IGBT (Insulated Gate Bipolar Translator) driving circuit

Abstract

The embodiment of the invention discloses an IGBT driving circuit, and relates to the technical field of IGBT driving, the IGBT driving circuit comprises a driving power supply, a driving optocoupler and an IGBT, the driving power supply comprises a negative voltage output end, the negative voltage output end is connected with the driving optocoupler, and the driving optocoupler is connected with the IGBT; wherein after the driving power supply is powered off, the negative voltage overshoot level of the negative voltage output end of the driving power supply is smaller than a preset voltage threshold value. According to the invention, after the driving power supply is powered off, the negative voltage overshoot level output by the negative voltage output end of the driving power supply to the driving optocoupler is limited to be less than the preset voltage threshold (the voltage threshold can be 0.5 V for example), so that the driving optocoupler can be ensured not to switch on the IGBT by mistake due to the overhigh negative voltage overshoot level. Meanwhile, the negative voltage overshoot level output by the negative voltage output end of the driving power supply to the driving optocoupler is limited within the voltage threshold value, so that the false alarm fault of the driving optocoupler can be effectively avoided.

Description

Technical Field

[0001] The present invention relates to the field of IGBT driving technology, and in particular to an IGBT driving circuit. Background Art

[0002] IGBT (Insulate-Gate Bipolar Transistor) is the core component of electric drive equipment and is called the "trunk" of electric drive equipment. For frequency converters, inverters, and motor drive equipment, protecting IGBT from damage is the primary task of product reliability. Therefore, the reliability requirements for IGBT drive power circuits are more stringent.

[0003] There are many types of IGBT drive power supply topologies. For IGBT high-power drive power supplies, the single-ended flyback multi-channel output topology is commonly used. For IGBT, +15V is usually designed to turn on and -9V is turned off. In order to ensure the reliable turn-on of the IGBT and the stable level after turning on, the drive power supply usually adopts a stable positive voltage solution, that is, a +15V voltage regulator is used to output a stable +15V level for the secondary side 24V of the flyback power supply, and a negative voltage of -9V is generated at the same time to ensure the reliable turn-on and turn-off of the IGBT. For IGBT, the turn-on threshold voltage generally ranges from 4 to 6V. After the weak low-level PWM signal passes through the driver, it usually uses a direct drive or a push-to-close circuit to drive the IGBT to turn on and off.

[0004] For high-power frequency converters or inverters, their IGBT drivers usually use a driver optocoupler to directly drive or add a push-pull circuit to drive the IGBT to turn on and off, and this type of driver optocoupler has various protection functions (such as: Vce protection, undervoltage protection, overcurrent protection, etc.). Common driver optocouplers for IGBT drivers include ACPL-352J, ACPL-332J, ACPL-330J, QCPL-329 series, Naxinwei-NSI68515 series, etc. The inventors of this application have found that the above-mentioned driver optocouplers often have abnormal outputs after the driving power supply is cut off, causing the IGBT to be mistakenly turned on, thereby damaging the machine. Summary of the invention

[0005] The present invention provides an IGBT driving circuit to solve the problem that abnormal output of a driving optical coupler causes erroneous switching on of the IGBT after a driving power source is powered off.

[0006] The present invention provides an IGBT driving circuit, comprising a driving power supply, a driving optocoupler and an IGBT, wherein the driving power supply comprises a negative voltage output terminal, the negative voltage output terminal is connected to the driving optocoupler, and the driving optocoupler is connected to the IGBT; wherein, after the driving power supply is powered off, the negative voltage overshoot level of the negative voltage output terminal of the driving power supply is less than a preset voltage threshold.

[0007] Its further technical solution is that the driving power supply includes a power module, a voltage regulator, a first resistor, a first capacitor and a second capacitor, the negative electrode of the voltage regulator is connected to the power module, the positive electrode of the voltage regulator is connected to the first resistor, the first resistor is connected to the power module, the first capacitor is connected to the voltage regulator in parallel, and the second capacitor is connected to the first resistor in parallel.

[0008] Its further technical solution is that the negative pole of the voltage regulator tube leads to a positive voltage output end, the positive pole of the voltage regulator tube leads to a zero voltage output end, the end of the first resistor connected to the power module leads to the negative voltage output end, and the positive voltage output end and the zero voltage output end are both connected to the driving optocoupler.

