CN114814575A - Motor locked-rotor detection method and device, external variable frequency driver and medium - Google Patents

Motor locked-rotor detection method and device, external variable frequency driver and medium Download PDF

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CN114814575A
CN114814575A CN202210438400.5A CN202210438400A CN114814575A CN 114814575 A CN114814575 A CN 114814575A CN 202210438400 A CN202210438400 A CN 202210438400A CN 114814575 A CN114814575 A CN 114814575A
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value
motor
voltage
axis
back electromotive
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贺小林
刘志辉
熊光灿
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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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
    • 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
    • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
    • H02P21/13—Observer control, e.g. using Luenberger observers or Kalman filters
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Control Of Ac Motors In General (AREA)

Abstract

The present disclosure provides a motor locked-rotor detection method, a device, an external variable frequency driver and a storage medium, wherein the method comprises: acquiring a back electromotive force voltage frequency value determined by a state observer; and judging whether the counter electromotive voltage frequency value is smaller than the counter electromotive voltage frequency threshold value, and if so, determining that the motor has a locked-rotor fault. The method and the device can detect whether the motor has a locked-rotor fault or not based on the counter electromotive force voltage frequency and the relation between the phase voltage vector and the counter electromotive force vector of the motor winding, improve the ability of the external driver for identifying the locked-rotor state of the motor, and improve the operation reliability of the external variable frequency driver.

Description

Motor locked-rotor detection method and device, external variable frequency driver and medium
Technical Field
The invention relates to the technical field of variable frequency speed regulation, in particular to a motor locked-rotor detection method and device, an external variable frequency driver and a storage medium.
Background
The frequency conversion equipment such as the frequency conversion air conditioning unit has the advantages of energy conservation, comfort and the like. The frequency conversion driver of the frequency conversion equipment is usually built in the motor, and has the defects of large motor volume, high cost and the like. The motor is driven by the external variable frequency driver, so that the motor has the advantages of reducing the size and cost of the motor and the like, but the motor is driven by a position sensor-free mode, so that the problem that the motor stalling cannot be directly detected is solved, and therefore, a technical scheme suitable for detecting the motor stalling by the external variable frequency driver is needed.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a method and an apparatus for detecting a locked-rotor of a motor, an external variable frequency driver, and a storage medium, which can detect whether a locked-rotor fault occurs in the motor according to a back electromotive voltage frequency.
According to a first aspect of the present disclosure, a method for detecting a locked-rotor of a motor is provided, which is applied to an external variable frequency driver, wherein the external variable frequency driver includes: a state observer and a magnetic field vector orientation controller; the method comprises the following steps: acquiring a back electromotive force voltage frequency value determined by the state observer; the state observer acquires the current value of a three-phase winding of the motor in real time, and determines the counter electromotive voltage frequency value according to the current value of the three-phase winding; judging whether the counter electromotive force voltage frequency value is smaller than a counter electromotive force voltage frequency threshold value or not; and if so, determining that the motor has a locked-rotor fault.
Optionally, if the back electromotive force voltage frequency value is greater than or equal to the back electromotive force voltage frequency threshold, determining a first effective value of a back electromotive force voltage vector modulus value corresponding to the motor and a second effective value of a stator winding phase voltage vector modulus value, and determining whether the motor has a locked rotor fault based on a comparison relationship between the first effective value and the second effective value.
Optionally, the determining whether the locked-rotor fault occurs to the motor based on the comparison relationship between the first effective value and the second effective value includes: and if the first effective value is larger than the second effective value, determining that the motor has a locked-rotor fault.
Optionally, the determining a first effective value of a back-emf voltage vector norm value corresponding to the motor comprises: acquiring a d-axis counter electromotive voltage value and a q-axis counter electromotive voltage value determined by the state observer; wherein the state observer determines the d-axis back electromotive force voltage value and the q-axis back electromotive force voltage value based on a current value of the three-phase winding; obtaining a first period value of the PWM control signal and a second period value corresponding to the back electromotive force voltage frequency value; calculating the first effective value based on the d-axis back electromotive force voltage value, the q-axis back electromotive force voltage value, the first period value, and the second period value.
Optionally, the calculating the first effective value based on the d-axis back emf voltage value, the q-axis back emf voltage value, the first period value, and the second period value comprises: calculating the square sum of the d-axis back electromotive force voltage value and the q-axis back electromotive force voltage value, and determining a first numerical value corresponding to the back electromotive force voltage; determining an accumulated value of the first numerical value based on the first numerical value and the first periodic value; and calculating the quotient of the accumulated value of the first numerical value and the second period value, and taking the square root of the quotient as the first effective value.
Optionally, the determining a second effective value of a stator winding phase voltage vector magnitude corresponding to the electric machine comprises: acquiring a d-axis voltage value and a q-axis voltage value determined by the magnetic field vector orientation controller; wherein the state observer determines a d-axis stator current value and a q-axis stator current value based on current values of the three-phase winding; the magnetic field vector orientation controller processes based on the d-axis stator current value and the q-axis stator current value to obtain a d-axis voltage value and a q-axis voltage value for controlling the motor; calculating the second effective value based on the d-axis voltage value, the q-axis voltage value, the first period value, and the second period value.
