Method for reducing stator heating of high-speed synchronous permanent magnet motor

Abstract

The invention relates to the technical field of temperature rise adjustment, and particularly discloses a temperature rise adjustment method of a dvdt amplitude reduction filter, which comprises the following steps: S1, setting a voltage range of the filter, and setting an environment temperature range; obtaining the temperature rise of the filter under the same environment temperature and different voltages, and obtaining a curve that the temperature rise of the filter changes along with the voltage and the environment temperature through nonlinear regression analysis; s2, when the temperature rise of the filter is greater than or equal to a preset value, setting an ideal temperature rise value of the filter, obtaining a real-time environment temperature, and substituting the real-time environment temperature into a curve that the temperature rise of the filter changes along with the voltage and the environment temperature to obtain a target voltage; and S3, when the Upeak value of the filter is greater than or equal to a preset value, adjusting the load at a preset fixed load interval until the Upeak value is less than the preset value, and reducing the temperature rise of the filter and the Upeak value. According to the invention, the relationship between the temperature rise of the filter and the Upeak value can be balanced, the service life of equipment is prolonged, and the system performance and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor heat dissipation regulation, and particularly relates to a method for reducing the stator heating of a high-speed synchronous permanent magnet motor. Background Art

[0002] Based on the principle of electromagnetic induction, a high-speed synchronous permanent magnet motor generates the magnetic field of the motor using permanent magnets, without the need for an excitation coil or excitation current. By controlling the speed and current of the motor, the rotation of the motor is achieved. Compared with traditional electrically excited motors, by precisely controlling the current input into the stator region, the speed and torque of the motor can be precisely controlled, so as to adapt to different load requirements. It has significant advantages such as simple structure, reliable operation, small volume, light weight, small loss, and high efficiency, and thus has a very wide range of applications, almost covering all fields of aerospace, national defense, industrial and agricultural production, and daily life.

[0003] With the change of the external load of the high-speed synchronous permanent magnet motor, the current flowing into the stator winding of the high-speed synchronous permanent magnet motor is also constantly changing. Due to the skin effect, the stator generates core loss, and the lost energy is converted into heat, resulting in an increase in the internal temperature of the motor. The magnetic steel contained in the inner rotor of the high-speed synchronous permanent magnet motor is very likely to be demagnetized due to stator heating and the inability to dissipate heat in a short time, so that the motor completely fails or cannot meet the expected performance requirements, greatly shortening the service life of the motor.

[0004] Existing technologies usually adopt heat dissipation devices to reduce the stator temperature of the motor and improve the cooling effect on the stator winding. Since the actual output power of the high-speed synchronous permanent magnet motor is constantly changing under the influence of the external load, the heat generated by the stator also changes accordingly. If a fixed low heat dissipation power is adopted, the internal temperature of the motor will be too high, resulting in motor damage. If a fixed high heat dissipation power is adopted, the heat dissipation energy consumption of the motor will be greatly increased. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for reducing the stator heating of a high-speed synchronous permanent magnet motor, and solve the following technical problems: Since the actual output power of the high-speed synchronous permanent magnet motor is constantly changing under the influence of the external load, the heat generated by the stator also changes accordingly. If a fixed low heat dissipation power is adopted, the internal temperature of the motor will be too high, resulting in motor damage. If a fixed high heat dissipation power is adopted, the heat dissipation energy consumption of the motor will be greatly increased.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A method for reducing the stator heating of a high-speed synchronous permanent magnet motor, characterized by comprising the following steps: S1, adjust the magnitude of the external load connected to the high-speed synchronous permanent magnet motor at intervals, and obtain the stator winding temperature of the high-speed synchronous permanent magnet motor in real time; S2, without turning on the heat dissipation device under any external load, generate a curve of the stator winding temperature changing with time and label it as the temperature rise curve Si, where i is a positive integer; S3, under any external load, turn on the heat dissipation device, preset an initial heat dissipation power P0, and obtain the stator winding temperature of the high-speed synchronous permanent magnet motor in real time. If the temperature of the stator winding continues to change when it rises to the temperature limit, increase it gradually at the preset threshold based on the initial heat dissipation power P0, and use the increased heat dissipation power as the new initial heat dissipation power and label it as Pi. If there is any initial heat dissipation power Pi at which the temperature of the stator winding no longer changes when it rises to the temperature limit, record the heat dissipation power of the heat dissipation device at this time and label it as the optimal heat dissipation power for this external load, and generate a curve of the stator winding temperature changing with time at the optimal heat dissipation power and label it as the standard temperature rise curve Di; S4, in the actual environment, when the motor starts, preset an observation time T1, obtain the actual temperature rise curve of the stator winding within the observation period T1, compare and screen the current actual temperature rise curve with the temperature rise curve Si to obtain the optimal temperature rise curve, use the external load corresponding to the optimal temperature rise curve as the external load of the current motor, turn on the motor heat dissipation device and select the optimal heat dissipation power of the current external load as the initial heat dissipation power; S5, obtain the actual temperature rise curve of the motor within the time period T2 after turning on the heat dissipation device in real time, and perform a similarity comparison with the standard temperature rise curve to obtain a similarity value H. If the similarity value is less than the preset threshold, adjust the heat dissipation power of the current heat dissipation device. If the similarity value is greater than the preset threshold, keep the heat dissipation power of the current heat dissipation device.

