A DC motor stall detection circuit

Abstract

The present application discloses a DC motor stall detection circuit, comprising a single-chip microcomputer, a drive circuit, and a signal acquisition circuit. The single-chip microcomputer is used to output a PWM signal, and to send a stop signal at a set time interval to stop the motor for a set time, and to detect the voltage signals of the positive and negative poles of the motor after sending the stop signal; the drive circuit is connected to the single-chip microcomputer circuit, and is used to control the motor speed according to the PWM signal of the single-chip microcomputer and control the motor stall setting time according to the stop signal; the signal acquisition circuit is connected to the single-chip microcomputer circuit, and is used to respectively collect the voltage signals of the positive and negative poles of the motor when the motor stops and transmit them to the corresponding interfaces of the single-chip microcomputer respectively.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a DC motor stall detection circuit. Background Art

[0002] DC motors are electric motors that convert DC power into mechanical energy and are widely used in electric traction. Once a motor is stalled during use, if the stall lasts for a long time, the motor is likely to burn out. Existing technologies for motor protection usually detect motor temperature and current to detect whether a stall has occurred. Although both technologies can achieve a protective effect, they all have obvious lags and waste electricity. Summary of the invention

[0003] The purpose of the present application is to provide a DC motor stall detection circuit to solve the problems in the prior art.

[0004] To achieve the above purpose, the present application provides the following technical solution: a DC motor stall detection circuit, comprising:

[0005] A single chip microcomputer, used for outputting a PWM signal, and for sending a stop signal at a set time interval to stop the motor for a set time, and for detecting voltage signals of the positive and negative electrodes of the motor after sending the stop signal;

[0006] A driving circuit, connected to the single-chip microcomputer circuit, for controlling the motor speed according to the PWM signal of the single-chip microcomputer and controlling the motor stop setting time according to the stop signal;

[0007] A signal acquisition circuit, connected to the single-chip microcomputer circuit, for respectively acquiring voltage signals of the positive and negative electrodes of the motor when the motor stops rotating and transmitting them to corresponding interfaces of the single-chip microcomputer respectively;

[0008] The driving circuit includes: a first triode, a second triode, and a transistor, the base of the second triode is connected to the CCP1 port of the single-chip microcomputer, the base of the first triode is connected to the collector of the second triode, the emitter of the second triode is grounded, the collector of the first triode is connected to the positive electrode of the motor, the emitter of the first triode is connected to the gate of the transistor, the drain of the transistor is connected to the negative electrode of the motor, and the source of the transistor is grounded.

[0009] Preferably, the signal acquisition circuit includes a ninth resistor, a twelfth resistor, a tenth resistor and a thirteenth resistor, one end of the twelfth resistor is connected to the negative pole of the motor, and the other end is connected to one end of the ninth resistor and the RA0 port of the single-chip microcomputer; the other end of the ninth resistor is grounded; one end of the thirteenth resistor is connected to the positive pole of the motor, and the other end is connected to one end of the tenth resistor and the RA1 port of the single-chip microcomputer; the other end of the tenth resistor is grounded.

[0010] Preferably, the base of the second transistor is also connected to the VCC port of the single-chip microcomputer via a first resistor, and a fourth resistor is connected between the base of the second transistor and the CCP1 port of the single-chip microcomputer.

[0011] Preferably, the collector of the second transistor is connected to the cathode of the first diode, the anode of the first diode is connected to one end of the fifth resistor, the other end of the fifth resistor is electrically connected to the seventh resistor, the other end of the seventh resistor is connected to the source of the transistor and one end of the eighth resistor, and the other end of the eighth resistor is grounded.

[0012] Preferably, the driving circuit also includes: a second resistor, a first capacitor, and a third resistor; one end of the second resistor is connected to the positive electrode of the motor, and the other end is respectively connected to the collector of the second transistor, the negative electrode of the first diode and one end of the third resistor, the other end of the third resistor is connected to the base of the first transistor, and the first capacitor is connected in parallel to the third resistor.

