Inertia detection circuit

Abstract

The invention provides an inertia detection circuit. Wherein a first detection circuit and a second detection circuit in the inertia detection circuit form a double sampling circuit, are respectively connected with the two ends of the motor, and are used for effectively collecting the current of the motor in the stopping process of the motor, converting the current into a voltage signal and inputting the voltage signal into the controller. The controller analyzes the voltage signal, and the number of current ripples of the motor can be obtained. On the basis, according to the obtained current of the motor and the number of the current ripples, the inertia distance generated by inertia operation of the vehicle window in the stopping process of the motor can be accurately obtained.

Description

[0001] This application is a divisional application of a patent application with an application date of February 20, 2017, application number 201710090626.X, and invention name “Window Position Detection Circuit”. Technical Field

[0002] The present invention relates to the technical field of automobile control, and in particular to an inertia detection circuit. Background Art

[0003] The automatic lifting windows on the current market are mainly responsible for detecting the window position by external sensors, among which Hall sensors are the main ones. Based on the Hall effect, the Hall sensor generates an electrical signal through the relative displacement between magnetic fields, and detects the electrical signal to obtain the magnitude of the displacement to detect the window position. However, the Hall sensor requires an additional power supply to use and has weak anti-interference ability. In recent years, in order to reduce hardware costs, more and more technicians are studying sensorless window anti-pinch solutions.

[0004] Therefore, it is necessary to design a window position detection circuit that does not require an external sensor. Summary of the invention

[0005] The object of the present invention is to provide an inertia detection circuit to solve the problem of how to detect the inertia distance generated by the inertia operation of the vehicle window during the stopping process of the motor.

[0006] In order to solve the above technical problems, the present invention provides an inertia detection circuit for detecting the inertia distance of the motor-driven window inertia operation during the motor stopping process, wherein the current of the motor has ripples; the inertia detection circuit comprises: a first detection circuit, a second detection circuit and a controller, wherein:

[0007] The first detection circuit and the second detection circuit are respectively connected to two ends of the motor, and are used to collect the current of the motor during the stopping process, and output a voltage signal to the controller;

[0008] The controller analyzes the voltage signal and obtains the number of the ripples to determine the inertia distance moved by the window during the stopping process of the motor.

[0009] Optionally, in the inertia detection circuit, the motor includes a motor body, a first commutator and a second commutator, wherein:

[0010] The motor body includes a plurality of contact pieces and a plurality of resistors connected between two adjacent contact pieces, wherein the plurality of contact pieces form a commutation ring, and the commutation ring rotates when the motor rotates;

[0011] The first commutator and the second commutator are respectively located on two sides of the commutation ring, and the first commutator and the second commutator are respectively in contact with one or two contact sheets.

[0012] Optionally, in the inertia detection circuit, the inertia detection circuit further includes a first switch and a second switch, and during the stopping process of the motor,

[0013] The first switch connects the first commutator and the first detection circuit;

[0014] The second switch connects the second commutator and the second detection circuit.

[0015] Optionally, in the inertia detection circuit, the first detection circuit includes a first sampling circuit and a first filtering circuit; wherein,

[0016] The first sampling circuit is connected to the first switch and the ground, and samples the motor current to form a first voltage signal;

[0017] The first filtering circuit is connected to the first sampling circuit and filters the first voltage signal.

[0018] Optionally, in the inertia detection circuit, the first detection circuit further includes a first amplification circuit, wherein:

[0019] The first amplifying circuit is connected to the first filtering circuit and the controller, amplifies the filtered first voltage signal, and sends the amplified signal to the controller.

[0020] Optionally, in the inertia detection circuit, the second detection circuit includes a second sampling circuit and a second filtering circuit, wherein:

[0021] The second sampling circuit is connected to the second switch and the ground, and samples the motor current to form a second voltage signal;

[0022] The second filtering circuit is connected to the second sampling circuit to filter the second voltage signal.

