CN117031273A - Motor fault detection circuit - Google Patents
Motor fault detection circuit Download PDFInfo
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- CN117031273A CN117031273A CN202311019782.9A CN202311019782A CN117031273A CN 117031273 A CN117031273 A CN 117031273A CN 202311019782 A CN202311019782 A CN 202311019782A CN 117031273 A CN117031273 A CN 117031273A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
- G01R31/343—Testing dynamo-electric machines in operation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/18—Indicating phase sequence; Indicating synchronism
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Abstract
The invention relates to the technical field of motor faults, and provides a motor fault detection circuit which comprises a voltage conversion circuit, an inverse phase detection circuit and a main control unit, wherein the voltage conversion circuit is used for outputting square wave signals with the same frequency as three phases of electricity, the input end of the inverse phase detection circuit is connected with the output end of the voltage conversion circuit, the output end of the inverse phase detection circuit is connected with the main control unit, and the main control unit judges whether an inverse phase condition exists in the running process of a motor according to waveforms output by a trigger. Through the technical scheme, the problem of low motor reverse phase detection response speed in the related art is solved.
Description
Technical Field
The invention relates to the technical field of motor faults, in particular to a motor fault detection circuit.
Background
The motor plays a vital role in the production processes of industry, agriculture and the like in China, mechanical faults can occur in the motor in the long-term operation process, electrical faults can occur, common electrical faults include motor power failure, reverse phase and the like, when the reverse phase occurs in the power of the motor, the motor is easy to vibrate, noise and the like, and the motor is directly damaged if the reverse phase occurs in the power of the motor, so that the phase sequence detection of the motor is particularly important, and when the phase sequence fault occurs in the motor in the working process, the power is disconnected in time, so that the motor is prevented from being damaged. The existing motor reverse phase detection has the problem of low response speed, and when the motor fails in reverse phase, the power supply of the motor cannot be cut off in time.
Disclosure of Invention
The invention provides a motor fault detection circuit, which solves the problem of low motor reverse phase detection response speed in the related technology.
The technical scheme of the invention is as follows:
the motor fault detection circuit comprises a voltage conversion circuit, an inverse phase detection circuit and a main control unit, wherein the voltage conversion circuit is used for outputting square wave signals with the same frequency as three-phase electricity, the input end of the inverse phase detection circuit is connected with the output end of the voltage conversion circuit, the output end of the inverse phase detection circuit is connected with the main control unit, the inverse phase detection circuit comprises a NAND gate U1, a NAND gate U2, a NAND gate U3, a NAND gate U4, a NAND gate U5, a NAND gate U6 and a trigger U7,
the first input end of the NAND gate U2 is connected with a 5V power supply, the second input end of the NAND gate U2 is connected with a signal generator, the third input end of the NAND gate U2 is connected with the output end of the NAND gate U4, the output end of the NAND gate U2 is connected with the first input end of the NAND gate U1,
the second input end of the NAND gate U1 is connected with a 5V power supply, the third input end of the NAND gate U1 is connected with the output end of the NAND gate U3, the output end of the NAND gate U1 is connected with the first input end of the NAND gate U3, the second input end of the NAND gate U3 is connected with the second input end of the NAND gate U2, the third input end of the NAND gate U3 is connected with the first output end of the voltage conversion circuit, the output end of the NAND gate U3 is connected with the second input end of the NAND gate U4, the third input end of the NAND gate U4 is connected with the first output end of the voltage conversion circuit,
the output end of the NAND gate U3 is connected with the first input end of the NAND gate U6, the output end of the NAND gate U4 is connected with the first input end of the NAND gate U5,
the second input end of the NAND gate U6 is connected with a 5V power supply, the third input end of the NAND gate U6 is connected with the output end of the NAND gate U5, the output end of the NAND gate U6 is connected with the input end of the trigger U7, the output end of the NAND gate U6 is connected with the second input end of the NAND gate U5, the third input end of the NAND gate U5 is connected with the second input end of the NAND gate U2,
the clock end of the trigger U7 is connected with the second output end of the voltage conversion circuit, the reset end of the trigger U7 is connected with the second input end of the NAND gate U2, the set end of the trigger U7 is connected with a 5V power supply, and the output end of the trigger U7 is connected with the first input end of the main control unit.
