Method for calculating core temperature of direct-current support capacitor and related device

Abstract

The application discloses a kind of core cell temperature calculation method of direct current support capacitor and related equipment, belong to wireless communication field, the method includes: obtaining the loss value of direct current support capacitor, while also obtaining the temperature value of cooling medium corresponding to direct current support capacitor, at this time, the thermal impedance value of the hot spot of the core cell of the direct current support capacitor is obtained to obtain the data basis for calculating the temperature value of the branch flow support capacitor, after obtaining the loss value, the temperature value of cooling medium and thermal impedance value, the core cell temperature value of the direct current support capacitor can be calculated, and then the core cell temperature value of the direct current support capacitor is used as the temperature value of the branch flow support capacitor, without the access of external parts, the reliability of branch flow support capacitor can be guaranteed.

Description

Technical Field

[0001] This disclosure relates to the field of automotive electronics technology, specifically to a method and related equipment for calculating the cell temperature of a DC-supported capacitor. Background Technology

[0002] With the gradual development of automotive electronics technology, high-power power converters such as photovoltaics and energy storage play an important role in the application of automotive electronics technology. Among these high-power power converters, important inverters are included, such as DC support capacitors. For DC support capacitors, the main factor affecting their performance is temperature. Excessive temperature can lead to performance degradation or even failure. Therefore, by monitoring the temperature of the DC support capacitor, corresponding measures can be taken to avoid performance degradation due to excessive temperature.

[0003] The temperature of a DC support capacitor is typically measured by its core temperature. Existing technology involves adding a thermocouple to the outside of the DC support capacitor to directly measure its core temperature. However, since thermocouples are non-standard products, they can only be used during the verification phase. Furthermore, adding a thermocouple to the outside of the DC support capacitor can affect its reliability.

[0004] Therefore, the method of directly measuring the temperature of the DC support capacitor by adding a thermocouple has the problem of low reliability. Summary of the Invention

[0005] This application provides a method and related equipment for calculating the cell temperature of a DC support capacitor, which can solve the problem of low reliability in the prior art.

[0006] In a first aspect, embodiments of this application provide a method for calculating the cell temperature of a DC-supported capacitor, the method comprising:

[0007] Obtain the loss value of the DC support capacitor;

[0008] Obtain the temperature value of the cooling medium corresponding to the DC support capacitor;

[0009] Obtain the thermal resistance value from the hot spot of the DC support capacitor cell to the cooling medium;

[0010] The cell temperature of the DC support capacitor is determined based on the loss value, the temperature of the cooling medium, and the thermal impedance value.

[0011] In one possible embodiment, the method for determining the cell temperature of the DC-supported capacitor based on the loss value, the temperature value of the cooling medium, and the thermal impedance value includes:

[0012] The cell temperature of the DC-supported capacitor is determined using the following formula:

[0013] T DC-link =T fluent +P loss *Z th

[0014] Among them, T DC-link T represents the cell temperature value of the DC-supported capacitor. fluent P represents the temperature value of the cooling medium. loss Z is the loss value. th The value is the thermal resistance.

[0015] In one possible embodiment, before obtaining the loss value of the DC support capacitor, the method for calculating the cell temperature of the DC support capacitor further includes:

[0016] Obtain the ripple current value of the DC support capacitor;

[0017] Obtain the equivalent series resistance value of the DC support capacitor;

[0018] The loss value of the DC support capacitor is determined based on the ripple current value and the equivalent series resistance value of the DC support capacitor.

[0019] In one possible embodiment, the method for obtaining the ripple current value of the DC support capacitor and calculating the cell temperature of the DC support capacitor includes:

[0020] The power factor, modulation ratio, and output current of the vehicle inverter are obtained, and the vehicle inverter includes the DC support capacitor.

[0021] The ripple current value of the DC support capacitor is determined based on the power factor, modulation ratio, and output current of the vehicle inverter.

[0022] In one possible implementation, the thermal circuit model of the DC support capacitor includes N series-connected impedance modules, each of which includes a thermal resistor and a thermal capacitor connected in parallel, where N is a positive integer.

[0023] The step of obtaining the thermal resistance value from the hot spot of the DC support capacitor cell to the cooling medium includes:

[0024] For each impedance module, the product of the thermal resistance and thermal capacitance in the impedance module is calculated to obtain the thermal temperature coefficient of the impedance module; the thermal resistance is the resistance value of the thermal resistance in the impedance module, and the thermal capacitance is the capacitance value of one thermal capacitance in the impedance module.

[0025] The thermal resistance value of the impedance module is determined based on the thermal temperature coefficient.

