An igbt drive module emi modeling method

Abstract

The application discloses an IGBT drive module EMI modeling method, comprising the following steps: positioning IGBT collector-heat sink, IGBT emitter-heat sink, IGBT gate-heat sink impedance test position, testing the impedance of each port, obtaining the parasitic parameters of IGBT poles to the heat sink, on the basis of the established IGBT model, adding IGBT collector-heat sink capacitance and the parasitic parameters of IGBT poles to the heat sink to establish an IGBT drive module EMI model, and providing assistance when a product containing IGBT is subjected to electromagnetic compatibility simulation and analysis in the early stage. Compared with the traditional technology, the method introduces the parasitic parameters of IGBT poles to the heat sink, can improve the accuracy of IGBT drive board EMI modeling, and provides a more accurate IGBT EMI model for electromagnetic compatibility simulation and analysis of a product containing IGBT in the early stage.

Description

Technical Field

[0001] This invention relates to the field of IGBT modeling methods, and more specifically, to an EMI modeling method for IGBT driver modules. Background Technology

[0002] An IGBT (Insulated Gate Bipolar Transistor) is a composite, fully controllable, voltage-driven power semiconductor device composed of a BJT (Bipolar Junction Transistor) and a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). It combines the advantages of a MOSFET's high input impedance and a GTR's low on-state voltage drop. GTRs have a low saturation voltage drop and high current density, but require a large drive current; MOSFETs have very low drive power and fast switching speed, but a large on-state voltage drop and low current density. IGBTs combine the advantages of both devices, offering low drive power and a low saturation voltage drop. They are ideally suited for applications in DC power conversion systems of 600V and above, such as AC motors, frequency converters, switching power supplies, lighting circuits, and traction drives.

[0003] As switching transistors, IGBTs are highly susceptible to electromagnetic interference due to rapidly changing voltage and current. Furthermore, IGBTs often operate under high current and high voltage, generating heat during operation. This results in high temperatures for the IGBT drive system. To ensure normal operation and extend the lifespan of the IGBTs, a heatsink is needed to maintain their operating temperature within a stable range. This inevitably introduces parasitic capacitance between the IGBT and the heatsink. High-frequency interference generated by the IGBT propagates primarily through the common-mode path provided by this parasitic capacitance. If this high-frequency path is not considered when modeling the IGBT, the EMC simulation results of electronic systems containing IGBT components will be inaccurate.

[0004] Existing technology discloses a broadband modeling method suitable for high-power IGBTs. It proposes measuring the impedance characteristics between the collector and emitter of an IGBT module under different forward bias voltages and recording the impedance characteristic curves. A vector fitting method is used to calculate the circuit parameters between the collector and emitter and construct an equivalent circuit. The drawback of this method is that while it establishes an equivalent circuit between the collector and emitter of the IGBT module, it cannot establish equivalent circuits between the IGBT ports and the heatsink. Therefore, it cannot provide a common-mode path for high-frequency interference generated by the IGBT, and thus cannot improve the accuracy of IGBT modeling compared to this patent.

[0005] The prior art also discloses an IGBT model for computer simulation of electromagnetic interference, including an IGBT forward conduction section model and an anti-parallel diode section model, both of which together contain a resistor R.c35 and capacitor C 35 The method uses a series-connected branch. Its drawback is that while it models the IGBT behavior in power electronic equipment and system EMI simulation prediction, including the IGBT forward conduction section and the anti-parallel diode section, it doesn't consider the use of heat sinks in actual IGBT applications. Therefore, it doesn't account for the parasitic parameters and equivalent circuitry between the IGBT and the heat sink, failing to improve the accuracy of IGBT modeling.

[0006] Therefore, in light of the above requirements and the shortcomings of existing technologies, this application proposes an EMI modeling method for IGBT driver modules. Summary of the Invention

[0007] This invention provides an EMI modeling method for IGBT driver modules, which introduces parasitic parameters of each IGBT electrode to the heat sink, thereby improving the accuracy of EMI modeling of IGBT driver boards and providing a more accurate EMI model of IGBTs for products containing IGBTs in the early stages of electromagnetic compatibility simulation and analysis.

