A method and system for monitoring the aging of IGBT half-bridge circuits

Abstract

This invention relates to the field of power semiconductor device monitoring technology, and discloses an aging monitoring method and system for IGBT half-bridge circuits. This method can realistically simulate the working state of IGBT half-bridge circuits under normal and aging conditions, providing a basis for aging modeling of more complex circuit systems containing IGBT half-bridge circuits; it can comprehensively simulate the nonlinear transient characteristics of IGBT modules, and can obtain aging data and characteristics of IGBT modules without physical damage experiments; this method can be extended to aging modeling of other different bridge circuits.

Description

Technical Field

[0001] This invention relates to the field of power semiconductor device monitoring technology, and in particular to an aging monitoring method and system for IGBT half-bridge circuits. Background Technology

[0002] The smallest packaged unit (IGBT module) composed of an Insulated Gate Bipolar Transistor (IGBT) and a freewheeling diode is an irreplaceable fundamental product, widely used in the production and manufacturing of power installations at the bridge circuit level, converter device level, converter system level, and various energy and transmission system levels. As power installations age, certain performance indicators of IGBT modules will degrade, leading to aging and failure. If these issues are not detected and addressed promptly, they can easily cause short circuits, open circuits, device burnout or explosion, and even lead to the failure of the entire power installation.

[0003] The IGBT half-bridge circuit is the simplest bridge circuit containing IGBT modules. This study investigates its aging mechanism, characteristics, and aging modeling methods, providing a more realistic aging simulation environment for IGBT half-bridge circuits. This facilitates the monitoring of IGBT half-bridge circuit aging and provides a foundation for aging modeling of more complex circuit systems. It is of great significance for improving the performance, safe operation, and operational capability of power installations.

[0004] Existing research on IGBT module aging techniques mostly rely on parameter evaluation based on the sensitive parameters of the IGBT itself to predict aging lifespan. However, these techniques do not consider the switching transient process of the aged IGBT module, nor do they take into account the aging characteristics of more complex circuit systems such as IGBT half-bridge circuits. Therefore, they are insufficient to meet the simulation requirements for IGBT aging detection, diagnosis, isolation, and fault tolerance in various power devices.

[0005] Therefore, there is an urgent need to provide a method that can improve the realism and effectiveness of aging process simulation of IGBT half-bridge circuits in order to achieve aging monitoring. Summary of the Invention

[0006] This invention provides a method and system for monitoring the aging of IGBT half-bridge circuits to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] In a first aspect, the present invention provides a method for monitoring the aging of an IGBT half-bridge circuit, characterized in that it includes:

[0009] S1: Obtain the transient electrical characteristics of the IGBT module when the IGBT half-bridge circuit is turned on and off, and construct a nonlinear transient model of the IGBT module based on the transient electrical characteristics;

[0010] S2: Determine the commutation loop characteristics of the IGBT half-bridge circuit based on the nonlinear transient model of the IGBT module;

[0011] S3: Construct the model parameter set. Based on the characteristics of the IGBT half-bridge circuit commutation loop and the model parameter set, construct the electrical model of the IGBT half-bridge circuit.

[0012] S4: Establish the relationship between the model parameters of the IGBT half-bridge circuit electrical model and the aging type of the IGBT module, the aging degree of the IGBT and the freewheeling diode;

[0013] S5: Construct an electrical model of the IGBT half-bridge circuit under aging conditions based on the IGBT half-bridge circuit electrical model and the aforementioned relationship, and monitor the aging condition of the IGBT half-bridge circuit based on the electrical model under aging conditions.

[0014] Optionally, the transient electrical characteristics of the IGBT module when the IGBT half-bridge circuit is turned on are obtained in step S1 as follows:

[0015] At time t0, the IGBT receives the turn-on command, and the gate drive voltage V... g The output is 15V, the IGBT is operating in the cutoff region, the freewheeling diode is on, and the gate-emitter voltage of the IGBT is v. ge The voltage rises, but remains below the gate-emitter threshold voltage V at which the IGBT turns on. ge(th) The freewheeling diode current i d Decrease, collector-emitter current i c rise;

[0016] At time t1, the gate-emitter voltage v of the IGBT ge The gate-emitter threshold voltage V rises to the IGBT conduction point ge(th) When the IGBT enters the active region, the collector-emitter voltage v ce The gate-emitter voltage v begins to decrease. ge The freewheeling diode current i continues to rise. d The collector-emitter current i continues to decrease. c Continued to rise;

[0017] At time t2, the freewheeling diode current i d The decline reached its negative peak. K is the reverse recovery current coefficient. The voltage across the control inductor is reduced to the reverse recovery current, causing the freewheeling diode to turn off, and the collector-emitter voltage v ce Continuously decreasing; gate-emitter voltage vge Entering the Miller plateau, the freewheeling diode current i d Reverse recovery from negative peak value, collector-emitter current i c Decrease from the maximum value;

[0018] At time t3, the collector-emitter voltage v of the IGBT ce The pressure drop decreases to the saturation voltage V cesat When the IGBT enters the saturation region, the collector-emitter voltage V... ce The voltage decreases and tends towards a steady-state turn-on; the gate-emitter voltage v ge Rising and trending towards the gate drive voltage V g The freewheeling diode current i d Continuous reverse recovery, collector-emitter current i c It is declining and trending towards an open steady state;

[0019] At time t4, the values ​​of all IGBT variables reach their steady-state values ​​upon turn-on.

