A method and device for estimating the junction temperature of an IGBT

Abstract

The present application discloses a method and device for estimating the IGBT junction temperature. The method includes: after obtaining the maximum junction temperature curve and the average junction temperature curve of the target IGBT, according to the maximum junction temperature curve and the average junction temperature curve of the target IGBT, the maximum junction temperature profile curve of the target IGBT is obtained in real time, so that the junction temperature of the target IGBT can be estimated in real time according to the maximum junction temperature profile curve of the target IGBT, and an estimation result is obtained. It can be seen that according to the characteristics that the maximum junction temperature curve has large fluctuations but can reflect the maximum value, and the average junction temperature curve has gentle fluctuations but cannot reflect the maximum value, the present application extracts the maximum junction temperature profile curve of the target IGBT in real time. This profile curve is more stable, can represent the maximum junction temperature of the target IGBT in real time, and when used to estimate the junction temperature of the target IGBT in real time, can effectively reduce the fluctuations of the maximum junction temperature. When performing derating protection for excessive junction temperature, the fluctuations of the power output can be effectively reduced, ensuring the safe and reliable operation of the IGBT.

Description

Technical Field

[0001] This application relates to the field of electronic technologies, and in particular, to a method and device for estimating the junction temperature of an IGBT. Background Art

[0002] An insulated gate bipolar transistor (IGBT for short) is a composite fully controlled voltage-driven power semiconductor device composed of a bipolar junction transistor (BJT for short) and a metal-oxide-semiconductor field-effect transistor (MOS for short). It combines the advantages of a field-effect transistor and a giant transistor, has characteristics such as fast switching speed, high voltage resistance, and large current, and is suitable for application in high-power power electronic conversion devices. It has been widely used in fields such as electric vehicles and rail transit.

[0003] The junction temperature of an IGBT is an important factor for evaluating the safety and lifespan of the IGBT. To ensure that the IGBT can operate safely and reliably in these high-power application scenarios for a long time, it is necessary to estimate the junction temperature of the IGBT online. The IGBT itself has a limit on the maximum junction temperature. When the junction temperature of the IGBT exceeds this limit, the IGBT is at risk of reduced lifespan or even burnout. If the junction temperature can be estimated in real time, measures can be taken in advance for derating protection, thereby ensuring the safe and reliable operation of the IGBT.

[0004] However, currently, most products do not estimate the junction temperature of the IGBT and rely only on experiments to ensure, which cannot guarantee the safe and reliable operation of the IGBT. Even for products that perform junction temperature estimation, most also use the maximum junction temperature for estimation. That is, when an IGBT module usually contains three bridge arms and each bridge arm contains two IGBTs, it is necessary to estimate the junction temperatures of 6 IGBTs simultaneously. To obtain the maximum junction temperature of the 6 IGBTs, it is usually necessary to compare the estimated junction temperatures of the 6 channels to obtain the maximum junction temperature curve of the IGBT. However, the maximum junction temperature obtained by this method fluctuates greatly. Using this maximum junction temperature curve for derating protection usually causes sudden changes or jitters in the system power, thereby affecting the power output stability of the product. For example, in a vehicle, the adverse effect is unstable torque output and vehicle jitter. Summary of the Invention

[0005] The main purpose of the embodiments of this application is to provide a method and device for estimating the junction temperature of an IGBT, which can extract the maximum junction temperature profile curve of the IGBT in real time to characterize the maximum junction temperature of the IGBT in real time, and will not cause the estimated junction temperature to be too high or too low.

[0006] In the first aspect of the present application, a method for estimating the IGBT junction temperature is proposed, including:

[0007] Obtain the highest junction temperature curve of the target IGBT;

[0008] Obtain the average junction temperature curve of the target IGBT;

[0009] According to the highest junction temperature curve and the average junction temperature curve of the target IGBT, obtain the highest junction temperature profile curve of the target IGBT;

[0010] According to the highest junction temperature profile curve of the target IGBT, estimate the junction temperature of the target IGBT in real time to obtain an estimation result.

[0011] In an optional implementation manner, the obtaining the highest junction temperature curve of the target IGBT includes:

[0012] Obtain six-way junction temperature signals of the target IGBT;

[0013] According to the six-way junction temperature signals of the target IGBT, obtain the highest junction temperature signal of the highest junction temperature curve of the target IGBT.

[0014] In an optional implementation manner, the obtaining the highest junction temperature signal of the highest junction temperature curve of the target IGBT according to the six-way junction temperature signals of the target IGBT includes:

[0015] Obtain the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase temperature among the six-way junction temperature signals of the target IGBT;

[0016] Obtain the maximum value among the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase temperature as the highest junction temperature signal of the highest junction temperature curve of the target IGBT.

[0017] In an optional implementation manner, the obtaining the average junction temperature curve of the target IGBT includes:

[0018] Obtain the six-way junction temperature signals of the target IGBT;

[0019] Calculate the arithmetic mean of the six-way junction temperature signals of the target IGBT as the average junction temperature signal of the average junction temperature curve of the target IGBT.

