Temperature estimation method and system, and related apparatus and vehicle

Abstract

Provided in the present invention are a temperature estimation method and system, and a related apparatus and a vehicle. The temperature estimation method comprises the following steps: acquiring an initial temperature T0 of a component of an electric drive system, on which temperature estimation needs to be performed, at an initial moment t0; acquiring operating state data of an operating state of the component; on the basis of the operating state data, acquiring from a preset characteristic value table a steady-state temperature Ts and a time constant τ of the component in the operating state; and on the basis of the initial temperature T0, the steady-state temperature Ts and the time constant τ, calculating the temperature Tk of the component at a moment tk by means of a heat transfer equation.

Description

Temperature estimation method, system, related device and vehicle Technical Field

[0001] The present invention relates to the technical field of temperature estimation of a vehicle electric drive system, and in particular to a temperature estimation method, a temperature estimation system, related devices and a vehicle. Background Art

[0002] With the rapid development of new energy vehicle technology, the power density and integration of electric drive systems are increasing, and the heating of key components in these systems is becoming increasingly serious. Furthermore, the cooling systems of electric drive systems are complex, the cooling media are diverse, and the thermal coupling between components is becoming more complex.

[0003] In order to reduce the risk of thermal failure of the electric drive system and improve thermal reliability, the following tasks need to be completed in terms of temperature estimation of the electric drive system: 1. During the design phase of the electric drive system, a system-level thermal model (also known as a temperature estimation model) should be established to accurately, quickly, and comprehensively calculate the temperature, evaluate and optimize the design, and reduce thermal risks; 2. During the actual operation of the vehicle, a lightweight thermal model should be established to estimate the temperatures of multiple key components of the electric drive system in real time, which will serve as an important input for thermal management and safety strategies; 3. An extremely fast thermal model should be established to calculate the big data temperatures of multiple key components of the electric drive system in real time, which will serve as an important input for calculating reliability and lifespan.

[0004] At present, the types of thermal models or temperature estimation models for key components of electric drive systems in the industry mainly include: 1. Finite element thermal model, which is modeled by the finite element method and uses discretized partial differential equations to iteratively calculate the temperature; 2. Thermal network model, which simplifies the electric drive system into several thermal nodes and calculates the equivalent thermal resistance and thermal capacitance parameters between nodes; 3. Thermal neural network model, which uses a large amount of measured temperature data or simulated temperature data to train the transfer function coefficient network, and calculates the specific output temperature through the trained model; 4. Simplified thermal network plus neural network model, that is, a neural network model is trained based on a thermal network with a small number of nodes, and the resistance and capacitance parameters calculated by the neural network model are combined with the node loss parameters of the thermal network model to solve the node temperature matrix to calculate the node temperature.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0006] One aspect of the present invention aims to solve a technical problem of how to reduce the computational complexity of temperature estimation while ensuring the accuracy of temperature estimation of an electric drive system.

[0007] In addition, other aspects of the present invention are also intended to solve or alleviate other technical problems existing in the prior art.

[0008] The present invention provides a temperature estimation method, system, related device and vehicle. Specifically, according to one aspect of the present invention, it provides:

[0009] A method for estimating the temperature of a vehicle electric drive system comprises the following steps:

[0010] Obtaining the initial temperature T0 of the electric drive system components requiring temperature estimation at the initial time t0;

[0011] Obtaining working condition data of the working condition of the component;

[0012] According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and time constant τ;

[0013] According to the initial temperature T0, steady-state temperature T s The time constant τ is calculated by the heat transfer equation for the components at time t k Temperature T k :

[0014] Optionally, according to one embodiment of the present invention, the heat transfer equation is

[0015] Optionally, according to one embodiment of the present invention, the method further includes the following steps:

[0016] Iteratively execute the above steps at different moments in unit time length until the working condition ends;

[0017] The temperatures of the components at different moments are stored, and the maximum value and / or average value thereof are obtained.

[0018] Optionally, according to one embodiment of the present invention, the operating condition data includes the current torque and speed of the motor, and the characteristic value table includes a discrete data table of the steady-state temperature and time constant of the component corresponding to different torques and speeds, or a characteristic curve of the steady-state temperature and time constant of the component changing with torque and speed.

[0019] Optionally, according to one embodiment of the present invention, the characteristic value table is obtained from a steady-state temperature rise curve obtained by simulating a finite element model or a thermal network model of the electric drive system, or the characteristic value table is obtained from a steady-state temperature rise curve obtained by performing a thermal test on the electric drive system with a limited number of temperature measurement points.

[0020] Optionally, according to an embodiment of the present invention, the operating condition data further includes the current battery voltage or battery SOC, and the characteristic value table further includes a first correction coefficient corresponding to different battery voltages or battery SOCs;

[0021] According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and the time constant τ include the following steps:

[0022] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0023] Obtain a corresponding first correction coefficient by looking up a table according to the current battery voltage or battery SOC;

[0024] The obtained steady-state temperature and time constant are corrected by the first correction coefficient to obtain the actual steady-state temperature T of the component in the working condition. s and time constant τ.

[0025] Optionally, according to an embodiment of the present invention, the operating condition data further includes a current coolant temperature, and the characteristic value table further includes a first adjusted temperature rise corresponding to different coolant temperatures;

[0026] According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and the time constant τ include the following steps:

[0027] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0028] According to the current coolant temperature, a corresponding first adjustment temperature rise is obtained by looking up a table;

[0029] The obtained steady-state temperature is corrected by the first adjustment temperature rise to obtain the actual steady-state temperature T of the component in the working condition. s .

