A method and system for estimating the temperature rise of the rotor permanent magnet of a six-phase motor

Abstract

The present invention discloses a method and system for estimating the temperature rise of the rotor permanent magnet of a six-phase motor. The present invention includes injecting currents with equal amplitudes and opposite polarities in the harmonic planes in the mathematical model of the six-phase motor, and through the transformation of the fundamental wave plane and the harmonic wave plane, obtaining the motor equation that eliminates the motor resistance R ; calculating the permanent magnet flux linkage at the initial temperature T 0 and at any t moment of the temperature T ( t ); determining the relationship between the permanent magnet flux linkage and the temperature rise, substituting the permanent magnet flux linkage under different working conditions obtained, and obtaining the temperature rise of the rotor permanent magnet. The present invention can accurately estimate the temperature of the rotor permanent magnet for a six-phase motor. The method is more direct, and the estimated result is more accurate. It can avoid extreme situations such as high-temperature demagnetization. Moreover, the method of the present invention is simple to implement and has a low implementation cost, avoiding misjudgment caused by inaccurate indirect observation or temperature sensor measurement data, and the entire monitoring process is easy to achieve.

Description

Technical Field

[0001] The present invention relates to the technology for monitoring the temperature rise of permanent magnets in a motor rotor, and more particularly to a method and system for estimating the temperature rise of permanent magnets in the rotor of a six-phase motor. Background Art

[0002] In recent years, with the increasing emphasis on the reliability of key power components, six-phase motors have been used more and more widely. Six-phase permanent magnet motors have high power density, high performance, high efficiency, and good fault tolerance, and can meet the reliability and fault tolerance requirements of the motor system under special working conditions, and have attracted more and more attention.

[0003] Since the six-phase permanent magnet motor operates in a harsh environment, its stator windings will generate heat during operation. Under the action of thermal stress, the permanent magnets in its rotor may undergo irreversible demagnetization, seriously affecting the reliability of the motor operation. Therefore, in order to prevent the extreme situation of overheating of the permanent magnet rotor of the motor, it is necessary to estimate the operating temperature of the permanent magnets in the motor rotor.

[0004] At present, most of the existing methods for estimating the temperature of permanent magnets in the rotor of permanent magnet motors are for three-phase motors. The main methods are to indirectly observe the temperature of the stator windings or to obtain the temperature of the permanent magnets in the rotor by using the injection current method. The method of observing the resistance value of the stator windings is an indirect method and cannot directly observe the permanent magnets in the rotor, and there may be certain errors and cannot reflect the actual temperature of the permanent magnets in the rotor. By injecting fundamental current into the windings of the motor and extracting specific current and voltage signals therefrom, since harmonics are injected into its fundamental circuit, during the operation of the motor, it will cause the working condition of torque fluctuation, affecting the normal operation of the motor.

[0005] In summary, when the existing methods for estimating the temperature of permanent magnets in motors are used for six-phase motors, there are technical problems such as inaccurate temperature estimation, interference, and poor applicability. Summary of the Invention

[0006] The technical problem to be solved by the present invention: In view of the above problems of the prior art, a method and system for estimating the temperature rise of permanent magnets in the rotor of a six-phase motor are provided. The present invention can accurately estimate the temperature of the permanent magnets in the rotor for a six-phase motor. The method is more direct, and the estimated result is more accurate, which can avoid the extreme situation of high-temperature demagnetization. Moreover, the method of the present invention is simple to implement and has low implementation cost, avoiding misjudgment caused by inaccurate indirect observation or temperature sensor measurement data, and the entire monitoring process is easy to implement.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for estimating the temperature rise of the permanent magnet rotor of a six-phase motor, comprising:

[0009] 1) Inject currents with equal amplitudes and opposite polarities into the harmonic planes in the mathematical model of the six-phase motor, and through the transformation of the fundamental wave plane and the harmonic wave plane, eliminate the influence of the change in the motor resistance R on the temperature rise estimation, and obtain the motor equation after eliminating the motor resistance R ;

[0010] 2) According to the motor equation after eliminating the motor resistance R , calculate the permanent magnet flux linkage at the initial temperature T 0 and at any t time T ( t ) of the permanent magnet;

[0011] 3) Determine the relationship between the permanent magnet flux linkage and the temperature rise, and substitute the obtained permanent magnet flux linkage at the initial temperature T 0 and at any t time T ( t ) into the relationship between the permanent magnet flux linkage and the temperature rise to obtain the temperature rise of the permanent magnet rotor.

