Driving circuit protection method and driving circuit protection device

Abstract

The invention provides a drive circuit protection method and a three-phase motor drive circuit, and the method comprises the steps: obtaining the short circuit condition of a three-phase motor, which comprises the short circuit of any one phase output end of the three-phase motor and a bias voltage end, the high level of an overcurrent protection signal, and the turn-off of original six paths of PWM signals; when the short circuit condition of the three-phase motor is yes, opening a three-phase upper tube in the three-phase motor, including connecting a high-level voltage to a three-phase upper tube control signal output and connecting a low-level voltage to a three-phase lower tube control signal output; and judging whether the original six-path PWM signal is a high-level signal, if so, turning off control signal output of the three-phase upper tube and the three-phase lower tube, and controlling the original six-path PWM signal to be connected with the three-phase upper tube and the three-phase lower tube. Motor current can directly flow out through the upper tube and is prevented from flowing through a body diode or a parasitic triode, so that burnout of a transistor is avoided.

Description

Technical Field

[0001] The present application relates to the field of motor drive technology, and in particular to a drive circuit protection method and a drive circuit protection device. Background Art

[0002] When the motor is working normally, at a certain moment, switch S1 is closed, and OUTA is short-circuited with VBB (when the actual circuit is working, the short-circuit may be caused by dust and impurities, etc., which cause the VBB and OUT nodes to be short-circuited). Figure 1 As shown, Figure 1 It is a short-circuit schematic diagram of the three-phase motor drive circuit in the background technology. At this time, the OUTA node voltage is equal to VBB. When the lower tube of phase A is turned on, a path from VBB through the lower tube of phase A to GND will be formed, forming a large current. Thereby triggering the OCP circuit of the lower tube of phase A. When the OCP circuit is triggered, the six-way PWM wave generation will generally stop, that is, the three-phase upper and lower tubes will be turned off. At this time, phase A will generate a current from OUTA to phase B or C. Here we take the current from phase A to phase B as an example. Since the upper and lower tubes of the three phases are all turned off at this time, the current from phase A to phase B will flow to VBB through the body diode of the upper tube of phase B, and at the same time, the PNP parasitic transistor from the source of the upper tube of phase B to the substrate may be turned on, resulting in a large current from the source to the substrate. Thereby burning the upper tube of phase B.

[0003] When the OUTA node touches VBB, the power generated by the upper tube of phase B is:

[0004] P=UI=(VBB+0.7V)I B

[0005] It can be seen that the power depends on the power supply voltage VBB and the B-phase current IB. When the power supply voltage is high or the speed is high (i.e., high current), the power is large and it is easier to reach the threshold that the body diode or parasitic transistor can tolerate, thereby burning the transistor. Summary of the invention

[0006] The purpose of the present application is to provide a driving circuit protection method and a driving circuit protection device, which can make the motor current flow out directly through the upper tube, avoid the current flowing through the body diode or parasitic transistor, and thus avoid burning the transistor.

[0007] The embodiment of the present application is implemented as follows:

[0008] In one aspect of an embodiment of the present application, a driving circuit protection method is provided, which is applied to a three-phase motor driving circuit, comprising: obtaining a short-circuit condition of the three-phase motor, wherein the short-circuit condition of the three-phase motor includes that any one phase output terminal of the three-phase motor is short-circuited to a bias voltage terminal, an overcurrent protection signal is at a high level, and all original six-channel PWM signals are turned off;

[0009] When the short circuit condition of the three-phase motor is yes, the three-phase upper tubes in the three-phase motor are turned on, including connecting a high-level voltage to the three-phase upper tube control signal output and connecting a low-level voltage to the three-phase lower tube control signal output;

[0010] Determine whether the original six-channel PWM signal is a high-level signal. If so, turn off the control signal output of the three-phase upper tube and the three-phase lower tube, and control the original six-channel PWM signal to be connected to the three-phase upper tube and the three-phase lower tube.

[0011] Optionally, the three-phase motor short circuit situation also includes: the first upper tube control signal is a low level, the second upper tube control signal is a high level, the first lower tube control signal is a high level, and the second lower tube control signal is a low level.

