CN114487911A - On-line detection method and device for turn-to-turn short circuit fault, motor and operation machine - Google Patents
On-line detection method and device for turn-to-turn short circuit fault, motor and operation machine Download PDFInfo
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- CN114487911A CN114487911A CN202210108402.8A CN202210108402A CN114487911A CN 114487911 A CN114487911 A CN 114487911A CN 202210108402 A CN202210108402 A CN 202210108402A CN 114487911 A CN114487911 A CN 114487911A
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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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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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
- G01R31/346—Testing of armature or field windings
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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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/72—Testing of electric windings
Abstract
The invention provides an on-line detection method and device for turn-to-turn short circuit faults, a motor and an operating machine, wherein the method comprises the following steps: acquiring a three-phase stator current signal of a motor to be tested at the current rotating speed based on double closed-loop control; extracting characteristic harmonic waves related to turn-to-turn short circuit in the three-phase stator current signals to serve as fault detection signals; and determining the running state of the motor to be detected according to the characteristic frequency information of the fault detection signal. The inter-turn short circuit fault on-line detection method, the inter-turn short circuit fault on-line detection device, the motor and the operation machinery provided by the invention can be used for carrying out on-line monitoring on the inter-turn short circuit fault of the permanent magnet motor under the control of the double closed loops, can effectively distinguish whether the fault phenomenon of the permanent magnet motor is caused by the early-occurring inter-turn short circuit, and have high detection precision.
Description
Technical Field
The invention relates to the technical field of mechanical fault diagnosis, in particular to an on-line detection method and device for turn-to-turn short circuit faults, a motor and an operating machine.
Background
At present, there are many ways to diagnose turn-to-turn short circuit fault of permanent magnet synchronous motor for electric vehicle, for example: extracting fault characteristics of the permanent magnet synchronous motor by using an improved Empirical Mode Decomposition (EMD) algorithm, and comparing the fault characteristics with normal parameters; fault detection for PMSM by wavelet analysis method and turn-to-turn short circuit fault detection for permanent magnet synchronous motor by deep learning method
Through analysis of the prior art, the existing diagnosis of the turn-to-turn short circuit fault of the permanent magnet synchronous motor is basically off-line detection, and the stator current of the fault detected by different methods is compared with the stator current under normal conditions, so that the validity of the respective methods is verified.
However, in actual work, a vehicle owner cannot frequently maintain and overhaul the motor, if the motor has turn-to-turn short circuit fault in the early stage, the motor cannot be diagnosed in time, and potential and huge potential safety hazards are formed for driving safety.
Disclosure of Invention
The invention provides a turn-to-turn short circuit fault on-line detection method and device, a motor and an operation machine, which are used for solving the problem that the early-stage turn-to-turn short circuit fault cannot be timely found by comparing extracted stator current with stator current under normal conditions in an off-line state in the prior art, and realizing the on-line detection of the turn-to-turn short circuit fault of a permanent magnet synchronous motor for a vehicle.
In a first aspect, the present invention provides a method for detecting turn-to-turn short circuit fault of a motor, including:
acquiring a three-phase stator current signal of a motor to be tested at the current rotating speed based on double closed-loop control;
extracting characteristic harmonic waves related to turn-to-turn short circuit in the three-phase stator current signals to serve as fault detection signals;
and determining the running state of the motor to be detected according to the characteristic frequency information of the fault detection signal.
According to the method for detecting the turn-to-turn short circuit fault of the motor, provided by the invention, the extraction of the characteristic harmonic related to the turn-to-turn short circuit in the three-phase stator current signal comprises the following steps:
extracting characteristic harmonic components related to turn-to-turn short circuit from the three-phase stator current signals by using a Kalman filter in a Matlab VibraTools toolbox;
and acquiring an amplitude envelope curve of the characteristic harmonic component to use the amplitude envelope curve as the characteristic harmonic.
According to the method for detecting the turn-to-turn short circuit fault of the motor, the harmonic signal related to the turn-to-turn short circuit is a third harmonic signal and/or a fifth harmonic signal.
According to the turn-to-turn short circuit fault detection method for the motor, the operation state of the motor to be detected is determined according to the characteristic frequency information of the fault detection signal, and the method comprises the following steps:
calling a stator current wavelet decomposition frequency band coefficient energy list of the motor to be detected under the conditions that the current rotating speed of the motor to be detected and the stator winding of the motor to be detected have turn-to-turn short circuit faults of different degrees;
determining a target frequency band where the fundamental frequency of the characteristic harmonic is located in a characteristic frequency reference table;
and selecting the energy of the target frequency band as the characteristic frequency information of the fault detection signal, and determining the running state of the motor to be detected according to the energy of the target frequency band.
According to the turn-to-turn short circuit fault detection method for the motor, the operation state of the motor to be detected is determined according to the characteristic frequency information of the fault detection signal, and the method comprises the following steps:
calculating the root mean square value of the energy of the target frequency band according to the characteristic frequency information of the fault detection signal, and taking the root mean square value as a detection root mean square value;
acquiring a root mean square value of sub-band coefficient energy of each characteristic frequency of a target motor in a normal state as a standard root mean square value;
determining a fault detection value according to the detection root mean square value and the standard root mean square value;
and determining the running state of the motor to be detected according to the size of the fault detection value.
