CN215267623U - Overcurrent protection circuit of three-phase brushless direct current motor - Google Patents
Overcurrent protection circuit of three-phase brushless direct current motor Download PDFInfo
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- CN215267623U CN215267623U CN202121247675.8U CN202121247675U CN215267623U CN 215267623 U CN215267623 U CN 215267623U CN 202121247675 U CN202121247675 U CN 202121247675U CN 215267623 U CN215267623 U CN 215267623U
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Abstract
The utility model relates to an overcurrent protection circuit, in particular to an overcurrent protection circuit of a three-phase brushless DC motor, which can be simultaneously applied to the conditions of motor stalling and overload, when the motor is in an overload working state, the working current of the motor can be reduced by adjusting the duty ratio of a PWM signal, and the maximum power can be still output according to the load condition on the premise of not damaging a driving module; the duty ratio of the PWM signal can be adjusted to effectively adjust the reference voltage in the comparison module, so that the overcurrent protection circuit can be suitable for different driving modules and brushless direct current motors, and convenience is brought to subsequent upgrading and updating; the utility model provides a technical scheme can effectively overcome the defect that prior art exists can not effectively adjust, motor load can't output torque when too big to the reference voltage in the voltage comparison module.
Description
Technical Field
The utility model relates to an overcurrent protection circuit, concretely relates to three-phase brushless DC motor's overcurrent protection circuit.
Background
Brushless DC motor mainly comprises motor main part and drive module, uses electronic switch to replace traditional commutator, does not have spark, radio interference, noise etc. during the switching-over, does not have wearing and tearing and long service life for brushless DC motor is used by all trades, for example: fan in the sleep breathing machine.
However, the conventional brushless dc motor does not have an automatic overcurrent protection function. Taking a fan in a sleep respirator as an example, when foreign matters enter the fan, the output power of the fan is increased and the phase current is increased under the same PID algorithm because the pressure of an air outlet is controlled to be constant; the blower can be blocked, the brushless direct current motor cannot convert electric energy into kinetic energy, the phase current of the brushless direct current motor only depends on the phase resistance, and the phase current is very large. In both cases, the phase current is increased, which increases the heat productivity of the driving chip and the driving switch tube, and if the driving chip and the driving switch tube are not controlled, the driving chip and the driving switch tube are burned out.
In the prior art, a voltage sampled by a voltage is compared with a reference voltage of a voltage comparison module, a control signal is output to control an overcurrent protection circuit, and the overcurrent protection circuit controls the output of a driving module to be closed.
The above prior art has the following disadvantages: 1) after the model of the driving switch tube or the model of the motor is changed, the reference voltage in the voltage comparison module needs to be adapted again, and hardware is very troublesome to change; 2) if the load of the motor is too large, the driving module is directly closed, and the torque cannot be output.
SUMMERY OF THE UTILITY MODEL
Technical problem to be solved
To the above shortcoming that prior art exists, the utility model provides a three-phase brushless DC motor's overcurrent protection circuit can effectively overcome the defect that prior art exists can not effectively adjust, motor load can't output torque when too big to the reference voltage in the voltage comparison module.
(II) technical scheme
In order to achieve the above purpose, the utility model discloses a following technical scheme realizes:
an overcurrent protection circuit for three-phase brushless DC motor comprises
The driving module is connected with the control unit and used for driving the motor and sending a Hall signal to the control unit;
the current sampling circuit is connected with the driving module and is used for converting a current signal generated when the motor works into a voltage signal and inputting the voltage signal into the amplifying module and the comparing module;
the amplifying module is used for amplifying the voltage signal and inputting the amplified voltage signal into the control unit;
the comparison module is used for converting the PWM signal sent by the control unit into a reference voltage and sending a comparison result of the reference voltage and the voltage signal to the control unit;
and the control unit is used for judging the current working state of the motor according to the Hall signal, the amplified voltage signal and the comparison result of the comparison module, and switching the working state of the motor by the driving module and adjusting the duty ratio of the PWM signal.
