Method, device and apparatus for detecting operating state of drive motor

Abstract

The application provides a method, device and equipment for detecting the working state of a driving motor. The method comprises: receiving a phase current signal of each phase current detected by a sensor, wherein the three-phase current is generated by the driving motor; processing the phase current signal of each phase current according to a discrete Fourier transform mode to obtain a phase current amplitude of each phase current; and determining the working state of the driving motor according to the phase current amplitude of each phase current in the three-phase current. The method quantifies the balance state of the three-phase current of the driving motor, and improves the accuracy of determining the working state of the driving motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric vehicle drive technology, and in particular to a method, device and equipment for detecting the working state of a drive motor. BACKGROUND

[0002] An electric vehicle is powered by an on-board power source, and an electric drive system controls three-phase current to make the drive motor output a desired driving torque. When the single-phase or three-phase load of the drive motor is unbalanced, it will cause three-phase current imbalance, and then make the drive motor generate a large torque ripple, affecting the normal operation of the drive motor. Generally, during the production process, errors in the production process occur, or during use, coil aging occurs, which will cause the three-phase current of the drive motor to be unbalanced. Therefore, before the drive motor is shipped and during use, it is usually detected whether the three-phase current of the drive motor is balanced to determine whether the drive motor is working normally.

[0003] In an ideal case, the phase current amplitude of each phase current in the three-phase current is equal, and the phase is sequentially deviated by 120°. In the time domain, the sum of the three-phase current at each time is equal to 0. Therefore, in the prior art, whether the sum of the three-phase current is 0 is judged to indirectly judge whether the three-phase current is balanced, and then determine whether the working state of the drive motor is normal.

[0004] However, in the above-mentioned manner, only whether the sum of the three-phase current is 0 is used to determine whether the working state of the drive motor is normal. This method is too absolute, and for the working condition that the sum of the three-phase current is 0 but the three-phase current is actually unbalanced, it cannot truly and accurately determine whether the three-phase current is balanced, and then cannot accurately determine whether the working state of the drive motor is normal. SUMMARY

[0005] The present application provides a method, device and equipment for detecting the working state of a drive motor to solve the problem that the three-phase current cannot be accurately determined to be balanced, and the working state of the drive motor cannot be accurately determined.

[0006] In a first aspect, the present application provides a method for detecting the working state of a drive motor, comprising:

[0007] receiving a phase current signal of each phase current in a three-phase current detected by a sensor; wherein the three-phase current is generated by the drive motor;

[0008] processing the phase current signal of each phase current according to a discrete Fourier transform mode to obtain a phase current amplitude of each phase current;

[0009] determining the working state of the drive motor according to the phase current amplitude of each phase current in the three-phase current.

[0010] Optionally, the phase current signal comprises a phase current sample value, a sampling period, and a phase current period; and the phase current signal of each phase current is processed according to a discrete Fourier transform mode to obtain a phase current amplitude of each phase current, comprising:

[0011] For each phase current, each phase current sample value of the phase current is calculated according to the sampling period and the phase current period according to the discrete Fourier transform mode to obtain a real part Fourier coefficient and an imaginary part Fourier coefficient of the phase current;

[0012] The phase current amplitude of each phase current is determined according to the real part Fourier coefficient and the imaginary part Fourier coefficient of each phase current.

[0013] Optionally, the phase current signal comprises a phase current sample value, a sampling period, and a phase current period; and the phase current signal of each phase current is processed according to a discrete Fourier transform mode to obtain a phase current amplitude of each phase current, comprising:

[0014] The phase current sample value of each phase current is weighted processed according to the phase current sample value, the sampling period, and the phase current period of each phase current to obtain a weighted processed phase current sample value of each phase current;

[0015] The sampling period of each phase current and the phase current period of each phase current are calculated to obtain a cosine value corresponding to each phase current; and the sampling period of each phase current and the phase current period of each phase current are calculated to obtain a sine value corresponding to each phase current;

[0016] The weighted processed current sample value of each phase current and the cosine value corresponding to each phase current are multiplied and integrated based on the discrete Fourier transform mode to obtain a real part Fourier coefficient of each phase current;

[0017] The weighted processed current sample value of each phase current and the sine value corresponding to each phase current are multiplied and integrated based on the discrete Fourier transform mode to obtain an imaginary part Fourier coefficient of each phase current.

[0018] Optionally, the working state of the driving motor is determined according to the phase current amplitude of each phase current in the three-phase current, comprising:

[0019] The maximum phase current amplitude in the phase current amplitude and the minimum phase current amplitude in the phase current amplitude are determined according to the phase current amplitude of each phase current in the three-phase current;

[0020] determining a working state of the driving motor according to the maximum phase current amplitude and the minimum phase current amplitude.

[0021] Optionally, the determining the working state of the driving motor according to the maximum phase current amplitude and the minimum phase current amplitude comprises:

[0022] determining a difference between the maximum phase current amplitude and the minimum phase current amplitude to obtain a first amplitude, determining a sum of the maximum phase current amplitude and the minimum phase current amplitude to obtain a second amplitude, and obtaining a ratio parameter according to a ratio between the first amplitude and the second amplitude;

[0023] if it is determined that a value represented by the ratio parameter is greater than a preset value, determining that the three-phase current is in an unbalanced state, and determining that the working state of the driving motor is a state requiring maintenance;

[0024] if it is determined that the value represented by the ratio parameter is less than or equal to the preset value, determining that the three-phase current is in a balanced state, and determining that the working state of the driving motor is a state not requiring maintenance.

[0025] Optionally, after determining that the working state of the driving motor is the state requiring maintenance, the method further comprises:

[0026] sending a prompt information, wherein the prompt information is used to prompt a user to maintain the driving motor.

[0027] Optionally, the phase current signal comprises a phase current period, and before the processing the phase current signal of each phase current according to the discrete Fourier transform to obtain the phase current amplitude of each phase current, the method further comprises:

[0028] if it is determined that a difference between the phase current period and a preset Fourier transform period is less than or equal to a preset threshold, performing the processing the phase current signal of each phase current according to the discrete Fourier transform to obtain the phase current amplitude of each phase current.

[0029] In a second aspect, the present application provides a device for detecting a working state of a driving motor, comprising:

[0030] a receiving unit configured to receive a phase current signal of each phase current in a three-phase current detected by a sensor, wherein the three-phase current is generated by the driving motor;

[0031] a calculating unit configured to process the phase current signal of each phase current according to a discrete Fourier transform to obtain a phase current amplitude of each phase current;

[0032] The determining unit is configured to determine the working state of the driving motor according to a phase current amplitude of each phase current in the three-phase current.

[0033] Optionally, the calculating unit comprises a first calculating module and a second calculating module.

[0034] The first calculating module is configured to calculate each phase current sampling value of each phase current according to a discrete Fourier transform mode based on the sampling period and the phase current period, so as to obtain a real part Fourier coefficient and an imaginary part Fourier coefficient of each phase current.

[0035] The second calculating module is configured to determine the phase current amplitude of each phase current according to the real part Fourier coefficient and the imaginary part Fourier coefficient of each phase current.

[0036] Optionally, the first calculating module comprises a first calculating sub-module, a second calculating sub-module, a third calculating sub-module, a fourth calculating sub-module and a fifth calculating sub-module.

[0037] The first calculating sub-module is configured to perform weighting processing on the phase current sampling value of each phase current based on the phase current sampling value, the sampling period and the phase current period of each phase current, so as to obtain a weighted phase current sampling value of each phase current.