Optionally, the calculating the second effective value based on the d-axis voltage value, the q-axis voltage value, the first periodic value, and the second periodic value comprises: calculating the square sum of the d-axis voltage value and the q-axis voltage value, and determining a second value corresponding to the phase voltage of the stator winding; determining an accumulated value of the second numerical value based on the second numerical value and the first periodic value; and calculating the quotient of the accumulated value of the second numerical value and the second period value, and taking the square root of the quotient as the second effective value.
Optionally, in a case where the state of the motor is determined to be normal and a start-up instruction is received, the back electromotive force voltage frequency value determined by the state observer is acquired.
Optionally, the magnetic field vector orientation controller controls the motor to stop running under the condition that the motor is judged to have the locked-rotor fault.
According to a second aspect of the present disclosure, a motor stalling detection device is provided, which is applied to an external variable frequency driver, wherein the external variable frequency driver includes: a state observer and a magnetic field vector orientation controller; the motor locked rotor detection device comprises: the frequency value acquisition module is used for acquiring a back electromotive force voltage frequency value determined by the state observer; the state observer acquires the current value of a three-phase winding of the motor in real time, and determines the counter electromotive voltage frequency value according to the current value of the three-phase winding; the frequency value judging module is used for judging whether the counter electromotive voltage frequency value is smaller than a counter electromotive voltage frequency threshold value; a first fault determination module configured to determine that a locked-rotor fault occurs in the motor if the back electromotive voltage frequency value is less than a back electromotive voltage frequency threshold.
Optionally, the method further comprises: and the second fault determination module is used for determining a first effective value of a counter electromotive voltage vector modulus corresponding to the motor and a second effective value of a stator winding phase voltage vector modulus if the counter electromotive voltage frequency value is greater than or equal to a counter electromotive voltage frequency threshold, and judging whether the motor has a locked rotor fault or not based on a comparison relation between the first effective value and the second effective value.
Optionally, the second fault determination module includes: and the locked-rotor fault determining unit is used for determining that the locked-rotor fault occurs in the motor if the first effective value is greater than the second effective value.
Optionally, the second fault determination module includes: the first data acquisition unit is used for acquiring the d-axis counter electromotive voltage value and the q-axis counter electromotive voltage value determined by the state observer; wherein the state observer determines the d-axis back electromotive force voltage value and the q-axis back electromotive force voltage value based on a current value of the three-phase winding; obtaining a first period value of the PWM control signal and a second period value corresponding to the back electromotive force voltage frequency value; a first calculation unit to calculate the first effective value based on the d-axis counter-electromotive-force voltage value, the q-axis counter-electromotive-force voltage value, the first period value, and the second period value.
Optionally, the first calculating unit is specifically configured to calculate a sum of squares of the d-axis back electromotive voltage value and the q-axis back electromotive voltage value, and determine a first numerical value corresponding to the back electromotive voltage; determining an accumulated value of the first numerical value based on the first numerical value and the first periodic value; and calculating the quotient of the accumulated value of the first numerical value and the second period value, and taking the square root of the quotient as the first effective value.
Optionally, the second fault determination module includes: a second data acquisition unit for acquiring the d-axis voltage value and the q-axis voltage value determined by the magnetic field vector orientation controller; wherein the state observer determines a d-axis stator current value and a q-axis stator current value based on current values of the three-phase winding; the magnetic field vector orientation controller processes based on the d-axis stator current value and the q-axis stator current value to obtain a d-axis voltage value and a q-axis voltage value for controlling the motor; a second calculation unit to calculate the second effective value based on the d-axis voltage value, the q-axis voltage value, the first period value, and the second period value.
Optionally, the second calculating unit is specifically configured to calculate a sum of squares of the d-axis voltage value and the q-axis voltage value, and determine a second value corresponding to the stator winding phase voltage; determining an accumulated value of the second numerical value based on the second numerical value and the first periodic value; and calculating the quotient of the accumulated value of the second numerical value and the second period value, and taking the square root of the quotient as the second effective value.
Optionally, the frequency value obtaining module is configured to obtain the back electromotive force voltage frequency value determined by the state observer when it is determined that the state of the motor is normal and a power-on instruction is received.
Optionally, the fault processing module is configured to control the motor to stop running through the magnetic field vector orientation controller when it is determined that the motor has a locked-rotor fault.
According to a third aspect of the present disclosure, there is provided a motor stalling detection device, including: a memory; and a processor coupled to the memory, the processor configured to perform the method as described above based on instructions stored in the memory.
According to a fourth aspect of the present disclosure, there is provided an external variable frequency drive comprising: the motor locked-rotor detection device is described above.
According to a fifth aspect of the present disclosure, there is provided a computer readable storage medium storing computer instructions for execution by a processor to perform the method as described above.
According to the motor locked-rotor detection method and device, the external variable frequency driver and the storage medium, aiming at the characteristic that the external variable frequency driver cannot directly detect the rotation condition of the motor rotor and the fluctuation of the sampling value of the phase current of the motor winding, whether a locked-rotor fault occurs in the motor can be detected based on the counter electromotive voltage frequency and the relation between the phase voltage vector and the counter electromotive voltage vector of the motor winding, the capacity of the external driver for identifying the locked-rotor state of the motor is improved, the running reliability of the external variable frequency driver is improved, and the use sensitivity of a user is improved.
