FR2836763A1 - Control of reversible rotating electric machine for use with internal combustion engined motor vehicle, uses braking of vehicle to trigger energy recuperation mode - Google Patents

Abstract

The control method is applied to a combined-alternator starter for an internal combustion engine, and during braking of the vehicle activates energy recuperation, storing recovered energy. During vehicle braking the excitation of the machine is increased by increasing the voltage applied to the field windings. An electronic converter circuit generates the increased voltage.

Description

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 The present invention relates to a reversible rotary electric machine such as a vehicle starter alternator, especially automobile.

 Such a machine is described for example in the documents EP-A-0 260 1786, FR-A-2 745 444 and FR-A-2 745 445 to which reference may be made for more details.

 This machine operates, on the one hand, as an electric current generator and, on the other hand, as an electric motor.

 This machine of the polyphase and reversible type therefore operates alternator for including charging the vehicle battery and as a starter to drive the internal combustion engine, also called engine, the motor vehicle for startup.

 For this purpose the rectifier bridge at the output of the armature of the alternator also serves as a bridge for controlling the phases of the alternator.

 In known manner this rotating machine forming an alternator is in an embodiment associated with the motor vehicle engine flywheel being for example integrated therewith and thus rotates at the same speed of rotation as the crankshaft of the engine of the motor vehicle driving in rotating the flywheel optionally in two parts for forming a damping flywheel with elastic members intervening between the two parts or a flexible flywheel. In both cases the rotor of the machine is carried by one of these parts.

 Alternatively the reversible machine is rotated by the crankshaft through a motion transmission device such as a pulley and belt device. In this case the machine runs at a higher speed than the crankshaft.

 In all cases, the rotating electrical machine comprises: a wound rotor constituting the inductor conventionally associated with two slip rings and two brushes through which the excitation current is fed;

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 a polyphase stator carrying several coils or windings, constituting the armature, which are connected in star or delta in the most frequent case of a three-phase structure and which deliver to the rectifier bridge, in alternating operation, the converted electrical power.

 The bridge is connected to the different phases of the armature and is mounted between the ground and a power supply terminal of the battery. This bridge has for example several arms with diodes associated with MOSFET transistors or more generally with switches.

 The motor mode operation of such a machine is effected by for example imposing a direct current in the inductor and delivering synchronously on the phases of the stator phase-shifted signals of 1200, ideally sinusoidal but possibly trapezoidal or square.

 This bridge rectifier and control is controlled by an electronic module control and control. The bridge and the control module belong to a unit, called control and control unit, most often located outside the machine.

 This unit includes a computer such as a microcontroller.

 There is further provided means for monitoring the angular position of the rotor for, in the electric motor mode, injecting at the right moment the electric current in the appropriate phase and therefore in the relevant winding of the stator.

 These means advantageously of the magnetic type, alternatively of the optical type, send information to the electronic control and control unit and are described for example in the documents FR-00 14927 filed November 20, 2000 and FR-00 03131 filed on March 10, 2000.

 These means therefore comprise a target set in rotation on the rotor or the pulley of the machine and at least one sensor of the Hall effect or magnetoresistive type detecting the passage of the target advantageously of the magnetic type.

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 Preferably at least three sensors are provided, the latter being carried by the front or rear bearing that comprises the rotating electrical machine for fixedly supporting the stator and rotating the rotor.

 In EP-A-0 715 979 it is intended to operate the machine as an auxiliary motor. More specifically there is an auxiliary battery so that it can be programmed for, when the vehicle is parked, turn on the air conditioning device of the motor vehicle. To do this, the reversible electric machine and the compressor of the air-conditioning device are integral in rotation with a rotary member which is itself coupled to the heat engine by a unidirectional transmission so as to be driven by the heat engine when the latter is operating and Do not drive the engine when the machine is running on the engine when the vehicle is parked.

 In the document FR 0016133 filed 12/12/2000 it was also planned to operate the machine as an auxiliary engine especially when stopping the engine of the vehicle at a red light.

 In all cases there is provided an electronic control and control unit comprising a switch allowing, on the one hand, to connect the wound rotor of the machine to a voltage regulator device controlling the intensity flowing in the inductor when the machine operates as a generator-alternator electrical mode-and, secondly, to connect the stator of the machine to a control device, such as an inverter, sequentially controlling the phases of the armature with intervention of sensors of the angular position of the rotor when the machine operates as an electric motor, particularly in starter mode.

 The present invention aims to take advantage of this machine in a simple and economical way.

 According to the invention, a method for controlling a reversible polyphase rotating electrical machine, called alternator-

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 starter, for a motor vehicle with a combustion engine that can operate either as an alternator-powered electric generator or as an electric motor for, in particular, starting the heat engine, is characterized in that, during operation in an electric motor, said machine is driven according to two modes corresponding to different speed / torque characteristics, namely a first mode, said starter mode of the engine, for driving the engine of the vehicle to start it with high torque for low speeds, while the second mode, said mode auxiliary motor, can drive the machine alone or at least a power consumer, such as an accessory, and / or the engine with higher speeds and lower torque than those of the first mode.

 Thanks to the invention the rotating and reversible electric machine is used as an auxiliary electric motor in a speed range greater than that necessary to start the engine. Thus one can stop the engine of the motor vehicle at a red light and drive at least one accessory by the electrical machine such as the compressor of the air conditioning device. Then we can restart the engine. Alternatively the accessory is a power steering assist pump assisted so that you can turn the wheels when the engine is stopped at a red light. Of course one can in auxiliary motor mode drive several loads or alternatively drive the machine alone before switching to alternator mode.