[0020] The transient electrical characteristics of the IGBT module when the IGBT half-bridge circuit is turned off are as follows:

[0021] At time t5, the IGBT receives a turn-off command, and the gate drive voltage V... g The output is 0V, the IGBT is operating in the saturation region, the freewheeling diode is off, and the gate-emitter voltage of the IGBT is v. ge It decreases, but is still greater than the sustaining load current I. L Minimum value V of the gate-emitter voltage flowing through the IGBT ge(pl) ;

[0022] At time t6, the gate-emitter voltage v of the IGBT ge Drop to sustaining load current I L Minimum value V of the gate-emitter voltage flowing through the IGBT ge(pl) When the IGBT enters the active region, the collector-emitter voltage v ce Rise, gate-emitter voltage v ge Enter the Miller platform;

[0023] At time t7, the collector-emitter voltage v of the IGBT ce Rise to DC side voltage V cap The forward voltage drop V of an ideal diode d(on) The sum of the values ​​of the freewheeling diodes leads to the diodes being switched on, and the collector-emitter voltage V... ce The gate-emitter voltage continues to rise to a peak voltage and then falls, v ge Decrease, collector-emitter current i c decline;

[0024] At time t8, the gate-emitter voltage v of the IGBT ge The gate-emitter threshold voltage V drops to the IGBT conduction point.ge(th) When the IGBT enters the cutoff region, the freewheeling diode is in the on state, and the collector-emitter voltage V... ce The gate-emitter voltage v decreases and tends towards a turn-off steady state. ge Decrease and tend towards the gate drive voltage V g collector-emitter current i c It is decreasing and trending towards a steady-state of shutdown;

[0025] At time t9, the values ​​of all IGBT variables reach their turn-off steady-state values.

[0026] Optionally, in S1, the nonlinear transient model of the IGBT module when the IGBT is turned on satisfies the following relationship:

[0027]

[0028] Where d is the differential of the subsequent variable, R g It is the stray resistance of the IGBT gate; C ge It is the parasitic capacitance between the gate and emitter of the IGBT; C cg It is the parasitic capacitance between the collector and gate of the IGBT; C ce It is the parasitic capacitance between the collector and emitter of the IGBT; R g It is the stray resistance of the IGBT gate; L σ V is the parasitic inductance of the IGBT collector; k is the equivalent current coefficient flowing through the MOSFET within the IGBT structure; ce(on) It is the forward voltage drop of the IGBT in steady state during turn-on; V cesat It is the saturation voltage drop of the IGBT, I L This is the load current of the IGBT half-bridge circuit; V cap δ is the DC-side voltage of the IGBT half-bridge circuit; δ is an intermediate variable in the model, and δ = (C cg ·C ce +C cg ·C ge +C ge ·C ce ); C ies It is the ideal input capacitor for the IGBT, and C ies =C ge +C cg C oes It is the ideal output capacitor for IGBTs, and C oes =C cg +C ce V ce(off) It is the turn-off steady-state voltage of the collector-emitter voltage, and the formula is:

[0029] V ce(off) =V cap +R don·I L (2)

[0030] In the formula, R don It is the equivalent internal resistance of the freewheeling diode;

[0031] V g It is the IGBT gate drive voltage, and the formula is:

[0032]

[0033] In the formula, V g(on) It is the drive voltage when the IGBT is turned on, V g(off) It is the drive voltage when the IGBT is turned off;

[0034] i d It is the freewheeling diode current, and the formula is:

[0035]

[0036] In the formula, It is the time constant of the reverse recovery phenomenon of the freewheeling diode; current source The reverse recovery phenomenon was simulated, and its value was determined by the first-order reverse recovery current R. rr L rr Circuit control; R rr It is the control resistor for the reverse recovery current; L rr It is the control inductor for the reverse recovery current; K is the reverse recovery current coefficient;

[0037] Among them, formulas (1) to (4) constitute the nonlinear transient model of the IGBT module when the IGBT is turned on;

[0038] The nonlinear transient model of the IGBT module when the IGBT is turned off satisfies the following relationship:

[0039]

[0040] Among them, i tail This is the tail current of the IGBT, and its value is determined by the first-order R of the tail current. tail C tail Circuit control, R tail It is the control resistor for the trailing current; C tail It is the control capacitor for the tail current, and the formula is:

[0041]

[0042] V ge ( pl) Is maintaining load current I L Gate-emitter voltage v flowing through the IGBT ge The minimum value is given by the formula:

[0043]

[0044] Formulas (5) to (7) constitute the nonlinear transient model of the IGBT module when the IGBT is turned off; formulas (1) to (7) constitute the nonlinear transient model of the IGBT module.

[0045] Optionally, S2 includes:

[0046] The input of the IGBT half-bridge circuit is the load current I. L and DC side voltage V cap The output is the upper half-bridge current i. x and midpoint voltage u x Based on the nonlinear transient model of the IGBT module, the characteristics of the IGBT half-bridge circuit commutator loop are described as follows:

[0047]

[0048] Among them, u x It is the midpoint voltage, i x This is the upper half-bridge current. (~()) represents the inversion operation of the binary number within the parentheses; when the value of the binary number within the parentheses is 1, the output is 0; when the value is 0, the output is 1. S T1 This indicates the switching command for power device T1, used to control the IGBT module numbered 1 in the lower half-bridge. T2 This indicates the switching command for power device T2, used to control the IGBT module numbered 2 in the upper half-bridge. T1 and S T2 The value is either 0 or 1 in binary. When the value is 0, it corresponds to a shutdown instruction, and when the value is 1, it corresponds to a startup instruction. and These represent the collector-emitter current and collector-emitter voltage during the turn-on process and the collector-emitter current and collector-emitter voltage during the turn-off process of power device T1, respectively. and Let T2 represent the collector-emitter current and collector-emitter voltage during the turn-on process and the collector-emitter current and collector-emitter voltage during the turn-off process, respectively. The formulas are as follows:

[0049]

[0050] In the formula, i represents the IGBT module number, with values ​​of 1 and 2; c (t) and v ce (t) represents the collector-emitter current and collector-emitter voltage in the nonlinear transient model of the IGBT module constructed in step 1.

