IGBT loop stray inductance identification method and system

Abstract

The invention belongs to the field of equivalent stray inductance identification, and particularly relates to an IGBT loop stray inductance identification method and system. The method comprises the following steps of: updating a stray inductance estimated value and a state variable of the sliding mode observer every set time step in a set time period; the state variable is the estimated value of the IGBT loop current and is updated according to the sliding mode observer; the sliding film observer comprises a function for determining a change rate of a state variable according to a stray inductance estimated value, busbar capacitor voltage in an IGBT loop and equivalent voltage of an IGBT and a load, and a function for determining a change rate of the stray inductance estimated value according to positive and negative of a sliding surface; the sliding surface is determined according to the difference between an IGBT loop current actual value and a state variable; the stray inductance estimation value is updated according to the stray inductance estimation value at the last set time step and the product of the change rate of the stray inductance estimation value and the set time step value; and when the stray inductance estimation value is updated for the first time, the set initial value is taken as the stray inductance estimation value at the last set time step.

Description

Technical Field

[0001] The invention belongs to the field of equivalent stray inductance identification, and specifically relates to an IGBT loop stray inductance identification method and system. Background Art

[0002] In power electronics and motor drive systems, busbar stray inductance is a key parameter that directly affects the system's dynamic performance, efficiency, and stability; therefore, accurately identifying and monitoring its changes is essential for optimizing system control strategies, preventing potential failures, and improving overall system performance.

[0003] Traditional stray inductance identification methods mainly include experimental measurement method, model parameter identification method and online identification method based on signal processing. However, these methods all have corresponding limitations; among them, the experimental measurement method usually requires offline measurement under specific conditions, which cannot reflect the changes of stray inductance in real time during operation, and is subject to the accuracy and stability of the measurement equipment. The accuracy of the model parameter identification method depends on accurate system models and sufficient input and output data. In practical applications, due to the existence of nonlinearity, uncertainty and external interference in different scenarios, the establishment of the model and the identification of parameters in the model parameter identification method are often difficult and error-prone, resulting in poor adaptability. Online identification methods based on signal processing, such as frequency domain analysis and Kalman filtering, can achieve real-time identification, but may be affected by factors such as noise, sampling frequency and computational complexity, resulting in insufficient identification accuracy and robustness. Summary of the invention

[0004] The object of the present invention is to provide an IGBT circuit stray inductance identification method and system, which are used to solve the problem that the stray inductance identification method in the prior art is difficult to achieve accurate and adaptable online stray inductance identification.

[0005] In order to achieve the above object, the present invention provides an IGBT circuit stray inductance identification method, which updates the stray inductance estimation value and the state variable of the sliding film observer at every set time step within a set time period;

[0006] The state variable is an estimated value of the IGBT loop current, which is updated according to the sliding film observer; the sliding film observer includes a function for determining the rate of change of the state variable according to the estimated value of stray inductance, the busbar capacitor voltage in the IGBT loop, and the equivalent voltage of the IGBT and the load, and a function for determining the rate of change of the estimated value of stray inductance according to the positive or negative of the sliding surface; the sliding surface is determined according to the difference between the actual value of the IGBT loop current and the state variable;

[0007] The stray inductance estimation value is updated based on the stray inductance estimation value at the last set time step and the product of the rate of change of the stray inductance estimation value at the last set time step and the set time step value; when the stray inductance estimation value is updated for the first time within the set time period, the set initial value is taken as the stray inductance estimation value at the last set time step.

[0008] Furthermore, the set time period is a time period in which the current change rate of the IGBT device in the IGBT loop is the largest during the on and off process.

[0009] Further, the function that determines the rate of change of the estimated value of stray inductance according to the positive or negative of the sliding surface is determined by the product of a sign function corresponding to the difference between the actual value of the IGBT loop current and the state variable and a set positive adjustment coefficient; or, the function that determines the rate of change of the estimated value of stray inductance according to the positive or negative of the sliding surface is determined by the product of a sign function corresponding to the positive or negative difference between the state variable and the actual value of the IGBT loop current and a set negative adjustment coefficient.

[0010] Furthermore, the function for determining the rate of change of the state variable according to the busbar capacitor voltage in the IGBT circuit and the estimated values ​​of the IGBT, load and stray inductance is obtained by the Kirchhoff voltage equation determined according to the busbar capacitor voltage in the IGBT circuit and the equivalent voltages of the IGBT, load and stray inductance, and the relationship between the equivalent voltage of the stray inductance and the rate of change of the state variable determined according to the estimated value of the stray inductance.

