A method and system for evaluating junction temperature and power loss of an IGBT module

Abstract

The present invention discloses an evaluation method and system for junction temperature and power loss of an IGBT module. The method comprises selecting several terminals of an IGBT module according to a preset selection rule; wherein the number of terminals is obtained according to the number of power chips in the IGBT module; performing a characteristic experiment on the IGBT module, and establishing a thermal model according to the thermal coefficient from a specific chip to each terminal; performing junction temperature transfer calculation on the thermal model to obtain an inverse matrix of transfer coefficients; placing the IGBT module in a field operating condition, measuring the current temperature of each terminal of the IGBT module, and online estimating each current temperature and the inverse matrix of transfer coefficients to obtain the junction temperature and power loss of the IGBT module. This embodiment realizes rapid evaluation of the junction temperature and power loss of the IGBT module, reduces the amount of online calculations, and improves the evaluation accuracy.

Description

Technical Field

[0001] The present invention relates to the field of IGBT module evaluation, and in particular to an evaluation method and system for junction temperature and power loss of an IGBT module. Background Art

[0002] Insulated gate bipolar transistor (IGBT) modules are widely used in medium and high power applications such as renewable energy power generation, traction systems and industrial drives. Due to the influence of long-term thermal mechanical stress, IGBT modules are prone to package aging and even failure. In order to improve the reliability of IGBT operation, there are many health status monitoring and active thermal management technologies. The key to the implementation of these technologies is to obtain the junction temperature information of the power chip in the IGBT module, so accurate assessment of the junction temperature is crucial to the reliability of the IGBT.

[0003] In order to evaluate the junction temperature of IGBT modules, the existing methods based on reference point temperature measurement need to calculate the chip power loss, which requires many iterations and large amount of calculation, making it difficult to apply in situations where real-time requirements are high. In addition, the IGBT thermal models used in these methods will change with the aging parameters of the package, resulting in errors in the junction temperature estimation, and the accuracy of the junction temperature evaluation is not high. Summary of the invention

[0004] The present invention provides an evaluation method and system for the junction temperature and power loss of an IGBT module, which can realize rapid evaluation of the junction temperature and power loss of the IGBT module, reduce the amount of online calculation, and improve the evaluation accuracy.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a method for evaluating junction temperature and power loss of an IGBT module, comprising:

[0006] According to a preset selection rule, a number of terminals of the IGBT module are selected; wherein the number of terminals is obtained according to the number of power chips in the IGBT module;

[0007] Conduct characterization experiments on the IGBT module and establish a thermal model based on the thermal coefficient from the specific chip to each terminal;

[0008] The thermal model is used to calculate the junction temperature transfer and obtain the inverse matrix of the transfer coefficient;

[0009] The IGBT module is placed in the field operating conditions, the current temperature of each terminal of the IGBT module is measured, and each current temperature and the inverse matrix of the transfer coefficient are estimated online to obtain the junction temperature and power loss of the IGBT module.

[0010] In the implementation of the embodiment of the present invention, several terminals of the IGBT module are selected according to the preset selection rules; wherein the number of terminals is obtained according to the number of power chips in the IGBT module; the IGBT module is subjected to a characteristic experiment, and a thermal model is established according to the thermal coefficient from a specific chip to each terminal; the thermal model is subjected to junction temperature transfer calculation to obtain an inverse matrix of transfer coefficients; the IGBT module is placed in a field operation condition, the current temperature of each terminal of the IGBT module is measured, and each current temperature and the inverse matrix of transfer coefficients are estimated online to obtain the junction temperature and power loss of the IGBT module. For the same IGBT module, the characteristic experiment under laboratory conditions only needs to be carried out once, and the online calculation of the junction temperature under field operation conditions can be realized, and the iterative calculation of the device loss does not need to be carried out in the process, and the rapid evaluation of the junction temperature can be achieved with a very small amount of calculation. The field operation online calculation only needs to measure the temperature of several terminals, and does not need to measure the electrical parameters of the IGBT, and can be electrically isolated from the main circuit to avoid the measurement and evaluation process being affected by the main circuit. For IGBT modules with aged solder layers, since the heat flow path from the chip to each terminal has little to do with the solder layer, the accuracy of the junction temperature assessment will not be affected by aging, thereby improving the accuracy of the assessment data.

