1. An IGBT module packaging aging online health management method is characterized by comprising the following steps:

the method comprises the following steps: determining an aged IGBT module according to the rise rate of the collector current when each IGBT module in the parallel IGBT modules is switched on;

step two: recording the current rise rate of each parallel IGBT module in the switching-on process when the system starts to operate, and carrying out ratio on the current rise rate of each module to be used as a reference value;

step three: and extracting the current rise rate of each parallel IGBT module in the switching-on process in the operation process of the system, carrying out a ratio, comparing the ratio with a reference value, and positioning the aging module.

2. The IGBT module package aging on-line health management method according to claim 1, characterized in thatDetermining a current rise distortion rate for each aging module, wherein di_cAnd di_cThe current rise rate of two IGBT modules is measured, beta is the ratio of the current rise rate recorded when the system starts to operate, beta' is the ratio of the current rise rate measured when the system is subjected to aging detection, and gamma is the current rise distortion rate; before obtaining the current rise distortion rate, the method further comprises: current collection for periodically testing each module when it is switched onThe rate of rise of the pole current.

3. The IGBT module package aging on-line health management method according to claim 2, wherein judging whether the aging module meets the aging standard comprises: and judging whether the current rising distortion rate gamma reaches a threshold value, if so, judging that the device is aged, and replacing the device or derating according to the actual condition.

4. The IGBT module package aging on-line health management method according to claim 3, wherein judging the aging type of the aging module comprises the following criteria:

comparing the shell temperature of the aging module with that of the normal module, and judging that the bonding wire is aged if the shell temperature of the aging module is lower than that of the normal module; and if the shell temperature of the aging module is equal to that of the normal module, judging that the solder layer is aged.

5. The IGBT module package aging on-line health management method according to claim 4, wherein the health management model of bonding wire aging is as follows:

if it isThen

The health management model of the aging of the solder layer is as follows:

if it isThen

Wherein the content of the first and second substances,andthe module transconductance of the two modules being measured,andfor the gate emitter voltages of the two modules to be measured,andto measure the bond wire resistance of both modules,andthe chip transconductance, T, of the two modules measured respectively_jIs the temperature of the chip inside the IGBT module, T_typThe classical chip temperature set for the IGBT module manual is 25 ℃, and T is_maxIs an IGBT moduleThe maximum value of the temperature of the block chip is 175 ℃ in g_{m_max}And g_{m_typ}For IGBT modules respectively at T_maxAnd T_typThe module transconductance at two temperatures, k and b are constants after simplification,andtemperature, P, of two modules respectively_lossIs the loss of the chip inside the module, r_jcIs the junction-to-case thermal resistance, T, of the IGBT module_cThe case temperature of the IGBT module is delta r, and the delta r is the increment of thermal resistance caused when the chip is subjected to solder layer aging.

6. The IGBT module package aging on-line health management method according to claim 5, wherein the aging failure criterion is judged according to the aging type, and the method comprises the following steps:

and if the aging type of the IGBT module is bonding wire aging, solving the resistance variation of the bonding wire of the IGBT module according to the current rise distortion rate and a health management model of the bonding wire aging, and if the resistance variation exceeds 10%, judging that the bonding wire is aged and invalid.

And if the aging type of the IGBT module is bonding wire aging, calculating the thermal resistance variation of the solder layer of the IGBT module according to the current rise distortion rate and a health management model of the aging of the solder layer, and if the thermal resistance variation exceeds 20%, judging that the solder layer is aged and failed.

7. An IGBT module package aging online health management system is characterized by comprising the IGBT module package aging online health management method according to claims 1-6.

Background

insulated-Gate Bipolar Transistor (IGBT) is one of the most widely used power electronic devices in the field of power systems, and its current-carrying capacity determines the capacity of the power system. At present, aiming at the problem that a single IGBT chip cannot bear excessive voltage and current, a common solution is to integrate multiple chips into one module, and connect multiple modules in parallel to form a system to improve the power level of the system. Meanwhile, in some multi-level converters, there are cases where multiple power electronic devices are turned on simultaneously. This makes it important to perform state detection and health management in parallel mode as effective as possible. In an ideal case, the current distribution of the parallel-connected IGBTs during the switching on and off will be exactly the same. In practical applications, the current distribution is not well balanced due to the slight differences between the manufacturing process and the usage environment. Even in this case, however, the system can still function properly. But after the device is aged, the unbalanced effect of the current is amplified, thereby affecting the operation of the whole system. Therefore, the key of ensuring the stable operation of the system is realized when the modules in the system are regularly managed.

In the field of power systems, sudden failures often lead to serious consequences, resulting in great economic losses. How to timely monitor the potential failure factor before the failure occurs becomes a key issue. Among these, gradual failures caused by package aging tend to be more difficult to predict, as failure is a process that becomes quantitative to qualitative. Early aging of the package is usually accompanied by voids in the solder layer and fracture of the bond wires, which has no effect on the proper functioning of the entire module. However, when the voids in the solder layer gradually increase and the number of broken bonds and wires gradually increases, the junction temperature increases, the electrothermal stress is too large, and the chip falls off, thereby causing short circuit and open circuit of the system. No matter in which mode, in the aging process, the voltage and current changes of the parallel modules are greatly different from those of the single tubes, and the aging process is the vacuum of the current health management.

