De-saturation short-circuit protection circuit and method of power switch device and new energy vehicle

Abstract

The invention discloses a desaturation short-circuit protection circuit and method of a power switching device and a new energy vehicle, and relates to the technical field of motor controllers, the desaturation short-circuit protection circuit of the power switching device comprises a driving module, a divider resistor and a diode, the driving module comprises a switching tube and a comparator, and a time delay module is arranged in the switching tube; the driving module is used for controlling the switching tube to be switched off under the condition that the actual conduction duration of the switching tube reaches the target conduction duration; the divider resistor is used for dividing voltage to obtain desaturation voltage of the driving module after the switching tube is switched off; and the driving module is also used for controlling the comparator to turn over under the condition that the desaturation voltage is greater than a preset comparator turn-over voltage threshold value so as to start desaturation short-circuit protection on the power switch device. The circuit provided by the invention can quickly respond to short-circuit protection of the power switch device on the basis of ensuring low power consumption and high robustness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor controller, in particular to a power switching device desaturation short-circuit protection circuit, method and new energy vehicle. BACKGROUND

[0002] When the Desat circuit protects the power switching device (such as SiC MOSFET) from short circuit, the short circuit time that the power switching device can withstand is very short, which requires the Desat short-circuit protection circuit to respond quickly to the short circuit protection of the power switching device.

[0003] Currently, the charging time of the Desat capacitor is shortened by increasing the charging speed of the current source / voltage source on the Desat capacitor or by reducing the capacitance value of the Desat capacitor, so as to realize the fast response of the Desat short-circuit protection circuit to the short circuit protection of the power switching device. However, the former will increase the power consumption of the current source and the voltage source, and the latter will reduce the robustness of the Desat short-circuit protection circuit.

[0004] Therefore, how to provide a Desat short-circuit protection circuit capable of quickly responding to the short circuit protection of the power switching device on the basis of ensuring low power consumption and high robustness is a problem to be solved at present. SUMMARY

[0005] The main purpose of the present application is to provide a power switching device desaturation short-circuit protection circuit, which aims to quickly respond to the short circuit protection of the power switching device on the basis of ensuring low power consumption and high robustness.

[0006] To achieve the above purpose, the present application provides a power switching device desaturation short-circuit protection circuit, which comprises a driving module, a voltage dividing resistor and a diode, the driving module comprises a switch tube and a comparator, and the switch tube is provided with a delay module;

[0007] The first end of the voltage dividing resistor is connected to the driving module and the anode of the diode, respectively, the second end of the voltage dividing resistor is grounded, and the cathode of the diode is connected to the drain of the power switching device.

[0008] The driving module is used for controlling the switch tube to be turned off when the actual conduction time of the switch tube reaches the target conduction time, wherein the target conduction time is the sum of the initial conduction time of the switch tube and the delay time of the delay module.

[0009] The voltage dividing resistor is used for dividing the desaturation voltage of the driving module after the switch tube is turned off.

[0010] The drive module is further configured to control the comparator to flip over to enable the desaturation short-circuit protection of the power switch device when the desaturation voltage is greater than a preset comparator flip-over voltage threshold.

[0011] In an embodiment, when the power switch device is normally turned on, the voltage dividing resistor divides a target voltage to obtain the desaturation voltage of the drive module, wherein the target voltage is a sum of a drain-source voltage of the power switch device and a conduction voltage of the diode.

[0012] When the power switch device is short-circuited, the voltage dividing resistor divides a power supply voltage of the desaturation short-circuit protection circuit to obtain the desaturation voltage of the drive module.

[0013] In an embodiment, the drive module comprises a charging unit.

[0014] The first output end of the comparator is connected to the charging unit, the first end of the voltage dividing resistor and the drain of the switch tube, and the second output end of the comparator is grounded.

[0015] In an embodiment, the charging unit comprises a current source and a first charging resistor.

[0016] The first end of the current source and the first end of the first charging resistor are connected to the first output end of the comparator, and the second end of the current source is connected to the second end of the first charging resistor.

[0017] Alternatively, the charging unit comprises a voltage source and a first charging resistor.

[0018] The first end of the first charging resistor is connected to the first output end of the comparator, and the second end of the first charging resistor is connected to the voltage source.

[0019] In an embodiment, the desaturation short-circuit protection circuit of the power switch device further comprises a bypass capacitor connected in parallel with the voltage dividing resistor.

