WO2020224645A1

WO2020224645A1 - Speed regulation control system for windshield wiper

Info

Publication number: WO2020224645A1
Application number: PCT/CN2020/089214
Authority: WO
Inventors: 张国旭; 华东旭; 房军; 姜亦强
Original assignee: 上海禹点电子科技有限公司
Priority date: 2019-05-08
Filing date: 2020-05-08
Publication date: 2020-11-12

Abstract

A speed regulation control system for a windshield wiper, comprising an electric motor (3), a connecting rod structure, a control module (1) and a sensing module (2), wherein the connecting rod structure converts a unidirectional movement of the electric motor (3) into a reciprocating movement of a windshield wiper on a glass panel; the sensing module (2) is used for sensing a discrete signal or a continuous signal according to one cycle of the unidirectional movement of the electric motor (3); the control module (1) is respectively in electrical signal connection with the electric motor (3) and the sensing module (2); and the control module (1) provides, according to a signal fed back by the sensing module (2), a target driving effective voltage corresponding to the signal and for controlling the electric motor (3) to the electric motor (3), such that the electric motor (3) is driven by means of the target driving effective voltage corresponding to each group of signals during the unidirectional movement of the electric motor (3), thereby regulating the movement speed of the windscreen wiper.

Description

A speed control system of wiper

Technical field

The utility model relates to the technical field of wiper speed regulation, in particular to a wiper speed regulation control system.

Background technique

Wiper blades, also known as wipers, wipers, wipers or windshield wipers, are devices used to wipe off raindrops and dust attached to the windshield of a vehicle to improve the visibility of the driver and increase driving safety.

The high-speed and low-speed wipers are respectively controlled to perform high-speed and low-speed wiping. The wiper is driven by a motor through a connecting rod structure. There are two general driving methods:

One driving method is that the motor rotates in one direction at a uniform speed, and then through the connecting rod structure, the one-week one-way motion is converted into the reciprocating motion of the wiper on the glass surface; this driving method is generally difficult at the wiper reverse point. Adjust the reverse speed of the wiper well, and bring the following problems:

1) When designing, it is necessary to reserve a larger distance from the A-pillar. Because the wiper blade has a certain flexibility, the wiper blade is closer to the A-pillar when the wiper wipes at a high speed. Therefore, a larger distance is required. The distance of the A-pillar, in this case, affects the wiper area and the driver’s subjective feelings;

2) The wiper blade generates a lot of noise at the position of the reversal point. For example, the wiper blade reversing too fast will cause greater reversing noise.

Another driving method is to control the forward and reverse switching of the motor, and convert the forward and reverse rotation of the motor into the reciprocating movement of the wiper on the glass surface through the connecting rod structure. By adjusting the running speed of the motor forward and reverse in real time, and the running speed of the wiper on the glass surface, the movement speed and reverse noise of the wiper at the reversal point area can be controlled. However, due to the need to control the forward and reverse rotation of the motor, this driving method requires a higher-cost motor, and the overall system cost will be higher.

Summary of the invention

The present application provides a wiper dispatching control system, which can solve the problem that it is difficult to adjust the reverse speed of the wiper when the motor drives the wiper in one-way motion.

In order to solve the above problems, the technical solution of this application is as follows:

This application provides a wiper speed control system, which includes a motor and a connecting rod structure. One end of the connecting rod structure is connected to the output end of the motor, and the other end is connected to the wiper. The movement is transformed into the reciprocating movement of the wiper on the glass surface, which also includes a control module and a sensor module;

The induction module is installed in cooperation with the motor, and the induction module is used for inducing a discrete signal or a continuous signal according to a one-way movement of the motor;

The control module is respectively connected with electrical signals of the motor and the induction module, and the control module provides the motor with a target driving effective voltage corresponding to the signal to the motor according to the signal fed back by the induction module , So that in the unidirectional movement of the motor, the effective voltage is driven by the target corresponding to each signal to drive the motor, thereby adjusting the moving speed of the wiper.

In an embodiment, the induction module includes a magnetic position sensor and a magnetic device;

The magnetic device is installed on the output shaft of the motor, and the magnetic device rotates synchronously with the output shaft of the motor;

The magnetic position sensor is located above the magnetic device, and when the magnetic device rotates once with the motor, the magnetic position sensor induces a discrete signal or a continuous signal through the magnetic field intensity of the magnetic device.

In an embodiment, the magnetic position sensor is a single Hall sensor, and the magnetic device is a magnetic sheet or a magnetic ring;

The magnetic sheet or magnetic ring is mounted on the worm gear of the motor, and the magnetic sheet or magnetic ring rotates synchronously with the output shaft of the motor;

The single Hall sensor is located above the edge contour of the projective area of the magnetic sheet or the magnetic ring, and when the magnetic sheet or the magnetic ring rotates once with the motor, the single Hall sensor passes through the magnetic sheet or The magnetic field strength of the magnetic ring induces two sets of signals.

