Crimping IGBT device electric heating joint simulation method based on grid resistor

Abstract

The invention relates to a crimped IGBT device electric heating joint simulation method based on a grid resistor, and belongs to the field of power semiconductor devices. According to the simulation method, a circuit model and a thermal field model are established, and a Matlab algorithm is utilized to regulate and control grid resistance and temperature, so that bidirectional coupling between the circuit model and the thermal field model is realized. Wherein the circuit model adopts SIMULINK simulation, and provides circuit data for electric heating joint simulation modeling; the thermal field model adopts COSMOL simulation and provides thermal field data of electric heating joint simulation modeling. The corrected power loss is output as an electric-heat joint simulation result, and it is verified that the simulation method has high accuracy and stability. The simulation method can be used for evaluating the temperature change and the power loss of the crimping IGBT device under different working conditions, and reference is provided for device design optimization.

Description

Technical Field

[0001] The invention belongs to the field of power semiconductor devices and relates to an electric-thermal joint simulation method of a crimped IGBT device based on a gate resistor. Background Art

[0002] IGBT devices are the most popular power switching devices at present. They have been widely used in the process of power conversion because of their many advantages such as high current density and low saturation voltage drop. IGBT devices usually operate under extreme working conditions, such as high voltage, high current, and high switching frequency. The above factors all cause the devices to generate high power consumption and high junction temperature. There is a strong coupling relationship between the electrical characteristics of IGBT devices and the junction temperature, that is, the temperature of the device will rise rapidly in a short time, which will affect the semiconductor characteristics of the IGBT chip and the material characteristics of the packaging structure, and finally intuitively manifested as changes in the electrical characteristics of the module port, and the power consumption generated will affect the junction temperature. Therefore, when using IGBT devices for simulation, it is of great significance to consider the electrical characteristics and temperature distribution characteristics of the device.

[0003] In order to obtain the device's joint electrothermal modeling, some scholars have constructed an IGBT electrothermal model based on electric field-thermal field coupling using the finite element method, in which the electrical characteristics of the IGBT are characterized by a simplified behavioral model. Due to the lack of an accurate electrical model, it is impossible to fully and accurately simulate the electrothermal characteristics of the IGBT. Some scholars use the thermal simulation software Icepak to provide a thermal impedance network for the circuit-level simulation software Simplorer to achieve joint simulation of the circuit and thermal field, but this process is one-way and cannot achieve bidirectional coupling between electricity and heat.

[0004] The components of the crimped IGBT device are directly electrically bonded by mechanical pressure, in which the IGBT gate is connected to the driver board through a spring pin to form a gate drive signal path. Due to the existence of the electrothermal coupling effect and the mismatch of the thermal expansion coefficients of the various layers of the crimped IGBT device, the thermal stability of the crimped IGBT device is greatly affected. As time goes by and the temperature changes, the various layers of material undergo expansion and contraction, causing the spring pins to undergo fluctuating thermal stresses, gradually aging and relaxing. This relaxation leads to an increase in the contact resistance between the gate spring pin and the gate pad of the chip and a prolonged device turn-on time, which increases power loss, thereby increasing the local temperature of the gate and accelerating device failure. Therefore, the electrothermal coupling relationship of the crimped IGBT device can be established by simulating the change law of the gate resistance.

[0005] Based on the above background, the present invention aims at simulating the electrical characteristics and temperature characteristics of a crimped IGBT device and proposes an electrical and thermal co-simulation method for a crimped IGBT device based on gate resistance. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a gate resistor-based pressure-bonded IGBT device electrothermal joint simulation method to achieve pressure-bonded IGBT device power loss simulation

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A gate resistor-based electrothermal co-simulation method for a crimped IGBT device, the method comprising the following steps:

[0009] S1: Establish a circuit model and a thermal field model, wherein the circuit model is simulated by SIMULINK and provides circuit data for electric-thermal joint simulation modeling, and the thermal field model is simulated by COSMOL and provides thermal field data for electric-thermal joint simulation modeling;

