Method for controlling a thermal regulation system

Abstract

The invention relates to a method for controlling a thermal conditioning system (100) comprising: a heat transfer fluid circuit (20); a refrigerant circuit (10) having: an electric compressor (7); a first heat exchanger (1) configured to deliver thermal power (Pw1) to the heat transfer fluid (F1); a first pressure reducer (31); a second heat exchanger (2); a bypass branch (B) for returning refrigerant at the outlet of the compressor (7) to the second exchanger (2) and the second pressure reducer (32), the method comprising the steps of: (i) receiving a thermal power setpoint (CPw) for thermal power delivered to the at least one heat transfer fluid (F1); (ii) determining an electrical setpoint (CPwel) for electrical power delivered to the compressor (7); (iv) determining a suction pressure setpoint (CPrs) of the compressor (7); (vi) controlling the flow cross section of the second pressure reducer (32) such that the suction pressure (Ps) of the compressor (7) equals the determined suction pressure setpoint (CPrs); (vii) controlling the flow cross-section of the first pressure reducer (331) such that the refrigerant at the inlet of the compressor (7) is in a superheated vapor state.

Description

Technical Field

[0001] The invention relates to the field of thermal regulation systems. Such thermal regulation systems can be installed in particular on motor vehicles. If the vehicle has an electric drive train, these systems make it possible to thermally regulate various components of the vehicle, such as the vehicle interior or an electrical energy storage battery. The heat exchange is mainly managed by compression and expansion of a refrigerant fluid in a plurality of heat exchangers. Background Art

[0002] Heat conditioning systems usually utilize a refrigerant fluid circuit and a heat transfer liquid circuit for exchanging heat with the refrigerant fluid. Such systems are therefore referred to as indirect. The compressor brings the refrigerant fluid to a high pressure.

[0003] It is known practice to arrange in series in a refrigerant fluid circuit a first heat exchanger for heating the air flow intended for the vehicle interior, a second heat exchanger for heating an element of the vehicle's drive train, such as an electrical energy storage battery, and a third heat exchanger for cooling the element of the vehicle's drive train. Depending on the operating mode, it is thus possible to supply heat to an element of the vehicle's drive train in order to heat the element, or to collect heat from the element in order to transfer the heat to, for example, the air flow supplied to the vehicle interior in order to heat the latter.

[0004] When the vehicle is started at a colder ambient temperature, it is desirable to ensure that the temperature inside the vehicle rises quickly in order to ensure good thermal comfort for the passengers. To this end, it is known to provide a bypass branch to the refrigerant fluid circuit, which allows the refrigerant fluid leaving the compressor to reach the third exchanger without passing through the first exchanger or the second exchanger. The high-pressure refrigerant fluid flow at the outlet of the compressor is divided into a flow circulating in the main loop and a flow circulating in the bypass branch. After having passed through the third heat exchanger, all refrigerant fluid flows arrive at the inlet of the compressor. This special thermodynamic cycle makes it possible to increase the flow rate of the refrigerant fluid circulating in the circuit, thereby increasing the amount of energy received by the refrigerant fluid when being compressed. The temperature rise of the refrigerant fluid is therefore accelerated.

[0005] This operating mode makes it possible to ensure an accelerated rise in temperature inside the vehicle, but generally entails difficulties in controlling the operation of the compressor and the corresponding circulation of the fluid in the main circuit and in the bypass branch.

[0006] Therefore, there is a need for an optimized control method for such a thermal regulation system. Summary of the invention

[0007] To this end, the present invention proposes a method for controlling a heat regulation system, the heat regulation system comprising:

[0008] - a heat transfer liquid circuit, configured to circulate a heat transfer liquid,

[0009] - A refrigerant fluid circuit having:

[0010] --The main loop, in the direction of flow of the refrigerant fluid, includes:

[0011] ---a compressor, configured to be driven by an electric motor, the compressor configured to transform the refrigerant fluid from an intake pressure to a delivery pressure,

[0012] ---a first heat exchanger, configured to provide thermal power to the heat transfer fluid,

[0013] ---First expansion valve,

[0014] ---a second heat exchanger, arranged jointly on the refrigerant fluid circuit and the heat transfer liquid circuit, so as to receive thermal power (Pw2) from the heat transfer liquid,

[0015] a first bypass branch allowing the refrigerant fluid at the outlet of the compressor to reach the second exchanger by bypassing the first exchanger and the first expansion valve, the first bypass branch comprising the second expansion valve,

[0016] The control method comprises the following steps:

[0017] (i) receiving a thermal power set point for a thermal power to be provided to a heat transfer fluid at least at a first exchanger,

[0018] (ii) determining an electric power set point for the electric power to be supplied to the electric motor of the compressor based on the received thermal power set point for the thermal power to be supplied and on the thermal power received by the second exchanger,

[0019] (iii) determining a delivery pressure set point based on the determined electrical power set point and based on the maximum delivery pressure,

[0020] (iv) determining an intake pressure set point based on the determined electric power set point and based on the determined delivery pressure set point,

[0021] (v) controlling the speed of the electric motor of the compressor so that the electric power supplied to the compressor is equal to the determined set point,

[0022] (vi) controlling the passage cross section of the second expansion valve so that the intake pressure of the compressor is equal to the determined intake pressure set point,

[0023] (vii) The passage cross section of the first expansion valve is controlled so that the refrigerant fluid at the inlet of the compressor is in a superheated vapor state.

[0024] This control structure makes it possible to robustly control the amount of refrigerant fluid circulating in the refrigerant fluid circuit, as well as the distribution of the refrigerant fluid flow between the flow circulating in the main loop and passing through the first exchanger and the flow circulating in the first bypass branch and merging with the flow of the main branch downstream of the first expansion valve.

[0025] The functions listed in the following paragraphs may be implemented independently of each other or in any technically feasible combination:

[0026] According to an exemplary embodiment, the heat conditioning system is a heat conditioning system for a motor vehicle.

[0027] According to one embodiment, in step (ii), the set point of the electric power to be supplied to the electric motor of the compressor is equal to the set point of the received thermal power to be supplied minus the thermal power received by the second exchanger.

[0028] According to one embodiment, in step (iv), the intake pressure set point is determined based on the electrical power set point, on the determined delivery pressure set point and on the maximum permissible rotational speed of the compressor.

[0029] The maximum permissible speed may depend on operating conditions. In particular, the maximum permissible speed may depend on the forward speed of the vehicle. Thus, the maximum permissible speed when the vehicle is moving may be higher than the maximum permissible speed when the vehicle is stopped.

[0030] The maximum delivery pressure may be a constant value, for example 27 bar.