According to the turn-to-turn short circuit fault detection method for the motor, provided by the invention, the function expression of the fault detection value is determined according to the detection root mean square value and the standard root mean square value as follows:
wherein E is a detection root mean square value; e0Is a standard root mean square value; and S is a fault detection value.
According to the turn-to-turn short circuit fault detection method for the motor, before the operation state of the motor to be detected is determined according to the characteristic frequency information of the fault detection signal, the method comprises the following steps:
simulating three-phase stator current signals of the motor to be tested under various operating conditions;
and decomposing each three-phase stator current signal, calculating the energy root mean square of each sub-band coefficient, and constructing a stator current wavelet decomposition band coefficient energy list set under different working conditions.
In a second aspect, the present invention further provides a motor turn-to-turn short circuit fault detection apparatus, including:
the signal acquisition unit is used for acquiring a three-phase stator current signal of the motor to be detected at the current rotating speed based on double closed-loop control;
the signal extraction unit is used for extracting characteristic harmonic waves related to turn-to-turn short circuit in the three-phase stator current signals and using the characteristic harmonic waves as fault detection signals;
and the state operation unit is used for determining the running state of the motor to be detected according to the characteristic frequency information of the fault detection signal.
In a third aspect, the present invention also provides an electric machine comprising: the motor comprises a motor body, wherein a current signal acquisition module and a rotating speed acquisition module are arranged on the motor body, the current signal acquisition module is used for acquiring three-phase stator current signals when the motor runs in real time, and the rotating speed acquisition module is used for acquiring the current rotating speed of the motor;
the data sending unit is used for sending the current rotating speed and the three-phase stator current signals to the online detection processor;
the online detection processor comprises a memory and a program or an instruction which is stored on the memory and can be operated on the online detection processor, and when the program or the instruction is executed by the online detection processor, the steps of any one of the motor turn-to-turn short circuit fault detection methods are executed.
In a fourth aspect, the present invention also provides a working machine in which the above-described motor is disposed.
In a fifth aspect, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the motor turn-to-turn short circuit fault detection method according to any one of the above methods.
In a sixth aspect, the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program, when being executed by a processor, implementing the steps of the motor turn-to-turn short circuit fault detection method according to any one of the above.
According to the inter-turn short circuit fault online detection method, the inter-turn short circuit fault online detection device, the motor and the operation machine, the characteristic harmonic of three-phase constant-value current of the motor under closed-loop control is extracted, the characteristic harmonic is converted into a fault detection value according to the related frequency band energy of the characteristic harmonic, the running state of the motor to be detected is judged according to the size of the fault detection value, the inter-turn short circuit fault of the permanent magnet motor under double closed-loop control can be monitored online, whether the fault phenomenon of the permanent magnet motor is caused by the early-occurring inter-turn short circuit can be effectively distinguished, and the detection precision is high.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a schematic flow chart of a motor turn-to-turn short circuit fault detection method provided by the present invention;
FIG. 2 is a winding circuit diagram of a PMSM with a turn-to-turn short circuit;
FIG. 3 is a schematic diagram of the current loop control principle of the PMSM control system;
FIG. 4 is a schematic diagram of the speed loop control principle of the PMSM control system;
FIG. 3 is a schematic flow chart for obtaining an odometry feature table and a trajectory routing graph according to the present invention;
FIG. 4 is a schematic flow chart of the present invention for obtaining information about obstacles in front of a train;
FIG. 5 is a diagram of a table of energy of wavelet decomposition band coefficients of a stator current provided by the present invention;
FIG. 6 is a schematic structural diagram of a turn-to-turn short circuit fault detection device of a motor according to the present invention;
fig. 7 is a schematic structural diagram of an electronic device provided by the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that in the description of the embodiments of the present invention, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element. The terms "upper", "lower", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The terms first, second and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that embodiments of the application may be practiced in sequences other than those illustrated or described herein, and that the terms "first," "second," and the like are generally used herein in a generic sense and do not limit the number of terms, e.g., the first term can be one or more than one. In addition, "and/or" in the specification and claims means at least one of connected objects, a character "/" generally means that a preceding and succeeding related objects are in an "or" relationship.
A Permanent Magnet Synchronous Motor (PMSM) is an optimal choice for a motor for an electric vehicle because of its performance advantages of small size, light weight, high efficiency, reliable operation, low noise, etc. However, the electric vehicle is in a driving background such as starting, accelerating, decelerating, braking and the like for a long time, and the driving environment is diversified, such as dust, water mist and the like, so that the vehicle motor is exposed to the environments such as vibration, over-high temperature, over-low temperature or humidity, and the factors can cause the inter-turn short circuit fault of the motor, thereby affecting the safe operation of the vehicle motor, and therefore, the method has very important practical significance for diagnosing the inter-turn short circuit fault of the vehicle permanent magnet synchronous motor.