[0012] Optionally, the functional expression of the mathematical model of the six-phase motor in step 1) is:

[0013] , (1)

[0014] In the above formula, V d1 , V q1 is the fundamental wave plane dq voltage, V d2 , V q2 is the harmonic wave plane dq voltage, I d1 , I q1 is the fundamental wave plane dq current, I d2 , I q2 is the harmonic wave plane dq current, L d1 , L q1 is the fundamental wave plane dq inductance, L d2 , L q2 is the harmonic wave plane dq inductance, D d1 ,D q1 is the rotor position function of the fundamental wave plane dq axis, D d2 , D q2 is the rotor position function of the harmonic plane, R is the motor resistance, w is the motor operating frequency, V dead is the semiconductor voltage drop, λ is the magnetic flux linkage of the six-phase motor.

[0015] Optionally, injecting currents with equal amplitudes and opposite polarities in the harmonic plane in the mathematical model of the six-phase motor in step 1) means injecting currents with the same amplitude and opposite polarities into the harmonic plane I , such that I d2 =- I , I q2 = I .

[0016] Optionally, by transforming through the fundamental wave plane and the harmonic plane in step 1), the influence of the change of the motor resistance R on the temperature rise estimation is eliminated, and the motor equation after eliminating the motor resistance R includes: transforming the mathematical model of the six-phase motor to obtain the decoupled mathematical models of the fundamental wave plane and the harmonic plane; substituting the function expression of the motor resistance R in the mathematical model of the harmonic plane into the decoupled mathematical model of the fundamental wave plane, so as to obtain the motor equation after eliminating the motor resistance R .

[0017] Optionally, the decoupled mathematical models of the fundamental wave plane and the harmonic plane obtained are as shown in the following formula:

[0018] V d1 I d1 + V q1 I q1 = RI s 2 + wI q1 ( L Δ I d1 + λ 0)+( I d1 D d1+ I q1 D q1 ) V dead ,(2)

[0019] V q2 - V d2 = R ( I q2 - I d2 )+ w ( L d2 I d2 + L q2 I q2 )+( D q2 - D d2 ) V dead ,(3)

[0020] In the above formula, I s 2 = I d1 2 + I q1 2 , L Δ is the difference between the dq inductances of the fundamental wave plane, and there is L Δ = I d1 - I q1 。

[0021] Optionally, in the mathematical model of the harmonic plane, the motor resistance R has the following functional expression:

[0022] R= ( V q2 - V q2 - w ( L d2 I d2 + L q2 I q2 )- ( D q2 - D d2 ) V dead ) / ( I q2 - I d2 ) ,(4)

[0023] The functional expression of the motor equation eliminating the motor resistance R obtained is as shown in the following formula:

[0024] α 1 = wI q1 ( L Δ I d1 + λ 0)+ κ 1 V dead ,(5)

[0025] In the above formula, α 1 is a physical quantity containing voltage information, κ 1 is a physical quantity containing current information, and there is:

[0026] α 1 = V d1 I d1 + V q1 I q1 - γI s 2 ( V q2 - V d2 ) ,(6)

[0027] κ 1 = I d1 D d1 + I q1 D q1 - γI s 2 ( D q2 - D d2 ),(7)

[0028] Among them, the intermediate variableγ = 1 / (2 I ), where I represents the current injected into the harmonic plane.