[0012] Optionally, before obtaining the short-circuit condition of the three-phase motor, it also includes: judging whether the D-flip-flop set signal is at a low level. When the D-flip-flop set signal is at a low level, the three-phase upper tube control signal and the three-phase lower tube control signal are consistent with the original six-channel PWM signal.

[0013] Optionally, controlling the original six-way PWM signal to be connected to the three-phase upper tube and the three-phase lower tube includes: after connecting the original three-way upper tube PWM signal to the three-phase upper tube, after a preset delay time, connecting the original three-way lower tube PWM signal to the three-phase lower tube.

[0014] Optionally, when the short-circuit condition of the three-phase motor is yes, it also includes: after a preset short-circuit setting time, setting the output signal of the D trigger to 0.

[0015] Optionally, before obtaining the short-circuit condition of the three-phase motor, it also includes: detecting the lower tube current of any phase of the three-phase motor, and when the lower tube current is greater than a preset soft shutdown current threshold, shutting down the power tube corresponding to the lower tube current.

[0016] In another aspect of the embodiment of the present application, a driving circuit protection device is provided, comprising: a short circuit condition judgment module, a three-phase circuit signal control module, an original three-phase signal recovery module, a delay module, an overcurrent protection signal setting module and a soft shutdown module;

[0017] The short-circuit condition judgment module is used to obtain the short-circuit condition of the three-phase motor, wherein the short-circuit condition of the three-phase motor includes that any one phase output terminal of the three-phase motor is short-circuited with the bias voltage terminal, the overcurrent protection signal is at a high level, and all the original six-channel PWM signals are turned off;

[0018] The three-phase circuit signal control module is used to turn on the three-phase upper tubes in the three-phase motor when the short-circuit condition of the three-phase motor is yes, including connecting a high-level voltage to the three-phase upper tube control signal output and connecting a low-level voltage to the three-phase lower tube control signal output;

[0019] The original three-phase signal recovery module is used to determine whether the original six-way PWM signal is a high-level signal. If so, the control signal output of the three-phase upper tube and the three-phase lower tube is turned off, and the original six-way PWM signal is controlled to be connected to the three-phase upper tube and the three-phase lower tube;

[0020] The delay module is used to connect the original three-way lower tube PWM signal to the three-phase lower tube after a preset delay time after the original three-way upper tube PWM signal is connected to the three-phase upper tube;

[0021] The overcurrent protection signal setting module is used to set the overcurrent protection signal to a low level after a preset short circuit setting time;

[0022] The soft shutdown module is used to detect the lower tube current of any phase of the three-phase motor, and when the lower tube current is greater than a preset soft shutdown current threshold, shut down the power tube corresponding to the lower tube current.

[0023] Optionally, one end of the delay module is connected to the first upper tube control signal, and the other end is connected to the first lower tube control signal and a second inverter through a first inverter, and the other end of the second inverter is connected to the second lower tube control signal.

[0024] Optionally, the output end of the overcurrent protection signal setting module is connected to the D trigger, the D end of the D trigger is connected to the overcurrent protection signal, and the Q end is connected to the first upper tube control signal, the second upper tube control signal, the first lower tube control signal and the second lower tube control signal.

[0025] Optionally, the soft shutdown module is connected to the output end of the three-phase motor.

[0026] The beneficial effects of the embodiments of the present application include:

[0027] A driving circuit protection method and a driving circuit protection device provided in the embodiments of the present application can enable the motor current to flow out directly through the upper tube, avoiding the current flowing through the body diode or parasitic transistor, thereby avoiding burning of the transistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a short-circuit schematic diagram of a three-phase motor drive circuit in the background technology;

[0030] Figure 2 Schematic diagram of the process of the driving circuit protection method in the embodiment of the present application;

[0031] Figure 3 This is a schematic diagram of the structure of a three-phase motor drive circuit in an embodiment of the present application;

[0032] Figure 4 This is a control signal timing diagram of the driving circuit protection method in an embodiment of the present application;

[0033] Figure 5 This is a schematic diagram of the structure of the driving circuit protection device in the embodiment of the present application;

