阅读说明：本技术 一种电机控制电路、车窗控制电路及电机控制方法 (Motor control circuit, car window control circuit and motor control method ) 是由 李先平 钟锦华 邱贞荣 于 2020-12-24 设计创作，主要内容包括：本发明涉及一种电机控制电路、车窗控制电路及电机控制方法,包括驱动电路,驱动电路的输出端与继电器的受控端连接；继电器的输出端与电机的受控端连接,进而控制电机的正反转；电源开关电路,电源开关电路的输入端与供电电源连接,电源开关电路的输出端与继电器的输入端连接；控制电路,控制电路的一控制端与电源开关电路的受控端连接,进而控制电源开关电路的通断；控制电路的控制端还与驱动电路的受控端连接,进而控制的继电器开关。本方案先通过控制电路先切断继电器与供电电源之间连接,再通过控制电路控制关断继电器,进而保护继电器不被电机关断时的反向电弧破坏,适用于小型板载继电器。(The invention relates to a motor control circuit, a vehicle window control circuit and a motor control method, wherein the motor control circuit comprises a drive circuit, wherein the output end of the drive circuit is connected with the controlled end of a relay; the output end of the relay is connected with the controlled end of the motor so as to control the forward and reverse rotation of the motor; the input end of the power switch circuit is connected with a power supply, and the output end of the power switch circuit is connected with the input end of the relay; the control circuit is connected with a controlled end of the power switch circuit by a control end of the control circuit so as to control the on-off of the power switch circuit; the control end of the control circuit is also connected with the controlled end of the drive circuit so as to control the relay switch. This scheme is connected between relay and the power supply earlier through control circuit earlier, and rethread control circuit control turn-offs relay, and then reverse arc when the protection relay is not turn-offs by the motor destroys, is applicable to small-size board and carries the relay.)

1. A motor control circuit, comprising:

the output end of the driving circuit is connected with the controlled end of the relay; the output end of the relay is connected with the controlled end of the motor so as to control the forward and reverse rotation of the motor;

the input end of the power switch circuit is connected with a power supply, and the output end of the power switch circuit is connected with the input end of the relay;

the control circuit is connected with the controlled end of the power switch circuit by one control end, so that the on-off of the power switch circuit is controlled; and the control end of the control circuit is also connected with the controlled end of the drive circuit so as to control the relay switch.

2. The motor control circuit of claim 1, further comprising a current detection circuit, wherein an input terminal of the current detection circuit is connected to a detection point of the motor, and an output terminal of the current detection circuit is connected to an input terminal of the control circuit; the current detection circuit detects the current of the motor and transmits the current to the control circuit.

3. The motor control circuit according to claim 2, wherein the current detection circuit comprises a current collection circuit and a signal amplification circuit, and an output end of the current collection circuit is connected with an input end of the signal amplification circuit; the current acquisition circuit acquires the current of the motor, and transmits the current to the control circuit after filtering and amplifying through the signal amplification circuit.

4. The motor control circuit of claim 1 further comprising a timing circuit connected to an input of said control circuit; the timing circuit sends a signal to the control circuit after the control circuit cuts off the preset time of the power switch circuit.

5. The motor control circuit according to any one of claims 1 to 4, further comprising a signal detection circuit having an output connected to an input of the control circuit signal; the signal detection circuit detects and converts a lifting application signal of the motor and transmits the lifting application signal to the control circuit.

6. The motor control circuit according to any one of claims 1 to 4, wherein the number of the relays is two, and the drive circuit includes an H-bridge chip; and the controlled ends of the two relays are respectively connected with two output end pins of the H-bridge chip.

7. The motor control circuit of claim 6 wherein said relay is implemented by an on-board two-cell relay.

8. A motor control circuit according to any of claims 1 to 4 in which the power switching circuit comprises MOS switching tubes by which the connection between the relay input and the power supply is switched on or off.

