Thermal management control method and system, and operating machine

Abstract

A thermal management control method, comprising: S110, acquiring a current temperature value of a medium to be cooled; S120, on the basis of the current temperature value and a target temperature value, determining a current temperature difference of the medium, the current temperature difference being the difference between the current temperature value and the target temperature value; S130, on the basis of the current temperature difference and a temperature regulation model, determining a current target cooling capacity of the medium, wherein the temperature regulation model is obtained after training has been performed on the basis of temperature difference samples and target cooling capacity samples of the medium during adjustment of the current temperature difference; S140, cooling the medium on the basis of the current target cooling capacity; and S150, when the current temperature difference changes, controlling the medium to maintain the current cooling capacity, until the current temperature difference changes to a boundary value in a temperature range corresponding to the current cooling capacity in the temperature regulation model. Further disclosed are a thermal management control system and an operating machine. Repeated adjustment processes can be avoided, solving the problem of overly frequent adjustments in thermal management systems.

Description

Thermal management control method, control system and operating machinery Technical Field

[0001] The present application relates to the field of thermal management technology, and in particular to a thermal management control method, a control system, and an operating machine.

[0002] Background of the Invention

[0003] Traditional work machines, such as traditional excavators, are powered by fuel engines. However, fuel engines have high fuel consumption, high operating costs, and severe emissions and noise pollution. As a result, work machines are gradually moving towards electric machines. For electric work machines, such as electric loaders, air conditioning systems and battery thermal management systems, which control the temperature of the power batteries, are crucial for ensuring safety, efficiency, and comfort.

[0004] Air conditioning systems and battery thermal management systems (hereinafter collectively referred to as thermal management systems) are similar in that both require the use of the cooling capacity of the refrigerant to cool the air or battery coolant (hereinafter collectively referred to as the cooled medium). During operation, the thermal management system in the prior art mainly controls the cooling capacity of the refrigerant in real time by real-time monitoring of the temperature of the cooled medium. As long as the temperature of the cooled medium increases, the cooling capacity of the refrigerant will be immediately increased, and as long as the temperature of the cooled medium decreases, the cooling capacity of the refrigerant will be immediately reduced. However, the heat exchange process between the refrigerant and the cooled medium requires a certain amount of time, which can easily cause the adjustment process to be repeated, resulting in too frequent adjustments to the thermal management system.

[0005] Therefore, how to solve the problem of over-frequent adjustment of the thermal management system in the prior art has become an important technical problem to be solved by those skilled in the art.

[0006] Summary of the Invention

[0007] The present application provides a thermal management control method, a control system, and an operating machine to solve the defect of overly frequent adjustment of the thermal management system in the prior art.

[0008] The present application provides a thermal management control method for controlling a thermal management system, comprising:

[0009] Get the current temperature value of the cooled medium;

[0010] Determining a current temperature difference of the cooled medium according to the current temperature value and the target temperature value, wherein the current temperature difference is a difference between the current temperature value and the target temperature value;

[0011] determining a current target cooling capacity for the cooled medium based on the current temperature difference and a temperature control model, wherein the temperature control model is obtained by training temperature difference samples and target cooling capacity samples of the cooled medium when the current temperature difference is adjusted;

[0012] refrigerating the cooled medium according to the current target cooling capacity;

[0013] When the current temperature difference changes, the cooling capacity of the cooled medium is controlled to maintain the current cooling capacity until the current temperature difference is adjusted to a boundary value of a temperature range corresponding to the current cooling capacity in the temperature control model.

[0014] According to a thermal management control method provided by the present application, the temperature control model includes a first temperature control model and a second temperature control model. The first temperature control model is obtained by training the target cooling capacity samples and the temperature difference samples of the cooled medium when the current temperature difference shows a decreasing trend. The second temperature control model is obtained by training the target cooling capacity samples and the temperature difference samples of the cooled medium when the current temperature difference shows an increasing trend.

[0015] When the current temperature difference changes, controlling the cooling capacity of the cooled medium to maintain the current cooling capacity until the current temperature difference is adjusted to a boundary value of a temperature range corresponding to the current cooling capacity in the temperature control model includes:

[0016] When the current temperature difference shows a decreasing trend, controlling the cooling capacity of the cooled medium to maintain the current cooling capacity until the current temperature difference decreases to a lower boundary value of the temperature range corresponding to the current cooling capacity in the first temperature control model, and determining a current target cooling capacity for the cooled medium based on the current temperature difference and the first temperature control model;

[0017] When the current temperature difference shows an increasing trend, the cooling capacity of the cooled medium is controlled to maintain the current cooling capacity until the current temperature difference increases to the upper boundary value of the temperature range corresponding to the current cooling capacity in the second temperature control model, and the current target cooling capacity of the cooled medium is determined based on the current temperature difference and the second temperature control model.

[0018] According to a thermal management control method provided by the present application, the first temperature control model and the second temperature control model are piecewise constant functions.

[0019] According to a thermal management control method provided by the present application, the thermal management system includes a compressor;

[0020] Refrigerating the cooled medium according to the current target cooling capacity includes:

[0021] determining a current target speed value of the compressor according to the current target cooling capacity;

[0022] The operating speed of the compressor is controlled according to the current target speed value.

[0023] According to a thermal management control method provided by the present application, the cooled medium includes indoor air and a battery coolant for cooling the battery;

[0024] The thermal management system further includes a first heat exchange unit for exchanging heat and cooling the indoor air and a second heat exchange unit for exchanging heat and cooling the battery coolant. The first heat exchange unit and the second heat exchange unit are arranged in parallel.

