CN115459218A - Direct current motor driving device and locked rotor protection method thereof - Google Patents
Direct current motor driving device and locked rotor protection method thereof Download PDFInfo
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- CN115459218A CN115459218A CN202211148263.8A CN202211148263A CN115459218A CN 115459218 A CN115459218 A CN 115459218A CN 202211148263 A CN202211148263 A CN 202211148263A CN 115459218 A CN115459218 A CN 115459218A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/0833—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors for electric motors with control arrangements
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/085—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load
- H02H7/0854—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load responsive to rate of change of current, couple or speed, e.g. anti-kickback protection
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Abstract
The invention belongs to the technical field of motor control, and discloses a direct current motor driving device and a locked rotor protection method thereof. The method comprises the following steps: when a motor starting instruction is received, the current state and the target rotating speed of the motor are obtained, when the current state is in a stop state, the locked rotor protection rotating speed is determined according to a preset rotating speed proportion and the target rotating speed, the signal duty ratio output by a modulation end is adjusted to drive the motor, then the voltage data of a sampling circuit is read, the current data of the motor is calculated, the current data is compared with a locked rotor protection current threshold value, whether the motor has a locked rotor trend or not is determined, when the motor has the locked rotor trend, potential locked rotor time is recorded, and when the potential locked rotor time is larger than or equal to the preset locked rotor time, the motor is determined to be locked, locked rotor protection is carried out, and the driving motor is stopped. Through the mode, the existing locked rotor condition of the motor before starting can be effectively protected, and the driving device is prevented from being damaged due to overlarge locked rotor current.
Description
Technical Field
The invention relates to the technical field of motor control, in particular to a direct current motor driving device and a locked rotor protection method thereof.
Background
The motor stalling is the problem that needs to pay close attention to when the motor is designed, generally needs the people to set for protect function, when the motor stalling appears, the motor needs to increase the output energy, because this energy is obtained from the electric current, the electric current will correspondingly increase, if there is not stalling protect function, will lead to the motor drive device trouble or burn out because of the electric current is too big, need in time to stop the rotation of motor and just can avoid this kind of condition to take place. However, the conventional locked-rotor protection function can only protect the locked-rotor condition after the motor is started, and under the condition that the rotating shaft of the motor is always locked-rotor, if the motor is directly operated at a target rotating speed when being started, the damage to the driving device is larger.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention mainly aims to provide a direct current motor driving device and a locked rotor protection method thereof, and aims to solve the technical problem that rotation of a rotating shaft is blocked before a motor cannot be protected by a traditional locked rotor protection function in the prior art.
In order to achieve the above object, the present invention provides a dc motor driving apparatus, comprising:
the sampling circuit comprises a motor control unit, a sampling circuit and a driving circuit, wherein a power supply end of the motor control unit is respectively connected with a power supply and an input end of a motor, a first sampling end of the motor control unit is connected with an output end of the motor, a second sampling end of the motor control unit is connected with an input end of the sampling circuit, a grounding end of the motor control unit is grounded, an input end of the sampling circuit is connected with an output end of the driving circuit, an output end of the sampling circuit is grounded, an input end of the driving circuit is connected with a modulation end of the motor control unit, and a control output end of the driving circuit is connected with an output end of the motor;
the motor control unit is used for acquiring the current state and the target rotating speed of the motor when receiving a motor starting instruction, determining a locked-rotor protection rotating speed according to a preset rotating speed proportion and the target rotating speed when the current state is a stop state, adjusting the duty ratio of a signal output by the modulation end according to the locked-rotor protection rotating speed, and controlling the opening and closing of the driving circuit so as to drive the motor;
the motor control unit is further used for reading voltage data of the sampling circuit, determining current data of the motor according to the voltage data of the sampling circuit, determining whether a locked rotor trend exists in the motor according to the current data and a locked rotor protection current threshold value, recording potential locked rotor time when the locked rotor trend exists in the motor, determining that the locked rotor occurs in the motor when the potential locked rotor time is larger than or equal to preset locked rotor time, performing locked rotor protection, and stopping driving the motor.