9. A window control circuit, comprising: a motor, a window lift actuator and a motor control circuit as claimed in any one of claims 1 to 8; and a rotating shaft of the motor is in transmission connection with the car window lifting transmission device, and the car window is driven to lift through the car window lifting transmission.

10. A motor control method applied to the motor control circuit according to any one of claims 1 to 8, characterized by comprising the steps of:

after the motor is started to operate, when the control circuit judges that the motor needs to stop, the power switch circuit is cut off, and the on-off state of the relay is kept unchanged;

the timing time reaches a set value, or the current detection circuit detects that the current of the motor is reduced to a safe range;

and controlling the relay to be closed.

Technical Field

The invention relates to the technical field of automatic control, in particular to a motor control circuit, a vehicle window control circuit and a motor control method.

Background

The electric window of automobile drives the window lifter motor through the vehicle-mounted power supply, so that the lifter moves up and down to drive the window glass to move up and down, thereby achieving the purpose of automatic opening and closing of the window. For the drive control of the electric vehicle window, the commonly adopted scheme is to control the positive rotation and the reverse rotation of the motor through a relay H-bridge circuit so as to drive the vehicle window glass lifter to move up and down. For example, an H-bridge is an electronic circuit that inverts/reverses the voltage across a connected load or output. This type of circuit can be used for forward and reverse control of a dc motor. The H-bridge is a typical DC motor control circuit, because its circuit shape is similar to letter H, so that it is named as "H-bridge", 4 triodes form 4 vertical legs of H, and the motor is the bar in H.

At present, a socket type vehicle-mounted relay or a magnetic steel type relay with larger volume is generally adopted for controlling vehicles such as trucks, trailer vehicles, special vehicles and the like. However, the adoption of the scheme brings the following problems that (1) the price of the socket type relay is relatively high, so that the manufacturing cost of the whole vehicle is increased, and the competitiveness is reduced; (2) the socket relay is large in size and needs to be installed outside the shell, difficulty is brought to the manufacture of the whole automobile in structural planning, and meanwhile, the socket relay has the risk of loosening along with the factors of time lapse and vibration, and potential safety hazards exist; (3) the integration of automobile body control automobile electronics is hindered, the socket type relay cannot be integrated into the controller, and the trend of integration and miniaturization of the automobile body control automobile electronics is violated.

The problems can be well solved by using a small onboard relay, but for heavy vehicles such as trucks, trailer vehicles, passenger cars and special vehicles, different from cars and passenger cars using a DC12V onboard power supply, the nominal voltage of the onboard power supply of the heavy vehicle is DC24V, the highest voltage is DC36V, the current required for driving a window motor to work is relatively large, the reverse electromotive force generated at the moment of stopping the movement of a window is very high, when the onboard relay is used for driving, the fault of burning the relay often occurs, particularly when the voltage is increased to be more than 28V, the probability of burning the relay is greatly increased, the window of the vehicle cannot lift normally, and even potential safety hazards are brought. The reason for analyzing the problem is mainly because the window motor is an inductive load, and after the relay controls the window motor to stop acting, the window motor can generate reverse electromotive force, the higher the voltage is, the larger the reverse arc is, the smaller the distance between the normally open contact and the normally closed contact of the small onboard relay is, the too low voltage is born by the contacts, and the reverse electromotive force can cause the relay to be burnt out.

Disclosure of Invention

In view of the above, it is necessary to provide a motor control circuit, a window control circuit, and a motor control method, which solve the problem that a conventional small relay is easily burned by a back electromotive force when a motor is turned off.

In one aspect, the present invention provides a motor control circuit, including:

the output end of the driving circuit is connected with the controlled end of the relay; the output end of the relay is connected with the controlled end of the motor so as to control the forward and reverse rotation of the motor;

the input end of the power switch circuit is connected with a power supply, and the output end of the power switch circuit is connected with the input end of the relay;

the control circuit is connected with the controlled end of the power switch circuit by one control end, so that the on-off of the power switch circuit is controlled; and the control end of the control circuit is also connected with the controlled end of the drive circuit so as to control the relay switch.

