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

Abstract

The present invention discloses an over-temperature protection device for a motor, a motor and an over-temperature protection method thereof, the device comprising: a thermistor for sensing the current temperature of the switch tube of the motor; a 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 voltage-dividing control of the voltage-stabilizing unit and the control switch; the voltage-stabilizing unit is used to be in a shut-off state when the current temperature reaches the preset over-temperature protection point of the switch tube, so as to control the control switch to conduct 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 scheme of the present invention can solve the problem of poor protection reliability in the prior art of over-temperature shutdown protection by controlling the switch of the triode, and achieve the effect of improving protection reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of temperature protection, and specifically relates to an over-temperature protection device of a motor, a motor and an over-temperature protection method thereof, and more particularly to a high-precision over-temperature protection circuit, a motor having the over-temperature protection circuit, and an over-temperature protection method of the motor. Background Art

[0002] Due to the characteristics of high efficiency, large starting torque and convenient control, the application field of brushless DC motor is becoming more and more extensive. Brushless DC motor is mainly composed of two parts: motor body and controller. The controller part includes control chip, power drive circuit, position detection circuit, signal feedback circuit and other circuits; the power drive circuit is generally composed of signal amplification circuit and full-bridge (or half-bridge) inverter circuit. The switch tube in the inverter circuit will generate serious heat during high-speed opening or closing. 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.

[0003] Therefore, in order to avoid failure of the brushless DC motor due to overheating of the switch tube device, it is necessary to add an over-temperature protection circuit when designing the brushless DC motor controller. Therefore, a high-precision over-temperature protection circuit is designed for the switch tube in the brushless DC motor controller. The existing over-temperature protection circuit controls the switch of the transistor to perform over-temperature shutdown protection. Since the control voltage range of the transistor switch is large, generally 0.7V to 1.0V, it can cause the motor to be misprotected or untimely protected. Summary of the invention

[0004] The purpose of the present invention is to provide an over-temperature protection device for a motor, a motor and an over-temperature protection method for a motor in view of the above-mentioned defects, so as to solve the problem of poor protection reliability in the prior art of over-temperature shutdown protection by controlling the switch of the transistor, thereby achieving the effect of improving the protection reliability.

[0005] 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; wherein the thermistor is used to sense the current temperature of a switch tube of the motor; the voltage-dividing resistor is arranged in series with the thermistor to form a voltage-dividing branch for a preset power supply, so as to realize voltage-dividing control of the voltage-stabilizing unit and the control switch; the voltage-stabilizing unit is used to be in a shut-off state when the current temperature reaches a preset over-temperature protection point of the switch tube, so as to control the control switch to be turned on 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.

[0006] Optionally, the voltage stabilizing unit is also used to be in an on state when the current temperature has not reached the preset over-temperature protection point of the switching tube, so as to combine with the voltage divider branch to control the control switch to turn off and output a high-level signal to the controller of the motor, so that the controller controls the normal operation of the motor according to the high-level signal.

[0007] Optionally, the thermistor is arranged within a preset distance of the switch tube of the motor; and / or the resistance of the voltage divider resistor can be determined according to the voltage value of the power supply and the resistance of the thermistor at the preset over-temperature protection point.

[0008] Optionally, the voltage stabilizing unit includes: a three-terminal voltage regulator of model TL431; the reference end of the three-terminal voltage regulator is connected to the common end of the thermistor and the voltage divider resistor, and the cathode of the three-terminal voltage regulator is connected to the control end of the control switch.

[0009] Optionally, the thermistor includes: an NTC thermistor or a PTC thermistor; and / or the control switch includes: an NPN transistor or a PNP transistor.

[0010] Optionally, if the voltage stabilizing unit includes a three-terminal voltage regulator with a model number of TL431, the thermistor includes an NTC thermistor, and the control switch includes an NPN transistor, then the base of the NPN transistor serves as the control end of the control switch, and the emitter of the NPN transistor serves as the output end of the control switch, connected to the signal input end of the controller; if the voltage stabilizing unit includes a three-terminal voltage regulator with a model number of TL431, the thermistor includes a PTC thermistor, and the control switch includes a PNP transistor, then the base of the PNP transistor serves as the control end of the control switch, and the collector of the PNP transistor serves as the output end of the control switch, connected to the signal input end of the controller.

