CN114678834A - Overload protection circuit and method for three-phase asynchronous motor - Google Patents

Overload protection circuit and method for three-phase asynchronous motor Download PDF

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Publication number
CN114678834A
CN114678834A CN202210584267.4A CN202210584267A CN114678834A CN 114678834 A CN114678834 A CN 114678834A CN 202210584267 A CN202210584267 A CN 202210584267A CN 114678834 A CN114678834 A CN 114678834A
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circuit
phase
voltage
current
driving
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CN202210584267.4A
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CN114678834B (en
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陈思敏
刘杰
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Shenzhen Xiner Semiconductor Technology Co Ltd
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Shenzhen Xiner Semiconductor Technology Co Ltd
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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
    • 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
    • H02H3/083—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for three-phase systems
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
    • H02H3/093—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current with timing means
    • 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
    • H02H7/0833—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 for electric motors with control arrangements
    • H02H7/0838—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 for electric motors with control arrangements with H-bridge circuit
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • H02M1/092—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices the control signals being transmitted optically
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • 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
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P80/00—Climate change mitigation technologies for sector-wide applications
    • Y02P80/10—Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

Abstract

The invention relates to an overload protection circuit and method for a three-phase asynchronous motor, wherein the method comprises the following steps: any phase current of the three-phase asynchronous motor is collected through the control circuit, and whether the current phase current is larger than an overload current threshold value is judged at preset time intervals through the time of a timer; if the value is larger than the preset value, adding 1 to the overload protection counting value; if the value is less than the preset value, subtracting 1 from the overload protection count value; monitoring whether the overload protection count value exceeds a set count threshold value in real time; if the number of the overload protection counter values exceeds the preset value, a stop instruction is sent to drive the three-phase asynchronous motor to stop, and if the number of the overload protection counter values does not exceed the preset value, the overload protection counter values are continuously monitored. The overload protection method for the three-phase asynchronous motor only needs to acquire one phase current and can realize the overload protection of the three-phase asynchronous motor by simple judgment through the timer which is basically arranged outside the single chip microcomputer, complex operation and external circuits are not needed, the method is easy to realize, low in cost and strong in transportability, and the overload protection method can be effectively applied to the overload protection of the three-phase asynchronous motor.

Description

Overload protection circuit and method for three-phase asynchronous motor
Technical Field
The invention relates to the technical field of alternating current servo drive protection, in particular to an overload protection circuit and method for a three-phase asynchronous motor.
Background
Asynchronous motors are mainly used as motors, dragging various production machines, such as: fans, pumps, compressors, machine tools, light and mining machinery, threshing and crushing machines in agricultural production, processing machinery in agricultural and sideline products and the like. Simple structure, easy manufacture, low price, reliable operation, firmness, durability, higher operation efficiency and applicable working characteristics.
In order to protect the motor from overload under abnormal conditions, the motor is damaged by overlarge current. Overload protection is important for three-phase asynchronous machines. In the prior overload protection of the three-phase asynchronous motor, one direction is to add an overload protection element thermal relay and detect the overload heating of the motor through a thermal relay heating element so as to disconnect the input of the motor. And in the other direction, the effective current of the motor is calculated by acquiring the phase current of the motor and performing complex calculation of model conversion, and the overload protection is realized through the calculated current value.
In the prior art, the effective value of the current is calculated by collecting two phases of current and calculating the square of the current and the square of the current and other complex operations, so that whether the motor is overloaded or not is judged. However, the calculation method for acquiring phase current needs complex mathematical operation on the current, and both the operation and the accurate acquisition have high hardware requirements on the controller, thereby increasing the cost of the controller and the complexity of software.
Disclosure of Invention
In view of this, it is necessary to provide an overload protection circuit and method for a three-phase asynchronous motor, which detect an overload current of the three-phase asynchronous motor by collecting a phase current of any phase and determining the magnitude of the phase current at regular intervals, so as to implement overload protection shutdown of the three-phase asynchronous motor.
In order to achieve the above object, the present invention provides an overload protection circuit for a three-phase asynchronous motor, comprising:
the power supply circuit, the drive circuit, the control circuit, the inverter circuit and the current amplification circuit; the power supply circuit is electrically connected with the drive circuit, the control circuit, the inverter circuit and the current amplification circuit, the drive circuit is also electrically connected with the control circuit and the inverter circuit, the control circuit is also electrically connected with the current amplification circuit, and the inverter circuit is electrically connected with the current amplification circuit;
the power supply circuit is used for respectively providing different voltages for the driving circuit, the control circuit, the inverter circuit and the current amplification circuit to supply power;
the driving circuit is used for amplifying the driving voltage and then outputting a driving signal to the inverter circuit;
the inverter circuit is used for inverting the driving signal to obtain three-phase inverter current and outputting the three-phase inverter current to the three-phase asynchronous motor to work;
the current amplification circuit is used for amplifying any single-phase current in the three-phase inverter current to obtain an amplified current signal and outputting the amplified current signal to the control circuit;
the control circuit is used for carrying out timing judgment according to the single-phase current corresponding to the amplified current signal and carrying out power-off protection on the three-phase asynchronous motor based on a judgment result.
Preferably, the power supply circuit comprises a voltage division circuit, a voltage regulation circuit and an inductive coupling circuit;
the voltage division circuit is used for dividing the voltage of the accessed mains supply;
the voltage regulating circuit is used for regulating the divided voltage;
the inductive coupling circuit is used for carrying out inductive coupling processing according to the regulated voltage so as to provide different voltages for the driving circuit, the control circuit, the inverter circuit and the current amplifying circuit.