[0011] As a preferred solution, the IGBT module is subjected to a characteristic experiment, and a thermal model is established based on the thermal coefficient from a specific chip to each terminal, specifically:

[0012] Performing a characteristic experiment on the current power chip in the IGBT module to obtain the power loss of the current power chip and measuring the current first temperature data; wherein, during the characteristic experiment, only one power chip generates power loss at the same time;

[0013] Calculate the current first temperature data and the power loss of the current power chip to obtain the thermal coefficient from the specific chip to each terminal under the thermal effect of the current power chip; wherein the current first temperature data includes the current first junction temperature of the specific chip and the current first temperature of each terminal;

[0014] By conducting characteristic experiments on all power chips of the IGBT module, the thermal coefficient from a specific chip to each terminal under the thermal effect of each power chip is calculated, the total thermal coefficient is obtained, and a thermal model is constructed based on the total thermal coefficient.

[0015] As a preferred solution, the current power chip in the IGBT module is subjected to a characteristic experiment to obtain the power loss of the current power chip, specifically:

[0016] According to the characteristic experimental circuit, connect the IGBT module to the preset position;

[0017] The preset switch is closed, the gate driver applies a high-level signal, the IGBT module is turned on, and the DC power supply operates in the current source mode;

[0018] When the current flowing through the current power chip reaches a preset current value, the voltage across the current power chip is measured to obtain the current voltage;

[0019] The current voltage and the preset current value are numerically calculated to obtain the current power loss of the power chip.

[0020] As a preferred solution, the current first temperature data and the power loss of the current power chip are calculated to obtain the thermal coefficient from the specific chip to each terminal under the thermal effect of the current power chip, specifically:

[0021] …;

[0022] Among them, r kn is the thermal coefficient of terminal k, T tk is the current first temperature of terminal k, P n is the power loss of power chip n, T j is the current first junction temperature of a specific chip, n is the number of power chips, indicating power chip n, and k is the number of terminals, indicating terminal k.

[0023] As a preferred solution, the thermal model is used to calculate the junction temperature transfer to obtain the inverse matrix of the transfer coefficient, which is specifically:

[0024] Thermal model, specifically:

[0025] RY=X

[0026] Wherein, X is a column matrix of the temperature of each terminal, Y is a column matrix of the junction temperature of a specific chip and the power loss of a power chip, and R is a first transfer coefficient matrix; wherein the first transfer coefficient matrix is ​​obtained according to all thermal coefficients;

[0027] According to the thermal model, the inverse matrix corresponding to the first transfer coefficient matrix is ​​calculated to obtain the transfer coefficient inverse matrix.

[0028] As a preferred solution, the IGBT module is placed in a field operating condition and the current temperature of each terminal of the IGBT module is measured, specifically:

[0029] The IGBT module is placed in a field operating condition, a temperature sensor is placed on each terminal, and the current temperature of each terminal of the IGBT module is measured by each temperature sensor.

[0030] As a preferred solution, each current temperature and the inverse matrix of the transfer coefficient are estimated online to obtain the junction temperature and power loss of the IGBT module, specifically:

[0031] According to each current temperature, the terminal online temperature matrix is ​​obtained;

[0032] The transfer coefficient inverse matrix and the terminal online temperature matrix are matrix-producted to obtain the junction temperature and power loss of the IGBT module.

[0033] As a preferred solution, the number of terminals is obtained according to the number of power chips in the IGBT module, specifically:

[0034] Count the number of all power chips in the IGBT module to get the first number;

[0035] Add 1 to the first number to get the number of terminals.

[0036] As a preferred solution, the selection rules are preset, specifically:

[0037] The thermal effect generated by the power loss of each power chip affects each terminal to a different extent, ensuring that the thermal characteristics between the terminals are different.