Preferably, the amplifying module includes a non-inverting amplifier U2, a non-inverting input terminal of the non-inverting amplifier U2 receives the voltage signal ISUM, an inverting input terminal of the non-inverting amplifier U2 is connected to an output terminal, and an output terminal of the non-inverting amplifier U2 inputs the amplified voltage signal VSUM to the control unit U3.
Preferably, the amplifying module further comprises a voltage follower circuit for providing a bias voltage, the voltage follower circuit comprises a voltage follower U4, the non-inverting input terminal of the voltage follower U4 is connected to the voltage dividing resistors R10 and R11, the inverting input terminal of the voltage follower U4 is connected to the output terminal, and the output terminal of the voltage follower U4 is connected to the inverting input terminal of the non-inverting amplifier U2.
Preferably, the comparison module includes a voltage comparator U1, a non-inverting input terminal of the voltage comparator U1 is connected to the PWM signal sent by the control unit U3 through a low-pass filter, an inverting input terminal of the voltage comparator U1 is connected to the voltage signal ISUM, and an output terminal of the voltage comparator U1 is connected to the control unit U3.
Preferably, the low-pass filter comprises an RC low-pass filter consisting of a resistor R2 and a capacitor C1.
Preferably, a pull-up resistor R1 and a current limiting resistor R4 are connected between the output end of the voltage comparator U1 and the control unit U3.
Preferably, the current sampling circuit comprises a resistor R3 connected with the three-phase output end of the driving module.
Preferably, a hall signal circuit in the driving module is connected with a PWM signal input terminal of the control unit U3 and a hall sensor in the motor, and a PWM signal output terminal of the control unit U3 is connected with an input control terminal of a three-phase inverter circuit in the driving module.
(III) advantageous effects
Compared with the prior art, the overcurrent protection circuit of the three-phase brushless direct current motor can be simultaneously applied to the conditions of motor stalling and overload, when the motor is in an overload working state, the working current of the motor can be reduced by adjusting the duty ratio of the PWM signal, and the maximum power can be still output according to the load condition on the premise of not damaging the driving module; the duty ratio of the PWM signal can be adjusted to effectively adjust the reference voltage in the comparison module, so that the overcurrent protection circuit can be suitable for different driving modules and brushless direct current motors, and convenience is brought to subsequent upgrading and updating.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
Fig. 1 is a schematic connection diagram of circuit modules in the present invention;
fig. 2 is a schematic diagram illustrating a specific circuit connection of the circuit modules in fig. 1 according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the drawings in the embodiments of the present invention are combined below to clearly and completely describe the technical solutions in the embodiments of the present invention. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
An overcurrent protection circuit of a three-phase brushless DC motor, as shown in fig. 1 and 2, comprises
The driving module is connected with the control unit and used for driving the motor and sending a Hall signal to the control unit;
the current sampling circuit is connected with the driving module and is used for converting a current signal generated when the motor works into a voltage signal and inputting the voltage signal into the amplifying module and the comparing module;
the amplifying module is used for amplifying the voltage signal and inputting the amplified voltage signal into the control unit;
the comparison module is used for converting the PWM signal sent by the control unit into a reference voltage and sending a comparison result of the reference voltage and the voltage signal to the control unit;
and the control unit is used for judging the current working state of the motor according to the Hall signal, the amplified voltage signal and the comparison result of the comparison module, and switching the working state of the motor by the driving module and adjusting the duty ratio of the PWM signal.
The Hall signal circuit in the driving module is connected with the PWM signal input end of the control unit U3 and the Hall sensor in the motor, and the PWM signal output end of the control unit U3 is connected with the input control end of the three-phase inverter circuit in the driving module.
As shown IN fig. 2, the 3 hall signal circuits IN the driving module are connected to the 3 input capturing channels MCU _ PWM _ IN × 3 of the control unit U3, the hall signal circuits IN the driving module are connected to the hall sensors IN the brushless dc motor, and the control unit U3 obtains the rotation speed of the motor through the change of the hall signals. And 6 paths of PWM signal output ends MCU _ PWM of the control unit are connected with the input control end of the three-phase inverter circuit in the driving module.
The current sampling circuit comprises a resistor R3 connected with the three-phase output end of the driving module.
