Motor rotor temperature determination method and device, computer equipment, readable storage medium and program product

Abstract

The invention relates to a motor rotor temperature determination method and device, computer equipment, a computer readable storage medium and a computer program product. The method comprises the following steps: acquiring a first back electromotive force of a motor; inputting the first back electromotive force into a second-order generalized integrator for processing to obtain a first flux linkage value of a motor stator flux linkage; determining a flux linkage null drift value, and obtaining a second flux linkage value of the motor stator flux linkage based on the first flux linkage value and the flux linkage null drift value; obtaining a target flux linkage value of the motor rotor flux linkage based on the second flux linkage value; and obtaining a target rotor temperature based on the target flux linkage value and a preset corresponding relationship between the flux linkage value of the motor rotor flux linkage and the motor rotor temperature. The method can reduce the manufacturing cost of the motor and the fault rate of the terminal.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a method, device, computer equipment, computer-readable storage medium and computer program product for determining the temperature of a motor rotor. Background Art

[0002] Motors (such as permanent magnet synchronous motors (PMSM)) are widely used in electric vehicles, military and other fields due to their small size, high power density and high efficiency. In the control process of the motor, obtaining accurate motor rotor temperature is of great significance to the control performance. If the motor rotor temperature is too high and exceeds a certain limit, the motor rotor will be irreversibly demagnetized, which will seriously affect the motor performance and make the motor risky to use. In addition, as the motor rotor temperature increases, the motor output torque will also deviate.

[0003] At present, the main method for obtaining the rotor temperature of the motor is direct detection. By pre-burying the temperature sensor in the motor rotor, the real-time reliable transmission of the rotor temperature is realized. However, this method requires the modification of the motor structure, which increases the manufacturing cost of the motor and brings a higher failure rate to the terminal where the motor is located. Alternatively, the temperature is mainly obtained through thermal network analysis and calculation, the motor is subdivided into units, the thermal resistance between the units is established and a thermal network model is formed. However, this method has a very large dependence on the model parameters, which affects the accuracy of the temperature estimation, and the theoretical analysis of temperature estimation is complex. Summary of the invention

[0004] Based on this, it is necessary to provide a method, device, computer equipment, computer-readable storage medium and computer program product for determining the motor rotor temperature, which can reduce the motor manufacturing cost and the terminal failure rate, improve the temperature estimation accuracy and simplify the temperature estimation algorithm in order to solve the above technical problems.

[0005] In a first aspect, the present application provides a method for determining the temperature of a motor rotor, the method comprising:

[0006] Obtain the first back electromotive force of the motor;

[0007] Inputting the first back electromotive force into a second-order generalized integrator for processing to obtain a first flux value of the motor stator flux;

[0008] Determine a flux zero drift value, and obtain a second flux value of the motor stator flux based on the first flux value and the flux zero drift value;

[0009] Based on the second flux value, obtaining a target flux value of the motor rotor flux;

[0010] Based on the target flux value and a corresponding relationship between a preset flux value of the motor rotor flux and the motor rotor temperature, a target rotor temperature is obtained.

[0011] In one embodiment, obtaining a first back electromotive force of the motor includes:

[0012] Obtaining three-phase voltage values ​​and three-phase current values ​​of the motor;

[0013] Based on the three-phase voltage values, voltage values ​​under coordinate axes in a two-phase stationary coordinate system are obtained;

[0014] Based on the three-phase current values, current values ​​under coordinate axes in the two-phase stationary coordinate system are obtained;

[0015] The first back electromotive force is obtained based on the voltage value and the current value.

[0016] In one embodiment, determining the flux zero drift value includes:

[0017] Determining a maximum value and a minimum value of the stator flux of the motor;

[0018] The flux zero drift value is determined based on the maximum flux value and the minimum flux value.

[0019] In one embodiment, determining the maximum value of the stator flux of the motor includes:

[0020] Obtaining the current moment flux value of the motor stator flux;

[0021] Determining whether the flux value at the current moment is greater than a preset maximum flux value of the motor stator flux;

[0022] If yes, the current magnetic flux value is used as the maximum magnetic flux value to update the maximum magnetic flux value, and the number of cycles is increased to obtain the current number of cycles;

[0023] If not, increase the initial loop count to get the current loop count;

[0024] Determine whether the current number of cycles is not less than a preset number threshold;

[0025] If so, output the maximum value of the magnetic flux;

[0026] If not, the current number of cycles is taken as the initial number of cycles, and within the sampling period, the flux value of the motor stator flux at the next moment is obtained as the flux value at the current moment, and the step of returning to determine whether the flux value at the current moment is greater than the preset maximum flux value of the motor stator flux is continued until the maximum flux value is output.