[0038] In order to solve the same technical problem, an embodiment of the present invention also provides an evaluation system for junction temperature and power loss of an IGBT module, comprising: a selection unit, a characteristic experiment unit, a matrix calculation unit and an online estimation unit;

[0039] The selection unit is used to select a number of terminals of the IGBT module according to a preset selection rule; wherein the number of terminals is obtained according to the number of power chips in the IGBT module;

[0040] The characteristic experiment unit is used to conduct characteristic experiments on IGBT modules and establish a thermal model based on the thermal coefficient from specific chips to each terminal;

[0041] The matrix calculation unit is used to perform junction temperature transfer calculation on the thermal model to obtain the inverse matrix of transfer coefficients;

[0042] The online estimation unit is used to place the IGBT module in field operating conditions, measure the current temperature of each terminal of the IGBT module, and perform online estimation of each current temperature and the inverse matrix of the transfer coefficient to obtain the junction temperature and power loss of the IGBT module. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 : A flow chart of an embodiment of a method for evaluating junction temperature and power loss of an IGBT module provided by the present invention;

[0044] Figure 2 : A simplified flow chart of an evaluation method for evaluating junction temperature and power loss of an IGBT module provided by the present invention according to an embodiment;

[0045] Figure 3 : A structural diagram of a two-chip IGBT module according to an embodiment of a method for evaluating junction temperature and power loss of an IGBT module provided by the present invention;

[0046] Figure 4 : A structural diagram of an IGBT half-bridge module according to another embodiment of a method for evaluating junction temperature and power loss of an IGBT module provided by the present invention;

[0047] Figure 5 : A characteristic experiment circuit diagram of an embodiment of a method for evaluating junction temperature and power loss of an IGBT module provided by the present invention;

[0048] Figure 6 : A structural schematic diagram of an embodiment of an IGBT module junction temperature and power loss evaluation system provided by the present invention. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Embodiment 1

[0051] Please refer to Figure 1 , is a flow chart of a method for evaluating the junction temperature and power loss of an IGBT module provided by an embodiment of the present invention, wherein a simplified evaluation process is as follows: Figure 2 The evaluation method of this embodiment is applicable to insulated gate bipolar transistor modules. This embodiment implements online calculation evaluation through characteristic experiments and thermal models, quickly evaluates the junction temperature and power loss of the IGBT module, reduces the amount of online calculation, and improves the evaluation accuracy. The evaluation method includes steps 101 to 104, and each step is as follows:

[0052] Step 101: Select several terminals of the IGBT module according to a preset selection rule; wherein the number of the terminals is obtained according to the number of power chips in the IGBT module.

[0053] Optionally, a selection rule is preset, specifically: the thermal effect generated by the power loss of each power chip affects each terminal to a different extent, ensuring that the thermal characteristics of each terminal are different.

[0054] Optionally, the number of terminals is obtained according to the number of power chips in the IGBT module, specifically: the number of all power chips in the IGBT module is counted to obtain a first number; and 1 is added to the first number to obtain the number of terminals.

[0055] In this embodiment, for an IGBT module having N power chips (power semiconductor chips), K terminals are selected, and K terminals are appropriately selected from a total of M terminals of a power IGBT module. The preset selection rule is that the thermal effect generated by the power loss of different chips has different degrees of influence on the selected terminals, ensuring that the thermal characteristics of each terminal are different. The number K is (N+1).

[0056] As an example of this embodiment, for an IGBT module including two power semiconductor chips (one IGBT chip and one anti-parallel diode FWD chip), the structure of the two-chip IGBT module is as follows: Figure 3 As shown in the figure, R 1t , R 2t Respectively represent the thermal resistance from IGBT chip and FWD chip to the terminal, R ta It is the thermal resistance from the terminal to the external environment, R 1a , R 2a They represent the thermal resistance from the IGBT chip and FWD chip to the environment, which includes all heat flow paths except the terminals. t Indicates the terminal temperature, T a Indicates the ambient temperature. In order to evaluate the junction temperature of the IGBT chip, three terminals are selected, and it is required that the thermal effect caused by the power loss of different chips has different degrees of influence on the selected terminals.

[0057] It should be noted that the ambient temperature is only a parameter in the IGBT module structure diagram and does not need to be measured; the thermal coefficient in the steady state obtained in the characteristic experiment is a constant, so there is no need to consider the influence of the ambient temperature.

[0058] As another example of this embodiment, Figure 4 As shown in the figure, the IGBT half-bridge module structure, in which QA and DA, QB and DB represent the IGBT and diode of the upper and lower bridge arms respectively, TCA, TCB, TE represent the power terminals respectively, and TGA, TEA, TGB, TEB represent the drive terminals respectively. Figure 4 In an IGBT module with 4 power semiconductor chips, 5 terminals need to be selected, and the gate of QA (T GA ), QA's collector (T CA ), QB's gate (T GB ), QB's collector (T CB ), QB's emitter (T E). The thermal characteristics of these five terminals to each chip are different, so there are obvious differences between the temperatures of each terminal, that is, there are differences between the thermal coefficients, making the transfer coefficient matrix R reversible.