 In one embodiment in the second mode, said machine is disconnected from the engine of the engine of the motor vehicle.

 For example, there is provided a device to no longer drive the crankshaft pulley of the engine of the vehicle or the crankshaft itself. This device may include an electromagnetic clutch, a freewheel driven, etc. A mechanical device thus makes it possible to disengage the machine

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 and the accessory to be driven, constituting a consumer of power including mechanical and / or electrical, the crankshaft.

 In a variant, the transmission ratio of the motion transmission device is varied.

 It is therefore advantageous to use different transmission ratios depending on the operating mode chosen. This can be achieved using known devices: planetary gear train, double freewheel pulley with reversed freewheeling direction. In the case of a double transmission ratio, each belt is provided with either a fixed voltage system or an automatic tensioning system, respectively on each of the soft strands. In the case of using an epicyclic gear train integrated in the crankshaft pulley or a fixed transmission ratio, the belt tension can be effected either with the aid of a fixed tensioner or a dynamic tensioner reversible, or two tensioners each acting in a single mode of operation.

 According to one characteristic, the rotor winding is overexcited in starter mode (first mode) to maximize the starting torque of the alternator-starter. Advantageously, this superaxination is also carried out in the second mode-auxiliary engine mode.

 It can thus increase the power of the machine without having to use more powerful batteries.

 The alternator-starter can thus start a more powerful motor vehicle internal combustion engine and / or start said engine under low temperatures.

 This overexcitation can be achieved by an overvoltage at the terminals of the excitation coil and / or an overcurrent in the excitation winding with respect to a conventional alternator.

 This can be achieved using an electronic booster or by acting on the number of turns of the excitation coil and on its resistance to obtain under a same supply voltage a higher number of ampere turns .

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 In one embodiment, the section of the conductive wire of the excitation coil is increased. One can play on the number of turns of the excitation coil.

 In one embodiment, the winding of the rotor is only overexcited in the starter mode and also advantageously in the auxiliary motor mode.

 In another embodiment, the rotor winding is overexcited also in alternator mode.

 Thanks to these characteristics it is proposed a command in starter mode of the supply of the excitation winding (that is to say of the winding of the rotor) which makes it possible to quickly install the starting torque, to increase it and to minimize the heat dissipation and maximize the power at startup, as well as in the second mode the machine then working as an auxiliary motor.

 The method of controlling the auxiliary motor mode can be as described below. If the accessory must be able to be used before starting the vehicle (thermal preconditioning of the programmed passenger compartment), the method consists in bringing it to its speed of rotation via the electric machine via a starter phase (rotor overexcitation, without driving the heat engine) then at a speed nO to switch to auxiliary engine mode. Once a speed nl reached, the system is loaded, the resulting speed n x then depends on the power of the load and that produced by the auxiliary motor mode; the value of this speed nx can be adjusted by more or less defluxing the rotor of the auxiliary motor.

 In the case where the vehicle to be started uses the auxiliary engine mode, there is then the possibility of an inertial start. The second engine mode is used to do this (crankshaft disengaged) and the machine is driven at max speed. achievable, then we engage the crankshaft. When the auxiliary engine mode is to be activated while an engine stop phase is provided the load (the power consumer) driven is relieved the crankshaft disengaged, and the auxiliary engine mode is activated, the speed being then

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 greater than nO, it is not passed through a starter mode, then the device is loaded again, the resulting speed nx then depends on the power of the load and that produced by the auxiliary motor mode (the value of this speed nx can be adjusted by more or less defluxing the rotor of the auxiliary motor).

 At the time of the restart, the driven load is unloaded, which results in an increase in the speed of rotation and then performs a boot identical to the inertial start by engaging the crankshaft.

 The electronic control and control unit can take into account the management of this preconditioning, as well as ensure the safety relating to people: no open hood start, open doors, restart in case of dangerous pressure drop on the system. braking, contact established after a stop phase, identification of the transponder code inhibits starting in case of attempted break-in ... as well as indicating malfunctions: belt slip, broken belt, battery charge status.

 In one embodiment, the means for monitoring the rotation of the rotor and more precisely the fixed sensors of these means are used.

 More precisely in the first mode according to the invention, the signals of the sensors connected to the electronic control and control unit (and therefore of management), are used in the direct order. In the second mode, the order of use of the signals of the sensors is changed by a permutation and a reversal of the signals of the sensors making it possible to phase out the control signal sent by the control and control unit to the phases of the stator.

 Naturally in auxiliary motor mode, the excitation current of the rotor excitation winding is set differently from that of the alternator and starter modes.

 Other features and advantages of the invention will become apparent from the description which follows, which is

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- la figure 2 montre les courbes caractéristiques (couple et puissance en fonction d'une vitesse de rotation (nombre de tours par minute)-à savoir celle du rotor de la machine- proportionnelle à celle du moteur thermique du véhicule) ; - la figure 3 illustre un circuit d'alimentation conforme à un mode de mise en oeuvre possible pour l'invention. purely illustrative and not limiting and should be read with reference to the accompanying drawings in which: - Figure 1 is an axial sectional view, without axial section of the rotor of the target and the target holder, an alternator - starter according to the FR 0003131;

FIG. 2 shows the characteristic curves (torque and power as a function of a speed of rotation (number of revolutions per minute) - namely that of the rotor of the machine - proportional to that of the thermal engine of the vehicle); - Figure 3 illustrates a power supply circuit according to an implementation mode possible for the invention.