At present, there are many ways of diagnosing turn-to-turn short circuit faults of permanent magnet synchronous motors, especially vehicle-mounted PMSM, for example:
However, in the above prior art, the inter-turn short circuit fault diagnosis in the PMSM all adopts an off-line detection method, and compares the stator current at the time of the fault detected in different methods with the stator current in a normal condition, so as to obtain the occurrence condition of the inter-turn short circuit fault. If the motor has turn-to-turn short circuit fault in the early stage, the motor cannot be diagnosed in time, and potential and huge potential safety hazard is formed to driving safety.
In conclusion, if the PMSM is subjected to online detection, the damage degree of the motor can be greatly reduced, and the occurrence of a serious traffic accident can be avoided.
The following describes a turn-to-turn short circuit fault online detection method, device, motor and working machine provided by the embodiment of the invention with reference to fig. 1 to 6.
Fig. 1 is a schematic flow chart of a motor turn-to-turn short circuit fault detection method provided by the present invention, as shown in fig. 1, including but not limited to the following steps:
step 101: acquiring a three-phase stator current signal of a motor to be tested at the current rotating speed based on double closed-loop control;
step 102: extracting characteristic harmonic waves related to turn-to-turn short circuit in the three-phase stator current signals to serve as fault detection signals;
step 103: and determining the running state of the motor to be detected according to the characteristic frequency information of the fault detection signal.
In practical application, in step 101, a current sensor, a voltage sensor, and other related sensors may be added to the vehicle-mounted PMSM in advance, so as to collect a three-phase stator current Signal of the motor in real time, transmit the collected value to a Digital Signal Processing (DSP), perform analog-to-Digital conversion, and transmit the converted value to an upper computer through a bus Signal.
Because the PMSM has a fault and the fault phenomenon is diversified, for example, when the PMSM has a turn-to-turn short circuit fault, the phenomena of motor jitter, short-circuit phase current increase, heat generation and the like can occur, but the fault phenomenon of the motor jitter and the like can also be caused by a mechanical fault, such as a bearing fault. Therefore, in order to determine whether the fault phenomenon is caused by turn-to-turn short circuit, the invention can analyze the characteristic harmonic (such as third harmonic, fifth harmonic and the like) related to the turn-to-turn short circuit in the three-phase stator current signal by adopting a wavelet analysis method or a neural network and the like, thereby determining the occurrence of PMSM turn-to-turn short circuit fault.
In step 102, the extracted characteristic harmonics can be used as fault detection signals by extracting characteristic harmonics (typically odd harmonics such as third harmonic and fifth harmonic) related to turn-to-turn short circuit in the three-phase stator current signals.
Further, in step 103, the fault may be monitored and the fault degree may be determined according to that the amplitude of the third harmonic of the short-circuit phase current when the turn-to-turn short-circuit fault occurs is much larger than the amplitudes of the third harmonics of the other two phases (or normal phases).
For example: the operating state of the motor to be tested is determined by extracting the characteristic frequency information of the third harmonic of the current, for example, extracting the slope of the change curve of the amplitude of the third harmonic along with the current rotating speed as the characteristic frequency information, and according to the slope, the operating state of the motor to be tested is determined, including the judgment of the occurrence and severity of turn-to-turn short circuit faults.
According to the on-line detection method for the turn-to-turn short circuit fault, the characteristic harmonic of the three-phase constant-value current of the motor under closed-loop control is extracted, the characteristic harmonic is converted into the fault detection value according to the related frequency band energy of the characteristic harmonic, the running state of the motor to be detected is judged according to the size of the fault detection value, the on-line monitoring can be carried out on the turn-to-turn short circuit fault of the permanent magnet motor under double closed-loop control, whether the fault phenomenon of the permanent magnet motor is caused by the turn-to-turn short circuit can be effectively distinguished, and the detection precision is high.
It should be noted that, the invention can realize on-line detection because the acquisition of the three-phase stator current signal can be carried out on line; meanwhile, the double closed loop is used for detecting the turn-to-turn short circuit fault under the double closed loop, and the double closed loop is used for simulating the environment of the motor in actual operation, so that once the motor has the turn-to-turn short circuit fault, the fault can be timely found according to the collected characteristic harmonic waves related to the turn-to-turn short circuit, and the defect that the fault can be judged only by disassembling the motor after the motor is completely burnt out and cannot be operated in the prior art is overcome.
The method for detecting the turn-to-turn short circuit fault of the motor can realize real-time monitoring of the early turn-to-turn short circuit fault of the motor, so that a relevant coping strategy can be made for the motor fault in time, and other interlocking accidents caused by the motor fault are avoided.
Based on the content of the foregoing embodiments, as an alternative embodiment, the extracting the characteristic harmonic related to the turn-to-turn short circuit in the three-phase stator current signal set forth in step 102 may include, but is not limited to, the following steps: extracting characteristic harmonic components related to turn-to-turn short circuit from the three-phase stator current signals by using a Kalman filter in a Matlab VibraTools toolbox; and acquiring an amplitude envelope curve of the characteristic harmonic component to use the amplitude envelope curve as the characteristic harmonic.
As an alternative embodiment, the harmonic signal related to the turn-to-turn short circuit is a third harmonic signal and/or a fifth harmonic signal.
