Online measurement method and system for junction temperature of silicon carbide MOSFET

Abstract

Online measurement method and system for junction temperature of SiC MOSFET, including drawing the dynamic temperature-sensitive electrical parameter value V of SiC MOSFET device at different current levels DTSEP1 、V DTSEP2 and junction temperature T j According to the dynamic temperature-sensitive electrical parameter value of the device, load current I and junction temperature T j The analytical model is constructed according to the relationship between the device dynamic temperature-sensitive electrical parameter value V DTSEP1 and V DTESP2 , load current I and junction temperature T j The analytical model and the dynamic temperature-sensitive electrical parameter V under the test condition DTSEP1 and V DTESP2 The value of is used to obtain the load current I of the device under different working conditions and determine the junction temperature of the device under online operation. The present invention can indirectly measure the junction temperature of silicon carbide MOSFET under any working condition, provide a basis for reliability research, state monitoring and health management of silicon carbide in practical applications, and help ensure the reliable operation of the power system.

Description

Technical Field

[0001] The present invention relates to a measurement method and system, and in particular to an online junction temperature measurement method and system for multiple electrical parameters of a silicon carbide MOSFET. Background Art

[0002] Power electronic devices are an important part of power electronic systems and are widely used in electric vehicles and other fields. The actual working conditions of power electronic devices are very harsh. In order to ensure their safe and stable operation, it is very necessary to study their reliability.

[0003] As a new generation of wide bandgap semiconductor devices, silicon carbide power devices have the advantages of high blocking voltage, high switching frequency and high temperature resistance compared with traditional power devices. They have broad application prospects in high power density power electronic systems, especially silicon carbide metal-oxide-semiconductor field-effect transistors (MOSFETs), which have significant application effects in small and medium capacity high-frequency converters and have attracted much attention. With the maturity of silicon carbide power devices, reliability issues in practical applications have become more and more prominent. The increase in chip temperature is one of the main causes of power electronic device failure. Therefore, real-time monitoring of the junction temperature of silicon carbide MOSFETs under actual working conditions is of great significance for its long-term reliability, status monitoring and health management.

[0004] At present, the junction temperature measurement methods of SiC MOSFET can be mainly divided into four categories: physical contact method, optical method, thermal network method and temperature sensitive electrical parameters (TSEP) method. Although the physical contact method and the optical method are simple and easy to implement, they both need to destroy or change the package structure to leave a measurement channel, which is highly invasive. In addition, in terms of the response speed of junction temperature measurement, due to the existence of the heat capacity of the contact layer of the physical contact method, the need for corresponding optical processing in the optical method, and the need for complex model calculation in the thermal network method, they are all subject to great restrictions. The temperature sensitive electrical parameter method characterizes the current device temperature by measuring the electrical parameters that change with temperature, and uses the device itself as a temperature sensor to indirectly reflect the chip temperature information on the numerical changes of some electrical parameters. In contrast, the temperature sensitive electrical parameter method only needs to measure the external electrical parameters, and does not need to change the original package structure, and can have a fast response capability at the μs level. It is currently a very promising online junction temperature measurement method.

[0005] At present, in the research on using temperature-sensitive electrical parameters to realize online junction temperature measurement of SiC MOSFET, a large number of electrical parameters have temperature-sensitive characteristics.

[0006] Traditional methods mostly use the temperature sensitivity of a single parameter for calibration measurement.

[0007] (1) Static temperature-sensitive electrical parameters of the device

[0008] The measurement conditions such as threshold voltage, transfer curve, on-resistance under small current and output curve do not meet the online operation conditions of the device, making it difficult to achieve online junction temperature measurement.

[0009] For example, although the gate internal resistance measurement method can be applied to switching conditions, the linearity and sensitivity of its calibration curve depend to a large extent on the gate metallization material, gate layout and manufacturing process, and its scope of application is limited.

[0010] (2) Many parameters during the device switching process also change with temperature, which are called dynamic temperature sensitive electrical parameters (DTSEP).

[0011] Parameters such as gate peak current, gate characteristic current, etc. that reflect the temperature-sensitive characteristics of gate internal resistance have limited scope of application.

[0012] Parameters such as the switching transient drain-source current change rate, the switching drain-source voltage change rate, and the turn-off delay change with the load current. When the load current changes, the calibration curve will also change. When measuring the junction temperature online, in addition to obtaining the temperature-sensitive electrical parameter value, the load current must also be measured to calculate the junction temperature. In actual engineering operation, the load current is usually a periodic function of time. This function is determined by many factors such as operating conditions, control strategies, and converter topologies. The measurement of load current is difficult and has low accuracy, which will cause a large deviation in the online measurement of junction temperature. For example, the prior art: CN209542769U discloses an invention patent for an online measurement device for junction temperature of a SIC MOSFET module based on opening dI_(ds) / dt.