[0026] The sum of the thermal impedance values ​​of the N impedance modules is determined as the thermal impedance value from the hot spot of the DC support capacitor cell to the cooling medium.

[0027] In one possible embodiment, after determining the cell temperature of the DC-supported capacitor based on the loss value, the temperature value of the cooling medium, and the thermal impedance value, the method for calculating the cell temperature of the DC-supported capacitor further includes:

[0028] To ensure that the cell temperature of the DC support capacitor is less than or equal to the preset temperature value, at least two of the following values ​​of the vehicle inverter—power factor, modulation ratio, and output current—are adjusted:

[0029] Secondly, embodiments of this application provide a cell temperature calculation device for a DC-supported capacitor. The cell temperature calculation device for a DC-supported capacitor includes a first acquisition module for acquiring the loss value of the DC-supported capacitor.

[0030] The second acquisition module is used to acquire the temperature value of the cooling medium corresponding to the DC support capacitor;

[0031] The third acquisition module is used to acquire the thermal resistance value from the hot spot of the DC support capacitor cell to the cooling medium.

[0032] The first determining module is used to determine the cell temperature value of the DC support capacitor based on the loss value, the temperature value of the cooling medium, and the thermal impedance value.

[0033] Thirdly, embodiments of this application provide an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the cell temperature calculation method for the aforementioned DC support capacitor.

[0034] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program, characterized in that, when executed by a processor, the computer program implements the various processes of the above-described embodiment for calculating the cell temperature of the DC-supported capacitor.

[0035] Fifthly, embodiments of this application provide a computer program product in which instructions, when executed by a processor of an electronic device, cause the electronic device to perform various processes implementing the above-described embodiment of calculating the cell temperature of the DC-supported capacitor.

[0036] This application provides a method and related equipment for calculating the cell temperature of a DC-supported capacitor. The method obtains the loss value of the DC-supported capacitor and the temperature value of the corresponding cooling medium. Simultaneously, it obtains the thermal resistance value from the hot spot of the DC-supported capacitor cell to the cooling medium, providing the data basis for calculating the temperature value of the DC-supported capacitor. With the loss value, cooling medium temperature value, and thermal resistance value obtained, the cell temperature value of the DC-supported capacitor can be calculated and used as the temperature value of the DC-supported capacitor. Thus, this application embodiment can calculate the cell temperature value of the DC-supported capacitor by obtaining the corresponding data of the DC-supported capacitor, without the need for external components, ensuring the reliability of the DC-supported capacitor. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application are briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a main power topology diagram of the vehicle inverter circuit provided in the embodiments of this application;

[0039] Figure 2 A flowchart illustrating a method for calculating the cell temperature of a DC-supported capacitor, as provided in this application embodiment;

[0040] Figure 3 Thermal simulation cloud diagram of the DC support capacitor provided in the embodiments of this application;

[0041] Figure 4 A circuit diagram of a thermal circuit model provided in an embodiment of this application;

[0042] Figure 5 A temperature rise curve of the core temperature of a DC support capacitor provided in an embodiment of this application;

[0043] Figure 6 A structural block diagram of a method for calculating the cell temperature of a DC-supported capacitor provided in an embodiment of this application;

[0044] Figure 7 This is a structural diagram of a DC-supported capacitor cell temperature calculation electronic device provided in an embodiment of this application. Detailed Implementation

[0045] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0046] In this document, relational terms such as "first," "second," etc., are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0047] With the gradual development of automotive electronics technology, high-power power converters such as photovoltaics and energy storage are playing an important role in the application of automotive electronics technology. Among these high-power power converters, important inverters include, for example, DC-link capacitors.

[0048] In the main power drive of an automotive inverter, such as Figure 1 As shown, the autonomous power circuit mainly consists of a DC support capacitor (101) and a power module. The DC-link is the medium for AC and DC power exchange, which can smooth instantaneous power, improve the electromagnetic compatibility (EMC) of the system, smooth the bus voltage, suppress the ripple amplitude of the bus voltage, absorb the high pulse current at the motor controller bus terminal, provide instantaneous power to the load, avoid transient changes in DC bus voltage, and form the minimum loop for power module turn-on and turn-off. The DC-link plays a crucial role in the entire vehicle inverter, directly affecting the performance of the vehicle inverter and its service life.

[0049] For DC-link, the main factor affecting its performance is temperature. Some literature points out that for every 8°C increase in cell temperature, the lifespan of DC-link is reduced by half. Therefore, excessively high temperature can lead to a decrease in DC-link performance or even failure, which in turn can greatly shorten the lifespan of the vehicle inverter.