Generally, a pulsating magnetic field formed by the short-circuit current induces a magnetomotive force rotating in the opposite direction in the three-phase winding of the motor, so that the three-phase current is unbalanced. When the PMSM has turn-to-turn short circuit fault, the motor formed by the PMSM is unbalanced, and odd harmonic components, especially third harmonic components and fifth harmonic components, appearing on the current spectrum of the short-circuit current phase are obvious characteristic harmonic components. Taking this characteristic into account, the present invention determines the characteristic harmonics as the third and/or fifth harmonics of the three-phase stator current signal.
Specifically, the characteristic harmonic related to turn-to-turn short circuit in the three-phase stator current information can be respectively extracted based on a Kalman order tracking algorithm (VKF-OT algorithm for short) under the conditions that a current loop and a rotating speed loop of the PMSM are respectively under open-loop control and closed-loop control.
The open-loop control and closed-loop control condition refers to that the current loop and the rotating speed loop of the motor are respectively controlled in an open-loop mode and a closed-loop mode. The method specifically comprises the following steps: and performing open-loop and closed-loop simulation on the current inner ring. And then taking the current closed loop as a whole as a link of the rotating speed outer loop, and performing open loop and closed loop simulation on the rotating speed outer loop.
The invention aims to research the PMSM current loop and the PMSM rotating speed loop under the conditions of open-loop control and closed-loop control respectively:
1) splitting the double closed loops of the motor, and analyzing the influence of faults on a motor control system in detail;
2) the detection under the open loop, namely the current commonly used fault detection method, is compared with the simulation result under the closed loop control, so that the difference of the fault phenomenon and the feasibility of the fault detection under the closed loop control can be displayed.
The step ratio tracking is to separate a step ratio signal (namely, a characteristic harmonic) related to turn-to-turn short circuit from a given three-phase stator current signal, and can eliminate interference caused by rotation speed fluctuation. It should be noted that the three-phase stator current signal usually includes multiple harmonic and noise signals.
The VKF-OT algorithm provided by the invention is an order tracking algorithm based on a Kalman filter, and can directly extract the amplitude and phase of the target characteristic harmonic by directly acting on the time domain of a three-phase stator current signal.
The invocation of the kalman filter can be found in the vibralools toolbox of Matlab.
Optionally, according to the established PMSM mathematical model, an i-adopted simulation platform is established in a Matlab/Simulink simulation platformdThe vector control simulation diagram is 0 and comprises a Park conversion module, an SVPWM module and a PMSM module with turn-to-turn short circuit fault information.
The amplitude of the third harmonic component of the phase current of the motor short circuit is increased along with the deepening of turn-to-turn short circuit fault, and is also increased along with the increasing of the rotating speed.
In order to research the change condition of the short-circuit current of the motor along with the current rotating speed and better understand the innovation of extracting the characteristic harmonic wave by adopting a VKF-OT algorithm and carrying out the judgment basis of the turn-to-turn short-circuit fault of the motor according to the characteristic frequency information of the characteristic harmonic wave, the following description is made:
in the case of a turn-to-turn short circuit of the motor, the voltage drop expression of the short-circuit sub-branch shown in fig. 2 is:
because the motor permanent magnet has induction effect, only the last left term in the voltage drop expression is considered, and the short-circuit current of the short-circuit branch circuit
Can be expressed as:
wherein the content of the first and second substances,Vfis the short circuit branch voltage drop; i isfIs short circuit branch current; rsThe resistance is a three-phase winding resistance of the motor; sigma is the turn-to-turn short circuit fault degree of the motor; Ψ is a flux linkage.
Because the amplitude of the short-circuit current is approximately linear with the current rotating speed at a certain time of turn-to-turn short-circuit fault. With the increase of the current rotating speed, the short-circuit current is usually not measurable, so that the short-circuit current cannot be simply used as the characteristic information of the turn-to-turn short-circuit fault detection of the motor.
In view of this, after the characteristic harmonic component (such as a third harmonic component) related to the turn-to-turn short circuit in the three-phase stator current signal is extracted by using the VKF-OT algorithm, an amplitude envelope curve of the extracted third harmonic component may be further extracted by using a peak detection algorithm and the like, and the amplitude envelope curve is used as a fault detection signal. The amplitude envelope curve of the third harmonic component changes correspondingly with the degree of turn-to-turn short circuit fault and the current rotating speed change condition, and the running state of the motor to be tested can be reflected really.
The extraction of the amplitude envelope curve of the third harmonic (or the fifth harmonic) in the three-phase stator current signal through the VKF-OT algorithm can only judge whether the inter-turn short circuit fault occurs in the motor, but cannot accurately judge the actual position of the inter-turn short circuit fault in the fault phase and the severity of the inter-turn short circuit.
The method determines the running state of the motor to be detected according to the characteristic frequency information of the fault detection signal, and specifically comprises the following steps of:
calling a stator current wavelet decomposition frequency band coefficient energy list of the motor to be detected under the conditions that the current rotating speed of the motor to be detected and the stator winding of the motor to be detected have turn-to-turn short circuit faults of different degrees;
determining a target frequency band where the fundamental frequency of the characteristic harmonic is located in a characteristic frequency reference table;
and selecting the energy of the target frequency band as the characteristic frequency information of the fault detection signal, and determining the running state of the motor to be detected according to the energy of the target frequency band.