[0020] In an optional implementation manner, the obtaining the highest junction temperature profile curve of the target IGBT according to the highest junction temperature curve and the average junction temperature curve of the target IGBT includes:

[0021] According to the highest junction temperature curve of the target IGBT, obtain the first highest junction temperature signal, the second highest junction temperature signal, and the third highest junction temperature signal; the first highest junction temperature signal is the highest junction temperature signal of the current calculation period, the second highest junction temperature signal is the highest junction temperature signal of the previous calculation period, and the third highest junction temperature signal is the highest junction temperature signal of the two previous calculation periods;

[0022] Judge whether the second highest junction temperature signal is greater than the third highest junction temperature signal, and judge whether the second highest junction temperature signal is greater than the first highest junction temperature signal;

[0023] If so, use the second highest junction temperature signal as the peak signal, and according to the average junction temperature curve of the target IGBT, obtain the average junction temperature signal at this time as the first average junction temperature signal;

[0024] Judge whether the peak signal is the peak point that appears for the first time;

[0025] If so, set the flag bit to 1, and when the flag bit is 1, according to the peak signal, the average junction temperature curve of the target IGBT, and the first average junction temperature signal, obtain the first preprocessing result of the highest junction temperature profile curve of the target IGBT;

[0026] When the flag bit is 0, use the first highest junction temperature signal as the second preprocessing result of the highest junction temperature profile curve of the target IGBT;

[0027] Judge whether the second preprocessing result is greater than the first preprocessing result;

[0028] If so, use the second preprocessing result as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT;

[0029] If not, use the first preprocessing result as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT.

[0030] Corresponding to the above IGBT junction temperature estimation method, the present application proposes an IGBT junction temperature estimation device, including:

[0031] The first acquisition unit is used to acquire the highest junction temperature curve of the target IGBT;

[0032] The second acquisition unit is used to acquire the average junction temperature curve of the target IGBT;

[0033] The third acquisition unit is used to acquire the highest junction temperature profile curve of the target IGBT according to the highest junction temperature curve and the average junction temperature curve of the target IGBT;

[0034] A junction temperature estimation unit for estimating the junction temperature of the target IGBT in real time according to the highest junction temperature profile curve of the target IGBT to obtain an estimation result.

[0035] In an optional implementation manner, the first acquisition unit includes:

[0036] A six-way signal acquisition sub-unit for acquiring six-way junction temperature signals of the target IGBT;

[0037] A first acquisition sub-unit for acquiring the highest junction temperature signal of the highest junction temperature curve of the target IGBT according to the six-way junction temperature signals of the target IGBT.

[0038] In an optional implementation manner, the first acquisition sub-unit includes:

[0039] A maximum value acquisition sub-unit for acquiring the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase value among the six-way junction temperature signals of the target IGBT;

[0040] A highest junction temperature acquisition sub-unit for acquiring the maximum value among the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase value as the highest junction temperature signal of the highest junction temperature curve of the target IGBT.

[0041] In an optional implementation manner, the second acquisition unit includes:

[0042] A six-way signal acquisition sub-unit for acquiring six-way junction temperature signals of the target IGBT;

[0043] An average junction temperature acquisition sub-unit for calculating the arithmetic mean of the six-way junction temperature signals of the target IGBT as the average junction temperature signal of the average junction temperature curve of the target IGBT.

[0044] In an optional implementation manner, the third acquisition unit includes:

[0045] A junction temperature signal acquisition sub-unit for acquiring a first highest junction temperature signal, a second highest junction temperature signal, and a third highest junction temperature signal according to the highest junction temperature curve of the target IGBT; the first highest junction temperature signal is the highest junction temperature signal of the current calculation period, the second highest junction temperature signal is the highest junction temperature signal of the previous calculation period, and the third highest junction temperature signal is the highest junction temperature signal of the two previous calculation periods;

[0046] A first judgment sub-unit for judging whether the second highest junction temperature signal is greater than the third highest junction temperature signal and judging whether the second highest junction temperature signal is greater than the first highest junction temperature signal;

[0047] A peak signal obtaining subunit, configured to, if it is determined that the second highest junction temperature signal is greater than the third highest junction temperature signal and the second highest junction temperature signal is greater than the first highest junction temperature signal, use the second highest junction temperature signal as the peak signal, and obtain the average junction temperature signal at this time according to the average junction temperature curve of the target IGBT as the first average junction temperature signal;

[0048] A second determination subunit, configured to determine whether the peak signal is the peak point that appears for the first time;

[0049] A first result obtaining subunit, configured to, if it is determined that the peak signal is the peak point that appears for the first time, set the flag bit to 1, and when the flag bit is 1, obtain the first preprocessing result of the highest junction temperature profile curve of the target IGBT according to the peak signal, the average junction temperature curve of the target IGBT, and the first average junction temperature signal;

[0050] A second result obtaining subunit, configured to, when the flag bit is 0, use the first highest junction temperature signal as the second preprocessing result of the highest junction temperature profile curve of the target IGBT;

[0051] A third determination subunit, configured to determine whether the second preprocessing result is greater than the first preprocessing result;

[0052] A first profile signal obtaining subunit, configured to, if it is determined that the second preprocessing result is greater than the first preprocessing result, use the second preprocessing result as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT;

[0053] A second profile signal obtaining subunit, configured to, if it is determined that the second preprocessing result is not greater than the first preprocessing result, use the first preprocessing result as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT.