[0059] Step 102: Conduct a characteristic experiment on the IGBT module and establish a thermal model based on the thermal coefficient from the specific chip to each terminal.

[0060] In this embodiment, a characteristic experiment is performed under laboratory conditions to obtain a thermal model from a specific chip (specific semiconductor chip SC) to each terminal.

[0061] Optionally, step 102 specifically includes step 1021 to step 1023, each step is as follows:

[0062] Step 1021: Perform a characteristic experiment on the current power chip in the IGBT module to obtain the power loss of the current power chip and measure the current first temperature data; wherein, during the characteristic experiment, only one power chip generates power loss at the same time.

[0063] In this embodiment, when performing the characteristic experiment, power loss is generated in only one semiconductor chip of the IGBT module at the same time. The thermal effects generated by the power losses of different chips will be coupled with each other. n By measuring the junction temperature T of a specific chip SC j As well as the terminal temperatures selected in step 101, the thermal coefficient from the specific chip SC to each terminal under the thermal effect of chip n alone can be obtained.

[0064] Optionally, a characteristic experiment is performed on the current power chip in the IGBT module to obtain the power loss of the current power chip, specifically: according to the characteristic experiment circuit, the IGBT module is connected to a preset position; the preset switch is closed, and the gate driver applies a high-level signal to turn on the IGBT module, and the DC power supply operates in a current source mode; when the current flowing through the current power chip reaches a preset current value, the voltage across the current power chip is measured to obtain the current voltage; the current voltage and the preset current value are numerically calculated to obtain the power loss of the current power chip.

[0065] As an example of this embodiment, Figure 5The characteristic experiment circuit diagram shown in the figure connects the IGBT module between the ce terminals in the figure, and power loss is generated in only one power semiconductor chip at the same time. When switches S1 and S4 are closed, the gate driver applies a high-level signal, the IGBT module is turned on, and the DC power supply operates in the current source mode. The current flowing through the IGBT chip reaches the set value, that is, the preset current value. The voltage across the power chip is measured by voltage detection, and multiplied by the current to obtain the power loss of the IGBT chip. Similarly, when switches S2 and S3 are closed, power loss is generated in the diode chip. In addition, during the experiment, the IGBT chip, as a specific chip of the current IGBT module, also needs to monitor the junction temperature of the IGBT chip and the selected three terminal temperatures.

[0066] Step 1022: Calculate the current first temperature data and the power loss of the current power chip to obtain the thermal coefficient from the specific chip to each terminal under the thermal effect of the current power chip; wherein the current first temperature data includes the current first junction temperature of the specific chip and the current first temperature of each terminal.

[0067] Optional, …;

[0068] Among them, r kn is the thermal coefficient of terminal k, T tk is the current first temperature of terminal k, P n is the power loss of power chip n, T j is the current first junction temperature of a specific chip, n is the number of power chips, indicating power chip n, and k is the number of terminals, indicating terminal k.

[0069] As an example of this embodiment, a power loss P1 is generated in the IGBT chip of the IGBT module, and the junction temperature T of the IGBT is measured. j and 3 terminal temperatures T tk , the thermal coefficient from IGBT to each terminal under the thermal effect of IGBT chip can be obtained:

[0070]

[0071] The power loss P2 is generated in the diode chip of the IGBT module, and the junction temperature T of the IGBT is measured. j and 3 terminal temperatures T tk , the thermal coefficient from IGBT to each terminal under the thermal effect of the diode chip can be obtained:

[0072]

[0073] Step 1023: By performing characteristic experiments on all power chips of the IGBT module, the thermal coefficient from a specific chip to each terminal under the thermal effect of each power chip is calculated to obtain the total thermal coefficient, and a thermal model is constructed based on the total thermal coefficient.

[0074] In this embodiment, steps 1021 to 1022 are repeated for each power chip in an IGBT module to obtain the thermal coefficients of the specific chip SC to K terminals under the thermal effects of different power chips, that is, to obtain all thermal coefficients.

[0075] Step 103: Calculate the junction temperature transfer of the thermal model to obtain an inverse matrix of the transfer coefficient.