[0007] As a further solution of the present invention: the process of obtaining the stator winding temperature is as follows: Obtain the stator winding temperature data at different windings of the stator core through temperature sensors, calculate the average value of the temperature data of each stator winding to obtain the average temperature, and generate a curve of the temperature changing with time with time as the abscissa and the average temperature as the ordinate according to the observation time and the average temperature.

[0008] As a further solution of the present invention: the temperature sensors are evenly distributed along the stator core at different windings of the stator core, and several of the temperature sensors are evenly distributed on each stator winding.

[0009] As a further solution of the present invention: the process of generating the standard temperature rise curve Di is as follows: Under any external load, select the optimal power corresponding to the load as the initial heat dissipation power for motor starting and obtain the stator winding temperature of the high-speed synchronous permanent magnet motor in real time. When the stator winding temperature reaches the temperature limit, generate a change curve of temperature with time with time as the abscissa and stator winding temperature as the ordinate and mark it as the standard temperature rise curve.

[0010] As a further solution of the present invention: the process of obtaining the optimal temperature rise curve is as follows: Obtain the stator winding temperature at the moment before motor starting and mark it as t 初 , take the t 初 temperature as the initial temperature, the time period T1 as the extraction duration, intercept the corresponding curve segment from the temperature rise curve Si under any load and mark it as the comparison temperature rise curve, obtain several comparison temperature rise curves, construct a fitting function Y = KX + L to fit all comparison temperature rise curves, and obtain the values of K and L by the least square method, calculate the difference between the K value of any comparison temperature rise curve and the K1 value of the current actual temperature rise curve, select the K value with the smallest difference from K1, and select the comparison temperature rise curve corresponding to the smallest K value and mark it as the optimal temperature rise curve.

[0011] As a further solution of the present invention: the calculation process of the similarity value H is as follows: Obtain the stator winding temperature of the current synchronous permanent magnet motor at the end of the observation time T1 and mark it as t 末 , take the t 末 temperature as the initial temperature, the time period T2 as the extraction duration, extract the corresponding standard temperature rise curve from the standard temperature rise curve and mark it as the standard temperature rise curve A, divide the actual temperature rise curve B and the standard temperature rise curve A into multiple sub-curves at the same time interval, select the end point temperature data of each sub-curve and mark it as the comparison data, mark the total number of comparison data as n, construct the distance matrix between the actual temperature rise curve and the standard temperature rise curve according to the data corresponding to the n points, and the distance matrix is: ; where |Bn - An| is the difference distance value of the temperature data between the actual temperature rise curve B and the standard temperature rise curve A, construct a curve similarity function using the dynamic time warping method according to the distance matrix, and the formula of the curve similarity function is: H = ; where H is the similarity value between the actual temperature rise curve B and the standard temperature rise curve A.