Preferably, in order to grasp the electric energy release condition in the ground loop of the motor in time and turn off the relay according to the electric energy release condition, the motor control circuit further comprises a current detection circuit, the input end of the current detection circuit is connected with the detection point of the motor, and the output end of the current detection circuit is connected with the input end of the control circuit; the current detection circuit detects the current of the motor and transmits the current to the control circuit.

In order to conveniently acquire the current and convert the current into a signal which can be read by the controller, the current detection circuit comprises a current acquisition circuit and a signal amplification circuit, and the output end of the current acquisition circuit is connected with the input end of the signal amplification circuit; the current acquisition circuit acquires the current of the motor, and transmits the current to the control circuit after filtering and amplifying through the signal amplification circuit.

In order to judge the opportunity of movably switching off the relay, save the cost and ensure that the integration level of the circuit is higher, the motor control circuit also comprises a timing circuit connected with one input end of the control circuit; the timing circuit sends a signal to the control circuit after the control circuit cuts off the preset time of the power switch circuit.

In order to timely acquire an application signal for stopping the motor from running and judge the time for the controller to disconnect the power switch circuit, the motor control circuit further comprises a signal detection circuit of which the output end is connected with the signal input end of the control circuit; the signal detection circuit detects and converts a lifting application signal of the motor and transmits the lifting application signal to the control circuit.

Preferably, the number of the relays is two, and the driving circuit comprises an H-bridge chip; and the controlled ends of the two relays are respectively connected with two output end pins of the H-bridge chip.

Wherein, in order to save cost and make the circuit integration higher, the relay is realized by an on-board two-cell relay.

Wherein, in order to reduce the consumption, improve circuit stability, power switch circuit includes the MOS switch tube, through the MOS switch tube comes the switch-on or cuts off the connection between relay input and the power.

In another aspect, the present invention further provides a vehicle window control circuit, including: a motor, a window lift actuator and a motor control circuit as claimed in any one of claims 1 to 8; and a rotating shaft of the motor is in transmission connection with the car window lifting transmission device, and the car window is driven to lift through the car window lifting transmission.

In another aspect, the present invention further provides a motor control method applied to the motor control circuit described above, including the steps of:

after the motor is started to operate, when the control circuit judges that the motor needs to stop, the power switch circuit is cut off, and the on-off state of the relay is kept unchanged;

the timing time reaches a set value, or the current detection circuit detects that the current of the motor is reduced to a safe range;

and controlling the relay to be closed.

According to the technical scheme, when the motor needs to be stopped, the control circuit controls the cutoff relay to be connected with the power supply, after the current of the motor to the ground loop is reduced to a safe range, the control circuit controls the cutoff relay to protect the relay from being damaged by reverse electric arcs when the motor is turned off. The vehicle window relay is suitable for scenes such as a vehicle window of a large vehicle, so that the vehicle window can use a small onboard relay, the relay cannot be burnt out due to the fact that the distance between contacts of the small relay is too small, and the vehicle window relay is simple and effective.

Drawings

FIG. 1 is a schematic diagram of an embodiment of a motor control circuit of the present invention;

FIG. 2 is a schematic circuit diagram of the drive circuit, relay and power switch circuit shown in FIG. 1;

FIG. 3 is a circuit configuration diagram of the current detection circuit shown in FIG. 1;

FIG. 4 is a circuit configuration diagram of the signal detection circuit shown in FIG. 1;

fig. 5 is a flowchart illustrating steps of a motor control method according to an embodiment of the present invention.

In the drawings, the components represented by the respective reference numerals are listed below:

10. a control circuit; 20. a relay; 30. a power switching circuit; 40. a motor; 50. a current detection circuit; 60. a signal detection circuit; 70. a power supply; 80. a drive circuit.

