CN221408677U

CN221408677U - Switching tube driving device and electronic equipment

Info

Publication number: CN221408677U
Application number: CN202323542953.4U
Authority: CN
Inventors: 彭旭
Original assignee: Shenzhen Zhiding Driving Technology Co ltd
Current assignee: Shenzhen Zhiding Driving Technology Co ltd
Priority date: 2023-12-22
Filing date: 2023-12-22
Publication date: 2024-07-23
Anticipated expiration: 2033-12-22

Abstract

The application discloses a switching tube driving device and electronic equipment, and belongs to the technical field of variable frequency driving. The switching tube driving device is used for driving an outer tube and an inner tube which are positioned on the same side of the middle point of a bridge arm in an I-type three-level NPC topology, and comprises the following components: an outer tube driving module, an inner tube driving module and a logic management module; the outer tube driving module is connected with the outer tube driving signal and is connected with the outer tube, the inner tube driving module is connected with the inner tube driving signal and is connected with the inner tube, and the logic management module is respectively connected with the outer tube driving module and the inner tube driving module and is used for outputting a logic management signal determined according to a fault feedback signal output by the outer tube driving module; under the condition that the outer tube driving module detects that the outer tube enters a desaturation state, the outer tube driving module drives the outer tube to be turned off, the fault feedback signal is at a low level, and the logic management signal is at a low level, so that the outer tube driving module keeps driving the outer tube to be turned off, and the inner tube driving module delays driving the inner tube to be turned off according to the inner tube driving signal and the logic management signal at the low level.

Description

Switching tube driving device and electronic equipment

Technical Field

The embodiment of the application relates to the technical field of variable frequency driving, in particular to a switching tube driving device and electronic equipment.

Background

Currently, the market has increasingly larger requirements for miniaturization, high cost performance and single machine power of frequency converter products, and based on the consideration of three-level topology overall efficiency and power grid friendliness, an I-type three-level NPC (Neutral Point Clamped, neutral point clamp) topology constructed based on a switching tube gradually becomes a mainstream scheme. Compared with the two-level topology, the three-level topology has larger parasitic inductance parameters of the circuit loop, the current change is more complex, and particularly on high-power products, the larger power means larger current, so that higher voltage stress is caused, and when a bridge arm short circuit or an output short circuit fault occurs in the circuit, the voltage stress problem is particularly prominent, if the fault protection cannot be well performed, a switching tube in the I-type three-level NPC topology is easily damaged due to the voltage stress problem, so that the whole machine is exploded.

Aiming at the problems, the common short-circuit protection scheme in the related technology mainly comprises soft-off protection and active clamp protection, but the soft-off protection mode has the problem that the inner pipe is turned off before the outer pipe, so that the voltage of the whole bus is superposed on the inner pipe; the active clamp protection mode is complex in circuit and high in debugging difficulty, and the risk that the upper bridge arm and the lower bridge arm are short-circuited due to misleading of a switching tube so as to cause a frying machine exists.

Disclosure of utility model

The embodiment of the application mainly aims to provide a switching tube driving device and electronic equipment, and aims to realize that an outer tube of a bridge arm switching tube is turned off before an inner tube by a simple and easy-to-debug circuit and solve the problem of voltage stress when an I-type three-level NPC topology is short-circuited.

In order to achieve the above object, an embodiment of the present application provides a switching tube driving device for driving an outer tube and an inner tube located on the same side of a bridge arm midpoint in an I-type three-level NPC topology, the switching tube driving device including: an outer tube driving module, an inner tube driving module and a logic management module;

The first input end of the outer tube driving module is connected with an outer tube driving signal, the voltage detection end and the output end of the outer tube driving module are connected with the outer tube, the first input end of the inner tube driving module is connected with the inner tube driving signal, the output end of the inner tube driving module is connected with the inner tube, the input end of the logic management module is connected with the feedback end of the outer tube driving module, and the output end of the logic management module is respectively connected with the second input end of the outer tube driving module and the second input end of the inner tube driving module;

The logic management module is used for outputting logic management signals to the outer pipe driving module and the inner pipe driving module, wherein the logic management signals are determined according to fault feedback signals output by the outer pipe driving module;

The outer tube driving module is used for driving the outer tube to be turned on or turned off according to the outer tube driving signal and the logic management signal, and outputting the fault feedback signal to the logic management module according to the working state of the outer tube;

The inner pipe driving module is used for driving the inner pipe to be turned on or turned off according to the inner pipe driving signal and the logic management signal, wherein the time of the inner pipe to be turned off is later than the time of the outer pipe to be turned off;

And under the condition that the outer tube driving module detects that the outer tube enters a desaturation state, the outer tube driving module drives the outer tube to be turned off, the fault feedback signal is of a low level, the logic management signal is of a low level, and the inner tube driving module drives the inner tube to be turned off in a delayed mode according to the inner tube driving signal and the logic management signal of the low level.

Optionally, the outer tube driving module includes: the first isolation unit, the first driving optocoupler and the voltage detection unit;

The first input end of the first isolation unit is the first input end of the outer tube driving module, the second input end of the first isolation unit is the second input end of the outer tube driving module, the output end of the first isolation unit is connected with the anode of the first driving optocoupler, and the first isolation unit is used for outputting a first level signal to the first driving optocoupler according to the outer tube driving signal and the logic management signal;

The output end of the voltage detection unit is connected with the voltage detection end of the first driving optocoupler, the first sampling end and the second sampling end of the voltage detection unit are used as the voltage detection end of the outer tube driving module and are respectively connected with the first end and the second end of the outer tube, and the voltage detection unit is used for detecting the voltage between the first end and the second end of the outer tube;

The output end of the first driving optocoupler is connected with the controlled end of the outer tube, and the first driving optocoupler is used for driving the outer tube to be turned on or turned off according to the first level signal and the output signal of the voltage detection unit, and outputting the fault feedback signal to the logic management module according to the output signal of the voltage detection unit.