Preferably, the voltage dividing circuit includes resistors R19, R20, R21, R23 and R25, capacitors C3, C4, and diodes D9 and D10, wherein the resistors R19, R20, R21, R23 and R25 are sequentially connected in series, one end of the capacitor C3 is connected to the common terminal of the resistors R21 and R23, the other end of the capacitor C3 is grounded, two ends of the capacitor C4 are connected in parallel to two ends of the resistors R23 and R25, and the diodes D9 and D10 are reversely connected to the common terminals of the resistors C4, R23 and R25;
the voltage regulating circuit comprises a voltage regulating chip U7, resistors R30, R32, R36, R42 and R45, capacitors C21, C22, C33, C37, C38 and a diode D14, wherein four DRAIN ends of the U7 are connected with the anode of the D10, the VDD end of the U7 is connected into the R30 and D14 which are connected in series and the C21 and C22 which are connected in parallel, the FB end of the U7 is connected into the R32 and R36 which are connected in series and the C33 and R42 which are connected in parallel, and the COMP end of the U7 is connected into the R45, C37 and C38 which are connected in series in parallel.
The inductive coupling circuit comprises an inductive coupling coil T1, and the inductive coupling coil T1 comprises a first coupling main coil, a second coupling main coil, a third coupling main coil, a fourth coupling main coil, a first coupling auxiliary coil, a second coupling auxiliary coil and a third coupling auxiliary coil;
two ends of the coil of the first coupling main coil are respectively connected to a common end of R21 and C3 and a positive end of D10, and are used for connecting a first divided voltage of a mains supply, the first coupling auxiliary coil is coupled with the first coupling main coil to provide a positive voltage and a negative voltage for driving a W phase in a driving circuit, and a negative voltage output by the W phase in an inverter circuit, the second coupling auxiliary coil is coupled with the first coupling main coil to provide a positive voltage and a negative voltage for driving a V phase in the driving circuit, and a negative voltage output by the V phase in the inverter circuit, the third coupling auxiliary coil is coupled with the first coupling main coil to provide a positive voltage and a negative voltage for driving a U phase in the driving circuit, and a negative voltage output by the U phase in the inverter circuit;
the second coupling main coil and the second coupling auxiliary coil are coupled to provide three-phase public voltage for the driving circuit, the third coupling main coil and the second coupling auxiliary coil are coupled to provide voltage for the current amplifying circuit and the control circuit, and the fourth coupling main coil and the third coupling auxiliary coil are coupled to provide voltage for the display circuit.
Preferably, the output end of the first coupling secondary coil includes three ends, wherein a first end is connected to a diode D7 and then outputs a positive voltage for driving a W phase in the driving circuit, a second end directly outputs a negative voltage for driving the W phase in the inverter circuit, a third end is connected to a diode D8 and then outputs a negative voltage for driving the W phase in the driving circuit, capacitors C1 and C2 are connected in parallel between the first end and the second end, and capacitors C5 and C6 are connected in parallel between the second end and the third end;
the output end of the second coupling auxiliary coil also comprises three ends, wherein a first end is connected to a diode D11 and then outputs a positive voltage for driving a V phase in the driving circuit, a second end directly outputs a negative voltage for outputting the V phase in the inverter circuit, a third end is connected to a diode D15 and then outputs a negative voltage for driving the V phase in the driving circuit, capacitors C13 and C14 are connected between the first end and the second end in parallel, and capacitors C19 and C20 are connected between the second end and the third end in parallel;
the output end of the third coupling auxiliary coil also comprises three ends, wherein a first end is connected to a diode D17 and then outputs a positive voltage for driving a U phase in the driving circuit, a second end directly outputs a negative voltage for outputting the U phase in the inverter circuit, a third end is connected to a diode D19 and then outputs a negative voltage for driving the U phase in the driving circuit, capacitors C27 and C28 are connected between the first end and the second end in parallel, and capacitors C31 and C32 are connected between the second end and the third end in parallel;
the output end of the second coupling main coil also comprises three ends, wherein a first end is connected to a diode D12 and then outputs three-phase public positive voltage, a second end is grounded, a third end is connected to a diode D13 and then outputs three-phase public negative voltage, capacitors C10, C11 and C12 are connected between the first end and the second end in parallel, and capacitors C15, C16 and C17 are connected between the second end and the third end in parallel;
the output end of the third coupling main coil comprises two ends, wherein the first end is connected with a diode D16 and then outputs forward voltage to a voltage reduction chip U8 after passing through a resistor R44, the second end is grounded, and the voltage reduction chip U8 outputs voltage to the power ends of the current amplification circuit and the control circuit after reducing voltage;
the output end of the fourth coupling main coil comprises two ends, wherein the first end is connected to the diode D18 and outputs forward voltage to the voltage stabilizing diode U9 after passing through the resistor R43, the second end is grounded, and the voltage reducing chip U9 outputs voltage to the power supply end of the display circuit after stabilizing voltage.
Preferably, the driving circuit comprises six optical coupling signal amplifiers and six current regulating circuits, and the six optical coupling signal amplifiers and the six current regulating circuits are connected in one-to-one correspondence;
the VCC end of the first optocoupler signal amplifier U1 is connected with the positive voltage of the U phase, the GND end is connected with the negative voltage of the U phase, the ANODE end is connected with an UP input signal, and the Vout end inputs an UP driving signal through the first current regulating circuit;
the VCC end of the second optocoupler signal amplifier U2 is connected to the positive voltage of the W phase, the GND end is connected to the negative voltage of the W phase, the ANODE end is connected to a WP input signal, and the Vout end is connected to a WP driving signal through a second current regulating circuit;
the VCC end of the third optocoupler signal amplifier U3 is connected to the positive voltage of the V phase, the GND end is connected to the negative voltage of the V phase, the ANODE end is connected to the VP input signal, and the Vout end is connected to the VP driving signal through the third current regulating circuit;
the VCC end of the fourth optocoupler signal amplifier U4 is connected to the three-phase common positive voltage, the GND end is connected to the three-phase common negative voltage, the ANODE end is connected to the UN input signal, and the Vout end is connected to the UN driving signal through the fourth current regulating circuit;
a VCC end of the fifth optocoupler signal amplifier U5 is connected to the three-phase common positive voltage, a GND end of the fifth optocoupler signal amplifier U5 is connected to the three-phase common negative voltage, an ANODE end of the fifth optocoupler signal amplifier U5 is connected to the WN input signal, and a Vout end of the fifth optocoupler signal amplifier U5 is connected to the WN driving signal through the fifth current regulating circuit;
the VCC end of the sixth optocoupler signal amplifier U6 is connected to the three-phase public positive voltage, the GND end is connected to the three-phase public negative voltage, the ANODE end is connected to the VN input signal, and the Vout end is connected to the VN driving signal through the sixth current regulating circuit.
