Fatigue damage analysis method of IGBT device under different-frequency alternating current superposition stress

Abstract

The invention relates to the technical field of power electronic device life damage analysis, and particularly provides a fatigue damage analysis method and device for an IGBT device under pilot frequency alternating current superposition stress, and the method comprises the steps: determining a junction temperature curve of the IGBT device based on the total loss of the IGBT device and a diode device in a converter sub-module; carrying out statistics on corresponding parameters of various constant-amplitude thermal loads in a current period on the junction temperature curve by adopting a rain flow counting method; determining the damage degree of the IGBT device based on the corresponding parameters of the various constant-amplitude thermal loads in the current period; wherein the current period is the least common multiple of the periods of the two different-frequency currents, and the corresponding parameters of the various constant-amplitude thermal loads comprise the average value, the amplitude and the cycle index. According to the technical scheme provided by the invention, the converter can be supported to carry out key device fatigue damage analysis and service life management, and the operation and maintenance economy of the converter is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of life damage analysis of power electronic devices, and in particular to a fatigue damage analysis method and device for an IGBT device under heterodyne frequency alternating current superimposed stress. Background Art

[0002] Compared to traditional AC transmission, flexible low-frequency AC transmission boasts a stronger transmission capacity, a longer transmission distance, and flexible control capabilities. Compared to flexible DC transmission, it is more economical within a certain transmission capacity and distance range. Therefore, considering a combination of technical and economic factors, flexible low-frequency systems can meet the needs of efficient aggregation and transmission of medium- and long-distance offshore wind power. The modular multilevel matrix converter (M3C) is currently the most suitable AC converter for high-voltage, high-capacity flexible low-frequency transmission technology. It can directly convert AC power to AC power, achieving AC frequency conversion without the need for rectification and inversion, and exhibits excellent characteristics during the transition between low frequency and industrial frequency.

[0003] In an M3C, the bridge arm current is formed by the superposition of power-frequency and low-frequency sinusoidal currents on the converter's input and output sides. The superposition of these two out-of-frequency currents results in multiple positive and negative transitions within a single cycle, resulting in multiple current extremes and exhibiting characteristics such as non-central symmetry and a prolonged cycle. Furthermore, the bridge arm current waveform varies with the amplitude and phase difference of these two out-of-frequency currents, resulting in different arm current waveforms under different operating conditions or in different bridge arms. This further complicates the junction temperature fluctuations of the IGBTs in the converter submodules, making it impossible to directly extract stress parameters for IGBT fatigue damage analysis, hindering the analysis of IGBT fatigue damage. Summary of the Invention

[0004] In order to overcome the above-mentioned defects, the present invention proposes a fatigue damage analysis method and device for IGBT devices under heterogeneous frequency alternating current superimposed stress.

[0005] In a first aspect, a fatigue damage analysis method for an IGBT device under heterogeneous alternating current superimposed stress is provided. The fatigue damage analysis method for an IGBT device under heterogeneous alternating current superimposed stress comprises:

[0006] Determine the junction temperature curve of the IGBT device based on the total loss of the IGBT device and the diode device in the converter submodule;

[0007] The corresponding parameters of various constant amplitude heat loads within a current cycle are counted on the junction temperature curve using a rain flow counting method;

[0008] determining a degree of damage to the IGBT device based on corresponding parameters of various constant-amplitude thermal loads within the current cycle;

[0009] The current cycle is the least common multiple of the cycles of the two currents with different frequencies, and the corresponding parameters of the various constant amplitude heat loads include: average value, amplitude and number of cycles.

[0010] Preferably, the total loss of the IGBT device is as follows:

[0011] P IGBT =P sw +P con_T

[0012] The total loss of the diode device is as follows:

[0013] P FWD =P rec +P con_D

[0014] In the above formula, P IGBT is the total loss of the IGBT device, P sw P is the switching loss of the IGBT device in one current cycle, con_T is the conduction loss of the IGBT device in one current cycle, P FWD is the total loss of the diode device, P rec P is the reverse recovery loss of the diode in one current cycle. con_D is the conduction loss of the diode in one current cycle.

