A method for closed-loop correction of a rotational speed of a compressor for refrigerant fluid in a thermal conditioning system of a vehicle with electric powertrain

Abstract

There is described a method for the closed-loop correction of a rotational speed of a compressor (EAC) for refrigerant fluid in a thermal conditioning circuit of a vehicle with an electric powertrain. Thanks to the method according to invention, an integral rotational speed correction (nComP_int) of the compressor (EAC) immediately adapts to a modified cooling condition, thereby avoiding a problem of freezing on a cabin evaporator (EVAP) and generally a sensation of reduced comfort in the passenger compartment, with an accuracy which is guaranteed by the closed-loop control.

Description

[0001] "A method for closed-loop correction of a rotational speed of a compressor for refrigerant fluid in a thermal conditioning system of a vehicle with electric powertrain"

[0002] ★ ★ ★ ★

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the Invention

[0005] The present invention relates to vehicles with electric powertrain, especially to BEVs (Battery Electric Vehicles ) . In more detail , the invention was developed with reference to the control of a compressor for refrigerant fluid in a thermal conditioning system of a vehicle with an electric powertrain .

[0006] Known Art

[0007] In a thermal conditioning system of a vehicle with an electric powertrain, there are generally provided two or more evaporators , one of which - commonly referred to as cabin evaporator - provides for the thermal conditioning ( speci fically for the cooling) of the passenger compartment by means of a heat exchange between a refrigerant fluid which flows therethrough and a cabin air flow rate which hits it externally, while the ( at least one ) other - commonly referred to as battery evaporator - provides for the thermal conditioning of a high-voltage battery BATT of the vehicle , which supplies one or more electric traction motors of the powertrain of the vehicle . The battery evaporator is part of a heat exchange device , a so- called chiller, wherein the refrigerant fluid is in a heat exchange relation with a coolant which flows in a cooling circuit with liquid of the battery BATT itsel f , thanks to the action of one or more circulation pumps .

[0008] In the refrigeration cycle thermal conditioning systems there is a general need of a closed-loop control on the cooling performances , speci fically on the rotational speed of the compressor which processes the refrigerant fluid . However, said solutions perform a control in a rather simple fashion, which is generally unsatis factory due to the much wider control needs connected to the operability of a vehicle with an electric powertrain . Indeed, the cooling power of a refrigeration cycle thermal conditioning system for a vehicle with an electric powertrain may vary signi ficantly according to whether the cooling of the passenger compartment and / or of the battery BATT is active or inactive . With the control solutions of the known art , the risk of freezing of the cabin evaporator is very high when, for example , the cooling request of the battery BATT ceases suddenly and the rotational speed of the compressor is not adapted in an amount and with dynamics suf ficient to avoid the over-performance of the cabin evaporator, which at that point is the only evaporation device which has remained active .

[0009] Obj ect of the Invention

[0010] The invention aims at solving the technical problem described in the foregoing . Speci fically, the obj ect of the invention is controlling the rotational speed of the compressor of a refrigeration cycle thermal conditioning system of a vehicle with an electric powertrain in such a way as to increase the accuracy of the conditioning action with respect to the targets , and in such a way as to simultaneously avoid the occurrence of undesirable events when the thermal conditioning request varies , speci fically depending on whether a thermal conditioning is requested for the cabin, for the battery, for both or for neither of them .

[0011] Summary of the Invention

[0012] The obj ect of the invention is achieved by means of a method having the features set forth in the claims that follow, which form an integral part of the technical disclosure provided herein in relation to the invention .

[0013] Brief Description of the Figures

[0014] The invention will now be described with reference to the annexed Figures , which are provided by way of non-limiting example only and wherein :

[0015] - Figure 1 shows a general diagram of a cooling circuit whereon it is possible to implement a method according to the invention,

[0016] - Figures 2 to 5 show aspects of the circuit of Figure 1 ,

[0017] - Figure 6 shows a further diagram of a part of the cooling circuit of Figure 1 , and

[0018] - Figures 9 to 18 show implementation aspects of the method according to the invention .

[0019] Detailed Description

[0020] Figure 1 schematically shows the general structure of a cooling circuit CC whereon it is possible to implement a method according to the invention for closed-loop correction of a rotational speed of a compressor for refrigerant fluid in a thermal conditioning system of a vehicle with electric powertrain . As a general premise , every time the description refers to the flow rate of a fluid, such flow rate must be understood as a mass flow rate ( and therefore a reference is used having the prefix rh) irrespective of the fluid ( gas or liquid) under consideration, i f not explicitly dictated otherwise . Again, as a premise , every time reference is made to a "battery" (BATT ) of the vehicle , this must be understood - and the corresponding indication often appears throughout the description - as a high-voltage battery of the vehicle powertrain, which supplies the propulsive users of the vehicle ( for example the electric traction motors ) , and not as a low-voltage battery supplying ( some ) non-propulsive users of the vehicle .

[0021] The circuit CC comprises an electrically actuated compressor EAC, the delivery port whereof is in fluid communication with the inlet of a condenser CNDS . The condenser CNDS in a heat exchange relation with an air flow rate mAiR_cNDs which is partly supplied by a fan F arranged downstream of a set o f radiating elements , comprising the condenser CNDS and a radiator RAD ( the latter being arranged downstream of the condenser CNDS and upstream of the fan F, and partly supplied by the movement of the vehicle . The radiator RAD is part of a cooling circuit of traction elements of the vehicle powertrain, comprising one or more electric traction motors , respective inverters , the respective drivetrains which connect each motor to one or more corresponding wheels of the vehicle , and the oils of the drivetrains . The cooling circuit comprising the radiator RAD is traversed by a coolant flow rate which is processed by a circulation pump P_RAD . No other sections of said circuit are illustrated except for the pump P_RAD, the radiator RAD and the fan F, since the circuit is known in itsel f .

[0022] The outlet of the condenser CNDS is in fluid communication with a first circuit node Nl , which branches into two circuit branches , a first branch being directed towards the inlet of a cabin evaporator EVAP and a second branch being directed towards a second circuit node N2 , downstream whereof the second circuit branch divides into a third and a fourth circuit branch directed towards the inlet of a first cooling device ( speci fically a first chiller ) CHL1 and of a second cooling device ( speci fically a second chiller ) CHL2 . The cabin evaporator EVAP is in a heat exchange relation with a cabin air flow rate mAiR_cAB_EVAP which is processed and sent to the evaporator EVAP ( thus , it is supplied to the passenger compartment of the vehicle ) by means of a cabin blower BL .