Preferably, the inverter circuit includes six IGBT circuits;
the first IGBT circuit is connected with the UP driving signal, the second IGBT circuit is connected with the UN driving signal, and the first IGBT circuit and the second IGBT circuit are used for carrying out AC-DC inversion according to the UN driving signal and the UN driving signal to obtain U-phase output current and outputting the U-phase output current to a U-phase input end of the three-phase asynchronous motor;
the third IGBT circuit is connected with the VP driving signal, the fourth IGBT circuit is connected with the VN driving signal, and the third IGBT circuit and the fourth IGBT circuit are used for performing AC-DC inversion according to the VN driving signal and the VN driving signal to obtain a V-phase output current and outputting the V-phase output current to a V-phase input end of the three-phase asynchronous motor;
the fifth IGBT circuit is connected with the WP driving signal, the sixth IGBT circuit is connected with the WN driving signal, and the fifth IGBT circuit and the sixth IGBT circuit are used for carrying out alternating-direct inversion according to the VN driving signal and the WN driving signal to obtain W-phase output current and outputting the W-phase output current to the W-phase input end of the three-phase asynchronous motor.
Preferably, the current amplifying circuit comprises a current amplifier U20A, resistors R86, R90, R93, R96, R99 and R102, and capacitors C43 and C49;
the power supply end of the current amplifier U20A is connected to the output voltage of the third main coil after being stepped down by the step-down chip U8, the non-inverting input end is connected to R96, R99, R102 and C49 in parallel, the inverting input end is connected to R90, R86 is connected to the inverting input end and the output end at the same time, and the input end is connected to R93 and C43 in series and then outputs an amplified current signal to the control circuit.
Preferably, the control circuit includes a main control chip U12, the VDD terminal of the U12 is connected to the output voltage of the third main coil after being stepped down by the step-down chip U8, the pins P10, P11, P12, P13, P14 and P15 output the WN input signal, VN input signal, WP input signal, VP input signal, UN input signal and UP input signal, respectively, and the pin P20 is connected to the amplified current signal.
In order to achieve the above object, the present invention further provides an overload protection method for an overload protection circuit of a three-phase asynchronous motor, the method comprising:
any phase current of the three-phase asynchronous motor is collected through the control circuit, and whether the current phase current is larger than an overload current threshold value is judged at preset time intervals through the time of a timer;
if the value is larger than the preset value, adding 1 to the overload protection counting value;
if not, subtracting 1 from the overload protection count value;
monitoring whether the overload protection count value exceeds a set count threshold value in real time;
if the number of the overload protection counter values exceeds the preset value, a stop instruction is sent to drive the three-phase asynchronous motor to stop, and if the number of the overload protection counter values does not exceed the preset value, the overload protection counter values are continuously monitored.
Preferably, the method further comprises:
and monitoring the timing duration of the timer in real time, and if the timing duration of the timer exceeds the preset duration, outputting a shutdown instruction to drive the three-phase asynchronous motor to be shut down.
The invention has the beneficial effects that: the overload protection method for the three-phase asynchronous motor only needs to acquire one phase current and can realize the overload protection of the three-phase asynchronous motor by simple judgment through the timer which is basically arranged outside the single chip microcomputer, complex operation and external circuits are not needed, the method is easy to realize, low in cost and strong in transportability, and the overload protection method can be effectively applied to the overload protection of the three-phase asynchronous motor.
Drawings
Fig. 1 is a circuit framework diagram of an embodiment of an overload protection circuit for a three-phase asynchronous motor provided by the invention;
FIG. 2 is a schematic circuit diagram of an embodiment of a power circuit provided in the present invention;
FIG. 3 is a schematic circuit diagram of an embodiment of a driving circuit provided in the present invention;
FIG. 4 is a schematic circuit diagram of an embodiment of a control circuit provided in the present invention;
FIG. 5 is a schematic circuit diagram of an embodiment of an inverter circuit according to the present invention;
FIG. 6 is a schematic circuit diagram of an embodiment of a current amplifying circuit according to the present invention;
fig. 7 is a schematic flow chart of an embodiment of an overload protection method for a three-phase asynchronous motor according to the present invention.
Detailed Description
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.
As shown in fig. 1, an embodiment of the present invention provides an overload protection circuit for a three-phase asynchronous motor, including:
a power supply circuit 10, a drive circuit 20, a control circuit 30, an inverter circuit 40, and a current amplifier circuit 50; the power circuit 10 is electrically connected with the driving circuit 20, the control circuit 30, the inverter circuit 40 and the current amplifying circuit 50, the driving circuit 20 is also electrically connected with the control circuit 30 and the inverter circuit 40, the control circuit 30 is also electrically connected with the current amplifying circuit 50, and the inverter circuit 40 is electrically connected with the current amplifying circuit 50;
the power circuit 10 is configured to provide different voltages to the driving circuit 20, the control circuit 30, the inverter circuit 40, and the current amplifying circuit 50 for power supply;
the driving circuit 20 is configured to amplify the driving voltage and output a driving signal to the inverter circuit 40;
the inverter circuit 40 is used for inverting the driving signal to obtain a three-phase inverter current and outputting the three-phase inverter current to the three-phase asynchronous motor to work;
the current amplifying circuit 50 is configured to amplify any single-phase current of the three-phase inverter current to obtain an amplified current signal, and output the amplified current signal to the control circuit 30;
the control circuit 30 is configured to perform timing judgment according to the single-phase current corresponding to the amplified current signal, and perform power-off protection on the three-phase asynchronous motor based on a judgment result.
