Control method and system for permanent magnet DC brushless slotless motor

Abstract

This application relates to the field of motor control technology and discloses a control method and system for a permanent magnet DC brushless slotless motor. The method includes: performing temperature compensation and signal filtering on voltage data from a Hall sensor to obtain rotor position information and temperature characteristic data; performing dynamic magnetic field strength compensation calculation based on the rotor position and temperature data to obtain magnetic field strength parameters; adjusting the amplitude and phase of the three-phase current according to the magnetic field strength parameters to generate current control quantities; extracting and compensating for harmonic components to obtain torque smoothing control commands; calculating and optimizing various losses to generate efficiency optimization parameters; and performing feature extraction and anomaly judgment on operating parameters to output a protection control strategy. This application achieves accurate detection of motor position signals, smooth torque control, optimized loss control, and real-time monitoring and protection of abnormal states under high-temperature conditions, thereby ensuring stable operation and service life of the motor in high-temperature environments.

Description

Technical Field

[0001] The present application relates to the field of motor control, and in particular to a control method and system for a permanent magnet DC brushless slotless motor. Background Art

[0002] Permanent magnet DC brushless slotless motors are increasingly used in high temperature environments due to their simple structure, high efficiency, and high power density. Existing permanent magnet DC brushless slotless motor control methods mainly include position detection control based on Hall sensors, torque control based on current loops, and loss control based on efficiency optimization. These control methods adjust the motor's operating state by controlling the motor's rotor position, stator current, and loss characteristics. Among them, position detection control mainly relies on the Hall sensor to collect rotor position signals, current control mainly controls torque output by adjusting the amplitude and phase of the stator's three-phase current, and efficiency optimization control improves the motor's operating efficiency by analyzing and reducing various types of losses.

[0003] However, the existing control methods have some shortcomings in high temperature environments. First, the signal output characteristics of the Hall sensor will drift in high temperature environments, affecting the accuracy of position detection; second, the harmonic components of the stator current will cause torque pulsation, affecting the smoothness of the motor operation; third, the increase in temperature will lead to increased copper loss and decreased performance of the permanent magnet, and the existing control methods are difficult to effectively compensate for these changes; finally, under abnormal working conditions, the lack of real-time monitoring and protection measures for the motor's operating status can easily cause damage to the motor. Summary of the invention

[0004] The present application provides a control method and system for a permanent magnet DC brushless slotless motor, which is used to achieve accurate detection of motor position signals, smooth control of torque, optimized control of losses, and real-time monitoring and protection of abnormal conditions under high temperature conditions, thereby ensuring the stable operation and service life of the motor in a high temperature environment.

[0005] In the first aspect, the present application provides a control method for a permanent magnet brushless DC slotless motor, and the control method for the permanent magnet brushless DC slotless motor includes: performing temperature compensation on the voltage data of the Hall sensor, eliminating the interference signal through signal filtering, and obtaining the rotor position information and temperature characteristic data; performing dynamic compensation calculation on the magnetic field strength according to the rotor position information and temperature characteristic data, and obtaining the real-time magnetic field strength parameters; adjusting the amplitude and phase of the stator three-phase current according to the real-time magnetic field strength parameters, and generating the optimal stator current control quantity; based on the optimal stator current control quantity, extracting and compensating the harmonic components, and generating the torque smoothing control instruction; according to the torque smoothing control instruction, calculating and optimizing the copper loss, iron loss and mechanical loss, and generating the efficiency optimization control parameters; according to the efficiency optimization control parameters, performing feature extraction and abnormality judgment on the motor operation parameters, and outputting the operation protection control strategy.

[0006] In the second aspect, the present application provides a control system for a permanent magnet brushless DC slotless motor, and the control system of the permanent magnet brushless DC slotless motor includes: a compensation module, which is used to perform temperature compensation on the voltage data of the Hall sensor, eliminate the interference signal through signal filtering, and obtain the rotor position information and temperature characteristic data; a calculation module, which is used to dynamically compensate the magnetic field strength according to the rotor position information and temperature characteristic data, and obtain the real-time magnetic field strength parameters; an adjustment module, which is used to adjust the amplitude and phase of the stator three-phase current according to the real-time magnetic field strength parameters, and generate an optimal stator current control quantity; a processing module, which is used to extract and compensate the harmonic components based on the optimal stator current control quantity, and generate a torque smoothing control instruction; an optimization module, which is used to calculate and optimize the copper loss, iron loss and mechanical loss according to the torque smoothing control instruction, and generate efficiency optimization control parameters; an extraction module, which is used to extract features and judge abnormalities of the motor operation parameters according to the efficiency optimization control parameters, and output an operation protection control strategy.

[0007] In the technical solution provided by the present application, by performing temperature compensation and signal filtering on the Hall sensor voltage data, the drift and interference of the sensor signal in a high temperature environment are effectively eliminated, the accuracy and reliability of the rotor position detection are improved, and an accurate position information basis is provided for subsequent control. In addition, by real-time analysis of the temperature characteristic data, dynamic tracking of temperature changes is achieved. Based on the obtained rotor position information and temperature characteristic data, the magnetic field strength is dynamically compensated and calculated, which effectively compensates for the attenuation of the permanent magnet performance in a high temperature environment and ensures the stability of the magnetic field strength. By accurately adjusting the amplitude and phase of the stator three-phase current, the optimal stator current control quantity is generated, the optimal control of the current vector is achieved, and the torque output capacity of the motor is improved. The harmonic components are extracted and compensated to generate a torque smoothing control command, which effectively suppresses the torque pulsation and improves the stability of the motor operation. By calculating and optimizing the copper loss, iron loss and mechanical loss, the efficiency optimization control parameters are generated, the running loss of the motor is reduced, and the running efficiency is improved. Finally, by extracting the characteristics of the motor's operating parameters and judging abnormalities, the operating protection control strategy is output, which realizes real-time monitoring and protection of the motor's operating status and prevents damage to the motor due to abnormal conditions such as overheating. The overall solution significantly improves the operating performance and reliability of permanent magnet DC brushless slotless motors in high temperature environments through coordinated control of multiple links. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0009] Figure 1 A schematic diagram of an embodiment of a control method for a permanent magnet DC brushless slotless motor in an embodiment of the present application; Figure 2 It is a schematic diagram of an embodiment of a control system of a permanent magnet brushless DC slotless motor in an embodiment of the present application. DETAILED DESCRIPTION

[0010] The embodiment of the present application provides a control method and system for a permanent magnet DC brushless slotless motor. The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" or "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0011] For ease of understanding, the specific process of the embodiment of the present application is described below. Figure 1 An embodiment of the control method of the permanent magnet DC brushless slotless motor in the embodiment of the present application includes: step S101, temperature compensation is performed on the voltage data of the Hall sensor, and the interference signal is eliminated by signal filtering to obtain the rotor position information and temperature characteristic data; step S102, according to the rotor position information and temperature characteristic data, dynamic compensation calculation is performed on the magnetic field strength to obtain the real-time magnetic field strength parameter; step S103, according to the real-time magnetic field strength parameter, the amplitude and phase of the stator three-phase current are adjusted to generate the optimal stator current control quantity; step S104, based on the optimal stator current control quantity, the harmonic component is extracted and compensated to generate a torque smoothing control instruction; step S105, according to the torque smoothing control instruction, the copper loss, iron loss and mechanical loss are calculated and optimized to generate the efficiency optimization control parameter; step S106, according to the efficiency optimization control parameter, the motor operation parameter is feature extracted and abnormal judgment is performed, and the operation protection control strategy is output.