[0011] 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 end of the control switch and a preset power supply, and is used to protect the voltage stabilizing unit and the control switch; and / or the second shunt resistor is arranged between the output end of the control switch and a preset power supply, and is used to protect the voltage stabilizing unit and the control switch.

[0012] Matching the above device, the present invention further provides a motor on the other hand, including: the above-mentioned over-temperature protection device for the motor.

[0013] Matching the above-mentioned motor, the present invention provides a motor over-temperature protection method on the other hand, including: using a thermistor to sense the current temperature of the switch tube of the motor; using a voltage-dividing resistor and a thermistor in series to form a voltage-dividing branch to divide the preset power supply, so as to achieve voltage-dividing control of a voltage stabilizing unit and a control switch; using the voltage stabilizing unit, when the current temperature reaches the preset over-temperature protection point of the switch tube, the voltage stabilizing unit is in a shut-off state, so as to control the control switch to be turned on in combination with the voltage-dividing branch and output a low-level signal, so as to control the motor to stop according to the low-level signal.

[0014] Optionally, it also includes: through a voltage stabilizing unit, when the current temperature does not reach the preset over-temperature protection point of the switching tube, it is in an on state, so as to control the control switch to be turned off in combination with the voltage divider branch and output a high-level signal, so as to control the normal operation of the motor according to the high-level signal.

[0015] Optionally, it also includes: protecting the voltage stabilizing unit and the control switch through a first shunt resistor; and / or protecting the voltage stabilizing unit and the control switch through a second shunt resistor.

[0016] The solution of the present invention can effectively solve the failure of the DC motor caused by the burning of the switching tube by adding a protection circuit for detecting the temperature of the switching tube, thereby improving the protection reliability.

[0017] Furthermore, the solution of the present invention effectively detects the temperature of the switch tube and accurately performs a protective shutdown, thereby avoiding motor failure caused by burning of the switch tube, thereby improving the reliability of protection and the safety of motor operation.

[0018] Furthermore, the solution of the present invention can effectively detect the temperature of the switch tube and accurately perform a protective shutdown to avoid motor failure caused by burning of the switch tube, thereby effectively reducing the after-sales defective rate of the motor and improving the reliability and safety of the brushless DC motor.

[0019] Therefore, the scheme of the present invention, by using an adjustable three-terminal regulator to effectively detect the temperature of the switch tube, and then perform over-temperature protection for the motor, can realize the accurate shutdown of the brushless DC motor when the temperature of the switch tube reaches a certain value, thereby solving the problem of poor protection reliability in the prior art of over-temperature shutdown protection by controlling the switch of the transistor. Thus, the defects of poor protection reliability, high false protection rate and poor protection timeliness in the prior art are overcome, and the beneficial effects of good protection reliability, low false protection rate and good protection timeliness are achieved.

[0020] Other features and advantages of the present 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 present invention.

[0021] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of an embodiment of an over-temperature protection device for a motor of the present invention;

[0023] Figure 2 It is a schematic diagram of the electrical principle of an embodiment of an over-temperature protection device for a motor of the present invention;

[0024] Figure 3 FIG. 4 is a flow chart of an embodiment of a method for over-temperature protection of a motor according to the present invention.

[0025] In conjunction with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0026] 102 - thermistor; 104 - voltage-dividing resistor; 106 - voltage-stabilizing unit; 108 - control switch; 110 - controller. DETAILED DESCRIPTION

[0027] 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 the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] According to an embodiment of the present invention, there is provided an over-temperature protection device for a motor, such as Figure 1 The over-temperature protection device of the motor may include: a thermistor 102 (such as an NTC resistor, a PTC resistor, etc.), a voltage divider resistor 104 (such as a voltage divider resistor 104R1), a voltage stabilizing unit 106, a control switch 108 and a controller 110.

[0029] In an optional example, the thermistor 102 can be used to sense the current temperature of the switch tube of the motor. For example, the thermistor NTC is affected by temperature, and its resistance changes to control the opening and closing of an adjustable three-terminal regulator (such as TL431, a shunt regulator integrated circuit), thereby controlling the conduction and closing of the transistor Q1.

[0030] The thermistor 102 is arranged within a preset distance from a switch tube of the motor (such as a switch tube used by a built-in controller 110 of a brushless DC motor).

[0031] For example: Figure 2As shown, the temperature of the switch tube is detected by placing an NTC thermistor near the switch tube.