[0020] The bypass capacitor is configured to filter out interference signals in the desaturation short-circuit protection circuit.

[0021] In an embodiment, the desaturation short-circuit protection circuit of the power switch device further comprises a current limiting resistor.

[0022] The first end of the current limiting resistor is connected to the first end of the voltage dividing resistor, and the second end of the current limiting resistor is connected to the anode of the diode.

[0023] In an embodiment, the desaturation short-circuit protection circuit of the power switch device further comprises a charging module.

[0024] The first end of the charging module is connected to the driving module, and the second end of the charging module is connected to the first end of the voltage dividing resistor and the anode of the diode, respectively.

[0025] In an embodiment, the charging module comprises an external power supply and a second charging resistor.

[0026] The output end of the external power supply is connected to the driving module and the first end of the second charging resistor, and the second end of the second charging resistor is connected to the first end of the voltage dividing resistor and the anode of the diode, respectively.

[0027] To achieve the above object, the application further provides a desaturation short-circuit protection method of a power switching device, which is applied to the desaturation short-circuit protection circuit of the power switching device.

[0028] If the opening instruction of the power switching device is detected, the power switching device is opened, and the switch tube of the driving module of the desaturation short-circuit protection circuit is controlled to be turned on, and the actual conduction duration of the switch tube is recorded.

[0029] If the actual conduction duration reaches a target conduction duration, the switch tube is controlled to be turned off, wherein the target conduction duration is the sum of the initial conduction duration of the switch tube and the delay duration of the delay module arranged in the switch tube.

[0030] After the switch tube is controlled to be turned off, the desaturation voltage of the driving module is obtained through the voltage dividing of the voltage dividing resistor of the desaturation short-circuit protection circuit.

[0031] If the desaturation voltage is greater than a preset comparator flip voltage threshold value, the comparator in the driving module is controlled to be flipped to start the desaturation short-circuit protection of the power switching device.

[0032] To achieve the above object, the application further provides a new energy vehicle, which comprises the desaturation short-circuit protection circuit of the power switching device.

[0033] To achieve the above object, the application further provides a computer readable storage medium, which stores a program for implementing the desaturation short-circuit protection method of the power switching device.

[0034] The application provides a desaturation short-circuit protection circuit of a power switch device, which comprises a diode connected with a drain of the power switch device; a driving module comprising a switch tube and a comparator, wherein the switch tube comprised in the driving module is provided with a delay module, and the delay module can prolong an initial conduction time length of the switch tube to a target conduction time length, so that the driving module needs to control the switch tube to be turned off after the actual conduction time length of the switch tube reaches the target conduction time length, to perform a subsequent short-circuit protection operation. Thus, it can be ensured that the desaturation short-circuit protection circuit performs the short-circuit protection after the power switch device is turned on. Thus, the technical defect that the drain-source voltage of the power switch device cannot be lowered in time due to a slow turn-on speed of the power switch device under some working conditions, thereby causing the desaturation short-circuit protection circuit to malfunction, is overcome, and the robustness of the desaturation short-circuit protection circuit is improved.

[0035] Further, the desaturation short-circuit protection circuit of the power switch device further comprises a voltage dividing resistor connected with the driving module and the anode of the diode respectively, and the voltage dividing resistor is used to divide a desaturation voltage of the driving module after the switch tube is turned off. Since the voltage dividing resistor does not need to go through a charging process to complete voltage division directly compared with the Desat capacitor, the charging speed of the current source / voltage source does not need to be increased, the short-circuit protection of the power switch device can be responded quickly, and the situation that the power consumption is increased due to the increase of the charging speed of the current source / voltage source is avoided; and the driving module can control the comparator to flip quickly in the case that the desaturation voltage is greater than a preset comparator flip voltage threshold, to make up for the time delay of the delay module to the desaturation short-circuit protection circuit when responding to the short-circuit protection, so that the desaturation short-circuit protection circuit can respond to the short-circuit protection of the power switch device quickly.

[0036] Therefore, the desaturation short-circuit protection circuit of the power switch device provided by the application can respond to the short-circuit protection of the power switch device quickly on the basis of ensuring low power consumption and high robustness. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of the drawings shown.