[0010] S2: The gate resistance and temperature are regulated by Matlab algorithm to realize data transmission between the circuit model and the thermal field model;

[0011] S3: Based on the power loss calculated by the circuit model, the dynamic heat transfer characteristics are solved through the thermal field model, and the gate resistance is fed back to the circuit model;

[0012] S3: The power loss formula of the crimped insulated gate bipolar transistor (IGBT) device chip is as follows:

[0013] P=P con_T +P on_T +P off_T

[0014] Where P con_T Represents the conduction loss, P on_T Indicates the turn-on loss, P off_T represents the turn-off loss;

[0015] For an IGBT chip, its average conduction loss in one switching cycle is expressed as:

[0016]

[0017] Where t represents time in seconds, t sw represents the switching cycle, V ce (t) represents the collector-emitter saturation voltage drop, I c (t) represents the load current related to time t; during the on-time of each switching cycle, V ce (t) and I c (t) is constant, and the following formula is obtained:

[0018]

[0019] In the formula, t1 and t2 represent the turn-on and turn-off time of the chip in a switching cycle, respectively, δ = (t2-t1) / t sw Represents duty cycle; I c is the load current, which is a constant;

[0020] The average switching loss of IGBT chip is expressed as:

[0021]

[0022] The above formula can be rewritten as follows:

[0023]

[0024] In the formula, f sw =1 / t sw Indicates the switching frequency, E sw (I c ) represents the switching energy loss, represents the DC voltage coefficient, represents the gate resistance coefficient, represents the temperature coefficient; where, and Respectively expressed as:

[0025]

[0026]

[0027] The IGBT chip switching loss formula is rewritten as follows:

[0028]

[0029] Where V dc Indicates DC voltage, V dc_ref Represents the reference voltage, R g_ref Represents the reference resistance, T j_ref represents the reference junction temperature, and All are empirical parameters, N g_ref is the gate resistance correction parameter, A sw_T and B sw_T All are unknown coefficients; the gate resistance R of the crimped IGBT device g It is highly linearly correlated with the power loss P output by the electric-thermal combined model;

[0030] S4: The corrected power loss is output as the result of the electric-thermal joint simulation; the circuit model provides loss parameters for the thermal field model, and the influence of temperature T on the loss calculation is realized through relevant temperature-sensitive parameters, including the intrinsic carrier concentration n i , bandgap width Eg , carrier mobility μ and carrier lifetime τ, threshold voltage V th (T), emitter saturation current I c (T), expressed by the IGBT physical model affected by temperature changes:

[0031]

[0032] V th (T) = V th (T0)-a(T-)T0

[0033]

[0034] In the formula: T0 is 300K; μ0 is the electron and hole mobility at temperature T0; τ0 is the carrier lifetime of the base region and the buffer layer at temperature T0; γ is an empirical constant, for IGBT chips, γ = 2.5; λ is the carrier lifetime fitting coefficient; a is the threshold voltage correction coefficient at temperature T0; b is the emitter saturation current correction coefficient at temperature T0.

[0035] Further, the circuit model includes:

[0036] Temperature feedback interface T j , Gate resistance feedback interface R g and loss output interface P;

[0037] Among them, the temperature feedback interface is used to feed back the temperature calculated by the thermal field model to the circuit model;

[0038] The gate resistance feedback interface is used to feed back the gate resistance calculated by the circuit model to the thermal field model;

[0039] The loss output interface is used to output the power loss of the circuit model.

[0040] Furthermore, the thermal field model considers the three-dimensional unsteady-state heat conduction differential equation of the internal heat source:

[0041]

[0042] Where ρ is the material density; c p is the specific heat capacity; is the direction vector in the Cartesian coordinate system; T is the thermodynamic temperature; λ(T) is the thermal conductivity of the material; Q v is the heat generated by the internal heat source per unit volume per unit time, provided by the circuit model;

[0043] The gate resistance is fed back to the circuit model through the feedback interface, affecting the power loss calculation of the circuit model;

[0044] When performing thermal field simulation, the IGBT chip is set as a heat source, and the circuit simulation is called in real time through the Matlab script file to obtain the P loss parameter, and it is added to the heat source area of ​​the thermal field model in the form of a volumetric heat source, and the gate resistor R g Feedback to the circuit model.