[0013] Although there are a few traditional methods that measure junction temperature by combining multiple temperature-sensitive electrical parameters, they must be linearly related to the same related variable other than junction temperature to be applicable. This condition is not met for most dynamic temperature-sensitive electrical parameters. For example, the prior art: CN112556868B discloses a SiCMOSFET junction temperature detection method based on combined temperature-sensitive electrical parameter sensitivity enhancement. Summary of the invention

[0014] In view of the above-mentioned problems of the prior art, the present invention proposes an online junction temperature measurement method and system for multiple electrical parameters of silicon carbide MOSFET. Taking advantage of the wide application range of dynamic temperature-sensitive electrical parameters, but usually not having a linear relationship with other related variables except junction temperature, a model is constructed to combine two dynamic temperature-sensitive electrical parameter temperature characteristic curves to eliminate the influence of load current on junction temperature measurement. This avoids the difficulty and low accuracy of load current measurement in actual engineering operation, which leads to large deviations in online junction temperature measurement, because load current is a periodic function of time and is determined by multiple factors such as operating conditions, control strategy and converter topology. The effective measurement of online junction temperature of silicon carbide MOSFET is achieved, and its technical solution is as follows:

[0015] The method for measuring the junction temperature of multiple electrical parameters of silicon carbide MOSFET online is characterized by comprising the following steps:

[0016] Step 1: Draw the dynamic temperature-sensitive electrical parameter value V of the SiC MOSFET device at different current levels DTSEP1 and junction temperature T j The relationship curve of the selected dynamic temperature sensitive electrical parameter V DTSEP1 It needs to have a linear relationship with temperature, and can be a nonlinear relationship with load current);

[0017] Step 2: Draw the dynamic temperature-sensitive electrical parameter value V of the SiC MOSFET device at different current levels DTSEP2 and junction temperature T j The relationship curve of the selected dynamic temperature sensitive electrical parameter V DTSEP2 It needs to have a linear relationship with temperature, and can be a nonlinear relationship with load current);

[0018] Step 3: According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j , and build an analytical model;

[0019] Step 4: According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j The analytical model and the dynamic temperature-sensitive electrical parameter V under the test condition DTSEP1 and V DTESP2 The value of is used to obtain the load current I of the device under different working conditions;

[0020] Step 5: According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T jThe analytical model of and the load current I determine the junction temperature of the device during online operation.

[0021] The present invention also discloses an online junction temperature measurement system for multiple electrical parameters of a silicon carbide MOSFET, wherein the system comprises:

[0022] Silicon carbide MOSFET devices;

[0023] The drive module is used to provide gate drive signals to semiconductor devices. It can send out double pulse signals and periodic signals to control the device to shut down;

[0024] A main circuit for providing electrical connections to the semiconductor device so that the device can operate in a double pulse mode or a continuous switching mode;

[0025] Load module, used to change the operating conditions of semiconductor devices so that the devices can operate continuously at different current levels, including load resistance and load inductance;

[0026] The electrical parameter measurement module is used to extract relevant temperature-sensitive electrical parameters for online junction temperature calculation.

[0027] The heating module is used to provide the semiconductor device with an ambient temperature so that the junction temperature of the device rises to a set value. It includes a heating platform with a set temperature;

[0028] The heat dissipation module is used to dissipate heat from semiconductor devices.

[0029] Compared with the existing traditional method of realizing online junction temperature measurement of silicon carbide MOSFET using a single temperature-sensitive electrical parameter, the online junction temperature measurement method and system of silicon carbide MOSFET provided by the present invention have the following advantages:

[0030] It can indirectly measure the junction temperature of SiC MOSFET under any working conditions, has a wider range of applications, and the junction temperature measurement results are more accurate and more practical. In practical applications, it can effectively monitor the junction temperature of SiC MOSFET online, providing an important basis for reliability research, state monitoring and health management of SiC MOSFET in practical applications, which is of great significance to improving its economy and reliability in applications, and is conducive to ensuring the reliable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of an implementation flow of a method for measuring multiple electrical parameters of a silicon carbide MOSFET online junction temperature according to an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of an online junction temperature measurement system for multiple electrical parameters of a silicon carbide MOSFET in an embodiment of the present invention;

[0033] Figure 3 Temperature characteristic curve of maximum change rate of transient drain-source voltage when turned on in the embodiment of the present invention;

[0034] Figure 4 Temperature characteristic curve of maximum change rate of turn-on transient drain-source current in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] Junction temperature measurement is an important basis for thermal characterization, reliability research, condition monitoring and health management of power semiconductor devices, among which methods based on temperature-sensitive electrical parameters are highly anticipated. As a new generation of wide-bandgap semiconductor devices, silicon carbide MOSFET has excellent performance of high voltage, high frequency and low loss, and is gradually being widely used in aerospace, power systems and electric vehicles. The application of temperature-sensitive electrical parameters in its junction temperature measurement is also facing new challenges. The smaller on-state voltage drop and resistance of silicon carbide MOSFET, faster switching transient process and the considerable electromagnetic interference caused by it also put forward higher requirements on the measurement of related temperature-sensitive electrical parameters in terms of time resolution, accuracy and anti-interference.