Optionally, the dc motor driving apparatus further includes: the motor protection circuit comprises a first filter capacitor, a freewheeling diode and a motor interface which are sequentially connected, wherein the input end of the first filter capacitor is connected with the power end of the motor control unit, the output end of the first filter capacitor is connected with the first sampling end of the motor control unit, the input end of the motor interface is connected with the input end of the motor, and the output end of the motor interface is connected with the output end of the motor.
Optionally, the dc motor driving apparatus further includes: the motor protection circuit comprises a first filter capacitor, a freewheeling diode and a motor interface which are sequentially connected, wherein the input end of the first filter capacitor is connected with the power end of the motor control unit, the output end of the first filter capacitor is connected with the first sampling end of the motor control unit, the input end of the motor interface is connected with the input end of the motor, and the output end of the motor interface is connected with the output end of the motor.
Optionally, the dc motor driving apparatus further includes: the drive protection circuit comprises a first current-limiting resistor and a pull-down resistor, wherein the input end of the first current-limiting resistor is connected with the modulation end of the motor control unit, the output end of the first current-limiting resistor is connected with the grid electrode of the drive field effect tube, the input end of the pull-down resistor is connected with the grid electrode of the drive field effect tube, and the output end of the pull-down resistor is grounded.
Optionally, the dc motor driving apparatus further includes: the sampling protection circuit comprises a second current-limiting resistor and a second filter capacitor, the output end of the second current-limiting resistor is connected with the second sampling end of the motor control unit, the input end of the second current-limiting resistor is connected with the source electrode of the driving field effect tube, the input end of the second filter capacitor is connected with the source electrode of the driving field effect tube, and the output end of the second filter capacitor is grounded.
In addition, in order to achieve the above object, the present invention further provides a locked rotor protection method for a dc motor driving device, including:
when a motor starting instruction is received, the current state and the target rotating speed of the motor are obtained;
when the current state is a stop state, determining a locked rotor protection rotating speed according to a preset rotating speed proportion and the target rotating speed, adjusting a signal duty ratio output by a modulation end according to the locked rotor protection rotating speed, and controlling the opening and closing of the driving circuit so as to drive the motor;
reading voltage data of a sampling circuit, and determining current data of the motor according to the voltage data of the sampling circuit;
determining whether the motor has a locked rotor trend according to the current data of the motor and a locked rotor protection current threshold;
recording potential locked-rotor time when the motor has a locked-rotor trend;
and when the potential locked-rotor time is more than or equal to the preset locked-rotor time, determining that the motor is locked-rotor, performing locked-rotor protection, and stopping driving the motor.
Optionally, the reading voltage data of a sampling circuit, and determining current data of the motor according to the voltage data of the sampling circuit includes:
reading voltage data of a sampling resistor in a sampling circuit;
determining current data of the sampling resistor according to the voltage data of the sampling resistor and the sampling resistor;
acquiring a corresponding relation between current data of the sampling resistor and current data of the motor;
and determining the current data of the motor according to the corresponding relation and the current data of the sampling resistor.
Optionally, the determining whether the motor has a locked rotor trend according to the current data of the motor and a locked rotor protection current threshold includes:
comparing the current data of the motor with a locked rotor protection current threshold value;
and when the current data is larger than the locked-rotor protection current threshold value, determining that the motor has a locked-rotor trend.
Optionally, when the current data is less than or equal to a locked-rotor protection current threshold, it is determined that the motor has no locked-rotor tendency, the duty ratio of the signal output by the modulation port is adjusted according to the target rotation speed, and the locked-rotor protection rotation speed is released to the target rotation speed.
Optionally, when the current state is a start state, the motor is driven according to the target rotation speed.