[0050] To improve the lifespan of vehicle inverters, the temperature of the DC-link needs to be monitored to take appropriate measures to reduce it. Currently, monitoring the DC-link temperature generally requires the use of external equipment, such as adding thermocouple sensors and external testing equipment to measure the core temperature of the DC-link. The core can be the part of the DC-link with the highest temperature.

[0051] The applicant's research has revealed the following technical problems with the current method of directly measuring the core temperature of a DC-link using thermocouples: Because of the addition of thermocouple sensors and external testing equipment, this method of measuring the core temperature of a DC-link is limited to the R&D stage. For mass-produced products (such as DC-link), adding external thermocouple sensors and external testing equipment to measure temperature will affect the reliability of the DC-link. Therefore, while the method of directly measuring the core temperature of a DC-link using thermocouples can be used during the verification process in the R&D stage, using this method for mass-produced products will affect the reliability of the DC-link.

[0052] In view of the above research findings, this application provides a method for calculating the cell temperature of a DC-supported capacitor to solve the above-mentioned technical problems existing in the prior art.

[0053] The technical concept of this application embodiment lies in: obtaining the loss value of the DC support capacitor, and simultaneously obtaining the temperature value of the cooling medium corresponding to the DC support capacitor. At this time, the thermal resistance value from the hot spot of the DC support capacitor cell to the cooling medium is obtained to provide the data basis for calculating the temperature value of the DC support capacitor. Having obtained the aforementioned loss value, cooling medium temperature value, and thermal resistance value, the cell temperature value of the DC support capacitor can be calculated, and this cell temperature value is then used as the temperature value of the DC support capacitor. Thus, this application embodiment can obtain the corresponding data of the DC support capacitor, calculate the cell temperature value of the DC support capacitor, and then use the cell temperature value of the DC support capacitor as the temperature value of the DC support capacitor, without the need for external components, ensuring the reliability of the DC support capacitor.

[0054] This embodiment provides a method for calculating the cell temperature of a DC-supported capacitor, such as... Figure 2 As shown, the steps are as follows:

[0055] S201: Obtain the loss value of the DC support capacitor.

[0056] The energy consumed by a DC-link due to heat generation per unit time under the influence of an electric field can be called loss. The loss of a DC-link can include dielectric loss, conductivity loss, and loss caused by the resistance of all metal parts of the capacitor.

[0057] The losses of a DC-link vary under different operating conditions.

[0058] Under the influence of a DC electric field, the losses of a DC-link can include leakage conduction loss, which is generally small.

[0059] Under the influence of an alternating electric field, the losses of a DC-link can include leakage conduction losses. At the same time, there will also be some losses in the DC-link during the periodic polarization establishment process.

[0060] The loss of the DC-link can be, but is not limited to, calculated by the user using a formula. In addition, obtaining the loss value of the DC-link can serve as the basis for calculating the cell temperature value of the DC support capacitor.

[0061] S202: Obtain the temperature value of the cooling medium corresponding to the DC support capacitor.

[0062] Cooling media can include, but are not limited to, air, water, and oil. By passing the DC-link through the cooling medium, the rate of temperature rise of the DC-link is reduced, ensuring the reliability of the DC-link and maintaining the operation of the circuit. Thus, it can be determined that a portion of the DC-link's temperature is carried away by the cooling medium to ensure the reliability of the DC-link.

[0063] Obtain the temperature value of the cooling medium corresponding to the DC-link, and determine the temperature value of the DC-link carried away by the cooling medium. This temperature value is the basic data for determining the temperature of the DC-link cell.

[0064] S203: Obtain the thermal resistance value from the hot spot of the DC support capacitor cell to the cooling medium.

[0065] like Figure 3 As shown, the thermal simulation diagram of the DC support capacitor is divided according to color depth, with darker colors indicating higher temperatures of the DC support capacitor.

[0066] By obtaining the thermal resistance value from the hot spot of the DC-link cell to the cooling medium, the temperature value generated due to thermal resistance operation is determined. This temperature value is the basic data for determining the DC-link cell temperature.

[0067] S204: Determine the cell temperature value of the DC support capacitor based on the loss value, the temperature value of the cooling medium, and the thermal resistance value.

[0068] The core temperature of the DC-link support capacitor can be directly measured by a thermocouple. However, this direct measurement method requires connection to an external device, and the operation of the external device will generate heat, which will affect the DC-link core temperature and thus the measurement of the DC-link core temperature, resulting in low reliability.

[0069] Unlike direct measurement methods, the embodiments of this application do not require connection to external devices, and therefore will not affect the temperature of the capacitor core, thereby ensuring the reliability of the DC-link.