[0036] In order to eliminate the deviation in online measurement of junction temperature caused by the difficulty and low accuracy of load current measurement in actual engineering operation, the present invention proposes a method for online measurement of junction temperature of silicon carbide MOSFET. Most dynamic temperature-sensitive electrical parameters change with temperature and load current, such as the switching transient drain-source voltage change rate, the switching transient drain-source current change rate and the turn-off delay, which are approximately linear with temperature, and the sensitivity of the parameter to temperature change depends on the size of the load current. The relationship between the parameter and the load current is usually nonlinear. It can be approximately expressed by formula (1) (2).

[0037] V DTSEP1 =(p0I 2 +p1I+p2)T+p3I 2 +p4I+p5 (1)

[0038] V DTSEP2 =(k0I 2 +k1I+k2)T+k3I 2 +k4I+k5 (2)

[0039] Where V DTSEP1 、V DTSEP2 are the dynamic temperature-sensitive electrical parameter values, and p0, p1, p2, p3, p4, p5, k0, k1, k2, k3, k4, and k5 are the fitting coefficients.

[0040] From the above formula, it can be seen that if the junction temperature is obtained only through a single dynamic temperature-sensitive electrical parameter, after obtaining the calibration curve, the load current needs to be obtained while measuring the temperature-sensitive parameter online to calculate the junction temperature. In actual engineering operation, the load current is usually a periodic function of time, which is determined by many factors such as working conditions, control strategy and converter topology. The measurement of load current is difficult and has low accuracy, which will lead to large deviations in the online measurement of junction temperature.

[0041] The present invention proposes an online junction temperature measurement method for multiple electrical parameters of silicon carbide MOSFET. After obtaining a calibration curve by linear regression method fitting, two dynamic temperature-sensitive electrical parameters are affected by temperature and load current. The equations are substituted into the two temperature-sensitive electrical parameters measured online to solve the equation to obtain the load current:

[0042] I 4 +bI 3 +cI 2 +dI+e=0 (3)

[0043] in

[0044] a=p0k3-k0p3

[0045] b=p0k4+p1k3-k0p4-k1p3

[0046] c=p0(k5-V DTSEP2 )+p1k4+p2k3-k0(p5-V DTESP1 )-k1p4-k2p3

[0047] d=p1(k5-V DTSEP2 )+p2k4-k1(p5-V DTESP1 )-k2p4

[0048] e=p2(k5-V DTSEP2 )-k2(p5-V DTESP1 )

[0049] Substituting the load current result into equation (1) or equation (2) to solve the temperature value at this time eliminates the difficulty and low precision of online load current measurement, which leads to large deviation in online measurement of junction temperature. In addition, because dynamic temperature-sensitive electrical parameters such as the switch drain-source voltage change rate and the switch drain current change rate are applicable to the turn-on process of all devices, the method proposed in the present invention has a wide range of applications.

[0050] In practical applications, the method for online measurement of junction temperature proposed by the present invention is as follows:

[0051] The method for measuring the junction temperature of multiple electrical parameters of silicon carbide MOSFET online is characterized by comprising the following steps:

[0052] 1. A method for measuring the junction temperature of multiple electrical parameters of a silicon carbide MOSFET online, characterized by comprising the following steps:

[0053] Step 1: Draw the dynamic temperature-sensitive electrical parameter value V of the SiC MOSFET device at different current levels DTSEP1 and junction temperature T j The relationship curve of the selected dynamic temperature sensitive electrical parameter V DTSEP1 It needs to have a linear relationship with temperature, and can be a nonlinear relationship with load current);

[0054] (1) Configure the driving resistance R of the driving module G , driving forward voltage V GH And the negative driving voltage V GL and the SiC MOSFET device bus voltage V DS ;

[0055] (2) Setting the driving module to output a double pulse waveform and adjusting the pulse width to turn on the silicon carbide MOSFET device at a certain current level;

[0056] (3) Configure the heating module, fix the SiC MOSFET device on the heating platform, apply the ambient temperature through the heating platform to raise the junction temperature of the SiC MOSFET device to the specified temperature, and collect V DTSEP1 The junction temperature T at this current level is plotted. j and dynamic temperature sensitive electrical parameter value V DTSEP1 The change relationship curve of

[0057] (4) Continue to increase the pulse width of the driving module, increase the turn-on current level of the silicon carbide MOSFET device, repeat step (3), and plot the junction temperature Tj and the dynamic temperature-sensitive electrical parameter value V at at least 4 different current levels. DTSEP1 The change relationship curve.