[0012] It is understandable that the execution subject of the present application may be a control system of a permanent magnet DC brushless slotless motor, or a terminal or a server, which is not specifically limited here. The present application embodiment is described by taking a server as the execution subject as an example.

[0013] Specifically, temperature compensation and signal filtering of the Hall sensor voltage data are performed. The Hall sensor detects the rotor position in real time and generates a corresponding voltage output signal. Since the Hall sensor is installed on the circuit board, the voltage signal contains high-frequency interference and power frequency interference, which needs to be processed by a filtering circuit. In the temperature compensation process, the voltage data of the Hall sensor is calculated by the head-to-tail phase difference method to calculate the mutation amount, and the voltage values ​​of two adjacent sampling points are subtracted to obtain the change trend of the voltage data. During temperature compensation, the voltage mutation value is compared with the set threshold value, and the voltage data is corrected in combination with the correction coefficient at the current working temperature. The filtering process adopts a combination of low-pass filtering and band-pass filtering. The cutoff frequency of the low-pass filter is set to 2kHz to filter out high-frequency interference signals, and the center frequency of the band-pass filter is set to 50Hz to eliminate power frequency interference. The obtained rotor position information and temperature characteristic data are further processed, and the real-time magnetic field strength parameters are obtained by dynamic compensation calculation of the magnetic field strength. In this process, the rotor position information is converted into an angle value, and the magnetic field distribution is divided into sampling points. The magnetic field compensation coefficient is obtained by subtracting the reference magnetic field value from the magnetic field sampling data and multiplying it by the inverse of the temperature characteristic data. According to the number of magnetic poles, periodic calculations are performed and the monopole magnetic field compensation value is obtained by cumulative summation. The monopole magnetic field compensation value is integrated in the radial direction, and the dynamic magnetic field change is obtained by considering the influence of centrifugal force. Finally, the dynamic magnetic field change is superimposed on the original magnetic field intensity, and the standardized magnetic field intensity is obtained by normalization.

[0014] Based on the acquired real-time magnetic field strength parameters, the amplitude and phase of the stator three-phase current are adjusted. In this process, the real-time magnetic field strength parameters are decomposed into three components of phase A, phase B, and phase C, and the amplitude of each phase component is calculated. The three-phase magnetic field component data is numerically subtracted from the current stator current to obtain the current compensation deviation. The three-phase coordinate transformation is performed at a phase interval of 120 degrees, and the three-phase compensation current value is obtained by integration and summation. The three-phase compensation current value is corrected for phase angle, and the phase overlap is calculated to obtain the phase adjustment coefficient. The phase adjustment coefficient is multiplied by the three-phase compensation current value, and the normalized current instruction is obtained after normalization. After obtaining the optimal stator current control quantity, the harmonic component is extracted and compensated. The optimal stator current control quantity is analyzed by Fourier decomposition, and the decomposed data is sorted by frequency to obtain the harmonic frequency sequence. The amplitude is calculated for each frequency component, and the main harmonic components are obtained by amplitude screening. The phase angle difference of the main harmonic components is calculated, and the harmonic phase relationship data is obtained by cumulative summation. The harmonic phase relationship data is reversely compensated and calculated, and the compensated current waveform is obtained by numerical reverse superposition. The compensated current waveform is synthesized with the original current waveform, and the smoothed current instruction is obtained after smoothing.

[0015] According to the torque smoothing control command, the various losses of the motor are calculated and optimized. The copper loss is calculated by multiplying the torque smoothing control command with the stator current and squaring it. The iron loss is calculated by squaring the frequency component of the torque smoothing control command and multiplying it with the magnetic permeability. The mechanical loss is obtained by multiplying the square of the rotor speed with the bearing friction coefficient. The total loss value is obtained by weighted summing these three losses, and the change trend of the total loss is calculated to obtain the loss change rate. Finally, the efficiency optimization control parameters are obtained by numerical fitting with the power input data. In the final stage, the feature extraction and abnormality judgment of the motor operating parameters are performed according to the efficiency optimization control parameters. The efficiency optimization control parameters are associated with the operating time, and the speed correction is performed to obtain the standardized operating data. The fluctuation amplitude of the operating data is discretely sampled and differentially calculated to obtain the operating feature sequence. The feature sequence is segmented and averaged according to the time window to obtain the feature judgment threshold. The feature judgment threshold is compared with the real-time operating data to calculate the abnormal deviation index. The abnormal deviation index is subjected to time accumulation calculation and slope analysis to obtain the abnormal development trend. Finally, the severity of the abnormal trend is graded and quantified to obtain the operation protection control strategy.

[0016] For example, when the motor speed is 9000r / min, the voltage data collected by the Hall sensor is sampled every 0.1ms. The temperature characteristic data shows that under a 200℃ working environment, the temperature correction coefficient of the voltage signal is 0.85. In the dynamic compensation calculation of the magnetic field strength, the magnetic field change caused by the centrifugal force is about 3% of the reference magnetic field value. In the regulation process of the stator three-phase current, the calculation of the phase adjustment coefficient takes into account the phase difference of 120 degrees to ensure the balance of the three-phase current. The extraction and compensation processing of the harmonic components show that the main harmonic frequency is contained in the range of 5 times and 7 times the fundamental frequency. The loss calculation results show that under rated working conditions, copper loss accounts for 45% of the total loss, iron loss accounts for 35%, and mechanical loss accounts for 20%. The operation protection strategy issues a warning signal when the deviation exceeds 30% of the set threshold according to the cumulative value of the abnormal deviation index, reduces the speed when it exceeds 50%, and performs a protection shutdown when it exceeds 80%.