[0008] The primary objective of this invention is to solve the aforementioned technical problems. The technical solution of this invention is as follows:

[0009] The first aspect of this invention provides an EMI modeling method for an IGBT driver module, which includes the following steps:

[0010] S1. According to the IGBT datasheet, locate the impedance test positions of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink on one bridge arm and perform impedance analysis to obtain the impedance parameters of each electrode heat sink.

[0011] S2. Calculate the parasitic parameters of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink based on the impedance parameters.

[0012] S3. Based on the obtained parasitic parameters, construct an impedance simulation circuit for the heat sink of any one of the collector, emitter, and gate electrodes of the IGBT.

[0013] S4. Obtain the impedance test results of the selected electrode to ground through impedance testing. Perform simulation verification on the impedance simulation circuit based on the impedance test results. If the verification is successful, proceed to the next step. If the verification fails, repeat step S3.

[0014] S5. Repeat steps S3 and S4 until all parasitic parameters on the bridge arm have been calculated and verified.

[0015] S6. Repeat steps S1-S5 to complete the parasitic parameter calculation for all bridge arms. Input the parasitic parameters of all bridge arms into the circuit simulation software to establish the EMI model of the IGBT driver module.

[0016] Furthermore, the IGBT driver module EMI model includes three bridge arms, each of which includes two IGBT modules, for a total of six IGBT modules; the IGBT driver module EMI model distributes the six IGBT drive signals to the gate of each IGBT module.

[0017] Furthermore, the impedance analysis in step S1 specifically involves: using an impedance analyzer to test the impedance parameters of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink; specifically: calibrating the open-circuit, short-circuit, and high-frequency characteristics of the impedance analyzer, setting the impedance test scan parameters, setting the probe end of the impedance analyzer to the target port, and obtaining the impedance amplitude-frequency characteristic curve F-|Z| and the phase-frequency characteristic curve F-Phase.

[0018] Furthermore, the impedance test scanning parameters include: setting the sweep frequency range to 20Hz-108MHz, setting the sweep frequency points to 1600, and setting the logarithmic scan mode.

[0019] Furthermore, the parasitic parameters include parasitic capacitance, parasitic inductance, and parasitic resistance.

[0020] Furthermore, the parasitic capacitance is calculated as follows:

[0021] C C1-GND =1 / (2πf1Z1)

[0022] Among them, C C1-GND f1 is the parasitic capacitance value; f1 is the frequency closest to -90° in the impedance amplitude-frequency characteristic curve F-|Z|; Z1 is the impedance amplitude closest to -90° in the impedance amplitude-frequency characteristic curve F-|Z|.

[0023] Furthermore, the specific calculation method for the parasitic resistance and parasitic inductance is as follows:

[0024] R C1-GND =Z2Ω

[0025] L C1-GND =((1 / (2πf2))^2) / C C1-GND

[0026] Among them, R C1-GND C is the parasitic resistance value, which is the impedance amplitude when the impedance phase angle is -180°; C1-GNDf2 is the parasitic capacitance value; f2 is the frequency closest to 180° in the impedance amplitude-frequency characteristic curve F-|Z|; Z2 is the impedance amplitude closest to 180° in the impedance amplitude-frequency characteristic curve F-|Z|.

[0027] Furthermore, steps S3 and S4 specifically involve: inputting the measured parasitic parameters into circuit simulation software, building an impedance simulation circuit and performing simulation tests, and comparing the simulation results with the impedance test results; if the comparison error is less than a preset value, proceed to the next step; if the comparison error is greater than a preset value, check whether there is an error between the impedance test process and the simulation process, and retest and compare until the comparison error is less than the preset value.

[0028] Furthermore, step S6 specifically involves: after completing the impedance detection of each port of the six IGBT modules in the three bridge arms to the heat sink, calculating the parasitic parameters and verifying them, inputting the parasitic parameters into the circuit simulation software, and distributing the six IGBT drive signals as inputs to the gate of each IGBT module to complete the establishment of the EMI model of the IGBT drive module.