[0009] Its further technical solution is that the driving power supply also includes a second resistor and a first diode; one end of the second resistor is connected to the negative electrode of the voltage regulator tube, and the other end of the second resistor is connected to the first resistor; the positive electrode of the first diode is connected to the first resistor, and the negative electrode of the first diode is connected to the positive electrode of the voltage regulator tube.

[0010] A further technical solution is that the conduction voltage drop of the first diode is smaller than the voltage threshold.

[0011] A further technical solution is that the driving power supply also includes a second diode, the anode of the second diode is connected to the power module, and the cathode of the second diode is connected to the cathode of the voltage regulator tube.

[0012] A further technical solution is that the driving power supply also includes a third capacitor and a fourth capacitor, the third capacitor is connected in parallel with the voltage regulator tube, and the fourth capacitor is connected in parallel with the first resistor.

[0013] A further technical solution is that the power module includes a transformer, and a secondary side of the transformer is connected to the negative electrode of the voltage regulator tube and the first resistor.

[0014] A further technical solution is that the IGBT driving circuit further includes a PWM signal output unit, and the PWM signal output unit is connected to the driving optical coupler.

[0015] A further technical solution is that the IGBT driving circuit also includes a push-pull circuit, and the driving optocoupler is connected to the IGBT via the push-pull circuit.

[0016] The above technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:

[0017] In the technical solution of the embodiment of the present invention, the IGBT driving circuit includes a driving power supply, a driving optocoupler and an IGBT, wherein the driving power supply includes a negative voltage output terminal, the negative voltage output terminal is connected to the driving optocoupler, and the driving optocoupler is connected to the IGBT; wherein, after the driving power supply is powered off, the negative voltage overshoot level of the negative voltage output terminal of the driving power supply is less than a preset voltage threshold. The present invention can limit the negative voltage overshoot level of the negative voltage output terminal of the driving power supply outputted to the driving optocoupler to be less than a preset voltage threshold (the voltage threshold can be, for example, 0.5V) after the driving power supply is powered off, thereby ensuring that the driving optocoupler will not mistakenly turn on the IGBT due to the excessively high negative voltage overshoot level. At the same time, by limiting the negative voltage overshoot level of the negative voltage output terminal of the driving power supply outputted to the driving optocoupler to within the voltage threshold, the driving optocoupler can also effectively avoid false alarm faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0021] Figure 1 A circuit principle block diagram of an IGBT driving circuit provided by an embodiment of the present invention;

[0022] Figure 2 A circuit principle block diagram of an IGBT driving circuit provided by another embodiment of the present invention;

[0023] Figure 3 A circuit diagram of a driving power supply of an IGBT driving circuit provided by an embodiment of the present invention;

[0024] Figure 4 A circuit diagram of a driving power supply of an IGBT driving circuit provided in another embodiment of the present invention.

[0025] Description of reference numerals:

[0026] Driving power supply 10, driving optocoupler 20, IGBT30, PWM signal output unit 40, push-pull circuit 50, negative voltage output terminal UH-, positive voltage output terminal UHG, zero voltage output terminal UH0, voltage regulator Z1, first resistor R1, first capacitor C1, second capacitor C2, second resistor R2, first diode D1, second diode D2, third capacitor C3, fourth capacitor C4, transformer T1. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments 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 part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0029] For ease of description, spatial relative terms may be used herein to describe the relative positional relationship or movement of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure undergoes a position flip or a posture change or a motion state change, then these directional indications also change accordingly, for example: an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used herein are interpreted accordingly.

[0030] In order to solve the technical problem in the prior art that after the driving power supply is cut off, the driving optocoupler has an abnormal output, which causes the IGBT to be mistakenly turned on, the present invention provides an IGBT driving circuit, which can limit the negative voltage overshoot level of the negative voltage output end of the driving power supply to the driving optocoupler to be less than a preset voltage threshold (the voltage threshold may be, for example, 0.5V) after the driving power supply is cut off, thereby ensuring that the driving optocoupler will not mistakenly turn on the IGBT and effectively avoiding false alarm faults of the driving optocoupler.