[0032] Therefore, by setting the thermistor within a preset distance of the switch tube of the built-in controller of the motor, it is helpful to improve the accuracy and reliability of the current temperature sensing of the switch tube, thereby improving the reliability and safety of the motor over-temperature protection control.

[0033] Optionally, the thermistor 102 may include: an NTC thermistor 102 or a PTC thermistor 102 .

[0034] For example, for the actual application of over-temperature protection circuit, the thermistor in the circuit can be selected as PTC, and the on and off conditions can be reset by setting the peripheral circuit to achieve the same function.

[0035] For example: NTC is a thermistor, which determines its own resistance by sensing temperature, thereby controlling the voltage drop input to TL431; NTC can be replaced by PTC; transistor can be replaced by PNP type.

[0036] Therefore, various forms of thermistors can help improve the accuracy of sensing the current temperature of the motor's switch tube, and also improve the flexibility and convenience of motor over-temperature protection.

[0037] In an optional example, the voltage-dividing resistor 104 and the thermistor 102 are arranged in series, and can be used to form a voltage-dividing branch for a preset power supply, so as to realize 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).

[0038] 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.

[0039] For example: R1 is a voltage-dividing resistor, and the over-temperature protection point of the switch tube can be set by calculating its resistance value.

[0040] For example: In order to make the switch tube work in a reliable temperature range, the temperature protection point needs to be set in combination with the motor power and actual test during design. Set the NTC sensing temperature to 110℃ for protection. You can find the NTC resistance value R0 corresponding to the temperature of 110℃ according to the NTC specification sheet used; since the reference voltage of the adjustable three-terminal regulator TL431 is 2.5V, it is in the on state when the input voltage of the switching power supply exceeds the upper limit voltage, and the corresponding resistance value of R1 can be calculated:

[0041]

[0042]

[0043] For example: by selecting the appropriate R1 resistance value, the motor can be shut down accurately and timely at the set over-temperature protection point; according to the above calculation formula, assuming that VDD is 5V, the NTC resistor model is 103KT1608T, and the temperature is 110℃, the NTC resistance is 770Ω, and the R1 resistance can be calculated to be 770Ω. Using this circuit, the motor over-temperature protection function can be realized accurately and timely, thereby ensuring the reliability and safety of the motor.

[0044] Therefore, by determining the resistance value of the voltage divider resistor, the motor can be reliably shut down at the preset over-temperature protection point of the motor, which is beneficial to improving the accuracy and timeliness of the motor over-temperature protection, and then improving the reliability and safety of the motor over-temperature protection.

[0045] Optionally, the voltage stabilizing unit 106 may include: a three-terminal voltage regulator of model TL431.

[0046] The reference terminal of the three-terminal regulator is connected to the common terminal of the thermistor 102 and the voltage divider resistor 104 , the cathode of the three-terminal regulator is connected to the control terminal of the control switch 108 , and the anode of the three-terminal regulator is grounded.

[0047] For example, TL431 has a precise on-state voltage, so using an adjustable three-terminal regulator (such as TL431) for motor over-temperature protection can achieve precise shutdown of the brushless DC motor when the switch tube temperature reaches a certain value.

[0048] For example, use TL431 with high switching accuracy to achieve high-precision over-temperature protection. TL431 is an adjustable three-terminal regulator with high switching accuracy and only one switching point. Its switch can control the switching of the transistor.

[0049] Therefore, by selecting TL431 as the voltage stabilization unit, the reliability and accuracy of the voltage stabilization control can be guaranteed, thereby improving the reliability of the motor over-temperature protection.

[0050] In an optional example, the voltage stabilizing unit 106 can be used to be in a shut-down state when the current temperature reaches the preset over-temperature protection point of the switch tube, so as to combine with the voltage dividing branch to control 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 control the motor to stop according to the low-level signal. Figure 2As shown in the figure, when the temperature of the switch tube (such as transistor Q1) exceeds the safe range, the resistance of the NTC decreases, the TL431 is turned off, Q1 is turned on, and the 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 (such as the switch tube Q1) reaches the over-temperature protection point (such as the set safe range) during operation, the resistance of the NTC resistor decreases, and the voltage drop of the resistor divider decreases, causing the input voltage of the adjustable three-terminal regulator to be less than 2.5V. At this time, the TL431 is turned off, 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.