[0070] In some embodiments, the known loss value, the temperature value of the cooling medium, and the thermal impedance value can be used to further determine the cell temperature value of the DC support capacitor.

[0071] This application provides a method for calculating the cell temperature of a DC-supported capacitor. The method involves obtaining the loss value of the DC-supported capacitor and the temperature value of the corresponding cooling medium. Simultaneously, the thermal resistance value from the hot spot of the DC-supported capacitor cell to the cooling medium is obtained to provide the data basis for calculating the temperature value of the DC-supported capacitor. With the loss value, cooling medium temperature value, and thermal resistance value obtained, the cell temperature value of the DC-supported capacitor can be calculated and used as the temperature value of the DC-supported capacitor. Thus, this application embodiment can obtain the corresponding data of the DC-supported capacitor, calculate the cell temperature value of the DC-supported capacitor, and then use the cell temperature value as the temperature value of the DC-supported capacitor, without the need for external components, ensuring the reliability of the DC-supported capacitor.

[0072] In some embodiments, the method for determining the cell temperature of the DC-supported capacitor based on the loss value, the temperature value of the cooling medium, and the thermal impedance value may include:

[0073] The cell temperature of the DC-supported capacitor is determined using the following formula:

[0074] T DC-link =T fluent +P loss *Z th

[0075] Among them, T DC-link T represents the cell temperature value of the DC-supported capacitor. fluent P represents the temperature value of the cooling medium. loss Z is the loss value.th The value is the thermal resistance.

[0076] As can be seen from the formula, the product of the DC-link's loss value and thermal resistance value is calculated, and then the sum of this product and the temperature value of the cooling medium is calculated. This sum of the product and the temperature value of the cooling medium can be expressed as the DC-link's cell temperature value.

[0077] In some embodiments, the factors affecting the cell temperature of the DC-link can be intuitively determined by formulas, namely the temperature, loss, and thermal resistance of the cooling medium. Therefore, the cell temperature of the DC-link can be affected by adjusting the temperature, loss, and thermal resistance of the cooling medium.

[0078] The formula can express the relationship between the cell temperature, cooling medium temperature, loss value and thermal resistance value of the DC support capacitor, and thus the cell temperature of the DC support capacitor can be quickly determined by the formula.

[0079] In some embodiments, before obtaining the loss value of the DC support capacitor, the method for calculating the cell temperature of the DC support capacitor may further include:

[0080] Obtain the ripple current value of the DC support capacitor;

[0081] Obtain the equivalent series resistance value of the DC support capacitor;

[0082] The loss value of the DC support capacitor is determined based on the ripple current value and the equivalent series resistance value of the DC support capacitor.

[0083] Ripple current can include the effective (Root Mean Square, RMS) value of the alternating current flowing through the capacitor, which is expressed as a pulsating or ripple voltage.

[0084] The maximum permissible ripple current of a DC-link capacitor is limited by ambient temperature, capacitor surface temperature (and heat dissipation area), loss angle (or ESR), and AC frequency parameters. It is worth noting that temperature is a decisive factor in capacitor lifespan; therefore, the heat loss caused by ripple becomes a key reference factor for capacitor lifespan.

[0085] Since the capacitor used in a circuit is not an ideal capacitor, it can be approximated as an ideal capacitor connected in series with a resistor. Therefore, this resistor can be defined as the equivalent series resistance (R). ESR ).

[0086] Therefore, in this embodiment of the application, the loss value of the DC-link is calculated based on the ripple current flowing through the DC-link.

[0087] In some embodiments, the temperature loss value of the DC-link is determined using the following formula.

[0088]

[0089] Among them, P loss R is the loss value of the DC support capacitor. esr I is the equivalent series resistance of the DC support capacitor. ripple This is the ripple current value of the DC support capacitor.

[0090] By obtaining the ripple current flowing through the DC-link and the equivalent series resistance of the DC support capacitor, the loss value of the DC support capacitor can be determined, and thus the cell temperature value of the DC support capacitor can be determined.

[0091] In some embodiments, the method for obtaining the ripple current value of the DC support capacitor and calculating the cell temperature of the DC support capacitor may include:

[0092] The power factor, modulation ratio, and output current of the vehicle inverter are obtained, and the vehicle inverter includes the DC support capacitor.

[0093] The ripple current value of the DC support capacitor is determined based on the power factor, modulation ratio, and output current of the vehicle inverter.

[0094] A vehicle-mounted power inverter is a type of power converter that can convert direct current (DC) to alternating current (AC) for use in general electrical appliances.