[0058] Step 2: Draw the dynamic temperature-sensitive electrical parameter value V of the SiC MOSFET device at different current levels DTSEP2 and junction temperature T j The relationship curve of the selected dynamic temperature sensitive electrical parameter V DTSEP2 It needs to have a linear relationship with temperature, and can be a nonlinear relationship with load current);

[0059] (1) Maintain the bus voltage settings of the driver module and the silicon carbide MOSFET device in step 1;

[0060] (2) setting the same double pulse waveform pulse width as in step 1, so that the silicon carbide MOSFET device is turned on at the corresponding current level;

[0061] (3) Configure the heating module, apply the ambient temperature through the heating platform to raise the junction temperature of the silicon carbide MOSFET device to the specified temperature, and collect the dynamic temperature-sensitive electrical parameter value V during the heating process DTSEP2 The junction temperature T at this current level is plotted. j and dynamic temperature sensitive electrical parameter value V DTSEP2 The change relationship curve of

[0062] (4) Continue to increase the pulse width of the driving module, increase the device turn-on current level, repeat step (3), and plot the junction temperature T at at least 4 different current levels. j and dynamic temperature sensitive electrical parameter value V DTSEP2 The change relationship curve.

[0063] Step 3: According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j , and build an analytical model;

[0064] (1) Dynamic temperature-sensitive electrical parameter value V DTSEP1 It changes with temperature and is approximately linear. The sensitivity of temperature change depends on the load current I of the silicon carbide MOSFET device and the dynamic temperature sensitive electrical parameter value V DTSEP1 The relationship with the load current is nonlinear, and the dynamic temperature-sensitive electrical parameter value V is approximated by a quadratic function. DTSEP1 The relationship between the change of load current I and the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 , load current I and junction temperature T j The model can be approximately expressed by formula (1);

[0065] V DTSEP1 =(p0I 2 +p1I+p2)T j +p3I 2 +p4I+p5 (1)

[0066] Where V DTSEP1 is the dynamic temperature-sensitive electrical parameter value, and p0, p1, p2, p3, p4, and p5 are fitting coefficients.

[0067] (2) Dynamic temperature-sensitive electrical parameter value V DTSEP2 It changes with temperature and is approximately linear. The sensitivity of temperature change depends on the load current I of the silicon carbide MOSFET device and the dynamic temperature sensitive electrical parameter value V DTSEP2 The relationship with the load current is nonlinear, and the dynamic temperature-sensitive electrical parameter value V is approximated by a quadratic function. DTSEP2 The relationship between the change of load current I and the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET deviceDTSEP2 , load current I and junction temperature T j The model can be approximately expressed by formula (2);

[0068] V DTSEP2 =(k0I 2 +k1I+k2)T j +k3I 2 +k4I+k5 (2)

[0069] Where V DTSEP2 is the dynamic temperature-sensitive electrical parameter value, k0, k1, k2, k3, k4, k5 are the fitting coefficients.

[0070] (3) According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j The relationship between the dynamic temperature-sensitive electrical parameter values ​​V and DTSEP1 And the dynamic temperature sensitive electrical parameter value V DTSEP2 The junction temperature T of SiC MOSFET device j The analytical model of the load current I is shown in equations (1) and (2)

[0071] V DTSEP1 =(p0I 2 +p1I+p2)T j +p3I 2 +p4I+p5 (1)

[0072] V DTSEP2 =(k0I 2 +k1I+k2)T j +k3I 2 +k4I+k5 (2)

[0073] Where V DTSEP1 、V DTSEP2 are the dynamic temperature-sensitive electrical parameter values, and p0, p1, p2, p3, p4, p5, k0, k1, k2, k3, k4, and k5 are the coefficients fitted by the linear regression method.