[0038] Figure 1 It is a structural schematic diagram of the existing desaturation short-circuit protection circuit;

[0039] Figure 2The waveform diagram of the existing desaturation short-circuit protection circuit when the power switching device is short-circuited;

[0040] Figure 3 This is a schematic diagram of the first embodiment of the desaturation short-circuit protection circuit for the power switching device of this application;

[0041] Figure 4 This is a schematic diagram of a structure of an embodiment of the drive module in the desaturation short-circuit protection circuit of the power switching device of this application, which includes a charging unit, a comparator and a switching transistor.

[0042] Figure 5 This is a schematic diagram of a structure of an embodiment of the charging unit in the desaturation short-circuit protection circuit of the power switching device of this application, which includes a current source and a first charging resistor.

[0043] Figure 6 This is a schematic diagram of the second embodiment of the desaturation short-circuit protection circuit for the power switching device of this application;

[0044] Figure 7 This is a schematic diagram of the third embodiment of the desaturation short-circuit protection circuit for the power switching device of this application;

[0045] Figure 8 This is a schematic diagram of the fourth embodiment of the desaturation short-circuit protection circuit for the power switching device of this application.

[0046] Figure 9 This is a schematic diagram of a structure of an embodiment of the charging module in the desaturation short-circuit protection circuit of the power switching device of this application, which includes an external power supply and a second charging resistor.

[0047] Figure 10 This is a schematic diagram of the desaturation short-circuit protection circuit of the power switching device after combining the various embodiments of this application;

[0048] Figure 11 for Figure 10 The waveform diagram of the desaturation short-circuit protection circuit of the power switching device is shown when the power switching device is normally turned on.

[0049] Figure 12 for Figure 10 The waveform diagram of the desaturation short-circuit protection circuit of the power switching device shown is displayed when the power switching device is short-circuited.

[0050] Figure 13 This is a flowchart illustrating an embodiment of the desaturation short-circuit protection method for power switching devices in this application.

[0051] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0052] Explanation of icon numbers:

[0053] 10. Drive module; 20. Charging module; 11. Charging unit; C1. Desat capacitor; C2. Bypass capacitor; D1. Diode; T1. Power switching device; T2. Switching transistor; Rx. Voltage divider resistor; U1. Comparator; I1. Current source; R1. First charging resistor; R2. Second charging resistor; R3. Current limiting resistor; Vcc. External power supply. Detailed Implementation

[0054] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0055] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0056] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0057] The principle underlying the Desat circuit's short-circuit protection for power switching devices T1 (such as SiC MOSFETs) can be found in [reference needed]. Figure 1 When the power switching device T1 is short-circuited, its drain-source voltage Vds will increase, causing the diode D1 to be cut off. At this time, the Desat capacitor C1 can be charged to a preset threshold through a voltage source or current source, causing the comparator U1 in the drive module 10 to flip and output a low level, thereby turning off the power switching device T1.

[0058] When Desat circuits provide short-circuit protection for power switching devices, the short-circuit time that the power switching devices can withstand is very short. This requires the desaturation short-circuit protection circuit to respond quickly enough to protect the power switching devices from short circuits.

[0059] At present, the charging time of the Desat capacitor is usually shortened by increasing the charging speed of the current / voltage source to the Desat capacitor or by reducing the capacitance of the Desat capacitor, so as to realize the fast response of the Desat short-circuit protection circuit to the short-circuit protection of the power switch device. However, the former will increase the power consumption of the current and voltage sources, and the latter will reduce the robustness of the Desat short-circuit protection circuit.

[0060] The reasons why the Desat capacitor with small capacitance reduces the robustness of the Desat short-circuit protection circuit mainly include the following two points: one is that the Desat capacitor with small capacitance has poor anti-interference performance; the other is that the drain-source voltage of the power switch device cannot be lowered in time under some working conditions, thereby causing the misoperation of the Desat short-circuit protection circuit. The understanding of the second reason can be referred to Figure 2 When the gate-on instruction starts, that is, V Ton / Toff When the gate-on instruction starts, that is, V Ton / Toff When the gate-on instruction starts, that is, V Figure 1 As shown in the drive module 10, the switch tube T2 is disconnected, the Desat capacitor C1 starts to be charged to the preset threshold value by the voltage source or the current source, so that the comparator U1 in the drive module 10 is reversed. Therefore, when the turn-on speed of the power switch device T1 is slow, the drain-source voltage Vds of the power switch device T1 cannot be lowered within the Tblank time, and the diode D1 is cut off, so that the Desat short-circuit protection circuit will cause the Desat capacitor C1 to start charging at the disconnection time point of the switch tube T2 due to the high drain-source voltage Vds of the power switch device T1, thereby causing the misoperation of the Desat short-circuit protection circuit.

