FR3065850A1 - METHOD FOR CONTROLLING THE STOPPING OF A SPIRAL COMPRESSOR FOR AN AIR CONDITIONING INSTALLATION OF A MOTOR VEHICLE, IN PARTICULAR A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a method for controlling a scroll compressor (1) (7, 8) for controlling the deceleration of an electric motor (13) of said scroll compressor (1) (7, 8). electric motor (13) being arranged to animate a mobile spiral (8) of said scroll compressor (1) (7, 8) with an orbital motion relative to a fixed scroll (7). The deceleration of the electric motor (13) is slaved according to two distinct control laws (L1, L2) making it possible to decrease the rotational speed of said electric motor (13) linearly and according to different decelerations. The invention also relates to a compressor (1) with spirals (7, 8) whose shutdown is controlled by such a control method, and an air conditioning installation comprising such a scroll compressor.

Description

Technical area

The field of the present invention is that of scroll compressors for an air conditioning installation fitted to motor vehicles. The invention relates more specifically to a method for controlling in the stopping phase of an electric motor fitted to such a scroll compressor.

State of the art

The air conditioning installations equipping motor vehicles commonly include a scroll compressor for compressing a refrigerant circulating through a circuit of the air conditioning installation. The refrigerant is compressed between a fixed spiral and a mobile spiral housed in a compression chamber provided in a housing of the scroll compressor.

The fixed spiral is secured to the housing and the movable spiral is driven by an eccentric secured to a shaft, itself driven in rotation by a motor, in particular an electric motor. When the shaft is rotated, the movable spiral is driven in oscillation by the shaft and the refrigerant is compressed inside the chamber between the fixed spiral and the movable spiral animated by an orbital movement .

0 The shaft is therefore subjected to an unbalance following its rotation and its connection with the movable spiral via the eccentric. Such unbalance is commonly compensated for by a balancing mass fixed on the shaft. The balancing mass extends partially around the shaft, in a limited angular sector so as to form a portion of the crown. Such a crown portion axially overlaps the shaft, a radial clearance being

5 then provided between the shaft and the crown portion.

-2In this context, the implementation of the scroll compressor is regulated according to predetermined operating modes, alternating commands for activating and stopping the electric motor. When the rotation of the shaft stops following an order to stop the electric motor, the balancing mass continues by inertia its rotation around the shaft until it comes to a stop coming into contact with the shaft .

A problem posed resides in the shocks which then occur between the shaft and the balancing mass. Such shocks are sources of noise pollution which can affect the comfort of the passengers of the motor vehicle, all the more if the motor vehicle is at least partially electric, reputed to be silent.

To overcome this drawback, the radial interposition space between the shaft and the balancing mass can be arranged. Document EP 2 789 856 A2 (TOYOTA JIDOSHOKKI KK) is known in particular, which describes the interposition of an elastomer ring between the shaft and the balancing mass in order to attenuate the noise nuisances which result from their contact with one another when the tree is stopped in rotation.

However, the use of an elastomer to absorb the shocks between the shaft and the balancing mass is not satisfactory due to the fatigue to which the ring is subjected following the temperature variations which it undergoes. The hardness of the elastomer is also affected by the heat given off by the compression carried out between the mobile spiral and the fixed spiral. It appears that the durability of the elastomer ring is not reliable to respect

0 long terms the number of cycles of the compressor on and off.

Another problem is the difference in pressure of the refrigerant entering and leaving the compression chamber. Following an order to stop the electric motor, the coolant then tends to be forced back to the compression chamber, again causing shocks between the shaft and the balancing mass, which

5 are sources of noise pollution to avoid.

Document JP 2005 105990 (FUJITSU GENERAL Ltd) is also known, which describes the use of a non-return valve interposed between the outlet of the scroll compressor and the compression chamber in order to prevent such a discharge of the refrigerant.

However, the operation of such a valve is placed under the dependence of an elastic member which is also subject to fatigue and the efficiency and / or reliability of which are affected by the heat released by the compression produced between the movable spiral and fixed spiral. The valve is also not reliable enough to comply with the number of cycles of the scroll compressor on and off in the long term.

In general, the arrangements of the scroll compressor proposed to avoid impacts between the shaft and the balancing mass are unsatisfactory. In addition, such arrangements complicate the structure of the scroll compressor, which increases its costs of obtaining and / or maintenance.

