IGBT Junction Temperature Estimation Method and Device

Abstract

The present invention discloses a method and device for estimating the IGBT junction temperature, which relates to the technical field of IGBT. The present invention determines the equivalent ambient temperature according to the actual ambient temperature of the IGBT in history, determines the theoretical equivalent junction temperature of the IGBT at the current moment according to the equivalent ambient temperature, the equivalent temperatures of each order RC network node in the equivalent fourth-order RC network of the IGBT in history, the theoretical equivalent junction temperature of the IGBT, and the output power of the IGBT, and determines the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment, realizing the estimation of the IGBT junction temperature, and considering the actual ambient temperature of the IGBT when estimating the IGBT junction temperature, improving the accuracy of the IGBT junction temperature estimation.

Description

Technical Field

[0001] The present invention relates to the technical field of IGBTs, and particularly to an IGBT junction temperature estimation method and device. Background Art

[0002] Insulated Gate Bipolar Transistor (IGBT) is a core power device in power electronic systems. The junction temperature of IGBT is closely related to its working performance, life and reliability. Accurate estimation of the IGBT junction temperature is of great significance for improving the reliability of IGBT and extending its service life.

[0003] Current IGBT junction temperature estimation schemes do not consider the actual working environment of IGBTs when estimating the IGBT junction temperature, resulting in large errors and low accuracy of the estimation results. Summary of the Invention

[0004] The present invention solves the technical problem of how to improve the accuracy of IGBT junction temperature estimation by providing an IGBT junction temperature estimation method and device.

[0005] On the one hand, the present invention provides the following technical solution:

[0006] An IGBT junction temperature estimation method, comprising:

[0007] Obtaining the actual environmental temperature at which the IGBT was located historically, the equivalent temperatures of the nodes of each order of the equivalent fourth-order RC network of the IGBT, the theoretical equivalent junction temperature of the IGBT, and the output power of the IGBT;

[0008] Determining an equivalent environmental temperature according to the actual environmental temperature historically;

[0009] According to the equivalent environmental temperature, the equivalent temperatures historically, the theoretical equivalent junction temperature, and the

[0010] output power, determining the theoretical equivalent junction temperature at the current moment;

[0011] Determining the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment;

[0012] The determining the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment includes:

[0013] Obtaining the output power at the current moment and the flow rate of the cooling water in the liquid cooling system of the IGBT;

[0014] Determine the actual equivalent junction temperature at the current moment according to the theoretical equivalent junction temperature, the output power, and the flow rate of the cooling water at the current moment.

[0015] In some embodiments, the actual ambient temperature in history includes the actual ambient temperature at the (N - 4)-th moment, where N is the current moment;

[0016] Determining the equivalent ambient temperature according to the actual ambient temperature in history includes:

[0017] Taking the actual ambient temperature at the (N - 4)-th moment as the equivalent ambient temperature.

[0018] In some embodiments, the actual ambient temperature in history includes the actual ambient temperature at the (N - 5)-th moment, where N is the current moment;

[0019] Determining the equivalent ambient temperature according to the actual ambient temperature in history includes:

[0020] Obtain the actual equivalent junction temperatures at the (N - 5)-th and (N - 4)-th moments;

[0021] Determine the equivalent ambient temperature according to the actual ambient temperature at the (N - 5)-th moment, and the actual equivalent junction temperatures at the (N - 5)-th and (N - 4)-th moments.

[0022] In some embodiments, determining the equivalent ambient temperature according to the actual ambient temperature at the (N - 5)-th moment, and the actual equivalent junctions at the (N - 5)-th and (N - 4)-th moments includes:

[0023] According to the formula Determine the equivalent ambient temperature; where, is the equivalent ambient temperature, is the actual ambient temperature at the (N - 5)-th moment,

[0024] is the actual equivalent junction temperature at the (N - 4)-th moment, is the actual equivalent junction temperature at the (N - 5)-th moment, is the ambient temperature change heat loss coefficient.

[0025] In some embodiments, determining the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment includes:

[0026] Taking the theoretical equivalent junction temperature at the current moment as the actual equivalent junction temperature at the current moment.

[0027] In some embodiments, determining the actual equivalent junction temperature at the current moment according to the theoretical equivalent junction temperature, the output power, and the flow rate of the cooling water at the current moment includes:

[0028] Determining the actual equivalent junction temperature at the current moment according to a preset relationship among the actual equivalent junction temperature, the theoretical equivalent junction temperature, the output power, and the flow rate of the cooling water;

[0029] In the preset relationship, the actual equivalent junction temperature is positively correlated with the theoretical equivalent junction temperature, negatively correlated with the output power, and positively correlated with the flow rate of the cooling water.