[0061] Therefore, how to provide a Desat short-circuit protection circuit capable of fast responding to the short-circuit protection of the power switch device while ensuring low power consumption and high robustness is a problem to be solved at present.

[0062] Based on this, the present application provides a Desat short-circuit protection circuit for a power switch device. In the first embodiment of the present application, please refer to Figure 3The desaturation short-circuit protection circuit of the power switching device comprises a driving module 10, a voltage dividing resistor Rx and a diode D1, the driving module 10 comprising a switch tube T2 and a comparator U1, and the switch tube T2 being provided with a delay module; a first end of the voltage dividing resistor Rx is connected to the driving module 10 and an anode of the diode D1 respectively, a second end of the voltage dividing resistor Rx is grounded, and a cathode of the diode D1 is connected to a drain of the power switching device T1; the driving module 10 is used to control the switch tube T2 to be turned off when an actual conduction time of the switch tube T2 reaches a target conduction time, wherein the target conduction time is a sum of an initial conduction time of the switch tube T2 and a delay time of the delay module; the voltage dividing resistor Rx is used to obtain a desaturation voltage Vdesat of the driving module 10 by voltage division after the switch tube T2 is turned off; and the driving module 10 is further used to control the comparator U1 to be reversed to start the desaturation short-circuit protection of the power switching device T1 when the desaturation voltage Vdesat is greater than a preset comparator reversal voltage threshold Vdesat_th.

[0063] It should be noted that the switch tube T2 refers to a controllable switch with opening and closing functions, and the switch tube T2 can be a relay, a thyristor, a transistor, a field effect transistor, etc., and the embodiment does not make specific limitation on this. The delay module can comprise a timer, a delay timer or a delay circuit, etc., and the embodiment does not make specific limitation on the composition of the delay module.

[0064] In a feasible implementation, if the power switching device T1 is normally conducted, the voltage dividing resistor Rx performs voltage division on a target voltage to obtain the desaturation voltage Vdesat of the driving module 10, wherein the target voltage is a sum of a drain-source voltage Vds of the power switching device T1 and a conduction voltage of the diode D1; and if the power switching device T1 is short-circuited, the voltage dividing resistor Rx performs voltage division on a power supply voltage of the desaturation short-circuit protection circuit to obtain the desaturation voltage Vdesat of the driving module 10.

[0065] It can be understood that, since the voltage divided by the voltage dividing resistor Rx is the sum of the drain-source voltage Vds of the power switching device T1 and the on voltage of the diode D1 when the power switching device T1 is normally turned on, the voltage divided by the voltage dividing resistor Rx is small, and thus the final desaturation voltage Vdesat of the drive module 10 is also small and is less than the comparator flip voltage threshold Vdesat_th, so that the comparator U1 in the drive module 10 does not flip; when the power switching device T1 is short-circuited, the diode D1 is cut off, and the voltage dividing resistor Rx directly divides the power supply voltage of the desaturation short-circuit protection circuit, since the power supply voltage is large, the final desaturation voltage Vdesat of the drive module 10 is also large and is greater than the comparator flip voltage threshold Vdesat_th, so that the comparator U1 in the drive module 10 flips.

[0066] The embodiment provides a desaturation short-circuit protection circuit of a power switching device, which comprises a diode D1 connected with a drain of the power switching device; a drive module 10 comprising a switch tube T2 and a comparator U1, wherein the drive module 10 comprises a delay module in the switch tube T2, and the delay module can prolong the initial conduction time of the switch tube T2 to a target conduction time, so that the drive module 10 needs to control the switch tube T2 to be turned off after the actual conduction time of the switch tube T2 reaches the target conduction time, to perform subsequent short-circuit protection operation. Thus, it can be ensured that the desaturation short-circuit protection circuit performs short-circuit protection only after the power switching device T1 is turned on. Thus, the technical defect that the drain-source voltage cannot be lowered in time due to the slow turn-on speed of the power switching device T1 under some working conditions, thereby causing the desaturation short-circuit protection circuit to malfunction, is overcome, and the robustness of the desaturation short-circuit protection circuit is improved.