[0015] Furthermore, the switching loss of the IGBT device in one current cycle is as follows:

[0016]

[0017] The reverse recovery loss of the diode in one current cycle is as follows:

[0018]

[0019] In the above formula, V dc is the capacitor voltage of the converter submodule, V CEN is the rated voltage of the IGBT device, T is the current cycle, f s is the number of device switches in one current cycle, E sw is the switching energy curve of the IGBT device, V DN is the rated voltage of the diode, E rec is the reverse recovery energy curve of the diode.

[0020] Furthermore, the conduction loss of the IGBT device in one current cycle is as follows:

[0021]

[0022] The conduction loss of the diode in one current cycle is as follows:

[0023]

[0024] In the above formula, Θ is the actual conduction time of the device, V CE (t) is the output characteristic of the IGBT device at time t, I C (t) is the current of the IGBT device at time t, δ(t) is the device pulse function value at time t, V F (t) is the forward conduction characteristic curve of the diode at time t, I F (t) is the current of the diode at time t.

[0025] Furthermore, the output characteristics of the IGBT device at time t are as follows:

[0026] V CE (t) = R T I C (t)+V 0T

[0027] The forward conduction characteristic curve of the diode at time t is as follows:

[0028] V F (t) = R D I F (t)+V 0D

[0029] In the above formula, R T IGBT is the on-state resistance of the IGBT device, V 0T is the threshold voltage for IGBT device to turn on, R D is the diode slope resistance, V 0D is the threshold voltage for the diode to conduct.

[0030] Furthermore, the junction temperature curve of the IGBT device is as follows:

[0031] T IGBT_j =P IGBT ·(Z jc +Z ch )+(P IGBT +P FWD )·Z ha +T a

[0032] In the above formula, T IGBT_j is the junction temperature curve of the IGBT device, Z jc is the junction-to-case thermal resistance of the IGBT device, Z ch is the case-heat sink thermal resistance of the IGBT device, Z ha is the thermal resistance between the heat sink and the environment, Ta is the ambient temperature.

[0033] Preferably, the damage degree of the IGBT device is as follows:

[0034]

[0035] In the above formula, D is the damage degree of IGBT device, m is the number of constant amplitude thermal load types obtained by rain flow counting, and n is i is the number of cycles of the i-th type constant amplitude heat load, N f_i is the remaining number of cycles of the i-th type constant amplitude heat load.

[0036] Furthermore, the remaining number of cycles of the i-th type constant amplitude heat load is as follows:

[0037]

[0038] In the above formula, △T j_i is the amplitude of the i-th type constant amplitude heat load, A is the first device characteristic parameter, α is the second device characteristic parameter, E a is the excitation energy of the silicon chip, K is the Boltzmann constant, T m_i is the average value of the i-th type constant amplitude heat load, and e is a natural constant.

[0039] Furthermore, A=302500 (Kelvin), a=-5.039.

[0040] In a second aspect, a fatigue damage analysis device for an IGBT device under a stress of a heterogeneous alternating current is provided. The fatigue damage analysis device for an IGBT device under a stress of a heterogeneous alternating current is provided, comprising:

[0041] A first determining module is configured to determine a junction temperature curve of the IGBT device based on the total loss of the IGBT device and the diode device in the converter submodule;

[0042] A statistical module, configured to use a rain flow counting method to calculate corresponding parameters of various constant amplitude heat loads within a current cycle on the junction temperature curve;

[0043] a second determining module, configured to determine a degree of damage to the IGBT device based on corresponding parameters of various constant-amplitude thermal loads within the current cycle;

[0044] The current cycle is the least common multiple of the cycles of the two currents with different frequencies, and the corresponding parameters of the various constant amplitude heat loads include: average value, amplitude and number of cycles.

[0045] Preferably, the total loss of the IGBT device is as follows:

[0046] P IGBT =Psw +P con_T

[0047] The total loss of the diode device is as follows:

[0048] P FWD =P rec +P con_D

[0049] In the above formula, P IGBT is the total loss of the IGBT device, P sw P is the switching loss of the IGBT device in one current cycle, con_T is the conduction loss of the IGBT device in one current cycle, P FWD is the total loss of the diode device, P rec P is the reverse recovery loss of the diode in one current cycle. con_D is the conduction loss of the diode in one current cycle.