[0029] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0030] This invention provides an EMI modeling method for IGBT driver modules. Based on the IGBT datasheet, the impedance test locations for the IGBT collector-heatsink, IGBT emitter-heatsink, and IGBT gate-heatsink are determined. An impedance analyzer is used to test the impedance at each port. The parasitic capacitance, parasitic inductance, and parasitic resistance of each IGBT terminal to the heatsink are obtained using capacitance calculation formulas and RLC resonance calculation formulas. Based on the established IGBT model, the IGBT collector-heatsink capacitance and parasitic parameters of each IGBT terminal to the heatsink are added to establish an EMI model for the IGBT driver module. This provides assistance for the early electromagnetic compatibility simulation and analysis of products containing IGBTs. Attached Figure Description

[0031] Figure 1 This is a flowchart of an EMI modeling method for an IGBT driver module according to the present invention.

[0032] Figure 2 This is a schematic diagram illustrating impedance detection in one embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of the parasitic parameter structure of an IGBT module on a bridge arm of the present invention for the heat sink.

[0034] Figure 4 This is an impedance characteristic curve of the collector c1 and the heat sink GND position in one embodiment of the present invention.

[0035] Figure 5 This is a simulation circuit for the impedance of the IGBT gate to ground in one embodiment of the present invention.

[0036] Figure 6 This is a comparison chart of the simulation results of the gate impedance simulation circuit and the actual measured impedance characteristic curve in one embodiment of the present invention.

[0037] Figure 7 This is a schematic diagram of the EMI model of an IGBT driver module in one embodiment of the present invention. Detailed Implementation

[0038] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0039] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0040] Example 1

[0041] like Figure 1 As shown, this invention provides an EMI modeling method for IGBT driver modules, which includes the following steps:

[0042] S1. According to the IGBT datasheet, locate the impedance test positions of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink on one bridge arm and perform impedance analysis to obtain the impedance parameters of each electrode heat sink.

[0043] S2. Calculate the parasitic parameters of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink based on the impedance parameters.

[0044] S3. Based on the obtained parasitic parameters, construct an impedance simulation circuit for the heat sink of any one of the collector, emitter, and gate electrodes of the IGBT.

[0045] S4. Obtain the impedance test results of the selected electrode to ground through impedance testing. Perform simulation verification on the impedance simulation circuit based on the impedance test results. If the verification is successful, proceed to the next step. If the verification fails, repeat step S3.

[0046] S5. Repeat steps S3 and S4 until all parasitic parameters on the bridge arm have been calculated and verified.

[0047] S6. Repeat steps S1-S5 to complete the parasitic parameter calculation for all bridge arms. Input the parasitic parameters of all bridge arms into the circuit simulation software to establish the EMI model of the IGBT driver module.

[0048] Furthermore, the IGBT driver module EMI model includes three bridge arms, each of which includes two IGBT modules, for a total of six IGBT modules; the IGBT driver module EMI model distributes the six IGBT drive signals to the gate of each IGBT module.

[0049] Furthermore, such as Figure 2 As shown, the impedance analysis in step S1 specifically involves: using an impedance analyzer to test the impedance parameters of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink; specifically: calibrating the open-circuit, short-circuit, and high-frequency characteristics of the impedance analyzer, setting the impedance test scan parameters, setting the probe end of the impedance analyzer to the target port, and obtaining the impedance amplitude-frequency characteristic curve F-|Z| and the phase-frequency characteristic curve F-Phase.

[0050] In a specific embodiment, the testing process is as follows:

[0051] 1) Place the impedance analyzer on the workbench, install the matching fixture on the input channel of the impedance analyzer, fix it, connect the power supply, and turn on the machine.

[0052] 2) Open the probe end of the fixture and clamp the four types of calibration elements respectively, and automatically calibrate the open circuit, short circuit and high frequency characteristics of the fixture respectively. After the calibration is successful, proceed to the next step.

[0053] 3) Enter the impedance test interface, set the sweep frequency range to 20Hz-108MHz, the sweep frequency points to 1600 (the number of points is already at its maximum), and select logarithmic scan.

[0054] 4) Use the probe end of the clamp (the port is not distinguished by positive or negative) to clamp each target port and tighten it.

[0055] 5) At this point, the impedance test circuit is connected. Using the impedance analyzer, press the trigger key to start automatic scanning, acquire the impedance amplitude-frequency characteristic curve F-|Z| and phase-frequency characteristic curve F-Phase of each target test port, and save the data.

