Windscreen wiper driving device, windscreen wiper control system and vehicle

Abstract

The invention discloses a windscreen wiper driving device, a windscreen wiper control system and a vehicle. The windscreen wiper driving device comprises a control unit, a first switch tube, a second switch tube and an anti-backflow unit. A controlled end of the first switch tube is connected with a first control signal output end of the control unit, and a first end of the first switch tube is used for being connected with a power supply; the first end of the anti-backflow unit is connected with the second end of the first switch tube, and the second end of the anti-backflow unit is used for being connected with the low-speed driving end of the wiper motor; a controlled end of the second switch tube is connected with a second control signal output end of the control unit, a first end of the second switch tube is used for being connected with a power supply, and a second end of the second switch tube is used for being connected with a high-speed driving end of the wiper motor; wherein the anti-backflow unit is used for preventing current of the high-speed driving end from flowing backwards to the first switch tube from the low-speed driving end when the wiper motor is in a high-speed working state. In this way, the working reliability of the wiper motor can be improved.

Description

Technical Field

[0001] The present application relates to the field of automotive electronic technology, and in particular to a wiper drive device, a wiper control system and a vehicle. Background Art

[0002] The wiper is a key safety component of a car. It can remove raindrops and snowflakes from the windows on snowy or rainy days, and scrape away mud and water splashed onto the windshield when driving on muddy roads, ensuring the driver's line of sight and ensuring the safety of the vehicle.

[0003] The control system of the windshield wiper generally includes a windshield wiper driving device and a windshield wiper motor, wherein the windshield wiper driving device is used to drive the windshield wiper motor to run at high speed or low speed, and the windshield wiper motor is used to drive the windshield wiper to wipe at high speed or low speed.

[0004] If the reliability of the wiper motor can be improved, it will help improve the wiping effect of the wiper, thereby improving the user experience. Summary of the invention

[0005] The main technical problem solved by the present application is to provide a wiper driving device, a wiper control system and a vehicle, which can improve the reliability of the operation of the wiper motor.

[0006] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a wiper drive device, the wiper drive device includes: a control unit; a first switch tube, the controlled end of the first switch tube is connected to the first control signal output end of the control unit, and the first end of the first switch tube is used to connect to a power supply; an anti-backflow unit, the first end of the anti-backflow unit is connected to the second end of the first switch tube, and the second end of the anti-backflow unit is used to connect to the low-speed drive end of the wiper motor; a second switch tube, the controlled end of the second switch tube is connected to the second control signal output end of the control unit, the first end of the second switch tube is used to connect to the power supply, and the second end of the second switch tube is used to connect to the high-speed drive end of the wiper motor; wherein, the anti-backflow unit is used to prevent the current of the high-speed drive end from the low-speed drive end from flowing back to the first switch tube when the wiper motor is in a high-speed working state.

[0007] Optionally, the backflow prevention unit includes a first diode, an anode of the first diode is connected to the drive signal output end of the first switch tube, and a cathode of the first diode is used to be connected to the low-speed drive end.

[0008] Optionally, the wiper drive device also includes a third switch tube, a controlled end of the third switch tube is connected to the third control signal output end of the control unit, a first end of the third switch tube is connected to the second end of the anti-backflow unit, and a second end of the third switch tube is grounded; the control unit is used to control the third switch tube to be turned on in response to obtaining a wiper stop command and a wiper return signal.

[0009] Optionally, the first detection end of the control unit is connected to the first end of the third switch tube, and the second detection end of the control unit is connected to the second end of the second switch tube; the control unit is used to obtain a first voltage corresponding to the first end of the third switch tube and a second voltage corresponding to the second end of the second switch tube; based on the voltage of the power supply, the first voltage and the conduction voltage drop of the anti-backflow unit, the fault state of the first switch tube is determined; based on the voltage of the power supply and the second voltage, the fault state of the second switch tube is determined; based on the first voltage, the fault state of the third switch tube is determined; wherein the fault state of each switch tube includes the presence of an overcurrent fault or the absence of an overcurrent fault; and the control unit is also used to turn off the target switch tube when it is determined that the target switch tube has an overcurrent fault, and the target switch tube is one of the first switch tube, the second switch tube and the third switch tube.

[0010] Optionally, the control unit is further used to perform short circuit fault detection on the wiper motor based on at least the fault state of the first switch tube, the fault state of the second switch tube and the fault state of the third switch tube.

[0011] Optionally, the control unit is used to determine that a short to ground fault exists in the wiper motor in response to an overcurrent fault in the first switch tube or the second switch tube; to determine that a short power fault exists in the wiper motor in response to an overcurrent fault in the third switch tube; or, to determine that a short power fault exists at the low-speed drive end in response to the first drive current being less than or equal to the first current threshold and the third switch tube having an overcurrent fault; to determine that a short power fault exists at the high-speed drive end in response to the first drive current being a negative current and the third switch tube having an overcurrent fault; wherein the first drive current is the drive current flowing through the low-speed drive end.

[0012] Optionally, the wiper drive device also includes a first resistor, a second resistor, a first detection circuit and a second detection circuit; wherein the first end of the first resistor is connected to the second end of the anti-backflow unit, the second end of the first resistor is used to connect to the low-speed drive end, and the first detection circuit is used to detect the voltage across the first resistor; the first end of the second resistor is connected to the second end of the second switch tube, the second end of the second resistor is used to connect to the high-speed drive end, and the second detection circuit is used to detect the voltage across the second resistor; the control unit is used to determine the first drive current flowing through the low-speed drive end based on the voltage across the first resistor, and determine the second drive current flowing through the high-speed drive end based on the voltage across the second resistor; the control unit is also used to control the rain When the wiper motor is in the target working state, in response to the target driving current being less than the first current threshold, it is determined that an open circuit fault exists at the target driving end of the wiper motor; in response to the target driving current being greater than or equal to the second current threshold and less than the third current threshold, it is determined that an overcurrent fault exists at the target driving end; in response to the target driving current being greater than or equal to the third current threshold and less than the fourth current threshold, it is determined that a stall fault exists at the target driving end; wherein, when the target working state is a low-speed working state, the target driving current is the first driving current, and the target driving end is a low-speed driving end; when the target working state is a high-speed working state, the target driving current is the second driving current, and the target driving end is a high-speed driving end.

[0013] Optionally, the wiper drive device also includes a first freewheeling unit and a second freewheeling unit; the first end of the first freewheeling unit is connected to the second end of the anti-backflow unit, and the second end of the first freewheeling unit is grounded; the first end of the second freewheeling unit is connected to the second end of the second switch tube, and the second end of the second freewheeling unit is grounded; the control unit is used to control the first switch tube to be turned off in response to an overcurrent fault or a stall fault at the low-speed drive end; and control the second switch tube to be turned off in response to an overcurrent fault or a stall fault at the high-speed drive end; the first freewheeling unit is used to form a first freewheeling loop with the wiper motor and the ground end at the moment the first switch tube is turned off, and the second freewheeling unit is used to form a second freewheeling loop with the wiper motor and the ground end at the moment the second switch tube is turned off.