The object of the present invention is to respond at least in large part to the above problems and also to lead to other advantages by proposing a new method for controlling a scroll compressor making it possible to reduce the noise nuisance generated by impacts between the shaft and the balancing mass when said scroll compressor is in the stop phase.

Another object of the invention is to improve the methods for stopping the operation of the scroll compressor and to improve the reliability of such a scroll compressor.

Another object of the invention is to simplify the structural organization of the scroll compressor, in particular to limit its costs of obtaining and / or maintenance.

Statement of the invention

0 According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a method of controlling an electric motor fitted to a scroll compressor for an air conditioning installation of a motor vehicle. The control method according to the first aspect of the invention implements a control unit fitted to the scroll compressor to regulate its operation. The unit of

5 command generates at least one control law regulating the stopping of the electric motor following reception by the control unit of an order to stop the electric motor.

In accordance with the first aspect of the invention, at least one control law generates an electric control signal controlling a deceleration of the electric motor between a first speed of rotation and a second speed of rotation less than the first speed of rotation .

In other words, the at least one control law generated by the control method in accordance with the first aspect of the invention makes it possible to produce a control of the deceleration of the electric motor between the first speed of rotation and the second speed of rotation.

The electric motor is in particular an electric motor for driving in rotation an eccentric shaft coupled to a movable spiral of the scroll compressor, to animate the movable spiral with an orbital movement relative to a fixed spiral with which it cooperates so to compress a coolant admitted inside the scroll compressor.

The stop order is notably generated by a control member that the air conditioning installation includes to regulate its operation. The control member is in particular generator of stop orders and / or activation orders of the electric motor equipping the scroll compressor, in accordance with implementation instructions which can in particular be sent by the packaging installation d air and / or by a user of said air conditioning installation.

Thanks to the control method according to the first aspect of the invention, the speed of rotation of the electric motor is regulated by the control unit following the reception by the control unit of one or more control orders issued by the control unit in accordance with the conditions required for the operation of the air conditioning installation. The instructions are for example issued as a function of a desired temperature inside a passenger compartment of the motor vehicle and / or for cooling a member of said motor vehicle heat generator in operation, such as for example a battery supplying at least in part the propulsive energy of the motor vehicle.

In this context, when the control member generates an order to stop the electric motor, a phase of stopping the electric motor is then triggered and controlled by

The control unit in particular to prohibit inertial rotation of the drive shaft of the movable spiral, as long as the electric motor does not rotate at the second speed of rotation. The control of the motor rotation is in particular operated by the control unit at least to avoid impacts between the shaft and the balancing weight.

During the stopping phase of the electric motor, the control unit generates at least one control law configured to control a deceleration of the electric motor and / or its direction of rotation. A deceleration and / or the direction of rotation of the drive shaft of the movable spiral are then controlled by the control unit which generates one or more control laws to control the rotation of the electric motor.

In other words, following the reception by the control unit of the stop order, the control unit generates at least one control law to maintain a positive drive of the shaft by the electric motor during its stop phase. A deceleration of the electric motor is then regulated by the control law which causes it to rotate from the first speed of rotation to the second speed of rotation for a predefined deceleration time: a speed of rotation of the movable spiral thus decreases so controlled and regulated by the electric motor subjected to the control method according to the first aspect of the invention, the movable spiral not decelerating by a simple inertial effect.

The ordering method in accordance with the first aspect of the invention may advantageously include at least one of the improvements below, the technical characteristics forming these improvements can be taken alone or in combination:

- The first speed of rotation is in particular the current speed of the electric motor when the stop order is received or transmitted. In addition, the second rotation speed is in particular a minimum rotation speed of the electric motor considered to be a shutdown of the scroll compressor. The minimum rotational speed is predefined according to the structure of the scroll compressor so that an inertial rotation of a balancing mass equipping the drive shaft of the movable spiral does not induce shocks between the shaft and the balancing weight at such a minimum speed of rotation, likely to cause discomfort for the passengers of the

-6motor vehicle. In other words, the first rotation speed taken into account is in particular the current speed of the electric motor regulated by the control unit when the stop command is received. The second rotation speed taken into account is in particular a minimum speed for stopping the electric motor which may be non-zero. The minimum speed is in particular predefined according to the configuration of the scroll compressor, so as to obviate the noise nuisance generated by possible shocks produced between the shaft and a balancing mass with which it is equipped when the electric motor is stopped and the balancing mass possibly continues its rotation by inertia. In other words, the notion of minimum speed is assessed according to the tolerated shocks that can be produced between the shaft and the balancing mass when the electric motor is considered stopped by turning at most at the minimum speed of rotation. The tolerance of such shocks is identified in particular with regard to the noise nuisance generated by possible shocks between the shaft and the balancing mass, which can be neglected with regard to their perception by a passenger installed in the passenger compartment of the motor vehicle. ;