[0050] Furthermore, the switching loss of the IGBT device in one current cycle is as follows:

[0051]

[0052] The reverse recovery loss of the diode in one current cycle is as follows:

[0053]

[0054] In the above formula, V dc is the capacitor voltage of the converter submodule, V CEN is the rated voltage of the IGBT device, T is the current cycle, f s is the number of device switches in one current cycle, E sw is the switching energy curve of the IGBT device, V DN is the rated voltage of the diode, E rec is the reverse recovery energy curve of the diode.

[0055] Furthermore, the conduction loss of the IGBT device in one current cycle is as follows:

[0056]

[0057] The conduction loss of the diode in one current cycle is as follows:

[0058]

[0059] In the above formula, Θ is the actual conduction time of the device, V CE (t) is the output characteristic of the IGBT device at time t, IC (t) is the current of the IGBT device at time t, δ(t) is the device pulse function value at time t, V F (t) is the forward conduction characteristic curve of the diode at time t, I F (t) is the current of the diode at time t.

[0060] Furthermore, the output characteristics of the IGBT device at time t are as follows:

[0061] V CE (t) = R T I C (t)+V 0T

[0062] The forward conduction characteristic curve of the diode at time t is as follows:

[0063] V F (t) = R D I F (t)+V 0D

[0064] In the above formula, R T IGBT is the on-state resistance of the IGBT device, V 0T is the threshold voltage for IGBT device to turn on, R D is the diode slope resistance, V 0D is the threshold voltage for the diode to conduct.

[0065] Furthermore, the junction temperature curve of the IGBT device is as follows:

[0066] T IGBT_j =P IGBT ·(Z jc +Z ch )+(P IGBT +P FWD )·Z ha +T a

[0067] In the above formula, T IGBT_j is the junction temperature curve of the IGBT device, Z jc is the junction-to-case thermal resistance of the IGBT device, Z ch is the case-heat sink thermal resistance of the IGBT device, Z ha is the thermal resistance between the heat sink and the environment, T a is the ambient temperature.

[0068] Preferably, the damage degree of the IGBT device is as follows:

[0069]

[0070] In the above formula, D is the damage degree of IGBT device, m is the number of constant amplitude thermal load types obtained by rain flow counting, and n is i is the number of cycles of the i-th type constant amplitude heat load, N f_i is the remaining number of cycles of the i-th type constant amplitude heat load.

[0071] Furthermore, the remaining number of cycles of the i-th type constant amplitude heat load is as follows:

[0072]

[0073] In the above formula, △T j_i is the amplitude of the i-th type constant amplitude heat load, A is the first device characteristic parameter, α is the second device characteristic parameter, E a is the excitation energy of the silicon chip, K is the Boltzmann constant, T m_i is the average value of the i-th type constant amplitude heat load, and e is a natural constant.

[0074] Furthermore, A=302500 (Kelvin), a=-5.039.

[0075] In a third aspect, a computer device is provided, comprising: one or more processors;

[0076] The processor is configured to execute one or more programs;

[0077] When the one or more programs are executed by the one or more processors, the fatigue damage analysis method of the IGBT device under the heterodyne alternating current superimposed stress is implemented.

[0078] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed, the fatigue damage analysis method of the IGBT device under the heterodyne alternating current superimposed stress is implemented.

[0079] The above one or more technical solutions of the present invention have at least one or more of the following beneficial effects:

[0080] The present invention provides a fatigue damage analysis method and device for IGBT devices under the stress of superimposed heterofrequency alternating current, comprising: determining the junction temperature curve of the IGBT device based on the total loss of the IGBT device and diode device in the converter submodule; using the rain flow counting method to count the corresponding parameters of various constant amplitude thermal loads within a current cycle on the junction temperature curve; and determining the damage degree of the IGBT device based on the corresponding parameters of various constant amplitude thermal loads within the current cycle; wherein the current cycle is the least common multiple of the cycles of two heterofrequency currents, and the corresponding parameters of the various constant amplitude thermal loads include: average value, amplitude, and number of cycles. The technical solution provided by the present invention can more accurately analyze the submodule IGBT junction temperature fluctuation characteristics and fatigue damage caused by the superposition of two different frequency alternating currents in a modular multi-level matrix converter, thereby supporting the converter to carry out fatigue damage analysis and life management of key components, and improving the economic efficiency of converter operation and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 It is a flow chart of the main steps of the fatigue damage analysis method of an IGBT device under heterodyne frequency alternating current superimposed stress according to an embodiment of the present invention. DETAILED DESCRIPTION