[0045] The beneficial effects of the present invention are:

[0046] (1) By using the gate resistance as the transfer parameter, a bidirectional coupling between the circuit model and the thermal field model is achieved, which more accurately simulates the electrothermal characteristics of the crimped IGBT device and thus improves the accuracy of the power loss calculation.

[0047] (2) This simulation method can dynamically simulate the temperature changes and power losses of press-fit IGBT devices under different working conditions, which helps to evaluate the reliability and life of the device.

[0048] (3) By simulating the variation of gate resistance, the electrothermal coupling relationship of the crimped IGBT device can be established, and the effect of gate resistance on device performance can be further analyzed.

[0049] (4) This simulation method can provide a reference for the design optimization of press-fit IGBT devices, such as optimizing the gate resistance value and improving the packaging structure, so as to improve the reliability and performance of the device.

[0050] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0052] Figure 1 The principle of electric and thermal co-simulation of crimped IGBT devices based on gate resistance;

[0053] Figure 2 Schematic diagram of the circuit model of the crimped IGBT device considering the gate resistance;

[0054] Figure 3 Thermal field model of press-fit IGBT device and its mesh generation results;

[0055] Figure 4 is the power cycle simulation result;

[0056] Figure 5 is the power loss simulation result;

[0057] Figure 6 This is the junction temperature-time curve. DETAILED DESCRIPTION

[0058] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and the features in the embodiments can be combined with each other without conflict.

[0059] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0060] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0061] The present invention is a gate resistor-based electrothermal co-simulation method for crimping IGBT devices. The method comprises the following steps:

[0062] S1: The principle of electro-thermal joint simulation of crimped IGBT devices based on gate resistance is proposed. Figure 1 As shown. The heat source is used as the initial condition for circuit simulation and thermal field simulation, and provides the initial value of power loss. In the simulation modeling stage, SIMULINK is used for circuit modeling and circuit data for electric-thermal joint simulation modeling is provided; COSMOL is used for finite element modeling and thermal field data for electric-thermal joint simulation modeling is provided. The circuit model and the thermal field model use Matlab algorithm to control the gate resistance and temperature, and realize the data transmission between the electric-thermal joint model. The corrected power loss is output as the result of the electric-thermal joint simulation.

[0063] S2: The feasibility of the gate resistance in S1 as a transfer parameter of the electrothermal joint model is verified, and it is analyzed that there is a high degree of linear fit between the gate resistance and the electrothermal joint simulation results.

[0064] S3: The power loss formula of crimped IGBT device chip is as follows:

[0065] P=P con_T +P on_T +P off_T

[0066] Where P con_T Represents the conduction loss, P on_T Indicates the turn-on loss, P off_T represents the turn-off loss.

[0067] For an IGBT chip, its average conduction loss in one switching cycle can be expressed as:

[0068]

[0069] where t sw represents the switching cycle, V ce (t) represents the collector-emitter saturation voltage drop, I c (t) represents the load current. Considering that the switching frequency of the IGBT module in the inverter circuit is high and the on-time of each switching cycle is short, it can be assumed that during the on-time of each switching cycle, V ce (t) and I c (t) is constant, the following formula can be obtained:

[0070]

[0071] Where, δ = (t2-t1) / t sw Indicates the duty cycle.