[0025] According to a thermal management control method provided by the present application, when the indoor air and the battery coolant require heat exchange and temperature reduction simultaneously, determining the current target cooling capacity of the cooled medium based on the current temperature difference and the temperature control model includes:

[0026] determining a first current target cooling capacity for the indoor air according to the current temperature difference of the indoor air;

[0027] determining a second current target cooling capacity for the battery coolant according to the current temperature difference of the battery coolant;

[0028] Refrigerating the cooled medium according to the current target cooling capacity includes:

[0029] determining a first current target speed value of the compressor according to the first current target cooling capacity;

[0030] determining a second current target speed value of the compressor according to the second current target cooling capacity;

[0031] determining a total current target speed value of the compressor according to the first current target speed value and the second current target speed value;

[0032] The operating speed of the compressor is controlled according to the total current target speed value.

[0033] According to a thermal management control method provided by the present application, a first expansion valve is provided on the branch where the first heat exchange unit is located, and a second expansion valve is provided on the branch where the second heat exchange unit is located, and both the first expansion valve and the second expansion valve can achieve the functions of adjustable opening and complete shutoff;

[0034] The thermal management control method further includes:

[0035] obtaining a current superheat degree of the refrigerant at a refrigerant outlet of the second heat exchange unit;

[0036] The opening degree of the second expansion valve is controlled according to the current superheat degree and the target superheat degree.

[0037] According to a thermal management control method provided by the present application, the first temperature control model includes at least a first temperature difference interval, a second temperature difference interval, a third temperature difference interval, a first target cooling capacity corresponding to the first temperature difference interval, a second target cooling capacity corresponding to the second temperature difference interval, and a third target cooling capacity corresponding to the third temperature difference interval;

[0038] The upper boundary value of the first temperature difference interval is equal to the lower boundary value of the second temperature difference interval, the upper boundary value of the second temperature difference interval is equal to the lower boundary value of the third temperature difference interval, the first target cooling capacity is less than the second target cooling capacity, and the second target cooling capacity is less than the third target cooling capacity.

[0039] According to a thermal management control method provided by the present application, the second temperature control model includes at least the first temperature difference interval, the second temperature difference interval, the third temperature difference interval, a fourth target cooling capacity corresponding to the first temperature difference interval, a fifth target cooling capacity corresponding to the second temperature difference interval, and a sixth target cooling capacity corresponding to the third temperature difference interval;

[0040] The fourth target cooling capacity is smaller than the fifth target cooling capacity, the fifth target cooling capacity is smaller than the sixth target cooling capacity, the first target cooling capacity is larger than the fourth target cooling capacity, the second target cooling capacity is larger than the fifth target cooling capacity, and the third target cooling capacity is larger than the sixth target cooling capacity.

[0041] The present application also provides a thermal management control system, including a controller and a thermal management system, wherein the thermal management system includes:

[0042] A refrigerant circuit includes a compressor, a condenser, a first expansion valve, a second expansion valve, a first heat exchange unit, a second heat exchange unit, a temperature and pressure sensor, and a first temperature sensor. The exhaust end of the compressor is connected to the inlet of the condenser. The first heat exchange unit has a first channel for circulating refrigerant and a second channel for circulating air. The second heat exchange unit has a third channel for circulating refrigerant and a fourth channel for circulating battery coolant. The inlet of the first channel is connected to the inlet of the third channel and then to the outlet of the condenser. The outlet of the first channel is connected to the outlet of the third channel and then to the suction end of the compressor. The first expansion valve is arranged at the inlet of the first channel, the second expansion valve is arranged at the inlet of the third channel, the temperature and pressure sensor is arranged at the outlet of the third channel, and the first temperature sensor is arranged at the outlet of the second channel.

[0043] a battery cooling circuit, comprising a heat exchange portion, a power pump, and a second temperature sensor; the heat exchange portion is configured to contact the battery, the heat exchange portion having an inlet and an outlet for inlet and outlet of the battery coolant, the inlet of the heat exchange portion being connected to the outlet of the fourth channel, the outlet of the heat exchange portion being connected to the inlet of the power pump, and the outlet of the power pump being connected to the inlet of the fourth channel; and the second temperature sensor being disposed at the inlet of the heat exchange portion;

[0044] The first temperature sensor, the temperature and pressure sensor, the second temperature sensor, the first expansion valve, the second expansion valve and the compressor are all electrically connected to the controller, and the controller is used to execute the above-mentioned thermal management control method.

[0045] The present application also provides a working machine, comprising a controller, wherein the controller is configured to execute the above-mentioned thermal management control method;

[0046] Alternatively, the work machine includes the thermal management control system described above.