[0031] The maximum delivery pressure may correspond to a maximum permissible pressure which ensures the long-term reliability of the compressor.The use of a constant value makes it possible to simplify the control method.

[0032] According to one embodiment of the method, the set point for the electric power to be supplied to the electric motor of the compressor is, for example, equal to the received total heating power set point.

[0033] According to a variant, the setpoint for the electric power to be supplied to the electric motor of the compressor may be equal to the received total heating power setpoint divided by the adiabatic efficiency of the compressor.

[0034] Therefore, the electrical power set point can be calculated more accurately.

[0035] According to one embodiment of the method, the passage cross section of the first expansion valve is controlled by a proportional-integral controller.

[0036] Similarly, the passage cross section of the second expansion valve may be controlled by a proportional-integral controller.

[0037] This type of controller ensures robust control while still being easy to program and fine-tune.

[0038] According to one embodiment of the method, the control of the passage cross section of the first expansion valve and the control of the passage cross section of the second expansion valve are configured such that:

[0039] - an increase in the channel cross section of the first expansion valve leads to a decrease in the channel cross section of the second expansion valve,

[0040] An increase in the channel cross section of the second expansion valve results in an increase in the channel cross section of the first expansion valve.

[0041] The coupling between the correction of the passage cross section of the first expansion valve and the correction of the passage cross section of the second expansion valve makes it possible to increase the control stability.

[0042] According to one embodiment of the method, in which the primary loop of the refrigerant fluid circuit comprises a third expansion valve, which is arranged downstream of the compressor and upstream of the first heat exchanger, the method comprises the following steps:

[0043] (viii) controlling the refrigerant fluid passage cross section in the third expansion valve so that the delivery pressure is equal to the determined delivery pressure set point.

[0044] To this end, step (viii) comprises the following sub-step: determining the delivery pressure (Pr_d).

[0045] Ensuring partial expansion of the refrigerant fluid in the third expansion valve forces the compressor to compress the refrigerant fluid to a value higher than the condensing pressure in the first exchanger. The thermal power received by the refrigerant fluid is thus increased and this makes it possible to accelerate the temperature rise of the thermal conditioning system.

[0046] According to one embodiment, the method comprises the following steps:

[0047] (vii1) determining the superheat of the refrigerant fluid at the inlet of the compressor,

[0048] (vii2) Controlling the passage cross section of the first expansion valve so that the superheat of the refrigerant fluid at the inlet of the compressor is equal to the set point value.

[0049] The superheat set point at the compressor inlet is selected to ensure that the refrigerant sucked into the compressor is completely in gaseous form. This ensures the reliability of the compressor.

[0050] The superheat set point value of the refrigerant fluid at the compressor inlet is, for example, 5°C to 15°C.

[0051] According to one embodiment, the method comprises the following steps:

[0052] (vii1) determining the superheat of the refrigerant fluid at the outlet of the compressor,

[0053] (vii2) Controlling the passage cross section of the first expansion valve so that the superheat of the refrigerant fluid at the outlet of the compressor is equal to the set point value.

[0054] Controlling the superheat set point at the compressor outlet is another way of ensuring that the refrigerant sucked into the compressor is essentially entirely in gaseous form. This ensures compressor reliability.

[0055] The superheat set point value of the refrigerant fluid at the compressor outlet is 15°C to 35°C.

[0056] According to one embodiment of the method, the main circuit of the heat regulation system comprises a third heat exchanger downstream of the first heat exchanger and upstream of the first expansion device, the third heat exchanger being arranged jointly on the refrigerant fluid circuit and the heat transfer liquid circuit so as to be able to exchange heat between the refrigerant fluid and the heat transfer liquid, the third heat exchanger being configured to provide thermal power to the heat transfer liquid, wherein in step (i),

[0057] The thermal power set point of the thermal power to be provided is the total thermal power which is the sum of the thermal power to be provided to the heat transfer fluid at the first exchanger and the thermal power to be provided to the heat transfer liquid at the third exchanger.

[0058] According to an exemplary embodiment of the method, the heat transfer fluid is an air flow in the interior of the motor vehicle.

[0059] According to an exemplary embodiment of the method, the heat transfer fluid is a heat transfer liquid configured to circulate in a fifth heat exchanger, the fifth heat exchanger being configured to exchange heat with an air flow inside the vehicle.

[0060] According to an embodiment of the method, the second heat exchanger is thermally coupled to the element of the vehicle drive train via a heat transfer liquid in a heat transfer liquid circuit.

[0061] The second heat exchanger thus makes it possible to absorb heat from an element of the vehicle's drive train in order to keep its temperature within an acceptable range, or to transfer the absorbed heat to another component.

[0062] According to an embodiment of the method, the third heat exchanger is thermally coupled to an element of the drive train of the vehicle via a heat transfer liquid in the heat transfer liquid circuit.

[0063] The third heat exchanger thus makes it possible to supply thermal power to an element of the vehicle drive train, that is to say to heat the element in order to increase its temperature.

[0064] Elements of the electric drive train include, for example, the vehicle's electric traction motor.

[0065] In a variant or in addition, the elements of the electric drive train include an electronic module for operating an electric traction motor of the vehicle.

[0066] In another variation or in addition, the elements of the electric drive train include an electrical energy storage battery.

[0067] The present invention also relates to a heat regulation system, comprising:

[0068] - a heat transfer liquid circuit, configured to circulate a heat transfer liquid,

[0069] - A refrigerant fluid circuit having:

[0070] --The main loop, in the direction of flow of the refrigerant fluid, includes:

[0071] ---a compressor, configured to be driven by an electric motor, the compressor configured to transform the refrigerant fluid from an intake pressure to a delivery pressure,

[0072] ---a first heat exchanger, configured to provide thermal power to the heat transfer fluid,

[0073] ---First expansion valve,

[0074] ---a second heat exchanger, arranged jointly on the refrigerant fluid circuit and the heat transfer liquid circuit, so as to receive thermal power from the heat transfer liquid,

[0075] a first bypass branch allowing the refrigerant fluid at the outlet of the compressor to reach the second exchanger by bypassing the first exchanger and the first expansion valve, the first bypass branch comprising the second expansion valve,

[0076] - An electronic control unit configured to implement the above-mentioned control method.

[0077] According to an embodiment of the heat conditioning system, the refrigerant fluid circuit comprises a second bypass branch arranged in parallel with the first expansion valve and the second heat exchanger, the second bypass branch comprising a fourth expansion valve and a fourth heat exchanger.

[0078] For example, the fourth heat exchanger is configured to exchange heat with the air flow inside the vehicle.

