CN110601509B

CN110601509B - IGBT drive protection circuit and fault protection method thereof

Info

Publication number: CN110601509B
Application number: CN201910967709.1A
Authority: CN
Inventors: 郭艳双; 谷雨; 李江松
Original assignee: Sungrow Power Supply Co Ltd
Current assignee: Sungrow Power Supply Co Ltd
Priority date: 2019-10-12
Filing date: 2019-10-12
Publication date: 2021-09-03
Anticipated expiration: 2039-10-12
Also published as: CN110601509A

Abstract

The invention provides an IGBT driving protection circuit and a fault protection method thereof, wherein the fault protection method of the IGBT driving protection circuit comprises the following steps: carrying out time sequence processing and soft turn-off on the IGBT under the condition that the system is determined to have a fault; then, within a first preset time, controlling the driving voltage of the IGBT to keep a first preset negative voltage, and ensuring that the IGBT is completely turned off; and then the driving voltage of the IGBT is controlled to be a preset PWM signal, the value of the preset PWM signal is zero level or second preset negative pressure, the second preset negative pressure is more than or equal to the first preset negative pressure, the duty ratio of the second preset negative pressure is more than or equal to zero, and the duty ratio of the zero level is more than zero, so that the temperature rise of the IGBT turn-off resistor caused by the fact that the driving voltage of the IGBT is kept at the negative pressure for a long time can be avoided, and the safety risk, the heating failure and the fault spreading risk caused by the temperature rise of the IGBT turn-off resistor are further avoided.

Description

IGBT drive protection circuit and fault protection method thereof

Technical Field

The invention relates to the technical field of power electronics, in particular to an IGBT driving protection circuit and a fault protection method thereof.

Background

With the continuous development of new energy markets, the application of multi-level technology is more and more mature particularly in high-power occasions. At present, for the IGBT (Insulated Gate Bipolar Transistor) driving of a multi-level circuit, a single driving board is mainly designed for driving, so as to facilitate plug and play and maintenance, and meanwhile, for the reliable driving of the IGBT, the digital control technology is more and more widely applied.

According to the existing IGBT driving circuit, a fault detection circuit uploads a fault signal to a driving board or an upper computer, then a digital control unit in the driving board makes protective measures on a system by judging whether the fault is true or false, and finally IGBT driving voltage is kept at negative pressure so as to guarantee the reliability of IGBT turn-off.

However, if the IGBT is short-circuited at the gate, the negative voltage received at the gate of the IGBT is short-circuited through the turn-off resistor thereof by the existing protection measures, and the temperature of the turn-off resistor thereof rises to 140 ℃ within several minutes, or even higher, which finally causes safety risks such as smoking and fire. Meanwhile, if the turn-off resistor fails, a power supply of the drive board is short-circuited, so that the temperature of a power supply circuit is increased, and the fault is further spread.

Disclosure of Invention

In view of this, embodiments of the present invention provide an IGBT driving protection circuit and a fault protection method thereof, so as to solve the problem in the prior art that a safety risk and a fault spreading risk cannot be avoided for a gate short-circuit fault.

In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:

the invention discloses a fault protection method of an IGBT drive protection circuit in a first aspect, which comprises the following steps:

carrying out time sequence processing and soft turn-off on the IGBT under the condition that the system is determined to have a fault;

controlling the driving voltage of the IGBT to be kept at a first preset negative voltage within a first preset time, and ensuring that the IGBT is completely turned off;

controlling the driving voltage of the IGBT to be a preset PWM signal; the value of the preset PWM signal is zero level or second preset negative pressure, the second preset negative pressure is more than or equal to the first preset negative pressure, the duty ratio of the second preset negative pressure is more than or equal to zero, and the duty ratio of the zero level is more than zero.

Optionally, in the fault protection method for the IGBT driving protection circuit described above, the duty ratio of the second preset negative voltage is equal to zero.

Optionally, in the fault protection method for the IGBT driving protection circuit described above, the second preset negative voltage is equal to the first preset negative voltage.

Optionally, in the fault protection method for the IGBT driving protection circuit, after controlling the driving voltage of the IGBT to be the preset PWM signal, the method further includes:

judging whether the fault is eliminated;

if the fault is eliminated, controlling the driving voltage of the IGBT to be kept at a third preset negative voltage within a second preset time;

and normally sending waves to the IGBT.

Optionally, in the fault protection method for the IGBT drive protection circuit, if the fault is eliminated, before controlling the drive voltage of the IGBT to be maintained at the third preset negative voltage, the method further includes:

and controlling the driving voltage of the IGBT to keep the preset PWM signal until the third preset time is over.