[0012] As a further solution of the present invention: the process of adjusting the heat dissipation power is as follows: Based on the comparison data selected as described above, calculate the mean value V1 of the comparison data of the actual temperature curve and the mean value V2 of the comparison data of the standard temperature curve respectively. If V1 is greater than V2, increase the heat dissipation power of the heat dissipation device; if V1 is less than V2, decrease the heat dissipation power of the heat dissipation device.

[0013] As a further solution of the present invention: the specific adjustment process of the heat dissipation power is as follows: S1, calculate the absolute value of the difference between V1 and V2 and mark it as C, obtain the heat dissipation power P1 of the current high-speed synchronous permanent magnet motor heat dissipation device and the corresponding external load, extract the motor temperature rise curve S corresponding to the external load, and offset the extracted motor temperature rise curve with C as the offset value; S2, if increasing the heat dissipation power of the current motor heat dissipation device, the motor temperature rise curve shifts upward. Compare the shifted curve with the stator winding temperature rise curve Si under any load condition, and use the external load corresponding to the most similar temperature rise curve as the current motor's external load. Select the optimal heat dissipation power under the current external load condition and mark it as P2, and adjust the heat dissipation power of the current motor's heat dissipation device, P adjustment = P2 - P1; S3, if decreasing the heat dissipation power of the current motor heat dissipation device, the motor temperature rise curve shifts downward. Compare the shifted curve with the stator winding temperature rise curve under any load condition, and use the external load corresponding to the most similar temperature rise curve as the current motor's external load. Select the optimal heat dissipation power under the current external load condition and mark it as P2, and adjust the heat dissipation power of the current motor's heat dissipation device, P adjustment = P1 - P2.

[0014] The beneficial effects of the present invention: The present invention adjusts the magnitude of the external load connected to the high-speed synchronous permanent magnet motor at intervals, and obtains the stator winding temperature of the high-speed synchronous permanent magnet motor in real time, so as to obtain the temperature rise curve of the stator winding and the standard temperature rise curve of the stator winding under the optimal heat dissipation power of the high-speed permanent magnet motor under different external loads. The optimal temperature rise curve is selected from the temperature rise curves according to the actual stator winding temperature change curve, so as to select the heat dissipation power most suitable for the current load condition as the initial heat dissipation power of the current motor. The actual temperature rise curve of the motor after the heat dissipation device is turned on is obtained in real time and compared with the standard temperature rise curve for similarity. If the similarity value is less than the preset threshold, the heat dissipation power of the current heat dissipation device is adjusted. The present invention improves the working efficiency and reliability of the motor. By accurately selecting the temperature rise curve and the optimal heat dissipation power, the temperature of the motor stator winding can be effectively controlled, preventing the motor from being damaged or its performance from decreasing due to excessive temperature. Based on the difference in the temperature change curve, the change of the external load is judged, and the heat dissipation power of the heat dissipation device is dynamically adjusted, ensuring the heat dissipation requirements of the high-speed synchronous permanent magnet motor under different load conditions, reducing the energy consumption of the heat dissipation device, further optimizing the heat dissipation performance of the high-speed synchronous permanent magnet motor, and prolonging the service life of the high-speed synchronous permanent magnet motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Figure 1 It is a flow diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] Please refer to Figure 1 As shown, the present invention is a method for reducing the stator heating of a high-speed synchronous permanent magnet motor, which is characterized by including the following steps: S1. Adjust the magnitude of the external load connected to the high-speed synchronous permanent magnet motor at intervals, and obtain the stator winding temperature of the high-speed synchronous permanent magnet motor in real time; S2. Under any external load, without turning on the heat dissipation device, generate a curve of the stator winding temperature changing with time and mark it as the temperature rise curve Si, where i is a positive integer; S3. Under any external load, turn on the heat dissipation device, preset the initial heat dissipation power P0, and obtain the temperature of the stator winding of the high-speed synchronous permanent magnet motor in real time. If the temperature of the stator winding continues to change when it rises to the temperature limit, increase it gradually at the preset threshold on the basis of the initial heat dissipation power P0, and use the increased heat dissipation power as the new initial heat dissipation power and mark it as Pi. If at any initial heat dissipation power Pi, the temperature of the stator winding no longer changes when it rises to the temperature limit, record the heat dissipation power of the heat dissipation device at this time and mark it as the optimal heat dissipation power of this external load, and generate a curve of the temperature of the stator winding changing with time at the optimal heat dissipation power and mark it as the standard temperature rise curve Di; S4. In the actual environment, when the motor starts, preset the observation time T1, obtain the actual temperature rise curve of the stator winding within the observation time period T1, compare and screen the current actual temperature rise curve with the temperature rise curve Si, obtain the optimal temperature rise curve, use the external load corresponding to the optimal temperature rise curve as the current external load of the motor, turn on the motor heat dissipation device and select the optimal heat dissipation power of the current external load as the initial heat dissipation power; S5. Obtain the actual temperature rise curve of the motor within the time period T2 after the heat dissipation device is turned on in real time, and conduct a similarity comparison with the standard temperature rise curve to obtain the similarity value H. If the similarity value is less than the preset threshold, adjust the heat dissipation power of the current heat dissipation device. If the similarity value is greater than the preset threshold, keep the heat dissipation power of the current heat dissipation device.