[0054] Thus, the embodiments of the present application have the following beneficial effects:

[0055] The embodiments of the present application provide a method and device for estimating the IGBT junction temperature. After obtaining the maximum junction temperature curve and the average junction temperature curve of the target IGBT, the maximum junction temperature profile curve of the target IGBT can be obtained in real time according to the maximum junction temperature curve and the average junction temperature curve of the target IGBT. Thus, the junction temperature of the target IGBT can be estimated in real time according to the maximum junction temperature profile curve of the target IGBT, and an estimation result can be obtained. It can be seen that according to the characteristics that the maximum junction temperature curve fluctuates greatly but can reflect the maximum value, and the average junction temperature curve fluctuates gently but cannot reflect the maximum value, the embodiments of the present application extract the maximum junction temperature profile curve of the target IGBT in real time. This profile curve is more stable, can represent the maximum junction temperature of the target IGBT in real time, and when used to estimate the junction temperature of the target IGBT in real time, it can effectively reduce the fluctuation of the maximum junction temperature. When performing derating protection for excessive junction temperature, the fluctuation of the power output can be effectively reduced, ensuring the safe and reliable operation of the IGBT. Description of the Drawings

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0057] Figure 1 It is a flowchart of a method for estimating the IGBT junction temperature provided by the embodiments of the present application;

[0058] Figure 2 It is a schematic structural diagram of the maximum junction temperature signal for obtaining the maximum junction temperature curve of the target IGBT according to the six-channel junction temperature signals of the target IGBT provided by the embodiments of the present application;

[0059] Figure 3 It is a schematic diagram of the maximum junction temperature curve and the average junction temperature curve of the target IGBT provided by the embodiments of the present application;

[0060] Figure 4 It is a schematic structural diagram for obtaining the maximum junction temperature profile curve of the target IGBT according to the maximum junction temperature curve and the average junction temperature curve of the target IGBT provided by the embodiments of the present application;

[0061] Figure 5 It is a schematic flowchart for obtaining the maximum junction temperature profile curve of the target IGBT according to the maximum junction temperature curve and the average junction temperature curve of the target IGBT provided by the embodiments of the present application;

[0062] Figure 6 It is a comparative schematic diagram of the maximum junction temperature curve, the average junction temperature curve and the maximum junction temperature profile curve of the target IGBT provided by the embodiments of the present application;

[0063] Figure 7 This is the overall flowchart of a method for estimating the IGBT junction temperature according to an embodiment of the present application;

[0064] Figure 8 This is a schematic diagram of an apparatus for estimating the IGBT junction temperature provided by an embodiment of the present application. Detailed implementation manners

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0066] As is well known, the junction temperature of an IGBT is an important factor for evaluating the safety and lifespan of the IGBT. To ensure that the IGBT can operate safely and reliably in some high-power application scenarios for a long time, it is necessary to estimate the junction temperature of the IGBT online. Moreover, the IGBT itself has a limit on the maximum junction temperature. When the IGBT junction temperature exceeds this limit value, the IGBT will be at risk of reduced lifespan or even burnout. If the junction temperature can be estimated in real time, measures can be taken in advance for derating protection, thereby ensuring the safe and reliable operation of the IGBT.

[0067] However, the existing method for estimating the IGBT junction temperature using the IGBT maximum junction temperature curve may cause sudden changes or jitters in the system power during derating protection, thereby affecting the power output stability of the product. For example, in a vehicle, the adverse effects are unstable torque output and vehicle jitter.

[0068] Based on this, the present application proposes a method and an apparatus for estimating the IGBT junction temperature, which can extract the IGBT maximum junction temperature profile curve in real time to characterize the maximum junction temperature of the IGBT, and will not cause the estimated junction temperature to be too high or too low.

[0069] The following will describe in detail the method for estimating the IGBT junction temperature provided by the embodiments of the present application with reference to the accompanying drawings. Refer to Figure 1 As shown, it shows the flowchart of an embodiment of a method for estimating the IGBT junction temperature provided by an embodiment of the present application. This embodiment may include the following steps:

[0070] S101: Obtain the maximum junction temperature curve of the target IGBT.

[0071] In this embodiment, the IGBT for which the junction temperature needs to be estimated is defined as the target IGBT. In practical applications, in order to achieve real-time estimation of the junction temperature of the target IGBT, it is first necessary to obtain the maximum junction temperature curve of the target IGBT.

[0072] An optional implementation method is that the specific implementation process of obtaining the maximum junction temperature curve of the target IGBT in step S101 may include the following steps A1 - A2:

[0073] Step A1: Obtain six-way junction temperature signals of the target IGBT.

[0074] In this implementation method, since a target IGBT module usually includes three bridge arms, and each bridge arm includes two IGBTs, therefore, in order to obtain the maximum junction temperature curve of the target IGBT, it is first necessary to simultaneously obtain these six-way junction temperature signals of the target IGBT.

[0075] Step A2: According to the six-way junction temperature signals of the target IGBT, obtain the maximum junction temperature signal of the maximum junction temperature curve of the target IGBT.

[0076] After obtaining the six-way junction temperature signals of the target IGBT through step A1, further, according to these six-way junction temperature signals, the maximum junction temperature signal of the maximum junction temperature curve of the target IGBT can be obtained.