In an embodiment, the magnetic position sensor is a double Hall sensor, and the magnetic device is a magnetic sheet or a magnetic ring;

The dual Hall sensor is located above the edge contour of the projective area of the magnetic sheet or magnetic ring, and when the magnetic sheet or magnetic ring rotates once with the motor, the dual Hall sensor passes through the magnetic sheet or The magnetic field strength of the magnetic ring induces four sets of signals.

In an embodiment, the magnetic position sensor is a combination of a double Hall sensor and a single Hall sensor, and the magnetic device is a magnetic sheet or a magnetic ring;

The magnetic sheet or the magnetic ring is mounted on the worm gear of the motor, and the magnetic sheet or the magnetic ring rotates with the output shaft of the motor;

The magnetic position sensor is located above the edge contour of the projective area of the magnetic sheet or the magnetic ring, and when the magnetic sheet or the magnetic ring rotates once with the motor, the magnetic position sensor passes through the magnetic sheet or the magnetic ring. The intensity of the magnetic field induces eight sets of signals.

In an embodiment, the magnetic position sensor is a linear Hall sensor, and the magnetic device is a magnetic sheet or a magnetic ring;

The linear Hall sensor is located directly above the projective area of the magnetic sheet or magnetic ring, and the center of the sensing area of the linear Hall sensor is coaxial with the center of the projective area. The magnetic sheet or magnetic ring When the motor rotates once, the linear Hall sensor induces a continuous signal through the magnetic field strength of the magnetic sheet or magnetic ring.

In an embodiment, the distance between adjacent Hall sensors is a preset distance.

In an embodiment, the control module includes: a main control unit and a power drive circuit;

The output terminal of the main control unit is electrically connected with the power drive circuit, the power drive circuit is used to drive the motor to rotate in one direction, and the main control unit is signally connected with the induction module;

When the power drive circuit controls the one-way rotation of the motor, the control module provides the power drive circuit with a target drive effective voltage corresponding to the signal to control the motor according to the signal fed back by the induction module , So that in the one-way movement of the motor, the effective voltage is driven by the target corresponding to each group of signals to drive the motor, thereby adjusting the moving speed of the wiper.

In an embodiment, the power drive circuit includes any one of the following combinations:

The combination of PMOS and NMOS, in which the motor high-side drive is used, and the reserved sampling resistor is set at the lower end of the motor. When the motor is working normally, the low-side MOS and the high-side MOS are turned on in opposite phases, and the high-side MOS is turned off when the motor stops. And turn on the low-side MOS to provide braking force for the motor;

Combination of PMOS and NMOS, in which the motor low-side drive is adopted, and the reserved sampling resistor is set at the lower end of the low-side MOS. When the motor is working normally, the high-side MOS and the low-side MOS are turned on in opposite phases, and the low-side is turned off when the motor stops. MOS, and turn on high-side MOS to provide braking force for the motor;

The combination of NMOS and NMOS, in which the high-side motor is driven, and the reserved sampling resistor is set at the lower end of the motor. When the motor is working normally, the low-side MOS and the high-side MOS are turned on in opposite phases, and the high-side MOS is turned off when the motor stops. And turn on the low-side MOS to provide braking force for the motor;

NMOS and NMOS combination, in which the motor low-side drive is adopted, and the reserved sampling resistor is set at the lower end of the low-side MOS. When the motor works normally, the high-side MOS and the low-side MOS are turned on in opposite phases, and the low-side is turned off when the motor stops. MOS, and turn on the high-side MOS to provide braking force for the motor.

In an embodiment, the main control unit includes a main control MCU and a driving circuit;

The main control MCU is coupled to the input end of the drive circuit, the output end of the drive circuit is coupled to the input end of the power drive circuit, and the main control MCU is also signally connected to the sensing module. The master control MCU provides the driving circuit with a duty ratio of the target driving effective voltage corresponding to the signal, and the driving circuit drives the power driving circuit based on the duty ratio.

In an embodiment, the main control unit further includes an amplifier, the input end of the amplifier is coupled to the power drive circuit, and the output end of the amplifier is coupled to the main control MCU, so that the main control MCU , The driving circuit, the power driving circuit and the amplifier form a closed-loop control, and the main control MCU controls the duty ratio output to the driving circuit according to the sampled electrical signal of the power driving circuit fed back by the amplifier.

In an embodiment, the main control unit further includes a power supply module, and the power supply module is used to supply power to the main control MCU and supply power to the induction module.

In an embodiment, at least one of the components of the main control unit is a discrete structure.

In an embodiment, the main control unit is an integrated integrated circuit chip, and each component of the main control unit is integrated on the integrated circuit chip.

In one embodiment, the control module further includes an anti-reverse connection circuit, and the output end of the anti-reverse connection circuit is coupled to the power supply module to prevent the main control unit from being connected reversely.

In an embodiment, the control module further includes a filter circuit, one end of the filter circuit is coupled to the power supply module, and the other end is coupled to the power drive circuit, and the filter circuit is used to supply power to the power drive circuit It is also used to suppress the external emission of the PWM drive waveform of the power drive circuit.