Optionally, the first isolation unit includes: the first buffer, the first AND gate, the first resistor and the second buffer;

The input end of the first buffer is the first input end of the first isolation unit, the output end of the first buffer is connected with the first input end of the first AND gate, the second input end of the first AND gate is the second input end of the first isolation unit, the output end of the first AND gate is connected with one end of the first resistor, the other end of the first resistor is connected with the input end of the second buffer, and the output end of the second buffer is the output end of the first isolation unit.

Optionally, the voltage detection unit includes: the second resistor, the third resistor, the fourth resistor, the first capacitor and the comparison diode;

One end of the second resistor is connected with a first positive voltage, the other end of the second resistor is connected with one end of the third resistor and the anode of the comparison diode, the other end of the third resistor, one end of the fourth resistor and one end of the first capacitor are used as the output end of the voltage detection unit together, the cathode of the comparison diode is a first sampling end of the voltage detection unit, and the other end of the fourth resistor and the other end of the first capacitor are second sampling ends of the voltage detection unit;

An output signal of the voltage detection unit is determined according to the first positive electrode voltage and the voltage between the first end and the second end of the outer tube.

Optionally, the inner tube driving module includes: the second isolation unit and the second driving optocoupler;

The first input end of the second isolation unit is the first input end of the inner pipe driving module, the second input end of the second isolation unit is the second input end of the inner pipe driving module, the output end of the second isolation unit is connected with the anode of the second driving optocoupler, and the second isolation unit is used for outputting a second level signal to the second driving optocoupler in a delayed manner according to the inner pipe driving signal and the logic management signal;

The output end of the second driving optocoupler is connected with the controlled end of the inner tube, the negative electrode power supply end of the second driving optocoupler is connected with the second end of the inner tube, and the second driving optocoupler is used for driving the inner tube to be turned on or turned off later than the outer tube according to the second level signal.

Optionally, the second isolation unit includes: the third buffer, the second AND gate, the delay circuit and the fourth buffer;

The input end of the third buffer is the first input end of the second isolation unit, the output end of the third buffer is connected with the first input end of the second AND gate, the second input end of the second AND gate is the second input end of the second isolation unit, the output end of the second AND gate is connected with one end of the delay circuit, the other end of the delay circuit is connected with the input end of the fourth buffer, and the output end of the fourth buffer is the output end of the second isolation unit.

Optionally, the delay circuit includes: a fifth resistor and a second capacitor;

One end of the fifth resistor is connected with the output end of the second AND gate, the other end of the fifth resistor is connected with one end of the second capacitor and the input end of the fourth buffer, and the other end of the second capacitor is grounded.

Optionally, the logic management module includes: a sixth resistor, a third capacitor and a fifth buffer;

One end of the sixth resistor is connected with working voltage, the other end of the sixth resistor, one end of the third capacitor and the input end of the fifth buffer are connected with the feedback end of the outer tube driving module, the other end of the third capacitor is grounded, and the output end of the fifth buffer is the output end of the logic management module.

Optionally, the switching tube driving device further includes: a fault feedback module;

The fault feedback module is connected with the feedback end of the outer tube driving module and is used for feeding back the working state of the outer tube to external equipment.

In addition, in order to achieve the above purpose, the embodiment of the application also provides an electronic device, which comprises the switching tube driving device.

The embodiment of the application provides a switching tube driving device and electronic equipment, which overcome the problem of X in the related technology. The switching tube driving device is used for driving an outer tube and an inner tube which are positioned on the same side of the middle point of a bridge arm in an I-type three-level NPC topology, and comprises the following components: an outer tube driving module, an inner tube driving module and a logic management module; the first input end of the outer tube driving module is connected with an outer tube driving signal, the voltage detection end and the output end of the outer tube driving module are connected with the outer tube, the first input end of the inner tube driving module is connected with an inner tube driving signal, the output end of the inner tube driving module is connected with the inner tube, the input end of the logic management module is connected with the feedback end of the outer tube driving module, and the output end of the logic management module is respectively connected with the second input end of the outer tube driving module and the second input end of the inner tube driving module; the logic management module is used for outputting logic management signals to the outer pipe driving module and the inner pipe driving module, wherein the logic management signals are determined according to fault feedback signals output by the outer pipe driving module; the outer tube driving module is used for driving the outer tube to be turned on or turned off according to the outer tube driving signal and the logic management signal, and outputting a fault feedback signal to the logic management module according to the working state of the outer tube; the inner pipe driving module is used for driving the inner pipe to be turned on or turned off according to the inner pipe driving signal and the logic management signal, wherein the time of the inner pipe to be turned off is later than the time of the outer pipe to be turned off; under the condition that the outer tube driving module detects that the outer tube enters a desaturation state, the outer tube driving module drives the outer tube to be turned off, the fault feedback signal is of a low level, the logic management signal is of a low level, and the inner tube driving module drives the inner tube to be turned off later than the outer tube.

The embodiment of the application is based on a reasonable loop current conversion principle, and an outer tube driving module with the function of detecting whether the outer tube enters a desaturation state is designed in the switching tube driving device, so that the outer tube can be turned off in time under the condition that a short circuit abnormality occurs in a three-level topology, and the problem of voltage stress occurring during the short circuit of the three-level topology is solved; meanwhile, the outer tube driving module can also change the switching tube driving logic of the outer tube driving module and the inner tube driving module within a certain time after the outer tube is turned off through the fault feedback signal and the logic management module, and finally the outer tube turn-off interlocking function is realized; in addition, the inner tube driving module is designed not to detect the working state of the inner tube, and short delay is arranged in the inner tube driving module, so that the inner tube can be ensured to be delayed to be turned off after the outer tube is turned off when the short circuit problem occurs, and the problem that the whole bus voltage is superposed on the inner tube before the outer tube is turned off can be effectively avoided.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the related art, the drawings that are required to be used in the embodiments or the related technical descriptions will be briefly described, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained from the structures shown in the drawings without inventive effort for those skilled in the art.