[0030] On the other hand, the present invention also provides the following technical solution:

[0031] An IGBT junction temperature estimation device for implementing the above IGBT junction temperature estimation method includes:

[0032] An acquisition module for acquiring the actual ambient temperature of the IGBT in history, the equivalent temperatures of the nodes of each order of the equivalent fourth-order RC network of the IGBT, the theoretical equivalent junction temperature of the IGBT, and the output power of the IGBT;

[0033] A determination module for determining an equivalent ambient temperature according to the actual ambient temperature in history;

[0034] And for determining the theoretical equivalent junction temperature at the current moment according to the equivalent ambient temperature, the equivalent temperatures in history, the theoretical equivalent junction temperature, and the output power;

[0035] And for determining the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment.

[0036] On the other hand, the present invention also provides the following technical solution:

[0037] A computer device includes a memory, a processor, and a computer program stored on the memory, and the processor executes the computer program to implement the steps of any one of the IGBT junction temperature estimation methods described above.

[0038] On the other hand, the present invention also provides the following technical solution:

[0039] A computer-readable storage medium has a computer program stored thereon, and when the computer program is executed by a processor, the steps of any one of the IGBT junction temperature estimation methods described above are implemented.

[0040] One or more technical solutions provided by the present invention have at least the following technical effects or advantages:

[0041] The present invention determines the equivalent ambient temperature according to the actual ambient temperature of the IGBT in history, determines the theoretical equivalent junction temperature of the IGBT at the current moment according to the equivalent ambient temperature, the equivalent temperatures of each order RC network node in the historical IGBT equivalent fourth-order RC network, the theoretical equivalent junction temperature of the IGBT, and the output power of the IGBT, and determines the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment, realizing the estimation of the IGBT junction temperature. Moreover, when estimating the IGBT junction temperature, the actual ambient temperature of the IGBT is considered, improving the accuracy of the IGBT junction temperature estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following described drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0043] Figure 1 It is a schematic diagram of the IGBT equivalent fourth-order RC network in the embodiment of the present invention;

[0044] Figure 2 It is a flowchart of the IGBT junction temperature estimation method in the embodiment of the present invention;

[0045] Figure 3 It is a schematic diagram of the liquid cooling system of the IGBT in the embodiment of the present invention;

[0046] Figure 4 It is a schematic diagram of the IGBT junction temperature estimation device in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] The embodiments of the present invention provide an IGBT junction temperature estimation method and device, solving the technical problem of how to improve the accuracy of IGBT junction temperature estimation.

[0048] In order to better understand the technical solutions of the present invention, the following will combine the specification drawings and specific implementation manners to detail the technical solutions of the present invention.

[0049] The physical structure of the IGBT generally consists of packaging structures such as copper plates, solder layers, liner plates, and substrates, and its basic physical characteristics can be equivalent to an electrical model of a resistor in parallel with a capacitor. In the embodiments of the present invention, a fourth-order RC parallel network is used to perform electrical modeling on the IGBT physical structure, obtaining the equivalent fourth-order RC network of the IGBT as shown in Figure 1 The fourth-order RC network respectively equivalently replaces physical structures such as copper plates, solder layers, liner plates, and substrates, is a resistor, is a capacitor. The output power P of the IGBT in the electrical system is applied across the equivalent fourth-order RC network. Figure 1 in is the theoretical equivalent junction temperature of the IGBT. The nodes where they are located are the first-order RC network node, the second-order RC network node, the third-order RC network node, and the fourth-order RC network node respectively. are the equivalent temperatures of the first-order RC network node, the second-order RC network node, the third-order RC network node, and the fourth-order RC network node respectively. Since the physical structure corresponding to the fourth-order RC network node is in contact with the environment, the equivalent temperature of the fourth-order RC network node is the equivalent ambient temperature where the IGBT is located. , The initial value of is generally taken as 25 °C.

[0050] According to Kirchhoff's first law, we can obtain Figure 1 the mathematical differential model of the equivalent fourth-order RC network:

[0051] ; where t is time.