The method comprises the steps of obtaining the current state and the target rotating speed of a motor when a motor starting instruction is received, determining locked-rotor protection rotating speed according to a preset rotating speed proportion and the target rotating speed when the current state is in a stop state, adjusting the duty ratio of a signal output by a modulation end according to the locked-rotor protection rotating speed, controlling the opening and closing of a driving circuit to drive the motor, reading voltage data of a sampling circuit, determining the current data of the motor according to the obtained voltage data, comparing the current data with a locked-rotor protection current threshold value, determining whether the motor has a locked-rotor trend, recording potential locked-rotor time when the motor has the locked-rotor trend, determining that the motor is locked-rotor when the potential locked-rotor time is larger than or equal to the preset locked-rotor time, performing locked-rotor protection, and stopping driving the motor. Compared with the prior art which only can protect the locked-rotor condition after the motor is started, the method provided by the invention has the advantages that the motor is firstly operated at a low speed lower than the target rotating speed when the motor is started, the rotating speed is released to the target rotating speed when the motor current does not exceed the locked-rotor current, the motor is stopped when the current at the starting moment exceeds the locked-rotor current, whether the current exceeds the locked-rotor current or not can be continuously detected when the motor is operated according to the target rotating speed, the locked-rotor condition after the motor is started can be protected, the condition that the rotation of the rotating shaft of the motor is blocked before the motor is started can be effectively protected, and the damage to a motor driving device caused by the overlarge locked-rotor current is avoided.
Drawings
Fig. 1 is a block diagram showing the construction of a first embodiment of a dc motor driving apparatus according to the present invention;
fig. 2 is a schematic circuit diagram of a first embodiment of the dc motor driving apparatus of the present invention;
fig. 3 is a block diagram showing the construction of a second embodiment of the dc motor driving apparatus of the present invention;
fig. 4 is a schematic circuit diagram of a second embodiment of the dc motor driving apparatus of the present invention;
fig. 5 is a schematic flow chart of a locked-rotor protection method for a dc motor driving apparatus according to a first embodiment of the present invention;
fig. 6 is a schematic diagram illustrating motor current calculation according to an embodiment of a locked rotor protection method for a dc motor driving apparatus according to the present invention;
fig. 7 is a schematic flow chart illustrating a locked-rotor protection method for a dc motor driving device according to a second embodiment of the present invention;
fig. 8 is a schematic view of an overall locked-rotor protection process according to an embodiment of the locked-rotor protection method for the dc motor driving device of the present invention.
The reference numbers illustrate:
| reference numerals | Name(s) | Reference numerals | Name (R) | |
| 10 | |
502 | Pull- |
|
| 20 | |
601 | Second current limiting |
|
| 30 | |
602 | |
|
| 40 | Motor protection circuit | VCC | |
|
| 50 | Drive protection circuit | AD1 | A |
|
| 60 | Sampling protection circuit | | Modulation terminal | |
| 201 | Sampling resistor | AD2 | |
|
| 301 | Driving field effect tube | | Grounding terminal | |
| 401 | First filter capacitor | | Grid electrode | |
| 402 | Freewheeling diode | | Drain electrode | |
| 403 | Motor interface | S | Source electrode | |
| 501 | A first current limiting resistor |
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that all the directional indicators (such as upper, lower, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a block diagram illustrating a dc motor driving apparatus according to a first embodiment of the present invention. The present invention proposes a first embodiment of a direct current motor drive device.
As shown in fig. 1, in the present embodiment, the dc motor driving apparatus includes: motor control unit 10, sampling circuit 20 and drive circuit 30, the power end VCC of motor control unit 10 is connected with the input of power and motor respectively, the first sample terminal AD1 of motor control unit 10 is connected with the output of motor, the second sample terminal AD2 of motor control unit 10 with sampling circuit 20's input is connected, motor control unit 10's earthing terminal GND ground connection, sampling circuit 20's input with drive circuit 30's output is connected, sampling circuit 20's output ground connection, drive circuit 30's input with motor control unit 10's modulation end PWM connects, drive circuit 30's control output with the output of motor is connected.
It can be understood that the motor control unit 10 includes a power supply terminal VCC, a first sampling terminal AD1, a modulation terminal PWM, a second sampling terminal AD2, and a ground terminal GND, and the motor is a dc motor.
