CN109066594A - Over-temperature protection device of motor, motor and over-temperature protection method of motor - Google Patents

Abstract

The invention discloses an over-temperature protection device for a motor, a motor and an over-temperature protection method thereof. The device comprises: a thermistor for sensing the current temperature of a switching tube of the motor; The resistors are arranged in series to form a voltage division branch for the preset power supply, so as to realize the voltage division control of the voltage stabilizing unit and the control switch; In the case of the preset over-temperature protection point of the switch tube, it is in an off state, so as to control the conduction of the control switch in combination with the voltage dividing branch and output a low-level signal to the controller of the motor, so that The controller controls the motor to stop according to the low level signal. The solution of the present invention can solve the problem of poor protection reliability in the over-temperature shutdown protection by controlling the switch of the triode in the prior art, and achieve the effect of improving the protection reliability.

Description

An over-temperature protection device for a motor, a motor and an over-temperature protection method thereof

technical field

The invention belongs to the technical field of temperature protection, and in particular relates to an over-temperature protection device for a motor, a motor and an over-temperature protection method thereof, in particular to a high-precision over-temperature protection circuit, a motor with the over-temperature protection circuit, and the motor over-temperature protection method.

Background technique

Because the brushless DC motor has the characteristics of high efficiency, large starting torque, and convenient control, its application fields are becoming wider and wider. The brushless DC motor is mainly composed of two parts: the motor body and the controller. The controller part includes a control chip, a power drive circuit, a position detection circuit, signal feedback and other circuits; the power drive circuit is generally composed of a signal amplifier circuit and a full-bridge (or half-bridge) inverter circuit, and the switching tube in the inverter circuit In the process of high-speed turn-on or turn-off, it will generate serious heat. Once the heat exceeds the temperature tolerance range of the switch tube, it will cause the switch tube to burn out and cause the motor to fail.

Therefore, in order to avoid the failure of the brushless DC motor due to the high temperature of the switching tube device, it is necessary to add an over-temperature protection circuit in the design of the brushless DC motor controller. Over temperature protection circuit design. The existing over-temperature protection circuit performs over-temperature shutdown protection by controlling the switch of the triode. Since the switching voltage range of the control triode is relatively large, generally 0.7V-1.0V, it may cause false protection of the motor or untimely protection.

Contents of the invention

The object of the present invention is to address the above defects, to provide an over-temperature protection device for a motor, a motor and an over-temperature protection method thereof, so as to solve the problem of poor protection reliability in the prior art by controlling the switch of the triode to perform over-temperature shutdown protection. problem, to achieve the effect of improving the reliability of protection.

The present invention provides an over-temperature protection device for a motor, comprising: a thermistor, a voltage dividing resistor, a voltage stabilizing unit, a control switch and a controller; current temperature; the voltage dividing resistor and the thermistor are arranged in series to form a voltage dividing branch for a preset power supply, so as to realize the voltage dividing control of the voltage stabilizing unit and the control switch; The voltage stabilizing unit is configured to be in an off state when the current temperature reaches a preset over-temperature protection point of the switch tube, so as to control the conduction of the control switch in combination with the voltage dividing branch to Outputting a low-level signal to the controller of the motor, so that the controller controls the motor to stop according to the low-level signal.

Optionally, the voltage stabilizing unit is also configured to be in a conduction state when the current temperature has not reached the preset over-temperature protection point of the switch tube, so as to control the The control switch is turned off to output a high-level signal to the controller of the motor, so that the controller controls the motor to operate normally according to the high-level signal.

Optionally, the thermistor is set within a preset distance of the switching tube of the motor; and/or, the resistance value of the voltage dividing resistor can be based on the voltage value of the power supply, the thermal The resistance value of the sensitive resistor at the preset over-temperature protection point is determined.

Optionally, the voltage stabilizing unit includes: a three-terminal voltage regulator modeled as TL431; the reference terminal of the three-terminal voltage regulator is connected to the common end of the thermistor and the voltage dividing resistor, so The cathode of the three-terminal regulator is connected to the control terminal of the control switch.

Optionally, the thermistor includes: an NTC thermistor or a PTC thermistor; and/or the control switch includes: an NPN transistor or a PNP transistor.

