator 10 and the engine of the motor vehicle.

The stator 16 comprises a body 19 in the form of a pack of sheets provided with notches equipped with notch insulation for mounting the phases of the stator 16. Each phase comprises at least one winding passing through the notches of the body 19 of the stator 16 and forms, with all phases, a front bun 20 and a rear bun 21 on either side of the stator body 19.

The windings are obtained for example from a continuous wire covered with enamel or from bar-like conductor elements, such as pins connected together for example by welding. These windings are, for example, three-phase windings connected in a star or in a triangle, the outputs of which are connected to at least one rectifying bridge 22 comprising rectifying elements such as diodes or MOSFET transistors, especially when it comes to an alternator-starter as described for example in the document FR2745445.

The rotor 12 comprises two pole wheels 24, 25 each having a flange 28 of transverse orientation provided at its outer periphery with claws 29. The claws 29 of a wheel 24, 25 are directed axially towards the flange 28 of the other wheel . Each claw 29 of a pole wheel 24, 25 penetrates into the space between two claws 29 adjacent to the other pole wheel, so that the claws 29 of the pole wheels 24, 25 are interlocked with each other. one against the other. The outer periphery of the claws 29 defines with the inner periphery of the body 19 of the stator 16 the gap 17 between the stator 16 and the rotor 12.

A cylindrical core 30 is interposed axially between the flanges 28 of the wheels 24, 25. This core 30 carries at its outer periphery an excitation coil 31 wound in an insulator radially interposed between the core 30 and the coil 31.

In addition, the casing 1 1 comprises front 35 and rear 36 bearings assembled together. The bearings 35, 36 are of hollow shape and each carry a central bearing 37, 38 with balls for the rotational mounting of the shaft 13 of the rotor 12. The rear bearing 36 carries a brush holder 40 provided with brushes 41 for rubbing against rings 44 of a collector 45 connected by wire links to the excitation winding 31. The brushes 41 are electrically connected to a voltage regulator module 47. FIG. 2 shows such a regulator module 47 comprising a control circuit 48 for the current of the rotor 12. The circuit 48 applies a voltage switching control to the coil of B rotor excitation 12. The average rotor current 12 is proportional to the duty cycle of the control. A power stage 49 consists, for example, of a driving transistor T, typically of the MOS type, for switching and of a freewheeling diode D to allow the recirculation of the current of the coil B during the phases at the blocked state of the transistor T. Alternatively, the power stage 49 may consist of an H bridge known to those skilled in the art. The gate voltage of the transistor T is applied by a driver circuit 50 which guarantees a gate voltage sufficient to keep the transistor T passing.

A regulation circuit makes it possible to regulate the output voltage of the alternator 10. For this purpose, the regulation circuit comprises a linear servocontrol loop 52 and a pulse width modulator 53 which transforms the corrected error value. from the loop 52 to a cyclic ratio value of a signal applied at the input of the control circuit 50 of the transistor T. In this case, the control loop 52 comprises a comparator 54 ensuring the comparison between a voltage Vs measured in output of the alternator 10 and a set voltage Vcons, and a corrector 55, for example Proportional-Integral (PI) type.

In order to ensure its operation, the regulator module 47 comprises primary operating circuits, for example a supply circuit 56, a reference voltage circuit 57, and a clock circuit 58.

The regulator module 47 may also include protection systems against overvoltages and load shedding (not shown).

The limitation of the power of the alternator 10 is effected by means of a function 60 implemented in the chip of the regulator module 47, distinct from the regulation function intended to regulate the excitation current injected into the machine. This function 60 limits the maximum power of the machine to just the needs of the vehicle. The limitation function allows, more generally, to limit the output current supplied by the machine. Thus, as illustrated for example in FIG. 3, the limitation function 60 can adapt the performances of a machine of category 180A (see curve C1) to a machine of category 120A (see curve C2). This makes it possible to maintain a flow rate higher than the flow demanded by the on-board vehicle network while being as close as possible to this requested flow rate (see curve C3).

