DC Support Capacitor Temperature Detection Method, Device, Storage Medium and Equipment

Abstract

The present application provides a method, device, storage medium and equipment for detecting the temperature of a DC support capacitor. In this method, after the vehicle starts, the temperature of the control board and the coolant temperature are obtained, and based on these, the reference temperature of the DC support capacitor is calculated. Then, the ripple current of the DC support capacitor is obtained, the loss of a single cell is calculated, and based on this loss of a single cell, the temperature rise of the DC support capacitor is calculated. Finally, through a target transient model including the step response transfer function of the cell with the highest temperature in the DC support capacitor, combined with the calculated reference temperature and temperature rise, the transient temperature of the DC support capacitor is accurately estimated. In this way, without increasing the cost of the controller, the temperature detection of the DC support capacitor can be realized, which is beneficial to the cost reduction strategy.

Description

Technical Field

[0001] This application relates to the technical field of electric vehicle drive, and more particularly, to a method, device, storage medium, and equipment for detecting the temperature of a DC support capacitor. Background Art

[0002] The DC support capacitor, also known as the bus support capacitor or DC-Link capacitor, is an important component in the electric drive system. During the operation of the electric drive system, in order to prevent the DC support capacitor from being damaged due to overheating, which may lead to the damage of the controller power module, it is necessary to detect the temperature of the DC support capacitor core and implement corresponding protection strategies. In related technologies, generally, a bus support capacitor with a large redundancy or a negative temperature coefficient (NTC) thermistor with a reduced redundancy is used to monitor the temperature of the capacitor core. However, such a method will increase the cost of the controller and is not conducive to cost reduction strategies. Summary of the Invention

[0003] The purpose of this application is to provide a method, device, storage medium, and equipment for detecting the temperature of a DC support capacitor, aiming to solve the problem in related technologies that the temperature detection method for DC support capacitors requires an increase in the cost of the controller and is not conducive to cost reduction strategies.

[0004] In a first aspect, a method for detecting the temperature of a DC support capacitor provided by this application includes: after the vehicle starts, obtaining the control board temperature and the coolant temperature, and determining the reference temperature of the DC support capacitor based on the control board temperature and the coolant temperature; calculating the loss of a single cell of the DC support capacitor based on the ripple current of the DC support capacitor, and calculating the temperature rise of the DC support capacitor based on the loss of the single cell; inputting the reference temperature and the temperature rise into a target transient model to obtain the transient temperature of the DC support capacitor; the target transient model includes the step response transfer function of the highest temperature cell in the DC support capacitor.

[0005] In the above implementation process, after the vehicle starts, the control board temperature and the coolant temperature are obtained to calculate the reference temperature of the DC support capacitor. Then, the ripple current of the DC support capacitor is obtained to calculate the loss of a single cell, and based on the loss of the single cell, the temperature rise of the DC support capacitor is calculated. Finally, through the target transient model including the step response transfer function of the highest temperature cell in the DC support capacitor, combined with the calculated reference temperature and temperature rise, the transient temperature of the DC support capacitor is accurately estimated. In this way, the temperature detection of the DC support capacitor can be realized without increasing the cost of the controller, which is conducive to cost reduction strategies.

[0006] Further, in some examples, determining the reference temperature of the DC support capacitor based on the control board temperature and the coolant temperature includes: determining the ambient temperature according to the control board temperature, the coolant temperature, a first influence ratio, and a second influence ratio; the first influence ratio is the influence ratio of the ambient temperature on the control board temperature; the second influence ratio is the influence ratio of the coolant temperature on the control board temperature; determining the reference temperature of the DC support capacitor according to the ambient temperature, the coolant temperature, a third influence ratio, and a fourth influence ratio; the third influence ratio is the influence ratio of the ambient temperature on the reference temperature; the fourth influence ratio is the influence ratio of the coolant temperature on the reference temperature.