[0077] Specifically, an optional implementation method is that first, the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase value among the six-way junction temperature signals of the target IGBT can be obtained; then, the maximum value among the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase value can be obtained as the maximum junction temperature signal of the maximum junction temperature curve of the target IGBT.

[0078] In this implementation method, as Figure 2 shown, the six-way junction temperature signals of the target IGBT can be first divided into U-phase, V-phase, and W-phase. Among them, the two signals of the U-phase are the IGBTUH junction temperature and the IGBTUL junction temperature respectively; the two signals of the V-phase are the IGBTVH junction temperature and the IGBTVL junction temperature respectively; the two signals of the W-phase are the IGBTWH junction temperature and the IGBTWL junction temperature respectively. Then, the maximum value between the IGBTUH junction temperature and the IGBTUL junction temperature, the maximum value between the IGBTVH junction temperature and the IGBTVL junction temperature, and the maximum value between the IGBTWH junction temperature and the IGBTWL junction temperature are obtained respectively, and are used as the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase value respectively. Then, the maximum value among these three is calculated as the maximum junction temperature signal of the maximum junction temperature curve of the target IGBT, as Figure 3 shown, Figure 3 The uppermost contour wavy line in it is the maximum junction temperature curve of the target IGBT.

[0079] S102: Obtain the average junction temperature curve of the target IGBT.

[0080] In this embodiment, in order to achieve real-time estimation of the junction temperature of the target IGBT, it is also necessary to obtain the average junction temperature curve of the target IGBT.

[0081] An optional implementation manner is that the specific implementation process of obtaining the average junction temperature curve of the target IGBT in step S102 may include the following steps B1 - B2:

[0082] Step B1: Obtain six-way junction temperature signals of the target IGBT.

[0083] In this implementation manner, since a target IGBT module usually includes three bridge arms, and each bridge arm includes two IGBTs, in order to obtain the average junction temperature curve of the target IGBT, it is necessary to simultaneously obtain these six-way junction temperature signals of the target IGBT.

[0084] Step B2: Calculate the arithmetic mean of the six-way junction temperature signals of the target IGBT as the average junction temperature signal of the average junction temperature curve of the target IGBT.

[0085] After obtaining the six-way junction temperature signals of the target IGBT through step B1, further, the arithmetic mean of these six-way junction temperature signals can be calculated, and this arithmetic mean is used as the average junction temperature signal of the average junction temperature curve of the target IGBT, defined as X avg , as Figure 3 shown, Figure 3 The curve indicated by the middle arrow position is the average junction temperature curve of the target IGBT.

[0086] It should be noted that this embodiment does not limit the execution order of S101 and S102. S101 can be executed first and then S102, or S102 can be executed first and then S101, or S101 and S102 can be executed simultaneously.

[0087] S103: According to the highest junction temperature curve and the average junction temperature curve of the target IGBT, obtain the highest junction temperature profile curve of the target IGBT.

[0088] In this embodiment, after obtaining the highest junction temperature curve of the target IGBT through step S101 and the average junction temperature curve of the target IGBT through step S102, further, by performing data processing on the highest junction temperature curve and the average junction temperature curve of the target IGBT, the highest junction temperature profile curve of the target IGBT can be calculated. As Figure 4 shown, it shows a schematic structural diagram of obtaining the highest junction temperature profile curve of the target IGBT according to the highest junction temperature curve and the average junction temperature curve of the target IGBT.

[0089] Specifically, an optional implementation method is as follows. Refer to Figure 5 , the specific implementation process of this step S103 may include the following steps S1031 - S1032:

[0090] S1031: According to the highest junction temperature curve of the target IGBT, obtain the first highest junction temperature signal, the second highest junction temperature signal, and the third highest junction temperature signal.

[0091] In this implementation method, after obtaining the highest junction temperature curve of the target IGBT through step S101, the highest junction temperature signal, the second highest junction temperature signal, and the third highest junction temperature signal of the current calculation period can be further obtained.

[0092] Among them, the first highest junction temperature signal refers to the highest junction temperature signal of the current calculation period, defined as X3; the second highest junction temperature signal refers to the highest junction temperature signal of the previous calculation period, defined as X2; the third highest junction temperature signal refers to the highest junction temperature signal of the two previous calculation periods, defined as X1. The value of the calculation period varies according to different product requirements and can usually be taken as a value between 1 ms and 10 ms.

[0093] S1032: Judge whether the second highest junction temperature signal is greater than the third highest junction temperature signal, and judge whether the second highest junction temperature signal is greater than the first highest junction temperature signal.

[0094] After obtaining the first highest junction temperature signal, the second highest junction temperature signal, and the third highest junction temperature signal through step S1031, it can be further judged whether the second highest junction temperature signal is greater than the third highest junction temperature signal, and judge whether the second highest junction temperature signal is greater than the first highest junction temperature signal, that is, judge whether X2 > X1 and X2 > X3 hold simultaneously.

[0095] S1033: If so, use the second highest junction temperature signal as the peak signal, and according to the average junction temperature curve of the target IGBT, obtain the average junction temperature signal at this time as the first average junction temperature signal.