In an embodiment, the control module further includes a temperature sensor, and the temperature sensor is coupled with the main control MCU.

According to the speed control system of the above-mentioned embodiment, the effective voltage of the motor is controlled during the reciprocating movement of the wiper in one direction by the motor, and the variable speed movement of the wiper is controlled, for example, the wiper can be reduced in speed near the reverse point. In the middle area of the reversal point, the wiper is controlled to accelerate in a certain way to increase the wiping speed, so as to ensure that the wiper is adjustable in the entire wiping cycle, reducing the elastic deformation of the wiper blade during high-speed wiping, and at the same time reducing The small wiper reverses the noise.

Description of the drawings

Figure 1 is a block diagram of the principle of the speed control system;

Figure 2 is a schematic diagram of the circuit corresponding to Figure 1;

Fig. 3 is a schematic diagram of a specific application example of Fig. 1;

Figure 4 is a schematic diagram of the angular interval division based on a single Hall signal;

Figure 5 is a schematic diagram of an angular velocity curve based on a single Hall signal;

Fig. 6 is a schematic diagram of the division of angle intervals based on dual Hall signals;

Figure 7 is a schematic diagram of an angular velocity curve based on dual Hall signals;

Figure 8 is a schematic diagram of the coordinated structure of the speed control system and the motor.

Detailed ways

Hereinafter, the present utility model will be further described in detail through specific embodiments in conjunction with the drawings.

This example first provides an exemplary existing application scenario. The wiper used on a car is driven by a motor combined with a connecting rod structure. One of the driving methods is that the unidirectional movement of the motor is converted into a wiper through the connecting rod structure. The reciprocating movement on the glass surface, but the external power supply voltage of the motor is fixed (that is, the actual voltage provided to the motor is fixed), which results in a fixed speed of the motor. The motor can only run at a uniform speed in one direction, and the wiper cannot be scheduled.

Based on the above application scenarios, in the embodiment of the present utility model, a speed control system for wipers is provided. The design idea of the method is to convert the unidirectional movement of the motor into the reciprocating movement of the wiper, and In one-way motion, the target drive effective voltage of the motor is controlled, so that the motor adjusts the moving speed of the wiper based on the target drive effective voltage.

Through the above design ideas, when the motor drives the wiper back and forth in one direction, the effective voltage of the motor is controlled to control the variable speed movement of the wiper. For example, the wiper can slow down near the reversal point, and at the reverse point The middle area controls the wiper to accelerate in a certain way to increase the wiping speed, so as to ensure that the operating speed of the wiper is adjustable during the entire wiping cycle, reducing the elastic deformation of the wiper blade during high-speed wiping, and reducing the reverse of the wiper. Turn the noise.

In order to realize the above design ideas, the speed control system of this example includes a motor, a connecting rod structure, a control module, and an induction module. The schematic diagrams of the system are shown in Figure 1, Figure 2 and Figure 3.

Among them, the connection relationship between the motor, the connecting rod structure and the wiper blade, and the principle that the connecting rod structure converts the one-way motion of the motor into the reciprocating motion of the wiper blade on the glass surface is the prior art, and will not be repeated in this example. , The improvement made in this example is that under the premise of the original motor and connecting rod structure unchanged, by adding control modules and induction modules, the induction module and the motor are installed in cooperation. The induction module is used according to the unidirectional motor Discrete signals or continuous signals are induced in one movement; the control module is respectively connected with the electrical signals of the motor and the induction module, and the control module provides the motor with the target driving effective voltage corresponding to the signal corresponding to the signal from the feedback module of the induction module. So that in the one-way movement of the motor, the effective voltage is driven by the target corresponding to each group of signals to drive the motor, thereby adjusting the moving speed of the wiper.

The basic realization principle is: in order to control the variable speed movement of the motor during the unidirectional movement of the motor, an induction module is added in this application, and the signal of the one-way movement of the motor is induced through the induction module, and then the control module feedbacks according to the induction module The current signal of provides the motor with a target driving effective voltage corresponding to the current signal to control the motor.

Specifically, in practical applications, according to the specific structural design of the induction module, when the motor moves in one direction (0-360°), the induction module can sense discrete signals or continuous signals. In this example, the induction module includes Magnetic position sensor and magnetic device. The magnetic device is installed on the output shaft of the motor, and the magnetic device rotates synchronously with the output shaft of the motor; the magnetic position sensor is located above the magnetic device. When the magnetic device rotates with the motor once, the magnetic position sensor passes through the magnetic device. The intensity of the magnetic field induces discrete or continuous signals. In practical applications, discrete or continuous signals can be sent to the control module through digital, analog, or SPI signals; therefore, it is understandable that without special instructions The signal induced by the magnetic position sensor in this example refers to the position signal of the motor rotation, where the magnetic position sensor can be a magnetic position/angle sensor such as AMR, TMR, GMR, etc. In the following, a detailed description of the sensor module will be given by taking the discrete signal that the sensor module can sense as an example.