[0074] Step 4: According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j The analytical model and the dynamic temperature-sensitive electrical parameter V under the test condition DTSEP1 and V DTESP2 The value of is used to obtain the load current I of the device under different working conditions;

[0075] (1) configuring a driving module to output continuous pulses so that the SiC MOSFET device operates in a continuous switching mode, adjusting the frequency and duty cycle, and continuously changing the operating conditions of the SiC MOSFET device;

[0076] (2) Measure the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device under different working conditions, as the device self-heats to reach the temperature equilibrium state. DTSEP1 and V DTESP2 ;

[0077] (3) Comparing the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j The analytical model and the dynamic temperature-sensitive electrical parameter V under the test condition DTSEP1 and V DTESP2 The value of V is used for mathematical calculations, and the two dynamic temperature-sensitive electrical parameters affected by temperature and load current are combined and substituted into the two dynamic temperature-sensitive electrical parameter values ​​V of the silicon carbide MOSFET device measured under online conditions. DTSEP1 and V DTESP2 , solve the equation to obtain the load current:

[0078] I 4 +bI 3 +cI 2 +dI+e=0

[0079] in

[0080] a=p0k3-k0p3

[0081] b=p0k4+p1k3-k0p4-k1p3

[0082] c=p0(k5-V DTSEP2 )+p1k4+p2k3-k0(p5-V DTESP1 )-k1p4-k2p3.

[0083] d=p1(k5-V DTSEP2 )+p2k4-k1(p5-V DTESP1 )-k2p4

[0084] e=p2(k5-V DTSEP2 )-k2(p5-V DTESP1 )

[0085] Step 5: According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T jThe analytical model of and the load current I determine the junction temperature of the device in online operation:

[0086] According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j Substitute the analytical model of the load current I into formula (1) or formula (2) to determine the junction temperature of the device when it is operating online.

[0087] See attached Figure 2 As shown, the present invention discloses an online junction temperature measurement system for multiple electrical parameters of a silicon carbide MOSFET, characterized in that the system comprises:

[0088] Silicon carbide MOSFET devices;

[0089] The driving module is used to provide gate driving signals to semiconductor devices; it can send out double pulse signals and periodic signals to control device shutdown;

[0090] A main circuit for providing electrical connections to the semiconductor device so that the device can operate in a double pulse mode or a continuous switching mode;

[0091] Load module, used to change the operating conditions of semiconductor devices so that the devices can operate continuously at different current levels, including load resistance and load inductance;

[0092] Electrical parameter measurement module, used to extract relevant temperature-sensitive electrical parameters for online junction temperature calculation;

[0093] A heating module is used to provide an ambient temperature to the semiconductor device so that the junction temperature of the device rises to a set value, including a heating platform with a settable temperature;

[0094] The heat dissipation module is used to dissipate heat from semiconductor devices.

[0095] Embodiment 1:

[0096] Figure 1 This is a schematic diagram of the implementation process of a method for measuring the junction temperature of multiple electrical parameters of a silicon carbide MOSFET in an embodiment of the present invention. As shown in the figure, the maximum change rate of the turn-on transient drain-source voltage and the maximum change rate of the turn-on transient drain-source voltage are selected as temperature-sensitive electrical parameters, and the temperature characteristics of the two are combined to monitor the junction temperature online. The specific steps are as follows:

[0097] Step 1: Draw the maximum change rate of the transient drain-source voltage V of the dynamic temperature-sensitive electrical parameters of the SiC MOSFET device at different current levels DTSEP1 and junction temperature T j The relationship curve.

[0098] (1) Configure the driving resistance R of the driving module G , driving forward voltage V GH And the negative driving voltage V GL and the SiC MOSFET device bus voltage V DS

[0099] (2) Setting the drive module to output a double pulse waveform and adjusting the pulse width to turn on the silicon carbide MOSFET device at I = 3A;

[0100] (3) Configure the heating module, fix the specimen on the heating table, apply ambient temperature through the heating table to raise the junction temperature of the device to 130°C, and collect the maximum change rate V of the turn-on transient drain-source voltage during the heating process. DTSEP1 The junction temperature T at this current level is plotted. j Maximum change rate of drain-source voltage during turn-on transient V DTSEP1 The change relationship curve of

[0101] (4) Continue to increase the pulse width of the driving module, increase the device turn-on current level, repeat step (3), and plot the junction temperature Tj and V at at least 4 different current levels. DTSEP1 The change relationship curve of Figure 3 .

[0102] Step 2: Draw the maximum change rate of the transient drain-source current V of the dynamic temperature-sensitive electrical parameters of the SiC MOSFET device at different current levels DTSEP2 and junction temperature T j The relationship curve:

[0103] (1) Maintain the bus voltage settings of the driver module and the silicon carbide MOSFET device in step 1;

[0104] (2) setting the same double pulse waveform pulse width as in step 1, so that the silicon carbide MOSFET device is turned on at the corresponding current level;

[0105] (3) Configure a heating module and apply ambient temperature through the heating platform to raise the junction temperature of the SiC MOSFET device to 130°C. Collect the maximum change rate of the transient drain-source current V during the heating process. DTSEP2 The junction temperature T at this current level is plotted. j Maximum change rate of drain-source current during turn-on transient V DTSEP2 The change relationship curve of

[0106] (4) Continue to increase the pulse width of the driving module, increase the turn-on current level of the SiC MOSFET device, repeat step (3), and plot the junction temperature T at at least 4 different current levels. j Maximum change rate of drain-source current during turn-on transient V DTSEP2The change relationship curve.