[0011] Further, the method of updating the stray inductance estimation value according to the stray inductance estimation value at the last set time step and the product of the rate of change of the stray inductance estimation value at the last set time step and the set time step value includes:

[0012]

[0013] in, It is the estimated value of stray inductance at the current set time step; is the estimated value of stray inductance at the last set time step; is the rate of change of the estimated value of stray inductance at the last set time step; Δt is the value of the set time step.

[0014] Furthermore, the function of the rate of change of the state variable determined according to the estimated value of stray inductance, the busbar capacitance voltage in the IGBT circuit, and the equivalent voltage of the IGBT and the load is:

[0015]

[0016] in, is the rate of change of the state variable; U dc(t) is the busbar capacitor voltage in the IGBT circuit; U ce (t) is the equivalent voltage of the IGBT in the IGBT circuit; U d (t) is the equivalent voltage of the load in the GBT circuit; is the estimated value of stray inductance.

[0017] The above technical solution of the present invention provides a new method for identifying stray inductance of an IGBT circuit, and its beneficial effects include: by taking the estimated value of the IGBT circuit current as the state variable of the sliding mode observer, and combining the estimated value of the stray inductance, and other voltages in the IGBT circuit except the stray inductance equivalent voltage (such as the busbar capacitor voltage, the equivalent voltage of the IGBT and the load), the rate of change of the state variable is determined. This method uses voltage parameters that are easy to obtain in real time to construct the relationship between the estimated value of the stray inductance and the rate of change of the state variable, thereby linking the state variable of the sliding mode observer with the estimated value of the stray inductance. On this basis, the difference between the actual value of the IGBT circuit current and the state variable (i.e., the estimated value of the IGBT circuit current) is used as the sliding surface of the sliding mode observer, and the estimated value of the stray inductance is updated by the numerical integration of the Euler method according to the rate of change of the estimated value of the stray inductance calculated by the sliding surface. In this way, the nonlinear processing capability of the sliding mode observer can be utilized, and the increase or decrease of the estimated value of the stray inductance can be adaptively adjusted by judging the deviation between the estimated value and the actual value of the IGBT circuit current. Repeating this adjustment process multiple times within a set time period can make the estimated value of the IGBT loop current close to its actual value, and at the same time make the estimated value of the stray inductance close to its actual value, thereby ensuring the accuracy of stray inductance identification. This method makes full use of the nonlinear processing capability of the sliding mode observer and only involves a few voltage parameters that are easy to obtain in real time. Therefore, even in complex, nonlinear and uncertain power electronics and motor drive systems, a relatively accurate stray inductance estimate can be obtained. This method has strong adaptability, does not require complex calculation or modeling processes, is less affected by external factors, and has better robustness.

[0018] The present invention also provides an IGBT loop stray inductance identification system, comprising a processor, wherein the processor is used to execute a computer program to implement the steps of the above-mentioned IGBT loop stray inductance identification method.

[0019] The above technical solution of the present invention provides a new IGBT circuit stray inductance identification system, which can achieve the same beneficial effects as the above IGBT circuit stray inductance identification method. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A flowchart of a method for detecting an expanded carbon layer of a flame retardant implemented by a flame retardant testing device in an embodiment of a method for identifying stray inductance of an IGBT circuit of the present invention;

[0021] Figure 2 It is a structural schematic diagram of a flame retardant testing device in an embodiment of the IGBT circuit stray inductance identification method of the present invention;

[0022] Figure 3 It is a curve diagram of the change of the resistance value during the combustion process of the flame retardant SBS sample with an IFR flame retardant content of 40% in the embodiment of the IGBT circuit stray inductance identification method of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0024] Embodiment of IGBT loop stray inductance identification method

[0025] This embodiment provides a technical solution for an IGBT circuit stray inductance identification method. By combining the nonlinear processing capability of a sliding mode observer and the numerical integration principle of the Euler algorithm, the method can more accurately identify the value of stray inductance in a complex, nonlinear and uncertain power electronics and motor drive system environment, thereby improving the robustness and accuracy of stray inductance identification.