[0031] See also Figure 1-Figure 4 , is an IGBT driving circuit provided by an embodiment of the present invention, the IGBT driving circuit includes a driving power supply 10, a driving optical coupler 20 and an IGBT 30, and the specific structure is described as follows:

[0032] The driving power supply 10 is used to output a reference voltage to the driving optocoupler 20. Specifically, the driving power supply 10 includes a negative voltage output terminal UH-, a zero voltage output terminal UH0, and a positive voltage output terminal UHG; the negative voltage output terminal UH-, the zero voltage output terminal UH0, and the positive voltage output terminal UHG are all connected to the driving optocoupler 20. Among them, the positive voltage output terminal UHG is used to output a positive reference voltage to the optocoupler, such as +15V; the negative voltage output terminal UH- is used to output a negative reference voltage to the optocoupler, such as -9V. The zero voltage output terminal UH0 is used to output a 0-level reference voltage.

[0033] The driving optocoupler 20 is connected to the IGBT 30 and is used to drive the IGBT 30 to turn on or off. In some embodiments, the driving optocoupler 20 drives the IGBT 30 in a direct drive mode, that is, the driving optocoupler 20 is directly connected to the IGBT 30 and drives it.

[0034] In some other embodiments, the IGBT driving circuit further includes a push-pull circuit 50, the driving optocoupler 20 is connected to the IGBT 30 via the push-pull circuit 50, and the driving optocoupler 20 uses a push-pull mode to drive the IGBT 30. The push-pull circuit 50 may be composed of two switch tubes, which is not specifically limited in the present invention.

[0035] Further, the IGBT driving circuit further includes a PWM signal output unit 40, and the PWM signal output unit 40 is connected to the driving optocoupler 20. The PWM signal output unit 40 is used to output a PWM signal to the driving optocoupler 20. The PWM signal output unit 40 may be, for example, an IC chip capable of outputting a PWM signal, which is not specifically limited in the present invention.

[0036] In the embodiment of the present invention, in order to prevent the driving optocoupler 20 from mistakenly turning on the IGBT30, after the driving power supply 10 is powered off, the negative voltage overshoot level of the negative voltage output terminal UH- of the driving power supply 10 is less than a preset voltage threshold, and the voltage threshold may be, for example, 0.5V, that is, after the driving power supply 10 is powered off, the negative voltage overshoot level of the negative voltage output terminal UH- of the driving power supply 10 output to the driving optocoupler 20 is less than 0.5V, thereby ensuring that the driving optocoupler 20 will not mistakenly turn on the IGBT30.

[0037] At the same time, by limiting the negative voltage overshoot level outputted from the negative voltage output terminal UH- of the driving power supply 10 to the driving optocoupler 20 to within 0.5V, it is also possible to effectively avoid the driving optocoupler 20 from falsely reporting a fault.

[0038] In the technical solution of the embodiment of the present invention, the IGBT driving circuit includes a driving power supply 10, a driving optocoupler 20 and an IGBT30, wherein the driving power supply 10 includes a negative voltage output terminal UH-, wherein the negative voltage output terminal UH- is connected to the driving optocoupler 20, and the driving optocoupler 20 is connected to the IGBT30; wherein, after the driving power supply 10 is powered off, the negative voltage overshoot level of the negative voltage output terminal UH- of the driving power supply 10 is less than a preset voltage threshold. The present invention can limit the negative voltage overshoot level outputted from the negative voltage output terminal UH- of the driving power supply 10 to the driving optocoupler 20 to be less than a preset voltage threshold (the voltage threshold can be, for example, 0.5V) after the driving power supply 10 is powered off, thereby ensuring that the driving optocoupler 20 will not mistakenly turn on the IGBT30 due to the excessively high negative voltage overshoot level. At the same time, by limiting the negative voltage overshoot level outputted from the negative voltage output terminal UH- of the driving power supply 10 to the driving optocoupler 20 within the voltage threshold, it can also effectively avoid the driving optocoupler 20 from falsely reporting a fault.

[0039] In the embodiment of the present invention, the driving power supply 10 has two circuit structures. The first circuit structure of the driving power supply 10 is as follows:

[0040] The driving power supply 10 includes a power module, a voltage regulator tube Z1, a first resistor R1, a first capacitor C1 and a second capacitor C2. The negative electrode of the voltage regulator tube Z1 is connected to the power module, the positive electrode of the voltage regulator tube Z1 is connected to the first resistor R1, the first resistor R1 is connected to the power module, the first capacitor C1 is connected in parallel with the voltage regulator tube Z1, and the second capacitor C2 is connected in parallel with the first resistor R1. Specifically, the first capacitor C1 and the second capacitor C2 can be 100uF electrolytic capacitors, which play a role in energy storage.