Further, the invention also comprises a protection circuit, wherein the protection circuit comprises an optocoupler U17, a resistor R16, a triode Q1 and a relay K1, a first input end of the optocoupler U17 is connected with a 5V power supply, a second input end of the optocoupler U17 is connected with a first output end of the main control unit, a first output end of the optocoupler U17 is connected with a 12V power supply, a second output end of the optocoupler U17 is connected with a base electrode of the triode Q1 through the resistor R16, a collector electrode of the triode Q1 is connected with a first input end of the relay K1, a second input end of the relay K1 is connected with a 12V power supply, a normally closed end of the relay K1 is connected with a power supply system, a public end of the relay K1 is connected with a motor, and an emitter electrode of the triode Q1 is grounded.
Further, in the present invention, the voltage conversion circuit includes two branches with the same circuit structure, where any branch includes a transformer T1, a resistor R1, an optocoupler U10, a not gate U8 and a not gate U9, where a first input end of the transformer T1 is connected to the phase a, a second input end of the transformer T1 is connected to a zero line, a first output end of the transformer T1 is connected to a first input end of the optocoupler U10 through the resistor R1, a second output end of the optocoupler U10 is connected to a second output end of the transformer T1, a first output end of the optocoupler U10 is connected to a 5V power supply, a second output end of the optocoupler U10 is connected to an input end of the not gate U8, an output end of the not gate U8 is connected to an input end of the not gate U9, and an output end of the not gate U9 is connected to a third input end of the not gate U3 and the not gate U4.
Further, the invention also comprises a voltage detection circuit which comprises a resistor R4, a resistor R7, an operational amplifier U11, an operational amplifier U12, a resistor R8, a resistor R9, a diode D2 and a diode D3,
the in-phase input end of the operational amplifier U11 is connected with the first input end of the optocoupler U10 through the resistor R4, the anti-phase input end of the operational amplifier U11 is connected with the first end of the resistor R9, the first end of the resistor R9 is connected with a 5V power supply through the resistor R8, the second end of the resistor R9 is grounded, the output end of the operational amplifier U11 is connected with the anode of the diode D2, the cathode of the diode D2 is connected with the second input end of the main control unit, the anti-phase input end of the operational amplifier U12 is connected with the first input end of the optocoupler U10 through the resistor R7, the in-phase input end of the operational amplifier U12 is connected with the first end of the resistor R9, the output end of the operational amplifier U12 is connected with the anode of the diode D3, and the cathode of the diode D3 is connected with the third input end of the main control unit.
Further, the invention also comprises a temperature detection circuit, the temperature detection circuit comprises an operational amplifier U13, a thermistor RT, a resistor R10, a resistor R11, a resistor R3, a voltage stabilizer U15, a resistor RP1, an operational amplifier U14 and a resistor R12, wherein the non-inverting input end of the operational amplifier U13 is grounded, the inverting input end of the operational amplifier U13 is connected with the cathode of the voltage stabilizer U15 through the resistor R3, the anode of the voltage stabilizer U15 is grounded, the control electrode of the voltage stabilizer U15 is connected with the control end of the resistor RP1, the first end of the resistor RP1 is connected with a-5V power supply, the second end of the resistor RP1 is grounded, the output end of the operational amplifier U13 is connected with the inverting input end of the operational amplifier U13 through the thermistor RT, the non-inverting input end of the operational amplifier U14 is connected with the inverting input end of the operational amplifier U13 through the resistor R10, the non-inverting input end of the operational amplifier U14 is connected with the inverting input end of the operational amplifier U13 through the resistor R11, and the second end of the operational amplifier U14 is connected with the output end of the fourth end of the operational amplifier U14 through the output end of the resistor R14.
Further, a filter circuit is further provided between the output end of the operational amplifier U14 and the fourth input end of the main control unit, the filter circuit includes a resistor R13, a capacitor C2, a resistor R14, an operational amplifier U16, a capacitor C3 and a resistor R15, a first end of the resistor R13 is connected to the output end of the operational amplifier U14, a second end of the resistor R13 is grounded through the capacitor C2, a second end of the resistor R13 is connected to the inverting input end of the operational amplifier U16 through the resistor R14, the non-inverting input end of the operational amplifier U16 is grounded, the output end of the operational amplifier U16 is connected to the inverting input end of the operational amplifier U16 through the capacitor C3, the output end of the operational amplifier U16 is connected to the second end of the resistor R13 through the resistor R15, and the output end of the operational amplifier U16 is connected to the fourth input end of the main control unit.