[0051] For example: During the specific implementation process, when the current temperature reaches the preset over-temperature protection point of the switch tube, a reminder message of over-temperature of the switch tube can be initiated, such as by voice reminder message, buzzer alarm reminder, display screen display, etc.

[0052] For example: adding a temperature detection protection circuit for the switch tube can effectively detect the temperature of the switch tube and accurately shut down the machine for protection, avoiding motor failure caused by the switch tube burning out, thereby effectively solving the DC motor failure caused by the switch tube burning out. For example: the temperature of the switch tube can be effectively detected and accurately shut down the machine for protection, avoiding motor failure caused by the switch tube burning out, which can effectively reduce the after-sales defective rate of the motor and improve the reliability and safety of the brushless DC motor.

[0053] Therefore, the current temperature of the switch tube of the built-in controller of the motor is sensed by the thermistor, so that the voltage stabilizing unit is in the off state, and the voltage dividing branch formed by the thermistor and the voltage dividing resistor in series is combined to turn on the control switch and output a low-level signal to the built-in controller of the motor, so that the built-in controller shuts down the motor according to the low-level signal, thereby reliably realizing over-temperature protection of the motor, and the timeliness and accuracy of the protection are guaranteed.

[0054] Optionally, the control switch 108 may include: an NPN transistor or a PNP transistor.

[0055] For example, for the actual application of over-temperature protection circuit, Q1 in the circuit can use a PNP transistor, and the on and off conditions can be reset by setting the peripheral circuit to achieve the same function.

[0056] For example: Q1 is a transistor, and its switch is controlled to trigger the MCU to perform shutdown protection.

[0057] Therefore, through various forms of control switches, it is helpful to improve the accuracy of sending control signals to the built-in controller in combination with the voltage stabilizing unit, and also improve the flexibility and convenience of motor over-temperature protection.

[0058] More optionally, if the voltage stabilizing unit 106 may include a three-terminal voltage regulator of model TL431, the thermistor 102 may include an NTC thermistor 102, and the control switch 108 may include an NPN transistor, the base of the NPN transistor serves as the control terminal of the control switch 108, and the emitter of the NPN transistor serves as the output terminal of the control switch 108, connected to the signal input terminal of the controller 110. The collector of the NPN transistor is grounded.

[0059] If the voltage stabilizing unit 106 may include a three-terminal voltage regulator of model TL431, the thermistor 102 may include a PTC thermistor 102, and the control switch 108 may include a PNP transistor, the base of the PNP transistor 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, connected to the signal input terminal of the controller 110. The emitter of the NPN transistor is grounded.

[0060] Therefore, by adapting and setting the control relationship according to different forms of the voltage stabilizing unit, the control switch and thermistor, it is helpful to improve the reliability and flexibility of the control of the motor overtemperature protection, and also improve the convenience of the motor overtemperature protection operation.

[0061] In an optional example, the voltage stabilizing unit 106 can also be used to be in a conducting state when the current temperature does not reach the preset over-temperature protection point of the switch tube, so as to control the control switch 108 to be turned off in combination with the voltage dividing branch and output a high-level signal to the controller 110 of the motor, so that the controller 110 can control the normal operation of the motor according to the high-level signal. Figure 2 As shown in the figure, when the temperature of the switch tube does not exceed the safe range, the resistance of the NTC increases, the TL431 is turned on, Q1 is turned off, the FO outputs a high level to the MCU, and the motor operates normally. When the temperature of the switch tube (such as the switch tube Q1) does not reach the over-temperature protection point during operation, the resistance of the NTC resistor increases, the voltage drop of the resistor divider increases, and the voltage input to the adjustable three-terminal regulator is greater than 2.5V. At this time, the TL431 is turned on, the transistor Q1 is turned off, the FO outputs a high level to the MUC, and the MCU sends a control signal to make the motor operate normally.

[0062] Therefore, when the current temperature of the motor's switching tube has not reached the over-temperature protection point, the voltage stabilizing unit is turned on, and the voltage divider branch formed by the thermistor and the voltage divider resistor in series is used to turn off the control switch and output a high-level signal to the built-in controller of the motor, so that the built-in controller can operate the motor normally according to the high-level signal, thereby avoiding false protection of the motor, reducing the false protection rate, and improving the reliability of the motor operation and the reliability of over-temperature protection.