[0017] In the embodiment of the present application, by performing temperature compensation and signal filtering on the Hall sensor voltage data, the drift and interference of the sensor signal in a high temperature environment are effectively eliminated, the accuracy and reliability of the rotor position detection are improved, and an accurate position information basis is provided for subsequent control. In addition, by real-time analysis of the temperature characteristic data, dynamic tracking of temperature changes is realized. Based on the obtained rotor position information and temperature characteristic data, the magnetic field strength is dynamically compensated and calculated, which effectively compensates for the attenuation of the permanent magnet performance in a high temperature environment and ensures the stability of the magnetic field strength. By accurately adjusting the amplitude and phase of the stator three-phase current, the optimal stator current control quantity is generated, the optimal control of the current vector is realized, and the torque output capacity of the motor is improved. The harmonic components are extracted and compensated, and torque smoothing control instructions are generated, which effectively suppresses torque pulsation and improves the stability of the motor operation. By calculating and optimizing copper loss, iron loss and mechanical loss, efficiency optimization control parameters are generated, the operating loss of the motor is reduced, and the operating efficiency is improved. Finally, by extracting the characteristics of the motor operating parameters and judging abnormalities, the operation protection control strategy is output, and the real-time monitoring and protection of the motor operating state are realized, and the motor is prevented from being damaged by abnormal conditions such as overheating. The overall solution significantly improves the operating performance and reliability of permanent magnet DC brushless slotless motors in high temperature environments through coordinated control of multiple links.

[0018] In a specific embodiment, the process of executing step S101 may specifically include the following steps: (1) collecting voltage data of the Hall sensor, calculating the difference between every two adjacent sampling points of the voltage data, and obtaining a voltage mutation value; (2) subtracting a preset threshold from the voltage mutation value, and then multiplying it by a temperature correction coefficient to perform numerical calculation to obtain a temperature compensated voltage value; (3) subjecting the temperature compensated voltage value to a low-pass filter with a cutoff frequency of 2 kHz, and then to a band-pass filter with a center frequency of 50 Hz, to obtain filtered voltage data; (4) sampling the filtered voltage data once every 0.1 ms, and performing a difference calculation based on the voltage values ​​of three adjacent sampling points to obtain instantaneous rotor position data; (5) integrating the instantaneous rotor position data within a range of 360 degrees of electrical angle, and performing data fitting by the least squares method to obtain rotor position information; (6) performing mean calculation on the temperature data at the time corresponding to the rotor position information, and accumulating and summing the change in the temperature data per second to obtain temperature characteristic data.

[0019] Specifically, in the control process of the permanent magnet DC brushless slotless motor, the Hall sensor is used as a key position detection element to monitor the rotor position in real time. This monitoring process starts with the collection of the Hall sensor voltage data, and the voltage value output by the Hall sensor is sampled every 0.1 milliseconds. The sampled voltage data contains the rotor position information, but it is also mixed with various interference signals. In order to accurately extract the position information, the voltage values ​​of two adjacent sampling points are calculated to obtain the voltage change, which reflects the speed of change of the rotor position. In the actual operation process, the performance of the Hall sensor will be affected by temperature. When the temperature rises, the sensitivity of the Hall sensor will decrease, resulting in a deviation in the output voltage value. Therefore, the voltage mutation value is temperature compensated. During the compensation process, the calculated voltage mutation value is subtracted from the pre-set standard threshold to obtain the original deviation value. Then this deviation value is multiplied by the temperature correction coefficient, which increases with the increase of temperature and is about 0.85 at an operating temperature of 200°C, so that the temperature-compensated voltage value is obtained.

[0020] After obtaining the temperature compensated voltage value, signal filtering is required to eliminate the influence of interference signals. The filtering process is divided into two steps: first, a low-pass filter with a cutoff frequency of 2kHz is used to filter out high-frequency interference signals. These high-frequency interferences mainly come from the working process of the switching power supply and power electronic devices in the motor control system. After that, the power frequency interference is eliminated by a bandpass filter with a center frequency of 50Hz. This double filtering method can effectively improve the signal-to-noise ratio of the signal and obtain clearer voltage data. The filtered voltage data is periodically sampled with a sampling interval of 0.1 milliseconds. At each sampling, the voltage values ​​of three adjacent sampling points are selected for difference calculation. This three-point difference calculation method can not only reflect the immediate change of the rotor position, but also reflect the trend of position change, thereby obtaining more accurate instantaneous rotor position data.

[0021] In order to obtain the rotor position information, the instantaneous rotor position data is further processed. First, the instantaneous position data is integrated within the 360-degree electrical angle range. The integral result reflects the position change law of the rotor in a complete electrical cycle. Then the least squares method is used to fit the integral data, which can eliminate the influence of random errors and obtain more accurate rotor position information. Finally, the temperature data at the corresponding moment of the rotor position is processed to obtain temperature characteristic data. The processing process includes two aspects: on the one hand, the mean value of the temperature data is calculated to obtain the average temperature level; on the other hand, the change in the temperature data per second is calculated, and these changes are accumulated and summed, so that the temperature change trend can be reflected.

[0022] For example, take a permanent magnet DC brushless slotless motor with a rated speed of 9000 rpm as an example. The raw voltage data collected by the Hall sensor fluctuates around 5V, and the voltage difference between adjacent sampling points varies between 0.1V and 0.3V. These voltage differences are compared with the preset threshold of 0.2V and multiplied by the temperature correction coefficient of 0.85 to obtain the temperature-compensated voltage value. Through the dual processing of 2kHz low-pass filtering and 50Hz band-pass filtering, the high-frequency noise and power frequency interference in the voltage data are effectively suppressed. Sampling is performed every 0.1ms, and three adjacent sampling points are selected for difference calculation to obtain data reflecting the instantaneous position of the rotor. These data are integrated within the range of 360 degrees of electrical angle, and fitted using the least squares method to finally obtain accurate rotor position information. At the same time, the temperature data at the corresponding moment shows that the temperature gradually increases after the motor starts, and the temperature change per second gradually decreases until it stabilizes at the operating temperature. The temperature characteristic data is obtained by calculating the mean value and accumulating the change amount of these temperature data. Through multi-level processing of Hall sensor signals, the rotor position information is effectively extracted, and the accuracy of the data is improved through temperature compensation and signal filtering. At the same time, through the analysis of temperature characteristics, data support is provided for the temperature protection of the motor. Taking into account the characteristics of permanent magnet DC brushless slotless motors working in high temperature environments, the accuracy and reliability of motor control are guaranteed.

[0023] In a specific embodiment, the process of executing step S102 may specifically include the following steps: (1) converting the rotor position information into an angle value, dividing the magnetic field distribution into sampling points according to the angle value, and obtaining magnetic field sampling data; (2) subtracting the reference magnetic field value from the magnetic field sampling data, and then multiplying it by the inverse of the temperature characteristic data to obtain a magnetic field compensation coefficient; (3) periodically repeating the calculation of the magnetic field compensation coefficient according to the number of magnetic poles, and obtaining a monopolar magnetic field compensation value by cumulative summation; (4) integrating the monopolar magnetic field compensation value along the radial distribution, and then multiplying it by the centrifugal force coefficient to obtain a dynamic magnetic field change; (5) numerically superimposing the dynamic magnetic field change with the original magnetic field intensity, and normalizing the superimposed value to obtain a standardized magnetic field intensity; (6) interpolating the standardized magnetic field intensity according to the sampling interval of each electrical angle, and then multiplying it by the magnetic field reference value to obtain a real-time magnetic field intensity parameter.