Optionally, in the fault protection method for the IGBT driving protection circuit described above, the third preset negative voltage is equal to the first preset negative voltage.

Optionally, in the fault protection method for the IGBT driving protection circuit described above, the soft turn-off is: a secondary shutdown, or a tertiary shutdown.

Optionally, in the fault protection method for the IGBT driving protection circuit, before performing the timing processing and the soft turn-off on the IGBT, the method further includes:

and judging whether the system has faults or not according to the received fault signal or fault return signal.

The second aspect of the present invention discloses an IGBT driving protection circuit, including:

the device comprises a digital control unit, a gate pole amplifying circuit, a soft turn-off circuit and a fault detection circuit; the digital control unit is respectively connected with the gate pole amplifying circuit, the soft turn-off circuit and the fault detection circuit;

the fault detection circuit is used for detecting the fault state of the system where the IGBT is located, and generating and outputting a fault signal according to the detection result;

the gate pole amplifying circuit is used for amplifying the normal driving signal of the IGBT according to the control of the digital control unit;

the soft turn-off circuit is used for realizing soft turn-off of the IGBT according to the control of the digital control unit;

the digital control unit is used for executing the fault protection method of the IGBT driving protection circuit.

Optionally, in the above IGBT driving protection circuit, the digital control unit is further configured to receive the fault signal, and determine whether a system fails or whether the fault is eliminated according to the fault signal.

Optionally, in the IGBT driving protection circuit, the digital control unit is further connected to an upper computer;

and the digital control unit is also used for receiving and generating a control input signal according to the fault signal, outputting the control input signal to the upper computer, and determining that the system has a fault or the fault is eliminated after receiving a fault return signal fed back by the upper computer.

Optionally, in the IGBT driving protection circuit described above, the IGBT driving protection circuit further includes:

and the blocking time setting unit is connected with the digital control unit and is used for setting a third preset time.

and the level mode setting unit is connected with the digital control unit and is used for setting the level mode of the IGBT.

and the state display unit is connected with the digital control unit and is used for displaying the state of the digital control unit and the working state of the IGBT driving circuit.

Based on the fault protection method of the IGBT drive protection circuit provided by the embodiment of the invention, the IGBT is subjected to time sequence processing and soft turn-off under the condition that the system is determined to have a fault; then, within a first preset time, controlling the driving voltage of the IGBT to keep a first preset negative voltage, and ensuring that the IGBT is completely turned off; and then the driving voltage of the IGBT is controlled to be a preset PWM signal, the value of the preset PWM signal is zero level or second preset negative pressure, the second preset negative pressure is more than or equal to the first preset negative pressure, the duty ratio of the second preset negative pressure is more than or equal to zero, and the duty ratio of the zero level is more than zero, so that the temperature rise of the IGBT turn-off resistor caused by the fact that the driving voltage of the IGBT is kept at the negative pressure for a long time is avoided, and the safety risk, the heating failure and the fault spreading risk caused by the temperature rise of the IGBT turn-off resistor are further avoided.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a flowchart of a fault protection method for an IGBT driving protection circuit according to an embodiment of the present application;

fig. 2 is a timing diagram of a fault protection method of an IGBT driving protection circuit according to an embodiment of the present application;

fig. 3 is a circuit diagram of an IGBT driving protection circuit provided in an embodiment of the present application;

fig. 4 is a timing diagram of another fault protection method for an IGBT driving protection circuit according to an embodiment of the present application;

fig. 5 is a flowchart of another fault protection method for an IGBT driving protection circuit according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of an IGBT driving protection circuit provided in an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The embodiment of the invention provides a fault protection method for an IGBT (insulated gate bipolar transistor) driving protection circuit, which aims to solve the problem that safety risk and fault spreading risk cannot be avoided for gate short circuit fault in the prior art.

With reference to fig. 1, fig. 2, fig. 4, and fig. 6, the method for protecting the IGBT driving protection circuit from faults mainly includes the following steps:

and S101, carrying out time sequence processing and soft turn-off on the IGBT under the condition that the system is determined to have a fault.

It should be noted that, in the IGBT driving protection circuit shown in fig. 6, the authenticity of the IGBT driving protection circuit can be determined according to the fault signal output by the fault detection circuit 604, so as to determine whether the system has a fault; specifically, the digital control unit 601 may directly perform the fault determination according to the fault signal; alternatively, the upper computer 605 may perform fault determination based on a fault signal forwarded by the digital control unit 601, and notify the digital control unit 601 by feeding back a fault return signal after determining the fault.