[0030] Optionally, according to an embodiment of the present invention, the operating condition data further includes a current coolant flow rate, and the characteristic value table further includes a second correction coefficient corresponding to different coolant flow rates;

[0031] According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and the time constant τ include the following steps:

[0032] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0033] Calculating a corresponding second correction coefficient based on the current coolant flow rate, calculating a temperature difference between a heat exchange surface of a component and the coolant fluid based on the current coolant flow rate and a heat exchange formula, and calculating a second adjusted temperature rise based on the temperature difference;

[0034] The obtained steady-state temperature is corrected by the second adjusted temperature rise to obtain the actual steady-state temperature T of the component in the working condition. s ; The obtained time constant is corrected by the second correction coefficient to obtain the actual time constant τ of the component in the working condition.

[0035] According to another aspect of the present invention, a temperature estimation system for a vehicle electric drive system is provided, comprising:

[0036] An acquisition module, which obtains the initial temperature T0 of the electric drive system component that needs temperature estimation at the initial time t0, and obtains the working condition data of the working condition of the component;

[0037] The calculation module obtains the steady-state temperature T of the component in the working condition from the preset characteristic value table according to the working condition data. s and time constant τ, and according to the initial temperature T0, steady-state temperature T s The time constant τ is calculated by the following heat transfer equation for the components at time t k Temperature T k .

[0038] Optionally, according to an embodiment of another aspect of the present invention, the heat transfer equation is

[0039] Optionally, according to an embodiment of another aspect of the present invention, the calculation module iteratively performs the above steps at different moments in a unit time length until the working condition ends;

[0040] The temperature estimation system further includes an output module, which stores the temperature of the component at different times and obtains the maximum value and / or average value thereof.

[0041] Optionally, according to an embodiment of another aspect of the present invention, the operating condition data includes the current torque and speed of the motor, and the characteristic value table includes a discrete data table of the steady-state temperature and time constant of the component corresponding to different torques and speeds, or a characteristic curve of the steady-state temperature and time constant of the component changing with torque and speed.

[0042] Optionally, according to an embodiment of another aspect of the present invention, the characteristic value table is obtained from a steady-state temperature rise curve obtained by simulating a finite element model or a thermal network model of the electric drive system, or the characteristic value table is obtained from a steady-state temperature rise curve obtained by performing a thermal test on the electric drive system with a limited number of temperature measurement points.

[0043] Optionally, according to an embodiment of another aspect of the present invention, the operating condition data further includes a current battery voltage or battery SOC, and the characteristic value table further includes a first correction coefficient corresponding to different battery voltages or battery SOCs;

[0044] The calculation module obtains the steady-state temperature T of the component in the working condition from the preset characteristic value table according to the working condition data in the following way s and the time constant τ:

[0045] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0046] Obtain a corresponding first correction coefficient by looking up a table according to the current battery voltage or battery SOC;

[0047] The obtained steady-state temperature and time constant are corrected by the first correction coefficient to obtain the actual steady-state temperature T of the component in the working condition. s and time constant τ.

[0048] Optionally, according to an embodiment of another aspect of the present invention, the operating condition data further includes a current coolant temperature, and the characteristic value table further includes a first adjusted temperature rise corresponding to different coolant temperatures;

[0049] The calculation module obtains the steady-state temperature T of the component in the working condition from the preset characteristic value table according to the working condition data in the following way s and the time constant τ:

[0050] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0051] According to the current coolant temperature, a corresponding first adjustment temperature rise is obtained by looking up a table;

[0052] The obtained steady-state temperature is corrected by the first adjustment temperature rise to obtain the actual steady-state temperature T of the component in the working condition. s .

[0053] Optionally, according to an embodiment of another aspect of the present invention, the operating condition data further includes a current coolant flow rate, and the characteristic value table further includes a second correction coefficient corresponding to different coolant flow rates;

[0054] The calculation module obtains the steady-state temperature T of the component in the working condition from the preset characteristic value table according to the working condition data in the following way s and the time constant τ:

[0055] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0056] Calculating a corresponding second correction coefficient based on the current coolant flow rate, calculating a temperature difference between a heat exchange surface of a component and the coolant fluid based on the current coolant flow rate and a heat exchange formula, and calculating a second adjusted temperature rise based on the temperature difference;

[0057] The obtained steady-state temperature is corrected by the second adjusted temperature rise to obtain the actual steady-state temperature T of the component in the working condition. s ; The obtained time constant is corrected by the second correction coefficient to obtain the actual time constant τ of the component in the working condition.

[0058] According to a third aspect of the present invention, the present invention provides a computer-readable storage medium, on which a computer program is stored, wherein the computer program implements the above-mentioned temperature estimation method when executed by a processor.

[0059] According to a fourth aspect of the present invention, the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the temperature estimation method described above when executing the computer program.

[0060] According to a fifth aspect of the present invention, the present invention provides a vehicle, wherein the vehicle includes an electric drive system and the temperature estimation system described above, and the temperature estimation system is used to estimate the temperature of components of the electric drive system under different working conditions.