 In the figures the reversible rotary electric machine of the polyphase type is an alternator-starter of the type indicated above is described for example in the documents FR-00 14927 and FR-00 03131 mentioned above.

 This machine here has the structure of a conventional alternator for example of the type described in EP-A-0515259 to which reference will be made for more details.

 This machine, as shown in Figure 1, is therefore internally ventilated (air cooling), its claw rotor 4 carrying at least at one of its axial ends a fan. 43,44 to 45 blades. In a variant, the machine is cooled by water.

 More precisely in FIG. 1, the rotor 4 is a claw rotor with pole wheels 41, 42 carrying axially orientated and trapezoidal teeth 143 at their outer periphery. The teeth 143 of one pole wheel are directed towards the teeth of the other pole wheel, said teeth of generally trapezoidal shape being distributed nested from one pole wheel to the other.

 Of course, as described for example in document FR-A-2 793 085, permanent magnets may be inserted between the teeth of the pole wheels to increase the magnetic field. These teeth are derived from the outer periphery of a transverse flange that includes each pole 41,42.

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 The rotor 4 carries centrally an excitation coil between the flanges of its pole wheels. This winding is visible for example in Figure 3 of the document FR 0003131 and is carried by cores from the flanges of the wheels 41,42 or a core constituting a spacer between said flanges.

 The excitation winding comprises an electrically conductive element which is wound with the formation of turns. This excitation coil, when activated, magnetizes the rotor 4 to create with the teeth 143 pairs of magnetic poles North-South. The ends of the rotor winding are each connected to a slip ring 6.7 on each of which rubs a brush (not referenced). The brushes are carried by a brush holder 16 secured to the rear bearing 14 of the machine bearing a central ball bearing (not referenced) rotatably supporting the rear end of the shaft 3 to be secured, here by knurling, the rotor 4.

 The front end of the shaft 3 is rotatably supported by a ball bearing 11 carried by the front bearing 13 of the machine. The front end of the shaft carries on the outside of the machine a motion transmission member in the form of a pulley 1 belonging to a motion transmission device comprising at least one belt engaged with the pulley. The motion transmission device establishes a connection between the pulley and a member, such as another pulley, rotated by the internal combustion engine of the vehicle. The shaft 3 is threaded at its front end for fixing the internally hollow pulley 1 by means of a nut 2 as visible in this figure 1. The axis of axial symmetry XX defines the axis of rotation of the machine rotating electric here of the three-phase type.

 When the machine-here an alternator-starteroperates in alternator mode that is to say as an electric generator, the pulley is rotated by the internal combustion engine of the vehicle via at least the aforementioned belt. When the machine is running in starter mode

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 that is to say in electric motor, the pulley rotates the vehicle engine via the belt.

 Alternatively the motion transmission device comprises at least one chain, or at least one gear, or at least one pinion so that the pulley 1 can be replaced by a gear, a gear, a pinion or other member constituting the motion transmission member.

 The front and rear bearings 13, 14, in known manner, are perforated for the internal ventilation of the machine, are interconnected, for example using tie rods as shown in Figure 1, and belong to the support S of the machine intended to be fixed on a fixed part of the vehicle.

 Alternatively, in known manner, the supports are in sealing contact with each other and are hollowed out internally at their outer periphery of axial orientation for forming a circulation channel of a cooling fluid, such as the cooling fluid of the engine of the vehicle, so that the machine is cooled; this type of cooling being conventionally called water cooling.

 The support S thanks to the bearings 13,14 internally carries fixedly at its outer periphery the stator 8 of the machine comprising a body, usually constituted by a bundle of sheets, carrying coils or more generally windings whose outputs are connected to the bridge rectifier and control aforesaid.

 The coils or windings of the stator are formed by son or windings in electrically conductive bars as described for example in the documents WO92 / 06527 and FR 00 16738 filed on 21/12/2000; the bars may be of rectangular section. The wires or bars are electrically insulated through the body of the stator 8 and are interconnected to form networks extending on either side of the body of the stator 8 forming a first and a second updo.

 More specifically, in known manner, the machine comprises several phases each comprising an input and an output and

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 the wires or bars are interconnected to form said networks and connect the input of the phase to the output of the phase by forming at least one winding per phase. The machine can therefore be of the hexaphase type as in FIGS. 6 to 9 of document FR 00 16738 or three-phase as in FIGS. 2 to 6 of this document FR 00 16738. The wires or bars pass axially through electrical insulation in a form of FIG. realization of the notches formed in each sheet of the stator body. In a variant, the wires or bars pass through the stator body centrally and electrically insulated by being fixed to the body of the stator by resin, as described for example in document US Pat. No. 5,097,167.

 The stator 8, constituting in alternator mode the armature of the machine, surrounds the rotor 4, constituting in alternator mode the inductor of the machine. The brushes, via the brush holder 16, are connected to a voltage regulator device of the alternator to maintain the voltage of the alternator at a desired voltage here of the order of 14V, for a battery of 12V.

 The rectifier bridge, the electronic control and control unit of the bridge rectifier arm are here mounted in an electronic box located outside the machine. It is the same in one embodiment of the voltage regulator device.

 Alternatively the housing is mounted on the machine for example at the rear or the outer periphery thereof.

 The voltage regulator device is in a variant mounted outside the housing being electrically connected thereto. All combinations are possible.

 This housing carries switching means here comprising power switches, an electronic control and control unit and an overexcitation circuit.