[0029] Optionally, the permanent magnet flux linkage calculated in step 2) at the initial temperature T 0 and at any t time T ( t ) are respectively:

[0030] λ 0 = ( α 1,0 - κ 1,0 V dead ) / w 0 I q1,t - L Δ,t I d1,t , (8)

[0031] λ T ( t ) = ( α 1,t - κ 1,t V dead ) / w t I q1,t - L Δ,t I d1,t , (9)

[0032] In the above formula, λ 0 is the magnitude of the permanent magnet flux linkage at the initial temperature T 0 , α 1,0 is a physical quantity containing voltage information at the initial temperature T 0 , α 1, κ 1,0 is a physical quantity containing current information at the initial temperature T 0 , κ 1, V dead is the semiconductor voltage drop, w 0 is the initial temperature T 0The motor operating frequency under I d1,t and I q1,t are respectively the T 0 axial current in the fundamental wave plane under the initial temperature dq ; L Δ,t is the difference between the dq inductances in the fundamental wave plane under the initial temperature T 0 ; λ T ( t ) is the magnitude of the permanent magnet flux linkage at any t moment at the temperature T ( t ); α 1,t is a physical quantity containing voltage information at the current temperature T ( t ); α 1, κ 1,t is a physical quantity containing current information at the current temperature T ( t ); κ 1, w t is the motor operating frequency at the current temperature T ( t ).

[0033] Optionally, step 3) includes:

[0034] 3.1) Determine the relationship between the permanent magnet flux linkage and the temperature rise as shown in the following formula:

[0035] λ T ( t ) = λ 0 - (1 + β ( T ( t ) - T 0 ), (10)

[0036] In the above formula, λ T ( t ) is the magnitude of the permanent magnet flux linkage at any t moment at the temperature T ( t ); λ 0 is the magnitude of the permanent magnet flux linkage at the initial temperature T 0 ; β is the permanent magnet temperature coefficient; T (t ) - T 0 represents t the temperature at a moment T ( t ) the temperature rise relative to the initial temperature T 0 ;

[0037] 3.2) Substitute the obtained temperature at the initial temperature T 0 and any t moment's temperature T ( t ) into the relationship between the permanent - magnet flux linkage and the temperature rise, and the calculation function expression of the temperature rise of the rotor permanent magnet is obtained as shown in the following formula:

[0038] ∆T = T ( t ) - T 0 = (( α 1,t - κ 1,t V dead ) / w t I q1,t - ( α 1,0 - κ 1,0 V dead ) / w 0 I q1,t ) / βλ 0, (11)

[0039] In the above formula, ∆T represents the temperature rise of the rotor permanent magnet.

[0040] In addition, the present invention also provides a system for estimating the temperature rise of the rotor permanent magnet of a six - phase motor, including a microprocessor and a memory connected to each other, and the microprocessor is programmed or configured to execute the steps of the method for estimating the temperature rise of the rotor permanent magnet of the six - phase motor.

[0041] In addition, the present invention also provides a computer - readable storage medium, in which a computer program is stored, and the computer program is used to be executed by a computer device to implement the steps of the method for estimating the temperature rise of the rotor permanent magnet of the six - phase motor.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] 1. The present invention achieves full decoupling through a six-phase motor, transforms the motor mathematical model, and eliminates the problem of inaccurate estimation caused by changes in the motor resistance. By injecting currents with equal magnitudes and opposite directions into its harmonic plane, the estimation of the rotor temperature of the six-phase motor is realized. Since no torque is generated in the harmonic plane, there will be no problem of torque fluctuation. Compared with the traditional methods of indirectly observing the stator resistance and injecting currents in the fundamental wave plane, this method is more direct and the estimated results are more accurate. The present invention can estimate the temperature rise of the permanent magnet on the rotor of the six-phase motor online, thus avoiding extreme situations such as high-temperature demagnetization.

[0044] 2. The method of the present invention only needs to collect the six-phase current signals and voltage signals in the converter, without installing temperature sensors on the internal permanent magnet of the rotor, reducing the cost of the online monitoring technology, avoiding misjudgment caused by inaccurate indirect observation or temperature sensor measurement data, and the entire monitoring process is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic structural diagram of the method of the embodiment of the present invention.

[0046] Figure 2 It is a schematic structural diagram of the device of the embodiment of the present invention.

[0047] Figure 3 It is a schematic structural diagram of the system of the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] To make the above objects, technical solutions and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. 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.