[0096] If it is judged through step S1032 that the second highest junction temperature signal is greater than the third highest junction temperature signal and the second highest junction temperature signal is greater than the first highest junction temperature signal, that is, X2 > X1 and X2 > X3 hold simultaneously, then the second highest junction temperature signal X2 can be used as the peak signal, defined as X max , which also indicates that a peak point appears, that is, the highest junction temperature signal of the previous calculation period represented by the second highest junction temperature signal X2 is the peak point.

[0097] And at the same time, according to the average junction temperature curve of the target IGBT, the average junction temperature signal at this time can be obtained as the first average junction temperature signal, defined as X avg0 .

[0098] After that, every time X2 > X1 and X2 > X3 are satisfied, the peak point X is updated. max , and the average junction temperature X corresponding to this moment avg0 .

[0099] S1034: Determine whether the peak signal is the peak point that appears for the first time.

[0100] After determining through step S1033 that the highest junction temperature signal of the previous calculation period characterized by the second highest junction temperature signal X2 is the peak point, it can be further determined whether the peak signal is the peak point that appears for the first time.

[0101] S1035: If so, set the flag bit to 1, and when the flag bit is 1, obtain the first preprocessing result of the highest junction temperature profile curve of the target IGBT according to the peak signal, the average junction temperature curve of the target IGBT, and the first average junction temperature signal.

[0102] If it is determined through step S1034 that the peak signal is the peak point that appears for the first time, set the flag bit (Flag) to 1 and keep it, and then according to the peak signal, the average junction temperature curve of the target IGBT, and the first average junction temperature signal X avg0 , obtain the first preprocessing result of the highest junction temperature profile curve of the target IGBT, defined as X outbef1 , and the specific calculation formula is as follows:

[0103] X outbef1 = X max + X avg - X avg0 (1)

[0104] Among them, X outbef1 represents the first preprocessing result of the highest junction temperature profile curve of the target IGBT; X max represents the peak signal; X avg represents the average junction temperature of the target IGBT; X avg0 represents that when the peak point appears for the first time (that is, X2 > X1 and X2 > X3, record the peak point signal X max as X2), and when Flag is set to 1 and kept, the average junction temperature of the target IGBT corresponding to this moment.

[0105] S1036: When the flag bit is 0, use the first highest junction temperature signal as the second preprocessing result of the highest junction temperature profile curve of the target IGBT.

[0106] Specifically, when the flag bit is 0, that is, when Flag = 0, the first highest junction temperature signal X3 can be used as the second preprocessing result of the highest junction temperature profile curve of the target IGBT, defined as Xoutbef2 That is, X outbef2 = X3.

[0107] S1037: Determine whether the second preprocessing result is greater than the first preprocessing result.

[0108] Through step S1035, the first preprocessing result X of the highest junction temperature profile curve of the target IGBT is obtained outbef1 , and through step S1036, the second preprocessing result X of the highest junction temperature profile curve of the target IGBT is obtained outbef2 After that, it can be further determined whether the second preprocessing result X outbef2 is greater than the first preprocessing result X outbef1 . If so, execute step S1038; if not, execute step S1039.

[0109] S1038: If so, use the second preprocessing result as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT.

[0110] If it is determined through step S1037 that the second preprocessing result X outbef2 is greater than the first preprocessing result X outbef1 , then the second preprocessing result X outbef2 can be used as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT. That is, X3 is the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT.

[0111] S1039: If not, use the first preprocessing result as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT.

[0112] If it is determined through step S1037 that the second preprocessing result X outbef2 is not greater than the first preprocessing result X outbef1 , then the first preprocessing result X outbef1 can be used as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT. That is, X max + X avg - X avg0 is the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT.

[0113] S104: According to the highest junction temperature profile curve of the target IGBT, perform real-time estimation on the junction temperature of the target IGBT to obtain an estimation result.

[0114] In this embodiment, after obtaining the highest junction temperature profile curve of the target IGBT through step S103, the highest junction temperature of the target IGBT can be characterized in real time using this highest junction temperature profile line. Also, based on this highest junction temperature profile curve, the junction temperature of the target IGBT can be estimated in real time to obtain an estimation result. As a result, the fluctuation of the highest junction temperature can be effectively reduced for derating protection. That is, when the junction temperature is too high, the output power can be reduced according to the value of the junction temperature to lower the junction temperature, and finally dynamically adjusted to a stable value, thereby ensuring the safe and reliable operation of the target IGBT.

[0115] It can be understood that the highest junction temperature curve, average junction temperature curve, and highest junction temperature profile curve of the target IGBT can also be plotted on one graph for comparative analysis to more intuitively see the beneficial effects of the highest junction temperature profile curve.

[0116] For example: Refer to Figure 6 , when a certain motor control system operates at 10 RPM and 100 Nm, through the above method, the obtained highest junction temperature curve, average junction temperature curve, and highest junction temperature profile curve are as Figure 6 shown. From Figure 6 it can be seen that the fluctuation amplitude of the highest junction temperature curve is relatively large, and the maximum fluctuation after stabilization can reach about 15°C. The average junction temperature curve cannot well characterize the highest junction temperature, is significantly lower, and is about 30°C lower. While the highest junction temperature profile curve has a gentle fluctuation, the fluctuation after stabilization is about 3°C, and it can better characterize the highest junction temperature.