[0079] According to one aspect of the heat conditioning system, the main loop of the refrigerant fluid comprises a refrigerant fluid accumulation device arranged downstream of the first exchanger and upstream of the first expansion valve.

[0080] In one embodiment, the main loop of the refrigerant fluid comprises a refrigerant fluid accumulation device arranged downstream of the first exchanger and upstream of the first expansion valve. In one embodiment, the main loop of the refrigerant fluid comprises the first exchanger and the third exchanger, and the refrigerant fluid accumulation device is arranged downstream of the third exchanger and upstream of the first expansion valve.

[0081] According to one embodiment of the thermal regulation system, the main loop of the refrigerant fluid comprises an internal exchanger configured to enable heat exchange between a high-pressure refrigerant fluid downstream of the third heat exchanger and upstream of the first expansion valve and a low-pressure refrigerant fluid downstream of the second exchanger and upstream of the compressor.

[0082] According to one aspect of the heat regulation system, it includes a first bypass branch, which fluidly connects a first connection point arranged on the main loop downstream of the compressor and upstream of the first exchanger to a second connection point arranged on the main loop downstream of the first expansion valve and upstream of the second exchanger, and the first bypass branch has a second expansion device.

[0083] According to one embodiment, the heat regulation system includes a second bypass branch, which fluidly connects a third connection point arranged on the main loop downstream of the third exchanger and upstream of the first expansion valve to a fourth connection point arranged on the main loop downstream of the second exchanger and upstream of the compressor, and the second bypass branch has a fourth expansion device arranged upstream of the fourth heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Further features, details and advantages will become apparent from reading the following detailed description and from studying the accompanying drawings, in which:

[0085] Figure 1 is a schematic diagram of a heat conditioning system according to a first embodiment, in which a control method according to the invention is implemented,

[0086] Figure 2 is a schematic diagram of a heat regulation system according to a second embodiment, in which a control method according to the present invention is implemented,

[0087] Figure 3 yes Figure 2 Schematic diagram of a variation of the heat regulation system in FIG.

[0088] Figure 4 yes Figure 2 A schematic diagram of another variant of the heat regulation system in FIG.

[0089] Figure 5 is a thermodynamic diagram schematically showing the state of the refrigerant fluid when the control method is implemented,

[0090] Figure 6 is a curve illustrating the operation of the control method,

[0091] Figure 7 is a block diagram illustrating the various steps of the method according to the present invention. DETAILED DESCRIPTION

[0092] In order to make the drawings easier to read, the various elements are not necessarily shown to scale. In these drawings, the same elements have the same reference numerals. Certain elements or parameters can be indexed, that is to say designated as, for example, the first element or the second element, or the first parameter and the second parameter, etc. The index is intended to distinguish between similar but not identical elements or parameters. The index does not mean that one element or parameter takes precedence over another, and the names can be interchangeable.

[0093] In the following description, the expression "a first element is upstream of a second element" means that the first element is located before the second element with respect to the direction of circulation or travel of the fluid. Similarly, the expression "a first element is downstream of the second element" means that the first element is located after the second element with respect to the direction of circulation or travel of the fluid in question. In the case of a refrigerant fluid circuit, the expression "a first element is upstream of the second element" means that the refrigerant fluid passes successively through the first element and then through the second element without passing through a compression device. In other words, the refrigerant fluid leaves the compression device, possibly passing through one or more elements, then passing through the first element, then passing through the second element, and then returning to the compression device, in some cases having passed through further elements.

[0094] The expression "a second element is located between a first element and a third element" means that the shortest path from the first element to the third element passes through the second element. When a subsystem is specified to have a given element, this does not exclude the presence of other elements in the subsystem.

[0095] In the described thermal conditioning system 100, the electronic control unit 50 receives information from various sensors (not shown) which in particular measure physical properties of the refrigerant fluid at various points of the circuit. The electronic control unit also receives set points issued by the vehicle occupants, such as the desired temperature of the vehicle interior. The electronic control unit implements control laws for operating the various actuators in order to control the thermal conditioning system 100 so as to achieve the received set points. The electronic control unit 50 in particular implements the method according to the invention.

[0096] The compression device 7 may be an electric compressor, that is to say a compressor whose moving parts are driven by an electric motor 6. The compression device 7 has a suction side for a low-pressure refrigerant fluid, also called the inlet 7a of the compression device, and a delivery side for a high-pressure refrigerant fluid, also called the outlet 7b of the compression device 7. The internal moving parts of the compressor 7 bring the refrigerant fluid from the low pressure or intake temperature Pr_s at the inlet side 7a to the high pressure or delivery pressure Pr_d at the outlet side 7b. After expansion in one or more expansion devices, the refrigerant fluid returns to the inlet 7a of the compressor 7 and a new thermodynamic cycle begins again.

[0097] The refrigerant fluid circuit 10 forms a closed circuit in which the refrigerant fluid can circulate. When the refrigerant fluid circuit 10 is in a nominal operating state, i.e., an operating state without defects or leaks, the refrigerant fluid circuit 10 is sealed. Each connection point of the circuit 10 allows the refrigerant fluid to enter one or the other of the circuit parts that meet at the connection point. By adjusting the opening or closing of the stop valve, check valve or expansion device of each branch, the refrigerant fluid is distributed between the circuit parts that meet at the connection point. In other words, each connection point is a device for redirecting the refrigerant fluid that arrives at the connection point. Therefore, the stop valve and the check valve make it possible to selectively guide the refrigerant fluid to various branches of the refrigerant circuit so as to provide different operating modes, which will be described later.

[0098] In this case, the refrigerant fluid used in the refrigerant fluid circuit 1 is a chemical fluid such as R1234yf. Other refrigerant fluids such as R134a, R290 or R744 may also be used.

[0099] The internal air flow Fi is understood to be the air flow inside the motor vehicle. This internal air flow can circulate in an HVAC (heating, ventilation and / or air conditioning) device. This device is not shown in the various figures. If necessary, the engine fan (not shown) can be started to increase the flow of the internal air flow Fi.