[0034] Figure 6 This is a schematic diagram of the structure of the delay module in the embodiment of the present application;

[0035] Figure 7 This is a schematic diagram of the signal level of the delay module in an embodiment of the present application;

[0036] Figure 8 This is a structural diagram of an overcurrent protection signal setting module in an embodiment of the present application;

[0037] Fig. 9 Schematic diagram of the structure of the soft shutdown module in the embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0040] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0041] In the description of the present application, it should be noted that the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0042] In one aspect of an embodiment of the present application, a drive circuit protection method is provided, which is applied to a three-phase motor drive circuit, such as Figure 2 As shown, Figure 2 The flowchart of the driving circuit protection method in the embodiment of the present application includes:

[0043] S101, obtaining a short-circuit condition of a three-phase motor, wherein the short-circuit condition of the three-phase motor includes a short circuit between an output terminal of any phase of the three-phase motor and a bias voltage terminal, an overcurrent protection signal being at a high level, and all original six-channel PWM signals being turned off.

[0044] This embodiment is to protect the driving circuit. When any phase of OUTA / B / C is short-circuited with VBB, current is prevented from flowing through the body diode or parasitic transistor, thereby preventing the transistor from burning. Therefore, it is necessary to first obtain the short-circuit condition of the three-phase motor, that is, to determine whether the three-phase motor is short-circuited. The basis for determining the short-circuit condition of the three-phase motor can be determined by detecting that the overcurrent protection signal is at a high level in this embodiment. And the control signals that originally control the six power tubes are all turned off, that is, at a low level to determine that a short circuit has occurred. Other methods can also be used, as long as it can be determined that a short circuit has occurred.

[0045] like Figure 3 As shown, Figure 3 The schematic diagram of the structure of the three-phase motor drive circuit in the embodiment of the present application, in which PWMAHS, PWMBHS, PWMCHS, PWMALS.PWMBLS, PWMCLS are the original control signals for the six power tubes, that is, the original six-way PWM signals. In addition, the input signals also include the OCPA / B / C three-way signals, the SET setting signal, the EN signal, the VREF voltage and the GND. The output signal is

[0046] PWMAHS_1, PWMBHS_1, PWMCHS_1, PWMALS_1. PWMBLS_1, PW MCLS_1, its working principle is to detect six PWM wave signals. When the motor is running normally, the six PWM waves will not all be low level. At the same time, when the motor is not started, even if the six PWM waves are all low level, the three OCP signals are not triggered, that is, they are all 0.

[0047] At this time, the circuit internal signal CTRLHS_1 is high level and CTRLHS_2 is low level, CTRLLS_1 is low level and CTRLLS_2 is high level. The transmission gate in the circuit selects the original input PWM control signal as the output, that is, at this time, the circuit outputs the signal PWMAHS_1, PWMBHS_1, PWMCHS_1, PWMALS_1.PWMBLS_1, PWMCL S_1

[0048] With output signal

[0049] PWMAHS, PWMBHS, PWMCHS, PWMALS. PWMBLS, and PWMCLS remain consistent.

[0050] When the OUTA / B / C node is short-circuited with VBB and OCP is triggered, the OCP signal of the corresponding phase will turn to high level, and the six PWM signals will all be turned off, that is, low level. At this time, the internal signal CTRLHS_1 of the circuit is low level, CTRLHS_2 is high level, CTRLLS_1 is high level, and CTRLLS_2 is low level.

[0051] S102, when the short circuit condition of the three-phase motor is yes, the three-phase upper tubes in the three-phase motor are turned on, including connecting a high-level voltage to the three-phase upper tube control signal output and connecting a low-level voltage to the three-phase lower tube control signal output.

[0052] It is easy to understand that when it is determined that the three-phase motor is short-circuited, the three-phase upper tube in the three-phase motor is turned on to release the motor current. Specifically, the circuit is driven by the new three-phase upper tube control signal, which is high level. The circuit is driven by the new three-phase lower tube control signal, which is low level, that is, PWMAHS_1, PWMBHS_1, PWMCHS_1

[0053] is high level, PWMALS_1.PWMBLS_1, PWMCLS_1 is low level. This action will force the three-phase upper tube to open to release the motor current, and close the three-phase lower tube at the same time to avoid chip burning.