If the fault signal is true, and the low level in both fig. 2 and fig. 4 indicates that the fault signal is true, the first falling edge of the fault signal waveform in fig. 2 indicates the time when the system fails.

The purpose of carrying out the time sequence to IGBT lies in, avoids IGBT to bear full busbar voltage, causes IGBT overvoltage damage, and its concrete mode refers to prior art can, and it is no longer repeated here.

The aim of soft turn-off of the IGBT is to ensure that a voltage spike is effectively suppressed when the IGBT is turned off; in practice, two-level turn-off (such as the first two falling edges of the driving voltage waveform in fig. 2 and 4) or three-level turn-off (not shown) is often used, but not limited thereto.

For example, see fig. 3 for a two-level shutdown. When the fault detection circuit of the IGBT detects a fault, the digital control unit in the driving board firstly controls the driving voltage of the IGBT to be kept at a zero level, and then controls the driving voltage of the IGBT to be kept at a negative voltage after a period of time. The first falling edge of the drive voltage waveform in fig. 2 and 4 is delayed from the first falling edge of the fault signal waveform due to the time of fault judgment and the transfer time of the control information.

The third-level turn-off and the second-level turn-off are similar, and reference can be made to the related description of the second-level turn-off, so that the details are not repeated.

And S102, controlling the driving voltage of the IGBT to keep a first preset negative voltage within a first preset time, and ensuring that the IGBT is completely turned off.

Wherein the starting point of the first predetermined time is the ending point of the soft turn-off. The value of the first preset time can be determined according to the specific application environment, and only the requirement that the IGBT can be completely turned off is met.

Similarly, the value of the first preset negative pressure can be determined according to the specific application environment, and the IGBT can be completely turned off only by meeting the requirement. In order to avoid hardware modification of the IGBT driving protection circuit in the prior art, the first preset negative voltage takes the value of the negative voltage in the prior art (as shown in fig. 3).

The first predetermined time is represented in fig. 2 by an interval T1 between the third to fourth vertical imaginary lines, and the first preset negative pressure is represented by the driving voltage in an interval T1 between the third to fourth vertical imaginary lines.

And S103, controlling the driving voltage of the IGBT to be a preset PWM signal.

The value of the preset PWM signal is zero level or a second preset negative voltage, as shown in fig. 2.

The second preset negative pressure is greater than or equal to the first preset negative pressure, the duty ratio of the second preset negative pressure is greater than or equal to zero, and the duty ratio of zero level is greater than zero.

It should be noted that, the duty ratio of the zero level is greater than zero, that is, the drive voltage of the IGBT after complete shutdown is required to have a zero level value state, and even if a gate short-circuit fault occurs, the drive voltage received by the gate of the IGBT does not remain at a negative voltage for a long time, so that the temperature rise problem of the turn-off resistance of the IGBT caused by the fact that the IGBT is always maintained at a negative voltage can be alleviated.

When the duty ratio of the second preset negative pressure is larger than zero, the second preset negative pressure is larger than or equal to the first preset negative pressure, so that the negative pressure value of the driving voltage is equal to or lower than the negative pressure in the prior art; if the second predetermined negative voltage is greater than the first predetermined negative voltage, the effective value of the driving voltage can be further reduced based on the above effects; even if the first preset negative voltage and/or the negative voltage in the prior art are/is equal to the first preset negative voltage, as shown in fig. 2, the above-mentioned temperature rise problem can be alleviated by the duty ratio of the zero level being greater than zero, and no improvement on a hardware circuit and no increase in the cost of the system are required.

In practical application, after the driving voltage of the IGBT is controlled to be the preset PWM signal, if the duty ratio of the second preset negative voltage in the preset PWM signal is not zero, the temperature of the turn-off resistor of the IGBT is also related to the duty ratio of the second preset negative voltage and the value thereof.

If the duty ratio of the second preset negative voltage is equal to zero, as shown in fig. 4, in the case that it is determined that the system has a fault, the soft turn-off of the IGBT is performed first, then the driving voltage of the IGBT is maintained at the negative voltage for the first predetermined time T1, and then the driving voltage is pulled to the zero level and is maintained at the zero level state all the time. Experiments verify that the temperature of the IGBT turn-off resistance is maintained at about 43 ℃ by the protection method for maintaining the zero level of the driving voltage after the fault, and the temperature of the IGBT turn-off resistance is increased to 147 ℃ by the protection method for maintaining the negative voltage of the driving voltage after the fault in the prior art.