[0052] Discretizing the time of this mathematical differential model at the current time N gives the discrete equation:

[0053] ;

[0054] In the formula, are the theoretical equivalent junction temperature at the current time N and the theoretical equivalent junction temperature at the (N - 1)th time respectively. are the equivalent temperatures of the first-order RC network node at the Nth time and the equivalent temperature of the first-order RC network node at the (N - 1)th time respectively. are the equivalent temperatures of the second-order RC network node at the Nth time and the equivalent temperature of the second-order RC network node at the (N - 1)th time respectively. are the equivalent temperatures of the third-order RC network node at the Nth time and the equivalent temperature of the third-order RC network node at the (N - 1)th time respectively. is the IGBT output power at the (N - 1)th time, which is calculated from the voltage and current flowing through the collector and emitter of the IGBT at the (N - 1)th time; ∆t is the sampling time interval.

[0055] Theoretical equivalent junction temperature , equivalent temperature, equivalent ambient temperature The units of are °C, the unit of the IGBT output power 𝑃 is W, and the unit of the sampling time interval ∆t is s. All can be obtained from the IGBT data sheet.

[0056] Deriving the discrete equation yields the difference equation:

[0057] ;

[0058] wherein, is the theoretical equivalent junction temperature at the (N - 2)-th moment; are respectively the equivalent temperatures of the first-order RC network node at the (N - 2)-th moment and the equivalent temperature of the first-order RC network node at the (N - 3)-th moment; are respectively the equivalent temperatures of the second-order RC network node at the (N - 2)-th moment, the equivalent temperature of the second-order RC network node at the (N - 3)-th moment, and the equivalent temperature of the second-order RC network node at the (N - 4)-th moment; are respectively the equivalent temperatures of the third-order RC network node at the (N - 3)-th moment and the equivalent temperature of the third-order RC network node at the (N - 4)-th moment.

[0059] Based on the above difference equation, the IGBT junction temperature estimation method as shown in Figure 2 can be obtained, including:

[0060] Step S1: Obtain the actual ambient temperature of the IGBT in history, the equivalent temperatures of each order RC network node in the equivalent fourth-order RC network of the IGBT, the theoretical equivalent junction temperature of the IGBT, and the output power of the IGBT;

[0061] Step S2: Determine the equivalent ambient temperature according to the actual ambient temperature in history;

[0062] Step S3: Determine the theoretical equivalent junction temperature at the current moment according to the equivalent ambient temperature, the equivalent temperatures in history, the theoretical equivalent junction temperature, and the output power;

[0063] Step S4: Determine the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment.

[0064] In step S1, the equivalent temperatures in history include the equivalent temperature of the first-order RC network node at the (N - 3)-th moment and the equivalent temperature at the (N - 2)-th moment , the equivalent temperatures of the second-order RC network node at

[0065] the (N - 4)-th moment and the equivalent temperature at the (N - 3)-th moment , the equivalent temperature of the third-order RC network node at the (N - 4)-th moment ; the theoretical equivalent junction temperatures in history include the theoretical equivalent junction temperature at the (N - 2)-th moment and the theoretical equivalent junction temperature at the (N - 1)-th moment ; the output powers in history include the output power at the (N - 1)-th moment 。

[0066] It should be noted that the actual ambient temperature, equivalent temperature, theoretical equivalent junction temperature, and output power in history can all be regarded as known and initial values can be assigned.

[0067] Let the actual ambient temperature where the IGBT is located be T. In some embodiments, the actual ambient temperature in history may include the actual ambient temperature at the (N - 4)-th moment , where N is the current moment; step S2 may include: taking the actual ambient temperature at the (N - 4)-th moment as the equivalent ambient temperature . Then the above difference equation becomes:

[0068] ;

[0069] Step S3 can calculate the theoretical equivalent junction temperature at the current moment according to the above difference equation , and the specific process is: substituting the actual ambient temperature at the (N - 4)-th moment , the equivalent temperature of the second-order RC network node at the (N - 4)-th moment and the equivalent temperature of the third-order RC network node at the (N - 4)-th moment into the formula in the difference equation to calculate the equivalent temperature of the third-order RC network node at the (N - 3)-th moment ;

[0070] Substituting the equivalent temperature of the first-order RC network node at the (N - 3)-th moment , the equivalent temperature of the second-order RC network node at the (N - 3)-th moment and the equivalent temperature of the third-order RC network node at the (N - 3)-th moment into the formula in the difference equation to calculate the equivalent temperature of the second-order RC network node at the (N - 2)-th moment ;

[0071] Substituting the theoretical equivalent junction temperature at the (N - 2)-th moment , the equivalent temperature of the first-order RC network node at the (N - 2)-th moment and the equivalent temperature of the second-order RC network node at the (N - 2)-th moment into the formula in the difference equation to calculate the equivalent temperature of the first-order RC network node at the (N - 1)-th moment ;

[0072] Substituting the output power at the (N - 1)-th moment , the theoretical equivalent junction temperature at the (N - 1)-th moment and the equivalent temperature of the first-order RC network node at the (N-1)th moment Substitute the formula into the difference equation Calculate the theoretical equivalent junction temperature at the current moment .

