Control method of variable frequency speed regulating three-phase permanent magnet motor

Abstract

The present invention discloses a variable frequency speed regulation three-phase permanent magnet motor control method, which relates to the technical field of permanent magnet motors and solves the problem that in the actual control process, the motor is easily interfered by other external electromagnetic or internal harmonics, thereby causing relevant differences in the accuracy of the corresponding motor during control. The present invention monitors the working speed of the three-phase permanent magnet motor and identifies whether there is a relevant abnormality in the speed based on the associated fundamental frequency. For specific situations where the abnormality exists, it is identified whether the current waveform is interfered with, and from a specific analysis process, it is identified whether the motor is interfered with by electromagnetic interference or harmonic interference. Based on the processing method of step-by-step analysis, it can effectively protect the permanent magnet motor from relevant problems in the operation process, and execute subsequent processing logic to perform associated control to improve the control effect.

Description

Technical Field

[0001] The invention relates to the technical field of permanent magnet motors, in particular to a variable frequency speed regulation three-phase permanent magnet motor control method. Background Art

[0002] Its permanent magnet motor can change the synchronous speed of the rotating magnetic field by changing the power supply frequency, thereby adjusting the motor speed. Since the rotor speed of the three-phase permanent magnet motor is basically synchronized with the speed of the rotating magnetic field (completely synchronized under ideal no-load conditions, and there will be a slight slip under load), changing the frequency can accurately control the motor speed. For example, when the motor needs to run at a lower speed, the power supply frequency is reduced; when the motor needs to run at a high speed, the power supply frequency is increased.

[0003] The application with publication number CN109245643B discloses an anti-interference control method for a marine variable-frequency speed-regulating three-phase asynchronous motor, comprising the following steps: firstly, a mathematical model of the marine variable-frequency speed-regulating three-phase asynchronous motor is established, an integral sliding mode surface is designed according to the mathematical model, and then a speed controller based on an integral sliding mode is designed according to the integral sliding mode surface; then, a generalized proportional integral observer is designed to estimate interference for interference compensation; finally, a composite integral sliding mode speed controller is established, and the output signal of the permanent magnet speed-regulating high-voltage three-phase asynchronous motor is divided into two paths, which are recorded as: a first signal and a second signal; the first signal and the second signal after frequency domain anti-interference processing are respectively subjected to inverse Fourier transformation and overlap processing, and the overlapped signal is the output data after frequency domain anti-interference processing; and then weighted processing is performed to complete the anti-interference processing.

[0004] During the control process of its variable frequency speed regulation three-phase permanent magnet motor, the control process of the corresponding motor is generally completed based on the actual operating fundamental frequency and the associated speed. However, in the actual control process, it is very easy to be interfered by other external electromagnetic or internal harmonics, which leads to relevant differences in the control accuracy of the corresponding motor, resulting in the motor cannot achieve good precision control effect. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a variable frequency speed regulation three-phase permanent magnet motor control method, which solves the problem that in the actual control process, the corresponding motor is easily interfered by other external electromagnetic or internal harmonics, thereby causing relevant differences in the control accuracy of the corresponding motor.

[0006] To achieve the above objectives, the present invention is implemented by the following technical solutions: A variable frequency speed regulation three-phase permanent magnet motor control method comprises the following steps:

[0007] Step 1: Monitor the speed of the permanent magnet motor in real time, and confirm in real time whether the speed of the permanent magnet motor is normal based on the set frequency of the permanent magnet motor at the current moment, and generate a normal signal or an abnormal signal based on the confirmation result. The specific method is as follows:

[0008] S11, based on the fundamental frequency f associated with the stator power supply in the permanent magnet motor at the current moment, confirm the pole pair number p set in the permanent magnet motor, and use Determine the standard speed n associated with the permanent magnet motor at the current moment;

[0009] S12, the standard speed n confirmed in real time i The speed Z monitored in real time i Check, where i represents different current moments, identify the speed Z i Is it satisfied: Z i ∈[n i -Y1,n i +Y1], where Y1 is a preset value. If it is satisfied, no processing is performed. If it is not satisfied, an abnormal signal is generated;

[0010] Step 2: Based on the determined abnormal signal, lock a set of verification cycles, identify the current waveform generated by the corresponding stator during the verification cycle, and identify whether there is interference in the current waveform. If there is interference, generate a signal to be processed. If there is no interference, generate an aging fault signal for direct display. The specific method is as follows:

[0011] S21, based on the determined abnormal signal, record the abnormal moment associated with the abnormal signal, determine a set of verification cycles based on the abnormal moment, wherein the abnormal moment is consistent with the middle moment of the verification cycle, and the verification cycle is a preset cycle, extract the current waveform generated in the verification cycle and synchronously monitor and confirm the current waveform generated after the abnormal moment, generate the current waveform generated in the verification cycle and mark it as the waveform to be analyzed;

[0012] S22, confirm the peak points appearing in the waveform to be analyzed in sequence, mark the waveform segment between adjacent peak points as the peak segment, and then based on the fundamental frequency f set when the permanent magnet motor is running and the associated current wave speed v, use: Bc=v÷f to confirm the standard wavelength Bc of the current waveform;

[0013] Identify the horizontal length C between the corresponding peak points in each group of peak segments k , where k represents different peak segments, and confirms the C associated with several peak segments in the waveform to be analyzed k Are they all satisfied?: C k=Bc, if it is satisfied, it means that there is no interference in the current waveform, and the aging fault signal is directly generated for display. If it is not satisfied, C k =The peak segment of Bc is marked as an abnormal band, and a signal to be processed is generated;

[0014] Step 3: Based on the confirmed signal to be processed, lock the partial segments of the current waveform where interference exists, and based on the specific waveform display state of the subsequent current waveform, identify whether the partial segments appear regularly. If they appear regularly, generate a harmonic interference signal; if they do not appear regularly, generate an electromagnetic interference signal. The specific sub-steps are:

[0015] S31, based on the waveform to be analyzed confirmed in the verification period, the waveform to be analyzed belongs to the current waveform, the abnormal band is locked from the waveform to be analyzed, and then the standard waveform of the current waveform is generated according to the fundamental frequency f, the current wave velocity v and the standard wavelength Bc confirmed by the current waveform, and the waveform segment between adjacent peak points in the standard waveform is locked as the standard band;

[0016] Compare the overlap between the abnormal band and the standard band, and lock the non-overlapping sections between the two groups of bands;

[0017] S32, based on the partial segment confirmed by the waveform to be analyzed and based on the current waveform generated in real time, the partial segment is laterally translated backwards, and it is confirmed whether there is a partial waveform segment completely overlapping with the partial segment in the subsequent waveform segment:

[0018] If it exists, then identify whether this part of the segment appears regularly in the subsequent waveform segment, if so, generate a harmonic interference signal, if not, generate an electromagnetic interference signal;

[0019] If not present, an electromagnetic interference signal is generated;

[0020] Step 4: For the confirmed harmonic interference signal, lock the period of the harmonic interference and the fundamental frequency associated with the current current waveform, perform frequency adjustment at the interference node, monitor the speed of the permanent magnet motor in real time for the confirmed electromagnetic interference signal, and compensate the internal fundamental frequency in real time based on the verification result.

[0021] Preferably, in step S32, the specific method of identifying whether the partial segments appear regularly in the subsequent waveform segments is:

[0022] Record the interval time T1 between this partial waveform segment and the partial song segment, and then use this partial waveform segment as a partial song segment, and use the same method to confirm the partial waveform segment later:

[0023] If there is a partial waveform segment, the corresponding interval time T2 is recorded synchronously, and it is identified whether T1 and T2 meet the condition: T1=T2. If so, it means that this partial segment appears regularly in the subsequent waveform segment. If not, it means that this partial segment does not appear regularly in the subsequent waveform segment.

[0024] If a part of the waveform segment does not exist, it means that this part of the segment does not appear regularly in the subsequent waveform segments.

[0025] Preferably, for the confirmed harmonic interference signal, the specific method of frequency adjustment is:

[0026] Based on the confirmed harmonic interference signal, the interval time associated with the corresponding part of the song segment is confirmed, and the interval time is used as the adjustment period;

[0027] Monitor the partial curves of the current waveform, record the end time associated with the corresponding partial curve, and use this end time as the initial time of frequency adjustment. Perform instantaneous frequency adjustment every set of adjustment cycles. After the adjustment is completed, restore the original fundamental frequency f, and the frequency after instantaneous adjustment is (f-1Hz) or (f+1Hz).