- As an indication, the second speed of rotation is preferably chosen to be less than or equal to 600 rpm (600 revolutions per minute). Such a choice makes it possible to reduce as much as possible the duration of the stop phase of the electric motor during which the control unit controls a deceleration of the electric motor following reception of the stop order by the control unit, while avoiding possible noise pollution likely to be perceived by passengers;

- According to a particular embodiment, the second speed of rotation can be chosen to be substantially greater than or equal to a speed of rotation of zero value. Such an arrangement is particularly useful in the preferred case where a control law generated by the control unit causes a reversal of the direction of rotation of the electric motor at the end of the stop phase as referred to below;

- At least one control law decreases the speed of rotation of the electric motor in proportion to the first speed of rotation. The first speed is considered as a reference speed. Thus, several successive deceleration phases during successive given periods can be implemented to gradually regulate the deceleration of the electric motor. In this case, the different periods of

-7 deceleration can likewise be determined as a function of a reference duration which corresponds to the duration of the engine stop phase considered between its rotation by the control unit at the first speed of rotation and the second speed of rotation;

- According to one embodiment, at least one control law generates a decreasing variation in the amplitude of the electric control signal to control the deceleration of the motor;

- According to another complementary or alternative embodiment, at least one control law generates an electrical control signal of the type with pulse width modulation. The duty cycle of the electrical control signal varies in proportion to the variation in the speed of rotation of the electric motor. In other words, at least one control law decreases over a given period the speed of rotation of the electric motor in proportion to the first speed of rotation, the duty cycle of the electric control signal varying according to the same proportion. Over the given period, the electrical control signal generated by the control law follows a variation proportional to the variation of the speed of rotation of the electric motor, itself defined in proportion to the first speed of rotation.

more specifically, at least one control law is of the type comprising at least one polynomial law as a function of time. The polynomial law of at least one control law is likely to be for example a linear function or a decreasing exponential function;

- According to a preferred embodiment, the electrical control signal follows at least a first control law over a first period and a second control law over a second period successive to the first period. The second control law is preferably different from the first control law. In other words, the deceleration of the electric motor is regulated according to at least two laws of successive commands different from each other. The different control laws are successively applied by the control unit during periods which are specific to them and which are preferably different from one another. The first period is notably shorter than the second period. A deceleration of

-8Electric motor can be quickly controlled during the first period and be ordered during the second period more slowly than during the first period. A rapid deceleration of the electric motor is thus obtained during the first period, with a variation in the speed of rotation of the electric motor which decreases more slowly during the second period, to avoid a sudden stop of the rotation of the electric motor. at the end of its stop phase;

- alternatively, the first control law and the second control law can be advantageously grouped into a decreasing exponential function;

- Preferably, the first control law controls a deceleration of the electric motor of at least 85% of the first speed of rotation at the end of the first period;

- The first control law controls a deceleration of the electric motor to an intermediate rotation speed less than or equal to 1000 rpm at the end of the first period;

- the second control law controls a deceleration of the electric motor of at least 98% of the first speed of rotation at the end of the second period. Thus at the end of the second period, the speed of rotation of the motor is the second speed of rotation corresponding in particular to the minimum speed of rotation of the electric motor;

- a guiding coefficient of the second control law is, in absolute value, less than a guiding coefficient of the first control law. Such guiding coefficients are understood as determining the variation of the engine speed over a given period. As an indication, the guiding coefficient of the first control law is, in absolute value, equal to 8400 rpm / s (8400 rpm per second) for example. The directing coefficient of the second control law is, in absolute value, equal to 750 rpm for example;

- the first period is preferably less than or equal to one second;

- for information, the first period is chosen to be between 25% and 35% of the reference period. The second period is chosen at most equal to 75% of the

-9 reference duration. As a reminder, the reference duration extends over the entire stop phase of the electric motor controlled by the control unit;