[0014] Optionally, the first freewheeling unit includes a second diode, a cathode of the second diode is connected to the second end of the backflow prevention unit, and an anode of the second diode is grounded.

[0015] Optionally, the first freewheeling unit also includes a third switch tube, and the second diode is the body diode of the third switch tube; the controlled end of the third switch tube is connected to the third control signal output end of the control unit, the first end of the third switch tube is connected to the second end of the anti-backflow unit, and the second end of the third switch tube is grounded; the control unit is also used to control the third switch tube to turn on after executing the step of controlling the first switch tube to turn off.

[0016] Optionally, the second freewheeling unit includes a third diode, a cathode of the third diode is connected to the second end of the second switch tube, and an anode of the third diode is grounded.

[0017] In order to solve the above technical problems, another technical solution adopted in the present application is: to provide a wiper control system, which includes a wiper motor and the aforementioned wiper driving device.

[0018] In order to solve the above technical problems, another technical solution adopted in the present application is: providing a vehicle, which includes the aforementioned wiper control system.

[0019] In the above scheme, the wiper drive device includes a control unit, a first switch tube, a second switch tube and an anti-backflow unit, wherein the first end of the anti-backflow unit is connected to the second end of the first switch tube, and the second end of the anti-backflow unit is used to connect to the low-speed drive end of the wiper motor. When the control unit controls the wiper motor to be in a high-speed working state, the anti-backflow unit can prevent the current of the high-speed drive end from backflowing from the low-speed drive end to the first switch tube, thereby avoiding the reduction of the wiper motor speed due to the backflow of current, and improving the reliability of the wiper motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a structural schematic diagram of an embodiment of a wiper driving device provided by the present application;

[0021] Figure 2 is a structural schematic diagram of another embodiment of the wiper driving device provided by the present application;

[0022] Figure 3 is a structural schematic diagram of another embodiment of the wiper driving device provided by the present application;

[0023] Figure 4 is a structural schematic diagram of another embodiment of the wiper driving device provided by the present application;

[0024] Figure 5 It is a structural schematic diagram of an embodiment of a wiper control system provided by the present application;

[0025] Figure 6 It is a flowchart of an embodiment of a fault diagnosis method provided by the present application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail below with reference to the accompanying drawings and examples.

[0027] It should be noted that the terms "first", "second", etc. in this article are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence; the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0028] The wiper motor includes a high-speed driving end and a low-speed driving end. Currently, the wiper driving device usually includes two driving circuits respectively connected to the low-speed driving end and the high-speed driving end of the wiper motor to drive the wiper motor in a low-speed working state or a high-speed working state respectively.

[0029] See also Figure 1 , Figure 1 It is a structural schematic diagram of an embodiment of a wiper drive device provided by the present application. The wiper drive device includes a controller, a first drive circuit and a second drive circuit. Among them, the control signal input end of the first drive circuit and the control signal input end of the second drive circuit are connected to the controller, the drive signal output end of the first drive circuit is used to connect to the low-speed drive end of the wiper motor, and the drive signal output end of the second drive circuit is used to connect to the high-speed drive end of the wiper motor. Specifically, the first drive circuit and the second drive circuit are both half-bridge drive circuits.

[0030] The controller is used to output a control signal to the first drive circuit, and the first drive circuit is used to output a drive signal to the low-speed drive end of the wiper motor to drive the wiper motor to a low-speed working state, thereby driving the wiper to wipe at a low speed. Alternatively, the controller is used to output a control signal to the second drive circuit, and the second drive circuit is used to output a drive signal to the high-speed drive end of the wiper motor to drive the wiper motor to a high-speed working state, thereby driving the wiper to wipe at a high speed.

[0031] However, in the above-mentioned wiper driving device, the first driving circuit and the second driving circuit seem to be independent, but due to the particularity of the wiper motor, the motor coils inside the wiper motor are connected to each other. When the wiper motor is in a high-speed working state, a part of the current at the high-speed driving end of the wiper motor will flow back from the low-speed wiper end of the wiper motor. The backflow current passes through the body diode ( Figure 1 The windshield wiper motor (not shown) forms a loop to the power supply end, thereby losing part of the current and reducing the speed of the wiper motor when it is working at a high speed, resulting in a lower high-speed wiping speed of the wiper, which in turn affects the wiping effect of the wiper.

[0032] See also Figure 2 , Figure 2Schematic diagram of another embodiment of the wiper drive device provided by the present application. Figure 2 As shown, the wiper driving device includes a control unit 10 , a first switch tube 21 , a second switch tube 22 and a backflow prevention unit 30 .

[0033] The control unit 10 includes a first control signal output terminal and a second control signal output terminal. The first control signal output terminal of the control unit 10 is used to output a first control signal, and the second control signal output terminal is used to output a second control signal.

[0034] The controlled end of the first switch tube 21 is connected to the first control signal output end of the control unit 10, and the first end of the first switch tube 21 is used to connect to the power supply (i.e. Figure 2 The first switch tube 21 is connected to the VBAT in the control unit 10, and the second end of the first switch tube 21 is connected to the low-speed driving end of the wiper motor. The first switch tube 21 is used to drive the wiper motor to a low-speed working state under the control of the first control signal of the control unit 10.

[0035] The controlled end of the second switch tube 22 is connected to the second control signal output end of the control unit 10, and the first end of the second switch tube 22 is used to connect to the power supply (i.e. Figure 2 The second end of the second switch tube 22 is connected to the VBAT in the control unit 10, and the second end of the second switch tube 22 is connected to the high-speed driving end of the wiper motor. The second switch tube 22 is used to drive the wiper motor to a high-speed working state under the control of the second control signal of the control unit 10.

[0036] Exemplarily, both the first switch tube 21 and the second switch tube 22 are NMOS tubes. At this time, the controlled end of the first switch tube 21, the first end of the first switch tube 21 and the second end of the first switch tube 21 are respectively the gate, drain and source of the first switch tube 21, and the controlled end of the second switch tube 22, the first end of the second switch tube 22 and the second end of the second switch tube 22 are respectively the gate, drain and source of the second switch tube 22. Since the stall current of the wiper motor is relatively large, in order to avoid burning the first switch tube 21 and the second switch tube 22, a MOS tube with small internal resistance and strong driving ability can be selected according to actual needs.

[0037] Exemplarily, the operating voltage of the power supply VBAT is between 9V and 16V, for example, the voltage of the power supply VBAT is 13.5V.

[0038] Since the first switch tube 21 has a body diode ( Figure 2(not shown in the figure), when the wiper motor is in a high-speed working state, a part of the current will flow back from the low-speed wiper end of the wiper motor to the high-speed driving end of the wiper motor, and the backflow current will pass through the body diode of the first switch tube 21 to the power supply VBAT to form a loop. For this reason, the present application adds an anti-backflow unit 30, the first end of the anti-backflow unit 30 is connected to the second end of the first switch tube 21, and the second end of the anti-backflow unit 30 is used to connect to the low-speed driving end of the wiper motor. The anti-backflow unit 30 is used to prevent the current at the high-speed driving end from flowing back from the low-speed driving end to the first switch tube 21 when the wiper motor is in a high-speed working state.