[0051] Optionally, the model parameter set constructed in S3 is as follows:

[0052] The parameter set for constructing the electrical model of the IGBT half-bridge circuit is denoted as H, and the elements in the set are the parameter sets G corresponding to the nonlinear transient models of the IGBT modules. i G 1 and G 2 The formula is as follows:

[0053] H = {G i ,i=1,2} (10)

[0054] Among them, the parameter set G of the nonlinear transient model of the IGBT module i The elements within the IGBT include the gate stray resistance, parasitic capacitance between the gate and emitter, parasitic capacitance between the collector and gate, parasitic capacitance between the collector and emitter, tail current control resistor, tail current control capacitor, collector parasitic inductance, gate-emitter threshold voltage, saturation voltage drop, turn-on steady-state forward voltage drop, equivalent current coefficient flowing through the MOSFET within the structure, and the equivalent internal resistance of the freewheeling diode, the time constant of the reverse recovery current, and the reverse recovery current coefficient. i Specifically:

[0055] G i ={R g C ge C cg C ce ,R tail C tail ,L σ V ge(th) V cesat V ce(on) ,k,R d(on) ,τ rr ,K} (11)

[0056] Optionally, S4 includes:

[0057] IGBT half-bridge circuits experience aging after prolonged operation. This aging primarily occurs between the two IGBT modules. There are N common aging types for IGBT modules. These N aging types are numbered, and an IGBT module aging type set T is constructed using the following formula:

[0058] T={t|1,2,3,…,N} (12)

[0059] Where t is an element in the IGBT module aging type set T, representing the aging type of the IGBT module;

[0060] Define aging deviation constant t represents the aging type of the IGBT module, and t∈T, where j has values ​​from 1 to 14, corresponding to the R of the IGBT. g Cge C cg C ce R tail C tail L σ V ge(th) V cesat V ce(on) , k and R of the freewheeling diode d(on) τ rr K, This is used to indicate the degree to which the value of the model parameter corresponding to number j deviates from the value of the model parameter corresponding to number j under normal conditions when the IGBT module undergoes type t aging and reaches its maximum aging level. When the absolute value is 0, the degree of deviation is 0. The larger the absolute value, the greater the degree of deviation. The value is usually between -1 and 1. The formula is as follows:

[0061]

[0062] Define aging coefficient This represents the coefficient of the model parameter corresponding to IGBT number j when IGBT module number i has undergone a certain degree of aging. The value ranges from 0 to 1. A value of 0 indicates normal, a value closer to 1 indicates more severe aging, and a value of 1 indicates the maximum degree of aging.

[0063] The relationship between the model parameters of the IGBT half-bridge circuit electrical model and the aging type of the IGBT module and the aging degree of the included IGBTs and freewheeling diodes is as follows:

[0064]

[0065] in, k nor , K nor The parasitic capacitance between the gate and emitter, the parasitic capacitance between the collector and gate, the parasitic capacitance between the collector and emitter, the control resistor for the tail current, the control capacitor for the tail current, the parasitic inductance of the collector, the gate-emitter threshold voltage, the saturation voltage drop, the turn-on steady-state forward voltage drop, the equivalent current coefficient flowing through the MOSFET in the structure under normal conditions, the equivalent internal resistance of the freewheeling diode, the time constant of the reverse recovery current, and the value of the reverse recovery current coefficient of the IGBT module under normal conditions.

[0066] Optionally, S5 includes:

[0067] S51: Construct an electrical model of the IGBT half-bridge circuit under aging conditions;

[0068] The electrical model of the IGBT half-bridge circuit under aging conditions is constructed using formulas (1) to (14);

[0069] S52: Monitoring the aging of IGBT half-bridge circuits based on electrical models under aging conditions;

[0070] Data and feature acquisition under normal circumstances: aging coefficient When all values ​​are 0, it means that the aging degree of all aging types is 0, that is, the IGBT under normal conditions, and the electrical model of the IGBT half-bridge circuit under aging conditions is run at this time.

[0071] Data and feature acquisition under aging conditions: by analyzing the aging type t and aging deviation constant of the IGBT module. and aging coefficient By taking different values ​​and setting up IGBT half-bridge circuits under different aging types and degrees, the electrical model of the IGBT half-bridge circuit under the aging condition is run.

[0072] Based on the acquired normal and aging data, the aging status of the IGBT half-bridge circuit is monitored.

[0073] In a second aspect, this application provides an IGBT half-bridge circuit aging monitoring system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described in the first aspect above.

[0074] Beneficial effects:

[0075] The IGBT half-bridge circuit aging monitoring method provided by this invention can realistically simulate the working state of the IGBT half-bridge circuit under normal and aging conditions, providing a basis for aging modeling of more complex circuit systems containing IGBT half-bridge circuits; it can comprehensively simulate the nonlinear transient characteristics of IGBT modules, and can obtain the aging data and characteristics of IGBT modules without physical damage experiments; this method can be extended to aging modeling of other different bridge circuits.

[0076] Furthermore, the model provided by this invention can accurately reflect the transient characteristics of IGBT modules before and after aging, and fully describe the changes in collector-emitter voltage, collector-emitter current, and gate-emitter voltage of IGBT modules, such as delay time, rise and fall rates, steady-state values, peak values, etc. According to different needs, it can simulate different types of aging of IGBT modules, obtain the data and characteristics of IGBT module aging without conducting physical damage experiments, and can perform repeatable experiments. Attached Figure Description

[0077] Figure 1This is a flowchart of an IGBT half-bridge circuit aging monitoring method according to a preferred embodiment of the present invention;

[0078] Figure 2 The diagram shows the equivalent circuit of a preferred embodiment of the present invention, wherein (a) is the equivalent circuit of the IGBT behavior model and (b) is the equivalent circuit of the freewheeling diode.