[0056] Furthermore, the impedance test scanning parameters include: setting the sweep frequency range to 20Hz-108MHz, setting the sweep frequency points to 1600, and setting the logarithmic scan mode.

[0057] In a specific embodiment, the impedance characteristic curve of the IGBT collector c1 on one bridge arm relative to the GND position of the heat sink is shown in the figure below. Figure 4As shown.

[0058] Furthermore, the parasitic parameters include parasitic capacitance, parasitic inductance, and parasitic resistance. The parasitic parameter structure of the IGBT module on one bridge arm relative to the heatsink is as follows: Figure 3 As shown.

[0059] Furthermore, the parasitic capacitance is calculated as follows:

[0060] C C1-GND =1 / (2πf1Z1)

[0061] Among them, C C1-GND f1 is the parasitic capacitance value; f1 is the frequency closest to -90° in the impedance amplitude-frequency characteristic curve F-|Z|; Z1 is the impedance amplitude closest to -90° in the impedance amplitude-frequency characteristic curve F-|Z|.

[0062] Furthermore, the specific calculation method for the parasitic resistance and parasitic inductance is as follows:

[0063] R C1-GND =Z2Ω

[0064] L C1-GND =((1 / (2πf2))^2) / C C1-GND

[0065] Among them, R C1-GND C is the parasitic resistance value, which is the impedance amplitude when the impedance phase angle is -180°; C1-GND f2 is the parasitic capacitance value; f2 is the frequency closest to 180° in the impedance amplitude-frequency characteristic curve F-|Z|; Z2 is the impedance amplitude closest to 180° in the impedance amplitude-frequency characteristic curve F-|Z|.

[0066] Furthermore, steps S3 and S4 specifically involve: inputting the measured parasitic parameters into circuit simulation software, building an impedance simulation circuit and performing simulation tests, and comparing the simulation results with the impedance test results; if the comparison error is less than a preset value, proceed to the next step; if the comparison error is greater than a preset value, check whether there is an error between the impedance test process and the simulation process, and retest and compare until the comparison error is less than the preset value.

[0067] Furthermore, step S6 specifically involves: after completing the impedance detection of each port of the six IGBT modules in the three bridge arms to the heat sink, calculating the parasitic parameters and verifying them, inputting the parasitic parameters into the circuit simulation software, and distributing the six IGBT drive signals as inputs to the gate of each IGBT module to complete the establishment of the EMI model of the IGBT drive module.

[0068] Example 2

[0069] Based on the above embodiment 1, combined with Figures 5-6 This embodiment details the comparison between the simulation results of the IGBT gate impedance simulation circuit on one of the bridge arms and the actual measured impedance characteristic curve.

[0070] In one specific embodiment, the parasitic parameters of the IGBT gate on one bridge arm are constructed as follows: Figure 5 The impedance simulation circuit shown is compared with the actual measured gate impedance characteristic curve after simulation. Figure 6 The comparison shown indicates that the curves roughly match, suggesting that the parasitic parameters used in the simulation are consistent with the actual situation.

[0071] Example 3

[0072] Based on the above embodiments 1 and 2, combined with Figure 7 This embodiment details the process of constructing the EMI model of the IGBT driver module.

[0073] The values ​​of all other parasitic parameters on one of the bridge arms are shown in the table below.

[0074]

[0075] This embodiment includes three bridge arms. The parasitic parameters of the other two bridge arms to the heat sink are the same as those of this bridge arm. These parasitic parameters are input into the circuit design software to distribute the six IGBT drive signals to the gate of each IGBT. Finally, the EMI model of the IGBT drive module is established, and a system is constructed as follows: Figure 7 The EMI model of the IGBT driver module is shown.

[0076] The icons in the accompanying drawings that depict the structural positional relationships are for illustrative purposes only and should not be construed as limiting this patent.