The current of the brushless direct current motor is sampled and converted into a voltage signal ISUM through a resistor R3, the output of the current sampling circuit is divided into two paths, one path is connected with the input end of the comparison module, and the other path is connected with the input end of the amplification module.
The amplifying module comprises a non-inverting amplifier U2, a non-inverting input end of the non-inverting amplifier U2 is connected with a voltage signal ISUM, an inverting input end of the non-inverting amplifier U2 is connected with an output end, and an output end of the non-inverting amplifier U2 inputs an amplified voltage signal VSUM to the control unit U3.
The amplifying module further comprises a voltage follower circuit for providing bias voltage, the voltage follower circuit comprises a voltage follower U4, the non-inverting input end of the voltage follower U4 is connected with voltage dividing resistors R10 and R11, the inverting input end of the voltage follower U4 is connected with the output end, and the output end of the voltage follower U4 is connected with the inverting input end of a non-inverting amplifier U2.
One path of the voltage signal ISUM enters an in-phase proportional amplifying circuit which is composed of an in-phase amplifier U2, a resistor R5, a capacitor C2, a resistor R7, a resistor R8, a resistor R6, a voltage follower U4, a capacitor C3, a resistor R11 and a resistor R10.
The voltage dividing resistors R10 and R11 divide VCC voltage and then provide bias voltage for the non-inverting amplifier U2 through the voltage follower U4, the output end of the amplification module is connected with the MCU _ ADC of the control unit U3, and the control unit U3 monitors the amplified voltage signal VSUM.
The comparison module comprises a voltage comparator U1, the non-inverting input terminal of the voltage comparator U1 is connected to the PWM signal sent by the control unit U3 through a low-pass filter, the inverting input terminal of the voltage comparator U1 is connected to the voltage signal ISUM, and the output terminal of the voltage comparator U1 is connected to the control unit U3.
The low-pass filter comprises an RC low-pass filter consisting of a resistor R2 and a capacitor C1.
A pull-up resistor R1 and a current-limiting resistor R4 are connected between the output end of the voltage comparator U1 and the control unit U3.
One path of the voltage signal ISUM is connected with the inverting input end of the voltage comparator U1, the control unit U3 outputs a PWM signal, the PWM signal is filtered into a controllable amplitude voltage signal (namely reference voltage) through a depth low-pass filter consisting of a resistor R2 and a capacitor C1, the amplitude of the controllable amplitude voltage signal depends on the duty ratio of the PWM signal, effective adjustment on the reference voltage in a comparison module can be realized by adjusting the duty ratio of the PWM signal, and the overcurrent protection circuit can be suitable for different driving modules and brushless direct current motors.
The voltage signal ISUM is compared with a reference voltage, and when the voltage signal ISUM is larger than a set value, the voltage comparator U1 outputs a low level. The output of the voltage comparator U1 is pulled up by a pull-up resistor R1, and then is connected to the MCU _ IN of the control unit U3 by a current limiting resistor R4.
In the technical scheme of the application, when the brushless direct current motor is locked, the control unit U3 stops outputting the control signal to the driving module by judging the hall signal and the amplified voltage signal VSUM, so that the driving module stops working, and the brushless direct current motor is turned off;
when the brushless direct current motor is overloaded, the control unit U3 adjusts the duty ratio of the control signal PWM by judging the Hall signal, the amplified voltage signal VSUM and the output signal of the comparison module, so that the current of the brushless direct current motor is reduced, and the motor works under the rated power to output the rated torque.
In the technical scheme of the application, the control unit U3 can adopt the STM32f103, and the driving module can adopt the IR2101 pre-driving module.
The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.
Claims (8)
1. The utility model provides a three-phase brushless DC motor's overcurrent protection circuit which characterized in that: comprises that
The driving module is connected with the control unit and used for driving the motor and sending a Hall signal to the control unit;
the current sampling circuit is connected with the driving module and is used for converting a current signal generated when the motor works into a voltage signal and inputting the voltage signal into the amplifying module and the comparing module;
the amplifying module is used for amplifying the voltage signal and inputting the amplified voltage signal into the control unit;
the comparison module is used for converting the PWM signal sent by the control unit into a reference voltage and sending a comparison result of the reference voltage and the voltage signal to the control unit;
and the control unit is used for judging the current working state of the motor according to the Hall signal, the amplified voltage signal and the comparison result of the comparison module, and switching the working state of the motor by the driving module and adjusting the duty ratio of the PWM signal.