It should be noted that the sampling circuit 20 is configured to provide a voltage of the sampling circuit to the motor control unit 10. The driving circuit 30 is used for controlling whether the motor is electrified to work, the motor is electrified when the driving circuit 30 is started, the rotating speed of the motor is increased, the motor is powered off when the driving circuit 30 is closed, and the rotating speed of the motor is reduced.
In a specific implementation, the motor control unit 10 is configured to output a control signal using a modulation terminal PWM, control the driving circuit 30 to turn on and off to drive or stop the motor, and adjust the motor speed by adjusting a duty ratio of the control signal. The motor control unit 10 is also configured to read the voltage provided by the sampling circuit 20, calculate the motor current, determine whether a locked rotor occurs, and perform corresponding locked rotor protection during locked rotor.
Further, as shown in the schematic circuit diagram of the first embodiment shown in fig. 2, the driving circuit 30 includes a driving fet 301, a gate G of the driving fet 301 is connected to the modulation terminal PWM of the motor control unit, a source S of the driving fet 301 is connected to the input terminal of the sampling circuit 20, a drain D of the driving fet 301 is connected to the output terminal of the motor, the sampling circuit 20 includes a sampling resistor 201, an input terminal of the sampling resistor 201 is connected to the source S of the driving fet 301, and an output terminal of the sampling resistor 201 is grounded.
In this embodiment, the motor is driven at a locked-rotor protection rotation speed lower than the target rotation speed through the motor control unit 10 when the motor is started, the motor current is calculated according to the voltage of the sampling circuit, when the motor current does not exceed the locked-rotor current, the rotation speed is released to the target rotation speed, when the starting instantaneous current exceeds the locked-rotor current, the motor is stopped, the rotation of the rotating shaft of the motor before the motor is started can be effectively protected, and the motor driving device is prevented from being damaged due to the overlarge locked-rotor current.
Referring to fig. 3, fig. 3 is a block diagram of a dc motor driving apparatus according to a second embodiment of the present invention.
Based on the first embodiment, the dc motor driving apparatus of this embodiment further includes: a motor protection circuit 40, a drive protection circuit 50, and a sampling protection circuit 60.
As shown in the schematic circuit diagram of the second embodiment shown in fig. 4, the motor protection circuit 40 includes a first filter capacitor 401, a freewheeling diode 402, and a motor interface 403, which are sequentially connected, an input end of the first filter capacitor 401 is connected to the power supply terminal VCC of the motor control unit 10, an output end of the first filter capacitor 401 is connected to the first sampling terminal AD1 of the motor control unit 10, an input end of the motor interface 403 is connected to the input end of the motor, and an output end of the motor interface 403 is connected to the output end of the motor. The driving protection circuit comprises 50 first current limiting resistors 501 and pull-down resistors 502, wherein the input end of the first current limiting resistor 501 is connected with the modulation end PWM of the motor control unit 10, the output end of the first current limiting resistor 501 is connected with the grid G of the driving field effect tube 301, the input end of the pull-down resistor 502 is connected with the grid G of the driving field effect tube 301, and the output end of the pull-down resistor 502 is grounded. The sampling protection circuit 60 includes a second current-limiting resistor 601 and a second filter capacitor 602, an output end of the second current-limiting resistor 601 is connected to a second sampling end AD2 of the motor control unit 10, an input end of the second current-limiting resistor 601 is connected to the source S of the driving fet 301, an input end of the second filter capacitor 602 is connected to the source S of the driving fet 301, and an output end of the second filter capacitor 602 is grounded.
Understandably, the freewheeling diode 402 is used for preventing the motor from generating current sudden change caused by blocking, the motor interface 403 is used for providing the voltage at two ends of the motor to the motor control unit, the first current limiting resistor 501 is used for limiting the current and protecting the modulation end PWM of the motor control unit 10, the pull-down resistor 502 is used for ensuring the modulation end of the motor control unit 10 to output a low level when the motor stops, the second current limiting resistor 601 is used for limiting the current and protecting the second sampling end AD2 of the motor control unit 10, and the first filter capacitor 401 and the second filter capacitor 602 are used for removing interference clutter.