[0076] In this embodiment, the transfer coefficient matrix R from the junction temperature of a specific chip SC to the temperature of each terminal is derived according to the thermal model, and its inverse matrix, i.e., the transfer coefficient inverse matrix R is calculated. -1 .

[0077] Optional, thermal model, specifically:

[0078] RY=X

[0079] Wherein, X is a column matrix of the temperature of each terminal, Y is a column matrix of the junction temperature of a specific chip and the power loss of a power chip, and R is a first transfer coefficient matrix; wherein the first transfer coefficient matrix is ​​obtained according to all thermal coefficients;

[0080] According to the thermal model, the inverse matrix corresponding to the first transfer coefficient matrix is ​​calculated to obtain the transfer coefficient inverse matrix.

[0081] In this embodiment, the thermal coefficient formula in step 1022 is transformed to obtain:

[0082]

[0083] Among them, T j , P n 、T tk The parameters are variables, r kn etc. are constants.

[0084] By repeating the characteristic test steps for each chip in an IGBT module, the thermal coefficients from SC to K terminals under the thermal effects of different chips can be obtained, and then the thermal model from SC to each terminal can be obtained:

[0085]

[0086] The first transfer coefficient matrix R is derived from the thermal model of the specific chip SC to each terminal:

[0087]

[0088] That is, RY = X;

[0089] Wherein, X is a column matrix containing the temperatures of (N+1) terminals, Y is a column matrix containing the SC junction temperature of a specific chip and the power loss of N power chips, and R is a (N+1)-order first transfer coefficient matrix;

[0090] Since R is a square matrix, its inverse matrix R can be calculated -1 , that is, the inverse matrix of the transfer coefficient R -1 .

[0091] As an example of this embodiment, at the three pre-selected terminals, the first transfer coefficient matrix R is derived, and the transfer coefficient inverse matrix R is calculated. -1 When the thermal coefficients under the thermal effects of different chips are obtained, the first transfer coefficient matrix R is obtained:

[0092]

[0093] That is, RY = X, and then the inverse matrix R of the first transfer coefficient matrix can be calculated -1 , which is the inverse matrix of transfer coefficients.

[0094] Step 104: placing the IGBT module in a field operating condition, measuring the current temperature of each terminal of the IGBT module, and online estimating each current temperature and the inverse matrix of the transfer coefficient to obtain the junction temperature and power loss of the IGBT module.

[0095] In this embodiment, for an IGBT module operating under field conditions, the temperature of K terminals is measured by a temperature sensor, and the inverse matrix R of the transfer coefficient is used. -1 ,Online calculation of the steady-state junction temperature of a specific chip SC and the power loss of each chip.

[0096] Optionally, step 104 specifically includes step 1041 to step 1042, and each step is specifically as follows:

[0097] Step 1041: placing the IGBT module in a field operating condition, placing a temperature sensor on each terminal, and measuring the current temperature of each terminal of the IGBT module through each temperature sensor.

[0098] In this embodiment, temperature sensors are placed on K pre-selected terminals of the IGBT module, and the terminal online temperature matrix is ​​obtained by using the measured terminal temperatures during field operation.

[0099] Step 1042: Obtain a terminal online temperature matrix according to each current temperature; perform a matrix product operation on the inverse transfer coefficient matrix and the terminal online temperature matrix to obtain the junction temperature and power loss of the IGBT module.

[0100] As an example of this embodiment, for an IGBT module operating under field conditions, temperature sensors are placed on three pre-selected terminals, and the measured terminal temperatures and the inverse transfer coefficient matrix R are used to calculate the temperature of the IGBT module. -1 , online calculation column matrix: Y = R -1 X, and obtain the steady-state junction temperature of the IGBT chip and the power loss of each chip. By looping through step 104, the junction temperature and power loss of the IGBT module can be continuously evaluated.