[0024] Specifically, the rotor position information is converted into an angle value. It is to map the position data in the physical space to the angular space of 0-360 degrees. The converted angle value is used as the reference point for magnetic field distribution sampling, and the position of the magnetic field sampling point is determined by uniform division. The number of sampling points is usually set to 72 points for each pole pair to ensure that the sampling data can fully reflect the magnetic field distribution characteristics. After obtaining the magnetic field sampling data, reference value correction and temperature compensation are required. The magnetic field sampling data is subtracted from the pre-calibrated reference magnetic field value to obtain the deviation value of the magnetic field strength. This deviation value is then multiplied by the reciprocal of the temperature characteristic data to achieve temperature compensation. The reciprocal of the temperature characteristic data is used as a compensation factor, and its value decreases with increasing temperature. It can effectively compensate for the attenuation of magnet performance in a high temperature environment. The magnetic field compensation coefficient obtained in this way reflects the change in magnetic field strength under actual operating conditions. The processing of the magnetic field compensation coefficient needs to take into account the number of magnetic pole pairs of the motor. According to the number of magnetic pole pairs, the magnetic field compensation coefficient is periodically repeated, and the compensation coefficient corresponding to each magnetic pole is accumulated and summed to obtain the unipolar magnetic field compensation value. Considering the magnetic field distribution characteristics of each magnetic pole in the motor makes the compensation more accurate.

[0025] For the processing of the monopole magnetic field compensation value, the influence of radial distribution and centrifugal force needs to be considered. The integral operation of the monopole magnetic field compensation value along the radial distribution can be expressed as:

[0026] ,in: is the dynamic magnetic field variation; is the starting position of radial integration; is the radial integration termination position; is the single-pole magnetic field compensation value at radial position r; is the radial weight function; is the centrifugal force coefficient, which is proportional to the square of the rotational speed.

[0027] The result of the integration is then multiplied by the centrifugal force coefficient to obtain the dynamic magnetic field change. This change reflects the dynamic change characteristics of the magnetic field distribution during high-speed operation. The dynamic magnetic field change is numerically superimposed with the original magnetic field intensity to obtain the actual magnetic field intensity that takes into account various influencing factors. The superimposed values ​​are normalized to unify the numerical range into the standard range.

[0028] Interpolate the standardized magnetic field strength. Perform linear interpolation calculation on the standardized magnetic field strength data according to the sampling interval of the electrical angle to ensure the continuity of the data. The interpolated data is then multiplied by the magnetic field reference value to obtain the real-time magnetic field strength parameter, which is directly used in the motor control process.

[0029] For example, take a brushless slotless motor that uses N45AH sintered NdFeB magnets as permanent magnets. The rotor position information is first converted into an angle value of 0-360 degrees, and the sampling points are divided according to a point every 5 degrees. The magnetic field strength measured at each sampling point is subtracted from the pre-measured reference value to obtain the magnetic field deviation. When the motor operating temperature rises to 200°C, the temperature characteristic data shows that the magnet performance decreases and the compensation coefficient needs to be increased. The compensation coefficients of the four pairs of poles are calculated and accumulated respectively to obtain the compensation value of each pole. Under the high-speed operation condition of 9000r / min, the centrifugal force causes the magnetic field distribution to change. The dynamic change is calculated by radial integration and correction of the centrifugal force coefficient. This change is superimposed on the original magnetic field and normalized according to the maximum magnetic field strength. Finally, interpolation is performed at every 1 degree of electrical angle and multiplied by the calibrated magnetic field reference value to obtain the magnetic field strength parameter. The whole process fully considers the influence of factors such as temperature and speed on the magnetic field, ensuring the accuracy of the magnetic field strength parameter. Through comprehensive analysis of magnetic field distribution and multi-factor compensation, accurate measurement and control of magnetic field strength are achieved. Especially in high temperature and high speed environments, temperature compensation and centrifugal force correction ensure the stability and reliability of motor control.

[0030] In a specific embodiment, the process of executing step S103 may specifically include the following steps: (1) decomposing the real-time magnetic field strength parameter into three components of phase A, phase B, and phase C, calculating the amplitude of each phase component, and obtaining three-phase magnetic field component data; (2) numerically subtracting the three-phase magnetic field component data from the current stator current, and obtaining the current compensation deviation by calculating the phase current difference; (3) performing three-phase coordinate transformation on the current compensation deviation according to a phase interval of 120 degrees, integrating and summing the transformed values, and obtaining the three-phase compensation current value; (4) performing phase angle correction on the three-phase compensation current value, and obtaining the phase adjustment coefficient by calculating the phase overlap; (5) multiplying the phase adjustment coefficient by the three-phase compensation current value, and numerically normalizing the product to obtain a normalized current command; (6) performing amplitude limiting and phase clamping processing on the normalized current command, and obtaining the optimal stator current control amount by numerical conversion.

[0031] Specifically, the real-time magnetic field strength parameters are decomposed according to the structural characteristics of the three-phase motor. This decomposition process converts the spatial magnetic field distribution into three-phase components, namely phase A, phase B and phase C. The 120-degree phase difference between the three phases is taken into account during decomposition, and the magnetic field components of each phase are obtained by vector projection. When calculating the amplitude of each phase component, the root mean square value calculation method is used to ensure that the calculation results can accurately reflect the strength of the magnetic field of each phase. The obtained three-phase magnetic field component data needs to be compared with the actual current flowing in the current stator. This comparison is performed by numerical subtraction to obtain the current difference of each phase. These differences reflect the deviation between the actual current and the ideal current. These deviation data are processed to obtain the current compensation deviation.

[0032] The processing of current compensation deviation needs to consider the characteristics of the three-phase system, and its coordinate transformation process can be expressed as:

[0033] ,in: is the three-phase compensation current value; is the current compensation deviation of the nth phase; is the integration period; is an imaginary unit; is the phase sequence number (1, 2, 3 correspond to A, B, C phases).

[0034] For the phase correction of the three-phase compensation current value, the phase overlap calculation is adopted:

[0035] ,in: is the phase adjustment coefficient; is the weight factor of the kth sampling point; is the phase overlap of the kth sampling point; is the phase angle of the kth sampling point; N is the total number of sampling points.