In a preferred embodiment, the power circuit 10 includes a voltage divider circuit, a voltage regulator circuit, and an inductive coupling circuit;
the voltage division circuit is used for dividing the voltage of the accessed mains supply;
the voltage regulating circuit is used for regulating the divided voltage;
the inductive coupling circuit is used for carrying out inductive coupling processing according to the regulated voltage so as to provide different voltages for the driving circuit, the control circuit, the inverter circuit and the current amplifying circuit.
For explaining the overload protection circuit of the three-phase asynchronous motor provided by the embodiment of the invention in detail, the detailed circuit principle is described with reference to fig. 2-6, wherein fig. 2 is a circuit schematic diagram of an embodiment of the power supply circuit provided by the invention; FIG. 3 is a schematic circuit diagram of an embodiment of a driving circuit according to the present invention; FIG. 4 is a schematic circuit diagram of an embodiment of a control circuit provided in the present invention; FIG. 5 is a schematic circuit diagram of an embodiment of an inverter circuit according to the present invention; fig. 6 is a schematic circuit diagram of a current amplifying circuit according to an embodiment of the present invention.
In this embodiment, the voltage divider circuit includes resistors R19, R20, R21, R23, and R25, capacitors C3, C4, and diodes D9 and D10, wherein the resistors R19, R20, R21, R23, and R25 are sequentially connected in series, one end of the capacitor C3 is connected to a common terminal of the resistors R21 and R23, the other end of the capacitor C3 is grounded, two ends of the capacitor C4 are connected in parallel to two ends of the resistors R23 and R25, and the diodes D9 and D10 are reversely connected to common terminals of the resistors C4, R23, and R25.
It can be understood that by setting the resistances of the resistors R19, R20, R21, R23, and R25, when the power supply circuit receives the mains voltage (BUS +), the voltage can be reasonably distributed, for example, after R19, R20, and R21 are used to share most of the voltage, the voltage input to the voltage regulating circuit and the inductive coupling circuit is about 15V.
The voltage regulating circuit comprises a voltage regulating chip U7, resistors R30, R32, R36, R42 and R45, capacitors C21, C22, C33, C37, C38 and a diode D14, wherein four DRAIN ends of the U7 are connected with the anode of the D10, the VDD end of the U7 is connected into the R30 and D14 which are connected in series and the C21 and C22 which are connected in parallel, the FB end of the U7 is connected into the R32 and R36 which are connected in series and the C33 and R42 which are connected in parallel, and the COMP end of the U7 is connected into the R45, C37 and C38 which are connected in series in parallel.
It should be noted that the model of the voltage regulating chip U7 is VIPER26K, and its main function is power supply voltage distribution assistance, a power supply terminal VDD of the voltage regulating chip may be connected to a voltage after inductive coupling, and then the voltage is fed back and regulated by four DRAIN terminals, and finally the voltage of the positive electrode of the main coil reaches a stable preset value, such as 15V, and resistors and capacitors connected to other ports can protect the chip and the regulating circuit structure.
In this embodiment, referring to fig. 2, the inductive coupling circuit includes an inductive coupling coil T1, and the inductive coupling coil T1 includes a first coupling main coil, a second coupling main coil, a third coupling main coil, a fourth coupling main coil, a first coupling sub-coil, a second coupling sub-coil, and a third coupling sub-coil.
Two ends (namely, two ends 1 and 3 in fig. 2) of a coil of the first coupling main coil are respectively connected to a common end of R21 and C3 and a positive end of D10, and are used for connecting a first divided voltage of a mains supply, the first coupling auxiliary coil is coupled with the first coupling main coil to provide a positive voltage and a negative voltage for driving a W phase in a driving circuit, and a negative voltage for outputting the W phase in an inverter circuit, the second coupling auxiliary coil is coupled with the first coupling main coil to provide a positive voltage and a negative voltage for driving a V phase in the driving circuit, and a negative voltage for outputting the V phase in the inverter circuit, the third coupling auxiliary coil is coupled with the first coupling main coil to provide a positive voltage and a negative voltage for driving a U phase in the driving circuit, and a negative voltage for outputting the U phase in the inverter circuit;
the second coupling main coil and the second coupling auxiliary coil are coupled to provide three-phase public voltage for the driving circuit, the third coupling main coil and the second coupling auxiliary coil are coupled to provide voltage for the current amplifying circuit and the control circuit, and the fourth coupling main coil and the third coupling auxiliary coil are coupled to provide voltage for the display circuit.