In one embodiment, the magnetic position sensor is a single Hall sensor, and the magnetic device is a magnetic sheet or a magnetic ring, wherein the magnetic sheet or magnetic ring is mounted on the worm wheel of the motor, and the magnetic sheet or magnetic ring rotates synchronously with the motor output shaft; The Hall sensor is located above the edge contour of the projective area of the magnetic sheet or magnetic ring, and when the magnetic sheet or magnetic ring rotates one circle with the motor, the single Hall sensor induces two sets of signals through the magnetic field strength of the magnetic sheet or magnetic ring.

Specifically, install the magnetic sheet or magnetic ring with N pole and S pole to the center of the worm gear of the motor, the magnetic sheet or magnetic ring rotates synchronously with the output shaft of the motor, and the deviation of the single Hall sensor and the magnetic sheet or magnetic ring is set. When the sheet or magnetic ring rotates with the motor, the single Hall sensor generates one induction signal through the magnetic field strength of the magnetic sheet or magnetic ring. Therefore, when the motor rotates one round in one direction, the single Hall sensor induces two sets of signals.

In order to provide different target driving effective voltages to the motor for two different position signals, this example divides the angle interval (0, 2π) of the motor one revolution into two angle intervals according to the two sets of signals induced by a single Hall sensor. It is the first angle interval and the second angle interval.

As shown in FIG. 4, the angle interval for one rotation of the motor includes an angle interval AB and an angle interval BA, wherein the range of the angle interval AB is (0, π), and the range of the angle interval BA is (π, 2π).

In this case, the control module is preset with the target driving effective voltage corresponding to the two sets of signals. When the control module obtains the signal feedback from the single Hall sensor, the control module provides the motor with the target corresponding to the signal The effective voltage is driven so that in the unidirectional movement of the motor, the effective voltage is driven by the target corresponding to each set of signals to drive the motor, and then the movement speed of the wiper is adjusted. Among them, the angular velocity of the motor in each rotation angle interval is shown in Figure 5. Show.

In another embodiment, the magnetic position sensor is a double Hall sensor, and the magnetic device is a magnetic sheet or magnetic ring; wherein the magnetic sheet or magnetic ring is installed on the worm wheel of the motor, and the magnetic sheet or magnetic ring rotates synchronously with the motor output shaft; The dual Hall sensor is located above the edge contour of the projective area of the magnetic sheet or magnetic ring, and when the magnetic sheet or magnetic ring rotates one circle with the motor, the dual Hall sensor induces four sets of signals.

Specifically, the magnetic sheet or magnetic ring with N pole and S pole is installed in the center of the worm wheel of the motor, the magnetic sheet or magnetic ring rotates synchronously with the motor output shaft, and the deviation of the dual Hall sensor and the magnetic sheet or magnetic ring is set. Or when the magnetic ring rotates with the motor, the dual Hall sensor generates two induction signals through the magnetic field strength of the magnetic sheet or the magnetic ring, each of which generates two groups of induction signals. Therefore, when the motor rotates one cycle in one direction, the double Hall sensor The Seoul sensor senses four sets of signals.

In order to provide the motor with different target driving effective voltages for four different position signals, this example divides the angle interval (0, 2π) of the motor's one revolution into four angle intervals according to the four sets of signals induced by the double Hall sensor. It is the first angle interval, the second angle interval, the third angle interval and the fourth angle interval.

As shown in FIG. 6, the range of the first angle interval AB is (0, 2/3π), the range of the second angle interval BC is (2/3π, π), and the range of the third angle interval CD is (π , 5/3π), and the range of the fourth angle interval DA is (5/3π, 2π).

In this case, the control module is preset with the target driving effective voltage corresponding to each of the four sets of signals. When the control module obtains the signal fed back by the double Hall sensor, the control module provides the motor with the target corresponding to the signal The effective voltage is driven so that in the one-way movement of the motor, the effective voltage is driven by the target corresponding to each set of signals to drive the motor, and then the movement speed of the wiper is adjusted. Among them, the angular velocity of the motor in each rotation angle interval is shown in Figure 7. Show.

In another embodiment, the magnetic position sensor is a combination of a double Hall sensor and a single Hall sensor, and the magnetic device is a magnetic sheet or magnetic ring; the magnetic sheet or magnetic ring is installed on the worm wheel of the motor, the magnetic sheet or magnetic ring and the motor The output shaft rotates in the same direction; the magnetic position sensor is located above the edge contour of the projective area of the magnetic sheet or magnetic ring, and when the magnetic sheet or magnetic ring rotates with the motor for one cycle, the magnetic position sensor induces eight through the magnetic field intensity of the magnetic sheet or magnetic ring. Group signals.

Similarly, in order to provide different target driving effective voltages to the motor for eight different position signals, this example divides the angle interval (0, 2π) of the motor rotation into eight angles according to the eight sets of signals sensed by the dual Hall sensors. Interval; and, the control module is preset with the target drive effective voltage corresponding to each of the eight groups of signals. When the control module obtains the signal fed back by the dual Hall sensor, the control module provides the motor with the target drive corresponding to the signal Effective voltage, so that in the one-way movement of the motor, the effective voltage is driven by the target corresponding to each group of signals to drive the motor, thereby adjusting the moving speed of the wiper.