[0036] After obtaining the phase adjustment coefficient, multiply it with the three-phase compensation current value to adjust the amplitude. In this process, in order to ensure the balance of the current of each phase, the product result is normalized. The normalization process is to divide the current value of each phase by the maximum current value to ensure that the processed current command is within a reasonable range. The final amplitude limiting and phase clamping processing is to ensure the safety of motor operation. Amplitude limiting limits the current command to the range allowed by the motor and the driver, and phase clamping ensures that the phase angle does not exceed the reasonable range to prevent unnecessary torque fluctuations.

[0037] For example, taking a motor that uses a temperature-resistant 220℃ hot air self-adhesive wire as the stator winding as an example, when the real-time magnetic field strength parameter shows that the magnetic field strength of phase A is the largest, the magnetic field components of phases B and C are obtained by three-phase decomposition, which lag by 120 degrees and 240 degrees respectively. After comparing with the current stator current, it is found that under high-temperature working conditions, the actual current is less than the ideal value due to the increase in copper loss, resulting in compensation deviation. These deviations are transformed according to the three-phase coordinate system and integrated within one electrical cycle to obtain the three-phase current value that needs to be compensated. When the three-phase compensation current is phase corrected, the phase adjustment coefficient is calculated by detecting the overlap degree of the current waveforms of each phase. The adjusted current command is normalized to keep the current amplitude within a reasonable range. Finally, the amplitude limit is used to ensure that the current does not exceed the rated value of the winding 15.87A / mm², and the phase clamp controls the phase deviation within ±5 degrees to obtain the final stator current control amount. Through multi-level data processing and compensation, precise control of the stator current is achieved. Especially under high temperature conditions, the motor's operating efficiency is guaranteed through temperature compensation and phase correction. The whole process takes into account the characteristics of the three-phase system to ensure the accuracy and reliability of current control.

[0038] In a specific embodiment, the process of executing step S104 may specifically include the following steps: (1) performing Fourier decomposition on the optimal stator current control quantity, sorting the decomposed data by frequency, and obtaining a harmonic frequency sequence; (2) calculating the amplitude of each frequency component in the harmonic frequency sequence, and obtaining the main harmonic component by amplitude screening; (3) subtracting the phase angles of the main harmonic components, accumulating and summing the phase differences, and obtaining harmonic phase relationship data; (4) performing reverse compensation calculation on the harmonic phase relationship data, and obtaining a compensated current waveform by numerical reverse superposition; (5) synthesizing the compensated current waveform with the original current waveform, and smoothing the synthesized waveform to obtain a smoothed current instruction; (6) performing current amplitude correction and phase calibration on the smoothed current instruction, and obtaining a torque smoothing control instruction by numerical adjustment.

[0039] Specifically, the optimal stator current control quantity is subjected to Fourier decomposition. Fourier decomposition is a method of decomposing a periodic signal into a superposition of sine waves of different frequencies. Through this decomposition, the various frequency components contained in the current waveform can be obtained. The decomposition process discretely samples a current cycle according to the sampling theorem, and the number of sampling points is not less than twice the highest frequency component. The sampled data is subjected to fast Fourier transform to obtain the amplitude and phase information of each frequency component. These frequency components are sorted according to the frequency to form a harmonic frequency sequence. For the obtained harmonic frequency sequence, the amplitude of each frequency component needs to be calculated. The amplitude calculation adopts a complex form, which includes the calculation of the real part and the imaginary part. By comparing the amplitude, the main harmonic components that have a greater impact on the current waveform distortion are screened out. This screening process sets an amplitude threshold and only retains harmonics whose amplitude exceeds a certain proportion of the fundamental component. The main harmonic components usually include the 5th, 7th, 11th and 13th harmonics, which are the main causes of torque pulsation.

[0040] After obtaining the main harmonic components, the phase angles of each harmonic component are analyzed. The phase angle subtraction operation reflects the phase relationship between different harmonics, which directly affects the superposition effect of harmonics. The phase difference is accumulated and summed to obtain the phase relationship data reflecting the overall harmonic characteristics. These data contain the interaction information between the harmonic components.

[0041] For the reverse compensation calculation of harmonic phase relationship data, the following formula is used:

[0042] ,in: is the compensation current waveform; is the amplitude coefficient of the hth harmonic; h is the harmonic order; is the fundamental angular frequency; is the phase compensation angle of the hth harmonic; is the attenuation coefficient of the hth harmonic; is the weight factor of the hth harmonic; H is the highest harmonic order considered.

[0043] The generation of the compensation current waveform takes into account the amplitude, phase and attenuation characteristics of each harmonic component, and offsets the harmonic components in the original waveform by reverse superposition. The compensation current waveform is synthesized with the original current waveform, and the superposition result of the two is smoothed to eliminate the high-frequency components and obtain a smooth current command. The smoothing process uses a digital low-pass filter algorithm, and the filter cutoff frequency is determined according to the dynamic response characteristics of the motor. The smoothed current command is amplitude corrected and phase calibrated. The amplitude correction ensures that the current command does not exceed the rated capacity of the motor and the drive, and the phase calibration ensures that the current vector maintains the best phase relationship with the rotor magnetic field. The corrected and calibrated current command is the final torque smoothing control command.

[0044] For example, take a permanent magnet DC brushless slotless motor using a line-flap hollow cup winding as an example. When the motor runs at a speed of 9000r / min, the optimal stator current control quantity shows obvious 5th and 7th harmonic components after Fourier decomposition. These harmonics come from the characteristics of the slotless structure of the motor and the magnetic field distribution characteristics of the permanent magnet. By Fourier decomposition of the voltage data, it is identified that the amplitude of the 5th harmonic is about 10% of the fundamental wave, and the 7th harmonic is about 8% of the fundamental wave. These two harmonics are the main causes of torque pulsation. When analyzing the phase relationship of the harmonics, it is found that the phase difference of the 5th harmonic relative to the fundamental wave is 126 degrees, and the phase difference of the 7th harmonic is 174 degrees. This phase relationship causes the harmonics to be superimposed at certain moments, exacerbating the torque pulsation. By calculating the reverse compensation waveform, a compensation component with an amplitude and phase opposite to the original harmonic is generated. After superimposing the compensation waveform with the original waveform, the harmonic content is significantly reduced. The smoothed current command has a good sinusoidal characteristic, and the final torque smoothing control command can effectively suppress torque pulsation. Through the precise analysis and processing of the current waveform, the smooth control of torque is achieved. The whole process fully considers the structural characteristics and operating characteristics of the permanent magnet DC brushless slotless motor, ensuring the reliability of the control effect. Especially under high-speed operation conditions, the smoothness of the motor operation is significantly improved through harmonic compensation.