Clamping the electrical power of the machine makes it possible to undersize certain components with respect to a power of active parts constituted by the rotor 12 and the stator 16 of the electric machine. The undersized components may for example be the electronic components such as diodes or transistors of the rectifier bridge 22, and / or the bearings 37, 38 for the rotational mounting of the shaft 13, and / or notch closing wedges of the stator 16, and / or notch insulators of the stator 16, and / or the insulator of the rotor coil 12, and / or the enamel electrical conductors of the stator and / or that of the rotor coil, and / or the impregnating varnish, and / or the fans, and / or the cooling liquid, and / or the magnetic elements disposed on the rotor such as the magnets. The brush holder 40 may also be devoid of heat sink. This list of undersized components is not exhaustive, so the person skilled in the art will not depart from the scope of the invention by undersizing other components not mentioned above which are not part of the active parts of the invention. the rotating electric machine.

Preferably, in order to limit the flow rate of the alternator 10, the function 60 limits the duty cycle of the voltage signal applied to the excitation coil of the rotor 12 with respect to a maximum admissible duty cycle by the alternator 10. function 60 can be parameterized on the assembly line of the controller module 47 by programming it. These limitation parameters defined in more detail below are fixed in the memory 61 of the regulator module 47 and are not modifiable during the lifetime of the product. Each alternator 10 is thus protected by the limitation function 60 which makes it possible to guarantee the robustness of the product.

The limitation of the power of the alternator 10 can be adapted by the definition of several speed thresholds V_1, V_n associated with a duty ratio Df_1 -Df_n corresponding to the desired maximum power.

For example, as illustrated in FIG. 4, for a given generator set at 150A, a duty cycle Df_1 of 91% associated with a low speed threshold V_1 of 1900 rpm and a duty cycle Df_2 of 80% are defined. associated with a high speed threshold V_2 of 5500 revolutions / min (see curve C4). A slope P_1 is also defined between these two thresholds V_1 and V_2. For this same alternator 10 set at 120A, a duty cycle Df_3 of 70% associated with the low speed threshold V_1 and a duty cycle Df_4 of 63% associated with the high speed threshold V_2 (see curve C5) are defined. A slope P_2 is also defined between these two thresholds S1, S2. It will also be possible to define cyclic ratios which increase as a function of the speed of the alternator, as illustrated by the thresholds V_1, V_3 and the corresponding slope P_3 of the curve C6.

Furthermore, it is possible to vary the maximum duty cycle applied as a function of the temperature of the alternator 10 which can be measured or calculated. This temperature may be represented by the temperature of the chip of the regulator module 47 and / or the ambient temperature. It will thus be possible to increase or decrease the maximum power of the alternator 10 as a function of the temperature and the operating zone of its components.

As illustrated by FIG. 5, with respect to a reference duty cycle Df_ref, for example of the order of 70% at a given temperature Temp_1, Temp_2, the maximum duty cycle can increase as the temperature decreases over the range K1 and increase with temperature on the range K2 (see curve C7). According to another control law, the maximum duty cycle can gradually decrease as the temperature decreases over the range K1 and gradually increase over the range K2 (see curve C8).

FIG. 6 illustrates the various inputs and outputs of the limitation function 60 embedded in the memory 61 of the regulator module 47. The actual duty cycle Df_r is an internal data of the regulator module 47.

Speed threshold data V_1, V_2,... V_n, temperatures Temp_1, Temp_2, ... Temp_n, slopes P_1, P_2, P_n and duty cycle Df_1, DF_2, DF_n are programmed data in the memory 61 of the regulator module 47.

A map stored in this memory 61 can establish a corresponding between these speeds V_1_V_n, these temperatures Temp_1 - Temp_n, these slopes P_1 -P_n and cyclic ratios Df_1 -Df_n associated.