[0027] In one embodiment, determining the minimum value of the stator flux of the motor includes:

[0028] Obtaining the current moment flux value of the motor stator flux;

[0029] Determining whether the current flux value is less than a preset minimum flux value of the motor stator flux;

[0030] If yes, the current magnetic flux value is used as the minimum magnetic flux value to update the minimum magnetic flux value, and the number of cycles is increased to obtain the current number of cycles;

[0031] If not, increase the initial loop count to get the current loop count;

[0032] Determine whether the current number of cycles is not less than a preset number threshold;

[0033] If so, output the minimum value of the magnetic flux;

[0034] If not, the current number of cycles is taken as the initial number of cycles, and within the sampling period, the flux value of the motor stator flux at the next moment is obtained as the flux value at the current moment, and the step of returning to determine whether the flux value at the current moment is less than the preset minimum flux value of the motor stator flux is continued until the minimum flux value is output.

[0035] In one embodiment, obtaining a target flux value of the motor rotor flux based on the second flux value includes:

[0036] Determine a coordinate magnetic flux value of the second magnetic flux value under a target coordinate axis in a target coordinate system;

[0037] Obtaining the inductance flux value of the motor under the target coordinate axis;

[0038] The target flux value is determined based on the coordinate flux value and the inductance flux value.

[0039] In one embodiment, the process of constructing the corresponding relationship includes:

[0040] For each sampled temperature value among the multiple sampled temperature values, obtain the no-load back electromotive force sampled respectively under the current sampled temperature value condition and under the multiple speed conditions of the motor; based on each speed condition and the no-load back electromotive force corresponding to each speed condition, obtain the corresponding flux value of the motor rotor flux, calculate the average value of the flux values ​​of the motor rotor flux corresponding to the multiple speed conditions, and obtain the flux value of the motor rotor flux under the current sampled temperature value condition;

[0041] The corresponding relationship is constructed based on a plurality of sampling temperature value conditions and the flux linkage values ​​of the motor rotor flux linkage respectively corresponding to the sampling temperature value conditions.

[0042] In a second aspect, the present application further provides a device for determining the temperature of a motor rotor, the device comprising:

[0043] An acquisition module, used for acquiring a first back electromotive force of the motor;

[0044] A processing module, used for inputting the first back electromotive force into a second-order generalized integrator for processing to obtain a first flux value of the motor stator flux;

[0045] A first determination module, configured to determine a flux zero drift value, and obtain a second flux value of a stator flux of a motor based on the first flux value and the flux zero drift value;

[0046] A second determination module is used to obtain a target flux value of the motor rotor flux based on the second flux value;

[0047] The third determination module is used to obtain the target rotor temperature based on the target flux value and the corresponding relationship between the preset flux value of the motor rotor flux and the motor rotor temperature.

[0048] In a third aspect, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method of each embodiment when executing the computer program.

[0049] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the method of each embodiment when executed by a processor.

[0050] In a fifth aspect, the present application also provides a computer program product, including a computer program, which implements the steps of the methods of each embodiment when executed by a processor.

[0051] The above-mentioned method, device, computer equipment, computer-readable storage medium and computer program product for determining the temperature of the motor rotor only need to obtain the first back electromotive force of the motor, input the first back electromotive force into a second-order generalized integrator for processing, obtain the first flux value of the motor stator flux, determine the flux zero drift value, and obtain the second flux value of the motor stator flux based on the first flux value and the flux zero drift value, obtain the target flux value of the motor rotor flux based on the second flux value, and obtain the target rotor temperature based on the target flux value and the correspondence between the preset flux value of the motor rotor flux and the motor rotor temperature, without burying a temperature sensor in the motor rotor, and the target rotor temperature can be obtained, thereby reducing the manufacturing cost of the motor and the failure rate of the terminal. At the same time, compared with the method of obtaining temperature by network analysis calculation, the estimation process is simpler than the thermal network analysis method, and does not depend on model parameters, thereby improving the accuracy of temperature calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0053] FIG1 is a schematic flow chart of a method for determining the temperature of a motor rotor in one embodiment;

[0054] Figure 2 is a schematic diagram of the improved SOGI;

[0055] Figure 3 A schematic diagram of a process of performing zero drift correction using an average value method in an embodiment;

[0056] Figure 4 A process for determining a maximum value of a magnetic flux by a maximum value obtaining module in one embodiment;

[0057] Figure 5 A process for determining a minimum value of a magnetic flux by a minimum value obtaining module in one embodiment;

[0058] Figure 6 is a schematic flow chart of a method for determining the temperature of a motor rotor in another embodiment;