[0082] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0083] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0084] As disclosed in the background technology, flexible low-frequency AC transmission has a stronger transmission capacity and a longer transmission limit distance than traditional AC transmission, and has flexible control capabilities; compared with flexible DC transmission, it is more economical within a certain transmission capacity and distance range. Therefore, considering comprehensive factors such as technology and economy, the flexible low-frequency system can meet the needs of efficient collection and transmission of medium and long-distance offshore wind power. The modular multi-level matrix converter (M3C) is an AC converter that is currently more suitable for high-voltage and large-capacity flexible low-frequency transmission technology. It can directly convert AC power into AC power, and can achieve AC frequency conversion without first going through the rectification and then inversion links. It has good characteristics in the low-frequency and industrial frequency conversion process.

[0085] In an M3C, the bridge arm current is formed by the superposition of power-frequency and low-frequency sinusoidal currents on the converter's input and output sides. The superposition of these two out-of-frequency currents results in multiple positive and negative transitions within a single cycle, resulting in multiple current extremes and exhibiting characteristics such as non-central symmetry and a prolonged cycle. Furthermore, the bridge arm current waveform varies with the amplitude and phase difference of these two out-of-frequency currents, resulting in different arm current waveforms under different operating conditions or in different bridge arms. This further complicates the junction temperature fluctuations of the IGBTs in the converter submodules, making it impossible to directly extract stress parameters for IGBT fatigue damage analysis, hindering the analysis of IGBT fatigue damage.

[0086] To improve the above-mentioned problems, the present invention provides a fatigue damage analysis method and apparatus for IGBT devices under the stress of heterogeneous alternating current superposition, comprising: determining the junction temperature curve of the IGBT device based on the total loss of the IGBT device and the diode device in the converter submodule; using the rain flow counting method to count the corresponding parameters of various constant amplitude thermal loads within a current cycle on the junction temperature curve; and determining the damage degree of the IGBT device based on the corresponding parameters of various constant amplitude thermal loads within the current cycle; wherein the current cycle is the least common multiple of the cycles of the two heterogeneous currents, and the corresponding parameters of the various constant amplitude thermal loads include: average value, amplitude, and number of cycles. The technical solution provided by the present invention can more accurately analyze the junction temperature fluctuation characteristics and fatigue damage of the submodule IGBT caused by the superposition of two different frequency alternating currents in a modular multi-level matrix converter, thereby supporting the converter to carry out fatigue damage analysis and life management of key components, and improving the economic efficiency of converter operation and maintenance.

[0087] The above scheme is described in detail below.

[0088] Example 1

[0089] See attached Figure 1 , Figure 1 FIG1 is a flow chart showing the main steps of a fatigue damage analysis method for an IGBT device under a stress of a different frequency alternating current. Figure 1 As shown, the fatigue damage analysis method of the IGBT device under the stress of the alternating current with different frequencies in the embodiment of the present invention mainly includes the following steps:

[0090] Step S101: determining a junction temperature curve of an IGBT device based on the total loss of the IGBT device and the diode device in the converter submodule;

[0091] Step S102: using a rain flow counting method to collect statistics on corresponding parameters of various constant amplitude heat loads within a current cycle on the junction temperature curve;

[0092] Step S103: determining the damage degree of the IGBT device based on corresponding parameters of various constant amplitude thermal loads within the current cycle;

[0093] The current cycle is the least common multiple of the cycles of the two currents with different frequencies, and the corresponding parameters of the various constant amplitude heat loads include: average value, amplitude and number of cycles.

[0094] In this embodiment, the total loss of the IGBT device is as follows:

[0095] P IGBT =P sw +P con_T

[0096] The total loss of the diode device is as follows:

[0097] P FWD =P rec +P con_D

[0098] In the above formula, P IGBT is the total loss of the IGBT device, P sw P is the switching loss of the IGBT device in one current cycle, con_T is the conduction loss of the IGBT device in one current cycle, P FWD is the total loss of the diode device, P rec P is the reverse recovery loss of the diode in one current cycle. con_D is the conduction loss of the diode in one current cycle.

