Climate chamber with heat control for motion simulator and heat control method and installation kit

Description

Technical field

[0001] The present invention relates generally to the field of metrology. It relates to a thermally regulated climatic chamber that can be embedded in a motion simulator as well as a thermal regulation method. It may also relate to an installation kit for a thermally regulated climatic chamber for a motion simulator. It has applications for the thermal characterization of equipment dynamically tested in a motion simulator. Technological background

[0002] Motion simulators are rotating machines designed to test equipment that can be sensors such as isolated inertial components or complete inertial systems, typically gyrometers, accelerometers, inertial measurement units, etc. The majority of these tests require temperature characterization in order to evaluate and compensate for the thermal drift of the equipment, both statically, i.e. in temperature steps, and dynamically, i.e. in temperature ramps. In both cases, temperature setpoint monitoring and temperature stability are important performance indicators. It is also preferable that the tests can be carried out over a very wide temperature range, for example between -55°C and +125°C.

[0003] For this purpose, climatic chambers are traditionally implemented in which the equipment is installed, the climatic chamber being installed in a typically multi-axis movement simulator.

[0004] Known refrigeration systems used in motion simulators are typically mechanical, based on the reverse Rankine cycle, or open-circuit systems using CO2 or N2 expansion in the liquid phase. These systems allow a very wide range of temperatures to be achieved.

[0005] In the case of open circuit systems, the gas is lost after expansion in the climatic chamber and it is necessary to provide means of controlling the oxygen level in the ambient air in the case of N2 or the level of gas used in the case of CO2.

[0006] Mechanical systems, on the other hand, operate in a closed circuit, without needing to control the oxygen level in the air, and they use an evaporator in the climatic chamber, thus making it heavier and penalizing the dynamics as well as the bandwidth of the motion simulators.

[0007] Previous systems use solenoid valves, generally of the on / off type, to control the flow of liquid to the evaporator and therefore the cooling power in the climatic chamber. Controlling the solenoid valve can compromise position and speed stability performance through at least two phenomena that can be likened to shocks on the mechanical structure of the simulator: the movements of the solenoid valve armature, and water hammer in the hydraulic circuit of the liquid phase.

[0008] Furthermore, the operation is not continuous, as it consists of a series of successive cycles of injection / evaporation of refrigerant into the evaporator in the case of mechanical refrigeration, or even of liquid N2 or CO2 directly into the volume of the climatic chamber in the case of an open circuit. These cycles also generate a variation in the cooling power during the tests. This is called pulse width modulation or PWM control, with the pulse width being the relative opening time of the solenoid valve, called the duty cycle. An operating periodicity of several seconds is not negligible given the thermal inertia of the various components of the climatic chamber, and this results in inevitable temperature oscillations. In addition, this periodicity also penalizes the bandwidth to the extent that it induces a pure delay in the control of the system.

[0009] Therefore, the use of static refrigeration systems using thermoelectric modules has been proposed to avoid the problems mentioned above. Indeed, thermoelectric modules, also known as Peltier modules, have many advantages: Precise regulation thanks to their high linearity and continuous operation: the power is constantly proportional to the current around an operating point. Low time constant compared to mechanical systems, which allows to considerably increase the bandwidth of the system and its rejection of disturbances and thus the temperature stability. The time constant is then negligible compared to the thermal inertia of the different components of the climatic chamber. Entirely static system: without mechanical disturbances, unlike systems with fluids and embedded solenoid valves. Use of thermoelectric modules in the production of heat or cold thanks to their reversibility.

[0010] A thermoelectric cooling module has already been implemented in a motion simulator, but this was done by installing the thermoelectric module directly on the equipment to be tested for temperature characterization. Cooling is therefore carried out by direct conduction on the equipment under test, as is standard practice in electronics for thermoelectric modules. Therefore, there was no thermal regulation by a climatic chamber.

[0011] However, the equipment to be tested is generally complex devices which may contain materials on the surface with very different or low thermal conductivities and / or have irregular shapes which limit or prevent the direct attachment of one or more thermoelectric modules to the equipment.

[0012] It is therefore preferable to use a climatic chamber in which the equipment to be tested can be installed, with temperature regulation being ensured inside the climatic chamber.

[0013] Thermoelectric modules, however, have certain limitations. In particular, at room temperature, single-stage thermoelectric modules do not produce more than 70-80°C of temperature difference, ΔT, between their cold and hot faces with powers of several hundred watts under ideal conditions. Multi-stage versions (2, 3 or even 4 or 5 modules stacked, i.e. thermally in series) accept a larger temperature difference, ΔT, (up to 130°C) but at the cost of very low powers, of the order of twenty watts at ΔT = 0, which makes them suitable for very specific applications such as the cooling of CCD / CMOS sensors in order to reduce thermal noise. In fact, the power and ΔT of thermoelectric modules depend on the temperature of the hot face.

[0014] In conventional solutions, a forced convection heat sink is often used on the hot side, but this cannot drop below ambient temperature, which limits the range of low temperatures achievable on the cold side.

[0015] In this area, solutions have been proposed in the following documents: US 3 252 504 A, DE 10 2010 026601 A1 and WO 2008 / 010675 A1. Statement of the invention

[0016] It is proposed, within the framework of the invention which relates to a climatic chamber with thermoelectric assemblies for in particular a movement simulator, the implementation of a secondary thermal regulation circuit which is applied to the external face(s) of the chamber of the thermoelectric assemblies, and which comprises a means for cooling or heating a heat transfer fluid of said secondary thermal regulation circuit and for exchanging heat energy (or "calories" in the rest of the text) with said external face(s) of the thermoelectric assemblies. In this system, the thermoelectric assemblies of the climatic chamber form a primary thermal regulation device. In addition, the interior of the climatic chamber, interior which is subjected to the internal face(s) of the thermoelectric assemblies, is preferably forced convection.