[0117] Therefore, for an IGBT junction temperature estimation method provided by an embodiment of the present application, after obtaining the highest junction temperature curve and average junction temperature curve of the target IGBT, based on the highest junction temperature curve and average junction temperature curve of the target IGBT, the highest junction temperature profile curve of the target IGBT is obtained in real time. Thus, based on this highest junction temperature profile curve of the target IGBT, the junction temperature of the target IGBT can be estimated in real time to obtain an estimation result. It can be seen that according to the characteristics that the highest junction temperature curve has a large fluctuation but can reflect the highest value, and the average junction temperature curve has a gentle fluctuation but cannot reflect the highest value, the highest junction temperature profile curve of the target IGBT is extracted in real time. This profile curve is more stable, can characterize the highest junction temperature of the target IGBT in real time, and when used to estimate the junction temperature of the target IGBT in real time, it can effectively reduce the fluctuation of the highest junction temperature. When performing derating protection for too high junction temperature, it can effectively reduce the fluctuation of power output and ensure the safe and reliable operation of the IGBT.

[0118] For ease of understanding, now in combination with Figure 7 the overall flowchart of an IGBT junction temperature estimation method shown. The implementation process of the IGBT junction temperature estimation method provided by an embodiment of the present application will be introduced.

[0119] S701: First, synchronously compare the six IGBT junction temperature signals, extract the highest junction temperature. For the specific implementation process, refer to step S101. Then, execute step S702.

[0120] S702: Obtain the highest junction temperature signals X3, X2, and X1 of the current calculation period, the previous calculation period, and the two previous calculation periods.

[0121] S703: Determine whether X2 > X1 and X2 > X3 hold.

[0122] S704: If X2 > X1 and X2 > X3 hold, record the peak point signal X max = X2.

[0123] S705: Determine whether the peak point appears for the first time.

[0124] S706: If it is determined that the peak point appears for the first time, the first appearance flag bit Flag = 1 and remains 1.

[0125] S707: Determine whether the flag bit Flag is 1. If the flag bit Flag is 1, the preprocessed result of the profile curve is X outbef1 , and the specific calculation formula is: X outbef1 = X max + X avg - X avg0 ; if the flag bit Flag is 0, the preprocessed result of the profile curve is X outbef2 , and the specific calculation formula is X outbef2 = X3.

[0126] S708: Determine whether X outbef2 > X outbef1 holds. If it holds, the output result of the highest junction temperature profile curve is X outbef2 ; if it does not hold, the output result of the highest junction temperature profile curve is X outbef1 . For the specific implementation process of steps S702 - S708, refer to steps S1031 - S1039.

[0127] Refer to Figure 8 As shown, this application also provides an embodiment of an IGBT junction temperature estimation device, which may include:

[0128] The first acquisition unit 801 is used to acquire the highest junction temperature curve of the target IGBT;

[0129] The second acquisition unit 802 is used to acquire the average junction temperature curve of the target IGBT;

[0130] A third acquisition unit 803, configured to obtain a highest junction temperature profile curve of the target IGBT according to the highest junction temperature curve and the average junction temperature curve of the target IGBT;

[0131] A junction temperature estimation unit 804, configured to perform real-time estimation on the junction temperature of the target IGBT according to the highest junction temperature profile curve of the target IGBT, and obtain an estimation result.

[0132] In some possible implementation manners of this application, the first acquisition unit 801 includes:

[0133] A six-channel signal acquisition subunit, configured to acquire six-channel junction temperature signals of the target IGBT;

[0134] A first acquisition subunit, configured to acquire a highest junction temperature signal of the highest junction temperature curve of the target IGBT according to the six-channel junction temperature signals of the target IGBT.

[0135] In some possible implementation manners of this application, the first acquisition subunit includes:

[0136] A maximum value acquisition subunit, configured to acquire a maximum U-phase junction temperature, a maximum V-phase junction temperature, and a maximum W-phase value in the six-channel junction temperature signals of the target IGBT;

[0137] A highest junction temperature acquisition subunit, configured to acquire the maximum value among the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase value as the highest junction temperature signal of the highest junction temperature curve of the target IGBT.

[0138] In some possible implementation manners of this application, the second acquisition unit 802 includes:

[0139] A six-channel signal acquisition subunit, configured to acquire six-channel junction temperature signals of the target IGBT;

[0140] An average junction temperature acquisition subunit, configured to calculate an arithmetic mean of the six-channel junction temperature signals of the target IGBT as the average junction temperature signal of the average junction temperature curve of the target IGBT.