[0038] The second calculating sub-module is configured to perform cosine calculation on the sampling period of each phase current and the phase current period of each phase current, so as to obtain a cosine value corresponding to each phase current.

[0039] The third calculating sub-module is configured to perform sine calculation on the sampling period of each phase current and the phase current period of each phase current, so as to obtain a sine value corresponding to each phase current.

[0040] The fourth calculating sub-module is configured to perform multiplication processing and integration processing on the weighted current sampling value of each phase current and the cosine value corresponding to each phase current based on the discrete Fourier transform mode, so as to obtain the real part Fourier coefficient of each phase current.

[0041] The fifth calculating sub-module is configured to perform multiplication processing and integration processing on the weighted current sampling value of each phase current and the sine value corresponding to each phase current based on the discrete Fourier transform mode, so as to obtain the imaginary part Fourier coefficient of each phase current.

[0042] Optionally, the determining unit comprises a first determining module and a second determining module.

[0043] The first determining module is configured to determine a maximum phase current amplitude from the phase current amplitudes of each of the three-phase currents and a minimum phase current amplitude from the phase current amplitudes of each of the three-phase currents.

[0044] The second determining module is configured to determine the working state of the driving motor according to the maximum phase current amplitude and the minimum phase current amplitude.

[0045] Optionally, the second determining module further includes a first determining submodule, a second determining submodule and a third determining submodule.

[0046] The first determining submodule is configured to determine a difference between the maximum phase current amplitude and the minimum phase current amplitude to obtain a first amplitude, determine a sum of the maximum phase current amplitude and the minimum phase current amplitude to obtain a second amplitude, and obtain a ratio parameter according to a ratio between the first amplitude and the second amplitude.

[0047] The second determining submodule is configured to determine that the three-phase current is in an unbalanced state and determine that the working state of the driving motor is in a maintenance-required state if it is determined that a value represented by the ratio parameter is greater than a preset value.

[0048] The third determining submodule is configured to determine that the three-phase current is in a balanced state and determine that the working state of the driving motor is in a maintenance-free state if it is determined that the value represented by the ratio parameter is less than or equal to the preset value.

[0049] Optionally, the determining module further includes a reminding module configured to send a prompt information, wherein the prompt information is used to prompt a user to maintain the driving motor.

[0050] Optionally, the apparatus for detecting the working state of the driving motor further includes a judging unit.

[0051] The judging unit is configured to, before the step of processing the phase current signal of each of the three-phase currents according to the discrete Fourier transform mode to obtain the phase current amplitude of each of the three-phase currents, execute the step of processing the phase current signal of each of the three-phase currents according to the discrete Fourier transform mode to obtain the phase current amplitude of each of the three-phase currents if it is determined that a difference between the phase current period and a preset Fourier transform period is less than or equal to a preset threshold value.

[0052] In a third aspect, the present application provides an electronic device, which includes a processor and a memory connected with the processor in communication;

[0053] The memory stores computer execution instructions.

[0054] The processor executes computer-executed instructions stored in the memory to implement the method of any one of the above.

[0055] In a fourth aspect, the present application provides a computer readable storage medium, wherein computer-executed instructions are stored in the computer readable storage medium, and the computer-executed instructions are executed by a processor to implement the method of any one of the above.

[0056] The method for detecting the working state of the driving motor provided by the present application receives the phase current signal of each phase current in the three-phase current detected by the sensor, processes the phase current signal of each phase current according to the discrete Fourier transform mode, obtains the phase current amplitude of each phase current, and determines the working state of the driving motor according to the phase current amplitude of each phase current in the three-phase current. Since the phase current amplitude of each phase current in the three-phase current in the frequency domain is obtained, the unbalanced state of the three-phase current is quantified, the practicability is higher, and the phase current of the driving motor that fails can also be accurately obtained, so that the accuracy of determining the working state of the driving motor is improved. BRIEF DESCRIPTION OF DRAWINGS

[0057] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0058] Figure 1 A flowchart of a method for detecting the working state of a driving motor provided by an embodiment of the present application is shown in the figure.

[0059] Figure 2 A flowchart of another method for detecting the working state of a driving motor provided by an embodiment of the present application is shown in the figure.

[0060] Figure 3 A state distribution diagram of a state machine provided by an embodiment of the present application is shown in the figure.

[0061] Figure 4 An example diagram of a discrete Fourier transform module of a state machine provided by an embodiment of the present application is shown in the figure.

[0062] Figure 5 A schematic diagram of a phase current amplitude calculation module of a state machine provided by an embodiment of the present application is shown in the figure.

[0063] Figure 6 A simulation model diagram of a method for detecting the working state of a driving motor provided by an embodiment of the present application is shown in the figure.

[0064] Figure 7 A simulation result diagram of test case 1 tested according to the simulation model is shown in the figure.

[0065] Figure 8A simulation result graph for a test case 2 tested according to a simulation model;

[0066] Figure 9 A simulation result graph for a test case 3 tested according to a simulation model;

[0067] Figure 10 A simulation result graph for a test case 4 tested according to a simulation model;

[0068] Figure 11 A structure diagram of a device for detecting a working state of a driving motor according to an embodiment of the present application;

[0069] Figure 12 A structure diagram of a device for detecting a working state of a driving motor according to another embodiment of the present application;

[0070] Figure 13 A structure diagram of an electronic device according to an embodiment of the present application.

[0071] The above-described drawings show certain embodiments of the present application, and in the following, more detailed descriptions will be given. These drawings and descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0072] The exemplary embodiments will be described in detail herein with reference to the attached drawings. In the following description, the same numbers are used to indicate the same elements throughout the drawings. The following exemplary embodiments are described in detail with reference to the attached drawings. The embodiments described in the following exemplary embodiments do not represent all the technical ideas falling within the scope of the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application, as detailed in the appended claims.

[0073] The terms "first", "second", "third", "fourth" and the like, if any, in the description and in the claims of the present application and in the above description of the drawings merely denote different categories and do not necessarily indicate a specific order, unless otherwise indicated by the context. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the application described herein are capable of operating in other sequences than the one explicitly given in the figures or described herein. Further, the terms "comprise" and "include" and variations thereof, as used in the description and in the claims of the present application, are intended to cover a non-exclusive inclusion such that a process, method, system, product, or apparatus that comprises a list of steps or units are not necessarily limited to those steps or units but can include other not expressly listed steps or units.

[0074] Electric vehicles are developing rapidly in the world due to their clean and energy-saving advantages. In the process of rotation, the instantaneous output torque of the drive motor of the electric vehicle will change over time, but it will always fluctuate around an average value. This phenomenon is called torque ripple. If the torque ripple is too large, it will cause the drive motor to vibrate greatly, affect the speed stability of the vehicle, increase the energy consumption of the motor, and even affect the safe driving of the vehicle. Therefore, it is necessary to control the torque ripple within a safe range.

[0075] Torque ripple is generally caused by aging of the coil of the drive motor or error in the production process of the drive motor, resulting in unbalanced single-phase or three-phase load in the three-phase current of the drive motor. In the prior art, whether the torque ripple of the drive motor is within a safe range is determined by judging whether the three-phase current of the drive motor is balanced, so as to determine whether the drive motor is normal.