Fig. 1 is a schematic structural diagram of a switching tube driving device according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a three-level NPC topology of type I in the related art;

Fig. 3 is a schematic diagram of a refinement structure of a switching tube driving device according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of a switching tube driving device according to another embodiment of the present application;

Fig. 5 is a schematic diagram of a refinement structure of a switching tube driving device according to another embodiment of the present application;

fig. 6 is a schematic diagram of an operating principle of a switching tube driving device according to an embodiment of the present application;

Fig. 7 is a schematic diagram of another working principle of the switching tube driving device according to the embodiment of the present application;

FIG. 8 is a schematic diagram of a three-level topology of a switching tube driving device for driving control according to an embodiment of the present application;

Fig. 9 is a schematic diagram of another loop commutation path of a three-level topology before and after driving control by a switching tube driving device according to an embodiment of the present application.

The achievement of the objects, functional features and advantages of the embodiments of the present application will be further described with reference to the drawings in conjunction with the embodiments.

Reference numerals illustrate:

Reference numerals	Name of the name	Reference numerals	Name of the name
				100	Outer tube driving module	PWM_m	Outer tube drive signal
200	Inner tube driving module	PWM_n	Inner tube driving signal
				300	Logic management module	G1～G6	First to sixth buffers
101	First isolation unit	Y1～Y2	First to second AND gates
				Um	First driving optocoupler	R1～R6	First to sixth resistors
102	Voltage detection unit	C1～C3	First to second capacitors
				201	Second isolation unit	D7	Comparison diode
Un	Second driving optocoupler	VDD	Supply voltage
				ANODE	Anode for driving optocoupler	CATHODE	Cathode for driving optocoupler
FAULT	Feedback end	DESAT	Voltage detection terminal
				GND	Ground terminal/ground wire	VOUT	Output end of driving optocoupler
VCC	Positive electrode power supply terminal	VE/VEE	Negative electrode power supply terminal
				VCC_m	First positive electrode voltage	VEE_m	First negative electrode voltage
VCC_n	Second positive electrode voltage	VEE_n	Second negative electrode voltage
				Cm	Collector of outer tube	Cn	Collector of inner tube
Gm	Gate of outer tube	400	Fault feedback module
				Em	Emitter of outer tube	En	Emitter of inner tube

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments of the present application without making any inventive effort, are intended to be within the scope of the embodiments of the present application.

It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present application are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.

In addition, descriptions such as those related to "first," "second," and the like in embodiments of the present application are for descriptive purposes only and are not to be construed as indicating or implying a relative importance or an implicit indication of the number of features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the embodiments of the present application, the meaning of "plurality" is at least two, for example, two, three, etc., unless explicitly defined otherwise. In addition, the meaning of "and/or" as it appears throughout is meant to include three side-by-side schemes, for example, "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B meet at the same time.

In embodiments of the present application, unless explicitly specified and limited otherwise, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be either a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to specific circumstances.

It should also be appreciated that references to "one embodiment" or "some embodiments" or the like described in the specification of an embodiment of the present application mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more, but not all, embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

In the current industrial applications such as coal mines, metallurgy and the like, the market has increasingly larger requirements on frequency converter products, the cost performance is high, and the frequency converter with the medium-voltage 1140V three-level topology based on a withstand voltage 1700V IGBT (Insulate-Gate Bipolar Transistor, insulated gate bipolar transistor) module gradually becomes a mainstream scheme based on the consideration of three-level topology overall efficiency and power grid friendliness. However, the higher power density and the higher single power face a troublesome problem in the development process, compared with the two-level topology, the parasitic inductance parameter of the three-level topology circuit loop is larger, the current exchange path is more complex, and particularly on a high-power product, the higher power means larger current, so that higher voltage stress is caused, and when a bridge arm short circuit or an output short circuit fault occurs in the circuit, the problem is particularly prominent, if the fault protection cannot be made, the IGBT is easy to damage due to the voltage stress problem, and the whole machine is exploded.

In view of the above problems, the short-circuit protection schemes commonly used in the related art mainly include the following two types:

1) The IGBT soft turn-off protection mode has application defects in a medium-voltage 1140V three-level NPC I type topological frequency converter based on 1700V IGBT modules: if the frequency converter is a low-power frequency converter with the power of 400kW or below, when a bridge arm short circuit or an output short circuit occurs, the soft turn-off function can protect the IGBT from being damaged by voltage stress due to small current, small power loop and small stray inductance of the loop; however, if the power of the frequency converter is larger, for example, more than 630kW or even MW, the current is large, the power loop is correspondingly increased, and the loop stray inductance is correspondingly increased, so that the inner tube is turned off before the outer tube under the condition of bridge arm short circuit or output short circuit, the whole bus voltage is further superimposed on the inner tube, the peak voltage of the loop stray inductance is superimposed, the IGBT inner tube is easily broken down by voltage stress, and in severe cases, half bridge arms or even the whole bridge arm are further broken down. Therefore, the soft turn-off protection mode is limited in application in medium-voltage 1140V three-level NPC I type topological scenes with medium and high power based on 1700V IGBT modules.

2) The active clamp protection mode utilizes a TVS (TRANSIENT VOLTAGE SUPPRESSOR, transient voltage suppression tube) and a common fast recovery diode to be connected between the C pole and the G pole of the IGBT in a bridging way, when a bridge arm short circuit occurs in a loop or the output short circuit occurs in the loop, the VCE voltage of the IGBT can rise to exceed the breakdown voltage of the TVS, the TVS is broken down, current flows into the G pole of the IGBT, the voltage between G, E poles is raised, and the VCE voltage is indirectly clamped at a proper voltage value, so that the current change rate dic/dt of the current flowing through the pole C, E at the turn-off moment of the IGBT is reduced, and the damage to the IGBT caused by too high peak voltage of the turn-off VCE is avoided. However, the protection mode has the defects of complex circuit, wide breakdown voltage range, large loss, large error of positive temperature characteristic of the TVS, and the like, the characteristics of the TVS tube are that after breakdown, breakdown current is increased sharply, the breakdown voltage working point of the TVS tube is increased sharply correspondingly, so that the VCE voltage of the IGBT is increased correspondingly, and the VCE voltage clamping effect is poor, therefore, the protection mode has high requirements on TVS performance and PCB layout wiring loops and is difficult to debug, particularly in four-quadrant application with high bus voltage, an active clamping circuit TVS with an upper bridge arm being opened and a lower bridge arm being closed is broken down, breakdown current flows to a gate electrode, the gate electrode voltage is raised, the IGBT is turned on by mistake, and finally the upper bridge arm and the lower bridge arm are short-circuited, so that the situation of a frying machine is caused.