Optionally, if the voltage stabilizing unit includes a three-terminal voltage regulator model TL431, the thermistor includes an NTC thermistor, and the control switch includes an NPN transistor, the base of the NPN transistor As the control terminal of the control switch, the emitter of the NPN transistor is connected to the signal input terminal of the controller as the output terminal of the control switch; If the thermistor includes a PTC thermistor, and the control switch includes a PNP transistor, the base of the PNP transistor is used as the control terminal of the control switch, and the collector of the PNP transistor is used as the control terminal. The output end of the switch is connected to the signal input end of the controller.

Optionally, it also includes: at least one of a first shunt resistor and a second shunt resistor; wherein, the first shunt resistor is arranged between the control terminal of the control switch and a preset power supply for use used to protect the voltage stabilizing unit and the control switch; and/or, the second shunt resistor is arranged between the output terminal of the control switch and a preset power supply, and is used to protect the voltage stabilizing unit. The pressure unit and the control switch are protected.

Matching the above device, another aspect of the present invention provides a motor, including: the above-mentioned over-temperature protection device for the motor.

Matching with the above-mentioned motor, another aspect of the present invention provides an over-temperature protection method for a motor, comprising: sensing the current temperature of the switch tube of the motor through a thermistor; Setting the formed voltage division branch to divide the preset power supply to realize the voltage division control of the voltage stabilizing unit and the control switch; through the voltage stabilizing unit, the preset temperature of the switch tube can be reached at the current temperature In the case of the over-temperature protection point, it is in an off state, so as to control the conduction of the control switch in combination with the voltage dividing branch to output a low-level signal, so as to control the motor to stop according to the low-level signal.

Optionally, it also includes: through a voltage stabilizing unit, when the current temperature does not reach the preset over-temperature protection point of the switch tube, it is in a conduction state, so as to control the voltage dividing branch in combination with the The control switch is turned off to output a high-level signal, so as to control the normal operation of the motor according to the high-level signal.

Optionally, it also includes: protecting the voltage stabilizing unit and the control switch through a first shunt resistor; and/or using a second shunt resistor to protect the voltage stabilizing unit and the control switch for protection.

In the solution of the present invention, by adding a protection circuit for detecting the temperature of the switch tube, it can effectively solve the failure of the DC motor caused by the burnout of the switch tube, and improve the protection reliability.

Furthermore, the solution of the present invention accurately detects the temperature of the switch tube to accurately perform protection shutdown, avoiding the failure of the motor caused by the burnout of the switch tube, and improving the reliability of protection and the safety of motor operation.

Further, the solution of the present invention, by effectively detecting the temperature of the switch tube, accurately protects the shutdown, avoids the failure of the motor caused by the burnout of the switch tube, can effectively reduce the after-sale defect rate of the motor, and improve the reliability and safety of the brushless DC motor .

Therefore, the solution of the present invention effectively detects the switch tube temperature by using an adjustable three-terminal voltage regulator, and then performs motor over-temperature protection, so that the brushless DC motor can be accurately shut down when the switch tube temperature reaches a certain value, solving the problem of existing In the technology, there is a problem of poor protection reliability for over-temperature shutdown protection by controlling the switch of the triode, so as to overcome the defects of poor protection reliability, high false protection rate and poor protection timeliness in the prior art, and realize good protection reliability and false protection. The beneficial effect of low rate and good protection timeliness.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is a schematic structural view of an embodiment of an overtemperature protection device for a motor of the present invention;

Fig. 2 is the electric schematic diagram of an embodiment of the over-temperature protection device of the motor of the present invention;

FIG. 3 is a schematic flowchart of an embodiment of the motor over-temperature protection method of the present invention.

In conjunction with the accompanying drawings, the reference signs in the embodiments of the present invention are as follows:

102-thermistor; 104-voltage divider resistor; 106-voltage stabilizing unit; 108-control switch; 110-controller.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

According to an embodiment of the present invention, an over-temperature protection device for a motor is provided, as shown in FIG. 1 , a schematic structural diagram of an embodiment of the device of the present invention. The over-temperature protection device of the motor may include: a thermistor 102 (such as NTC resistor, PTC resistor, etc.), a voltage dividing resistor 104 (such as a voltage dividing resistor 104R1 ), a voltage stabilizing unit 106 , a control switch 108 and a controller 110 .

In an optional example, the thermistor 102 can be used to sense the current temperature of the switching tube of the motor. For example: the thermistor NTC is affected by temperature, and its resistance changes to control the turn-on and turn-off of an adjustable three-terminal voltage regulator (such as TL431, a parallel voltage regulator integrated circuit), thereby controlling the turn-on and turn-off of the transistor Q1 off.