[0061] The benefits of the present invention include:

[0062] 1. The temperature estimation method and system of the present invention can be flexibly applied to multiple scenarios, including electric drive product development, component temperature assessment, vehicle applications, and big data applications, meeting the computational requirements of each application scenario. The method and system utilize a simple and lightweight calculation method. When operating conditions remain unchanged, only an exponential function needs to be calculated. When operating conditions change, only a two-dimensional table lookup operation is required. Furthermore, the system performs extremely fast calculations, making it suitable for both real-time vehicle temperature calculation and big data temperature calculation scenarios.

[0063] 2. The temperature estimation method and temperature estimation system of the present invention take into account a variety of operating condition data to correct the key constants of temperature estimation (i.e., steady-state temperature and time constant), especially taking into account the impact of battery, coolant temperature and ambient temperature on the temperature of electric drive system components, and more accurately estimate the temperature of key components while taking into account the external temperature influencing factors of the components. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The above and other features of the present invention will become apparent with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present application. In addition, similar numbers in the drawings represent similar components, wherein:

[0065] FIG1 is a schematic flow chart showing a temperature estimation method according to an embodiment of an aspect of the present invention;

[0066] Figure 2 shows the temperature rise curves of some components of the electric drive system under a certain working condition;

[0067] FIG3 shows a module diagram of a temperature estimation system according to an embodiment of another aspect of the present invention. DETAILED DESCRIPTION

[0068] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the entire invention or as a limitation or restriction of the technical solution of the present invention.

[0069] The terms "up," "down," "left," "right," "front," "back," "front," "back," "top," and "bottom" mentioned or potentially mentioned in this specification are defined relative to the configurations shown in the accompanying drawings. These are relative concepts and may vary depending on the location or usage of the device. Therefore, these or other directional terms should not be construed as restrictive. Furthermore, the terms "first," "second," "third," and similar expressions are used solely for descriptive and distinguishing purposes and should not be construed as indicating or implying the relative importance of the corresponding components or the order or sequence of their assembly.

[0070] The electric drive system is a core component of electric vehicles. With the continuous development of new energy vehicles, the layout requirements for vehicle drive systems are becoming increasingly stringent. The electric drive system is composed of components such as a drive motor, a controller, and a transmission. Heat-generating components in the controller generate a significant amount of heat during operation, and the stator and rotor of the motor also generate a significant amount of heat during operation. To ensure the safety and efficiency of the electric drive system, the temperatures of key components in the system are typically estimated both during the design phase and during vehicle operation to monitor these components in real time. This temperature estimation method is often referred to as a thermal model or temperature estimation model for the electric drive system. This thermal model or temperature estimation model is typically targeted at key components of the electric drive system, particularly the motor, including but not limited to the stator, rotor, bearings, power module, gears, power devices, and busbars. Therefore, the temperature estimation method and system of the present invention are applicable not only to one or more of these key components, but also to the entire electric drive system. In other words, thermal models or temperature estimation models for individual components can be combined into a comprehensive thermal model or temperature estimation model for the electric drive system using methods known to those skilled in the art.

[0071] Referring to FIG1 , a flow chart illustrating a temperature estimation method according to an embodiment of one aspect of the present invention is shown. The temperature estimation method calculates the temperature of key components of an electric drive system at a given moment using a heat transfer equation by looking up the steady-state temperature and time constant obtained from a characteristic value table. The method includes the following steps:

[0072] Obtaining the initial temperature T0 of the electric drive system components requiring temperature estimation at the initial time t0;

[0073] Obtain working condition data of components;

[0074] According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and time constant τ;

[0075] According to the initial temperature T0, steady-state temperature T s The time constant τ is calculated by the heat transfer equation for the components at time t k Temperature T k .

[0076] In this embodiment, the heat transfer equation is:

[0077] For a vehicle's electric drive system, all its dynamic operating conditions can be represented as a characteristic value table or characteristic curve diagram. In this characteristic value table or characteristic curve diagram, the horizontal axis is generally the motor speed and the vertical axis is the motor torque. Under certain motor speeds and motor torques, that is, fixed operating conditions, any position or component of the electric drive system has unique temperature change characteristics, but its temperature change characteristics generally follow the law of the steady-state temperature rise curve. Refer to Figure 2, which shows the temperature rise curves of some components of the electric drive system under a certain operating condition. Figure 2 shows the steady-state temperature rise curves of the motor winding and the rotor magnet of the motor under the same operating condition. This temperature rise curve follows the above heat transfer equation For the temperature rise curves of these two components shown in Figure 2, they have the same initial temperature T0, but their steady-state temperature T s1 、T s2 Different from time constants τ1 and τ2. Steady-state temperature T s is the temperature at which the component reaches thermal stability within its operating condition, and the time constant τ is the time it takes for the temperature rise within that condition to reach 63.2% of the steady-state temperature rise. Thus, for a single operating condition, given the initial temperature of the component, the key parameters of its steady-state temperature rise curve—the steady-state temperature and time constant—are sufficient to determine its temperature at any given moment using the heat transfer equation. If the operating conditions change, the steady-state temperature and time constant will also change with them, but within a single operating condition, they remain constant.

[0078] Therefore, in the embodiment of FIG1 , a characteristic value table for steady-state temperature and time constant is pre-stored, and each characteristic value table corresponds to different operating condition data. In other words, the steady-state temperature and time constant have different values ​​for different operating condition data. Operating condition data includes, for example, motor speed and torque, battery voltage and SOC, coolant flow rate and temperature, and ambient temperature. Motor speed and torque are the primary operating condition data affecting component temperatures, as heat in the electric drive system is primarily generated by motor operation.