And determining the running state of the motor to be tested comprises judging whether the motor to be tested has turn-to-turn short circuit fault, the position of the turn-to-turn short circuit fault in a fault phase and the severity of the turn-to-turn short circuit fault.
Firstly, in the case of a turn-to-turn short circuit of the motor, the characteristic frequency of the turn-to-turn short circuit fault of the stator winding is constant when the motor operates at different rotating speeds.
For example, when the rotating speed of the motor is 1000 r/rad-6000 r/rad, the characteristic frequency of the short circuit fault between the stator winding turns is 150-2700 HZ.
In order to effectively determine the actual condition of the turn-to-turn short circuit fault, the invention extracts the frequency band coefficient energy containing the characteristic frequency in the characteristic harmonic wave as the characteristic frequency information (which can also be understood as a characteristic vector) of the fault detection by using a wavelet analysis method.
Firstly, the sampling time can be set to be 0.12s, the sampling frequency is 6000HZ, the number of sampling points is 720, and db4 wavelet is selected as a basis function to perform wavelet analysis on the fault detection signal within the analysis frequency range (150-2700 HZ) of the fault detection signal, so as to obtain the corresponding fundamental frequency.
After the fundamental wave frequency of the fault detection signal of the motor to be detected is determined, the sub-band (recorded as the nth sub-band) where the fundamental wave frequency is located is determined according to the stator current wavelet decomposition frequency band coefficient energy list under the condition that the stator winding has the turn-to-turn short circuit faults of different degrees, and then the characteristic frequency of the stator current can be calculated according to the functional relation between the characteristic frequency of the stator current and the rotating speed frequency of the motor.
The functional relation between the characteristic frequency of the stator current and the rotating speed frequency of the motor is as follows:
Ff＝((2n±1)p)Fs；
wherein, FfThe characteristic frequency of the turn-to-turn short circuit fault of the winding is obtained; fsThe rotating speed frequency of the motor is shown, and p is the pole pair number.
As an alternative embodiment, the method for determining the operating state of the motor to be tested according to the characteristic frequency information of the fault detection signal mainly includes the following steps:
calculating the root mean square value of the energy of the target frequency band according to the characteristic frequency information of the fault detection signal, and taking the root mean square value as a detection root mean square value;
acquiring a root mean square value of sub-band coefficient energy of each characteristic frequency of a target motor in a normal state as a standard root mean square value;
determining a fault detection value according to the detection root mean square value and the standard root mean square value;
and determining the running state of the motor to be detected according to the size of the fault detection value.
Wherein the functional expression of the fault detection value is:
e is a detected root mean square value; e0Is a standard root mean square value; and S is a fault detection value.
Specifically, in order to quantify the amplitude and distribution of the amplitude envelope curve of the extracted sign harmonic component, on one hand, the position of the inter-turn short-circuit fault occurring in the fault phase is determined by the sub-band where the characteristic frequency of the sign inter-turn short-circuit fault is located at the current rotating speed; on the other hand, the degree of turn-to-turn short circuit fault is specifically represented by calculating the root mean square of the wavelet signal sub-band coefficient energy related to the target frequency band where the characteristic frequency information is located, and finally quantizing the root mean square into a fault detection value.
When the current rotating speed of the motor is 2000r/min, the sub-frequency bands where the characteristic frequency representing the turn-to-turn short circuit fault of the motor is located are D1, D2 and D4 sub-frequency bands, and the position of the turn-to-turn short circuit fault can be located according to the distribution of the sub-frequency bands.
Further, a standard root mean square value can be calculated according to the calculated root mean square value of the sub-band where the characteristic frequency is located, and the root mean square value of the coefficient energy of the sub-band of each characteristic frequency in a normal state is calculated to be used as the standard root mean square value; and calculating the fault detection value of the target point at the current rotating speed by adopting the fault detection value calculation formula. And then classifying the fault degree according to the size of the fault detection value.
For example: when the fault detection value is below 0-5%, the motor is considered to be normal; when the fault detection value is 5% -8%, the motor is considered to have slight turn-to-turn short circuit; when the fault detection value is 8% -15%, the motor is considered to have serious turn-to-turn short circuit; and when the fault detection value is more than 15%, the motor is considered to be damaged.
Based on the content of the foregoing embodiment, as an optional embodiment, before determining the operating state of the motor to be tested according to the characteristic frequency information of the fault detection signal, the method includes: simulating three-phase stator current signals of the motor to be tested under various operating conditions; and decomposing each three-phase stator current signal, calculating the energy root mean square of each sub-band coefficient, and constructing a stator current wavelet decomposition band coefficient energy list set under different working conditions.
Fig. 5 is a schematic diagram of a stator current wavelet decomposition band coefficient energy list, according to the present invention, under an experimental condition, by respectively maintaining the rotation speed of a target motor at 1000r/min and 4300r/min, by simulating the inter-turn short circuit fault condition at different positions of a fault phase of the target motor, and actually recording the characteristic frequency of the inter-turn short circuit fault of a stator winding when the fault motor operates at two rotation speeds, and in order to effectively analyze the fault frequency thereof, extracting the band coefficient energy containing the characteristic frequency as a fault detection characteristic vector by using a wavelet analysis method, and making the stator current wavelet decomposition band coefficient energy list shown in fig. 5.