[0101] In the implementation of the embodiment of the present invention, several terminals of the IGBT module are selected according to the preset selection rules; wherein the number of terminals is obtained according to the number of power chips in the IGBT module; the IGBT module is subjected to a characteristic experiment, and a thermal model is established according to the thermal coefficient from a specific chip to each terminal; the thermal model is subjected to junction temperature transfer calculation to obtain an inverse matrix of transfer coefficients; the IGBT module is placed in a field operation condition, the current temperature of each terminal of the IGBT module is measured, and each current temperature and the inverse matrix of transfer coefficients are estimated online to obtain the junction temperature and power loss of the IGBT module. For the same IGBT module, the characteristic experiment under laboratory conditions only needs to be carried out once, and the online calculation of the junction temperature under field operation conditions can be realized, and the iterative calculation of the device loss does not need to be carried out in the process, and the rapid evaluation of the junction temperature can be achieved with a very small amount of calculation. The field operation online calculation only needs to measure the temperature of several terminals, and does not need to measure the electrical parameters of the IGBT, and can be electrically isolated from the main circuit to avoid the measurement and evaluation process being affected by the main circuit. For IGBT modules with aged solder layers, since the heat flow path from the chip to each terminal has little to do with the solder layer, the accuracy of the junction temperature assessment will not be affected by aging, thereby improving the accuracy of the assessment data.

[0102] Embodiment 2

[0103] Accordingly, see Figure 6 , Figure 6 1 is a schematic diagram of the structure of a second embodiment of an evaluation system for junction temperature and power loss of an IGBT module provided by the present invention. Figure 6 As shown, a selection unit 601, a characteristic experiment unit 602, a matrix calculation unit 603 and an online estimation unit 604;

[0104] The selection unit 601 is used to select a number of terminals of the IGBT module according to a preset selection rule; wherein the number of terminals is obtained according to the number of power chips in the IGBT module;

[0105] Optionally, a selection rule is preset, specifically: the thermal effect generated by the power loss of each power chip affects each terminal to a different extent, ensuring that the thermal characteristics of each terminal are different.

[0106] Optionally, the number of terminals is obtained according to the number of power chips in the IGBT module, specifically: the number of all power chips in the IGBT module is counted to obtain a first number; and 1 is added to the first number to obtain the number of terminals.

[0107] The characteristic experiment unit 602 is used to perform characteristic experiments on the IGBT module and establish a thermal model based on the thermal coefficient from the specific chip to each terminal;

[0108] Optionally, the IGBT module is subjected to a characteristic experiment, and a thermal model is established based on the thermal coefficient from a specific chip to each terminal, specifically:

[0109] Perform a characteristic experiment on the current power chip in the IGBT module to obtain the power loss of the current power chip, and measure the current first temperature data; wherein, during the characteristic experiment, only one power chip generates power loss at the same time; calculate the current first temperature data and the power loss of the current power chip to obtain the thermal coefficient from the specific chip to each terminal under the thermal effect of the current power chip; wherein, the current first temperature data includes the current first junction temperature of the specific chip and the current first temperature of each terminal; perform a characteristic experiment on all power chips in the IGBT module, calculate the thermal coefficient from the specific chip to each terminal under the thermal effect of each power chip, obtain all the thermal coefficients, and construct a thermal model based on all the thermal coefficients.

[0110] Optionally, a characteristic experiment is performed on the current power chip in the IGBT module to obtain the power loss of the current power chip, specifically: according to the characteristic experiment circuit, the IGBT module is connected to a preset position; the preset switch is closed, and the gate driver applies a high-level signal to turn on the IGBT module, and the DC power supply operates in a current source mode; when the current flowing through the current power chip reaches a preset current value, the voltage across the current power chip is measured to obtain the current voltage; the current voltage and the preset current value are numerically calculated to obtain the power loss of the current power chip.

[0111] Optionally, the current first temperature data and the power loss of the current power chip are calculated to obtain a thermal coefficient from a specific chip to each terminal under the thermal effect of the current power chip, specifically:

[0112] …;

[0113] Among them, r kn is the thermal coefficient of terminal k, T tk is the current first temperature of terminal k, P n is the power loss of power chip n, T jis the current first junction temperature of a specific chip, n is the number of power chips, indicating power chip n, and k is the number of terminals, indicating terminal k.

[0114] The matrix calculation unit 603 is used to perform junction temperature transfer calculation on the thermal model to obtain an inverse matrix of transfer coefficients;

[0115] The thermal model is used to calculate the junction temperature transfer and obtain the inverse matrix of the transfer coefficient, which is:

[0116] Thermal model, specifically:

[0117] RY=X

[0118] Wherein, X is a column matrix of the temperature of each terminal, Y is a column matrix of the junction temperature of a specific chip and the power loss of a power chip, and R is a first transfer coefficient matrix; wherein the first transfer coefficient matrix is ​​obtained according to all thermal coefficients;

[0119] According to the thermal model, the inverse matrix corresponding to the first transfer coefficient matrix is ​​calculated to obtain the transfer coefficient inverse matrix.