It should be noted that when the magnetic position sensor is a dual Hall sensor, or a dual Hall sensor and a single Hall sensor form a triple Hall sensor, two Hall sensors or three Hall sensors are required to be arranged on the magnetic sheet. Or above the edge contour of the projective area of the magnetic ring, but the distance between adjacent Hall sensors needs to be arranged according to the preset distance. Taking two Hall sensors A and B as an example, the calculation formula for the preset distance is :

ψ _tgt =ψ _set -(α-β);

Among them, B ₀ is the field strength when the Hall sensor level is flipped, B _A is the peak field strength of the measurement point A, _BB is the peak field strength of the measurement point B, ψ _set is the target angle; L _A is the Hall sensor The field strength distance from sensor A to the magnetic sheet or magnetic ring, L _B is the field strength distance from Hall sensor B to the magnetic sheet or magnetic ring, and d is the preset distance between Hall sensor A and Hall sensor B.

In the following, the sensor module will be described in detail by taking the continuous signal that the sensor module can sense as an example.

In one embodiment, the magnetic position sensor is a linear Hall sensor, and the magnetic device is a magnetic sheet or magnetic ring; the magnetic sheet or magnetic ring is mounted on the worm wheel of the motor, and the magnetic sheet or magnetic ring rotates with the motor output shaft; The sensor is located directly above the projective area of the magnetic sheet or magnetic ring, and the center of the sensing area of the linear Hall sensor is coaxial with the center of the projective area. When the magnetic sheet or magnetic ring rotates with the motor once, the linear Hall sensor passes through the magnetic The magnetic field strength of the sheet or magnetic ring induces a continuous signal.

Specifically, the magnetic sheet or magnetic ring with N pole and S pole is installed in the center of the worm gear of the motor, the magnetic sheet or magnetic ring rotates synchronously with the motor output shaft, and the induction area of the linear Hall sensor is projected with the magnetic sheet or magnetic ring The center of the interval is set coaxially. When the magnetic sheet or magnetic ring rotates with the motor, the linear Hall sensor generates a continuous induction signal through the magnetic field strength of the magnetic sheet or magnetic ring. Therefore, when the motor rotates one round in one direction, the linear Hall sensor The Er sensor senses a continuous signal.

In this case, the control module is preset with the target drive effective voltage corresponding to the continuous signal. When the control module obtains the signal fed back by the linear Hall sensor, the control module provides the motor with the target drive corresponding to the signal Effective voltage, so that in the one-way movement of the motor, the effective voltage is driven by the target corresponding to each signal to drive the motor, thereby adjusting the moving speed of the wiper.

Regardless of whether the induction module induces a discrete signal or a continuous signal, the signal essentially reflects the position signal of the motor rotation. For example, if the induction module induces two sets of signals, the angular interval of the motor's movement can be divided into two rotations Angle interval, and each group of signals is used to reflect the position signal of each rotation angle interval; Similarly, if the sensor module induces four groups of signals, the angle interval of the motor's movement can be divided into four rotation angle intervals, and each group The signal is used to reflect the position signal of each rotation angle interval. The control module provides the target driving effective voltage corresponding to the control motor to the motor according to the signal feedback from the induction module, that is, the control module can provide the corresponding target driving effective voltage within the rotation angle interval to which the motor belongs, so that When the motor moves in a single direction for one cycle, there are different target driving effective voltages corresponding to different rotation angle intervals. Furthermore, the motor controls the movement speed of the wiper according to different target driving effective voltages in different rotation angle intervals, so as to adjust the wiper speed For example, the wiper can be slowed down near the reversal point, and the wiper is controlled to accelerate in a certain way in the middle area of the reversal point to increase the wiper speed, so as to ensure that the wiper operates in the entire wiper cycle. Adjustable to reduce the elastic deformation of the wiper blade during high-speed wiping, and at the same time reduce the reverse noise of the wiper.

In addition, the magnetic position sensor and the control module in the above embodiments are mounted on the PCB board together, and the induction module described in the above embodiments does not exhaustively list the design structure of the induction module. A person skilled in the art performs deformation processing on the induction module on the basis of each embodiment, so that the induction module induces a discrete signal or a continuous signal for one rotation of the motor, which should fall within the protection scope of this application.

The composition structure of the control module is described below.

The control module includes a main control unit and a power drive circuit. The output end of the main control unit is electrically connected to the power drive circuit. The power drive circuit is used to drive the motor to rotate in one direction, and the main control unit is signally connected to the induction module; power drive In the process that the circuit controls the motor to rotate in one direction, the control module provides the power drive circuit with the target drive effective voltage corresponding to the signal to the power drive circuit according to the signal fed back by the induction module, so that in the one-way movement of the motor, the The target corresponding to the group signal drives the effective voltage to drive the motor, and then adjusts the moving speed of the wiper.