[0041] Furthermore, the negative electrode of the voltage regulator tube Z1 leads to a positive voltage output terminal UHG, the positive electrode of the voltage regulator tube Z1 leads to a zero voltage output terminal UH0, and one end of the first resistor R1 connected to the power module leads to the negative voltage output terminal UH-, and the negative voltage output terminal UH-, the positive voltage output terminal UHG and the zero voltage output terminal UH0 are all connected to the driving optical coupler 20. Among them, the positive voltage output terminal UHG is used to output a positive reference voltage to the optical coupler, for example, +15V; the negative voltage output terminal UH- is used to output a negative reference voltage to the optical coupler, for example, -9V. The zero voltage output terminal UH0 is used to output a 0-level reference voltage.

[0042] Furthermore, the driving power supply 10 further includes a second diode D2, the anode of the second diode D2 is connected to the power module, and the cathode of the second diode D2 is connected to the cathode of the voltage regulator tube Z1. Specifically, the second diode D2 can ensure unidirectional current flow, thereby improving the safety of the circuit.

[0043] Furthermore, the driving power supply 10 further includes a third capacitor C3 and a fourth capacitor C4, wherein the third capacitor C3 is connected in parallel with the voltage regulator tube Z1, and the fourth capacitor C4 is connected in parallel with the first resistor R1. Specifically, the third capacitor C3 and the fourth capacitor C4 are 100pF ceramic capacitors, which have the function of high-frequency filtering, can filter out clutter in the circuit, and improve the stability of the circuit.

[0044] Further, the power module includes a transformer T1, and the secondary side of the transformer T1 is connected to the negative electrode of the voltage regulator tube Z1 and the first resistor R1. It can be understood that the primary side of the transformer T1 is used to connect to the power output module, and the power output module is used to output power, which is not specifically limited by the present invention. The transformer T1 has an isolation function to improve the safety of the circuit.

[0045] The working principle of the first circuit structure of the driving power supply 10 is as follows:

[0046] After the driving power supply 10 is powered off, the second capacitor C2 has only one discharge path, namely, the RC discharge path formed by the second capacitor C2 and the first resistor R1, and the voltage of the first capacitor C1 remains unchanged. At this time, the negative voltage slowly changes from -9V to 0V without overshoot. This solution can ensure that UHO-UH-≤0.5V, thereby ensuring that the driving optical coupler 20 will not mistakenly turn on the IGBT30. Among them, UHO is the voltage output by the zero voltage output terminal UH0, and UH- is the voltage output by the negative voltage output terminal UH-. This solution is suitable for an open-loop power supply solution or a primary feedback power supply solution.

[0047] In the embodiment of the present invention, the second circuit structure of the driving power supply 10 is as follows:

[0048] The second circuit structure of the driving power supply 10 is based on the first circuit structure of the above-mentioned driving power supply 10, and adds a second resistor R2 and a first diode D1, wherein one end of the second resistor R2 is connected to the cathode of the voltage-stabilizing tube Z1, and the other end of the second resistor R2 is connected to the first resistor R1; the anode of the first diode D1 is connected to the first resistor R1, and the cathode of the first diode D1 is connected to the anode of the voltage-stabilizing tube Z1.

[0049] Specifically, the conduction voltage drop of the first diode D1 is less than the voltage threshold, and the voltage threshold may be 0.5 V. The first diode D1 may be specifically a Schottky diode with a low conduction voltage drop (a conduction voltage drop less than 0.5 V).

[0050] The working principle of the second circuit structure of the driving power supply 10 is as follows:

[0051] After the driving power supply 10 is powered off, since the first diode D1 is connected in parallel to the negative voltage of the driving power supply 10, the conduction voltage drop of the first diode D1 is less than 0.5V, so that the negative voltage can be clamped within the conduction voltage drop of the Schottky diode, that is, this solution can ensure that UHO-UH-≤0.5V, thereby ensuring that the driving optical coupler 20 will not mistakenly turn on the IGBT30. Wherein UHO is the voltage output by the zero voltage output terminal UH0, and UH- is the voltage output by the negative voltage output terminal UH-.