[0107] Step 3: Turn on the maximum change rate of transient drain-source voltage V according to the dynamic temperature-sensitive electrical parameters of the silicon carbide MOSFET device DTSEP1 and the maximum change rate of drain-source voltage during turn-on transient V DTESP2 , load current I and junction temperature T j , and build an analytical model:

[0108] (1) Maximum change rate of drain-source voltage during turn-on V DTSEP1 It increases with temperature and is approximately linear. The sensitivity to temperature change depends on the size of the device load current I. The maximum change rate of the transient drain-source voltage V can be approximately expressed by a quadratic function. DTSEP1 Relationship with the change of load current I.

[0109] (2) Maximum change rate of drain-source current during turn-on V DTSEP2 It increases with temperature and is approximately linear. The sensitivity to temperature change depends on the size of the device load current I. The maximum change rate of the transient drain-source current V can be approximately expressed by a quadratic function. DTSEP2 Relationship with the change of load current I.

[0110] (3) The linear regression method is used to fit the maximum change rate of the transient drain-source voltage V DTSEP1 and the maximum change rate of drain-source current during turn-on transient V DTSEP2 The junction temperature T j The relationship between the load current I and the load current I is shown in (1) and (2)

[0111] V DTSEP1 =(p0I 2 +p1I+p2)T j +p3I 2 +p4I+p5 (1)

[0112] V DTSEP2 =(k0I 2 +k1I+k2)T j +k3I 2 +k4I+k5 (2)

[0113] Where V DTSEP1 、V DTSEP2 is the dynamic temperature-sensitive electrical parameter value, p0, p1, p2, p3, p4, p5, k0, k1, k2, k3, k4, k5 are the coefficients obtained by linear regression fitting of the experimental data obtained in steps 1 and 2:

[0114] p=[4.97E-06 1.69E-05 9.03E-05 -0.002049 0.05296 0.1799];

[0115] k=[-2.35E-06 3.23E-05 0.0001107 0.00019 -0.0035 0.07993].

[0116] Step 4: Turn on the maximum change rate of transient drain-source voltage V according to the dynamic temperature-sensitive electrical parameters of the silicon carbide MOSFET device DTSEP1 and the maximum change rate of drain-source current during turn-on transient V DTESP2 , load current I and junction temperature T j The analytical model and the dynamic temperature-sensitive electrical parameter V under the test condition DTSEP1 and V DTESP2 The value of the load current I of the device under different working conditions is obtained:

[0117] (1) Configure the drive module to output continuous pulses so that the SiC MOSFET device operates in a continuous switching mode, and adjust the frequency f = 100 kHz and the duty cycle D = 0.5.

[0118] (2) Measure the maximum change rate of the drain-source voltage V of the SiC MOSFET device when it is turned on due to the self-heating of the device reaching the temperature equilibrium state under different working conditions. DTSEP1 and the maximum change rate of drain-source current during turn-on transient V DTESP2

[0119] (3) Comparison of the maximum change rate of drain-source voltage when the SiC MOSFET device is turned on V DTSEP1 and the maximum change rate of drain-source current during turn-on transient V DTESP2 Perform mathematical operations with the corresponding analytical model, combine the equations of the two dynamic temperature-sensitive electrical parameters affected by temperature and load current, substitute the two temperature-sensitive electrical parameters measured online to solve the equation and obtain the load current:

[0120] I 4 +bI 3 +cI 2 +dI+e=0

[0121] in

[0122] a=p0k3-k0p3

[0123] b=p0k4+p1k3-k0p4-k1p3

[0124] c=p0(k5-V DTSEP2 )+p1k4+p2k3-k0(p5-V DTESP1)-k1p4-k2p3

[0125] d=p1(k5-V DTSEP2 )+p2k4-k1(p5-V DTESP1 )-k2p4

[0126] e=p2(k5-V DTSEP2 )-k2(p5-V DTESP1 )

[0127] The solution is I=8.283398A.

[0128] Step 5: Turn on the transient drain-source voltage maximum change rate V according to the dynamic temperature-sensitive electrical parameters of the silicon carbide MOSFET device DTSEP1 and the maximum change rate of drain-source current during turn-on transient V DTESP2 , load current I and junction temperature T j The analytical model of and the load current I determine the junction temperature of the device in online operation. :

[0129] According to the load current I and the dynamic temperature-sensitive electrical parameters of the SiC MOSFET device, the maximum change rate of the transient drain-source voltage V is DTSEP1 , load current I and junction temperature Tj are substituted into formula (1) or formula (2) to obtain the device junction temperature T = 81.08553°C.