[0007] In the above implementation process, after obtaining the coolant temperature and the control board temperature, the ambient temperature of the controller is obtained by fitting the influence ratios of the ambient temperature and the coolant temperature on the control board temperature respectively, and then the reference temperature of the DC support capacitor is calculated by combining the influence ratios of the ambient temperature and the coolant temperature on the capacitance reference temperature respectively.

[0008] Further, in some examples, the ripple current of the DC support capacitor is obtained based on the effective value of the phase current output by the power module, the power factor, and the modulation ratio; the power factor and the modulation ratio are obtained based on the DQ-axis current and voltage.

[0009] In the above implementation process, a specific method for obtaining the ripple current of the DC support capacitor is provided.

[0010] Further, in some examples, calculating the loss of a single cell of the DC support capacitor based on the ripple current of the DC support capacitor includes: multiplying the square of the ripple current of the DC support capacitor by the equivalent internal resistance of a single cell to obtain the total loss; determining the ratio of the total loss to the number of parallel cells of the DC support capacitor as the loss of a single cell of the DC support capacitor.

[0011] In the above implementation process, a specific method for calculating the loss of a single cell of the DC support capacitor is provided.

[0012] Further, in some examples, calculating the temperature rise of the DC support capacitor according to the loss of a single cell includes: calculating the temperature rise of a single cell according to the loss of a single cell and the thermal resistance of a single cell; taking one of the cells of the DC support capacitor as the main cell, calculating the first radiative temperature rise according to the loss of the remaining cells and the radiative thermal resistance of the remaining cells to the main cell, and calculating the second radiative temperature rise according to the loss of the copper busbar and the radiative thermal resistance of the copper busbar to the main cell; adding the temperature rise of a single cell, the first radiative temperature rise, and the second radiative temperature rise to obtain the temperature rise of the DC support capacitor.

[0013] In the above implementation process, one of the battery cells of the DC support capacitor is taken as the main battery cell, and the temperature rise of the DC support capacitor is divided into three parts: the temperature rise of the main battery cell itself, the thermal radiation temperature rise of the remaining battery cells to the main battery cell, and the thermal radiation temperature rise of the copper bar to the main battery cell. After obtaining the losses and thermal resistances corresponding to the three parts, through the temperature rise calculation formula, the temperature rises corresponding to the three parts are obtained, and then added together to obtain the temperature rise of the DC support capacitor.

[0014] Further, in some examples, the step response transfer function is a second-order transfer function; the transient temperature is obtained by multiplying the step response transfer function by the temperature rise and adding the reference temperature.

[0015] In the above implementation process, a second-order transfer function is selected as the transfer function of the target transient model, which reduces the calculation amount while accurately estimating the transient temperature of the DC support capacitor.

[0016] Further, in some examples, the method further includes: if the transient temperature exceeds the first threshold, controlling the motor torque to derate and operate, and then determining whether the transient temperature exceeds the second threshold; the first threshold is less than the second threshold; if the judgment result is yes, controlling the vehicle to enter the limp home state.

[0017] In the above implementation process, the vehicle is reasonably controlled by comparing the calculated transient temperature with the preset threshold, thereby improving the vehicle safety.

[0018] In a second aspect, a DC support capacitor temperature detection device provided by the present application includes: an acquisition module, configured to acquire the control board temperature and the coolant temperature after the vehicle starts, and determine the reference temperature of the DC support capacitor according to the control board temperature and the coolant temperature; a calculation module, configured to calculate the loss of a single battery cell of the DC support capacitor based on the ripple current of the DC support capacitor, and calculate the temperature rise of the DC support capacitor according to the loss of the single battery cell; an input module, configured to input the reference temperature and the temperature rise into a target transient model to obtain the transient temperature of the DC support capacitor; the target transient model includes the step response transfer function of the battery cell with the highest temperature in the DC support capacitor.

[0019] In a third aspect, an electronic device provided by the present application includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the steps of the method according to any one of the first aspect are implemented.