Wherein, the thermistor 102 is arranged within a preset distance of the switching tube of the motor (such as the switching tube used by the built-in controller 110 of the brushless DC motor).

For example: As shown in Figure 2, the temperature of the switch tube is detected by placing the NTC thermistor near the switch tube.

Therefore, by setting the thermistor within the preset distance of the switching tube of the built-in controller of the motor, it is beneficial to improve the accuracy and reliability of the current temperature sensing of the switching tube, thereby improving the protection and control of the motor over temperature reliability and safety.

Optionally, the thermistor 102 may include: an NTC thermistor 102 or a PTC thermistor 102 .

For example: for the practical application of the over-temperature protection circuit, the thermistor in the circuit can choose PTC, and the on-off and off conditions can be reset through the settings of the peripheral circuit to achieve the same function.

For example: NTC is a thermistor, which determines its own resistance by sensing temperature, and then controls the voltage drop input to TL431; NTC can be replaced by PTC; triode can be replaced by PNP type.

Therefore, through various forms of thermistors, it is beneficial to improve the accuracy of sensing the current temperature of the switching tube of the motor, and also improves the flexibility and convenience of the over-temperature protection of the motor.

In an optional example, the voltage dividing resistor 104 is arranged in series with the thermistor 102, which can be used to form a voltage dividing branch for a preset power supply, so as to realize the control of the voltage stabilizing unit 106 and the The voltage division control of the control switch 108 is described above. For example: the voltage dividing resistor 104 and the thermistor 102 are arranged in series between a preset power supply (such as a DC power supply VDD) and a ground signal (such as a GND signal).

Wherein, the resistance value of the voltage dividing resistor 104 can be determined according to the voltage value of the power supply and the resistance value of the thermistor at the preset over-temperature protection point.

For example: R1 is a voltage divider resistor, and the over-temperature protection point of the switch tube can be set by calculating its resistance value.

For example: in order to make the switch tube work in a reliable temperature range, it is necessary to set the temperature protection point in combination with the motor power and actual test during design. Set the NTC sensing temperature to 110°C for protection, and you can find the NTC resistance value R0 corresponding to the temperature of 110°C according to the NTC specification used; since the reference voltage of the adjustable three-terminal voltage regulator TL431 is 2.5V, in the switching power supply When the input voltage exceeds the upper limit voltage, it is in a conduction state, and the corresponding resistance value of R1 can be calculated:

For example: by selecting the appropriate R1 resistance value, the motor can be accurately and timely shut down at the set over-temperature protection point; according to the above calculation formula, assuming that VDD is 5V, select the NTC resistor with the model number 103KT1608T, and when the temperature is 110°C, The resistance of NTC is 770Ω, and the resistance of R1 can be calculated as 770Ω. By using this circuit, the motor over-temperature protection function can be realized accurately and timely, thereby ensuring the reliability and safety of the motor.

Therefore, by determining the resistance value of the voltage dividing resistor, the motor can be reliably stopped at the preset over-temperature protection point of the motor, which is conducive to improving the accuracy and timeliness of the motor's over-temperature protection, thereby improving the over-temperature protection of the motor. reliability and safety.

Optionally, the voltage stabilizing unit 106 may include: a three-terminal voltage regulator whose model is TL431.

Wherein, the reference terminal of the three-terminal voltage regulator is connected to the common terminal of the thermistor 102 and the voltage dividing resistor 104, and the cathode of the three-terminal voltage regulator is connected to the control terminal of the control switch 108 , the anode of the three-terminal regulator is grounded.

For example: TL431 has a precise turn-on voltage, so using an adjustable three-terminal voltage regulator (such as TL431) for motor over-temperature protection can realize accurate shutdown of the brushless DC motor when the temperature of the switch tube reaches a certain value.

For example: use TL431 with high switching precision to realize high-precision over-temperature protection. TL431 is an adjustable three-terminal voltage regulator with high switching precision and only one switching point, and its switch can control the switching of the triode.

Therefore, by selecting TL431 as the voltage stabilizing unit, the reliability and accuracy of the voltage stabilizing control can be guaranteed, thereby improving the reliability of the motor over-temperature protection.