[0019] In the present invention, by adjusting the size of the external load connected to the high-speed synchronous permanent magnet motor at intervals and obtaining the temperature of the stator winding of the high-speed synchronous permanent magnet motor in real time, the temperature rise curve of the stator winding and the standard temperature rise curve of the stator winding at the optimal heat dissipation power of the high-speed permanent magnet motor under different external loads are obtained. The optimal temperature rise curve is screened out from the temperature rise curves according to the actual temperature change curve of the stator winding, so as to select the heat dissipation power most suitable for the current load condition as the initial heat dissipation power of the current motor, and obtain the actual temperature rise curve of the motor in real time after the heat dissipation device is turned on, and conduct a similarity comparison with the standard temperature rise curve. If the similarity value is less than the preset threshold, the heat dissipation power of the current heat dissipation device is adjusted. The present invention improves the working efficiency and reliability of the motor. Through the accurate selection of the temperature rise curve and the optimal heat dissipation power, the temperature of the stator winding of the motor can be effectively controlled, preventing the motor from being damaged or its performance from deteriorating due to excessive temperature, and judging the change of the external load based on the difference of the temperature change curve, dynamically adjusting the heat dissipation power of the heat dissipation device, ensuring the heat dissipation requirements of the high-speed synchronous permanent magnet motor under different load conditions, reducing the energy consumption of the heat dissipation device, further optimizing the heat dissipation performance of the high-speed synchronous permanent magnet motor, and prolonging the service life of the high-speed synchronous permanent magnet motor.

[0020] In a preferred case of this embodiment, the process of obtaining the temperature of the stator winding is as follows: The stator winding temperature data is obtained at different windings of the stator core through a temperature sensor, the average value of the temperature data of each stator winding is calculated to obtain the average temperature, and according to the observation time and the average temperature, a curve of the change of the average temperature with time is generated with time as the abscissa and the average temperature as the ordinate.

[0021] By obtaining the stator winding temperature data at different windings of the stator core through a temperature sensor and calculating the average temperature of each stator winding, the temperature change of the motor stator winding can be more accurately reflected.

