Dual three-phase permanent magnet synchronous motor rotor temperature estimation method and device and electronic equipment

Abstract

The invention provides a dual three-phase permanent magnet synchronous motor rotor temperature estimation method and device and electronic equipment, and the method comprises the steps: obtaining a stator flux linkage filtering value based on a voltage equation of a dual three-phase permanent magnet synchronous motor in a two-phase static coordinate system and a second-order generalized integrator; according to the stator flux linkage filtering value, a phase-locked loop is adopted to obtain the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor; estimating a permanent magnet flux linkage based on a voltage equation and a synchronous angular frequency of the dual three-phase permanent magnet synchronous motor under a two-phase rotating coordinate system; and calculating a rotor temperature estimation value of the dual three-phase permanent magnet synchronous motor according to the permanent magnet flux linkage. According to the method, the interference of subharmonics on rotation speed estimation is effectively reduced, the influence of system noise on the rotor temperature estimation precision is suppressed, the defect that the rotor temperature is difficult to estimate on line due to the fact that the speed and the rotor flux linkage cannot be estimated at the same time in the prior art is overcome, and high-precision estimation of the rotor temperature is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of renewable energy and energy storage, and particularly to a method, device and electronic equipment for estimating the rotor temperature of a dual three-phase permanent magnet synchronous motor. Background Art

[0002] The access of renewable energy to the power grid through various power electronic converters has increased the complexity of the power system in aspects such as stability and protection, economic operation, planning and scheduling. Under the condition of high proportion of renewable energy grid connection, the power grid frequency modulation puts forward higher requirements for the energy storage system, such as increasing the energy storage system capacity, high power and long backup time, providing inertia to a low-inertia power system, etc. As a mechanical energy storage, flywheel energy storage has the advantages of high power density and long cycle life. Since the 1990s, with the development of bearing technology and flywheel rotor material technology in flywheel energy storage, flywheel energy storage technology has developed rapidly and has gradually been promoted to the commercial range. The development of power electronic technology ensures the efficient conversion between electrical energy and mechanical energy in the flywheel energy storage system.

[0003] At present, the main obstacle to the application of the flywheel system in the power grid is that the capacity of the flywheel energy storage system is small and it is difficult to provide energy support for a long time. The solutions to improve the energy of the flywheel energy storage system mainly include forming a flywheel energy storage array and increasing the energy storage capacity of a single flywheel. Among them, the idea of increasing the energy storage capacity of a single flywheel includes two types. One is to improve the maximum speed that the flywheel can withstand by studying the materials and bearing technology that make up the flywheel rotor; the other is to introduce a multi-phase motor to reduce the capacity requirement of a single converter, and correspondingly reduce the harmonic current of the flywheel energy storage and improve the quality of the electrical energy output.

[0004] In a flywheel energy storage system, a dual three-phase permanent magnet synchronous motor is a key component for the conversion between mechanical energy and electrical energy, and its reliable operation is of great significance to the stable operation of the power grid. The flywheel rotor is connected to the rotor of the dual three-phase permanent magnet synchronous motor through a mechanical mechanism and generally operates for a long time to store energy. During this process, various losses inside the motor (such as iron loss, copper loss, mechanical loss, etc.) continuously generate heat, resulting in an increase in the rotor temperature. After reaching a certain temperature, the rotor permanent magnet will be permanently demagnetized, and the flywheel energy storage system will also stop working. Therefore, real-time estimation of the rotor temperature of the dual three-phase permanent magnet synchronous motor can ensure the reliable operation of the flywheel energy storage system, which has very important theoretical and practical significance.

[0005] The existing rotor temperature estimation schemes for dual three-phase permanent magnet synchronous motors include the flux linkage model method. The flux linkage model method establishes a flux linkage observer of a continuous model based on the voltage equation in the d-q axis coordinate system, introduces the difference between the estimated current and the actual current as feedback, establishes the corresponding relationship between the rotor temperature and the flux linkage, and estimates the real-time rotor temperature according to the value of the flux linkage observer. This method has a large applicable range and does not require high processing capacity of the controller CPU.