Drawings
In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without inventive exercise.
Fig. 1 is a schematic flow diagram of one embodiment of a motor stall detection method according to the present disclosure;
fig. 2 is a schematic flow chart illustrating a process of determining a first effective value of a back electromotive force voltage vector norm value corresponding to a motor in an embodiment of a motor stall detection method according to the present disclosure;
fig. 3 is a schematic flow chart illustrating a process of determining a second effective value of a stator winding phase voltage vector magnitude corresponding to the motor in an embodiment of the motor stall detection method according to the present disclosure;
FIG. 4 is a schematic flow chart diagram of another embodiment of a motor stall detection method according to the present disclosure;
FIG. 5 is a schematic diagram of the control of the motor by the external variable frequency drive according to the present disclosure;
FIG. 6 is a block schematic diagram of one embodiment of a motor stall detection apparatus according to the present disclosure;
FIG. 7 is a block schematic diagram of another embodiment of a motor stall detection apparatus according to the present disclosure;
FIG. 8 is a block diagram illustration of a second fault determination module in an embodiment of a motor stall detection apparatus according to the present disclosure;
fig. 9 is a block schematic diagram of yet another embodiment of a motor stall detection apparatus according to the present disclosure.
Detailed Description
The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the disclosure are shown. The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.
The terms "first" and "second" are used hereinafter only for descriptive distinction and have no other special meaning.
Fig. 1 is a schematic flow chart of an embodiment of a method for detecting a locked rotor of a motor according to the present disclosure, where the method for detecting a locked rotor of a motor is applied to an external variable frequency driver, and the external variable frequency driver is a variable frequency driver disposed outside the motor, as shown in fig. 1:
and step 101, obtaining a counter electromotive force voltage frequency value determined by the state observer.
In one embodiment, as shown in FIG. 5, the external variable frequency drive 50 is disposed external to the motor 55, and the motor 55 is a three-phase motor. The external variable frequency drive 50 includes a state observer 53 and a magnetic field vector orientation controller 52, among other things. The motor locked-rotor detection method can be applied to the motor locked-rotor detection device 51, and the motor locked-rotor detection device 51 can be a module which is arranged independently and can also be integrated with models such as a magnetic field vector directional controller 52.
The state observer 53 is used for estimating the real-time state of the electric machine 52, and the state observer 53 may be any of various existing state observers, such as a luneberg observer. The magnetic field vector orientation controller 52 generates PWM control signals for controlling the motor, and the magnetic field vector orientation controller 52 may be any of a variety of existing magnetic field vector orientation controllers.
The magnetic field vector orientation controller 52 controls the rotation of the motor 55, and controls the stator winding of the motor 55 to generate a current vector with an included angle of 90 ° or more according to the rotor magnetic flux direction of the motor 55, so as to drag the motor 55 to rotate. The field vector orientation controller 52 sends PWM control signals for controlling the motor 55, which are used to control the inverter 54 to generate the ac voltage signals required by the motor 55.
The state observer 53 collects the current values of the three-phase windings of the motor 55 in real time, and determines the back electromotive voltage frequency value according to the current values of the three-phase windings. As shown in fig. 5, the state observer 53 samples and detects three-phase winding phase currents of the motor 55 in real time, where U is a U-phase end of the motor 55, V is a V-phase end of the motor 55, W is a W-phase end of the motor 55, Iu is a U-phase winding current sampling value of the motor 55, Iv is a V-phase winding current sampling value of the motor 55, Iw is a W-phase winding current sampling value of the motor 55, and Tp is a period value of the PWM control signal.
The state observer 53 outputs state values of Ed, Eq, Id, Iq, We, and the like, where Ed is a d-axis back electromotive force voltage value of the rotating coordinate system, Eq is a q-axis back electromotive force voltage value of the rotating coordinate system, Id is a d-axis stator current value of the rotating coordinate system, Iq is a q-axis stator current value of the rotating coordinate system, and We is a back electromotive force voltage frequency value estimated (determined) by the state observer 55.
Step 102, judging whether the counter electromotive voltage frequency value is smaller than a counter electromotive voltage frequency threshold value; if so, step 103 is entered.
And 103, determining that the motor has a locked-rotor fault.
In one embodiment, in step 102, when it is determined that the back emf voltage frequency value is greater than or equal to the back emf voltage frequency threshold, step 104 is entered.
And 104, determining a first effective value of a back electromotive force voltage vector modulus value corresponding to the motor and a second effective value of a stator winding phase voltage vector modulus value, and judging whether the motor has a locked-rotor fault or not based on a comparison relation between the first effective value and the second effective value.
In one embodiment, in the case where the state of the motor is determined to be normal and the start-up instruction is received, the back electromotive voltage frequency value determined by the state observer is acquired. Various methods can be adopted for judging whether the motor has the locked rotor fault. For example, if the first effective value is greater than the second effective value, it is determined that the locked-rotor fault has occurred in the motor. Under the condition that the motor is judged to have the locked-rotor fault, the motor is controlled to stop running through the magnetic field vector orientation controller, for example, the PWM control signal output by the magnetic field vector orientation controller is controlled to change so as to control the motor to stop running.