The working principle and the beneficial effects of the invention are as follows:
the voltage conversion circuit is used for converting the phase A electricity and the phase B electricity into two paths of square wave signals respectively to be output, the frequencies of the two paths of square wave signals are the same as the frequencies of the corresponding phase A electricity and phase B electricity, the phase A electricity is taken as an example, the voltage conversion circuit outputs high level in the positive half cycle of the phase A electricity, the voltage conversion circuit outputs low level in the negative half cycle of the phase A electricity, the reverse phase detection circuit detects whether the motor has reverse phase faults according to the square wave signals output by the voltage conversion circuit and sends the detection result to the main control unit in a digital signal mode, and the main control unit judges whether the motor has reverse phase faults in the working process according to the received digital signals.
In the positive phase sequence, the phase A electricity leads the phase B electricity by 120 degrees, the phase B electricity leads the phase C electricity by 120 degrees, and the phase C electricity leads the phase A electricity by 120 degrees. The signal generator is used for outputting a narrow pulse with the same frequency as the C phase, and when the C phase is in forward zero crossing, the signal generator outputs a low-level narrow pulse signal, and the other time is in high level. Specifically, the working principle of the reverse phase detection circuit is as follows:
when the phase a power is high, the third input ends of the nand gate U3 and the nand gate U4 are both high, and the second input end of the nand gate U2 is high, so that the nand gate U2 outputs low, the nand gate U1 outputs high, the nand gate U3 outputs low, the nand gate U4 outputs high, the nand gate U6 and the nand gate U5 form an RS flip-flop, the nand gate outputs high to the input end of the flip-flop U7, during the phase a power is high, the phase B power is changed from low to high, when the phase B power is low, the clock end of the flip-flop U7 is low, and therefore the flip-flop U7 outputs low, and when the phase B power is high, the flip-flop U7 outputs high. When the phase A electricity is low level, the NAND gate U3 and the NAND gate U4 both output high level, the NAND gate U6 outputs high level anyway, so the trigger U7 outputs high level, the phase C electricity positively crosses zero during the phase A electricity is low level, and the signal generator outputs a low level narrow pulse signal to the reset end of the trigger U7 when the phase C electricity positively crosses zero, and the output end of the trigger U7 is changed from high level to low level. When the phase A electricity is changed from low level to high level again, the process is repeated, so that when the phase sequence of the motor is normal, the main control unit receives a stable pulse signal, and the frequency of the pulse signal is the same as the frequency of the three-phase electricity.
In the reverse phase sequence, the phase B electricity leads the phase A electricity by 120 degrees, when the phase B electricity is in a high level, the phase A electricity is changed from a low level to a high level, and during the period, the NAND gate U6 always outputs a high level, so the trigger U7 outputs a high level signal to the main control unit. When the B phase electricity is at a high level, the C phase electricity positively crosses zero, the signal generator outputs a low-level narrow pulse signal to the reset end of the trigger U7, the trigger U7 outputs a low level, and when the B phase electricity is changed to a high level again, the trigger outputs a high level, so that the pulse signal output by the trigger U7 is opposite to the pulse signal output by the trigger U7 when the motor is in a positive phase sequence and a negative phase sequence, and therefore, the main control unit can judge whether the negative phase condition exists in the motor operation process according to the waveform output by the trigger.
Compared with the traditional analog circuit, the digital circuit has the advantages that the transmission speed is higher, the circuit works more stably, and the response speed of motor reverse phase detection is improved.
Drawings
The invention will be described in further detail with reference to the drawings and the detailed description.