[0006] However, on the one hand, the flux model method uses the voltage equation in the dq coordinate system to estimate the rotor flux, in which the speed is regarded as a known quantity. In the speed sensorless control system of the dual three-phase permanent magnet synchronous motor, both the speed and the rotor flux are unknown quantities. Using a single dq voltage equation cannot simultaneously estimate the speed and rotor flux, making it difficult to monitor the rotor temperature online.

[0007] On the other hand, the flux linkage model method uses the difference between the estimated and actual currents as feedback. Once the feedback gain is determined, this method has a fixed observation bandwidth. However, when a dual three-phase permanent magnet synchronous motor sensorless control system operates under complex operating conditions, the system noise is unknown and time-varying, making it difficult to achieve optimal temperature estimation accuracy.

[0008] Therefore, how to solve the problem that the existing dual three-phase permanent magnet synchronous motor rotor temperature estimation method cannot simultaneously estimate the speed and rotor flux, resulting in difficulty in online estimation of the rotor temperature, is an important issue that needs to be urgently addressed in the field of renewable energy and energy storage. Summary of the Invention

[0009] The present invention provides a method, device and electronic equipment for estimating the rotor temperature of a dual three-phase permanent magnet synchronous motor, which is used to overcome the defect of the existing dual three-phase permanent magnet synchronous motor rotor temperature estimation method that is difficult to estimate the rotor temperature online due to the inability to simultaneously estimate the speed and rotor flux, and achieve high-precision estimation of the rotor temperature.

[0010] On the one hand, the present invention provides a method for estimating the rotor temperature of a dual three-phase permanent magnet synchronous motor, which is applied to a flywheel energy storage system. The method includes: obtaining a stator flux filter value based on the voltage equation of the dual three-phase permanent magnet synchronous motor in a two-phase stationary coordinate system and a second-order generalized integrator; obtaining the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor using a phase-locked loop according to the stator flux filter value; estimating the permanent magnet flux based on the voltage equation of the dual three-phase permanent magnet synchronous motor in a two-phase rotating coordinate system and the synchronous angular frequency; and calculating an estimated rotor temperature value of the dual three-phase permanent magnet synchronous motor based on the permanent magnet flux.

[0011] Furthermore, the stator flux filtering value is obtained based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system and the second-order generalized integrator, including: estimating the stator flux estimation value through a stator flux estimation model based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system; and obtaining the stator flux filtering value based on the stator flux estimation value based on the second-order generalized integrator.

[0012] Further, estimating the permanent magnet flux linkage based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system and the synchronous angular frequency includes: constructing a reduced-order permanent magnet flux linkage observation state equation according to the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system and the synchronous angular frequency; solving the stator current in the two-phase rotating coordinate system according to the reduced-order permanent magnet flux linkage observation state equation; discretizing the Kalman filter equation with the stator current and the permanent magnet flux linkage in the two-phase rotating coordinate system as state variables to obtain the estimated permanent magnet flux linkage.

[0013] Further, the stator flux linkage estimation model is defined as follows: ; The transfer function of the second-order generalized integrator is defined as follows: ; Where, and represent the estimated values of the stator flux linkage, and represent the stator voltages of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system, represents the stator resistance of the dual three-phase permanent magnet synchronous motor, and represent the stator currents of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system, represents the transfer function of the second-order generalized integrator, represents the output of the transfer function, represents the input of the transfer function, represents the damping coefficient, represents the resonant angular frequency, represents the complex variable.

[0014] Further, the reduced-order permanent magnet flux linkage observation state equation is defined as follows: ; Where, and represent the stator currents of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, and represent the stator inductances of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the stator voltage of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the stator resistance of the dual three-phase permanent magnet synchronous motor, represents the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor, represents the permanent magnet flux linkage of the dual three-phase permanent magnet synchronous motor.