[0095] Key components in an onboard inverter may include a DC-link, thus the ripple current value of the DC support capacitor can be determined based on the inverter's power factor, modulation ratio, and output current.

[0096] In some embodiments, the ripple current value of the DC support capacitor can be determined using the following formula.

[0097]

[0098] Among them, I o θ is the output current of the vehicle inverter, M is the modulation ratio of the vehicle inverter, and cos(θ) is the power factor of the vehicle inverter.

[0099] In one specific embodiment, the user can configure the output current I of the vehicle inverter. o The ripple current value of the DC support capacitor is calculated based on the following parameters: 280A, modulation ratio M of the vehicle inverter is 0.8, and power factor cos(θ) of the vehicle inverter is 0.9.

[0100] The ripple current value of the DC support capacitor can be determined by the value of the on-board inverter, providing basic data for determining the cell temperature value of the DC support capacitor.

[0101] In some embodiments, the thermal circuit model of the DC support capacitor includes N series-connected impedance modules, each of which includes a thermal resistor and a thermal capacitor connected in parallel, where N is a positive integer.

[0102] The step of obtaining the thermal resistance value from the hot spot of the DC support capacitor to the cooling medium may include:

[0103] For each impedance module, the product of the thermal resistance and thermal capacitance in the impedance module is calculated to obtain the thermal temperature coefficient of the impedance module; the thermal resistance is the resistance value of the thermal resistance in the impedance module, and the thermal capacitance is the capacitance value of one thermal capacitance in the impedance module.

[0104] The thermal resistance value of the impedance module is determined based on the thermal temperature coefficient.

[0105] The sum of the thermal impedance values ​​of the N impedance modules is determined as the thermal impedance value from the hot spot of the DC support capacitor cell to the cooling medium.

[0106] Depend on Figure 4 As shown, the thermal circuit model of the DC supporting capacitor includes N series-connected impedance modules, each of which includes a thermal resistor and a thermal capacitor connected in parallel. Specifically, 410, 420, and 430 represent the first, second, and Nth impedance modules closest to the constant voltage source 440 in the thermal circuit model, respectively, and each of these modules corresponds to a thermal resistor (412, 422, 432) and a thermal capacitor (411, 421, 431).

[0107] The thermal temperature coefficient can be obtained by calculating the product of the thermal resistance and thermal capacity in the impedance module using the following formula.

[0108] τ i =R thi ×C thi

[0109] Where, τ i Let R be the i-th thermal temperature coefficient among N impedance modules. thi Let C be the resistance value of the i-th thermal resistor in N impedance modules. thi Let be the capacitance value of the i-th thermal capacitor among N impedance modules.

[0110] After determining the thermal temperature coefficient, the thermal resistance value from the hot spot of the DC support capacitor cell to the cooling medium can be determined by the following formula.

[0111]

[0112] Among them, Z th t represents the thermal resistance value from the hot spot of the DC-supported capacitor cell to the cooling medium, and t represents time.

[0113] In a specific embodiment, considering the dynamic performance of the system and the computational load of the software, as shown in Table 1, four impedance modules can be selected, and the thermal impedance values ​​corresponding to the four impedance modules can be calculated. Thus, the following formula can be derived. After discretizing the following formula, a program to monitor the core temperature of the DC-link can be written in the software, thereby enabling the real-time calculation of the core temperature of the DC-link and achieving the purpose of real-time calculation of the core temperature of the DC-link.

[0114]

[0115] Among them, T DC-link T represents the cell temperature of the DC-link. fluent P represents the temperature value of the cooling medium. loss The loss value is... The values ​​represent the thermal resistance of the four impedance modules to the beverage.

[0116] Table 1: Schematic diagram of a fourth-order impedance module

[0117] thermal resistance <![CDATA[R th1 ]]> <![CDATA[R th2 ]]> <![CDATA[R th3 ]]> <![CDATA[R th4 ]]> heat capacity <![CDATA[C th1 ]]> <![CDATA[C th2 ]]> <![CDATA[C th3 ]]> <![CDATA[C th4 ]]>

[0118] In a specific embodiment, under conditions of 280A current, 420V voltage, and 10K carrier frequency, the first curve of capacitance change over time can be obtained using the thermal circuit model of this application, as shown below. Figure 5 As shown, it can be Figure 5 The data is input into Matlab. Considering the loss value of the DC support capacitor, the corresponding cell temperature rise curve is fitted. In addition, a simulation experiment can be performed under the same conditions to obtain a second curve of capacitance change over time. The first temperature value can be the value corresponding to the target time point in the first curve, and the second temperature value can be the value corresponding to the target time point in the second curve. The first and second curves are fitted using at least one first temperature value and one second temperature value. At the same time, considering the loss value of the DC support capacitor and taking into account dynamic performance and software computation, N impedance modules are selected.