[0039] In this embodiment, the wiper drive device includes a control unit, a first switch tube, a second switch tube and an anti-backflow unit, wherein the first end of the anti-backflow unit is connected to the second end of the first switch tube, and the second end of the anti-backflow unit is used to be connected to the low-speed drive end of the wiper motor. When the control unit controls the wiper motor to be in a high-speed working state, the anti-backflow unit can prevent the current of the high-speed drive end from backflowing from the low-speed drive end to the first switch tube, thereby avoiding the reduction of the speed of the wiper motor due to the backflow of current, and improving the reliability of the operation of the wiper motor.

[0040] See also Figure 3 , Figure 3 FIG. 1 is a schematic diagram of the structure of another embodiment of the wiper drive device provided by the present application. Figure 3 As shown, the anti-backflow unit 30 includes a first diode 31. The anode of the first diode 31 is connected to the drive signal output end of the first switch tube 21, and the cathode of the first diode 31 is used to connect to the low-speed drive end of the wiper motor. The first diode 31 is used to prevent the current of the high-speed drive end from backflowing from the low-speed drive end to the first switch tube 21 when the wiper motor is in a high-speed working state, so as to avoid the speed of the wiper motor from decreasing due to the backflow of current, thereby improving the reliability of the wiper motor.

[0041] Please refer again Figure 3 The wiper driving device further includes a first resistor 41 , a second resistor 42 , a first detection circuit 43 and a second detection circuit 44 .

[0042] Specifically, the first end of the first resistor 41 is connected to the second end of the anti-backflow unit 30, the second end of the first resistor 41 is used to connect to the low-speed drive end, the first detection circuit 43 is used to detect the voltage across the first resistor 41, and the signal output end of the first detection circuit 43 is connected to the first sampling port of the control unit 10 ( Figure 3 The first end of the second resistor 42 is connected to the second end of the second switch tube 22, the second end of the second resistor 42 is used to connect to the high-speed drive end, the second detection circuit 44 is used to detect the voltage across the second resistor 42, and the signal output end of the second detection circuit 44 is connected to the second sampling port of the control unit 10 ( Figure 3For example, the resistance of the first resistor 41 and the resistance of the second resistor 42 are both in the milliohm level, and the first resistor 41 and the second resistor 42 can be selected according to actual needs.

[0043] The control unit 10 is used to obtain the voltage across the first resistor 41; determine the first drive current flowing through the low-speed drive end based on the voltage across the first resistor 41; and determine the second drive current flowing through the high-speed drive end based on the voltage across the second resistor 42.

[0044] The control unit 10 is also used to determine that there is an open circuit fault at the target drive end of the wiper motor in response to the target drive current being less than a first current threshold when controlling the wiper motor to be in a target working state; to determine that there is an overcurrent fault at the target drive end in response to the target drive current being greater than or equal to the second current threshold and less than a third current threshold; and to determine that there is a stall fault at the target drive end in response to the target drive current being greater than or equal to the third current threshold and less than a fourth current threshold.

[0045] Among them, when the target working state is a low-speed working state, the target driving current is a first driving current, and the target driving end is a low-speed driving end; when the target working state is a high-speed working state, the target driving current is a second driving current, and the target driving end is a high-speed driving end.

[0046] The value of the first current threshold is close to 0, the second current threshold is greater than the first current threshold and less than the third current threshold, the third current threshold is less than the fourth current threshold, and the first current threshold, the second current threshold, the third current threshold and the fourth current threshold are set according to actual needs. For example, the first current threshold is 500mA, the second current threshold is 12A, the third current threshold is 18A, and the fourth current threshold is 40A.

[0047] During the actual operation of the wiper motor, the drive circuit of the low-speed drive end or the high-speed drive end of the wiper motor may be disconnected, resulting in an open circuit fault; when the wiper motor is subject to greater resistance or the working environment temperature is low, the drive current of the low-speed drive end or the high-speed drive end of the wiper motor is large, resulting in an overcurrent fault; in severe weather, such as snow and ice in winter, because the wiper is frozen, starting the wiper motor at this time will cause the drive current of the low-speed drive end or the high-speed drive end of the wiper motor to be large, resulting in a stall fault. By obtaining the first drive current of the low-speed drive end of the wiper motor and the second drive current of the high-speed drive end, and detecting the open circuit fault, overcurrent fault and stall fault of the wiper motor based on the first drive current and the second drive current, the reliability and safety of the wiper motor can be further improved.

[0048] Furthermore, the control unit 10 is also used to control the first switch tube 21 to be turned off in response to an overcurrent fault or a stall fault at the low-speed driving end of the wiper motor; and to control the second switch tube 22 to be turned off in response to an overcurrent fault or a stall fault at the high-speed driving end of the wiper motor.

[0049] When an overcurrent fault or a stall fault occurs at the low-speed driving end of the wiper motor, the first switch tube 21 is controlled to be turned off, and when an overcurrent fault or a stall fault occurs at the high-speed driving end, the second switch tube 22 is controlled to be turned off, which can further improve the reliability of the wiper motor.

[0050] Please refer again Figure 3 Considering that at the moment when the first switch tube 21 or the second switch tube 22 is turned off, the coil of the wiper motor will have a large reverse electromotive force and a large current, in order to ensure the safety of the entire circuit, the wiper drive device also includes a first freewheeling unit 50 and a second freewheeling unit 60, and the first freewheeling unit 50 and the second freewheeling unit 60 are both used for energy discharge.

[0051] Specifically, the first end of the first freewheeling unit 50 is connected to the second end of the backflow prevention unit 30, and the second end of the first freewheeling unit 50 is grounded. The first freewheeling unit 50 is used to form a first freewheeling loop with the wiper motor and the grounding end when the first switch tube 21 is turned off.

[0052] In one embodiment, the first freewheeling unit 50 includes a second diode 51, and the second diode 51 is an additionally provided diode. The cathode of the second diode 51 is connected to the second end of the anti-backflow unit 30, and the anode of the second diode 51 is grounded. The current generated at the moment of the first switch tube 21 being turned off passes through the anode of the second diode 51, the cathode of the second diode 51, the wiper motor and the grounding end to form a first freewheeling loop, thereby discharging energy.

[0053] In another embodiment, the second freewheeling unit 60 includes a third switch tube 23 and a second diode 51, and the second diode 51 is a body diode of the third switch tube 23. The controlled end of the third switch tube 23 is connected to the third control signal output end of the control unit 10, the first end of the third switch tube 23 is connected to the second end of the anti-backflow unit 30, and the second end of the third switch tube 23 is grounded. Exemplarily, the third diode 61 is an NMOS tube.

[0054] The control unit 10 is further configured to control the third switch tube 23 to be turned on after executing the step of controlling the first switch tube 21 to be turned off. For example, the third switch tube 23 may be controlled to be turned on only for a first preset time length, and the first preset time length is a smaller value, that is, the third switch tube 23 is controlled to be turned on for a short period of time. The specific value of the first preset time length may be set according to actual needs.