 The electronic unit comprises a computer, such as a microcontroller, receiving sensor information 52 described below.

 The alternator-starter machine here has stator windings and a rectifier bridge connected in parallel

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 with a battery B of a vehicle and an excitation winding secured to the rotor and supplied via an overexcitation circuit.

 This overexcitation circuit is active in start-up mode (alternator-starter operating as an electric motor) to make the start-up torque of the alternator-starter and start more easily the internal combustion engine, also called the engine, of the motor vehicle either during a cold start, or during a restart after for example a stop at a red light; the engine has been cut to reduce fuel consumption and thus achieve a function called Stop and GO.

 This overexcitation circuit receives as input the edge network voltage delivered by the battery and / or the alternator and delivers across the excitation winding a voltage greater than this edge network voltage.

 The assembly further comprises, in addition, switching means (power switch for example) controlled by the electronic control unit.

 This control unit is associated with the voltage regulator device of the alternator and controls for example the switch by a pulse width modulated signal.

 Also, the control and control unit may comprise means that allow, in the case where the alternator-starter would discharge on the on-board network being disconnected from the battery (load dump case according to the English terminology). -Saxon usually used by those skilled in the art), to immediately control the opening of the power switch to achieve rapid demagnetization of the alternator, including its rotor.

 The overexcitation circuit also acts when the machine is operating in alternator mode.

 The overexcitation circuit is controlled so that the voltage or the overexcitation current that it delivers is always less than a voltage or a current corresponding to

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 the maximum permissible temperature for the alternator-starter and the components associated with it, particularly when the machine is operating in alternator mode.

 In a first mode of implementation, there is provided on the machine at least one thermal sensor that allows to know precisely the temperature of the hottest element.

 A control loop makes it possible to maintain the voltage and / or the overexcitation current delivered by the excitation circuit at values that permanently impose on the machine, in particular in alternator mode, a temperature below the maximum temperature. admissible for this one and its components.

 According to a characteristic of this embodiment, when the machine operates in starter mode, in particular for starting the motor vehicle, the overexcitation (voltage and / or current delivered by the overexcitation circuit) is greater than the overexcitation in alternator mode in order to maximize the starting torque (and thus power) of the starter alternator.

 According to one characteristic, the rotor current, that is to say the current of the excitation coil, is magnetized with a current greater than that required in the alternator mode.

 Alternatively one can act on the excitation voltage and increase it over the alternator mode.

 In another embodiment, which is a preferred embodiment, the overexcitation circuit is controlled so that the voltage or current it delivers is always less than a voltage or a current which, for an The given angular velocity for the rotor, especially in alternator mode, would correspond to a predetermined maximum temperature by tests or other means.

 The overexcitation circuit is in a controlled embodiment, depending on the angular velocity of the rotor, so that the overexcitation voltage or current that the overexcitation circuit delivers is always less than

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 at the maximum voltage or current that corresponds to this angular velocity.

 The machine is thus used in alternator mode to the maximum of its possibilities.

 As a further variant, it is possible to predict that it is the cyclic ratio of the pulse width modulated signal which controls the switch which is slaved, either as a function of the temperature or as a function of the angular speed of the rotor, so that the temperature of the hottest component of the machine is always lower than the maximum permissible temperature.

 In starter mode, a higher duty cycle is used here than in alternator mode. For example, the duty cycle is 100% in starter mode and 75% in alternator mode.

 The implementation of this temperature control can be achieved by measuring the temperature of the hottest component and comparing it with a reference voltage.

 Servo-control can also be achieved by estimating the temperature of the hottest component from a temperature easy to measure (typically in the controller and deducing said temperature from the hottest component.

 This excitation circuit is for example a voltage-boosting chopper circuit which comprises an inductance mounted between a supply line at the positive voltage of the network and a switch which is also connected to ground.

 The excitation circuit is therefore an electronic boost according to a characteristic.

 Advantageously, the boost is greater in starter mode than in alternator mode.

 In the case where there is accidentally a break in the electrical connection between the alternator and the battery (unload dump "), it implements rapid demagnetization for example by means of switches.

 In an embodiment at the closing of a contact switch, the excitation winding of the

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 rotor 4 with a voltage and / or a large current, for example with a voltage of the order of 20V and a current of 10A, knowing that the nominal voltage is normally 14V.

 The voltage and / or the large current thus generated make it possible to quickly install a large starting torque.

 The supply voltage of the rotor winding is then decreased in a second phase to be passed for example to 12 V or 6 A at the end of a given time, which avoids overheating the coil winding. excitation of the alternator-starter.

 Then, the voltage becomes negative when the start is detected, so as not to overload the engine in the start phase and prevent it from stalling when switching to alternator mode.

 This voltage reversal is obtained for example by means of a fast demagnetization switch.

 For more details we refer to the document FR 00 16133 filed 12/12/2000 and in particular to Figures 5 and 6 thereof.

 The embodiments of Figures 7 to 11 of this document are also possible.

 The rapid demagnetization switch therefore makes it possible to quickly deactivate the excitation winding by stopping the current therein.

 Thanks to its provisions the torque-and therefore the starting power-of the alternator-starter is increased to the maximum. The rotor is therefore magnetized with a current flowing in the excitation winding greater than that required in alternator mode.

 Of course the overexcitation of the excitation winding can be achieved in another way. For example, it is possible to act on the number of turns of the rotor excitation coil and on its resistance in order to obtain on the same supply voltage a higher number of ampere turns. For example, considering an excitation winding of a rotor of a

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 conventional alternator comprising N turns of section A corresponding to a resistor R, an embodiment of the invention consists in providing this excitation winding N / 2 turns of section 2A which corresponds to a resistance R / 4.

