A method for evaluating the micro-motion wear aging state of a crimping type IGBT device

Abstract

The application discloses a kind of crimping type IGBT device micro-motion wear aging state evaluation method, it is related to IGBT device state monitoring technical field.For the lack of uniform, targeted aging state evaluation method of crimping type IGBT device in prior art, cannot effectively characterize different aging mode problem, this method is different from traditional single-index evaluation mode, from turn-on performance, thermal stability and current sharing, select on-state voltage drop, junction temperature fluctuation and current imbalance degree as core characterization parameter.First, the reference characteristic value of healthy device is obtained by power cycle test;Second, test the measured device under the same working condition, calculate the change rate of each parameter;Finally, the characteristic parameter is normalized, the comprehensive evaluation index is constructed and compared with the reference, to judge the aging state of device.This method is suitable for aging monitoring of crimping type IGBT device in power electronic device, can provide technical support for device health assessment, guarantee the stable operation of power electronic system.

Description

Technical Field

[0001] This invention relates to the field of condition monitoring technology for press-fit IGBT devices, and specifically to a method for assessing the fretting wear and aging condition of press-fit IGBT devices. Background Technology

[0002] Press-fit IGBT devices possess advantages such as high voltage withstand capability, strong current carrying capacity, and double-sided heat dissipation, making them suitable for high-power applications such as flexible DC transmission converter valves and DC circuit breakers. Their operational reliability directly affects the safe and stable operation of flexible DC transmission systems. However, due to the special packaging structure of press-fit IGBT devices, temperature and pressure distribution become key parameters affecting their reliability. To cope with the rapid development of my country's power grid, while the voltage level and current carrying capacity of IGBT devices are continuously increasing, higher requirements are also being placed on the reliability of device operation. Condition monitoring technology is one of the core means of understanding the health status of IGBT modules, reflecting the device's condition by monitoring its characteristic parameters. Currently, the evaluation indicators for IGBT devices are all for soldered IGBTs; there is still a lack of aging failure standards for press-fit IGBTs. Therefore, it is necessary to explore the impact of aging on different dimensions of operating parameters of press-fit IGBT devices, and to formulate aging evaluation indicators for press-fit IGBTs to monitor device status in a timely manner, thereby improving device reliability and ensuring the safe and reliable operation of my country's power system. Summary of the Invention

[0003] To address the issue that the aging evaluation characteristics of press-fit IGBT devices cannot be directly applied to those of soldered IGBT devices due to significant differences in their packaging structures, and that existing research still lacks an aging evaluation system specifically for press-fit devices, this invention proposes a comprehensive evaluation index for the fretting wear aging of press-fit IGBT devices that comprehensively considers the device's conduction performance, thermal stability, and current sharing.

[0004] The technical solution adopted in this invention is as follows: A multi-dimensional evaluation index for the fretting wear aging state of press-fit IGBT devices is proposed. The main steps are as follows: 1) Power cycling tests are performed on press-fit IGBT devices in a healthy state to extract the on-state voltage drop, the average junction temperature fluctuation value representing the chip, and the current imbalance to determine the baseline characteristic parameters of healthy devices; 2) The operating status of press-fit IGBT devices is monitored in a timely manner, and power cycling tests are performed on the devices periodically to monitor and extract the characteristic parameters of the devices under the current state; 3) The on-state voltage drop change rate, junction temperature fluctuation change rate, and current imbalance of press-fit IGBT devices under different states are normalized to calculate the comprehensive evaluation index for fretting wear aging and to determine the aging state of the devices. Attached Figure Description

[0005] Figure 1This is a multiphysics coupling diagram of a press-fit IGBT.

[0006] Figure 2 This is a simulation model diagram of the TG1500SW45YB-P200 model press-fit IGBT device.

[0007] Figure 3 These are characteristic parameter diagrams of a representative chip for a health device, where: (a) is a junction temperature change curve, and (b) is a current change curve.

[0008] Figure 4 This is a comparison chart of the rate of change of characteristic parameters under different aging states. Detailed Implementation The following detailed description, in conjunction with the accompanying drawings, further elaborates on the "Method for Evaluating the Micro-motion Wear and Aging Status of a Press-fit IGBT Device" proposed in this invention through a specific example.

[0009] Step 1) Select the TG1500SW45YB-P200 model press-fit IGBT device for simulation analysis. First, build a multi-physics coupling simulation model of the device based on the multi-physics coupling relationship of the press-fit IGBT device, see... Figure 1 , Figure 2 Subsequently, a second-level power cycling simulation analysis was conducted on the healthy-state device. Under the condition that each contact surface maintained its initial roughness parameters, the characteristic parameter distribution of the press-fit IGBT device in the healthy state was observed, such as... Figure 3 The characteristic parameters were extracted and are shown in Table 1. It can be seen that the press-fit IGBT device in a healthy state has a slight uneven temperature distribution, but this does not have a significant impact on the electrical characteristics of the device.