[0055] In this embodiment, in addition to energy discharge through the second diode 51 , the third switch tube 23 may be turned on briefly to enhance the energy discharge capability.

[0056] Specifically, the first end of the second freewheeling unit 60 is connected to the second end of the second switch tube 22, and the second end of the second freewheeling unit 60 is grounded. The second freewheeling unit 60 is used to form a second freewheeling loop with the wiper motor and the ground end when the second switch tube 22 is turned off.

[0057] In one embodiment, the second freewheeling unit 60 includes a fourth switch tube (not shown in the figure) and a third diode 61, and the third diode 61 is a body diode of the fourth switch tube. The controlled end of the fourth switch tube is connected to the fourth control signal output end of the control unit 10, the first end of the fourth switch tube is connected to the second end of the second switch tube 22, and the second end of the fourth switch tube is grounded. The cathode of the third diode 61 is connected to the second end of the second switch tube 22, and the anode of the third diode 61 is grounded. Exemplarily, the fourth switch tube is an NMOS tube.

[0058] The control unit 10 is further configured to control the fourth switch tube to be turned on after executing the step of controlling the second switch tube 22 to be turned off. For example, the fourth switch tube may be controlled to be turned on only for a second preset time length, and the second preset time length is a smaller value, that is, the fourth switch tube is controlled to be turned on for a short period of time. The specific value of the second preset time length can be set according to actual needs.

[0059] In this embodiment, the current generated when the second switch tube 22 is turned off instantly passes through the anode of the third diode 61, the cathode of the second diode 51, the wiper motor and the ground terminal to form a second freewheeling loop, thereby discharging energy. In addition to discharging energy through the third diode 61, the fourth switch tube can also be turned on briefly to enhance the energy discharging capability.

[0060] In another embodiment, the second freewheeling unit 60 may include only a third diode 61, which is an additionally arranged diode. Compared with the method of using a fourth switch tube and a body diode of the fourth switch tube, using only the third diode 61 can reduce the hardware cost of the wiper drive device.

[0061] See also Figure 4 , Figure 4 FIG. 1 is a schematic diagram of the structure of another embodiment of the wiper drive device provided by the present application. Figure 4As shown, the wiper drive device further includes a third switch tube 23. The controlled end of the third switch tube 23 is connected to the third control signal output end of the control unit 10, the first end of the third switch tube 23 is connected to the second end of the anti-backflow unit 30, and the second end of the third switch tube 23 is grounded. In addition, the control unit 10 is also connected to the return signal detection end of the wiper motor. When the wiper returns to the initial position, the return signal detection end will output a wiper return signal to the control unit 10. Exemplarily, the wiper return signal is a low level.

[0062] The control unit 10 is further configured to control the third switch tube 23 to be turned on in response to obtaining a wiper stop instruction and a wiper return signal.

[0063] In this embodiment, the gear positions of the wiper include three gear positions: OFF gear, low speed gear and high speed gear. When the wiper motor is controlled to stop working, the wiper is in OFF gear; when the wiper motor is controlled to be in a low speed working state, the wiper motor is in a low speed gear; when the wiper motor is controlled to be in a high speed working state, the wiper motor is in a high speed gear. In addition, in this embodiment, the wiper is set to switch from OFF gear to high speed gear in the order of "OFF gear-low speed gear-high speed gear", instead of switching directly from OFF gear to high speed gear, and the wiper is set to switch from high speed gear to OFF gear in the order of "high speed gear-low speed gear-OFF gear", instead of switching directly from high speed gear to OFF gear. Regardless of whether the wiper is currently in low speed gear or high speed gear, it will eventually switch to OFF gear through low speed gear.

[0064] In one embodiment, a mechanical knob switch for wipers is provided on the vehicle, and the user can switch the gear of the wipers by rotating the mechanical knob switch. In this embodiment, when it is detected that the mechanical knob switch is switched from the low gear to the OFF gear, it is confirmed that the wiper stop instruction is obtained.

[0065] In another embodiment, the wiper's OFF gear, low speed gear, and high speed gear are respectively designed with corresponding gear switches. Exemplarily, the three gear switches can be hardware switches or software switches displayed on the display interface of the terminal device, and the user clicks each gear switch to control the gear of the wiper. In this embodiment, when it is detected that the user clicks the gear switch corresponding to the OFF gear, it is confirmed that the wiper stop instruction is obtained.

[0066] In another embodiment, the user can control the windshield wiper position by voice. In this embodiment, when the user's target voice is detected, it is confirmed that the windshield wiper stop instruction is obtained. For example, the target voice can be "turn off the windshield wiper".

[0067] In another embodiment, a rain sensor is also installed on the vehicle, and the control unit 10 is also used to obtain a detection signal from the rain sensor to determine the amount of rain on the front windshield. When the rain is detected to be less than a preset rain threshold, it is determined that the wipers are no longer needed for wiping, and it can be confirmed that a wiper stop command has been obtained.

[0068] Further, after the wiper stop command is obtained, it is continued to detect whether the wiper return signal is obtained. When the wiper return signal is obtained, the third switch tube 23 is controlled to be turned on. Exemplarily, the third switch tube 23 can be controlled to be turned on only for a third preset time length, and the third preset time length is a smaller value, that is, the third switch tube 23 is controlled to be turned on for a short period of time. The specific value of the third preset time length can be set according to actual needs.

[0069] Since the wiper motor has rotational inertia, even if the wiper motor stops driving, the wiper motor will still rotate to a certain angle due to inertia, and due to the different friction caused by the different wetness of the front windshield, the wiper stops at different positions each time. If the wiper stops on the front windshield, it will block the driver's sight and affect driving safety; if the wiper motor has a large rotational inertia, it may cause the wiper to hit the front insurance, which may cause damage to the wiper. Therefore, in this embodiment, in order to ensure that the wiper can stop within the specified range every time after wiping, the wiper is designed to switch from the low speed gear to the OFF gear and detect the wiper return signal, and control the third switch tube 23 of the low speed drive end of the wiper motor to conduct, so that the low speed drive end of the wiper motor, the third switch tube 23 and the grounding end can form a discharge circuit, thereby discharging the excess energy of the low speed drive end of the wiper motor, so that there is no excess energy to maintain the rotational inertia of the wiper motor, thereby achieving precise braking and precise return of the wiper.

[0070] Please refer again Figure 4 , the control unit 10 includes a controller 11 and a gate driver 12. Among them, the controller 11 and the gate driver 12 are connected, such as the controller 11 and the gate driver 12 are connected through an SPI (Serial Peripheral Interface). Exemplarily, the controller 11 is an MCU (Microcontroller Unit, micro control unit 10). Exemplarily, the gate driver 12 is an intelligent half-bridge gate driver 12. The gate driver 12 includes a first control signal output terminal, a second control signal output terminal and a third control signal output terminal, and the first control signal output terminal, the second control signal output terminal and the third control signal output terminal of the gate driver 12 are respectively connected to the controlled end of the first switch tube 21, the controlled end of the second switch tube 22 and the controlled end of the third switch tube 23.