Detailed Description

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. It is apparent that the specific details set forth in the following description are merely exemplary of the invention, which can be practiced in many other embodiments that depart from the specific details disclosed herein. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without any inventive step, are within the scope of the present invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In an embodiment, referring to fig. 1, the present invention provides a motor control circuit, including:

the output end of the driving circuit 80 is connected with the controlled end of the relay 20; the output end of the relay 20 is connected with the controlled end of the motor 40, so as to control the forward and reverse rotation of the motor 40;

the input end of the power switch circuit 30 is connected with the power supply 70, and the output end of the power switch circuit 30 is connected with the input end of the relay 20;

a control end of the control circuit 10 is connected with a controlled end of the power switch circuit 30, so as to control the on-off of the power switch circuit 30; the control terminal of the control circuit 10 is also connected to the controlled terminal of the driving circuit 80, and the relay 20 is controlled to be switched.

The technical scheme is suitable for scenes such as windows of large vehicles, the vehicle-mounted power supply used by the technical scheme is generally between DC24 and DC36, and has higher voltage compared with DC12 generally used by small buses. The motor control circuit enables the car window to use the small onboard relay 20, and the relay 20 cannot be burnt out due to the fact that the contact distance of the small relay 20 is too small, so that the motor control circuit is simple and effective.

In this embodiment, each motor 40 is controlled by two relays 20, the controlled terminals of the two relays 20 are respectively connected to an output terminal of the driving circuit 80, and the input terminals thereof are connected to the same power supply 70 through a power switch circuit 30, and respectively control the forward rotation and the reverse rotation of the motor 40.

The control circuit 10 in the present embodiment may be implemented by using, for example, chips with models MCS12G128 and S32K146 and peripheral circuits thereof, but is not limited thereto.

Referring to fig. 3, in an embodiment of the present invention, the motor control circuit further includes a current detection circuit 50, an input terminal of the current detection circuit 50 is connected to the detection point of the motor 40, and an output terminal of the current detection circuit 50 is connected to an input terminal of the control circuit 10; the current detection circuit 50 detects the magnitude of the current of the motor 40 and transmits the detected magnitude of the current to the control circuit 10. The current detection circuit 50 comprises a current acquisition circuit and a signal amplification circuit, and the output end of the current acquisition circuit is connected with the input end of the signal amplification circuit; the current acquisition circuit acquires the current of the motor 40, and transmits the current to the control circuit 10 after the current is filtered and amplified by the signal amplification circuit, so as to judge whether the current is reduced to a safe range.

The use of the current detection circuit can grasp the electric energy release condition in the ground loop of the motor 40 in time, and when the current magnitude is reduced to a safe range, the relay 20 is turned off according to the electric energy release condition. When the window motor runs, the current collection circuit collects the current of the motor 40 in real time, the current signal is converted into a voltage signal, the signal amplification circuit carries out filtering and amplification processing on the converted voltage signal, and the voltage signal is finally converted into a signal which can be accurately identified by the main MCU.

In another embodiment of the present invention, whether the current is safe or not can be predicted by a timing circuit connected to an input terminal of the control circuit 10; the timing circuit sends a signal to the control circuit 10 after a predetermined time period for the control circuit 10 to turn off the power switch circuit 30, thereby controlling the power supply to predict that the size of the motor 40 has decreased to a safe range. After the preset time for cutting off the power switch circuit 30, the relay 20 is cut off by the control circuit 10, and after the preset time, the current of the loop of the motor 40 can be attenuated to a safe range, so that the relay 20 is not damaged.

The timing circuit can be directly realized by using the MCU, the opportunity of movably switching off the relay 20 can be judged without additionally adding a circuit, the cost is saved, and the integration level of the circuit can be higher.

