SiC MOSFET extended SOA measurement method considering crosstalk influence of half-bridge structure

Abstract

The invention discloses a SiC MOSFET extended SOA measurement method considering the crosstalk influence of a half-bridge structure, and belongs to the technical field of power semiconductors. The method comprises the following steps: giving a maximum forward crosstalk current value, and testing and establishing a mapping relation between maximum allowable bus voltage and bus voltage rise time under different grid resistance conditions; giving a maximum negative crosstalk voltage value, and testing and establishing a mapping relation between the maximum allowable bus voltage and the bus voltage drop time under different grid resistance conditions; and based on the mapping relation, establishing a positive crosstalk safe working area and a negative crosstalk safe working area, and forming a comprehensive crosstalk safe working area by taking the intersection of the two. According to the invention, the coverage of the dynamic overstress risk under the cooperative work of multiple devices is realized, the application stability and reliability of the SiC MOSFET in the half-bridge circuit are improved, and the technical problem that the traditional SOA evaluation is disjointed with the actual working condition is solved.

Description

Technical Field

[0001] The present invention relates to a SiC MOSFET extended SOA measurement method considering the influence of half-bridge structure crosstalk, and belongs to the technical field of power semiconductors. Background Art

[0002] As a third-generation wide-bandgap semiconductor power device, SiC MOSFETs (Silicon Carbide Metal Oxide Semiconductor Field-Effect Transistors) are gradually replacing traditional silicon-based devices (such as Si MOSFETs and IGBTs) in high-voltage, high-frequency power electronics systems such as renewable energy generation, electric vehicles, and aerospace due to their high switching speeds, high voltage resistance, and high-temperature operation. The half-bridge structure, the most fundamental power conversion topology in these applications, has a direct impact on overall system performance due to its reliability. However, the low threshold voltage and ultra-fast switching characteristics of SiC MOSFETs significantly exacerbate the crosstalk effect (i.e., the phenomenon of devices turning on inadvertently in the off state due to common-source inductive coupling) in half-bridge circuits, becoming a key factor restricting the safe operation of the devices.

[0003] In existing technologies, research on the crosstalk effect of SiC MOSFETs mainly focuses on mechanism analysis, physical modeling, and suppression technology development. For example, crosstalk risks can be reduced by optimizing drive circuit design, adding negative voltage shutdown, or adjusting layout and wiring.

[0004] However, none of these studies systematically considered the impact of crosstalk on the device's safe operating area (SOA). Traditional methods for measuring the safe operating area (SOA), a parameter that defines the boundary within which a power device must operate reliably under specific voltage, current, and temperature conditions, rely solely on the static or dynamic characteristics of a single device. This approach fails to account for the dynamic overstress risks associated with crosstalk when multiple devices operate in concert. Summary of the Invention

[0005] In order to solve the problems existing in the background technology, the present invention provides a SiC MOSFET extended SOA measurement method considering the influence of half-bridge structure crosstalk.

[0006] To achieve the above object, the present invention adopts the following technical solution: a method for measuring the extended SOA of a SiC MOSFET considering the crosstalk effect of a half-bridge structure, the method comprising the following steps:

[0007] S1: Given a maximum forward crosstalk current value, test and establish a mapping relationship between the maximum allowable bus voltage and the bus voltage rise time under different gate resistance conditions;

[0008] S2: Given a maximum negative crosstalk voltage value, test and establish a mapping relationship between the maximum allowable bus voltage and the bus voltage drop time under different gate resistance conditions;

[0009] S3: Based on the mapping relationship of S1, a positive crosstalk safe working area is established. Based on the mapping relationship of S2, a negative crosstalk safe working area is established. The combined crosstalk safe working area is formed by taking the intersection of the positive crosstalk safe working area and the negative crosstalk safe working area.

[0010] Furthermore, the S1 includes the following steps:

[0011] S101: Using the given maximum forward crosstalk current as a constraint, set different gate resistances and gradually increase the bus voltage under various gate resistance conditions until the crosstalk current reaches the maximum crosstalk current value. ;

[0012] S102: Record the gate resistance value, bus voltage value and bus voltage rise time at this time to obtain a mapping point set ,in , Indicates the Group forward gate resistance value, Indicates the The bus voltage value corresponding to the forward gate resistance of the group, Indicates the The bus voltage rise time corresponding to the group forward gate resistance.