- At the end of a phase of deceleration of the electric motor under control by the control unit, the electric control signal follows at least a third control law generated by the control unit. The third control law causes an inversion of the direction of rotation of the electric motor at the end of the second period. In other words, the control unit initially slaves a phase of deceleration of the electric motor rotating in a first direction of rotation identical to the direction of rotation of the electric motor when the stop order is received by the control unit. Upon completion of this deceleration phase, the electric motor is rotated in a second direction of rotation opposite to the first direction of rotation. The reversal of the direction of rotation of the electric motor makes it possible to prohibit a discharge of the refrigerant fluid from the outlet of the scroll compressor to a compression chamber of the coolant housing the spirals. More particularly, the reversal of the direction of rotation of the electric motor causes a counter-thrust of the refrigerant fluid out of the compression chamber towards the outlet of the scroll compressor. Thus, shocks between the shaft and the balancing mass are still avoided following the stopping of the rotation of the electric motor at the end of the deceleration phase. In other words, at the end of the execution of said at least one control law controlling a deceleration of the electric motor between the first speed of rotation and the second speed of rotation, the control unit generates a control law reversing the direction of rotation of the electric motor. The modalities of the rotation of the electric motor controlled by the third control law are defined in particular according to the proper structure of the scroll compressor, in order to obtain the adequate back-pressure of the refrigerant fluid out of the compression chamber towards the outlet of the scroll compressor . Such methods relate in particular to the speed of rotation of the electric motor and its rotation over a predefined angular range.

- The third control law generates a control signal causing the motor to rotate in the second direction of rotation according to a set angular range, preferably not exceeding one revolution.

In other words, the third control law causes the electric motor to rotate less than one revolution;

- an electric motor deceleration phase is caused in accordance with the execution of at least one control law over a deceleration time at least equal to 90% of the reference time. The rotation of the electric motor in accordance with the third control law extends over a third period at most equal to 10% of the reference duration;

- The third control law controls a rotation of the electric motor until a rotation speed slightly greater than or equal to a zero value. As an indication, at the end of the control of the rotation of the electric motor by the third control law, the speed of rotation of the electric motor is likely to be between 100 rpm and 200 rpm.

According to an improved form of the control method according to the first aspect of the invention, and following the reception of the stop order by the control unit, a control of the speed of rotation of the electric motor is controlled by l 'control unit. The control unit then generates at least one control law causing the electric motor to rotate in accordance with at least the following operations:

- during a first operation, the control unit controls a deceleration of the electric motor for a given deceleration time from the first speed of rotation to the second speed of rotation,

- Then at the end of the first operation, the control unit causes the electric motor to rotate in reverse over a range of rotation preferably less than one revolution.

More particularly, the first operation preferably comprises two successive stages of deceleration of the electric motor.

During a first step, the control unit controls a first deceleration of the electric motor during the first period from the first speed of rotation to an intermediate speed of rotation. The first speed of rotation corresponds in particular to the current speed of rotation of the electric motor. The intermediate rotation speed is notably less than or equal to 1000 rpm.

-11 Then during a second step, the control unit controls during the second period a second deceleration of the electric motor from the intermediate rotation speed to the second rotation speed. The second speed of rotation corresponds in particular to a minimum speed of rotation less than or equal to 600 rpm, which can for example be between 100 rpm and 200 rpm.

According to a second aspect of the invention, there is provided a scroll compressor comprising an electric motor for driving a movable scroll cooperating with a fixed scroll. The scroll compressor is equipped with a control unit controlling a speed of rotation of the electric motor. According to the invention, a phase of stopping the electric motor is controlled by the control unit in accordance with the implementation of a control method in accordance with the first aspect of the invention or according to any of its improvements. .

Advantageously, the scroll compressor according to the second aspect of the invention can advantageously comprise at least one of the improvements below, the technical characteristics forming these improvements can be taken alone or in combination:

- The electric motor is in particular a three-phase electric motor. The control unit is a member for regulating the intensity of the power supply current to the electric motor, preferably by modulating the pulse width of the control signal which regulates the supply of electric power to the electric motor;

- The control unit is in particular a member for regulating a variation in intensity of the electric supply current of the electric motor. This allows reliable and rapid control of the speed variation of the electric motor gradually towards the minimum speed. The deceleration of the electric motor is then controlled by the control unit by varying the duty cycle of the control signal in proportion to the change in the speed of rotation of the electric motor, in accordance with the application of at least one of the law of command generated by the control unit;