FIG. 1 is a circuit diagram of an anti-phase detection circuit according to the present invention;
FIG. 2 is a waveform diagram of an anti-phase detection circuit according to the present invention;
FIG. 3 is a circuit diagram of the protection circuit of the present invention;
FIG. 4 is a circuit diagram of a voltage conversion circuit according to the present invention;
FIG. 5 is a circuit diagram of a voltage detection circuit according to the present invention;
FIG. 6 is a circuit diagram of a temperature detection circuit according to the present invention;
fig. 7 is a circuit diagram of a filter circuit according to the present invention.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
As shown in fig. 1-2, the embodiment provides a motor fault detection circuit, which comprises a voltage conversion circuit, an inverted phase detection circuit and a main control unit, wherein the voltage conversion circuit is used for outputting square wave signals with the same frequency as three phases, the input end of the inverted phase detection circuit is connected with the output end of the voltage conversion circuit, the output end of the inverted phase detection circuit is connected with the main control unit, the inverted phase detection circuit comprises a nand gate U1, a nand gate U2, a nand gate U3, a nand gate U4, a nand gate U5, a nand gate U6 and a trigger U7, the first input end of the nand gate U2 is connected with a 5V power supply, the second input end of the nand gate U2 is connected with a signal generator, the third input end of the nand gate U2 is connected with the output end of the nand gate U4, the output end of the nand gate U2 is connected with the first input end of the nand gate U1, the second input end of the nand gate U1 is connected with the 5V power supply, the third input end of the NAND gate U1 is connected with the output end of the NAND gate U3, the output end of the NAND gate U1 is connected with the first input end of the NAND gate U3, the second input end of the NAND gate U3 is connected with the second input end of the NAND gate U2, the third input end of the NAND gate U3 is connected with the first output end of the NAND gate U4, the third input end of the NAND gate U4 is connected with the first output end of the voltage conversion circuit, the output end of the NAND gate U3 is connected with the first input end of the NAND gate U6, the output end of the NAND gate U4 is connected with the first input end of the NAND gate U5, the second input end of the NAND gate U6 is connected with a 5V power supply, the third input end of the NAND gate U6 is connected with the output end of the NAND gate U5, the output end of the NAND gate U6 is connected with the input end of the trigger U7, the output end of the NAND gate U6 is connected with the second input end of the NAND gate U5, the third input end of the NAND gate U5 is connected with the second input end of the NAND gate U2, the clock end of the trigger U7 is connected with the second output end of the voltage conversion circuit, the reset end of the trigger U7 is connected with the second input end of the NAND gate U2, the set end of the trigger U7 is connected with a 5V power supply, and the output end of the trigger U7 is connected with the first input end of the main control unit.
In this embodiment, the voltage conversion circuit is configured to convert the a-phase electricity and the B-phase electricity into two paths of square wave signals respectively for output, where the frequencies of the two paths of square wave signals are the same as the frequencies of the corresponding a-phase electricity and B-phase electricity, and taking the a-phase electricity as an example, the voltage conversion circuit outputs a high level at a positive half cycle of the a-phase electricity, and outputs a low level at a negative half cycle of the a-phase electricity, and the reverse phase detection circuit detects whether the motor has a reverse phase fault according to the square wave signals output by the voltage conversion circuit, and sends the detection result to the main control unit in a digital signal manner, where the main control unit determines whether the motor has the reverse phase fault in the working process according to the received digital signal.
In the positive phase sequence, the phase A electricity leads the phase B electricity by 120 degrees, the phase B electricity leads the phase C electricity by 120 degrees, and the phase C electricity leads the phase A electricity by 120 degrees. The signal generator is used for outputting a narrow pulse with the same frequency as the C phase, and when the C phase is in forward zero crossing, the signal generator outputs a low-level narrow pulse signal, and the other time is in high level. Specifically, the working principle of the reverse phase detection circuit is as follows:
when the phase a power is high, the third input ends of the nand gate U3 and the nand gate U4 are both high, and the second input end of the nand gate U2 is high, so that the nand gate U2 outputs low, the nand gate U1 outputs high, the nand gate U3 outputs low, the nand gate U4 outputs high, the nand gate U6 and the nand gate U5 form an RS flip-flop, the nand gate outputs high to the input end of the flip-flop U7, during the phase a power is high, the phase B power is changed from low to high, when the phase B power is low, the clock end of the flip-flop U7 is low, and therefore the flip-flop U7 outputs low, and when the phase B power is high, the flip-flop U7 outputs high.
When the phase A electricity is low level, the NAND gate U3 and the NAND gate U4 both output high level, the NAND gate U6 outputs high level anyway, so the trigger U7 outputs high level, the phase C electricity positively crosses zero during the phase A electricity is low level, and the signal generator outputs a low level narrow pulse signal to the reset end of the trigger U7 when the phase C electricity positively crosses zero, and the output end of the trigger U7 is changed from high level to low level. When the phase A electricity is changed from low level to high level again, the process is repeated, so that when the phase sequence of the motor is normal, the main control unit receives a stable pulse signal, and the frequency of the pulse signal is the same as the frequency of the three-phase electricity.
In the reverse phase sequence, the phase B electricity leads the phase A electricity by 120 DEG, when the phase B electricity is high, the phase A electricity is changed from low level to high level, during the period, the NAND gate U6 always outputs high level, so the trigger U7 outputs high level signals to the main control unit,
when the B phase electricity is at a high level, the C phase electricity positively crosses zero, the signal generator outputs a low-level narrow pulse signal to the reset end of the trigger U7, the trigger U7 outputs a low level, when the B phase electricity is changed to a high level again, the trigger outputs a high level, therefore, when the three-phase electricity is in positive sequence and when the three-phase electricity is in reverse sequence, the pulse signal output by the trigger U7 is opposite, and therefore, the main control unit can judge whether the reverse phase condition exists in the operation process of the motor according to the waveform output by the trigger.