[0013] Furthermore, the S2 includes the following steps:

[0014] S201: Using the given maximum negative crosstalk voltage as a constraint, set different gate resistances and gradually increase the bus voltage under various gate resistance conditions until the crosstalk voltage reaches the maximum negative crosstalk voltage. ;

[0015] S202: Record the gate resistance value, bus voltage value and bus voltage drop time at this time to obtain a mapping point set ,in , Indicates the Group negative gate resistance value, Indicates the The bus voltage value corresponding to the negative gate resistance of the group, Indicates the The bus voltage drop time corresponding to the negative gate resistance of the group.

[0016] Furthermore, the forward crosstalk safe operating area in S3 is determined by the forward drain-source voltage change rate under the maximum forward crosstalk current condition. The vertical axis is the forward gate resistance The curve defining the horizontal axis.

[0017] Furthermore, the forward drain-source voltage change rate The calculation formula is as follows:

[0018]

[0019] Furthermore, the negative crosstalk safe operating area in S3 is determined by the negative drain-source voltage change rate under the maximum negative crosstalk current condition. The vertical axis is the negative gate resistance The curve defining the horizontal axis.

[0020] Furthermore, the negative drain-source voltage change rate The calculation formula is as follows:

[0021]

[0022] Furthermore, the comprehensive crosstalk safe operating area in S3 is a closed two-dimensional interval enclosed by the bus voltage-gate resistance curve corresponding to the maximum positive crosstalk current and the bus voltage-gate resistance curve corresponding to the maximum negative crosstalk voltage.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] By giving the maximum crosstalk constraint condition, the present invention systematically tests and establishes the mapping relationship between gate resistance, bus voltage and voltage change time, quantifies the dynamic change rate of drain-source voltage under positive / negative crosstalk, and then delineates the boundaries of independent safe operating areas; by taking the intersection of the two to form a comprehensive crosstalk safe operating area, the dynamic overstress risk under the collaborative operation of multiple devices is covered, and clear guidance is provided for the design of key parameters such as bus voltage and gate resistance, which effectively improves the application stability and reliability of SiC MOSFET in half-bridge circuits and solves the technical problem of the disconnection between traditional SOA evaluation and actual working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a flow chart diagram of the present invention;

[0026] Figure 2 This is a physical diagram of the test platform on which the present invention is based;

[0027] Figure 3 This is a diagram showing the forward crosstalk safe operating area results of Example 1 of the present invention;

[0028] Figure 4 This is a diagram showing the negative crosstalk safe operating area results of Example 1 of the present invention;

[0029] Figure 5 This is a diagram showing the result of the comprehensive crosstalk safe operating area according to Example 1 of the present invention. DETAILED DESCRIPTION

[0030] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] A method for measuring an extended SOA of a SiC MOSFET considering the influence of crosstalk in a half-bridge structure is disclosed, the method comprising the following steps:

[0032] S1: Given a maximum forward crosstalk current value, test and establish a mapping relationship between the maximum allowable bus voltage and the bus voltage rise time under different gate resistance conditions;

[0033] S2: Given a maximum negative crosstalk voltage value, test and establish a mapping relationship between the maximum allowable bus voltage and the bus voltage drop time under different gate resistance conditions;

[0034] S3: Based on the mapping relationship of S1, a positive crosstalk safe working area is established. Based on the mapping relationship of S2, a negative crosstalk safe working area is established. The combined crosstalk safe working area is formed by taking the intersection of the positive crosstalk safe working area and the negative crosstalk safe working area.

[0035] Furthermore, the S1 includes the following steps:

[0036] S101: Using the given maximum forward crosstalk current as a constraint, set different gate resistances and gradually increase the bus voltage (5V increments per time interval of 1ms; or reference industry standards, such as the voltage regulation method in the double pulse test) under various gate resistance conditions until the crosstalk current reaches the maximum crosstalk current value. ;

[0037] S102: Record the gate resistance value, bus voltage value and bus voltage rise time at this time to obtain a mapping point set ,in , Indicates the Group forward gate resistance value, Indicates the The bus voltage value corresponding to the forward gate resistance of the group, Indicates the The bus voltage rise time corresponding to the group forward gate resistance.