[0023] Optionally, in the inertia detection circuit, the second detection circuit further includes a second amplification circuit, wherein:

[0024] The second amplifying circuit is connected to the second filtering circuit and the controller, amplifies the filtered second voltage signal, and sends the amplified signal to the controller.

[0025] Optionally, in the inertia detection circuit, the inertia detection circuit further includes a third amplification circuit, wherein:

[0026] The third amplifier circuit includes a positive input terminal, a negative input terminal and an output terminal, the positive input terminal is connected to the first filter circuit, the negative input terminal is connected to the second filter circuit, and the output terminal is connected to the controller.

[0027] Optionally, in the inertia detection circuit, the first filter circuit and the second filter circuit both include RC filter circuits.

[0028] Optionally, in the inertia detection circuit, the motor is a brushed DC motor.

[0029] In summary, the present invention provides an inertia detection circuit. Compared with the prior art, the first detection circuit and the second detection circuit in the inertia detection circuit constitute a double sampling circuit, and are respectively connected to the two ends of the motor, for effectively collecting the current of the motor during the motor stop process, and converting it into a voltage signal to input into the controller. The controller analyzes the voltage signal to obtain the number of current ripples of the motor. Based on this, according to the obtained current of the motor and the number of current ripples, the inertia distance generated by the inertial operation of the window during the motor stop process can be accurately obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figures 1-2 is a schematic diagram of the structure of a motor in an embodiment of the present invention;

[0031] Figure 3 is a schematic diagram of current waveforms when the motor is operating normally in an embodiment of the present invention;

[0032] Figures 4-5 is a schematic diagram of the structure of an inertia detection circuit in an embodiment of the present invention;

[0033] Figures 6 to 8 is a schematic diagram of current flow in an inertia detection circuit according to an embodiment of the present invention;

[0034] Fig. 9 is a schematic diagram of current waveforms during the process of the motor running to a complete stop in an embodiment of the present invention;

[0035] And, in the attached drawings:

[0036] 1-motor control circuit; 11-motor; 111-first commutator; 112-second commutator; 113-contact piece; 114-resistor; 12-first switch; 13-second switch; 2-first detection circuit; 21-first sampling circuit; 22-first filtering circuit; 23-first amplifying circuit; 3-second detection circuit; 31-second sampling circuit; 32-second filtering circuit; 33-second amplifying circuit; 4-controller; 5-power supply; 6-third amplifying circuit. DETAILED DESCRIPTION

[0037] The inertia detection circuit proposed by the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0038] See also Figure 4 and Figure 5 This embodiment provides an inertia detection circuit for detecting the inertia distance of the inertia of the window driven by the motor 11 when the motor 11 stops. The current of the motor 11 has ripples; and the inertia detection circuit includes: a first detection circuit 2, a second detection circuit 3 and a controller 4, wherein: the first detection circuit 2 and the second detection circuit 3 are respectively connected to the motor 11, and are used to collect the current of the motor 11 when it stops, and output a voltage signal to the controller 4; the controller 4 analyzes the voltage signal and obtains the number of ripples to determine the inertia distance of the window caused by inertia when the motor 11 stops.

[0039] It can be seen that the first detection circuit 2 and the second detection circuit 3 in the inertia detection circuit provided in this embodiment constitute a double sampling circuit, and are respectively connected to the two ends of the motor 11, and are used to effectively collect the current of the motor 11 during the stop of the motor 11, and convert it into a voltage signal and input it into the controller 4. The controller 4 analyzes the voltage signal to obtain the number of current ripples of the motor 11. Based on this, according to the obtained current of the motor 11 and the number of current ripples, the inertia distance generated by the inertial operation of the window during the stop of the motor 11 can be accurately obtained.

[0040] The following is combined with Figures 1 to 9 , specifically describe the inertia detection circuit provided in this embodiment.

