CN110557058B - Starting protection circuit of direct-current brushless motor - Google Patents
Starting protection circuit of direct-current brushless motor Download PDFInfo
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- CN110557058B CN110557058B CN201910809583.5A CN201910809583A CN110557058B CN 110557058 B CN110557058 B CN 110557058B CN 201910809583 A CN201910809583 A CN 201910809583A CN 110557058 B CN110557058 B CN 110557058B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/0816—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors concerning the starting sequence, e.g. limiting the number of starts per time unit, monitoring speed during starting
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/085—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/085—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load
- H02H7/0852—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load directly responsive to abnormal temperature by using a temperature sensor
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/20—Arrangements for starting
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Emergency Protection Circuit Devices (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
The invention relates to a motor control system, in particular to a starting protection circuit of a direct-current brushless motor; the technical problem of logic errors caused by poor operation of devices due to overlarge starting current when most of existing direct current brushless motor starting circuits directly start motors is solved. A starting protection method of a direct current brushless motor comprises the following steps: step 1) setting a short-circuit protection current limit value A and an overload protection current limit value B; step 2) setting a board-level temperature limit value C; step 3), starting a motor; step 4), measuring the current value on the power supply main line of the direct current brushless motor; step 5) collecting a current signal, and judging whether the current signal value reaches a short-circuit protection current limit value A or not; step 6) judging whether the current signal value reaches an overload protection current limit value B; and 7) collecting a board-level temperature value, and judging whether the temperature value reaches a board-level temperature limit value C. Meanwhile, the invention also provides a starting protection circuit of the direct current brushless motor.
Description
Technical Field
The invention relates to a motor control system, in particular to a starting protection circuit of a direct-current brushless motor.
Background
A dc brushless motor is a device that converts dc electrical energy into mechanical energy. The dc brushless motor is classified into a dc brushless motor and a dc brush motor. The brushless DC motor is developed based on power switch technology and permanent magnet synchronous technology, and has no brush, no interface, no noise and long service life.
There are generally three ways to start a dc brushless motor: the first is step-down start, which consumes less energy and needs special power supply equipment; secondly, the armature loop series resistor is started, so that the starting energy consumption is large, and the armature loop series resistor is not suitable for frequent starting and stopping; the third is direct start, which needs no additional equipment and is convenient to start, but the start moment is accompanied with huge start current, which is easy to cause bad operation of devices and logic errors.
Most of existing direct current brushless motor starting circuits have the defect that when direct starting is carried out, due to the fact that starting current is too large, poor operation of devices is prone to being caused, and logic errors are caused.
Disclosure of Invention
The invention provides a starting protection circuit of a direct current brushless motor, aiming at solving the technical problem that logic errors are caused by poor operation of devices due to overlarge starting current when most of existing direct current brushless motor starting circuits directly start the motor.
The technical solution of the invention is as follows: a starting protection method of a direct current brushless motor is characterized by comprising the following steps:
step 1) setting a short-circuit protection current limit value A and an overload protection current limit value B, wherein A is larger than B;
step 2) setting a board-level temperature limit value C;
step 3), starting a motor;
step 4), measuring the current value on the power supply main line of the direct current brushless motor;
step 5) acquiring the current signal obtained in the step 4), and comparing the current signal with a short-circuit protection current limit value A; if the current signal value is larger than or equal to the short-circuit protection current limit value A, the circuit is disconnected; if the current signal value is smaller than the short-circuit protection current limit value A, entering a step 6);
step 6) comparing the current signal in the step 4) with an overload protection current limit value B; if the current signal value is greater than or equal to the overload protection current limit value B, the circuit is disconnected; if the current signal value is smaller than the overload protection current limit value B, entering a step 7);
step 7) collecting a board-level temperature value, comparing the temperature value with a board-level temperature limit value C, and if the temperature value is greater than or equal to the board-level temperature limit value C, disconnecting the circuit; if the temperature value is less than the board-level temperature limit value C, the circuit is closed continuously and the step 5) is performed.
Further, the method also comprises the step 8) of judging whether the motor needs to be restarted or not after the circuit is disconnected for a certain time, and if so, closing the circuit; if not, the circuit is kept disconnected.