In this embodiment, with reference to fig. 2, the output end of the first coupling secondary winding includes three ends (i.e., 24, 25, and 26 in fig. 2), wherein a first end is connected to a diode D7 and then outputs a positive voltage (e.g., HW signal of +15V in fig. 2) for driving the W phase in the driving circuit, a second end directly outputs a negative voltage (e.g., HW signal of-7V in fig. 2) for driving the W phase in the inverter circuit, a third end is connected to a diode D8 and then outputs a negative voltage (e.g., GND signal in fig. 2) for driving the W phase in the driving circuit, capacitors C1 and C2 are connected in parallel between the first end and the second end, and capacitors C5 and C6 are connected in parallel between the second end and the third end;
the output end of the second coupling secondary coil also comprises three ends (namely 19, 20 and 21 in fig. 2), wherein a first end is connected to a diode D11 and then outputs a positive electrode voltage (such as a HV signal of +15V in fig. 2) for driving a V phase in the driving circuit, a second end directly outputs a negative electrode voltage (such as a HV signal of-7V in fig. 2) for driving the V phase in the inverter circuit, a third end is connected to a diode D15 and then outputs a negative electrode voltage (such as a HV GND signal in fig. 2) for driving the V phase in the driving circuit, capacitors C13 and C14 are connected between the first end and the second end in parallel, and capacitors C19 and C20 are connected between the second end and the third end in parallel;
the output end of the third coupled secondary winding also includes three ends (i.e. 14, 15, 16 in fig. 2), wherein a first end is connected to a diode D17 and then outputs a positive voltage (e.g. an HU signal of +15V in fig. 2) for driving the U-phase in the driving circuit, a second end directly outputs a negative voltage (e.g. an HU signal of-7V in fig. 2) for driving the U-phase in the inverter circuit, a third end is connected to a diode D19 and then outputs a negative voltage (e.g. an HU GND signal in fig. 2) for driving the U-phase in the driving circuit, capacitors C27 and C28 are connected in parallel between the first end and the second end, and capacitors C31 and C32 are connected in parallel between the second end and the third end;
the output end of the second coupled main coil also includes three ends (i.e. 5, 6, 7 in fig. 2), wherein the first end is connected to the diode D12 and then outputs a common positive voltage (i.e. +15V in fig. 2) of the three phases, the second end is grounded, the third end is connected to the diode D13 and then outputs a common negative voltage (i.e. — 7V in fig. 2), capacitors C10, C11 and C12 are connected in parallel between the first end and the second end, and capacitors C15, C16 and C17 are connected in parallel between the second end and the third end;
the output end of the third coupling main coil comprises two ends (i.e. 8 and 9 in fig. 2), wherein the first end is connected to the diode D16 and then outputs a forward voltage (i.e. +12V in fig. 2) to the buck chip U8 through the resistor R44, the second end is grounded, the buck chip U8 steps down and then outputs a voltage (i.e. +5V in fig. 2) to the power supply ends of the current amplifying circuit and the control circuit, wherein the model of the buck chip U8 is 7805, the input end of the buck chip U8 is further connected to the capacitor C34 connected in parallel with the resistor, and the output end is connected to the capacitors CE1 and C35 connected in parallel;
the output end of the fourth coupled main coil comprises two ends (i.e. 12 and 13 in fig. 2), wherein a first end is connected to a diode D18 and then outputs a forward voltage (i.e. +14V in fig. 2) to a zener diode U9 through a resistor R43, a second end is grounded, the buck chip U9 performs voltage stabilization and then outputs a voltage (i.e. +10V in fig. 2) to a power supply end of a display circuit (not shown in the figure), wherein the zener diode U9 performs voltage stabilization regulation through R46, R47 and R49, and the model of the zener diode U9 is TL 431.
In this embodiment, referring to fig. 3, the driving circuit includes six optical coupling signal amplifiers and six current adjusting circuits, and the six optical coupling signal amplifiers and the six current adjusting circuits are connected in a one-to-one correspondence manner;
the VCC end of the first optical coupler signal amplifier U1 is connected to the positive voltage of the U phase (namely an HU signal of + 15V), the GND end is connected to the negative voltage of the U phase (namely an HU signal of-7V), the ANODE end is connected to an UP input signal, and the Vout end is connected to an UP driving signal (namely UP _ OUT) through a first current regulating circuit, wherein the first current regulating circuit is a circuit formed by connecting a resistor R10 and a diode D1 in series and then connecting the resistor R4 in parallel;
the VCC end of the second optical coupler signal amplifier U2 is connected to the positive voltage of the W phase (namely HW signal of + 15V), the GND end is connected to the negative voltage of the W phase (namely HW signal of-7V), the ANODE end is connected to the WP input signal, and the Vout end is connected to the WP driving signal (namely WP _ OUT) through the second current regulating circuit, wherein the first current regulating circuit is a circuit formed by connecting a resistor R11 and a diode D2 in series and then connecting the resistor R8 in parallel;
the VCC end of the third optical coupling signal amplifier U3 is connected to the positive voltage of the V phase (namely, HV signal of + 15V), the GND end is connected to the negative voltage of the V phase (namely, HV signal of-7V), the ANODE end is connected to the VP input signal, and the Vout end is connected to the VP drive signal (namely, VP _ OUT) through the third current regulating circuit, wherein the first current regulating circuit is a circuit formed by connecting a resistor R12 and a diode D3 in series and then connecting the resistor R9 in parallel;
the VCC end of the fourth optical coupling signal amplifier U4 is connected to the three-phase common positive voltage (namely +15V signal), the GND end is connected to the three-phase common negative voltage (namely-7V signal), the ANODE end is connected to the UN input signal, and the Vout end is connected to the UN driving signal (namely UN _ OUT) through a fourth current regulating circuit, wherein the first current regulating circuit is a circuit formed by connecting a resistor R16 and a diode D4 in series and then connecting the resistor R13 in parallel;
the VCC end of the fifth optical coupling signal amplifier U5 is connected to the three-phase common positive voltage (namely +15V signal), the GND end is connected to the three-phase common negative voltage (namely-7V signal), the ANODE end is connected to the WN input signal, and the Vout end is connected to the WN driving signal (namely WN _ OUT) through a fifth current regulating circuit, wherein the first current regulating circuit is a circuit formed by connecting a resistor R17 and a diode D5 in series and then connecting the resistor R14 in parallel;
the VCC end of the sixth optical coupling signal amplifier U6 is connected to the three-phase common positive voltage (namely +15V signal), the GND end is connected to the three-phase common negative voltage (namely-7V signal), the ANODE end is connected to the VN input signal, and the Vout end is connected to the VN driving signal (namely VN _ OUT) through a sixth current regulating circuit, wherein the first current regulating circuit is a circuit formed by connecting a resistor R18 and a diode D6 in series and then connecting the resistor R15 in parallel.
In this embodiment, referring to fig. 5, the inverter circuit includes six IGBT circuits;
the first IGBT circuit is connected with the UP driving signal (namely UP _ OUT), the second IGBT circuit is connected with the UN driving signal (namely UN _ OUT), and the first IGBT circuit and the second IGBT circuit are used for carrying OUT AC-DC inversion according to the UN driving signal and the UN driving signal to obtain U-phase output current (namely IU) and outputting the U-phase output current to a U-phase input end of the three-phase asynchronous motor;
the third IGBT circuit is connected with the VP drive signal (namely VP _ OUT), the fourth IGBT circuit is connected with the VN drive signal (namely VN _ OUT), and the third IGBT circuit and the fourth IGBT circuit are used for performing alternating-direct inversion according to the VN drive signal and the VN drive signal to obtain a V-phase output current (namely IV) and outputting the V-phase output current to a V-phase input end of the three-phase asynchronous motor;
the fifth IGBT circuit is connected to the WP driving signal (WP _ OUT), the sixth IGBT circuit is connected to the WN driving signal (WN _ OUT), and the fifth IGBT circuit and the sixth IGBT circuit are used for performing alternating-direct inversion according to the VN driving signal and the WN driving signal to obtain W-phase output current (IW) and outputting the W-phase output current to the W-phase input end of the three-phase asynchronous motor.