[0072] The average switching loss of IGBT chip can be expressed as:

[0073]

[0074] Since the switching frequency of the IGBT module is high and its voltage and current change process is complex, the switching loss is usually not calculated by multiplying the voltage by the current, but based on the switching energy loss measurement data under specific experimental conditions. At the same time, the switching loss is calculated by considering the influence of factors such as load current, DC voltage, gate resistance and chip junction temperature. Therefore, the above formula can be rewritten as follows:

[0075]

[0076] In the formula, f sw =1 / tsw Indicates the switching frequency, E sw (I c ) represents the switching energy loss, represents the DC voltage coefficient, represents the gate resistance coefficient, represents the temperature coefficient. and K Tj_T Respectively expressed as:

[0077]

[0078] Therefore, the IGBT chip switching loss formula can be rewritten as follows:

[0079]

[0080] Where V dc Indicates DC voltage, V dc_ref Represents the reference voltage, R g_ref Represents the reference resistance, T j_ref represents the reference junction temperature, and All are empirical parameters, N g_ref is the gate resistance correction parameter, A sw_T and B sw_T All of them are unknown coefficients. From the above formula, it can be seen that the gate resistance R of the crimped IGBT device g It is highly linearly correlated with the power loss P output by the electrothermal joint model. Therefore, the electrothermal joint model of the press-fit IGBT device based on gate resistance has high accuracy and stability.

[0081] S4: Verify the electric-thermal joint simulation method proposed in S1, and establish a circuit model and a thermal field model respectively. The circuit model provides loss parameters for the thermal field model. The influence of temperature on loss calculation is mainly realized through related temperature-sensitive parameters, including intrinsic carrier concentration, bandgap width, carrier mobility and lifetime, threshold voltage, and emitter saturation current. The above relationship can be expressed by the IGBT physical model affected by temperature changes:

[0082]

[0083] V th (T) = V th (T0)-a(T-)T0

[0084]

[0085] In the formula: T0 is generally 300K; μ0 is the electron and hole mobility at temperature T0; τ0 is the carrier lifetime of the base region and buffer layer at temperature T0; γ and λ are fitting coefficients respectively; temperature coefficients a and b are positive. Further build an external circuit in Simulink to construct a circuit model for working condition analysis, as shown in the schematic diagram Figure 2 In order to facilitate the data transmission control of the electric and thermal joint simulation, the temperature feedback interface T j , Gate resistance feedback interface R g and loss output interface P.

[0086] S5: According to the principle of electric-thermal joint simulation, after completing the loss calculation of the IGBT circuit model, it is necessary to further solve its dynamic heat transfer characteristics through the thermal field model based on finite element simulation. Applying the law of conservation of energy and Fourier's law, the three-dimensional unsteady-state heat conduction differential equation considering the internal heat source is:

[0087]

[0088] Where ρ is the material density; c p is the specific heat capacity; is the direction vector in the Cartesian coordinate system; T is the thermodynamic temperature; λ(T) is the thermal conductivity of the material; Q v It is the heat generated by the internal heat source in unit volume per unit time. This parameter is provided by the circuit model.

[0089] Figure 3 This is the thermal field model of the press-fit IGBT device and its mesh generation results.

[0090] When performing thermal field simulation, the IGBT chip is set as a heat source, and the circuit simulation is called in real time through the Matlab script file to obtain the P loss parameter, and it is added to the heat source area of ​​the thermal field model in the form of a volumetric heat source, and the gate resistor R g Feedback to the circuit model.

[0091] In order to verify the accuracy of the electro-thermal co-simulation model of the crimped IGBT device, power cycle simulation was applied to the electro-thermal co-simulation model and compared with the power cycle test. The simulation and test conditions were the same, with a conduction current of 125A, a conduction time of 25s within one cycle, and a turn-off time of 15s. The output of the model at the maximum temperature is as follows: Figure 4 The power loss simulation results of the model are shown in Figure 5 The junction temperature-time curves of the model and test output are shown in Figure 6 shown.