[0099] In one embodiment, the switching loss of the IGBT device in one current cycle is as follows:

[0100]

[0101] The reverse recovery loss of the diode in one current cycle is as follows:

[0102]

[0103] In the above formula, V dc is the capacitor voltage of the converter submodule, V CEN is the rated voltage of the IGBT device, T is the current cycle, f s is the number of device switches in one current cycle, E sw is the switching energy curve of the IGBT device, V DN is the rated voltage of the diode, E rec is the reverse recovery energy curve of the diode.

[0104] In a specific embodiment, the switching energy curve of the IGBT device can be obtained by fitting a quadratic polynomial based on the switching energy curve provided in the IGBT device data sheet:

[0105] E sw =a1I C (t) 2 +b1I C (t)+c1

[0106] The diode turn-on loss is generally negligible, and its reverse recovery energy curve is fitted with a quadratic polynomial to obtain:

[0107] E rec =a2I F (t) 2 +b2I F (t)+c2

[0108] In the above formula, a1, b1, c1, a2, b2, and c2 are all fitting coefficients.

[0109] In one embodiment, the conduction loss of the IGBT device in one current cycle is as follows:

[0110]

[0111] The conduction loss of the diode in one current cycle is as follows:

[0112]

[0113] In the above formula, Θ is the actual conduction time of the device, V CE (t) is the output characteristic of the IGBT device at time t, I C (t) is the current of the IGBT device at time t, δ(t) is the device pulse function value at time t, V F (t) is the forward conduction characteristic curve of the diode at time t, I F (t) is the current of the diode at time t.

[0114] In one embodiment, the output characteristics of the IGBT device at time t are as follows:

[0115] V CE (t) = R T I C (t)+V 0T

[0116] The forward conduction characteristic curve of the diode at time t is as follows:

[0117] V F (t) = R D I F (t)+V 0D

[0118] In the above formula, R TIGBT is the on-state resistance of the IGBT device, V 0T is the threshold voltage for IGBT device to turn on, R D is the diode slope resistance, V 0D is the threshold voltage for the diode to conduct.

[0119] In one embodiment, the junction temperature curve of the IGBT device is as follows:

[0120] T IGBT_j =P IGBT ·(Z jc +Z ch )+(P IGBT +P FWD )·Z ha +T a

[0121] In the above formula, T IGBT_j is the junction temperature curve of the IGBT device, Z jc is the junction-to-case thermal resistance of the IGBT device, Z ch is the case-heat sink thermal resistance of the IGBT device, Z ha is the thermal resistance between the heat sink and the environment, T a is the ambient temperature.

[0122] In this embodiment, the damage degree of the IGBT device is as follows:

[0123]

[0124] In the above formula, D is the damage degree of IGBT device, m is the number of constant amplitude thermal load types obtained by rain flow counting, and n is i is the number of cycles of the i-th type constant amplitude heat load, N f_i is the remaining number of cycles of the i-th type constant amplitude heat load.

[0125] In one embodiment, the remaining number of cycles of the i-th type constant amplitude heat load is as follows:

[0126]

[0127] In the above formula, △T j_i is the amplitude of the i-th type constant amplitude heat load, A is the first device characteristic parameter, α is the second device characteristic parameter, E a is the excitation energy of the silicon chip, K is the Boltzmann constant, T m_i is the average value of the i-th type constant amplitude heat load, and e is a natural constant.

[0128] Wherein, A=302500 (Kelvin), a=-5.039.

[0129] Example 2

[0130] Based on the same inventive concept, the present invention further provides a fatigue damage analysis device for an IGBT device under heterogeneous alternating current superimposed stress, the fatigue damage analysis device for an IGBT device under heterogeneous alternating current superimposed stress comprising:

[0131] A first determining module is configured to determine a junction temperature curve of the IGBT device based on the total loss of the IGBT device and the diode device in the converter submodule;

[0132] A statistical module, configured to use a rain flow counting method to calculate corresponding parameters of various constant amplitude heat loads within a current cycle on the junction temperature curve;

[0133] a second determining module, configured to determine a degree of damage to the IGBT device based on corresponding parameters of various constant-amplitude thermal loads within the current cycle;

[0134] The current cycle is the least common multiple of the cycles of the two currents with different frequencies, and the corresponding parameters of the various constant amplitude heat loads include: average value, amplitude and number of cycles.