[0071] Please refer again Figure 4The control unit 10 further includes a first detection end and a second detection end, the first detection end of the control unit 10 is connected to the first end of the third switch tube 23, and the second detection end of the control unit 10 is connected to the second end of the second switch tube 22. Specifically, the gate driver 12 in the control unit 10 has a fault diagnosis function, the gate driver 12 includes a first detection end and a second detection end, the first detection end of the gate driver 12 is connected to the first end of the third switch tube 23, and the second detection end of the gate driver 12 is connected to the second end of the second switch tube 22.

[0072] The control unit 10 is used to obtain a first voltage corresponding to the first end of the third switch tube 23 and a second voltage corresponding to the second end of the second switch tube 22; based on the power supply (ie Figure 4 The control unit 10 determines the fault state of the first switch tube 21 based on the voltage of VBAT in the power supply, the first voltage and the conduction voltage drop of the anti-backflow unit 30; determines the fault state of the second switch tube 22 based on the voltage of the power supply and the second voltage; and determines the fault state of the third switch tube 23 based on the first voltage corresponding to the first end of the third switch tube 23. Among them, the fault state of each switch tube includes the presence of an overcurrent fault or the absence of an overcurrent fault. Further, the control unit 10 is also used to control the target switch tube to turn off when it is determined that the target switch tube has an overcurrent fault. The target switch tube is one of the first switch tube 21, the second switch tube 22 and the third switch tube 23.

[0073] Specifically, when the wiper motor is driven in a low-speed working state, the first switch tube 21 is configured to be in a conducting state. At this time, the gate driver 12 is used to obtain a first voltage; based on the voltage of the power supply, the first voltage and the conduction voltage drop of the anti-backflow unit 30, the voltage drop of the first switch tube 21 is determined, specifically, the voltage of the power supply is subtracted from the first voltage, and the conduction voltage drop of the anti-backflow unit 30 is subtracted to obtain the voltage drop of the first switch tube 21; based on the voltage drop of the first switch tube 21 and the conduction resistance of the first switch tube 21, the current flowing through the first switch tube 21 is determined; based on the current flowing through the first switch tube 21, it is determined whether the first switch tube 21 has an overcurrent fault. When the current flowing through the first switch tube 21 is greater than or equal to the set current threshold, the gate driver 12 determines that the first switch tube 21 has an overcurrent fault and controls the first switch tube 21 to be disconnected; otherwise, it is determined that the first switch tube 21 does not have an overcurrent fault.

[0074] Specifically, when the wiper motor is driven in a high-speed working state, the second switch tube 22 is configured to be in a conducting state. At this time, the gate driver 12 is used to obtain the second voltage; based on the voltage of the power supply and the second voltage, the voltage drop of the second switch tube 22 is determined, and the voltage drop of the second switch tube 22 is obtained by subtracting the second voltage from the voltage of the power supply; based on the voltage drop of the second switch tube 22 and the on-resistance of the second switch tube 22, the current flowing through the second switch tube 22 is determined; based on the current flowing through the second switch tube 22, it is determined whether the second switch tube 22 has an overcurrent fault. When the current flowing through the second switch tube 22 is greater than the set current threshold, the gate driver 12 determines that the second switch tube 22 has an overcurrent fault and controls the second switch tube 22 to be disconnected; otherwise, it is determined that the second switch tube 22 does not have an overcurrent fault.

[0075] Specifically, when the wiper is switched from the low gear to the OFF gear, the third switch tube 23 is configured to be in the on state. At this time, the gate driver 12 is used to obtain the first voltage; based on the first voltage and the on-resistance of the third switch tube 23, the current flowing through the third switch tube 23 is determined; based on the current flowing through the third switch tube 23, whether the third switch tube 23 has an overcurrent fault is determined. When the current flowing through the third switch tube 23 is greater than the set current threshold, the gate driver 12 determines that the third switch tube 23 has an overcurrent fault and controls the third switch tube 23 to be disconnected; otherwise, it is determined that the third switch tube 23 does not have an overcurrent fault.

[0076] When a short circuit occurs in the wiper motor, a large current will flow through the first switch tube 21, the second switch tube 22 or the third switch tube 23. By performing overcurrent detection on the first switch tube 21, the second switch tube 22 or the third switch tube 23, when it is determined that the first switch tube 21, the second switch tube 22 or the third switch tube 23 has an overcurrent fault, the faulty switch tube is controlled to be disconnected, so that the faulty switch tube can be protected from being damaged by the large current.

[0077] Furthermore, in this embodiment, it is considered that in actual scenarios, the wiper motor may have a short-to-ground fault or a short-to-power fault. For example, during the driving of the vehicle, the wiper is wiping, but the wiper motor abnormally infiltrates water, causing a short-to-ground fault at the low-speed drive end or the high-speed drive end of the wiper motor. For another example, due to aging and damage of the wiring harness, a short-to-ground fault or a short-to-power fault occurs at the low-speed drive end or the high-speed drive end of the wiper motor. Therefore, in this embodiment, short-circuit fault detection is also performed on the wiper motor to further improve the reliability of the wiper motor.

[0078] In this embodiment, the control unit 10 is used to perform short circuit fault detection on the wiper motor based on at least the fault state of the first switch tube 21 , the fault state of the second switch tube 22 , and the fault state of the third switch tube 23 .

[0079] Specifically, the gate driver 12 in the control unit 10 is used to feed back switch tube fault data to the controller 11, and the switch tube fault data is used to reflect the fault status of the first switch tube 21, the second switch tube 22, and the third switch tube 23. After the controller 11 obtains the switch tube fault data fed back by the gate driver 12, it parses the fault data, and determines the fault status of the first switch tube 21, the second switch tube 22, and the third switch tube 23 based on the parsed switch tube fault data.

[0080] In one implementation, the controller 11 can determine whether there is a short-to-ground fault in the wiper motor according to the fault state of the first switch tube 21 or the second switch tube 22 .

[0081] When the wiper motor is in a low-speed working state and there is a short-to-ground fault at the low-speed driving end of the wiper motor, or when the wiper motor is in a low-speed working state and there is a short-to-ground fault at the high-speed driving end of the wiper motor, the current flowing through the first switch tube 21 is relatively large. At this time, the gate driver 12 will determine that there is an overcurrent fault in the first switch tube 21, thereby turning off the first switch tube 21. Therefore, the controller 11 can be used to determine that there is a short-to-ground fault at the low-speed driving end or the high-speed driving end when it is determined that there is an overcurrent fault in the first switch tube 21.

[0082] When the wiper motor is in a high-speed working state and there is a short-to-ground fault at the low-speed driving end of the wiper motor, or when the wiper motor is in a high-speed working state and there is a short-to-ground fault at the high-speed driving end of the wiper motor, the current flowing through the second switch tube 22 is relatively large. At this time, the gate driver 12 will determine that there is an overcurrent fault at the second switch tube 22, thereby turning off the second switch tube 22. Therefore, the controller 11 can be used to determine that there is a short-to-ground fault at the low-speed driving end or the high-speed driving end when the wiper motor is in a high-speed working state when determining that there is an overcurrent fault at the second switch tube 22.