It is understood that a three-phase asynchronous motor operates under the drive of three-phase currents (IU, IV and IW).
In this embodiment, referring to fig. 6, the current amplifying circuit includes a current amplifier U20A, resistors R86, R90, R93, R96, R99, and R102, and capacitors C43 and C49;
the power supply end of the current amplifier U20A is connected to the output voltage (namely + 5V) of the third main coil after being stepped down by the step-down chip U8, the non-inverting input end is connected to R96, R99, R102 and C49 in parallel, the inverting input end is connected to R90, R86 is connected to the inverting input end and the output end at the same time, and the input end is connected to the series-connected R93 and C43 to output an amplified current signal to the control circuit.
It can be understood that the current amplification circuit can amplify three-phase currents (IU, IV and IW) in the inverter circuit, so that the control circuit can perform subsequent control according to the current magnitude.
In this embodiment, referring to fig. 4, the control circuit includes a main control chip U12, the VDD terminal of the U12 is connected to the output voltage (i.e., + 5V) of the third main coil stepped down by the step-down chip U8, pins P10, P11, P12, P13, P14, and P15 output the WN input signal, VN input signal, WP input signal, VP input signal, UN input signal, and UP input signal, respectively, and pin P20 is connected to the amplified current signal, where the main control chip U12 is R5F104 BD.
It should be noted that when the main control chip detects a current value and performs preset time to judge that the current value exceeds time under a preset count value, the driving is cut off by on-off of a WN input signal, a VN input signal, a WP input signal, a VP input signal, a UN input signal and a UP input signal, so that the three-phase asynchronous motor is stopped.
In order to achieve the above object, the present invention further provides an overload protection method for an overload protection circuit of a three-phase asynchronous motor, referring to fig. 7, the method includes:
step S701, any phase current (such as phase current IU) of the three-phase asynchronous motor is collected through the control circuit;
step S702, determining, by a timer, every preset time (e.g. 50ms, which may be referred to as t 1) whether the current phase current is greater than the overload current threshold, if so, going to step S703, and if not, going to step S704;
step S703, adding 1 to the overload protection counting value;
step S704, subtracting 1 from the overload protection count value;
step S705, monitoring whether the overload protection count value exceeds a set count threshold value in real time, if so, executing step S706, and if not, continuing to monitor the overload protection count value;
and step S706, sending a stop instruction to drive the three-phase asynchronous motor to stop.
In other embodiments of the present invention, the method further comprises:
and monitoring the timing duration of the timer (which can be called as t2) in real time, and if the timing duration of the timer exceeds a preset duration, outputting a stop instruction to drive the three-phase asynchronous motor to stop.
In a specific embodiment, for example, t1 × 50 is set to be the value of t2, that is, the change of the detected current value in almost 50 timing periods, and of course, the specific value of t2 can be freely set according to the actual application.
In conclusion, the overload protection method and the overload protection device have the advantages that only one phase current needs to be acquired, simple judgment is carried out through the basic external timer of the single chip microcomputer, the overload protection of the three-phase asynchronous motor can be realized, complex operation and external circuits are not needed, the realization is easy, the cost is low, the transportability is strong, and the overload protection method and the overload protection device can be effectively applied to the overload protection of the three-phase asynchronous motor.
In summary, the preferred embodiments of the present invention are described, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention shall be covered by the scope of the present invention.

Claims (10)

1. An overload protection circuit for a three-phase asynchronous motor, comprising: the power supply circuit, the drive circuit, the control circuit, the inverter circuit and the current amplification circuit; the power supply circuit is electrically connected with the drive circuit, the control circuit, the inverter circuit and the current amplification circuit, the drive circuit is also electrically connected with the control circuit and the inverter circuit, the control circuit is also electrically connected with the current amplification circuit, and the inverter circuit is electrically connected with the current amplification circuit;
the power supply circuit is used for respectively providing different voltages for the driving circuit, the control circuit, the inverter circuit and the current amplification circuit to supply power;
the driving circuit is used for amplifying the driving voltage and then outputting a driving signal to the inverter circuit;
the inverter circuit is used for inverting the driving signal to obtain three-phase inverter current and outputting the three-phase inverter current to the three-phase asynchronous motor to work;
the current amplification circuit is used for amplifying any single-phase current in the three-phase inverter current to obtain an amplified current signal and outputting the amplified current signal to the control circuit;
the control circuit is used for carrying out timing judgment according to the single-phase current corresponding to the amplified current signal and carrying out power-off protection on the three-phase asynchronous motor based on a judgment result.
2. The overload protection circuit for the three-phase asynchronous motor according to claim 1, wherein the power supply circuit comprises a voltage division circuit, a voltage regulation circuit and an inductive coupling circuit;
the voltage division circuit is used for dividing the voltage of the accessed mains supply;
the voltage regulating circuit is used for regulating the divided voltage;
the inductive coupling circuit is used for carrying out inductive coupling processing according to the regulated voltage so as to provide different voltages for the driving circuit, the control circuit, the inverter circuit and the current amplifying circuit.