[0017] It is thus possible to obtain a very wide range of temperatures while implementing a thermal regulation device which is static on the climatic chamber. The secondary thermal regulation circuit implements one or more thermoelectric regulation assemblies each comprising one or more thermoelectric modules.

[0018] More specifically, according to the invention, a thermally regulated climatic chamber is proposed for testing at least one piece of equipment, the climatic chamber comprising a wall defining an internal space containing a gas and capable of receiving and containing said at least one piece of equipment to be tested, the internal space being thermally insulated from the environment outside the climatic chamber, in which at least one thermoelectric assembly is arranged through the wall of the climatic chamber, each thermoelectric assembly comprising two faces, an internal face arranged inside the climatic chamber and an external face outside the climatic chamber, and in which one of the two faces, called the cold face, is intended to absorb heat energy and the other, called the hot face, is intended to reject heat energy as a function of the electric current passing through said at least one thermoelectric assembly,wherein a heat exchange end for an external face of a thermoelectric assembly of a secondary thermal regulation circuit is arranged in thermal contact with each external face of the thermoelectric assembly in order to exchange heat energy between said at least one thermoelectric assembly and said secondary thermal regulation circuit, the secondary thermal regulation circuit being external to the climatic chamber and comprising a heat transfer fluid circuit, a cold source, a hot source, a mixing device, a circulation pump and sensors, and wherein a system for regulating the temperature of the chamber is configured to control the electric current of said at least one thermoelectric assembly and to control at least the mixing device and the circulation pump of the secondary thermal regulation circuit as a function of an enclosure temperature setpoint and sensor measurements.,

[0019] It is understood that the principle of implementing at least one thermoelectric assembly arranged across, i.e. passing through, the wall of the climatic chamber must be understood in a functional sense which is to allow thermal exchanges between the interior and the exterior of the climatic chamber. For example, the internal wall of the climatic chamber may be metallic and the thermoelectric assembly(s) are arranged against the external face of the internal metallic wall by passing through a layer of thermal insulation also arranged on the external face of this internal metallic wall.

[0020] Other non-limiting and advantageous characteristics of the climatic chamber according to the invention, taken individually or in all technically possible combinations, are the following: a thermoelectric assembly comprises one or more thermoelectric modules also called Peltier, the secondary thermal regulation circuit therefore comprises a heat exchange end for the external face of the thermoelectric assembly, a gas mixing device is arranged inside the climatic chamber in order to allow mixing of the gas internal to the chamber and on the internal face(s) of said at least one thermoelectric assembly, each internal face of the thermoelectric assembly comprises a finned radiator, the heat transfer fluid remains in the liquid phase in the secondary thermal regulation circuit, the heat transfer fluid has two phases, one gaseous and one liquid, in the secondary thermal regulation circuit, preferably, the external face is a hot face and the internal face is a cold face, heat energy being extracted from the interior of the climatic chamber,the outer face is a cold face and the inner face is a hot face, heat energy being sent to the interior of the climatic chamber, the gas mixing device comprises one or more fans, the temperature regulation system of the chamber further controls the gas mixing device in order to regulate the intensity of the gas mixing in the chamber, the internal space is thermally insulated from the environment outside the chamber, including the motion simulator, the chamber being fixed to the motion simulator by thermally insulating fasteners so as not to create a thermal bridge between the motion simulator and the interior of the climatic chamber, the climatic chamber is fixed on a mobile support of a motion simulator and the mobile support can be driven in movement by means of joints of said motion simulator,in the case where the climatic chamber is fixed on the mobile support of the movement simulator then, in the secondary thermal regulation circuit, the heat exchange end for the external face of the thermoelectric assembly is arranged against the thermoelectric assembly and is therefore movable following the thermoelectric assembly, the remainder of the secondary thermal regulation circuit being arranged outside the movable parts of the movement simulator and being connected to the heat exchange end by movable fluid joints passing through the joints of the movement simulator, the climatic chamber is fixed and is immobile, a movement simulator being installed in the climatic chamber and the equipment is installed on a mobile support of the movement simulator and the equipment can be driven in movement by said movement simulator,the temperature of the heat source is adjustable and the enclosure temperature control system further controls the temperature of the heat source, the enclosure temperature control system is configured to control the temperature of the external face of the thermoelectric assembly according to the enclosure temperature setpoint and so that the polarity of the current flowing in said at least one thermoelectric assembly is constant, the internal face of the thermoelectric assembly being a cold face absorbing heat energy from the interior of the climatic enclosure, one of the temperature sensors is a thermoelectric assembly external face temperature sensor, each thermoelectric assembly comprises a thermoelectric assembly external face temperature sensor,each thermoelectric assembly is in contact with a heat exchange end for the external face of the thermoelectric assembly of the secondary thermal regulation circuit, the heat exchange end for the external face of the thermoelectric assembly of the secondary thermal regulation circuit comprises a fluid outlet on the downstream side and a temperature sensor is arranged on the fluid outlet of the heat exchange end of the secondary thermal regulation circuit, the heat exchange end for the external face of the thermoelectric assembly of the secondary thermal regulation circuit comprises a fluid outlet on the downstream side and the external face temperature sensor of the thermoelectric assembly is arranged on the fluid outlet of the heat exchange end of the secondary thermal regulation circuit, the external face temperature sensor is arranged against the external face of said at least one thermoelectric assembly,the enclosure temperature control system is configured to provide a continuous flow rate of the heat transfer fluid into the heat exchange end of the secondary thermal control circuit, the continuous flow rate of the heat transfer fluid into the heat exchange end is a constant flow rate, the continuous flow rate of the heat transfer fluid into the heat exchange end is a smoothly variable flow rate, the flow rate changes being gradual, the enclosure temperature control system is configured to control the flow rate of the heat transfer fluid while avoiding high-temperature cavitation of the heat transfer fluid that would be due to too high a speed of the heat transfer fluid, the enclosure temperature control system is configured to linearize the opening / flow rate ratio of the three-way valve by means of piecewise interpolation in a tabulation ("Look-up table"),the climatic chamber comprises at least one thermoelectric assembly across the climatic chamber a thermoelectric assembly comprises a thermoelectric module, a thermoelectric assembly comprises several thermoelectric modules, in a thermoelectric assembly comprising several thermoelectric modules, the thermoelectric modules are electrically connected in series or in parallel or in a series-parallel arrangement, the chamber comprises at least two thermoelectric assemblies across the climatic chamber and the thermoelectric assemblies are electrically connected in parallel, a thermoelectric assembly comprises twenty thermoelectric modules electrically connected in series, the chamber comprises two parallel assemblies of five modules in series each, the temperature control system of the chamber comprises at least two control loops,said at least two control loops being a main control loop controlling the electric current of said at least one thermoelectric assembly and at least one secondary control loop controlling the secondary thermal control circuit, the secondary control loop controlling the secondary thermal control circuit comprises a hot and cold sharing control loop and a flow control loop, the movement simulator comprises movable fluid joints and movable electrical connections, in the case of joints rotating around an axis, the movable fluid joints and the movable electrical connections are rotating, in the case of joints in translation, the movable fluid joints are flexible pipes and the movable electrical connections are flexible electrical cables.