[0077] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An EMI modeling method for an IGBT driver module, characterized in that, Includes the following steps: S1. Locate the impedance test positions of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink on one bridge arm and perform impedance analysis to obtain the impedance parameters of each electrode heat sink. S2. Calculate the parasitic parameters of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink based on the impedance parameters; S3. Based on the obtained parasitic parameters, construct an impedance simulation circuit for the heat sink of any one of the collector, emitter, and gate of the IGBT. S4. Obtain the ground impedance test results of the selected electrode in step S3 through impedance testing. Perform simulation verification on the impedance simulation circuit based on the impedance test results. If the verification is successful, proceed to the next step. If the verification fails, repeat step S3. S5. Repeat steps S3 and S4 until all parasitic parameters on the bridge arm have been calculated and verified. S6. Repeat steps S1-S5 to complete the parasitic parameter calculation for all bridge arms. Input the parasitic parameters of all bridge arms into the circuit simulation software to establish the EMI model of the IGBT driver module.

2. The EMI modeling method for an IGBT driver module according to claim 1, characterized in that, The specific steps for locating the impedance test positions of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink on one bridge arm are as follows: according to the IGBT datasheet, locate the impedance test positions of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink on one bridge arm.

3. The EMI modeling method for an IGBT driver module according to claim 1, characterized in that, The IGBT driver module EMI model includes three bridge arms, each of which includes two IGBT modules, for a total of six IGBT modules; the IGBT driver module EMI model distributes the six IGBT drive signals to the gate of each IGBT module.

4. The EMI modeling method for an IGBT driver module according to claim 1, characterized in that, The impedance analysis in step S1 specifically involves: using an impedance analyzer to test the impedance parameters of the IGBT collector-heat sink, IGBT emitter-heat sink, and IGBT gate-heat sink; calibrating the open-circuit, short-circuit, and high-frequency characteristics of the impedance analyzer; setting the impedance test scan parameters; setting the probe of the impedance analyzer to the target port; and obtaining the impedance amplitude-frequency characteristic curve F-|Z| and the phase-frequency characteristic curve F-Phase.

5. The EMI modeling method for an IGBT driver module according to claim 4, characterized in that, The impedance test scanning parameters include: setting the sweep frequency range to 20Hz-108MHz, setting the sweep frequency points to 1600, and setting the logarithmic scan mode.

6. The EMI modeling method for an IGBT driver module according to claim 5, characterized in that, The parasitic parameters include parasitic capacitance, parasitic inductance, and parasitic resistance.

7. The EMI modeling method for an IGBT driver module according to claim 6, characterized in that, The parasitic capacitance is calculated as follows: C C1-GND =1 / (2πf1Z1) Among them, C C1-GND f1 is the parasitic capacitance value; f1 is the frequency closest to -90° in the impedance amplitude-frequency characteristic curve F-|Z|; Z1 is the impedance amplitude closest to -90° in the impedance amplitude-frequency characteristic curve F-|Z|.

8. The EMI modeling method for an IGBT driver module according to claim 7, characterized in that, The specific calculation method for the parasitic resistance and parasitic inductance is as follows: R C1-GND =Z2Ω L C1-GND =((1 / (2πf2))^2) / C C1-GND Among them, R C1-GND C is the parasitic resistance value, which is the impedance amplitude when the impedance phase angle is -180°; C1-GND f2 is the parasitic capacitance value; f2 is the frequency closest to 180° in the impedance amplitude-frequency characteristic curve F-|Z|; Z2 is the impedance amplitude closest to 180° in the impedance amplitude-frequency characteristic curve F-|Z|.

9. The EMI modeling method for an IGBT driver module according to claim 1, characterized in that, Specifically, steps S3 and S4 are as follows: input the measured parasitic parameters into the circuit simulation software, build the impedance simulation circuit and perform simulation test, and compare the simulation results with the impedance test results. If the comparison error is less than the preset value, proceed to the next step; If the comparison error is greater than the preset value, check whether there is an error between the impedance test process and the simulation process, and repeat the test and comparison until the comparison error is less than the preset value.

10. The EMI modeling method for an IGBT driver module according to claim 3, characterized in that, Step S6 specifically involves: after completing the impedance detection of each port of the six IGBT modules in the three bridge arms to the heat sink, calculating the parasitic parameters and verifying them, inputting the parasitic parameters into the circuit simulation software, and distributing the six IGBT drive signals as inputs to the gate of each IGBT module to complete the establishment of the EMI model of the IGBT drive module.

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