In an optional example, the voltage stabilizing unit 106 can be configured to be in an off state when the current temperature reaches the preset over-temperature protection point of the switch tube, so as to combine the voltage dividing branch The circuit controls the control switch 108 to be turned on and output a low-level signal to the controller 110 of the motor (such as the built-in controller 110 of the brushless DC motor), so that the controller 110 can The signal controls the motor to stop. For example: as shown in Figure 2, when the temperature of the switch tube (such as the transistor Q1) exceeds the safe range, the resistance of the NTC decreases, TL431 is turned off, Q1 is turned on, and FO (such as the emitter of the transistor Q1) outputs a low level to the MCU , MCU sends a control signal to stop the motor. When the temperature of the switch tube (such as switch tube Q1) reaches the over-temperature protection point (such as the set safety range) during the working process, the resistance value of the NTC resistor decreases, and the voltage drop of the resistor divider decreases, resulting in an adjustable three-terminal regulator. The input voltage of the voltage regulator is less than 2.5V. At this time, the TL431 is in the off state, the transistor Q1 is turned on, the FO outputs a low level to the MUC, and the MCU sends a control signal to stop the motor.

For example: in the process of specific implementation, when the current temperature reaches the preset over-temperature protection point of the switch tube, a reminder message for the overtemperature of the switch tube can be initiated, such as a voice reminder message, a buzzer Initiate reminder messages by means of device alarm reminder, display screen display, etc.

For example, adding a protection circuit for switching tube temperature detection can effectively detect the temperature of the switching tube and accurately protect the shutdown, avoiding the failure of the motor caused by the burning of the switching tube, thereby effectively solving the failure of the DC motor caused by the burning of the switching tube. For example: it can effectively detect the temperature of the switch tube to accurately protect the shutdown, avoid the failure of the motor caused by the burnout of the switch tube, effectively reduce the after-sale defect rate of the motor, and improve the reliability and safety of the brushless DC motor.

Therefore, the current temperature of the switching tube of the built-in controller of the motor is sensed by the thermistor, and then the voltage stabilizing unit is turned off, and the control switch is turned on by combining the voltage dividing branch formed by the thermistor and the voltage dividing resistor in series. And output low-level signal to the built-in controller of the motor, so that the built-in controller stops the motor according to the low-level signal, so as to reliably realize the over-temperature protection of the motor, and the timeliness and accuracy of the protection are guaranteed. ensure.

Optionally, the control switch 108 may include: an NPN transistor or a PNP transistor.

For example: for the practical application of the over-temperature protection circuit, Q1 in the circuit can use a PNP transistor, and reset the on and off conditions through the settings of the peripheral circuit to achieve the same function.

For example: Q1 is a triode, which triggers the MCU to perform shutdown protection by controlling its switch.

Therefore, through various forms of control switches, it is beneficial to improve the accuracy of sending control signals to the built-in controller combined with the voltage stabilization unit, and also improves the flexibility and convenience of motor over-temperature protection.

More optionally, if the voltage stabilizing unit 106 can include a three-terminal voltage regulator model TL431, the thermistor 102 can include an NTC thermistor 102, and the control switch 108 can include an NPN transistor, then the The base of the NPN transistor is used as the control terminal of the control switch 108 , and the emitter of the NPN transistor is used as the output terminal of the control switch 108 , which is connected to the signal input terminal of the controller 110 . The collector of the NPN transistor is grounded.

If the voltage stabilizing unit 106 can include a three-terminal voltage regulator whose model is TL431, the thermistor 102 can include a PTC thermistor 102, and the control switch 108 can include a PNP triode, then the PNP triode The base serves as the control terminal of the control switch 108 , and the collector of the PNP transistor serves as the output terminal of the control switch 108 and is connected to the signal input terminal of the controller 110 . The emitter of the NPN triode is grounded.

Therefore, by adapting and setting the control relationship according to the different forms of the voltage stabilizing unit, control switch and thermistor, it is beneficial to improve the reliability and flexibility of the control of the motor over-temperature protection, and also improve the operation of the motor over-temperature protection. convenience.

In an optional example, the voltage stabilizing unit 106 can also be configured to be in an on state when the current temperature has not reached the preset over-temperature protection point of the switch tube, so as to combine the dividing The voltage branch controls the control switch 108 to turn off and outputs a high-level signal to the controller 110 of the motor, so that the controller 110 can control the motor to operate normally according to the high-level signal. For example: as shown in Figure 2, when the temperature of the switch tube does not exceed the safe range, the resistance of the NTC increases, TL431 is turned on, Q1 is turned off, FO outputs a high level to the MCU, and the motor runs normally. When the temperature of the switch tube (such as switch tube Q1) does not reach the over-temperature protection point during the working process, the resistance value of the NTC resistor increases, the voltage drop of the resistor divider increases, and the voltage input to the adjustable three-terminal voltage regulator is greater than 2.5 V, at this time TL431 is in the conduction state, the transistor Q1 is cut off, FO outputs a high level to MUC, and MCU sends a control signal to make the motor run normally.