Meanwhile, the invention also provides a starting protection circuit of the direct current brushless motor, which is characterized in that:
the overload protection circuit comprises a current acquisition circuit, a short-circuit protection circuit and an overload overtemperature protection circuit;
the input end of the current acquisition circuit is connected with the two ends of a current measuring resistor R1 on a power main channel, and the output end of the current acquisition circuit is connected with the input end of the short-circuit protection circuit, the input end of the overload and overtemperature protection circuit and the output end of the overload and overtemperature protection circuit in a common way; and the output end of the short-circuit protection circuit is used for connecting the switching circuit.
Further, the current acquisition circuit comprises a current measuring chip U1, a first RC filter circuit, a resistor R3, a resistor R4, a resistor R5 and a second RC filter circuit;
the positive input end IN + and the negative input end IN-of the current measuring chip U1 are respectively connected with two ends of a current measuring resistor R1; the output end OUT of the current measuring chip U1 is connected with one end of a resistor R5 and the input end of the second RC filter circuit; the other end of the resistor R5 is grounded; the output end of the second RC filter circuit is connected with the input end of the short-circuit protection circuit, the input end of the overload and overtemperature protection circuit and the output end of the overload and overtemperature protection circuit in a common way; a first reference level input end REF1 of the current measuring chip U1 is connected with one end of the resistor R4; a second reference level input end REF2 of the current-measuring chip U1 is connected with one end of the resistor R3; the other ends of the resistor R4 and the resistor R3 are both grounded; the input end of the first RC filter circuit is connected with the positive electrode of a power supply, and the output end of the first RC filter circuit is connected with the power supply input end VS of the current measuring chip U1; the ground end GND of the current-measuring chip U1 is grounded.
Further, the overload and overtemperature protection circuit comprises a first comparator U2A, a reverse voltage prevention voltage stabilizing diode D1, a third RC filter circuit, a fourth RC filter circuit, a resistor R8, a resistor R9, a resistor R11, a thermistor R12, a capacitor C4, a capacitor C6 and a capacitor C7;
the input end of the fourth RC filter circuit is connected to the output end of the second RC filter circuit, and the output end of the fourth RC filter circuit is connected to the positive input end of the first comparator U2A; one end of the resistor R8 is connected with the positive electrode of a power supply, and the other end of the resistor R8, the resistor R9 and the capacitor C4 are connected with the negative input end of the first comparator U2A in common; the output end of the first comparator U2A is connected with the common end of the thermistor R12, the capacitor C6 and the capacitor C7 and the anode of the anti-reverse voltage stabilizing diode D1; the other end of the resistor R12 is connected with the anode of the power supply after being connected with the resistor R11 in series; the other ends of the capacitor C6 and the capacitor C7 are both grounded; the cathode of the reverse voltage prevention voltage stabilizing diode D1 is connected with the input end of the short-circuit protection circuit; the input end of the third RC filter circuit is connected with the positive electrode of a power supply, and the output end of the third RC filter circuit is connected with the power supply input end of the first comparator U2A.