[0083] Based on the above analysis, the controller 11 may be used to determine that a short-to-ground fault exists in the wiper motor in response to an overcurrent fault in the first switch tube 21 or the second switch tube 22 .

[0084] In one implementation, the controller 11 may determine whether the wiper motor has a short power fault based on the fault state of the third switch tube 23 .

[0085] When the wiper motor is in a low-speed working state and there is a short power fault at the low-speed driving end of the wiper motor, the first switch tube 21, the anti-backflow unit 30 and the first resistor 41 are short-circuited, and the first drive current obtained by the controller 11 is close to 0. Further, when switching from the low-speed gear to the OFF gear, the third switch tube 23 will be configured to be in a conducting state for precise braking of the wiper. Due to the short power fault at the low-speed driving end, the current flowing through the third switch tube 23 is large. At this time, the gate driver 12 will determine that the third switch tube 23 has an overcurrent fault, thereby turning off the third switch tube 23. Therefore, in this case, it can be determined whether the wiper motor has a short power fault based only on the fault state of the third switch tube 23; or, combined with the magnitude of the first drive current and the fault state of the third switch tube 23, it can be determined whether there is a short power fault at the low-speed driving end of the wiper motor.

[0086] When the wiper motor is in a low-speed working state and there is a short power fault at the high-speed driving end of the wiper motor, the first switch tube 21, the anti-backflow unit 30 and the first resistor 41 are short-circuited, and part of the current will flow from the high-speed driving end to the low-speed driving end, causing the first driving current obtained by the controller 11 to drop to a negative current. It should be noted that when the wiper motor is normally driven in a low-speed working state and there is no short power fault at the high-speed driving end of the wiper motor, the first driving current flows into the low-speed driving end of the wiper motor through the first resistor, and the first driving current is a positive current. Further, when switching from the low-speed gear to the OFF gear, the third switch tube 23 will be configured to be in the on state for precise braking of the wiper. Due to the short power fault at the high-speed driving end, the current flowing through the third switch tube 23 is large. At this time, the gate driver 12 will determine that the third switch tube 23 has an overcurrent fault, thereby turning off the third switch tube 23. Therefore, in this case, it is possible to determine whether there is a short power fault in the wiper motor based only on the fault state of the third switch tube 23; or, based on the size of the first drive current and the fault state of the third switch tube 23, it is possible to determine whether there is a short power fault at the high-speed drive end of the wiper motor.

[0087] In the case where the wiper motor is in a high-speed working state and there is a short power fault at the low-speed driving end of the wiper motor, or in the case where the wiper motor is in a high-speed working state and there is a short power fault at the high-speed driving end of the wiper motor, the controller 11 cannot determine whether there is a short power fault at the low-speed driving end and the high-speed driving end by obtaining the second driving current. Considering that when switching from the low-speed gear to the OFF gear, the third switch tube 23 will be configured to be in a conducting state for precise braking of the wiper, therefore, if the wiper motor is in a high-speed working state and there is a short circuit fault at the low-speed driving end of the wiper motor, or in the case where the wiper motor is in a high-speed working state and there is a short power fault at the high-speed driving end of the wiper motor, the short power fault at the low-speed driving end or the high-speed driving end can be detected when switching from the low-speed gear to the OFF gear for braking. The detection principle is the same as the above two situations and will not be repeated here.

[0088] Based on the above analysis, the controller 11 can be used to determine that the wiper motor has a short power supply fault in response to the third switch tube 23 having an overcurrent fault. Alternatively, the controller 11 can also be used to determine that the low-speed drive end of the wiper motor has a short power supply fault in response to the first drive current being less than or equal to the first current threshold and the third switch tube 23 having an overcurrent fault; in response to the first drive current being a negative current and the third switch tube 23 having an overcurrent fault, determine that the high-speed drive end of the wiper motor has a short power supply fault. The value of the first current threshold is close to 0, for example, the first current threshold is 500mA.

[0089] It should be noted that a short-to-ground fault refers to a short circuit with the ground terminal, and a short-to-power fault refers to a short circuit with the power supply.

[0090] In the present embodiment, a comprehensive improvement is made to address the problems of imperfect design performance and inadequate protective measures of the existing wiper drive device: by providing an anti-backflow unit, the current at the high-speed drive end can be prevented from backflowing from the low-speed drive end to the first switch tube when the wiper motor is in a high-speed working state, thereby improving the wiping effect of the wiper; the discrete first switch tube and the second switch tube are used to respectively drive the low-speed drive end and the high-speed drive end of the wiper motor, which is more cost-effective than using an integrated drive chip; by providing a third switch tube, it can be ensured that the wiper stops in place every time, thereby achieving precise braking of the wiper; by providing a gate driver, the fault status of the first switch tube, the second switch tube and the third switch tube can be detected in real time, and when an overcurrent fault occurs in the first switch tube, the second switch tube or the third switch tube, the faulty switch tube can be turned off in time to protect the switch tube from being driven by a large current. Damage; by setting the first freewheeling unit and the second freewheeling unit, energy can be discharged to protect the safety of the entire circuit when an overcurrent fault or a stall fault occurs in the wiper motor; by obtaining the first drive current flowing through the low-speed drive end of the wiper motor, the second drive current flowing through the high-speed drive end of the wiper motor, the fault state of the first switch tube, the fault state of the second switch tube, and the fault state of the third switch tube, various faults of the wiper motor (including open circuit fault, overcurrent fault, stall fault, short ground fault, and short power fault) can be diagnosed, which greatly improves the safety and reliability of the wiper motor; the wiper drive device can be integrated into the vehicle body controller, and the controller in the control unit can be the main controller of the body controller, and the main controller of the body controller can realize the control of the wiper motor, which realizes the integration of the controller to the greatest extent and reduces the hardware cost. Therefore, the wiper drive device in this embodiment has low cost, high performance, high safety, and high reliability.

[0091] See also Figure 5 , Figure 5 Schematic diagram of the structure of an embodiment of a wiper control system provided by the present application. Figure 5 As shown in FIG. 1 , the wiper control system includes a wiper motor and a wiper drive device. The wiper drive device may be Figures 2 to 4 Any of the wiper drive arrangements shown.

[0092] This embodiment also provides a vehicle, which may include Figure 5 Wiper control system shown.

[0093] See also Figure 6 , Figure 6 is a flow chart of an embodiment of a fault diagnosis method provided by the present application. The method can be applied to Figure 4 The wiper drive device shown in the figure, and the method can Figure 4The controller in the embodiment is used to implement fault diagnosis of the wiper motor. It should be noted that if there is substantially the same result, the method of the present application is not limited to Figure 6 The process sequence shown is limited.

[0094] like Figure 6 As shown, the method comprises the following steps:

[0095] S61: Acquire a first drive current flowing through a low-speed drive end of the wiper motor, a second drive current flowing through a high-speed drive end of the wiper motor, and switch tube fault data fed back by a gate driver.

[0096] For details about the first drive current and the second drive current, see Figure 3 The relevant descriptions in the illustrated embodiments are omitted here in detail.