[0054] S103, determining whether the original six-channel PWM signal is a high-level signal, if so, shutting down the control signal output of the three-phase upper tube and the three-phase lower tube, and controlling the original six-channel PWM signal to be connected to the three-phase upper tube and the three-phase lower tube.

[0055] It is easy to understand that after the motor encounters the OCP overcurrent protection trigger, it will try to restart the motor after a certain period of time, that is, the original six-way PWM wave starts to send a high-level signal. At this time, the transmission gate in the circuit disconnects the path from VREF and GND to PWMAHS_1, PWMBHS_1, PWMCHS_1 and PWMALS_1.PWMBLS_1, PWMCLS_1. Connect the original six-way PWM signals PWMAHS, PWMBHS, PWMCHS, PWMALS.PWMBLS, PWMCLS to the output

[0056] PWMAHS_1, PWMBHS_1, PWMCHS_1, PWMALS_1.PWMBLS_1, PWMCLS_1, to ensure the normal operation of the circuit.

[0057] Optionally, the three-phase motor short circuit situation also includes: the first upper tube control signal is a low level, the second upper tube control signal is a high level, the first lower tube control signal is a high level, and the second lower tube control signal is a low level.

[0058] It is easy to understand that when the OUTA / B / C node is short-circuited with VBB and OCP is triggered, the OCP signal of the corresponding phase will turn to a high level, and at the same time, all six PWM signals will be turned off, that is, at a low level. At this time, the internal circuit signal CTRLHS_1 is low, CTRLHS_2 is high, CTRLLS_1 is high, and CTRLLS_2 is low. In other words, when the first upper tube control signal is low, the second upper tube control signal is high, the first lower tube control signal is high, and the second lower tube control signal is low, it can also be determined that the three-phase circuit is short-circuited.

[0059] Optionally, before obtaining the short-circuit condition of the three-phase motor, it also includes: judging whether the D-flip-flop set signal is at a low level. When the D-flip-flop set signal is at a low level, the three-phase upper tube control signal and the three-phase lower tube control signal are consistent with the original six-channel PWM signal.

[0060] In this embodiment, the D flip-flop setting condition is used as the start enable terminal of the driving circuit protection method. When the D flip-flop setting signal, that is, the EN enable signal terminal is low, the D flip-flop is low, and the driving circuit protection method function in this embodiment is turned off, that is, the three-phase upper and lower tube control signals are still controlled by the original six-channel PWM signal, and when the EN enable signal terminal is high, the D flip-flop is high. The driving circuit protection method is controlled based on the OCP judgment condition.

[0061] Optionally, controlling the original six-way PWM signal to be connected to the three-phase upper tube and the three-phase lower tube includes: after connecting the original three-way upper tube PWM signal to the three-phase upper tube, after a preset delay time, connecting the original three-way lower tube PWM signal to the three-phase lower tube.

[0062] In this embodiment, if Figure 4 As shown, Figure 4 This is a control signal timing diagram of the driving circuit protection method in the embodiment of the present application. Before OCP occurs in phase A, PWMBHS is equal to PWMBHS_1, PWMBLS is equal to PWMBLS_1, and after phase A OCP, after t1 time, the PWM signal stops emitting waves, and after t2 time, PWMBHS_1 is forced to a high level to turn on the corresponding upper tube. PWMBLS_1 ​​is forced to a low level to turn off the corresponding lower tube. After the restart time t3, the high-side signal PWMBHS is first transmitted to PWMBHS_1, and after a t4 time delay, the low-side signal PWMBLS is transmitted to PWMBLS_1. Since the three-phase upper tube is in the open state at the previous moment, if the lower tube is controlled to be turned on at this time, the upper and lower tubes are turned on at the same time to form a large VDD-GND current to burn the chip.

[0063] Optionally, when the short-circuit condition of the three-phase motor is yes, it also includes: after a preset short-circuit setting time, setting the output signal of the D trigger to 0.