[0059] Figure 7 It is a schematic diagram of the corresponding relationship between the magnetic flux value of the rotor magnetic flux and the motor rotor temperature;

[0060] Figure 8 It is a structural schematic diagram of a device for determining the temperature of a motor rotor;

[0061] Fig. 9 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0063] In one embodiment, as shown in FIG1 , a method for determining the temperature of a motor rotor is provided. This embodiment is illustrated by applying the method to a terminal. It is understandable that the method can also be applied to a server, or to a system including a terminal and a server, and is implemented through the interaction between the terminal and the server. In this embodiment, the method includes the following steps:

[0064] Step 102, obtaining a first back electromotive force of the motor;

[0065] Step 104, inputting the first back electromotive force into a second-order generalized integrator for processing to obtain a first flux value of the motor stator flux;

[0066] Since the traditional pure integrator observer can easily introduce integral initial value error and DC bias when calculating the flux, which eventually leads to integrator saturation and affects the accuracy of the flux result, this application adopts a second-order general integrator (SOGI) as the stator flux observer to avoid integral saturation and improve observation performance.

[0067] Step 106, determining a flux zero drift value, and obtaining a second flux value of the motor stator flux based on the first flux value and the flux zero drift value;

[0068] In the present application, at a certain moment, the first back electromotive force is input into a second-order generalized integrator for processing to obtain a first flux value of the motor stator flux. At multiple moments after this moment, the first back electromotive force is input into a second-order generalized integrator for processing to obtain the flux values ​​of the motor stator flux. The flux values ​​of the motor stator flux at these multiple moments are sampled, and the flux zero drift value is determined based on the sampled flux values.

[0069] The difference between the first flux linkage value and the flux linkage zero drift value is calculated to obtain a second flux linkage value of the motor stator flux linkage.

[0070] Since the traditional SOGI can only suppress the zero drift of the back electromotive force but cannot completely eliminate it, the present application determines the flux zero drift value and obtains the second flux value of the motor stator flux based on the first flux value and the flux zero drift value, which can eliminate the flux zero drift. This is combined with the traditional SOGI to form the improved SOGI used in the present application, which further improves the accuracy of stator flux observation.

[0071] Step 108: obtaining a target flux value of the motor rotor flux based on the second flux value;

[0072] Step 110 : Obtain a target rotor temperature based on the target flux value and a preset correspondence between the flux value of the motor rotor flux and the motor rotor temperature.

[0073] In this embodiment, the flux value of the motor rotor flux has a one-to-one correspondence with the motor rotor temperature, and the one-to-one correspondence is pre-constructed.

[0074] Based on the corresponding relationship, a target rotor temperature corresponding to the target flux value is determined from the corresponding relationship.

[0075] In this embodiment, it is only necessary to obtain the first back electromotive force of the motor, input the first back electromotive force into a second-order generalized integrator for processing, obtain the first flux value of the motor stator flux, determine the flux zero drift value, and obtain the second flux value of the motor stator flux based on the first flux value and the flux zero drift value, and obtain the target flux value of the motor rotor flux based on the second flux value. The target rotor temperature can be obtained based on the target flux value and the correspondence between the preset flux value of the motor rotor flux and the motor rotor temperature, without burying a temperature sensor in the motor rotor, and the target rotor temperature can be obtained, thereby reducing the manufacturing cost of the motor and the failure rate of the terminal. At the same time, compared with the method of obtaining temperature by network analysis calculation, the estimation process is simpler than the thermal network analysis method, and does not depend on model parameters, thereby improving the accuracy of temperature calculation.

[0076] In one embodiment, obtaining the first back electromotive force of the motor includes: obtaining the three-phase voltage value and the three-phase current value of the motor; obtaining the voltage value under the coordinate axis in the two-phase stationary coordinate system based on the three-phase voltage value; obtaining the current value under the coordinate axis in the two-phase stationary coordinate system based on the three-phase current value; and obtaining the first back electromotive force based on the voltage value and the current value.

[0077] The real-time value of the voltage sensor is collected through the sampling circuit to obtain the three-phase voltage value of the motor in the current state. The real-time value of the current sensor is collected through the sampling circuit to obtain the three-phase current value of the motor in the current state. The three-phase voltage value includes , the three-phase current values ​​include .