[0023] Each of the chi llers CHL1 and CHL2 comprises a respective battery evaporator EV_B1 , EV_B2 (which receives a refrigerant fluid flowing in the circuit CC ) in a heat exchange relation with a heat trans fer fluid, speci fically a coolant flowing in a battery cooling circuit of the one or more batteries of the electric powertrain . By way of example , without implying any limitation, Figure 1 shows two cooling circuits of a high-voltage battery BATT which supplies one or more electric traction motors of the vehicle , wherein a first cooling circuit CL_B1 is in a heat exchange relation with the evaporator EV_B1 of the chiller CHL1 and comprises a first circulation pump CPI which processes a first coolant flow rate mcLN_cHLi, and a second cooling circuit CL_B2 is in a heat exchange relation with the evaporator EV_B2 of the chiller CHL2 , and comprises a second circulation pump CPI which processes a second coolant flow rate mcLN_cHL2 . The flow rates mcLN_cHLi and mcLN_cHL2 are in a heat exchange relation with the battery BATT for the thermal conditioning thereof , and they may be available individually or together as a function of the number of simultaneously active chillers . Referring to Figure 6 , it is moreover possible to envi sage a single cooling circuit common to both chillers CHL1 , CHL2 , and therefore a single circulation pump CP, either keeping both chillers CHL1 , CHL2 always active or deactivating one of them ( in this case , no thermal exchange will take place between the evaporator of the deactivated chiller and the battery cooling circuit ) , or alternatively a single chiller with a single battery cooling circuit . Always referring to Figure 6 , it is moreover possible to use the one or more chillers - CHL1 , CHL2 in the present case - for cooling further components of the high-voltage battery BATT , which are generally denoted herein as a first component CMP_1 and an n-th component CMP_N . Examples of components which may be cooled by means of the coolant circuit traversing the chillers comprise a converter DCDC on board the vehicle , a recharging device of the high- voltage battery BATT on board the vehicle , one or more inverters ( in combination with or as an alternative to the cooling by means of the radiator RAD) , one or more electric traction motors in combination or as an alternative to the cooling by means of the radiator RAD) , a heat exchanger (WTOC - Water Transmission Oil Cooler ) for a lubricant of the one or more drivetrains connecting each electric traction motor to the one or more drive wheels operatively associated therewith .

[0024] Upstream of the evaporator EVAP there is arranged an expansion / throttling valve TVX_EVAP, and upstream of the battery evaporators of the chillers CHL1 and CHL2 there are arranged respective expansion valves TXV_CHL1 and TXV_CHL2 . The expansion / throttling valves enable - by varying the respective hydraulic resistance as a function of the refrigerant fluid flow rate ( the refrigerant fluid being in the liquid phase when traversing such valves - in Figure 1 the valves are shown as variable hydraulic resistances ) - regulating the pressure of the refrigerant fluid at the inlets of the evaporator EVAP and of the battery evaporators EV_B1 , EV_B2 of the chillers CHL1 e CHL2 , so as to allow for a complete evaporation of the refrigerant fluid within them, preventing the compressor EAC from receiving a biphasic flow rate ( liquid+vapour ) . Upstream of each of the valves TXV_EVAP, TXV_CHL1 , TXV_CHL2 - i . e . upstream the respective evaporation devices ( the evaporator EVAP and the battery evaporators of the chillers CHL1 , CHL2 ) - there are arranged shut-of f valves SV_EVAP, SV_CHL1 , SV_CHL2 , respectively . The shut-of f valves SV_EVAP, SV_CHL1 , SV_CHL2 may alternatively be arranged between the corresponding valve TXV_EVAP, TXV_CHL1 , TXV_CHL2 and - respectively - the cabin evaporator EVAP, the battery evaporator of the chiller CHL1 and the battery evaporator of the chiller CHL2 ( in other words , what is important is that they be arranged respectively upstream of the evaporator EVAP and of the battery evaporators of the chillers CHL1 and CHL2 ) . The shutof f valves SV_EVAP, SV_CHL1 , SV_CHL2 each comprise a first open operating condition and a second closed operating condition, and they are normally in the open operating condition . The function of each of them is to exclude from the circuit CC the circuit branch downstream of the same , i . e . to exclude the evaporator EVAP and one or both battery evaporators of the chillers CHL1 and CHL2 according to needs ( thereby deactivating the respective chiller ) .

[0025] The outlet of the chillers CHL1 and CHL2 ( thus of the battery evaporators EV_B1 , EV_B2 of the chillers CHL1 , CHL1 ) converges into a third circuit node N3 and into a single f i fth circuit branch which converges , together with the section of the first circuit branch departing from the outlet of the cabin evaporator EVAP, into a fourth circuit node N4 downstream of which the cooling circuit CC closes at the delivery port of the compressor EAC .

[0026] The compressor EAC sends into the circuit CC a global refrigerant flow rate riiRFR_TOT in the vapour phase . The flow rate riiRFR_TOT traverses the condenser converting to the liquid phase and reaches the node Nl , whence it is divided between the cabin evaporator EVAP ( flow rate iiRFR_cAB_EVAP ) and the battery evaporators EV_B1 , EV_B2 of the chillers CHL1 and CHL2 (mRFR_cHL globally entering the node N2 , with the division of mRFR_cHLi for the evaporator EV_B1 and mRFR_cHL2 for the evaporator EV_B2 ) . The flow rates iiiRFR_cAB_EVAP and mRFR_cHL undergo evaporation ( at a substantially constant pressure ) within the battery evaporators EV_B1 , EV_B2 of the chillers CHL1 and CHL2 and the cabin evaporator EVAP, thereby cooling the coolant of the one or more batteries and the air of the passenger compartment , respectively . The flow rates mRFR_cAB_EVAP and mRFR_cHL in the vapour phase are mixed at node N4 into the flow rate mRFR_TOT, which is drawn back by the compressor EAC to enter the circuit CC again .