[0021] The invention also relates to a method for thermal regulation of a climatic chamber intended to test at least one piece of equipment, in which a climatic chamber with thermoelectric assembly(s) according to the invention is implemented, wherein the climatic chamber is fixed on a mobile support of a movement simulator and the mobile support can be driven in movement by means of articulations of said movement simulator, and in which a secondary thermal regulation circuit is further implemented comprising a heat exchange end for the external face of the thermoelectric assembly, the heat exchange end is placed against the external face(s) of the thermoelectric assembly(s),the remainder of the secondary thermal regulation circuit being arranged outside the moving parts of the motion simulator and being connected to the heat exchange end by moving fluid joints passing through the joints of the motion simulator.,

[0022] The process can be implemented according to all the procedural methods described or resulting from the functions of the material means implemented.

[0023] In particular, it is also possible to implement a system for regulating the temperature of the enclosure which controls the electric current of said at least one thermoelectric assembly and which controls at least the mixing device and the circulation pump of the secondary thermal regulation circuit as a function of an enclosure temperature setpoint and sensor measurements.

[0024] The invention finally relates to a kit for installing a climatic chamber in a movement simulator.

[0025] More specifically, it is a kit for installing a thermally regulated climatic chamber in a movement simulator, the climatic chamber being intended to test at least one piece of equipment, the movement simulator comprising a mobile support driven in movement by means of joints of said movement simulator, which kit comprises: a climatic chamber comprising a wall defining an internal space capable of receiving and containing said at least one piece of equipment to be tested, the internal space capable of comprising a gas and being thermally insulated from the environment external to the climatic chamber, the climatic chamber comprising means for fixing to the mobile support, the chamber further comprising at least one thermoelectric assembly, said at least one thermoelectric assembly being arranged through the wall of the climatic chamber, each thermoelectric assembly comprising two faces, an internal face arranged inside the climatic chamber and an external face outside the climatic chamber, and in which one of the two faces, called the cold face, is intended to absorb heat energy and the other, called the hot face, is intended to reject heat energy as a function of an electric current passing through said at least one thermoelectric assembly,a secondary thermal regulation circuit comprising a heat transfer fluid circuit, means for connection to a cold source, a hot source, a mixing device, a circulation pump and sensors, the heat transfer fluid circuit comprising a heat exchange end for an external face of a thermoelectric assembly intended to come into thermal contact with an external face of a thermoelectric assembly in order to exchange heat energy between said at least one thermoelectric assembly and said secondary thermal regulation circuit,movable fluid joints intended to be installed in joints of the motion simulator to allow the circulation of the heat transfer fluid of the secondary thermal regulation circuit between the heat exchange end which is intended to be installed in the motion simulator against the external face of the thermoelectric assembly and the rest of the secondary thermal regulation circuit which is intended to be installed outside the movable parts of the motion simulator, movable electrical connections intended to be installed in joints of the motion simulator to allow circulation of electric current,an enclosure temperature regulation system intended to control the electric current of said at least one thermoelectric assembly and to control at least the mixing device and the circulation pump of the secondary thermal regulation circuit as a function of an enclosure temperature setpoint and sensor measurements.

[0026] The kit may also include a cold source.