In this embodiment, the motor protection circuit 40, the driving protection circuit 50, and the sampling protection circuit 60 are used to protect the loop in the motor driving device and the port of the motor control unit 10, so as to prevent the motor from sudden change of current caused by the blocking, and further avoid the damage to the motor driving device due to the excessive blocking current.
Referring to fig. 5, fig. 5 is a schematic flow chart of a locked-rotor protection method for a dc motor driving device according to a first embodiment of the present invention.
Based on the first embodiment and the second embodiment, the invention provides a locked-rotor protection method for a direct current motor driving device.
In this embodiment, the locked rotor protection method for the dc motor driving apparatus includes:
step S10: and when a motor starting instruction is received, acquiring the current state and the target rotating speed of the motor.
It should be noted that, the execution main body of this embodiment is a Motor Control Unit (MCU), and may be any MCU which has an AD port and a PWM port and whose standby power consumption is lower than 1 uA.
It can be understood that the motor is a direct current motor, the motor starting command is obtained by operating a switch button by a user, the motor is started by operating the switch button by the user, the motor starting command is received by the MCU, the motor is turned off by operating the switch button, the motor stopping command is received by the MCU, the current state of the motor is the current state of the motor, which includes a starting state and a stopping state, the target rotation speed is the rotation speed that the motor needs to reach, which is usually preset, and the user can select a corresponding rotation speed gear when starting the motor.
In specific implementation, when a user operates to start the motor, the MCU receives a motor starting command, acquires the current state and the target rotating speed of the motor, and is used for judging whether the motor is locked, and driving the motor at a proper rotating speed.
Step S20: and when the current state is a stop state, determining a locked rotor protection rotating speed according to a preset rotating speed proportion and the target rotating speed, adjusting the duty ratio of a signal output by a modulation end according to the locked rotor protection rotating speed, and controlling the opening and closing of the driving circuit so as to drive the motor.
It should be noted that the preset rotating speed ratio is an optimal value adjusted according to a real engineering object, and is in a range of about 1/2 to 2/3, and the locked rotor protection rotating speed is a rotating speed lower than the target rotating speed.
It should be understood that the modulation end of the MCU outputs a control signal, and the on/off of the driving circuit can be controlled by adjusting the duty ratio of the control signal, and the driving circuit is used as a switch to control whether the motor is on, when the motor is on, the rotation speed of the motor is increased, and when the motor is off, the rotation speed of the motor is decreased, so as to drive the motor, stop the motor, and adjust the rotation speed of the motor.
In a specific implementation, if the current state of the motor is a stopped state, which means that the motor is started from the stopped state at this time, a situation that the motor is locked before being started may occur, and in order to avoid damage to the driving device, in this embodiment, the motor is driven at a low speed of 1/2 to 2/3 of the target rotation speed, so as to instantaneously cope with a situation that the rotating shaft is blocked before the motor is started.
Step S30: and reading voltage data of a sampling circuit, and determining the current data of the motor according to the voltage data of the sampling circuit.
Further, the step S30 includes: the method comprises the steps of reading voltage data of a sampling resistor in a sampling circuit, determining current data of the sampling resistor according to the voltage data of the sampling resistor and the sampling resistor, obtaining a corresponding relation between the current data of the sampling resistor and current data of a motor, and determining the current data of the motor according to the corresponding relation and the current data of the sampling resistor.
It can be understood that the voltage data of the sampling resistor is the voltage at two ends of the sampling resistor, the current data of the sampling resistor is the current passing through the sampling resistor, the current data of the motor is the real-time current of the motor, and the corresponding relation is a calculation relation of the current data.
In a specific implementation, as shown in a schematic diagram of calculating current of a motor shown in fig. 6, since the motor, the driving fet and the sampling resistor are connected in series, a current passing through the sampling resistor is equal to a current of the motor, and a current of the sampling resistor is calculated according to a voltage at two ends of the sampling resistor and a resistance of the sampling resistor itself, that is, a current of the motor.