[0097] The switch tube fault data is used to reflect the fault status of the first switch tube, the second switch tube, and the third switch tube. For information about obtaining the switch tube fault data, refer to Figure 4 The relevant descriptions in the illustrated embodiments are omitted here in detail.

[0098] In one embodiment, the wiper drive device is integrated in the body controller. When it is detected that the body controller is powered on and the wiper switch is in the on state, it is determined that the wiper motor starts working. At this time, the first drive current, the second drive current and the switch tube fault data are obtained.

[0099] S62: Perform fault diagnosis on the wiper motor based on the first drive current, the second drive current and the switch tube fault data.

[0100] In one embodiment, the fault diagnosis of the wiper motor includes the following sub-steps:

[0101] Sub-step one: determine whether there is a short-to-ground fault in the wiper motor.

[0102] If the wiper motor has a short-to-ground fault, execute sub-step 2. If the wiper motor does not have a short-to-ground fault, execute sub-step 3.

[0103] Specifically, the gate driver turns off the first switch tube when determining that the first switch tube has an overcurrent fault, and turns off the second switch tube when determining that the second switch tube has an overcurrent fault, so as to timely protect the first switch tube and the second switch tube from being burned by high current.

[0104] When the controller determines that the first switch tube has an overcurrent fault or the second switch tube has an overcurrent fault based on the switch tube fault data fed back by the gate driver, it determines that the wiper motor has a short-to-ground fault. Specifically, when the controller determines that the first switch tube has an overcurrent fault, it determines that the low-speed drive end or the high-speed drive end has a short-to-ground fault when the wiper motor is in a low-speed working state; when the controller determines that the second switch tube has an overcurrent fault, it determines that the low-speed drive end or the high-speed drive end has a short-to-ground fault when the wiper motor is in a high-speed working state.

[0105] Sub-step two: reporting a short-to-ground fault in the wiper motor.

[0106] Sub-step three: determine whether the wiper motor has an overcurrent fault.

[0107] If the wiper motor has an overcurrent fault, execute sub-step 4. If the wiper motor does not have an overcurrent fault, execute sub-step 5.

[0108] Specifically, when the wiper motor is in a low-speed operating state, if the controller determines that the first drive current is greater than or equal to the second current threshold and less than the third current threshold, it is determined that an overcurrent fault exists at the low-speed drive end of the wiper motor; when the wiper motor is in a high-speed operating state, if the controller determines that the second drive current is greater than or equal to the second current threshold and less than the third current threshold, it is determined that an overcurrent fault exists at the high-speed drive end of the wiper motor.

[0109] Sub-step four: controlling the first switch tube or the second switch tube to turn off, and reporting that the wiper motor has an overcurrent fault.

[0110] Specifically, when it is determined that there is an overcurrent fault at the low-speed drive end of the wiper motor, a control instruction is sent to the gate driver, the gate driver controls the first switch tube to turn off to protect the first switch tube, and reports that there is an overcurrent fault at the low-speed drive end of the wiper motor. When it is determined that there is an overcurrent fault at the high-speed drive end of the wiper motor, a control instruction is sent to the gate driver, the gate driver controls the second switch tube to turn off to protect the second switch tube, and reports that there is an overcurrent fault at the high-speed drive end of the wiper motor.

[0111] Sub-step five: determine whether the wiper motor has a stall fault.

[0112] If the wiper motor has a stall fault, execute sub-step 6. If the wiper motor does not have a stall fault, execute sub-step 7.

[0113] Specifically, when the wiper motor is in a low-speed working state, if the controller determines that the first drive current is greater than or equal to the third current threshold and less than the fourth current threshold, it is determined that the first drive end has a stall fault. When the wiper motor is in a high-speed working state, if the controller determines that the second drive current is greater than or equal to the third current threshold and less than the fourth current threshold, it is determined that the high-speed drive end of the wiper motor has a stall fault.

[0114] Sub-step six: controlling the first switch tube or the second switch tube to turn off, and reporting that the wiper motor has a stall fault.

[0115] Specifically, when it is determined that there is a stall fault at the low-speed drive end of the wiper motor, a control instruction is sent to the gate driver, the gate driver controls the first switch tube to turn off to protect the first switch tube, and reports that there is a stall fault at the low-speed drive end of the wiper motor. When it is determined that there is a stall fault at the high-speed drive end of the wiper motor, a control instruction is sent to the gate driver, the gate driver controls the second switch tube to turn off to protect the second switch tube, and reports that there is a stall fault at the high-speed drive end of the wiper motor.

[0116] Sub-step seven, determining whether there is a short power fault in the wiper motor.

[0117] If the wiper motor has a short power fault, execute sub-step 8. If the wiper motor does not have a short power fault, execute sub-step 9.

[0118] Specifically, when the low gear is switched to the OFF gear, the gate driver will turn off the third switch tube when determining that the third switch tube has an overcurrent fault, so as to timely protect the third switch tube from being burned by a large current.

[0119] The controller determines whether the third switch tube has an overcurrent fault based on the switch tube fault data fed back by the gate driver, and further determines whether the wiper motor has a short power fault. Specifically, when the controller determines that the third switch tube has an overcurrent fault, it determines that the wiper motor has a short power fault; or, when the controller determines that the first drive current is less than or equal to the first current threshold and the third switch tube has an overcurrent fault, it determines that the low-speed drive end of the wiper motor has a short power fault; when the first drive current is a negative current and the third switch tube has an overcurrent fault, it determines that the high-speed drive end of the wiper motor has a short power fault.

[0120] Sub-step eight, reporting a short power fault in the wiper motor.

[0121] In one example, the controller directly reports that the wiper motor has a short power fault. In another example, the controller may report whether the short power fault exists at the low-speed drive end of the wiper motor or at the high-speed drive end.

[0122] Sub-step nine, determining whether the wiper motor has an open circuit fault.

[0123] If the wiper motor has an open circuit fault, execute sub-step 10. If the wiper motor does not have an open circuit fault, it is considered that the wiper motor is in a normal working state, and sub-step 1 can be executed again for judgment.

[0124] Specifically, when the wiper motor is in a low-speed operating state, if the controller determines that the first drive current is less than the first current threshold, it is determined that an open circuit fault exists at the low-speed drive end of the wiper motor; when the wiper motor is in a high-speed operating state, if the controller determines that the second drive current is less than the first current threshold, it is determined that an open circuit fault exists at the high-speed drive end of the wiper motor.

[0125] Sub-step ten: reporting an open circuit fault in the wiper motor.

[0126] Specifically, when there is an open circuit fault at the low speed driving end of the wiper motor, the open circuit fault at the low speed driving end of the wiper motor is reported. When there is an open circuit fault at the high speed driving end of the wiper motor, the open circuit fault at the high speed driving end of the wiper motor is reported.

[0127] In this implementation, the controller may report the failure of the wiper motor to the terminal device, and the terminal device may be a vehicle-mounted terminal, a mobile phone, a computer, etc., which is not specifically limited in this embodiment.