The reverse phase detection circuit in the embodiment is a digital circuit, and compared with the traditional analog circuit, the digital circuit has higher transmission speed and more stable circuit operation, thereby improving the response speed of motor reverse phase detection.
In fig. 2, UA and UB are waveforms after phase a and phase B are converted into square waves, respectively; j1 is a waveform output by a signal generator, and the frequency of the low-level narrow pulse signal output by the signal generator is the same as the frequency of C-phase electricity; q is the waveform output by the flip-flop U7, and in this embodiment, a D flip-flop is used as the flip-flop U7.
As shown in fig. 3, the embodiment further includes a protection circuit, where the protection circuit includes an optocoupler U17, a resistor R16, a triode Q1, and a relay K1, where a first input end of the optocoupler U17 is connected to a 5V power supply, a second input end of the optocoupler U17 is connected to a first output end of the master control unit, a first output end of the optocoupler U17 is connected to a 12V power supply, a second output end of the optocoupler U17 is connected to a base electrode of the triode Q1 through the resistor R16, a collector electrode of the triode Q1 is connected to a first input end of the relay K1, a second input end of the relay K1 is connected to a 12V power supply, a normally closed end of the relay K1 is connected to a power supply system, a common end of the relay K1 is connected to a motor, and an emitter electrode of the triode Q1 is grounded.
When the reverse phase condition occurs in the operation process of the motor, the power supply system of the motor should be immediately disconnected so as to prevent the motor from being damaged, and therefore, a protection circuit is added in the embodiment.
Specifically, the working principle of the protection circuit is as follows: when the motor operates normally, the first input end of the main control unit outputs a high-level signal, the optocoupler U17 is cut off, the triode Q1 is cut off, the relay K1 does not act, the motor is normally connected with the power supply system, when an inverted phase occurs in the motor operation process, the first input end of the main control unit outputs a low-level signal, the optocoupler U17 is conducted, the triode Q1 is also conducted, the point of the relay K1 is sucked, the normally closed contact of the relay K1 is disconnected, the motor is disconnected from the power supply system, and the motor stops operating.
As shown in fig. 4, the voltage conversion circuit in this embodiment includes two branches with the same circuit structure, where any branch includes a transformer T1, a resistor R1, an optocoupler U10, an inverter U8 and an inverter U9, a first input end of the transformer T1 is connected to the phase a, a second input end of the transformer T1 is connected to a zero line, a first output end of the transformer T1 is connected to a first input end of the optocoupler U10 through the resistor R1, a second output end of the optocoupler U10 is connected to a second output end of the transformer T1, a first output end of the optocoupler U10 is connected to a 5V power supply, a second output end of the optocoupler U10 is connected to an input end of the inverter U8, an output end of the inverter U8 is connected to an input end of the inverter U9, and an output end of the inverter U9 is connected to a third input end of the inverter U3 and the inverter U4.
In this embodiment, the voltage conversion circuit is configured to convert an ac voltage signal of a phase a power and a phase B power into a square wave signal, where the voltage conversion circuit includes two branches with the same circuit structure, and the branches are respectively used to connect the phase a power and the phase B power, and taking the phase a power as an example, the phase a power is reduced by the transformer T1 and then converts a high-voltage ac power into a low-voltage ac power, when the ac power is in a positive half cycle, the optocoupler U10 is turned on, and the optocoupler U10 outputs a high-level signal; when the alternating current is in the negative half cycle, the optical coupler U10 is cut off, and the optical coupler U10 outputs a low-level signal. The NOT gate U8 and the NOT gate U9 play a role in waveform shaping, so that the square wave signal is more stable.
As shown in fig. 5, the embodiment further includes a voltage detection circuit, where the voltage detection circuit includes a resistor R4, a resistor R7, an operational amplifier U11, an operational amplifier U12, a resistor R8, a resistor R9, a diode D2, and a diode D3, where the in-phase input end of the operational amplifier U11 is connected to the first input end of the optocoupler U10 through the resistor R4, the opposite-phase input end of the operational amplifier U11 is connected to the first end of the resistor R9, the first end of the resistor R9 is connected to a 5V power supply through the resistor R8, the second end of the resistor R9 is grounded, the output end of the operational amplifier U11 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the second input end of the master control unit, the opposite-phase input end of the operational amplifier U12 is connected to the first input end of the optocoupler U10 through the resistor R7, the output end of the operational amplifier U12 is connected to the anode of the diode D3, and the cathode of the diode D3 is connected to the third input end of the master control unit.