[0015] Furthermore, the discretization process of the Kalman filter equation is as follows: ; ; ; ; ; in, represents the state prediction value, represents the state transition matrix, represents the optimal state estimate at the previous moment, , represents the q-axis stator voltage of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the q-axis stator current of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the estimated synchronous angular frequency of the dual three-phase permanent magnet synchronous motor, represents the sampling time, represents the sampling time, 、 They represent the q-axis stator inductance and d-axis stator inductance of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the error covariance matrix predicted value, represents the optimal estimate of the error covariance matrix at the previous moment, represents the system noise covariance matrix, represents the Kalman filter gain matrix, represents the output matrix, represents the measurement error covariance matrix, Indicates the actual measured current.

[0016] Furthermore, the calculation formula of the estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor is as follows: ; in, represents the estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor, Indicates temperature, express The estimated value of the permanent magnet flux at time , Indicates the temperature The permanent magnet flux value at time represents the thermal constant of the permanent magnet.

[0017] Second aspect, the present invention further provides a rotor temperature estimation device for a dual-three-phase permanent magnet synchronous motor, which is applied to a flywheel energy storage system. The device includes: a stator flux filtering value acquisition module, configured to acquire a stator flux filtering value based on the voltage equation of the dual-three-phase permanent magnet synchronous motor in a two-phase stationary coordinate system and a second-order generalized integrator; a synchronous angular frequency acquisition module, configured to acquire the synchronous angular frequency of the dual-three-phase permanent magnet synchronous motor by using a phase-locked loop according to the stator flux filtering value; a permanent magnet flux estimation module, configured to estimate the permanent magnet flux based on the voltage equation of the dual-three-phase permanent magnet synchronous motor in a two-phase rotating coordinate system and the synchronous angular frequency; and a rotor temperature estimation value calculation module, configured to calculate the rotor temperature estimation value of the dual-three-phase permanent magnet synchronous motor according to the permanent magnet flux.

[0018] Third aspect, the present invention further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements the rotor temperature estimation method for a dual-three-phase permanent magnet synchronous motor as described in any one of the above.

[0019] Fourth aspect, the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the rotor temperature estimation method for a dual-three-phase permanent magnet synchronous motor as described in any one of the above.

[0020] The rotor temperature estimation method for a dual-three-phase permanent magnet synchronous motor provided by the present invention acquires a stator flux filtering value by using the voltage equation of the dual-three-phase permanent magnet synchronous motor in a two-phase stationary coordinate system and a second-order generalized integrator, and acquires the synchronous angular frequency of the dual-three-phase permanent magnet synchronous motor by using a phase-locked loop according to the stator flux filtering value. Furthermore, the permanent magnet flux is estimated based on the voltage equation of the dual-three-phase permanent magnet synchronous motor in a two-phase rotating coordinate system and the synchronous angular frequency. Thus, the rotor temperature estimation value of the dual-three-phase permanent magnet synchronous motor is calculated according to the permanent magnet flux. This method uses the voltage equation of the dual-three-phase permanent magnet synchronous motor in a two-phase stationary coordinate system combined with a second-order generalized integrator to estimate the synchronous speed (i.e., the synchronous angular frequency), uses the voltage equation of the dual-three-phase permanent magnet synchronous motor in a two-phase rotating coordinate system to estimate the permanent magnet flux, and then estimates the rotor temperature, effectively reducing the interference of the sub-harmonic wave on the speed estimation, suppressing the influence of the system noise on the rotor temperature estimation accuracy, overcoming the defect of the prior art that it is difficult to estimate the rotor temperature online because the speed and the rotor flux cannot be estimated simultaneously, and achieving a high-precision estimation of the rotor temperature. Description of the Drawings

[0021] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 FIG. is a schematic flowchart of a method for estimating the rotor temperature of a dual three-phase permanent magnet synchronous motor provided by an embodiment of the present invention.

[0023] Figure 2 FIG. is a block diagram of a phase-locked loop structure provided by an embodiment of the present invention.

[0024] Figure 3 FIG. is a schematic overall flowchart of a method for estimating the rotor temperature of a dual three-phase permanent magnet synchronous motor provided by an embodiment of the present invention.

[0025] Figure 4 FIG. is a schematic structural diagram of a device for estimating the rotor temperature of a dual three-phase permanent magnet synchronous motor provided by an embodiment of the present invention.