[0027] Generally speaking, in addition to the exemplary circuit configuration of Figure 1 , the method according to the invention may be applied to any refrigeration cycle thermal conditioning circuit of a vehicle , speci fically a vehicle with an electric powertrain, wherein the conditioning circuit comprises :

[0028] - a compressor (EAC in the circuit CC of Figure 1 ) having an intake port and a delivery port ,

[0029] - a condenser ( CNDS in the circuit CC of Figure 1 ) having an inlet in fluid communication with the delivery port of the compressor,

[0030] - at least two evaporation devices (EVAP, EV_B1 , EV_B2 for the circuit of Figure 1 ) having an inlet in fluid communication with an outlet of the condenser CNDS and an outlet in fluid communication with the intake port of the compressor EAC, the at least two evaporation devices being in a heat exchange relation with a respective heat trans fer fluid other than a refrigerant fluid circulating in the refrigeration cycle thermal conditioning circuit , wherein the at least two evaporation devices comprise a cabin evaporator (EVAP in Figure 1 ) for the thermal conditioning of a vehicle cabin, and wherein the heat trans fer fluid in a heat exchange relation with said cabin evaporator includes a cabin air flow rate supplied to the vehicle cabin, and wherein the at least two evaporation devices also include one or more battery evaporators ( EV_B1 , EV_B2 in Figure 1 ) of corresponding one or more chi llers ( CHL1 , CHL2 in Figure 1 ) for the thermal conditioning of the battery BATT of the electric powertrain of the vehicle , wherein said heat transfer fluid comprises a coolant of the battery BATT flowing in a circuit in a heat exchange relation with a corresponding battery evaporator (EV_B1 ) .

[0031] According to the invention, and with reference to the Figures 7 , 8 ( and generally 7 to 18 ) , the method comprises : determining a first temperature error ATAircabEvapErr for the cabin evaporator EVAP as a function of a di f ference between a current temperature value TAircabEvapout of the cabin air flow rate leaving said cabin evaporator and a reference temperature value of the cabin air f low rate mAiR_cAB_EVAP leaving said cabin evaporator EVAP, determining a second temperature error ATcintchiioutErr for one or more battery evaporators EV_B1 , EV_B2 of corresponding one or more chillers CHL1 , CHL2 as a function of a di f ference between a current temperature value Tcintchiiierout of the coolant flow rate mcLN_cHL at the outlet of the one or more chillers ( CHL1 , CHL2 for the circuit CC ) and a reference temperature value TcintchiiieroutTgt of the coolant flow rate mcLN_cHL at the outlet of said one or more chillers , - determining a global temperature error ATsrr as a function of said first and / or second temperature errors ATAircabEvapErr , ATcintchiioutErr and as a function of an activation state of the cooling of the vehicle cabin by means of said cabin evaporator (EVAP ) and of the cooling of the battery BATT by means of said one or more chillers ( CHL1 , CHL2 ) ,

[0032] - determining a correction of the rotational speed of the compressor EAC as a combination of an open-loop rotational speed correction nComP_0L_Tgt and of a closed- loop rotational speed correction nComP_cL_Tgt , said closed-loop rotational speed correction comprising a proportional rotational speed correction nComP_proPand an integral rotational speed correction nComP_int, the integral rotational speed correction nComP_int being defined as a function of an activation state of the cooling of the vehicle cabin by means of the cabin evaporator EVAP and of the cooling of the battery BATT by means of the one or more chillers ,

[0033] - storing the integral rotational speed correction nComp_int_strg i f a thermal conditioning is active only by means of the cabin evaporator EVAP or only by means of the one or more chillers , resetting the integral rotational speed correction ( request Intpeset) upon a transition from active to inactive of the activation state of the cooling of the vehicle cabin by means of said cabin evaporator EVAP and / or of the cooling of the battery BATT by means of the one or more chillers ( CHL1 , CHL2 ) , and determining the closed-loop rotational speed correction nComP_cL_Tgt as a function of the global temperature error ATsrr, of said storing the integral rotational speed correction nComP_int_strg, and of said resetting the integral rotational speed correction . The following Figures 9 to 17 show the preferred fashions for the deductions and the determinations which are performed in the method according to the invention, whereas Figure 18 shows the implementation thereof from a qualitative point of view .

[0034] Referring to Figure 9 , diagram 10 , the first temperature error ATAircabEvaPErr for the cabin evaporator EVAP is defined as a di f ference (block 12 ) between the current temperature value TAircabEvaPout of the cabin air flow rate mAiR_cAB_EvAp leaving the cabin evaporator EVAP and a reference value defined as the maximum (block 14 , MAX ) between a target temperature value TAircabEvapoutTgt of the cabin air flow rate mAiR_cAB_EvAp leaving the cabin evaporator EVAP and a minimum value TAircabEvapoutMin of the same cabin air flow rate mAiR_cAB_EvAp, wherein the minimum value TAircabEvaPoutMin corresponds to the temperature value at which ice forms on the outs ide of the evaporator EVAP due to the freezing of the moisture present in the air flow rate mAiR_cAB_EvAp ( so-called evaporator freezing) . Such a selection of the reference value is to be understood as a precautional measure aiming at avoiding the freezing of the moisture present in the air flow rate mAiR_cAB_EvAp on the outside of the evaporator, which condition would j eopardi ze the thermal comfort in the passenger compartment .

[0035] As a consequence - Figure 10 , diagram 20 - a maximum value ATAircabEvaPMax of the first error ATAircabEvapErr corresponds to a di f ference (block 22 ) between the current temperature value TAircabEvaPout of the cabin air flow rate mAiR_cAB_EvAp leaving the cabin evaporator EVAP and the minimum value TAircabEvapoutMin of the cabin air flow rate mAiR_cAB_EvAp itsel f .

[0036] Referring to Figure 11 , diagram 30 , the second temperature error ATcintchiiieroutErr for each battery evaporator EV_B1 , EV_B2 is determined as a function of a di f ference (block 32 ) between a current temperature value Tcintchiiierout ( Figura 6 ) of the coolant flow rate mcLN_cHL at the outlet of the set of chillers CHL1 , CHL2 ( generally of the at least one chiller ) and a reference temperature value corresponding to a target value TcintchiiierTgt of the coolant flow rate mCLN_cHL at the outlet of the set of chillers CHL1 , CHL2 ( generally of the at least one chiller ) .

[0037] The following Figure 12 , diagram 40 , shows a calculation of a combined temperature error ATcabBattcooiErr in conditions of combined ( simultaneous ) cooling of the passenger compartment and of the high- voltage battery BATT ( therefore , the activation state is "active" for both cooling functions ) . The calculation of the combined error ATcabBattcooiErr is the output data item of a switch SW40 controlled by a condition G40 , which corresponds to reaching a critical temperature of the high-voltage battery BATT

[0038] (Battery_Temperature_Critical = TRUE ) , and therefore to a temperature of the battery BATT equal to or higher than a critical temperature . Examples of values of critical temperature , which may vary depending on the applications and - last but not least - with respect to the features of the high-voltage battery BATT - may comprise values in the range of 48 ° C - 55 ° C ( inclusive ) . I f the battery BATT is not in conditions of critical temperature (Battery_Temperature_Critical TRUE , thus Battery_Temperature_Critical = FALSE ) , and therefore it has a temperature lower than the critical temperature , the output of the switch SW40 corresponds to a path alternative to the path shown in Figure 12 , and the error ATcabBattcooiErr is determined as the lower (block 42 , MIN) out of the maximum value ATAircabEvapMax of the first error ATAircabEvaPErr and the greater (block 44 , MAX ) out of the value of the first error ATAircabEvapErr and the value of the second error ATcintchiiieroutErr . In other words , i f the high-voltage battery BATT is not in a condition of critical temperature , the combined error ATcabBattcooiErr has an upper limit at the value ATAircabEvapMax, in order to prevent the moisture from freezing on the outside of the evaporator EVAP .