[0067] Further, the desaturation short-circuit protection circuit of the power switching device further comprises a voltage dividing resistor Rx connected with the drive module 10 and an anode of the diode D1 respectively, and the voltage dividing resistor Rx is used to divide the desaturation voltage of the drive module 10 after the switch tube T2 is turned off. Since the voltage dividing resistor Rx does not need to go through a charging process to complete voltage division, the charging speed of the current source / voltage source does not need to be increased, the short-circuit protection of the power switching device T1 can be quickly responded, and the situation that the power consumption is increased due to the increase of the charging speed of the current source / voltage source is avoided; and the drive module 10 can quickly control the comparator U1 to flip when the desaturation voltage is greater than the preset comparator U1 flip voltage threshold, to make up for the time delay of the delay module to the desaturation short-circuit protection circuit when responding to the short-circuit protection, so that the desaturation short-circuit protection circuit can quickly respond to the short-circuit protection of the power switching device T1.

[0068] Therefore, the desaturation short-circuit protection circuit of the power switch device T1 provided by the embodiment can quickly respond to the short-circuit protection of the power switch device T1 on the basis of ensuring low power consumption and high robustness.

[0069] In a possible implementation, referring to Figure 4 , the driving module 10 can include a charging unit 11; a first output end of the comparator U1 is connected to the charging unit 11, a first end of a voltage dividing resistor Rx, and a drain of a switch tube T2 respectively, and a second output end of the comparator U1 is grounded together with a source of the switch tube T2.

[0070] For the composition of the charging unit 11, in a possible implementation, referring to Figure 5 , the charging unit 11 can include a current source I1 and a first charging resistor R1, a first end of the current source I1 and a first end of the first charging resistor R1 are connected to the first output end of the comparator U1, and a second end of the current source I1 is connected to a second end of the first charging resistor R1.

[0071] In another possible implementation, the charging unit 11 can include a voltage source V1 and a first charging resistor R1, a first end of the first charging resistor R1 is connected to the first output end of the comparator U1, and a second end of the first charging resistor R1 is connected to the voltage source V1.

[0072] It should be noted that the specific composition of the charging unit 11 is not specifically limited in the embodiment.

[0073] Based on the first embodiment, a second embodiment of the desaturation short-circuit protection circuit of the power switch device is provided, and in the second embodiment of the desaturation short-circuit protection circuit of the power switch device, referring to Figure 6 , the desaturation short-circuit protection circuit of the power switch device can further include a bypass capacitor C2 connected in parallel with the voltage dividing resistor Rx; the bypass capacitor C2 is configured to filter out interference signals in the desaturation short-circuit protection circuit.

[0074] It should be noted that the bypass capacitor C2 is usually a capacitor with a very small capacitance, for example, a 10 PF capacitor.

[0075] The embodiment filters out interference signals in the circuit by connecting the bypass capacitor C2 in parallel with the voltage dividing resistor Rx, so as to enhance the anti-interference ability of the desaturation short-circuit protection circuit without affecting the response time of the desaturation short-circuit protection circuit of the power switch device T1.

[0076] Based on the first embodiment and / or the second embodiment, a third embodiment of the desaturation short-circuit protection circuit of the power switching device is provided, and in the third embodiment of the desaturation short-circuit protection circuit of the power switching device, please refer to Figure 7 The desaturation short-circuit protection circuit of the power switching device can further include a current-limiting resistor R3; a first end of the current-limiting resistor R3 is connected to a first end of the voltage-dividing resistor Rx, and a second end of the current-limiting resistor R3 is connected to an anode of the diode D1.

[0077] In this embodiment, the current-limiting resistor R3 is added to the desaturation short-circuit protection circuit to limit and stabilize the current in the circuit, so as to avoid short-circuit and overload problems caused by excessive current in the circuit, and the safety of the desaturation short-circuit protection circuit is improved.

[0078] Based on the first embodiment, the second embodiment and / or the third embodiment, a fourth embodiment of the desaturation short-circuit protection circuit of the power switching device is provided, and in the fourth embodiment of the desaturation short-circuit protection circuit of the power switching device, please refer to Figure 8 The desaturation short-circuit protection circuit of the power switching device can further include a charging module 20; a first end of the charging module 20 is connected to the driving module 10, and a second end of the charging module 20 is respectively connected to a first end of the voltage-dividing resistor Rx and an anode of the diode D1.