[0073] In some embodiments, step S4 may include: using the theoretical equivalent junction temperature at the current moment as the actual equivalent junction temperature at the current moment . In this way, the junction temperature estimation of the IGBT is realized, and the actual ambient temperature where the IGBT is located is considered when estimating the junction temperature of the IGBT, which can improve the accuracy of the IGBT junction temperature estimation.

[0074] As mentioned above, step S2 may use the actual ambient temperature at the (N-4)th moment as the equivalent ambient temperature . However, in the actual working environment of the IGBT, the actual ambient temperature sometimes cannot represent the equivalent ambient temperature. In this case, using the actual ambient temperature at the (N-4)th moment as the equivalent ambient temperature will reduce the accuracy of the IGBT junction temperature estimation. To further improve the accuracy of the IGBT junction temperature estimation, in some embodiments, the actual ambient temperature in history may further include the actual ambient temperature at the (N-5)th moment, and step S2 may further include:

[0075] Obtain the actual equivalent junction temperatures at the (N-5)th and (N-4)th moments;

[0076] Determine the equivalent ambient temperature according to the actual ambient temperature at the (N-5)th moment, the actual equivalent junction temperatures at the (N-5)th and (N-4)th moments.

[0077] It should be noted that the actual equivalent junction temperatures at the (N-5)th and (N-4)th moments can both be regarded as known and can be assigned initial values.

[0078] In some embodiments, determining the equivalent ambient temperature according to the actual ambient temperature at the (N-5)th moment , the actual equivalent junction temperatures at the (N-5)th and (N-4)th moments , may include: determining the equivalent ambient temperature according to the formula ; where is the actual ambient temperature at the (N-5)th moment, is the actual equivalent junction temperature at the (N-4)th moment, is the actual equivalent junction temperature at the (N-5)th moment, is the ambient temperature change heat loss coefficient and is a non-linear function.

[0079] Where is actually the change in the actual equivalent junction temperature in history, which is equivalent to correcting the actual ambient temperature at the (N - 5)-th moment according to the change in the actual equivalent junction temperature in history 。

[0080] As mentioned above, step S4 can use the theoretical equivalent junction temperature at the current moment as the actual equivalent junction temperature at the current moment 。However, in the actual working environment of the IGBT, there is a liquid cooling system that exchanges heat with the IGBT to control the temperature of the IGBT, as Figure 3 shown. An increase in the temperature of the cooling water in the liquid cooling system will cause a decrease in the temperature of the IGBT, that is, the actual equivalent junction temperature of the IGBT should be lower than the theoretical equivalent junction temperature. A decrease in the temperature of the cooling water will cause an increase in the temperature of the IGBT, that is, the actual equivalent junction temperature of the IGBT should be higher than the theoretical equivalent junction temperature. If the theoretical equivalent junction temperature is directly regarded as the actual equivalent junction temperature of the IGBT , the accuracy of IGBT junction temperature estimation will be reduced. To further improve the accuracy of IGBT junction temperature estimation, in some embodiments, step S4 may further include:

[0081] Obtain the IGBT output power at the current moment and the flow rate of the cooling water in the liquid cooling system of the IGBT;

[0082] Determine the actual equivalent junction temperature at the current moment according to the theoretical equivalent junction temperature, output power, and flow rate of the cooling water at the current moment.

[0083] In some embodiments, determining the actual equivalent junction temperature at the current moment according to the theoretical equivalent junction temperature, output power, and

[0084] flow rate of the cooling water may include:

[0085] Determine the actual equivalent junction temperature at the current moment according to the preset relationship between the actual equivalent junction temperature, theoretical equivalent junction temperature, output power, and flow rate of the cooling water;

[0086] In the preset relationship, the actual equivalent junction temperature is positively correlated with the theoretical equivalent junction temperature, negatively correlated with the output power, and positively correlated with the flow rate of the cooling water.