Step S40: and determining whether the motor has a locked rotor trend or not according to the current data of the motor and the locked rotor protection current threshold value.
The step S40 includes: comparing the current data of the motor with a locked rotor protection current threshold value, and determining that the motor has a locked rotor trend when the current data is greater than the locked rotor protection current threshold value.
It should be noted that the locked-rotor protection current threshold is a current threshold when a locked-rotor condition occurs, and is usually set in advance, and the locked-rotor tendency is a possibility of locked-rotor of the motor.
In specific implementation, the MCU calculates the current of the motor in real time, compares the current with the locked rotor protection current threshold, and determines that the motor has a locked rotor tendency when the current data is larger than the locked rotor protection current threshold and the motor current is not in a normal range.
Further, when the current data is smaller than or equal to a locked-rotor protection current threshold value, it is determined that the motor has no locked-rotor tendency, the duty ratio of the signal output by the modulation port is adjusted according to the target rotating speed, and the locked-rotor protection rotating speed is released to the target rotating speed.
In specific implementation, if the current data is less than or equal to the locked-rotor protection current threshold value, the current of the motor is in a normal range, the motor is considered to have no locked-rotor possibility, and the rotating speed is released to the target rotating speed. In-process to the target rotational speed is released to the locked-rotor protection rotational speed, if the time that needs is overlength, the people ear can perceive the motor accelerating, influences user experience, consequently, sets up shorter time usually, is difficult to be perceived by the user to promote user experience.
Step S50: and recording potential locked-rotor time when the motor has a locked-rotor trend.
It is understood that the potential stall time is the time at which a stall tendency exists, i.e., the duration of time that the motor current exceeds the stall protection current threshold.
Step S60: and when the potential locked-rotor time is more than or equal to the preset locked-rotor time, determining that the motor is locked-rotor, performing locked-rotor protection, and stopping driving the motor.
It should be understood that the preset locked-rotor time is a preset time threshold value for determining whether the locked-rotor trend of the motor continuously exists, for example: 2s, or other values, which is not limited in this embodiment and can be flexibly adjusted according to actual situations.
In specific implementation, when the time of the locked-rotor trend is greater than the threshold, it is indicated that the motor current continuously exceeds the locked-rotor protection current threshold within the preset locked-rotor time, it is determined that locked-rotor occurs in the motor at the time, and the motor is stopped to be driven for locked-rotor protection.
In this embodiment, when a motor start instruction is received, a current state and a target rotation speed of a motor are obtained, when the current state is a stop state, a locked rotor protection rotation speed is determined according to a preset rotation speed ratio and the target rotation speed, a signal duty ratio output by a modulation end is adjusted according to the locked rotor protection rotation speed, a driving circuit is controlled to be turned on and off to drive the motor, voltage data of a sampling circuit is read, current data of the motor is determined according to the obtained voltage data, a locked rotor protection current threshold value is compared with the current data, whether a locked rotor trend exists in the motor is determined, when the locked rotor trend exists in the motor, potential locked rotor time is recorded, when the potential locked rotor time is greater than or equal to the preset locked rotor time, locked rotor is determined to occur in the motor, locked rotor protection is performed, and the motor is stopped. This embodiment is earlier with the low-speed operation that is less than target rotational speed when the motor starts, then the rotational speed is released to target rotational speed when motor current does not exceed the locked-rotor current, then stops motor work when starting the electric current in the twinkling of an eye and surpasss the locked-rotor current, has had the pivot rotation to block the condition before the motor starts and also can carry out effectual protection, avoids destroying motor drive because of locked-rotor current is too big.
Referring to fig. 7, fig. 7 is a schematic flowchart illustrating a locked-rotor protection method for a dc motor driving device according to a second embodiment of the present invention.
Based on the third embodiment, after step S10, the method for protecting a locked rotor of a dc motor driving device further includes:
step S201: and when the current state is a starting state, driving the motor according to the target rotating speed.