[0020] Fourthly, a computer-readable storage medium provided by the present application stores instructions thereon. When the instructions are run on a computer, the computer is caused to execute the method according to any one of the first aspect.

[0021] Fifthly, a computer program product provided by the present application, when running on a computer, causes the computer to execute the method according to any one of the first aspect.

[0022] Other features and advantages disclosed in the present application will be described in the subsequent specification. Alternatively, some features and advantages can be inferred from the specification or determined without doubt, or can be known by implementing the above technologies disclosed in the present application.

[0023] To make the above objects, features, and advantages of the present application more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, details are described as follows. Description of the Drawings

[0024] To more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is a flowchart of a method for detecting the temperature of a DC support capacitor provided by an embodiment of the present application;

[0026] Figure 2 It is a schematic diagram of the circuit topology of a motor controller provided by an embodiment of the present application;

[0027] Figure 3 It is a schematic diagram of the working process of a bus support capacitor temperature estimation scheme provided by an embodiment of the present application;

[0028] Figure 4 It is a schematic diagram of a temperature rise model of a single cell of a DC-Link capacitor provided by an embodiment of the present application;

[0029] Figure 5 It is a schematic diagram of a simplified temperature rise model of a DC-Link capacitor cell provided by an embodiment of the present application;

[0030] Figure 6 It is a block diagram of a device for detecting the temperature of a DC support capacitor provided by an embodiment of the present application;

[0031] Figure 7 It is a block diagram of the structure of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0032] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

[0033] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present application, the terms "first", "second", etc. are only used for differential description and cannot be construed as indicating or implying relative importance.

[0034] As described in the background art, in the related art, the temperature detection method for the DC support capacitor has the problem of increasing the cost of the controller, which is not conducive to the cost reduction strategy. Based on this, the embodiments of the present application provide a DC support capacitor temperature detection solution to solve the above problems.

[0035] Next, the embodiments of the present application will be introduced:

[0036] As Figure 1 shown, Figure 1 is a flowchart of a DC support capacitor temperature detection method provided by an embodiment of the present application. The method can be applied to a motor control unit (MCU) on an electric vehicle.

[0037] The method includes:

[0038] In step 101, after the vehicle starts, obtain the control board temperature and the coolant temperature, and determine the reference temperature of the DC support capacitor according to the control board temperature and the coolant temperature;

[0039] After the vehicle starts, the electric drive system is in an operating state. At this time, in order to prevent the DC support capacitor from overheating and being damaged, the controller can trigger the temperature detection process of the DC support capacitor. The reference temperature mentioned in this step can be considered as the initial temperature of the DC support capacitor when it is not working, and this reference temperature is calculated according to the control board temperature and the coolant temperature.

[0040] In some embodiments, determining the reference temperature of the DC support capacitor based on the control board temperature and the coolant temperature in this step may include: determining the ambient temperature according to the control board temperature, the coolant temperature, the first influence ratio, and the second influence ratio; the first influence ratio is the influence ratio of the ambient temperature on the control board temperature; the second influence ratio is the influence ratio of the coolant temperature on the control board temperature; determining the reference temperature of the DC support capacitor according to the ambient temperature, the coolant temperature, the third influence ratio, and the fourth influence ratio; the third influence ratio is the influence ratio of the ambient temperature on the reference temperature; the fourth influence ratio is the influence ratio of the coolant temperature on the reference temperature. That is to say, after obtaining the coolant temperature and the control board temperature, the influence ratios of the ambient temperature and the coolant temperature on the control board temperature can be combined to fit the controller ambient temperature, and then the influence ratios of the ambient temperature and the coolant temperature on the capacitor reference temperature can be combined to calculate the reference temperature of the DC support capacitor. For example, the control board temperature can be expressed as:

[0041]