[0076] In one example, the balance state of the three-phase current is indirectly determined by judging whether the sum of the three-phase current in the time domain is 0. If the sum of the three-phase current of the drive motor in the time domain is 0, it is determined that the three-phase current of the drive motor is balanced, and if the sum of the three-phase current of the drive motor in the time domain is not 0, it is determined that the three-phase current of the drive motor is unbalanced.

[0077] However, the above scheme has the following defects.(1) The amplitude of each phase current cannot be directly obtained, and the specific situation of three-phase current imbalance cannot be quantified.(2) It cannot cover the working condition that the sum of the three-phase current is 0 and the three-phase current is unbalanced. For example, when each phase of the drive motor is normally insulated from each other, the impedance of a single phase or multiple phases changes, the sum of the three-phase current is still equal to 0, but the three-phase current imbalance at this time cannot be detected.(3) It cannot be applied to an electric drive system with two phase current sensors. For example, many electric drive systems use two phase current sensors to reduce costs. The control system defaults that the sum of the three-phase current is equal to 0, and the third phase current value is calculated for motor control. The prior art cannot be applied to this scenario. Therefore, it is inevitable that the determination of whether the three-phase current is balanced by judging whether the sum of the three-phase current in the time domain is 0 is not accurate, and the working state of the drive motor determined based on this is also not accurate.

[0078] Therefore, in order to solve the above problems, the present application provides a method for detecting the working state of a driving motor. By combining the mathematical tool of discrete Fourier series, the phase current amplitude of each phase current at the fundamental frequency in the frequency domain is extracted, and the phase current amplitude of each phase current is diagnosed respectively, and then the unbalanced state of the three-phase current is determined, and the working state of the driving motor is determined. The unbalanced state of the three-phase current is quantified, and the working condition of the three-phase current in the time domain and the three-phase unbalanced state with a sum of 0 can also be covered. For the electric drive system of the two-phase current sensor, the phase current amplitude of the two phases can also be extracted for diagnosis, which improves the accuracy of determining the balanced state of the three-phase current, and naturally improves the accuracy of the result of determining the working state of the driving motor.

[0079] The technical solutions of the present application and how the technical solutions solve the above technical problems will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0080] Figure 1 A flowchart of a method for detecting the working state of a driving motor is provided in the embodiments of the present application. The execution subject of the present embodiment can be a device for detecting the working state of a driving motor, which is located on an electronic device, as shown in the figure. The device for detecting the working state of a driving motor provided in the present embodiment comprises: Figure 1 The method for detecting the working state of a driving motor provided in the present embodiment comprises:

[0081] S101, receiving a phase current signal of each phase current in the three-phase current detected by a sensor; wherein the three-phase current is generated by a driving motor.

[0082] Wherein, the three-phase current is a current with a phase difference of one-third of a period or 120° phase angle between three components through three wires, each wire as a loop of the other two. In some embodiments, each phase of the three-phase current can be respectively denoted as U phase, V phase and W phase.

[0083] Exemplarily, in the present application, three-phase currents of the driving motor are detected, so the three-phase currents are generated by the driving motor. The sensor can be a phase current sensor. The phase current sensor is a detection device that can sense the information of the measured current and can transform the detected information into an electrical signal or other required form of information output according to certain rules to meet the requirements of information transmission, processing, storage, display, recording and control. The phase current sensor detects the phase current signal of each phase current in the three-phase current and sends it to the device for detecting the working state of the driving motor, which receives the phase current signal of each phase current in the three-phase current detected by the phase current sensor. If the phase current sensor is only one or two, only the phase current signal of any one or any two phases in the three-phase current is detected; if the phase current sensor is three, the phase current signal of each phase in the three-phase current is detected.

[0084] S102, processing the phase current signal of each phase current according to the discrete Fourier transform method to obtain the phase current amplitude of each phase current.

[0085] Exemplarily, since the three-phase current is a sinusoidal signal, the amplitude information of the phase current cannot be obtained in real time in the time domain, so the unbalance of the three-phase current cannot be quantified. The Fourier series of a continuous-time periodic signal has infinitely many discrete frequency components, and the interval of two consecutive frequency components is determined by the period of the continuous-time periodic signal. Unlike continuous-time periodic signals, the Fourier series of a discrete-time periodic signal is periodic, and its angular frequency range is 2π. For example, for a discrete-time periodic signal with a period of t, only t values of the frequency component of the discrete-time periodic signal are needed. Therefore, by using the mathematical tool of discrete Fourier series, the phase current signal of each phase current can be processed to obtain the phase current amplitude of each phase current in the frequency domain, which can solve the problem that the unbalance of the three-phase current cannot be quantified.

[0086] In this embodiment, the specific form of how to process the phase current signal of each phase current according to the discrete Fourier transform method to obtain the phase current amplitude of each phase current is not limited. Exemplarily, the phase current signal of each phase current can be brought into the pre-set phase current amplitude calculation formula processed by the discrete Fourier transform method to obtain the phase current amplitude directly.

[0087] S103, determining the working state of the driving motor according to the phase current amplitude of each phase current in the three-phase current.

[0088] The working state of the driving motor can include a maintenance-required state and a maintenance-free state.

[0089] If the driving motor is in the state of needing maintenance and continues to be used, the driving motor may show the following conditions: overall or partial heating, vibration, low efficiency, additional loss, or other conditions affecting the normal use of the driving motor, and the use is unsafe. If the driving motor is in the state of not needing maintenance, the driving motor shows that all performances are within the standard range.

[0090] Exemplarily, the balance state of the three-phase current can be determined according to the phase current amplitude of each phase current in the three-phase current, and the working state of the driving motor can be determined according to the balance state of the three-phase current. If it is determined that the three-phase current is unbalanced, it is determined that the working state of the driving motor is the state of needing maintenance, and if it is determined that the three-phase current is balanced, it is determined that the working state of the driving motor is the state of not needing maintenance. Moreover, since the phase current amplitude of each phase current is known, it can be determined which phase current of the driving motor has a fault, and the unbalanced state of the three-phase current is quantified, and it is also determined which phase current of the driving motor needs to be maintained.

[0091] In addition, the embodiment does not limit how to determine the balance state of the three-phase current according to the phase current amplitude of each phase current in the three-phase current. Exemplarily, if the phase current amplitudes of each phase current in the three-phase current are all equal, it is determined that the three-phase current is balanced, otherwise, it is determined that the three-phase current is unbalanced; this is applicable to the working condition of the three-phase current sensor detecting the phase current signal of each phase current. Another exemplary, if the phase current amplitudes of each phase current in the three-phase current are all within a preset range, it is determined that the three-phase current is balanced; otherwise, it is determined that the three-phase current is unbalanced; at this time, it is not only applicable to the working condition of the three-phase current sensor detecting the phase current signal of each phase current, but also applicable to most cases of the phase current sensor being only one or two, when the phase current amplitude of any phase current is not within the preset range, it is determined that the three-phase current is unbalanced. Different judgment bases have different judgment results, and the practicability is higher.

[0092] The method for detecting the working state of the driving motor provided by the embodiment receives the phase current signal of each phase current in the three-phase current detected by the sensor, processes the phase current signal of each phase current according to the discrete Fourier transform mode, obtains the phase current amplitude of each phase current, and determines the working state of the driving motor according to the phase current amplitude of each phase current in the three-phase current. Since the phase current amplitude of each phase current in the frequency domain of the three-phase current is obtained according to the discrete Fourier transform mode, the unbalanced state of the three-phase current is quantified, and it is also applicable to part of the working condition including only one or two phase current sensors, the practicability is higher, at the same time, it can also accurately obtain which phase current of the driving motor has a fault, and the accuracy of determining the working state of the driving motor is improved.