Referring to fig. 4, in order to timely acquire a lift application signal of the motor, the timing at which the controller controls the window to lift is determined. The motor control circuit further comprises a signal detection circuit 60 having an output connected to a signal input of the control circuit 10. The signal detection circuit 60 detects an application signal for stopping the operation of the motor 40, converts the application signal and transmits the converted signal to the control circuit 10, and the signal detection circuit 60 can detect a lifting application signal of the motor in real time and transmit the detected state to the control circuit 10 for processing and analysis.

Referring to fig. 2, in another embodiment of the present invention, the number of the relays 20 is four, and the driving circuit 80 includes an H-bridge chip; controlled ends of the four relays 20 are respectively connected with four output end pins of the H-bridge chip. Wherein, in order to practice thrift the cost, make circuit integrated level higher, relay 20 realizes through two board-mounted twin relays, and the lift of left front window is controlled to one of them twin relay, and the lift of right front window is controlled to another twin relay. In order to reduce power consumption and improve circuit stability, the power switch circuit 30 includes a MOS switch transistor, and the MOS switch transistor switches on or off the connection between the relay 20 and the power supply. The H-bridge chip may be implemented using, for example, a chip with model numbers ULN2003, DRV8838, and peripheral circuits thereof, but is not limited thereto.

It should be noted that the H-bridge chip controls the twin relay to perform different on-off combinations according to different control signals output by the control circuit 10, so as to control the motor 40 to realize forward movement and reverse movement, and further drive the car window to rise or fall.

It can be understood that the power switch circuit 30 mainly comprises a switch driving circuit 80 and a P-MOS switch circuit including a MOS switch tube, the switch driving circuit 80 is mainly used for driving the P-MOS switch circuit to be switched on and off through a small current signal, the P-MOS switch circuit controls the power supply 70 required for driving the load to operate, when the P-MOS switch circuit is switched on, the power energy required for driving the load will flow to the relay 20 through the MOS switch tube and drive the external window motor load to operate, and when the MOS switch tube is switched off, the power supply for driving the external window motor load will be cut off, and the window motor cannot operate.

In another aspect, the present invention further provides a vehicle window control circuit 10, including: the motor 40, the car window lifting transmission device and the motor control circuit are arranged; the rotating shaft of the motor 40 is connected with the car window lifting transmission device in a transmission way, and the car window is driven to lift through the car window lifting transmission.

Referring to fig. 5, the present invention further provides a motor control method applied to the above motor control circuit, including the steps of:

s10: after the motor 40 is started to operate, when the control circuit 10 judges that the motor 40 needs to stop, the power switch circuit 30 is cut off, and the switching state of the relay 20 is kept unchanged;

specifically, when the control circuit 10 determines that the motor 40 needs to stop, the control circuit 10 cuts off the connection between the relay 20 and the power supply 70 by cutting off the MOS switch tube of the power switch circuit 30, but keeps the switch state of the relay 20 on, thereby ensuring that the motor 40 continues to be conducted to the ground loop.

S20: the current of the motor 40 is detected to be reduced to a safe range through timing time reaching a set value or a current detection circuit;

specifically, the current detection circuit 50 monitors whether the current magnitude of the ground loop of the motor 40 is lower than a preset value in real time. Or by setting a predetermined time during which the current is attenuated by the safety range, it is determined that the current of the motor 40 is lower than the predetermined value when the predetermined time is reached.

S30: the control relay 20 is closed, and the ground loop of the motor 40 is cut off.

Specifically, the control circuit 10 controls the relay 20 through the driving circuit 80, and the control relay 20 cuts off the ground loop of the motor 40 to completely stop the motor 40.

According to the technical scheme, when the motor 40 needs to stop running, the control circuit 10 controls the disconnecting relay 20 to be connected with the power supply 70, after the current of the motor 40 to the ground loop is reduced to a safe range, the control circuit 10 controls the disconnecting relay 20, and therefore the relay 20 is protected from being damaged by reverse arc when the motor 40 is disconnected.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for those skilled in the art, various changes, substitutions and alterations can be made without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be subject to the claims.