[0026] Figure 5 FIG. is a schematic physical structure diagram of an electronic device provided by an embodiment of the present invention. Specific Embodiments

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention with reference to the drawings in 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 without creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0028] It should be noted that real-time estimation of the rotor temperature of a dual three-phase permanent magnet synchronous motor can ensure the reliable operation of the flywheel energy storage system, which has very important theoretical and practical significance. Existing rotor temperature estimation schemes for dual three-phase permanent magnet synchronous motors include the lumped parameter thermal network model method, the finite element thermal model, the signal injection method, and the flux linkage model method.

[0029] Among them, the lumped parameter thermal network model method equivalentizes the points with similar temperatures in the motor into one node, and the nodes are connected by thermal resistances. The materials of different parts are replaced by heat capacities to obtain a thermal network model for the temperature distribution of each node. By measuring easily obtainable temperature values such as the stator temperature and the ambient temperature, and combining the heat loss and heat conduction characteristics of the motor, the rotor temperature is calculated using the thermal network model. However, this method requires an accurate motor loss distribution model, and the model complexity is relatively high.

[0030] The finite element thermal model establishes the thermal field model of the motor based on the geometric structure, material properties, and operating conditions of the motor using the finite element method. By numerically solving the heat conduction equation, the temperature distribution inside the motor can be obtained, thereby obtaining the rotor temperature. This method has high calculation accuracy, but the calculation cost is also very high, requiring a long calculation time and a large amount of calculation resources.

[0031] The signal injection method includes the high-frequency signal injection method and DC signal injection. Among them, the high-frequency signal injection method injects a high-frequency voltage or current signal into the stator winding of the motor, and estimates the rotor temperature by detecting the response of the rotor to the high-frequency signal. For example, when a high-frequency signal is injected, the change in the high-frequency resistance in the rotor winding is measured. Since the rotor resistance has a certain relationship with temperature, the rotor temperature can be deduced. However, this method will generate torque ripple, causing additional power loss and NVH (noise, vibration, and harshness) problems, and is effective for rotors with surface-mounted permanent magnets. If the permanent magnets are located inside the rotor lamination, its accuracy will be reduced. DC signal injection injects a DC signal on the direct axis of the motor, obtains the rotor flux linkage information by measuring the response of the motor, and then estimates the rotor temperature in combination with the relationship between the flux linkage and temperature. However, this method requires a relatively accurate understanding of the parameters of the motor, otherwise it will affect the accuracy of temperature estimation.

[0032] The flux linkage model method establishes a flux linkage observer of a continuous model based on the voltage equation in the d-q axis coordinate system, introduces the difference between the estimated current and the actual current as feedback, establishes the corresponding relationship between the rotor temperature and the flux linkage, and estimates the real-time rotor temperature according to the value of the flux linkage observer. This method has a large application range and does not require high processing power of the controller CPU. However, the accuracy of this method is affected by the change of the stator resistance, system noise, and measurement noise.

[0033] Considering this, the present invention proposes a new method for estimating the rotor temperature of a dual three-phase permanent magnet synchronous motor, which is applied to a flywheel energy storage system. Specifically, Figure 1 The flowchart of the method for estimating the rotor temperature of the dual three-phase permanent magnet synchronous motor provided by the embodiment of the present invention is shown.

[0034] As Figure 1 shown, the method includes steps S110-S140. The following will describe steps S110-S140 and related steps in detail.

[0035] S110, based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system and the second-order generalized integrator, obtain the filtered value of the stator flux linkage.

[0036] It is easy to understand that after the Clark transformation in the vector space decoupling of the dual three-phase permanent magnet synchronous motor, the dual three-phase permanent magnet synchronous motor can be equivalent to three mutually orthogonal sub-planes, namely the α-β sub-plane (two-phase stationary coordinate system), the d-q sub-plane (two-phase rotating coordinate system), and the x-y sub-plane.

[0037] Among these three mutually orthogonal sub-planes, the α-axis coincides with the A-phase coordinate axis, and the β-axis lags behind the α-axis by 90° counterclockwise. Among them, only the α-β sub-plane participates in the electromechanical energy conversion of the motor, and the fundamental wave and the 12k±1 (k = 1, 2, 3…) harmonics are projected onto this plane. The voltage equation of the α-β sub-plane is as follows in Equation (1).