[0093] Figure 2Another method for detecting the working state of the driving motor is provided in the embodiments of the present application. The execution subject of the embodiments can be a device for detecting the working state of the driving motor, which is located on an electronic device. For example, the device for detecting the working state of the driving motor can be a state machine, which is generally composed of a state register and a combination logic circuit, can perform state transition according to a control signal according to a preset state, and is a control center for coordinating the actions of related signals and completing specific operations.

[0094] The embodiments take the state machine as the execution subject, as shown in Figure 2 Another method for detecting the working state of the driving motor is provided in the embodiments, which includes the following steps.

[0095] S201, receiving a phase current signal of each phase current in three-phase current detected by a sensor, wherein the three-phase current is generated by the driving motor.

[0096] For example, the state machine receives the phase current signal of each phase current in the three-phase current detected by the phase current sensor. The implementation of step S201 is similar to that of step S101, which will not be described here.

[0097] The phase current signal includes a phase current sample value, a sampling period and a phase current period.

[0098] S202, for each phase current, calculating each phase current sample value of each phase current according to the sampling period and the phase current period according to the discrete Fourier transform method, to obtain the real part Fourier coefficient and the imaginary part Fourier coefficient of each phase current.

[0099] For example, after the state machine receives the phase current signal of each phase current in the three-phase current, for each phase current, the state machine calculates each phase current sample value of each phase current according to the discrete Fourier transform method, to obtain the real part Fourier coefficient and the imaginary part Fourier coefficient corresponding to each phase current.

[0100] For example, the theoretical formula derivation process of the phase current discrete Fourier transform is as follows:

[0101] The discrete Fourier series of each phase current under the sampling period is as follows:

[0102]

[0103] In formula (1-1), the Euler formula is introduced, and the above formula (1-1) is converted into the following formula (1-2):

[0104]

[0105] The formula (1-2) is expanded, and the formula for calculating the Fourier coefficient of the real part Fourier series is recorded as the following formula (1-3):

[0106]

[0107] The formula for calculating the Fourier coefficient of the imaginary part Fourier series is recorded as the following formula (1-4):

[0108]

[0109] And the phase current amplitude of each phase can be recorded as formula (1-5):

[0110]

[0111] In the above formula transformation, Euler's formula is introduced in the discrete Fourier transform scheme, and the complex exponential function is converted into a trigonometric function with cosine as the real part and sine as the imaginary part, which can calculate the discrete Fourier series of the phase current sampling period of the current phase current period. Among them, |X kΩ | is the phase current amplitude, N is the sampling number in the current period, N is a positive integer greater than or equal to 1, n is a positive integer greater than or equal to 0 and less than or equal to N-1, x0 is the initial value, x n is the nth phase current sampling value, e is the natural constant, j is the imaginary unit, since the application extracts the phase current amplitude at the fundamental frequency of each phase current, so the value of k is a constant 1; 2pi is 2π, 2pi is a constant.a k is the Fourier coefficient of the real part Fourier series, which is referred to as the real part Fourier coefficient below; b k is the Fourier coefficient of the imaginary part Fourier series, which is referred to as the imaginary part Fourier coefficient below; cos() represents the cosine value, and sin() represents the sine value.

[0112] Considering that in the above formula, if the sampling frequency changes, the phase current sampling signal will be disturbed, and the sampling error will be amplified. Therefore, on the basis of the above formula, a sampling period mT is introduced to sample multiple phase current periods to reduce the calculation error. Among them, T is the phase current period, if the current frequency is fixed, the m times of the phase current period is the sum of the sampled phase current periods. That is, the formula of the sampling period mT can be recorded as the following formula (1-6):

[0113] mT=T 0+ T1+…+T mn-1 (1-6)

[0114] The formula (1-6) is brought into the formula (1-3) to convert to the following formula (1-7):

[0115]

[0116] Substitute formula (1-6) into formula (1-4), and convert it into the following formula (1-8):

[0117]

[0118] Then, formula (1-5) becomes the following formula (1-9):

[0119]

[0120] Wherein, m is a positive integer greater than or equal to 1. T0 is an initial value, T1 is the phase current period of the first sampling, T mn-1 is the phase current period of the mn-1th sampling, x0 is an initial value, and x1 is the phase current sampling value of the first sampling.

[0121] From this, the calculation formula of the phase current amplitude is derived.

[0122] In this embodiment, after obtaining the phase current sampling value, the phase current period and the sampling period of each phase current, the state machine can be brought into formula (1-7) to calculate the real part Fourier coefficient of each phase current, and brought into formula (1-8) to calculate the imaginary part Fourier coefficient of each phase current.

[0123] S203, according to the real part Fourier coefficient and the imaginary part Fourier coefficient of each phase current, determine the phase current amplitude of each phase current.

[0124] Exemplarily, after calculating the real part Fourier coefficient and the imaginary part Fourier coefficient of each phase current according to the above formula (1-7) and (1-8), the state machine can calculate the phase current amplitude of each phase current according to formula (1-9).

[0125] Wherein, as shown in formula (1-9), Figure 3 Figure 3 ​A state distribution diagram of a state machine is provided in the embodiments of the present application. The state machine can include at least three states, namely, a default state, a discrete Fourier transform state, and a current amplitude calculation state. The state machine is transformed between the three states according to a transformation condition, wherein the embodiments of the present application do not limit the transformation condition of the state machine. Illustratively, the state machine automatically enters the default state after being powered on. When the phase current signal received by the state machine satisfies a preset condition, the state machine enters the discrete Fourier transform state. For example, the current period satisfies the Fourier transform period range 0.075s. When entering the discrete Fourier transform state, the state machine calculates the Fourier coefficient according to the discrete Fourier transform mode, and determines whether the deviation between the actual current period and the Fourier transform period is less than or equal to a preset value. If yes, the state machine enters the phase current amplitude calculation state; otherwise, the state machine returns to the default state. The preset value is not limited. When entering the current amplitude calculation state, the state machine calculates the phase current amplitude of each phase current, and determines the working state of the driving motor according to the phase current amplitude.

[0126] In addition, the state machine can also be logically divided. In actual implementation, the state machine can be integrated in whole or in part into one physical entity, or can be physically separated. The present application does not limit this.

[0127] In one example, the state machine can include a discrete Fourier transform module and a phase current amplitude calculation module. The discrete Fourier transform module calculates the real part Fourier coefficient of each phase current according to formula (1-7), and calculates the imaginary part Fourier coefficient of each phase current according to formula (1-8). The phase current amplitude calculation module calculates the phase current amplitude of each phase current according to formula (1-9).

[0128] In one example, the discrete Fourier transform module of the state machine includes a sampling signal processing submodule, a sine and cosine function submodule, and an integration submodule. As shown in Figure 4 Figure 4 An example diagram of the discrete Fourier transform module of the state machine is provided in the embodiments of the present application.

[0129] The sampling signal processing submodule performs weighted processing on the phase current sampling value of each phase current according to the phase current sampling value, the sampling period, and the phase current period of each phase current, to obtain the weighted phase current sampling value of each phase current.