 The current thus becomes 4 times greater than that of the conventional alternator for the same voltage. The number of ampere-turns is twice that of the conventional alternator.

 As a variant, the voltage can be increased by means of a booster in the aforementioned manner. For example, it is possible to apply, with the aid of an electronic booster, a voltage close to 1.5 times the nominal voltage or with a current of 1.5 times the rated current in alternator mode.

 This boosting causes an increase in the electric current flowing through the excitation coil.

 In the operation phases in alternator mode the excitation voltage is then reduced to a value allowing a satisfactory operation for the load balance.

 For example, when the overexcitation circuit comprises above a control with a PWM-KPWM signal, it can act on the excitation duty cycle to reduce it in alternator mode to have a electrical power to dissipate in the excitation coil equivalent to that of a conventional coil.

 Overexcitation can occur only in starter mode.

 Advantageously an overexcitation is also produced in alternator mode which allows to have more power for consumers and / or loads for a nominal voltage of 14V with a 12V battery without the need for a more powerful battery, knowing that vehicles More and more cars are equipped with equipment requiring more energy.

 In starter mode (operation in electric motor) the overexcited alternator-starter can cause more consumers and / or loads, especially when the engine

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 the vehicle is stopped at a red light, the starter alternator operating as an auxiliary engine.

 Thanks to the overexcitation the starting torque can be produced more quickly and can increase and decrease more easily thanks to the rapid demagnetization.

 Overexcitation can be achieved with an excitation winding of lower resistance than that of a conventional alternator.

 In any case the rapid demagnetization avoids unnecessarily drawing torque on the engine at the beginning of operation in alternator mode.

 The engine will not stall at the beginning of its start-up at idle-car at this time, the drive coil is not activated. The magnetization of the excitation coil in alternator mode is done once the engine is launched. This demagnetization is used in case of Load dump.

 Of course once the start torque installed quickly, we can achieve other forms of curves that allow for example a gradual decrease.

 No useless torque being removed thanks to the rapid demagnetization.

 After starting, switching to alternator mode can be done in a known manner with a progressive load, or a speed control to prevent stalling of the engine of the vehicle.

 Of course, alternatively, servocontrol in alternator mode can be performed with an open loop.

 It is therefore possible not to use temperature control in alternator mode.

 The alternator flow curve (intensity versus revolutions per minute) is in a programmed embodiment using pulse width modulated signal duty cycle thresholds set in advance and corresponding to the needs of the motor vehicle.

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 This programming reduces, for example, the intensity at high rotational speeds and at high flow rates, for example of the order of 90 to 120 amperes, in particular to avoid the use of too expensive rotor shaft bearing ball bearings. For economic reasons, we can penalize ourselves in the high speeds of rotation. In low speed ranges, overexcitation is achieved.

 It is the same in the average speed range, around 3000 revolutions per minute, it is an overexcitation, the current output is then of the order of 60 to 90 amperes.

 Everything can be pre-programmed in advance, depending on the tests.

 Overexcitation of the excitation winding can be achieved by varying the number of ampere turns of said winding.

 Of course we can, in alternator mode, achieve overexcitation in the high rotational speeds of the rotor through the control of the aforementioned parameter.

 Alternatively, the excitation winding can be shaped using a shaping tool to give it at its outer periphery a pointed shape or a barrel shape so that the winding comes closer to the teeth. axial of the claw rotor as described for example in document FROO 06853 filed May 29, 2000. This is favorable for overexcitation.

 Of course the alternator-starter can be located at the clutch of the motor vehicle as described for example in the document FR-A-2 782 356 filed July 28, 1999.

 Thus the rotor of the alternator-starter can be implanted between the internal combustion engine of the motor vehicle and the reaction plate of the friction clutch.

 Alternatively the rotor may be located downstream of the friction clutch.

 In both cases the rotor is rotated by the flywheel of the motor vehicle connected in rotation to the crankshaft of the engine of the motor vehicle.

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 The rotor can be carried by the flywheel, which rotates the friction clutch, the reaction plate then constituting the rear end of the flywheel.

 As aforesaid, this flywheel may be in two parts so that the rotor is in this case carried by the primary portion, integral in rotation with the crankshaft, or the integral secondary portion of the reaction plate of the clutch for cooperating with a face of the friction disc of the clutch. Elastic members, as well as possibly a torque limiter, intervene between these two parts for good vibration filtration and formation of a double damping flywheel. Alternatively these two parts are integral, one may be axially flexible for forming a flexible flywheel.

 The alternator-starter can be brushless. In a variant, the alternator-starter comprises a rotor with salient poles with excitation coils associated with each pole.

 There is further provided means for monitoring the angular position of the rotor for, in the electric motor mode, injecting at the right moment the electric current in the appropriate phase and therefore in the relevant winding of the stator.

 These means advantageously of the magnetic type, alternatively of the optical type, send information to the electronic control unit and are described for example in documents FR-00 14927 filed November 20, 2000 and FR-00 03131 filed March 10, 2000 .