Based on the problem, when the middle-voltage 1140V three-level NPC I type topology based on 1700V IGBT module with middle and high power has short circuit fault, the IGBT is damaged due to VCE voltage stress, the embodiment of the application provides a switching tube driving device and electronic equipment, and an active clamping circuit is not required to be additionally added, so that the complexity and the debugging difficulty of a circuit are reduced. Compared with an IGBT soft turn-off protection mode, the switch tube driving device avoids the condition that the inner tube is turned off before the outer tube, and solves the problem of limited application of 1700V IGBT modules in a medium-high power medium-voltage 1140V three-level NPC I type topological scene; compared with an active clamp protection mode, the fault feedback and logic management part in the switching tube driving device is simpler than an active clamp circuit, is easy to debug and realize, and can avoid the risk of error conduction of the IGBT in the active clamp circuit.

The embodiment of the application provides a switching tube driving device and an electronic device, and the switching tube driving device and the electronic device are specifically described through the following embodiments.

The embodiment of the application provides a switching tube driving device, referring to fig. 1, fig. 1 is a schematic structural diagram of the switching tube driving device provided by the embodiment of the application, where the switching tube driving device is used for driving an outer tube and an inner tube located at the same side of a middle point of a bridge arm in an I-type three-level NPC topology, and the switching tube driving device comprises: an outer tube driving module 100, an inner tube driving module 200, and a logic management module 300;

The first input end of the outer tube driving module 100 is connected with an outer tube driving signal PWM_m, the voltage detection end and the output end of the outer tube driving module 100 are connected with the outer tube, the first input end of the inner tube driving module 200 is connected with an inner tube driving signal PWM_n, the output end of the inner tube driving module 200 is connected with the inner tube, the input end of the logic management module 300 is connected with the feedback end of the outer tube driving module 100, and the output end of the logic management module 300 is respectively connected with the second input end of the outer tube driving module 100 and the second input end of the inner tube driving module 200;

The logic management module 300 is configured to output logic management signals to the outer pipe driving module 100 and the inner pipe driving module 200, where the logic management signals are determined according to a fault feedback signal output by the outer pipe driving module 100;

The outer pipe driving module 100 is configured to drive the outer pipe to be turned on or off according to the outer pipe driving signal pwm_m and the logic management signal, and further configured to output a fault feedback signal to the logic management module 300 according to the working state of the outer pipe;

the inner tube driving module 200 is configured to drive the inner tube to be turned on or off according to the inner tube driving signal pwm_n and the logic management signal, where the time of the inner tube to be turned off is later than the time of the outer tube to be turned off;

Under the condition that the outer tube driving module 100 detects that the outer tube enters the desaturation state, the outer tube driving module 100 drives the outer tube to be turned off, the fault feedback signal is low level, the logic management signal is low level, and the inner tube driving module 200 drives the inner tube to be turned off in a time delay mode according to the inner tube driving signal and the logic management signal of the low level.

In this embodiment, the outer tube and the inner tube may be IGBTs or the like, or may be other switching tubes with similar functions, such as transistors, MOS tubes, or the like, which is not limited in this embodiment; the type I three-level NPC topology involved in the embodiment may be a medium voltage 1140V three-level topology constructed based on a withstand voltage 1700V IGBT module, but it is not represented that the switching tube driving device provided in the embodiment can only be used for driving an outer tube and an inner tube on the same side as the midpoint of the bridge arm in the specified three-level topology in the application scenario, and it is not represented that the switching tube driving device can only be used for driving an IGBT.

The schematic structural diagram of the I-type three-level NPC topology according to this embodiment may refer to fig. 2, where S1 to S4 are IGBT switching tubes, D1 to D4 are IGBT body diodes, D5 to D6 are freewheel diodes, and Cb1 to Cb2 are upper and lower bus capacitors; s1, S2, D1, D2 and D5 form an upper bridge arm, S3, S4, D3, D4 and D6 form a lower bridge arm, S1 and S4 are outer pipes, and S2 and S3 are inner pipes; ux is output, DC+ and DC-are positive and negative voltages of the rectified direct current bus, and O is a bus voltage midpoint; the three groups of bridge arms are connected in parallel to form a three-phase inverter circuit.

As can be seen from fig. 2, in the I-type three-level NPC topology, S1 and S2 are a group of outer tubes and inner tubes located on the same side of the midpoint of the bridge arm, S4 and S3 are another group of outer tubes and inner tubes located on the same side of the midpoint of the bridge arm, and the switching tube driving device provided in this embodiment may be used to drive S1 and S2, or may also be used to drive S4 and S3, so in order to provide more reliable short-circuit protection, it is obvious that the two groups of outer tubes and inner tubes on both sides of the midpoint of the bridge arm need to be driven and controlled by the switching tube driving device, so that the three-level topology may be short-circuited by setting two groups of switching tube driving devices, and the two groups of switching tube driving devices may be set independently of each other, or may be integrated into a new switching tube driving device and then connected to the three-level topology, or may be set by other equivalent means, which may not be limited by this embodiment.