[0130] Illustratively, the sampling signal processing submodule brings the phase current sampling value, the sampling period, and the phase current period received by the state machine into a preset formula, and performs weighted processing on the phase current sampling value of each phase current in each phase current period of each phase current, to obtain the weighted phase current sampling value of each phase current in each phase current period of each phase current. The preset formula can be ​For example, for any one of the three-phase currents, if the current phase current cycle is recorded as T n-1 , the sampling cycle is recorded as mT, and the phase current sampling value under the current phase current cycle is recorded as x n-1 , then the weighted phase current sampling value is

[0131] The cosine and sine function sub-module calculates the cosine value corresponding to each phase current by performing cosine calculation on the sampling cycle of each phase current and the phase current cycle of each phase current, and calculates the sine value corresponding to each phase current by performing sine calculation on the sampling cycle of each phase current and the phase current cycle of each phase current.

[0132] For example, the cosine and sine function sub-module brings the sampling cycle of each phase current and the current phase current cycle of each phase current into the cosine formula to calculate the cosine value corresponding to each phase current, wherein the cosine value corresponding to each phase current corresponds to the weighted phase current sampling value of each phase current. And the sampling cycle of each phase current and the current phase current cycle of each phase current are brought into the sine formula to calculate the sine value corresponding to each phase current; the sine value corresponding to each phase current also corresponds to the weighted phase current sampling value of each phase current.

[0133] Then, the integral sub-module multiplies and integrates the weighted current sampling value of each phase current and the cosine value corresponding to each phase current based on the discrete Fourier transform method to obtain the real part Fourier coefficient of each phase current. And the weighted current sampling value of each phase current and the sine value corresponding to each phase current are multiplied and integrated based on the discrete Fourier transform method to obtain the imaginary part Fourier coefficient of each phase current.

[0134] For example, the integral sub-module multiplies and integrates the weighted current sampling value of each phase current obtained by the above-mentioned sampling signal processing sub-module and the cosine value corresponding to each phase current obtained by the cosine and sine function sub-module to obtain the real part Fourier coefficient of each phase current. The integral sub-module multiplies and integrates the weighted current sampling value of each phase current obtained by the above-mentioned sampling signal processing sub-module and the sine value corresponding to each phase current obtained by the cosine and sine function sub-module to obtain the imaginary part Fourier coefficient of each phase current.

[0135] The phase current amplitude calculation module can calculate the phase current amplitude of each phase current according to the real part Fourier coefficient and the imaginary part Fourier coefficient of each phase current and formula (1-9).

[0136] S204, determining a maximum phase current amplitude and a minimum phase current amplitude from the phase current amplitudes of each of the three-phase currents.

[0137] In one example, the phase current amplitude calculation module of the state machine comprises a phase current amplitude calculation submodule and a phase current imbalance diagnosis submodule. The phase current amplitude calculation submodule calculates the phase current amplitude of each of the three-phase currents according to the real and imaginary Fourier coefficients of each of the three-phase currents and formula (1-9). The phase current imbalance diagnosis submodule selects the maximum phase current amplitude and the minimum phase current amplitude from the phase current amplitudes of each of the three-phase currents.

[0138] S205, determining the working state of the driving motor according to the maximum phase current amplitude and the minimum phase current amplitude.

[0139] In one example, the phase current imbalance diagnosis submodule of the state machine determines the working state of the driving motor according to the maximum phase current amplitude and the minimum phase current amplitude. In this embodiment, the specific method of determining the working state of the driving motor according to the maximum phase current amplitude and the minimum phase current amplitude is not limited. For example, if the maximum phase current amplitude exceeds a certain limit value and the minimum phase current amplitude is less than a certain limit value, it is determined that the three-phase current is imbalanced. Alternatively, if the difference between the maximum phase current amplitude and the minimum phase current amplitude is greater than a certain limit value, it is also considered that the three-phase current is imbalanced. Then, the working state of the driving motor is determined to be the maintenance state.

[0140] In one example, determining the working state of the driving motor according to the maximum phase current amplitude and the minimum phase current amplitude comprises:

[0141] First, the difference between the maximum phase current amplitude and the minimum phase current amplitude is determined to obtain a first amplitude. The sum of the maximum phase current amplitude and the minimum phase current amplitude is determined to obtain a second amplitude. Then, a ratio parameter is obtained according to the ratio between the first amplitude and the second amplitude.

[0142] Then, it is determined whether the ratio parameter exceeds a preset value. In this embodiment, the specific value of the preset value is not limited. For example, the preset value can be set to 0.1.

[0143] If it is determined that the value represented by the ratio parameter is greater than the preset value, it is determined that the three-phase current is in an imbalanced state, and the working state of the driving motor is determined to be the maintenance state. If it is determined that the value represented by the ratio parameter is less than or equal to the preset value, it is determined that the three-phase current is in a balanced state, and the working state of the driving motor is determined to be the non-maintenance state.

[0144] In one example, Figure 5A schematic diagram of a phase current amplitude calculation module of a state machine is provided in the embodiments of the present application. As shown in Figure 5 The phase current amplitude calculation module of the state machine includes a phase current amplitude calculation submodule and a phase current imbalance diagnosis submodule. The phase current amplitude calculation submodule calculates the U-phase current amplitude, the V-phase current amplitude and the W-phase current amplitude of the three-phase current according to formula (1-9) respectively; the phase current imbalance diagnosis submodule determines the maximum phase current amplitude and the minimum phase current amplitude among the U-phase current amplitude, the V-phase current amplitude and the W-phase current amplitude, and then calculates the ratio of the difference between the maximum phase current amplitude and the minimum phase current amplitude to the sum of the maximum phase current amplitude and the minimum phase current amplitude. If the ratio is greater than 0.1, it is determined that the three-phase current is in an unbalanced state, and it is further determined that the working state of the driving motor is in a maintenance-required state; if the ratio is less than or equal to 0.1, it is determined that the three-phase current is in a balanced state, and it is determined that the working state of the driving motor is in a maintenance-free state, and then the determination result is output.

[0145] In the output result, the phase current amplitude of each phase current in the three-phase current and the determination result can also be recorded and stored at the same time for subsequent maintenance personnel to check.

[0146] S206, issuing a prompt information, wherein the prompt information is used to prompt the user to maintain the driving motor.

[0147] Exemplarily, after determining that the working state of the driving motor is in the maintenance-required state, the state machine can also issue a prompt information to remind the user to maintain the driving motor to avoid safety accidents.

[0148] In one example, before processing the phase current signal of each phase current according to the discrete Fourier transform method to obtain the phase current amplitude of each phase current, it further includes: judging whether the difference between the phase current period and the preset Fourier transform period is within the preset range.

[0149] If it is determined that the difference between the phase current period and the preset Fourier transform period is less than or equal to the preset threshold, the step of processing the phase current signal of each phase current according to the discrete Fourier transform method to obtain the phase current amplitude of each phase current is performed.

[0150] The Fourier transform period refers to the period of calculating the real part Fourier coefficient and the imaginary part Fourier coefficient within one sampling period. The present application does not make specific limitation, which can be changed according to the sampling period.

[0151] For example, after the state machine receives the phase current signal detected by the phase current sensor, which includes the phase current period, it determines whether the difference between the phase current period and a preset Fourier transform period is within a preset range. If the difference is less than or equal to a preset threshold, the state machine transitions from the default state to the Discrete Fourier Transform state, performing the step of processing the phase current signal of each phase current according to the Discrete Fourier Transform method to obtain the phase current amplitude of each phase current. However, if the difference is greater than the preset threshold, the state machine remains in the default state. When the difference is greater than the preset threshold, it indicates that the phase current signal collected by the phase current sensor is of low value, and the accuracy of the result based on this judgment is not high enough.