 Thus, in FIG. 1, a target 50 is fixed on a fixed port rotated on the rotor 4. This target holder is implanted axially between the rotor 4 and the rear bearing 14 radially below the blades 45 of the fan 44. This portecible forms a spacer between the rotor 4 and the inner ring of the ball bearing of the rear bearing 14 and partially surrounds the outer ring of this ball bearing as shown in the figures of FR 0003131 supra. On the transverse bottom of the rear bearing is fixed a sensor holder 53 which carries here

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 three sensors 52 of the Hall effect type, alternatively magneto-resistive type whose resistance varies depending on the magnetic flux.

 The target 50 is magnetic here and alternately carries North and South poles. The reading by the threshold sensors 52 is of the radial type. To do this, the sensor holder 53, for example of plastic, has portions 55 of axial orientation 55 passing through a hole 54 of the large size of the bearing 14. Each portion 55 carries a sensor 52 implanted radially above the target 50 of axial orientation carried by the outer periphery of the target holder. Alternatively the target is castellated and the sensors are magneto-resistive type.

 The sensor holder 53 has lugs 56 with oblong holes each traversed by a fixing bolt 57 at the bottom of the bearing 14. The portions 55 are located radially below the blades 45. The sensor holder 53 thus has a circumferentially adjustable position relative to the bearing 14. A perforated protective cover 17 covers the rear part of the machine and in particular the door 16 and the sensor holder 53. This cover 17 and fixed on the rear flange 14 constituting with the front bearing 13 the fixed support S of the stator 8 of the synchronous type machine.

 As a variant, the reading is axial, since the sensors are located axially in front of the target. Alternatively, the target port is located between the bottom of the front bearing 13 and the rotor instead of the spacer 70 resting on the inner ring of the ball bearing. 11. The sensor holder 53 is then fixed in an angularly adjustable manner on the front bearing 13.

 In a variant, the target is fixed on the pulley 1 facing the sensor holder angularly adjustable by the front bearing 13 as described in document FR 00 14927 mentioned above; the reading being of the axial or radial type.

 In a variant, the sensors are mounted on a carrier piece carrying the stator of the machine at its outer periphery and making it possible to define a precise air gap with the rotor. The

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 flywheel carries the rotor of the machine as well as the reaction plate of the clutch. Bearing means, such as at least one ball bearing, occur between the flywheel and the inner periphery of the carrier piece having a U-shaped portion partially surrounding the rotor carrying a coding wheel. The sensors are located opposite this encoder wheel as described in FIGS. 23 to 25 of document FR 0016710 filed on 20/12/2000. The machine is then of the synchronous type.

 The target advantageously comprises a number of pairs of north-south magnetic poles identical to that of the rotor 4. The target carrier is non-magnetic in nature or magnetic variant. The target may comprise ferrites and / or rare earths or contain only inert sectors fluxed by the rotor magnetic field.

The means for monitoring the angular position of the rotor are therefore of the magnetic type with Hall effect or magnetoresistive sensors
In a variant, these tracking means are of the optical type and therefore use optical sensors such as optoelectronic sensors.

 In all cases the sensors send information to the electronic control and monitoring unit. Here three sensors are provided at the rate of one sensor per phase, the signals of the sensors being, in known manner, out of phase with an electrical angle of 1200 for sequential supply of the phases of the stator 8 for creating a rotating electromagnetic field.

 The present invention aims in particular to improve the operation of the auxiliary engine of this machine here of the synchronous type.

 According to the invention, a method for controlling a reversible, multiphase, rotating electrical machine, called alternator starter, for a motor vehicle with a heat engine that can operate either as an alternator-powered electric generator or as an electric motor for, in particular, starting the engine.

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 thermal device is characterized in that during operation in electric motor said machine is driven in two modes corresponding to different speed / torque characteristic curves, namely a first mode, said starter mode of the engine, for driving the engine the vehicle to start it with high torque for low speeds, while the second mode says auxiliary engine mode, can drive the machine alone or at least a power consumer, such as an accessory, and / or the engine with higher speeds and lower torque than the first mode.

 In one embodiment, the sensors are operated in two modes.

 More precisely, as can be seen in FIG. 2, thanks to the invention, the characteristic curves A, BC, D respectively for the power and the torque as a function of the number of revolutions per minute of the rotor 4 of the machine are obtained during operation in an electric motor. whose rotational speed is proportional to that of the crankshaft of the engine of the vehicle.

 The power curve A, B quickly passes through a maximum and then decreases (portion A). From a threshold n change mode to move to the second mode-operation auxiliary engine-and describe the portion B of the curve A, B.

This is achieved before the power vanishes for here
1500 rpm. This cancellation depends, of course, on the applications. The dashed curve A 'corresponds to the extension of the characteristic curve A without the provisions according to the invention and thus power cancellation for 1500 rpm.

Similarly, considering the torque curve C, D, it can be seen that it comprises two sections, namely sections C and D respectively corresponding to the first and second modes according to the invention with a change of curve at the point n, the curve
This lengthens the curve C to cancel here at 1500 rpm. The

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 point n here corresponds to a high torque close to the maximum of the curve A.

 Thanks to the invention, a torque is produced after a speed threshold here of 1500 revolutions per minute.

 Of course, in the second mode of operation as an auxiliary motor, the excitation current of the rotor excitation coil is set differently from that in the starter mode and in the alternator mode.

 It can be seen that the maximum torque is close to the zero speed because, as mentioned above, the torque increases rapidly initially.

 According to one characteristic, the setting of the sensors 52 of the means for monitoring the angular position of the rotor 4 is optimized.

 The signals sent by the sensors 52 to the electronic control and control unit are used in direct order as long as the auxiliary motor function is not activated or the activation speed corresponding to point n of FIG. 2 is not reached. This corresponds to curves A and C.