[0028] The specific method of real-time compensation for the confirmed electromagnetic interference signal is as follows:

[0029] The fundamental frequency of normal operation is calibrated as Bf, where Bf is the fundamental frequency set during the original operation. , under the premise of knowing the speed n and the number of pole pairs p of the permanent magnet motor, confirm the actual frequency f associated with the corresponding speed;

[0030] Based on Bf and f associated with the current moment, the compensation frequency is determined: BP=(Bf-f). If BP=0, no compensation is performed at the next moment. If BP>0, the fundamental frequency is increased by |BP| at the next moment. If BP<0, the fundamental frequency is reduced by |BP| at the next moment.

[0031] The present invention provides a variable frequency speed regulating three-phase permanent magnet motor control method. Compared with the prior art, it has the following beneficial effects:

[0032] The present invention monitors the working speed of the three-phase permanent magnet motor, and identifies whether there is a relevant abnormality in the speed based on the associated fundamental frequency. In the specific case where the abnormality exists, it identifies whether the current waveform is disturbed, and from a specific analysis process, it identifies whether the motor is subjected to electromagnetic interference or harmonic interference. Based on the step-by-step analysis processing method, the present invention can effectively protect the relevant problems existing in the operation of the permanent magnet motor, and execute the subsequent processing logic to perform associated control, thereby improving the control effect.

[0033] In response to specific problems identified during actual operation, different control processing logics are used to ensure that the corresponding motor can effectively avoid and solve interference problems during operation, thereby improving the control effect of its permanent magnet motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] First embodiment

[0037] See also Figure 1 The present application provides a variable frequency speed regulation three-phase permanent magnet motor control method, comprising the following steps:

[0038] Step 1: monitor the speed of the permanent magnet motor in real time, and confirm in real time whether the speed of the permanent magnet motor is normal based on the set frequency of the permanent magnet motor at the current moment, and generate a normal signal or an abnormal signal based on the confirmation result, wherein the specific method of confirmation is:

[0039] S11, based on the fundamental frequency f associated with the stator power supply in the permanent magnet motor at the current moment, confirm the pole pair number p set in the permanent magnet motor, and use Determine the standard speed n associated with the permanent magnet motor at the current moment;

[0040] S12, the standard speed n confirmed in real time i The speed Z monitored in real time i Check, where i represents different current moments, identify the speed Z i Is it satisfied: Z i ∈[n i -Y1,n i +Y1], where Y1 is a preset value, and Y1 is generally 30. Its specific value is determined by the operator based on experience. If it is satisfied, no processing is performed. If it is not satisfied, an abnormal signal is generated;

[0041] Specifically, each different operating frequency will cause the corresponding motor to produce a corresponding speed. Based on the corresponding stator operating frequency, this frequency is generally a set value, which is prepared in advance by the relevant operator. The generally set frequency is 50Hz. If the confirmed number of pole pairs is 2, then the confirmed speed is: (60×50)÷2=1500r / min, and the final confirmed speed is 1500r / min;

[0042] Step 2: Based on the determined abnormal signal, a set of verification cycles is locked, and the current waveform generated by the corresponding stator in the verification cycle is identified, and whether there is interference in the current waveform is identified. If there is interference, a signal to be processed is generated. If there is no interference, an aging fault signal is generated for direct display. The specific method for identifying whether there is interference in the current waveform is as follows:

[0043] S21. Based on the determined abnormal signal, record the abnormal moment associated with the abnormal signal, determine a set of verification cycles based on the abnormal moment, wherein the abnormal moment is consistent with the middle moment of the verification cycle, and the verification cycle is a preset cycle, the specific value of which is determined by the operator based on experience, extract the current waveform generated in the verification cycle and synchronously monitor and confirm the current waveform generated after the abnormal moment, generate the current waveform generated in the verification cycle and mark it as the waveform to be analyzed;

[0044] S22, confirm the peak points appearing in the waveform to be analyzed in sequence, mark the waveform segment between adjacent peak points as the peak segment, and then based on the fundamental frequency f set when the permanent magnet motor is running and the associated current wave speed v, use: Bc=v÷f to confirm the standard wavelength Bc of the current waveform;