[0078] Through coordinate transformation, the three-phase voltage value is converted into the voltage value under the coordinate axis in the two-phase stationary coordinate system. The coordinate axis in the two-phase stationary coordinate system includes Axis and Axis, calculated as follows:

[0079] ; and In the two-phase stationary coordinate system Axis and The voltage value of the shaft;

[0080] Through coordinate transformation, the three-phase current value is converted into the current value under the coordinate axis in the two-phase stationary coordinate system. The coordinate axis in the two-phase stationary coordinate system includes Axis and Axis, calculated as follows:

[0081] ; and In the two-phase stationary coordinate system Axis and The current value of the shaft;

[0082] In the above formula, Represents the coordinate transformation matrix, and its specific form is as follows:

[0083] ;

[0084] Based on the voltage equation of PMSM, calculate the first back electromotive force in the current state, specifically:

[0085] The voltage equation of PMSM in two-phase stationary coordinates is: ;

[0086] Thus, the first back electromotive force is obtained : ; Among them, RS is the stator resistance of the motor.

[0087] Reference Figure 2 In one embodiment, the first back electromotive force is input into a second-order generalized integrator for processing to obtain a first flux value of the motor stator flux, specifically including:

[0088] First, determine the input signal and final output signal of the improved SOGI: the input signal is the back EMF (corresponding to E1 in the figure), the final output signal is the second flux value Based on the input signal , the transfer function of the traditional SOGI is designed in sequence, the second back EMF With input signal The transfer function is formula 1: ; Output signal With input signal The transfer function is formula 2: Based on formula 1 and formula 2, the first flux value of the motor stator flux is obtained With input signal The transfer function is formula 3: ;

[0089] In one of the embodiments, determining the flux zero drift value includes: determining a maximum flux value and a minimum flux value of the motor stator flux; and determining the flux zero drift value based on the maximum flux value and the minimum flux value.

[0090] Assume that the first back electromotive force is input into a second-order generalized integrator for processing, and the moment when the first flux value of the motor stator flux is obtained is the first moment. At multiple moments after the first moment (the multiple moments are all within the sampling period), the first back electromotive force is respectively input into the second-order generalized integrator for processing to obtain the flux values ​​of the motor stator flux. The flux values ​​of the motor stator flux at these multiple moments are sampled, and the maximum flux value and the minimum flux value of the motor stator flux are determined based on the sampled flux values. The average of the maximum flux value and the minimum flux value is determined, and the average value is used as the flux zero drift value.

[0091] Then refer to Figure 2 Schematic diagram of the improved SOGI, the first magnetic flux value is obtained After subtraction, the final second stator flux can be obtained , refer to the following formula: ;in, ;in, is the maximum value of magnetic flux, is the minimum value of magnetic linkage.

[0092] In this embodiment, the process of performing zero drift correction using the average value method is as follows: Figure 3 As shown. In the first back EMF After the initial value of the stator flux is obtained through integration (i.e., the first flux value of the stator flux of the above motor), In the coordinate system, the maximum value of the flux amplitude within a sinusoidal cycle is obtained through the maximum value obtaining module, and the minimum value of the flux amplitude within a sinusoidal cycle is obtained through the minimum value obtaining module. Then, the maximum and minimum values ​​are averaged, and the integral zero drift value is output. After passing through a low-pass filter, the current flux zero drift value can be obtained, which is recorded as , the initial value of the stator flux minus the flux zero drift value can be obtained to obtain the second flux value of the motor stator flux that eliminates the flux zero drift. (Corresponding to the output of the second stator flux in the figure).

[0093] In this embodiment, an improved second-order generalized integrator based on the average value method can be used to estimate the flux value of the motor stator flux, eliminate the flux zero drift caused by DC bias, overcome the integral saturation problem of the traditional pure integrator, and improve the accuracy of flux estimation.

[0094] Reference Figure 4 The maximum value obtaining module determines the maximum value of the flux linkage. The maximum value of the flux linkage of the motor stator can be determined by the maximum value obtaining module. The specific operation process is as follows:

[0095] In one of the embodiments, determining the maximum flux value of the motor stator flux includes: obtaining the current moment flux value of the motor stator flux; judging whether the current moment flux value is greater than a preset, maximum flux value of the motor stator flux; if so, taking the current moment flux value as the maximum flux value to update the maximum flux value, and increasing the number of cycles to obtain the current number of cycles; if not, increasing the initial number of cycles to obtain the current number of cycles; judging whether the current number of cycles is not less than a preset number threshold; if so, outputting the maximum flux value; if not, taking the current number of cycles as the initial number of cycles, and within the sampling period, obtaining the flux value of the motor stator flux at the next moment as the current moment flux value, returning to the step of judging whether the current moment flux value is greater than the preset, maximum flux value of the motor stator flux, and continuing to execute until the maximum flux value is output.