[0079] It should be noted that the power supply voltage of the desaturation short-circuit protection circuit can be provided by the charging unit 11 in the driving module 10, can be provided by the charging module 20, or can be provided by both the charging unit 11 in the driving module 10 and the charging module 20, and this embodiment does not make a specific limitation.

[0080] In a possible implementation, please refer to Figure 9 The charging module 20 can include an external power supply Vcc and a second charging resistor R2; an output end of the external power supply Vcc is respectively connected to the driving module 10 and a first end of the second charging resistor R2, and a second end of the second charging resistor R2 is respectively connected to a first end of the voltage-dividing resistor Rx and an anode of the diode D1. In other implementations, an external current source can be used instead of the external power supply V2 in this embodiment, and the specific composition of the charging module 20 is not limited in this embodiment.

[0081] For the sake of understanding the implementation principle of the desaturation short-circuit protection circuit of the power switching device combined with the above embodiments, the desaturation short-circuit protection circuit of the power switching device shown in Figure 10 is taken as an example, and Figure 11 and Figure 12 are referred to, and specifically:

[0082] When the turn-on instruction (i.e. the turn-on instruction of the power switching device T1) starts, i.e. V Ton / Toff When the turn-on instruction (i.e. the turn-on instruction of the power switching device T1) starts, i.e. V Ton / Toff When the turn-on instruction (i.e. the turn-on instruction of the power switching device T1) starts, i.e. V Figure 11 When the turn-on instruction (i.e. the turn-on instruction of the power switching device T1) starts, i.e. V Figure 12 When the turn-on instruction (i.e. the turn-on instruction of the power switching device T1) starts, i.e. V

[0083] It should be noted that the above examples are only used to assist in understanding the present application and do not constitute a limitation on the power switching device desaturation short-circuit protection circuit. Based on this technical concept, more forms of simple transformation are within the protection scope of the present application.

[0084] The present application also provides a power switching device desaturation short-circuit protection method applied to the power switching device desaturation short-circuit protection circuit described above. Please refer to Figure 13 , and in combination with Figures 3 to 12 The method comprises steps S10-S40:

[0085] Step S10: If the turn-on instruction of the power switching device is detected, turn on the power switching device, control the switch tube of the drive module of the desaturation short-circuit protection circuit to be turned on, and record the actual turn-on duration of the switch tube.

[0086] Step S20: If the actual turn-on duration reaches the target turn-on duration, control the switch tube to be turned off, wherein the target turn-on duration is the sum of the initial turn-on duration of the switch tube and the delay duration of the delay module arranged in the switch tube.

[0087] Step S30: After controlling the switch tube to be turned off, the desaturation voltage of the drive module is obtained by voltage division of the voltage dividing resistor of the desaturation short-circuit protection circuit.

[0088] Step S40, if the desaturation voltage is greater than the preset comparator flip voltage threshold, the comparator flip in the control driving module is controlled to start the desaturation short-circuit protection of the power switch device.

[0089] The desaturation short-circuit protection method of the power switch device provided by the application is applied to the desaturation short-circuit protection circuit of the power switch device in the above embodiment, and can quickly respond to the short-circuit protection of the power switch device on the basis of ensuring low power consumption and high robustness. Compared with the prior art, the beneficial effects of the desaturation short-circuit protection method of the power switch device provided by the application are the same as those of the desaturation short-circuit protection circuit of the power switch device provided by the above embodiment, and will not be repeated here.

[0090] In addition, the application also provides a new energy vehicle, which comprises the above-mentioned desaturation short-circuit protection circuit of the power switch device. It can be understood that, since the above-mentioned desaturation short-circuit protection circuit of the power switch device is used in the new energy vehicle, the embodiment of the new energy vehicle comprises all the technical solutions of all the embodiments of the above-mentioned desaturation short-circuit protection circuit of the power switch device, and the technical effects achieved are also completely the same, and will not be repeated here.

[0091] The above is only the preferred embodiment of the application, and does not limit the patent scope of the application. Any equivalent structural transformation, direct / indirect application in other related technical fields based on the application concept, and the contents of the specification and drawings are included in the patent protection scope of the application.