[0027] The enclosure of the kit may further comprise a gas mixing device, said gas mixing device being arranged inside the climatic enclosure in order to allow mixing of the gas internal to the enclosure and on the internal face(s) of said at least one thermoelectric assembly. Brief description of the drawings

[0028] [ Fig. 1 ]schematizes the primary thermal regulation device with thermoelectric assembly of the climatic chamber, the latter being embedded in a movement simulator not shown, a thermal exchange end of a secondary thermal regulation circuit also being shown, [ Fig. 2 ] schematizes the secondary thermal regulation circuit with heat transfer fluid, external to the climatic enclosure, which is intended to exchange heat energy with the hot face of the thermoelectric assembly, and [ Fig. 3 ] schematizes an example of implementation with three control loops. Detailed description of an example of implementation

[0029] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the system and the method of the invention consist of and how they can be implemented.

[0030] In principle, the system of the invention comprises thermal regulation of the internal volume of the climatic enclosure by placing in series / cascade two thermal regulation means: a first, called the primary thermal regulation device and a second, called the secondary thermal regulation circuit.

[0031] The secondary thermal control circuit makes it possible to heat or cool the primary thermal control device, thereby increasing the achievable temperature range in the climatic chamber and the available thermal power.

[0032] The primary thermal regulation device, which is static in its own operation, implements at least one thermoelectric assembly to be able to control the temperature inside the climatic chamber. For this purpose, at least one temperature sensor is arranged in the climatic chamber. The internal face of each assembly is arranged inside the climatic chamber and the external face of each assembly is arranged outside the climatic chamber. Preferably, the internal face is the cold face and the direction of the current passing through the thermoelectric assembly is therefore imposed by the fact that the cold face, the one which “sucks” the calories, is on the internal side of / inside the climatic chamber. In certain operating variants, the internal face can become a hot face or a cold face by reversing the polarity of the current passing through the thermoelectric assemblies.

[0033] In the following description, a mobile climatic enclosure is primarily described because it is installed in a movement simulator and with a primary thermal regulation device whose internal face of the thermoelectric assembly(s) is a cold face.

[0034] The climatic chamber is integral with the motion simulator and is therefore mobile according to the movements of the simulator's joints, typically along rotation and / or translation axes, and depending on how they are controlled. The motion simulator is typically multi-axis. The climatic chamber is filled with a gas. This gas can be air, ambient air, or one or more specific gases other than air. The climatic chamber, which can be opened, in particular for the installation of the equipment, and closed, thermally insulates the interior of the chamber from the external environment. The interior of the climatic chamber can be airtight and gastight and can withstand a depression or an overpressure relative to the exterior, in particular for additional (de)pressure tests on the equipment.A sealed climatic chamber can also allow the introduction of specific gas(es), for example nitrogen or argon, for additional leak tests of the equipment itself, in particular to search for leaks or risks of contamination in the equipment.

[0035] In other implementation methods, the climatic enclosure is not intended to be sealed against overpressure and depression, the gas exchanges between the interior and the exterior at the pressure balance between the interior and the exterior being however reduced and in such a case, the internal gas is typically air and it is at the atmospheric pressure of the environment.

[0036] The cold face of each thermoelectric assembly 10, which is on the Figure 1the internal face 11, comprises a heat exchange surface which is preferably extended by the presence of a radiator 1. The heat exchanges inside the climatic chamber 3 are preferably promoted by a gas mixing device 2 internal to the climatic chamber 3, typically at least one fan blowing or sucking on the exchange surface. Forced convection is therefore implemented in the climatic chamber 3. The radiator 1 is a heat sink of the type used for cooling power components in electronics, for example a finned radiator.

[0037] The hot face of the thermoelectric assembly 10, the one which “rejects” the calories “sucked in” by the cold face, is arranged outside the climatic enclosure and corresponds to the external face 14 of the thermoelectric assembly 10. Each thermoelectric assembly is therefore arranged through the wall of the climatic enclosure and avoiding creating a thermal bridge between the inside and the outside of the climatic enclosure.

[0038] The power supply to the thermoelectric assembly(s) passes through the joints of the motion simulator and uses electrical connections with contacts or collectors, for example rotating or sliding, or contactless transmission of electrical energy by induction or any other suitable means.

[0039] It is advantageous to implement several thermoelectric assemblies and to wire the thermoelectric assemblies in series to increase the supply voltage and thus reduce the circulating electric current, thus limiting the wear of the electrical slip rings arranged in the joints of the motion simulator and the EMC noise that can be generated. It is also possible, by suitable wiring between the thermoelectric assemblies and by using individual addressable control means, one for each thermoelectric assembly, to reduce the total number of electrical connections required, for example two for a power supply bus and one for a data link. The data may include addressed instructions sent to the individual control means and sensor measurements with identifiers, the sensors being arranged in the motion simulator and in particular in the climatic chamber.

[0040] In the preferred implementation method, which is multiple thermoelectric assemblies, individual and independent control of the power of each thermoelectric assembly is implemented, based on the temperature of each individual cold face in the climatic chamber. In such a case, each thermoelectric assembly has its own cold face temperature sensor and its own current regulation.

[0041] In other implementation methods, the control of the power of the thermoelectric assemblies is done globally for all the thermoelectric assemblies, a single internal face temperature sensor or several temperature sensors with averaging of the internal face measurements being implemented and the current for all the thermoelectric assemblies which are therefore regulated globally.