[0064] After a short circuit occurs, the OCP state will be latched into the D flip-flop, that is, the output Q is always high. If the motor stops at this time, the six PWM waves PWMAHS, PWMBHS, PWMCHS, PWMALS. PWMBLS, and PWMCLS will all turn low. This causes the aforementioned logic to work, forcing the three-way tube to open, and the operation is abnormal. Therefore, in this embodiment, after the preset short circuit setting time, the D flip-flop needs to be reset, and the output Q1 output signal of the D flip-flop needs to be set to 0 to avoid erroneously triggering the protection process after the short circuit.

[0065] Optionally, before obtaining the short-circuit condition of the three-phase motor, it also includes: detecting the lower tube current of any phase of the three-phase motor, and when the lower tube current is greater than a preset soft shutdown current threshold, shutting down the power tube corresponding to the lower tube current.

[0066] It is easy to understand that when VBB and OUT terminals touch, a large current flows through the lower tube to trigger OCP. At this time, a relatively fast soft shut-off circuit is generally required. Before the OCP responds, the lower tube gate starts to be pulled down to softly shut down the lower tube. This embodiment can quickly detect the voltage of the lower tube and the current flowing through the lower tube in real time by setting a soft shut-off module, further protecting the circuit from burning.

[0067] The following describes the device corresponding to the driving circuit protection method provided in the present application for executing. The specific implementation process and technical effects are described above and will not be repeated below.

[0068] Another aspect of the present application provides a driving circuit protection device, such as Figure 5 As shown, Figure 5 This is a schematic diagram of the structure of the driving circuit protection device in the embodiment of the present application. It includes: a short circuit situation judgment module, a three-phase circuit signal control module, an original three-phase signal recovery module, a delay module, an overcurrent protection signal setting module and a soft shutdown module;

[0069] The short-circuit condition judgment module is used to obtain the short-circuit condition of the three-phase motor, wherein the short-circuit condition of the three-phase motor includes that any one phase output terminal of the three-phase motor is short-circuited with the bias voltage terminal, the overcurrent protection signal is at a high level, and all the original six-channel PWM signals are turned off;

[0070] The three-phase circuit signal control module is used to turn on the three-phase upper tubes in the three-phase motor when the short-circuit condition of the three-phase motor is yes, including connecting a high-level voltage to the three-phase upper tube control signal output and connecting a low-level voltage to the three-phase lower tube control signal output;

[0071] The original three-phase signal recovery module is used to determine whether the original six-way PWM signal is a high-level signal. If so, the control signal output of the three-phase upper tube and the three-phase lower tube is turned off, and the original six-way PWM signal is controlled to be connected to the three-phase upper tube and the three-phase lower tube;

[0072] The delay module is used to connect the original three-way lower tube PWM signal to the three-phase lower tube after a preset delay time after the original three-way upper tube PWM signal is connected to the three-phase upper tube;

[0073] The overcurrent protection signal setting module is used to set the overcurrent protection signal to a low level after a preset short circuit setting time;

[0074] The soft shutdown module is used to detect the lower tube current of any phase of the three-phase motor, and when the lower tube current is greater than a preset soft shutdown current threshold, shut down the power tube corresponding to the lower tube current.

[0075] Optionally, one end of the delay module is connected to the first upper tube control signal, and the other end is connected to the first lower tube control signal and a second inverter through a first inverter, and the other end of the second inverter is connected to the second lower tube control signal.

[0076] like Figure 6 As shown, Figure 6This is a schematic diagram of the structure of the delay module in the embodiment of the present application. The principle of the delay module is to form a delay through the charging and discharging of the capacitor. In the aforementioned driving circuit protection method, the delay unit is placed between CTRL_HS_1 and another inverter (that is, the input VIN of the delay unit is connected to CTRL_HS_1). When CTRL_HS_1 turns from low to high, after a period of delay, the output turns from low to high. That is, when restarting, the lower tube control logic slightly delays the upper tube control logic. As follows Figure 7 As shown, Figure 7 Schematic diagram of the signal level of the delay module in the embodiment of the present application.

[0077] Optionally, the output end of the overcurrent protection signal setting module is connected to the D trigger, the D end of the D trigger is connected to the overcurrent protection signal, and the Q end is connected to the first upper tube control signal, the second upper tube control signal, the first lower tube control signal and the second lower tube control signal.