[0079] In one embodiment of one aspect of the present invention, the operating condition data includes the current torque and speed of the motor, two primary factors affecting component temperature. The characteristic value table includes the component's steady-state temperature and time constant corresponding to different torques and speeds. In other words, the characteristic value table actually comprises two tables: one is a two-dimensional graph of steady-state temperature versus different torques and speeds, and the other is a two-dimensional graph of time constant versus different torques and speeds. Optionally, the characteristic value table includes a discrete data table showing steady-state temperature and time constant corresponding to different torques and speeds, respectively. The data in the characteristic value table is pre-derived, for example, through calibration testing of the electric drive system or simulation of a thermal model of the electric drive system. During table lookup, the torque and speed from the operating condition data are substituted into the two discrete data tables, and the corresponding steady-state temperature and time constant are calculated using characteristic value fitting. Alternatively, the characteristic value table includes characteristic curves showing how the component's steady-state temperature and time constant vary with torque and speed, respectively. In this case, the characteristic values ​​obtained through calibration testing or simulation are first fitted into a curve. During table lookup, the torque and speed are then directly substituted into the characteristic curve to obtain the corresponding steady-state temperature and time constant values. The steady-state temperature characteristic curve is, for example, a curve family of relationship curves between steady-state temperature and torque at different rotational speeds. The time constant characteristic curve is, for example, a curve family of relationship curves between time constant and rotational speed at different torques.

[0080] In one embodiment of one aspect of the present invention, the characteristic value table is obtained from a steady-state temperature rise curve obtained by simulating a finite element model or a thermal network model of the electric drive system. In this embodiment, it is first necessary to establish a finite element model of the electric drive system or a thermal network model of a key node, and then simulate and calculate the steady-state temperature rise process of all working conditions, extract the steady-state temperature and time constant values ​​from the steady-state temperature rise curve of each working condition, and finally form a characteristic value table. In an optional case, the characteristic value table is obtained from a steady-state temperature rise curve obtained by performing a thermal test of a limited number of temperature measurement points on the electric drive system. In this case, it is necessary to arrange temperature measurement points inside the real electric drive system, measure the steady-state temperature rise process of a limited number of sensors at working points within the continuous capability, and then extract the steady-state temperature and time constant values ​​from the steady-state temperature rise curve of each working condition, and then measure the transient temperature rise process of a limited number of sensors at working points outside the continuous capability, and fit the steady-state temperature and time constant values.

[0081] In one embodiment of one aspect of the present invention, the temperature estimation method further includes the following steps:

[0082] Iteratively executing the steps of the above temperature estimation method at different moments in a unit time length until the working condition ends;

[0083] The temperatures of the components at different moments are stored, and the maximum value and / or average value thereof are obtained.

[0084] It should be understood that the steps in FIG1 are, for example, only the temperature estimation process of a single component at a certain moment in a single operating condition. If you want to continue estimating the temperature of the component in this operating condition, especially to continuously monitor the temperature of the component over a period of time, you can iteratively perform the steps in FIG1, especially the last step. When the operating condition does not change, the steady-state temperature and time constant of the component do not change. At this time, for example, to calculate t k+1 Temperature at time T k+1 The following formula can be used:

[0085] That is to say, the initial temperature of the component is updated to the T k , the time interval also starts from t k -t0 is updated to t k+1 -t k , for the next moment t under the same working condition k+2 For example, the initial temperature and time interval can be updated continuously (updated to T k+1 and t k+2 -t k+1 ), and thus find the next moment t k+2 This calculation can be performed iteratively to obtain and store the temperature at each time interval. Optionally, after obtaining the temperature values ​​of a single component at multiple times, operations such as maximum and average values ​​can be calculated, which facilitates further evaluation of the component's extreme operating conditions and average operating conditions under this operating condition.

[0086] It should be understood that if at a certain moment, for example, moment t i When the working condition changes, the working condition data should be acquired again and the table should be re-checked to obtain the new steady-state temperature T s ' and time constant τ', so at this time, at least the last three steps in Figure 1 should be iterated. After obtaining the new steady-state temperature and time constant, update them to the heat transfer equation. At this time, the initial temperature is still taken from the previous moment t as in the single working condition. i-1 Temperature T i-1 , then the heat transfer equation can be expressed as:

[0087] In the above-mentioned manner, a simple and fast calculation of the temperature of the electric drive system components can be achieved. When the working conditions of the components remain unchanged, only an exponential function needs to be calculated, and when the working conditions change, only a two-dimensional table lookup operation needs to be added, which has a small amount of calculation and an extremely fast calculation speed. The essence of the temperature estimation method of the present invention is to achieve the temperature reduction of the electric drive system in the form of an eigenvalue table, and put the eigenvalue table calculation work before modeling, which greatly simplifies the thermal model of the electric drive system. By simply adjusting the data density and calibration density of the eigenvalue table, the accuracy of the thermal model can be further improved, so that the thermal model can be applied to different usage scenarios and working conditions.

[0088] While the primary factors affecting the temperature of key components in electric drive systems are motor torque and speed, other factors such as battery voltage or SOC, coolant flow and temperature, and ambient temperature also have a certain impact. The following implementation of one aspect of the present invention also takes these factors into account to more accurately determine component temperatures under specific operating conditions.