Alternatively, the stator current wavelet decomposition band coefficient energy list may be provided by the motor manufacturer.
Fig. 6 is a schematic structural diagram of the motor turn-to-turn short circuit fault detection apparatus of the present invention, as shown in fig. 6, mainly including a signal acquisition unit 61, a signal extraction unit 62, and a state operation unit 63, wherein:
the signal acquisition unit 61 is mainly used for acquiring a three-phase stator current signal of the motor to be detected at the current rotating speed based on double closed-loop control;
a signal extraction unit 62, configured to extract a characteristic harmonic related to a turn-to-turn short circuit in the three-phase stator current signal as a fault detection signal;
and a state operation unit 63, configured to determine an operating state of the motor to be tested according to the characteristic frequency information of the fault detection signal.
It should be noted that, when the motor turn-to-turn short circuit fault detection apparatus provided in the embodiment of the present invention is in specific operation, the motor turn-to-turn short circuit fault detection method described in any of the above embodiments may be executed, which is not described in detail in this embodiment.
According to the motor turn-to-turn short circuit fault detection method provided by the invention, the characteristic harmonic of three-phase constant-value current of the motor under closed-loop control is extracted, the characteristic harmonic is converted into a fault detection value according to the related frequency band energy of the characteristic harmonic, the running state of the motor to be detected is judged according to the size of the fault detection value, the turn-to-turn short circuit fault of the permanent magnet motor under double closed-loop control can be monitored on line, whether the fault phenomenon of the permanent magnet motor is caused by the early turn-to-turn short circuit can be effectively distinguished, and the detection precision is high.
Further, the present invention provides a motor, which mainly comprises: the motor comprises a motor body, wherein a current signal acquisition module and a rotating speed acquisition module are arranged on the motor body, the current signal acquisition module is used for acquiring three-phase stator current signals when the motor runs in real time, and the rotating speed acquisition module is used for acquiring the current rotating speed of the motor.
The motor also comprises a data sending unit which is used for sending the current rotating speed and the three-phase stator current signals to an online detection processor; the on-line detection processor comprises a memory and a program or an instruction which is stored on the memory and can be run on the on-line detection processor, and when the program or the instruction is executed by the on-line detection processor, the steps of the motor turn-to-turn short circuit fault detection method provided by any one of the above embodiments are executed.
Furthermore, the invention also provides a working machine, and the motor is arranged on the working machine.
After the online detection method for the PMSM provided by the invention is introduced in detail, the invention further theoretically explains the principle and the inventive idea of the specific technical means adopted for realizing the invention:
(1) when a PMSM (permanent magnet synchronous motor) mathematical model with turn-to-turn short circuit fault is built, two fault parameters u and R are introducedf. Where u is called the turn-to-turn short-circuit ratio and is the number of short-circuit turns N of the short-circuit phasefAnd the total number of turns NsCan be expressed as u-Nf/NsThe parameter ranges from 0 to 1, and the closer to 1, the greater the degree of turn-to-turn short circuit failure. As shown in fig. 2, when u is 0, it indicates that the PMSM is in a normal operating state; when u ≠ 0, it indicates that the PMSM is in a turn-to-turn short circuit fault state.
(2) And deducing transfer functions of the PMSM under an open loop and a closed loop respectively.
Open loop transfer function G of PMSMi(s)oThe expression of (a) is:
wherein, TsSampling time for a current loop; l isqIs a motor q-axis inductor; r is a three-phase resistance value; and s is a control theory transfer function.
Closed loop transfer function G of PMSMi(s)cThe expression of (a) is:
h is an expression of a feedback channel in a control theory transfer function; kg＝2Kp/3LqTs。
The transfer function is analyzed from the frequency domain, so that the open-loop cut-off frequency of the PMSM control system, the closed-loop bandwidth frequency and the variation range thereof can be deduced, and the cut-off frequency relation corresponding to the open-loop and closed-loop control of the PMSM under the normal and fault conditions is observed by means of the bode diagram.
In the following, briefly described, the above-mentioned open-loop transfer function Gi(s)oAnd closed loop transfer function Gi(s)cThe specific derivation process of (1):
the transfer function is derived from fig. 3 and 4:
1) in the case of open loop of the current loop, the open loop transfer function G of the PMSMi(s)oCan be converted into:
wherein, KPWMThe gain parameter of PWM can be regarded as a constant, and the gain parameter can be regarded as 1 to simplify the processing, so that the open-loop transfer function G can be obtainedi(s)o：
Then omegacFor the current loop open loop cutoff frequency, the expression may be:
wherein, TsSampling time for current loop, WcFor open loop cut-off frequency, LqIs the Q-axis inductance value.
2) Closed loop transfer function G of PMSM under condition of closed loop of current loopi(s)cThe expression of (a) is:
H＝1；
wherein, KpIs the gain parameter of the PI controller.
Comparing it with typical motor control system, the current loop controller K can be calculatedp、KiThe values of (d) are expressed as:
wherein, KiFor the gain parameter of PI control, RsAnd (4) resistance of a three-phase winding of the motor.