Each threshold V_1 -V_n, Df_1 -Df_n, Temp_1 -Temp_n, P_1 -P_n, is adjustable according to the electrotechnical definition of the machine and the needs of the motor vehicle. In other words, the memory 61 of the module Regulator 47 can be programmed according to the electrotechnical needs of alternator 10, in particular a desired current flow rate.

In order to inform the vehicle on the actual available power of the machine 10 when the limitation is applied by the function 60, a "relative duty cycle" (DF_Rel) may be sent to the engine control unit.

This ratio DF_Rel is equal to the ratio between the actual duty cycle supplied by the regulator DF_r divided by the maximum duty cycle DF_max admissible by the alternator 10, the whole being multiplied by 100, ie DF_rel = (DF_r / DF_max) x100.

It will also be possible to provide the transmission S_act signal relating to the activation state of the limitation function 60 by the regulator to the engine computer of the motor vehicle. Depending on the needs of the vehicle and the possibilities of use of the alternator 10, it will be possible to temporarily inhibit the limitation function 60 of the performance of the alternator 10. For this purpose, the engine computer may control the activation and disabling the limitation function 60.

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

1. Regulator module (47) intended in particular for regulating an excitation current injected into an excitation coil (B) of a rotor (12) of a rotating electrical machine, particularly for a motor vehicle, characterized in that it comprises a function limiting (60) a maximum electric power of said rotary electric machine (10).

2. Regulator module (47) according to claim 1, characterized in that the limiting function (60) is configured to limit a duty cycle (Df_1 -Df_n) of a voltage signal applied to the excitation coil (B ) of the rotor (12) with respect to a maximum duty cycle (Df_max) permitted by said rotary electrical machine (10).

3. Regulator module (47) according to claim 2, characterized in that the limiting function (60) is configured to adapt the duty ratio (Df_1 -Df_n) of the voltage signal applied to the excitation coil (B) of the rotor (12) according to a speed (V_1 -V_n) of the rotating electrical machine.

Regulator module (47) according to claim 2 or 3, characterized in that the limiting function (60) is configured to adapt the duty cycle (Df_1-Df_n) of the voltage signal applied to the excitation coil (B ) of the rotor (12) as a function of a temperature (Temp_1 -Temp_n) of the rotating electrical machine (10).

5. Regulator module (47) according to any one of claims 1 to 4, characterized in that the limiting function (60) is adapted to return a relative duty cycle to a motor computer.

6. Regulator module (47) according to claim 5, characterized in that the relative duty cycle corresponds to a ratio between a real duty cycle supplied by the regulator (DF_r) divided by a maximum duty cycle (DF_max) allowed by the electric machine. rotating (10).

7. Regulator module (47) according to any one of claims 1 to 6, characterized in that the limiting function (60) is adapted to return a signal (S_act) relative to its activation state to a calculator engine.

8. Regulator module (47) according to claim 2, characterized in that it comprises a memory (61) storing a map establishing in particular a correspondence between speeds (V_1 -V_n) of the rotating electrical machine and cyclic ratios (Df_1 -Df_n), said memory (61) being programmable according to the electrotechnical requirements of said rotating electrical machine (10), in particular a desired current flow rate.

9. Rotating electrical machine (10) characterized in that it comprises a regulator module (47) as defined in any one of the preceding claims.

10. Rotating electric machine (10) according to claim 9, characterized in that certain components (22, 37, 38) are undersized with respect to a power of active parts (12, 16) of said rotating electrical machine (10). ).

1 1. Rotary electric machine (10) according to claim 10, characterized in that the undersized components are at least one of:

electronic components such as diodes or transistors of a rectifier bridge (22),

- bearings (37, 38) for rotatably mounting a shaft (13) of said rotary electric machine (10),

an electrical isolation device for said rotating electrical machine (10),

a cooling device of said rotary electric machine (10),

- an impregnating varnish,

a magnetic element such as a magnet of a rotor (12).