[0038] (1).

[0039] In Equation (1), 、 represent the stator voltage of the dual three-phase permanent magnet synchronous motor in the α-β sub-plane, represents the stator resistance of the dual three-phase permanent magnet synchronous motor, 、 represent the stator current of the dual three-phase permanent magnet synchronous motor in the α-β sub-plane, 、 represent the stator flux linkage of the dual three-phase permanent magnet synchronous motor in the α-β sub-plane.

[0040] Furthermore, based on the voltage equation (1) of the α-β sub-plane, the traditional integral is replaced by a second-order generalized integral to obtain the filtered value of the stator flux linkage.

[0041] Specifically, first, based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system, the estimated value of the stator flux linkage is estimated through the stator flux linkage estimation model. Among them, the stator flux linkage estimation model is defined as follows in Equation (2).

[0042] (2).

[0043] In Equation (2), 、 represent the estimated value of the stator flux linkage, 、 represent the stator voltage of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system, represents the stator resistance of the dual three-phase permanent magnet synchronous motor, 、 represent the stator current of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system.

[0044] In the stator flux linkage estimation model, its input is the stator voltage of the α-β sub-plane (two-phase stationary coordinate system) and stator current , that is, the stator voltage and stator current of the dual three-phase permanent magnet synchronous motor under two-phase stationary conditions; its output is the estimated value of the stator flux linkage and .

[0045] Then, based on the second-order generalized integrator, according to the estimated value of the stator flux linkage, the filtered value of the stator flux linkage is obtained. Among them, the transfer function of the second-order generalized integrator is as shown in the following mathematical expression (3).

[0046] (3).

[0047] In formula (3), represents the transfer function of the second-order generalized integrator, represents the output of the transfer function, represents the input of the transfer function, represents the damping coefficient, represents the resonant angular frequency, represents the complex variable. The input of the second-order generalized integrator is the estimated value of the stator flux linkage and , and its output is the filtered value of the stator flux linkage and .

[0048] After obtaining the filtered value of the stator flux linkage based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system and the second-order generalized integrator in step S110, further, step S120 is executed.

[0049] S120, according to the filtered value of the stator flux linkage, a phase-locked loop is used to obtain the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor.

[0050] It is easy to understand that Figure 2 shows the block diagram of the phase-locked loop provided by the embodiment of the present invention. According to Figure 2 it can be seen that the input of the phase-locked loop is the filtered value of the stator flux linkage and , and its output is the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor and the rotating magnetic field angle .

[0051] In the solution process, first calculate the amplitude of the filtered value of the stator flux linkage. This step is to obtain a normalized denominator (denominator, simply denoted as "den" in the figure) for subsequent normalization operations. The filtered value of the stator flux linkage and are respectively multiplied by and Multiply (the "×" symbol in the figure represents the multiplication operation) to obtain the numerator (abbreviated as "num" in the figure). Then, respectively, and are normalized by dividing them by the estimated stator flux linkage amplitude, and the negative of the two is taken and added to obtain the error signal of the PI regulator. This signal passes through the PI regulator to obtain the estimated synchronous angular frequency , and the result is integrated to obtain the estimated rotating magnetic field angle , and this angle needs to be fed back to the aforementioned and during the calculation.

[0052] After obtaining the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor by using a phase-locked loop according to the filtered value of the stator flux linkage in step S120, further, step S130 is executed.

[0053] S130. Estimate the permanent magnet flux linkage based on the voltage equation of the dual three-phase permanent magnet synchronous motor under vector space decoupling and the synchronous angular frequency.

[0054] It is easy to understand that after the Clark transformation in the vector space decoupling of the dual three-phase permanent magnet synchronous motor, the voltage equation of the dual three-phase permanent magnet synchronous motor under vector space decoupling is obtained, that is, the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system. Specifically, it can be seen in the following formula (4).

[0055] (4).