Further, the short-circuit protection circuit comprises a second comparator U2B, a first NAND gate U3A, a second NAND gate U3B, a third NAND gate U3C, a fourth NAND gate U3D, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, a resistor R22, a capacitor C9, a capacitor C10, a capacitor C11 and a capacitor C12;
the negative input end of the second comparator U2B is connected with the output end of the second RC filter circuit and the cathode of the reverse voltage prevention voltage stabilizing diode D1; one end of the resistor R13 is connected with the positive electrode of the power supply, the other end of the resistor R14 and one end of the capacitor C9 which are arranged in parallel are connected with one end of the resistor R14, and the other ends of the resistor R14 and the capacitor C9 are both connected with the positive input end of the second comparator U2B; the output end of the second comparator U2B is respectively connected with one input end of a resistor R15 and a fourth NAND gate U3D; the other end of the resistor R15 is connected with the anode of the power supply;
the other input end of the fourth nand gate U3D is respectively connected to the output end of the third nand gate U3C and one input end of the first nand gate U3A; the output end of the fourth NAND gate U3D is connected with one input end of the third NAND gate U3C;
the other input end of the third NAND gate U3C is connected with the common end of a resistor R17, a resistor R16 and a capacitor C10; the other end of the resistor R17 is connected with the anode of the power supply; the other end of the capacitor C10 is grounded; the other end of the resistor R16 is connected with the CPU;
the other input end of the first NAND gate U3A is connected with the common end of a resistor R19 and a resistor R18; the other end of the resistor R19 is grounded; the other end of the resistor R18 is connected with the CPU; the output end of the first NAND gate U3A is respectively connected with two input ends of the second NAND gate U3B; the power supply of the first NAND gate U3A is connected with the common end of the resistor R20 and the capacitor C11; the other end of the resistor R20 is connected with the positive electrode of the power supply; the other end of the capacitor C11 is grounded; the grounding end of the first NAND gate U3A is grounded;
the output end of the second NAND gate U3B is connected with the common end of the resistor R21, the resistor R22 and the capacitor C12; the other end of the resistor R21 is connected with the anode of the power supply; the other end of the capacitor C12 is grounded; the other end of the resistor R22 is used for connecting a switch circuit.
Further, the current measuring chip U1 is a current measuring chip with high common mode rejection ratio and low drift.
Further, the first RC filter circuit comprises a resistor R2 and a capacitor C1 arranged in series; the second RC filter circuit comprises a resistor R6 and a capacitor C2 which are arranged in series; the third RC filter circuit comprises a resistor R10 and a capacitor C5 which are arranged in series.
Further, the fourth RC filter circuit comprises a resistor R7, a capacitor C3, and a capacitor C8; the capacitor C3 and the capacitor C8 are connected in parallel and then connected in series with the resistor R7.
Further, the power supply is a +5V power supply.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention accurately acquires the voltage value on the main road of the motor by combining the current acquisition circuit, the overload overtemperature protection circuit and the short-circuit protection circuit, processes the voltage value, and automatically disconnects the circuit when the voltage value exceeds the overload protection limit value, thereby ensuring that the logic error caused by circuit burning or easily causing poor device operation due to overload can not be caused; when the instantaneous current is too large and exceeds the short-circuit protection limit value, the short-circuit protection circuit can be awakened to disconnect the circuit, and the circuit board can not be burnt.
2. The output end of the current acquisition circuit is provided with the RC filter circuit, so that the fluctuation of the motor at the moment of starting is processed, and the motor is prevented from being subjected to error protection due to instantaneous large current.
3. The current acquisition circuit adopts a current sensing amplification design with high common mode rejection ratio and low drift, can realize accurate current measurement, and does not cause output voltage to generate larger transient and corresponding recovery ripple waves.
4. The invention adopts the thermistor, and when the temperature reaches a protection value, the protection function can be easily achieved.
5. The invention realizes the control of the voltage on the power main channel through the combination of the comparator and the logic gate circuit, and the control is more reliable.
Drawings
FIG. 1 is a flow chart of the present invention.
FIG. 2 is a circuit diagram of a current acquisition circuit in an embodiment of the present invention;
FIG. 3 is a circuit diagram of an overload over-temperature protection circuit according to an embodiment of the present invention;
FIG. 4 is a diagram of a short-circuit protection circuit in an embodiment of the present invention;
Detailed Description
The invention is further described with reference to the following figures and specific embodiments.
Referring to fig. 1, the method for protecting the start of the dc brushless motor includes the following steps:
step 1) setting a short-circuit protection current limit value A and an overload protection current limit value B, wherein A is larger than B;
step 2) setting a board-level temperature limit value C;
step 3), starting a motor;
step 4), measuring the current value on the power supply main line of the direct current brushless motor;
step 5) acquiring the current signal obtained in the step 4), and comparing the current signal with a short-circuit protection current limit value A; if the current signal value is larger than or equal to the short-circuit protection current limit value A, the circuit is disconnected; if the current signal value is smaller than the short-circuit protection current limit value A, entering a step 6);
step 6) comparing the current signal in the step 4) with an overload protection current limit value B; if the current signal value is greater than or equal to the overload protection current limit value B, the circuit is disconnected; if the current signal value is smaller than the overload protection current limit value B, entering a step 7);
step 7) collecting a board-level temperature value, comparing the temperature value with a board-level temperature limit value C, and if the temperature value is greater than or equal to the board-level temperature limit value C, disconnecting the circuit; if the temperature value is less than the board-level temperature limit value C, the circuit is closed continuously and the step 5) is performed.