- the electric motor is a three-phase electric motor whose speed of rotation is controlled by the control unit according to a Width Modulation

-12d Pulse of the control signal regulating the supply of electrical energy to the electric motor (MLI or PWM according to the English acronym of the expression Puise Width Modulation);

- The electric motor is in particular a member for driving an eccentric shaft for driving the movable spiral, the eccentric then being engaged on the movable spiral. The shaft is equipped with a balancing mass arranged in a portion of the crown axially overlapping the shaft;

- The spirals are housed in a compression chamber provided with an inlet mouth for the admission of the coolant at low pressures inside the compression chamber. The compression chamber is also provided with an outlet for the evacuation of the high pressure refrigerant towards the outside of the compression chamber.

According to a third aspect of the invention, an air conditioning installation is proposed for a motor vehicle comprising a scroll compressor according to the invention.

Advantageously, the air conditioning installation in accordance with the third aspect of the invention may advantageously comprise at least one of the improvements below, the technical characteristics forming these improvements can be taken alone or in combination:

- The air conditioning installation comprises in particular a refrigerant circuit comprising at least the scroll compressor, a condenser, an expansion device and a heat exchanger through which the refrigerant flows;

- The air conditioning installation comprises at least one command generator command command controlling at least the implementation of the scroll compressor via the control unit with which it is equipped. The orders generated by the control member notably include an order to stop the electric motor initiating a stop phase of the scroll compressor.

Various embodiments of the invention are provided, integrating according to all of their possible combinations the different optional characteristics set out here.

-13 Description of the figures

Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several exemplary embodiments given by way of non-limiting indication with reference to the appended schematic drawings on the other hand, in which :

- FIGURE 1 is a schematic illustration of a scroll compressor according to the second aspect of the invention, configured to equip an air conditioning installation for a motor vehicle;

- FIGURE 2 is a diagram illustrating the context of the invention, in accordance with the implementation of a control method in accordance with the first aspect of the invention and making it possible to control in rotation the rotation of a motor fitted to the scroll compressor shown in FIGURE 1;

- FIGURE 3 is a diagram illustrating different stages of implementation of a control method according to the first aspect of the invention.

Of course, the characteristics, the variants and the various embodiments of the invention can be associated with one another, according to various combinations, insofar as they are not incompatible or mutually exclusive of each other. We can in particular imagine variants of the invention comprising only a selection of characteristics described below in isolation from the other characteristics

0 described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art.

In particular, all the variants and all the embodiments described can be combined with one another if nothing is technically opposed to this combination.

In the figures, the elements common to several figures keep the same reference.

Detailed description of the invention

In FIGURE 1, a scroll compressor 1 with scrolls 7,8 is arranged to equip an air conditioning installation equipping a vehicle, in particular an automobile. The scroll compressor 1 comprises a housing 2 provided with an inlet mouth 3 for

-14Γadmission of a low pressure refrigerant F1 inside the housing 2. The housing 2 is also provided with an evacuation mouth 4 for the evacuation of the high pressure refrigerant F1 from the housing 2.

The refrigerant fluid F1 is conveyed from the inlet mouth 3 to the outlet mouth 4 by a hydraulic circuit 5 arranged inside the housing 2. The hydraulic circuit 5 comprises a compression chamber 6 for compressing the refrigerant fluid Fl prior to its evacuation from the housing 2 through the evacuation mouth 4.

The compression chamber 6 comprises an inlet mouth 9 for the admission of coolant F1 at low pressures inside the compression chamber 6, and an outlet mouth 10 for the evacuation of coolant F1 at low pressure out of the compression chamber 6, then towards the outside of the scroll compressor 1. To compress the refrigerant fluid F1, the compression chamber 6 houses a pair of spirals 7.8 cooperating with each other to compress the coolant F1 to the interior of the compression chamber 6.

A fixed spiral 7 cooperates with a movable spiral 8 to compress the refrigerant fluid Fl between them. The fixed spiral 7 is integral with the housing 2 and the mobile spiral 8 is driven by an orbital movement by being driven by an eccentric shaft 11. The shaft 11 is itself driven in rotation about an axis of rotation AR by an electric motor 13 housed inside the housing 2. In the example illustrated, the shaft 11 and the electric motor 13 are preferably coaxial and are driven in rotation about a common axis of rotation AR.

To compress the coolant Fl between the spirals 7,8, the electric motor 13 is activated for its rotation in a first direction of rotation SI, which causes the shaft 11 to rotate and consequently the drive of the movable spiral 8 via the eccentric 12.