 The electronic control unit controlling the rectifier bridge, also called inverter, having arms with diodes as visible for example in EP-A-0 260 1786, FR-A-2 745 444 and FR-A-2 745 445 to which reference may be made for more details, the arms of the inverter (of the bridge) are driven directly to power sequentially the windings of the phases of the stator 8 each comprising at least one winding of electrically conductive elements.

 As soon as the activation speed is reached (point n of FIG. 2), a permutation and a reversal of the signals of the sensors are carried out simply and economically.

 This here makes it possible to phase out the control signal of the arms of the inverter (each arm being associated with a phase) of electrical power with respect to the direct control of the phases of the stator. Further permutations in electrical steps of 60 are possible in order to reach a higher speed. An offset

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 around the speed reference (point n) enables or disables this function. Everything happens as if we had a new phase sensor in the second mode.

 For example, with respect to the position 0 corresponding to a direct reading of the signals of the sensors by the control and control unit for sequentially controlling the arms of the rectifier bridge, a permutation of the signals of the signals is carried out at the threshold speed n. sensors-a phase shift of 1200-then an inversion to arrive at the position 1 consisting of a phase-shift of -60 relative to the position 0. This is generalizable.

 Thus one can obtain in the second mode another change for a speed n2 greater than n by performing a new phase shift of the electrical sensor signals.

This is achieved by a permutation of the sensor signals relative to the 0 position to arrive at the 2 position shifted by 120 relative to the 0 position and 60 relative to the 1 position.

 As can be seen from the description, a new change-position 3 can be obtained for a speed n3 greater than n2 by permuting and inverting the signals of the sensors with respect to the position 2. It is then shifted or out of phase by -180 relative to the 0 position.

 A new position 4 is obtained for a higher speed n4 by performing a permutation (-120) of the signals of the sensors with respect to the position 2 and so on for the position 5 (n5 greater than n4 and permutation and inversion with respect to the position 4) to reach a position 6 corresponding to a phase shift of-360 relative to the position 0, ie to a return to the position 0.

 All these variations lead to the formation of new sensors at each position and using the same sensors either by permutation and inversion, or by inversion of the signals of the sensors.

 The function can be obtained either by computer processing using the calculator of the electronic unit of

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 command and control and prerecorded tables either using discrete components as depicted in Figure 3.

 Of course, the rotational speed of the crankshaft of the heat engine is measured either directly or by means of a multiplication ratio, for example by measuring the speed of rotation of the rotor 4.

 Each sensor is here dedicated to one of the phases of the stator of the machine here of the three-phase type. These sensors detect in association with the target, the angular position of the rotor 4 and sends information to the electronic control and control unit so that it controls via the arms of the rectifier bridge the current injection in the winding of the phase concerned. This occurs when the sensor concerned sends from a threshold an activation signal respectively C1, C2, C3 to said unit.

 Apart from this activation, the sensors send a non-activation signal (-) C1, (-) C2, (-) C3 to said unit.

 In FIG. 3 each phase sensor 1, 2, 3 sends, when it is activated, its signal C1, C2, C3 to a first logic gate receiving information from a block adapted to indicate that the speed n is reached and that the Auxiliary motor function is activated.

 More precisely when the speed of rotation of the crankshaft corresponding to the threshold speed n is not reached, this block sends an information here. (-) n to the first logic gate associated with each phase sensor 1,2, 3.

 These first logic gates are of the type and when one of the phase sensors is activated and the speed n is not reached (information (-) n)), the first logic gate delivers a signal (reference < = 1 in Figure 3).

Thus, as long as the speed n is not reached, the phase sensors normally work according to the first mode.

 As soon as the speed n is reached and the motor function activated, the aforementioned block sends information n to second logic gates, each second gate being associated with one of the phase sensors.

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 Thus the second logic gate of the phase sensor 1 is connected to the phase sensor 3 and the block, the second logic gate of the phase sensor 2 is connected to the phase sensor 1 and to the block, and finally the second logic gate of the phase sensor. phase 3 is connected to the phase 2 sensor and the block.

 More precisely these second logic gates are connected to the outputs of these sensors indicating that the sensor is inactive.

 When the speed n is reached and the auxiliary motor function is activated, the second logic gate type and delivers a permuted and inverted signal.

 More precisely, the second logic gate of the phase sensor 1 delivers this signal when the phase sensor 3 is inactive; the first logic gate no longer delivering a signal because the speed condition lower than n is no longer fulfilled. Everything happens as if we had a new C'1 phase sensor that sends information to the electronic control and control unit.

ou. The equation of this new sensor is C '= Cl. (-) n + n. (-) C3 in which C'1 is the active signal delivered by this new sensor, corresponds to the condition and, (-) C3 or (-) (n) to the inactive condition of the sensor C3 and the block and + to the condition

or.

 Below the speed n the new phase 1 sensor corresponds to the phase 1 sensor and is therefore active (delivers a signal) only when the phase 1 sensor is active. As soon as the speed is reached and the auxiliary motor function is activated, the new phase sensor 1 is active only when the phase 3 sensor is inactive.

 It is the same for phases 2 and 3, the new phase 2 and 3 sensors having for equation C'3 = C3. (-) n + n. (-) C2 and C'2 = C2. (-) n + n. (-) Cl.

 Thus, in the second mode, the electrical phase-60 control signals are shifted relative to the direct control (relation C. (-) n) satisfied.