[0039] I f , on the contrary, the high-voltage battery BATT is in conditions of critical temperature (Battery_Temperature_Critical = TRUE ) , and therefore it has a temperature equal to or higher than the critical temperature , the output of the switch SW40 corresponds to the path shown in Figure 12 , and the error ATcabBattcooiErr is determined as the greater (block 46 , MAX ) out of the value of the first error ATAircabEvaPErr and the value of the second error ATcintchiiieroutErr . In other words , i f the high-voltage battery BATT is in conditions of critical temperature , the combined error ATcabBattcooiErr does not have an upper limit at the value ATAircabEvapMax , so as to favour the cooling of the battery BATT (with an increase of the cooling power expressed by the one or more chillers CHL1 , CHL2 , and therefore an increase of the rotational speed of the compressor EAC ) even when this may lead to the freezing of evaporator EVAP . This is due to the fact that the integrity of the high-voltage battery BATT is a target which has higher priority than the comfort in the passenger compartment , since temperatures above the critical temperatures may lead to so-called "venting" events of the battery BATT , which may potentially trigger a fire . In other words , in conditions of critical temperature of the battery BATT an undercooling in the one or more chillers CHL1 , CHL2 is permitted (which will probably result in a freez ing of the evaporator EVAP ) , while the undercooling in the evaporator EVAP is not permitted i f the temperature of the high-voltage battery BATT is not critical .

[0040] Figure 13 , diagram 50 , shows the calculation of the global temperature error ATErr as a function of the first and / or of the second temperature error ATAirCabEvapErr , ATclntChillerOutErr . The Calculation Of the global temperature error ATErr is the output data item of a first switch SW51 controlled by a condition G51 (AND) corresponding to the simultaneous occurrence ( as mentioned above, G51 corresponds to an AND block) of cooling of both the passenger compartment ( Cabin_Cooling_Active = TRUE , block G510 ) and of the high-voltage battery BATT (Battery_Cooling_Active = TRUE , blocl G511 ) . I f both conditions G510 Cabin_Cooling_Active = TRUE - and G511 Battery_Cooling_Active = TRUE - are veri fied, the global error ATErr is assigned the value of the combined error ATcabBattcooiErr determined as per Figure 12 .

[0041] I f at least one of the conditions G510 , G511 is not veri fied, the condition G50 is equally not veri fied, and the output of the switch SW51 corresponds to the path alternative to the one shown in Figure 13 . Such path corresponds to the output of a second switch SW52 controlled by a condition G520 identical to the condition G510 , and corresponding to the occurrence o f the cabin cooling ( Cabin_Cooling_Active = TRUE , block G520 ) . I f the condition G520 is veri fied ( Cabin_Cooling_Active = TRUE ) and the condition G51 is not veri fied ( and therefore, necessarily, Battery_Cooling_Active = / TRUE , thus

[0042] Battery_Cooling_Active = FALSE ) , then the global error ATErr is assigned the value of the first error ATAirCabEvapErr determined as per Figure 9 . I f the condition G520 is not veri fied, the output of the switch SW52 corresponds to the path alternative to the one shown in Figure 13 . Such path corresponds to the output of a third switch SW53 controlled by a condition G530 identical to the condition G511 , and corresponding to the occurrence of the cooling of the high-voltage battery BATT (Battery_Cooling_Active = TRUE , block G530 ) . I f the condition G530 is veri fied (Battery_Cooling_Active = TRUE ) and the condition G51 is not veri fied ( there fore , necessarily, Cabin_Cooling_Active TRUE , thus Cabin_Cooling_Active = FALSE ) , then the global error ATErr is assigned the second error ATcintchiiieroutErr determined as per Figure 11 . It should be noted that the cascade of the switches SW53 and SW52 is in any case excluded by the switch SW51 i f Cabin_Cooling_Active = TRUE and Battery_Cooling_Active = TRUE apply simultaneously, and therefore the conditions G520 and G530 practically correspond to instances of exclusive activation of the cooling either of the passenger compartment or of the high-voltage battery BATT , respectively . What has been described in the foregoing, moreover, demonstrates what has been previously stated, i . e . the fact that the global temperature error ATErr is defined as a function of the errors ATAircabEvaPErr , ATcintchiioutErr and of an activation state : the global temperature error ATErr may individually acquire the values of the one or of the other error, or else the combined value ATCabBattEvaPErr, which is anyway determined as a function of the errors ATAircabEvapErr , ATcintchiioutErr , and the discriminant for acquiring each value is the activation state of the cooling of the passenger compartment of the vehicle by means of the cabin evaporator EVAP and of the cooling of the battery BATT by means of the one or more chillers ( CHL1 , CHL2 ) .

[0043] As regards the storage of the integral correction nComp_int_strg , it is necessary first of all to refer to the Figures 2 , 3 , 4 , 5 and to the diagram of the circuit traversed by the coolant , which also flows through the chillers CHL1 , CHL2 . Figures 2 to 5 show in greater detail a few characteristics of the chillers CHL1 and CHL2 and of the evaporator EVAP, speci fically : each chiller CHL1 and CHL2 processes a refrigerant fluid flow rate iiiRFR_cHLi and iiiRFR_cHL2 through, respectively, the battery evaporators EV_B1 and EV_B2 , with mRFR_cHLi + mRFR_cHL2 = iiRFR_cHL and a coolant flow rate mcLN_GHLi and mCLN_cHL2 , respectively, with mCLN_cHLi + mcLN_cHL2 = iicLN_cHL ( Figure 6 ) . In the case of the cooling circuit with the arrangement according to the diagram of Figure 1 , the flow rates mcLN_cHLi e mcLN_cHL2 depend on the rotational speeds CPl_n and CP2_n of the pumps CPI and CP2 , whereas in the case of the cooling circuit with the arrangement according to the diagram of Figure 6 the flow rate mcLN_cHL depends on the rotational speed of the single pump CP ( see Figure 3 - the flow rates depend on the rotational speed of the circulation pumps also in the case of a single coolant circuit and a single circulation pump for both chillers ) and they enter the chillers CHL1 , CHL2 through respective inlet ports CHL1_IN, CHL2_IN ( each being equipped with a coolant temperature sensor TS_CLN_IN) , and then they flow out through outlet ports CHL1_OUT , CHL2_OUT ( each being equipped with a coolant temperature sensor TS_CLN_OUT ) , respectively;