The electric faults of the motor are over-voltage and under-voltage besides reverse phase, when the motor is over-voltage, the motor running current is overlarge, the temperature of a motor winding is increased when the motor is over-voltage and is operated for a long time, the service life of the motor is influenced, and when the motor is in an under-voltage working state, the motor cannot be started normally. It is also important to detect the operating voltage of the motor.
And when the motor operation voltage is normal, the voltage of the non-inverting input end of the operational amplifier U11 is lower than the voltage of the inverting input end of the operational amplifier U11, the voltage of the non-inverting input end of the operational amplifier U12 is lower than the voltage of the inverting input end of the operational amplifier U12, and the operational amplifier U11 and the operational amplifier U12 output low-level signals to the main control unit at the same time.
When the motor running voltage is over-voltage, the voltage of the non-inverting input end of the operational amplifier U11 is larger than the voltage of the inverting input end of the operational amplifier U11, the operational amplifier U11 outputs a high-level signal to the second input end of the main control unit, and the operational amplifier U12 still outputs a low-level signal;
when the motor running voltage is under-voltage, the voltage of the non-inverting input end of the operational amplifier U12 is larger than the voltage of the inverting input end of the operational amplifier U12, the operational amplifier U12 outputs a high-level signal to the third input end of the main control unit, and the operational amplifier U11 still outputs a low-level signal; therefore, the difference of the level signals of the main control unit can judge whether the motor has overvoltage or undervoltage. When under-voltage or over-voltage exists, the protection main control unit can send a control instruction to the protection circuit.
The input end of the voltage detection circuit is the first input end of the optocoupler U10, the diode D1 in FIG. 4 plays a role in rectification, and the capacitor C4 and the capacitor C5 in FIG. 5 play a role in filtering, so that the alternating current output by the transformer T1 can be changed into direct current, and the motor running voltage detection is more convenient.
As shown in fig. 6, the embodiment further includes a temperature detection circuit, where the temperature detection circuit includes an operational amplifier U13, a thermistor RT, a resistor R10, a resistor R11, a resistor R3, a voltage regulator U15, a resistor RP1, an operational amplifier U14 and a resistor R12, where the non-inverting input terminal of the operational amplifier U13 is grounded, the inverting input terminal of the operational amplifier U13 is connected to the cathode of the voltage regulator U15 through the resistor R3, the anode of the voltage regulator U15 is grounded, the control electrode of the voltage regulator U15 is connected to the control terminal of the resistor RP1, the first terminal of the resistor RP1 is connected to a-5V power supply, the second terminal of the resistor RP1 is grounded, the output terminal of the operational amplifier U13 is connected to the inverting input terminal of the operational amplifier U13 through the thermistor RT, the non-inverting input terminal of the operational amplifier U14 is connected to the inverting input terminal of the operational amplifier U13 through the resistor R11, the output terminal of the operational amplifier U14 is connected to the inverting input terminal of the operational amplifier U14 through the resistor R12, and the output terminal of the operational amplifier U14 is connected to the fourth input terminal of the master control unit.
In the running process of the motor, if the winding temperature is too high, the aging of the motor can be accelerated, and if severe, the motor can be directly burnt out, so that the embodiment is also connected with a temperature detection circuit for detecting the winding temperature of the motor.
Specifically, the working principle of the temperature detection circuit is as follows: the thermistor RT is used for detecting the winding temperature when the motor operates, the thermistor RT is a negative temperature coefficient, the higher the temperature is, the smaller the resistance value is, the higher the temperature is, the resistance value is, the greater the resistance value is, the varistor RP1 and the voltage stabilizer U15 form a voltage stabilizing source, the operational amplifier U13, the thermistor RT, the resistor R3, the voltage stabilizer U15 and the varistor RP1 form a voltage stabilizing circuit, the thermistor RT is used as a feedback resistor of the operational amplifier U13, the operational amplifier U14 forms an amplifying circuit, the resistance value of the thermistor RT changes along with the change of the motor winding temperature, therefore, the voltage at two ends of the thermistor RT also changes, but the voltage change is smaller, the main control unit cannot directly and effectively identify the voltage, and therefore, the amplified electric signal is finally sent to the main control unit through the operational amplifier U14. And the main control unit judges the temperature value of the motor winding according to the output voltage of the operational amplifier U14.