Step 8) after the circuit is disconnected for a certain time, judging whether the motor needs to be restarted, if so, closing the circuit; if not, the circuit is kept open.
Referring to fig. 2 to 4, the starting protection circuit of the dc brushless motor includes a current collection circuit, a short circuit protection circuit and an overload overtemperature protection circuit. The input end of the current acquisition circuit is connected with the two ends of a current measuring resistor R1 on the power main channel, and the output end of the current acquisition circuit is connected with the input end of the short-circuit protection circuit, the input end of the overload overtemperature protection circuit and the output end of the overload overtemperature protection circuit; the output end of the short-circuit protection circuit is used for connecting the switching circuit. The current sensing chip U1 is a current sensing chip with high common mode rejection ratio and low drift.
Referring to fig. 2, the current collecting circuit includes a current measuring chip U1, a first RC filter circuit, a resistor R3, a resistor R4, and a second RC filter circuit. The first RC filter circuit includes a resistor R2 and a capacitor C1 arranged in series. The second RC filter circuit includes a resistor R6 and a capacitor C2 arranged in series.
The positive input end IN + and the negative input end IN-of the current measuring chip U1 are respectively connected with two ends of the current measuring resistor R1; two ends of the current measuring resistor R1 are power supply main channels. The output end OUT of the current measuring chip U1 is connected with one end of a resistor R5 and the input end of a second RC filter circuit; the other end of the resistor R5 is grounded; the output end OUT of the current measuring chip U1 outputs an amplified voltage signal; the output end of the second RC filter circuit is connected with the input end of the short-circuit protection circuit, the input end of the overload and overtemperature protection circuit and the output end in common; a first reference level input end REF1 of the current measuring chip U1 is connected with one end of a resistor R4; a second reference level input end REF2 of the current measuring chip U1 is connected with one end of a resistor R3; the other ends of the resistor R4 and the resistor R3 are both grounded; the input end of the first RC filter circuit is connected with the positive electrode of a power supply, and the output end of the first RC filter circuit is connected with the power supply input end VS of the current measuring chip U1; the ground terminal GND of the current-measuring chip U1 is grounded. The power supply in this embodiment is a +5V power supply.
Referring to fig. 3, the overload and overtemperature protection circuit includes a first comparator U2A, a reverse voltage prevention voltage stabilizing diode D1, a third RC filter circuit, a fourth RC filter circuit, a resistor R8, a resistor R9, a resistor R11, a thermistor R12, a capacitor C4, a capacitor C6 and a capacitor C7. The third RC filter circuit includes a resistor R10 and a capacitor C5 arranged in series. The fourth RC filter circuit includes a resistor R7, a capacitor C3, and a capacitor C8.
One end of the resistor R7 is connected with the output end of the second RC filter circuit, and the other end of the resistor R7, the capacitor C3 and the capacitor C8 are connected with the positive input end of the first comparator U2A in common; the other ends of the capacitor C3 and the capacitor C8 are grounded; one end of the resistor R8 is connected with the positive electrode of the power supply, and the other end of the resistor R8, the resistor R9 and the capacitor C4 are connected with the negative input end of the first comparator U2A in common; the output end of the first comparator U2A is connected with the common end of the thermistor R12, the capacitor C6 and the capacitor C7 and the anode of the anti-reverse voltage stabilizing diode D1; the other end of the resistor R12 is connected with the anode of the power supply after being connected with the resistor R11 in series; the other ends of the capacitor C6 and the capacitor C7 are grounded; the cathode of the reverse voltage prevention voltage stabilizing diode D1 is connected with the input end of the short-circuit protection circuit.