[0047] The thermal management control method provided in this application is used to control a thermal management system. The thermal management control method obtains the current temperature value of the cooled medium; determines the current temperature difference of the cooled medium based on the current temperature value and the target temperature value, where the current temperature difference is the difference between the current temperature value and the target temperature value; determines the current target cooling capacity of the cooled medium based on the current temperature difference and a temperature control model, where the temperature control model is obtained by training temperature difference samples and target cooling capacity samples of the cooled medium when the current temperature difference is adjusted; and then cools the cooled medium according to the current target cooling capacity. When the current temperature difference changes, the cooling capacity of the cooled medium is controlled to maintain the current cooling capacity until the current temperature difference is adjusted to the boundary value of the temperature range corresponding to the current cooling capacity in the temperature control model. With this arrangement, in the temperature control model, a certain value of cooling capacity corresponds to a certain temperature range, that is, when the temperature of the cooled medium is within a certain temperature range, the corresponding cooling capacity demand is the same. During the thermal management control process, when the current temperature difference of the cooled medium changes, the cooling capacity of the cooled medium is not immediately increased or decreased. Instead, the cooling capacity of the cooled medium must be controlled to maintain the current cooling capacity. If the temperature of the cooled medium cannot be controlled within the temperature range corresponding to the current cooling capacity, the cooling capacity of the cooled medium is adjusted according to the temperature control model when the temperature of the cooled medium changes to the boundary value of the temperature range corresponding to the current cooling capacity. During the control of the thermal management system, a certain amount of time is reserved for the heat exchange process between the refrigerant and the cooled medium, which can effectively avoid repeated adjustments and solve the problem of overly frequent adjustments in thermal management systems in the prior art.

[0048] BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0050] FIG1 is a flow chart of a thermal management control method provided by the present application;

[0051] FIG2 is a flow chart of another thermal management control method provided by the present application;

[0052] FIG3 is a flow chart of another thermal management control method provided by the present application;

[0053] FIG4 is a schematic diagram of a first temperature control model and a second temperature control model provided by the present application when the cooled medium is indoor air;

[0054] FIG5 is a schematic diagram of a first temperature control model and a second temperature control model provided by the present application when the cooling medium is a battery coolant and the power battery is in a charging state;

[0055] FIG6 is a schematic diagram of a first temperature control model and a second temperature control model provided by the present application when the cooling medium is a battery coolant and the power battery is in a discharge state;

[0056] FIG7 is a schematic structural diagram of the thermal management system provided in this application.

[0057] Reference numerals:

[0058] 1. Compressor; 2. Condenser; 3. First expansion valve; 4. Second expansion valve; 5. First heat exchange unit; 6. Second heat exchange unit; 7. Temperature and pressure sensor; 8. First temperature sensor; 9. Heat exchange unit; 10. Power pump; 11. Second temperature sensor.

[0059] Modes for Carrying Out the Invention

[0060] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0061] The thermal management control method of the present application is described below with reference to FIG. 1 to FIG. 7 .

[0062] As shown in FIG1 and FIG7 , the thermal management control method provided in the embodiment of the present application can be executed by a control system of the thermal management system or other independent control devices.

[0063] The thermal management control method in this embodiment mainly includes the following steps:

[0064] Step S110: Acquire the current temperature value of the cooled medium.

[0065] The thermal management control method is used to control the thermal management system to adjust the temperature of the cooling medium of the thermal management system. The thermal management system can be a battery thermal management system or an air conditioning system.

[0066] In the battery thermal management system, the cooling medium is battery coolant, which is cooled by a refrigerant and then used to cool the power batteries. The battery thermal management system includes a heat exchange unit 9 for heat exchange between the power batteries. To obtain the temperature of the battery coolant, a temperature sensor can be installed at the liquid inlet of the heat exchange unit 9 to measure the temperature of the battery coolant before it enters the heat exchange unit 9.

[0067] In an air conditioning system, the cooling medium is the air surrounding the system's evaporator, such as indoor air. The refrigerant cools the air surrounding the evaporator, which in turn cools items within the evaporator. To obtain the temperature of the air surrounding the evaporator, a temperature sensor can be installed at the evaporator's air outlet to measure the temperature.

[0068] The temperature sensor is electrically connected to the control system or the control device, and the control system or the control device can obtain the current temperature value of the cooled medium in real time.

[0069] Step S120: Determine a current temperature difference of the cooled medium according to the current temperature value and the target temperature value, where the current temperature difference is the difference between the current temperature value and the target temperature value.

[0070] Specifically, the current temperature value of the cooled medium can be collected according to a preset time length, for example, data is collected every a seconds. For example, the temperature collected at the current moment t is recorded as the current temperature value, and the temperature at the previous moment is the temperature collected at moment ta, which can also be understood as the temperatures collected twice adjacently.

[0071] A current temperature difference value may be determined according to the current temperature value and the target temperature value, where the current temperature difference value is the difference between the current temperature value and the target temperature value.

[0072] The temperature difference at the previous moment can be determined based on the temperature at the previous moment and the target temperature value. The temperature difference at the previous moment is the difference between the temperature at the previous moment and the target temperature value.

[0073] Step S130: Determine the current target cooling capacity of the cooled medium according to the current temperature difference and the temperature control model. The temperature control model is obtained by training the temperature difference samples and the target cooling capacity samples of the cooled medium when the current temperature difference is adjusted.

[0074] The above temperature control model is obtained by collecting a number of target cooling capacity samples and temperature difference samples and training these samples.

[0075] The above temperature control model can be understood as a function that inputs the current temperature difference and outputs the current target cooling capacity of the cooled medium.

[0076] Step S140: refrigerate the cooled medium according to the current target cooling capacity.

[0077] After the current target cooling capacity is determined, the cooled medium may be cooled according to the determined current target cooling capacity.

[0078] Step S150 : When the current temperature difference changes, the cooling capacity of the cooled medium is controlled to maintain the current cooling capacity until the current temperature difference is adjusted to the boundary value of the temperature range corresponding to the current cooling capacity in the temperature control model.