Therefore, when the current temperature of the switching tube of the motor has not reached the over-temperature protection point, the voltage stabilizing unit is turned on, and the voltage-dividing branch formed in series with the thermistor and the voltage-dividing resistor makes the control switch Turn off and output a high-level signal to the built-in controller of the motor, so that the built-in controller can make the motor run normally according to the high-level signal, thereby avoiding the false protection of the motor, reducing the false protection rate, and improving the motor. Reliability of operation and reliability of over-temperature protection.

In an optional example, it may further include: at least one of a first shunt resistor (such as a shunt resistor R2 ) and a second shunt resistor (such as a shunt resistor R3 ).

For example: In Figure 2, R2 and R3 are current limiting resistors.

In an optional example, the first shunt resistor is set between the control terminal of the control switch 108 and a preset power supply, and can be used to control the voltage stabilizing unit 106 and the control switch 108 protection (for example: performing shunt control on the control terminal of the control switch 108).

In an optional example, the second shunt resistor is arranged between the output terminal of the control switch 108 and a preset power supply, and can be used to perform Protection (for example: performing shunt control on the output terminal of the control switch 108).

For example: as shown in Figure 2, the current limiting resistors R2, R3, etc., can prevent Q1 and TL431 from being damaged due to excessive current when they are turned on.

Therefore, through the adaptive setting of the shunt resistor, it is beneficial to improve the safety of the over-temperature protection control of the motor, and thus can better ensure the reliability and accuracy of the over-temperature protection control of the motor.

After a large number of tests and verifications, the technical solution of this embodiment can effectively solve the failure of the DC motor caused by the burnout of the switch tube by adding a protection circuit for temperature detection of the switch tube, and improve the protection reliability.

According to an embodiment of the present invention, a motor corresponding to an over-temperature protection device for the motor is also provided. The motor may include: the above-mentioned over-temperature protection device for the motor.

In an optional implementation, considering that the switch tube used in the built-in controller of the brushless DC motor will heat up severely during the high-speed turn-on and turn-off process, if the operating temperature range of the switch tube is exceeded, the switch tube will burn out . The solution of the present invention adds a temperature detection and protection circuit for the switch tube, which can effectively solve the failure of the DC motor caused by the burnout of the switch tube.

In an optional example, the present invention proposes a high-precision over-temperature protection circuit, which can effectively detect the temperature of the switch tube and accurately perform protection shutdown, so as to avoid motor failure caused by the burnout of the switch tube. That is to say, a high-precision over-temperature protection circuit proposed by the present invention can effectively detect the temperature of the switch tube and accurately protect and shut down the motor, avoiding the failure of the motor caused by the burnout of the switch tube, effectively reducing the after-sale defect rate of the motor, and improving The reliability and safety of brushless DC motors.

In an optional specific example, the solution of the present invention, as shown in Figure 2, detects the temperature of the switch tube by placing the NTC thermistor near the switch tube, and the thermistor NTC is affected by the temperature, and its resistance changes to Control the turn-on and turn-off of an adjustable three-terminal voltage regulator (such as TL431, a parallel voltage regulator integrated circuit), and then control the turn-on and turn-off of the transistor Q1. When the temperature of the switch tube (such as the transistor Q1) exceeds the safe range, the NTC resistance decreases, TL431 is turned off, Q1 is turned on, FO (such as the emitter of the transistor Q1) outputs a low level to the MCU, and the MCU sends a control signal to stop the motor ;When the temperature of the switch tube does not exceed the safe range, the NTC resistance increases, TL431 is turned on, Q1 is turned off, FO outputs a high level to the MCU, and the motor runs normally; the traditional over-temperature protection circuit uses the turn-on and turn-off of the triode to control the FO level The level realizes the over-temperature protection of the motor. Since the conduction voltage of the general triode Vbe is 0.7V to 1.0V, and the conduction voltage range is relatively large, it may cause the motor to be incorrectly protected or not protected in time. TL431 has a precise turn-on voltage, so using an adjustable three-terminal voltage regulator (such as TL431) for motor over-temperature protection can realize precise shutdown of the brushless DC motor when the temperature of the switch tube reaches a certain value.