It can be understood that when the current state of the motor is the starting state, the rotating shaft of the motor still rotates at a certain speed at the moment, and the current of the motor is not detected to exceed the locked-rotor protection current threshold, so that the motor is considered to have no locked-rotor tendency and is directly driven at the target rotating speed.
As shown in the overall locked rotor protection flow diagram of fig. 8, when receiving a motor start instruction, the MCU first determines whether the motor is started from a stopped state, and if the motor is started from the stopped state, drives the motor at a low speed lower than a target rotation speed, reads the voltage of the sampling resistor in real time, calculates the motor current, determines whether the motor current exceeds a locked rotor protection current threshold, if so, performs locked rotor protection, stops driving the motor, and if not, releases the motor to the target rotation speed; and if the motor is not started from the stop state, directly driving the motor at the target rotating speed, similarly judging whether the motor current exceeds a locked rotor protection current threshold value in real time, carrying out locked rotor protection when locked rotor occurs, and stopping driving the motor.
In this embodiment, the motor also can constantly detect whether the electric current exceeds the locked-rotor current according to target rotational speed during operation, not only protects the motor before the motor starts the pivot rotation obstructed condition, also can carry out effectual protection to the locked-rotor condition appearing after the motor starts, further avoids damaging motor drive arrangement because of the too big locked-rotor current.
It should be understood that the above is only an example, and the technical solution of the present invention is not limited in any way, and in a specific application, a person skilled in the art may set the technical solution as needed, and the present invention is not limited thereto.
It should be noted that the above-mentioned work flows are only illustrative and do not limit the scope of the present invention, and in practical applications, those skilled in the art may select some or all of them according to actual needs to implement the purpose of the solution of the present embodiment, and the present invention is not limited herein.
Further, it is to be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or system that comprises the element.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A direct current motor drive device, characterized by comprising: the sampling circuit comprises a motor control unit, a sampling circuit and a driving circuit, wherein a power supply end of the motor control unit is respectively connected with a power supply and an input end of a motor, a first sampling end of the motor control unit is connected with an output end of the motor, a second sampling end of the motor control unit is connected with an input end of the sampling circuit, a grounding end of the motor control unit is grounded, an input end of the sampling circuit is connected with an output end of the driving circuit, an output end of the sampling circuit is grounded, an input end of the driving circuit is connected with a modulation end of the motor control unit, and a control output end of the driving circuit is connected with an output end of the motor;
the motor control unit is used for acquiring the current state and the target rotating speed of the motor when receiving a motor starting instruction, determining a locked-rotor protection rotating speed according to a preset rotating speed proportion and the target rotating speed when the current state is a stop state, adjusting the duty ratio of a signal output by the modulation end according to the locked-rotor protection rotating speed, and controlling the opening and closing of the driving circuit so as to drive the motor;
the motor control unit is further used for reading voltage data of the sampling circuit, determining current data of the motor according to the voltage data of the sampling circuit, determining whether a locked rotor trend exists in the motor according to the current data and a locked rotor protection current threshold value, recording potential locked rotor time when the locked rotor trend exists in the motor, determining that the locked rotor occurs in the motor when the potential locked rotor time is larger than or equal to preset locked rotor time, performing locked rotor protection, and stopping driving the motor.
2. The direct current motor driving device according to claim 1, wherein the driving circuit comprises a driving fet, a gate of the driving fet is connected to the modulation terminal of the motor control unit, a source of the driving fet is connected to the input terminal of the sampling circuit, and a drain of the driving fet is connected to the output terminal of the motor;
the sampling circuit comprises a sampling resistor, the input end of the sampling resistor is connected with the source electrode of the driving field effect tube, and the output end of the sampling resistor is grounded.
3. The direct current motor drive apparatus as claimed in claim 2, further comprising: the motor protection circuit comprises a first filter capacitor, a freewheeling diode and a motor interface which are sequentially connected, wherein the input end of the first filter capacitor is connected with the power end of the motor control unit, the output end of the first filter capacitor is connected with the first sampling end of the motor control unit, the input end of the motor interface is connected with the input end of the motor, and the output end of the motor interface is connected with the output end of the motor.