[0079] Figure 3 This is a preferred embodiment of the IGBT half-bridge circuit of the present invention;

[0080] Figure 4 This is a schematic diagram of the transient waveforms of IGBT turn-on and turn-off in a preferred embodiment of the present invention;

[0081] Figure 5 These are simulation waveforms of the IGBT module under normal and bond wire crack aging conditions according to a preferred embodiment of the present invention.

[0082] Figure 6 The simulation waveforms of the IGBT half-bridge circuit under normal and aging conditions are shown in the preferred embodiment of the present invention. Detailed Implementation

[0083] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0084] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0085] Please see Figure 1 This application provides a method for monitoring the aging of an IGBT half-bridge circuit, comprising:

[0086] S1: Obtain the transient electrical characteristics of the IGBT module when the IGBT half-bridge circuit is turned on and off, and construct a nonlinear transient model of the IGBT module based on the transient electrical characteristics;

[0087] S2: Determine the commutation loop characteristics of the IGBT half-bridge circuit based on the nonlinear transient model of the IGBT module;

[0088] S3: Construct the model parameter set. Based on the characteristics of the IGBT half-bridge circuit commutation loop and the model parameter set, construct the electrical model of the IGBT half-bridge circuit.

[0089] S4: Establish the relationship between the model parameters of the IGBT half-bridge circuit electrical model and the aging type of the IGBT module, the aging degree of the IGBT and the freewheeling diode;

[0090] S5: Construct an electrical model of the IGBT half-bridge circuit under aging conditions based on the electrical model and relational formula of the IGBT half-bridge circuit, and monitor the aging condition of the IGBT half-bridge circuit based on the electrical model under aging conditions.

[0091] The aforementioned IGBT half-bridge circuit aging monitoring method can realistically simulate the working state of IGBT half-bridge circuits under normal and aging conditions, providing a foundation for aging modeling of more complex circuit systems containing IGBT half-bridge circuits; it can comprehensively simulate the nonlinear transient characteristics of IGBT modules, and can obtain aging data and characteristics of IGBT modules without physical damage experiments; this method can be extended to aging modeling of other different bridge circuits.

[0092] Furthermore, the model provided by this invention can accurately reflect the transient characteristics of IGBT modules before and after aging, and fully describe the changes in collector-emitter voltage, collector-emitter current, and gate-emitter voltage of IGBT modules, such as delay time, rise and fall rates, steady-state values, peak values, etc. According to different needs, it can simulate different types of aging of IGBT modules, obtain the data and characteristics of IGBT module aging without conducting physical damage experiments, and can perform repeatable experiments.

[0093] In the complete example, first, please see Figure 2 and Figure 4 The transient electrical characteristics of the IGBT module during IGBT turn-on and turn-off are described respectively, and a nonlinear transient model of the IGBT module is constructed, specifically as follows:

[0094] IGBTs have three operating regions: cutoff, active, and saturation. Freewheeling diodes have two operating states: turn-on and turn-off. Based on these three operating regions and the two operating states of the freewheeling diode, the turn-on and turn-off processes of the IGBT are divided into stages, and the transient electrical characteristics of the IGBT module during turn-on and turn-off are described separately.

[0095] Describe the transient electrical characteristics of the IGBT module when the IGBT is turned on, and construct a nonlinear transient model of the IGBT module when the IGBT is turned on;

[0096] At time t0, the IGBT receives the turn-on command, and the gate drive voltage V... g The output is 15V, the IGBT is operating in the cutoff region, the freewheeling diode is on, and the gate-emitter voltage of the IGBT is v. ge The voltage rises, but remains below the gate-emitter threshold voltage V at which the IGBT turns on. ge(th) The freewheeling diode current i d Decrease, collector-emitter current i c rise;

[0097] At time t1, the gate-emitter voltage v of the IGBT ge The gate-emitter threshold voltage V rises to the IGBT conduction point ge(th) When the IGBT enters the active region, the collector-emitter voltage V ce The gate-emitter voltage v begins to decrease. ge The freewheeling diode current i continues to rise. d The collector-emitter current i continues to decrease. c Continued to rise;

[0098] At time t2, the freewheeling diode current i d The decline reached its negative peak. That is, greater than or equal to When the freewheeling diode enters the off state, the collector-emitter voltage v ce Continuously decreasing; gate-emitter voltage v ge Entering the Miller plateau, the freewheeling diode current i d Reverse recovery from negative peak value, collector-emitter current i c Decrease from the maximum value;

[0099] At time t3, the collector-emitter voltage v of the IGBT ce The pressure drop decreases to the saturation voltage V cesat When the IGBT enters the saturation region, the collector-emitter voltage V... ce The voltage decreases and tends towards a steady-state turn-on; the gate-emitter voltage v ge Rising and trending towards the gate drive voltage V g The freewheeling diode current i d Continuous reverse recovery, collector-emitter current i c It is declining and trending towards an open steady state;

[0100] At time t4, the values ​​of all IGBT variables reach their steady-state values.