[0045] In a specific embodiment, the process of executing step S105 may specifically include the following steps: (1) multiplying the torque smoothing control instruction by the stator current value, squaring the product, and obtaining a copper loss calculation value; (2) squaring the frequency component of the torque smoothing control instruction, and multiplying the magnetic permeability value to obtain an iron loss calculation value; (3) squaring the rotor speed value, and numerically multiplying the bearing friction coefficient to obtain a mechanical loss calculation value; (4) numerically superimposing the copper loss calculation value, the iron loss calculation value, and the mechanical loss calculation value, and obtaining a total loss value through weighted summation; (5) calculating the slope of the change trend of the total loss value, and obtaining a loss change rate through difference comparison; (6) numerically fitting the loss change rate with the power input data, and obtaining the efficiency optimization control parameter through proportional operation.

[0046] It should be noted that copper loss is caused by the current in the stator winding, and its calculation multiplies the torque smoothing control command with the actual current value flowing through the stator. Since the stator uses hot air self-adhesive wire with a temperature resistance grade of 220℃ as the winding material, the resistance value will increase with the increase of temperature in a high-temperature working environment. Therefore, a square operation is performed on the basis of the product result to obtain an accurate copper loss calculation value. The calculation of iron loss mainly considers the eddy current loss and hysteresis loss generated by the stator core under the action of the alternating magnetic field. The stator core is made of 20WTG1500 electrical cold-rolled silicon steel sheet, and the magnetic permeability varies with frequency and magnetic induction intensity. The torque smoothing control command is frequency analyzed, and the fundamental wave and each harmonic component are extracted, and these frequency components are squared respectively. Then, considering the magnetic permeability characteristics of the silicon steel sheet at different frequencies, the squared frequency component is multiplied by the magnetic permeability value at the corresponding frequency to obtain the iron loss value of each frequency component, and finally the iron loss of each component is superimposed to obtain the total iron loss calculation value.

[0047] Mechanical loss mainly comes from the friction loss of the bearing. The bearing is made of stainless round steel 2Cr13, and the design parameters include radial force 15N and axial force 2N. Mechanical loss is proportional to the square of the speed, so the actual speed value of the rotor is squared. The friction coefficient of the bearing is related to its operating temperature and lubrication state. The friction coefficient under actual working conditions should be considered in the calculation. Multiplying the square of the speed by the friction coefficient can get the calculated value of mechanical loss. The total loss of the motor is the superposition of copper loss, iron loss and mechanical loss. Considering the different degrees of influence of various losses on motor performance, weighting coefficients need to be introduced in the superposition process. The selection of weighting coefficients is based on the characteristics of various losses. For high-speed conditions, the weight of mechanical loss is larger; for heavy-load conditions, the weight of copper loss is larger; and iron loss needs to be considered in all conditions. The total loss value obtained by weighted summation can more accurately reflect the actual loss condition of the motor.

[0048] Perform dynamic analysis on the total loss value and calculate its changing trend over time. This trend is calculated by dividing the difference between the total loss values ​​at adjacent moments by the time interval to obtain the slope of the loss change. The positive or negative slope reflects whether the loss is increasing or decreasing, and the size of the slope reflects the speed of the loss change. By comparing the slope in sections, the loss change rate under different working conditions can be obtained.

[0049] The loss change rate is correlated with the input power data of the motor. The input power data includes the real-time values ​​of voltage and current, and the instantaneous input power can be calculated from these data. The loss change rate and the input power are numerically fitted to establish a corresponding relationship between the two. This relationship is described by a proportional coefficient, and the adjustment of the proportional coefficient directly affects the operating efficiency of the motor. The efficiency optimization control parameters finally obtained are used to guide the operation control of the motor.

[0050] For example, taking a motor using N45AH sintered NdFeB magnets as permanent magnets as an example, when it runs at the rated operating condition of 9000r / min, the stator current is first calculated based on the torque smoothing control command. The current density of the stator winding is 15.87A / mm², which is multiplied by the resistance value and squared to obtain the copper loss value. At the same time, the control command is spectrally analyzed, and the influence of the 5th and 7th harmonics is considered on the basis of the fundamental frequency of 150Hz. These frequency components are squared and multiplied by the magnetic permeability at the corresponding frequency to calculate the iron loss value. For mechanical loss, the speed value of 9000r / min is squared and multiplied by the bearing friction coefficient at a temperature of 200℃ to obtain the mechanical loss value. The values ​​of these three types of losses are weighted and superimposed, and the weight distribution is based on the actual operating characteristics of the motor. The loss change trend is obtained by calculating the loss difference between adjacent sampling periods. This trend is fitted with the input power calculated by voltage and current, and the efficiency optimization control parameters are finally determined. These parameters directly affect the control strategy of the motor. For example, when the loss change rate is too large, the operating parameters will be appropriately reduced, and when the loss is stable, the optimal operating state will be maintained. Through the accurate calculation and dynamic adjustment of various types of losses, the continuous optimization of the motor operating efficiency is achieved. The implementation process of the method fully considers the structural characteristics and working characteristics of the permanent magnet DC brushless slotless motor, ensuring the practicality and reliability of the control effect.

[0051] In a specific embodiment, the process of executing step S106 may specifically include the following steps: (1) numerically associating the efficiency optimization control parameter with the operating time, performing speed correction on the associated data, and obtaining standardized operating data; (2) discretely sampling the fluctuation amplitude of the standardized operating data, and obtaining an operating feature sequence through numerical difference calculation; (3) performing segmented statistics on the operating feature sequence according to the time window, performing mean calculation on the statistical value, and obtaining a feature judgment threshold; (4) comparing the feature judgment threshold with the real-time operating data, and obtaining an abnormal deviation index through difference calculation; (5) performing time accumulation calculation on the abnormal deviation index, performing slope analysis on the accumulated value, and obtaining an abnormal development trend; (6) performing graded quantification on the severity of the abnormal development trend, and obtaining an operating protection control strategy through numerical mapping.

[0052] Specifically, the efficiency optimization control parameters are processed. This process starts with the association of the efficiency optimization control parameters with the operating time, and the efficiency parameters are corresponding to the operating time by establishing a time series. The associated data needs to be corrected for speed, because the efficiency characteristics of the motor at different speeds are different, and the correction benchmark is the rated speed of 9000r / min. The corrected data is standardized to make the data under different working conditions comparable. When processing the standardized operating data, focus on its fluctuation amplitude. The fluctuation amplitude reflects the stability of the motor's operating state and needs to be obtained through discrete sampling. The sampling time interval is set to 0.1ms, which is the same as the sampling period of the Hall sensor. The sampled data points are calculated by differential calculation to obtain the fluctuation change, which constitutes the operating feature sequence. The operating feature sequence contains the dynamic feature information of the motor's operating state.