[0045] Identify the horizontal length C between the corresponding peak points in each group of peak segments k , where k represents different peak segments, and confirms the C associated with several peak segments in the waveform to be analyzed k Are they all satisfied?: C k =Bc, if it is satisfied, it means that there is no interference in this current waveform, and the aging fault signal is directly generated for display (under normal circumstances, the corresponding motor speed changes, but the associated waveform wavelength is in the normal display state, then it is the aging of the internal bearing components that causes the corresponding motor speed to be abnormal, resulting in the corresponding abnormal signal during the monitoring process), if it is not satisfied, it will not meet C k= The peak segment of Bc is marked as an abnormal band, and a signal to be processed is generated (based on this signal to be processed, it means that there is interference in this current waveform, so it is necessary to re-analyze and confirm to identify whether such interference belongs to external electromagnetic interference or harmonic interference generated internally, so as to control the control accuracy and improve the overall control effect of the corresponding motor);

[0046] Step 3: Based on the confirmed signal to be processed, lock the part of the current waveform with interference, and based on the specific waveform display state of the subsequent current waveform, identify whether the part appears regularly. If it appears regularly, generate a harmonic interference signal, if it does not appear regularly, generate an electromagnetic interference signal. Specifically, when electromagnetic interference exists, the corresponding waveform will have a state of frequency decrease or increase, resulting in a related change in the corresponding current waveform. If there is corresponding harmonic interference, periodic fluctuations will occur. For example: the signal frequency of the proposed current waveform is 50Hz, and the generated harmonic frequency can only be 100Hz, 150Hz. When the intensity of the corresponding harmonic is high enough, it will affect the original current waveform. If the harmonic of 150Hz affects the current waveform, then three 50Hz bands will intersect with one 150Hz band, thereby generating corresponding interference. Therefore, in order to avoid such interference, the frequency can be adjusted or changed within the corresponding appropriate period, thereby completing the anti-interference process of the corresponding motor;

[0047] The specific sub-steps for identifying whether some segments appear regularly are as follows:

[0048] S31. Based on the waveform to be analyzed confirmed during the verification period, the waveform to be analyzed belongs to the current waveform. The abnormal band is locked from the waveform to be analyzed. Then, based on the fundamental frequency f, current wave velocity v and standard wavelength Bc confirmed by the current waveform, the expression of the current waveform is confirmed: i=i m sin(wt+initial phase), where I m is the current amplitude, w=2πf represents the angular frequency, t is the time, a standard waveform of this current waveform is generated, and the waveform segment between adjacent peak points in the standard waveform is locked as the standard band;

[0049] Compare the overlap between the abnormal band and the standard band, and lock the non-overlapping sections between the two groups of bands;

[0050] S32, based on the partial segment confirmed by the waveform to be analyzed and based on the current waveform generated in real time, the partial segment is laterally translated backwards, and it is confirmed whether there is a partial waveform segment completely overlapping with the partial segment in the subsequent waveform segment:

[0051] If it exists, then identify whether this part of the segment appears regularly in the subsequent waveform segment, if so, generate a harmonic interference signal, if not, generate an electromagnetic interference signal;

[0052] If not present, an electromagnetic interference signal is generated;

[0053] In step S32, the specific method of identifying whether the partial segments appear regularly in the subsequent waveform segments is:

[0054] Record the interval time T1 between this partial waveform segment and the partial song segment, and then use this partial waveform segment as a partial song segment, and use the same method to confirm the partial waveform segment later:

[0055] If there is a partial waveform segment, the corresponding interval time T2 is recorded synchronously, and it is identified whether T1 and T2 meet the condition: T1=T2. If so, it means that this partial segment appears regularly in the subsequent waveform segment. If not, it means that this partial segment does not appear regularly in the subsequent waveform segment.

[0056] If some waveform segments do not exist, it means that this partial segment does not appear regularly in the subsequent waveform segments;

[0057] Specifically, when there is external electromagnetic interference, the frequency associated with the corresponding current waveform will change, causing the corresponding current waveform to change. There is a very small probability that the same signal interference will occur. Therefore, it is necessary to continue to confirm whether the corresponding parts of the curve appear regularly in the future to ensure the relative accuracy of the confirmation process. On the contrary, if the corresponding waveform segment appears regularly all the time, then it must be affected by the corresponding harmonic interference, resulting in periodic abnormalities.