[0101] The nonlinear transient model of the IGBT module during IGBT turn-on is constructed as follows:

[0102]

[0103] Where d is the differential of the subsequent variable, R g It is the stray resistance of the IGBT gate; C ge It is the parasitic capacitance between the gate and emitter of the IGBT; C cg It is the parasitic capacitance between the collector and gate of the IGBT; C ce It is the parasitic capacitance between the collector and emitter of the IGBT; R g It is the stray resistance of the IGBT gate; L σ V is the parasitic inductance of the IGBT collector; k is the equivalent current coefficient flowing through the MOSFET within the IGBT structure; ce(on) It is the forward voltage drop of the IGBT in steady state during turn-on; V cesat It is the saturation voltage drop of the IGBT, I L This is the load current of the IGBT half-bridge circuit; V cap δ is the DC-side voltage of the IGBT half-bridge circuit; δ is an intermediate variable in the model, and δ = (C cg ·C ce +C cg ·C ge +C ge ·C ce ); C ies It is the ideal input capacitor for the IGBT, and C ies =C ge +C cg C oes It is the ideal output capacitor for IGBTs, and C oes =C cg +C ce V ce(off) It is the turn-off steady-state voltage of the collector-emitter voltage, and the formula is:

[0104] V ce(off) =V cap +R don ·I L (2)

[0105] In the formula, R don It is the equivalent internal resistance of the freewheeling diode;

[0106] V g It is the IGBT gate drive voltage, and the formula is:

[0107]

[0108] In the formula, V g(on) It is the drive voltage when the IGBT is turned on, V g(off) It is the drive voltage when the IGBT is turned off;

[0109] i d It is the freewheeling diode current, and the formula is:

[0110]

[0111] In the formula, It is the time constant of the reverse recovery phenomenon of the freewheeling diode; current source The reverse recovery phenomenon was simulated, and its value was determined by the first-order reverse recovery current R. rr L rr Circuit control; R rr It is the control resistor for the reverse recovery current; L rr It is the control inductor for the reverse recovery current; K is the reverse recovery current coefficient.

[0112] Formulas (1) to (4) constitute the nonlinear transient model of the IGBT module when the IGBT is turned on.

[0113] Describe the transient electrical characteristics of the IGBT module when the IGBT is turned off, and construct a nonlinear transient model of the IGBT module when the IGBT is turned off;

[0114] At time t5, the IGBT receives a turn-off command, and the gate drive voltage V... g The output is 0V, the IGBT is operating in the saturation region, the freewheeling diode is off, and the gate-emitter voltage of the IGBT is v. ge It decreases, but is still greater than the sustaining load current I. L Minimum value V of the gate-emitter voltage flowing through the IGBT ge(pl) ;

[0115] At time t6, the gate-emitter voltage v of the IGBT ge Drop to sustaining load current I L Minimum value V of the gate-emitter voltage flowing through the IGBT ge(pl) When the IGBT enters the active region, the collector-emitter voltage v ce Rise, gate-emitter voltage v ge Enter the Miller platform;

[0116] At time t7, the collector-emitter voltage v of the IGBT ce Rise to DC side voltage V cap The forward voltage drop V of an ideal diode d(on) The sum of the values ​​of the freewheeling diodes leads to the diodes being switched on, and the collector-emitter voltage V... ce The gate-emitter voltage continues to rise to a peak voltage and then falls, v ge Decrease, collector-emitter current i c decline;

[0117] At time t8, the gate-emitter voltage v of the IGBT geThe gate-emitter threshold voltage V drops to the IGBT conduction point. ge(th) When the IGBT enters the cutoff region, the freewheeling diode is in the on state, and the collector-emitter voltage V... ce The gate-emitter voltage v decreases and tends towards a turn-off steady state. ge Decrease and tend towards the gate drive voltage V g collector-emitter current i c It is decreasing and trending towards a steady-state of shutdown;

[0118] At time t9, the values ​​of all IGBT variables reach their turn-off steady-state values.

[0119] The nonlinear transient model of the IGBT module when the IGBT is turned off is constructed as follows:

[0120]

[0121] Among them, i tail This is the tail current of the IGBT, and its value is determined by the first-order R of the tail current. tail C tail Circuit control, R tail It is the control resistor for the trailing current; C tail It is the control capacitor for the tail current, and the formula is:

[0122]

[0123] V ge(pl) Is maintaining load current I L Gate-emitter voltage v flowing through the IGBT ge The minimum value is given by the formula:

[0124]

[0125] Formulas (5) to (7) constitute the nonlinear transient model of the IGBT module when the IGBT is turned off.

[0126] Construct a nonlinear transient model of the IGBT module;

[0127] Formulas (1) to (7) constitute the nonlinear transient model of the IGBT module.

[0128] Please see Figure 3 Based on the nonlinear transient model of the IGBT module, the characteristics of the commutation loop of the IGBT half-bridge circuit are described.

[0129] The IGBT half-bridge circuit contains two IGBT modules. i / D i The lower part consists of IGBT module T1 / D1 (numbered 1) and the upper part consists of IGBT module T2 / D2 (numbered 2). i Indicates the power device IGBT, D iThis indicates a freewheeling diode, and 'i' represents the IGBT module number. The input of the IGBT half-bridge circuit is the load current I. L and DC side voltage V cap The output is the upper half-bridge current i. x and midpoint voltage u x When the load current flows into the half-bridge circuit, i.e., I... L ≥0, there are three current paths: flowing only through T1, flowing only through D2, and flowing through both T1 and D2 simultaneously, with an output voltage u. x Depends on T1 and V cap Output current i x Depends on T1 and I L When the load current flows out of the half-bridge circuit, i.e., I L <0, there are three current paths: flowing only through T2, flowing only through D1, and flowing through both T2 and D1. The output voltage u x Depends on T2 and V cap Output current i x Depends on T2 and I L The formula is expressed as:

[0130]

[0131] Among them, u x It is the midpoint voltage, i r This is the upper half-bridge current. (~()) represents the inversion operation of the binary number within the parentheses; when the value of the binary number within the parentheses is 1, the output is 0; when the value is 0, the output is 1. S T1 This indicates the switching command for power device T1, used to control the IGBT module numbered 1 in the lower half-bridge. T2 This indicates the switching command for power device T2, used to control the IGBT module numbered 2 in the upper half-bridge. T1 and S T2 The value is either 0 or 1 in binary. When the value is 0, it corresponds to a shutdown instruction, and when the value is 1, it corresponds to a startup instruction. and These represent the collector-emitter current and collector-emitter voltage during the turn-on process and the collector-emitter current and collector-emitter voltage during the turn-off process of power device T1, respectively. and Let T2 represent the collector-emitter current and collector-emitter voltage during the turn-on process and the collector-emitter current and collector-emitter voltage during the turn-off process, respectively. The formulas are as follows:

[0132]

[0133] In the formula, i represents the IGBT module number, with values ​​of 1 and 2; c (t) and v ce (t) represents the collector-emitter current and collector-emitter voltage in the nonlinear transient model of the IGBT module constructed in step 1.