[0119] The reliability of the thermal circuit model can be improved by training it until the first and second temperature values ​​are fitted.

[0120] In some embodiments, after determining the cell temperature value of the DC-supported capacitor based on the loss value, the temperature value of the cooling medium, and the thermal impedance value, the method for calculating the cell temperature of the DC-supported capacitor may further include:

[0121] To ensure that the cell temperature of the DC support capacitor is less than or equal to the preset temperature value, at least two of the following values ​​of the vehicle inverter—power factor, modulation ratio, and output current—are adjusted:

[0122] The preset temperature value can be set by the user.

[0123] To ensure the reliable operation of the vehicle inverter, at least two of the inverter's power factor, modulation ratio, and output current can be adjusted to reduce the cell temperature of the DC support capacitor without reducing the inverter's output power, until the cell temperature of the DC support capacitor is less than or equal to a preset temperature value.

[0124] If the calculated cell temperature of the DC support capacitor is greater than the preset temperature value, the control strategy of the vehicle inverter will be adjusted in a timely manner without reducing the output power of the vehicle inverter and ensuring its reliable operation. This will reduce the cell temperature of the DC support capacitor to less than or equal to the preset temperature value, thereby reducing the possibility of DC support capacitor performance failure due to excessive temperature.

[0125] In addition, see Figure 6 This application also provides a cell temperature calculation device 400 for a DC-supported capacitor. The device 600 includes a first acquisition module 601, a second acquisition module 602, a third acquisition module 603, and a first determination module 604. These modules work together to complete the cell temperature calculation process for the DC-supported capacitor. Specifically:

[0126] The first acquisition module 601 is used to acquire the loss value of the DC support capacitor;

[0127] The second acquisition module 602 is used to acquire the temperature value of the cooling medium corresponding to the DC support capacitor;

[0128] The third acquisition module 603 is used to acquire the thermal resistance value from the hot spot of the DC support capacitor to the cooling medium.

[0129] The first determining module 604 is used to determine the cell temperature value of the DC support capacitor based on the loss value, the temperature value of the cooling medium, and the thermal impedance value.

[0130] In some embodiments, the first determining module 604 is configured to determine the cell temperature value of the DC-supported capacitor based on the loss value, the temperature value of the cooling medium, and the thermal impedance value. The cell temperature calculation device for the DC-supported capacitor may further include:

[0131] The second determining module is used to determine the cell temperature value of the DC support capacitor using the following formula:

[0132] T DC-link =T fluent +P loss *Z th

[0133] Among them, T DC-link T represents the cell temperature value of the DC-supported capacitor. fluent P represents the temperature value of the cooling medium. loss Z is the loss value. th The thermal resistance value is specified. In some embodiments, the device further includes a determining module.

[0134] In some embodiments, before the first acquisition module 601 acquires the loss value of the DC support capacitor, the apparatus may further include:

[0135] The fourth acquisition module is used to acquire the ripple current value of the DC support capacitor;

[0136] The fifth acquisition module is used to acquire the equivalent series resistance value of the DC support capacitor;

[0137] The third determining module is used to determine the loss value of the DC support capacitor based on the ripple current value and the equivalent series resistance value of the DC support capacitor.

[0138] In some embodiments, the fourth acquisition module is used to acquire the ripple current value of the DC support capacitor, and the device may further include:

[0139] The sixth acquisition module is used to acquire the power factor, modulation ratio and output current of the vehicle inverter, wherein the vehicle inverter includes the DC support capacitor;

[0140] The fourth determining module is used to determine the ripple current value of the DC support capacitor based on the power factor, modulation ratio, and output current of the vehicle inverter.

[0141] In some embodiments, the thermal circuit model of the DC support capacitor includes N series-connected impedance modules, each of which includes a thermal resistor and a thermal capacitor connected in parallel, where N is a positive integer.

[0142] The third acquisition module is used to acquire the thermal resistance value from the hot spot of the DC support capacitor to the cooling medium. The device may further include:

[0143] The first calculation module is used to calculate the product of the thermal resistance value and the thermal capacity value in each impedance module to obtain the thermal temperature coefficient of the impedance module; the thermal resistance value is the resistance value of the thermal resistance in the impedance module, and the thermal capacity value is the capacity value of one thermal capacity in the impedance module.

[0144] The fifth determining module is used to determine the thermal resistance value of the impedance module based on the thermal temperature coefficient.