According to the motor locked-rotor detection method, whether a locked-rotor fault occurs in the motor is detected based on the counter electromotive force voltage frequency and the comparison relation between the motor winding phase voltage vector and the counter electromotive force vector aiming at the characteristic that the external variable frequency driver cannot directly detect the rotation condition of the motor rotor and the fluctuation of the sampling value of the motor winding phase current, the problem that the external variable frequency driver is difficult to detect the locked-rotor of the motor is solved, and the control reliability of the external variable frequency driver is improved.
Fig. 2 is a schematic flowchart of determining a first effective value of a back electromotive voltage vector norm value corresponding to a motor in an embodiment of a motor stalling detection method according to the present disclosure, as shown in fig. 2:
in step 201, a d-axis back electromotive force voltage value and a q-axis back electromotive force voltage value determined by the state observer are obtained.
The state observer determines a d-axis back electromotive voltage value and a q-axis back electromotive voltage value based on the current values of the three-phase windings. As shown in fig. 5, the state observer 53 samples and detects three-phase winding phase currents Iu, Iv, and Iw of the motor 55 in real time, and the state observer 53 outputs Ed and Eq, where Ed is a d-axis back electromotive voltage value of the rotating coordinate system and Eq is a q-axis back electromotive voltage value of the rotating coordinate system.
Step 202 obtains a first period value of the PWM control signal and a second period value corresponding to the back emf voltage frequency value.
The first period value of the PWM control signal can be obtained from the field vector orientation controller 52, the first period value being Tp. A second period value corresponding to the value of the back emf voltage frequency can be obtained from the state observer 53, the second period value being the period value Te of the We frequency.
Step 203, calculating a first effective value based on the d-axis back electromotive voltage value, the q-axis back electromotive voltage value, the first period value and the second period value.
The first significant value may be calculated in a variety of ways. For example, a square sum of the d-axis back electromotive voltage value and the q-axis back electromotive voltage value is calculated, and a first numerical value corresponding to the back electromotive voltage is determined; determining an accumulated value of the first value based on the first value and the first cycle value; and calculating the quotient of the accumulated value of the first numerical value and the second period value, and taking the square root of the quotient as a first effective value.
Three-phase to two-phase coordinate transformation is required for the control of the motor 55 for the purpose of separating the relevant variables and controlling them separately. The d-q coordinate system is an existing rotating coordinate system, and a formula for calculating a first effective value of a back electromotive force voltage vector modulus value corresponding to the motor is as follows:
Es＝Ed 2 +Eq 2 (1-1)；
where Es is a first value corresponding to the back electromotive voltage, Ed is a d-axis back electromotive voltage value of the rotating coordinate system, and Eq is a q-axis back electromotive voltage value of the rotating coordinate system.
Essum＝Essum+Es*Tp (1-2)；
Essum is an accumulated value of a first value, and Tp is a first period value of the PWM control signal.
Figure BDA0003613897750000091
Where Esrms is a first effective value of a back emf voltage vector magnitude corresponding to the motor, and Te is a second period value corresponding to a back emf voltage frequency value, i.e., Te is a period value of the We frequency.
Fig. 3 is a schematic flowchart of determining a second effective value of a stator winding phase voltage vector magnitude corresponding to the motor in an embodiment of the motor stalling detection method according to the disclosure, as shown in fig. 3:
step 301, obtaining a d-axis voltage value and a q-axis voltage value determined by the magnetic field vector orientation controller.
In one embodiment, the state observer determines a d-axis stator current value and a q-axis stator current value based on current values of the three-phase windings, and the magnetic field vector orientation controller performs correction processing based on the d-axis stator current value and the q-axis stator current value to obtain a d-axis voltage value and a q-axis voltage value for controlling the motor.
As shown in fig. 5, the magnetic field vector orientation controller 52 implements magnetic field vector orientation control, which may be an existing magnetic field vector orientation controller including existing modules such as a speed loop and a current loop. The magnetic field vector orientation controller performs current correction based on the currents Id and Iq and the target regulation current to obtain voltages Vd and Vq, and controls the motor 55 based on the voltages Vd and Vq.
For example, the current loop in the magnetic field vector orientation controller 52 may employ PI regulation control, with the output of the current loop as the voltage components Vd, Vq of the d-q coordinate system; calculating voltage components V alpha and V beta of an alpha beta coordinate system by Vd and Vq of the voltage components through PARK inverse transformation; the voltage components V α and V β calculate the duty ratios of the six power tubes in the power module through SVPWM to form six paths of PWM signals, and the motor 55 can be driven to operate through the PWM signals.
Step 302, a second effective value is calculated based on the d-axis voltage value, the q-axis voltage value, the first period value, and the second period value.
The second significant value may be calculated in a variety of ways. For example, the sum of the squares of the d-axis voltage value and the q-axis voltage value is calculated, and a second value corresponding to the stator winding phase voltage is determined; determining an accumulated value of the second value based on the second value and the first period value; and calculating the quotient of the accumulated value of the second numerical value and the second period value, and taking the square root of the quotient as a second effective value.