In this embodiment, the working state of the outer tube is detected by the outer tube driving module 100 to determine whether a short circuit abnormality occurs in the three-level topology, and if no short circuit abnormality occurs in the three-level topology, the fault feedback signal output by the outer tube driving module 100 is at a high level, and the logic management signal output by the logic management module 300 is also at a high level, at this time, the outer tube driving module 100 and the inner tube driving module 200 drive the outer tube and the inner tube to be turned on or off according to the level signals provided by the outer tube driving signal pwm_m and the inner tube driving signal pwm_n, respectively; under the condition that the three-level topology is abnormal, the outer tube driving module 100 stops outputting the level signal to the outer tube, which is equivalent to driving the outer tube to turn off, meanwhile, the fault feedback signal output by the outer tube driving module 100 is low level, the logic management signal output by the logic management module 300 is also low level, at this time, the outer tube driving module 100 and the inner tube driving module 200 both drive the outer tube and the inner tube to turn off based on the logic management signal of the low level, because the working state abnormality of the outer tube is detected by the outer tube driving module 100 and the action of turning off the outer tube is made, the inner tube turning off of the inner tube driving module 200 needs to be realized after knowing that the logic management signal determined by the logic management module 300 based on the fault feedback signal becomes low level, therefore, the time of controlling the outer tube to turn off can be delayed, in addition, in order to adapt to the switching tubes of different power levels, the adjustable delay time can be added for the inner tube driving module 200, and the short circuit protection effect of more fitting the actual application requirements can be achieved.

The embodiment provides a switching tube driving device, which does not need to additionally increase an active clamping circuit, thereby reducing the complexity and debugging difficulty of a circuit, changing the logic and time delay for driving a switching tube based on a reasonable loop commutation principle, specifically, designing an outer tube driving module with the function of detecting whether an outer tube enters a desaturation state or not in the switching tube driving device, so that the outer tube can be turned off in time under the condition of short circuit abnormality in three-level topology, and solving the problem of voltage stress generated when the three-level topology is short-circuited; meanwhile, the outer tube driving module can also change the switching tube driving logic of the outer tube driving module and the inner tube driving module within a certain time after the outer tube is turned off through the fault feedback signal and the logic management module, and finally the outer tube turn-off interlocking function is realized; in addition, the inner tube driving module is designed not to detect the working state of the inner tube, and short delay is arranged in the inner tube driving module, so that the inner tube can be ensured to be delayed to be turned off after the outer tube is turned off when the short circuit problem occurs, and the problem that the voltage stress of the whole bus is superposed on the inner tube due to the fact that the inner tube is turned off before the outer tube is effectively avoided.

Referring to fig. 3, in some possible embodiments, the outer tube driving module 100 may include: the first isolation unit 101, the first driving optocoupler Um and the voltage detection unit 102;

The first input end of the first isolation unit 101 is a first input end of the outer tube driving module 100, the second input end of the first isolation unit 101 is a second input end of the outer tube driving module 100, the output end of the first isolation unit 101 is connected with an ANODE of the first driving optocoupler Um, and the first isolation unit 101 is used for outputting a first level signal to the first driving optocoupler Um according to the outer tube driving signal pwm_m and the logic management signal;

The first end of the voltage detection unit 102 is connected with a first positive voltage VCC_m, the output end of the voltage detection unit 102 is connected with a voltage detection end DESAT of the first driving optocoupler Um, a first sampling end and a second sampling end of the voltage detection unit 102 are used as voltage detection ends of the outer tube driving module 100, the first sampling end of the voltage detection unit 102 is connected with a collector Cm of the outer tube, the second sampling end of the voltage detection unit 102 is connected with a negative power supply end VEE of the first driving optocoupler Um and an emitter Em of the outer tube, and the first negative voltage VEE_m is connected with the second sampling end of the voltage detection unit 102 for detecting a collector-emitter voltage VCE of the outer tube;

The positive electrode power supply end VCC of the first driving optocoupler Um is connected to a first positive electrode voltage VCC_m, the feedback end FAULT of the first driving optocoupler Um is a feedback end of the outer tube driving module 100, the CATHODE CATHODE and the ground wire end GND of the first driving optocoupler Um are grounded, the output end VOUT of the first driving optocoupler Um is connected with the gate Gm of the outer tube, the first driving optocoupler Um is used for driving the outer tube to be turned on or off according to a first level signal and an output signal of the voltage detection unit 102, and outputting a FAULT feedback signal to the logic management module 300 according to the output signal of the voltage detection unit 102.

In the present embodiment, the first isolation unit 101 mainly plays a role of signal buffering and performing and logic processing on the external pipe driving signal pwm_m and the logic management signal. The signal buffering can avoid interference of environmental factors on signals, so that the output end is in-phase (or at the same level) with the input end, but the output end has much stronger carrying capacity than the input end; by AND logic processing, the first level signal and the outer tube driving signal PWM_m can keep consistent in level under the condition that the logic management signal is at a high level; when the logic management signal is at a low level, the first level signal and the logic management signal are kept at the same level.

In this embodiment, as an example, the first end and the second end of the outer tube are the collector Cm and the emitter Em, respectively, and the voltage detecting unit 102 is configured to detect the voltage drop between the collector-emitter voltage VCE of the outer tube, that is, C, E of the outer tube, and compare the voltage drop with the first positive voltage vcc_m, where the voltage comparison result of the two voltages affects the voltage of the voltage detecting end DESAT of the first driving optocoupler Um.

In this embodiment, as an example, the controlled end of the outer tube is the gate Gm, the first driving optocoupler Um is also connected to the power supply voltage VDD, the first driving optocoupler Um is an isolated driving optocoupler with a DESAT voltage detection function, after receiving the output signal of the voltage detection unit 102 through the voltage detection end DESAT, the first driving optocoupler Um needs to compare the output signal with the comparator reference voltage inside Um, so as to determine the level of the FAULT feedback signal, while the output signal of the voltage detection unit 102 relates to the voltage comparison result of VCE and the first positive voltage vcc_m, and when VCE is lower than the first positive voltage vcc_m, the voltage introduced into the driving optocoupler DESAT pin (i.e. the output signal of the voltage detection unit 102) is lower than the comparator reference voltage inside Um, the FAULT feedback signal output from the FAULT end after the inversion processing is continuously kept at the high level, so that the logic management signal is also continuously kept at the high level, and at this time, the outer tube normally is driven based on the outer tube driving signal pwm_m; under the condition that VCE is far higher than the first positive voltage vcc_m, the voltage (i.e., the output signal of the voltage detection unit 102) introduced into the driving optocoupler DESAT pin gradually rises until exceeding the comparator reference voltage inside Um, at this time Um turns off the VOUT output driving signal to the outer tube, and meanwhile, the FAULT feedback signal output from the FAULT terminal after the inversion processing becomes low level, so that the logic management signal also becomes low level, so that the first level signal in a certain subsequent time is low level, and the outer tube remains in the off state in this period.