[0092] The results show that an increase in gate resistance will affect the increase in device losses, and the error between the output of the electrothermal joint simulation model and the experimental results is within 1%.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. An electrothermal joint simulation method for a crimped IGBT device based on gate resistance, characterized in that: The method comprises the following steps: S1: Establish a circuit model and a thermal field model, wherein the circuit model is simulated by SIMULINK and provides circuit data for electric-thermal joint simulation modeling, and the thermal field model is simulated by COSMOL and provides thermal field data for electric-thermal joint simulation modeling; S2: The gate resistance and temperature are regulated by Matlab algorithm to realize data transmission between the circuit model and the thermal field model; S3: Based on the power loss calculated by the circuit model, the dynamic heat transfer characteristics are solved through the thermal field model, and the gate resistance is fed back to the circuit model; S3: The power loss formula of the crimped insulated gate bipolar transistor (IGBT) device chip is as follows: P=P con_T +P on_T +P off_T Where P con_T Represents the conduction loss, P on_T Indicates the turn-on loss, P off_T represents the turn-off loss; For an IGBT chip, its average conduction loss in one switching cycle is expressed as: Where t represents time in seconds, t sw represents the switching cycle, V ce (t) represents the collector-emitter saturation voltage drop, I c (t) represents the load current related to time t; during the on-time of each switching cycle, V ce (t) and I c (t) is constant, and the following formula is obtained: In the formula, t1 and t2 represent the turn-on and turn-off time of the chip in a switching cycle, respectively, δ = (t2-t1) / t sw Represents duty cycle; I c is the load current, which is a constant; The average switching loss of IGBT chip is expressed as: The above formula can be rewritten as follows: In the formula, f sw =1 / t sw Indicates the switching frequency, E sw (I c ) represents the switching energy loss, represents the DC voltage coefficient, represents the gate resistance coefficient, represents the temperature coefficient; where and Respectively expressed as: The IGBT chip switching loss formula is rewritten as follows: Where V dc Indicates DC voltage, V dc_ref Represents the reference voltage, R g_ref Represents the reference resistance, T j_ref represents the reference junction temperature, and All are empirical parameters, N g_ref is the gate resistance correction parameter, A sw_T and B sw_T All are unknown coefficients; the gate resistance R of the crimped IGBT device g It is highly linearly correlated with the power loss P output by the electric-thermal combined model; S4: The corrected power loss is output as the result of the electric-thermal joint simulation; the circuit model provides loss parameters for the thermal field model, and the influence of temperature T on the loss calculation is realized through relevant temperature-sensitive parameters, including the intrinsic carrier concentration n i , bandgap width E g , carrier mobility μ and carrier lifetime τ, threshold voltage V th (T), emitter saturation current I c (T), expressed by the IGBT physical model affected by temperature changes: V th (T)=V th (T0)-a(T-)T0 In the formula: T0 is 300K; μ0 is the electron and hole mobility at temperature T0; τ0 is the carrier lifetime of the base region and the buffer layer at temperature T0; γ is an empirical constant, for IGBT chips, γ = 2.5; λ is the carrier lifetime fitting coefficient; a is the threshold voltage correction coefficient at temperature T0; b is the emitter saturation current correction coefficient at temperature T0.

2. The gate resistor-based electrothermal co-simulation method for crimping IGBT devices according to claim 1, characterized in that: The circuit model includes: Temperature feedback interface T j , Gate resistance feedback interface R g and loss output interface P; Among them, the temperature feedback interface is used to feed back the temperature calculated by the thermal field model to the circuit model; The gate resistance feedback interface is used to feed back the gate resistance calculated by the circuit model to the thermal field model; The loss output interface is used to output the power loss of the circuit model.

3. The gate resistor-based electrothermal co-simulation method for crimping IGBT devices according to claim 1, characterized in that: The thermal field model considers the three-dimensional unsteady heat conduction differential equation of the internal heat source: Where ρ is the material density; c p is the specific heat capacity; is the direction vector in the Cartesian coordinate system; T is the thermodynamic temperature; λ(T) is the thermal conductivity of the material; Q v is the heat generated by the internal heat source per unit volume per unit time, provided by the circuit model; The gate resistance is fed back to the circuit model through the feedback interface, affecting the power loss calculation of the circuit model; When performing thermal field simulation, the IGBT chip is set as a heat source, and the circuit simulation is called in real time through the Matlab script file to obtain the P loss parameter, and it is added to the heat source area of ​​the thermal field model in the form of a volumetric heat source, and the gate resistor R g Feedback to the circuit model.

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