[0049] As Figure 1 shown, the method for estimating the temperature rise of the permanent magnet on the rotor of the six-phase motor in this embodiment includes:

[0050] 1) Inject currents with equal magnitudes and opposite polarities into the harmonic plane in the mathematical model of the six-phase motor, and through the transformation between the fundamental wave plane and the harmonic plane, eliminate the influence of the change in the motor resistance R on the temperature rise estimation, and obtain the motor equation after eliminating the motor resistance R ;

[0051] 2) According to the motor equation after eliminating the motor resistance R , calculate to obtain at the initial temperature T0 and any t temperature at a moment T ( t ) the permanent magnet flux linkage;

[0052] 3) Determine the relationship between the permanent magnet flux linkage and the temperature rise, and substitute the obtained initial temperature into the relationship between the permanent magnet flux linkage and the temperature rise T 0 and any t temperature at a moment T ( t ) the permanent magnet flux linkage to obtain the temperature rise of the rotor permanent magnet.

[0053] In this embodiment, currents with equal amplitudes and opposite polarities are injected into the harmonic planes in the mathematical model of the six-phase motor, and through the transformation between the fundamental wave plane and the harmonic wave plane, the influence of the change of the motor resistance R on the temperature rise estimation is eliminated, and the motor equation eliminating the motor resistance R is obtained, which can eliminate the interference of the motor resistance R on the temperature rise calculation of the rotor permanent magnet. This embodiment includes using the relationship between the permanent magnet flux linkage and the temperature rise, and substituting the obtained initial temperature T 0 and any t temperature at a moment T ( t ) the permanent magnet flux linkage to obtain the temperature rise of the rotor permanent magnet. For the six-phase motor, the accurate estimation of the rotor permanent magnet temperature can be realized, the method is more direct, and the obtained estimation result is more accurate, which can avoid the extreme situation of high-temperature demagnetization. The method of this embodiment is simple to implement, has a low implementation cost, avoids misjudgment caused by inaccurate indirect observation or temperature sensor measurement data, and the whole monitoring process is easy to realize.

[0054] In this embodiment, the function expression of the mathematical model of the six-phase motor in step 1) is:

[0055] , (1)

[0056] In the above formula, V d1 , V q1 is the fundamental wave plane dq voltage, V d2 , V q2 is the harmonic wave plane dq voltage, I d1 , I q1 is the fundamental wave plane dq current, I d2 ,I q2 is the harmonic plane dq current, L d1 , L q1 is the fundamental plane dq inductance, L d2 , L q2 is the harmonic plane dq inductance, D d1 , D q1 is the fundamental plane dq axis rotor position function, D d2 , D q2 is the harmonic plane rotor position function, R is the motor resistance, w is the motor operating frequency, V dead is the semiconductor voltage drop, λ is the magnetic flux of the six-phase motor.

[0057] In this embodiment, injecting currents with equal amplitudes and opposite polarities into the harmonic plane in step 1) in the mathematical model of the six-phase motor means injecting currents with the same amplitude and opposite polarities into the harmonic plane I , such that I d2 = - I , I q2 = I . The existing permanent magnet temperature estimation method is to inject different operating dq-axis currents during the operation of the motor, and calculate the magnetic flux of the permanent magnet motor through the voltage equation of the motor. However, injecting different dq currents will affect the normal operation of the motor. In this embodiment, injecting currents with the same amplitude and opposite polarities into the harmonic plane I will not affect the normal operation of the motor.

[0058] In this embodiment, in step 1), by transforming the fundamental plane and the harmonic plane, the influence of the change of the motor resistance R on the temperature rise estimation is eliminated, and the motor equation eliminating the motor resistance R is obtained, including: transforming the mathematical model of the six-phase motor to obtain the decoupled mathematical model of the fundamental plane and the mathematical model of the harmonic plane; substituting the function expression of the motor resistance R in the mathematical model of the harmonic plane into the decoupled mathematical model of the fundamental plane, so as to obtain the motor equation eliminating the motor resistance R .