[0100] Figure 1 A thermal regulation system 100 is shown, comprising:

[0101] - a heat transfer liquid circuit 20, configured to circulate a heat transfer liquid,

[0102] - A refrigerant fluid circuit 10 having:

[0103] --Main loop A, in the direction of refrigerant fluid flow, includes:

[0104] --- a compressor 7, configured to be driven by an electric motor 6, the compressor 7 being configured to bring the refrigerant fluid from an intake pressure Pr_s to a delivery pressure Pr_d,

[0105] --- A first heat exchanger 1, configured to provide a thermal power Pw1 to the heat transfer fluid F1,

[0106] ---First expansion valve 31,

[0107] --- a second heat exchanger 2, arranged jointly on the refrigerant fluid circuit 10 and the heat transfer liquid circuit 20, so as to receive a thermal power Pw2 from the heat transfer liquid,

[0108] a first bypass branch B, allowing the refrigerant fluid at the outlet of the compressor 7 to reach the second exchanger 2 by bypassing the first exchanger 1 and the first expansion valve 31, the first bypass branch B including the second expansion valve 32,

[0109] An electronic control unit 50 configured to implement a control method that will be described in detail below.

[0110] The first heat exchanger 1 is configured to perform heat exchange with a heat transfer fluid F1. The first heat exchanger 1 can be used as a condenser. The condensation heat of the refrigerant fluid is transferred to the heat transfer fluid F1. The thermal power Pw1 is thus provided to the heat transfer fluid F1.

[0111] The second heat exchanger 2 is a dual fluid exchanger. In other words, the second heat exchanger 2 includes a first compartment through which the refrigerant fluid travels and a second compartment through which the heat transfer liquid travels. The two compartments are sealed and can perform heat exchange. The dual fluid exchanger includes a refrigerant fluid inlet and outlet, and a heat transfer liquid inlet and outlet. In the second exchanger 2, the refrigerant fluid can therefore receive a thermal power Pw2 from the heat transfer liquid. A heating element 22, such as an electric heating element, can be arranged on the heat transfer liquid circuit 20 to heat the heat transfer liquid under certain operating conditions. Therefore, the thermal power Pw2 is transferred from the heat transfer liquid to the refrigerant fluid in the second exchanger 2. The heating element 22 is optional.

[0112] Each expansion valve of the heat regulating system 100 is a device for expanding a refrigerant fluid. Each expansion valve is configured to change the cross-section of the refrigerant fluid passage. Each expansion valve includes a refrigerant fluid inlet and a refrigerant fluid outlet. The outlet and the inlet are fluidly connected by a pipeline. The movable baffle makes it possible to control the passage cross-section of the pipeline, that is, to provide the passage surface area of ​​the refrigerant fluid. The expansion valve is, for example, an electronic expansion valve, that is, the movable baffle is actuated by an electric motor commanded by an electronic control module. The position of the movable baffle can be closed-loop controlled, that is, the position of the movable baffle is measured and adjusted in real time to obtain a position set point. The refrigerant fluid passage cross-section can be continuously adjusted between a closed position and a maximum open position. The electronic control module of each expansion valve can be integrated in the corresponding expansion valve. According to a variant, the electronic control unit 50 can also command and control each expansion valve.

[0113] The first expansion valve 31 is configured to change the refrigerant fluid passage cross section in the circuit portion located downstream of the first exchanger 1 and upstream of the second connection point 12. The second expansion valve 32 is configured to change the refrigerant fluid passage cross section in the first bypass branch B.

[0114] According to one exemplary embodiment, thermal conditioning system 100 is a thermal conditioning system for a motor vehicle.

[0115] exist Figure 1 In the embodiment of FIG. 4 , the heat transfer fluid F1 is an air flow Fi in the interior of a motor vehicle. The first heat exchanger 1 is arranged in a heating, ventilation and / or air conditioning device.

[0116] In this case, the second heat exchanger 2 is thermally coupled to an element 25 of the electric drive train of the vehicle. The thermal coupling is achieved via a heat transfer liquid in the heat transfer liquid circuit 20. To this end, the heat transfer liquid circulating in the heat transfer liquid circuit 20 exchanges heat with the element 25 of the drive train of the vehicle.

[0117] Thus, the second heat exchanger 2 makes it possible to absorb heat from an element 25 of the vehicle's powertrain. The heat given off by the operation of the element 25 is transferred to the heat transfer fluid in the circuit 20. Depending on the operating conditions, the temperature of the element 25 can be kept within an acceptable range, or the absorbed heat can be transferred to another component in order to heat it.

[0118] The element 25 of the electric drive train comprises, for example, an electric traction motor of the vehicle. In a variant or in addition, the element 25 of the electric drive train comprises an electric energy storage battery. In another variant or in addition, the element 25 of the electric drive train comprises an electronic module for operating the electric traction motor of the vehicle.

[0119] The first bypass branch B fluidly connects a first connection point 11 arranged on the main loop A, downstream of the compressor 7 and upstream of the first exchanger 1, to a second connection point 12 arranged on the main loop A, downstream of the first expansion valve 31 and upstream of the second exchanger 2. Therefore, it should be understood that the first bypass branch B establishes fluid communication between the first connection point 11 and the second connection point 12. The first bypass branch B has a second expansion device 32.

[0120] The main loop A of the refrigerant fluid comprises a refrigerant fluid accumulation device 8 arranged downstream of the first exchanger 1 and upstream of the first expansion valve 31. The refrigerant fluid accumulation device 8 is a receiver-drier.

[0121] The present invention provides a method for controlling a heat regulation system 100, the heat regulation system 100 comprising:

[0122] - a heat transfer liquid circuit 20, configured to circulate a heat transfer liquid,

[0123] - A refrigerant fluid circuit 10 having:

[0124] --Main loop A, in the direction of refrigerant fluid flow, includes:

[0125] --- a compressor 7, configured to be driven by an electric motor 6, the compressor 7 being configured to bring the refrigerant fluid from an intake pressure Pr_s to a delivery pressure Pr_d,

[0126] --- A first heat exchanger 1, configured to provide a thermal power Pw1 to the heat transfer fluid F1,

[0127] ---First expansion valve 31,

[0128] --- A second heat exchanger 2, which is arranged on the refrigerant fluid circuit 10 and the heat transfer liquid circuit 20, so as to be able to exchange heat between the refrigerant fluid and the heat transfer liquid,

[0129] a first bypass branch B, allowing the refrigerant fluid at the outlet of the compressor 7 to reach the second exchanger 2 by bypassing the first exchanger 1 and the first expansion valve 31, the first bypass branch B having a second expansion valve 32,

[0130] The control method comprises the following steps:

[0131] (i) receiving a thermal power set point C_Pw of the thermal power to be provided to at least the heat transfer fluid F1 at the first exchanger 1,

[0132] (ii) determining an electric power setpoint C_Pw_el of the electric power to be supplied to the electric motor 6 of the compressor 7 based on the received thermal power setpoint C_Pw of the thermal power to be supplied and the thermal power Pw2 received by the second exchanger 2,

[0133] (iii) determining a delivery pressure set point C_Pr_d based on the determined electric power set point C_Pw_el and on the maximum delivery pressure Pr_d_max,

[0134] (iv) determining an intake pressure set point C_Pr_s based on the determined electric power set point C_Pw_el and based on the determined delivery pressure set point C_Pr_d,

[0135] (v) controlling the speed N of the electric motor 6 of the compressor 7 so that the electric power Pw_el supplied to the compressor 7 is equal to the determined set point C_Pw_el,

[0136] (vi) controlling the passage cross section of the second expansion valve 32 so that the intake pressure Ps of the compressor 7 is equal to the determined intake pressure set point C_Pr_s,

[0137] (vii) The passage cross section of the first expansion valve 31 is controlled so that the refrigerant fluid at the inlet of the compressor 7 is in a superheated vapor state.