When the scroll compressor 1 is in operation, the refrigerant fluid Fl circulates at low pressure through an inlet channel 14 of the hydraulic circuit 5 from the inlet mouth 3 towards the interior of the compression chamber 6 via the mouth inlet 9. The refrigerant F1 is then compressed between the spirals 7,8 inside the chamber

-15compression 6. The refrigerant F1 is evacuated at high pressure out of the compression chamber 6 via the outlet mouth 10, then circulates in an outlet channel 15 of the hydraulic circuit 5 towards the evacuation mouth 4 for its evacuation out of the scroll compressor 1.

The implementation of the electric motor 13 is regulated by a control unit 16 on board the inside of the housing 2, which generates a control signal Sc of a rotation of the electric motor 13. The unit command controls an activation phase of the electric motor 13 by regulating its rotation, or conversely a stop phase of the electric motor 13 by regulating the interruption of its rotation.

The implementation of the control unit 16 is placed under the control of a control member 17 that includes the air conditioning installation. The control member 17 generates stop orders Oa of the operation of the scroll compressor 1 to interrupt a circulation of the refrigerant fluid F1 through a refrigerant circuit 18 that includes the air conditioning installation. Conversely, the control member 17 generates activation orders Ot for the operation of the scroll compressor 1 to cause a circulation of the refrigerant fluid F1 through the refrigerant circuit 18.

According to the direction of circulation of the refrigerant fluid F1 inside the refrigerant circuit 18, the refrigerant circuit 18 comprises at least the scroll compressor 1, a condenser 19, an expansion device 20 and a heat exchanger 21. The control unit 17 generates the stop orders Oa and / or the activation orders Ot according to requests for implementing the air conditioning installation to improve the comfort of the passenger compartment and / or for cool an organ of the motor vehicle for example.

The drive of the movable spiral 8 in an orbital movement generates an imbalance which it is necessary to compensate. To this end, the shaft 11 is commonly equipped with a balancing mass 22, in particular shaped as a crown portion, surrounding the shaft 11 by being interposed between the eccentric 12 and the movable spiral 8.

However, when the shaft 11 is stopped in rotation, the balancing mass 22 usually tends to inertially continue its course of rotation before coming to stop on

-16 the shaft 11. The shaft 11 is then struck by the balancing mass 22, which generates noise pollution. In addition, when the shaft 11 is stopped in rotation, the coolant F1 present inside the outlet channel 15 tends to be discharged towards the compression chamber 6 through the outlet mouth 10. Such a discharge of the coolant F1 has the effect of further causing shocks between the shaft 11 and the balancing mass 22 which are also sources of noise pollution. To avoid such drawbacks, the invention proposes to control by the control unit 16 the speed of rotation Vr and / or the direction of rotation SI, S2 of the electric motor 13 during its stop phase, such as illustrated in FIGURE 2 and 3.

In FIGURE 2, the control unit 16 is a calculation unit applying at least one control law F1, F2, F3 following receipt of a stop command Oa issued by the control member 17. Fa or the control laws F1, F2, F3 are each generating control signals Sc configured to control the speed of rotation Vr and / or the direction of rotation SI, S2 of the electric motor 13 in the stop phase.

At least one control law F1, F2 generates a deceleration of the electric motor 13, the stopping of which is required by the stop order Oa transmitted by the control member 17 to the control unit 16. Fa deceleration of the electric motor 13 in stop phase is controlled by the control law or laws Fl, F2, until reaching a speed of rotation Vr making it possible to reduce or even avoid an impact between the balancing mass 22 and the shaft 11 following the stopping of the electric motor 13.

The slaving of the rotation of the electric motor 13 by the control unit 16 also makes it possible to reverse its direction of rotation S1, S2 at the end of deceleration. More particularly in the deceleration phase, the electric motor 13 rotates in the first direction of rotation SI. At the end of deceleration, the control unit 16 generates a third control law F3 causing an inversion of the direction of rotation SI of the electric motor 13, which then turns in a second direction of rotation S2 opposite to the first direction SI of rotation.

With reference to FIGURE 3, the transmission at a time T0 of the stop order Oa to the control unit 16 initiates a stop phase Ph of the electric motor 13 for a reference duration Dr, preferably predefined. Fa reference duration Dr extends over a deceleration period De followed by a third period P3 ending the engine stop phase Ph

-17electric 13. The deceleration time De includes two successive periods, including a first deceleration period PI and a second deceleration period P2.