The formula for calculating the second effective value of the stator winding phase voltage vector modulus value corresponding to the motor is as follows:
Vs＝Vd 2 +Vq 2 (1-4)；
and Vd is a d-axis voltage value determined by the magnetic field vector orientation controller, Vq is a q-axis voltage value determined by the magnetic field vector orientation controller, and Vs is a second value corresponding to the phase voltage of the stator winding.
Vssum＝Vssum+Vs*Tp (1-5)；
Vssum is an accumulated value of a second value corresponding to the stator winding phase voltage, and Tp is a first period value of the PWM control signal.
Figure BDA0003613897750000101
Where Vsrms is a second effective value of the stator winding phase voltage vector mode value, and Te is a second period value corresponding to the counter electromotive voltage frequency value, that is, Te is the period value of the We frequency.
In one embodiment, three-phase to two-phase coordinate transformation is required for control of the motor 55 for the purpose of separating the relevant variables and performing separate control, with the d-q coordinate system being the existing rotating coordinate system. The external variable frequency driver is connected with a motor through a U-phase end, a V-phase end and a W-phase end of a three-phase winding of a stator, and current signals of the three-phase winding are measured to be used as input signals of a state observer.
Due to the difference of current sampling circuit wiring, current sampling sensor type selection, main chip ADC sampling module precision and the like, when a motor locked-rotor fault occurs, if the phase current sampling circuit wiring is good, the sensor type selection and the ADC sampling precision are high, the sampling real-time value of the phase current (Iu, Iv and Iw) of a three-phase winding is changed without periodicity, at the moment, the state observer outputs the rotating speed We, the back electromotive voltage Ed and Eq, the current Id and Iq and the like to be 0, at the moment, the locked-rotor condition of the motor can be detected by judging whether We is smaller than a back electromotive voltage frequency threshold value WeStallTH which is set for judging the motor locked-rotor fault, and otherwise, the phase current sampling real-time value has periodic change. At the moment, the state observer can estimate the rotating speed We and the back electromotive force voltage values Ed and Eq according to the phase current of the three-phase winding, and because the motor does not actually rotate at the moment, numerical values output by the state observer, such as We, Ed and Eq, are not real, and the locked-rotor state of the motor cannot be directly judged through the rotating speed We.
The motor stator voltage equation Is Vs ═ Rs × Is + Ls × pIs + espeal, where Vs Is the stator voltage, Rs Is the resistance value, Is the current value, Ls × pIs corresponds to the inductance, and espeal Is the back electromotive voltage. When the motor Is in a locked state, the current Is in the motor winding Is accompanied by the jitter condition, so that Vs Is Rs Is + Ls pIs, and Is more than 0; the reason for this phenomenon is that the phase current value of the three-phase stator winding is periodically changed due to the influence of ADC sampling wiring of the driving controller, sampling precision of an ADC module of a chip and the like, so that the state observer follows the phase current change of the stator winding to estimate rotating speeds We, Ed, Eq and the like.
The voltage Vs applied to the stator winding of the motor by the variable-frequency driver is calculated by closed-loop feedback of the deviation between the target rotating speed and the estimated rotating speed We, and the value of Vs is not very large because the output We of the state observer changes along with the target rotating speed, so that the situation that the voltage value Es is larger than the voltage Vs can occur in the motor control based on the state observer, and the situation can only occur when the driving controller board cannot reach the optimal value and the state observer is used for estimating the position of the rotor. In the state that the motor does not rotate actually, Esreal (actual back electromotive voltage) is 0V, and the available Vs is larger than 0V, so the relationship between Es and Vs can be calculated through Ed and Eq output by the state observer, and under the condition that the We value of the state observer is larger than WeStallTH, if the Es voltage is larger than the Vs voltage, the motor is in a locked-rotor state, otherwise, the motor is not in the locked-rotor state.
Fig. 4 is a schematic flow chart of another embodiment of the motor stalling detection method according to the disclosure, as shown in fig. 4:
step 401, judging whether a fault exists, if yes, returning, if not, entering step 402.
Detecting whether a fault exists, if so, returning and waiting for fault elimination, and if not, waiting for a starting instruction, wherein the fault comprises other faults except a locked rotor fault, such as faults of motor phase loss, motor step loss, motor overcurrent and the like, if so, the state of the motor is abnormal, and if not, the state of the motor is normal.
Step 402, judging whether a starting instruction exists, if not, returning, and if yes, entering step 403. The starting-up instruction sent by the upper computer can be received.
And step 403, acquiring a back electromotive force voltage frequency value determined by the state observer.
After receiving a starting instruction, detecting three-phase winding phase currents Iu, Iv and Iw of the motor in real time, inputting the three-phase winding phase currents Iu, Iv and Iw into a state observer, enabling the state observer to operate and outputting motor state quantities such as We, Ed and Eq.
Step 404, determining whether the back electromotive force voltage frequency value is smaller than the back electromotive force voltage frequency threshold, if yes, going to step 407, and if no, going to step 405.