[0138] This control structure makes it possible to robustly control the amount of refrigerant fluid circulating in the refrigerant fluid circuit, as well as the distribution of the refrigerant fluid flow between the flow circulating in the main loop and passing through the first exchanger and the flow circulating in the first bypass branch and merging with the main branch flow downstream of the first expansion valve.

[0139] In step (ii), the electric power setpoint C_Pw_el of the electric power to be supplied to the electric motor 6 of the compressor 7 is equal to the received setpoint C_Pw of the thermal power to be supplied minus the thermal power Pw2 received by the second exchanger 2 .

[0140] Specifically: C_Pw_el=C_PW-PW2

[0141] In step (iv), the intake pressure setpoint C_Pr_s is determined based on the electric power setpoint C_Pw_el, on the determined delivery pressure setpoint C_Pr_d and on the maximum permissible rotational speed of the compressor 7 .

[0142] The maximum permissible speed depends on the forward speed of the vehicle. Thus, the maximum permissible speed may be higher when the vehicle is moving than when the vehicle is stationary, because the background noise is higher when the vehicle is moving. The maximum permissible speed may, for example, be mapped as a function of the vehicle speed, that is, the value of the maximum permissible speed is looked up in a table by an input, the input being the vehicle speed.

[0143] The maximum delivery pressure Pr_d_Max may be a constant value, for example 27 bar.

[0144] The maximum delivery pressure Pr_d_Max may correspond to a maximum permissible pressure ensuring the long-term reliability of the compressor 7. The use of a constant value makes it possible to simplify the control method.

[0145] According to a variant, the maximum delivery pressure Pr_d_Max may be a tabulated value, for example based on the vehicle's forward travel speed. Tabulated value is understood to mean that the value of the maximum delivery pressure may be looked up in a table (also called a map), various output values ​​being assigned according to the input values ​​of the table.

[0146] Thus, the maximum delivery pressure Pr_d_Max may depend on the operating conditions. For example, the maximum delivery pressure Pr_d_Max may depend on the forward speed of the vehicle. Thus, when the vehicle is stopped, the maximum pressure provided by the compressor 7 may be limited to limit the noise generated, which may be particularly annoying if the vehicle is moving without generating noise.

[0147] According to one embodiment of the method, the electric power setpoint E_Pw_el of the electric power to be supplied to the electric motor 6 of the compressor 7 is, for example, equal to the received total heating power setpoint. In other words, the efficiency of the compressor 7 is assumed to be ideal.

[0148] According to a variant, the electric power setpoint C_Pw_el of the electric power to be supplied to the electric motor 6 of the compressor 7 may be equal to the received total heating power setpoint divided by the adiabatic efficiency of the compressor 7. In this case, the electric power setpoint is therefore calculated more accurately, since the efficiency is no longer assumed to be perfect. The efficiency can be characterized and, for example, mapped under various operating conditions.

[0149] The passage section of the first expansion valve 31 is controlled, for example, by a proportional-integral controller. Similarly, the passage section of the second expansion valve 32 can be controlled by a proportional-integral controller. This type of controller ensures robust control while still being easy to program and fine-tune.

[0150] According to one embodiment of the method, the control of the passage cross section of the first expansion valve 31 and the control of the passage cross section of the second expansion valve 32 are configured such that:

[0151] - an increase in the channel cross section of the first expansion valve 31 leads to a decrease in the channel cross section of the second expansion valve 32,

[0152] The increase in the passage cross section of the second expansion valve 32 leads to an increase in the passage cross section of the first expansion valve 31 .

[0153] The coupling between the correction of the passage cross section of the first expansion valve 31 and the correction of the passage cross section of the second expansion valve 32 makes it possible to improve control stability. The gain associated with the reduction of the passage cross section of the second expansion valve 32 is, for example, equal to half of the gain associated with the increase of the passage cross section of the first expansion valve 31. Therefore, when the controller opens the first expansion valve 31 by a certain amount, it simultaneously closes the second expansion valve 32 by a value equal to half of the amount.

[0154] According to the example described here, the main loop A of the refrigerant fluid circuit 10 comprises a third expansion valve 33 arranged downstream of the compressor 7 and upstream of the first heat exchanger 1, the method comprises the following steps:

[0155] (viii) The refrigerant fluid passage cross section in the third expansion valve 33 is controlled so that the delivery pressure Pr_d is equal to the determined delivery pressure set point C_Pr_d.

[0156] Therefore, step (viii) comprises the following sub-step: determining the delivery pressure Pr_d.

[0157] Figure 5 The thermodynamic state of the refrigerant fluid during the thermodynamic cycle is shown. The values ​​on the abscissa axis are the enthalpy of the refrigerant fluid. The values ​​on the ordinate axis are the pressure of the refrigerant fluid, using a logarithmic scale. Curve S is the saturation characteristic curve of the refrigerant fluid used. The region illustrated between the saturation curve S and the abscissa axis corresponds to the two-phase region of the refrigerant fluid.

[0158] Point A7a represents the state of the refrigerant fluid at the inlet of the compressor 7. The pressure of the refrigerant fluid at this point is equal to the intake pressure Pr_s. Point A7b represents the state of the refrigerant fluid at the outlet of the compressor 7. The pressure at this point is equal to the delivery pressure Pr_d. Point A1a represents the state of the refrigerant fluid at the inlet 1a of the first exchanger 1. The third expansion valve 33 causes partial expansion of the refrigerant fluid, so that the pressure of the refrigerant fluid in the first exchanger 1 is less than the delivery pressure Pr_d of the compressor 7.

[0159] Ensuring partial expansion of the refrigerant fluid in the third expansion valve 33 forces the compressor 7 to compress the refrigerant fluid to a value higher than the condensation pressure in the first exchanger 1. This increases the thermal power received by the refrigerant fluid when it is compressed. The temperature rise of the thermal conditioning system 100 is thus accelerated. In addition, using a delivery pressure as high as possible makes it possible to reduce the rotation speed of the compressor 7, thereby reducing the level of operating noise.