In the embodiment, the driving voltage of the IGBT can be kept at the preset PWM signal under the condition that the IGBT is completely turned off through the principle, so that the temperature rise of the IGBT turn-off resistance caused by the fact that the driving voltage of the IGBT is kept at the negative voltage for a long time is avoided, the safety risk, the heating failure and the fault spreading risk caused by the temperature rise of the IGBT turn-off resistance are further avoided, and the reliability of IGBT digital driving fault protection is improved; furthermore, the driving voltage of the IGBT is kept at the preset PWM signal, and the cost of the system is not increased.

Optionally, referring to fig. 5, in another embodiment of the present application, after the step S103 is executed to control the driving voltage of the IGBT to be the preset PWM signal, the method for protecting the IGBT driving protection circuit from faults further includes:

s201, judging whether the fault is eliminated.

The purpose of judging whether the fault is eliminated is to determine whether the wave can be sent to the IGBT normally, namely to determine whether the IGBT can enter a normal working state.

In conjunction with fig. 2 or fig. 4, whether the fault is eliminated can be determined by the change of the waveform of the fault signal, and the high level value in fig. 2 and fig. 4 indicates that the fault is eliminated, which is not limited in practical application. Specifically, in the IGBT driving protection circuit shown in fig. 6, the digital control unit 601 may directly determine whether the fault has been eliminated according to the fault signal output by the fault detection circuit 604; or, the digital control unit 601 may also perform the determination according to the condition of the fault return signal fed back by the upper computer 605, and if the fault return signal fed back by the upper computer indicates that the fault has been eliminated and the wave can be generated normally, the digital control unit 601 determines that the fault has been eliminated. If the fault is indeed cleared, step S202 is executed, where the rising edge of the fault signal in fig. 2 and 4 indicates the fault clearing position. In practice, the effective level of the fault signal may depend on the specific application environment, and is not limited to the form shown in fig. 2 and 4.

And S202, controlling the driving voltage of the IGBT to be kept at a third preset negative voltage within a second preset time.

Note that the end point of the second predetermined time is a start point of normal wave generation to the IGBT, and therefore the second predetermined time is a time period before normal wave generation to the IGBT. In fig. 2 or 4, the second predetermined time is indicated by an interval T2 between the sixth vertical dashed line and the seventh vertical dashed line.

The purpose of setting the driving voltage to be kept at the third preset negative voltage within the second preset time is to pull the driving voltage of the IGBT to the negative voltage again before the IGBT normally emits waves so as to ensure that the IGBT cannot be switched on by mistake when the IGBT normally emits waves.

The value of the second preset time can be determined according to the specific application environment, and the error conduction can be avoided only when normal wave sending is carried out on the IGBT.

The value of the third preset negative pressure can be the same as the value of the first preset negative pressure and/or the negative pressure in the prior art, and can be determined according to the specific application environment, and only by ensuring that the IGBT is not switched on by mistake when the IGBT emits light normally. The negative pressure in the prior art is preferred, and hardware improvement and cost increase are not needed.

Fig. 2 and 4 are taken as examples. And in the second preset time, the values of the third preset negative pressure and the first preset negative pressure are equal to the negative pressure in the prior art. In fig. 2, before the second predetermined time, the held predetermined PWM signal is a square wave, and the second predetermined negative voltage is also the same as the negative voltage in the prior art; in fig. 4, the held preset PWM signal is at a zero level until the second predetermined time.

And S203, normally emitting waves to the IGBT.

The purpose of normal wave generation to the IGBT is to control the IGBT to be in a normal operating state.

Similarly, referring to fig. 2 and 4, the driving voltage is positive in both figures to indicate normal wave generation. However, in practical applications, the driving voltage for driving the IGBT to normally generate the wave is not necessarily the positive voltage, and may be a voltage with other values.

In this embodiment, on the basis of avoiding heating failure and safety risk caused by temperature rise and further avoiding short circuit of a drive board power supply caused by heating failure, which further causes the further spread of the rising fault of the power supply circuit, before normal wave generation to the IGBT, the drive voltage of the IGBT is controlled to be kept at a third preset negative voltage within a second preset time, so that the misconduction of normal wave generation of the IGBT is avoided, and the accuracy of driving the IGBT is improved.