[0038] Furthermore, the S2 includes the following steps:

[0039] S201: Using the given maximum negative crosstalk voltage as a constraint, set different gate resistances and gradually increase the bus voltage (5V increments per time interval of 1ms; or reference industry standards, such as the voltage regulation method in the double pulse test) under various gate resistance conditions until the crosstalk voltage reaches the maximum negative crosstalk voltage. ;

[0040] S202: Record the gate resistance value, bus voltage value and bus voltage drop time at this time to obtain a mapping point set ,in , Indicates the Group negative gate resistance value, Indicates the The bus voltage value corresponding to the negative gate resistance of the group, Indicates the The bus voltage drop time corresponding to the negative gate resistance of the group.

[0041] Furthermore, the forward crosstalk safe operating area in S3 is determined by the forward drain-source voltage change rate under the maximum forward crosstalk current condition. The vertical axis is the forward gate resistance The curve defining the horizontal axis.

[0042] Furthermore, the forward drain-source voltage change rate The calculation formula is as follows:

[0043]

[0044] Furthermore, the negative crosstalk safe operating area in S3 is determined by the negative drain-source voltage change rate under the maximum negative crosstalk current condition. The vertical axis is the negative gate resistance The curve defining the horizontal axis.

[0045] Furthermore, the negative drain-source voltage change rate The calculation formula is as follows:

[0046]

[0047] Furthermore, the comprehensive crosstalk safe operating area in S3 is a closed two-dimensional interval enclosed by the bus voltage-gate resistance curve corresponding to the maximum positive crosstalk current and the bus voltage-gate resistance curve corresponding to the maximum negative crosstalk voltage.

[0048] This invention defines the required ranges for gate resistance and drain-source voltage change for a half-bridge circuit under given positive crosstalk currents and negative crosstalk voltages. To facilitate design reference, this invention optimizes and merges the two aforementioned safe operating regions, designing a comprehensive crosstalk safe operating region using bus voltage and gate resistance as variables. In practical applications, the intersection of the traditional crosstalk operating region and the crosstalk safe operating region should be determined based on actual conditions to ensure safe and reliable operation of the half-bridge circuit.

[0049] The present invention comprehensively analyzes the influence of bus voltage and gate resistance to determine the positive crosstalk safe operating area and the negative crosstalk safe operating area. The positive crosstalk and negative crosstalk curves are comprehensively analyzed to determine the comprehensive crosstalk safe operating area.

[0050] The present invention provides a maximum forward crosstalk current value. , Maximum negative crosstalk voltage value , testing and establishing a mapping relationship, and calculating the positive crosstalk safe operating area, negative crosstalk safe operating area, and combined crosstalk safe operating area. This invention solves the technical problem that traditional safe operating areas in SiC MOSFET half-bridge circuits fail to consider the reliability risks caused by crosstalk effects. The safe areas defined by this invention can guide the design of parameters such as bus voltage and gate resistance, improving the stability of SiC MOSFET applications.

[0051] Example 1:

[0052] like Figure 3-5 As shown in Figure 1, the extended SOA of SiC MOSFET considering the crosstalk influence of the half-bridge structure includes the positive crosstalk safe operating area, the negative crosstalk safe operating area and the comprehensive crosstalk safe operating area.

[0053] like Figure 3 As shown, when the forward crosstalk current is given to be 3A, 4A and 5A respectively, a curve with the forward drain-source voltage change rate as the vertical axis and the forward gate resistance as the horizontal axis is drawn in combination with the measured data to obtain the forward crosstalk safe operating area.

[0054] like Figure 4 As shown, when the negative crosstalk voltages are given as -6.5V, -7.0V and -7.5V respectively, a curve with the negative drain-source voltage change rate as the vertical axis and the negative gate resistance as the horizontal axis is drawn in combination with the measured data to obtain the negative crosstalk safe operating area.