[0053] The time window analysis method is used to process the operation feature sequence. The length of the time window is set to 1 second, and the feature sequence is statistically analyzed in each window. Statistical analysis includes calculating statistical quantities such as the mean value and standard deviation, where the mean value is used as the benchmark threshold for feature judgment. This threshold reflects the operating feature level of the motor under normal working conditions. After the feature judgment threshold is determined, it needs to be compared with the real-time collected operation data. The comparison process uses the difference calculation method to subtract the real-time data from the threshold to obtain the deviation value. The positive or negative value of the deviation indicates the direction of deviation of the actual operating state from the normal state, and the size of the deviation value indicates the degree of deviation. These deviations constitute abnormal deviation indicators.

[0054] The abnormal deviation index needs to be calculated cumulatively over time to determine the persistence and development trend of the abnormal state. The cumulative calculation takes into account the duration and severity of the deviation, and accumulates the deviation values ​​at each moment in chronological order. The slope analysis is performed on the cumulative results, and the development trend of the abnormality is obtained by calculating the rate of change of the cumulative values ​​at adjacent moments. The slope value of the development trend reflects the speed at which the abnormal state deteriorates. Finally, the abnormal development trend is graded and quantified according to the severity of the abnormal development trend. The classification basis includes the size, duration and development speed of the deviation, and the abnormal state is divided into multiple levels. Different levels correspond to different protection and control strategies, from early warning to reduced speed operation to emergency shutdown. These strategies establish a corresponding relationship with the abnormal level through numerical mapping.

[0055] For example, taking a permanent magnet DC brushless slotless motor with a line-flap hollow cup winding as an example, when the motor is continuously running in a high temperature environment, the efficiency optimization control parameters are recorded over time and corrected according to the ratio of the current speed to the rated speed of 9000r / min. The corrected data shows a trend over time, which reflects the dynamic change process of the motor efficiency. When the operating data is discretely sampled, a data point is collected every 0.1ms, and the difference between adjacent data points is calculated. These difference data constitute a feature sequence that reflects the operating status of the motor. The feature sequence is segmented into 1-second time windows, and the statistical feature values ​​are calculated in each window. These feature values ​​are used as judgment thresholds for subsequent anomaly detection.

[0056] During the real-time monitoring process, when the motor temperature is detected to exceed 200°C, the deviation between the real-time operation data and the judgment threshold begins to increase. These deviations accumulate over time and show the development trend of the abnormal state. For example, when the temperature continues to rise and the winding resistance increases, the slope of the accumulated deviation value will increase significantly, indicating that the abnormal state is intensifying. According to the severity of the abnormal development, the abnormal state is divided into four levels: early warning, mild abnormality, moderate abnormality and severe abnormality. Each level corresponds to a different protection strategy: when the deviation exceeds the threshold by 30%, an early warning signal is issued; when it exceeds 50%, the operating speed is reduced; when it exceeds 80%, a protective shutdown is performed. This hierarchical protection strategy ensures the safe operation of the motor under abnormal conditions. Through the dynamic analysis and processing of the operation data, timely detection and effective protection of the abnormal state of the motor are achieved. The whole process takes into account the characteristics of the permanent magnet DC brushless slotless motor under high temperature conditions, ensuring the accuracy and reliability of monitoring and protection. Especially when the motor faces multiple abnormal conditions, hierarchical protection is achieved through the analysis of the abnormal development trend, which effectively prevents the occurrence of serious faults.

[0057] The control method of the permanent magnet brushless DC slotless motor in the embodiment of the present application is described above. The control system of the permanent magnet brushless DC slotless motor in the embodiment of the present application is described below. Figure 2In the embodiment of the present application, an embodiment of the control system of the permanent magnet DC brushless slotless motor includes: a compensation module 201, which is used to perform temperature compensation on the voltage data of the Hall sensor, eliminate the interference signal through signal filtering, and obtain the rotor position information and temperature characteristic data; a calculation module 202, which is used to perform dynamic compensation calculation on the magnetic field strength according to the rotor position information and temperature characteristic data, and obtain the real-time magnetic field strength parameter; an adjustment module 203, which is used to adjust the amplitude and phase of the stator three-phase current according to the real-time magnetic field strength parameter to generate the optimal stator current control amount; a processing module 204, which is used to extract and compensate the harmonic component based on the optimal stator current control amount to generate a torque smoothing control instruction; an optimization module 205, which is used to calculate and optimize the copper loss, iron loss and mechanical loss according to the torque smoothing control instruction to generate an efficiency optimization control parameter; an extraction module 206, which is used to extract features and judge abnormalities of the motor operation parameters according to the efficiency optimization control parameters, and output an operation protection control strategy.

[0058] Through the cooperation of the above components, the drift and interference of the sensor signal in the high temperature environment are effectively eliminated by temperature compensation and signal filtering of the Hall sensor voltage data, the accuracy and reliability of the rotor position detection are improved, and the accurate position information basis is provided for the subsequent control. In addition, the dynamic tracking of temperature changes is realized through the real-time analysis of the temperature characteristic data. Based on the obtained rotor position information and temperature characteristic data, the magnetic field strength is dynamically compensated and calculated, which effectively compensates for the attenuation of the permanent magnet performance in the high temperature environment and ensures the stability of the magnetic field strength. By accurately adjusting the amplitude and phase of the stator three-phase current, the optimal stator current control quantity is generated, the optimal control of the current vector is realized, and the torque output capacity of the motor is improved. The harmonic components are extracted and compensated to generate torque smoothing control instructions, which effectively suppresses the torque pulsation and improves the smoothness of the motor operation. By calculating and optimizing the copper loss, iron loss and mechanical loss, the efficiency optimization control parameters are generated, the running loss of the motor is reduced, and the running efficiency is improved. Finally, by extracting the characteristics of the motor's operating parameters and judging abnormalities, the operating protection control strategy is output, which realizes real-time monitoring and protection of the motor's operating status and prevents damage to the motor due to abnormal conditions such as overheating. The overall solution significantly improves the operating performance and reliability of permanent magnet DC brushless slotless motors in high temperature environments through coordinated control of multiple links.