[0128] It should be noted that the relevant contents of the first current threshold, the second current threshold, the third current threshold and the fourth current threshold can be referred to Figure 3 The relevant descriptions in the illustrated embodiment are not repeated here. In addition, the fault diagnosis sequence of sub-steps 1 to 10 is only for illustration, and in other implementations, fault detection may also be performed in other fault diagnosis sequences, which are not specifically limited here.

[0129] In this embodiment, by obtaining the first drive current, the second drive current and the switch tube fault data, various faults of the wiper motor (including open circuit fault, overcurrent fault, stall fault, short ground fault and short power fault) are diagnosed, which greatly improves the safety and reliability of the wiper motor. In addition, after diagnosing the fault of the wiper motor, the corresponding fault is reported, which can help engineers quickly find the cause of the fault for easy maintenance.

[0130] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A wiper drive device, characterized in that: The wiper driving device comprises: Control unit; A first switch tube, wherein a controlled end of the first switch tube is connected to a first control signal output end of the control unit, and a first end of the first switch tube is used to be connected to a power supply; A backflow prevention unit, wherein a first end of the backflow prevention unit is connected to a second end of the first switch tube, and a second end of the backflow prevention unit is used to be connected to a low-speed driving end of a wiper motor; a second switch tube, wherein a controlled end of the second switch tube is connected to a second control signal output end of the control unit, a first end of the second switch tube is used to be connected to the power supply, and a second end of the second switch tube is used to be connected to a high-speed driving end of a wiper motor; The anti-backflow unit is used to prevent the current of the high-speed driving end from backflowing from the low-speed driving end to the first switch tube when the wiper motor is in a high-speed working state.

2. The wiper drive device according to claim 1, characterized in that: The anti-backflow unit includes a first diode, an anode of the first diode is connected to the drive signal output end of the first switch tube, and a cathode of the first diode is used to be connected to the low-speed drive end.

3. The wiper drive device according to claim 1, characterized in that: The wiper driving device further includes a third switch tube, a controlled end of the third switch tube is connected to a third control signal output end of the control unit, a first end of the third switch tube is connected to a second end of the backflow prevention unit, and a second end of the third switch tube is grounded; The control unit is used for controlling the third switch tube to be turned on in response to obtaining a wiper stop instruction and a wiper return signal.

4. The wiper drive device according to claim 3, characterized in that: The first detection end of the control unit is connected to the first end of the third switch tube, and the second detection end of the control unit is connected to the second end of the second switch tube; The control unit is used to obtain a first voltage corresponding to the first end of the third switch tube and a second voltage corresponding to the second end of the second switch tube; determine the fault state of the first switch tube based on the voltage of the power supply, the first voltage and the conduction voltage drop of the anti-backflow unit; determine the fault state of the second switch tube based on the voltage of the power supply and the second voltage; determine the fault state of the third switch tube based on the first voltage; wherein the fault state of each switch tube includes the presence of an overcurrent fault or the absence of the overcurrent fault; Furthermore, the control unit is further configured to shut down the target switch tube when determining that the target switch tube has the overcurrent fault, and the target switch tube is one of the first switch tube, the second switch tube and the third switch tube.

5. The wiper drive device according to claim 4, characterized in that: The control unit is further configured to perform short circuit fault detection on the wiper motor based at least on a fault state of the first switch tube, a fault state of the second switch tube, and a fault state of the third switch tube.

6. The wiper drive device according to claim 5, characterized in that: The control unit is used for determining that a short-to-ground fault exists in the wiper motor in response to the overcurrent fault existing in the first switch tube or the second switch tube; In response to the overcurrent fault of the third switch tube, determining that a short power fault exists in the wiper motor; Alternatively, in response to the first drive current being less than or equal to the first current threshold and the overcurrent fault existing in the third switch tube, it is determined that a short power fault exists in the low-speed drive end; In response to the first drive current being a negative current and the third switch tube having the overcurrent fault, it is determined that the high-speed drive end has the short power fault; wherein the first drive current is the drive current flowing through the low-speed drive end.

7. The wiper drive device according to claim 1, characterized in that: The wiper drive device also includes a first resistor, a second resistor, a first detection circuit and a second detection circuit; wherein the first end of the first resistor is connected to the second end of the anti-backflow unit, the second end of the first resistor is used to connect to the low-speed drive end, and the first detection circuit is used to detect the voltage across the first resistor; the first end of the second resistor is connected to the second end of the second switch tube, the second end of the second resistor is used to connect to the high-speed drive end, and the second detection circuit is used to detect the voltage across the second resistor; The control unit is used to determine a first driving current flowing through the low-speed driving end based on a voltage across the first resistor, and to determine a second driving current flowing through the high-speed driving end based on a voltage across the second resistor; The control unit is further used to, when controlling the wiper motor to be in a target working state, determine that an open circuit fault exists at a target drive end of the wiper motor in response to a target drive current being less than a first current threshold; determine that an overcurrent fault exists at the target drive end in response to the target drive current being greater than or equal to a second current threshold and less than a third current threshold; and determine that a stall fault exists at the target drive end in response to the target drive current being greater than or equal to the third current threshold and less than a fourth current threshold; Among them, when the target working state is a low-speed working state, the target driving current is the first driving current, and the target driving end is the low-speed driving end; when the target working state is a high-speed working state, the target driving current is the second driving current, and the target driving end is the high-speed driving end.

8. The wiper drive device according to claim 1, characterized in that: The wiper drive device further includes a first freewheeling unit and a second freewheeling unit; the first end of the first freewheeling unit is connected to the second end of the backflow prevention unit, and the second end of the first freewheeling unit is grounded; the first end of the second freewheeling unit is connected to the second end of the second switch tube, and the second end of the second freewheeling unit is grounded; The control unit is used for controlling the first switch tube to turn off in response to an overcurrent fault or a stall fault at the low-speed driving end; In response to an overcurrent fault or a stall fault at the high-speed driving end, controlling the second switch tube to turn off; The first freewheeling unit is used to form a first freewheeling loop with the wiper motor and the ground terminal at the moment the first switch tube is turned off, and the second freewheeling unit is used to form a second freewheeling loop with the wiper motor and the ground terminal at the moment the second switch tube is turned off.

9. The wiper drive device according to claim 8, characterized in that: The first freewheeling unit includes a second diode, a cathode of the second diode is connected to the second end of the backflow prevention unit, and an anode of the second diode is grounded.

10. The wiper drive device according to claim 9, characterized in that: The first freewheeling unit further includes a third switch tube, the second diode is a body diode of the third switch tube; the controlled end of the third switch tube is connected to the third control signal output end of the control unit, the first end of the third switch tube is connected to the second end of the backflow prevention unit, and the second end of the third switch tube is grounded; The control unit is further configured to control the third switch tube to be turned on after executing the step of controlling the first switch tube to be turned off.

11. The wiper driving device according to claim 8, characterized in that: The second freewheeling unit includes a third diode, a cathode of the third diode is connected to the second end of the second switch tube, and an anode of the third diode is grounded.

12. A wiper control system, characterized in that: It comprises a wiper motor and a wiper driving device as claimed in any one of claims 1 to 11.

13. A vehicle, characterized in that: Includes the wiper control system as claimed in claim 12.

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