If the state observer can accurately detect the back electromotive force voltage frequency value We of the motor rotor, when We is smaller than a preset back electromotive force voltage frequency threshold value WeStallTH, the motor is judged to be in a locked-rotor state, and the step 407 is entered; if the state observer abnormally operates, the output We of the state observer follows the target rotating speed, the estimated value of Es (the estimated value of Es is not the real counter electromotive force value on the motor winding at the moment) is larger than the voltage value applied to the motor Vs by the control, and the motor is judged to be in a non-locked-rotor state at the moment.
Step 405, calculating a first effective value of a back electromotive force voltage vector modulus value corresponding to the motor and a second effective value of a stator winding phase voltage vector modulus value.
Step 406, determining whether the first valid value is greater than the second valid value, if yes, entering step 407, and if no, returning.
When We is detected to be smaller than WeStallTH, judging that the motor is in a locked-rotor state; and when the first effective value Esrms of the calculated back electromotive force voltage vector modulus is larger than the second effective value Vsrms of the stator winding phase voltage vector modulus, judging that the motor is in a locked-rotor state, reporting a locked-rotor fault of the motor, stopping the unit, and repeating the control flow.
Step 407, determining that the motor has a locked-rotor fault, and stopping the motor.
The magnetic field vector orientation controller can be controlled to output PWM signals to control the inverter not to perform direct current voltage conversion into alternating current voltage any more, and the motor can automatically stop running due to system resistance.
In one embodiment, as shown in fig. 5, the present disclosure provides a motor stalling detection device 51 applied to an external variable frequency drive 50, wherein the external variable frequency drive 50 comprises a state observer 53, a magnetic field vector orientation controller 52, and the like. As shown in fig. 6, the motor stalling detection device 51 includes: a frequency value obtaining module 511, a frequency value judging module 512, and a first failure determining module 513.
The frequency value obtaining module 511 obtains a back electromotive force voltage frequency value determined by the state observer, wherein the state observer 53 collects a current value of a three-phase winding of the motor 55 in real time, and determines the back electromotive force voltage frequency value according to the current value of the three-phase winding. The frequency value obtaining module 511 may obtain the back electromotive voltage frequency value determined by the state observer in a case where the state of the motor is determined to be normal and the start-up instruction is received.
The frequency value determination module 512 determines whether the back emf voltage frequency value is less than the back emf voltage frequency threshold. The first fault determination module 513 determines that the locked rotor fault has occurred with the motor if the back emf voltage frequency value is less than the back emf voltage frequency threshold value.
In one embodiment, the external vfd 50 further includes a second fault determining module 514, if the back emf voltage frequency value is greater than or equal to the back emf voltage frequency threshold, the second fault determining module 514 determines a first effective value of a back emf voltage vector modulus value and a second effective value of a stator winding phase voltage vector modulus value corresponding to the motor, and determines whether the motor has a locked-rotor fault based on a comparison between the first effective value and the second effective value.
As shown in fig. 7, the motor stalling detection device 51 includes a fault processing module 515, and the fault processing module 515 controls the motor to stop running through the magnetic field vector orientation controller in the case of judging that the motor stalls.
In one embodiment, as shown in fig. 8, the second fault determination module 514 includes a locked rotor fault determination unit 5141, a first data acquisition unit 5142, a first calculation unit 5143, a second data acquisition unit 5144, and a second calculation unit 5145. The locked-rotor fault determination unit 5141 determines that the locked-rotor fault occurs in the motor if the first effective value is greater than the second effective value.
The first data acquisition unit 5142 acquires the d-axis back electromotive force voltage value and the q-axis back electromotive force voltage value determined by the state observer; wherein the state observer 53 determines a d-axis counter electromotive voltage value and a q-axis counter electromotive voltage value based on the current values of the three-phase windings; the first data acquisition unit 5142 acquires a first period value of the PWM control signal and a second period value corresponding to the back electromotive voltage frequency value, and calculates a first effective value based on the d-axis back electromotive voltage value, the q-axis back electromotive voltage value, the first period value, and the second period value.
The first calculation unit 5143 calculates a sum of squares of the d-axis back electromotive force voltage value and the q-axis back electromotive force voltage value, determines a first numerical value corresponding to the back electromotive force voltage, and determines an accumulated value of the first numerical value based on the first numerical value and the first cycle value; the first calculation unit 5143 calculates a quotient of the accumulated value of the first value and the second period value, and takes the square root of the quotient as the first effective value.
The second data acquisition unit 5144 acquires the d-axis voltage value and the q-axis voltage value determined by the magnetic field vector orientation controller 52, wherein the state observer 53 determines the d-axis stator current value and the q-axis stator current value based on the current values of the three-phase windings; the magnetic field vector orientation controller 52 performs correction processing based on the d-axis stator current value and the q-axis stator current value to obtain a d-axis voltage value and a q-axis voltage value for controlling the motor; the second calculation unit 5145 calculates a second effective value based on the d-axis voltage value, the q-axis voltage value, the first period value, and the second period value.
The second calculation unit 5145 calculates the sum of squares of the d-axis voltage value and the q-axis voltage value, determines a second value corresponding to the stator winding phase voltage, and determines an accumulated value of the second value based on the second value and the first period value; the second calculating unit 5145 calculates a quotient of the accumulated value of the second numerical value and the second period value, and takes the square root of the quotient as the second effective value.