[0042] In the formula, is the control board temperature; is the ambient temperature; is the coolant temperature; is the influence ratio of the ambient temperature on the control board temperature, that is, the first influence ratio; is the influence ratio of the coolant temperature on the control board temperature, that is, the second influence ratio. According to this formula, the ambient temperature can be calculated; correspondingly, the reference temperature of the DC support capacitor can be expressed as:

[0043]

[0044] In the formula, is the reference temperature of the DC support capacitor; is the influence ratio of the ambient temperature on the reference temperature, that is, the third influence ratio; is the influence ratio of the coolant temperature on the reference temperature, that is, the fourth influence ratio. In this way, the reference temperature of the DC support capacitor can be quickly calculated. Among them, the first influence ratio, the second influence ratio, the third influence ratio, and the fourth influence ratio here can be obtained by data fitting during the calibration test.

[0045] In step 102, based on the ripple current of the DC support capacitor, calculate the single cell loss of the DC support capacitor, and calculate the temperature rise of the DC support capacitor according to the single cell loss;

[0046] The ripple current mentioned in this step refers to the alternating current flowing through the DC support capacitor during the operation of the motor controller. In some embodiments, the ripple current can be obtained from the effective value of the phase current output by the power module, the power factor, and the modulation ratio; the power factor and the modulation ratio are obtained based on the DQ-axis current and voltage. As Figure 2 shown, is the current flowing into the power module 21, is the bus current, is the ripple current flowing through the DC support capacitor 22, and thus the vector formula can be listed as , where , contains both the DC component and the AC component, that is, , ; since the DC component in the bus current does not flow through the DC support capacitor, the DC component flowing into the power model is equal to the DC component in the bus current, so can be obtained; then, according to the relationship between the current flowing into the power module and the effective value of the phase current output by the power module, the power factor, and the modulation ratio, the ripple current of the DC support capacitor can be calculated. Specifically, the ripple current can be calculated based on the following formula:

[0047]

[0048] In the formula, is the ripple current; is the effective value of the phase current output by the power module; is the power factor; is the modulation ratio. Of course, in other embodiments, the ripple current of the DC support capacitor can also be calculated by other means.

[0049] The DC support capacitor includes several parallel-connected battery cells. According to the ripple current of the DC support capacitor, the loss of a single battery cell itself can be calculated, and then the temperature rise of the DC support capacitor can be calculated based on this. In some embodiments, calculating the loss of a single battery cell of the DC support capacitor based on the ripple current of the DC support capacitor mentioned in this step may include: multiplying the square of the ripple current of the DC support capacitor by the equivalent internal resistance of a single battery cell to obtain the total loss; determining the ratio of the total loss to the number of parallel-connected battery cells of the DC support capacitor as the loss of a single battery cell of the DC support capacitor. That is to say, the loss of a single battery cell of the DC support capacitor itself can be expressed as:

[0050]

[0051] In the formula, is the loss of a single battery cell itself; is the equivalent internal resistance of a single battery cell; is the number of parallel-connected cells of the DC support capacitor core.

[0052] Further, in some embodiments, calculating the temperature rise of the DC support capacitor according to the loss of a single cell in this step may include: calculating the temperature rise of a single cell according to the loss of a single cell and the thermal resistance of a single cell; taking one of the cells of the DC support capacitor as the main cell, calculating the first radiative temperature rise according to the loss of the remaining cells and the radiative thermal resistance of the remaining cells to the main cell, and calculating the second radiative temperature rise according to the loss of the copper bar and the radiative thermal resistance of the copper bar to the main cell; adding the temperature rise of the single cell, the first radiative temperature rise and the second radiative temperature rise to obtain the temperature rise of the DC support capacitor. That is to say, assuming that the DC support capacitor includes i parallel-connected cells, and taking one of the cells as the main cell, the temperature rise of the DC support capacitor includes three parts: the temperature rise of the main cell itself, the radiative temperature rise of the remaining cells to the main cell, and the radiative temperature rise of the copper bar to the main cell. After obtaining the losses and thermal resistances corresponding to the three parts, through the temperature rise calculation formula, the temperature rises corresponding to the three parts can be obtained, and then added to obtain the temperature rise of the DC support capacitor. Specifically, the temperature rise of the DC support capacitor can be expressed as:

[0053]

[0054] In the formula, is the temperature rise of the DC support capacitor; is the loss of a single cell itself; is the thermal resistance of a single cell itself; is the loss of the remaining cells themselves; is the radiative thermal resistance of the remaining cells to the main cell; is the loss of the copper bar; is the radiative thermal resistance of the copper bar to the main cell. Through this formula, the temperature rise of the DC support capacitor can be quickly calculated.

[0055] In step 103, input the reference temperature and the temperature rise into the target transient model to obtain the transient temperature of the DC support capacitor; the target transient model includes the step response transfer function of the cell with the highest temperature in the DC support capacitor.

[0056] The transient temperature mentioned in this step may refer to the actual temperature of the DC support capacitor at the current moment. This transient temperature is obtained by inputting the reference temperature and temperature rise into the target transient model. Here, the target transient model can be regarded as a mathematical model for calculating the temperature of the DC support capacitor. The target transient model includes the step response transfer function of the highest temperature cell in the DC support capacitor, and this transfer function can be obtained by data fitting. Using this transfer function and the reference temperature and temperature rise obtained in the previous steps, the temperature of the DC support capacitor at the current moment can be calculated.

[0057] In some embodiments, the step response transfer function mentioned in this step is a second-order transfer function; the transient temperature can be obtained by multiplying the step response transfer function by the temperature rise and adding the reference temperature. Since the FFT (Fast Fourier Transform) analysis of the step response has no resonance peak, a second-order transfer function can achieve a good fitting effect. Based on this, the transient temperature of the DC support capacitor can be expressed as:

[0058]

[0059] In the formula, is the transient temperature of the DC support capacitor; , , , , are the constant coefficients of the second-order transfer function; is the Laplace operator. In this way, while accurately estimating the transient temperature of the DC support capacitor, the calculation amount can be reduced.

[0060] Also, in some embodiments, the above method may further include: if the transient temperature exceeds the first threshold, controlling the motor torque to derate and operate, and then determining whether the transient temperature exceeds the second threshold; the first threshold is less than the second threshold; if the determination result is yes, controlling the vehicle to enter the limp home state. That is to say, a first-level temperature threshold, that is, the first threshold, can be set, and a highest temperature threshold, that is, the second threshold, can be set. When calculating the transient temperature of the DC support capacitor, the controller can determine whether the transient temperature exceeds the first-level temperature threshold. If so, the motor torque derates and operates, otherwise it operates normally, and then determines whether the transient temperature exceeds the highest temperature threshold. If so, it is determined that the capacitor temperature is abnormal, and at this time the vehicle enters the limp home state. In this way, the situation where the bus support capacitor is damaged due to overheating, resulting in damage to the controller power module, can be effectively reduced, and the vehicle safety can be improved. Among them, the first threshold and the second threshold can be set according to the requirements of the specific scenario, and this application does not limit this.

[0061] In the embodiment of the present application, after the vehicle is started, the temperature of the control board and the temperature of the coolant are obtained, and based on these, the reference temperature of the DC support capacitor is calculated. Then, the ripple current of the DC support capacitor is obtained, the loss of a single battery cell is calculated, and based on the loss of the single battery cell, the temperature rise of the DC support capacitor is calculated. Finally, through the target transient model including the step response transfer function of the battery cell with the highest temperature in the DC support capacitor, combined with the calculated reference temperature and temperature rise, the transient temperature of the DC support capacitor is accurately estimated. In this way, without increasing the cost of the controller, the temperature detection of the DC support capacitor can be realized, which is beneficial to the cost reduction strategy.