At time TO, the electric motor 13 rotates at a first speed of rotation Vc in the first direction of rotation SI. The first speed of rotation Vc is the current speed of rotation of the electric motor 13 and the first direction of rotation S1 is the current direction of rotation of the electric motor 13. During the deceleration time De, the control unit 16 puts successively implement two control laws L1, L2 which each generate a control signal Sel, Sc2. A first control signal Sel generated by the first control law L1 is different from a second control signal Sc2 generated by the second control law L2. The first control signal Sel causes a first step E1 deceleration of the electric motor 13 and the second control signal Sc2 causes a second step E2 of deceleration of the electric motor 13.

The two control laws L1, L2 cause a deceleration of the electric motor 13 over the deceleration time De from the first speed of rotation Vc to a second speed of rotation Vml. The second speed of rotation Vml is in particular a minimum speed of rotation of the electric motor 13 which can be considered as a stopping of the electric motor 13, for information less than or equal to 600 rpm.

More particularly during the first deceleration step E1, a first

0 deceleration Dl of the electric motor 13 is caused during the first period PI, which ends at an instant Tl. The first control law Ll generates the first control signal Sel during the first period PI, which is indicative of the '' order of a second and which represents approximately between 25% and 35% of the reference duration Dr.

The first deceleration Dl of the electric motor 13 is quickly operated under control

5 of the control unit 16 by application of the first control law L1, from the first speed of rotation Vc to an intermediate speed of rotation Vi. The intermediate rotation speed Vi is defined in proportion to the first rotation speed

Vc, being for information of the order of between 15% and 25% of the first speed of rotation Vc.

During the second deceleration step E2, the control unit 16 applies at the time T1 the second control law L2. The second control signal Sc2 is then generated by the control unit 16, to cause the second deceleration D2 of the electric motor 13 during the second period P2. The second period P2 extends from the instant T1 to an instant T2 ending the deceleration time De.

The second control law L2 generates the second control signal Sc2 during the second period P2 to control the rotation of the electric motor 13 from the intermediate rotation speed Vi to the second rotation speed Vml. The second period P2 is for information of the order of between 55% and 65% of the reference duration Dr. The second deceleration D2 of the electric motor 13 is operated by application of the second control law L2 significantly slower than the first deceleration Dl.

During a third step E3 initiated at time T2, the control unit 16 applies a third control law L3 generating a third control signal Sc3 during the third period P3. The third control law L3 is a control law essentially aimed at reversing the first direction of rotation SI of the electric motor 13 for its rotation in the direction of rotation S2.

The third control signal Sc3 causes the electric motor 13 to rotate in the second direction of rotation S2 during the third period P3, over an angular range less than one revolution. The third period P3 is indicative of the order of 10% of the reference duration Dr, by being initiated at the instant T2 and ending at an instant T3 closing the stop phase Ph of the electric motor 13 controlled by the control unit 16.

At time T3, the speed of rotation of the electric motor 13 is likely to be a third speed of rotation Vm2 slightly greater than or equal to a zero value. By way of indication at the end of the third period T3 of servo-control by the control unit 16 of the rotation of the electric motor 13, the third speed of rotation Vm2 can be between 100 rpm and 200 rpm min.

At such a speed of rotation Vm2, possible shocks between the shaft 11 and the balancing mass 22 can be caused during an inertial continuation of a rotation of the

Balancing mass 22. However, the noise pollution generated by such shocks can be neglected with regard to their perception by a passenger of the motor vehicle, including in the case where the motor vehicle is an electric motor vehicle or a motor vehicle. hybrid fitted with an electric motor known to be silent.

In summary, the invention relates in particular to a method of controlling a scroll compressor making it possible to control the deceleration of an electric motor of said scroll compressor, said electric motor being arranged to drive a movable spiral of said scroll compressor. an orbital movement with respect to a fixed spiral. The deceleration of the electric motor is controlled according to two separate control laws making it possible to decrease the speed of rotation of said electric motor in a linear fashion and according to different decelerations. The invention also relates to a scroll compressor, the shutdown of which is controlled by such a control method, and an air conditioning installation comprising such a scroll compressor.