[0026] Reference Figure 1 , the IGBT circuit stray inductance identification method specifically includes:

[0027] Within a set time period, the stray inductance estimation value and the state variables of the sliding film observer are updated at every set time step;

[0028] The state variable is an estimated value of the IGBT loop current, which is updated according to the sliding film observer; the sliding film observer includes a function for determining the rate of change of the state variable according to the estimated value of stray inductance, the busbar capacitor voltage in the IGBT loop, and the equivalent voltage of the IGBT and the load, and a function for determining the rate of change of the estimated value of stray inductance according to the positive or negative of the sliding surface; the sliding surface is determined according to the difference between the actual value of the IGBT loop current and the state variable;

[0029] The stray inductance estimation value is updated based on the stray inductance estimation value at the last set time step and the product of the rate of change of the stray inductance estimation value at the last set time step and the set time step value; when the stray inductance estimation value is updated for the first time within the set time period, the set initial value is taken as the stray inductance estimation value at the last set time step.

[0030] Therefore, this method uses the estimated value of the IGBT loop current as the state variable updated according to the sliding film observer, and determines the rate of change of the state variable through the estimated value of the stray inductance and other voltages in the IGBT loop except the equivalent voltage of the stray inductance (busbar capacitor voltage and equivalent voltages of the IGBT and load). This is equivalent to constructing the relationship between the rate of change of the estimated value of the stray inductance and the state variable through voltage parameters that can be easily obtained in real time, thereby linking the state variable of the sliding mode observer with the estimated value of the stray inductance; on this basis, the difference between the actual value of the IGBT loop current and the state variable (the estimated value of the IGBT loop current) is used as the sliding surface of the sliding film observer, and the rate of change of the estimated value of the stray inductance calculated according to the sliding surface is used to update the estimated value of the stray inductance through the numerical integration principle of the Euler algorithm, which can be used The nonlinear processing capability of the sliding mode observer can adaptively adjust the increase or decrease of the estimated value of the stray inductance by judging whether the estimated value of the IGBT loop current is larger or smaller than the actual value, and repeat the adjustment process multiple times within a set time period, so as to ensure that the estimated value of the IGBT loop current is close to the actual value of the IGBT loop current while making the estimated value of the stray inductance close to the actual value of the stray inductance, thereby ensuring the accuracy of the stray inductance identification result; this method utilizes the nonlinear processing capability of the sliding mode observer and only involves a few voltage parameters that are easier to obtain in real time, thus ensuring that a relatively accurate stray inductance estimation value can be obtained in a complex, nonlinear and uncertain power electronics and motor drive system environment, with stronger adaptability, no need for complex calculation or modeling process, less affected by external factors, and better robustness.

[0031] The set time period is the time period when the current change rate of the IGBT device in the IGBT circuit is the largest during the on-off process; during this time period, the current change is more obvious and more linear and smoother than other time periods, which is the most appropriate time to associate the change rate of the current estimate value with the stray inductance estimate value for stray inductance identification. The time period when the current change rate of the IGBT device is the largest during the on-off process can be obtained by selecting a time period when the current change rate of the IGBT circuit reaches or approaches a set upper limit threshold, or by selecting a time period when the current change rate of the IGBT circuit differs from a preset maximum current change rate by less than a set difference threshold.

[0032] In this embodiment, on the basis of the state variable being the estimated value of the IGBT loop current, a function for determining the rate of change of the state variable according to the busbar capacitor voltage in the IGBT loop and the estimated values ​​of the IGBT, load and stray inductance is obtained by using the Kirchhoff voltage equation determined according to the busbar capacitor voltage in the IGBT loop and the equivalent voltages of the IGBT, load and stray inductance and the equivalent voltage of the stray inductance determined according to the estimated value of the stray inductance and the rate of change of the state variable. This not only conforms to the normal operating logic of the loop, but also ensures that the parameters used are parameters that are convenient to obtain in real time, and can also ensure that the estimated value of the stray inductance is associated with the rate of change of the state variable.

[0033] The function for determining the rate of change of the estimated value of stray inductance based on the sliding surface is determined by multiplying a set positive adjustment coefficient with a sign function corresponding to the positive or negative value of the difference between the actual value of the IGBT loop current and the state variable; or, the function for determining the rate of change of the estimated value of stray inductance based on the sliding surface is determined by multiplying a set negative adjustment coefficient with a sign function corresponding to the positive or negative value of the difference between the actual value of the IGBT loop current and the state variable.