[0087] In some embodiments, the preset relationship may be: ; where is the actual equivalent junction temperature at the current moment, is the IGBT output power at the current moment, is the flow rate of the cooling water, is the density of the cooling water, is the specific heat capacity of the cooling water, is the heat loss coefficient due to the temperature change of the cooling water. In some embodiments, can range from 0.6 to 0.9. In the formula, corresponds to the temperature change of the cooling water. When the temperature of the cooling water rises, the temperature change is positive, and when the temperature of the cooling water drops, the temperature change is negative. Therefore, when estimating the IGBT junction temperature, the temperature change of the cooling water in the liquid cooling system is considered, improving the accuracy of IGBT junction temperature estimation.

[0088] As Figure 4 shown, the embodiments of the present invention also provide an IGBT junction temperature estimation device, including:

[0089] An acquisition module, configured to acquire the actual ambient temperature where the IGBT is located historically, the equivalent temperatures of each order RC network node in the equivalent fourth-order RC network of the IGBT, the theoretical equivalent junction temperature of the IGBT, and the output power of the IGBT;

[0090] A determination module, configured to determine the equivalent ambient temperature according to the actual ambient temperature historically;

[0091] And configured to determine the theoretical equivalent junction temperature at the current moment according to the equivalent ambient temperature, the equivalent temperatures historically, the theoretical equivalent junction temperature, and the output power;

[0092] And configured to determine the actual equivalent 20 junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment.

[0093] In some embodiments, the actual ambient temperature historically may include the actual ambient temperature at the (N - 4)-th moment, where N is the current moment;

[0094] The determination module may specifically be configured to:

[0095] Take the actual ambient temperature at the (N - 4)-th moment as the equivalent ambient temperature.

[0096] In some embodiments, the actual ambient temperature historically may include the actual ambient temperature at the (N - 5)-th moment, where N is the current moment;

[0097] The determination module may specifically be configured to:

[0098] Acquire the actual equivalent junction temperatures at the (N - 5)-th and (N - 4)-th moments;

[0099] Determine the equivalent ambient temperature according to the actual ambient temperature at the (N - 5)-th moment, the actual equivalent junction temperatures at the (N - 5)-th and (N - 4)-th moments.

[0100] In some embodiments, the determination module may further be configured to:

[0101] According to the formula Determine the equivalent ambient temperature; wherein, is the equivalent ambient temperature, is the actual ambient temperature at the (N - 5)th moment, is the actual equivalent junction temperature at the (N - 4)th moment, is the actual equivalent junction temperature at the (N - 5)th moment, is the ambient temperature change heat loss coefficient.

[0102] In some embodiments, the determining module can be specifically configured to:

[0103] Take the theoretical equivalent junction temperature at the current moment as the actual equivalent junction temperature at the current moment.

[0104] In some embodiments, the determining module can be specifically configured to:

[0105] Obtain the output power at the current moment and the flow rate of the cooling water in the liquid cooling system of the IGBT;

[0106] Determine the actual equivalent junction temperature at the current moment according to the theoretical equivalent junction temperature, output power, and flow rate of the cooling water at the current moment.

[0107] In some embodiments, the determining module can also be used to:

[0108] Determine the actual equivalent junction temperature at the current moment according to the preset relationship between the actual equivalent junction temperature, theoretical equivalent junction temperature, output power, and flow rate of the cooling water;

[0109] In the preset relationship, the actual equivalent junction temperature is positively correlated with the theoretical equivalent junction temperature, negatively correlated with the output power,

[0110] and positively correlated with the flow rate of the cooling water.

[0111] Based on the same inventive concept as the IGBT junction temperature estimation method described above, an embodiment of the present invention further provides a computer device, including a memory, a processor, and a computer program stored on the memory. The processor executes the computer program to implement the steps of any of the IGBT junction temperature estimation methods described above.

[0112] Since the computer device introduced in the embodiment of the present invention is the computer device used to implement the IGBT junction temperature estimation method in the embodiment of the present invention, based on the IGBT junction temperature estimation method described in the embodiment of the present invention, those skilled in the art can understand the specific implementation manners and various variations of the computer device in the embodiment of the present invention. Therefore, the specific implementation of how the computer device implements the method in the embodiment of the present invention will not be described in detail here. As long as the computer device used by those skilled in the art to implement the IGBT junction temperature estimation method in the embodiment of the present invention falls within the scope of protection of the present invention.