[0152] This application does not impose any restrictions on the preset threshold. For example, the preset threshold can be 1%. If the difference between the phase current period and the preset Fourier transform period is less than or equal to 1%, then the step of processing the phase current signal of each phase current according to the discrete Fourier transform method to obtain the phase current amplitude of each phase current is performed to further improve the accuracy of the judgment result.

[0153] The method for detecting the operating status of a drive motor provided in this embodiment receives the phase current signal of each phase of the three-phase current detected by a sensor. Then, for each phase current, based on the sampling period and the phase current period, the method calculates the real and imaginary Fourier coefficients of each phase current using the Discrete Fourier Transform (DFT) method. Based on these coefficients, the phase current amplitude of each phase current is determined. Finally, the operating status of the drive motor is determined based on the maximum and minimum phase current amplitudes of each phase current. By calculating the phase current amplitudes, the imbalance of the three-phase currents is quantified. Determining the balance of the three-phase currents based on the maximum and minimum amplitudes further improves the accuracy of determining the drive motor's operating status. Furthermore, when the drive motor is determined to require maintenance, a prompt message is issued to remind the user to perform maintenance, thus improving the safety of drive motor operation.

[0154] Figure 6 This is a simulation model diagram for detecting the operating state of a drive motor, provided as an embodiment of this application. (Refer to...) Figure 6 As shown, the phase current amplitude extraction result of each phase current is observed by setting the phase current signal of each phase in the three-phase current, the motor speed, and the sampling period. The left side inputs the information to be set, the middle program calculates it, and the right side outputs the result of whether the three-phase current is balanced. For example, as shown... Figure 6In the middle, the left side inputs the U-phase current sampling signal and the V-phase current sampling signal, and calculates the W-phase current sampling signal according to a preset algorithm. For example, the amplitudes of the U-phase and V-phase currents are both set to 2048, and the amplitude of the W-phase current is calculated by subtracting the U-phase current amplitude of 2048 from 2048*3, and then subtracting the V-phase current amplitude of 2048, to ensure that the sum of the three-phase currents is 0. Simultaneously, the motor speed is set, for example, 500 rpm (per unit 4500 rpm), and the sampling period is set, for example, 0.0001s, with the execution period being the same as the sampling period. After calculation by the intermediate running program, the right side outputs the phase current amplitude extraction results, including the U-phase current amplitude, V-phase current amplitude, W-phase current amplitude, and specific information on the three-phase current imbalance fault. Furthermore... Figure 6 It also has two reserved bits, 1 and 2, which can be selected for inputting phase current sampling signals.

[0155] For example, Figure 7 The figure shows the simulation results for test case 1 based on the simulation model. Given a sampling amplitude of 2048 for both U and V phase currents, an offset of 2048, a motor speed of 500 rpm, and a sampling period of 0.0001 s, the angular frequency can be calculated as 33.3333*2*pi based on the motor speed. The W phase current sampling is 2048*3 minus the U and V phase currents to ensure the sum of the three phase currents is 0; the simulation results can then be obtained. Figure 7 In the diagram, curves 701, 702, and 703 have the horizontal axis representing time and the vertical axis representing the sampled phase current value; curve 704 has the horizontal axis representing time and the vertical axis representing the phase current amplitude; and straight line 705 has the horizontal axis representing time and the vertical axis representing the three-phase current imbalance signal, displaying 1 when the three-phase current is unbalanced and 0 when the three-phase current is balanced. Figure 7 As shown, curve 701 represents the phase current signal of phase W, curve 702 represents the phase current signal of phase V, curve 703 represents the phase current signal of phase U, and curve 704 represents the phase current amplitudes of phases U, V, and W. The simulation result shows no three-phase imbalance fault reported, and line 705 displays a result of 0. Under cursor 1, the sampled value of the phase current of phase W is 988.0, the sampled value of the phase current of phase V is 4095.0, and the sampled value of the phase current of phase U is 1059.0. The phase current amplitudes of phases U, V, and W are all 2048.0. Since the phase current amplitudes of the three phases are equal, the simulation result shows no three-phase imbalance fault reported.

[0156] Figure 8 This is a simulation result diagram for test case 2, tested according to the simulation model. If... Figure 7 If the sampling amplitude of the U-phase current in test case 1 is reduced to 1024, the amplitude of the V-phase current will remain at 2048, the amplitude of the U-phase current will be 1024, and the amplitude of the W-phase current will be 1773.6, resulting in a three-phase imbalance fault. Figure 8In the diagram, curves 801, 802, and 803 have the horizontal axis representing time and the vertical axis representing the sampled phase current value; curves 804, 805, and 806 have the horizontal axis representing time and the vertical axis representing the phase current amplitude; and line 807 has the horizontal axis representing time and the vertical axis representing the three-phase current imbalance signal, displaying 1 when the three-phase current is unbalanced and 0 when the three-phase current is balanced. Figure 8 As shown, curve 801 represents the phase current signal of phase W, curve 802 represents the phase current signal of phase V, curve 803 represents the phase current signal of phase U, curve 804 represents the phase current amplitude of phase V, curve 805 represents the phase current amplitude of phase W, and curve 806 represents the phase current amplitude of phase U. The simulation result is a three-phase imbalance fault, and line 807 displays a result of 1. Under cursor 1, the sampled value of the phase current of phase W is 2046.0, the sampled value of the phase current of phase V is 1025.0, and the sampled value of the phase current of phase U is 3071.0. The phase current amplitude of phase W is 1773.6, the phase current amplitude of phase V is 2048.0, and the phase current amplitude of phase U is 1024. The phase current amplitudes of the three phases are not equal, therefore, the simulation result is a three-phase imbalance fault.

[0157] Figure 9 The image shows the simulation results for test case 3, based on the simulation model. Given a sampling amplitude of 2048 for both U and V phase currents, an offset of 2048, a motor speed of 15000 rpm, and a sampling period of 0.0001 s, the angular frequency can be calculated as 33.3333*2*pi*30 based on the motor speed. The W phase current sampling is 2048*3 minus the U and V phase currents to ensure the sum of the three phase currents is zero, thus yielding the simulation results. Test case 3, based on test case 1, adds the motor speed. As the speed increases, the number of signal acquisitions per current cycle decreases, resulting in deviations in the extracted U, V, and W phase current amplitudes. Figure 9 In the diagram, curves 901, 902, and 903 have the horizontal axis representing time and the vertical axis representing the sampled phase current value; curve 904 has the horizontal axis representing time and the vertical axis representing the phase current amplitude; and straight line 905 has the horizontal axis representing time and the vertical axis representing the three-phase current imbalance signal, displaying 1 when the three-phase current is unbalanced and 0 when the three-phase current is balanced. Figure 9As shown in the figure, curve 901 is the phase current signal of the W phase, curve 902 is the phase current signal of the V phase, curve 903 is the phase current signal of the U phase, and curve 904 is the phase current amplitude of the U, V and W phases. The simulation result does not report a three-phase unbalanced fault, and straight line 905 shows the result as 0. In the figure, under cursor 1, the phase current sampling value of the W phase is 4091.0, the phase current sampling value of the V phase is 904.0, the phase current sampling value of the U phase is 1148.0, the phase current amplitude of the U phase is 2046.7, the phase current amplitude of the V phase is 2048.6, and the phase current amplitude of the W phase is 2048.8. Although the phase current amplitudes of the three-phase currents are not equal, the difference is very small, and thus the simulation result does not report a three-phase unbalanced fault.