[0120] The online estimation unit 604 is used to place the IGBT module in a field operating condition, measure the current temperature of each terminal of the IGBT module, and perform online estimation of each current temperature and the inverse matrix of the transfer coefficient to obtain the junction temperature and power loss of the IGBT module.

[0121] Optionally, the IGBT module is placed in field operating conditions and the current temperature of each terminal of the IGBT module is measured. Specifically, the IGBT module is placed in field operating conditions, a temperature sensor is placed on each terminal, and the current temperature of each terminal of the IGBT module is measured by each temperature sensor.

[0122] Optionally, each current temperature and the inverse matrix of the transfer coefficient are estimated online to obtain the junction temperature and power loss of the IGBT module, specifically: according to each current temperature, the terminal online temperature matrix is ​​obtained; the inverse matrix of the transfer coefficient and the terminal online temperature matrix are matrix multiplied to obtain the junction temperature and power loss of the IGBT module.

[0123] By implementing the embodiment of the present invention, the junction temperature and power loss of the IGBT module are quickly evaluated. First, a thermal relationship model between the chip and different terminals or leads is established through an offline characterization experiment. Then, the temperatures of multiple terminals are measured, and the established model is used to online evaluate the junction temperature and power loss of the IGBT module in operation. Compared with the prior art, the advantages of the present invention are as follows: (1) For the same IGBT module, the characteristic experiment under laboratory conditions only needs to be carried out once, and the online calculation of the junction temperature under field conditions can be realized, and no iterative calculation of the device loss is required during the process, so that a rapid evaluation of the junction temperature can be achieved with a very small amount of calculation. (2) During field operation, only the temperature of a few terminals needs to be measured, and the electrical parameters of the IGBT do not need to be measured, so that electrical isolation can be achieved from the main circuit. (3) For IGBT modules with aged solder layers, since the heat flow path from the chip to each terminal has little to do with the solder layer, the accuracy of the junction temperature evaluation will not be affected by aging.

[0124] The above-mentioned system for evaluating the junction temperature and power loss of an IGBT module can implement the above-mentioned method embodiment of an evaluation method for the junction temperature and power loss of an IGBT module. The optional items in the above-mentioned method embodiment are also applicable to this embodiment and will not be described in detail here. The rest of the contents of the embodiment of this application can refer to the contents of the above-mentioned method embodiment, and will not be repeated in this embodiment.

[0125] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for evaluating junction temperature and power loss of an IGBT module, characterized in that: include: According to a preset selection rule, a number of terminals of the IGBT module are selected; wherein the number of the terminals is obtained by counting the number of all power chips in the IGBT module to obtain a first number, and then adding 1 to the first number; Performing a characteristic experiment on the current power chip in the IGBT module to obtain the power loss of the current power chip and measuring the current first temperature data; wherein, during the characteristic experiment, only one power chip generates power loss at the same time; Calculate the current first temperature data and the power loss of the current power chip to obtain a thermal coefficient from the specific chip to each of the terminals under the thermal effect of the current power chip; wherein the current first temperature data includes the current first junction temperature of the specific chip and the current first temperature of each of the terminals; By performing the characteristic experiment on all power chips of the IGBT module, the thermal coefficient from the specific chip to each terminal under the thermal effect of each power chip is calculated to obtain all thermal coefficients, and a thermal model is constructed according to all thermal coefficients; Performing junction temperature transfer calculation on the thermal model, deriving a transfer coefficient matrix from the junction temperature of a specific chip to the temperature of each terminal according to the thermal model, and calculating its inverse matrix to obtain an inverse transfer coefficient matrix; The IGBT module is placed in a field operating condition, the current temperature of each terminal of the IGBT module is measured, and each current temperature and the inverse matrix of the transfer coefficient are estimated online to obtain the junction temperature and power loss of the IGBT module.