[0160] The high-pressure refrigerant fluid flow at the outlet of the compressor 7 is divided between a first flow, which circulates in the main circuit A and passes through the first exchanger 1, and a second flow, which circulates in the first bypass branch B, and the division into two flows is performed at the first connection point 11. The refrigerant fluid that circulates in the main circuit A and is partially expanded by the third expansion valve 33 is condensed in the first exchanger 1 by releasing heat to the heat transfer fluid F1. The indicator Q1 indicates the amount of heat transferred, and the point A8 represents the state of the refrigerant fluid at the outlet of the accumulation device 8. The refrigerant fluid leaving the first exchanger 1 is then expanded at the first expansion valve 31. Point A31a represents the state of the refrigerant fluid at the inlet of the first expansion valve 31, and point A31b represents the state at the outlet of the first expansion valve 31, that is, the state after expansion. At this point, the refrigerant fluid is two-phase, mainly in liquid form.

[0161] The flow circulating in the first bypass branch B undergoes expansion at the second expansion valve 32. Point A32b represents the thermodynamic state of the refrigerant fluid at the outlet of the second expansion valve 32. At this point in the cycle, the refrigerant fluid is in a superheated vapor state. This superheated vapor flow circulating in the first bypass branch B is mixed with the two-phase refrigerant fluid flow circulating in the main loop A at the second connection point 12 and reaches the inlet 2a of the second exchanger 2. Point A2a shows the state of the mixing point. The flow of superheated vapor is controlled so that the obtained mixture is completely in gaseous form, that is to say in the form of superheated vapor. This ensures the reliability of the compressor 7, as there is no risk of the compressor 7 receiving liquid refrigerant. Point A2b represents the state of the refrigerant fluid at the outlet of the second exchanger 2. The heat exchange at the second exchanger 2 can be ignored. At Figure 5In FIG. 1 , the head losses caused by the second exchanger 2 have been exaggerated to make the diagram easier to read. The refrigerant fluid leaving the second exchanger 2 reaches the inlet of the compressor 7, represented by point A7a. The thermodynamic cycle is thus completed.

[0162] Figure 6 The relationship between the intake pressure Pr_s at the compressor inlet and the electric power Pw_el supplied to the compressor is shown for a given fixed delivery pressure Pr_d, for example 25 bar. Curve N1 corresponds to a constant rotation speed N of the compressor, in this case equal to 5000 rpm. Curve N2 corresponds to a speed greater than N1, in this case 6000 rpm, and curve N3 corresponds to a constant speed greater than N2, in this case 7000 rpm. At constant speed, the electric power consumed by the compressor is an increasing function of the intake pressure Pr_s. For a given intake pressure, the electric power consumed by the electric motor 6 driving the compressor 7 increases with increasing speed. For the entire speed range of the compressor 7, for the entire allowable intake pressure range and the entire allowable delivery pressure range, such a cluster of curves is determined. The cluster of curves allows the control method to determine the intake pressure, the delivery pressure and the rotation speed, which makes it possible to obtain the set point of the electric pressure consumed by the compressor and thus the set point of the thermal power to be released.

[0163] According to one embodiment, the method comprises the following steps:

[0164] (vii1) determining the superheat Sh of the refrigerant fluid at the inlet of the compressor 7,

[0165] (vii2) The passage cross section of the first expansion valve 31 is controlled so that the superheat Sh of the refrigerant fluid at the inlet of the compressor 7 is equal to the set point value C_Sh.

[0166] The superheat set point C_Sh at the inlet of the compressor 7 is selected to ensure that the refrigerant sucked by the compressor 7 is completely in gaseous form, thereby ensuring the reliability of the compressor 7. Control of the passage cross section of the second expansion valve 32 makes it possible to control the superheated steam flow circulating in the first bypass branch B and therefore control the composition of the mixture indicated by the point A2a.

[0167] The set point value C_Sh of the superheat of the refrigerant fluid at the inlet of the compressor 7 is, for example, 5°C to 15°C.

[0168] By definition, the superheat at the inlet of the compressor 7 is equal to the temperature of the refrigerant fluid at the inlet of the compressor 7 minus the condensation temperature value of the refrigerant fluid, which corresponds to the pressure of the refrigerant fluid at the inlet of the compressor 7, i.e., the intake pressure Pr_s. The temperature of the refrigerant fluid is measured, for example, by a temperature sensor, the sensing element of which is in contact with the refrigerant fluid. Similarly, the pressure of the refrigerant fluid is measured, for example, by a pressure sensor, the sensing element of which is in contact with the refrigerant fluid.

[0169] According to another embodiment, the method comprises the following steps:

[0170] (vii1′) determining the superheat Dsh of the refrigerant fluid at the outlet of the compressor 7,

[0171] (vii2′) The passage cross section of the first expansion valve 31 is controlled so that the superheat of the refrigerant fluid at the outlet of the compressor 7 is equal to the set point value C_Dsh.

[0172] Controlling the superheat set point C_Dsh at the outlet of the compressor 7 is another way to ensure that the refrigerant sucked by the compressor 7 is completely in gaseous form, thereby ensuring the reliability of the compressor 7.

[0173] The set point value C_Dsh of the superheat of the refrigerant fluid at the outlet of the compressor 7 is 15°C to 35°C.

[0174] The superheat degree Dsh at the outlet of the compressor 7 is equal to the measured temperature of the refrigerant fluid at the outlet of the compressor 7 minus the condensation temperature value of the refrigerant fluid, which corresponds to the pressure of the refrigerant fluid at the outlet of the compressor 7, that is, the delivery pressure Pr_d.

[0175] Figure 2 A second embodiment of a heat regulation system 100 is shown, in which the control method is implemented. In this second embodiment, the main loop A of the heat regulation system 100 comprises a third heat exchanger 3 downstream of the first heat exchanger 1 and upstream of the first expansion device 31, which is arranged jointly on the refrigerant fluid circuit 10 and the heat transfer liquid circuit 20 so as to enable heat exchange between the refrigerant fluid and the heat transfer liquid. The third heat exchanger 3 is configured to provide a thermal power Pw3 to the heat transfer liquid.

[0176] In step (i) of the control method, the thermal power set point Pw of the thermal power to be provided is the total thermal power Pw_tot, which is the sum of the thermal power Pw1 to be provided to the heat transfer fluid F1 at the first exchanger 1 and the thermal power Pw3 to be provided to the heat transfer liquid at the third exchanger 3.