[0134] Construct the model parameter set;

[0135] The parameter set for constructing the electrical model of the IGBT half-bridge circuit is denoted as H, and the elements in the set are the parameter sets G corresponding to the nonlinear transient models of the IGBT modules. i G 1 and G 2 The formula is as follows:

[0136] H = {G} i ,i=1,2} (10)

[0137] Among them, the parameter set G of the nonlinear transient model of the IGBT module i The elements within the IGBT include the gate stray resistance, parasitic capacitance between the gate and emitter, parasitic capacitance between the collector and gate, parasitic capacitance between the collector and emitter, tail current control resistor, tail current control capacitor, collector parasitic inductance, gate-emitter threshold voltage, saturation voltage drop, turn-on steady-state forward voltage drop, equivalent current coefficient flowing through the MOSFET within the structure, and the equivalent internal resistance of the freewheeling diode, the time constant of the reverse recovery current, and the reverse recovery current coefficient. i Specifically:

[0138] G i ={R g C ge C cg C ce ,R tail C tail ,L σ V ge(th) V cesat V ce(on) ,k,R d(on) ,τ rr ,K} (11)

[0139] Construct an electrical model of the IGBT half-bridge circuit;

[0140] Formulas (1) to (11) constitute the electrical model of the IGBT half-bridge circuit. The relationship between the model parameters of the IGBT half-bridge circuit electrical model and the aging type of the IGBT module, and the aging degree of the IGBT and freewheeling diode is established.

[0141] IGBT half-bridge circuits age after prolonged operation, primarily occurring between the two IGBT modules. There are eight common aging types for IGBT modules. These eight aging types are numbered, and an IGBT module aging type set T is constructed using the following formula:

[0142]

[0143] Where t is an element in the IGBT module aging type set T, representing the aging type that occurs in the IGBT module.

[0144] Define aging deviation constant t represents the aging type of the IGBT module, and t∈T, where j has values ​​from 1 to 14, corresponding to the R of the IGBT. g C ge C cg C ce R tail C tail L σ V ge(th) V cesat V ce(on) , k and R of the freewheeling diode d(on) τ rr K, This is used to indicate the degree to which the value of the model parameter corresponding to number j deviates from the value of the model parameter corresponding to number j under normal conditions when the IGBT module undergoes type t aging and reaches its maximum aging level. When the absolute value is 0, the degree of deviation is 0. The larger the absolute value, the greater the degree of deviation. The value is usually between -1 and 1. The formula is as follows:

[0145]

[0146] Define aging coefficient This represents the coefficient of the model parameter corresponding to IGBT number j when IGBT module number i has undergone a certain degree of aging. The value ranges from 0 to 1. A value of 0 indicates normal, a value closer to 1 indicates more severe aging, and a value of 1 indicates the maximum degree of aging.

[0147] The relationship between the model parameters of the IGBT half-bridge circuit electrical model and the aging type of the IGBT module and the aging degree of the included IGBTs and freewheeling diodes is as follows:

[0148]

[0149] Construct an electrical model of the IGBT half-bridge circuit under aging conditions;

[0150] Formulas (1) to (14) constitute the electrical model of the IGBT half-bridge circuit under aging conditions.

[0151] Data and feature acquisition under normal circumstances: aging coefficient When all values ​​are 0, it means that the aging degree of all aging types is 0, that is, the IGBT under normal conditions, and the electrical model of the IGBT half-bridge circuit under aging conditions is run at this time.

[0152] Data and feature acquisition under aging conditions: by analyzing the aging type t and aging deviation constant of the IGBT module. and aging coefficient By taking different values ​​and setting up IGBT half-bridge circuits under different aging types and degrees, the electrical model of the IGBT half-bridge circuit under the aging condition is run.

[0153] Based on the acquired normal and aging data, the aging status of the IGBT half-bridge circuit is monitored.

[0154] In the above embodiments, the IGBTs refer to the data of CM50DU-24F IGBT. An aging simulation experiment of IGBT half-bridge circuit was carried out. The IGBT module was aged by bond wire cracks. The specific parameters of the simulation experiment are shown in Table 1 and Table 2.

[0155] Table 1

[0156]

[0157]

[0158] Table 2

[0159]

[0160] The simulation waveforms of the IGBT module under normal and bond wire crack aging conditions are as follows: Figure 5 As shown, the collector-emitter current i during IGBT turn-on and turn-off processes are described. c collector-emitter voltage v ce and gate-emitter voltage v ge The changes include delay time, rise and fall rates, steady-state value, peak value, etc.; the simulation waveforms of the IGBT half-bridge circuit under normal and aging conditions are as follows: Figure 6 As shown, the IGBT half-bridge circuit is described under load current I... L ≥0 and I L Output voltage u when < 0 x and output current i x It accurately reflects the nonlinear transient characteristics of the IGBT module during turn-on and turn-off, and can obtain the aging data and characteristics of the IGBT module without physical damage experiments.

[0161] This application also provides an IGBT half-bridge circuit aging monitoring system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor performs the steps of the method. This IGBT half-bridge circuit aging monitoring system can implement various embodiments of the above-described IGBT half-bridge circuit aging monitoring method and achieve the same beneficial effects; further details are omitted here.