As an example, the first isolation unit 101 may include: the first buffer G1, the first AND gate Y1, the first resistor R1 and the second buffer G2;

The input end of the first buffer G1 is the first input end of the first isolation unit 101, the output end of the first buffer G1 is connected with the first input end of the first AND gate Y1, the second input end of the first AND gate Y1 is the second input end of the first isolation unit 101, the output end of the first AND gate Y1 is connected with one end of the first resistor R1, the other end of the first resistor R1 is connected with the input end of the second buffer G2, and the output end of the second buffer G2 is the output end of the first isolation unit 101.

In this embodiment, the input end of the first buffer G1 is connected to the outer tube driving signal pwm_m, the output end of the first buffer G1 is connected to the first input end of the first and gate Y1, the second input end of the first and gate Y1 is connected to the logic management signal from the logic management module 300, the output end of the first and gate Y1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the input end of the second buffer G2, the output end of the second buffer G2 is connected to the anode of the first driving optocoupler Um, and the signal generated after the and logic processing of the first and gate Y1 is the first level signal input to the anode of the first driving optocoupler Um after passing through the first resistor R1 and the second buffer G2 based on the outer tube driving signal pwm_m and the logic management signal.

As an example, the voltage detection unit 102 may include: the second resistor R2, the third resistor R3, the fourth resistor R4, the first capacitor C1 and the comparison diode D7;

One end of the second resistor R2 is a first end of the voltage detection unit 102, the other end of the second resistor R2 is connected with one end of the third resistor R3 and an anode of the comparison diode D7, the other end of the third resistor R3, one end of the fourth resistor R4 and one end of the first capacitor C1 are jointly used as output ends of the voltage detection unit 102, a cathode of the comparison diode D7 is a first sampling end of the voltage detection unit 102, and the other end of the fourth resistor R4 and the other end of the first capacitor C1 are second sampling ends of the voltage detection unit 102;

Under the condition that the emitter collecting voltage VCE of the outer tube is larger than the first positive electrode voltage VCC_m, the comparison diode D7 is cut off, the first positive electrode voltage VCC_m charges the first capacitor C1 through the second resistor R2 and the third resistor R3, the voltage of the voltage detection end DESAT of the first driving optocoupler Um is increased, and when the voltage of the voltage detection end DESAT of the first driving optocoupler Um is larger than the internal comparison voltage of the first driving optocoupler Um, the outer tube is regarded as a desaturation state, and the first driving optocoupler Um drives the outer tube to be cut off.

In this embodiment, one end of the second resistor R2 is connected to the first positive voltage vcc_m, which corresponds to the voltage of the anode of the comparator diode D7 being vcc_m, the cathode of the comparator diode D7 being connected to the collector Cm of the outer tube, which corresponds to the voltage of the cathode of the comparator diode D7 being VCE, under the condition that the three-level topology works normally, the voltage drop between the outer tube C, E is about 2V, which is smaller than the first positive voltage vcc_m, at this time D7 is turned on, the voltage drop is about 1V, and the vce+vd7 voltage is divided by the third resistor R3 and the fourth resistor R4 and is introduced into the DESAT pin of the first driving optocoupler Um, but the voltage is lower than the reference voltage of the comparator inside Um, so that the first driving optocoupler Um normally transmits the driving signal to the outer tube; under the condition that short circuit abnormality occurs in the three-level topology, VCE is far higher than VCC_m, at the moment, D7 is cut off, the first positive voltage VCC_m charges the first capacitor C1 through the second resistor R2 and the third resistor R3, the voltage of the voltage detection end DESAT of the first driving optocoupler Um is increased, when the voltage of the voltage detection end of the first driving optocoupler Um is larger than the internal comparison voltage of the first driving optocoupler Um, the outer tube is regarded as being in a desaturation state, and the first driving optocoupler Um drives the outer tube to be cut off.

Referring to fig. 3, in some possible embodiments, the inner tube driving module 200 may include: a second isolation unit 201 and a second driving optocoupler Un;

The first input end of the second isolation unit 201 is the first input end of the inner tube driving module 200, the second input end of the second isolation unit 201 is the second input end of the inner tube driving module 200, the output end of the second isolation unit 201 is connected with the ANODE mode of the second driving optocoupler Un, and the second isolation unit 201 is used for outputting a second level signal to the second driving optocoupler Un in a delayed manner according to the inner tube driving signal pwm_n and the logic management signal;

The positive electrode power supply end VCC of the second driving optocoupler Un is connected to a second positive electrode voltage VCC_n, the negative electrode CATHODE of the second driving optocoupler Un and the ground wire end GND are grounded, the output end VOUT of the second driving optocoupler Un is connected with the gate electrode Gn of the inner tube, the negative electrode power supply end VEE of the second driving optocoupler Un is connected with the emitter En of the inner tube and is connected to a second negative electrode voltage VEE_n, and the second driving optocoupler Un is used for driving the inner tube to be turned on or off later than the outer tube according to a second level signal.

In this embodiment, the second isolation unit 201 mainly performs signal buffering, and logic processing on the inner tube driving signal pwm_n and the logic management signal, and delay output. The signal buffering can avoid interference of environmental factors on signals, so that the output end is in-phase (or at the same level) with the input end, but the output end has much stronger carrying capacity than the input end; by AND logic processing, the second level signal and the inner tube driving signal PWM_n can keep consistent in level under the condition that the logic management signal is at a high level; when the logic management signal is at a low level, the second level signal is consistent with the level of the logic management signal; through the time delay output, the time delay turn-off of the inner tube after the outer tube is turned off can be guaranteed when the short circuit problem occurs in the three-level topology, and the problem of voltage stress of the whole bus voltage superimposed on the inner tube caused by the fact that the inner tube is turned off before the outer tube can be effectively avoided.