[0056] In formula (4), and are the stator voltages of the dual three-phase permanent magnet synchronous motor in the d-q coordinate system (two-phase rotating coordinate system), and are the stator currents of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, is the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor, and are the stator inductances of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, is the permanent magnet flux linkage, , , , ,, are the stator voltage, stator current, and stator inductance in the x-y sub-plane respectively.

[0057] According to the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system and the synchronous angular frequency, the permanent magnet flux linkage can be estimated.

[0058] Specifically, first, according to the voltage equation and synchronous angular frequency of the dual-three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, a reduced-order permanent magnet flux linkage observation state equation is constructed, as shown in Equation (5) below for details.

[0059] (5).

[0060] In Equation (5), 、 represent the stator currents of the dual-three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, 、 represent the stator inductances of the dual-three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the stator voltage of the dual-three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the stator resistance of the dual-three-phase permanent magnet synchronous motor, represents the synchronous angular frequency of the dual-three-phase permanent magnet synchronous motor, represents the permanent magnet flux linkage of the dual-three-phase permanent magnet synchronous motor.

[0061] In the reduced-order permanent magnet flux linkage observation state equation (5), its input is the stator voltage in the two-phase rotating coordinate system, and the output is the stator current in the two-phase rotating coordinate system. That is to say, according to the above reduced-order permanent magnet flux linkage observation state equation (5), the stator current in the two-phase rotating coordinate system can be solved.

[0062] Furthermore, select the stator current and the permanent magnet flux linkage in the two-phase rotating coordinate system as state variables , discretize the Kalman filter equation, and the permanent magnet flux linkage can be estimated. Among them, the discretization process of the Kalman filter equation is as shown in Equations (6)-(11) below.

[0063] (6).

[0064] (7).

[0065] (8).

[0066] (9).

[0067] (10).

[0068] (11).

[0069] In Equations (6)-(11), represents the state prediction value, represents the state transition matrix, represents the optimal state estimate value at the previous moment, , represents the q-axis stator voltage of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the q-axis stator current of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the estimated synchronous angular frequency of the dual three-phase permanent magnet synchronous motor, represents the sampling moment, represents the sampling time, 、 respectively represent the q-axis stator inductance and d-axis stator inductance of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the predicted value of the error covariance matrix, represents the optimal estimated value of the error covariance matrix at the previous moment, represents the system noise covariance matrix, represents the Kalman filter gain matrix, represents the output matrix, represents the measurement error covariance matrix, represents the actual measured current, represents the stator resistance of the dual three-phase permanent magnet synchronous motor.

[0070] After estimating the permanent magnet flux linkage based on the voltage equation and synchronous angular frequency of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system in step S130, step S140 is executed.

[0071] S140, calculate the estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor according to the permanent magnet flux linkage.

[0072] It is easy to understand that the permanent magnet flux linkage changes with the change of the magnet temperature. For the corresponding magnetic material, its thermal constant of the magnet is , which is a known quantity. Furthermore, the calculation formula for the estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor is as follows in equation (12).

[0073] (12)。

[0074] In equation (12), represents the estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor, represents the temperature, represents the estimated value of the permanent magnet flux linkage at time represents the permanent magnet flux linkage value at temperature , represents the thermal constant of the permanent magnet.

[0075] It should be noted that in the method for estimating the rotor temperature of a dual three-phase permanent magnet synchronous motor provided in the embodiments of the present invention, the dual three-phase permanent magnet synchronous motor does not have a speed measurement device, such as a speed sensor.

[0076] In this embodiment, based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system and the second-order generalized integrator, the filtered value of the stator flux linkage is obtained. Then, based on the filtered value of the stator flux linkage, the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor is obtained by using a phase-locked loop. Furthermore, based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system and the synchronous angular frequency, the permanent magnet flux linkage is estimated. Thus, according to the permanent magnet flux linkage, the estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor is calculated. This method uses the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system combined with the second-order generalized integrator to estimate the synchronous speed (i.e., the synchronous angular frequency), and uses the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system to estimate the permanent magnet flux linkage, and then estimates the rotor temperature. It effectively reduces the interference of the sub-harmonics on the speed estimation, suppresses the influence of the system noise on the accuracy of the rotor temperature estimation, overcomes the defect that it is difficult to estimate the rotor temperature online in the prior art due to the inability to estimate the speed and the rotor flux linkage simultaneously, and realizes the high-precision estimation of the rotor temperature.