3. The overload protection circuit of the three-phase asynchronous motor according to claim 2, wherein the voltage dividing circuit comprises resistors R19, R20, R21, R23 and R25, capacitors C3, C4, and diodes D9 and D10, wherein the resistors R19, R20, R21, R23 and R25 are sequentially connected in series, one end of the capacitor C3 is connected to a common terminal of the resistors R21 and R23, the other end of the capacitor C3 is connected to ground, two ends of the capacitor C4 are connected in parallel to two ends of the resistors R23 and R25, and the diodes D9 and D10 are reversely connected to a common terminal of the resistors C4 and the resistors R23 and R25;
the voltage regulating circuit comprises a voltage regulating chip U7, resistors R30, R32, R36, R42 and R45, capacitors C21, C22, C33, C37, C38 and a diode D14, wherein four DRAIN ends of the U7 are connected with the anode of the D10, the VDD end of the U7 is connected into the R30 and D14 which are connected in series and the C21 and C22 which are connected in parallel, the FB end of the U7 is connected into the R32 and R36 which are connected in series and the C33 and R42 which are connected in parallel, and the COMP end of the U7 is connected into the R45, C37 and C38 which are connected in series in parallel;
the inductive coupling circuit comprises an inductive coupling coil T1, and the inductive coupling coil T1 comprises a first coupling main coil, a second coupling main coil, a third coupling main coil, a fourth coupling main coil, a first coupling auxiliary coil, a second coupling auxiliary coil and a third coupling auxiliary coil;
the two ends of the coil of the first coupling main coil are respectively connected to the common ends of R21 and C3 and the positive end of D10, and are used for connecting a first divided voltage of commercial power, the first coupling auxiliary coil is coupled with the first coupling main coil to provide a positive voltage and a negative voltage for driving a W phase in a driving circuit, the negative voltage output by the W phase in an inverter circuit, the second coupling auxiliary coil is coupled with the first coupling main coil to provide a positive voltage and a negative voltage for driving a V phase in the driving circuit, the negative voltage output by the V phase in the inverter circuit, the third coupling auxiliary coil is coupled with the first coupling main coil to provide a positive voltage and a negative voltage for driving a U phase in the driving circuit, and the negative voltage output by the U phase in the inverter circuit;
the second coupling main coil and the second coupling auxiliary coil are coupled to provide three-phase public voltage for the driving circuit, the third coupling main coil and the second coupling auxiliary coil are coupled to provide voltage for the current amplifying circuit and the control circuit, and the fourth coupling main coil and the third coupling auxiliary coil are coupled to provide voltage for the display circuit.
4. The overload protection circuit of the three-phase asynchronous motor according to claim 3, wherein the output end of the first coupling secondary coil comprises three ends, wherein the first end is connected to a diode D7 to output a positive voltage for driving a W phase in the driving circuit, the second end directly outputs a negative voltage for driving the W phase in the inverter circuit, the third end is connected to a diode D8 to output a negative voltage for driving the W phase in the driving circuit, capacitors C1 and C2 are connected in parallel between the first end and the second end, and capacitors C5 and C6 are connected in parallel between the second end and the third end;
the output end of the second coupling auxiliary coil also comprises three ends, wherein a first end is connected to a diode D11 and then outputs a positive voltage for driving a V phase in the driving circuit, a second end directly outputs a negative voltage for outputting the V phase in the inverter circuit, a third end is connected to a diode D15 and then outputs a negative voltage for driving the V phase in the driving circuit, capacitors C13 and C14 are connected between the first end and the second end in parallel, and capacitors C19 and C20 are connected between the second end and the third end in parallel;
the output end of the third coupling auxiliary coil also comprises three ends, wherein a first end is connected to a diode D17 and then outputs a positive voltage for driving a U phase in the driving circuit, a second end directly outputs a negative voltage for outputting the U phase in the inverter circuit, a third end is connected to a diode D19 and then outputs a negative voltage for driving the U phase in the driving circuit, capacitors C27 and C28 are connected between the first end and the second end in parallel, and capacitors C31 and C32 are connected between the second end and the third end in parallel;
the output end of the second coupling main coil also comprises three ends, wherein a first end is connected with a diode D12 and then outputs three-phase common positive voltage, a second end is grounded, a third end is connected with a diode D13 and then outputs three-phase common negative voltage, capacitors C10, C11 and C12 are connected between the first end and the second end in parallel, and capacitors C15, C16 and C17 are connected between the second end and the third end in parallel;
the output end of the third coupling main coil comprises two ends, wherein the first end is connected with a diode D16 and then outputs forward voltage to a voltage reduction chip U8 after passing through a resistor R44, the second end is grounded, and the voltage reduction chip U8 outputs voltage to the power ends of the current amplification circuit and the control circuit after reducing voltage;
the output end of the fourth coupling main coil comprises two ends, wherein the first end is connected to the diode D18 and outputs forward voltage to the voltage stabilizing diode U9 after passing through the resistor R43, the second end is grounded, and the voltage reducing chip U9 outputs voltage to the power supply end of the display circuit after stabilizing voltage.
5. The overload protection circuit for the three-phase asynchronous motor according to claim 4, wherein the driving circuit comprises six optical coupling signal amplifiers and six current regulating circuits, and the six optical coupling signal amplifiers and the six current regulating circuits are connected in a one-to-one correspondence manner;
the VCC end of the first optocoupler signal amplifier U1 is connected to the positive voltage of the U phase, the GND end is connected to the negative voltage of the U phase, the ANODE end is connected to the UP input signal, and the Vout end inputs the UP driving signal through the first current regulating circuit;
the VCC end of the second optocoupler signal amplifier U2 is connected to the positive voltage of the W phase, the GND end is connected to the negative voltage of the W phase, the ANODE end is connected to a WP input signal, and the Vout end is connected to a WP driving signal through the second current regulating circuit;
the VCC end of the third optocoupler signal amplifier U3 is connected to the positive voltage of the V phase, the GND end is connected to the negative voltage of the V phase, the ANODE end is connected to the VP input signal, and the Vout end is connected to the VP driving signal through the third current regulating circuit;
a VCC end of a fourth optocoupler signal amplifier U4 is connected into the three-phase public positive voltage, a GND end is connected into the three-phase public negative voltage, an ANODE end is connected into a UN input signal, and a Vout end is connected into a UN driving signal through a fourth current regulating circuit;
a VCC end of a fifth optocoupler signal amplifier U5 is connected to the three-phase common positive voltage, a GND end is connected to the three-phase common negative voltage, an ANODE end is connected to a WN input signal, and a Vout end is connected to a WN driving signal through a fifth current regulating circuit;
the VCC end of the sixth optocoupler signal amplifier U6 is connected to the three-phase public positive voltage, the GND end is connected to the three-phase public negative voltage, the ANODE end is connected to the VN input signal, and the Vout end is connected to the VN driving signal through the sixth current regulating circuit.