2. The overcurrent protection circuit of the three-phase brushless dc motor according to claim 1, wherein: the amplifying module comprises a non-inverting amplifier U2, a non-inverting input end of the non-inverting amplifier U2 is connected with a voltage signal ISUM, an inverting input end of the non-inverting amplifier U2 is connected with an output end, and an output end of the non-inverting amplifier U2 inputs an amplified voltage signal VSUM to the control unit U3.
3. The overcurrent protection circuit of the three-phase brushless dc motor according to claim 2, wherein: the amplifying module further comprises a voltage follower circuit for providing bias voltage, the voltage follower circuit comprises a voltage follower U4, the non-inverting input end of the voltage follower U4 is connected with a voltage dividing resistor R10 and a voltage dividing resistor R11, the inverting input end of the voltage follower U4 is connected with the output end, and the output end of the voltage follower U4 is connected with the inverting input end of a non-inverting amplifier U2.
4. The overcurrent protection circuit of the three-phase brushless dc motor according to claim 2, wherein: the comparison module comprises a voltage comparator U1, the non-inverting input terminal of the voltage comparator U1 is connected to the PWM signal sent by the control unit U3 through a low-pass filter, the inverting input terminal of the voltage comparator U1 is connected to the voltage signal ISUM, and the output terminal of the voltage comparator U1 is connected to the control unit U3.
5. The overcurrent protection circuit of the three-phase brushless direct-current motor according to claim 4, wherein: the low-pass filter comprises an RC low-pass filter consisting of a resistor R2 and a capacitor C1.
6. The overcurrent protection circuit of the three-phase brushless direct-current motor according to claim 4, wherein: and a pull-up resistor R1 and a current-limiting resistor R4 are connected between the output end of the voltage comparator U1 and the control unit U3.
7. The overcurrent protection circuit of the three-phase brushless direct-current motor according to claim 2 or 4, wherein: the current sampling circuit comprises a resistor R3 connected with the three-phase output end of the driving module.
8. The overcurrent protection circuit of the three-phase brushless dc motor according to claim 7, wherein: the Hall signal circuit in the driving module is connected with the PWM signal input end of the control unit U3 and the Hall sensor in the motor, and the PWM signal output end of the control unit U3 is connected with the input control end of the three-phase inverter circuit in the driving module.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121247675.8U CN215267623U (en) | 2021-06-04 | 2021-06-04 | Overcurrent protection circuit of three-phase brushless direct current motor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121247675.8U CN215267623U (en) | 2021-06-04 | 2021-06-04 | Overcurrent protection circuit of three-phase brushless direct current motor |
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| CN215267623U true CN215267623U (en) | 2021-12-21 |
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| CN202121247675.8U Expired - Fee Related CN215267623U (en) | 2021-06-04 | 2021-06-04 | Overcurrent protection circuit of three-phase brushless direct current motor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115499573A (en) * | 2022-09-19 | 2022-12-20 | 杭州海康威视数字技术股份有限公司 | Video camera |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115499573A (en) * | 2022-09-19 | 2022-12-20 | 杭州海康威视数字技术股份有限公司 | Video camera |
| CN115499573B (en) * | 2022-09-19 | 2024-07-26 | 杭州海康威视数字技术股份有限公司 | Video camera |
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| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of utility model: An overcurrent protection circuit for three-phase brushless DC motor Effective date of registration: 20220530 Granted publication date: 20211221 Pledgee: Bozhou Jindi financing Company limited by guarantee Pledgor: Bozhou Lianqi Medical Technology Co.,Ltd. Registration number: Y2022980006765 |
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| PE01 | Entry into force of the registration of the contract for pledge of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20211221 |
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| CF01 | Termination of patent right due to non-payment of annual fee |