[0059] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A control method for a permanent magnet brushless DC slotless motor, characterized in that: The control method of the permanent magnet DC brushless slotless motor includes: performing temperature compensation on the voltage data of the Hall sensor, eliminating the interference signal by signal filtering, and obtaining the rotor position information and temperature characteristic data; performing dynamic compensation calculation on the magnetic field strength according to the rotor position information and temperature characteristic data, and obtaining the real-time magnetic field strength parameter; adjusting the amplitude and phase of the stator three-phase current according to the real-time magnetic field strength parameter, and generating the optimal stator current control quantity; based on the optimal stator current control quantity, extracting and compensating the harmonic component, and generating the torque smoothing control instruction, including: performing Fourier decomposition on the optimal stator current control quantity, sorting the decomposed data by frequency, and obtaining the harmonic frequency sequence; The amplitude of each frequency component in the harmonic frequency sequence is calculated, and the main harmonic components are obtained by amplitude screening; the phase angles of the main harmonic components are subtracted, and the phase differences are accumulated and summed to obtain harmonic phase relationship data; the harmonic phase relationship data is reversely compensated, and a compensated current waveform is obtained by numerical reverse superposition; the compensated current waveform is synthesized with the original current waveform, and the synthesized waveform is smoothed to obtain a smooth current instruction; the current amplitude is corrected and the phase is calibrated for the smooth current instruction, and the torque smoothing control instruction is obtained by numerical adjustment; according to the torque smoothing control instruction, the copper loss, iron loss and mechanical loss are calculated and optimized to generate an efficient and stable torque control instruction. The control parameters are optimized, including: multiplying the torque smoothing control instruction with the stator current value, squaring the product result to obtain the copper loss calculation value; squaring the frequency component of the torque smoothing control instruction, multiplying the magnetic permeability value to obtain the iron loss calculation value; squaring the rotor speed value, numerically multiplying the bearing friction coefficient to obtain the mechanical loss calculation value; numerically superimposing the copper loss calculation value, the iron loss calculation value and the mechanical loss calculation value, and obtaining the total loss value through weighted summation; calculating the slope of the change trend of the total loss value, and obtaining the loss change rate through difference comparison; numerically fitting the loss change rate with the power input data, and obtaining the efficiency optimization control parameter through proportional operation. ; According to the efficiency optimization control parameters, feature extraction and abnormality judgment are performed on the motor operating parameters, and an operation protection control strategy is output, including: numerically associating the efficiency optimization control parameters with the operating time, performing speed correction on the associated data, and obtaining standardized operating data; discretely sampling the fluctuation amplitude of the standardized operating data, and obtaining an operating feature sequence through numerical difference calculation; segmenting the operating feature sequence according to the time window, performing mean calculation on the statistical value, and obtaining a feature judgment threshold; comparing the feature judgment threshold with the real-time operating data, and obtaining an abnormal deviation index through difference calculation; performing time accumulation calculation on the abnormal deviation index, performing slope analysis on the accumulated value, and obtaining an abnormal development trend;The severity of the abnormal development trend is graded and quantified, and the operation protection control strategy is obtained through numerical mapping. ; 2. The control method of the permanent magnet brushless DC slotless motor according to claim 1, characterized in that: The method of performing temperature compensation on the voltage data of the Hall sensor, eliminating the interference signal by signal filtering, and obtaining the rotor position information and temperature characteristic data includes: collecting the voltage data of the Hall sensor, calculating the difference between every two adjacent sampling points of the voltage data, and obtaining a voltage mutation value; subtracting a preset threshold from the voltage mutation value, and then multiplying it by a temperature correction coefficient for numerical calculation, to obtain a temperature compensated voltage value; processing the temperature compensated voltage value through a low-pass filter with a cutoff frequency of 2kHz, and then processing it through a band-pass filter with a center frequency of 50Hz, to obtain filtered voltage data; sampling the filtered voltage data once every 0.1ms, and performing a difference calculation based on the voltage values ​​of three adjacent sampling points to obtain instantaneous rotor position data; integrating and calculating the instantaneous rotor position data within a range of 360 degrees of electrical angle, and performing data fitting by the least squares method to obtain the rotor position information; performing mean calculation on the temperature data at the time corresponding to the rotor position information, and accumulating and summing the change in the temperature data per second to obtain the temperature characteristic data.

3. The control method of the permanent magnet brushless DC slotless motor according to claim 1, characterized in that: The method of dynamically compensating the magnetic field strength according to the rotor position information and the temperature characteristic data to obtain the real-time magnetic field strength parameter includes: converting the rotor position information into an angle value, dividing the magnetic field distribution into sampling points according to the angle value, and obtaining magnetic field sampling data; subtracting the reference magnetic field value from the magnetic field sampling data, and multiplying the result by the inverse of the temperature characteristic data, to obtain a magnetic field compensation coefficient; periodically and repeatedly calculating the magnetic field compensation coefficient according to the number of magnetic poles, and obtaining a monopolar magnetic field compensation value by cumulative summation; integrating the monopolar magnetic field compensation value along the radial distribution, and multiplying the result by the centrifugal force coefficient, to obtain a dynamic magnetic field change; numerically superimposing the dynamic magnetic field change with the original magnetic field strength, and normalizing the superimposed value, to obtain a standardized magnetic field strength; interpolating the standardized magnetic field strength according to the sampling interval of each electrical angle, and multiplying the result by the magnetic field reference value, to obtain the real-time magnetic field strength parameter.

4. The control method of the permanent magnet DC brushless slotless motor according to claim 1, characterized in that: The method of adjusting the amplitude and phase of the stator three-phase current according to the real-time magnetic field strength parameter to generate the optimal stator current control amount includes: decomposing the real-time magnetic field strength parameter into three components of phase A, phase B, and phase C, calculating the amplitude of each phase component, and obtaining three-phase magnetic field component data; numerically subtracting the three-phase magnetic field component data from the current stator current, and obtaining the current compensation deviation by calculating the phase current difference; performing three-phase coordinate transformation on the current compensation deviation at a phase interval of 120 degrees, integrating and summing the transformed values, and obtaining the three-phase compensation current value; performing phase angle correction on the three-phase compensation current value, and obtaining the phase adjustment coefficient by calculating the phase overlap; multiplying the phase adjustment coefficient with the three-phase compensation current value, and numerically normalizing the product result to obtain the normalized current instruction; performing amplitude limiting and phase clamping on the normalized current instruction, and obtaining the optimal stator current control amount by numerical conversion.

5. A control system for a permanent magnet brushless DC slotless motor, used to implement the control method for a permanent magnet brushless DC slotless motor as claimed in any one of claims 1 to 4, characterized in that: The control system of the permanent magnet DC brushless slotless motor includes: a compensation module, which is used to perform temperature compensation on the voltage data of the Hall sensor, eliminate the interference signal through signal filtering, and obtain the rotor position information and temperature characteristic data; a calculation module, which is used to perform dynamic compensation calculation on the magnetic field strength according to the rotor position information and temperature characteristic data, and obtain the real-time magnetic field strength parameter; an adjustment module, which is used to adjust the amplitude and phase of the stator three-phase current according to the real-time magnetic field strength parameter, and generate the optimal stator current control quantity; a processing module, which is used to extract and compensate the harmonic components based on the optimal stator current control quantity, and generate a torque smoothing control instruction; an optimization module, which is used to calculate and optimize the copper loss, iron loss and mechanical loss according to the torque smoothing control instruction, and generate the efficiency optimization control parameter; an extraction module, which is used to extract the characteristics and make abnormal judgment on the motor operation parameters according to the efficiency optimization control parameter, and output the operation protection control strategy.

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