[0096] Set the cycle number threshold, that is, the above-mentioned preset number threshold. Generally, the cycle number threshold is the number of sampling points in a sine cycle, which is related to the sampling rate and carrier frequency. Set the initial value of the cycle number to 0, and set the initial maximum value variable of the motor stator flux to 0.

[0097] First, after the sampling period within a sinusoidal cycle arrives, the current moment flux value of the motor stator flux is obtained (corresponding to the figure to obtain and store the current stator flux value). For example, the sinusoidal cycle is set to 1s and the sampling period is 1ms, that is, the flux value of the motor stator flux is sampled every 1ms;

[0098] Determine whether the current flux value (corresponding to the current value in the figure) is greater than the preset maximum flux value variable. If the current flux value is greater than the preset maximum flux value variable, assign the current flux value to the maximum flux value variable and increase the number of loops by 1. If the current flux value is not greater than the preset maximum flux value variable, increase the number of loops by 1.

[0099] Determine whether the number of cycles is greater than or equal to the cycle number threshold. If so, output the maximum flux value. If not, update the initial number of cycles, and obtain the flux value of the motor stator flux in the next sampling period (the next 1ms) as the current flux value. Return to the step of determining whether the current flux value is greater than the preset maximum flux value of the motor stator flux and continue to execute until the maximum flux value is output.

[0100] Or determine whether the number of cycles is greater than or equal to the cycle number threshold. If so, output the maximum flux value. If not, update the initial number of cycles. After the next sampling period arrives, return to the step of obtaining and storing the current stator flux value and continue to execute until the maximum flux value is output.

[0101] Reference Figure 5 This is a process of determining the minimum value of flux linkage by a minimum value obtaining module in an embodiment. The minimum value obtaining module can be used to determine the minimum value of flux linkage of the motor stator. The specific operation process of the minimum value obtaining module is as follows:

[0102] In one of the embodiments, determining the minimum flux value of the motor stator flux includes: obtaining the current moment flux value of the motor stator flux; judging whether the current moment flux value is less than a preset, minimum flux value of the motor stator flux; if so, taking the current moment flux value as the minimum flux value to update the minimum flux value, and increasing the number of cycles to obtain the current number of cycles; if not, increasing the initial number of cycles to obtain the current number of cycles; judging whether the current number of cycles is not less than a preset number threshold; if so, outputting the minimum flux value; if not, taking the current number of cycles as the initial number of cycles, and within the sampling period, obtaining the flux value of the motor stator flux at the next moment as the flux value at the current moment, returning to the step of judging whether the current moment flux value is less than the preset, minimum flux value of the motor stator flux, and continuing to execute until the minimum flux value is output.

[0103] Set the cycle number threshold, that is, the above-mentioned preset number threshold. Generally, the cycle number threshold is the number of sampling points in a sine cycle, which is related to the sampling rate and carrier frequency; set the initial value of the cycle number to 0; set the initial minimum value variable of the motor stator flux to 0;

[0104] First, after the sampling period within a sinusoidal cycle arrives, the current moment flux value of the motor stator flux is obtained (corresponding to the figure to obtain and store the current stator flux value). For example, the sinusoidal cycle is set to 1s and the sampling period is 1ms, that is, the flux value of the motor stator flux is sampled every 1ms;

[0105] Determine whether the current magnetic flux value (corresponding to the current value in the figure) is less than the preset magnetic flux minimum value variable. If the current magnetic flux value is less than the preset magnetic flux minimum value variable, the current magnetic flux value is assigned to the magnetic flux minimum value variable, and the number of loops increases by 1. If the current magnetic flux value is not less than the preset magnetic flux minimum value variable, the number of loops increases by 1.

[0106] Determine whether the number of cycles is greater than or equal to the cycle number threshold. If so, output the minimum flux value. If not, update the initial number of cycles, and obtain the flux value of the motor stator flux in the next sampling period (the next 1ms) as the flux value at the current moment. Return to the step of determining whether the flux value at the current moment is less than the preset minimum flux value of the motor stator flux and continue to execute until the minimum flux value is output.

[0107] Or determine whether the number of cycles is greater than or equal to the cycle number threshold. If so, output the minimum flux value. If not, update the initial number of cycles. After the next sampling period arrives, return to the step of obtaining and storing the current stator flux value and continue to execute until the minimum flux value is output.

[0108] In this application, the stator flux consists of two parts, one is the flux generated by the stator inductance when the motor is running, denoted as the inductance flux, and the other is the flux generated by the permanent magnet on the motor rotor, denoted as the rotor flux. Figure 6 It is a flow chart of a method for determining the motor rotor temperature. In one embodiment, the target flux value of the motor rotor flux is obtained based on the second flux value, including: determining the coordinate flux value of the second flux value under the target coordinate axis in the target coordinate system; obtaining the inductance flux value of the motor under the target coordinate axis; and determining the target flux value based on the coordinate flux value and the inductance flux value.