[0145] The sixth determining module is used to determine the sum of the thermal impedance values ​​of the N impedance modules as the thermal impedance value from the hot spot of the DC support capacitor to the cooling medium.

[0146] In some embodiments, after the first determining module determines the cell temperature value of the DC support capacitor based on the loss value, the temperature value of the cooling medium, and the thermal impedance value, the apparatus may further include:

[0147] The adjustment module is used to adjust at least two of the power factor, modulation ratio, and output current of the vehicle inverter so that the cell temperature of the DC support capacitor is less than or equal to the preset temperature value.

[0148] The various modules of the cell temperature calculation device for the DC-supported capacitor provided in this application embodiment can realize... Figure 2 The functions of each step in the provided method for calculating the cell temperature of the DC support capacitor, and the corresponding technical effects, are described briefly and will not be elaborated here.

[0149] This application also provides an electronic device, such as... Figure 7 As shown, the electronic device 700 may include: a processor 701, a memory 702, a communication interface 703, and a bus 704.

[0150] Specifically, the processor 701 may include a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits that can be configured according to the embodiments of the present application.

[0151] Memory 702 may include mass storage for data or instructions. For example, and not limitingly, memory 702 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. In one embodiment, memory 702 may include removable or non-removable (or fixed) media, or memory 702 may be non-volatile solid-state memory. Memory 702 may be internal or external to the integrated gateway housing device.

[0152] In one embodiment, memory 702 may be read-only memory (ROM). In one embodiment, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically rewritable ROM (EAROM), or flash memory, or a combination of two or more of these.

[0153] Memory 702 may include read-only memory (ROM), random access memory (RAM), disk storage media device, optical storage media device, flash memory device, electrical, optical, or other physical / tangible memory storage device. Therefore, generally, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to one aspect of this disclosure.

[0154] The processor 701 reads and executes computer program instructions stored in the memory 702 to achieve... Figure 2 The methods S201 to S204 in the illustrated embodiment achieve the following: Figure 2 The embodiments shown achieve the corresponding technical effects by performing their methods / steps, which will not be elaborated here for the sake of brevity.

[0155] In one example, the electronic device 700 may also include a communication interface 703 and a bus 704. Wherein, as... Figure 7 As shown, the processor 701, memory 702, and communication interface 703 are connected through bus 704 and complete communication with each other.

[0156] The communication interface 703 is mainly used to realize communication between various modules, devices, units and equipment in the embodiments of the present invention.

[0157] Bus 704 includes hardware, software, or both, that couples together components of an electronic device that embeds a file in a document. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, a Wireless Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable single buses or combinations of two or more of these. Where appropriate, bus 510 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, this application contemplates any suitable bus or interconnect.

[0158] This electronic device can execute the cell temperature monitoring method for the DC-supported capacitor in the embodiments of this application, thereby achieving a combination Figure 2 A method for monitoring the cell temperature of a DC-supported capacitor is described.

[0159] Furthermore, in conjunction with the cell temperature monitoring method for the DC-supported capacitor in the above embodiments, this application embodiment can provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; these computer program instructions are executed by a processor using any of the cell temperature monitoring methods for the DC-supported capacitor in the above embodiments.

[0160] This application also provides a computer program product in which the instructions, when executed by the processor of an electronic device, cause the electronic device to perform various processes implementing any of the above embodiments of the cell temperature monitoring method for DC support capacitors.

[0161] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0162] The functional blocks shown in the above block diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this invention are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, read-only memory (ROM), flash memory, erasable read-only memory (EROM), floppy disks, compact disc read-only memory (CD-ROM), optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0163] It should also be noted that the exemplary embodiments mentioned in this invention describe methods or systems based on a series of steps or apparatus. However, this invention is not limited to the order of the steps described above; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0164] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), electronic devices, and storage media according to embodiments of this application. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to create a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0165] The above description is merely a specific embodiment of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for calculating the cell temperature of a DC-supported capacitor, characterized in that, Applied to vehicle inverters, the method includes: Obtain the loss value of the DC support capacitor; Obtain the temperature value of the cooling medium corresponding to the DC support capacitor; Obtain the thermal resistance value from the hot spot of the DC support capacitor cell to the cooling medium; The cell temperature of the DC support capacitor is determined based on the loss value, the temperature of the cooling medium, and the thermal impedance value. The thermal circuit model of the DC support capacitor includes N series-connected impedance modules, each of which includes a thermal resistor and a thermal capacitor connected in parallel, where N is a positive integer. The step of obtaining the thermal resistance value from the hot spot of the DC support capacitor cell to the cooling medium includes: For each impedance module, the product of the thermal resistance and thermal capacitance in the impedance module is calculated to obtain the thermal temperature coefficient of the impedance module; the thermal resistance is the resistance value of the thermal resistance in the impedance module, and the thermal capacitance is the capacitance value of one thermal capacitance in the impedance module. The thermal impedance value of the impedance module is determined based on the thermal temperature coefficient. The sum of the thermal impedance values ​​of the N impedance modules is determined as the thermal impedance value from the hot spot of the DC support capacitor cell to the cooling medium. The thermal circuit model is used to determine the first variation curve of the DC support capacitor over time, wherein the first temperature value is the value corresponding to the target time point in the first variation curve. Under the same conditions, a second variation curve of the DC support capacitor over time obtained from the simulation experiment is obtained, wherein the second temperature value is the value corresponding to the target time point in the second variation curve; Using at least one first temperature value and a second temperature value, the first change curve and the second change curve are fitted, and the number of impedance modules in the thermal circuit model is determined based on the loss value, dynamic performance and computational load of the DC support capacitor.