[0042] If a thermoelectric assembly consists of several thermoelectric elements, there is no individual regulation of each element (no sensor + element current regulation), the regulation being carried out on the thermoelectric assembly as a whole, and preferably individually (one regulation per assembly) in the case of the implementation of several thermoelectric assemblies in the system.

[0043] Regarding the external faces of the thermoelectric assemblies in a system with several thermoelectric assemblies, they are in parallel on the secondary thermal regulation circuit.

[0044] Thermal insulation materials may be used to constitute the climatic chamber 3. The climatic chamber 3 may be single-component in a material with low thermal conductivity or be multi-layered with, for example, an external thermal insulation layer and an internal metal wall, possibly connected to the cold face, which may also promote the distribution of heat in the chamber.

[0045] The purpose of the primary thermal regulation device is multiple: Finely and quickly regulate the temperature in the climatic chamber, thanks to the low thermal inertia of said device and the linear and continuous operation of the thermoelectric assembly(s). Expand the temperature range offered by the secondary thermal regulation circuit alone, by working with the ΔT of the thermoelectric assembly(s) in addition. Improve heat exchanges on the cold face and internal heat distribution thanks to forced convection by mixing the gas present in the internal volume of the climatic chamber.

[0046] The secondary thermal regulation circuit 9 exemplified in the Figure 2, uses a heat transfer fluid, and this circuit is intended to introduce or extract heat energy from the external face 14 of the thermoelectric assembly(s) 10. This secondary thermal regulation circuit 9 comprises a heat exchange end 4 for the external face 14 of the thermoelectric assembly 10. The fluid brought by the secondary thermal regulation circuit against the external face 14 of each thermoelectric assembly may be at a low temperature, for example -10°C or even less, -20°C, or high, for example 80°C, or even more, 120°C, or any other temperature in between. It is therefore understood that the heat transfer fluid which is a liquid, is intended to, preferably, remain in the liquid phase over the entire temperature range envisaged. It is possible, for example, to use glycolated water, i.e. water with glycol and / or to provide a pressurized fluid.

[0047] Other fluids can be used: Ethylene glycol, methylene glycol, Coolanol ®< ... The fluids used have the advantage of being able to be heated and cooled at least relative to the ambient temperature. In this way, the operating thermal amplitude of the thermoelectric assemblies can be increased while maintaining a correct thermal / caloric power. In addition, thermoelectric assemblies with several thermoelectric elements thermally connected in series / cascade can be used, which also makes it possible to obtain a greater thermal amplitude but at the expense of thermal power.

[0048] It is understood that in the case where there are several thermoelectric assemblies, the heat exchange end 4 for external face 14 of thermoelectric assembly 10 is divided into several entities, each entity being arranged on an external face 14 of thermoelectric assembly 10 and in this case, these different entities are in parallel so that the different thermoelectric assemblies receive heat transfer fluid at the same temperature.

[0049] Given therefore that the heat exchange end 4 for external face 14 is against the thermoelectric assembly(s) 10 of the climatic chamber 3, it must follow the movements of this climatic chamber.

[0050] Preferably, in the secondary thermal regulation circuit 9, only the heat exchange end 4 is placed on a movable part because against the thermoelectric assembly(s) of the enclosure arranged in the motion simulator, the rest of the secondary thermal regulation circuit 9 being preferably fixed, outside the motion simulator. It is understood that fluid circuits or connections with movable fluid joints connect the two by crossing and / or passing through the joints of the motion simulator. In an alternative embodiment, other components of the secondary thermal regulation circuit 9 are embedded in the motion simulator,

[0051] The secondary thermal regulation circuit 9 comprises the following elements, the terms upstream and downstream being defined with reference to the direction of circulation of the heat transfer fluid imposed by the pump 15 of the circuit: a heat exchange end 4 for external face 14 of thermoelectric assembly 10, possibly in several entities in parallel in the case where there are several thermoelectric assemblies. An active means of ensuring the circulation of a heat transfer fluid, in the example shown it is a circulation pump 15 controlled by the speed of the heat transfer fluid. In a less efficient variant the circulation of the fluid is passive by using the difference in density between the cold fluid and the hot fluid. In another variant a phase change of the fluid is used for the circulation of the fluid. A cold inlet of refrigerated fluid forming a cold source 8, for example coming from a chilled water unit. A heat exchanger heater or hot source 12 to possibly heat the heat transfer fluid that it receives, for example a circulation heater or, preferably, a counter-circulation heater.Any other means of heating the heat transfer fluid can be used, for example by Joule effect with an electrical resistance, by electromagnetic radiation in particular with a suitable heat transfer fluid. A controlled mixing device 13 for adjusting the temperature of the circulating heat transfer fluid, for example a three-way valve. Sensors for measuring and measuring the temperatures of the fluid 5a, 5b, 5c, 5d, the flow rate 6 of the heat transfer fluid, the pressure 7 of the heat transfer fluid. An electronic and / or digital enclosure temperature regulation system for controlling the various effectors, in particular pump, heat exchanger heater, mixer, current of the thermoelectric assembly(s) in intensity and possibly polarity, according to sensor measurements and a temperature setpoint.In practice, this system for regulating the temperature of the enclosure is shared between the primary thermal regulation device and the secondary thermal regulation circuit 9. The secondary thermal regulation circuit is configured with two opposite ends, on one side, the heat exchange end 4 for external face 14 already presented and, on the other side, a cold inlet connected to an iced water group forming the cold source 8. The cold source may or may not be adjustable in temperature. This cold source 8 makes it possible to bring the heat transfer fluid to a low temperature, possibly and preferably negative in degrees Celsius. The heat transfer fluid thus brought to low temperature is in fluidic relation with an upstream side of the three-way valve 13.This three-way valve has an upstream side 16 towards the cold source 8, has a downstream side 17 towards the pump 15, the hot source 12 then the heat exchange end 4 and has a recirculation side 15 connected to the return circuit 18 channeling the heat transfer fluid having passed through the heat exchange end 4. The upstream side 16 and the recirculation side 15 are heat transfer fluid inlets whose respective flow rate ratio can be adjusted. The downstream side 17 is a heat transfer fluid outlet.