[0158] Figure 10 The following is a simulation result diagram of test case 4 tested according to the simulation model. Figure 9 Based on test case 3, only the U phase current sampling amplitude is reduced to 1024, and the rest remains unchanged. Figure 10 In the figure, the horizontal coordinate in curves 1001, 1002 and 1003 represents time, and the vertical coordinate represents the phase current sampling value; the horizontal coordinate in curves 1004, 1005 and 1006 represents time, and the vertical coordinate represents the phase current amplitude; and the horizontal coordinate in straight line 1007 represents time, and the vertical coordinate represents the three-phase current unbalanced signal, which is displayed as 1 when the three-phase currents are unbalanced and as 0 when the three-phase currents are balanced. The test result is as shown in the figure. Figure 10 As shown in the figure, curve 1001 is the phase current signal of the W phase, curve 1002 is the phase current signal of the V phase, curve 1003 is the phase current signal of the U phase, curve 1004 is the phase current amplitude of the V phase, curve 1005 is the phase current amplitude of the W phase, curve 1006 is the phase current amplitude of the U phase, the simulation result reports a three-phase unbalanced fault, and straight line 1007 shows the result as 1. Under cursor 1, the phase current sampling value of the W phase is 3820.0, the phase current sampling value of the V phase is 238.0, the phase current sampling value of the U phase is 2084.0, the phase current amplitude of the W phase is 1774.9, the phase current amplitude of the V phase is 2048.6, and the phase current amplitude of the U phase is 1023.2. The phase current amplitudes of the three-phase currents are not equal, and thus the simulation result reports a three-phase unbalanced fault.

[0159] In the above test cases 1-4, after the unbalanced state of the three-phase currents is determined, the working state of the driving motor can be determined.

[0160] The following is a device embodiment of the present application, which can be used to execute the method embodiments of the present application. For details not disclosed in the device embodiments of the present application, please refer to the method embodiments of the present application.

[0161] Figure 11A device structure diagram for detecting the working state of a driving motor is provided in an embodiment of the present application. As shown in Figure 11 The device 11 for detecting the working state of the driving motor in the embodiment comprises a receiving unit 111, a calculating unit 112, and a determining unit 113.

[0162] The receiving unit 111 is configured to receive a phase current signal of each phase current detected by a sensor, wherein the three-phase current is generated by the driving motor.

[0163] The calculating unit 112 is configured to process the phase current signal of each phase current according to a discrete Fourier transform mode to obtain a phase current amplitude of each phase current.

[0164] The determining unit 113 is configured to determine the working state of the driving motor according to the phase current amplitude of each phase current in the three-phase current.

[0165] The device for detecting the working state of the driving motor provided in the embodiment can be used to execute the method for detecting the working state of the driving motor in the above embodiment, and has similar implementation principles and technical effects, which will not be described here.

[0166] Figure 12 Another device structure diagram for detecting the working state of a driving motor is provided in an embodiment of the present application. As shown in Figure 12 The device 12 for detecting the working state of the driving motor in the embodiment comprises a receiving unit 121, a calculating unit 122, and a determining unit 123.

[0167] The receiving unit 121 is configured to receive a phase current signal of each phase current detected by a sensor, wherein the three-phase current is generated by the driving motor.

[0168] The calculating unit 122 is configured to process the phase current signal of each phase current according to a discrete Fourier transform mode to obtain a phase current amplitude of each phase current.

[0169] The determining unit 123 is configured to determine the working state of the driving motor according to the phase current amplitude of each phase current in the three-phase current.

[0170] In one example, the calculating unit 122 comprises a first calculating module 1221 and a second calculating module 1222.

[0171] The first calculating module 1221 is configured to, for each phase current, calculate each phase current sampling value of each phase current according to a discrete Fourier transform mode according to a sampling period and a phase current period to obtain a real part Fourier coefficient and an imaginary part Fourier coefficient of each phase current.

[0172] The second calculation module 1222 is configured to determine the phase current amplitude of each phase current according to the real part Fourier coefficient and the imaginary part Fourier coefficient of each phase current.

[0173] In one example, the first calculation module 1221 includes a first calculation submodule 12211, a second calculation submodule 12212, a third calculation submodule 12213, a fourth calculation submodule 12214, and a fifth calculation submodule 12215.

[0174] The first calculation submodule 12211 is configured to perform weighting processing on the phase current sampling value of each phase current according to the phase current sampling value, the sampling period, and the phase current period of each phase current, to obtain the weighted phase current sampling value of each phase current.

[0175] The second calculation submodule 12212 is configured to perform cosine calculation on the sampling period of each phase current and the phase current period of each phase current, to obtain the cosine value corresponding to each phase current.

[0176] The third calculation submodule 12213 is configured to perform sine calculation on the sampling period of each phase current and the phase current period of each phase current, to obtain the sine value corresponding to each phase current.

[0177] The fourth calculation submodule 12214 is configured to perform multiplication processing and integration processing on the weighted current sampling value of each phase current and the cosine value corresponding to each phase current based on the discrete Fourier transform mode, to obtain the real part Fourier coefficient of each phase current.

[0178] The fifth calculation submodule 12215 is configured to perform multiplication processing and integration processing on the weighted current sampling value of each phase current and the sine value corresponding to each phase current based on the discrete Fourier transform mode, to obtain the imaginary part Fourier coefficient of each phase current.

[0179] In one example, the determination unit 123 includes a first determination module 1231 and a second determination module 1232.

[0180] The first determination module 1231 is configured to determine the maximum phase current amplitude and the minimum phase current amplitude from the phase current amplitudes of each phase current in the three-phase current according to the phase current amplitudes of each phase current.

[0181] The second determination module 1232 is configured to determine the working state of the driving motor according to the maximum phase current amplitude and the minimum phase current amplitude.

[0182] In one example, the second determination module 1232 further includes a first determination submodule 12321, a second determination submodule 12322, and a third determination submodule 12323.

[0183] The first determining sub-module 12321 is configured to determine a difference between the maximum phase current amplitude and the minimum phase current amplitude to obtain a first amplitude, determine a sum of the maximum phase current amplitude and the minimum phase current amplitude to obtain a second amplitude, and obtain a ratio parameter according to a ratio between the first amplitude and the second amplitude.

[0184] The second determining sub-module 12322 is configured to determine that the three-phase current is in an unbalanced state and determine that the working state of the driving motor is in a maintenance-required state if it is determined that a value represented by the ratio parameter is greater than a preset value.

[0185] The third determining sub-module 12323 is configured to determine that the three-phase current is in a balanced state and determine that the working state of the driving motor is in a maintenance-free state if it is determined that the value represented by the ratio parameter is less than or equal to the preset value.

[0186] In one example, the determining module 123 further includes a reminding module 1233 configured to send a prompt information, wherein the prompt information is used to prompt a user to maintain the driving motor.

[0187] In one example, the apparatus 12 for detecting the working state of the driving motor further includes a judging unit 124.

[0188] The judging unit 124 is configured to, before obtaining the phase current amplitude of each phase current according to the discrete Fourier transform manner, execute the step of obtaining the phase current amplitude of each phase current according to the discrete Fourier transform manner if it is determined that a difference between the phase current period and a preset Fourier transform period is less than or equal to a preset threshold value.

[0189] The apparatus for detecting the working state of the driving motor provided in the embodiment can be used to execute the method for detecting the working state of the driving motor of the above-described embodiments, and has similar implementation principles and technical effects, which will not be described herein again.