[0022] In another preferred case of this embodiment, the temperature sensors are evenly distributed on the stator core at different windings along the stator core, and several of the temperature sensors are evenly distributed on each stator winding.

[0023] In a preferred case of this embodiment, the generation process of the standard temperature rise curve Di is as follows: Under any external load, the corresponding optimal power under the corresponding load is selected as the initial heat dissipation power for motor starting, and the stator winding temperature of the high-speed synchronous permanent magnet motor is obtained in real time. When the stator winding temperature reaches the temperature limit, a curve of the change of the stator winding temperature with time is generated with time as the abscissa and the stator winding temperature as the ordinate and marked as the standard temperature rise curve.

[0024] Under different external load conditions of the high-speed synchronous permanent magnet motor, the heat generated per unit time is different. Therefore, when the external load is kept unchanged, the standard temperature rise curve is generated. Since the heat dissipation of the motor not only depends on the heat dissipation device, but the motor itself also dissipates heat to the external environment. The higher the internal heat of the motor, the faster the heat dissipation efficiency of the motor to the external environment. Considering that there is a limit value for the stator temperature of the motor, when the stator temperature of the motor reaches the limit value, the heat dissipation power of the motor reaches the ideal maximum, and the heat dissipation power required by the heat dissipation device can also be minimized ideally. Therefore, when the motor starts, the optimal heat dissipation power of the heat dissipation device cannot completely take away the heat generated by the motor, and the motor temperature will slowly rise. When the stator temperature limit of the motor is reached, the heat dissipation device can keep the stator temperature of the motor unchanged, which not only ensures that the internal stator of the motor is always within the safe temperature range during operation, but also can reduce the energy consumption of the heat dissipation device.

[0025] In a preferred case of this embodiment, the obtaining process of the optimal temperature rise curve is as follows: Obtain the stator winding temperature at the moment before the motor starts and mark it as t 初 , with the t 初Taking the temperature as the initial temperature and the time period T1 as the extraction duration, intercept the corresponding curve segment from the temperature rise curve Si under any load and mark it as the comparison temperature rise curve. Obtain several comparison temperature rise curves, construct a fitting function Y = KX + L to fit all the comparison temperature rise curves, and obtain the values of K and L by the least squares method. Calculate the difference between the K value of any comparison temperature rise curve and the K1 value of the current actual temperature rise curve, select the K value with the smallest difference from K1, and select the comparison temperature rise curve corresponding to the smallest K value and mark it as the optimal temperature rise curve.

[0026] In a preferred case of this embodiment, the calculation process of the similarity value H is as follows: Obtain the stator winding temperature of the current synchronous permanent magnet motor at the end of the observation time T1 and mark it as t 末 , taking the t 末 temperature as the initial temperature and the time period T2 as the extraction duration, extract the corresponding standard temperature rise curve from the standard temperature rise curve and mark it as the standard temperature rise curve A. Divide the actual temperature rise curve B and the standard temperature rise curve A into multiple sub-curves at the same time interval, select the endpoint temperature data of each sub-curve and mark it as the comparison data, mark the total number of comparison data as n, and construct the distance matrix between the actual temperature rise curve and the standard temperature rise curve according to the data corresponding to the n points. The distance matrix is: ; where |Bn - An| is the difference distance value between the temperature data of the actual temperature rise curve B and the standard temperature rise curve A. Construct a curve similarity function using the dynamic time warping method according to the distance matrix. The formula of the curve similarity function is: H = ; where H is the similarity value between the actual temperature rise curve B and the standard temperature rise curve A.

[0027] By calculating the distance matrix and constructing a curve similarity function using the dynamic time warping method, the similarity between the actual temperature rise curve and the standard temperature rise curve can be effectively evaluated. According to the preset threshold of the curve comparison similarity value, it can be determined whether the external load of the current motor has changed, which helps to adjust the heat dissipation power of the heat dissipation device in advance.