In one embodiment, as shown in fig. 9, the motor stall detection device may include a memory 92, a processor 91, a communication interface 93, and a bus 94. The memory 92 is used for storing instructions, the processor 91 is coupled to the memory 92, and the processor 91 is configured to execute the motor stall detection method described above based on the instructions stored in the memory 92.
The memory 92 may be a high-speed RAM memory, a non-volatile memory (non-volatile memory), or the like, and the memory 92 may be a memory array. The storage 92 may also be partitioned, and the blocks may be combined into virtual volumes according to certain rules. Processor 91 may be a central processing unit CPU, or an application Specific Integrated circuit asic, or one or more Integrated circuits configured to implement the motor stall detection method of the present disclosure.
In one embodiment, the present disclosure provides an external variable frequency drive, including the motor stall detection apparatus in any of the above embodiments.
In one embodiment, the present disclosure provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement a method as in any one of the above embodiments.
According to the motor stalling detection method and device, the external variable frequency driver and the storage medium in the embodiment, whether the motor stalls or not can be detected based on the counter electromotive voltage frequency and the relation between the phase voltage vector and the counter electromotive force vector of the motor winding aiming at the characteristic that the external variable frequency driver cannot directly detect the rotation condition of the motor rotor and the fluctuation of the sampling value of the phase current of the motor winding, the problem that the external variable frequency driver is difficult to detect the motor stalling is solved, the capacity of the external driver for identifying the motor stalling state is improved, the running reliability of the external variable frequency driver is improved, and the use sensitivity of a user is improved.
The methods and systems of the present disclosure may be implemented in a number of ways. For example, the methods and systems of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order for the steps of the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above unless specifically stated otherwise. Further, in some embodiments, the present disclosure may also be embodied as programs recorded in a recording medium, the programs including machine-readable instructions for implementing the methods according to the present disclosure. Thus, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.
The description of the present disclosure has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to practitioners skilled in this art. The embodiment was chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.

Claims (21)

1. A motor locked-rotor detection method is applied to an external variable frequency driver, wherein the external variable frequency driver comprises: a state observer and a magnetic field vector orientation controller; the method comprises the following steps:
acquiring a back electromotive force voltage frequency value determined by the state observer; the state observer acquires the current value of a three-phase winding of the motor in real time, and determines the counter electromotive voltage frequency value according to the current value of the three-phase winding;
judging whether the counter electromotive force voltage frequency value is smaller than a counter electromotive force voltage frequency threshold value or not;
and if so, determining that the motor has a locked-rotor fault.
2. The method of claim 1, further comprising:
and if the counter electromotive voltage frequency value is greater than or equal to the counter electromotive voltage frequency threshold value, determining a first effective value of a counter electromotive voltage vector modulus value corresponding to the motor and a second effective value of a stator winding phase voltage vector modulus value, and judging whether the motor has a locked-rotor fault or not based on a comparison relation between the first effective value and the second effective value.
3. The method of claim 2, wherein the determining whether the locked-rotor fault has occurred to the motor based on the comparison between the first effective value and the second effective value comprises:
and if the first effective value is larger than the second effective value, determining that the motor has a locked-rotor fault.
4. The method of claim 2 or 3, wherein the magnetic field vector orientation controller generates PWM control signals for controlling the motor; the determining a first effective value of a back-emf voltage vector norm value corresponding to the motor comprises:
acquiring a d-axis counter electromotive voltage value and a q-axis counter electromotive voltage value determined by the state observer; wherein the state observer determines the d-axis back electromotive force voltage value and the q-axis back electromotive force voltage value based on a current value of the three-phase winding;
obtaining a first period value of the PWM control signal and a second period value corresponding to the counter electromotive force voltage frequency value;
calculating the first effective value based on the d-axis back electromotive force voltage value, the q-axis back electromotive force voltage value, the first period value, and the second period value.
5. The method of claim 4, the calculating the first valid value based on the d-axis back-EMF voltage value, the q-axis back-EMF voltage value, the first period value, and the second period value comprising:
calculating the square sum of the d-axis back electromotive force voltage value and the q-axis back electromotive force voltage value, and determining a first numerical value corresponding to the back electromotive force voltage;
determining an accumulated value of the first numerical value based on the first numerical value and the first periodic value;
and calculating the quotient of the accumulated value of the first numerical value and the second period value, and taking the square root of the quotient as the first effective value.
6. The method of claim 4, the determining a second effective value of a stator winding phase voltage vector magnitude corresponding to the electric machine comprising:
acquiring a d-axis voltage value and a q-axis voltage value determined by the magnetic field vector orientation controller;
wherein the state observer determines a d-axis stator current value and a q-axis stator current value based on current values of the three-phase winding; the magnetic field vector orientation controller processes based on the d-axis stator current value and the q-axis stator current value to obtain a d-axis voltage value and a q-axis voltage value for controlling the motor;
calculating the second effective value based on the d-axis voltage value, the q-axis voltage value, the first period value, and the second period value.