6. The overload protection circuit for the three-phase asynchronous motor according to claim 5, wherein the inverter circuit comprises six IGBT circuits;
the first IGBT circuit is connected with the UP driving signal, the second IGBT circuit is connected with the UN driving signal, and the first IGBT circuit and the second IGBT circuit are used for carrying out AC-DC inversion according to the UN driving signal and the UN driving signal to obtain U-phase output current and outputting the U-phase output current to a U-phase input end of the three-phase asynchronous motor;
the third IGBT circuit is connected with the VP driving signal, the fourth IGBT circuit is connected with the VN driving signal, and the third IGBT circuit and the fourth IGBT circuit are used for performing alternating-direct inversion according to the VN driving signal and the VN driving signal to obtain a V-phase output current and outputting the V-phase output current to a V-phase input end of the three-phase asynchronous motor;
the fifth IGBT circuit is connected with the WP driving signal, the sixth IGBT circuit is connected with the WN driving signal, and the fifth IGBT circuit and the sixth IGBT circuit are used for carrying out AC-DC inversion according to the VN driving signal and the WN driving signal to obtain W-phase output current and outputting the W-phase output current to the W-phase input end of the three-phase asynchronous motor.
7. The overload protection circuit for the three-phase asynchronous motor according to claim 6, wherein the current amplification circuit comprises a current amplifier U20A, resistors R86, R90, R93, R96, R99, R102, capacitors C43 and C49;
the power supply end of the current amplifier U20A is connected with the output voltage of the third main coil after being stepped down by the step-down chip U8, the non-inverting input end is connected with the R96, the R99, the R102 and the C49 in parallel, the inverting input end is connected with the R90, the R86 is simultaneously connected with the inverting input end and the output end, and the input end is connected with the R93 and the C43 in series and then outputs an amplified current signal to the control circuit.
8. The overload protection circuit for the three-phase asynchronous motor according to claim 7, wherein the control circuit comprises a main control chip U12, the VDD terminal of the U12 is connected to the output voltage of the third main winding after being stepped down by a step-down chip U8, pins P10, P11, P12, P13, P14 and P15 output the WN input signal, the VN input signal, the WP input signal, the VP input signal, the UN input signal and the UP input signal respectively, and pin P20 is connected to the amplified current signal.
9. An overload protection method for a three-phase asynchronous motor based on the overload protection circuit for the three-phase asynchronous motor according to any one of claims 1 to 8, wherein the method comprises the following steps:
any phase current of the three-phase asynchronous motor is collected through the control circuit, and whether the current phase current is larger than an overload current threshold value is judged at preset time intervals through the time of a timer;
if the value is larger than the preset value, adding 1 to the overload protection counting value;
if not, subtracting 1 from the overload protection count value;
monitoring whether the overload protection count value exceeds a set count threshold value in real time;
if the number of the overload protection counter values exceeds the preset value, a stop instruction is sent to drive the three-phase asynchronous motor to stop, and if the number of the overload protection counter values does not exceed the preset value, the overload protection counter values are continuously monitored.
10. The overload protection method for the three-phase asynchronous motor according to claim 9, further comprising:
and monitoring the timing duration of the timer in real time, and if the timing duration of the timer exceeds the preset duration, outputting a shutdown instruction to drive the three-phase asynchronous motor to be shut down.
CN202210584267.4A 2022-05-27 2022-05-27 Overload protection circuit and method for three-phase asynchronous motor Active CN114678834B (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116191383A (en) * 2023-03-06 2023-05-30 江苏吉泰科电气有限责任公司 Overcurrent protection method and circuit

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101882779A (en) * 2010-07-21 2010-11-10 深圳市库马克新技术股份有限公司 High voltage converter with differential protection
CN102291065A (en) * 2011-09-01 2011-12-21 北京信息科技大学 Brushless direct current motor control device based on DSP (Digital Signal Processor)
CN103262408A (en) * 2010-12-22 2013-08-21 富士电机株式会社 Power conversion apparatus
CN203387450U (en) * 2013-06-03 2014-01-08 浙江桐庐电机厂 A permanent magnetism alternating current synchronization motor system used for a blower fan coil pipe
CN109038498A (en) * 2018-08-29 2018-12-18 深圳腾势新能源汽车有限公司 Protection system for motor
CN213402849U (en) * 2020-11-11 2021-06-08 石家庄铁道大学 Three-phase inverter with high control precision

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101882779A (en) * 2010-07-21 2010-11-10 深圳市库马克新技术股份有限公司 High voltage converter with differential protection
CN103262408A (en) * 2010-12-22 2013-08-21 富士电机株式会社 Power conversion apparatus
CN102291065A (en) * 2011-09-01 2011-12-21 北京信息科技大学 Brushless direct current motor control device based on DSP (Digital Signal Processor)
CN203387450U (en) * 2013-06-03 2014-01-08 浙江桐庐电机厂 A permanent magnetism alternating current synchronization motor system used for a blower fan coil pipe
CN109038498A (en) * 2018-08-29 2018-12-18 深圳腾势新能源汽车有限公司 Protection system for motor
CN213402849U (en) * 2020-11-11 2021-06-08 石家庄铁道大学 Three-phase inverter with high control precision

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116191383A (en) * 2023-03-06 2023-05-30 江苏吉泰科电气有限责任公司 Overcurrent protection method and circuit
CN116191383B (en) * 2023-03-06 2023-09-29 江苏吉泰科电气有限责任公司 Overcurrent protection method and circuit

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