[0063] In an optional example, the device may further include: at least one of a first shunt resistor (such as the shunt resistor R2 ) and a second shunt resistor (such as the shunt resistor R3 ).

[0064] For example: Figure 2 In the figure, R2 and R3 are current limiting resistors.

[0065] In an optional example, the first shunt resistor is arranged between the control end of the control switch 108 and a preset power supply, and can be used to protect the voltage stabilizing unit 106 and the control switch 108 (for example: to perform shunt control on the control end of the control switch 108).

[0066] In an optional example, the second shunt resistor is arranged between the output end of the control switch 108 and a preset power supply, and can be used to protect the voltage stabilizing unit 106 and the control switch 108 (for example: to perform shunt control on the output end of the control switch 108).

[0067] For example: Figure 2 As shown, current limiting resistors R2, R3, etc. can prevent Q1 and TL431 from being damaged due to excessive current when they are turned on.

[0068] Therefore, the adaptive setting of the shunt resistor is helpful to improve the safety of the motor over-temperature protection control, thereby better ensuring the reliability and accuracy of the motor over-temperature protection control.

[0069] A large number of tests have verified that the technical solution of this embodiment can effectively solve the failure of the DC motor caused by the burning of the switching tube by adding a protection circuit for detecting the temperature of the switching tube, thereby improving the protection reliability.

[0070] According to an embodiment of the present invention, a motor corresponding to the over-temperature protection device of the motor is also provided. The motor may include: the over-temperature protection device of the motor described above.

[0071] In an optional implementation, considering that the switch tube used in the built-in controller of the brushless DC motor will generate serious heat during high-speed switching on and off, 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 protection circuit for the switch tube, which can effectively solve the failure of the DC motor caused by the burning of the switch tube.

[0072] 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 a protective shutdown, thereby avoiding the switch tube from burning out and causing the motor to fail. In other words, the present invention proposes a high-precision over-temperature protection circuit, which can effectively detect the temperature of the switch tube and accurately perform a protective shutdown, thereby avoiding the switch tube from burning out and causing the motor to fail, thereby effectively reducing the after-sales defective rate of the motor and improving the reliability and safety of the brushless DC motor.

[0073] In an optional specific example, the solution of the present invention, such as Figure 2 As shown in the figure, the temperature of the switch tube is detected by placing an NTC thermistor near the switch tube. The thermistor NTC is affected by the temperature, and its resistance changes to control the opening and closing of the adjustable three-terminal regulator (such as TL431, a parallel voltage regulator integrated circuit), thereby controlling the on and off of the transistor Q1. When the temperature of the switch tube (such as transistor Q1) exceeds the safe range, the NTC resistance decreases, TL431 is turned off, Q1 is turned on, FO (such as the emitter of 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 opening and closing of the transistor to perform FO high and low levels to realize motor over-temperature protection. Since the Vbe on-voltage of the general transistor is 0.7V~1.0V, the on-voltage voltage range is large, which may cause the motor to be misprotected or untimely protected. TL431 has a precise on-state voltage, so using an adjustable three-terminal regulator (such as TL431) for motor over-temperature protection can achieve precise shutdown of the brushless DC motor when the switch tube temperature reaches a certain value.

[0074] in, Figure 2 In the figure, Q1 is a transistor, and the high and low levels of FO output are controlled by controlling the on and off of the transistor Q1. TL431 is an adjustable three-terminal regulator, NTC is a thermistor, R1 is a voltage divider resistor, and the over-temperature protection point of the switch tube can be set by calculating its resistance value; R2 and R3 are current limiting resistors.

[0075] Specifically, the specific working principle of the present invention is described as follows:

[0076] When the temperature of the switch tube (such as the switch tube Q1) reaches the over-temperature protection point (such as the set safety range) during operation, the resistance of the NTC resistor decreases, and the voltage drop of the resistor divider decreases, causing the input voltage of the adjustable three-terminal regulator to be less than 2.5V. At this time, TL431 is in the off state, the transistor Q1 is turned on, FO outputs a low level to MUC, and the MCU sends a control signal to stop the motor.

[0077] When the temperature of the switch tube (such as the switch tube Q1) does not reach the over-temperature protection point during operation, the resistance of the NTC resistor increases, the voltage drop of the resistor divider increases, and the voltage input to the adjustable three-terminal regulator is greater than 2.5V. At this time, TL431 is on, the transistor Q1 is cut off, FO outputs a high level to MUC, and the MCU sends a control signal to make the motor operate normally.