Current loop controller Kp、KiRespectively substituting the values of (A) into the closed loop transfer function G of the medium to PMSMi(s)cThen, the closed loop transfer function of the current loop system can be obtained as follows:
the cut-off frequency of the current loop closed loop transfer function can be determined to be omegabThe expression of (a) is:
wherein, G'i(jωb)oRepresenting the current loop closed loop transfer function.
3) In the case of an open speed loop, the open speed loop transfer function G of the PMSMn(s)oThe expression of (a) is:
wherein, TdIs the current filter time constant; pnIs the number of pole pairs of the motor; psi is the motor flux linkage; j is the moment of inertia of the motor.
By simplifying it, we can get:
wherein, KnIs an intermediate variable used to simplify the function of the formula. .
The open-loop cut-off frequency omega can be determined according to the open-loop transfer function of the rotating speed loopc *The expression of (a) is:
wherein the content of the first and second substances,
is an open-loop transfer function expression of the rotating speed ring.
3) In the case of a closed speed loop, the closed speed loop transfer function G of the PMSMn(s)oThe expression of (a) is:
H＝1；
further, a rotation speed closed loop transfer function G of the PMSMn(s)oCan be converted into:
the cut-off frequency omega of the closed-loop transfer function of the speed loopb *The expression of (a) is:
wherein the content of the first and second substances,
is an open-loop transfer function expression of the rotating speed ring.
In summary, theoretically, the cut-off frequency of the PMSM in the closed loop should be smaller than that in the open loop no matter whether the PMSM is in the normal state or the inter-turn blocked fault state.
According to the motor turn-to-turn short circuit fault detection method provided by the invention, a detection scene is set to be that a control system is under the control of a double closed loop (a current loop and a rotating speed loop), and the PMSM is a system with high coupling, and can be firstly decoupled, and the decoupled system structures are respectively shown in fig. 3 and fig. 4.
Further, a PMSM mathematical model with turn-to-turn short circuit faults is established, and an I adopted mathematical model is established in a Matlab/Simulink simulation platform according to the established mathematical modeldThe vector control simulation diagram is 0, and comprises a Park conversion module, an SVPWM module and a PMSM module with turn-to-turn short circuit fault information, wherein the fault information of the PMSM module is given by an external parameter u, and when u is 0, the PMSM is in a normal state; when the value of u is between 0 and 1, indicating that the PMSM has turn-to-turn short circuit fault; and the larger the value of u is, the larger the degree of turn-to-turn short circuit fault of the PMSM is represented.
And then, simulating a current simulation graph and a rotating speed simulation graph of the normal operation and fault operation of the PMSM under open-loop and closed-loop control according to the established simulation graph.
In a simulation experiment, when a fault motor is under open-loop control and closed-loop control respectively, a VKF-OT algorithm is utilized to extract and compare the third harmonic of the fault phase current of the fault motor, and the fault characteristics of the motor are observed while the closed-loop control is proved to play a role in inhibiting the fault characteristics of the motor.
Furthermore, the fault position is positioned according to the fact that the amplitude of the third harmonic of the short-circuit phase current is far larger than that of the other two phases when the turn-to-turn short-circuit fault occurs, and the severity of the turn-to-turn short-circuit fault is judged according to the slope of a curve that the amplitude of the third harmonic of the current changes along with the speed.
Finally, considering the fault of the motor and the multivariate characteristics of the fault phenomenon, in order to judge whether the fault phenomenon of the motor is caused by turn-to-turn short circuit, third harmonic and fifth harmonic of fault current are analyzed by combining a wavelet analysis method, a neural network analysis method and the like, so that the occurrence of PMSM turn-to-turn short circuit fault is determined.
In summary, the inter-turn short circuit fault online detection method, the inter-turn short circuit fault online detection device, the motor and the operation machine provided by the invention can be used for judging the running state of the motor to be detected according to the fault detection value by extracting the characteristic harmonic of the three-phase constant-value current of the motor under closed-loop control and converting the related frequency band energy of the characteristic harmonic, so that the inter-turn short circuit fault of the permanent magnet motor under double closed-loop control can be monitored online, whether the fault phenomenon of the permanent magnet motor is caused by the early-occurring inter-turn short circuit can be effectively distinguished, and the detection precision is high.
Fig. 7 is a schematic structural diagram of an electronic device provided in the present invention, and as shown in fig. 7, the electronic device may include: a processor (processor)710, a communication Interface (Communications Interface)720, a memory (memory)730, and a communication bus 740, wherein the processor 710, the communication Interface 720, and the memory 730 communicate with each other via the communication bus 740. Processor 710 may invoke logic instructions in memory 730 to perform a motor turn-to-turn short fault detection method comprising: acquiring a three-phase stator current signal of a motor to be tested at the current rotating speed based on double closed-loop control; extracting characteristic harmonic waves related to turn-to-turn short circuit in the three-phase stator current signals to serve as fault detection signals; and determining the running state of the motor to be detected according to the characteristic frequency information of the fault detection signal.