[0062] To illustrate the solution of the present application in more detail, a specific embodiment will be introduced next:

[0063] This embodiment provides a method for estimating the temperature of the bus support capacitor. In the related art, generally, a bus support capacitor with a large selection redundancy or reducing the redundancy and adding an NTC are used to monitor the temperature of the capacitor battery cells. Both of these two solutions increase the cost of the controller, and since the volume of the bus support capacitor increases with the increase of the capacitance value, therefore, selecting a bus support capacitor with a large redundancy will also increase the volume of the controller. Based on this, this embodiment provides a new estimation method to estimate the temperature of the bus support capacitor through the motor controller to solve the above problems.

[0064] The working process of the solution of this embodiment is as Figure 3 shown and includes:

[0065] S301. It is detected that the vehicle is started;

[0066] S302. The temperature of the coolant and the temperature of the control board are obtained, and based on these, the reference temperature of the DC-Link capacitor is calculated ; where, and respectively represent the influence ratios of the ambient temperature and the water temperature on the temperature of the control board; and respectively represent the influence ratios of the ambient temperature and the water temperature on the reference temperature of the capacitor;

[0067] S303. The effective value of the phase current output by the power module and the DQ-axis current voltage are obtained, and based on the DQ-axis current voltage, the power factor and the modulation ratio are obtained, and thus the ripple current of the DC-Link capacitor is calculated;

[0068] S304. Based on the ripple current , the loss ; where, is the equivalent internal resistance of a single cell, is the number of parallel-connected cells of the DC support capacitor;

[0069] After that, according to the self-loss and the self-thermal resistance of a single cell , the temperature rise of a single cell itself is calculated;

[0070] According to the self-loss of the remaining cells and the thermal radiation thermal resistance of the remaining cells to the calculated cell , the thermal radiation temperature rise of the remaining cells in the DC-Link capacitor to the calculated cell is calculated;

[0071] And, according to the copper bar loss and the thermal radiation thermal resistance of the copper bar to the calculated cell , the thermal radiation temperature rise of the copper bar to the DC-Link capacitor cell is calculated;

[0072] Furthermore, the temperature rise of the DC-Link capacitor is calculated;

[0073] S305. Estimate the transient temperature of the DC-Link capacitor through the target transient model. Specifically, as Figure 4 shown, the temperature rise model of a single cell can be composed of the self-loss of the cell and two RC networks. There is heat transfer of multiple cells and copper bars in the DC-Link capacitor. Then, the temperature rise model of each cell in the DC-Link capacitor can be regarded as a multi-input multi-output system. The inputs are the heat generation of the cell loss and the heat transfer of the remaining cells and copper bars to the capacitor. Based on this, the temperature rise model of a single cell can be simplified to Figure 5 the structure shown;

[0074] The step response transfer function of the highest temperature cell of the DC-Link capacitor is obtained by fitting with the ident toolbox in matlab. Since there is no resonance peak in the FFT analysis of the step response, a second-order transfer function is selected, and a better fitting effect can be obtained. Based on this, the transient temperature of the DC-Link capacitor can be expressed as

[0075] S306. Judge whether the transient temperature exceeds the first-level temperature threshold . If yes, execute S307; otherwise, execute S310;

[0076] S307. Control the motor to operate with torque derating, and then execute S308;

[0077] S308. Judge the transient temperature whether it exceeds the maximum temperature threshold , if yes, execute S309, otherwise execute S310;

[0078] S309. Control the vehicle to enter the limp-home state, and then execute S310;

[0079] S310. After waiting for a preset duration, return to S302.

[0080] In the solution of this embodiment, during the process of realizing the temperature detection of the DC support capacitor, there is no need to increase the cost of the controller, nor to increase the volume of the controller, and the detection accuracy is relatively high; moreover, by comparing the calculated transient temperature with the preset threshold, the vehicle is reasonably controlled, ensuring the safety of the vehicle.