[0052] The three-way valve 13 makes it possible to control, by introducing more or less cold, the temperature of the heat transfer fluid which is sent to the heat exchange end 4 thanks to the pump 15 arranged on the downstream side of the three-way valve then through the heat exchanger heater or hot source 12, before reaching the heat exchange end 4. The hot source 12 makes it possible to heat the heat transfer fluid passing through it. The hot source 12 may or may not be temperature adjustable.

[0053] Thus, the three-way valve makes it possible to control the recirculation rate of the fluid having passed through the heat exchange end 4 relative to the fluid coming from the chilled water unit via the cold inlet or cold source 8. Thus, the temperature of the fluid on the downstream side 17 of the three-way valve can be made colder relative to the recirculating heat transfer fluid (that coming out of the heat exchange end 4), by increasing the flow rate coming from the upstream side 16 of the three-way valve 13. The heat exchanger heater or hot source 12, for its part, makes it possible to heat the heat transfer fluid coming from the downstream side 17 of the three-way valve through the pump 15.

[0054] The three-way valve 13 therefore makes it possible to control the quantity of fluid leaving the chilled water unit and is therefore an actuator making it possible to control "the cooling power". In the enclosure temperature regulation system, "The cooling power" provided by the three-way valve is linearized in terms of opening by the use of a "Look-up-table" in order to optimize the regulation.

[0055] The heat exchanger heater allows the heat transfer fluid to be heated. It is therefore an actuator for controlling the "heating power".

[0056] Thus, depending on the recirculation rate within the three-way valve 13 and the heating level provided by the heat exchanger heater 12, the temperature of the heat transfer fluid sent to the heat exchange end 4 of the secondary thermal regulation circuit 9 can be adjusted. It is therefore possible to adjust between a low temperature, that of the chilled water unit of the cold inlet 8 when recirculation through the three-way valve 13 is stopped (upstream side flow = downstream side flow in the three-way valve) and in the absence of heating by the heat exchanger heater 12 and a high temperature corresponding to that of the maximum heating possible by the heat exchanger heater 12 when recirculation is total in the three-way valve (upstream side flow = 0). The intermediate temperatures are obtained by appropriate controls of the recirculation rate in the three-way valve 13 and the heating level of the heat exchanger heater 12.

[0057] It is understood that it is possible to arrange the pump in other locations, for example by reversing the pump 15 and the heat exchanger heater 12 or by placing the pump 15 in the return circuit 18.

[0058] The temperature sensors 5a, 5b, 5c, 5d are placed: 5a, upstream side 16 of the three-way valve for measuring the temperature of the heat transfer fluid coming from the chilled water unit of the cold inlet 8. 5d downstream, i.e. at the outlet of the heat exchange end 4 for external face 14 of thermoelectric assembly 10, on the return circuit 18 of the heat transfer fluid. 5b downstream side of the three-way valve 13. 5c downstream, i.e. at the outlet of the heat exchanger heater 12.

[0059] It is understood that it is possible to reduce the number of temperature sensors in simplified implementation methods.

[0060] By being able to regulate the temperature at the heat exchange end 4 of the secondary thermal regulation circuit 9, the overall efficiency of the system can be optimized by shifting the temperature set point of the secondary thermal regulation circuit as a function of the temperature set point of the climatic chamber. In addition, the ability to modify the temperature set point of the secondary thermal regulation circuit makes it possible to avoid as much as possible the inversion of the polarity of the current flowing in the thermoelectric assemblies, thus extending their service life by avoiding mechanical stress due to the inversion of operation and the functional inversion from hot side to cold side and vice versa.

[0061] Overall, the regulation system implements both the secondary thermal regulation circuit 9 and the primary thermal regulation device with thermoelectric assembly(s) to regulate the temperature in the climatic chamber according to measurements and a temperature setpoint.

[0062] In the example now presented of the enclosure temperature control system, the two actuators (three-way valve and heat exchanger heater) of the secondary thermal control circuit and the associated sensors make it possible to create a hot and cold sharing control / servo loop whose purpose is to regulate the temperature of the fluid in the heat exchange end 4. The specific setpoint of this control loop is based on a criterion for optimizing the operating point of the primary thermal control device as a function of the temperature setpoint for the climatic enclosure.

[0063] Another loop for flow regulation allows the pump 15 to be controlled according to the flow rate. This regulation is necessary to avoid cavitation at high temperature of the fluid, the saturated vapor pressure being able to be very different between the two temperature extremes of the secondary thermal regulation circuit 9. Limiting the flow of heat transfer fluid in the pipes is also useful to reduce the wear of these and to reduce the energy consumption of the pump 15.

[0064] The pressure sensor 7 and the flow meter 6 arranged on the return circuit 18 make it possible to monitor the state of the secondary thermal regulation circuit 9, in particular of the cold part on the cold inlet side, due to possible freezing of the fluid, leaks, and other problems.