Referring to fig. 4, the short-circuit protection circuit includes a second comparator U2B, a first nand gate U3A, a second nand gate U3B, a third nand gate U3C, a fourth nand gate U3D, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, a resistor R22, a capacitor C9, a capacitor C10, a capacitor C11, and a capacitor C12.
The negative input end of the second comparator U2B is connected with the output end of the second RC filter circuit and the cathode of the reverse voltage prevention voltage stabilizing diode D1; one end of the resistor R13 is connected with the positive electrode of the power supply, the other end of the resistor R14 and one end of the capacitor C9 which are arranged in parallel are connected with one end of the resistor R14, and the other ends of the resistor R14 and the capacitor C9 are both connected with the positive input end of the second comparator U2B; the output end of the second comparator U2B is respectively connected with one input end of a resistor R15 and a fourth NAND gate U3D; the other end of the resistor R15 is connected with the anode of the power supply.
The other input end of the fourth nand gate U3D is respectively connected to the output end of the third nand gate U3C and one input end of the first nand gate U3A; the output of the fourth nand gate U3D is connected to one of the inputs of the third nand gate U3C.
The other input end of the third NAND gate U3C is connected with the common end of the resistor R17, the resistor R16 and the capacitor C10; the other end of the resistor R17 is connected with the anode of the power supply; the other end of the capacitor C10 is grounded; the other end of the resistor R16 is used for connecting with the CPU.
The other input end of the first NAND gate U3A is connected with the common end of the resistor R19 and the resistor R18; the other end of the resistor R19 is grounded; the other end of the resistor R18 is connected with the CPU; the output end of the first NAND gate U3A is respectively connected with two input ends of the second NAND gate U3B; the power supply end of the first NAND gate U3A is connected with the common end of the resistor R20 and the capacitor C11; the other end of the resistor R20 is connected with the anode of the power supply; the other end of the capacitor C11 is grounded; the ground of the first nand gate U3A is grounded.
The output end of the second NAND gate U3B is connected with the common end of the resistor R21, the resistor R22 and the capacitor C12; the other end of the resistor R21 is connected with the anode of the power supply; the other end of the capacitor C12 is grounded; the other end of the resistor R22 is used for connecting a switch circuit.
Referring to fig. 2 to 4, the operation principle of the starting protection circuit of the dc brushless motor is as follows:
the current measuring chip U1 inputs the voltage at two ends of the current measuring resistor R1 on the power main channel and outputs an amplified voltage signal. The voltage signal is filtered by R6 and C2 (the filter circuit processes the interference signal, such as a cold start transient large current, and prevents the generation of misoperation), so as to obtain a voltage signal with the interference signal filtered out, the signal is divided into two paths, one path enters the short-circuit protection circuit through the negative input end of the second comparator U2B, and is compared with the short-circuit protection voltage limit value (which can be converted into a corresponding short-circuit protection current limit value a) of the positive input end of the second comparator U2B (the short-circuit protection current limit value a is determined according to the board-level heat dissipation and the motor load), and the signal output by the second comparator U2B and the first nand gate U3A, the second nand gate U3B, the third nand gate U3C and the fourth nand gate U3D jointly realize the control of the power trunk; the other path is filtered by a fourth RC filter circuit, enters an overload and overtemperature protection circuit from the positive input end of the first comparator U2A, and is compared with an overload protection voltage limit value (which can be converted into a corresponding overload protection current limit value B) of the negative input end of the first comparator U2A (the overload protection current limit value B is determined according to board-level heat dissipation and motor load). The output end of the first comparator U2A is provided with a thermistor R12, and when the board-level temperature reaches a board-level temperature limit value C, the protection function can be realized.
In this embodiment, when the second nand gate U3B outputs a high level, the whole circuit is turned on, and the motor can work normally; when the second nand gate U3B outputs a low level, the power supply of the whole motor is cut off.