[0089] In one embodiment of one aspect of the present invention, the operating condition data further includes a current battery voltage or battery SOC, and the characteristic value table further includes a first correction coefficient corresponding to different battery voltages or battery SOCs;

[0090] According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and the time constant τ include the following steps:

[0091] According to the current torque and speed, the corresponding steady-state temperature and time constant of the component are obtained by looking up the table;

[0092] Obtain a corresponding first correction coefficient by looking up a table according to the current battery voltage or battery SOC;

[0093] The obtained steady-state temperature and time constant are corrected by the first correction coefficient to obtain the actual steady-state temperature T of the component in this working condition. s and time constant τ.

[0094] The core of this implementation is to correct the current steady-state temperature and time constant of a component using a first correction coefficient corresponding to the current battery voltage or battery SOC data. Given the same motor torque and speed, increasing the battery voltage or SOC will result in a corresponding increase in the overall temperature of the component at all times. This means that the actual steady-state temperature and time constant of the component should be greater than those obtained when only considering the motor torque and speed. In this case, the characteristic value table includes a pre-stored first correction coefficient corresponding to the battery voltage or battery SOC, which can, for example, be positively correlated with the battery voltage or battery SOC. After the steady-state temperature and time constant are calculated using the torque and speed, they are multiplied by the first correction coefficient to obtain the corrected actual steady-state temperature and time constant. This calculation of the actual steady-state temperature and time constant takes into account the impact of the battery state on the temperature rise of the electric drive system components.

[0095] In one embodiment of one aspect of the present invention, the operating condition data further includes a current coolant temperature, and the characteristic value table further includes first adjusted temperature rises corresponding to different coolant temperatures;

[0096] According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and the time constant τ include the following steps:

[0097] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0098] According to the current coolant temperature, a corresponding first adjustment temperature rise is obtained by looking up a table;

[0099] The obtained steady-state temperature is corrected by the first adjustment temperature rise to obtain the actual steady-state temperature T of the component in this working condition. s .

[0100] In this embodiment, the steady-state temperature is adjusted by taking into account the temperature of the coolant in the cooling system of the electric drive system. The temperature of the coolant directly affects the temperature of the components of the electric drive system. When the coolant temperature increases, the temperature of the components also increases accordingly. When the coolant temperature decreases, the temperature of the components also decreases. Therefore, the steady-state temperature of the components is also positively correlated with the temperature of the coolant. Therefore, the relationship between the steady-state temperature and the coolant temperature can be obtained through calibration experiments. For example, the effect of the coolant temperature on the steady-state temperature change is obtained as the first adjustment temperature rise. When the first adjustment temperature rise is positive, the steady-state temperature should increase, and when it is negative, the steady-state temperature should decrease. In this way, the effect of the coolant temperature change on the steady-state temperature of the components can be taken into account.

[0101] In one embodiment of one aspect of the present invention, the operating condition data further includes a current coolant flow rate, and the characteristic value table further includes a second correction coefficient corresponding to different coolant flow rates;

[0102] According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and the time constant τ include the following steps:

[0103] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0104] Calculating a corresponding first correction coefficient based on the current coolant flow rate, calculating a temperature difference between a heat exchange surface of a component and the coolant fluid based on the current coolant flow rate and a heat exchange formula, and calculating a second adjusted temperature rise based on the temperature difference;

[0105] The obtained steady-state temperature is corrected by the second adjustment temperature rise to obtain the actual steady-state temperature T of the component in this working condition. s ; The obtained time constant is corrected by the second correction coefficient to obtain the actual time constant τ of the component in this working condition.

[0106] The coolant flow rate not only affects the steady-state temperature of the component in its current operating condition, but also the time constant. Generally, the greater the coolant flow rate, the more heat the coolant can absorb, the lower the steady-state temperature of the component, and the smaller the time constant. When determining the effect of the coolant flow rate on the steady-state temperature, the temperature difference between the component's heat exchange surface and the coolant fluid can be directly calculated using the coolant flow rate and heat exchange formula, thereby obtaining the component's second adjusted temperature rise based on this temperature difference. In general, the second adjusted temperature rise is equal to this temperature difference. Adding this temperature difference to the calculated steady-state temperature yields the component's actual steady-state temperature in that operating condition. However, when determining the effect of the coolant flow rate on the time constant, it is still necessary to pre-determine a second correction coefficient for the coolant flow rate to the time constant through calibration experiments. The second correction coefficient is, for example, particularly negatively correlated with the coolant flow rate. In this embodiment, the actual time constant is obtained by multiplying the second correction coefficient by the time constant.

[0107] In one embodiment of one aspect of the present invention, the effect of ambient temperature on the steady-state temperature and time constant of a component is also taken into account. Obviously, the higher the ambient temperature, the higher the steady-state temperature of the component and the larger its time constant, and vice versa. Therefore, a third correction factor corresponding to different ambient temperatures may be pre-stored in the characteristic value table to correct the steady-state temperature and time constant after they are determined solely by looking up the table using torque and speed. This third correction factor, for example, is positively correlated with the ambient temperature and is specifically multiplied by the steady-state temperature and time constant to obtain the actual steady-state temperature and time constant.