Among them, the power drive circuit consists of the following four combinations:

1) Combination of PMOS and NMOS, the motor is driven by the high-side, and the sampling resistor is reserved at the lower end of the motor. When the motor is working normally, the low-side MOS and the high-side MOS are turned on in opposite phases, and the high-side MOS is turned off and turned on immediately when the motor stops. Low-side MOS provides braking force for the motor; in this combination, whether low-side MOS and high-side MOS specifically use PMOS or NMOS is not specifically limited, as long as it is a combination of PMOS and NMOS.

2) Combination of PMOS and NMOS, the motor is driven at the low side, and the sampling resistor is reserved at the lower end of the low side MOS. When the motor is working normally, the high side MOS and the low side MOS are turned on in opposite phases, and the low side MOS is turned off immediately when the motor stops. And turn on the high-side MOS to provide braking force for the motor; in this combination, whether the low-side MOS and the high-side MOS are specifically PMOS or NMOS is not specifically limited, as long as it is a combination of PMOS and NMOS.

3) Combination of NMOS and NMOS, the motor is driven by the high-side, and the sampling resistor is reserved at the lower end of the motor. When the motor is working normally, the low-side MOS and the high-side MOS are turned on in opposite phases, and the high-side MOS is turned off and turned on immediately when the motor stops. Low-side MOS provides braking force for the motor.

4) Combination of NMOS and NMOS, the motor is driven at the low side, and the sampling resistor is reserved at the lower end of the low side MOS. When the motor is working normally, the high side MOS and the low side MOS are turned on in opposite phases, and the low side MOS is turned off immediately when the motor stops. And turn on the high-side MOS to provide braking force for the motor.

In the above-mentioned combination mode, one MOS is used as the main drive, and the other MOS is connected in parallel with the motor, which has a freewheeling function and provides braking when the motor stops.

In addition to the above-mentioned combination, in other embodiments, the power drive circuit may also adopt a combination of a relay and a diode.

In an embodiment, the main control unit includes a main control MCU and a drive circuit, wherein the main control MCU is coupled with the input end of the drive circuit, the output end of the drive circuit is coupled with the input end of the power drive circuit, and the main control MCU is also coupled with the sensor Module signal connection, the main control MCU provides the drive circuit with the duty cycle of the target driving effective voltage corresponding to the signal, and the drive circuit drives the power drive circuit based on the duty cycle; specifically, the main control MCU according to the current signal fed back by the sensing module , Find out the pre-stored target driving effective voltage that matches the current signal, and then calculate the duty cycle according to the target driving effective voltage and the actual supply voltage, and finally send the duty cycle to the driving circuit, and the driving circuit The ratio amplifies and converts the voltage of the success rate drive circuit so that the power drive circuit drives the motor to rotate in one direction according to the duty ratio.

The above-mentioned main control MCU, drive circuit and power drive circuit are under open-loop control. In another embodiment, the main control unit further includes an amplifier, the input end of which is coupled to the power drive circuit, and the output end of the amplifier is coupled To the main control MCU, the main control MCU, the drive circuit, the power drive circuit and the amplifier form a closed-loop control. The main control MCU controls the duty cycle output to the drive circuit according to the sampled electrical signal of the power drive circuit fed back by the amplifier; specifically, The input of the amplifier is coupled to the sampling resistor in the power drive circuit to feed the voltage signal or current signal of the sampling resistor to the main control MCU. The main control MCU self-adjusts the output to the drive circuit according to the voltage signal or current signal fed back by the amplifier. Duty cycle to achieve precise control of motor speed.

Further, the main control unit further includes a power supply module, which is used to supply power to the main control MCU. It should be noted that at least one of the components of the main control unit is a discrete structure, for example, the main control MCU, drive circuit, amplifier and power module are independent modules; or, the main control unit is an integrated one On the PCB board, the components of the main control unit are integrated on the integrated PCB board, for example, the main control MCU, the driving circuit, the amplifier and the power module are integrated and arranged on the integrated PCB board.

Furthermore, the control module of this example also includes an anti-reverse connection circuit, wherein the output end of the anti-reverse circuit is coupled to the power supply module to prevent the main control unit from being reversed; for this reason, the control module also includes a charge pump, and a charge pump The input end of the charge pump is coupled to the main control MCU, and the output end of the charge pump is coupled to the anti-reverse connection circuit. The charge pump provides voltage to the anti-reverse connection circuit according to the control command of the main control MCU to make the anti-reverse connection circuit work.

The anti-reverse connection circuit in this example has the following four structures:

1) Independent anti-reverse diode;

2) The positive pole of the power supply P-type MOSFET is used for anti-reverse, the S pole of the PMOS is connected to the external power supply, and the G pole is grounded through a resistor. The two ends of the GS adopt a resistor divider, and a clamping diode ZD and capacitor are added to prevent excessive voltage from breakdown MOS;

3) Adopt power negative N-type MOSFET to prevent reverse, NMOS D pole is connected to the external ground, G pole is connected to the power supply through a resistor, GS two ends are divided by resistors, and a clamping diode ZD and capacitor are added to prevent excessive voltage from breakdown MOS ；

4) The positive N-type MOSFET of the power supply is used for anti-reverse, the S pole of the NMOS is connected to the external power supply, and the G pole is connected to the charge pump output of the MCU through a resistor. The two ends of the GS use resistor divider, and the clamping diode ZD and capacitor are added to prevent overvoltage Large breakdown of MOS.