[0079] If the current temperature difference differs from the previous temperature difference, it indicates a change. When a change is detected, the cooling capacity of the cooled medium is first controlled to maintain the current cooling capacity. The cooling capacity of the cooled medium is not immediately reduced. Instead, the cooling capacity of the cooled medium is monitored for further changes. If the current temperature difference continues to change and cannot be controlled within the temperature range corresponding to the current cooling capacity, the cooling capacity of the cooled medium is adjusted according to the temperature control model when the temperature of the cooled medium reaches the boundary of the temperature range corresponding to the current cooling capacity.

[0080] With such a setting, in the temperature control model, a certain value of cooling capacity corresponds to a certain temperature range, that is, when the temperature of the cooled medium is within a certain temperature range, the corresponding cooling capacity demand is the same. During the thermal management control process, when the current temperature difference of the cooled medium changes, the cooling capacity of the cooled medium will not be immediately controlled to increase or decrease. It is necessary to first control the cooling capacity of the cooled medium to maintain the current cooling capacity. If the temperature of the cooled medium cannot be controlled within the temperature range corresponding to the current cooling capacity, then when the temperature of the cooled medium changes to the boundary value of the temperature range corresponding to the current cooling capacity, the cooling capacity of the cooled medium will be adjusted according to the temperature control model. In the process of controlling the thermal management system, a certain amount of time is reserved for the heat exchange process between the refrigerant and the cooled medium, which can effectively avoid the repetition of the adjustment process and solve the problem of excessive adjustment of the thermal management system in the prior art.

[0081] In a further embodiment, the temperature control model includes a first temperature control model and a second temperature control model, both of which are obtained by collecting a number of target cooling capacity samples and temperature difference samples and training these samples. Specifically, when constructing the first temperature control model, the collection of target cooling capacity samples and temperature difference samples is primarily based on simulation experiments of control when the current temperature difference of the cooled medium is decreasing. When constructing the second temperature control model, the collection of target cooling capacity samples and temperature difference samples is primarily based on simulation experiments of control when the current temperature difference of the cooled medium is increasing, thereby ensuring representativeness and accuracy.

[0082] In the above step S150, as shown in FIG2 , the following steps are included:

[0083] Step S151: If the current temperature difference shows a decreasing trend, the cooling capacity of the cooled medium is controlled to maintain the current cooling capacity until the current temperature difference is reduced to the lower boundary value of the temperature range corresponding to the current cooling capacity in the first temperature control model, and the current target cooling capacity of the cooled medium is determined based on the current temperature difference and the first temperature control model.

[0084] Step S152: If the current temperature difference shows an increasing trend, the cooling capacity of the cooled medium is controlled to maintain the current cooling capacity until the current temperature difference increases to the upper boundary value of the temperature range corresponding to the current cooling capacity in the second temperature control model, and the current target cooling capacity of the cooled medium is determined based on the current temperature difference and the second temperature control model.

[0085] The first temperature control model and the second temperature control model can both be understood as a function, which inputs the current temperature difference and outputs the current target cooling capacity of the cooled medium.

[0086] Furthermore, the first temperature control model is trained based on target cooling capacity samples and temperature difference samples when the current temperature difference of the cooled medium is decreasing. The second temperature control model is trained based on target cooling capacity samples and temperature difference samples when the current temperature difference of the cooled medium is increasing. Adjusting the cooling capacity based on the changing trend of the current temperature difference of the cooled medium is more accurate and can further avoid repeated adjustments.

[0087] In this embodiment, the thermal management system includes a compressor 1 for circulating a refrigerant. During the refrigerant circulation process, the refrigerant transfers cold energy to a cooled medium, thereby reducing the temperature of the cooled medium.

[0088] The cooling capacity of the cooled medium is closely related to the rotation speed of the compressor 1, and is in a linear relationship. The specific relationship can be calculated based on the configuration and model of the selected compressor 1. Step S140: Refrigerating the cooled medium according to the current target cooling capacity, as shown in FIG3, includes:

[0089] Step S141: The current target speed value of the compressor may be determined according to the current target cooling capacity.

[0090] Step S142: The current target speed value is then used to control the operating speed of the compressor.

[0091] In the embodiment of the present application, the first temperature control model and the second temperature control model are piecewise constant functions.

[0092] The first temperature control model includes at least a first temperature difference interval, a second temperature difference interval, a third temperature difference interval, a first target cooling capacity, a second target cooling capacity, and a third target cooling capacity. The first target cooling capacity corresponds to the first temperature difference interval. When the current temperature difference is within the first temperature difference interval, the current target cooling capacity is the first target cooling capacity. The second target cooling capacity corresponds to the second temperature difference interval. When the current temperature difference is within the second temperature difference interval, the current target cooling capacity is the second target cooling capacity. The third target cooling capacity corresponds to the third temperature difference interval. When the current temperature difference is within the third temperature difference interval, the current target cooling capacity is the third target cooling capacity.

[0093] Among them, the upper boundary value of the first temperature difference interval is equal to the lower boundary value of the second temperature difference interval, the upper boundary value of the second temperature difference interval is equal to the lower boundary value of the third temperature difference interval, the first target cooling capacity is less than the second target cooling capacity, and the second target cooling capacity is less than the third target cooling capacity.