[0028] In a preferred case of this embodiment, the process of adjusting the heat dissipation power is as follows: According to the selected comparison data described above, calculate the mean value V1 of the comparison data of the actual temperature curve and the mean value V2 of the comparison data of the standard temperature curve respectively. If V1 is greater than V2, increase the heat dissipation power of the heat dissipation device; if V1 is less than V2, decrease the heat dissipation power of the heat dissipation device.

[0029] If V1 is greater than V2, it indicates that the heat generated by the motor per unit time is greater than the predicted heat generation, thus determining that the actual load of the motor has increased. Therefore, it is necessary to increase the heat dissipation power of the heat dissipation device. If V1 is less than V2, it indicates that the heat generated by the motor per unit time is less than the predicted heat generation, thus determining that the actual load of the motor has increased. Therefore, it is necessary to reduce the heat dissipation power of the heat dissipation device.

[0030] In another preferred case of this embodiment, the specific adjustment process of the heat dissipation power is as follows: S1. Calculate the absolute value of the difference between V1 and V2 and label it as C. Obtain the heat dissipation power P1 of the heat dissipation device of the current high-speed synchronous permanent magnet motor and the corresponding external load. Extract the motor temperature rise curve S corresponding to the external load. Offset the extracted motor temperature rise curve with C as the offset value. S2. If the heat dissipation power of the current motor heat dissipation device is increased, the motor temperature rise curve shifts upward. Compare the shifted curve with the stator winding temperature rise curve Si under any load condition. Take the external load corresponding to the most similar temperature rise curve as the external load of the current motor. Select the optimal heat dissipation power under the current external load condition and label it as P2. Adjust the heat dissipation power of the heat dissipation device of the current motor, P adjustment = P2 - P1. S3. If the heat dissipation power of the current motor heat dissipation device is reduced, the motor temperature rise curve shifts downward. Compare the shifted curve with the stator winding temperature rise curve under any load condition. Take the external load corresponding to the most similar temperature rise curve as the external load of the current motor. Select the optimal heat dissipation power under the current external load condition and label it as P2. Adjust the heat dissipation power of the heat dissipation device of the current motor, P adjustment = P1 - P2.

[0031] Assume that the predicted external load of the current motor is W1, and select the optimal heat dissipation power P1 corresponding to W1 as the heat dissipation power of the current motor. In real life, the external load of the motor has changed significantly, so that the heat generation power per unit time is also changing. Assume that the original heat generation power of the motor is 15W, and the heat dissipation temperature with the external environment when the motor stator temperature reaches the limit is 5W. At this time, the optimal heat dissipation power is 10W. If the actual heat generation efficiency of the motor changes to 20W, when dissipating heat with the optimal heat dissipation power of 10W, it is equivalent to dissipating 5W less heat per second, which is transformed into the current absolute value of the temperature difference C. Therefore, extract the motor temperature rise curve S corresponding to the external load, offset the extracted motor temperature rise curve with C as the offset value, and find the external load corresponding to the temperature rise curve most similar to the offset motor temperature rise curve from the temperature rise curves Si as the external load of the current motor. Select the optimal heat dissipation power under the current external load condition and label it as P2, and adjust the current motor power to P2.

[0032] As a practical example of the present invention: In actual production, a high-speed permanent magnet synchronous motor needs to be connected to a frequency converter to adjust the input voltage at the motor end. By precisely controlling the voltage at the motor end, the current input to the stator region is controlled to achieve precise control of the motor speed and torque. The frequency converter and the motor are connected by a cable. Due to the influence of various distributed parameters in the cable, such as cable length, resistance, etc., a traveling wave reflection phenomenon will occur at the permanent magnet synchronous motor end, resulting in an overvoltage more than twice at the motor end, causing the input voltage of the motor to be too high, the actual input current to be greater than the rated current of the motor, and serious motor heating, resulting in abnormal temperature rise of the motor. The intermediate frequency reactor of the PMSL series can limit the voltage change rate, reduce the amplitude of high-order harmonics and the ripple current input to the motor end, thereby reducing the copper loss and iron loss of the motor. Therefore, in actual production, an intermediate frequency reactor of the PMSL series is usually installed at the output end of the frequency converter. The present invention is based on the regulation of the heat dissipation device of the high-speed synchronous permanent magnet motor after installing the intermediate frequency reactor of the PMSL series at the output end of the frequency converter, realizing the optimization of the voltage transmission and heat dissipation device of the high-speed synchronous permanent magnet motor, thereby improving the overall performance and reliability of the motor.