4. The direct current motor drive apparatus according to claim 2, further comprising: the drive protection circuit comprises a first current-limiting resistor and a pull-down resistor, wherein the input end of the first current-limiting resistor is connected with the modulation end of the motor control unit, the output end of the first current-limiting resistor is connected with the grid electrode of the drive field effect tube, the input end of the pull-down resistor is connected with the grid electrode of the drive field effect tube, and the output end of the pull-down resistor is grounded.
5. The direct current motor drive apparatus as claimed in claim 2, further comprising: the sampling protection circuit comprises a second current-limiting resistor and a second filter capacitor, the output end of the second current-limiting resistor is connected with the second sampling end of the motor control unit, the input end of the second current-limiting resistor is connected with the source electrode of the driving field effect tube, the input end of the second filter capacitor is connected with the source electrode of the driving field effect tube, and the output end of the second filter capacitor is grounded.
6. A method for protecting a dc motor driving apparatus from a stall, applied to the dc motor driving apparatus according to any one of claims 1 to 5, the method comprising:
when a motor starting instruction is received, the current state and the target rotating speed of the motor are obtained;
when the current state is a stop state, determining a locked rotor protection rotating speed according to a preset rotating speed proportion and the target rotating speed, adjusting a signal duty ratio output by a modulation end according to the locked rotor protection rotating speed, and controlling the opening and closing of the driving circuit so as to drive the motor;
reading voltage data of a sampling circuit, and determining current data of the motor according to the voltage data of the sampling circuit;
determining whether the motor has a locked rotor trend according to the current data of the motor and a locked rotor protection current threshold;
recording potential locked rotor time when the motor has a locked rotor trend;
and when the potential locked-rotor time is more than or equal to the preset locked-rotor time, determining that the motor is locked-rotor, performing locked-rotor protection, and stopping driving the motor.
7. The method of claim 6, wherein reading voltage data of a sampling circuit and determining present current data of the motor from the voltage data of the sampling circuit comprises:
reading voltage data of a sampling resistor in a sampling circuit;
determining current data of the sampling resistor according to the voltage data of the sampling resistor and the sampling resistor;
acquiring a corresponding relation between current data of the sampling resistor and current data of the motor;
and determining the current data of the motor according to the corresponding relation and the current data of the sampling resistor.
8. The method of claim 6, wherein determining whether the motor has a locked rotor trend based on the current data of the motor and a locked rotor protection current threshold comprises:
comparing the current data of the motor with a locked rotor protection current threshold;
and when the current data is larger than the locked-rotor protection current threshold value, determining that the motor has a locked-rotor trend.
9. The method of claim 6, wherein after determining whether the motor has a locked rotor trend based on the current data of the motor and a locked rotor protection current threshold, further comprising:
and when the current data is less than or equal to a locked-rotor protection current threshold value, determining that the motor has no locked-rotor tendency, adjusting the duty ratio of a signal output by the modulation port according to the target rotating speed, and releasing the locked-rotor protection rotating speed to the target rotating speed.
10. The method according to any one of claims 6 to 9, wherein after acquiring the current state of the motor upon receiving the motor start command, the method further comprises:
and when the current state is a starting state, driving the motor according to the target rotating speed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211148263.8A CN115459218A (en) | 2022-09-20 | 2022-09-20 | Direct current motor driving device and locked rotor protection method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211148263.8A CN115459218A (en) | 2022-09-20 | 2022-09-20 | Direct current motor driving device and locked rotor protection method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115459218A true CN115459218A (en) | 2022-12-09 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211148263.8A Pending CN115459218A (en) | 2022-09-20 | 2022-09-20 | Direct current motor driving device and locked rotor protection method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115459218A (en) |
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2022
- 2022-09-20 CN CN202211148263.8A patent/CN115459218A/en active Pending
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