[0190] It should be noted that the division of each module of the above apparatus is only a logical function division, and all or part of the modules can be integrated into one physical entity, or can be physically separated. The modules can all be implemented in the form of software invoked by a processing element; all can be implemented in the form of hardware; or part of the modules can be implemented in the form of software invoked by a processing element, and part of the modules can be implemented in the form of hardware. In addition, the functions of the above data processing modules can also be stored in the form of program code in the memory of the above apparatus, and invoked and executed by a processing element of the above apparatus. The implementation of other modules is similar. In addition, all or part of the modules can be integrated together, or can be independently implemented. The processing element herein can be an integrated circuit having a signal processing capability. In the implementation process, each step of the above method or each of the above modules can be completed by an integrated logic circuit of hardware in the processing element or an instruction in the form of software.

[0191] Figure 13 A structural schematic diagram of an electronic device is provided in the embodiments of the present application. As shown in the figure, the electronic device 13 comprises a processor 131 and a memory 132 in communication connection with the processor. Figure 13

[0192] The memory 132 stores computer execution instructions; the processor 131 executes the computer execution instructions stored in the memory 132 to realize the method for detecting the working state of the driving motor according to any one of the preceding embodiments.

[0193] In one example, the electronic device can be a state machine.

[0194] In the specific implementation of the above electronic device, it should be understood that the processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), etc. The general-purpose processor can be a microprocessor, or the processor can be any conventional processor, etc. The method disclosed in combination with the embodiments of the present application can be directly embodied as hardware processor execution completion, or combined with hardware and software modules in the processor for execution completion.

[0195] The embodiments of the present application further provide a computer readable storage medium, which stores computer execution instructions, and the computer execution instructions are executed by a processor to realize the method for detecting the working state of the driving motor according to any one of the preceding embodiments.

[0196] ​Those skilled in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by computer instruction related hardware. The foregoing program can be stored in a computer readable storage medium. The program executes to perform the steps of the above-mentioned method embodiments; and the foregoing storage medium includes: ROM, RAM, magnetic disk or optical disk and various storage media that can store program codes.

[0197] The embodiments of the present application also provide a computer program product, comprising a computer program, which is executed by a processor to implement the method for detecting the working state of the driving motor according to any one of the preceding embodiments.

[0198] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0199] It should be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the claims that follow.

Claims

1. A method for detecting the operating state of a drive motor, characterized in that, Applied to state machines, the method includes: After the state machine is powered on, it enters the default state. When the phase current signal of each phase current in the three-phase current detected by the sensor meets the preset conditions, it enters the discrete Fourier transform state. The three-phase current is generated by the drive motor. When entering the Discrete Fourier Transform state, the phase current signal of each phase current is processed according to the Discrete Fourier Transform method to calculate the Fourier coefficients, and it is determined whether the deviation between the actual current period and the Fourier transform period is less than or equal to a preset value. If so, the phase current amplitude of each phase current is calculated; otherwise, it returns to the default state. The operating state of the drive motor is determined based on the phase current amplitude of each phase current in the three-phase current.

2. The method according to claim 1, characterized in that, The phase current signal includes phase current sample values, sampling period, and phase current period. The phase current signal of each phase current is processed according to the discrete Fourier transform method to calculate Fourier coefficients, and it is determined whether the deviation between the actual current period and the Fourier transform period is less than or equal to a preset value. If so, the phase current amplitude of each phase current is calculated, including: For each phase current, based on the sampling period and the phase current period, the sampled values ​​of each phase current are calculated according to the discrete Fourier transform method to obtain the real part Fourier coefficients and the imaginary part Fourier coefficients of each phase current. The phase current amplitude of each phase current is determined based on the real and imaginary Fourier coefficients of each phase current.

3. The method according to claim 2, characterized in that, For each phase current, based on the sampling period and the phase current period, the sampled values ​​of each phase current are calculated using the Discrete Fourier Transform method to obtain the real Fourier coefficients and imaginary Fourier coefficients of each phase current, including: Based on the phase current sample value, sampling period and phase current period of each phase current, the phase current sample value of each phase current is weighted to obtain the weighted phase current sample value of each phase current. The sampling period and the phase current period of each phase current are calculated using cosine to obtain the cosine value corresponding to each phase current; and the sampling period and the phase current period of each phase current are calculated using sine to obtain the sine value corresponding to each phase current. Based on the weighted sampled current value of each phase current and the cosine value corresponding to each phase current, the real part Fourier coefficient of each phase current is obtained by multiplying and integrating the sampled value of each phase current using the discrete Fourier transform method. Based on the weighted current sample value of each phase current and the corresponding sine value of each phase current, the discrete Fourier transform method is used to perform multiplication and integration to obtain the imaginary Fourier coefficients of each phase current.

4. The method according to claim 1, characterized in that, The step of determining the operating state of the drive motor based on the phase current amplitude of each phase current in the three-phase current includes: Based on the phase current amplitude of each phase current in the three-phase current, determine the maximum phase current amplitude and the minimum phase current amplitude among the phase current amplitudes. The operating state of the drive motor is determined based on the maximum phase current amplitude and the minimum phase current amplitude.

5. The method according to claim 4, characterized in that, Determining the operating state of the drive motor based on the maximum phase current amplitude and the minimum phase current amplitude includes: The difference between the maximum phase current amplitude and the minimum phase current amplitude is determined to obtain a first amplitude; the sum of the maximum phase current amplitude and the minimum phase current amplitude is determined to obtain a second amplitude; and a ratio parameter is obtained based on the ratio between the first amplitude and the second amplitude. If the value represented by the ratio parameter is determined to be greater than the preset value, then the three-phase current is determined to be unbalanced, and the operating state of the drive motor is determined to be in a state requiring maintenance. If the value represented by the ratio parameter is determined to be less than or equal to the preset value, then the three-phase current is determined to be in a balanced state, and the operating state of the drive motor is determined to be a maintenance-free state.

6. The method according to claim 5, characterized in that, After determining that the operating state of the drive motor is in a state requiring maintenance, the process also includes: A prompt message is issued, which is used to prompt the user to inspect and repair the drive motor.

7. The method according to any one of claims 1-6, characterized in that, The phase current signal includes the phase current period; before processing the phase current signal of each phase current according to the discrete Fourier transform method to obtain the phase current amplitude of each phase current, the method further includes: If the difference between the phase current period and the preset Fourier transform period is determined to be less than or equal to a preset threshold, then the step of processing the phase current signal of each phase current according to the discrete Fourier transform method to obtain the phase current amplitude of each phase current is executed.

8. A device for detecting the operating state of a drive motor, characterized in that, The device includes: The receiving unit is used to enter the default state after power-on. When the phase current signal of each phase current in the three-phase current detected by the receiving sensor meets the preset conditions, it enters the discrete Fourier transform state; wherein, the three-phase current is generated by the drive motor. The calculation unit is used to process the phase current signal of each phase current according to the discrete Fourier transform method to calculate the Fourier coefficient when entering the discrete Fourier transform state, and to determine whether the deviation between the actual current period and the Fourier transform period is less than or equal to a preset value. If so, the phase current amplitude of each phase current is calculated; otherwise, the default state is returned. The determining unit is used to determine the operating state of the drive motor based on the phase current amplitude of each phase current in the three-phase current.

9. An electronic device, characterized in that, The electronic device includes: a processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-7.

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