Among them, in Figure 2, Q1 is a triode, by controlling the on and off of the triode Q1, the high and low level of FO output is controlled, TL431 is an adjustable three-terminal voltage regulator, NTC is a thermistor, R1 is a voltage divider resistor, The over-temperature protection point of the switch tube can be set by calculating its resistance value; R2 and R3 are current-limiting resistors.

Specifically, the specific working principle of the present invention is described as follows:

When the temperature of the switch tube (such as switch tube Q1) reaches the over-temperature protection point (such as the set safety range) during the working process, the resistance value of the NTC resistor decreases, and the voltage drop of the resistor divider decreases, resulting in an adjustable three-terminal regulator. The input voltage of the voltage regulator is less than 2.5V. At this time, the TL431 is in the off state, the transistor Q1 is turned on, the FO outputs a low level to the MUC, and the MCU sends a control signal to stop the motor.

When the temperature of the switch tube (such as switch tube Q1) does not reach the over-temperature protection point during the working process, the resistance value of the NTC resistor increases, the voltage drop of the resistor divider increases, and the voltage input to the adjustable three-terminal voltage regulator is greater than 2.5 V, at this time TL431 is in the conduction state, the transistor Q1 is cut off, FO outputs a high level to MUC, and MCU sends a control signal to make the motor run normally.

The temperature range of the switch tube currently used is generally -55°C--150°C. In order to make the switch tube work in a reliable temperature range, it is necessary to set the temperature protection point in combination with the motor power and actual test during design.

For example, if the NTC sensing temperature is set to 110°C for protection, the NTC resistance value R0 corresponding to the temperature of 110°C can be found according to the NTC specification used; since the reference voltage of the adjustable three-terminal regulator TL431 is 2.5V, the switch When the input voltage of the power supply exceeds the upper limit voltage, it is in a conduction state, and the corresponding resistance value of R1 can be calculated:

The advantage of this circuit is that by selecting the appropriate resistance value of R1, the motor can be accurately and timely shut down at the set over-temperature protection point; according to the above calculation formula, assuming that VDD is 5V, select the NTC resistor of model 103KT1608T, and the temperature is At 110°C, the resistance of NTC is 770Ω, and the resistance of R1 can be calculated as 770Ω.

By using this circuit, the motor over-temperature protection function can be realized accurately and timely, thereby ensuring the reliability and safety of the motor.

In an alternative example, it can be aimed at the actual application of the over-temperature protection circuit. In the circuit, Q1 can use a PNP transistor, and the thermistor can choose PTC, and the on-off and off conditions can be reset through the settings of the peripheral circuit. , to achieve the same function.

Since the processing and functions realized by the motor of this embodiment basically correspond to the embodiment, principle and example of the device shown in Figure 1 to Figure 2, the description of this embodiment is not detailed, you can refer to the previous embodiment Relevant descriptions in , will not be repeated here.

After a large number of tests and verifications, the technical solution of the present invention can accurately detect the temperature of the switch tube to accurately protect the shutdown, avoid the burnout of the switch tube and cause the motor to fail, and improve the reliability of the protection and the safety of the motor operation.

According to an embodiment of the present invention, a motor over-temperature protection method corresponding to the motor over-temperature protection device is also provided. Refer to the schematic flowchart of an embodiment of the method of the present invention shown in FIG. 3 . The over-temperature protection method of the motor may include: step S110 to step S130.

At step S110, the thermistor 102 can be used to sense the current temperature of the switching tube of the motor. The thermistor 102 is arranged within a preset distance of the switching tube of the motor (such as the switching tube used by the built-in controller 110 of the brushless DC motor).

At step S120 , the preset power supply is divided by the voltage dividing branch formed by the voltage dividing resistor 104 and the thermistor 102 arranged in series, so as to realize the voltage dividing control of the voltage stabilizing unit 106 and the control switch 108 . For example: the voltage dividing resistor 104 and the thermistor 102 are arranged in series between a preset power supply (such as a DC power supply VDD) and a ground signal (such as a GND signal).

At step S130, through the voltage stabilizing unit 106, when the current temperature reaches the preset over-temperature protection point of the switching tube, it is turned off, so as to control the control switch in combination with the voltage dividing branch 108 is turned on to output a low-level signal, so as to control the motor to stop according to the low-level signal. For example: as shown in Figure 2, when the temperature of the switch tube (such as the transistor Q1) exceeds the safe range, the resistance of the NTC decreases, TL431 is turned off, Q1 is turned on, and FO (such as the emitter of the transistor Q1) outputs a low level to the MCU , MCU sends a control signal to stop the motor. When the temperature of the switch tube (such as switch tube Q1) reaches the over-temperature protection point (such as the set safety range) during the working process, the resistance value of the NTC resistor decreases, and the voltage drop of the resistor divider decreases, resulting in an adjustable three-terminal regulator. The input voltage of the voltage regulator is less than 2.5V. At this time, the TL431 is in the off state, the transistor Q1 is turned on, the FO outputs a low level to the MUC, and the MCU sends a control signal to stop the motor.