[0034] In summary, under normal circumstances, the general form of the sliding film observer with the estimated value of the IGBT loop current as the state variable is:

[0035]

[0036] The Kirchhoff voltage equation determined based on the busbar capacitor voltage in the IGBT circuit and the equivalent voltages of the IGBT, load, and stray inductance is:

[0037]

[0038] in, is the rate of change of the IGBT loop current; U dc (t) is the busbar capacitor voltage in the IGBT circuit; U ce (t) is the equivalent voltage across the IGBT in the IGBT circuit; U d (t) is the equivalent voltage of the load in the GBT circuit; is the estimated value of stray inductance.

[0039] Combining the general form of the synovial observer with Kirchhoff's voltage equation, the synovial observer can be simplified to:

[0040]

[0041] In the formula, is the rate of change of the state variable (i.e., the rate of change of the estimated value of the IGBT loop current); U dc (t) is the busbar capacitor voltage in the IGBT circuit; U ce(t) is the equivalent voltage of the IGBT in the IGBT circuit; U d (t) is the equivalent voltage of the load in the GBT circuit; is the estimated value of stray inductance; g·sign(σ) is the sliding mode control term, where σ is the sliding surface, sign(σ) is the sign function of the sliding surface; g is the sliding mode control parameter.

[0042] In this embodiment, the sliding mode observer is used to track the state variable The system behavior can be observed in a targeted manner through a simplified sliding mode observer model without introducing a sliding mode control term in the sliding mode observer, which helps to clearly reflect the estimated main behavior without being disturbed by the complexity introduced by the control strategy; therefore, the function that is finally determined to determine the rate of change of the state variable based on the busbar capacitor voltage in the IGBT circuit and the estimated values ​​of the IGBT, load, and stray inductance is specifically:

[0043]

[0044] in, is the rate of change of the state variable (i.e., the rate of change of the estimated value of the IGBT loop current); U dc (t) is the busbar capacitor voltage in the IGBT circuit; U ce (t) is the equivalent voltage of the IGBT in the IGBT circuit; U d (t) is the equivalent voltage of the load in the GBT circuit; is the estimated value of stray inductance.

[0045] The function for determining the rate of change of the estimated stray inductance value according to the positive or negative of the sliding surface is determined by the product of the sign function corresponding to the difference between the actual value of the IGBT loop current and the state variable and the set positive adjustment coefficient; or, the function for determining the rate of change of the estimated stray inductance value according to the positive or negative of the sliding surface is determined by the product of the sign function corresponding to the positive or negative difference between the state variable and the actual value of the IGBT loop current and the set negative adjustment coefficient. Specifically, if the sliding surface determined according to the positive or negative difference between the actual value of the IGBT loop current and the state variable is:

[0046]

[0047] Where i is the actual value of the IGBT loop current, is a state variable; then the function for determining the rate of change of the estimated value of stray inductance according to the sliding surface can be:

[0048]

[0049] Among them, sign(σ) is the sign function of the sliding surface, and γ is the positive adjustment coefficient; since the positive and negative nature of the sign function is completely consistent with its parameter, if the sliding surface is determined based on the positive and negative difference between the actual value of the IGBT loop current and the state variable, it is:

[0050]

[0051] Then the function for determining the rate of change of the estimated value of stray inductance according to the sliding surface can be:

[0052]

[0053] Among them, sign(σ) is the sign function of the sliding surface, and λ is a negative adjustment coefficient. Specifically, in order to speed up the convergence speed and reduce the jitter phenomenon, the absolute values ​​of γ and λ can be taken as 0.01.

[0054] In this embodiment, the estimated value is updated in combination with the numerical integration principle of the Euler method, that is, the estimated value of the stray inductance is updated according to the estimated value of the stray inductance at the last set time step and the product of the rate of change of the estimated value of the stray inductance at the last set time step and the set time step value; the specific updating method includes:

[0055]