[0077] In some other embodiments, Figure 3 The overall flow diagram of the method for estimating the rotor temperature of the dual three-phase permanent magnet synchronous motor provided in the embodiments of the present invention is shown.

[0078] As Figure 3 shown, first, through the voltage model in the stationary coordinate system (i.e., the stator flux linkage estimation model described above), according to the stator voltage and the stator current in the α-β sub-plane (two-phase stationary coordinate system), the estimated values of the stator flux linkage and are estimated.

[0079] Then, through the second-order generalized integration (i.e., the second-order generalized integrator described above), according to the estimated values of the stator flux linkage and , combined with the resonant angular frequency , the filtered values of the stator flux linkage and are obtained.

[0080] Immediately afterwards, according to the filtered values of the stator flux linkage and , a phase-locked loop is used to obtain the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor.

[0081] Subsequently, based on the constructed voltage model in the rotating coordinate system (i.e., the reduced-order permanent magnet flux observer state equation described above), the stator current in the two-phase rotating coordinate system is solved according to the stator voltage and stator current in the two-phase rotating coordinate system, as well as the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor. Specifically, the stator current in the two-phase rotating coordinate system is solved.

[0082] Furthermore, taking the stator current and the permanent magnet flux in the two-phase rotating coordinate system as state variables, the permanent magnet flux is estimated by discretizing the Kalman filter equation. Specifically, the permanent magnet flux is estimated.

[0083] Finally, based on the permanent magnet flux the estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor can be obtained. Specifically, the estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor can be obtained.

[0084] Corresponding to the method for estimating the rotor temperature of the dual three-phase permanent magnet synchronous motor described in each of the above embodiments, the present invention also provides a device for estimating the rotor temperature of the dual three-phase permanent magnet synchronous motor, which is applied to a flywheel energy storage system. Specifically, Figure 4 FIG. shows a schematic structural diagram of the device for estimating the rotor temperature of the dual three-phase permanent magnet synchronous motor provided by the embodiment of the present invention.

[0085] As Figure 4 shown, the device includes: a stator flux filtering value obtaining module 410, configured to obtain a stator flux filtering value based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system and a second-order generalized integrator; a synchronous angular frequency obtaining module 420, configured to obtain the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor by using a phase-locked loop according to the stator flux filtering value; a permanent magnet flux estimating module 430, configured to estimate the permanent magnet flux based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system and the synchronous angular frequency; and a rotor temperature estimated value calculating module 440, configured to calculate the estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor according to the permanent magnet flux.

[0086] In this embodiment, the stator flux filtering value acquisition module 410 obtains the stator flux filtering value based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system and the second-order generalized integrator. The synchronous angular frequency acquisition module 420 uses a phase-locked loop to obtain the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor according to the stator flux filtering value. Furthermore, the permanent magnet flux estimation module 430 estimates the permanent magnet flux based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system and the synchronous angular frequency. Thus, the rotor temperature estimation value calculation module 440 calculates the estimated rotor temperature of the dual three-phase permanent magnet synchronous motor according to the permanent magnet flux. This device uses the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system combined with the second-order generalized integrator to estimate the synchronous speed (i.e., the synchronous angular frequency), uses the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system to estimate the permanent magnet flux, and then estimates the rotor temperature, effectively reducing the interference of sub-harmonics on speed estimation, suppressing the influence of system noise on the accuracy of rotor temperature estimation, overcoming the defect of the prior art that it is difficult to estimate the rotor temperature online because the speed and rotor flux cannot be estimated simultaneously, and achieving high-precision estimation of the rotor temperature.

[0087] It should be noted that the dual three-phase permanent magnet synchronous motor rotor temperature estimation device provided in the embodiments of the present invention can be correspondingly referred to the dual three-phase permanent magnet synchronous motor rotor temperature estimation methods described in the above embodiments, and will not be elaborated here.