[0044] - the cabin evaporator EVAP ( Figure 5 ) processes the refrigerant fluid flow rate mRFR_cAB_EVAP and it is hit by the cabin air flow rate mAiR_cAB_EVAP which hits the evaporator EVAP at an inlet section EVAP_IN and leaves it at an outlet section EVAP_OUT , therefore being in a heat exchange relation with the flow rate mRFR_cAB_EVAP in the transit from EVAP_IN to EVAP_OUT . The flow rate mAi R_CAB_EVAP depends on the rotational speed BL_n of the cabin blower BL ( Figure 5 ) . Always referring to the Figures 2 to 5 and to the diagram of Figure 6 , the cooling thermal powers EcabEvap , Echi which are currently being exchanged by the evaporator EVAP and by the one or more chillers CHL1 , CHL2 ( the latter to be understood as the number of active chillers , therefore one or more thereof ) may be expressed as a function of the mass flow rates of the respective heat trans fer fluids in a heat exchange relation therewith, and of the enthalpy di f ferences of the same heat trans fer fluids in the interaction with the evaporation devices EVAP, EV_B1 , EV_B2 , thus

[0045] EcabEvap = IIlAI R_CAB_EVAP ' Cp_AIR ' ( TAirCabEvapIn—TAirCabEvapOut ) Echll = mCLN_CHL ■ Cp_CLN ■ ( TclntChillerln—TclntChillerOut ) wherein :

[0046] EcabEvap is the thermal power exchanged by the cabin evaporator EVAP with the air supplied to the passenger compartment , i . e . it is the cooling thermal power output by the cabin evaporator EVAP,

[0047] Echi is the thermal power exchanged by the set of battery chillers EV_B1 , EV_B2 with the coolant traversing the chillers CHL1 , CHL2 ( generally, one or more active chillers ) , and therefore it is the cooling thermal power supplied by the one or more chillers , mAi R_CAB_EVAP is the mass flow rate of the cabin air which hits the evaporator EVAP in the transit from the inlet section EVAP_IN to the outlet section EVAP_OUT , mcLN_cHL is the coolant mass flow rate which transits through the set of the one or more chillers from the inlet to the outlet thereof , CP_AIR is the speci fic heat at constant pressure of air, CP_CLN is the speci fic heat at constant pressure of the coolant , TAircabEvapin is the air temperature at the inlet section EVAP_IN of the evaporator EVAP ( as detected by the sensor TS_AIR_IN) ,

[0048] TAircabEvapout is the air temperature at the outlet section EVAP_OUT of the evaporator EVAP ( as detected by the sensor TS_AIR_OUT ) ,

[0049] Tcintchiiierin is the coolant temperature at the inlet of the one or more chillers ( as detected by the sensor TS_CLN_IN) ,

[0050] Tcintchiiierout is the coolant temperature at the outlet of the one or more chillers ( as detected by the sensor TS_CLN_OUT ) .

[0051] It is therefore possible to define two power ratios which represent the cooling power fraction developed by the evaporator EVAP and by the set of the one or more chillers CHL1 , CHL2 ( the chillers which are active in the set ) with respect to the overall cooling power developed by the refrigeration cycle circuit ; particularly, for the evaporator EVAP, a first power ratio RcabEvap = EcabEvap / ( Echii + EcabEvap ) is defined, whereas for the set of the chillers CHL1 , CHL2 a second power ratio Rchii = Echii / (Echii + EcabEvap ) is defined .

[0052] Considering the power ratios RcabEvap and Rchii , it is possible to calculate the corresponding fractions of the integral correction of the rotational speed of the compressor EAC, which operate with respect to the evaporator EVAP and with respect to the set of the one or more chillers CHL1 , CHL2 ( the chillers which are active in the set ) . In this way, it is possible to separate a fraction from the other and, in the case of cooling the cabin (EVAP ) only or of cooling the high- voltage battery (BATT ) only, it is possible to operate only the fraction corresponding to the active cooling .

[0053] In other words , it is possible to express an integral correction nComp_int of the rotational speed of the compressor EAC as : ncomP_Int—ncomP_Int_Cab_EvaP+ ncomP_Int_Chll wherein nComP_int_cab_EvaPis a first fraction of the integral rotational speed correction nComP_int which operates with respect to the cooling by means of the cabin evaporator EVAP, and nComP_int_chii is a second fraction of the integral rotational speed correction nComP_int which operates with respect to the cooling by means of the set of the one or more chillers CHL1 , CHL2 ( the chillers which are active in the set ) . As a function of the power ratios RcabEvaPe Rchii it is possible to write ncomP_Int_Cab_EvaP—RcabEvaP‘ ncomP_Int ncomP_Int_Chll—Rchll " ncomP_Int

[0054] With reference to Figure 14 , diagram 60 , the sequence is shown of the steps which lead to storing the integral correction nComP_int_strg. The storage o f the integral correction nComP_int_strgis the output data item of a first switch SW61 controlled by a condition G61 (AND) corresponding to the simultaneous occurrence of an absence of the passenger compartment cooling ( Cabin_Cooling_Active = FALSE , block G610 ) and of an absence of the cooling of the high-voltage battery BATT (Battery_Cooling_Active = FALSE , block G611 ) . I f both conditions G610 - Cabin_Cooling_Active = FALSE - and G611 - Battery_Cooling_Active = FALSE - are veri fied, the integral correction nComP_int_strgwhich is stored is equal to the zero value , block 613 (" 0" ) .

[0055] I f at least one of the conditions G610 , G611 is not veri fied, i . e . i f at least one out of the cabin cooling ( Cabin_Cooling_Active = TRUE ) and the cooling of the high-voltage battery BATT

[0056] (Battery_Cooling_Active = TRUE ) is active , the condition G61 is not veri fied, and the output of the switch SW61 corresponds to the path alternative to the one shown in Figure 14 . Such a path corresponds to the output of a second switch SW62 controlled by a condition G620 identical to the condition G610 and corresponding to an absence of the cabin cooling ( Cabin_Cooling_Active = FALSE , block G620 ) . I f the condition G620 is veri fied ( Cabin_Cooling_Active = FALSE ) and the condition G61 is not veri fied ( and therefore , necessarily, Battery_Cooling_Active = TRUE - the cooling of the high-voltage battery BATT is active ) , then the integral correction nComP_int_strgwhich is stored is equal to nComP_int_chii , which is determined as a function of the power ratio Rchii as described in the foregoing .