Of course, the invention is not limited to the examples which have just been described and numerous modifications can be made to these examples without departing from the scope of the invention. In particular, the different characteristics, forms, variants and embodiments of the invention can be associated with each other in various combinations insofar as they are not incompatible or exclusive of each other.

0 others. In particular, all the variants and embodiments described above can be combined with one another.

Claims (14)

Claims 1. A method of controlling an electric motor (13) fitted to a scroll compressor (1) (7,8) for an air conditioning installation of a motor vehicle, the method using a control unit ( 16) equipping the compressor with 5 spirals (1) to regulate its operation, the control unit (16) generating at least one control law (L1, L2, L3) regulating the stopping of the electric motor (13) following reception by the unit control (16) of a stop command (Oa) of the electric motor (13), characterized in that at least one control law (Ll, L2) generates an electric control signal (Sc) controlling a deceleration (Dl, 10 D2) of the electric motor (13) between a first speed of rotation (Vc) and a second speed of rotation (Vml) lower than the first speed of rotation (Vc). 2. Method according to the preceding claim, according to which the second speed of rotation (Vml) is less than or equal to 600 rpm. 3. Method according to any one of the preceding claims, according to which at least 15 a control law (L1, L2) generates a decreasing variation in the amplitude of the electrical control signal (Sc). 4. Method according to any one of the preceding claims, according to which at least one control law (L1, L2) generates an electrical control signal (Sc) of the pulse width modulation type, the ratio of which cyclic varies 2 0 in proportion to the variation in the speed of rotation of the electric motor (13). 5. Method according to any one of the preceding claims, according to which at least one control law (L1, L2, L3) is of the type comprising at least one polynomial law as a function of time (Tps). 6. Method according to any one of the preceding claims, according to which the signal 2 5 electrical control (Sc) follows at least a first control law (L1) over a first period (PI) and a second control law (L2) over a second -21period (P2) successive to the first period (PI), the second control law (L2) being different from the first control law (L1). 7. Method according to the preceding claim, according to which the first control law (Ll) controls a deceleration (Dl) of the electric motor (13) to a speed of 5 intermediate rotation (Vi) less than or equal to 1000 rpm at the end of the first period (PI). 8. Method according to any one of claims 6 or 7, according to which a directing coefficient of the second control law (L2) is, in absolute value, less than a directing coefficient of the first control law (L1). 9. Method according to any one of the preceding claims, according to which at the end of a deceleration phase (Dl, D2) of the electric motor (13) under control by the control unit (16), the signal electric control (Sc) follows at least a third control law (L3) generated by the control unit, the third control law (L3) causing a reversal of the direction of rotation of the electric motor 15 (13) at the end of the second period (P2). 10. scroll compressor (1) (7,8) comprising an electric motor (13) for driving a movable spiral (8) cooperating with a fixed spiral (7), and equipped with a control unit (16 ) controlling a speed of rotation (Vr) of the electric motor (13), a stop phase (Ph) of the electric motor (13) being controlled by the control unit 2 0 (16) according to the implementation of a control method according to any one of the preceding claims. 11. scroll compressor (1) (7,8) according to the preceding claim, in which the electric motor (13) is a member for driving an eccentric shaft (11) ( 12) for driving the movable spiral (8), the shaft (11) being equipped with a mass 2 5 balancing (22) arranged in a portion of crown axially overlapping the shaft (H) · -2212. Spiral compressor (1) (7,8) according to any one of claims 10 or 11, in which the spirals (7,8) are housed in a compression chamber (6) provided with an inlet mouth (9) for the admission of refrigerant fluid (FR) at low pressures inside the compression chamber (6), and provided with a 5 outlet (10) for evacuating the refrigerant (Fl) at high pressures to the outside of the compression chamber (6). 13. Air conditioning installation for a motor vehicle comprising a scroll compressor (1) (7,8) according to any one of claims 10 to 12. 14. Air conditioning installation according to the preceding claim, in which 10 the air conditioning installation comprises a coolant circuit (18) comprising at least the scroll compressor (1), a condenser (19), an expansion device (20) and a heat exchanger ( 21) traversed by the coolant (Fl). 15. Air conditioning installation according to any one of claims 13 or 15 14, in which the air conditioning installation comprises at least one control generator (17) command generator (Oa, Ot) controlling at least the operation of the scroll compressor (1) via the unit control (16) with which it is equipped, including a stop order (Oa) of the electric motor (13) initiating a stop phase (Ph) of the scroll compressor (1). 1/1