[0108] The temperature estimation method of the present invention can be flexibly applied in multiple usage scenarios, including but not limited to the following scenarios:

[0109] (1) Electric drive product development: including product performance, energy consumption calculation optimization, and reliability operating condition design optimization. The thermal model using the characteristic value table can quickly generate electric drive performance curves under different cooling conditions, and the calculation time for CLTC temperature and energy consumption under 216 different cooling conditions is less than 10 seconds;

[0110] (2) Component temperature assessment: Quickly calculate the capacity curve of specific components of the electric drive system, identify the electric drive bottleneck, and identify the risk of component overheating;

[0111] (3) Vehicle application: Replace temperature sensors to perform real-time temperature calculations to implement thermal protection strategies, thermal management strategies, and torque correction strategies;

[0112] (4) Big data application: As a thermal model module of the big data platform, it can input vehicle operation data in batches and output the temperature data of electric drive system components in real time for real-time damage calculation, life calculation, etc.

[0113] Another aspect of the present invention provides a temperature estimation system 100 for a vehicle electric drive system. Referring to FIG3 , a temperature estimation system 100 according to an embodiment of another aspect of the present invention is shown, comprising:

[0114] Acquisition module 1, which acquires the initial temperature T0 of the electric drive system component that needs temperature estimation at the initial time t0, and acquires the working condition data of the working condition of the component;

[0115] Calculation module 2, which obtains the steady-state temperature T of the component in the working condition from the preset characteristic value table according to the working condition data s and time constant τ, and according to the initial temperature T0, steady-state temperature T s The time constant τ is calculated by the heat transfer equation for the components at time t k Temperature T k .

[0116] In one embodiment of another aspect of the present invention, the heat transfer equation is

[0117] In an embodiment of another aspect of the present invention, the calculation module 2 iteratively performs the above steps at different moments in a unit time length until the working condition ends;

[0118] The temperature estimation system 100 further includes an output module, which stores the temperature of the component at different times and obtains the maximum value and / or average value thereof.

[0119] In one embodiment of another aspect of the present invention, the operating condition data includes the current torque and speed of the motor, and the characteristic value table includes a discrete data table of the steady-state temperature and time constant of the component corresponding to different torques and speeds, or a characteristic curve of the steady-state temperature and time constant of the component changing with torque and speed.

[0120] In one embodiment of another aspect of the present invention, the characteristic value table is obtained from a steady-state temperature rise curve obtained by simulating a finite element model or a thermal network model of the electric drive system, or the characteristic value table is obtained from a steady-state temperature rise curve obtained by performing a thermal test on the electric drive system at a limited number of temperature measurement points.

[0121] In an embodiment of another aspect of the present invention, the operating condition data further includes a current battery voltage or battery SOC, and the characteristic value table further includes a first correction coefficient corresponding to different battery voltages or battery SOCs;

[0122] The calculation module 2 obtains the steady-state temperature T of the component in the working condition from the preset characteristic value table according to the working condition data in the following way s and the time constant τ:

[0123] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0124] Obtain a corresponding first correction coefficient by looking up a table according to the current battery voltage or battery SOC;

[0125] The obtained steady-state temperature and time constant are corrected by the first correction coefficient to obtain the actual steady-state temperature T of the component in the working condition. s and time constant τ.

[0126] In an embodiment of another aspect of the present invention, the operating condition data further includes a current coolant temperature, and the characteristic value table further includes first adjusted temperature rises corresponding to different coolant temperatures;

[0127] The calculation module 2 obtains the steady-state temperature T of the component in the working condition from the preset characteristic value table according to the working condition data in the following way s and the time constant τ:

[0128] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0129] According to the current coolant temperature, a corresponding first adjustment temperature rise is obtained by looking up a table;

[0130] The obtained steady-state temperature is corrected by the first adjustment temperature rise to obtain the actual steady-state temperature T of the component in the working condition. s .

[0131] In an embodiment of another aspect of the present invention, the operating condition data further includes a current coolant flow rate, and the characteristic value table further includes a second correction coefficient corresponding to different coolant flow rates;

[0132] The calculation module 2 obtains the steady-state temperature T of the component in the working condition from the preset characteristic value table according to the working condition data in the following way s and the time constant τ:

[0133] Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed;

[0134] Calculating a corresponding second correction coefficient based on the current coolant flow rate, calculating a temperature difference between a heat exchange surface of a component and the coolant fluid based on the current coolant flow rate and a heat exchange formula, and calculating a second adjusted temperature rise based on the temperature difference;

[0135] The obtained steady-state temperature is corrected by the second adjusted temperature rise to obtain the actual steady-state temperature T of the component in the working condition. s ; The obtained time constant is corrected by the second correction coefficient to obtain the actual time constant τ of the component in the working condition.

[0136] It is understandable that the temperature estimation system of the present invention has all the technical effects of the aforementioned temperature estimation method, which will not be described in detail here.

[0137] In the description of the present invention, control modules such as "acquisition module" and "computing module" may include hardware, software or a combination of the two. A module may include hardware circuits, various suitable sensors, communication ports, and memories, and may also include software components such as program codes, or may be a combination of software and hardware. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor, or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, hardware, or a combination of the two. Non-transitory computer-readable storage media include any suitable media that can store program codes, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random access memory, and the like.