[0113] Based on the same inventive concept as the IGBT junction temperature estimation method described above, the present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of any one of the IGBT junction temperature estimation methods described above are implemented.

[0114] Those skilled in the art should understand that the embodiments of the present invention may be provided as a method, a system, or a computer program product. Therefore, the present invention may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0115] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that

[0116] the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 block or multiple blocks.

[0117] These computer program instructions can also be stored in a computer-readable memory capable of guiding a computer or other programmable data processing devices to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implement the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 block or multiple blocks.

[0118] These computer program instructions can also be loaded onto a computer or other programmable data processing devices, such that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable devices provide steps for implementing the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 block or multiple blocks.

[0119] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn of the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention.

[0120] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for estimating IGBT junction temperature, characterized in that: include: Obtaining the actual ambient temperature of the IGBT in history, the equivalent temperature of each RC network node in the equivalent fourth-order RC network of the IGBT, the theoretical equivalent junction temperature of the IGBT and the output power of the IGBT; Determine the equivalent ambient temperature based on the historical actual ambient temperature; Determine the theoretical equivalent junction temperature at the current moment according to the equivalent ambient temperature, the historical equivalent temperature, the theoretical equivalent junction temperature, and the output power; Determine the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment; The determining the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment includes: Obtaining the output power at the current moment and the flow rate of cooling water in the liquid cooling system of the IGBT; The actual equivalent junction temperature at the current moment is determined according to the theoretical equivalent junction temperature at the current moment, the output power, and the flow rate of the cooling water.

2. The IGBT junction temperature estimation method according to claim 1, characterized in that: The actual ambient temperature in history includes the actual ambient temperature at the N-4th moment, where N is the current moment; The determining of the equivalent ambient temperature according to the historical actual ambient temperature comprises: The actual ambient temperature at the N-4th moment is used as the equivalent ambient temperature.

3. The IGBT junction temperature estimation method according to claim 1, characterized in that: The actual ambient temperature in history includes the actual ambient temperature at the N-5th moment, where N is the current moment; The determining of the equivalent ambient temperature according to the historical actual ambient temperature comprises: Obtaining the actual equivalent junction temperature at the N-5th and N-4th moments; The equivalent ambient temperature is determined according to the actual ambient temperature at the N-5th moment and the actual equivalent junction temperatures at the N-5th and N-4th moments.

4. The IGBT junction temperature estimation method according to claim 3, characterized in that: The determining the equivalent ambient temperature according to the actual ambient temperature at the N-5th moment and the actual equivalent junctions at the N-5th and N-4th moments includes: According to the formula Determine the equivalent ambient temperature; wherein, is the equivalent ambient temperature, is the actual ambient temperature at the N-5th moment, is the actual equivalent junction temperature at the N-4th moment, is the actual equivalent junction temperature at the N-5th moment, is the heat loss coefficient due to ambient temperature change.

5. The IGBT junction temperature estimation method according to claim 1, characterized in that: The determining the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment includes: The theoretical equivalent junction temperature at the current moment is used as the actual equivalent junction temperature at the current moment.

6. The IGBT junction temperature estimation method according to claim 1, characterized in that: The determining the actual equivalent junction temperature at the current moment according to the theoretical equivalent junction temperature at the current moment and the output power and the flow rate of the cooling water includes: Determining the actual equivalent junction temperature at the current moment according to a preset relationship between the actual equivalent junction temperature and the theoretical equivalent junction temperature, the output power, and the flow rate of the cooling water; In the preset relationship, the actual equivalent junction temperature is positively correlated with the theoretical equivalent junction temperature, negatively correlated with the output power, and positively correlated with the flow rate of the cooling water.

7. An IGBT junction temperature estimation device, used to implement the IGBT junction temperature estimation method according to claim 1, characterized in that: include: An acquisition module is used to acquire the actual ambient temperature of the IGBT in history, the equivalent temperature of each RC network node in the equivalent fourth-order RC network of the IGBT, the theoretical equivalent junction temperature of the IGBT and the output power of the IGBT; A determination module, used for determining an equivalent ambient temperature according to the historical actual ambient temperature; and for determining the theoretical equivalent junction temperature at a current moment according to the equivalent ambient temperature, the historical equivalent temperature, the theoretical equivalent junction temperature and the output power; And used to determine the actual equivalent junction temperature of the IGBT at the current moment according to the theoretical equivalent junction temperature at the current moment.

8. A computer device, characterized in that: The invention comprises a memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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