[0135] Preferably, the total loss of the IGBT device is as follows:

[0136] P IGBT =P sw +P con_T

[0137] The total loss of the diode device is as follows:

[0138] P FWD =P rec +P con_D

[0139] In the above formula, P IGBT is the total loss of the IGBT device, P sw P is the switching loss of the IGBT device in one current cycle, con_T is the conduction loss of the IGBT device in one current cycle, P FWD is the total loss of the diode device, P rec P is the reverse recovery loss of the diode in one current cycle. con_D is the conduction loss of the diode in one current cycle.

[0140] Furthermore, the switching loss of the IGBT device in one current cycle is as follows:

[0141]

[0142] The reverse recovery loss of the diode in one current cycle is as follows:

[0143]

[0144] In the above formula, V dc is the capacitor voltage of the converter submodule, V CEN is the rated voltage of the IGBT device, T is the current cycle, f s is the number of device switches in one current cycle, E sw is the switching energy curve of the IGBT device, V DN is the rated voltage of the diode, E rec is the reverse recovery energy curve of the diode.

[0145] Furthermore, the conduction loss of the IGBT device in one current cycle is as follows:

[0146]

[0147] The conduction loss of the diode in one current cycle is as follows:

[0148]

[0149] In the above formula, Θ is the actual conduction time of the device, V CE (t) is the output characteristic of the IGBT device at time t, I C (t) is the current of the IGBT device at time t, δ(t) is the device pulse function value at time t, V F (t) is the forward conduction characteristic curve of the diode at time t, I F (t) is the current of the diode at time t.

[0150] Furthermore, the output characteristics of the IGBT device at time t are as follows:

[0151] V CE (t) = R T I C (t)+V 0T

[0152] The forward conduction characteristic curve of the diode at time t is as follows:

[0153] V F (t) = R D I F (t)+V 0D

[0154] In the above formula, R T IGBT is the on-state resistance of the IGBT device, V 0T is the threshold voltage for IGBT device to turn on, R D is the diode slope resistance, V 0D is the threshold voltage for the diode to conduct.

[0155] Furthermore, the junction temperature curve of the IGBT device is as follows:

[0156] T IGBT_j =P IGBT ·(Z jc +Z ch )+(P IGBT +P FWD )·Z ha +T a

[0157] In the above formula, T IGBT_j is the junction temperature curve of the IGBT device, Z jc is the junction-to-case thermal resistance of the IGBT device, Z ch is the case-heat sink thermal resistance of the IGBT device, Z ha is the thermal resistance between the heat sink and the environment, T a is the ambient temperature.

[0158] Preferably, the damage degree of the IGBT device is as follows:

[0159]

[0160] In the above formula, D is the damage degree of IGBT device, m is the number of constant amplitude thermal load types obtained by rain flow counting, and n is i is the number of cycles of the i-th type constant amplitude heat load, N f_i is the remaining number of cycles of the i-th type constant amplitude heat load.

[0161] Furthermore, the remaining number of cycles of the i-th type constant amplitude heat load is as follows:

[0162]

[0163] In the above formula, △T j_i is the amplitude of the i-th type constant amplitude heat load, A is the first device characteristic parameter, α is the second device characteristic parameter, E a is the excitation energy of the silicon chip, K is the Boltzmann constant, T m_i is the average value of the i-th type constant amplitude heat load, and e is a natural constant.

[0164] Furthermore, A=302500 (Kelvin), a=-5.039.

[0165] Example 3

[0166] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, the memory being used to store a computer program, the computer program including program instructions, and the processor being used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of the fatigue damage analysis method of an IGBT device under heterodyne alternating current superimposed stress in the above embodiment.

[0167] Example 4

[0168] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It can be understood that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space. These instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of a fatigue damage analysis method for an IGBT device under heterodyne alternating current superimposed stress in the above embodiment.