[0065] It is understood that it is possible to place these sensors or other sensors in other locations.

[0066] More generally, in the example shown, it is the same heat transfer fluid that is used at the cold inlet and at the heat exchange end for the external face of the thermoelectric assembly. In variants, the fluids between these two ends can be separated by using a heat exchanger between the two. Furthermore, it is understood that other secondary thermal regulation circuit structures can be used by those skilled in the art to provide a heat transfer fluid to the heat exchange end 4 in a range of suitable controllable temperatures. For example, a second three-way valve can be provided connected to a hot source of heat transfer fluid.

[0067] In variants, it is possible to provide an assembly with a three-way valve in divider or mixer mode, an assembly without a three-way valve but with a plate or tube heat exchanger, etc.

[0068] The enclosure temperature regulation system therefore comprises several partially interdependent regulation loops.

[0069] The main control loop acts on the primary thermal control device and concerns the regulation of the internal temperature, noted T i , of the climatic chamber, which is done by applying a regulated current and / or voltage to the thermoelectric assemblies, in practice Peltier components.

[0070] Depending on the implementation methods, the main control loop can act globally on all thermoelectric assemblies or also act individually via a local loop individual to each thermoelectric assembly.

[0071] The enclosure temperature setpoint T ic provided by the user is preferably filtered, generally by a low-pass filter also called a setpoint filter, and the result of this filtering T icfis compared to T i , and the difference T icf - T i feeds a first corrector C 1 which can be of the proportional integral (PI) or proportional integral derivative (PID) type, or of another type, and which will calculate the current and / or voltage command sent to the thermoelectric assemblies.

[0072] A hot and cold sharing control loop is implemented for the control of the secondary thermal control circuit. The temperature, noted T e , of the heat transfer fluid, preferably glycolated water, of the secondary thermal regulation circuit, essentially allowing cooling, is controlled by means of a shared control ("Split / range") which distributes the hot action (hot created for example, by an electrical resistance, see "External res. power" = power of the external resistance of the hot source on the Figure 3) and the cold action (created by the opening and the degree of opening of the three-way valve and possibly its closing). A second corrector C 2 is used for regulation of T e . The instruction T ec of this loop depends on the instruction T ic and is calculated using piecewise interpolation (“Look-up table”) in a tabulation.

[0073] It can be noted that there are dynamic couplings shown diagrammatically by dotted arrows: The internal temperature T i influences T e , as well as T e influences T i indirectly. In the example described these couplings are neglected for the synthesis of the control law but it is understood that in other versions they can be taken into account.

[0074] Finally, still for the control of the secondary thermal regulation circuit, the flow rate of the water in the internal circuit, noted D, is controlled by means of a third flow regulation loop including in this example a PI or PID type corrector noted C 3. The instruction for this loop is noted D c . The actuator of this loop being the voltage and / or current of the pump of the secondary thermal regulation circuit.

[0075] We find on the Fig. 3 the three control loops with their respective correctors C 1 , C 2 and C 3. In relation to the first corrector C 1 , C 2 and C 3, U / I corresponds to the regulated current and / or voltage sent to the thermoelectric assemblies of the climatic chamber.

[0076] In relation to the second proofreader C2, “External res. power” corresponds to the power control of the electric resistance (hot source). Note that it is possible to use a heat exchanger heater other than an electric resistance and that in this case the control will be adapted accordingly. Still for the second corrector C 2, “Valve opening degree” corresponds to the opening / closing control and opening degree of the three-way valve (cold source).

[0077] Finally, in relation to the third corrector C 3, “U pump” corresponds to a voltage control in this example but more generally a current and / or voltage control can be provided.

[0078] Thanks to the invention, it is possible to obtain very high temperature variation rates within the climatic chamber, of the order of 5°C / min, and cycles allowing the passage from ambient or colder temperature to 100°C and vice versa, in stages, with a regulation precision of less than 0.5°C.

[0079] Finally, it is envisaged, within the framework of the invention, that the heat exchange end further comprises / additionally, a device for direct heat exchange with the interior of the enclosure and which is connected to the rest of the fluid circuit of the secondary thermal regulation circuit 9 by means of a controlled valve in order to obtain accelerated temperature adjustment of the enclosure, the controlled valve then cutting off the fluid circuit and leaving the thermoelectric assembly(s) to act in concert with the secondary thermal regulation circuit 9 as described above.

Claims

1. A thermally regulated climate chamber (3) intended to test at least one piece of equipment, the climate chamber (3) having a wall defining an internal space containing a gas and able to receive and contain said at least one piece of equipment to be tested, the internal space being thermally insulated from the environment outside the climate chamber (3), wherein at least one thermoelectric unit (10) is arranged through the wall of the climate chamber (3), each thermoelectric unit (10) having two faces, an internal face (11) located inside the climate chamber and an external face (14) located outside the climate chamber (3), and wherein one of both faces (11, 14), called the cold face, is intended to absorb caloric energy and the other one, called the hot face, is intended to reject caloric energy as a function of the electric current passing through said at least one thermoelectric unit (10), wherein a heat exchange end (4) for an external face (14) of a thermoelectric unit (10) of a secondary thermal regulation circuit (9) is placed in thermal contact with each external face (14) of thermoelectric unit (10) in order to exchange caloric energy between said at least one thermoelectric unit (10) and said secondary thermal regulation circuit (9), the secondary thermal regulation circuit (9) being external to the climate chamber and including a heat-transfer fluid circuit, a cold source (8), a hot source (12), a mixing device (13), a circulation pump (15) and sensors (5a, 5b, 5c, 5d, 6, 7), and wherein a chamber temperature regulation system is configured to control the electric current of said at least one thermoelectric unit (10) and to control at least the mixing device (13) and the circulation pump (15) of the secondary thermal regulation circuit (9) as a function of a chamber temperature setpoint (Tic) and of sensor measurements (5a, 5b, 5c, 5d, 6, 7).