[0013] Preferably, the driving circuit also includes: a second diode, a sixth resistor, and a third capacitor, the cathode of the second diode is connected to the anode of the motor, and the anode of the second diode is connected to the cathode of the motor; one end of the sixth resistor is connected to the emitter of the first transistor, and the other end is respectively connected to the gate of the transistor and one end of the seventh resistor and the fifth resistor, and the third capacitor is connected in parallel to the seventh resistor.

[0014] Preferably, the signal acquisition circuit further includes: a fourth capacitor and a fifth capacitor, and the fourth capacitor and the fifth capacitor are connected in parallel to the ninth resistor and the tenth resistor respectively.

[0015] Preferably, the DC motor stall detection circuit further includes a second capacitor, one end of which is connected to the VCC port of the single-chip microcomputer, and the other end of which is grounded.

[0016] Preferably, the DC motor stall detection circuit further includes a positive power supply connected to the positive pole of the motor.

[0017] Preferably, the transistor is an N-MOS transistor, and the second diode is a Schottky diode.

[0018] This DC motor stall detection circuit is used in the automotive electronic fan speed control module, adopts PWM speed control mode, and the PWM operating frequency is 20KHZ. During the adjustment process, a 5ms motor stop signal is given every 3 seconds. Since 5ms is a very short time, it will not have any effect on the operation of the motor. After the motor stops for 5ms, measure the voltage difference between the negative pole AN0 and the positive pole AN1 in the circuit. When the voltage at the positive pole AN1 is greater than the voltage at the negative pole AN0, and is greater than 150, it means there is no stall, otherwise it is stalled. This technical solution has high detection sensitivity and good energy-saving effect. It can also replace the overcurrent protection circuit, thereby reducing the design size of the PCB and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a circuit diagram of a DC motor stall detection circuit of the present application. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] See also Figure 1 , a DC motor stall detection circuit, comprising: a single-chip microcomputer U1, a drive circuit, and a signal acquisition circuit; wherein the single-chip microcomputer U1 of the present embodiment may be of the optional model MSF94F1404, which is used to output a PWM signal, and to send a stop signal for stopping the motor for a set time at a set time interval, and to detect the voltage signals of the positive and negative electrodes of the motor after sending the stop signal; here, the single-chip microcomputer U1 is usually controlled by a control program stored in the single-chip microcomputer U1 to send a stop signal for stopping the motor MG1 for a set time. In the present embodiment, the motor MG1 operates according to the PWM signal of the single-chip microcomputer U1, and during the operation, the control program stored in the single-chip microcomputer U1 causes the fifth foot of the single-chip microcomputer U1, i.e., the CCP1 port, to output a 5ms stop signal every 3 seconds, so that the motor MG1 temporarily stops rotating, and the temporary stop time is 5ms, and then resumes normal operation; it can be understood that the port of the single-chip microcomputer U1 outputting the PWM signal can be the same port as the port outputting the stop signal, that is, in the process of outputting the PWM signal, a 5ms stop signal is output every 3 seconds;

[0022] The driving circuit is connected to the single-chip computer U1 circuit, and is used to control the motor speed according to the PWM signal of the single-chip computer and control the motor stop setting time according to the stop signal;

[0023] The signal acquisition circuit is connected to the single-chip computer U1 circuit, and is used to respectively acquire the voltage signals at the positive electrode AN1 and the negative electrode AN0 of the motor MG1 when the motor MG1 stops rotating, and transmit them to the corresponding interfaces of the single-chip computer U1 respectively;

[0024] The driving circuit includes: a first transistor Q1, a second transistor Q2, and a transistor Q3. The base of the second transistor Q2 is connected to the CCP1 port of the single-chip computer, the base of the first transistor Q1 is connected to the collector of the second transistor Q2, the emitter of the second transistor Q2 is grounded, the collector of the first transistor Q1 is connected to the positive electrode of the motor MG1, the emitter of the first transistor Q1 is connected to the gate of the transistor Q3, the drain of the transistor Q3 is connected to the negative electrode of the motor MG1, and the source of the transistor Q3 is grounded.