[0169] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0170] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0171] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0172] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A fatigue damage analysis method for IGBT devices under heterodyne alternating current superimposed stress, characterized in that: The method comprises: Determine a junction temperature curve of the IGBT device based on the total loss of the IGBT device and the diode device in the converter submodule; The corresponding parameters of various constant amplitude heat loads within a current cycle are counted for the junction temperature curve using a rain flow counting method; Determining the degree of damage of the IGBT device based on corresponding parameters of various constant amplitude thermal loads within the one current cycle; The one current cycle is the least common multiple of the cycles of two currents with different frequencies, and the corresponding parameters of the various constant amplitude heat loads include: average value, amplitude and number of cycles.

2. The method according to claim 1, characterized in that The total loss of the IGBT device is as follows: P IGBT =P sw +P con_T The total loss of the diode device is as follows: P FWD =P rec +P con_D In the above formula, P IGBT is the total loss of the IGBT device, P sw P is the switching loss of the IGBT device in one current cycle. con_T is the conduction loss of the IGBT device in one current cycle, P FWD is the total loss of the diode device, P rec P is the reverse recovery loss of the diode in one current cycle. con_D is the conduction loss of the diode in one current cycle.

3. The method according to claim 2, characterized in that The switching loss of the IGBT device in one current cycle is as follows: The reverse recovery loss of the diode in one current cycle is as follows: In the above formula, V dc is the converter submodule capacitor voltage, V CEN is the rated voltage of the IGBT device, T is the current cycle, f s is the number of device switching times in one current cycle, E sw is the switching energy curve of the IGBT device, V DN is the rated voltage of the diode, E rec is the reverse recovery energy curve of the diode.

4. The method according to claim 3, characterized in that The conduction loss of the IGBT device in one current cycle is as follows: The conduction loss of the diode in one current cycle is as follows: In the above formula, Θ is the actual conduction time of the device, V CE (t) is the output characteristic of the IGBT device at time t, I C (t) is the current of the IGBT device at time t, δ(t) is the device pulse function value at time t, V F (t) is the forward conduction characteristic curve of the diode at time t, I F (t) is the current of the diode at time t.

5. The method according to claim 4, characterized in that The output characteristics of the IGBT device at time t are as follows: V CE (t)=R T I C (t)+V 0T The forward conduction characteristic curve of the diode at time t is as follows: V F (t)=R D I F (t)+V 0D In the above formula, R T IGBT is the on-state resistance of the IGBT device, V 0T is the threshold voltage for IGBT device to turn on, R D is the diode slope resistance, V 0D is the threshold voltage for the diode to conduct.

6. The method according to claim 2, characterized in that The junction temperature curve of the IGBT device is as follows: T IGBT_j =P IGBT ·(Z jc +Z ch )+(P IGBT +P FWD )·Z ha +T a In the above formula, T IGBT_j is the junction temperature curve of the IGBT device, Z jc is the junction-to-case thermal resistance of the IGBT device, Z ch is the case-heat sink thermal resistance of the IGBT device, Z ha is the thermal resistance between the heat sink and the environment, T a is the ambient temperature.

7. The method according to claim 1, characterized in that The damage degree of the IGBT device is as follows: In the above formula, D is the damage degree of the IGBT device, m is the number of constant amplitude thermal load types obtained by rain flow counting, and n is i is the number of cycles of the i-th type of constant amplitude heat load, N f_i is the remaining number of cycles of the i-th type constant amplitude heat load.

8. The method according to claim 7, characterized in that The remaining number of cycles of the i-th type constant amplitude heat load is as follows: In the above formula, △T j_i is the amplitude of the i-th type of constant amplitude heat load, A is the characteristic parameter of the first device, α is the characteristic parameter of the second device, E a is the excitation energy of the silicon chip, K is the Boltzmann constant, T m_i is the average value of the i-th type constant amplitude heat load, and e is a natural constant.