[0081] Corresponding to the embodiment of the foregoing method, the present application also provides an embodiment of a DC support capacitor temperature detection device and a terminal to which it is applied:

[0082] As Figure 6 shown, Figure 6 is a block diagram of a DC support capacitor temperature detection device provided by an embodiment of the present application. The device includes:

[0083] An acquisition module 61, configured to, after the vehicle is started, acquire the control board temperature and the coolant temperature, and determine the reference temperature of the DC support capacitor according to the control board temperature and the coolant temperature;

[0084] A calculation module 62, configured to calculate the single-cell loss of the DC support capacitor based on the ripple current of the DC support capacitor, and calculate the temperature rise of the DC support capacitor according to the single-cell loss;

[0085] An input module 63, configured to input the reference temperature and the temperature rise into a target transient model to obtain the transient temperature of the DC support capacitor; the target transient model includes a step response transfer function of the highest temperature cell in the DC support capacitor.

[0086] For the specific implementation process of the functions and roles of each module in the above device, please refer to the implementation process of the corresponding steps in the above method, which will not be elaborated here.

[0087] The present application also provides an electronic device. Please refer to Figure 7 , Figure 7A structural block diagram of an electronic device provided by an embodiment of the present application. The electronic device may include a processor 710, a communication interface 720, a memory 730, and at least one communication bus 740. Among them, the communication bus 740 is used to implement direct connection communication between these components. Among them, the communication interface 720 of the electronic device in the embodiment of the present application is used to communicate signaling or data with other node devices. The processor 710 may be an integrated circuit chip with signal processing capabilities.

[0088] The above-mentioned processor 710 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or the processor 710 may also be any conventional processor, etc.

[0089] The memory 730 may be, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), etc. The memory 730 stores computer-readable instructions. When the computer-readable instructions are executed by the processor 710, the electronic device may execute the above Figure 1 Each step involved in the method embodiment.

[0090] Optionally, the electronic device may further include a storage controller and an input / output unit.

[0091] The memory 730, the storage controller, the processor 710, the peripheral interface, and the input / output unit are directly or indirectly electrically connected to each other to realize data transmission or interaction. For example, these components may be electrically connected to each other through one or more communication buses 740. The processor 710 is used to execute the executable module stored in the memory 730, such as a software function module or a computer program included in the electronic device.

[0092] The input / output unit is used to provide the user with the ability to create tasks and create an optional start period or a preset execution time for the task, so as to realize the interaction between the user and the server. The input / output unit can be, but is not limited to, a mouse, a keyboard, etc.

[0093] It can be understood that Figure 7 The structure shown is only schematic, and the electronic device may also include more or fewer components than those shown Figure 7 in the figure, or have a different configuration from that shown Figure 7 in the figure. Figure 7 Each component shown in the figure can be implemented by hardware, software, or a combination thereof.

[0094] The embodiments of the present application also provide a storage medium, on which instructions are stored. When the instructions are run on a computer, the computer program, when executed by a processor, implements the method described in the method embodiments. To avoid repetition, it will not be elaborated here.

[0095] The present application also provides a computer program product, which, when run on a computer, causes the computer to execute the method described in the method embodiments.

[0096] In several embodiments provided by the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are only illustrative. For example, the flowcharts and block diagrams in the drawings show the possible architectures, functions, and operations of the devices, methods, and computer program products according to multiple embodiments of the present application. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0097] In addition, in each embodiment of the present application, the various functional modules may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0098] When the above-mentioned functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art or a part of this technical solution can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0099] The above are only the embodiments of this application and are not used to limit the protection scope of this application. For those skilled in the art, this application can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included in the protection scope of this application. It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0100] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by this application and should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