[0052] Furthermore, the model of the driving optocoupler 20 can be ACPL-352J, ACPL-332J, ACPL-330J, QCPL-329 series, Naxinwei-NSI68515 series, etc., which are not specifically limited by the present invention. The inventors have found that the above-mentioned driving optocoupler 20 requires that in the driving power supply 10, UHO-UH-≤0.5V, where UHO is the voltage output by the zero voltage output terminal UH0, and UH- is the voltage output by the negative voltage output terminal UH-; otherwise, the driving optocoupler 10 will output abnormalities, and the first abnormality is that its Vout pin outputs a high level, and the voltage is greater than 6V, which will turn on the IGBT and there is a risk of false turn-on; the second abnormality is that the fault feedback Fault pin of the driving optocoupler 20 outputs a high level, reporting a driver fault.

[0053] The technical solution of the present invention can limit the negative voltage overshoot level outputted from the negative voltage output terminal UH- of the driving power supply 10 to the driving optocoupler 20 to be less than a preset voltage threshold (the voltage threshold may be, for example, 0.5V) after the driving power supply 10 is powered off, thereby ensuring that the driving optocoupler 20 will not mistakenly turn on the IGBT 30 due to the excessively high negative voltage overshoot level. At the same time, by limiting the negative voltage overshoot level outputted from the negative voltage output terminal UH- of the driving power supply 10 to the driving optocoupler 20 to within the voltage threshold, it is also possible to effectively avoid the driving optocoupler 20 from falsely reporting a fault.

[0054] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0056] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0057] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0060] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0061] The above is a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An IGBT driving circuit, characterized in that: It includes a driving power supply, a driving optocoupler and an IGBT, wherein the driving power supply includes a negative voltage output terminal, the negative voltage output terminal is connected to the driving optocoupler, and the driving optocoupler is connected to the IGBT; wherein, after the driving power supply is powered off, the negative voltage overshoot level of the negative voltage output terminal of the driving power supply is less than a preset voltage threshold.

2. The IGBT driving circuit according to claim 1, characterized in that: The driving power supply includes a power module, a voltage regulator, a first resistor, a first capacitor and a second capacitor. The negative electrode of the voltage regulator is connected to the power module, the positive electrode of the voltage regulator is connected to the first resistor, the first resistor is connected to the power module, the first capacitor is connected to the voltage regulator in parallel, and the second capacitor is connected to the first resistor in parallel.

3. The IGBT driving circuit according to claim 2, characterized in that: The negative pole of the voltage regulator tube leads to a positive voltage output end, the positive pole of the voltage regulator tube leads to a zero voltage output end, the end of the first resistor connected to the power module leads to the negative voltage output end, and the positive voltage output end and the zero voltage output end are both connected to the driving optocoupler.

4. The IGBT driving circuit according to claim 2, characterized in that: The driving power supply also includes a second resistor and a first diode; one end of the second resistor is connected to the negative electrode of the voltage regulator tube, and the other end of the second resistor is connected to the first resistor; the positive electrode of the first diode is connected to the first resistor, and the negative electrode of the first diode is connected to the positive electrode of the voltage regulator tube.

5. The IGBT driving circuit according to claim 4, characterized in that: A conduction voltage drop of the first diode is smaller than the voltage threshold.

6. The IGBT driving circuit according to claim 2, characterized in that: The driving power supply further includes a second diode, the anode of the second diode is connected to the power module, and the cathode of the second diode is connected to the cathode of the voltage regulator tube.

7. The IGBT driving circuit according to claim 2, characterized in that: The driving power supply further includes a third capacitor and a fourth capacitor, the third capacitor is connected in parallel with the voltage regulator tube, and the fourth capacitor is connected in parallel with the first resistor.

8. The IGBT driving circuit according to claim 2, characterized in that: The power module includes a transformer, and the secondary side of the transformer is connected to the negative electrode of the voltage regulator tube and the first resistor.

9. The IGBT driving circuit according to claim 1, characterized in that: The IGBT driving circuit further includes a PWM signal output unit, and the PWM signal output unit is connected to the driving optical coupler.

10. The IGBT driving circuit according to claim 1, characterized in that: The IGBT driving circuit also includes a push-pull circuit, and the driving optocoupler is connected to the IGBT via the push-pull circuit.

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