As shown in fig. 7, a filter circuit is further disposed between the output end of the op-amp U14 and the fourth input end of the main control unit in this embodiment, the filter circuit includes a resistor R13, a capacitor C2, a resistor R14, an op-amp U16, a capacitor C3 and a resistor R15, the first end of the resistor R13 is connected to the output end of the op-amp U14, the second end of the resistor R13 is grounded through the capacitor C2, the second end of the resistor R13 is connected to the inverting input end of the op-amp U16 through the resistor R14, the non-inverting input end of the op-amp U16 is grounded, the output end of the op-amp U16 is connected to the inverting input end of the op-amp U16 through the capacitor C3, the output end of the op-amp U16 is connected to the second end of the resistor R13 through the resistor R15, and the output end of the op-amp U16 is connected to the fourth input end of the main control unit.
In the temperature detection process, high-frequency interference or noise interference exists in the circuit, and the accuracy of temperature detection can be seriously influenced by the interference signals, so that a filter circuit is arranged between the output end of the operational amplifier U14 and the fourth input end of the main control unit.
The resistor R13, the capacitor C2, the resistor R14, the op-amp U16, the capacitor C3 and the resistor R15 form a second-order low-pass filter for filtering high-frequency clutter and noise signals, and finally, the filtered electric signals are sent to the main control unit. When the temperature of the motor winding exceeds a set value, the main control unit sends a control instruction to the protection circuit, so that the motor stops running in time.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (6)
1. The motor fault detection circuit is characterized by comprising a voltage conversion circuit, an inverted phase detection circuit and a main control unit, wherein the voltage conversion circuit is used for outputting square wave signals with the same frequency as three-phase electricity, the input end of the inverted phase detection circuit is connected with the output end of the voltage conversion circuit, the output end of the inverted phase detection circuit is connected with the main control unit, the inverted phase detection circuit comprises an NAND gate U1, an NAND gate U2, an NAND gate U3, an NAND gate U4, an NAND gate U5, an NAND gate U6 and a trigger U7,
the first input end of the NAND gate U2 is connected with a 5V power supply, the second input end of the NAND gate U2 is connected with a signal generator, the third input end of the NAND gate U2 is connected with the output end of the NAND gate U4, the output end of the NAND gate U2 is connected with the first input end of the NAND gate U1,
the second input end of the NAND gate U1 is connected with a 5V power supply, the third input end of the NAND gate U1 is connected with the output end of the NAND gate U3, the output end of the NAND gate U1 is connected with the first input end of the NAND gate U3, the second input end of the NAND gate U3 is connected with the second input end of the NAND gate U2, the third input end of the NAND gate U3 is connected with the first output end of the voltage conversion circuit, the output end of the NAND gate U3 is connected with the second input end of the NAND gate U4, the third input end of the NAND gate U4 is connected with the first output end of the voltage conversion circuit,
the output end of the NAND gate U3 is connected with the first input end of the NAND gate U6, the output end of the NAND gate U4 is connected with the first input end of the NAND gate U5,
the second input end of the NAND gate U6 is connected with a 5V power supply, the third input end of the NAND gate U6 is connected with the output end of the NAND gate U5, the output end of the NAND gate U6 is connected with the input end of the trigger U7, the output end of the NAND gate U6 is connected with the second input end of the NAND gate U5, the third input end of the NAND gate U5 is connected with the second input end of the NAND gate U2,
the clock end of the trigger U7 is connected with the second output end of the voltage conversion circuit, the reset end of the trigger U7 is connected with the second input end of the NAND gate U2, the set end of the trigger U7 is connected with a 5V power supply, and the output end of the trigger U7 is connected with the first input end of the main control unit.
2. The motor fault detection circuit according to claim 1, further comprising a protection circuit, wherein the protection circuit comprises an optocoupler U17, a resistor R16, a triode Q1 and a relay K1, a first input end of the optocoupler U17 is connected with a 5V power supply, a second input end of the optocoupler U17 is connected with a first output end of the main control unit, a first output end of the optocoupler U17 is connected with a 12V power supply, a second output end of the optocoupler U17 is connected with a base electrode of the triode Q1 through the resistor R16, a collector electrode of the triode Q1 is connected with a first input end of the relay K1, a second input end of the relay K1 is connected with a 12V power supply, a normally closed end of the relay K1 is connected with a power supply system, a common end of the relay K1 is connected with a motor, and an emitter electrode of the triode Q1 is grounded.