[0025] Preferably, the signal acquisition circuit includes a ninth resistor R9, a twelfth resistor R12, a tenth resistor R10 and a thirteenth resistor R13, one end of the twelfth resistor R12 is connected to the negative electrode of the motor MG1, and the other end is connected to one end of the ninth resistor R9 and the RA0 port of the single-chip computer U1; the other end of the ninth resistor R9 is grounded; one end of the thirteenth resistor R13 is connected to the positive electrode of the motor MG1, and the other end is connected to one end of the tenth resistor R10 and the RA1 port of the single-chip computer U1; the other end of the tenth resistor R10 is grounded; the ninth resistor R9, the twelfth resistor R12, the tenth resistor R10 and the RA0 port of the single-chip computer U1 are connected to the positive electrode of the motor MG1, and the other end is connected to one end of the tenth resistor R10 and the RA1 port of the single-chip computer U1; the other end of the tenth resistor R10 is grounded; The twelfth resistor R12, the tenth resistor R10 and the thirteenth resistor R13 are all voltage-dividing resistors, wherein the ninth resistor R9 and the twelfth resistor R12 are used to obtain the voltage at the negative pole AN0 of the motor MG1, and transmit the voltage signal to the RA0 port of the microcontroller U1 to detect the voltage at the negative pole AN0 of the motor MG1 at this time, the tenth resistor R10 and the thirteenth resistor R13 are used to obtain the voltage signal at the positive pole AN1 of the motor MG1 and transmit it to the RA1 port of the microcontroller U1 to detect the voltage at the positive pole AN1 of the motor MG1 at this time.

[0026] Preferably, the base of the second transistor Q2 is also connected to the VCC port of the single-chip computer U1 through the first resistor R1, and a fourth resistor R4 is connected between the base of the second transistor Q2 and the CCP1 port of the single-chip computer U1. Through the above configuration, when power is initially turned on, the VCC port of the single-chip computer U1 provides a positive voltage of 5V to the base of the second transistor Q2 through the first resistor R1, so that the second transistor Q2 is turned on, thereby turning off the first transistor Q1, and then turning off the transistor Q3, ensuring that the motor MG1 is in a stopped state when power is initially turned on.

[0027] Preferably, the collector of the second triode Q2 is connected to the cathode of the first diode D1, the anode of the first diode D1 is connected to one end of the fifth resistor R5, the other end of the fifth resistor R5 is electrically connected to the seventh resistor R7, the other end of the seventh resistor R7 is connected to the source of the transistor Q3 and one end of the eighth resistor R8, and the other end of the eighth resistor R8 is grounded. Here, the first diode D1 adopts a switching diode to speed up the cut-off speed of the transistor Q3, reduce the heat generation of the transistor Q3, and ensure the reliability of the circuit.

[0028] Preferably, the drive circuit also includes: a second resistor R2, a first capacitor C1, and a third resistor R3; one end of the second resistor R2 is connected to the positive electrode of the motor MG1, and the other end is respectively connected to the collector of the second transistor Q2, the negative electrode of the first diode D1, and one end of the third resistor R3; the other end of the third resistor R3 is connected to the base of the first transistor Q1, and the first capacitor C1 is connected in parallel with the third resistor R3. Through the above configuration, the reliability of the drive circuit is improved through the current limiting protection of each resistor, and the purpose of setting the first capacitor C1 is to speed up the cutoff speed of the first transistor Q1 when it is cut off.

[0029] Preferably, the drive circuit also includes: a second diode D2, a sixth resistor R6, and a third capacitor C3, the cathode of the second diode D2 is connected to the anode of the motor MG1, and the anode of the second diode D2 is connected to the cathode of the motor MG1; one end of the sixth resistor R6 is connected to the emitter of the first transistor Q1, and the other end is respectively connected to the gate of the transistor Q3 and one end connected to the seventh resistor R7 and the fifth resistor R5, the third capacitor C3 is connected in parallel with the seventh resistor R7, and the reliability of the circuit is improved by the signal filtering effect of the third capacitor C3; further preferably, the transistor Q3 is an N-MOS tube and the second diode D2 is a Schottky diode, here, the second diode D2 adopts a Schottky diode, which has the function of a freewheeling diode, so that the motor MG1 runs smoothly; the significance of setting the seventh resistor R7 is to quickly cut off the transistor Q3.