[0101] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

Claims

1. A method for detecting the temperature of a DC support capacitor, characterized in that, Including: After the vehicle starts, obtain the control board temperature and the coolant temperature, and determine the reference temperature of the DC support capacitor according to the control board temperature and the coolant temperature; The reference temperature characterizes the initial temperature of the DC support capacitor in the non-operating state; Based on the ripple current of the DC support capacitor, calculate the single cell loss of the DC support capacitor, and calculate the temperature rise of the DC support capacitor according to the single cell loss; Input the reference temperature and the temperature rise into the target transient model to obtain the transient temperature of the DC support capacitor; the target transient model includes the step response transfer function of the highest temperature cell in the DC support capacitor; the transient temperature characterizes the actual temperature of the DC support capacitor at the current moment; the step response transfer function is a second-order transfer function; the transient temperature is obtained by multiplying the step response transfer function by the temperature rise and adding the reference temperature.

2. The method according to claim 1, wherein The determining the reference temperature of the DC support capacitor according to the control board temperature and the coolant temperature includes: Determine the ambient temperature according to the control board temperature, the coolant temperature, the first influence ratio and the second influence ratio; the first influence ratio is the influence ratio of the ambient temperature on the control board temperature; the second influence ratio is the influence ratio of the coolant temperature on the control board temperature; Determine the reference temperature of the DC support capacitor according to the ambient temperature, the coolant temperature, the third influence ratio and the fourth influence ratio; the third influence ratio is the influence ratio of the ambient temperature on the reference temperature; the fourth influence ratio is the influence ratio of the coolant temperature on the reference temperature.

3. The method according to claim 1, characterized in that The ripple current of the DC support capacitor is obtained based on the effective value of the phase current output by the power module, the power factor and the modulation ratio; the power factor and the modulation ratio are obtained based on the DQ-axis current and voltage.

4. The method according to claim 3, characterized in that The calculating the single cell loss of the DC support capacitor based on the ripple current of the DC support capacitor includes: Multiply the square of the ripple current of the DC support capacitor by the equivalent internal resistance of a single cell to obtain the total loss; Determine the ratio of the total loss to the number of parallel cells of the DC support capacitor as the single cell loss of the DC support capacitor.

5. The method according to claim 4, wherein The calculating the temperature rise of the DC support capacitor according to the single cell loss includes: Calculate the single cell temperature rise according to the single cell loss and the single cell thermal resistance; Take one of the cells of the DC support capacitor as the main cell, calculate the first radiative temperature rise according to the loss of the remaining cells and the radiative thermal resistance of the remaining cells to the main cell, and calculate the second radiative temperature rise according to the loss of the copper busbar and the radiative thermal resistance of the copper busbar to the main cell; Add the single cell temperature rise, the first radiative temperature rise and the second radiative temperature rise to obtain the temperature rise of the DC support capacitor.

6. The method according to claim 1, characterized in that, The method further includes: If the transient temperature exceeds the first threshold, control the motor torque to derate and run, and then determine whether the transient temperature exceeds the second threshold; the first threshold is less than the second threshold; If the judgment result is yes, control the vehicle to enter the limp home state.

7. A DC support capacitor temperature detection device, characterized in that, Including: An acquisition module, configured to acquire the control board temperature and the coolant temperature after the vehicle starts, and determine the reference temperature of the DC support capacitor according to the control board temperature and the coolant temperature; The reference temperature characterizes the initial temperature of the DC support capacitor in a non-operating state; A calculation module, configured to calculate the single cell loss of the DC support capacitor based on the ripple current of the DC support capacitor, and calculate the temperature rise of the DC support capacitor according to the single cell loss; An input module, configured to input the reference temperature and the temperature rise into a target transient model to obtain the transient temperature of the DC support capacitor; the target transient model includes the step response transfer function of the highest temperature cell in the DC support capacitor; the transient temperature characterizes the actual temperature of the DC support capacitor at the current moment; the step response transfer function is a second-order transfer function; the transient temperature is obtained by adding the product of the step response transfer function and the temperature rise to the reference temperature.

8. A computer-readable storage medium, characterized in that, A computer program is stored thereon, and when the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

9. An electronic device, characterized in that, It includes a processor, a memory, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

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