[0059] In this embodiment, the mathematical models of the decoupled fundamental wave plane and the harmonic wave plane are shown as follows:

[0060] V d1 I d1 + V q1 I q1 = RI s 2 + wI q1 ( L Δ I d1 + λ 0)+( I d1 D d1 + I q1 D q1 ) V dead ,(2)

[0061] V q2 - V d2 = R ( I q2 - I d2 )+ w ( L d2 I d2 + L q2 I q2 )+( D q2 - D d2 ) V dead ,(3)

[0062] In the above formula, I s 2 = I d1 2 + I q1 2 , L Δ is the difference between the dq inductances of the fundamental wave plane, and there is LΔ = I d1 - I q1 。

[0063] In this embodiment, the functional expression of the motor resistance in the mathematical model of the harmonic plane is as follows: R

[0064] R= ( V q2 - V q2 - w ( L d2 I d2 + L q2 I q2 ) - ( D q2 - D d2 ) V dead ) / ( I q2 - I d2 ) , (4)

[0065] Substitute the functional expression of the motor resistance in the mathematical model of the harmonic plane in formula (3) into formula (2): R

[0066] V d1 I d1 + V q1 I q1 =( V q2 - V q2 - w ( L d2 I d2 + L q2 I q2 ) - ( D q2 - D d2 ) V dead ) / ( I ​​q2 - I d2 ) I s 2

[0067] + wI q1 ( L Δ I d1 + λ 0)+( I d1 D d1 + I q1 D q1 ) V dead

[0068] By injecting currents with the same amplitude and opposite polarities into its harmonic planes I , there is I d2 =- I , I q2 = I . It can be obtained that V q2 - V d2 =2 RI+ ( D q2 - D d2 ) V dead , substituting it into Equation (2), the functional expression of the motor equation eliminating the motor resistance R is shown as follows

[0069] α 1= wI q1 ( L Δ I d1 + λ 0)+ κ 1 V dead , (5)

[0070] In the above formula α 1 is a physical quantity containing voltage information κ 1 is a physical quantity containing current information, and there is

[0071] α 1= V d1I d1 + V q1 I q1 - γI s 2 ( V q2 - V d2 ) , (6)

[0072] κ 1= I d1 D d1 + I q1 D q1 - γI s 2 ( D q2 - D d2 ) , (7)

[0073] where the intermediate variable γ =1 / (2 I ), where I represents the current injected into the harmonic plane.

[0074] In step 2) of this embodiment, the permanent magnet flux linkage calculated at the initial temperature T 0 and at any t time T ( t ) are respectively:[[]]

[0075] λ 0=( α 1,0 - κ 1,0 V dead ) / w 0 I q1,t - L Δ,t I d1,t , (8)

[0076] λ T ( t )=( α 1,t - κ 1,tV dead ) / w t I q1,t - L Δ,t I d1,t ,(9)

[0077] In the above formula, λ 0 is the magnitude of the permanent magnet flux linkage at the initial temperature T 0 under which, α 1,0 is the physical quantity containing voltage information at the initial temperature T 0 under which, α 1 (calculated using Equation (6)), κ 1,0 is the physical quantity containing current information at the initial temperature T 0 under which, κ 1 (calculated using Equation (7)), V dead is the semiconductor voltage drop, w 0 is the motor operating frequency at the initial temperature T 0 under which, I d1,t and I q1,t are respectively the T 0 axis current in the fundamental wave plane at the initial temperature dq under which, L Δ,t is the difference between the dq inductances in the fundamental wave plane at the initial temperature T 0 ; λ T ( t ) is the magnitude of the permanent magnet flux linkage at any t time at the temperature T ( t ) under which, α 1,t is the current temperature T ( t ) under which, α 1 (calculated using Equation (6)), κ 1,t is the physical quantity containing current information at the current temperature T ( t ) under which, κ 1 (calculated using Equation (7)), w tis the current temperature T ( t ) is the motor operating frequency at

[0078] In this embodiment, step 3) includes:

[0079] 3.1) Determine the relationship between the permanent magnet flux linkage and the temperature rise as shown in the following formula:

[0080] λ T ( t ) = λ 0 - (1 + β ( T ( t ) - T 0 )),(10)

[0081] In the above formula, λ T ( t ) is the magnitude of the permanent magnet flux linkage at any t time at temperature T ( t ), λ 0 is the magnitude of the permanent magnet flux linkage at the initial temperature T 0 , β is the permanent magnet temperature coefficient, T ( t ) - T 0 represents the temperature rise of the temperature T ( t ) at time t relative to the initial temperature T 0 ; Currently, the rotor of a permanent magnet motor usually uses a permanent magnet material with a high energy product material, and its permanent magnet remanence ability determines the performance of the permanent magnet motor, which is closely related to temperature. The magnitude of the magnetic flux of a permanent magnet motor is related to temperature and maintains a linear relationship as shown in Equation (10). Therefore, by estimating the magnitude of the permanent magnet flux linkage, the temperature of the rotor permanent magnet can be estimated.