[0057] I f the condition G620 i s not veri fied, the output of the switch SW62 corresponds to the path alternative to the one shown in Figure 14 . Such a path corresponds to the output of a third switch SW63 controlled by a condition G630 identical to the condition G611 and corresponding to the absence of the cooling of the high-voltage battery BATT (Battery_Cooling_Active = FALSE , block G630 ) . I f the condition G630 is veri fied (Battery_Cooling_Active = FALSE ) and the condition G61 is not veri fied ( therefore , necessarily, Cabin_Cooling_Active = TRUE , and thus the cabin cooling is active ) , then the integral correction nComP_int_strgwhich is stored is equal to nComP_cab_EvaP, which is determined as a function of the power ratio Rcab_EvaPas described in the foregoing . I f , on the contrary, the condition Battery_Cooling_Active = TRUE is veri fied, necessarily in combination with Cabin_Cooling_Active = TRUE ( otherwise the switch SW63 would not act ) , the output of the switch SW63 is the path alternative to the one shown in Figure 14 , and corresponds to the zero value, block 631 ("0") , in the same way as in the absence of cooling of the passenger compartment or of the high-voltage battery BATT (block 613) .

[0058] In other words, in a condition of activation of the cooling of the passenger compartment only or of the cooling of the battery BATT only, the stored integral correction mirrors the type of cooling which is currently active. If both coolings are active or neither is, the integral correction nComP_int_strg which is stored equals the zero value.

[0059] With reference to Figure 15, diagram 70, there is shown the sequence of the steps which lead to a reset of the stored integral correction by means of a reset request IntReset. The reset request is the output data item of a logical block 71 of the "OR" type, and it corresponds to the occurrence of at least one (and / or, as already mentioned) of the following instances:

[0060] - both conditions (block 72, "AND") as per blocks 73, 74 are verified, which correspond to input data for block 72, specifically the fact that at the previous calculation iteration the cooling of the high-voltage battery BATT was active (Battery_Cooling_Active_01d = TRUE, block 73) , and the fact that at the current calculation iteration the cooling of the high-voltage battery BATT (Battery_Colling_Active = FALSE) is no longer active. If the logic state of the block 72 is "1", therefore, this means that a transition has taken place of the activation state of the cooling of the high-voltage battery BATT from active (block 73) to inactive (block 74) ;

[0061] - both conditions (block 75, "AND") as per blocks 76, 77 are verified, which correspond to input data for block 75, specifically the fact that at the previous calculation iteration the cooling of the passenger compartment (Cabin_Cooling_Active_01d = TRUE, block 76) was active , and the fact that at the current calculation iteration the cooling of the passenger compartment ( Cabin_Colling_Active = FALSE ) is no longer active . I f the logic state of the block 75 is " 1" , therefore , this means that a transition has taken place of the activation state of the cooling of the passenger compartment from active (block 76 ) to inactive (block 77 ) .

[0062] In other words , every time a transition takes place from an active to an inactive state of the cooling of the passenger compartment or of the high- voltage battery BATT , a reset request IntReset is sent , and the stored integral correction value is reset and re-initiali zed to the value nComP_int_strg, which is determined as described with reference to Figure 14 , i . e . to the value of integral correction which reflects the current condition of the cooling activity .

[0063] With reference to the Figures 16 , 17 , they show the closed-loop calculation of the correction nComP_cL_Tgt of the rotational speed of the compressor EAC . Figure 16 , diagram 80 , shows the calculation of a maximum rotational speed nComP_Max which corresponds to the minimum value (block 82 , MIN) out of the value of a first maximum rotational speed nComP_Max_Pwr determined as a function of a limit of absorption of electric power by the compressor EAC and the value of a second maximum rotational speed nComP_Max_NVH determined as a function of a noise emission limit by the compressor EAC . A preferred solution for determining nComP_Max_NVH is described in the Patent Application for Industrial Invention n . 102024000004615 in the name of the same Applicant , but in any case it is possible to extrapolate the value of nComP_Max_NVH from a map which uses , as input data, for example , an advancement speed of the vehicle and a cooling power request for the thermal conditioning of the passenger compartment and / or of the high-voltage battery BATT ( in the same way as a map-based calculation is possible for the value nComp_ _Max_Pwr ) •

[0064] With reference to Figure 17 , diagram 90 , it shows the diagram of a controller for a closed-loop calculation of the ( target ) correction nComP_cL_Tgt of the rotational speed of the compressor EAC . The calculation of the correction nComP_cL_Tgt , speci fically, is operated by means of a proportional-integral controller 92 which operates as a function of the global temperature error ATsrr , of the stored integral correction value nComP_int_strg and o f the reset request of the correction value Intpeset, the latter ones operating according to the fashion described in the foregoing .

[0065] The controller 92 comprises an upper saturation limit 93 equal to a di f ference (block 94 ) between the maximum rotational speed value nComP_Max of the compressor EAC and a target rotational speed nComP_0L_Tgt of the compressor EAC, determined in open loop ( the upper saturation limit , therefore , corresponds to the available margin for the closed- loop correction, which is in turn distributed between proportional correction nComP_ProP_Tgt and integral correction nComP_int_Tgt, thus ncomP_CL_Tgt = ncomP_ProP_Tgt + ncomP_Int_Tgt ) , and a lower saturation limit 95 corresponding to the opposite ( — nComP_0L_Tgt ) of the target rotational speed value determined in open loop nComP_0L_Tgt ( in this way, the closed-loop correction can at most annul the rotational speed of the compressor determined in open loop, but cannot lead to an inversion of the rotation direction of the compressor .

[0066] As already stated in the foregoing, any time a transition takes place from the active to the inactive state of the cooling of the passenger compartment or of the high-voltage battery BATT , a reset request IntReset is sent , and the stored integral correction value is reset and re-initiali zed to the value nComP_int_strgdetermined as described with reference to Figure 14 , i . e . to the integral correction value which reflects the current condition of the cooling activity .