[0162] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for monitoring the aging of an IGBT half-bridge circuit, characterized in that, include: S1: Obtain the transient electrical characteristics of the IGBT module when the IGBT half-bridge circuit is turned on and off, and construct a nonlinear transient model of the IGBT module based on the transient electrical characteristics; S2: Determine the commutation loop characteristics of the IGBT half-bridge circuit based on the nonlinear transient model of the IGBT module; S3: Construct the model parameter set. Based on the characteristics of the IGBT half-bridge circuit commutation loop and the model parameter set, construct the electrical model of the IGBT half-bridge circuit. S4: Establish the relationship between the model parameters of the IGBT half-bridge circuit electrical model and the aging type of the IGBT module, the aging degree of the IGBT and the freewheeling diode; S5: Construct an electrical model of the IGBT half-bridge circuit under aging conditions based on the IGBT half-bridge circuit electrical model and the aforementioned relationship, and monitor the aging condition of the IGBT half-bridge circuit based on the electrical model under aging conditions. The model parameter set constructed in S3 is as follows: The parameter set for constructing the electrical model of the IGBT half-bridge circuit is denoted as... The elements in the set are the parameter sets corresponding to the nonlinear transient model of the IGBT module. ,Right now and The formula is as follows: Among them, the parameter set of the nonlinear transient model of the IGBT module The elements within the IGBT include the gate stray resistance, parasitic capacitance between the gate and emitter, parasitic capacitance between the collector and gate, parasitic capacitance between the collector and emitter, tail current control resistor, tail current control capacitor, collector parasitic inductance, gate-emitter threshold voltage, saturation voltage drop, turn-on steady-state forward voltage drop, equivalent current coefficient flowing through the MOSFET within the structure, and the equivalent internal resistance of the freewheeling diode, the time constant of the reverse recovery current, and the reverse recovery current coefficient. Specifically:

2. The IGBT half-bridge circuit aging monitoring method according to claim 1, characterized in that, The transient electrical characteristics of the IGBT module when the IGBT half-bridge circuit is turned on are obtained in S1 as follows: set up At that moment, the IGBT receives the turn-on command, and the gate drive voltage... The output is 15V, the IGBT is operating in the cutoff region, the freewheeling diode is on, and the gate-emitter voltage of the IGBT is... The voltage rises, but remains below the gate-emitter threshold voltage at which the IGBT turns on. Freewheeling diode current Decrease, collector-emitter current rise; At time, IGBT gate-emitter voltage The gate-emitter threshold voltage rises to the IGBT turn-on When the IGBT enters the active region, the collector-emitter voltage... The gate-emitter voltage begins to decrease. The freewheeling diode current continues to rise. The collector-emitter current continues to decrease. Continued to rise; At what moment, the freewheeling diode current The decline reached its negative peak. , The reverse recovery current coefficient, The voltage across the control inductor is reduced to the reverse recovery current, causing the freewheeling diode to turn off, and the collector-emitter voltage... Continuing to decrease; gate-emitter voltage Entering the Miller platform, the freewheeling diode current Reverse recovery from negative peak value, collector-emitter current Decrease from the maximum value; At that moment, the collector-emitter voltage of the IGBT Decrease to saturation pressure drop When the IGBT enters the saturation region, the collector-emitter voltage... The gate-emitter voltage decreases and tends towards a steady-state state; Rising and trending towards the gate drive voltage Freewheeling diode current Continuous reverse recovery, collector-emitter current It is declining and trending towards an open steady state; At a certain time, the values ​​of each IGBT variable reach the steady-state value upon turn-on; The transient electrical characteristics of the IGBT module when the IGBT half-bridge circuit is turned off are as follows: At that moment, the IGBT receives a turn-off command, and the gate drive voltage... The output is 0V, the IGBT is operating in the saturation region, the freewheeling diode is off, and the gate-emitter voltage of the IGBT is... The current decreases, but remains greater than the sustaining load current. Minimum value of the gate-emitter voltage flowing through the IGBT ; At time, IGBT gate-emitter voltage Drop to sustaining load current Minimum value of the gate-emitter voltage flowing through the IGBT When the IGBT enters the active region, the collector-emitter voltage... Rise, gate-emitter voltage Enter the Miller platform; At that moment, the collector-emitter voltage of the IGBT Rise to DC side voltage and the forward voltage drop of an ideal diode The sum of the values ​​of the freewheeling diodes leads to the diodes being switched on, and the collector-emitter voltage is [value missing]. The gate-emitter voltage continues to rise to a peak voltage and then decreases. Decrease, collector-emitter current decline; At time, IGBT gate-emitter voltage The gate-emitter threshold voltage drops to the IGBT turn-on state. When the IGBT enters the cutoff region, the freewheeling diode is in the on state, and the collector-emitter voltage... The gate-emitter voltage decreases and tends towards a turn-off steady state. Decrease and tend towards the gate drive voltage collector-emitter current It is decreasing and trending towards a steady-state of shutdown; At that moment, the values ​​of each IGBT variable reach the turn-off steady-state value.