[0141] In some possible implementation manners of this application, the third acquisition unit 803 includes:

[0142] A junction temperature signal acquisition subunit, configured to acquire a first highest junction temperature signal, a second highest junction temperature signal, and a third highest junction temperature signal according to the highest junction temperature curve of the target IGBT; the first highest junction temperature signal is the highest junction temperature signal of the current calculation period, the second highest junction temperature signal is the highest junction temperature signal of the previous calculation period, and the third highest junction temperature signal is the highest junction temperature signal of the two previous calculation periods;

[0143] The first judgment subunit is configured to judge whether the second highest junction temperature signal is greater than the third highest junction temperature signal, and judge whether the second highest junction temperature signal is greater than the first highest junction temperature signal;

[0144] The peak signal acquisition subunit is configured to, if it is judged that the second highest junction temperature signal is greater than the third highest junction temperature signal, and it is judged that the second highest junction temperature signal is greater than the first highest junction temperature signal, then use the second highest junction temperature signal as the peak signal, and obtain the average junction temperature signal at this time according to the average junction temperature curve of the target IGBT as the first average junction temperature signal;

[0145] The second judgment subunit is configured to judge whether the peak signal is the peak point that appears for the first time;

[0146] The first result acquisition subunit is configured to, if it is judged that the peak signal is the peak point that appears for the first time, set the flag bit to 1, and when the flag bit is 1, obtain the first preprocessing result of the highest junction temperature profile curve of the target IGBT according to the peak signal, the average junction temperature curve of the target IGBT, and the first average junction temperature signal;

[0147] The second result acquisition subunit is configured to, when the flag bit is 0, use the first highest junction temperature signal as the second preprocessing result of the highest junction temperature profile curve of the target IGBT;

[0148] The third judgment subunit is configured to judge whether the second preprocessing result is greater than the first preprocessing result;

[0149] The first profile signal acquisition subunit is configured to, if it is judged that the second preprocessing result is greater than the first preprocessing result, use the second preprocessing result as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT;

[0150] The second profile signal acquisition subunit is configured to, if it is judged that the second preprocessing result is not greater than the first preprocessing result, use the first preprocessing result as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT.

[0151] As can be seen from the above embodiments, the IGBT junction temperature estimation device provided by the embodiments of the present application, after obtaining the maximum junction temperature curve and the average junction temperature curve of the target IGBT, according to the maximum junction temperature curve and the average junction temperature curve of the target IGBT, the maximum junction temperature profile curve of the target IGBT is obtained in real time. Thus, according to the maximum junction temperature profile curve of the target IGBT, the junction temperature of the target IGBT can be estimated in real time to obtain an estimation result. It can be seen that according to the characteristics that the maximum junction temperature curve fluctuates greatly but can reflect the maximum value, and the average junction temperature curve fluctuates gently but cannot reflect the maximum value, the embodiments of the present application extract the maximum junction temperature profile curve of the target IGBT in real time. This profile curve is smoother, can represent the maximum junction temperature of the target IGBT in real time, and when used to estimate the junction temperature of the target IGBT in real time, can effectively reduce the fluctuation of the maximum junction temperature. When performing derating protection for over-high junction temperature, it can effectively reduce the fluctuation of power output and ensure the safe and reliable operation of the IGBT.

[0152] From the description of the above embodiments, those skilled in the art can clearly understand that all or part of the steps in the above embodiment methods can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disc, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present application.

[0153] It should be noted that the various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0154] It should also be noted that, in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0155] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for estimating the IGBT junction temperature, characterized in that, Including: Obtain the highest junction temperature curve of the target IGBT; Obtain the average junction temperature curve of the target IGBT; According to the highest junction temperature curve and the average junction temperature curve of the target IGBT, obtain the highest junction temperature profile curve of the target IGBT; According to the highest junction temperature profile curve of the target IGBT, perform real-time estimation on the junction temperature of the target IGBT to obtain an estimation result; The obtaining the highest junction temperature profile curve of the target IGBT according to the highest junction temperature curve and the average junction temperature curve of the target IGBT includes: According to the highest junction temperature curve of the target IGBT, obtain a first highest junction temperature signal, a second highest junction temperature signal, and a third highest junction temperature signal; the first highest junction temperature signal is the highest junction temperature signal of the current calculation period, the second highest junction temperature signal is the highest junction temperature signal of the previous calculation period, and the third highest junction temperature signal is the highest junction temperature signal of the two previous calculation periods; Judge whether the second highest junction temperature signal is greater than the third highest junction temperature signal, and judge whether the second highest junction temperature signal is greater than the first highest junction temperature signal; If so, use the second highest junction temperature signal as the peak signal, and according to the average junction temperature curve of the target IGBT, obtain the average junction temperature signal at this time as the first average junction temperature signal; Judge whether the peak signal is the peak point that appears for the first time; If so, set the flag bit to 1, and when the flag bit is 1, obtain the first preprocessing result of the highest junction temperature profile curve of the target IGBT according to the peak signal, the average junction temperature curve of the target IGBT, and the first average junction temperature signal; define the first preprocessing result as X outbef1 , and the specific calculation formula is as follows: X outbef1 = X max + X avg - X avg0 Among them, X outbef1 represents the first preprocessing result of the highest junction temperature profile curve of the target IGBT; X max represents the peak signal; X avg represents the average junction temperature of the target IGBT; X avg0 represents the average junction temperature of the target IGBT corresponding to the moment when the peak point first appears, the flag bit is set to 1 and remains unchanged. When the flag bit is 0, use the first highest junction temperature signal as the second preprocessing result of the highest junction temperature profile curve of the target IGBT; Judge whether the second preprocessing result is greater than the first preprocessing result; If so, use the second preprocessing result as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT; If not, use the first preprocessing result as the corresponding highest junction temperature profile signal of the highest junction temperature profile curve of the target IGBT.