For example: in the process of specific implementation, when the current temperature reaches the preset over-temperature protection point of the switch tube, a reminder message for the overtemperature of the switch tube can be initiated, such as a voice reminder message, a buzzer Initiate reminder messages by means of device alarm reminder, display screen display, etc.

For example, adding a protection circuit for switching tube temperature detection can effectively detect the temperature of the switching tube and accurately protect the shutdown, avoiding the failure of the motor caused by the burning of the switching tube, thereby effectively solving the failure of the DC motor caused by the burning of the switching tube. For example: it can effectively detect the temperature of the switch tube to accurately protect the shutdown, avoid the failure of the motor caused by the burnout of the switch tube, effectively reduce the after-sale defect rate of the motor, and improve the reliability and safety of the brushless DC motor.

Therefore, the current temperature of the switching tube of the built-in controller of the motor is sensed by the thermistor, and then the voltage stabilizing unit is turned off, and the control switch is turned on by combining the voltage dividing branch formed by the thermistor and the voltage dividing resistor in series. And output low-level signal to the built-in controller of the motor, so that the built-in controller stops the motor according to the low-level signal, so as to reliably realize the over-temperature protection of the motor, and the timeliness and accuracy of the protection are guaranteed. ensure.

In an optional implementation manner, it may also include: through the voltage stabilizing unit 106, when the current temperature has not reached the preset over-temperature protection point of the switch tube, it is turned on, so as to combine the divided The voltage branch controls the control switch 108 to be turned off to output a high-level signal, so as to control the normal operation of the motor according to the high-level signal. For example: as shown in Figure 2, when the temperature of the switch tube does not exceed the safe range, the resistance of the NTC increases, TL431 is turned on, Q1 is turned off, FO outputs a high level to the MCU, and the motor runs normally. When the temperature of the switch tube (such as switch tube Q1) does not reach the over-temperature protection point during the working process, the resistance value of the NTC resistor increases, the voltage drop of the resistor divider increases, and the voltage input to the adjustable three-terminal voltage regulator is greater than 2.5 V, at this time TL431 is in the conduction state, the transistor Q1 is cut off, FO outputs a high level to MUC, and MCU sends a control signal to make the motor run normally.

Therefore, when the current temperature of the switching tube of the motor has not reached the over-temperature protection point, the voltage stabilizing unit is turned on, and the voltage-dividing branch formed in series with the thermistor and the voltage-dividing resistor makes the control switch Turn off and output a high-level signal to the built-in controller of the motor, so that the built-in controller can make the motor run normally according to the high-level signal, thereby avoiding the false protection of the motor, reducing the false protection rate, and improving the motor. Reliability of operation and reliability of over-temperature protection.

In an optional implementation manner, it may also include: protecting the voltage stabilizing unit 106 and the control switch 108 through a first shunt resistor (for example: performing shunt control on the control terminal of the control switch 108); And/or, the second shunt resistor can be used to protect the voltage stabilizing unit 106 and the control switch 108 (for example: perform shunt control on the output terminal of the control switch 108 ).

For example: in Figure 2, R2 and R3 are current-limiting resistors, which can prevent Q1 and TL431 from being damaged due to excessive current when they are turned on.

Therefore, through the adaptive setting of the shunt resistor, it is beneficial to improve the safety of the over-temperature protection control of the motor, and thus can better ensure the reliability and accuracy of the over-temperature protection control of the motor.

Since the processing and functions realized by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned motors, for the details not described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, which are not mentioned here. Do repeat.

After a large number of tests and verifications, the technical scheme of the present invention can be used to accurately detect the temperature of the switch tube to accurately protect the shutdown, avoid the burnout of the switch tube and cause the motor to fail, can effectively reduce the after-sale defect rate of the motor, and improve the efficiency of the brushless DC motor. reliability and safety.

To sum up, those skilled in the art can easily understand that, on the premise of no conflict, the above-mentioned advantageous ways can be freely combined and superimposed.

The above description is only an embodiment of the present invention, and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of the claims of the present invention.