[0138] Furthermore, it should be understood that since the setting of the control module is only for illustrating the functional units in the system corresponding to the temperature estimation method of the present invention, the physical device corresponding to the control module can be the processor itself, or a part of the software in the processor, a part of the hardware, or a part of the combination of software and hardware. Therefore, the number of control modules is one for illustration only. It will be understood by those skilled in the art that the control module can be adaptively split according to actual conditions. The specific splitting form of the control module will not cause the technical solution to deviate from the principle of the present invention. Therefore, the technical solutions after splitting will fall within the scope of protection of the present invention.

[0139] A third aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, wherein the computer program implements the above-mentioned temperature estimation method when executed by a processor.

[0140] It can be understood that the computer-readable storage medium has all the technical effects of the aforementioned temperature estimation method, which will not be described in detail here.

[0141] A fourth aspect of the present invention provides a computer device, comprising a memory and a processor, wherein the memory is adapted to store a plurality of program codes, and the program codes are adapted to be loaded and run by the processor to execute the aforementioned temperature estimation method.

[0142] It is understood that the computer device has all the technical effects of the aforementioned temperature estimation method, which will not be described in detail herein. The computer device may include a control device formed by various electronic devices.

[0143] Those skilled in the art will appreciate that all or part of the processes in the temperature estimation method of the present invention can be implemented by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of each of the above-described method embodiments. The computer program includes computer program code. It is understood that the program code includes, but is not limited to, program code for executing the above-described temperature estimation method. For ease of illustration, only the portions relevant to the present invention are shown. The computer program code can be in source code form, object code form, executable file, or some intermediate form. The computer-readable storage medium can include: any entity or device, medium, USB flash drive, removable hard drive, magnetic disk, optical disk, computer memory, read-only memory, random access memory, electric carrier signal, telecommunication signal, and software distribution medium capable of carrying the computer program code. It should be noted that the content of the computer-readable storage medium can be appropriately increased or decreased based on the requirements of legislation and patent practice within a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media do not include electric carrier signals and telecommunication signals.

[0144] A fifth aspect of the present invention provides a vehicle comprising an electric drive system and the aforementioned temperature estimation system, wherein the temperature estimation system is configured to estimate the temperature of components of the electric drive system under different operating conditions. It will be appreciated that this vehicle possesses all the technical advantages of the aforementioned temperature estimation method and will not be further elaborated upon herein.

[0145] It should be understood that the temperature estimation system of the present invention can be installed in various vehicles, including cars, trucks, buses, hybrid vehicles, pure electric vehicles, etc. Therefore, the subject matter of the present invention is also intended to protect various vehicles equipped with the temperature estimation system of the present invention.

[0146] It should be understood that all the above preferred embodiments are illustrative rather than restrictive, and that various modifications or variations made by those skilled in the art to the above-described specific embodiments under the concept of the present invention should be within the legal protection scope of the present invention.

[0147] The relevant user personal information that may be involved in the various embodiments of this application is strictly in accordance with the requirements of laws and regulations, following the principles of legality, legitimacy and necessity, and based on the reasonable purposes of business scenarios, to process the personal information that users actively provide during the use of products / services or generated due to the use of products / services, as well as the personal information obtained with the user's authorization.

[0148] The personal information processed by the Applicant will vary depending on the specific product / service scenario and will be based on the specific scenario in which the user uses the product / service. This may involve the user's account information, device information, driving information, vehicle information, or other related information. The Applicant will treat the user's personal information and its processing with a high degree of diligence.

[0149] The Applicant attaches great importance to the security of user personal information and has taken reasonable and feasible security measures that comply with industry standards to protect user information and prevent personal information from being accessed, disclosed, used, modified, damaged or lost without authorization.

Claims

1. A temperature estimation method for a vehicle electric drive system, characterized in that: The steps include: Obtaining the initial temperature T0 of the electric drive system components that require temperature estimation at the initial time t0; Obtaining working condition data of the working condition of the component; According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and time constant τ; According to the initial temperature T0, steady-state temperature T s The time constant τ is calculated by the heat transfer equation for the components at time t k Temperature T k .

2. The temperature estimation method according to claim 1, characterized in that: The heat transfer equation is 3. The temperature estimation method according to claim 1, characterized in that: The following steps are also included: Iteratively execute the above steps at different moments in unit time length until the working condition ends; The temperatures of the components at different times are stored, and the maximum value and / or average value thereof are obtained.

4. The temperature estimation method according to claim 1, characterized in that: The operating condition data includes the current torque and speed of the motor, and the characteristic value table includes a discrete data table of the steady-state temperature and time constant of the component corresponding to different torques and speeds or a characteristic curve of the steady-state temperature and time constant of the component changing with torque and speed.

5. The temperature estimation method according to claim 4, characterized in that: The characteristic value table is obtained from a steady-state temperature rise curve obtained by simulating a finite element model or a thermal network model of the electric drive system, or the characteristic value table is obtained from a steady-state temperature rise curve obtained by performing a thermal test on the electric drive system at a limited number of temperature measurement points.

6. The temperature estimation method according to claim 4, characterized in that: The operating condition data also includes the current battery voltage or battery SOC, and the characteristic value table also includes a first correction coefficient corresponding to different battery voltages or battery SOCs; According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and time constant τ include the following steps: Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed; Obtain a corresponding first correction coefficient by looking up a table according to the current battery voltage or battery SOC; The obtained steady-state temperature and time constant are corrected by the first correction coefficient to obtain the actual steady-state temperature T of the component in the working condition. s and time constant τ.