[0030] Preferably, the signal acquisition circuit also includes: a fourth capacitor C4 and a fifth capacitor C5. The fourth capacitor C4 and the fifth capacitor C5 are respectively connected in parallel to the ninth resistor R9 and the tenth resistor R10. Through the signal filtering effect of the fourth capacitor C4 and the fifth capacitor C5, the anti-interference performance of the signal acquisition circuit is enhanced.

[0031] Preferably, the DC motor stall detection circuit further includes a second capacitor C2, one end of the second capacitor C2 is connected to the VCC port of the single-chip computer U1, and the other end is grounded.

[0032] Preferably, the DC motor stall detection circuit further includes a positive power supply connected to the positive pole of the motor. In this embodiment, the voltage of the positive power supply is 12V.

[0033] Combined with the attached drawings, the working principle of the DC motor stall detection circuit is that when the single-chip microcomputer U1 pin 5, that is, the CCP1 port, outputs a low level of 0, the second transistor Q2 is turned off, the first transistor Q1 is turned on, the transistor Q3 is turned on, and the motor MG1 is powered on and rotates. When the single-chip microcomputer U1 pin 5, that is, the CCP1 port, outputs a high level of 1, the second transistor Q2 is turned on, the first transistor Q1 is turned off, the transistor Q3 is turned off, and the motor MG1 is powered off and stops. At this time, due to the inductance of the internal coil of the motor MG1, a high voltage will be generated after the motor MG1 is powered off. If the coil voltage is not consumed, the transistor Q3 will be burned out. Therefore, a Schottky diode D2 is connected in parallel at both ends of the motor MG1. When the single-chip computer U1 outputs a certain PWM signal, the switching speed of the motor can be adjusted, thereby adjusting the speed of the motor. In this embodiment, the PWM operating frequency is 20KHZ; in this process, the 5th pin of the single-chip computer U1 outputs a 5ms stop signal every 3 seconds. After 5ms, the single-chip computer U1 collects the voltage signals at the negative pole AN0 and the positive pole AN1 of the motor MG1, and determines whether the motor is blocked by judging the voltage values ​​of the two points. The judgment condition is that the voltage at the positive pole AN1 is greater than the voltage at the negative pole AN0, and is greater than 150, indicating that there is no blockage, otherwise it is blocked. The detection sensitivity is high. Furthermore, when it is judged to be blocked, the single-chip computer U1 outputs a stop command to stop the motor MG1 from working, thereby effectively protecting the motor.

[0034] Since the single-chip microcomputer U1 has a memory to realize the function of storing programs, the present application can very conveniently store the control program in the single-chip microcomputer U1, with high detection sensitivity. Compared with the current or temperature detection method, it has obvious energy-saving effect because there is no hysteresis phenomenon. In addition, when the circuit has overcurrent, an effect similar to stalling will occur, that is, the voltage measured at AN1 is also lower than the voltage at AN0, and the difference between the voltage at AN1 and the voltage at AN0 will not be greater than 150. The DC motor stall detection circuit will still send a protection signal. Therefore, the DC motor stall detection circuit can also replace the overcurrent protection circuit, thereby reducing the design size of the PCB and achieving the effect of saving costs.

[0035] The following is the test data. From the test data, it can be seen that when there is no stall, the minimum difference between the voltage at AN1 and the voltage at AN0 is 383, and when there is a stall, the maximum difference between the voltage at AN1 and the voltage at AN0 is -77. To avoid misjudgment, the threshold is set to 150, that is, the voltage at the positive pole AN1 is greater than the voltage at the negative pole AN0, and is greater than 150, indicating that there is no stall, otherwise it is a stall.

[0036]

[0037]

[0038] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0039] The block diagrams of the devices, devices, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, devices, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0040] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0041] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0042] It should be understood by those skilled in the art that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may be deformed or modified in any way without departing from the principles.