[0130] Taking advantage of the wide applicability of dynamic temperature-sensitive electrical parameters, effective measurement of the online junction temperature of silicon carbide MOSFET is achieved.

[0131] The method and system for measuring the junction temperature of multiple electrical parameters of silicon carbide MOSFET proposed in the present invention have higher accuracy. Under the junction temperature measurement method proposed in the present invention, two dynamic temperature-sensitive electrical parameter temperature characteristic curves are combined to eliminate the influence of load current on junction temperature measurement. This avoids the difficulty and low accuracy of load current measurement in actual engineering operation, which leads to large deviations in online junction temperature measurement because load current is a periodic function of time and is determined by multiple factors such as working conditions, control strategy and converter topology.

[0132] The online junction temperature measurement method and system for multiple electrical parameters of multi-SiC MOSFET proposed in the present invention have a wider scope of application. Under the online junction temperature measurement method proposed in the present invention, the junction temperature is estimated by combining the temperature characteristics of two dynamic temperature-sensitive electrical parameters, which is applicable to all SiC MOSFET devices and is not affected by the device manufacturer, batch, and manufacturing process; and the requirements for temperature-sensitive electrical parameters are lower, and the two parameters are no longer required to have a linear relationship with other related variables except the junction temperature, thereby having a wider scope of application.

[0133] The online junction temperature measurement method and system for multiple electrical parameters of silicon carbide MOSFET proposed in the present invention have stronger practicality. Under the online junction temperature measurement method proposed in the present invention, the measurement of online electrical parameters does not require the measurement of load current, the parameter extraction circuit is easier to implement, the operation is simple and the cost is low.

[0134] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. Online measurement method for junction temperature of silicon carbide MOSFET. This method is an online junction temperature measurement method for multiple electrical parameters of silicon carbide MOSFET, and its characteristics are: The steps include: Step 1: Draw the dynamic temperature-sensitive electrical parameter value V of the SiC MOSFET device at different current levels DTSEP1 and junction temperature T j The relationship curve of Step 2: Draw the dynamic temperature-sensitive electrical parameter value V of the SiC MOSFET device at different current levels DTSEP2 and junction temperature T j The relationship curve of Step 3: According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j , and build an analytical model: (1) Dynamic temperature-sensitive electrical parameter value V DTSEP1 It changes with temperature and is approximately linear. The sensitivity of temperature change depends on the load current I of the silicon carbide MOSFET device and the dynamic temperature sensitive electrical parameter value V DTSEP1 The relationship with the load current is nonlinear, and the dynamic temperature-sensitive electrical parameter value V is approximated by a quadratic function. DTSEP1 The relationship between the change of load current I and the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 , load current I and junction temperature T j The model can be approximately expressed by formula (1); V DTSEP1 =(p0I 2 +p1 I+p2)T j +p3I 2 +p4I+p5 (1) Where V DTSEP1 is the dynamic temperature-sensitive electrical parameter value, p0, p1, p2, p3, p4, p5 are fitting coefficients; (2) Dynamic temperature-sensitive electrical parameter value V DTSEP2 It changes with temperature and is approximately linear. The sensitivity of temperature change depends on the load current I of the silicon carbide MOSFET device and the dynamic temperature sensitive electrical parameter value V DTSEP2 The relationship with the load current is nonlinear, and the dynamic temperature-sensitive electrical parameter value V is approximated by a quadratic function. DTSEP2 The relationship between the change of load current I and the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP2 , load current I and junction temperature T j The model can be approximately expressed by formula (2); V DTSEP2 =(k0I 2 +k1 I+k2)T j +k3I 2 +k4I+k5 (2) Where V DTSEP2 is the dynamic temperature-sensitive electrical parameter value, k0, k1, k2, k3, k4, k5 are fitting coefficients; (3) According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j The relationship between the dynamic temperature-sensitive electrical parameter values ​​V and DTSEP1 And the dynamic temperature sensitive electrical parameter value V DTSEP2 The junction temperature T of SiC MOSFET device j The analytical model of the load current I is shown in equations (1) and (2); Step 4: According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j The analytical model and the dynamic temperature-sensitive electrical parameter V under the test condition DTSEP1 and V DTESP2 The value of is used to obtain the load current I of the device under different working conditions; Step 5: According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j The analytical model of and the load current I determine the junction temperature of the device during online operation.