[0177] While in the first embodiment the refrigerant fluid provides thermal power to the first heat transfer fluid F1 only at the first exchanger 1, in the second embodiment the refrigerant fluid also provides thermal power to the heat transfer liquid in the circuit 20 at the third exchanger 3. The thermal power set point Pw of the thermal power to be provided corresponds to the total power to be provided, i.e. the thermal power provided by the first exchanger 1 plus the thermal power provided by the third exchanger 3.

[0178] The third heat exchanger 3 is a dual fluid exchanger. It can have a similar structure to the second exchanger 2. Its exchanger is, for example, a plate exchanger.

[0179] In other words, in this second embodiment, the main loop A comprises in series in sequence: the compressor 7, the first connection point 11, the third expansion valve 33, the first exchanger 1, the third exchanger 3, the accumulation device 8, the first expansion valve 31, the second connection point 12, the second exchanger 2 and the circuit portion extending between the outlet 2b of the second exchanger 2 and the inlet 7a of the compressor 7. The condensation of the high-pressure refrigerant fluid occurs partly in the first exchanger 1 and partly in the second exchanger 2. Therefore, the first heat transfer fluid F1 can be heated at the first exchanger 1 and the heat transfer liquid in the circuit 20 can be heated at the third exchanger 3. The total thermal power Pw to be provided is distributed between the thermal power Pw1 provided by the first exchanger 1 to the first heat transfer fluid F1 and the thermal power Pw3 provided by the third exchanger 3 to the heat transfer liquid circulating in the heat transfer liquid circuit 20. The distribution between the thermal power Pw1 and the thermal power Pw3 can be achieved by adjusting control parameters, which will not be explained in detail.

[0180] In this embodiment, the first bypass branch B allows the refrigerant fluid at the outlet of the compressor 7 to reach the second exchanger 2 by bypassing the first exchanger 1, the third exchanger 3 and the first expansion valve 31. Specifically, the first bypass branch B connects a point arranged upstream of the third expansion valve 33 to a point arranged downstream of the first expansion valve 31.

[0181] In this embodiment, the main loop A of the refrigerant fluid comprises a refrigerant fluid accumulation device 8 arranged downstream of the first exchanger 3 and upstream of the first expansion valve 31. In other words, the receiver-drier 8 is arranged between the third exchanger 3 and the first expansion valve 31.

[0182] The third heat exchanger 3 is thermally coupled to an element 25 of the drive train of the vehicle via a heat transfer liquid in a heat transfer liquid circuit 20 .

[0183] The third heat exchanger 3 thus makes it possible to supply thermal power to an element 25 of the drive train of the vehicle, that is to say to heat this element 25. The second exchanger 2 is able to receive thermal power from the element 25 in order to cool it or to collect energy. The heat transfer liquid circuit 20 is not shown in detail and is shown in dashed lines at the third exchanger 3 and the second exchanger 2. In order to make the representation simpler and to avoid that the lines of the various circuits cross each other, the circuit 20 is shown in two separate parts.

[0184] Figure 3 Shows Figure 2 In this variation, the heat transfer fluid F1 is a heat transfer liquid arranged to circulate in a fifth heat exchanger 5 arranged to exchange heat with an air flow Fi inside the vehicle.

[0185] The fifth heat exchanger 5 is arranged on the second heat transfer liquid circuit 21. The vehicle interior is heated indirectly, since the heat of condensation of the refrigerant fluid is first transferred to the heat transfer liquid in the circuit 21, and then the heat of the heat transfer liquid is transferred to the interior air flow Fi at the fifth exchanger 5. A pump (not shown) can circulate the heat transfer liquid in the circuit 21. The other exchangers have the same Figure 2 The heat transfer fluid circuit 21 for heating the vehicle interior and the heat transfer fluid circuit 20 for the element 25 thermally coupled to the drive train are separate, that is to say they are not connected.

[0186] In the second embodiment and its variations, the refrigerant fluid circuit 10 includes a second bypass branch C arranged in parallel with the first expansion valve 31 and the second heat exchanger 2 , the second bypass branch C including the fourth expansion valve 34 and the fourth heat exchanger 4 .

[0187] The second bypass branch C fluidly connects a third connection point 13 arranged on the main loop A downstream of the third exchanger 3 and upstream of the first expansion valve 31 to a fourth connection point 14 arranged on the main loop A downstream of the second exchanger 2 and upstream of the compressor 7. The second bypass branch C has a fourth expansion device 34 arranged upstream of the fourth heat exchanger 4.

[0188] The fourth heat exchanger 4 is configured to exchange heat with the air flow Fi inside the vehicle. The fourth heat exchanger 4 is arranged in a heating, ventilation and / or air conditioning device.

[0189] exist Figure 1 Examples and Figure 2 and Figure 4 In an embodiment in which the first exchanger 1 is arranged in a heating, ventilation and / or air conditioning device, the first exchanger 1 is arranged downstream of the fourth exchanger 4 in the flow direction of the internal air flow Fi. Figure 3In the variant shown, in the heating, ventilation and / or air-conditioning device, a fifth exchanger 5 is arranged downstream of the fourth exchanger 4. The fourth exchanger 4 makes it possible to ensure cooling of the vehicle interior in order to keep the vehicle passengers thermally comfortable by means of a warm environment.

[0190] Figure 4 Shows Figure 2 Another variation of an embodiment of the heat regulation system 100 in FIG. The main loop A of the refrigerant fluid comprises an internal exchanger 9 configured to enable heat exchange between the high-pressure refrigerant fluid downstream of the third heat exchanger 3 and upstream of the first expansion valve 31 and the low-pressure refrigerant fluid downstream of the second exchanger 2 and upstream of the compressor 7.

[0191] The internal heat exchanger 9 has a first heat exchange section 9a arranged downstream of the refrigerant fluid accumulation device 8 and upstream of the first expansion device 31, and a second heat exchange section 9b arranged downstream of the second heat exchanger 2. Heat is exchanged between the refrigerant fluid in the first heat exchange section 9a and the refrigerant fluid in the second heat exchange section 9b. The internal exchanger 9 can improve the performance of the heat conditioning system 100.

[0192] According to a variant not shown, the main circuit A of the refrigerant fluid may have a subcooling exchanger arranged downstream of the accumulation device 8 and upstream of the first expansion valve 31. The subcooling exchanger makes it possible to increase the thermal cooling power when the thermal conditioning system is used in cooling mode.