The reverse withstand voltage of MOS or diode in the above anti-reverse circuit needs to be above 40V.

Further, the control module further includes a filter circuit, one end of the filter circuit is coupled to the power supply module, and the other end is coupled to the power drive circuit. The filter circuit is used to supply power to the power drive circuit and is also used to suppress the external emission of PWM drive waveforms of the power drive circuit; Yes, the filter circuit is an LC filter circuit. The LC filter circuit suppresses the external emission of the PWM drive waveform inside the power drive circuit. The capacitor needs an aluminum electrolytic capacitor above 680UF. There can be no aluminum electrolysis on the left side of the Π type, but it needs more than 1uF and several 100nF, 1nF, MLCC such as 10pF.

Further, the control module of this example also includes a temperature sensor, which is used to sense the temperature of the PCB board and the temperature of the worm wheel of the motor. The temperature sensor is coupled with the main control MCU to feed back the sensed temperature to the main control MCU in real time; The sensor can be a positive temperature coefficient thermistor (PTC) or a negative temperature coefficient thermistor (NTC).

The structure diagram of the control module, the induction module and the motor in this example is shown in Figure 8. After the control module 1 and the induction module 2 are installed in the motor 3, the control module 1 sends the feedback signal to the induction module 2 The motor 3 provides the target drive effective voltage corresponding to the signal to control the motor 3, so that in the unidirectional movement of the motor 3, the motor 3 is driven by the target drive effective voltage corresponding to each group of signals. The variable speed movement is converted into the reciprocating variable speed movement of the wiper on the glass surface, thereby adjusting the movement speed of the wiper.

The above application of specific examples to illustrate the utility model is only used to help understand the utility model, not to limit the utility model. For those skilled in the technical field to which the present utility model belongs, based on the idea of the present utility model, several simple deductions, deformations or substitutions can also be made.

Claims

A windshield wiper speed control system includes a motor and a connecting rod structure. One end of the connecting rod structure is connected with the output end of the motor, and the other end is connected with the wiper blade. The connecting rod structure converts the unidirectional movement of the motor into The reciprocating movement of the wiper on the glass surface is characterized in that it also includes a control module and an induction module;

The induction module is installed in cooperation with the motor, and the induction module is used for inducing a discrete signal or a continuous signal according to a one-way movement of the motor;

The control module is respectively connected with electrical signals of the motor and the induction module, and the control module provides the motor with a target driving effective voltage corresponding to the signal to the motor according to the signal fed back by the induction module , So that in the unidirectional movement of the motor, the effective voltage is driven by the target corresponding to each signal to drive the motor, thereby adjusting the moving speed of the wiper.
The speed control system according to claim 1, wherein the induction module includes a magnetic position sensor and a magnetic device, wherein the type of the magnetic position sensor is AMR, TMR, GMR or continuous Hall;

The magnetic device is installed on the output shaft of the motor, and the magnetic device rotates synchronously with the output shaft of the motor;

The magnetic position sensor is located above the magnetic device, and when the magnetic device rotates once with the motor, the magnetic position sensor induces a discrete signal or a continuous signal through the magnetic field intensity of the magnetic device.
The speed control system according to claim 2, wherein the magnetic position sensor is a single Hall sensor, and the magnetic device is a magnetic sheet or a magnetic ring;

The magnetic sheet or magnetic ring is mounted on the worm gear of the motor, and the magnetic sheet or magnetic ring rotates synchronously with the output shaft of the motor;

The single Hall sensor is located above the edge contour of the projective area of the magnetic sheet or the magnetic ring, and when the magnetic sheet or the magnetic ring rotates once with the motor, the single Hall sensor passes through the magnetic sheet or The magnetic field strength of the magnetic ring induces two sets of signals.
The speed control system according to claim 2, wherein the magnetic position sensor is a double Hall sensor, and the magnetic device is a magnetic sheet or a magnetic ring;

The magnetic sheet or magnetic ring is mounted on the worm gear of the motor, and the magnetic sheet or magnetic ring rotates synchronously with the output shaft of the motor;

The dual Hall sensor is located above the edge contour of the projective area of the magnetic sheet or magnetic ring, and when the magnetic sheet or magnetic ring rotates once with the motor, the dual Hall sensor passes through the magnetic sheet or The magnetic field strength of the magnetic ring induces four sets of signals.
The speed control system according to claim 2, wherein the magnetic position sensor is a combination of a double Hall sensor and a single Hall sensor, and the magnetic device is a magnetic sheet or a magnetic ring;

The magnetic sheet or the magnetic ring is mounted on the worm gear of the motor, and the magnetic sheet or the magnetic ring rotates with the output shaft of the motor;