[0078] The temperature range of the switching tubes currently in use is generally -55°C--150°C. In order to make the switching tubes work within a reliable temperature range, the temperature protection point needs to be set in combination with the motor power and actual tests during design.

[0079] For example: Set the NTC sensing temperature to 110℃ for protection. You can find the NTC resistance value R0 corresponding to the temperature of 110℃ according to the NTC specification sheet used. Since the reference voltage of the adjustable three-terminal regulator TL431 is 2.5V, it is in the on state when the input voltage of the switching power supply exceeds the upper limit voltage, and the corresponding resistance value of R1 can be calculated:

[0080]

[0081]

[0082] The advantage of this circuit is that by selecting the appropriate R1 resistance value, the motor can be accurately and timely shut down at the set over-temperature protection point for protection; according to the above calculation formula, assuming that VDD is 5V, and the NTC resistor model is 103KT1608T, when the temperature is 110℃, the NTC resistance is 770Ω, and the R1 resistance can be calculated to be 770Ω.

[0083] 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.

[0084] In an alternative example, for the actual application of the over-temperature protection circuit, Q1 in the circuit can use a PNP transistor, and the thermistor can choose a PTC, and the on and off conditions can be reset by setting the peripheral circuit to achieve the same function.

[0085] Since the processing and functions implemented by the motor of this embodiment are basically corresponding to the aforementioned Figure 1 to Figure 2 The embodiments, principles and examples of the device shown are as follows. Therefore, for matters not fully described in the description of this embodiment, reference can be made to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be given here.

[0086] A large number of tests have verified that the technical solution of the present invention can be used to effectively detect the temperature of the switch tube and accurately perform protection shutdown, thereby avoiding motor failure caused by burning of the switch tube, thereby improving the reliability of protection and the safety of motor operation.

[0087] According to an embodiment of the present invention, a method for over-temperature protection of a motor corresponding to the over-temperature protection device of the motor is also provided. Figure 3 The flow chart of an embodiment of the method of the present invention is shown in FIG. The over-temperature protection method of the motor may include: steps S110 to S130.

[0088] At step S110, the current temperature of the switch tube of the motor can be sensed by the thermistor 102. The thermistor 102 is arranged within a preset distance of the switch tube of the motor (such as the switch tube used by the built-in controller 110 of the brushless DC motor).

[0089] At step S120, the voltage-dividing branch formed by the voltage-dividing resistor 104 and the thermistor 102 connected in series is used to divide the preset power supply to achieve 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 connected in series between a preset power supply (such as a DC power supply VDD) and a ground signal (such as a GND signal).

[0090] At step S130, when the current temperature reaches the preset over-temperature protection point of the switch tube, the voltage stabilizing unit 106 is in the off state, so as to control the control switch 108 to conduct and output a low-level signal in combination with the voltage dividing branch, so as to control the motor to stop according to the low-level signal. Figure 2 As shown in the figure, when the temperature of the switch tube (such as transistor Q1) exceeds the safe range, the resistance of the NTC decreases, the TL431 is turned off, Q1 is turned on, and the 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 (such as the switch tube Q1) reaches the over-temperature protection point (such as the set safe range) during operation, the resistance of the NTC resistor decreases, and the voltage drop of the resistor divider decreases, causing the input voltage of the adjustable three-terminal regulator to be less than 2.5V. At this time, the TL431 is turned off, 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.

[0091] For example: During the specific implementation process, when the current temperature reaches the preset over-temperature protection point of the switch tube, a reminder message of over-temperature of the switch tube can be initiated, such as by voice reminder message, buzzer alarm reminder, display screen display, etc.

[0092] For example: adding a temperature detection protection circuit for the switch tube can effectively detect the temperature of the switch tube and accurately shut down the machine for protection, avoiding motor failure caused by the switch tube burning out, thereby effectively solving the DC motor failure caused by the switch tube burning out. For example: the temperature of the switch tube can be effectively detected and accurately shut down the machine for protection, avoiding motor failure caused by the switch tube burning out, which can effectively reduce the after-sales defective rate of the motor and improve the reliability and safety of the brushless DC motor.