Claims

1. A desaturation short-circuit protection circuit for a power switching device, characterized by, The desaturation short-circuit protection circuit of the power switching device comprises a driving module, a voltage dividing resistor and a diode, the driving module comprises a switching tube and a comparator, and a delay module is arranged in the switching tube; a first end of the voltage dividing resistor is connected with the driving module and an anode of the diode respectively, a second end of the voltage dividing resistor is grounded, and a cathode of the diode is connected with a drain of the power switching device; the driving module is configured to control the switching tube to be turned off when an actual conduction duration of the switching tube reaches a target conduction duration, wherein the target conduction duration is a sum of an initial conduction duration of the switching tube and a delay duration of the delay module; the voltage dividing resistor is configured to divide a voltage of the driving module after the switching tube is turned off; the driving module is further configured to control the comparator to be reversed to start the desaturation short-circuit protection of the power switching device when the desaturation voltage is greater than a preset comparator reversal voltage threshold.

2. The desaturation short circuit protection circuit for a power switching device according to claim 1, wherein If the power switching device is normally conducted, the voltage dividing resistor divides a target voltage to obtain the desaturation voltage of the driving module, wherein the target voltage is a sum of a drain-source voltage of the power switching device and a conduction voltage of the diode; If the power switching device is short-circuited, the voltage dividing resistor divides a power supply voltage of the desaturation short-circuit protection circuit to obtain the desaturation voltage of the driving module.

3. The desaturation short circuit protection circuit for a power switching device according to claim 1, wherein The driving module comprises a charging unit; a first output end of the comparator is connected with the charging unit, a first end of the voltage dividing resistor and a drain of the switching tube respectively, and a second output end of the comparator and a source of the switching tube are grounded.

4. The desaturation short circuit protection circuit for a power switching device according to claim 3, wherein The charging unit comprises a current source and a first charging resistor; a first end of the current source and a first end of the first charging resistor are connected with a first output end of the comparator, and a second end of the current source is connected with a second end of the first charging resistor; Alternatively, the charging unit comprises a voltage source and a first charging resistor; a first end of the first charging resistor is connected with a first output end of the comparator, and a second end of the first charging resistor is connected with the voltage source.

5. The desaturation short circuit protection circuit for a power switching device according to any one of claims 1 to 4, wherein The desaturation short-circuit protection circuit of the power switching device further comprises a bypass capacitor connected with the voltage dividing resistor in parallel; the bypass capacitor is configured to filter out interference signals in the desaturation short-circuit protection circuit.

6. The desaturation short circuit protection circuit for a power switching device according to any one of claims 1 to 4, wherein The desaturation short-circuit protection circuit of the power switching device further comprises a current limiting resistor; a first end of the current limiting resistor is connected with a first end of the voltage dividing resistor, and a second end of the current limiting resistor is connected with an anode of the diode.

7. The desaturation short circuit protection circuit for a power switching device according to any one of claims 1 to 4, wherein The desaturation short-circuit protection circuit of the power switching device further comprises a charging module; a first end of the charging module is connected with the driving module, and a second end of the charging module is connected with a first end of the voltage dividing resistor and an anode of the diode respectively.

8. The desaturation short circuit protection circuit for a power switching device according to claim 7, wherein The charging module comprises an external power supply and a second charging resistor; an output end of the external power supply is connected with the driving module and a first end of the second charging resistor respectively, and a second end of the second charging resistor is connected with a first end of the voltage dividing resistor and an anode of the diode respectively.

9. A desaturation short-circuit protection method of a power switching device, characterized by, The method applied to the desaturation short-circuit protection circuit of the power switch device in any one of claims 1 to 8, the method comprising: if the turn-on instruction of the power switch device is detected, turning on the power switch device, controlling the switch tube of the driving module of the desaturation short-circuit protection circuit to be turned on, and recording the actual turn-on duration of the switch tube; if the actual turn-on duration reaches a target turn-on duration, controlling the switch tube to be turned off, wherein the target turn-on duration is the sum of the initial turn-on duration of the switch tube and the delay duration of the delay module arranged in the switch tube; after the switch tube is controlled to be turned off, the desaturation voltage of the driving module is obtained by voltage division of the voltage dividing resistor of the desaturation short-circuit protection circuit; if the desaturation voltage is greater than a preset comparator flip voltage threshold, the comparator in the driving module is controlled to be flipped to start the desaturation short-circuit protection of the power switch device.

10. A new energy vehicle, characterized in that, The new energy vehicle comprises the desaturation short-circuit protection circuit of the power switch device in any one of claims 1 to 8.

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