7. The temperature estimation method according to claim 4, characterized in that: The operating condition data also includes the current coolant temperature, and the characteristic value table also includes the first adjusted temperature rise corresponding to different coolant temperatures; According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and time constant τ include the following steps: Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed; According to the current coolant temperature, a table is looked up to obtain a corresponding first adjustment temperature rise; The obtained steady-state temperature is corrected by the first adjusted temperature rise to obtain the actual steady-state temperature T of the component in the working condition. s .

8. The temperature estimation method according to claim 4, characterized in that: The operating condition data also includes the current coolant flow rate, and the characteristic value table also includes a second correction coefficient corresponding to different coolant flow rates; According to the working condition data, the steady-state temperature T of the component in the working condition is obtained from the preset characteristic value table. s and time constant τ include the following steps: Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed; Obtaining a corresponding second correction coefficient according to the current coolant flow rate, obtaining a temperature difference between a heat exchange surface of a component and the coolant fluid according to the current coolant flow rate and a heat exchange formula, and obtaining a second adjusted temperature rise according to the temperature difference; The obtained steady-state temperature is corrected by the second adjusted temperature rise to obtain the actual steady-state temperature T of the component in the working condition. s ; The obtained time constant is corrected by using the second correction coefficient to obtain the actual time constant τ of the component in the working condition.

9. A temperature estimation system for a vehicle electric drive system, characterized in that: include An acquisition module, which acquires the initial temperature T0 of the electric drive system component that needs temperature estimation at the initial time t0, and acquires the working condition data of the working condition of the component; A calculation module is used to obtain the steady-state temperature T of the component in the working condition from a preset characteristic value table according to the working condition data. s and time constant τ, and according to the initial temperature T0, steady-state temperature T s The time constant τ is calculated by the heat transfer equation for the components at time t k Temperature T k .

10. The temperature estimation system according to claim 9, characterized in that: The heat transfer equation is 11. The temperature estimation system according to claim 9, characterized in that: The calculation module iteratively executes the above steps at different moments in a unit time length until the working condition ends; The temperature estimation system further comprises an output module, which stores the temperature of the component at different times and obtains the maximum value and / or average value thereof.

12. The temperature estimation system according to claim 9, characterized in that: The operating condition data includes the current torque and speed of the motor, and the characteristic value table includes a discrete data table of the steady-state temperature and time constant of the component corresponding to different torques and speeds or a characteristic curve of the steady-state temperature and time constant of the component changing with torque and speed.

13. The temperature estimation system according to claim 12, characterized in that: The characteristic value table is obtained from a steady-state temperature rise curve obtained by simulating a finite element model or a thermal network model of the electric drive system, or the characteristic value table is obtained from a steady-state temperature rise curve obtained by performing a thermal test on the electric drive system at a limited number of temperature measurement points.

14. The temperature estimation system according to claim 12, characterized in that: The operating condition data also includes the current battery voltage or battery SOC, and the characteristic value table also includes a first correction coefficient corresponding to different battery voltages or battery SOCs; The calculation module obtains the steady-state temperature T of the component in the working condition from the preset characteristic value table according to the working condition data in the following manner: s and the time constant τ: Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed; Obtain a corresponding first correction coefficient by looking up a table according to the current battery voltage or battery SOC; The obtained steady-state temperature and time constant are corrected by the first correction coefficient to obtain the actual steady-state temperature T of the component in the working condition. s and time constant τ.

15. The temperature estimation method according to claim 12, characterized in that: The operating condition data also includes the current coolant temperature, and the characteristic value table also includes the first adjusted temperature rise corresponding to different coolant temperatures; The calculation module obtains the steady-state temperature T of the component in the working condition from a preset characteristic value table according to the working condition data in the following manner: s and the time constant τ: Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed; According to the current coolant temperature, a table is looked up to obtain a corresponding first adjustment temperature rise; The obtained steady-state temperature is corrected by the first adjusted temperature rise to obtain the actual steady-state temperature T of the component in the working condition. s .

16. The temperature estimation method according to claim 12, characterized in that: The operating condition data also includes the current coolant flow rate, and the characteristic value table also includes a second correction coefficient corresponding to different coolant flow rates; The calculation module obtains the steady-state temperature T of the component in the working condition from the preset characteristic value table according to the working condition data in the following manner: s and the time constant τ: Obtaining the corresponding steady-state temperature and time constant of the component by looking up a table according to the current torque and speed; Obtaining a corresponding second correction coefficient according to the current coolant flow rate, obtaining a temperature difference between a heat exchange surface of a component and the coolant fluid according to the current coolant flow rate and a heat exchange formula, and obtaining a second adjusted temperature rise according to the temperature difference; The obtained steady-state temperature is corrected by the second adjusted temperature rise to obtain the actual steady-state temperature T of the component in the working condition. s ; The obtained time constant is corrected by using the second correction coefficient to obtain the actual time constant τ of the component in the working condition.

17. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the temperature estimation method according to any one of claims 1 to 8 is implemented.

18. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the temperature estimation method according to any one of claims 1 to 8 is implemented.

19. A vehicle, characterized in that: The vehicle comprises an electric drive system and a temperature estimation system according to any one of claims 9 to 16, wherein the temperature estimation system is used to estimate the temperature of components of the electric drive system in different operating conditions.

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