[0093] Therefore, the current temperature of the switch tube of the built-in controller of the motor is sensed by the thermistor, so that the voltage stabilizing unit is in the off state, and the voltage dividing branch formed by the thermistor and the voltage dividing resistor in series is combined to turn on the control switch and output a low-level signal to the built-in controller of the motor, so that the built-in controller shuts down the motor according to the low-level signal, thereby reliably realizing over-temperature protection of the motor, and the timeliness and accuracy of the protection are guaranteed.

[0094] In an optional embodiment, the present invention may further include: when the current temperature does not reach the preset over-temperature protection point of the switch tube, the voltage stabilizing unit 106 is in a conducting state, so as to control the control switch 108 to be turned off in combination with the voltage dividing branch and output a high level signal, so as to control the normal operation of the motor according to the high level signal. Figure 2 As shown in the figure, when the temperature of the switch tube does not exceed the safe range, the resistance of the NTC increases, the TL431 is turned on, Q1 is turned off, the FO outputs a high level to the MCU, and the motor operates normally. When the temperature of the switch tube (such as the switch tube Q1) does not reach the over-temperature protection point during operation, the resistance of the NTC resistor increases, the voltage drop of the resistor divider increases, and the voltage input to the adjustable three-terminal regulator is greater than 2.5V. At this time, the TL431 is turned on, the transistor Q1 is turned off, the FO outputs a high level to the MUC, and the MCU sends a control signal to make the motor operate normally.

[0095] Therefore, when the current temperature of the motor's switching tube has not reached the over-temperature protection point, the voltage stabilizing unit is turned on, and the voltage divider branch formed by the thermistor and the voltage divider resistor in series is used to turn off the control switch and output a high-level signal to the built-in controller of the motor, so that the built-in controller can operate the motor normally according to the high-level signal, thereby avoiding false protection of the motor, reducing the false protection rate, and improving the reliability of the motor operation and the reliability of over-temperature protection.

[0096] In an optional embodiment, it may also include: protecting the voltage stabilizing unit 106 and the control switch 108 through a first shunt resistor (for example, shunt control is performed on the control end of the control switch 108); and / or, protecting the voltage stabilizing unit 106 and the control switch 108 through a second shunt resistor (for example, shunt control is performed on the output end of the control switch 108).

[0097] For example: Figure 2 In the circuit, 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.

[0098] Therefore, the adaptive setting of the shunt resistor is helpful to improve the safety of the motor over-temperature protection control, thereby better ensuring the reliability and accuracy of the motor over-temperature protection control.

[0099] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned motor, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0100] A large number of tests have verified that the technical solution of the present invention can effectively detect the temperature of the switch tube and accurately perform a protective shutdown to avoid motor failure caused by burning of the switch tube, which can effectively reduce the after-sales defective rate of the motor and improve the reliability and safety of the brushless DC motor.

[0101] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0102] 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 variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. An over-temperature protection device for a motor, characterized in that: include: A thermistor (102), a voltage-dividing resistor (104), a voltage-stabilizing unit (106) and a control switch (108); the control switch (108) comprises: an NPN transistor or a PNP transistor; wherein: The thermistor (102) is used to sense the current temperature of the switch tube of the motor; the thermistor (102) is arranged within a preset distance of the switch tube of the motor; the switch tube of the motor comprises: a switch tube used by a built-in controller (110) of a brushless DC motor; The voltage-dividing resistor (104) is connected in series with the thermistor (102) to form a voltage-dividing branch for a preset power supply, so as to realize voltage-dividing control of the voltage stabilizing unit (106) and the control switch (108); the over-temperature protection point of the switch tube of the motor is set by calculating the resistance value of the voltage-dividing resistor (104); in order to make the switch tube of the motor work within a reliable temperature range, it is necessary to set the temperature protection point in combination with the power of the motor and actual testing; by determining the resistance value of the voltage-dividing resistor (104), the motor is reliably shut down at the preset over-temperature protection point of the motor; The voltage stabilizing unit (106) is used to be in a shut-down state when the current temperature reaches a preset over-temperature protection point of the switch tube, so as to control the control switch (108) to be turned on in combination with the voltage dividing branch and 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; The voltage stabilizing unit (106) is also used to be in a conducting state when the current temperature does not reach the preset over-temperature protection point of the switch tube, so as to control the control switch (108) to be turned off in combination with the voltage dividing branch and output a high-level signal to the controller (110), so that the controller (110) controls the normal operation of the motor according to the high-level signal.