3. The motor fault detection circuit according to claim 1, wherein the voltage conversion circuit comprises two branches with the same circuit structure, any one branch comprises a transformer T1, a resistor R1, an optocoupler U10, a not gate U8 and a not gate U9, a first input end of the transformer T1 is connected with a phase a power supply, a second input end of the transformer T1 is connected with a zero line, a first output end of the transformer T1 is connected with a first input end of the optocoupler U10 through the resistor R1, a second output end of the optocoupler U10 is connected with a second output end of the transformer T1, a first output end of the optocoupler U10 is connected with a 5V power supply, a second output end of the optocoupler U10 is connected with an input end of the not gate U8, an output end of the not gate U8 is connected with an input end of the not gate U9, and an output end of the not gate U9 is connected with a third input end of the not gate U3 and the not gate U4.
4. The motor fault detection circuit of claim 3, further comprising a voltage detection circuit comprising a resistor R4, a resistor R7, an op-amp U11, an op-amp U12, a resistor R8, a resistor R9, a diode D2, and a diode D3,
the in-phase input end of the operational amplifier U11 is connected with the first input end of the optocoupler U10 through the resistor R4, the anti-phase input end of the operational amplifier U11 is connected with the first end of the resistor R9, the first end of the resistor R9 is connected with a 5V power supply through the resistor R8, the second end of the resistor R9 is grounded, the output end of the operational amplifier U11 is connected with the anode of the diode D2, the cathode of the diode D2 is connected with the second input end of the main control unit, the anti-phase input end of the operational amplifier U12 is connected with the first input end of the optocoupler U10 through the resistor R7, the in-phase input end of the operational amplifier U12 is connected with the first end of the resistor R9, the output end of the operational amplifier U12 is connected with the anode of the diode D3, and the cathode of the diode D3 is connected with the third input end of the main control unit.
5. The motor fault detection circuit according to claim 1, further comprising a temperature detection circuit, wherein the temperature detection circuit comprises an operational amplifier U13, a thermistor RT, a resistor R10, a resistor R11, a resistor R3, a voltage stabilizer U15, a resistor RP1, an operational amplifier U14 and a resistor R12, wherein a non-inverting input terminal of the operational amplifier U13 is grounded, an inverting input terminal of the operational amplifier U13 is connected to a cathode of the voltage stabilizer U15 through the resistor R3, an anode of the voltage stabilizer U15 is grounded, a control terminal of the voltage stabilizer U15 is connected to a control terminal of the resistor RP1, a first terminal of the resistor RP1 is connected to a-5V power supply, a second terminal of the resistor RP1 is grounded, an output terminal of the operational amplifier U13 is connected to an inverting input terminal of the operational amplifier U13 through the resistor R10, an input terminal of the operational amplifier U14 is connected to an inverting input terminal of the operational amplifier U14 through the resistor R11, and an output terminal of the operational amplifier U14 is connected to an inverting input terminal of the operational amplifier U14 through the inverting terminal of the resistor R14.
6. The motor fault detection circuit according to claim 5, wherein a filter circuit is further disposed between the output end of the operational amplifier U14 and the fourth input end of the main control unit, the filter circuit includes a resistor R13, a capacitor C2, a resistor R14, an operational amplifier U16, a capacitor C3 and a resistor R15, the first end of the resistor R13 is connected to the output end of the operational amplifier U14, the second end of the resistor R13 is grounded through the capacitor C2, the second end of the resistor R13 is connected to the inverting input end of the operational amplifier U16 through the resistor R14, the non-inverting input end of the operational amplifier U16 is grounded, the output end of the operational amplifier U16 is connected to the inverting input end of the operational amplifier U16 through the capacitor C3, the output end of the operational amplifier U16 is connected to the second end of the resistor R13 through the resistor R15, and the output end of the operational amplifier U16 is connected to the fourth input end of the main control unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311019782.9A CN117031273A (en) | 2023-08-14 | 2023-08-14 | Motor fault detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311019782.9A CN117031273A (en) | 2023-08-14 | 2023-08-14 | Motor fault detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117031273A true CN117031273A (en) | 2023-11-10 |
Family
ID=88622316
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311019782.9A Withdrawn CN117031273A (en) | 2023-08-14 | 2023-08-14 | Motor fault detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117031273A (en) |
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2023
- 2023-08-14 CN CN202311019782.9A patent/CN117031273A/en not_active Withdrawn
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