[0041] See also Figures 1 to 3 The motor control circuit 1 includes a motor 11, which is used to drive the window to move, and the current of the motor 11 has ripples. And the motor 11 includes a motor body, a first commutator 111 and a second commutator 112, wherein: the motor body includes a plurality of contact pieces 113 and a plurality of resistors 114 connected between two adjacent contact pieces 113, and the plurality of contact pieces 113 form a commutation ring, and the commutation ring rotates when the motor 11 rotates; the first commutator 111 and the second commutator 112 are respectively located on both sides of the commutation ring, and the first commutator 111 and the second commutator 112 are respectively in contact with one or two contact pieces 113.

[0042] During the operation of the motor 11, the motor brushes may be in two situations: the first commutator 111 and the second commutator 112 of the motor 11 are aligned with a contact piece 113 respectively, such as Figure 1 As shown, or the first commutator 111 and the second commutator 112 of the motor 11 are respectively connected between the two contact pieces 113, as shown in FIG. Figure 2 As shown, in the two cases, the equivalent resistance of the circuit where the motor is located is different. Since the first commutator 111 and the second commutator 112 are conductors and each leads out a pin, which is switched between the power supply 5 and the first detection circuit 2 and the second detection circuit 3, respectively, it is equivalent to that the equivalent resistance between the power supply 5 and the first detection circuit 2 and the second detection circuit 3 changes, thereby causing the fluctuation of the motor current, such as Figure 3 As shown, the present invention detects the motor current fluctuation through the first detection circuit 2 and the second detection circuit 3, so as to determine the rotation trajectory and distance of the motor 11 according to the motor current detection signal, that is, to detect the window position, without the need for external sensors, saving circuit costs, and improving detection accuracy and detection reliability.

[0043] Specifically, in the inertia detection circuit, the inertia detection circuit 1 further includes a first switch 12 and a second switch 13, wherein: the first switch 12 switches the first commutator 111 between the power supply 5 or the first detection circuit 2; the second switch 13 switches the second commutator 112 between the power supply 5 or the second detection circuit 3. The first detection circuit 2 and the second detection circuit 3 can accurately detect the amount of current ripples during the operation of the motor 11, and can indirectly calculate the current window position. The anti-pinch force can also be obtained indirectly through the detection of current. When the window is pinched, the motor 11 is blocked and the amplitude of the motor current suddenly changes. The first detection circuit 2 or the second detection circuit 3 can convert the abnormal current signal into a voltage signal and send it to the controller 4. The controller 4 can calculate the anti-pinch force according to the amplitude of the voltage signal, thereby realizing a sensorless window anti-pinch solution.

[0044] like Figure 4As shown, the first detection circuit 2 includes a first sampling circuit 21, a first filtering circuit 22 and a first amplifying circuit 23, wherein: the first sampling circuit 21 is connected to the first commutator 111 and the ground, samples the motor current detection signal, and forms a first voltage signal; the first filtering circuit 22 is connected to the first commutator 111 and the first amplifying circuit 23, filters the first voltage signal; the first amplifying circuit 23 is connected to the controller 4, amplifies the filtered first voltage signal, and sends it to the controller 4. The second detection circuit 3 includes a second sampling circuit 31, a second filtering circuit 32 and a second amplifying circuit 33, wherein: the second sampling circuit 31 is connected to the second commutator 112 and the ground, samples the motor current detection signal, and forms a second voltage signal; the second filtering circuit 32 is connected to the second commutator 112 and the second amplifying circuit 33, filters the second voltage signal; the second amplifying circuit 33 is connected to the controller 4, amplifies the filtered second voltage signal, and sends it to the controller 4.