2. The device according to claim 1, characterized in that in, The resistance value of the voltage-dividing resistor (104) can be determined based on the voltage value of the power supply and the resistance value of the thermistor at the preset over-temperature protection point.

3. The device according to any one of claims 1-2, characterized in that: The voltage stabilizing unit (106) comprises: a three-terminal voltage stabilizer of model TL431; The reference terminal of the three-terminal regulator is connected to the common terminal of the thermistor (102) and the voltage-dividing resistor (104), and the cathode of the three-terminal regulator is connected to the control terminal of the control switch (108).

4. The device according to any one of claims 1-2, characterized in that: in, The thermistor (102) comprises: an NTC thermistor (102) or a PTC thermistor (102).

5. The device according to claim 3, characterized in that in, The thermistor (102) comprises: an NTC thermistor (102) or a PTC thermistor (102).

6. The device according to claim 4, characterized in that in, If the voltage stabilizing unit (106) includes a three-terminal voltage stabilizer of model TL431, the thermistor (102) includes an NTC thermistor (102), and the control switch (108) includes an NPN transistor, then the base of the NPN transistor serves as the control end of the control switch (108), and the emitter of the NPN transistor serves as the output end of the control switch (108), connected to the signal input end of the controller (110); If the voltage stabilizing unit (106) includes a three-terminal voltage stabilizer of model TL431, the thermistor (102) includes a PTC thermistor (102), and the control switch (108) includes a PNP transistor, then the base of the PNP transistor serves as the control end of the control switch (108), and the collector of the PNP transistor serves as the output end of the control switch (108), connected to the signal input end of the controller (110).

7. The device according to claim 5, characterized in that in, If the voltage stabilizing unit (106) includes a three-terminal voltage stabilizer of model TL431, the thermistor (102) includes an NTC thermistor (102), and the control switch (108) includes an NPN transistor, then the base of the NPN transistor serves as the control end of the control switch (108), and the emitter of the NPN transistor serves as the output end of the control switch (108), connected to the signal input end of the controller (110); If the voltage stabilizing unit (106) includes a three-terminal voltage stabilizer of model TL431, the thermistor (102) includes a PTC thermistor (102), and the control switch (108) includes a PNP transistor, then the base of the PNP transistor serves as the control end of the control switch (108), and the collector of the PNP transistor serves as the output end of the control switch (108), connected to the signal input end of the controller (110).

8. The device according to any one of claims 1, 2, 5-7, characterized in that: Also includes: At least one of the first shunt resistor and the second shunt resistor; wherein, The first shunt resistor is arranged between the control end 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 end 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).

9. The device according to claim 3, characterized in that Also includes: At least one of the first shunt resistor and the second shunt resistor; wherein, The first shunt resistor is arranged between the control end 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 end 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).

10. The device according to claim 4, characterized in that Also includes: At least one of the first shunt resistor and the second shunt resistor; wherein, The first shunt resistor is arranged between the control end 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 end 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).

11. A motor, characterized in that: include: An over-temperature protection device for a motor as described in any one of claims 1 to 10.

12. An over-temperature protection method for a motor as claimed in claim 11, characterized in that: include: Using a thermistor (102) to sense the current temperature of the switch tube of the motor; A voltage dividing branch formed by a voltage dividing resistor (104) and a thermistor (102) connected in series is used to divide the voltage of a preset power supply, thereby achieving voltage division control of a voltage stabilizing unit (106) and a control switch (108); Through the voltage stabilizing unit (106), when the current temperature reaches the preset over-temperature protection point of the switch tube, the switch is in a shut-off state, and the control switch (108) is controlled to be turned on in combination with the voltage dividing branch to output a low-level signal, thereby controlling the motor to stop according to the low-level signal.

13. The method according to claim 12, characterized in that Also includes: Through the voltage stabilizing unit (106), when the current temperature does not reach the preset over-temperature protection point of the switch tube, the voltage stabilizing unit (106) is in an on state, so as to control the control switch (108) to be turned off in combination with the voltage dividing branch and output a high-level signal, thereby achieving the control of the normal operation of the motor according to the high-level signal.

14. The method according to claim 12 or 13, characterized in that Also includes: The voltage stabilizing unit (106) and the control switch (108) are protected by a first shunt resistor; and / or, The second shunt resistor is used to protect the voltage stabilizing unit (106) and the control switch (108).

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