Claims (11)

1. An over-temperature protection device for a motor, comprising: a thermistor (102), a voltage dividing resistor (104), a voltage stabilizing unit (106) and a control switch (108); wherein, The thermistor (102) is used to sense the current temperature of the switching tube of the motor; The voltage dividing resistor (104) is arranged in series with the thermistor (102), and is used to form a voltage dividing branch for a preset power supply, so as to realize the control of the voltage stabilizing unit (106) and the Voltage division control of switch (108); The voltage stabilizing unit (106), configured to be in an off state when the current temperature reaches a preset over-temperature protection point of the switch tube, so as to control the control switch in combination with the voltage dividing branch (108) is turned on to output a low-level signal to the controller (110) of the motor, so that the controller (110) controls the motor to stop according to the low-level signal. 2. The device according to claim 1, characterized in that the voltage stabilizing unit (106) is further configured to, when the current temperature has not reached the preset over-temperature protection point of the switching tube, display conduction state, to control the control switch (108) to turn off in combination with the voltage dividing branch to output a high level signal to the controller (110), so that the controller (110) The level signal controls the normal operation of the motor. 3. The device according to claim 1 or 2, wherein, The thermistor (102) is arranged within a preset distance of the switching tube of the motor; and / or, The resistance value of the voltage dividing resistor (104) can be determined according to the voltage value of the power supply and the resistance value of the thermistor at the preset over-temperature protection point. 4. The device according to any one of claims 1-3, characterized in that, the voltage stabilizing unit (106) comprises: a three-terminal voltage regulator whose model is TL431; The reference terminal of the three-terminal voltage regulator is connected to the common end of the thermistor (102) and the voltage dividing resistor (104), and the cathode of the three-terminal voltage regulator is connected to the control switch (108 ) control terminal. 5. The device according to any one of claims 1-4, wherein, The thermistor (102) includes: NTC thermistor (102) or PTC thermistor (102); and/or, The control switch (108) includes: an NPN transistor or a PNP transistor. 6. The device according to claim 5, wherein, If the voltage stabilizing unit (106) includes a three-terminal voltage regulator model TL431, the thermistor (102) includes an NTC thermistor (102), and the control switch (108) includes an NPN transistor, then the The base of the NPN transistor is used as the control terminal of the control switch (108), and the emitter of the NPN transistor is used as the output terminal of the control switch (108), which is connected to the signal input terminal of the controller (110). ; If the voltage stabilizing unit (106) includes a three-terminal voltage regulator model TL431, the thermistor (102) includes a PTC thermistor (102), and the control switch (108) includes a PNP transistor, then the The base of the PNP transistor is used as the control terminal of the control switch (108), and the collector of the PNP transistor is connected to the signal input terminal of the controller (110) as the output terminal of the control switch (108). . 7. The device according to any one of claims 1-6, further comprising: at least one of the first shunt resistor and the second shunt resistor; wherein, The first shunt resistor is arranged between the control terminal of the control switch (108) and a preset power supply, and is used to protect the voltage stabilizing unit (106) and the control switch (108); and / or, The second shunt resistor is arranged between the output terminal of the control switch (108) and a preset power supply, and is used to protect the voltage stabilizing unit (106) and the control switch (108). 8. A motor, characterized by comprising: the over-temperature protection device for a motor according to any one of claims 1-7. 9. An over-temperature protection method for a motor as claimed in claim 8, characterized in that it comprises: A thermistor (102) is used to sense the current temperature of the switching tube of the motor; Through the voltage dividing branch formed by the voltage dividing resistor (104) and the thermistor (102) arranged in series, the preset power supply is divided to realize the division of the voltage stabilizing unit (106) and the control switch (108). pressure control; Through the voltage stabilizing unit (106), when the current temperature reaches the preset over-temperature protection point of the switch tube, it is turned off, so as to control the control switch (108) in combination with the voltage dividing branch. is turned on to output a low-level signal, so as to control the motor to stop according to the low-level signal. 10. The method of claim 9, further comprising: Through the voltage stabilizing unit (106), when the current temperature has not reached the preset over-temperature protection point of the switch tube, it is in a conduction state, so as to control the control switch (108) in combination with the voltage dividing branch ) is turned off to output a high-level signal, so as to control the normal operation of the motor according to the high-level signal. 11. The method according to claim 9 or 10, further comprising: Protecting the voltage stabilizing unit (106) and the control switch (108) through a first shunt resistor; and/or, The second shunt resistor is used to protect the voltage stabilizing unit (106) and the control switch (108).