[0058] Step 4: For the confirmed harmonic interference signal, lock the period of the harmonic interference and the fundamental frequency associated with the current waveform, and adjust the frequency at the interference node to avoid the harmonic interference;

[0059] The specific method of frequency adjustment is as follows:

[0060] Based on the confirmed harmonic interference signal, the interval time associated with the corresponding part of the song segment is confirmed, and the interval time is used as the adjustment period;

[0061] Monitor some of the segments of the current waveform, record the end time associated with the corresponding segments, and use this end time as the initial time of frequency adjustment. Perform instantaneous frequency adjustment every time a group of adjustment cycles are set. After the adjustment is completed, restore the original fundamental frequency f, and the frequency after instantaneous adjustment is (f-1Hz) or (f+1Hz). The frequency to be adjusted is selected by the relevant operators. The confirmed adjustment cycle is planned to be 10 seconds, and the original fundamental frequency is 50Hz. In the process of processing the adjustment, the initial time is determined first, and then based on this initial time, the fundamental frequency of the corresponding time is adjusted to 49Hz every 10 seconds to avoid interference. At the end of the adjustment time, it is restored to the original 50Hz.

[0062] According to the confirmed electromagnetic interference signal, the speed of the permanent magnet motor is monitored in real time, and based on the verification result, the internal fundamental frequency is compensated in real time to ensure the control accuracy;

[0063] The specific method of real-time compensation is as follows:

[0064] The fundamental frequency of normal operation is calibrated as Bf, where Bf is the fundamental frequency set in the original operation, generally 50Hz. , under the premise of knowing the speed n and the number of pole pairs p of the permanent magnet motor, confirm the actual frequency f associated with the corresponding speed;

[0065] Based on Bf and f associated with the current moment, the compensation frequency is determined: BP=(Bf-f). If BP=0, no compensation is performed at the next moment. If BP>0, the fundamental frequency is increased by |BP| at the next moment. If BP<0, the fundamental frequency is reduced by |BP| at the next moment.

[0066] Specifically, based on the real-time monitored rotation speed, the corresponding actual frequency can be locked, and then based on the difference between the actual frequency and the set frequency, specific compensation can be performed to ensure the control accuracy of the entire motor.

[0067] Some of the data in the above formulas are dimensionless and numerically calculated. Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0068] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A variable frequency speed regulating three-phase permanent magnet motor control method, characterized in that: The following steps are involved: Step 1: monitor the speed of the permanent magnet motor in real time, and confirm in real time whether the speed of the permanent magnet motor is normal based on the set frequency of the permanent magnet motor at the current moment, and generate a normal signal or an abnormal signal based on the confirmation result; Step 2: Based on the determined abnormal signal, a set of verification cycles is locked, and the current waveform generated by the corresponding stator in the verification cycle is identified, and whether there is interference in the current waveform. If there is interference, a signal to be processed is generated; if there is no interference, an aging fault signal is generated for direct display; Step 3: Based on the confirmed signal to be processed, the partial segment of the current waveform with interference is locked, and based on the specific waveform display state of the subsequent current waveform, it is identified whether the partial segment appears regularly. If it appears regularly, a harmonic interference signal is generated; if it does not appear regularly, an electromagnetic interference signal is generated; Step 4: for the confirmed harmonic interference signal, lock the period of the harmonic interference and the fundamental frequency associated with the current current waveform, perform frequency adjustment at the interference node, monitor the speed of the permanent magnet motor in real time for the confirmed electromagnetic interference signal, and compensate the internal fundamental frequency in real time based on the verification result; For the confirmed harmonic interference signal, the specific method of frequency adjustment is as follows: Based on the confirmed harmonic interference signal, the interval time associated with the corresponding part of the song segment is confirmed, and the interval time is used as the adjustment period; Monitor the partial segments defined by the current waveform, record the end time associated with the corresponding partial segments, and use this end time as the initial time of frequency adjustment. Perform instantaneous frequency adjustment every set of adjustment cycles. After the adjustment is completed, restore the original fundamental frequency f, and the frequency after instantaneous adjustment is (f-1Hz) or (f+1Hz). The specific method of real-time compensation for the confirmed electromagnetic interference signal is as follows: The fundamental frequency of normal operation is calibrated as Bf, where Bf is the fundamental frequency set during the original operation. , under the premise of knowing the speed n and the number of pole pairs p of the permanent magnet motor, confirm the actual frequency f associated with the corresponding speed; Based on Bf and f associated with the current moment, the compensation frequency is determined: BP=(Bf-f). If BP=0, no compensation is performed at the next moment. If BP>0, the fundamental frequency is increased by |BP| at the next moment. If BP<0, the fundamental frequency is reduced by |BP| at the next moment.