2. The method according to claim 1, wherein The obtaining the highest junction temperature curve of the target IGBT includes: Obtain six-way junction temperature signals of the target IGBT; According to the six-way junction temperature signals of the target IGBT, obtain the highest junction temperature signal of the highest junction temperature curve of the target IGBT.

3. The method according to claim 2, characterized in that The obtaining the highest junction temperature signal of the highest junction temperature curve of the target IGBT according to the six-way junction temperature signals of the target IGBT includes: Obtain the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase value among the six-way junction temperature signals of the target IGBT; Obtain the maximum value among the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase value as the highest junction temperature signal of the highest junction temperature curve of the target IGBT.

4. The method according to claim 1, characterized in that, The obtaining the average junction temperature curve of the target IGBT includes: Obtain six-way junction temperature signals of the target IGBT; Calculate the arithmetic mean of the six-way junction temperature signals of the target IGBT as the average junction temperature signal of the average junction temperature curve of the target IGBT.

5. An IGBT junction temperature estimation device, characterized in that, Including: A first obtaining unit for obtaining the highest junction temperature curve of the target IGBT; A second obtaining unit for obtaining the average junction temperature curve of the target IGBT; A third acquisition unit, configured to obtain a maximum junction temperature profile curve of the target IGBT according to the maximum junction temperature curve and the average junction temperature curve of the target IGBT; A junction temperature estimation unit, configured to perform real-time estimation on the junction temperature of the target IGBT according to the maximum junction temperature profile curve of the target IGBT to obtain an estimation result; The third acquisition unit includes: A junction temperature signal acquisition subunit, configured to obtain a first maximum junction temperature signal, a second maximum junction temperature signal, and a third maximum junction temperature signal according to the maximum junction temperature curve of the target IGBT; the first maximum junction temperature signal is the maximum junction temperature signal of the current calculation period, the second maximum junction temperature signal is the maximum junction temperature signal of the previous calculation period, and the third maximum junction temperature signal is the maximum junction temperature signal of the two previous calculation periods; A first judgment subunit, configured to judge whether the second maximum junction temperature signal is greater than the third maximum junction temperature signal, and judge whether the second maximum junction temperature signal is greater than the first maximum junction temperature signal; A peak signal acquisition subunit, configured to, if it is judged that the second maximum junction temperature signal is greater than the third maximum junction temperature signal and the second maximum junction temperature signal is greater than the first maximum junction temperature signal, use the second maximum junction temperature signal as the peak signal, and obtain the average junction temperature signal at this time according to the average junction temperature curve of the target IGBT as the first average junction temperature signal; A second judgment subunit, configured to judge whether the peak signal is the peak point that appears for the first time; A first result acquisition subunit is configured to set the flag bit to 1 if it is determined that the peak signal is the peak point that appears for the first time, and when the flag bit is 1, obtain a first preprocessing result of the highest junction temperature profile curve of the target IGBT according to the peak signal, the average junction temperature curve of the target IGBT, and the first average junction temperature signal; define the first preprocessing result as X outbef1 , and the specific calculation formula is as follows: X outbef1 = X max + X avg - X avg0 Among them, X outbef1 represents the first preprocessing result of the highest junction temperature profile curve of the target IGBT; X max represents the peak signal; X avg represents the average junction temperature of the target IGBT; X avg0 represents the average junction temperature of the target IGBT corresponding to the moment when the peak point first appears, the flag bit is set to 1 and remains unchanged. A second result acquisition subunit, configured to, when the flag bit is 0, use the first maximum junction temperature signal as the second preprocessing result of the maximum junction temperature profile curve of the target IGBT; A third judgment subunit, configured to judge whether the second preprocessing result is greater than the first preprocessing result; A first profile signal acquisition subunit, configured to, if it is judged that the second preprocessing result is greater than the first preprocessing result, use the second preprocessing result as the corresponding maximum junction temperature profile signal of the maximum junction temperature profile curve of the target IGBT; A second profile signal acquisition subunit, configured to, if it is judged that the second preprocessing result is not greater than the first preprocessing result, use the first preprocessing result as the corresponding maximum junction temperature profile signal of the maximum junction temperature profile curve of the target IGBT.

6. The device according to claim 5, wherein The first acquisition unit includes: A six-way signal acquisition subunit, configured to acquire six-way junction temperature signals of the target IGBT; A first acquisition subunit, configured to obtain the maximum junction temperature signal of the maximum junction temperature curve of the target IGBT according to the six-way junction temperature signals of the target IGBT.

7. The device according to claim 6, characterized in that, The first acquisition subunit includes: A maximum value acquisition subunit, configured to obtain the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase value among the six-way junction temperature signals of the target IGBT; A maximum junction temperature acquisition subunit, configured to obtain the maximum value among the maximum U-phase junction temperature, the maximum V-phase junction temperature, and the maximum W-phase value as the maximum junction temperature signal of the maximum junction temperature curve of the target IGBT.

8. The device according to claim 7, characterized in that, The second acquisition unit includes: Six-channel signal acquisition sub-unit, configured to acquire six-channel junction temperature signals of the target IGBT; Average junction temperature acquisition sub-unit, configured to calculate the arithmetic mean of the six-channel junction temperature signals of the target IGBT as the average junction temperature signal of the average junction temperature curve of the target IGBT.

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