[0055] like Figure 5As shown, the present invention integrates and optimizes the aforementioned positive and negative safe operating areas to create a comprehensive crosstalk safe operating area. The comprehensive crosstalk safe operating area for a given positive crosstalk current and negative crosstalk voltage is a closed two-dimensional interval formed by two curves, with the bus voltage as the vertical axis and the gate resistance as the horizontal axis. Designers can obtain the desired closed two-dimensional interval by intersecting different curves based on specific application scenarios.

[0056] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0057] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for measuring the extended SOA of a SiC MOSFET considering the crosstalk effect of a half-bridge structure, characterized by: The method comprises the following steps: S1: Given a maximum forward crosstalk current value, test and establish a mapping relationship between the maximum allowable bus voltage and the bus voltage rise time under different gate resistance conditions; S2: Given a maximum negative crosstalk voltage value, test and establish a mapping relationship between the maximum allowable bus voltage and the bus voltage drop time under different gate resistance conditions; S3: Based on the mapping relationship of S1, a forward crosstalk safe working area is established; Based on the mapping relationship of S2, a negative crosstalk safe working area is established, and a comprehensive crosstalk safe working area is formed by taking the intersection of the positive crosstalk safe working area and the negative crosstalk safe working area.

2. The method for measuring an extended SOA of a SiC MOSFET considering the crosstalk effect of a half-bridge structure according to claim 1, characterized in that: The S1 comprises the following steps: S101: Using the given maximum forward crosstalk current as a constraint, set different gate resistances and gradually increase the bus voltage under various gate resistance conditions until the crosstalk current reaches the maximum crosstalk current value. ; S102: Record the gate resistance value, bus voltage value and bus voltage rise time at this time to obtain a mapping point set ,in , Indicates the Group forward gate resistance value, Indicates the The bus voltage value corresponding to the forward gate resistance of the group, Indicates the The bus voltage rise time corresponding to the group forward gate resistance.

3. The method for measuring an extended SOA of a SiC MOSFET considering the crosstalk effect of a half-bridge structure according to claim 2, wherein: The S2 comprises the following steps: S201: Using the given maximum negative crosstalk voltage as a constraint, set different gate resistances and gradually increase the bus voltage under various gate resistance conditions until the crosstalk voltage reaches the maximum negative crosstalk voltage. ; S202: Record the gate resistance value, bus voltage value and bus voltage drop time at this time to obtain a mapping point set ,in , Indicates the Group negative gate resistance value, Indicates the The bus voltage value corresponding to the negative gate resistance of the group, Indicates the The bus voltage drop time corresponding to the negative gate resistance of the group.

4. The method for measuring an extended SOA of a SiC MOSFET considering the crosstalk effect of a half-bridge structure according to claim 3, wherein: The forward crosstalk safe operating area described in S3 is determined by the forward drain-source voltage change rate under the maximum forward crosstalk current condition. The vertical axis is the forward gate resistance The curve defining the horizontal axis.

5. The method for measuring an extended SOA of a SiC MOSFET considering the crosstalk effect of a half-bridge structure according to claim 4, characterized in that: The forward drain-source voltage change rate The calculation formula is as follows: 。 6. The method for measuring an extended SOA of a SiC MOSFET considering the crosstalk effect of a half-bridge structure according to claim 5, characterized in that: The negative crosstalk safe operating area S3 is determined by the negative drain-source voltage change rate under the maximum negative crosstalk current condition. The vertical axis is the negative gate resistance The curve defining the horizontal axis.

7. The method for measuring an extended SOA of a SiC MOSFET considering the crosstalk effect of a half-bridge structure according to claim 6, characterized in that: The negative drain-source voltage change rate The calculation formula is as follows: 。 8. The method for measuring an extended SOA of a SiC MOSFET considering the crosstalk effect of a half-bridge structure according to claim 7, wherein: The comprehensive crosstalk safe operating area S3 is a closed two-dimensional interval surrounded by the bus voltage-gate resistance curve corresponding to the maximum positive crosstalk current and the bus voltage-gate resistance curve corresponding to the maximum negative crosstalk voltage.

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