Claims

1. A DC motor stall detection circuit, characterized in that: include: A single chip microcomputer, used for outputting a PWM signal, and for sending a stop signal at a set time interval to stop the motor for a set time, and for detecting voltage signals of the positive and negative electrodes of the motor after sending the stop signal; A driving circuit, connected to the single-chip microcomputer circuit, for controlling the motor speed according to the PWM signal of the single-chip microcomputer and controlling the motor stop setting time according to the stop signal; A signal acquisition circuit, connected to the single-chip microcomputer circuit, for respectively acquiring voltage signals of the positive and negative electrodes of the motor when the motor stops rotating and transmitting them to corresponding interfaces of the single-chip microcomputer respectively; The driving circuit includes: a first triode, a second triode, and a transistor, the base of the second triode is connected to the CCP1 port of the single-chip microcomputer, the base of the first triode is connected to the collector of the second triode, the emitter of the second triode is grounded, the collector of the first triode is connected to the positive electrode of the motor, the emitter of the first triode is connected to the gate of the transistor, the drain of the transistor is connected to the negative electrode of the motor, and the source of the transistor is grounded.

2. The DC motor stall detection circuit according to claim 1, characterized in that: The signal acquisition circuit includes a ninth resistor, a twelfth resistor, a tenth resistor and a thirteenth resistor, one end of the twelfth resistor is connected to the negative pole of the motor, and the other end is connected to one end of the ninth resistor and the RA0 port of the single-chip microcomputer; the other end of the ninth resistor is grounded; one end of the thirteenth resistor is connected to the positive pole of the motor, and the other end is connected to one end of the tenth resistor and the RA1 port of the single-chip microcomputer; the other end of the tenth resistor is grounded.

3. The DC motor stall detection circuit according to claim 1, characterized in that: The base of the second transistor is also connected to the VCC port of the single-chip microcomputer through the first resistor, and a fourth resistor is connected between the base of the second transistor and the CCP1 port of the single-chip microcomputer.

4. The DC motor stall detection circuit according to claim 1, characterized in that: The collector of the second transistor is connected to the cathode of the first diode, the anode of the first diode is connected to one end of the fifth resistor, the other end of the fifth resistor is electrically connected to the seventh resistor, the other end of the seventh resistor is connected to the source of the transistor and one end of the eighth resistor, and the other end of the eighth resistor is grounded.

5. The DC motor stall detection circuit according to claim 1, characterized in that: The driving circuit also includes: a second resistor, a first capacitor, and a third resistor; one end of the second resistor is connected to the positive electrode of the motor, and the other end is respectively connected to the collector of the second transistor, the negative electrode of the first diode, and one end of the third resistor, the other end of the third resistor is connected to the base of the first transistor, and the first capacitor is connected in parallel to the third resistor.

6. The DC motor stall detection circuit according to claim 4, characterized in that: The driving circuit also includes: a second diode, a sixth resistor, and a third capacitor, the cathode of the second diode is connected to the anode of the motor, and the anode of the second diode is connected to the cathode of the motor; one end of the sixth resistor is connected to the emitter of the first transistor, and the other end is respectively connected to the gate of the transistor and one end of the seventh resistor and the fifth resistor, and the third capacitor is connected in parallel to the seventh resistor.

7. The DC motor stall detection circuit according to claim 2, characterized in that: The signal acquisition circuit further includes: a fourth capacitor and a fifth capacitor, and the fourth capacitor and the fifth capacitor are connected in parallel to the ninth resistor and the tenth resistor respectively.

8. The DC motor stall detection circuit according to claim 1, characterized in that: It also includes a second capacitor, one end of which is connected to the VCC port of the single-chip computer, and the other end is grounded.

9. The DC motor stall detection circuit according to claim 2, characterized in that: Also included is a positive power source connected to the positive pole of the motor.

10. The DC motor stall detection circuit according to claim 6, characterized in that: The transistor is an N-MOS tube, and the second diode is a Schottky diode.

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