2. The method according to claim 1, characterized in that, Determining the cell temperature value of the DC support capacitor based on the loss value, the temperature value of the cooling medium, and the thermal impedance value includes: The cell temperature of the DC-supported capacitor is determined using the following formula: in, This refers to the cell temperature value of the DC support capacitor. The temperature value of the cooling medium. The loss value is... The value is the thermal resistance.

3. The method according to claim 1, characterized in that, Before obtaining the loss value of the DC support capacitor, the method further includes: Obtain the ripple current value of the DC support capacitor; Obtain the equivalent series resistance value of the DC support capacitor; The loss value of the DC support capacitor is determined based on the ripple current value and the equivalent series resistance value of the DC support capacitor.

4. The method according to claim 3, characterized in that, The step of obtaining the ripple current value of the DC support capacitor includes: The power factor, modulation ratio, and output current of the vehicle inverter are obtained, and the vehicle inverter includes the DC support capacitor. The ripple current value of the DC support capacitor is determined based on the power factor, modulation ratio, and output current of the vehicle inverter.

5. The method according to claim 1, characterized in that, After determining the cell temperature of the DC-supported capacitor based on the loss value, the temperature of the cooling medium, and the thermal resistance value, the method further includes: To ensure that the cell temperature of the DC support capacitor is less than or equal to a preset temperature value, adjust at least two of the following values ​​of the vehicle inverter: power factor, modulation ratio, and output current.

6. A cell temperature calculation device for a DC-supported capacitor, characterized in that, The device includes: The first acquisition module is used to acquire the loss value of the DC support capacitor; The second acquisition module is used to acquire the temperature value of the cooling medium corresponding to the DC support capacitor; The third acquisition module is used to acquire the thermal resistance value from the hot spot of the DC support capacitor cell to the cooling medium. The first determining module is used to determine the cell temperature value of the DC support capacitor based on the loss value, the temperature value of the cooling medium, and the thermal resistance value; it is also used to determine the thermal circuit model of the DC support capacitor, which includes N series-connected impedance modules, each impedance module including a thermal resistor and a thermal capacitor connected in parallel, where N is a positive integer; for each impedance module, the product of the thermal resistance value and the thermal capacitor value in the impedance module is calculated to obtain the thermal temperature coefficient of the impedance module; the thermal resistance value is the resistance value of the thermal resistor in the impedance module, and the thermal capacitor value is the capacitance value of the thermal capacitor in the impedance module; the thermal resistance value of the impedance module is determined based on the thermal temperature coefficient; and the sum of the thermal resistance values ​​of the N impedance modules is used to determine the... The thermal impedance value from the hot spot of the DC support capacitor cell to the cooling medium is defined; wherein, through the thermal circuit model, a first variation curve of the DC support capacitor over time is determined, wherein the first temperature value is the value corresponding to the target time point in the first variation curve; under the same conditions, a second variation curve of the DC support capacitor over time obtained from simulation experiments is obtained, wherein the second temperature value is the value corresponding to the target time point in the second variation curve; using at least one first temperature value and a second temperature value, the first variation curve and the second variation curve are fitted, and the number of impedance modules in the thermal circuit model is determined according to the loss value, dynamic performance and computational load of the DC support capacitor.

7. An electronic device, the 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, it performs the cell temperature calculation method for the DC support capacitor as described in any one of claims 1 to 5.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for calculating the cell temperature of the DC support capacitor as described in any one of claims 1 to 5.

9. A computer program product, characterized in that, When the instructions in the computer program product are executed by the processor of the electronic device, the electronic device performs the cell temperature calculation method for the DC support capacitor as described in any one of claims 1 to 5.

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