[0094] Accordingly, the second temperature control model includes at least a first temperature difference interval, a second temperature difference interval, a third temperature difference interval, a fourth target cooling capacity, a fifth target cooling capacity, and a sixth target cooling capacity. The fourth target cooling capacity corresponds to the first temperature difference interval. When the current temperature difference is within the first temperature difference interval, the current target cooling capacity is the fourth target cooling capacity. The fifth target cooling capacity corresponds to the second temperature difference interval. When the current temperature difference is within the second temperature difference interval, the current target cooling capacity is the fifth target cooling capacity. The sixth target cooling capacity corresponds to the third temperature difference interval. When the current temperature difference is within the third temperature difference interval, the current target cooling capacity is the sixth target cooling capacity.

[0095] The fourth target cooling capacity is smaller than the fifth target cooling capacity, the fifth target cooling capacity is smaller than the sixth target cooling capacity, the first target cooling capacity is larger than the fourth target cooling capacity, the second target cooling capacity is larger than the fifth target cooling capacity, and the third target cooling capacity is larger than the sixth target cooling capacity.

[0096] Specifically, when the cooled medium is indoor air, the first temperature control model and the second temperature control model refer to FIG. 4 , in which the target speed value of the compressor is used instead of the target cooling capacity of the cooled medium.

[0097] The target temperature value of the indoor air can be set to 18°C-32°C. When the compressor 1 starts running, the current target speed value of the compressor 1 is determined according to the first temperature control model. At this time, the current temperature difference may increase or decrease.

[0098] If the current temperature difference is greater than 2°C, the current target speed value of compressor 1 is controlled to be 2000 rpm. If the current temperature difference increases, the current target speed value of compressor 1 remains unchanged. If the current temperature difference decreases, when the current temperature difference is less than 2°C, the current target speed value of compressor 1 is controlled to be 1400 rpm.

[0099] If the current temperature difference is less than or equal to 2°C and greater than -2°C, the current target speed value of compressor 1 is controlled to be 1400 rpm. If the current temperature difference increases, when the current temperature difference is greater than or equal to 4°C, the current target speed value of compressor 1 is controlled to be 2000 rpm. If the current temperature difference decreases, when the current temperature difference is less than -2°C, the current target speed value of compressor 1 is controlled to be 1000 rpm.

[0100] If the current temperature difference is less than or equal to -2°C and greater than -10°C, the current target speed value of compressor 1 is controlled to be 1000 rpm. If the current temperature difference increases, when the current temperature difference is greater than or equal to 2°C, the current target speed value of compressor 1 is controlled to be 1400 rpm. If the current temperature difference decreases, when the current temperature difference is less than -10°C, the current target speed value of compressor 1 is controlled to be 0.

[0101] If the current temperature difference is less than or equal to 0°C, the speed value of compressor 1 is controlled to be 0. If the current temperature difference increases, the current target speed value of compressor 1 will be controlled to be 1000rpm only when the current temperature difference is greater than or equal to -2°C.

[0102] When the cooling medium is battery coolant, since the battery requires thermal management in both charging and discharging states, corresponding first and second temperature control models need to be configured respectively, with specific reference to FIG5 and FIG6 .

[0103] When the battery is in charging state, the target temperature value of the battery coolant can be set to 15°C. When the compressor 1 starts running, the current target speed value of the compressor 1 is determined according to the first temperature control model. At this time, the current temperature difference may increase or decrease.

[0104] If the current temperature difference is greater than or equal to 3°C, the current target speed value of compressor 1 is controlled to be 3000 rpm. If the current temperature difference increases, the current target speed value of compressor 1 remains unchanged. If the current temperature difference decreases, when the current temperature difference is less than 3°C, the current target speed value of compressor 1 is controlled to be 2100 rpm.

[0105] If the current temperature difference is less than 3°C and greater than 2°C, the current target speed value of compressor 1 is controlled to be 2100 rpm. If the current temperature difference increases, when the current temperature difference is greater than or equal to 4°C, the current target speed value of compressor 1 is controlled to be 3000 rpm. If the current temperature difference decreases, when the current temperature difference is less than or equal to 2°C, the current target speed value of compressor 1 is controlled to be 1200 rpm.

[0106] If the current temperature difference is less than or equal to 2°C and greater than 0°C, the current target speed value of compressor 1 is controlled to be 1200 rpm. If the current temperature difference increases, when the current temperature difference is greater than or equal to 3°C, the current target speed value of compressor 1 is controlled to be 2100 rpm. If the current temperature difference decreases, when the current temperature difference is less than or equal to 0°C, the current target speed value of compressor 1 is controlled to be 0.

[0107] If the current temperature difference is less than or equal to 0°C, the speed value of compressor 1 is controlled to be 0. If the current temperature difference increases, the current target speed value of compressor 1 will be controlled to be 1200rpm only when the current temperature difference is greater than or equal to 2°C.

[0108] Accordingly, when the battery is in a discharging state, the target temperature value of the battery coolant can be set to 18°C. When the compressor 1 starts running, the current target speed value of the compressor 1 is determined according to the first temperature control model. At this time, the current temperature difference may increase or decrease.

[0109] If the current temperature difference is greater than or equal to 2°C, the current target speed value of compressor 1 is controlled to be 2000 rpm. If the current temperature difference increases, the current target speed value of compressor 1 remains unchanged. If the current temperature difference decreases, when the current temperature difference is less than 2°C, the current target speed value of compressor 1 is controlled to be 1500 rpm.