In addition, the logic instructions in the memory 730 can be implemented in the form of software functional units and stored in a computer readable storage medium when the software functional units are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
In another aspect, the present invention also provides a computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, which when executed by a computer, enable the computer to perform the motor turn-to-turn short circuit fault detection method provided by the above methods, the method comprising: acquiring a three-phase stator current signal of a motor to be tested at the current rotating speed based on double closed-loop control; extracting characteristic harmonic waves related to turn-to-turn short circuit in the three-phase stator current signals to serve as fault detection signals; and determining the running state of the motor to be detected according to the characteristic frequency information of the fault detection signal.
In yet another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program being implemented by a processor to execute the motor turn-to-turn short fault detection method provided in the above embodiments, the method including: acquiring a three-phase stator current signal of a motor to be tested at the current rotating speed based on double closed-loop control; extracting characteristic harmonic waves related to turn-to-turn short circuit in the three-phase stator current signals to serve as fault detection signals; and determining the running state of the motor to be detected according to the characteristic frequency information of the fault detection signal.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A motor turn-to-turn short circuit fault detection method is characterized by comprising the following steps:
acquiring a three-phase stator current signal of a motor to be tested at the current rotating speed based on double closed-loop control;
extracting characteristic harmonic waves related to turn-to-turn short circuit in the three-phase stator current signals to serve as fault detection signals;
and determining the running state of the motor to be detected according to the characteristic frequency information of the fault detection signal.
2. The method of detecting turn-to-turn short circuit fault of motor according to claim 1, wherein said extracting characteristic harmonics related to turn-to-turn short circuit in said three-phase stator current signals comprises:
extracting characteristic harmonic components related to turn-to-turn short circuit from the three-phase stator current signals by using a Kalman filter in a Matlab VibraTools toolbox;
and acquiring an amplitude envelope curve of the characteristic harmonic component to use the amplitude envelope curve as the characteristic harmonic.
3. The method of detecting an inter-turn short circuit fault of an electric machine according to claim 2, wherein the harmonic signal related to the inter-turn short circuit is a third harmonic signal and/or a fifth harmonic signal.
4. The method for detecting turn-to-turn short circuit fault of motor according to claim 1, wherein the determining the operation state of the motor to be detected according to the characteristic frequency information of the fault detection signal comprises:
obtaining a stator current wavelet decomposition band coefficient energy list of the motor to be detected under the conditions that the current rotating speed of the motor to be detected and the stator winding of the motor to be detected have turn-to-turn short circuit faults of different degrees;
determining a target frequency band where the fundamental frequency of the characteristic harmonic is located in a characteristic frequency reference table;
and selecting the energy of the target frequency band as the characteristic frequency information of the fault detection signal, and determining the running state of the motor to be detected according to the energy of the target frequency band.
5. The method for detecting turn-to-turn short circuit fault of motor according to claim 4, wherein the determining the operation state of the motor to be detected according to the characteristic frequency information of the fault detection signal comprises:
calculating the root mean square value of the energy of the target frequency band according to the characteristic frequency information of the fault detection signal, and taking the root mean square value as a detection root mean square value;
acquiring a root mean square value of sub-band coefficient energy of each characteristic frequency of a target motor in a normal state as a standard root mean square value;
determining a fault detection value according to the detection root mean square value and the standard root mean square value;
and determining the running state of the motor to be detected according to the size of the fault detection value.
6. The method according to claim 5, wherein the function expression for determining the fault detection value according to the detected root mean square value and the standard root mean square value is as follows:
wherein E is a detection root mean square value; e0Is a standard root mean square value; and S is a fault detection value.
7. The method for detecting turn-to-turn short circuit fault of motor according to any one of claims 4-6, wherein before determining the operation state of the motor to be detected according to the characteristic frequency information of the fault detection signal, the method comprises:
simulating three-phase stator current signals of the motor to be tested under various operating conditions;
and decomposing each three-phase stator current signal, calculating the energy root mean square of each sub-band coefficient, and constructing a stator current wavelet decomposition band coefficient energy list set under different working conditions.
8. A motor turn-to-turn short circuit fault detection device is characterized by comprising:
the signal acquisition unit is used for acquiring a three-phase stator current signal of the motor to be detected at the current rotating speed based on double closed-loop control;
the signal extraction unit is used for extracting characteristic harmonic waves related to turn-to-turn short circuit in the three-phase stator current signals and using the characteristic harmonic waves as fault detection signals;
and the state operation unit is used for determining the running state of the motor to be detected according to the characteristic frequency information of the fault detection signal.
9. An electric machine, comprising: the motor comprises a motor body, wherein a current signal acquisition module and a rotating speed acquisition module are arranged on the motor body, the current signal acquisition module is used for acquiring three-phase stator current signals when the motor runs in real time, and the rotating speed acquisition module is used for acquiring the current rotating speed of the motor;
the data sending unit is used for sending the current rotating speed and the three-phase stator current signals to the online detection processor;
the on-line detection processor comprises a memory and a program or an instruction which is stored on the memory and can run on the on-line detection processor, and when the program or the instruction is executed by the on-line detection processor, the steps of the motor turn-to-turn short circuit fault detection method according to any one of claims 1 to 7 are executed.
10. A working machine, characterized in that a motor according to claim 9 is arranged on the working machine.
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