[0082] 3.2) Substitute the permanent magnet flux linkages at the initial temperature T 0 and the temperature t at any T ( t ) obtained in the relationship between the permanent magnet flux linkage and the temperature rise into the formula, and the calculation function expression of the temperature rise of the rotor permanent magnet is as shown in the following formula:

[0083] ∆T = T ( t ) - T 0=(( α 1,t - κ 1,t V dead ) / w t I q1,t -( α 1,0 - κ 1,0 V dead ) / w 0 I q1,t ) / βλ 0, (11)

[0084] In the above formula, ∆T represents the temperature rise of the rotor permanent magnet.

[0085] In summary, the method of this embodiment includes decoupling a six-phase motor to establish a fundamental wave and harmonic plane mathematical model equation; eliminating the influence of resistance on the accuracy of temperature rise estimation by transforming the mathematical model of the motor. And by injecting current into its harmonic plane, the magnetic flux value of the permanent magnet is extracted, and then by injecting the same magnitude of current, the initial magnetic flux of the motor rotor is obtained, and the temperature of the permanent magnet can be obtained by derivation. By injecting current into the harmonic plane, this current will not affect the torque ripple of the motor, so as to estimate the temperature rise of the online motor and improve the reliability of the motor system.

[0086] As Figure 2 shown, this embodiment also provides a device corresponding to the foregoing method, which respectively includes: a harmonic plane current injection unit for giving the dq-axis current of the harmonic plane to obtain the voltage equation of the injected harmonic plane. A current and rotor position sampling unit for obtaining the current components of the fundamental wave plane and the harmonic plane in the rotating coordinate system by performing coordinate components on the collected six-phase current and rotor position information. A motor vector control unit for obtaining the reference voltage when the motor operates stably through PI vector control V d 、 V q and V d1 、 V q1 . A rotor magnetic flux calculation unit for calculating the rotor permanent magnet magnetic flux λ T ( t ) and the rotor permanent magnet magnetic flux at normal temperature λ0. The rotor permanent magnet temperature rise calculation unit is used to calculate the rotor permanent magnet temperature rise based on the rotor flux linkage result obtained from the previous calculation. ∆T .

[0087] Figure 3 FIG. is a schematic structural diagram of the six-phase motor rotor permanent magnet temperature estimation system according to an embodiment of the present invention. As Figure 3 shown, the system mainly includes a DC power supply, a six-phase inverter, a controller, and a six-phase motor, etc. The system adopts a six-phase fully decoupled vector control method based on magnetic field orientation, uses the current and actual speed of the motor as the input parameters of the control system, and controls the six-phase motor by outputting PWM modulation signals. In order to improve the accuracy of the rotor permanent magnet temperature, the influence brought by the dead zone effect of the converter nonlinear factor is considered in the control link. As Figure 3 shown, the detected six-phase current (only four phases need to be detected in practice, as shown in the figure i a , i b and i d , i e ) is transformed from the 6 / 4 rotating coordinate system to the stationary coordinate system, and then the current generated by the 6 / 4 transformation is high-pass filtered to obtain i α , i β and i α1 , i β1 , and then transformed to the rotating coordinate system (4s / 4r) to obtain the DC components in the dq-axis coordinate system. The decoupled current is managed by PI regulators through the fundamental plane current and the harmonic plane current respectively to obtain the reference voltages V d1 , V q1 and V d2 , V q2 . Different from the traditional current injection method, in the method of this embodiment, current is injected into its harmonic plane, as Figure 3 shown, the I d2 , I q2 currents have equal amplitudes and opposite directions. Finally, the obtained reference voltages are used to generate modulation signals to control the six-phase inverter to supply power to the six-phase motor.