[0110] If the current temperature difference is less than 2°C and greater than 1°C, the current target speed value of compressor 1 is controlled to be 1500 rpm. If the current temperature difference increases, when the current temperature difference is greater than or equal to 3°C, the current target speed value of compressor 1 is controlled to be 2000 rpm. If the current temperature difference decreases, when the current temperature difference is less than or equal to 1°C, the current target speed value of compressor 1 is controlled to be 1000 rpm.

[0111] If the current temperature difference is less than or equal to 1°C and greater than 0°C, the current target speed value of compressor 1 is controlled to be 1000 rpm. If the current temperature difference increases, when the current temperature difference is greater than or equal to 2°C, the current target speed value of compressor 1 is controlled to be 2000 rpm. If the current temperature difference decreases, when the current temperature difference is less than or equal to 0°C, the current target speed value of compressor 1 is controlled to be 0.

[0112] If the current temperature difference is less than or equal to 0°C, the speed value of compressor 1 is controlled to be 0. If the current temperature difference increases, the current target speed value of compressor 1 will be controlled to be 1000rpm only when the current temperature difference is greater than or equal to 1°C.

[0113] In some embodiments, the thermal management system includes both a battery thermal management system and an air-conditioning system. In this case, the cooled medium includes indoor air and battery coolant. The thermal management system includes a first heat exchange unit 5 and a second heat exchange unit 6. The first heat exchange unit 5 is used for heat exchange and cooling of the indoor air, and the second heat exchange unit 6 is used for heat exchange and cooling of the battery coolant.

[0114] The first heat exchange unit 5 and the second heat exchange unit 6 are arranged in parallel. A first expansion valve 3 and a second expansion valve 4 are respectively installed at the refrigerant inlet of the first heat exchange unit 5 and the refrigerant inlet of the second heat exchange unit 6. Both the first expansion valve 3 and the second expansion valve 4 can be adjusted in opening and completely shut off. By controlling the two expansion valves, the battery thermal management system can operate independently, the air conditioning system can operate independently, or both the battery thermal management system and the air conditioning system can operate simultaneously.

[0115] For the battery thermal management system operating alone mode and the air conditioning system operating alone mode, the speed of the compressor 1 can be directly controlled according to the above thermal management control method.

[0116] In the mode where the battery thermal management system and the air-conditioning system operate simultaneously, the indoor air and the battery coolant need to exchange heat and cool down at the same time. At this time, it is necessary not only to comprehensively consider the temperature parameters of the battery coolant and the temperature parameters of the indoor air to determine the speed of compressor 1, but also to allocate the refrigerant flow according to the respective cooling requirements of the battery thermal management system and the air-conditioning system.

[0117] In a specific embodiment, a first current target cooling capacity for indoor air and a second current target cooling capacity for battery coolant can be determined respectively according to steps 110 to 150 above. The first current target cooling capacity and the second current target cooling capacity represent the cooling capacity requirements of the battery thermal management system and the cooling capacity requirements of the air conditioning system, respectively.

[0118] Then, the first current target speed value and the second current target speed value are determined based on the first current target cooling capacity and the second current target cooling capacity, respectively. The first current target speed value and the second current target speed value represent the battery thermal management system's requirements for the compressor 1 speed and the air-conditioning system's requirements for the compressor 1 speed, respectively.

[0119] Then, based on the first current target speed value and the second current target speed value, the total current target speed value of the compressor 1 is determined. Specifically, the total current target speed value of the compressor 1 is the sum of the first current target speed value and the second current target speed value.

[0120] The operating speed of the compressor 1 can be controlled according to the total current target speed value.

[0121] When distributing the flow of refrigerant, it is necessary to first obtain the current superheat of the refrigerant at the refrigerant outlet of the second heat exchange unit 6, and control the opening of the second expansion valve 4 according to the current superheat and the target superheat, so as to control the flow of the refrigerant in the second heat exchange unit 6 and allow the remaining refrigerant to enter the first heat exchange unit 5.

[0122] Specifically, the target superheat can be set to 5-8°C, and a temperature and pressure sensor 7 is installed at the refrigerant outlet of the second heat exchange unit 6. The current superheat is calculated based on the data obtained by the temperature and pressure sensor 7. It should be noted that the technical principle of calculating the current superheat based on the data obtained by the temperature and pressure sensor 7 is a mature existing technology. If the current superheat is less than 5°C, the opening of the second expansion valve 4 is controlled to decrease by 24ps reference units until the current superheat reaches the range of 5-8°C. If the current superheat is greater than 8°C, the opening of the second expansion valve 4 is controlled to increase by 24ps reference units until the current superheat reaches the range of 5-8°C.

[0123] On the other hand, based on the same general application concept, the embodiment of the present application further provides a thermal management control system. The thermal management control system described below and the thermal management control method described above can refer to each other.

[0124] An embodiment of the present application provides a thermal management control system, including a controller and a thermal management system.

[0125] Specifically, the thermal management system includes a refrigerant circuit and a battery cooling circuit, refer to FIG. 7 .