Disclosure of Invention

In view of the above defects or improvement requirements of the prior art, the invention provides an IGBT module package aging online health management method and system capable of monitoring potential failure factors online in a high-frequency operating state.

The technical scheme adopted for solving the technical problem is that the online health management method for the packaging aging of the IGBT module comprises the following steps:

the method comprises the following steps: determining an aged IGBT module according to the rise rate of the collector current when each IGBT module in the parallel IGBT modules is switched on;

step two: recording the current rise rate of each parallel IGBT module in the switching-on process when the system starts to operate, and carrying out ratio on the current rise rate of each module to be used as a reference value;

step three: and extracting the current rise rate of each parallel IGBT module in the switching-on process in the operation process of the system, carrying out a ratio, comparing the ratio with a reference value, and positioning the aging module.

Further, by Determining a current rise distortion rate for each aging module, wherein di_cAnd di_cThe current rise rate of two IGBT modules is measured, beta is the ratio of the current rise rate recorded when the system starts to operate, beta' is the ratio of the current rise rate measured when the system is subjected to aging detection, and gamma is the current rise distortion rate; before obtaining the current rise distortion rate, the method further comprises: and periodically testing the rise rate of the collector current when each module is switched on.

Further, the judging whether the aging module reaches the aging standard includes: and judging whether the current rising distortion rate gamma reaches a threshold value, if so, judging that the device is aged, and replacing the device or derating according to the actual condition.

Further, judging the aging type of the aging module, wherein the aging type comprises the following standards:

comparing the shell temperature of the aging module with that of the normal module, and judging that the bonding wire is aged if the shell temperature of the aging module is lower than that of the normal module; and if the shell temperature of the aging module is equal to that of the normal module, judging that the solder layer is aged.

Further, the health management model of the aging of the bonding wire is as follows:

if it isThen

The health management model of the aging of the solder layer is as follows:

if it isThen

Wherein the content of the first and second substances,andare respectively aThe module transconductance of both modules is measured,andfor the gate emitter voltages of the two modules to be measured,andto measure the bond wire resistance of both modules,andthe chip transconductance, T, of the two modules measured respectively_jIs the temperature of the chip inside the IGBT module, T_typThe classical chip temperature set for the IGBT module manual is 25 ℃, and T is_maxThe maximum value of the temperature of the IGBT module chip is 175 ℃, g_{m_max}And g_{m_typ}For IGBT modules respectively at T_maxAnd T_typThe module transconductance at two temperatures, k and b are constants after simplification,andtemperature, P, of two modules respectively_lossIs the loss of the chip inside the module, r_jcIs the junction-to-case thermal resistance, T, of the IGBT module_cThe case temperature of the IGBT module is delta r, and the delta r is the increment of thermal resistance caused when the chip is subjected to solder layer aging.

Further, judging an aging failure standard according to the aging type, comprising:

and if the aging type of the IGBT module is bonding wire aging, solving the resistance variation of the bonding wire of the IGBT module according to the current rise distortion rate and a health management model of the bonding wire aging, and if the resistance variation exceeds 10%, judging that the bonding wire is aged and invalid.

And if the aging type of the IGBT module is bonding wire aging, calculating the thermal resistance variation of the solder layer of the IGBT module according to the current rise distortion rate and a health management model of the aging of the solder layer, and if the thermal resistance variation exceeds 20%, judging that the solder layer is aged and failed.

An IGBT module packaging aging online health management system comprises an IGBT module packaging aging online health management method.

According to the invention, detailed research is carried out on the electrical characteristics of the switching transient state of the IGBT module according to the current application development situation of the IGBT module, on the basis of the switching transient state, the influence of parallel connection of the modules on the switching current is researched, a health management method based on the transient switching current is established, and the potential aging failure in the package can be found on line through real-time current detection, so that the systematic fault caused by the aging of devices is avoided.

Drawings

FIG. 1 is a flow chart of an embodiment of the present invention;

FIG. 2 is an equivalent circuit diagram of the parallel module turn-on process in the embodiment of the present invention;

fig. 3 is a diagram showing simulation results of collector current distribution of a fault module and a normal module in the embodiment of the present invention, in which, (a) is a current distribution simulation diagram of each module when 6 bonding wires fall off, (b) is a current distribution simulation diagram of each module when 4 bonding wires fall off, (c) is a current distribution simulation diagram of each module when 2 bonding wires fall off, and (d) is a current distribution simulation diagram of each module when 1 bonding wire falls off;

fig. 4 is a diagram showing experimental results of collector current distribution of a failed module and a normal module in an embodiment of the present invention, where (a) is a diagram showing experimental results of current distribution of two modules when four bonding wires fall off, (b) is a diagram showing experimental results of current distribution of two modules when two bonding wires fall off, and (c) is a diagram showing experimental results of current distribution of two modules when the two bonding wires are normal.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1, the present embodiment includes the steps of:

s1: extracting and recording the collector current rise rate of each IGBT module when the parallel IGBT module system starts to operate and carrying out ratio as a reference value;

s2: extracting the current rise rate of each IGBT module collector, carrying out a specific value, and comparing the specific value with a reference value to obtain a current rise distortion rate;

in an embodiment, the current rise rate of each module measured periodically is compared with a current rise rate reference value, and the current rise rate of the aged module is smaller than that of the normal module. Their ratio is defined as the current rise distortion rate.