Claims

1. A control method for controlling a heat regulation system (100), the heat regulation system (100) comprising: A heat transfer liquid circuit (20) is configured to circulate a heat transfer liquid. A refrigerant fluid circuit (10) having: The main loop (A) includes, in the direction of flow of the refrigerant fluid: a compressor (7) configured to be driven by an electric motor (6), said compressor (7) being configured to bring said refrigerant fluid from an intake pressure (Pr_s) to a delivery pressure (Pr_d), A first heat exchanger (1) configured to provide thermal power (Pw1) to a heat transfer fluid (F1), a first expansion valve (31), a second heat exchanger (2), arranged jointly on the refrigerant fluid circuit (10) and the heat transfer liquid circuit (20) so as to receive thermal power (Pw2) from the heat transfer liquid, a first bypass branch (B) allowing the refrigerant fluid at the outlet of the compressor (7) to reach the second exchanger (2) by bypassing the first exchanger (1) and the first expansion valve (31), the first bypass branch (B) having a second expansion valve (32), The control method comprises the following steps: (i) receiving a thermal power set point (C_Pw) for the thermal power to be provided to at least the heat transfer fluid (F1) at said first exchanger (1), (ii) determining an electric power set point (C_Pw_el) for the electric power to be supplied to the electric motor (6) of the compressor (7) based on the received thermal power set point (C_Pw) for the thermal power to be supplied and based on the thermal power (Pw2) received by the second exchanger (2), (iii) determining a delivery pressure set point (C_Pr_d) based on the determined electric power set point (C_Pw_el) and on the maximum delivery pressure (Pr_d_max), (iv) determining an intake pressure set point (C_Pr_s) based on the determined electric power set point (C_Pw_el) and based on the determined delivery pressure set point (C_Pr_d), (v) controlling the speed (N) of the electric motor (6) of the compressor (7) so that the electric power supplied to the compressor (7) is equal to the determined set point (C_Pw_el), (vi) controlling the passage cross section of the second expansion valve (32) so that the intake pressure (Ps) of the compressor (7) is equal to the determined intake pressure set point (C_Pr_s), (vii) controlling the passage cross section of the first expansion valve (31) so that the refrigerant fluid at the inlet of the compressor (7) is in the superheated vapor state.

2. The method according to claim 1, wherein: The main loop (A) of the refrigerant fluid circuit (10) comprises a third expansion valve (33), the third expansion valve (33) being arranged downstream of the compressor (7) and upstream of the first heat exchanger (1), the method comprising the following steps: (viii) controlling the refrigerant fluid passage cross section in the third expansion valve (33) so that the delivery pressure (Pr_d) is equal to the delivery pressure set point (C_Pr_d).

3. The method according to claim 1 or 2, comprising the following steps: (vii1) determining the superheat (Sh) of the refrigerant fluid at the inlet of the compressor (7), (vii2) controlling the passage cross section of the first expansion valve (31) so that the superheat (Sh) of the refrigerant fluid at the inlet of the compressor (7) is equal to the set point value (C_Sh).

4. The method according to claim 1 or 2, comprising the following steps: (vii1') determining the superheat (Dsh) of the refrigerant fluid at the outlet of the compressor (7), and (vii2') controlling the channel cross-section of the first expansion valve (31) so that the superheat of the refrigerant fluid at the outlet of the compressor (7) is equal to the set point value (C_Dsh).

5. A method according to any one of the preceding claims, wherein: The main loop (A) of the heat regulation system (100) comprises a third heat exchanger (3) downstream of the first heat exchanger (1) and upstream of the first expansion device (31), the third heat exchanger (3) being arranged jointly on the refrigerant fluid circuit (10) and the heat transfer liquid circuit (20) so as to be able to exchange heat between the refrigerant fluid and the heat transfer liquid, the third heat exchanger (3) being configured to provide thermal power (Pw3) to the heat transfer liquid, wherein, in step (i), The thermal power set point (Pw) of the thermal power to be provided is the total thermal power (Pw_tot), which is the sum of the thermal power (Pw1) to be provided to the heat transfer fluid (F1) at the first exchanger (1) and the thermal power (Pw3) to be provided to the heat transfer liquid at the third exchanger (3).

6. The method according to any one of claims 1 to 5, wherein: The heat transfer fluid (F1) is the interior air flow (Fi) inside the motor vehicle.

7. The method according to any one of claims 1 to 5, wherein: The heat transfer fluid (F1) is a heat transfer liquid configured to flow in a fifth heat exchanger (5), and the fifth heat exchanger (5) is configured to exchange heat with an air flow (Fi) inside the vehicle.

8. A method according to any one of the preceding claims, wherein: The second heat exchanger (2) is thermally coupled to an element (25) of a drive train of a vehicle via a heat transfer liquid in the heat transfer liquid circuit (20).

9. A method according to any one of the preceding claims in combination with claim 5, wherein: The third heat exchanger (3) is thermally coupled to an element (25) of a drive train of a vehicle via a heat transfer liquid in the heat transfer liquid circuit (20).

10. A heat regulation system (100), comprising: A heat transfer liquid circuit (20) is configured to circulate a heat transfer liquid. A refrigerant fluid circuit (10) having: The main loop (A) includes, in the direction of flow of the refrigerant fluid: a compressor (7) configured to be driven by an electric motor (6), said compressor (7) being configured to bring said refrigerant fluid from an intake pressure (Ps) to a delivery pressure (Pd), A first heat exchanger (1) configured to provide thermal power (Pw1) to a heat transfer fluid (F1), a first expansion valve (31), a second heat exchanger (2), arranged jointly on the refrigerant fluid circuit (10) and the heat transfer liquid circuit (20) so as to receive thermal power (Pw2) from the heat transfer liquid, a first bypass branch (B) allowing the refrigerant fluid at the outlet of the compressor (7) to reach the second exchanger (2) by bypassing the first exchanger (1) and the first expansion valve (31), the first bypass branch (B) comprising a second expansion valve (32), An electronic control unit (50) is configured to implement the control method as claimed in any one of the preceding claims.

11. The heat conditioning system (100) according to claim 10, wherein: The refrigerant fluid circuit (10) comprises a second bypass branch (C) arranged in parallel with the first expansion valve (31) and the second heat exchanger (2), the second bypass branch (C) comprising a fourth expansion valve (34) and a fourth heat exchanger (4), wherein the fourth heat exchanger (4) is configured to perform heat exchange with an air flow (Fi) inside the vehicle.

12. The heat conditioning system (100) according to claim 10 or 11, wherein: The main refrigerant fluid loop (A) comprises a refrigerant fluid accumulation device (8) arranged downstream of the first exchanger (1) and upstream of the first expansion valve (31).

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