[0126] The refrigerant circuit includes a compressor 1, a condenser 2, a first expansion valve 3, a second expansion valve 4, a first heat exchange unit 5, a second heat exchange unit 6, a temperature and pressure sensor 7, and a first temperature sensor 8. The exhaust port of compressor 1 is connected to the inlet of condenser 2. The first heat exchange unit 5 has a first channel for refrigerant circulation and a second channel for air circulation. The second heat exchange unit 6 has a third channel for refrigerant circulation and a fourth channel for battery coolant circulation. The inlet of the first channel is connected to the inlet of the third channel, and then to the outlet of condenser 2. The outlet of the first channel is connected to the outlet of the third channel, and then to the intake port of compressor 1. The first expansion valve 3 is located at the inlet of the first channel, the second expansion valve 4 is located at the inlet of the third channel, the temperature and pressure sensor 7 is located at the outlet of the third channel, and the first temperature sensor 8 is located at the outlet of the second channel.

[0127] The battery cooling circuit includes a heat exchange part 9, a power pump 10 and a second temperature sensor 11. The heat exchange part 9 is used to contact the battery. The heat exchange part 9 has an inlet and an outlet for the battery coolant to enter and exit. The inlet of the heat exchange part 9 is connected to the outlet of the fourth channel, the outlet of the heat exchange part 9 is connected to the inlet of the power pump 10, the outlet of the power pump 10 is connected to the inlet of the fourth channel, and the second temperature sensor 11 is arranged at the inlet of the heat exchange part 9.

[0128] The first temperature sensor 8 , the temperature and pressure sensor 7 , the second temperature sensor 11 , the first expansion valve 3 , the second expansion valve 4 and the compressor 1 are all electrically connected to a controller, which is used to execute the thermal management control method provided in any of the above embodiments.

[0129] The first heat exchange unit 5 and the second heat exchange unit 6 can be used to cool the indoor environment and the power battery respectively. By controlling the first expansion valve 3 and the second expansion valve 4, it is possible to control the separate cooling of the indoor environment, the separate cooling of the power battery, and the simultaneous cooling of the indoor environment and the power battery.

[0130] The first temperature sensor 8 and the second temperature sensor 11 may detect the temperature of the indoor air and the temperature of the battery coolant, respectively.

[0131] The current superheat of the refrigerant at the outlet of the third channel of the second heat exchange unit 6 can be determined by using the temperature and pressure sensor 7 .

[0132] The thermal management control system in the embodiment of the present application can select a large-displacement, low-speed compressor 1, and use one compressor 1 to provide cooling capacity for indoor air and power batteries, reducing the number of compressors 1 set up, improving integration, and helping to reduce the cost of the thermal management control system.

[0133] The refrigerant condenses and releases heat in condenser 2, requiring a cooling fan to facilitate heat dissipation and cooling of condenser 2. In a further embodiment, the electric working machine further comprises an electronically controlled motor thermal management system and a hydraulic oil cooling system. The radiator of the electronically controlled motor thermal management system, the radiator of the hydraulic oil cooling system, and the aforementioned condenser 2 can be centrally located. A single cooling fan can be used to facilitate the circulation of surrounding air, allowing air to flow sequentially through the radiator of the hydraulic oil cooling system, the radiator of the electronically controlled motor thermal management system, and condenser 2. This reduces the number of cooling fans used, further reduces the cost of the thermal management control system, and improves the utilization rate of the cooling fans.

[0134] On the other hand, based on the same general application concept, embodiments of the present application further provide a work machine capable of executing the control method of the thermal management system provided in any of the above embodiments, or including the thermal management system provided in any of the above embodiments, and having the advantage of a simple structure. The derivation process of the beneficial effects of the work machine in the embodiments of the present application is generally similar to the derivation process of the beneficial effects of the above thermal management control method or thermal management control system, and thus will not be repeated here.

[0135] In the embodiments of the present application, the type of the working machine is not limited. For example, the working machine may be an electric excavator, an electric crane, an electric loader, etc.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A thermal management control method for controlling a thermal management system, comprising: Get the current temperature value of the cooled medium; Determine a current temperature difference of the cooled medium according to the current temperature value and the target temperature value, wherein the current temperature difference is a difference between the current temperature value and the target temperature value; Determining a current target cooling capacity of the cooled medium according to the current temperature difference and a temperature control model, wherein the temperature control model is obtained after training the temperature difference samples and the target cooling capacity samples of the cooled medium when the current temperature difference is adjusted; Refrigerating the cooled medium according to the current target refrigeration capacity; When the current temperature difference changes, the cooling capacity of the cooled medium is controlled to maintain the current cooling capacity until the current temperature difference is adjusted to a boundary value of a temperature range corresponding to the current cooling capacity in the temperature control model.

2. The thermal management control method according to claim 1, wherein: The temperature control model includes a first temperature control model and a second temperature control model, wherein the first temperature control model is obtained by training the target cooling capacity samples and the temperature difference samples of the cooled medium when the current temperature difference shows a decreasing trend, and the second temperature control model is obtained by training the target cooling capacity samples and the temperature difference samples of the cooled medium when the current temperature difference shows an increasing trend; When the current temperature difference changes, controlling the cooling capacity of the cooled medium to maintain the current cooling capacity until the current temperature difference is adjusted to a boundary value of the temperature range corresponding to the current cooling capacity in the temperature control model includes: When the current temperature difference shows a decreasing trend, controlling the cooling capacity of the cooled medium to maintain the current cooling capacity until the current temperature difference decreases to the lower boundary value of the temperature range corresponding to the current cooling capacity in the first temperature control model, and determining the current target cooling capacity of the cooled medium according to the current temperature difference and the first temperature control model; When the current temperature difference shows an increasing trend, the cooling capacity of the cooled medium is controlled to maintain the current cooling capacity until the current temperature difference increases to the upper boundary value of the temperature range corresponding to the current cooling capacity in the second temperature control model, and the current target cooling capacity of the cooled medium is determined based on the current temperature difference and the second temperature control model.