[0056] in, is the estimated value of stray inductance at the current set time step (i.e., when the estimated value of stray inductance is updated for the k+1th time); is the estimated value of stray inductance at the last set time step (i.e., when the estimated value of stray inductance is updated for the kth time); is the rate of change of the estimated value of stray inductance at the last set time step; Δt is the value of the set time step. Considering the dynamic characteristics of the system, the dynamic response speed of the power electronic circuit containing the stray inductance estimation is usually very fast, which requires the use of a smaller time step to accurately capture the rapid changes of current and voltage. In order to ensure that the observer can respond quickly to changes in the system state, a smaller time step is usually required. When using numerical integration methods such as the Euler method, the selection of the time step must take into account numerical stability. Too large a time step may lead to instability or divergence of the numerical solution, while too small a time step will lead to a significant increase in the amount of calculation. In addition, accuracy is also a consideration, and the time step needs to be small enough to ensure sufficient simulation accuracy. In this embodiment, the set time step is specifically set to 0.01s. By applying the above update method in each discrete set time step, the estimated value of stray inductance can be gradually adjusted and updated, and finally, on the basis of the set initial value, a stray inductance estimate that can be basically close to the actual value of the stray inductance is obtained after several set time steps.

[0057] The above-mentioned updating of the stray inductance estimation value and the state variable of the sliding film observer is repeated until the end of the set time period is reached. Finally, the stray inductance estimation value is fed back to the corresponding control system to realize closed-loop control of the control system.

[0058] To illustrate the effectiveness of the IGBT loop stray inductance identification method of this embodiment, a simulation verification is performed. The equivalent circuit topology structure using the IGBT loop stray inductance identification method is as follows: Figure 2 As shown, by Figure 2 It can be seen that the equivalent circuit topology involved in this identification method includes: busbar capacitor C dc , busbar equivalent stray inductance L ss , the switching device IGBT during the turn-on process, as well as the reverse diode and the load equivalent current source I in parallel with it load ; During this period, the busbar capacitance C dc The voltage on U dc , the equivalent voltage across the IGBT is U ce , then the load is connected in parallel with the reverse diode, so its equivalent voltage is U d .

[0059] The initial value of the stray inductance estimate during simulation is set to: L ss_actual =1.5 (i.e. set the initial value), U ce , U dc , U d The experimental data obtained from the experimental platform are then simulated in Matlab; the simulation results are as follows Figure 3 shown; according to Figure 3 It can be seen that the error between the estimated value and the true value of the stray inductance is basically within a reasonable range, indicating that the IGBT circuit stray inductance identification method is effective.

[0060] In other embodiments, the error of the IGBT circuit stray inductance identification method can be reduced by adaptively adjusting the sliding mode gain, optimizing the numerical integration method, increasing the sampling frequency or reducing the time step, and improving the sliding mode observer design, so as to adapt to different application environments and system characteristics. This adaptability and flexibility make the system have a wide range of application value in various practical application scenarios.

[0061] IGBT loop stray inductance identification system implementation example

[0062] This embodiment provides a technical solution for an IGBT circuit stray inductance identification system, including a processor, wherein the processor is used to execute a computer program to implement the steps of the IGBT circuit stray inductance identification method in the above-mentioned IGBT circuit stray inductance identification method embodiment.

[0063] Since the working principle and specific process of the IGBT circuit stray inductance identification system of this embodiment have been described in detail in the above-mentioned IGBT circuit stray inductance identification method embodiment, they will not be repeated here.

[0064] The present invention has the following characteristics:

[0065] 1) By taking the estimated value of the IGBT loop current as the state variable updated according to the sliding film observer, the change rate of the state variable is determined by the estimated value of the stray inductance and other voltages in the IGBT loop except the equivalent voltage of the stray inductance (busbar capacitor voltage and equivalent voltages of the IGBT and load), which is equivalent to constructing the relationship between the estimated value of the stray inductance and the change rate of the state variable by the voltage parameter that can be easily obtained in real time, thereby linking the state variable of the sliding mode observer with the estimated value of the stray inductance; on this basis, the difference between the actual value of the IGBT loop current and the state variable (the estimated value of the IGBT loop current) is taken as the sliding surface of the sliding film observer, and the estimated value of the stray inductance is updated according to the change rate of the estimated value of the stray inductance calculated by the sliding surface through the numerical integration principle of the Euler method, so that the sliding mode observer can be used to update the estimated value of the stray inductance. The nonlinear processing capability of the detector is utilized. By judging whether the estimated value of the IGBT loop current is larger or smaller than the actual value, the increase or decrease of the estimated value of the stray inductance is adaptively adjusted. The adjustment process is repeated multiple times within a set time period. The estimated value of the IGBT loop current can be ensured to be close to the actual value of the IGBT loop current while the estimated value of the stray inductance is made close to the actual value of the stray inductance, thereby ensuring the accuracy of the stray inductance identification result. This method utilizes the nonlinear processing capability of the sliding mode observer and only involves a few voltage parameters that are easier to obtain in real time. Therefore, it is ensured that a relatively accurate stray inductance estimation value can be obtained in a complex, nonlinear and uncertain power electronics and motor drive system environment. The method has stronger adaptability, does not require complex calculation or modeling processes, is less affected by external factors, and has better robustness.