S3: extracting the shell temperature of the aging module, and judging the aging mode;

the shell temperature of each IGBT module in the parallel IGBT modules can be compared, the IGBT module with the shell temperature lower than the shell temperature values of other normal modules is used as a bonding wire aging IGBT module, and the IGBT module with the shell temperature equal to the shell temperature values of other normal modules is used as a solder layer aging IGBT module.

S4: and substituting the current rising distortion rate into a parallel IGBT module packaging aging online health management model to perform aging positioning.

In the embodiment of the present invention, the method for calculating the current rise distortion rate in step S2 includes:

wherein di_cAnd di_cThe current rise rate of two IGBT modules is measured, beta is the ratio of the current rise rates recorded when the system starts to operate, beta' is the ratio of the current rise rates measured when the system is subjected to aging detection, and gamma is the current rise distortion rate.

In an embodiment of the present invention, the parallel IGBT module package aging online health management model in step S4 includes a bonding wire aging health management model and a solder layer aging health management model, where:

the bonding wire aging health management model comprises:

if it isThen

The aging health management model of the solder layer is as follows:

if it isThen

Wherein the content of the first and second substances,andthe module transconductance of the two modules being measured,andfor the gate emitter voltages of the two modules to be measured,andto measure the bond wire resistance of both modules,andthe chip transconductance of the two modules measured, respectively. T is_jIs the temperature of the chip inside the IGBT module, T_typThe classical chip temperature set for the IGBT module manual is typically 25 ℃, T_maxThe maximum value of the temperature of the IGBT module chip is usually 175 ℃, g_{m_max}And g_{m_typ}For IGBT modules respectively at T_maxAnd T_typThe module transconductance, k and b, at two temperatures are constants after simplification.Andtemperature, P, of two modules respectively_lossIs the loss of the chip inside the module, r_jcIs the junction-to-case thermal resistance, T, of the IGBT module_cThe case temperature of the IGBT module is delta r, and the delta r is the increment of thermal resistance caused when the chip is subjected to solder layer aging.

The equivalent circuit of each branch in parallel is shown in fig. 2, the electrical characteristics of each IGBT module can be represented by a resistor and a voltage source respectively simulating an on-resistance and a turn-on voltage drop, and the bonding wire can be represented by a plurality of resistors in parallel. The parasitic capacitance effect of the turn-on process can be represented by a junction capacitance in parallel with the gate and the emitter. When one of the bonding wires falls off, the driving voltage cannot be changed because all the parallel modules share one driving circuit, but the voltage distributed to the chip is correspondingly reduced under the condition that the resistance of the bonding wire is increased, which is the basic principle of the invention.

Fig. 3 is a diagram showing the current distribution simulation results of collectors of a fault module and a normal module, wherein (a) is a current distribution simulation diagram of each module when 6 bonding wires fall off, (b) is a current distribution simulation diagram of each module when 4 bonding wires fall off, (c) is a current distribution simulation diagram of each module when 2 bonding wires fall off, and (d) is a current distribution simulation diagram of each module when 1 bonding wire falls off.

Fig. 4 is a diagram of experimental verification of collector current distribution between a failed module and a normal module, wherein the lower box represents the normal module and the upper box represents the aging module.

As can be seen from fig. 3 and 4, the IGBT collector rate of rise varies differently under the condition of different numbers of bonding wires being disconnected, which is specifically indicated that the more the number of bonding wires falls off, the larger the ratio of the collector current rate of rise.

The embodiment also includes an IGBT module package aging online health management system, which applies the above-described IGBT module package aging online health management method, and specifically includes the following modules:

a current rise distortion rate calculation module: the current rise rate extraction module is used for extracting the rise rate of the collector current of each IGBT module in the parallel IGBT modules in the switching-on process, comparing the rise rate with an initial reference value and calculating to obtain a current rise distortion rate;

an aging judgment module: the module is used for judging and positioning the aging of the parallel IGBT module;

a health management module: and substituting the measured current rising distortion rate and the shell temperature into an aging online health management model of the parallel IGBT module package, judging the current health state of the IGBT module package, and replacing devices or derating the aging module according to the actual condition.

Various modifications and variations of the present invention may be made by those skilled in the art, and they are still within the scope of the present patent invention provided they are within the scope of the claims and their equivalents.

What is not described in detail in the specification is prior art that is well known to those skilled in the art.