The magnetic position sensor is located above the edge contour of the projective area of the magnetic sheet or the magnetic ring, and when the magnetic sheet or the magnetic ring rotates once with the motor, the magnetic position sensor passes through the magnetic sheet or the magnetic ring. The intensity of the magnetic field induces eight sets of signals.
The speed control system according to claim 2, wherein the magnetic position sensor is a linear Hall sensor, and the magnetic device is a magnetic sheet or a magnetic ring;

The magnetic sheet or the magnetic ring is mounted on the worm gear of the motor, and the magnetic sheet or the magnetic ring rotates with the output shaft of the motor;

The linear Hall sensor is located directly above the projective area of the magnetic sheet or magnetic ring, and the center of the sensing area of the linear Hall sensor is coaxial with the center of the projective area. The magnetic sheet or magnetic ring When the motor rotates once, the linear Hall sensor induces a continuous signal through the magnetic field strength of the magnetic sheet or magnetic ring.
The speed control system according to any one of claims 4-5, wherein the distance between adjacent Hall sensors is a preset distance.
The speed control system according to claim 1, wherein the control module comprises: a main control unit and a power drive circuit;

The output terminal of the main control unit is electrically connected with the power drive circuit, the power drive circuit is used to drive the motor to rotate in one direction, and the main control unit is signally connected with the induction module;

When the power drive circuit controls the one-way rotation of the motor, the main control unit provides the power drive circuit with a target drive effective voltage corresponding to the signal to control the motor according to the signal fed back by the induction module , So that in the one-way movement of the motor, the effective voltage is driven by the target corresponding to each group of signals to drive the motor, thereby adjusting the moving speed of the wiper.
The speed control system according to claim 8, wherein the power drive circuit comprises any combination of the following:

The combination of PMOS and NMOS, in which the motor high-side drive is used, and the reserved sampling resistor is set at the lower end of the motor. When the motor is working normally, the low-side MOS and the high-side MOS are turned on in opposite phases, and the high-side MOS is turned off when the motor stops. And turn on the low-side MOS to provide braking force for the motor;

Combination of PMOS and NMOS, in which the motor low-side drive is adopted, and the reserved sampling resistor is set at the lower end of the low-side MOS. When the motor is working normally, the high-side MOS and the low-side MOS are turned on in opposite phases, and the low-side is turned off when the motor stops. MOS, and turn on high-side MOS to provide braking force for the motor;

The combination of NMOS and NMOS, in which the high-side motor is driven, and the reserved sampling resistor is set at the lower end of the motor. When the motor is working normally, the low-side MOS and the high-side MOS are turned on in opposite phases, and the high-side MOS is turned off when the motor stops. And turn on the low-side MOS to provide braking force for the motor;

NMOS and NMOS combination, in which the motor low-side drive is adopted, and the reserved sampling resistor is set at the lower end of the low-side MOS. When the motor works normally, the high-side MOS and the low-side MOS are turned on in opposite phases, and the low-side is turned off when the motor stops. MOS, and turn on the high-side MOS to provide braking force for the motor.
8. The speed control system according to claim 8, wherein the main control unit includes a main control MCU and a driving circuit;

The main control MCU is coupled to the input end of the drive circuit, the output end of the drive circuit is coupled to the input end of the power drive circuit, and the main control MCU is also signally connected to the sensing module. The master control MCU provides the driving circuit with a duty ratio of the target driving effective voltage corresponding to the signal, and the driving circuit drives the power driving circuit based on the duty ratio.
The speed control system according to claim 10, wherein the main control unit further comprises an amplifier, an input end of the amplifier is coupled to the power drive circuit, and an output end of the amplifier is coupled to the main Control the MCU so that the main control MCU, the drive circuit, the power drive circuit, and the amplifier form a closed loop control, and the main control MCU controls the output to the drive circuit according to the sampled electrical signal of the power drive circuit fed back by the amplifier The duty cycle.
The speed control system according to claim 11, wherein the main control unit further comprises a power supply module, and the power supply module is used for supplying power to the main control MCU and to the induction module.
The speed control system according to any one of claims 8-12, wherein at least one of the components of the main control unit is a discrete structure.
The speed control system according to any one of claims 8-12, wherein the main control unit is an integrated integrated circuit chip, and each component of the main control unit is integrated on the integrated circuit chip .
The speed regulation control system of claim 12, wherein the control module further comprises an anti-reverse connection circuit, and the output end of the anti-reverse connection circuit is coupled to the power supply module to prevent the main control The unit is reversed.
The speed control system according to claim 12, wherein the control module further comprises a filter circuit, one end of the filter circuit is coupled to the power module, and the other end is coupled to the power drive circuit, and the filter circuit is The circuit is used to supply power to the power drive circuit, and is also used to suppress external emission of the PWM drive waveform of the power drive circuit.
The speed control system according to claim 10, wherein the control module further comprises a temperature sensor, and the temperature sensor is coupled with the main control MCU.