[0109] Obtain a position angle θ corresponding to the motor rotor in the current state of the PMSM; based on the position angle, determine the flux component of the second stator flux on the d-axis;

[0110] Specifically, according to the second magnetic flux value, the coordinate magnetic flux values ​​in the d coordinate system and the q coordinate system are determined by coordinate transformation, and the specific form is as follows: ; ;

[0111] in, is the second flux linkage value in the two-phase stationary coordinate system The magnetic flux value under the coordinate axis, is the second flux linkage value in the two-phase stationary coordinate system The magnetic flux value under the coordinate axis, is the coordinate magnetic flux value of the second magnetic flux value under the d coordinate axis in the target coordinate system, is the coordinate flux value of the second flux value under the q coordinate axis in the target coordinate system, and θ is the rotor position angle.

[0112] Obtain the inductance and current on the d-axis of the current state of the PMSM, determine the product of the two, and use it as the current inductance flux. Finally, determine the difference between the flux component of the second stator flux on the d-axis (i.e., the coordinate flux value) and the current inductance flux value. Use the difference as the current rotor flux (i.e., the target flux value of the motor rotor flux). The calculation formula is: ;

[0113] In one embodiment, the process of constructing the corresponding relationship includes:

[0114] For each of the multiple sampled temperature values, obtain the no-load back electromotive force sampled respectively under the current sampled temperature value condition and under multiple speed conditions of the motor; based on each speed condition and the no-load back electromotive force corresponding to each speed condition, obtain the corresponding flux value of the motor rotor flux, calculate the average value of the flux values ​​of the motor rotor flux corresponding to the multiple speed conditions, and obtain the flux value of the motor rotor flux under the current sampled temperature value condition; based on the multiple sampled temperature value conditions and the flux values ​​of the motor rotor flux corresponding to the sampled temperature value conditions, a corresponding relationship is established.

[0115] The correspondence between the magnetic flux value of the motor rotor magnetic flux preset in this application and the motor rotor temperature can be obtained through bench testing. The PMSM to be tested is placed in a constant temperature box, and the minimum and maximum temperatures of the test conditions are set according to the temperature range of the motor. The temperature range is determined based on the minimum and maximum temperatures, and then the temperature range is divided according to a certain temperature interval. A test point is taken at equal temperature intervals, and N sampling temperature values ​​are set;

[0116] For each sampled temperature value, under the current sampled temperature value condition, the corresponding no-load back electromotive force is measured under K preset speed conditions, so that K no-load back electromotive forces can be measured, and K magnetic flux values ​​of the motor rotor magnetic flux corresponding to the K preset speed conditions are obtained from the K preset speed conditions and the K no-load back electromotive forces, and the K magnetic flux values ​​of the motor rotor magnetic flux are averaged to obtain the magnetic flux value of the motor rotor magnetic flux corresponding to the current sampled temperature value condition;

[0117] In this way, for N sampling temperature value conditions, the corresponding N motor rotor flux values ​​can be obtained, thereby constructing a corresponding relationship between the target flux value and the preset motor rotor flux value and the motor rotor temperature.

[0118] Down Figure 7This is an example of the correspondence between the flux value of the motor rotor flux and the motor rotor temperature. The horizontal axis is the motor rotor temperature, and the vertical axis is the flux value of the motor rotor flux. Through polynomial fitting, a polynomial function with the flux value of the motor rotor flux as input and the motor rotor temperature as output is obtained, thereby obtaining the corresponding relationship.

[0119] It can be seen that the present application establishes a correspondence between the flux value of the motor rotor flux and the motor rotor temperature through an experimental method, so that after obtaining the target flux value, the target rotor temperature can be quickly determined based on the target flux value and the correspondence.

[0120] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0121] Based on the same inventive concept, the embodiment of the present application also provides a motor rotor temperature determination device for implementing the motor rotor temperature determination method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more motor rotor temperature determination device embodiments provided below can refer to the limitations of the motor rotor temperature determination method above, and will not be repeated here.

[0122] In an exemplary embodiment, Figure 8 As shown, a device 800 for determining the temperature of a motor rotor is provided, comprising:

[0123] An acquisition module 801 is used to acquire a first back electromotive force of the motor;

[0124] A processing module 802 is used to input the first back electromotive force into a second-order generalized integrator for processing to obtain a first flux value of the motor stator flux;

[0125] A first determination module 803 is used to determine a flux zero drift value, and obtain a second flux value of the motor stator flux based on the first flux value and the flux zero drift value;

[0126] A second determination module 804 is used to obtain a target flux value of the motor rotor flux based on the second flux value;

[0127] The third determination module 805 is used to obtain a target rotor temperature based on the target flux value and a preset correspondence relationship between the flux value of the motor rotor flux and the motor rotor temperature.