[0033] The above has described in detail an embodiment of the present invention, but the content described is only a preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. Any equivalent changes and improvements made according to the scope of the present invention application shall still fall within the scope covered by the patent of the present invention.

Claims

1. A method for reducing stator heating of a high-speed synchronous permanent magnet motor, characterized in that: The following steps are involved: S1, adjusting the size of the external load connected to the high-speed synchronous permanent magnet motor at intervals, and obtaining the stator winding temperature of the high-speed synchronous permanent magnet motor in real time; S2, under any external load, without turning on the heat dissipation device, a curve of stator winding temperature change over time is generated and marked as temperature rise curve Si, where i is a positive integer; S3, under any external load, turn on the heat dissipation device, preset the initial heat dissipation power P0, obtain the stator winding temperature of the high-speed synchronous permanent magnet motor in real time, if the temperature of the stator winding continues to change when the temperature rises to the temperature limit, then gradually increase the initial heat dissipation power P0 with a preset threshold, and use the increased heat dissipation power as the new initial heat dissipation power and mark it as Pi, if there is any initial heat dissipation power Pi, when the temperature of the stator winding rises to the temperature limit, the temperature no longer changes, record the heat dissipation power of the heat dissipation device at this time and mark it as the optimal heat dissipation power of the external load, and generate a curve of the stator winding temperature change over time at the optimal heat dissipation power and mark it as the standard temperature rise curve Di; S4, in an actual environment, when the motor is started, preset an observation time T1, obtain the actual temperature rise curve of the stator winding within the observation time period T1, compare and screen the current actual temperature rise curve with the temperature rise curve Si, obtain the optimal temperature rise curve, use the external load corresponding to the optimal temperature rise curve as the external load of the current motor, turn on the motor heat dissipation device and select the optimal heat dissipation power of the current external load as the initial heat dissipation power; S5, real-time acquisition of the actual temperature rise curve of the motor in time period T2 after the heat dissipation device is turned on, and comparison with the standard temperature rise curve to obtain a similarity value H. If the similarity value is less than a preset threshold, the heat dissipation power of the current heat dissipation device is adjusted; if the similarity value is greater than the preset threshold, the heat dissipation power of the current heat dissipation device is maintained.

2. A method for reducing stator heating of a high-speed synchronous permanent magnet motor according to claim 1, characterized in that: The process of obtaining the stator winding temperature is as follows: The temperature data of the stator windings are obtained at different windings of the stator core by using a temperature sensor, and the average value of the temperature data of each stator winding is calculated to obtain the average temperature. According to the observation time and the average temperature, a temperature variation curve with time is generated with the time as the horizontal axis and the average temperature as the vertical axis.

3. A method for reducing stator heating of a high-speed synchronous permanent magnet motor according to claim 2, characterized in that: The temperature sensors are evenly distributed along the stator core at different windings on the stator core, and a plurality of the temperature sensors are evenly distributed on each stator winding.

4. A method for reducing stator heating of a high-speed synchronous permanent magnet motor according to claim 1, characterized in that The generation process of the standard temperature rise curve Di is as follows: Under any external load, the optimal power corresponding to the corresponding load is selected as the initial heat dissipation power for motor startup and the stator winding temperature of the high-speed synchronous permanent magnet motor is obtained in real time. A temperature change curve with time as the horizontal coordinate and the stator winding temperature as the vertical coordinate is generated and marked as a standard temperature rise curve.