In this embodiment, as an example, the controlled end of the inner tube is the gate Gn, the second end of the inner tube is the emitter En, and the second driving optocoupler Um is further connected to the power supply voltage VDD, unlike the first driving optocoupler Um, the second driving optocoupler Un is an isolated driving optocoupler without the DESAT voltage detection function, so that the second driving optocoupler Un does not turn off the inner tube by itself, but only decides how to drive and control the inner tube according to the second level signal from the second isolation unit 201.

As an example, the second isolation unit 201 may include: a third buffer G3, a second AND gate Y2, a delay circuit and a fourth buffer G4;

The input end of the third buffer G3 is the first input end of the second isolation unit 201, the output end of the third buffer G3 is connected with the first input end of the second and gate Y2, the second input end of the second and gate Y2 is the second input end of the second isolation unit 201, the output end of the second and gate Y2 is connected with one end of the delay circuit, the other end of the delay circuit is connected with the input end of the fourth buffer G4, and the output end of the fourth buffer G4 is the output end of the second isolation unit 201.

As an example, the delay circuit may include: a fifth resistor R5 and a second capacitor C2;

One end of the fifth resistor R5 is connected with the output end of the second AND gate Y2, the other end of the fifth resistor R5 is connected with one end of the second capacitor C2 and the input end of the fourth buffer G4, and the other end of the second capacitor C2 is grounded.

In this embodiment, the input end of the third buffer G3 is connected to the inner tube driving signal pwm_n, the output end of the third buffer G3 is connected to the first input end of the second and gate Y2, the second input end of the second and gate Y2 is connected to the logic management signal from the logic management module 300, the output end of the second and gate Y2 is connected to one end of the fifth resistor R5, the other end of the fifth resistor R5 is connected to one end of the second capacitor C2 and the input end of the fourth buffer G4, the output end of the fourth buffer G4 is connected to the anode of the second driving optocoupler Un, the signal generated after the and logic processing is performed by the second and gate Y1 based on the inner tube driving signal pwm_n and the logic management signal is subjected to delay processing by the fifth resistor R5 and the second capacitor C2, and then the signal is the second level signal input to the anode of the second driving optocoupler Un after passing through the second buffer G2.

It should be noted that the RC delay circuit provided in this embodiment is only an example of a simple delay circuit that is easy to implement, and other circuits that can implement the delay function may be adopted to flexibly replace the RC delay circuit, and the schemes of these simple alternative delay circuits should all belong to the protection scope of this embodiment.

Referring to fig. 3, in some possible embodiments, the logic management module 300 may include: a sixth resistor R6, a third capacitor C3 and a fifth buffer G5;

One end of the sixth resistor R6 is connected to the working voltage, the other end of the sixth resistor R6, one end of the third capacitor C3 and the input end of the fifth buffer G5 are connected to the feedback end of the outer tube driving module 100, the other end of the third capacitor C3 is grounded, and the output end of the fifth buffer G5 is the output end of the logic management module 300.

In this embodiment, the working voltage may be the power supply voltage VDD of the first driving optocoupler Um, or may be provided by another power supply, and the sixth resistor R6 with one end connected to the working voltage corresponds to a pull-up resistor.

Referring to fig. 4, in some possible embodiments, the above-mentioned switching tube driving device may further include: the fault feedback module 400 is connected with the feedback end of the outer tube driving module 100, and is used for feeding back the working state of the outer tube to external equipment.

Referring to fig. 5, in the present embodiment, the fault feedback module 400 may include: the input end of the sixth buffer G6 is connected with the feedback end of the first driving optocoupler Um, and the output end of the sixth buffer G6 is connected with the VCE fault feedback interface.

In this embodiment, an external device (for example, a DSP (DIGITAL SIGNAL processor) control end) may obtain, by accessing the VCE fault feedback interface, a fault feedback signal from a feedback end of the first driving optocoupler Um, so as to further obtain a working state of the outer tube in the three-level topology.

In order to more intuitively embody the function of the switching tube driving device provided by this embodiment, the working principle of the switching tube driving device is now described with reference to fig. 6 and 7, which are obtained by the switching tube driving device shown in fig. 5 and the I-type three-level NPC topology shown in fig. 2:

when the three-level topology is short-circuited, the working states of the two bridge arm currents with the largest currents are as follows:

referring to fig. 6, when the bridge arms S1 and S2 are turned on and the bridge arm currents are turned off as shown by the dashed lines in fig. 6, a short circuit occurs in the bridge arm or the output during the process of flowing from the bus dc+ to the output Ux, if the inner tube S2 is turned off before the outer tube S1, the bridge arm current will flow to the path of the output Ux through the bus DC-via D4 and D3 for commutation, in this case, the whole bus voltage and the peak voltage of the parasitic inductance of the loop will be borne by the S2, and the S2 will break down and break down due to the voltage stress;

Referring to fig. 7, when the bridge arms S3 and S4 are turned on and the bridge arm currents are shown by the dashed lines in fig. 7, in the process of flowing from the output Ux to the midpoint O of the bus, the bridge arm or the output is shorted, if the inner tube S3 is turned off before the outer tube S4, the bridge arm will flow to the dc+ path of the bus through the output Ux via the D2 and D1 for commutation, in this case, the bridge arm S3 will bear the whole bus voltage and the peak voltage of the parasitic inductance of the loop, and the bridge arm S3 will break down and break down due to voltage stress;