[0078] It is easy to understand that after a short circuit occurs in the above scheme, the OCP state will be latched into the D flip-flop, that is, the output Q is always high. If the motor stops at this time, the six PWM waves PWMAHS, PWMBHS, PWMCHS, PWMALS. PWMBLS, and PWMCLS will all turn low. This causes the above logic to work, forcing the three-way tube to open, and the work is abnormal. Therefore, based on this scheme, a set function can be added. After the protection logic works for a period of time, the D flip-flop is reset and the output Q1 is set to 0 to avoid false triggering.

[0079] like Figure 8 As shown, Figure 8 This is a schematic diagram of the structure of the overcurrent protection signal setting module in the embodiment of the present application, wherein the D flip-flops D1D2D3 and the clock CLK frequency determine the time from the protection function taking effect to the setting. EN_B can be the circuit enable reverse signal, which is 0 when the circuit works normally and 1 when powered on. CLK is the circuit clock signal. Users can adjust the number of D flip-flops to set the time according to their needs. In addition, this solution also reserves an EN port to turn off this circuit function. 0 means turn off, and 1 means enable.

[0080] Optionally, the soft shutdown module is connected to the output end of the three-phase motor.

[0081] In this embodiment, the soft shutdown module is used to detect whether the lower tube of the three-phase motor is overcurrent and shut it down in time. Therefore, the soft shutdown module is directly connected to the output end of the three-phase motor. When the VBB and OUT terminals touch, a large current flows through the lower tube to trigger OCP. At this time, a corresponding relatively rapid soft shutdown circuit is generally required. Before the OCP responds, the lower tube gate starts to be pulled down to softly shut down the lower tube. However, the threshold of the ordinary soft shutdown circuit needs to be carefully designed, and may vary greatly with PVT, and cannot meet a variety of working conditions. Therefore, a lower tube soft shutdown circuit that can detect the OUT terminal voltage is further proposed to improve the reliability of the chip. Fig. 9 As shown, Fig. 9 It is a structural schematic diagram of the soft shutdown module in the embodiment of the present application. A lower tube soft shutdown circuit that can detect the voltage at the OUT terminal. Wherein M1 is the lower tube of any one of the three phases, and VG is the gate drive signal. When the circuit is working normally and the lower tube is turned on, VG is a high level to drive the lower tube to turn on, and M2 will detect the lower tube current in proportion and flow through R1 to generate a voltage. If the current is small at this time, the generated M4 gate voltage is small, which is not enough to turn on M4, and the circuit works normally. If the lower tube current is too large at this time, the generated M4 gate voltage is large, M4 is turned on, VG starts to pull down, and M1 is turned off. The advantage of this solution is that the current flowing through the lower tube can be detected in real time, a reasonable soft shutdown threshold can be generated, and the circuit can be further protected from burning.

[0082] The above-mentioned device is used to execute the method provided by the aforementioned embodiment, and its implementation principle and technical effect are similar, which will not be repeated here.

[0083] The above modules may be one or more integrated circuits configured to implement the above methods, such as one or more application specific integrated circuits (ASICs), or one or more microprocessors, or one or more field programmable gate arrays (FPGAs). For another example, when a module is implemented in the form of a processing element scheduling program code, the processing element may be a general-purpose processor, such as a central processing unit (CPU) or other processor that can call program code. For another example, these modules may be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0084] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0085] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0086] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0087] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (English: processor) to perform some steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (English: Read-Only Memory, abbreviated: ROM), random access memory (English: RandomAccess Memory, abbreviated: RAM), disk or optical disk and other media that can store program codes.

[0088] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0089] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A drive circuit protection method, applied to a three-phase motor drive circuit, characterized in that: include: Obtaining a short-circuit condition of a three-phase motor, wherein the short-circuit condition of the three-phase motor includes a short circuit between an output terminal of any phase of the three-phase motor and a bias voltage terminal, an overcurrent protection signal being at a high level, and all original six-channel PWM signals being turned off; When the short circuit condition of the three-phase motor is yes, the three-phase upper tubes in the three-phase motor are turned on, including connecting a high-level voltage to the three-phase upper tube control signal output and connecting a low-level voltage to the three-phase lower tube control signal output; Determine whether the original six-channel PWM signal is a high-level signal. If so, turn off the control signal output of the three-phase upper tube and the three-phase lower tube, and control the original six-channel PWM signal to be connected to the three-phase upper tube and the three-phase lower tube.