[0045] There is another solution for the first detection circuit 2 and the second detection circuit 3, such as Figure 5 As shown, the first detection circuit 2 includes a first sampling circuit 21 and a first filtering circuit 22, wherein: the first sampling circuit 21 is connected to the first commutator 111 and the ground, samples the motor current detection signal, and forms a first voltage signal; the first filtering circuit 22 is connected to the first commutator 111, and filters the first voltage signal. The second detection circuit 3 includes a second sampling circuit 31 and a second filtering circuit 32, wherein: the second sampling circuit 31 is connected to the second commutator 112 and the ground, samples the motor current detection signal, and forms a second voltage signal; the second filtering circuit 32 is connected to the second commutator 112, and filters the second voltage signal. The detection circuit also includes a third amplifier circuit 6, which can replace the first amplifier circuit 23 and the second amplifier circuit 33 to reduce the number of components, wherein: the third amplifier circuit 6 includes a positive input terminal, a negative input terminal and an output terminal, the positive input terminal is connected to the first filtering circuit 22, the negative input terminal is connected to the second filtering circuit 32, and the output terminal is connected to the controller 4.

[0046] The two groups of amplifier circuits can be replaced by an amplifier circuit composed of a single operational amplifier. The current signal processing method in the software will be different, but the timing and principle of the current flowing through the two sampling circuits are completely consistent. This technical solution can reduce one loop in the amplifier circuit, reduce the use of electronic components, save costs, and enable the detection signals of the two loops to be detected in the same amplifier, which can eliminate errors.

[0047] In addition, when the motor 11 stops, the first switch 12 and the second switch 13 switch the first commutator 111 and the second commutator 112 to the first sampling circuit 21 and the second sampling circuit 31 respectively, so that the first sampling circuit 21 and the second sampling circuit 31 form a loop with the motor 11. Due to inertia, the motor 11 does not stop at this time, and the reverse electromotive force of the motor 11 shows a tendency to suppress the inertial direction of the motor 11, thereby generating a reverse current in the first sampling circuit 21 or the second sampling circuit 31 until the motor 11 stops. The first detection circuit 2, the second detection circuit 3 and the controller 4 also detect and process the distance that the motor 11 rotates during the inertial sliding stage after the motor 11 stops, that is, the sliding distance of the window, so as to provide a more accurate sampling circuit for the sensorless window anti-pinch solution. During the stopping process of the motor 11, the inertial operation of the window driven by the motor 11 can be detected, and the motor current detection signal generated by this inertial distance can be accurately collected through the first detection circuit 2 and the second detection circuit 3. It provides a more accurate physical signal for window position calculation, which can reduce the position error caused by each window operation, reduce the failure rate of window anti-pinch function, and improve the reliability of window anti-pinch function.

[0048] Furthermore, the first sampling circuit 21 and the second sampling circuit 31 can suppress the inertial operation of the motor 11, so that the motor 11 stops faster, thereby preventing the window from continuing to move a long distance after people or objects are caught.

[0049] Specifically, the first switch 12 and the second switch 13 are relays, wherein: the common end of the relay is connected to the first commutator 111 or the second commutator 112 of the motor 11. The motor 11 is a brushed DC motor. The first detection circuit 2 and the second detection circuit 3 detect the ripple amount of the motor current detection signal.

[0050] The inertia detection circuit of the embodiment of the present invention forms a double sampling circuit. An RC filter circuit is placed behind each sampling circuit to filter out high-frequency signals in the current signal, and then amplify the filtered signal, and finally enter the controller 4 for signal acquisition. The voltage signal on each sampling circuit is restored to the motor current signal in the controller 4.