2. The climate chamber according to claim 1, wherein the climate chamber (3) is attached to a movable support of a motion simulator and the movable support can be set in motion by means of joints of said motion simulator.

3. The climate chamber according to claim 1 or claim 2, wherein the temperature of the hot source (12) is adjustable and the chamber temperature regulation system further adjusts the temperature of the hot source (12).

4. The climate chamber according to anyone of claims 1 to 3, wherein the chamber temperature regulation system (3) is configured to regulate the temperature of the external face (14) as a function of the chamber temperature setpoint (Tic) and in such a way that the polarity of the current circulating in said at least one thermoelectric unit (10) is constant, the internal face (11) being a cold face absorbing caloric energy coming from the inside of the climate chamber (3).

5. The climate chamber according to anyone of claims 1 to 4, wherein the chamber temperature regulation system (3) is configured to ensure a continuous flow of the heat-transfer fluid in the heat exchange end (4) for an external face (14) of a thermoelectric unit (10) of the secondary thermal regulation circuit (9).

6. The climate chamber according to anyone of claims 1 to 5, wherein the chamber temperature regulation system is configured to control the heat-transfer fluid flow while avoiding a high-temperature cavitation of the heat-transfer fluid that would be due to a too high speed of the heat-transfer fluid.

7. The climate chamber according to anyone of claims 1 to 6, including at least two thermoelectric units through the climate chamber and the thermoelectric units are electrically connected in parallel.

8. The climate chamber according to anyone of claims 1 to 7, wherein the chamber temperature regulation system includes at least two regulation loops, said at least two regulation loops being a main regulation loop controlling the electric current of said at least one thermoelectric unit (10) and at least one secondary regulation loop controlling the secondary thermal regulation circuit (9).

9. The climate chamber according to claim 8, wherein the secondary regulation loop controlling the secondary thermal regulation circuit (9) includes a hot and cold sharing regulation loop and a flow rate regulation loop.

10. A method for thermal regulation of a climate chamber intended to test at least one piece of equipment, wherein a climate chamber with thermoelectric unit(s) (10) according to anyone of claims 2 to 9 is implemented, the climate chamber (3) being attached to a movable support of a motion simulator and the movable support being able to be set in motion by means of joints of said motion simulator, and wherein a secondary thermal regulation circuit (9) including a heat exchange end (4) for an external face (14) of a thermoelectric unit (10) is further implemented, the heat exchange end (4) is arranged against the external face(s) (14) of the thermoelectric unit(s), the rest of the secondary thermal regulation circuit (9) being arranged out of movable parts of the motion simulator and being connected to the heat exchange end (4) by movable fluid seals passing through the joints of the motion simulator.

11. A kit for installing a thermally regulated climate chamber (3) in a motion simulator, the climate chamber (3) being intended to test at least one piece of equipment, the motion simulator including a movable support set in motion by means of joints of said motion simulator, said kit including: - a climate chamber (3) including a wall defining an internal space able to receive and contain said at least one piece of equipment to be tested, the internal space being able to contain a gas and being thermally insulated from the environment outside the climate chamber, the climate chamber including means for attachment to the movable support, the chamber further including at least one thermoelectric unit (10), said at least one thermoelectric unit (10) being arranged through the wall of the climate chamber (3), each thermoelectric unit (3) having two faces, an internal face (11) located inside the climate chamber (3) and an external face (14) outside the climate chamber (3), and wherein one of both faces, called the cold face, is intended to absorb caloric energy and the other one, called the hot face, is intended to reject caloric energy as a function of the electric current passing through said at least one thermoelectric unit (10), - a secondary thermal regulation circuit (9) including a heat-transfer fluid circuit, means for connection to a cold source (8), a hot source (12), a mixing device (13), a circulation pump (15) and sensors (5a, 5b, 5c, 5d, 6, 7), the heat-transfer fluid circuit having a heat exchange end for an external face (14) of a thermoelectric unit (10) intended to come into thermal contact with an external face (14) of thermoelectric unit (10) in order to exchange caloric energy between said at least one thermoelectric unit (10) and said secondary thermal regulation circuit(9), - movable fluid seals intended to be installed in joints of the motion simulator to allow the circulation of the heat-transfer fluid of the secondary thermal regulation circuit (9) between the heat exchange end (4) that is intended to be installed in the motion simulator against the external face of the thermoelectric unit and the rest of the secondary thermal regulation circuit (9) that is intended to be installed out of the movable parts of the motion simulator, - movable electrical connections intended to be installed in joints of the motion simulator to allow a circulation of electrical current, - a chamber temperature regulation system intended to control the electric current of said at least one thermoelectric unit (10) and to control at least the mixing device (13) and the circulation pump (15) of the secondary thermal regulation circuit (9) as a function of a chamber temperature setpoint (Tic) and of sensor measurements (5a, 5b, 5c, 5d, 6, 7).