Optionally, in another embodiment of the present application, if the fault is eliminated, before the step S202 is executed to control the driving voltage of the IGBT to be maintained at the third preset negative voltage, the fault protection method for the IGBT driving protection circuit further includes:

The starting point of the third predetermined time is the first rising edge on the fault signal waveform, namely the fault elimination point, and the ending point of the third predetermined time is the starting point of the second predetermined time. In fig. 2 or 4, the third predetermined time is represented by an interval T3 between the fifth vertical dashed line and the sixth vertical dashed line; the time length depends on the specific application environment, and is within the protection scope of the present application.

It should be noted that the purpose of controlling the driving voltage of the IGBT to maintain the preset PWM signal until the third predetermined time is over is to keep the driving voltage of the IGBT in the off state as the preset PWM signal all the time, that is, before the IGBT recovers to normal wave generation, a period of blocking is set, and the driving voltage of the IGBT is maintained as the PWM signal, so as to reduce the risk of repeated start-up due to too short fault time.

Optionally, in another embodiment of the present application, before performing the timing processing and soft turn-off on the IGBT in step S101, the method for protecting the IGBT from the fault further includes:

The fault signal is from the fault detection circuit 604 in fig. 6, and the fault return signal is from the upper computer 605; the digital control unit 601 may directly determine whether the system has a fault according to the received fault signal, or may forward the fault signal to the upper computer 605, and the upper computer 605 completes the fault determination, and then determines whether the system has a fault according to the fault return signal. Depending on the specific application environment, are all within the scope of the present application.

It should be noted that, the step of determining whether the system has a fault according to the received fault signal or the fault return signal is performed to determine that the system has a fault, and then perform the timing processing and soft turn-off operations on the IGBT, so as to avoid the situation that the system has a misjudgment, and directly perform the timing processing and soft turn-off operations on the IGBT.

Optionally, referring to fig. 6, an embodiment of the present application further provides an IGBT driving protection circuit, including:

a digital control unit 601, a gate amplification circuit 602, a soft shutdown circuit 603, and a fault detection circuit 604. The digital control unit 601 is connected to the gate amplifier circuit 602, the soft shutdown circuit 603, and the fault detection circuit 604.

The fault detection circuit 604 is configured to detect a fault state of a system in which the IGBT is located, and generate and output a fault signal according to a detection result.

The gate amplifier circuit 602 is configured to amplify a normal driving signal of the IGBT according to the control of the digital control unit 601.

The soft shutdown circuit 603 is configured to implement soft shutdown of the IGBT according to control of the digital control unit 601.

The digital control unit 601 is used for executing the fault protection method of the IGBT driving protection circuit according to any of the embodiments described above.

The digital control unit 601 is also used for receiving a fault signal and judging whether the system has a fault or not or whether the fault is eliminated according to the fault signal. The fault signal is a signal generated by the fault detection circuit 604.

It should be noted that the digital control unit 601, the gate amplification circuit 602, and the soft shutdown circuit 603 are all disposed on the drive board of the IGBT.

It should be noted that the structures and principles of the gate amplifying circuit 602, the soft shutdown circuit 603, and the fault detecting circuit 604 are the same as those of the prior art, and thus are not described in detail.

In this embodiment, the digital control unit 601 cooperates with the gate amplification circuit 602, the soft shutdown circuit 603, and the fault detection circuit 604 to realize the drive protection of the IGBT. Specifically, the digital control unit 601 performs soft turn-off on the IGBT through the soft turn-off circuit 603 when it is determined that the system has a fault; then, within a first preset time, controlling the driving voltage of the IGBT to keep a first preset negative voltage, and ensuring that the IGBT is completely turned off; the driving voltage of the IGBT is controlled to be a preset PWM signal, the value of the preset PWM signal is zero level or second preset negative pressure, the second preset negative pressure is more than or equal to the first preset negative pressure, the duty ratio of the second preset negative pressure is more than or equal to zero, and the duty ratio of the zero level is more than zero, so that the temperature rise of the IGBT turn-off resistance caused by the fact that the driving voltage of the IGBT is kept at the negative pressure for a long time is avoided, the safety risk, the heating failure and the fault spreading risk caused by the temperature rise of the IGBT turn-off resistance are further avoided, and the reliability of IGBT digital driving fault protection is improved; moreover, the driving voltage of the IGBT is kept at the preset PWM signal, and the cost of the system is not required to be increased; furthermore, the digital control unit 601 can also store the control process, and can reserve field evidence for subsequent fault cause investigation.

Optionally, the IGBT driving circuit further includes:

and a blocking time setting unit 608 connected to the digital control unit 601 for setting the third predetermined time. Therein, the blocking time setting unit 608 may also be set to a key adjustment mode.