[0067] The following Figure 18 graphically shows , diagram 100 , a qualitative example of the evolution in time ( t on the X-axis ) of the integral correction nComP_int during a transition from a combined cooling of the cabin and of the high-voltage battery BATT - reference B+C - to a condition of cabin cooling only - reference C . As can be observed, thanks to the method according to the invention, the integral rotational speed correction nComP_int of the compressor EAC immediately adapts to the modi fied cooling condition - see the disappearance of the correction fraction nComP_int_chii after deactivating the chillers ) , thereby avoiding the problem of freezing on the evaporator EVAP and, generally, a sensation of reduced comfort in the passenger compartment , together with an accuracy which is guaranteed by the closed-loop control based on the global temperature error ATErr, which in turn adapts to the new cooling condition, according to what has been illustrated and described with reference to Figure 13 .

[0068] Of course , the implementation details and the embodiments may amply vary with respect to what has been described and illustrated herein without departing from the extent of the present invention, as defined in the annexed claims .

Claims

CLAIMS1. A method for the closed-loop correction of a rotational speed of a compressor (EAC) for refrigerant fluid in a refrigeration cycle thermal conditioning circuit (CC) of a vehicle with an electric powertrain, the thermal conditioning circuit (CC) comprising:- a compressor (EAC) having an inlet port and a delivery port, a condenser (CNDS) having an inlet in fluid communication with the delivery port of the compressor (EAC) ,- at least two evaporation devices (EVAP, EV_B1, EV_B2) having an inlet in fluid communication with an outlet of the condenser (CNDS) and an outlet in fluid communication with the inlet port of the compressor, said at least two evaporation devices (EVAP, EV_B1, EV_B2) being in a heat exchange relation with a respective heat transfer fluid other than a refrigerant fluid circulating in the refrigeration cycle thermal conditioning circuit (CC) , where said at least two evaporation devices (EVAP, EV_B1, EV_B2) include a cabin evaporator (EVAP) for the thermal conditioning of a vehicle cabin, and wherein the heat transfer fluid in heat exchange relation with said cabin evaporator includes a cabin air flow rate (mAIR_CAB_EVAP) supplied to the vehicle cabin, wherein said at least two evaporation devices also include one or more battery evaporators (EV_B1, EV_B2) of corresponding one or more chillers (CHL1, CHL2) for the thermal conditioning of a battery (BATT) of the electric powertrain of the vehicle, and wherein said heat transfer fluid comprises a coolant of said battery (BATT) flowing in a circuit in heat exchange relation with a corresponding battery evaporator (EV_B1) , the method comprising:determining a first temperature error (ATAirCabEvapErr) for said cabin evaporator (EVAP) as a function of a difference (12) between a current temperature value ( TAirCabEvapOut ) of the cabin air flow rate leaving said cabin evaporator and a reference temperature value of the cabin air flow rate (iiAiIR_CAB_EVAP) leaving said cabin evaporator (EVAP) , determining a second temperature error (ATClntChllOutErr ) for one or more battery evaporators (EV_B1, EV_B2) of corresponding one or more chillers (CHL1, CHL2) as a function of a difference (32) between a current temperature value ( TClntChillerOut ) of the coolant flow rate (mCLN_CHL) at the outlet of said one or more chillers (CHL1, CHL2) and a reference temperature value ( TClntChillerOutTgt ) of the coolant flow rate (mCLN_CHL) at the outlet of said one or more chillers (CHL1, CHL2) ,- determining an overall temperature error (ATErr) as a function of said first and / or second temperature errors (ATAirCabEvapErr, TAirCabEvapOut) and as a function of an activation state of the cooling of the vehicle cabin by means of said cabin evaporator (EVAP) and of the cooling of the battery (BATT) by means of said one or more chillers (CHL1, CHL2) ,- determining a correction of the rotational speed of the compressor (EAC) as a combination of an openloop rotational speed correction (nComp_OL_Tgt ) and a closed-loop rotational speed correction (nComp_CL_Tgt ) , said a closed-loop rotational speed correction comprising a proportional rotational speed correction (nComp_Prop) and an integral rotational speed correction (nComp_Int) , the integral rotational speed correction (nComp_Int) being defined as a function of the activation state of the cooling of the vehicle cabin by means of the cabin evaporator (EVAP) and ofthe cooling of the battery (BATT) by means of said one or more chillers (CHL1, CHL2) ,- storing the integral rotational speed correction (nComp_Int_Strg) if a thermal conditioning is active only by means of the cabin evaporator (EVAP) or only by means of said one or more chillers (CHL1, CHL2) , resetting the integral rotational speed correction (IntReset) upon a transition from active to inactive of the activation state of the cooling of the vehicle cabin by means of said cabin evaporator (EVAP) and / or (71) of the cooling of the battery (BATT) by means of said one or more chillers (CHL1, CHL2) , and determining said closed-loop rotational speed correction (nComp_CL_Tgt ) as a function of said overall temperature error (ATErr) , said storing the integral rotational speed correction (nComp_Int_Strg) , and of said resetting the integral rotational speed correction ( IntReset ) .

2. The method of claim 1, wherein the reference temperature value ( TClntChillerOutTgt ) of the coolant flow rate (mCLN_CHL) at the outlet of said one or more chillers (CHL1, CHL2) is a target value of the temperature of the coolant flow rate (mCLN_CHL) at the outlet of said one or more chillers (CHL1, CHL2) .

3. The method of claim 1 or claim 2, further including defining (20) a maximum value(ATAirCabEvapMax) of the first error (ATAirCabEvapErr ) as a difference (22) between the current temperature value ( TAirCabEvapOut ) of the cabin air flow rate (mAIR_CAB_EVAP) leaving the cabin evaporator (EVAP) and a minimum temperature value ( TAirCabEvapOutMin) of the cabin air flow rate (mAIR_CAB_EVAP) , said minimum temperature value corresponding to a temperature value at which ice forms on the outside of the evaporator (EVAP) due to the freezing of the moisture present inthe cabin air flow (mAIR_CAB_EVAP) .

4. The method of claim 3, further including the calculation of a combined temperature error (ATCabBattCoolErr) upon an active activation state of the colling of the vehicle cabin by means of said cabin evaporator (EVAP) and of the cooling of the battery (BATT) by means of said one or more chillers (CHL1, CHL2) , said combined temperature error ATCabBattCoolErr being calculated as: the lower (42) among said maximum value (ATAirCabEvapMax) of the first temperature error (ATAirCabEvapErr ) and the greater (44) of the value of the first temperature error (ATAirCabEvapErr) and the value of the second temperature error (ATClntChillerOutErr ) if the battery (BATT) has a temperature below a critical temperature (Battery_Temperature_Critical = FALSE) ,- the greater (46) among the value of the first temperature error (ATAirCabEvapErr) and the value of the second temperature error (ATClntChillerOutErr) if said battery (BATT) has a temperature equal to or higher than said critical temperature (Battery_Temperature_Critical = TRUE) .