[0066] 2) Perform stray inductance identification during the time period when the current change rate of the IGBT device in the IGBT circuit is the largest during the on-off process; the current in this time period is more linear and smooth than other times, and the current change is more obvious, which is the most suitable time period for stray inductance identification using the above-mentioned IGBT circuit stray inductance identification method that associates the rate of change of the estimated current value with the estimated stray inductance value.

[0067] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, but do not constitute a limitation to the present invention.

Claims

1. A method for identifying stray inductance of an IGBT circuit, characterized in that: Within a set time period, the stray inductance estimation value and the state variables of the sliding film observer are updated at every set time step; The state variable is an estimated value of the IGBT loop current, which is updated according to the sliding film observer; the sliding film observer includes a function for determining the rate of change of the state variable according to the estimated value of stray inductance, the busbar capacitor voltage in the IGBT loop, and the equivalent voltage of the IGBT and the load, and a function for determining the rate of change of the estimated value of stray inductance according to the positive or negative of the sliding surface; the sliding surface is determined according to the difference between the actual value of the IGBT loop current and the state variable; The stray inductance estimation value is updated based on the stray inductance estimation value at the last set time step and the product of the rate of change of the stray inductance estimation value at the last set time step and the set time step value; when the stray inductance estimation value is updated for the first time within the set time period, the set initial value is taken as the stray inductance estimation value at the last set time step.

2. The IGBT circuit stray inductance identification method according to claim 1, characterized in that: The set time period is a time period during which the current change rate of the IGBT device in the IGBT loop is the largest during the on and off process.

3. The IGBT circuit stray inductance identification method according to claim 1 or 2, characterized in that: The function that determines the rate of change of the estimated value of stray inductance according to the positive or negative of the sliding surface is determined by the product of a sign function corresponding to the difference between the actual value of the IGBT loop current and the state variable and a set positive adjustment coefficient; or, the function that determines the rate of change of the estimated value of stray inductance according to the positive or negative of the sliding surface is determined by the product of a sign function corresponding to the positive or negative difference between the state variable and the actual value of the IGBT loop current and a set negative adjustment coefficient.

4. The IGBT circuit stray inductance identification method according to claim 1 or 2, characterized in that: The function for determining the rate of change of the state variable according to the busbar capacitor voltage in the IGBT circuit and the estimated values ​​of the IGBT, load and stray inductance is obtained by the Kirchhoff voltage equation determined according to the busbar capacitor voltage in the IGBT circuit and the equivalent voltages of the IGBT, load and stray inductance, and the relationship between the equivalent voltage of the stray inductance and the rate of change of the state variable determined according to the estimated value of the stray inductance.

5. The IGBT circuit stray inductance identification method according to claim 1 or 2, characterized in that: Methods for updating the estimated stray inductance value according to the estimated stray inductance value at the last set time step and the product of the rate of change of the estimated stray inductance value at the last set time step and the set time step value include: in, It is the estimated value of stray inductance at the current set time step; is the estimated value of stray inductance at the last set time step; is the rate of change of the estimated value of stray inductance at the last set time step; Δt is the value of the set time step.

6. The IGBT circuit stray inductance identification method according to claim 1 or 2, characterized in that: The function of the rate of change of the state variable determined by the estimated value of stray inductance, the busbar capacitance voltage in the IGBT circuit, and the equivalent voltage of the IGBT and the load is: in, is the rate of change of state variables; U dc (t) is the busbar capacitor voltage in the IGBT circuit; U ce (t) is the equivalent voltage of the IGBT in the IGBT circuit; U d (t) is the equivalent voltage of the load in the GBT circuit; is the estimated value of stray inductance.

7. An IGBT loop stray inductance identification system, comprising a processor, characterized in that: The processor is used to execute a computer program to implement the steps of the IGBT loop stray inductance identification method according to any one of claims 1 to 6.

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