2. The method for evaluating junction temperature and power loss of an IGBT module according to claim 1, wherein: The current power chip in the IGBT module is subjected to the characteristic experiment to obtain the power loss of the current power chip, specifically: According to the characteristic experimental circuit, the IGBT module is connected to a preset position; The preset switch is closed, the gate driver applies a high level signal, the IGBT module is turned on, and the DC power supply operates in a current source mode; When the current flowing through the current power chip reaches a preset current value, measuring the voltage across the current power chip to obtain the current voltage; The current voltage and the preset current value are numerically calculated to obtain the current power loss of the power chip.

3. The method for evaluating junction temperature and power loss of an IGBT module according to claim 1, wherein: The current first temperature data and the current power loss of the power chip are calculated to obtain the thermal coefficient from the specific chip to each of the terminals under the thermal effect of the current power chip, specifically: Among them, r k n is the thermal coefficient of terminal k, Ttk is the current first temperature of the terminal k, Pn is the power loss of the power chip n, Tj is the current first junction temperature of the specific chip, n is the number of the power chips, representing the power chip n, k is the number of the terminals, representing the terminal k.

4. The method for evaluating junction temperature and power loss of an IGBT module according to claim 1, wherein: The thermal model is subjected to junction temperature transfer calculation to obtain an inverse matrix of transfer coefficients, specifically: The thermal model is specifically: RY=X Wherein, X is a column matrix of the temperature of each of the terminals, Y is a column matrix of the junction temperature of the specific chip and the power loss of the power chip, and R is a first transfer coefficient matrix; wherein, the first transfer coefficient matrix is ​​obtained according to all the thermal coefficients; According to the thermal model, an inverse matrix corresponding to the first transfer coefficient matrix is ​​calculated to obtain the transfer coefficient inverse matrix.

5. The method for evaluating junction temperature and power loss of an IGBT module according to claim 1, wherein: Placing the IGBT module in a field operating condition and measuring the current temperature of each of the terminals of the IGBT module is specifically as follows: The IGBT module is placed in a field operating condition, a temperature sensor is placed on each of the terminals, and the current temperature of each of the terminals of the IGBT module is measured by each of the temperature sensors.

6. The method for evaluating junction temperature and power loss of an IGBT module according to claim 1, wherein: The current temperature and the inverse matrix of the transfer coefficient are estimated online to obtain the junction temperature and power loss of the IGBT module, specifically: According to each of the current temperatures, a terminal online temperature matrix is ​​obtained; The transfer coefficient inverse matrix and the terminal online temperature matrix are subjected to a matrix product operation to obtain the junction temperature and power loss of the IGBT module.

7. The method for evaluating junction temperature and power loss of an IGBT module according to claim 1, wherein: The preset selection rules are specifically: The thermal effect generated by the power loss of each power chip affects each terminal to different degrees, ensuring that the thermal characteristics of each terminal are different.

8. An evaluation system for junction temperature and power loss of an IGBT module, characterized in that: include: Selection unit, characteristic experiment unit, matrix calculation unit and online estimation unit; The selection unit is used to select a number of terminals of the IGBT module according to a preset selection rule; wherein the number of the terminals is obtained by counting the number of all power chips in the IGBT module to obtain a first number, and then adding 1 to the first number; The characteristic experiment unit is used to perform a characteristic experiment on the current power chip in the IGBT module, obtain the power loss of the current power chip, and measure the current first temperature data; wherein, during the characteristic experiment, only one of the power chips generates power loss at the same time; Calculate the current first temperature data and the power loss of the current power chip to obtain a thermal coefficient from the specific chip to each of the terminals under the thermal effect of the current power chip; wherein the current first temperature data includes the current first junction temperature of the specific chip and the current first temperature of each of the terminals; By performing the characteristic experiment on all power chips of the IGBT module, the thermal coefficient from the specific chip to each terminal under the thermal effect of each power chip is calculated to obtain all thermal coefficients, and a thermal model is constructed according to all thermal coefficients; The matrix calculation unit is used to perform junction temperature transfer calculation on the thermal model, derive a transfer coefficient matrix from the junction temperature of a specific chip to the temperature of each terminal according to the thermal model, and calculate its inverse matrix to obtain an inverse transfer coefficient matrix; The online estimation unit is used to place the IGBT module in field operating conditions, measure the current temperature of each terminal of the IGBT module, and perform online estimation of each current temperature and the inverse matrix of the transfer coefficient to obtain the junction temperature and power loss of the IGBT module.

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