And a level mode setting unit 607 connected to the digital control unit 601 for setting a level mode of the IGBT. Therein, the level mode setting unit 607 may also be set to a key adjustment mode.

And a state display unit 606 connected to the digital control unit 601 for displaying the state of the digital control unit 601 and the operating state of the IGBT driving circuit.

It should be noted that, by additionally providing the blocking time setting unit 608 in the IGBT driving circuit, the time for the IGBT to enter blocking may be set, that is, the third predetermined time is set; and starting timing when the IGBT enters the blocking time, reaching the preset blocking time, and resetting the timing. The level mode setting unit 607 can be used to set the level signal received by the IGBT to be in a two-level mode or a multi-level mode, so that the digital control unit 601 performs the subsequent protection action.

Optionally, referring also to fig. 6, in another embodiment of the present application, the digital control unit 601 is further connected to an upper computer 605.

The digital control unit 601 is further configured to receive and generate a control input signal according to the fault signal, output the control input signal to the upper computer 605, and determine that a fault occurs in the system or the fault is eliminated after receiving a fault return signal fed back by the upper computer 605. Specifically, the digital control unit 601 receives a fault signal output by the fault detection circuit 604, and sends a control input signal to the upper computer 605 according to the fault signal; then, the upper computer 605 judges whether the system has a fault or whether the fault is eliminated according to the control input signal, and informs the digital control unit 601 of a corresponding judgment result in the form of a fault return signal; the digital control unit 601 performs further control operations based on the failure return signal.

It should be noted that, the digital control unit 601 is connected to the upper computer 605, and the protection of the IGBT driving protection circuit on the IGBT can be completed through the mutual cooperation between the upper computer 605 and the digital control unit 601, so that the human-computer interaction between the user and the IGBT driving protection circuit is more convenient.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fault protection method of an IGBT drive protection circuit is characterized by comprising the following steps:

controlling the driving voltage of the IGBT to be kept at a first preset negative pressure within a first preset time taking the ending point of the soft turn-off as a starting point, and ensuring that the IGBT is completely turned off;

controlling the driving voltage of the IGBT to be a preset PWM signal, and avoiding the temperature rise of a turn-off resistor of the IGBT caused by the fact that the driving voltage of the IGBT is kept at a negative voltage; the value of the preset PWM signal is zero level or second preset negative pressure, the second preset negative pressure is more than or equal to the first preset negative pressure, the duty ratio of the second preset negative pressure is more than or equal to zero, and the duty ratio of the zero level is more than zero.

2. The fault protection method of the IGBT drive protection circuit according to claim 1, wherein a duty ratio of the second preset negative voltage is equal to zero.

3. The fault protection method of the IGBT drive protection circuit according to claim 1, wherein the second preset negative voltage is equal to the first preset negative voltage.

4. The fault protection method of the IGBT drive protection circuit according to claim 1, further comprising, after controlling the drive voltage of the IGBT to a preset PWM signal:

judging whether the fault is eliminated;

and normally sending waves to the IGBT.

5. The fault protection method of the IGBT drive protection circuit according to claim 4, wherein if the fault is eliminated, before controlling the drive voltage of the IGBT to be maintained at a third preset negative voltage, the method further comprises:

6. The fault protection method of the IGBT drive protection circuit according to claim 4, wherein the third preset negative voltage is equal to the first preset negative voltage.

7. The fault protection method of the IGBT drive protection circuit according to any one of claims 1 to 6, wherein the soft turn-off is: a secondary shutdown, or a tertiary shutdown.

8. The fault protection method of the IGBT drive protection circuit according to any one of claims 1-6, characterized by, before the time sequence processing and soft turn-off of the IGBT, further comprising:

9. An IGBT drive protection circuit, comprising:

the digital control unit is used for executing the fault protection method of the IGBT drive protection circuit of any one of the claims 1-8.

10. The IGBT drive protection circuit of claim 9, wherein the digital control unit is further configured to receive the fault signal and determine whether a system has failed or whether the fault has been eliminated based on the fault signal.

11. The IGBT drive protection circuit of claim 9, wherein the digital control unit is further connected with an upper computer;

12. The IGBT drive protection circuit according to claim 9, further comprising:

13. The IGBT drive protection circuit according to claim 9, further comprising:

14. The IGBT drive protection circuit according to claim 9, further comprising:

and the state display unit is connected with the digital control unit and is used for displaying the state of the digital control unit and the working state of the IGBT driving protection circuit.