[0088] In addition, this embodiment also provides a system for estimating the temperature rise of the permanent magnet rotor of a six-phase motor, including a microprocessor and a memory connected to each other. The microprocessor is programmed or configured to execute the steps of the method for estimating the temperature rise of the permanent magnet rotor of the aforementioned six-phase motor.

[0089] In addition, this embodiment also provides a computer-readable storage medium storing a computer program, and the computer program is used to be executed by a computer device to implement the steps of the method for estimating the temperature rise of the permanent magnet rotor of the aforementioned six-phase motor.

[0090] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes. The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowcharts and / or block diagrams, and the combination of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in one process Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks specified in the flowchart and / or block diagram. These computer program instructions can also be stored in a computer-readable memory capable of guiding a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured product including an instruction device, and the instruction device implements the functions specified in one process Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks specified in the flowchart and / or block diagram. These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Therefore, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one process Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks specified in the flowchart and / or block diagram.

[0091] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A method for estimating the temperature rise of the rotor permanent magnet of a six-phase motor, characterized in that, including: 1) Inject currents with equal amplitudes and opposite polarities in the harmonic planes of the mathematical model of the six-phase motor, and through the transformation of the fundamental wave plane and the harmonic wave plane, eliminate the influence of the change in the motor resistance on the temperature rise estimation, and obtain the motor equation with the motor resistance eliminated. R The influence of the change in the motor resistance on the temperature rise estimation is eliminated, and the motor resistance R is eliminated to obtain the motor equation. 2) According to the motor equation for eliminating the motor resistance R , the permanent magnet flux linkage at the initial temperature T 0 and at any t time T ( t ) is calculated; 3) Determine the relationship between the permanent magnet flux linkage and the temperature rise, and substitute the obtained permanent magnet flux linkage at the initial temperature T 0 and any t time temperature T ( t ) into the relationship between the permanent magnet flux linkage and the temperature rise to obtain the temperature rise of the rotor permanent magnet; In step 1), through the transformation of the fundamental wave plane and the harmonic wave plane, the influence of the change in the motor resistance R on the temperature rise estimation is eliminated, and the motor equation with the motor resistance R eliminated is obtained, including: transforming the mathematical model of the six-phase motor to obtain the decoupled mathematical models of the fundamental wave plane and the harmonic wave plane; substituting the function expression of the motor resistance R in the mathematical model of the harmonic wave plane into the decoupled mathematical model of the fundamental wave plane, so as to obtain the motor equation with the motor resistance R eliminated; The mathematical models of the decoupled fundamental wave plane and the harmonic wave plane are shown as follows: V d1 I d1 + V q1 I q1 = RI s 2 + wI q1 ( L Δ I d1 + λ 0)+( I d1 D d1 + I q1 D q1 ) V dead ，（2） V q2 - V d2 = R ( I q2 - I d2 )+ w ( L d2 I d2 + L q2 I q2 )+( D q2 - D d2 ) V dead ，（3） In the above formula, V d1 , V q1 is the fundamental plane dq voltage, V d2 , V q2 is the harmonic plane dq voltage, I d1 , I q1 is the fundamental plane dq current, I d2 , I q2 is the harmonic plane dq current, D d1 , D q1 is the fundamental plane dq-axis rotor position function, D d2 , D q2 is the harmonic plane rotor position function, w is the motor operating frequency, V dead is the semiconductor voltage drop, λ 0 is T the magnitude of the permanent magnet flux linkage at the initial temperature I s 2 = I d1 2 + I q1 2 , L Δ is the fundamental plane dq inductance difference, and there is L Δ = I d1 - I q1 ; The motor resistance in the mathematical model of the harmonic plane R has the following functional expression: R= ( V q2 - V q2 - w ( L d2 I d2 + L q2 I q2 ) - ( D q2 - D d2 ) V dead ) / ( I q2 - I d2 ) ，（4） The obtained motor equation eliminating the motor resistance The functional expression of the motor equation is shown as follows: α 1= wI q1 ( L Δ I d1 + λ 0)+ κ 1 V dead ，（5） In the above formula, α 1 is a physical quantity containing voltage information, κ 1 is a physical quantity containing current information, and there is: α 1= V d1 I d1 + V q1 I q1 - γI s 2 ( V q2 - V d2 ) ，（6） κ 1= I d1 D d1 + I q1 D q1 - γI s 2 ( D q2 - D d2 )，（7） Among them, the intermediate variable γ = 1 / (2 I ), where I represents the current injected into the harmonic plane; The permanent magnet flux linkage calculated in step 2) at the initial temperature T 0 and at any t time is T ( t ) respectively as follows: λ 0=( α 1,0 - κ 1,0 V dead ) / w 0 I q1,t - L Δ,t I d1,t ，（8） λ T ( t )=( α 1,t - κ 1,t V dead ) / w t I q1,t - L Δ,t I d1,t ，（9） In the above formula, α 1,0 is the initial temperature T a physical quantity containing voltage information at 0 α 1, κ 1,0 is the initial temperature T a physical quantity containing current information at 0 κ 1, w 0 is the initial temperature T the motor operating frequency at 0, I d1,t and I q1,t are respectively the initial temperature T at 0 of the dq axial current in the fundamental wave plane, L Δ,t is the initial temperature T the dq inductance difference in the fundamental wave plane at 0; λ T ( t ) is the temperature t at any T ( t ) of the magnitude of the permanent magnet flux linkage, α 1,t is the current temperature T ( t ) a physical quantity containing voltage information at α 1, κ 1,t is the current temperature T ( t ) a physical quantity containing current information at κ 1, w t is the current temperature T ( t ) the motor operating frequency at; Step 3) includes: 3.1) Determine the relationship between the permanent magnet flux linkage and the temperature rise as shown in the following formula: λ T ( t )= λ 0-(1+ β ( T ( t )- T 0))，（10） In the above formula, β is the temperature coefficient of the permanent magnet, T ( t ) - T 0 represents the temperature at time t T ( t ) is the temperature rise relative to the initial temperature T 0. 3.2) Substitute the obtained initial temperature T 0 and any t moment temperature T ( t ) into the relationship between the permanent magnet flux linkage and the temperature rise, and the calculation function expression of the temperature rise of the rotor permanent magnet is shown as follows: ∆T = T ( t )- T 0=(( α 1,t - κ 1,t V dead ) / w t I q1,t -( α 1,0 - κ 1,0 V dead ) / w 0 I q1,t ) / βλ 0，（11） In the above formula, ∆T represents the temperature rise of the rotor permanent magnet.