[0128] In one embodiment, the acquisition module 801 is specifically used to:

[0129] Obtaining three-phase voltage values ​​and three-phase current values ​​of the motor;

[0130] Based on the three-phase voltage values, voltage values ​​under coordinate axes in a two-phase stationary coordinate system are obtained;

[0131] Based on the three-phase current values, current values ​​under coordinate axes in the two-phase stationary coordinate system are obtained;

[0132] The first back electromotive force is obtained based on the voltage value and the current value.

[0133] In one embodiment, when determining the flux zero drift value, the first determination module 803 is specifically used to:

[0134] Determining a maximum value and a minimum value of the stator flux of the motor;

[0135] The flux zero drift value is determined based on the maximum flux value and the minimum flux value.

[0136] In one embodiment, when determining the maximum value of the stator flux of the motor, the first determination module 803 is specifically configured to:

[0137] Obtaining the current moment flux value of the motor stator flux;

[0138] Determining whether the flux value at the current moment is greater than a preset maximum flux value of the motor stator flux;

[0139] If yes, the current magnetic flux value is used as the maximum magnetic flux value to update the maximum magnetic flux value, and the number of cycles is increased to obtain the current number of cycles;

[0140] If not, increase the initial loop count to get the current loop count;

[0141] Determine whether the current number of cycles is not less than a preset number threshold;

[0142] If so, output the maximum value of the magnetic flux;

[0143] If not, the current number of cycles is taken as the initial number of cycles, and within the sampling period, the flux value of the motor stator flux at the next moment is obtained as the flux value at the current moment, and the step of returning to determine whether the flux value at the current moment is greater than the preset maximum flux value of the motor stator flux is continued until the maximum flux value is output.

[0144] In one embodiment, when determining the minimum value of the stator flux of the motor, the first determination module 803 is specifically used to:

[0145] Obtaining the current moment flux value of the motor stator flux;

[0146] Determining whether the current flux value is less than a preset minimum flux value of the motor stator flux;

[0147] If yes, the current magnetic flux value is used as the minimum magnetic flux value to update the minimum magnetic flux value, and the number of cycles is increased to obtain the current number of cycles;

[0148] If not, increase the initial loop count to get the current loop count;

[0149] Determine whether the current number of cycles is not less than a preset number threshold;

[0150] If so, output the minimum value of the magnetic flux;

[0151] If not, the current number of cycles is taken as the initial number of cycles, and within the sampling period, the flux value of the motor stator flux at the next moment is obtained as the flux value at the current moment, and the step of returning to determine whether the flux value at the current moment is less than the preset minimum flux value of the motor stator flux is continued until the minimum flux value is output.

[0152] In one embodiment, the second determining module 804 is specifically configured to:

[0153] Determine a coordinate magnetic flux value of the second magnetic flux value under a target coordinate axis in a target coordinate system;

[0154] Obtaining the inductance flux value of the motor under the target coordinate axis;

[0155] The target flux value is determined based on the coordinate flux value and the inductance flux value.

[0156] In one embodiment, the process of constructing the corresponding relationship includes:

[0157] For each sampled temperature value among the multiple sampled temperature values, obtain the no-load back electromotive force sampled respectively under the current sampled temperature value condition and under the multiple speed conditions of the motor; based on each speed condition and the no-load back electromotive force corresponding to each speed condition, obtain the corresponding flux value of the motor rotor flux, calculate the average value of the flux values ​​of the motor rotor flux corresponding to the multiple speed conditions, and obtain the flux value of the motor rotor flux under the current sampled temperature value condition;

[0158] The corresponding relationship is constructed based on a plurality of sampling temperature value conditions and the flux linkage values ​​of the motor rotor flux linkage respectively corresponding to the sampling temperature value conditions.

[0159] Each module in the above-mentioned motor rotor temperature determination device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0160] In an exemplary embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as shown in FIG. Fig. 9 As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, near field communication (NFC) or other technologies. When the computer program is executed by the processor, a method for determining the temperature of a motor rotor is implemented. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0161] Those skilled in the art will understand that Fig. 9The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0162] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0163] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0164] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0165] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0166] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0167] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0168] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for determining the temperature of a motor rotor, characterized in that: The method comprises: Obtain the first back electromotive force of the motor; Inputting the first back electromotive force into a second-order generalized integrator for processing to obtain a first flux value of the motor stator flux; Determine a flux zero drift value, and obtain a second flux value of the motor stator flux based on the first flux value and the flux zero drift value; Based on the second flux value, obtaining a target flux value of the motor rotor flux; Based on the target flux value and a corresponding relationship between a preset flux value of the motor rotor flux and the motor rotor temperature, a target rotor temperature is obtained.