[0010] Table 1. Baseline characteristic parameters of health devices

[0011] Step 2) By changing the roughness parameters of each contact surface of each chip within the device, the aging of the press-fit IGBT device is simulated to varying degrees. Power cycling tests are performed on the devices under different aging conditions to monitor and extract characteristic parameters of the devices under different conditions. Simultaneously, a current sharing evaluation index—device current imbalance—is defined.

[0012] In the formula, This is the maximum current in the IGBT chip. This is the minimum current in the IGBT chip. This represents the average current value of all chips within the device. Similarly, the junction temperature fluctuation rate is defined. :

[0013] In the formula, For healthy temperature fluctuations, This represents the current junction temperature fluctuation of the device, and the rate of change of the on-state voltage drop. ):

[0014] In the formula, For a healthy state, conduction voltage drop, This represents the on-state voltage drop of the current device.

[0015] Plot a comparison of the rate of change of various characteristic parameters under different aging states, such as... Figure 4 As shown in the figure, during the fretting wear aging process, the current distribution among the parallel chips gradually becomes unbalanced, leading to a redistribution of the heat load among the chips, ultimately resulting in a decrease in the overall conduction performance of the device. All three types of characteristic parameters exhibit good responsiveness to fretting wear aging in press-fit IGBT devices. Furthermore, the sensitivity of these three characteristic parameters to fretting wear aging states follows the order: junction temperature fluctuation > current imbalance > on-state voltage drop.

[0016] Step 3) To achieve multi-dimensional characterization of device aging, the on-state voltage drop change rate, junction temperature fluctuation change rate, and current imbalance are selected as the core characteristic parameters of fretting wear aging of press-fit IGBT devices. The characteristic parameters of press-fit IGBT devices under different aging states are normalized, and the fretting wear aging comprehensive evaluation index (Aging Degree Index, ADI) is calculated.

[0017]

[0018] in,

[0019] In the formula, These are the normalized rate of change of voltage drop, the rate of change of junction temperature fluctuation, and the current imbalance, respectively. These are the corresponding weighting coefficients.

[0020] To achieve a comprehensive evaluation of all indicators, only an example using equal weighting is provided here:

[0021] Based on the variation patterns of various characteristic parameters at different aging stages, ADI is used as a comprehensive criterion for classifying the aging status of press-fit IGBT devices, dividing them into four intervals: healthy, mildly aged, moderately aged, and severely aged. This is used to achieve qualitative monitoring of different aging stages, as shown in Table 2. After extracting the device status parameters, its fretting wear aging status can be determined, and it can be determined whether the device needs to be replaced.

[0022] Table 2 Aging Status Grading Ranges for Press-fit IGBT Devices

[0023] Although examples of the present invention have been shown and described above, it is understood that the above examples are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above examples within the scope of the present invention.

Claims

1. A method for evaluating a micro-motion wear aging state of a press-pack IGBT device, characterized by, Includes the following steps: 1) Perform power cycling tests on the press-fit IGBT devices in a healthy state, extract the on-state voltage drop, the average junction temperature fluctuation value representing the chip, and the current imbalance, and determine the baseline characteristic parameters of the healthy devices. 2) Monitor the operating status of the press-fit IGBT device in a timely manner, perform power cycling tests on the device regularly, and monitor and extract the characteristic parameters of the device under the current state; 3) The on-state voltage drop change rate, junction temperature fluctuation change rate and current imbalance of the press-fit IGBT device under different conditions are normalized and the comprehensive evaluation index of fretting wear aging is calculated to realize the multi-dimensional characterization of the fretting wear aging state of the device and judge the aging state of the device.

2. The method for evaluating the fretting wear aging state of a press-fit IGBT device according to claim 1, characterized in that: The on-state voltage drop rate, junction temperature fluctuation rate, and current imbalance were selected as the core characteristic parameters of fretting wear aging of press-fit IGBT devices. The fretting wear aging state of the device was characterized by multi-physical field coupling dimensions.

3. The method for evaluating the fretting wear aging state of a press-fit IGBT device according to claim 1, characterized in that: The definitions of the on-state voltage drop rate, junction temperature fluctuation rate, and current imbalance are as follows: In the formula, For a healthy state, conduction voltage drop, This represents the current on-state voltage drop of the device. In the formula, For healthy temperature fluctuations, This refers to the current junction temperature fluctuation of the device; In the formula, This is the maximum current in the IGBT chip. This is the minimum current in the IGBT chip. This represents the average current value of each chip within the device.

4. The method for evaluating the fretting wear aging state of a press-fit IGBT device according to claim 1, characterized in that: The normalization process maps the three feature parameters to a numerical range of 0 to 1, with each indicator participating in the aging classification based on the degree of change rather than the absolute numerical value.

5. The method for evaluating the fretting wear aging state of a press-fit IGBT device according to claim 1, characterized in that: The comprehensive evaluation index for fretting wear and aging is a weighted sum of the normalized on-state voltage drop change rate, junction temperature fluctuation change rate, and current imbalance. The weighting coefficients can be determined based on test data from different working scenarios.

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