2. The variable frequency speed regulating three-phase permanent magnet motor control method according to claim 1 is characterized in that: In step 1, the specific method of confirming whether the speed of the permanent magnet motor is normal is: S11, based on the fundamental frequency f associated with the stator power supply in the permanent magnet motor at the current moment, confirm the pole pair number p set in the permanent magnet motor, and use Determine the standard speed n associated with the permanent magnet motor at the current moment; S12, the standard speed n confirmed in real time i The speed Z monitored in real time i Check, where i represents different current moments, identify the speed Z i Is it satisfied: Z i ∈[n i -Y1,n i +Y1], where Y1 is a preset value. If it is met, no processing is performed. If it is not met, an abnormal signal is generated.

3. The variable frequency speed regulating three-phase permanent magnet motor control method according to claim 1, characterized in that: In step 2, the specific method of identifying whether there is interference in the current waveform is: S21, based on the determined abnormal signal, record the abnormal moment associated with the abnormal signal, determine a set of verification cycles based on the abnormal moment, wherein the abnormal moment is consistent with the middle moment of the verification cycle, and the verification cycle is a preset cycle, extract the current waveform generated in the verification cycle and synchronously monitor and confirm the current waveform generated after the abnormal moment, generate the current waveform generated in the verification cycle and mark it as the waveform to be analyzed; S22, confirm the peak points appearing in the waveform to be analyzed in sequence, mark the waveform segment between adjacent peak points as the peak segment, and then based on the fundamental frequency f set when the permanent magnet motor is running and the associated current wave speed v, use: Bc=v÷f to confirm the standard wavelength Bc of the current waveform; Identify the horizontal length C between the corresponding peak points in each group of peak segments k , where k represents different peak segments, and confirms the C associated with several peak segments in the waveform to be analyzed k Are they all satisfied?: C k =Bc, if it is satisfied, it means that there is no interference in the current waveform, and the aging fault signal is directly generated for display. If it is not satisfied, C k =Bc peak segment is marked as abnormal band, and the signal to be processed is generated.

4. The variable frequency speed regulating three-phase permanent magnet motor control method according to claim 3 is characterized in that: In step 3, the specific sub-steps of generating a harmonic interference signal or an electromagnetic interference signal are: S31, based on the waveform to be analyzed confirmed in the verification period, the waveform to be analyzed belongs to the current waveform, the abnormal band is locked from the waveform to be analyzed, and then the standard waveform of the current waveform is generated according to the fundamental frequency f, the current wave velocity v and the standard wavelength Bc confirmed by the current waveform, and the waveform segment between adjacent peak points in the standard waveform is locked as the standard band; Compare the overlap between the abnormal band and the standard band, and lock the non-overlapping sections between the two groups of bands; S32, based on the partial segment confirmed by the waveform to be analyzed and based on the current waveform generated in real time, the partial segment is laterally translated backwards, and it is confirmed whether there is a partial waveform segment completely overlapping with the partial segment in the subsequent waveform segment: If it exists, then identify whether this part of the segment appears regularly in the subsequent waveform segment, if so, generate a harmonic interference signal, if not, generate an electromagnetic interference signal; If not present, an electromagnetic interference signal is generated.

5. The variable frequency speed regulating three-phase permanent magnet motor control method according to claim 4 is characterized in that: In step S32, the specific method of identifying whether the partial segments appear regularly in the subsequent waveform segments is: Record the interval time T1 between this partial waveform segment and the partial song segment, and then use this partial waveform segment as a partial song segment, and use the same method to confirm the partial waveform segment later: If there is a partial waveform segment, the corresponding interval time T2 is recorded synchronously, and it is identified whether T1 and T2 meet: T1=T2. If so, it means that this partial segment appears regularly in the subsequent waveform segment; If a part of the waveform segment does not exist, it means that this part of the segment does not appear regularly in the subsequent waveform segments.

6. The variable frequency speed regulating three-phase permanent magnet motor control method according to claim 5, characterized in that: If T1≠T2, it means that this part of the segment does not appear regularly in the subsequent waveform segment.

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