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 Of course as explained above it is necessary in the auxiliary engine function to disengage the machine and the accessory to drive the crankshaft. This device may comprise an electromagnetic clutch as described for example in document FR-A-2 648 886.

 In this case the engine comprises a fixed nose on which is rotatably mounted the crankshaft pulley, whose end is rotatably connected to a connecting piece integral with the plate of the electromagnetic clutch, whose coil is adapted to be secured. at nose.

 The fixed plate of the clutch is secured to one of the flanges of the pulley.

 Freewheel controlled devices can be used as described for example in the aforementioned EP-A-0 715 979.

 As a variant, different transmission ratios are used in the above manner depending on the operating mode chosen. For example one can use a transmission in the form of a variable speed drive with a driving pulley, a driven pulley and a belt looped endlessly on one and the other of these pulleys. Each pulley comprises two frustoconical flanges of which at least one is mounted axially movable under the control of elastic return means.

 Thus, when the movable flange of the driven pulley is in the extreme forward position, the movable flange of the driving pulley is in the extreme rear position and vice versa as described in the above-mentioned document FR-A-2 648 886 to which reference may be made.

 Of course, the present invention is not limited to the described embodiments.

 Thus the stopping and restart phases can be managed either by the ECU (control unit of the engine) of the vehicle or by the microcontroller of the engine of the driving electronics, one or the other of the solutions using the information from the vehicle and transmitted either in analog, in digital via a link for example

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 according to the Anglo-Saxon terminology of the CAN type, VAN ...., or by a combination of both.

 The regulation part of the edge voltage generated during the alternator modes is controlled using the microcontroller. During the braking of the vehicle, the regenerative braking mode is activated, the excitation rate is increased in order to take a higher torque from the motor, the energy thus recovered is stored in a device studied for this purpose (Ultracapacity for example) which will restore the electrical energy to the onboard network for a new start if the braking action was to stop the vehicle or for connected consumers, reducing the torque taken by the generator which increases the efficiency of the system.

 This energy can also be used during stop phases and use auxiliary motor mode. This engine used to drive is an air conditioner or any other mechanical device.

 In order to ensure the cold start of the vehicles of large displacements, it is possible to use in cold weather an associated auxiliary starter as described in the document FR-99 10316 filed August 9, 1999. The control of this starter is only activated when the thermal sensor of the system electronics detects a temperature below a minimum value. The steering strategy then becomes: tO activation of the solenoid of the auxiliary starter, and pre-excitation of the excitation winding of the rotor with the aid of the control and control unit. This order can be modified and adjusted taking into account the time constants of the two machines. Then we activate the start mode.

 The powers provided by each machine are then additional and thus allow startup. As soon as the sensor of the electronics of the system detects a temperature higher than tO when the power is turned on, the starter is no longer used.

 This strategy makes it possible to drive at speeds higher than that of a starter during normal operation.

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 thermal engine and thus to make the start cleaner in terms of engine emission.

 In order to facilitate the wiring of the system on the vehicle, advantageously use will be made of a connection device with at least one connector with two subassemblies provided with a single fastening means, such as a screw and nut means, for clamping between they electrically conductive elements homologous to two subsets as described in documents FR-01 00931 of 24/01/2001 and FR-00 10737 of August 18, 2000.

 Of course in the second mode in electric motor operation, the machine can be used to drive the engine over the speed of rotation-here 1500 rpm for which the power is canceled. Thus the starting of the engine is correct.

 It is also possible, especially after starting the engine, to drive the electric machine alone in the second mode before switching to alternator mode. For example, it is possible to disengage the load (the mechanical power consumer) using, for example, an electromagnetic clutch mounted within a pulley of which one of the flanges forms a secondary pulley as described in document FR-A -2 648 886. After stopping at the red light it is unloaded-the load dislodges that is to say that disconnects the power consumer, during the restart operation.

Claims (10)

1. A method for controlling a reversible polyphase and rotating electrical machine, said alternator-starter, for a motor vehicle with a heat engine that can operate either in generator-alternator mode electric-or in electric motor for including start the engine, said electric machine being connected to an on-board network characterized in that in alternator mode, the braking mode is activated with energy recovery during the braking phases of the motor vehicle.  2. A method of controlling a rotary electric machine according to claim 1 characterized in that during the braking phases, the excitation rate is increased in order to take the upper torque on the motor.  3. A method of controlling a rotary electrical machine according to claim 2 characterized in that the increase in the excitation rate is achieved by an overvoltage at the terminals of the excitation coil.  4. A method of controlling a rotary electrical machine according to claim 3 characterized in that the overvoltage is achieved by an electronic booster.  5. A method of controlling a rotary electric machine according to any one of the preceding claims characterized in that the recovered energy is stored in a device for storing energy.  6. A method of controlling a rotary electric machine according to claim 5 characterized in that the energy storage device is an ultracapacity.  7. A method of controlling a rotary electric machine according to claim 5 or 6 characterized in that the energy <Desc / Clms Page number 31>  stored in the energy storage device is restored to the onboard network for a new start of the alternator starter.  8. A method of controlling a rotary electric machine according to claim 5 or 6 characterized in that the energy stored in the energy storage device is restored to the on-board network for the supply of connected consumers.  9. A method of controlling a rotary electrical machine according to claim 5 or 6 characterized in that the energy stored in the energy storage device is returned to the alternator-starter operating in auxiliary motor mode.  10. A method of controlling a rotary electric machine according to claim 5 or 6 characterized in that the energy stored in the energy storage device is returned to the alternator-starter operating in stop mode.