At the moment of current power-up, when the input 2 pin of the first nand gate U3A is connected to the pull-down resistor, its input is low and outputs high, i.e. the second nand gate U3B outputs low, the circuit is disconnected. At this time, the master chip inputs a high level to R18 and a brief low level to R16. The pin 8 of the third nand gate U3C outputs high level, the pin 9 outputs low level, the pin 8 outputs high level is locked, meanwhile, the pin 2 of the first nand gate U3A is high level, the pin 3 is low level, the pin 6 is high level, and the power supply circuit of the motor is closed. If the circuit is abnormal, a short circuit occurs, and the like, which causes the output of pin 7 of the second comparator U2B to be at a low level, at this time, since pin 8 of the third nand gate U3C is at a high level, pin 11 of the fourth nand gate U3D is at a high level, and at this time, the master chip inputs a high level to one end of the R16, and pin 8 of the third nand gate U3C is pulled low. At this time, pin 3 of the first nand gate U3A is high, pin 6 of the second nand gate U3B is low, and the motor power supply is disconnected. At the moment, the main chip can detect the state of the motor at any moment and try to restart the motor, and at the moment, the logic state of the circuit is the same as the starting moment.
The above description is only an embodiment of the present invention, and is not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to other related technical fields, are included in the scope of the present invention.
Claims (5)
1. A DC brushless motor starts protection circuit which characterized in that:
the overload protection circuit comprises a current acquisition circuit, a short-circuit protection circuit and an overload overtemperature protection circuit;
the input end of the current acquisition circuit is connected with the two ends of a current measuring resistor R1 on a power main channel, and the output end of the current acquisition circuit is connected with the input end of the short-circuit protection circuit, the input end of the overload and overtemperature protection circuit and the output end of the overload and overtemperature protection circuit in a common way; the output end of the short-circuit protection circuit is used for being connected with the switching circuit;
the current acquisition circuit comprises a current measuring chip U1, a first RC filter circuit, a resistor R3, a resistor R4, a resistor R5 and a second RC filter circuit;
the positive input end IN + and the negative input end IN-of the current measuring chip U1 are respectively connected with two ends of a current measuring resistor R1; the output end OUT of the current measuring chip U1 is connected with one end of a resistor R5 and the input end of the second RC filter circuit; the other end of the resistor R5 is grounded; the output end of the second RC filter circuit is connected with the input end of the short-circuit protection circuit, the input end of the overload and overtemperature protection circuit and the output end of the overload and overtemperature protection circuit in a common way; a first reference level input end REF1 of the current measuring chip U1 is connected with one end of the resistor R4; a second reference level input end REF2 of the current-measuring chip U1 is connected with one end of the resistor R3; the other ends of the resistor R4 and the resistor R3 are both grounded; the input end of the first RC filter circuit is connected with the positive electrode of a power supply, and the output end of the first RC filter circuit is connected with the power supply input end VS of the current measuring chip U1; the grounding end GND of the current measuring chip U1 is grounded;
the overload overtemperature protection circuit comprises a first comparator U2A, an anti-reverse voltage stabilizing diode D1, a third RC filter circuit, a fourth RC filter circuit, a resistor R8, a resistor R9, a resistor R11, a thermistor R12, a capacitor C4, a capacitor C6 and a capacitor C7;
the input end of the fourth RC filter circuit is connected to the output end of the second RC filter circuit, and the output end of the fourth RC filter circuit is connected to the positive input end of the first comparator U2A; one end of the resistor R8 is connected with the positive electrode of a power supply, and the other end of the resistor R8, the resistor R9 and the capacitor C4 are connected with the negative input end of the first comparator U2A in common; the output end of the first comparator U2A is connected with the common end of the thermistor R12, the capacitor C6 and the capacitor C7 and the anode of the anti-reverse voltage stabilizing diode D1; the other end of the resistor R12 is connected with the anode of the power supply after being connected with the resistor R11 in series; the other ends of the capacitor C6 and the capacitor C7 are both grounded; the cathode of the reverse voltage prevention voltage stabilizing diode D1 is connected with the input end of the short-circuit protection circuit; the input end of the third RC filter circuit is connected with the positive electrode of a power supply, and the output end of the third RC filter circuit is connected with the power supply input end of the first comparator U2A;