9. The method according to claim 8, characterized in that Said A=302500 (Kelvin), a=-5.

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10. A fatigue damage analysis device for IGBT devices under heterodyne alternating current superimposed stress, characterized in that: The device comprises: A first determination module is used to determine a junction temperature curve of the IGBT device based on the total loss of the IGBT device and the diode device in the converter submodule; A statistical module, used for using a rain flow counting method to count corresponding parameters of various constant amplitude heat loads within a current cycle on the junction temperature curve; A second determination module is used to determine the damage degree of the IGBT device based on the corresponding parameters of various constant amplitude heat loads in the one current cycle; The one current cycle is the least common multiple of the cycles of two currents with different frequencies, and the corresponding parameters of the various constant amplitude heat loads include: average value, amplitude and number of cycles.

11. The device according to claim 10, characterized in that The total loss of the IGBT device is as follows: P IGBT =P sw +P con_T The total loss of the diode device is as follows: P FWD =P rec +P con_D In the above formula, P IGBT is the total loss of the IGBT device, P sw P is the switching loss of the IGBT device in one current cycle. con_T is the conduction loss of the IGBT device in one current cycle, P FWD is the total loss of the diode device, P rec P is the reverse recovery loss of the diode in one current cycle. con_D is the conduction loss of the diode in one current cycle.

12. The device according to claim 11, characterized in that The switching loss of the IGBT device in one current cycle is as follows: The reverse recovery loss of the diode in one current cycle is as follows: In the above formula, V dc is the converter submodule capacitor voltage, V CEN is the rated voltage of the IGBT device, T is the current cycle, f s is the number of device switching times in one current cycle, E sw is the switching energy curve of the IGBT device, V DN is the rated voltage of the diode, E rec is the reverse recovery energy curve of the diode.

13. The device according to claim 12, characterized in that The conduction loss of the IGBT device in one current cycle is as follows: The conduction loss of the diode in one current cycle is as follows: In the above formula, Θ is the actual conduction time of the device, V CE (t) is the output characteristic of the IGBT device at time t, I C (t) is the current of the IGBT device at time t, δ(t) is the device pulse function value at time t, V F (t) is the forward conduction characteristic curve of the diode at time t, I F (t) is the current of the diode at time t.

14. The device according to claim 13, characterized in that The output characteristics of the IGBT device at time t are as follows: V CE (t)=R T I C (t)+V 0T The forward conduction characteristic curve of the diode at time t is as follows: V F (t)=R D I F (t)+V 0D In the above formula, R T IGBT is the on-state resistance of the IGBT device, V 0T is the threshold voltage for IGBT device to turn on, R D is the diode slope resistance, V 0D is the threshold voltage for the diode to conduct.

15. The device according to claim 11, characterized in that The junction temperature curve of the IGBT device is as follows: T IGBT_j =P IGBT ·(Z jc +Z ch )+(P IGBT +P FWD )·Z ha +T a In the above formula, T IGBT_j is the junction temperature curve of the IGBT device, Z jc is the junction-to-case thermal resistance of the IGBT device, Z ch is the case-heat sink thermal resistance of the IGBT device, Z ha is the thermal resistance between the heat sink and the environment, T a is the ambient temperature.

16. The device according to claim 10, characterized in that The damage degree of the IGBT device is as follows: In the above formula, D is the damage degree of the IGBT device, m is the number of constant amplitude thermal load types obtained by rain flow counting, and n is i is the number of cycles of the i-th type of constant amplitude heat load, N f_i is the remaining number of cycles of the i-th type constant amplitude heat load.

17. The device according to claim 16, characterized in that The remaining number of cycles of the i-th type constant amplitude heat load is as follows: In the above formula, △T j_i is the amplitude of the i-th type of constant amplitude heat load, A is the characteristic parameter of the first device, α is the characteristic parameter of the second device, E a is the excitation energy of the silicon chip, K is the Boltzmann constant, T m_i is the average value of the i-th type constant amplitude heat load, and e is a natural constant.

18. The device according to claim 17, characterized in that Said A=302500 (Kelvin), a=-5.

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19. A computer device, characterized in that: include: one or more processors; The processor is configured to execute one or more programs; When the one or more programs are executed by the one or more processors, the fatigue damage analysis method of an IGBT device under heterodyne alternating current superimposed stress as described in any one of claims 1 to 9 is implemented.

20. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the fatigue damage analysis method of an IGBT device under heterodyne frequency alternating current superimposed stress as claimed in any one of claims 1 to 9 is implemented.

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