7. The method of claim 6, the calculating the second valid value based on the d-axis voltage value, the q-axis voltage value, the first period value, and the second period value comprising:
calculating the square sum of the d-axis voltage value and the q-axis voltage value, and determining a second value corresponding to the stator winding phase voltage;
determining an accumulated value of the second numerical value based on the second numerical value and the first periodic value;
and calculating the quotient of the accumulated value of the second numerical value and the second period value, and taking the square root of the quotient as the second effective value.
8. The method of claim 1, further comprising:
and under the condition that the state of the motor is determined to be normal and a starting instruction is received, acquiring a counter electromotive force voltage frequency value determined by the state observer.
9. The method of claim 1, further comprising:
and under the condition that the motor is judged to have a locked-rotor fault, controlling the motor to stop running through the magnetic field vector orientation controller.
10. The utility model provides a motor stalling detection device, is applied to external variable frequency drive, wherein, external variable frequency drive includes: a state observer and a magnetic field vector orientation controller; the motor locked rotor detection device comprises:
the frequency value acquisition module is used for acquiring a back electromotive force voltage frequency value determined by the state observer; the state observer acquires the current value of a three-phase winding of the motor in real time, and determines the counter electromotive voltage frequency value according to the current value of the three-phase winding;
the frequency value judging module is used for judging whether the counter electromotive voltage frequency value is smaller than a counter electromotive voltage frequency threshold value;
a first fault determination module configured to determine that a locked-rotor fault occurs in the motor if the back electromotive voltage frequency value is less than a back electromotive voltage frequency threshold.
11. The apparatus of claim 10, comprising:
and the second fault determination module is used for determining a first effective value of a back electromotive voltage vector modulus value corresponding to the motor and a second effective value of a stator winding phase voltage vector modulus value if the back electromotive voltage frequency value is greater than or equal to the back electromotive voltage frequency threshold value, and judging whether the motor has a locked-rotor fault or not based on a comparison relation between the first effective value and the second effective value.
12. The apparatus of claim 11, wherein,
the second fault determination module includes:
and the locked-rotor fault determining unit is used for determining that the locked-rotor fault occurs in the motor if the first effective value is greater than the second effective value.
13. The apparatus of claim 11 or 12, wherein the magnetic field vector orientation controller generates PWM control signals for controlling a motor;
the second fault determination module includes:
the first data acquisition unit is used for acquiring the d-axis counter electromotive voltage value and the q-axis counter electromotive voltage value determined by the state observer; wherein the state observer determines the d-axis back electromotive force voltage value and the q-axis back electromotive force voltage value based on a current value of the three-phase winding; obtaining a first period value of the PWM control signal and a second period value corresponding to the back electromotive force voltage frequency value;
a first calculation unit to calculate the first effective value based on the d-axis back electromotive force voltage value, the q-axis back electromotive force voltage value, the first period value, and the second period value.
14. The apparatus of claim 13, wherein,
the first calculating unit is specifically configured to calculate a sum of squares of the d-axis back electromotive voltage value and the q-axis back electromotive voltage value, and determine a first numerical value corresponding to the back electromotive voltage; determining an accumulated value of the first numerical value based on the first numerical value and the first periodic value; and calculating the quotient of the accumulated value of the first numerical value and the second period value, and taking the square root of the quotient as the first effective value.
15. The apparatus of claim 13, wherein,
the second fault determination module includes:
a second data acquisition unit for acquiring the d-axis voltage value and the q-axis voltage value determined by the magnetic field vector orientation controller; wherein the state observer determines a d-axis stator current value and a q-axis stator current value based on current values of the three-phase winding; the magnetic field vector orientation controller processes based on the d-axis stator current value and the q-axis stator current value to obtain a d-axis voltage value and a q-axis voltage value for controlling the motor;
a second calculation unit to calculate the second effective value based on the d-axis voltage value, the q-axis voltage value, the first period value, and the second period value.
16. The apparatus of claim 15, wherein,
the second calculating unit is specifically configured to calculate a sum of squares of the d-axis voltage value and the q-axis voltage value, and determine a second value corresponding to the stator winding phase voltage; determining an accumulated value of the second numerical value based on the second numerical value and the first periodic value; and calculating the quotient of the accumulated value of the second numerical value and the second period value, and taking the square root of the quotient as the second effective value.
17. The apparatus of claim 10, wherein,
the frequency value acquisition module is used for acquiring the back electromotive force voltage frequency value determined by the state observer under the condition that the state of the motor is determined to be normal and a starting instruction is received.
18. The apparatus of claim 10, further comprising:
and the fault processing module is used for controlling the motor to stop running through the magnetic field vector orientation controller under the condition of judging that the motor has a locked-rotor fault.
19. A motor stall detection apparatus comprising:
a memory; and a processor coupled to the memory, the processor configured to perform the method of any of claims 1-9 based on instructions stored in the memory.
20. An external variable frequency drive comprising:
the motor stall detection apparatus of any of claims 10 to 19.
21. A computer-readable storage medium having stored thereon computer instructions for execution by a processor to perform the method of any one of claims 1 to 9.
CN202210438400.5A 2022-04-25 2022-04-25 Motor locked-rotor detection method and device, external variable frequency driver and medium Pending CN114814575A (en)

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CN202210438400.5A CN114814575A (en) 2022-04-25 2022-04-25 Motor locked-rotor detection method and device, external variable frequency driver and medium

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