the short-circuit protection circuit comprises a second comparator U2B, a first NAND gate U3A, a second NAND gate U3B, a third NAND gate U3C, a fourth NAND gate U3D, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, a resistor R22, a capacitor C9, a capacitor C10, a capacitor C11 and a capacitor C12;
the negative input end of the second comparator U2B is connected with the output end of the second RC filter circuit and the cathode of the reverse voltage prevention voltage stabilizing diode D1; one end of the resistor R13 is connected with the positive electrode of the power supply, the other end of the resistor R14 and one end of the capacitor C9 which are arranged in parallel are connected with one end of the resistor R14, and the other ends of the resistor R14 and the capacitor C9 are both connected with the positive input end of the second comparator U2B; the output end of the second comparator U2B is respectively connected with one input end of a resistor R15 and a fourth NAND gate U3D; the other end of the resistor R15 is connected with the anode of the power supply;
the other input end of the fourth nand gate U3D is respectively connected to the output end of the third nand gate U3C and one input end of the first nand gate U3A; the output end of the fourth NAND gate U3D is connected with one input end of the third NAND gate U3C;
the other input end of the third NAND gate U3C is connected with the common end of a resistor R17, a resistor R16 and a capacitor C10; the other end of the resistor R17 is connected with the anode of the power supply; the other end of the capacitor C10 is grounded; the other end of the resistor R16 is connected with the CPU;
the other input end of the first NAND gate U3A is connected with the common end of a resistor R19 and a resistor R18; the other end of the resistor R19 is grounded; the other end of the resistor R18 is connected with the CPU; the output end of the first NAND gate U3A is respectively connected with two input ends of the second NAND gate U3B; the power supply of the first NAND gate U3A is connected with the common end of the resistor R20 and the capacitor C11; the other end of the resistor R20 is connected with the positive electrode of the power supply; the other end of the capacitor C11 is grounded; the grounding end of the first NAND gate U3A is grounded;
the output end of the second NAND gate U3B is connected with the common end of the resistor R21, the resistor R22 and the capacitor C12; the other end of the resistor R21 is connected with the anode of the power supply; the other end of the capacitor C12 is grounded; the other end of the resistor R22 is used for connecting a switch circuit.
2. The starting protection circuit of a dc brushless motor according to claim 1, wherein: the current measuring chip U1 is a current measuring chip with high common mode rejection ratio and low drift.
3. The starting protection circuit of a dc brushless motor according to claim 2, wherein: the first RC filter circuit comprises a resistor R2 and a capacitor C1 which are arranged in series; the second RC filter circuit comprises a resistor R6 and a capacitor C2 which are arranged in series; the third RC filter circuit comprises a resistor R10 and a capacitor C5 which are arranged in series.
4. A dc brushless motor start protection circuit according to claim 3, wherein: the fourth RC filter circuit comprises a resistor R7, a capacitor C3 and a capacitor C8; the capacitor C3 and the capacitor C8 are connected in parallel and then connected in series with the resistor R7.
5. The starting protection circuit of a brushless dc motor according to claim 4, wherein: the power supply is a +5V power supply.
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| JPH01126131A (en) * | 1987-11-09 | 1989-05-18 | Fuji Electric Co Ltd | Overload detection circuit for rotational speed controller |
| KR101364204B1 (en) * | 2007-05-29 | 2014-02-17 | 엘지전자 주식회사 | Motor Driver System and method for protecting motor drive |
| CN102868340A (en) * | 2012-09-06 | 2013-01-09 | 苏州朗格电动车有限公司 | Low-voltage large-current alternating-current permanent magnet driving system for small electronic vehicle |
| CN103633624B (en) * | 2013-12-17 | 2017-02-01 | 北京天诚同创电气有限公司 | Comprehensive protection method for direct-drive permanent magnet wind driven generator |
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| CN108963350B (en) * | 2017-05-18 | 2020-09-25 | 深圳市乐得瑞科技有限公司 | Battery protection method and device |
| CN207964928U (en) * | 2018-02-12 | 2018-10-12 | 卡乐电子(苏州)有限责任公司 | A kind of current sampling circuit suitable for high pressure detection |
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