2. The method for online measurement of junction temperature of silicon carbide MOSFET according to claim 1, characterized in that: said step 1 further comprises the following contents: (1) Selected dynamic temperature-sensitive electrical parameter V DTSEP1 It needs to have a linear relationship with temperature, and can have a nonlinear relationship with load current; (2) Configure the driving resistance R of the driving module G , driving forward voltage V GH And the negative driving voltage V GL and the SiC MOSFET device bus voltage V DS ; (3) Setting the driving module to output a double pulse waveform and adjusting the pulse width to turn on the silicon carbide MOSFET device at a certain current level; (4) Configure a heating module, fix the SiC MOSFET device on a heating platform, apply ambient temperature through the heating platform to raise the junction temperature of the SiC MOSFET device to a specified temperature, and collect V DTSEP1 The junction temperature T at this current level is plotted. j and dynamic temperature sensitive electrical parameter value V DTSEP1 The change relationship curve of (5) Continue to increase the pulse width of the driving module, increase the turn-on current level of the silicon carbide MOSFET device, repeat step (3), and plot the junction temperature Tj and the dynamic temperature-sensitive electrical parameter value V at at least 4 different current levels. DTSEP1 The change relationship curve.

3. The method for online measurement of junction temperature of silicon carbide MOSFET according to claim 2, characterized in that: said step 2 further comprises the following contents: (1) Selected dynamic temperature-sensitive electrical parameter V DTSEP2 It needs to have a linear relationship with temperature, and can have a nonlinear relationship with load current; (2) Maintaining the bus voltage settings of the driver module and the silicon carbide MOSFET device in step 1; (3) setting the same double pulse waveform pulse width as in step 1, so that the silicon carbide MOSFET device is turned on at the corresponding current level; (4) Configure the heating module, apply the ambient temperature through the heating platform to raise the junction temperature of the silicon carbide MOSFET device to the specified temperature, and collect the dynamic temperature-sensitive electrical parameter value V during the heating process DTSEP2 The junction temperature T at this current level is plotted. j and dynamic temperature sensitive electrical parameter value V DTSEP2 The change relationship curve of (5) Continue to increase the pulse width of the driving module, increase the device turn-on current level, repeat step (3) in step 2, and plot the junction temperature T at at least 4 different current levels. j and dynamic temperature sensitive electrical parameter value V DTSEP2 The change relationship curve.

4. The method for online measurement of junction temperature of silicon carbide MOSFET according to claim 3, characterized in that: The step 4 further includes the following contents: (1) configuring a driving module to output continuous pulses so that the SiC MOSFET device operates in a continuous switching mode, adjusting the frequency and duty cycle, and continuously changing the operating conditions of the SiC MOSFET device; (2) Measure the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device under different working conditions, as the device self-heats to reach the temperature equilibrium state. DTSEP1 and V DTESP2 ; (3) Comparing the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current I and junction temperature T j The analytical model and the dynamic temperature-sensitive electrical parameter V under the test condition DTSEP1 and V DTESP2 The value of V is used for mathematical calculations, and the two dynamic temperature-sensitive electrical parameters affected by temperature and load current are combined and substituted into the two dynamic temperature-sensitive electrical parameter values ​​V of the silicon carbide MOSFET device measured under online conditions. DTSEP1 and V DTESP2 , solve the equation to obtain the load current: al 4 +bl 3 +cl 2 +dl+e=0 in: a=p0k3-k0p3 b=p0k4+p1k3-k0p4-k1p3 c=p0(k5-V DTSEP2 )+p1k4+p2k3-k0(p5-V DTESP1 )-k1p4-k2p3 d=p1(k5-V DTSEP2 )+p2k4-k1(p5-V DTESP1 )-k2p4 e=p2( k 5-V DTSEP2 )-k2(p5-V DTESP1 )。 5. The method for online measurement of junction temperature of silicon carbide MOSFET according to claim 1, characterized in that: said step 5 further comprises the following contents: According to the dynamic temperature-sensitive electrical parameter value V of the silicon carbide MOSFET device DTSEP1 and V DTESP2 , load current l and junction temperature T j Substitute the analytical model of the load current l into formula (1) or formula (2) to determine the junction temperature of the device when it is running online.

6. An online junction temperature measurement system for multiple electrical parameters of a silicon carbide MOSFET, the system comprising the online junction temperature measurement method for a silicon carbide MOSFET according to any one of claims 1 to 5, characterized in that: The system comprises: Silicon carbide MOSFET devices; The driving module is used to provide gate driving signals to semiconductor devices; it can send out double pulse signals and periodic signals to control device shutdown; A main circuit for providing electrical connections to the semiconductor device so that the device can operate in a double pulse mode or a continuous switching mode; Load module, used to change the operating conditions of semiconductor devices so that the devices can operate continuously at different current levels, including load resistance and load inductance; An electrical parameter measurement module is used to extract relevant temperature-sensitive electrical parameters for online junction temperature calculation; a heating module is used to provide an ambient temperature to the semiconductor device so that the device junction temperature rises to a set value, including a heating platform that can set the temperature; The heat dissipation module is used to dissipate heat from semiconductor devices.

Images