5. The method for reducing stator heating of a high-speed synchronous permanent magnet motor according to claim 1, characterized in that: The process of obtaining the optimal temperature rise curve is as follows: Get the stator winding temperature just before the motor starts and mark it as t 初 , with the t 初 Temperature is used as the initial temperature, time period T1 is used as the extraction duration, and the corresponding curve segment is intercepted from the temperature rise curve Si under any load and marked as a comparative temperature rise curve to obtain several comparative temperature rise curves. A fitting function Y=KX+L is constructed to fit all comparative temperature rise curves, and the values ​​of K and L are obtained by the least squares method. The difference between the K value of any comparative temperature rise curve and the current actual temperature rise curve K1 is calculated, and the K value with the smallest difference with K1 is selected. The comparative temperature rise curve corresponding to the minimum K value is selected and marked as the optimal temperature rise curve.

6. The method for reducing stator heating of a high-speed synchronous permanent magnet motor according to claim 1, characterized in that: The calculation process of the similarity value H is: Get the stator winding temperature of the current synchronous permanent magnet motor at the end of observation time T1 and mark it as t 末 , with the t 末 The temperature is taken as the initial temperature, the time period T2 is taken as the extraction duration, the corresponding standard temperature rise curve is intercepted from the standard temperature rise curve and marked as the standard temperature rise curve A, the actual temperature rise curve B and the standard temperature rise curve A are divided into multiple sub-curves according to the same time interval, the endpoint temperature data of each sub-curve is selected and marked as the comparison data, the total number of comparison data is marked as n, and the distance matrix between the actual temperature rise curve and the standard temperature rise curve is constructed according to the data corresponding to the n points. The distance matrix is: ; Where |Bn-An| is the difference distance value between the temperature data of the actual temperature rise curve B and the standard temperature rise curve A. The curve similarity function is constructed using the dynamic time warping method based on the distance matrix. The curve similarity function formula is: H= ； Wherein, H is the similarity value between the actual temperature rise curve B and the standard temperature rise curve A.

7. The method for reducing stator heating of a high-speed synchronous permanent magnet motor according to claim 1, characterized in that: The process of adjusting the heat dissipation power is as follows: According to the selected comparison data, the comparison data mean V1 of the actual temperature curve and the comparison data mean V2 of the standard temperature curve are calculated respectively. If V1 is greater than V2, the heat dissipation power of the heat dissipation device is increased; if V1 is less than V2, the heat dissipation power of the heat dissipation device is reduced.

8. The method for reducing stator heating of a high-speed synchronous permanent magnet motor according to claim 7, characterized in that: The specific adjustment process of heat dissipation power is as follows: S1, calculate the absolute value of the difference between V1 and V2 and mark it as C, obtain the heat dissipation power P1 of the current high-speed synchronous permanent magnet motor heat dissipation device and the corresponding external load, extract the motor temperature rise curve S corresponding to the external load, and use C as the offset value to offset the extracted motor temperature rise curve; S2, if the heat dissipation power of the current motor heat dissipation device is increased, the motor temperature rise curve is shifted upward, and the shifted curve is compared with the stator winding temperature rise curve Si under any load condition, and the external load corresponding to the most similar temperature rise curve is used as the external load of the current motor, and the best heat dissipation power under the current external load condition is selected and marked as P2, and the heat dissipation power of the heat dissipation device of the current motor is adjusted, P adjustment = P2-P1; S3, if the heat dissipation power of the current motor heat dissipation device is reduced, the motor temperature rise curve will be shifted downward, and the shifted curve will be compared with the stator winding temperature rise curve under any load condition, and the external load corresponding to the most similar temperature rise curve will be used as the external load of the current motor, and the best heat dissipation power under the current external load condition will be selected and marked as P2, and the heat dissipation power of the heat dissipation device of the current motor will be adjusted, P adjustment = P1-P2.

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