3. The thermal management control method according to claim 2, wherein: The first temperature control model and the second temperature control model are piecewise constant functions.

4. The thermal management control method according to any one of claims 1 to 3, wherein: The thermal management system includes a compressor; Refrigerating the cooled medium according to the current target refrigeration capacity includes: Determining a current target speed value of the compressor according to the current target cooling capacity; The operating speed of the compressor is controlled according to the current target speed value.

5. The thermal management control method according to claim 4, wherein: The cooled medium includes indoor air and a battery coolant for cooling the battery; The thermal management system further includes a first heat exchange unit for exchanging heat and cooling the indoor air and a second heat exchange unit for exchanging heat and cooling the battery coolant, wherein the first heat exchange unit and the second heat exchange unit are arranged in parallel.

6. The thermal management control method according to claim 5, wherein: When the indoor air and the battery coolant need to exchange heat and cool down at the same time, determining the current target cooling capacity of the cooled medium according to the current temperature difference and the temperature control model includes: determining a first current target cooling capacity for the indoor air according to the current temperature difference of the indoor air; determining a second current target cooling capacity for the battery coolant according to a current temperature difference of the battery coolant; Refrigerating the cooled medium according to the current target refrigeration capacity includes: determining a first current target speed value of the compressor according to the first current target cooling capacity; determining a second current target speed value of the compressor according to the second current target cooling capacity; determining a total current target speed value of the compressor according to the first current target speed value and the second current target speed value; The operating speed of the compressor is controlled according to the total current target speed value.

7. The thermal management control method according to claim 6, wherein: A first expansion valve is provided on the branch where the first heat exchange unit is located, and a second expansion valve is provided on the branch where the second heat exchange unit is located, and both the first expansion valve and the second expansion valve can realize the functions of adjustable opening and complete cutoff; The thermal management control method further comprises: Acquiring a current superheat degree of the refrigerant at a refrigerant outlet of the second heat exchange unit; The opening degree of the second expansion valve is controlled according to the current superheat and the target superheat.

8. The thermal management control method according to any one of claims 2 to 7, wherein: The first temperature control model at least includes a first temperature difference interval, a second temperature difference interval, a third temperature difference interval, a first target cooling capacity corresponding to the first temperature difference interval, a second target cooling capacity corresponding to the second temperature difference interval, and a third target cooling capacity corresponding to the third temperature difference interval; The upper boundary value of the first temperature difference interval is equal to the lower boundary value of the second temperature difference interval, the upper boundary value of the second temperature difference interval is equal to the lower boundary value of the third temperature difference interval, the first target cooling capacity is less than the second target cooling capacity, and the second target cooling capacity is less than the third target cooling capacity.

9. The thermal management control method according to claim 8, wherein: The second temperature control model at least includes the first temperature difference interval, the second temperature difference interval, the third temperature difference interval, a fourth target cooling capacity corresponding to the first temperature difference interval, a fifth target cooling capacity corresponding to the second temperature difference interval, and a sixth target cooling capacity corresponding to the third temperature difference interval; The fourth target cooling capacity is smaller than the fifth target cooling capacity, the fifth target cooling capacity is smaller than the sixth target cooling capacity, the first target cooling capacity is larger than the fourth target cooling capacity, the second target cooling capacity is larger than the fifth target cooling capacity, and the third target cooling capacity is larger than the sixth target cooling capacity.

10. A thermal management control system, comprising a controller and a thermal management system, wherein: The thermal management system comprises: A refrigerant circuit, comprising a compressor, a condenser, a first expansion valve, a second expansion valve, a first heat exchange unit, a second heat exchange unit, a temperature and pressure sensor, and a first temperature sensor, wherein the exhaust end of the compressor is connected to the inlet of the condenser, the first heat exchange unit has a first channel for refrigerant circulation and a second channel for air circulation, the second heat exchange unit has a third channel for refrigerant circulation and a fourth channel for battery coolant circulation, the inlet of the first channel is connected to the inlet of the third channel and then connected to the outlet of the condenser, the outlet of the first channel is connected to the outlet of the third channel and then connected to the suction end of the compressor, the first expansion valve is arranged at the inlet of the first channel, the second expansion valve is arranged at the inlet of the third channel, the temperature and pressure sensor is arranged at the outlet of the third channel, and the first temperature sensor is arranged at the outlet of the second channel; A battery cooling circuit, comprising a heat exchange portion, a power pump and a second temperature sensor, wherein the heat exchange portion is used to contact the battery, the heat exchange portion has an inlet and an outlet for the battery coolant to enter and exit, the inlet of the heat exchange portion is connected to the outlet of the fourth channel, the outlet of the heat exchange portion is connected to the inlet of the power pump, the outlet of the power pump is connected to the inlet of the fourth channel, and the second temperature sensor is arranged at the inlet of the heat exchange portion; The first temperature sensor, the temperature and pressure sensor, the second temperature sensor, the first expansion valve, the second expansion valve and the compressor are all electrically connected to the controller, and the controller is used to execute the thermal management control method as described in any one of claims 1-9.

11. A working machine, comprising a controller, wherein the controller is used to execute the thermal management control method according to any one of claims 1 to 9; Alternatively, the work machine includes the thermal management control system of claim 10.

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