[0051] Figures 6 to 9 It is an analytical diagram of the current change during the stop process of the motor 11. Figure 6 In the figure, it is the normal operation stage before the window stops, and the current passing through the first sampling circuit 21 is the actual operating current of the motor 11. Fig. 9 The smooth current section with small ripples in Figure 7The second switch 13 switches the second commutator 112 to the second sampling circuit 31. At the instant when the contact of the second switch 13 is disconnected, the reverse electromotive force of the motor 11 will generate a spike voltage, and at this time, a spike current will be generated on the first sampling circuit 21, and the direction is the same as before the disconnection. When the contact of the second switch 13 is completely disconnected (the common end is in a suspended state), the current of the motor 11 does not have a complete loop, and the current passing through the first sampling circuit 21 becomes 0. Figure 8 Because the motor 11 has inertia, the motor 11 does not stop at this time, and the reverse electromotive force of the motor 11 shows a tendency to suppress the running direction of the motor 11 inertia, thereby generating a reverse current in the second sampling circuit 31 until the motor 11 stops, corresponding to Fig. 9 From the semicircular current peak in the graph, it can be seen that there are some ripples in this current peak, which means that the motor 11 is still rotating at this time, and the window is also driven by the inertia of the motor 11 to continue moving forward. Therefore, this current should also be sent to the controller 4 for processing to obtain a more accurate window position signal.

[0052] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. The above description is only a description of the preferred embodiments of the present invention, and is not any limitation on the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure are within the scope of protection of the claims.

Claims

1. An inertia detection circuit, used to detect the inertia distance of the motor-driven window inertia during the motor stop process, characterized in that: The electric current of the motor has ripples; The inertia detection circuit comprises: a first detection circuit, a second detection circuit and a controller, wherein: The first detection circuit and the second detection circuit are respectively connected to two ends of the motor, and are used to collect the current of the motor during the stopping process, and output a voltage signal to the controller; The controller analyzes the voltage signal and obtains the number of the ripples to determine the inertia distance moved by the window during the stopping process of the motor.

2. The inertia detection circuit according to claim 1, characterized in that: The motor comprises a motor body, a first commutator and a second commutator, wherein: The motor body includes a plurality of contact pieces and a plurality of resistors connected between two adjacent contact pieces, wherein the plurality of contact pieces form a commutation ring, and the commutation ring rotates when the motor rotates; The first commutator and the second commutator are respectively located on two sides of the commutation ring, and the first commutator and the second commutator are respectively in contact with one or two contact sheets.

3. The inertia detection circuit according to claim 2, characterized in that: The inertia detection circuit further includes a first switch and a second switch, and during the motor stopping process, The first switch connects the first commutator and the first detection circuit; The second switch connects the second commutator and the second detection circuit.

4. The inertia detection circuit according to claim 3, characterized in that: The first detection circuit includes a first sampling circuit and a first filtering circuit; wherein, The first sampling circuit is connected to the first switch and the ground, and samples the motor current to form a first voltage signal; The first filtering circuit is connected to the first sampling circuit and filters the first voltage signal.

5. The inertia detection circuit according to claim 4, characterized in that: The first detection circuit also includes a first amplification circuit, wherein: The first amplifying circuit is connected to the first filtering circuit and the controller, amplifies the filtered first voltage signal, and sends the amplified signal to the controller.

6. The inertia detection circuit according to claim 4, characterized in that: The second detection circuit includes a second sampling circuit and a second filtering circuit, wherein: The second sampling circuit is connected to the second switch and the ground, and samples the motor current to form a second voltage signal; The second filtering circuit is connected to the second sampling circuit to filter the second voltage signal.

7. The inertia detection circuit according to claim 6, characterized in that: The second detection circuit also includes a second amplification circuit, wherein: The second amplifying circuit is connected to the second filtering circuit and the controller, amplifies the filtered second voltage signal, and sends the amplified signal to the controller.

8. The inertia detection circuit according to claim 6, characterized in that: The inertia detection circuit further includes a third amplification circuit, wherein: The third amplifier circuit includes a positive input terminal, a negative input terminal and an output terminal, the positive input terminal is connected to the first filter circuit, the negative input terminal is connected to the second filter circuit, and the output terminal is connected to the controller.

9. The inertia detection circuit according to claim 6, characterized in that: The first filter circuit and the second filter circuit both include RC filter circuits.

10. The inertia detection circuit according to any one of claims 1 to 9, characterized in that: The motor is a brushed DC motor.

Images