5. The method of claim 4, wherein said determining a global temperature error (ATErr) includes:- assigning (SW51) to the global temperature error (ATErr) the value of said combined temperature error (ATCabBattCoolErr) if both the cooling of the vehicle cabin (Cabin_Cooling_Active = TRUE) by means of said cabin evaporator (EVAP) and the cooling of the battery (Battery_Cooling_Active = TRUE) by means of said one or more chillers (CHL1, CHL2) are active,- assigning (SW52) to the global temperature error (ATErr) the value of said first temperature error (ATAirCabCoolErr ) if only the cooling of the vehiclecabin by means of said cabin evaporator (EVAP) is active (Cabin_Cooling_Active = TRUE) , while the cooling of the battery by means of said one or more chillers (CHL1, CHL2) is inactive (Battery_Cooling_Active = FALSE) ,- assigning (SW53) to the global temperature error (ATErr) the value of said second temperature error ATClntChillerOutErr ) if only the cooling of the battery by means of said one or more chillers (CHL1, CHL2) is active (Battery_Cooling_Active = TRUE) , while the cooling of the vehicle cabin by means of said cabin evaporator (EVAP) is inactive (Cabin_Cooling_Active = FALSE) .

6. The method of Claim 5, further including assigning (SW53) to the global temperature error (ATErr) a zero value (531) if both the cooling of the vehicle cabin (Cabin_Cooling_Active = FALSE) by means of said cabin evaporator (EVAP) and the cooling of the battery (Battery_Cooling_Active = FALSE) by means of said one or more chillers (CHL1, CHL2) are inactive.

7. The method of any of the above claims, including defining a first power ratio RCabEvap for said cabin evaporator (EVAP) and a second power ratio RChll for said at least one chiller (CHL1, CHL2) , wherein, named:- ECabEvap a cooling thermal power output by the cabin evaporator (EVAP) ,- EChll a cooling thermal power output by the one or more chillers (CHL1, CHL2) , the first power ratio is defined as a ratio ECabEvap / (EChll+ECabEvap) , and the second power ratio is defined as a ratio EChll / (EChll+ECabEvap) , the method further including:- defining a first fraction nComp_Int_Cab_Evap of said integral rotational speed correction (nComp_Int)operating with respect to the cooling by means of the cabin evaporator (EVAP) according to the relation nComp_Int_Cab_Evap = RCabEvap • nComp_Int , and defining a second fraction nComp_Int_Chll of said integral rotational speed correction (nComp_Int) operating with respect to the cooling by means of said one or more chillers (CHL1, CHL2) according to the relation nComp_Int_Chll = RChll • nComp_Int , where nComp_Int is said integral rotational speed correction .

8. The method of claim 7, wherein said storing the integral rotational speed correction (nComp_Int_Strg) includes : storing (SW61) an integral rotational speed correction (nComp_Int_Strg) equal to a zero value (613) if both the cooling of the vehicle cabin (Cabin_Cooling_Active = FALSE) by means of said cabin evaporator (EVAP) and the cooling of the battery (Battery_Cooling_Active = FALSE) by said one or more chillers (CHL1, CHL2) are inactive, storing (SW62) an integral rotational speed correction (nComp_Int_Strg) equal to said second fraction nComp_Int_Chll if the cooling of the vehicle cabin by means of said cabin evaporator (EVAP) is inactive (Cabin_Cooling_Active = FALSE) , and if the cooling of the battery by means of said one or more chillers (CHL1, CHL2) is active (Battery_Cooling_Active = TRUE) , storing (SW63) an integral rotational speed correction (nComp_Int_Strg) equal to said first fraction nComp_Int_Cab_Evap if the cooling of the vehicle passenger compartment by means of said cabin evaporator (EVAP) is active (Cabin_Cooling_Active = TRUE) , and if the cooling of the battery by means of said one or more chillers (CHL1, CHL2) is inactive(Battery_Cooling_Active = FALSE ) , storing ( SW63 ) an integral rotational speed correction (nComp_Int_Strg) equal to a zero value ( 631 ) i f both the cooling of the vehicle cabin( Cabin_Cooling_Active = TRUE ) by means of said cabin evaporator (EVAP ) and the cooling of the battery (Battery_Cooling_Active = TRUE ) by said one or more chillers ( CHL1 , CHL2 ) are inactive .

9. The method of claim 7 or claim 8 , wherein the thermal cooling power ECabEvap output by the cabin evaporator (EVAP ) is determined according to the relationship :ECabEvap mAIR_CAB_EVAP • cp_AIR • ( TAirCabEvapInTAirCabEvapOut ) wherein : mAIR_CAB_EVAP is the mass flow rate of the cabin air flow rate that hits the cabin evaporator (EVAP ) in the transit from an inlet section (EVAP_IN) to an outlet section thereof (EVAP_OUT ) , cp_AIR is the speci fic heat at constant pressure of air TAirCabEvapIn is the air temperature at the inlet section (EVAP_IN) of the cabin evaporator (EVAP ) , TAirCabEvapOut is the air temperature at the outlet section (EVAP_OUT ) of the cabin evaporator (EVAP ) , and wherein the thermal cooling power EChll output the by one or more chillers ( CHL1 , CHL2 ) is determined according to the relationship :EChll mCLN_CHL • cp_CLN • ( TClntChillerlnTClntChi 11 erOut ) where : mCLN CHL is the mass flow rate of coolant that flowsthrough the complex of the one or more chillers (CHL1, CHL2) from the inlet to the outlet thereof cp_CLN is the specific heat at constant pressure of the coolantTClntChillerln is the temperature of the coolant at the inlet of the one or more chillers (CHL1, CHL2) , TClntChillerOut is the temperature of the coolant at the outlet of the one or more chillers (CHL1, CHL2) .

10. The method of any of the above claims, wherein said closed-loop rotational speed correction (nComp_CL_Tgt ) is determined by means of a proportional-integral controller (92) operating as a function of the global temperature error (ATErr) , of a stored integral rotational speed correction value (nComp_Int_Strg) and of a reset of the stored rotational speed correction value (IntReset) , the proportional-integral controller (92) including an upper saturation limit (93) equal to a difference (94) between a maximum rotational speed value (nComp_Max) of the compressor (EAC) and a target rotational speed of the compressor (EAC) determined in open loop (nComp_OL_Tgt) , and a lower saturation limit (95) corresponding to the opposite ( -nComp_OL_Tgt ) of the value of the target rotational speed of the compressor (EAC) determined in open loop (nComp_OL_Tgt ) .

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