2. The method according to claim 1, characterized in that The step of obtaining a first back electromotive force of the motor comprises: Obtaining three-phase voltage values ​​and three-phase current values ​​of the motor; Based on the three-phase voltage values, voltage values ​​under coordinate axes in a two-phase stationary coordinate system are obtained; Based on the three-phase current values, current values ​​under coordinate axes in the two-phase stationary coordinate system are obtained; The first back electromotive force is obtained based on the voltage value and the current value.

3. The method according to claim 1 or 2, characterized in that: The determining of the magnetic flux zero drift value comprises: Determining a maximum value and a minimum value of the stator flux of the motor; The flux zero drift value is determined based on the maximum flux value and the minimum flux value.

4. The method according to claim 3, characterized in that The step of determining the maximum value of the stator flux of the motor comprises: Obtaining the current moment flux value of the motor stator flux; Determining whether the flux value at the current moment is greater than a preset maximum flux value of the motor stator flux; If yes, the current magnetic flux value is used as the maximum magnetic flux value to update the maximum magnetic flux value, and the number of cycles is increased to obtain the current number of cycles; If not, increase the initial loop count to get the current loop count; Determine whether the current number of cycles is not less than a preset number threshold; If so, output the maximum value of the magnetic flux; If not, the current number of cycles is taken as the initial number of cycles, and within the sampling period, the flux value of the motor stator flux at the next moment is obtained as the flux value at the current moment, and the step of returning to determine whether the flux value at the current moment is greater than the preset maximum flux value of the motor stator flux is continued until the maximum flux value is output.

5. The method according to claim 3, characterized in that: The step of determining the minimum value of the stator flux of the motor comprises: Obtaining the current moment flux value of the motor stator flux; Determining whether the current flux value is less than a preset minimum flux value of the motor stator flux; If yes, the current magnetic flux value is used as the minimum magnetic flux value to update the minimum magnetic flux value, and the number of cycles is increased to obtain the current number of cycles; If not, increase the initial loop count to get the current loop count; Determine whether the current number of cycles is not less than a preset number threshold; If so, output the minimum value of the magnetic flux; If not, the current number of cycles is taken as the initial number of cycles, and within the sampling period, the flux value of the motor stator flux at the next moment is obtained as the flux value at the current moment, and the step of returning to determine whether the flux value at the current moment is less than the preset minimum flux value of the motor stator flux is continued until the minimum flux value is output.

6. The method according to any one of claims 1 to 5, characterized in that The step of obtaining a target flux value of the motor rotor flux based on the second flux value includes: Determine a coordinate magnetic flux value of the second magnetic flux value under a target coordinate axis in a target coordinate system; Obtaining the inductance flux value of the motor under the target coordinate axis; The target flux value is determined based on the coordinate flux value and the inductance flux value.

7. The method according to any one of claims 1 to 5, characterized in that The process of constructing the corresponding relationship includes: For each sampled temperature value among the multiple sampled temperature values, obtain the no-load back electromotive force sampled respectively under the current sampled temperature value condition and under the multiple speed conditions of the motor; based on each speed condition and the no-load back electromotive force corresponding to each speed condition, obtain the corresponding flux value of the motor rotor flux, calculate the average value of the flux values ​​of the motor rotor flux corresponding to the multiple speed conditions, and obtain the flux value of the motor rotor flux under the current sampled temperature value condition; The corresponding relationship is constructed based on a plurality of sampling temperature value conditions and the flux linkage values ​​of the motor rotor flux linkage respectively corresponding to the sampling temperature value conditions.

8. A device for determining the temperature of a motor rotor, characterized in that: The device comprises: An acquisition module, used for acquiring a first back electromotive force of the motor; A processing module, used for inputting the first back electromotive force into a second-order generalized integrator for processing to obtain a first flux value of the motor stator flux; A first determination module, configured to determine a flux zero drift value, and obtain a second flux value of a stator flux of a motor based on the first flux value and the flux zero drift value; A second determination module is used to obtain a target flux value of the motor rotor flux based on the second flux value; The third determination module is used to obtain the target rotor temperature based on the target flux value and the corresponding relationship between the preset flux value of the motor rotor flux and the motor rotor temperature.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

11. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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