2. The method for estimating the temperature rise of the rotor permanent magnet of the six-phase motor according to claim 1, characterized in that, The functional expression of the mathematical model of the six-phase motor in Step 1) is: ，（1） In the above formula, V d1 , V q1 is the fundamental plane dq voltage, V d2 , V q2 is the harmonic plane dq voltage, I d1 , I q1 is the fundamental plane dq current, I d2 , I q2 is the harmonic plane dq current, L d1 , L q1 is the fundamental plane dq inductance, L d2 , L q2 is the harmonic plane dq inductance, D d1 , D q1 is the fundamental plane dq-axis rotor position function, D d2 , D q2 is the harmonic plane rotor position function, R is the motor resistance, w is the motor operating frequency, V dead is the semiconductor voltage drop, λ is the magnetic flux of the six-phase motor.

3. The method for estimating the temperature rise of the permanent magnet of the rotor of a six-phase motor according to claim 2, wherein In step 1), injecting currents with equal amplitudes and opposite polarities into the harmonic planes in the mathematical model of the six-phase motor means injecting currents with the same amplitude and opposite polarities into the harmonic planes I , such that I d2 = - I , I q2 = I .

4. A rotor permanent magnet temperature rise estimation system for a six-phase motor, comprising a microprocessor and a memory connected to each other, characterized in that, The microprocessor is programmed or configured to execute the steps of the method for estimating the temperature rise of the rotor permanent magnet of the six-phase motor according to any one of claims 1 to 3.

5. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, and the computer program is used to be executed by a computer device to implement the steps of the method for estimating the temperature rise of the rotor permanent magnet of the six-phase motor according to any one of claims 1 to 3.

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