2. The driving circuit protection method according to claim 1, characterized in that: The three-phase motor short circuit situation also includes: The first upper tube control signal is at a low level, the second upper tube control signal is at a high level, the first lower tube control signal is at a high level, and the second lower tube control signal is at a low level.

3. The driving circuit protection method according to claim 1, characterized in that: The method of obtaining the short circuit condition of the three-phase motor also includes: It is determined whether the D flip-flop set signal is at a low level. When the D flip-flop set signal is at a low level, the three-phase upper tube control signal and the three-phase lower tube control signal are consistent with the original six-channel PWM signal.

4. The driving circuit protection method according to claim 1, characterized in that: The controlling of connecting the original six-channel PWM signals to the three-phase upper tube and the three-phase lower tube comprises: After the original three-way upper tube PWM signals are connected to the three-phase upper tube, after a preset delay time, the original three-way lower tube PWM signals are connected to the three-phase lower tube.

5. The driving circuit protection method according to claim 1, characterized in that: When the three-phase motor is short-circuited, the method further includes: After a preset short-circuit setting time, the output signal of the D flip-flop is set to 0.

6. The driving circuit protection method according to claim 1, characterized in that: Before obtaining the short-circuit condition of the three-phase motor, the method further includes: The lower tube current of any phase of the three-phase motor is detected, and when the lower tube current is greater than a preset soft shutdown current threshold, the power tube corresponding to the lower tube current is shut down.

7. A drive circuit protection device, applied to a three-phase motor drive circuit, the drive circuit protection device comprising a short circuit condition judgment module, a three-phase circuit signal control module, an original three-phase signal recovery module, a delay module, an overcurrent protection signal setting module and a soft shutdown module; The short-circuit condition judgment module is used to obtain the short-circuit condition of the three-phase motor, wherein the short-circuit condition of the three-phase motor includes that any one phase output terminal of the three-phase motor is short-circuited with the bias voltage terminal, the overcurrent protection signal is at a high level, and all the original six-channel PWM signals are turned off; The three-phase circuit signal control module is used to turn on the three-phase upper tubes in the three-phase motor when the short-circuit condition of the three-phase motor is yes, including connecting a high-level voltage to the three-phase upper tube control signal output and connecting a low-level voltage to the three-phase lower tube control signal output; The original three-phase signal recovery module is used to determine whether the original six-way PWM signal is a high-level signal. If so, the control signal output of the three-phase upper tube and the three-phase lower tube is turned off, and the original six-way PWM signal is controlled to be connected to the three-phase upper tube and the three-phase lower tube; The delay module is used to connect the original three-way lower tube PWM signal to the three-phase lower tube after a preset delay time after the original three-way upper tube PWM signal is connected to the three-phase upper tube; The overcurrent protection signal setting module is used to set the overcurrent protection signal to a low level after a preset short circuit setting time; The soft shutdown module is used to detect the lower tube current of any phase of the three-phase motor, and when the lower tube current is greater than a preset soft shutdown current threshold, shut down the power tube corresponding to the lower tube current.

8. The driving circuit protection device according to claim 7, characterized in that: One end of the delay module is connected to the first upper tube control signal, and the other end is connected to the first lower tube control signal and a second inverter through a first inverter, and the other end of the second inverter is connected to the second lower tube control signal.

9. The driving circuit protection device according to claim 7, characterized in that: The output end of the overcurrent protection signal setting module is connected to the D trigger, the D end of the D trigger is connected to the overcurrent protection signal, and the Q end is connected to the first upper tube control signal, the second upper tube control signal, the first lower tube control signal and the second lower tube control signal.

10. The driving circuit protection device according to claim 7, characterized in that: The soft shutdown module is connected to the output end of the three-phase motor.

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