3. The IGBT half-bridge circuit aging monitoring method according to claim 1, characterized in that, In S1, the nonlinear transient model of the IGBT module when the IGBT is turned on satisfies the following relationship: in, It involves differentiating the subsequent variable. It is the stray resistance of the IGBT gate; It is the parasitic capacitance between the gate and emitter of the IGBT; It is the parasitic capacitance between the collector and gate of the IGBT; It is the parasitic capacitance between the collector and emitter of the IGBT; It is the stray resistance of the IGBT gate; It is the parasitic inductance of the IGBT collector; It is the equivalent current coefficient flowing through the MOSFET within the IGBT structure; It is the forward voltage drop of the IGBT in steady state during turn-on; It is the saturation voltage drop of the IGBT. It is the load current of the IGBT half-bridge circuit; It is the DC-side voltage of the IGBT half-bridge circuit; It is an intermediate variable in the model, and ; It is the ideal input capacitor for the IGBT, and ; It is the ideal output capacitor for IGBTs, and ; It is the turn-off steady-state voltage of the collector-emitter voltage, and the formula is: In the formula, It is the equivalent internal resistance of the freewheeling diode; It is the IGBT gate drive voltage, and the formula is: In the formula, It is the drive voltage when the IGBT is turned on. It is the drive voltage when the IGBT is turned off; It is the freewheeling diode current, and the formula is: In the formula, It is the time constant of the reverse recovery phenomenon of the freewheeling diode; current source The reverse recovery phenomenon was simulated, and its value was determined by the first order of the reverse recovery current. Circuit control; It is the control resistor for reverse recovery current; It is the control inductor for reverse recovery current; It is the reverse recovery current coefficient; Among them, formulas (1) to (4) constitute the nonlinear transient model of the IGBT module when the IGBT is turned on; The nonlinear transient model of the IGBT module when the IGBT is turned off satisfies the following relationship: in, This is the tail current of the IGBT, and its value is determined by the first order of the tail current. Circuit control, It is the control resistor for the trailing current; It is the control capacitor for the tail current, and the formula is: It is to maintain the load current Gate-emitter voltage flowing through the IGBT The minimum value is given by the formula: Formulas (5) to (7) constitute the nonlinear transient model of the IGBT module when the IGBT is turned off; formulas (1) to (7) constitute the nonlinear transient model of the IGBT module.

4. The IGBT half-bridge circuit aging monitoring method according to claim 1, characterized in that, S2 includes: The input of the IGBT half-bridge circuit is the load current. and DC side voltage The output is the upper half-bridge current. and midpoint voltage Based on the nonlinear transient model of the IGBT module, the characteristics of the IGBT half-bridge circuit commutator loop are described as follows: in, It is the midpoint voltage. It is the upper half-bridge current. This indicates that the binary number inside the parentheses is inverted. If the value of the binary number inside the parentheses is 1, the output is 0, and if the value is 0, the output is 1. Indicates power devices The switching command is used to control the IGBT module numbered 1 in the lower half-bridge. Indicates power devices The switching command is used to control the IGBT module numbered 2 in the upper half-bridge. and The value is either 0 or 1 in binary. When the value is 0, it corresponds to a shutdown instruction, and when the value is 1, it corresponds to a startup instruction. , and , Representing power devices Collector-emitter current and collector-emitter voltage during the turn-on process and during the turn-off process. , and , Representing power devices The formulas for collector-emitter current and collector-emitter voltage during the turn-on process and during the turn-off process are as follows: In the formula, This indicates the IGBT module number, with values ​​of 1 and 2. and These are the collector-emitter current and collector-emitter voltage in the nonlinear transient model of the IGBT module constructed in step 1.

5. The IGBT half-bridge circuit aging monitoring method according to claim 1, characterized in that, S4 includes: IGBT half-bridge circuits age after prolonged operation, primarily affecting the two IGBT modules. Common types of IGBT module aging include... Seed, for The aging types are numbered to construct an IGBT module aging type set. The formula is as follows: in, It is a set of IGBT module aging types. The elements within indicate the aging type of the IGBT module; Define aging deviation constant , Indicates the type of aging that has occurred in the IGBT module, and , The values ​​range from 1 to 14, corresponding to the IGBT values ​​respectively. , , , , , , , , , , and freewheeling diode , , , Used to indicate that the IGBT module has generated When the type is aging and reaches its maximum aging level, it is numbered. The corresponding model parameter values ​​deviate from the normal numbering of the IGBT module. The degree of the corresponding model parameter values, When the absolute value is 0, the degree of deviation is 0; the larger the absolute value, the greater the degree of deviation. A typical value is [value missing]. The formula is as follows: Define aging coefficient , indicating that the number is When the IGBT module reaches a certain degree of aging, the serial number is... The coefficients of the corresponding model parameters, Value A value of 0 indicates normal, a value closer to 1 indicates more severe aging, and a value of 1 indicates the maximum degree of aging. The relationship between the model parameters of the IGBT half-bridge circuit electrical model and the aging type of the IGBT module and the aging degree of the included IGBTs and freewheeling diodes is as follows: in, , , , , , , , , , , , , , The parasitic capacitance between the gate and emitter, the parasitic capacitance between the collector and gate, the parasitic capacitance between the collector and emitter, the control resistor for the tail current, the control capacitor for the tail current, the parasitic inductance of the collector, the gate-emitter threshold voltage, the saturation voltage drop, the turn-on steady-state forward voltage drop, the equivalent current coefficient flowing through the MOSFET in the structure under normal conditions, the equivalent internal resistance of the freewheeling diode, the time constant of the reverse recovery current, and the value of the reverse recovery current coefficient of the IGBT module under normal conditions.

6. The IGBT half-bridge circuit aging monitoring method according to claim 1, characterized in that, S5 includes: S51: Construct an electrical model of the IGBT half-bridge circuit under aging conditions; The electrical model of the IGBT half-bridge circuit under aging conditions is constructed using formulas (1) to (14); S52: Monitoring the aging of IGBT half-bridge circuits based on electrical models under aging conditions; Data and feature acquisition under normal circumstances: aging coefficient When all values ​​are 0, it means that the aging degree of all aging types is 0, that is, the IGBT under normal conditions, and the electrical model of the IGBT half-bridge circuit under aging conditions is run at this time. Data and feature acquisition under aging conditions: By analyzing the aging types occurring in the IGBT modules aging deviation constant and aging coefficient By taking different values ​​and setting up IGBT half-bridge circuits under different aging types and degrees, the electrical model of the IGBT half-bridge circuit under the aging condition is run. Based on the acquired normal and aging data, the aging status of the IGBT half-bridge circuit is monitored.

7. An IGBT half-bridge circuit aging monitoring system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method described in any one of claims 1 to 6.

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