In order to avoid breakdown damage of the switching tube due to voltage stress, the embodiment uses the switching tube driving device in the above embodiment to perform short-circuit protection on the switching tube driving devices S1, S2 and S3, S4, where the switching tube driving device in fig. 6 is substantially identical to that in fig. 5, and the switching tube driving device in fig. 7 is obtained by folding the switching tube driving device in fig. 5 with the bridge arm midpoint as a symmetric center, it is not easy to see that PWM1, PWM4 are equivalent to the outer tube driving signals pwm_m, PWM2, PWM3 are equivalent to the inner tube driving signals pwm_n, U1, U4 are equivalent to the first driving optocouplers Um, U2, U3 are equivalent to the second driving optocouplers Un, VCC1, VCC4 are equivalent to the first positive voltages vcc_m, VCC2, VCC3 are equivalent to the second positive voltages vce_n, VEE1, VEE4 are equivalent to the first negative voltages vee_m, VEE3 are equivalent to the second negative voltages vee_n; after the three-level topology is protected based on the switching tube driving device, the working mode of the switching tube driving device is divided into the following two cases according to whether the three-level topology works normally or fails:

1) During normal operation, because the IGBT is conducted, the voltage drop between the IGBT C and the IGBT E is about 2V, the voltage drop between the IGBT C and the IGBT E is about 1V, the VCE+VD7 voltage is led into a DESAT pin of the driving optocoupler U1/U4 through the partial pressure of R3 and R4, but the voltage is lower than the reference voltage of an internal comparator of the driving optocoupler U1/U4, and the driving optocoupler U1/U4 normally transmits PWM driving signals;

2) When the three-level topology has short circuit FAULT, the IGBT enters a desaturation state, at the moment, the VCE voltage of an IGBT tube is far higher than the VCC power supply voltage, D7 is not conducted, the VCC voltage charges C1 through R2 and R3, the DESAT pin voltage rises, when the VCC voltage is higher than the internal comparison voltage, the driving optocoupler U1/U4 is closed to output, meanwhile, a FAULT signal of the U1/U4 low-voltage side FAULT is uploaded to a DSP control end through a VCE FAULT feedback interface, and the FUALT FAULT signal is respectively introduced into an AND gate circuit Y1 and Y2 through a logic management module, the transmission of an outer tube driving signal has no intermediate delay, the quick response can be realized in nanosecond time, and the switching-off interlocking of the outer tube IGBT is realized; and a delay circuit formed by R5 and C2 is added in the middle of transmission of the inner tube driving signal, the inner tube is turned off in a delayed manner, delay time with different lengths is set according to different power grades, the bridge arm IGBT outer tube is controlled before the inner tube is turned off, and the IGBT short-circuit protection function is realized.

Based on the switching tube driving device, the outer tube in the three-level topology is controlled to be turned off before the inner tube, so that the following effects can be achieved:

Referring to fig. 8, since S1 is turned off before S2, the unreasonable commutation path (bus DC-flowing to output Ux through D4, D3) is changed to the reasonable path (bus midpoint O flowing to output Ux through D5, S2), the commutation path is changed such that S1, S2 both bear half bus voltage, and the commutation path is halved in size, the parasitic inductance spike voltage is correspondingly reduced, protecting S2 from voltage stress damage;

Referring to fig. 9, since S4 is turned off before S3, the unreasonable commutation path (bus DC-flowing to the output Ux through D4, D3) is changed to the reasonable path (bus midpoint O flowing to the output Ux through D5, S2), the commutation path is changed so that S3, S4 are both subjected to half bus voltage, and the commutation path is halved in size, the peak voltage of parasitic inductance is correspondingly reduced, and S3 is protected from voltage stress.

In addition, the embodiment of the application also provides electronic equipment, which comprises the I-type three-level NPC topology and the switching tube driving device provided by any embodiment, wherein the switching tube driving device is used for driving the outer tube and the inner tube which are positioned on the same side of the middle point of the bridge arm in the I-type three-level NPC topology.

As an example, the electronic device may be a photovoltaic inverter, wind power converter, energy storage converter (PCS, power Conversion System), high voltage inverter, UPS, APF/SVG, high frequency power supply, etc. devices that employ a type I three level NPC topology.

The electronic device according to the present embodiment and the switching tube driving device according to the foregoing embodiments belong to the same technical concept, and technical details not described in detail in the present embodiment may be found in any of the foregoing embodiments, and the present embodiment has the same beneficial effects as those of each embodiment of the foregoing switching tube driving device.

It should be noted that the technical solutions of the embodiments of the present application may be combined with each other, but it is necessary to be based on that the skilled person can realize that when the combination of the technical solutions contradicts or cannot be realized, it should be considered that the combination of the technical solutions does not exist, and is not within the protection scope of the embodiments of the present application.

The foregoing description is only the preferred embodiments of the present application, and is not intended to limit the scope of the embodiments of the present application, but rather the equivalent structures or equivalent flow changes made by the descriptions of the embodiments of the present application and the contents of the drawings, or the direct or indirect application in other related technical fields, are all included in the scope of the embodiments of the present application.

Claims

1. A switching tube driving device for driving an outer tube and an inner tube located on the same side of a bridge arm midpoint in an I-type three-level NPC topology, the switching tube driving device comprising: an outer tube driving module, an inner tube driving module and a logic management module;

2. The switching tube driving device according to claim 1, wherein the outer tube driving module comprises: the first isolation unit, the first driving optocoupler and the voltage detection unit;

3. The switching tube driving device according to claim 2, wherein the first isolation unit comprises: the first buffer, the first AND gate, the first resistor and the second buffer;

4. The switching tube driving device according to claim 2, wherein the voltage detecting unit includes: the second resistor, the third resistor, the fourth resistor, the first capacitor and the comparison diode;

5. The switching tube driving device according to claim 1, wherein the inner tube driving module comprises: the second isolation unit and the second driving optocoupler;

6. The switching tube driving device as claimed in claim 5, wherein the second isolation unit comprises: the third buffer, the second AND gate, the delay circuit and the fourth buffer;

7. The switching tube driving device as claimed in claim 6, wherein the delay circuit comprises: a fifth resistor and a second capacitor;

8. The switching tube driving device as claimed in claim 1, wherein the logic management module comprises: a sixth resistor, a third capacitor and a fifth buffer;

9. The switching tube driving device according to claim 1, further comprising: a fault feedback module;

10. An electronic device, characterized in that the electronic device comprises a switching tube driving device according to any one of claims 1 to 9.