[0088] Figure 5 An example of the physical structure diagram of an electronic device is shown as Figure 5 As shown, the electronic device may include: a processor 510, a communication interface 520, a memory 530, and a communication bus 540. Among them, the processor 510, the communication interface 520, and the memory 530 complete communication with each other through the communication bus 540. The processor 510 can call the logical instructions in the memory 530 to execute the dual three-phase permanent magnet synchronous motor rotor temperature estimation method, and this method includes: obtaining the stator flux filtering value based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system and the second-order generalized integrator; obtaining the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor using a phase-locked loop according to the stator flux filtering value; estimating the permanent magnet flux based on the voltage equation of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system and the synchronous angular frequency; calculating the estimated rotor temperature of the dual three-phase permanent magnet synchronous motor according to the permanent magnet flux.

[0089] In addition, when the logical instructions in the above-mentioned memory 530 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs.

[0090] On the other hand, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is used to implement the rotor temperature estimation method for a dual-three-phase permanent magnet synchronous motor provided by the above-mentioned various methods. The method includes: obtaining a filtered value of the stator flux based on the voltage equation of the dual-three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system and a second-order generalized integrator; using a phase-locked loop to obtain the synchronous angular frequency of the dual-three-phase permanent magnet synchronous motor according to the filtered value of the stator flux; estimating the permanent magnet flux based on the voltage equation of the dual-three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system and the synchronous angular frequency; and calculating an estimated value of the rotor temperature of the dual-three-phase permanent magnet synchronous motor according to the permanent magnet flux.

[0091] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative labor.

[0092] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for estimating the rotor temperature of a dual-three-phase permanent magnet synchronous motor, which is applied to a flywheel energy storage system, is characterized in that The method includes: Based on the voltage equation of a dual three-phase permanent magnet synchronous motor in a two-phase stationary coordinate system and a second-order generalized integrator, obtaining a filtered value of the stator flux linkage; According to the filtered value of the stator flux linkage, using a phase-locked loop to obtain the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor; Based on the voltage equation of the dual three-phase permanent magnet synchronous motor in a two-phase rotating coordinate system and the synchronous angular frequency, estimating the permanent magnet flux linkage; According to the permanent magnet flux linkage, calculating an estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor.

2. The rotor temperature estimation method of the dual-three-phase permanent magnet synchronous motor according to claim 1, characterized in that The step of obtaining a filtered value of the stator flux linkage based on the voltage equation of a dual three-phase permanent magnet synchronous motor in a two-phase stationary coordinate system and a second-order generalized integrator includes: Based on the voltage equation of the dual three-phase permanent magnet synchronous motor in a two-phase stationary coordinate system, estimating an estimated value of the stator flux linkage through a stator flux linkage estimation model; Based on the second-order generalized integrator, obtaining the filtered value of the stator flux linkage according to the estimated value of the stator flux linkage.

3. The rotor temperature estimation method of the dual-three-phase permanent magnet synchronous motor according to claim 1, characterized in that The step of estimating the permanent magnet flux linkage based on the voltage equation of the dual three-phase permanent magnet synchronous motor in a two-phase rotating coordinate system and the synchronous angular frequency includes: According to the voltage equation of the dual three-phase permanent magnet synchronous motor in a two-phase rotating coordinate system and the synchronous angular frequency, constructing a reduced-order permanent magnet flux linkage observation state equation; According to the reduced-order permanent magnet flux linkage observation state equation, solving for the stator current in the two-phase rotating coordinate system; Using the stator current and the permanent magnet flux linkage in the two-phase rotating coordinate system as state variables to discretize the Kalman filter equation, obtaining the estimated permanent magnet flux linkage.

4. The rotor temperature estimation method of the dual-three-phase permanent magnet synchronous motor according to claim 2, characterized in that, The stator flux linkage estimation model is defined as follows: ； The transfer function of the second-order generalized integrator is defined as follows: ； Among them, and represent the estimated value of the stator flux linkage, and represent the stator voltage of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system, represents the stator resistance of the dual three-phase permanent magnet synchronous motor, and represent the stator current of the dual three-phase permanent magnet synchronous motor in the two-phase stationary coordinate system, represents the transfer function of the second-order generalized integrator, represents the output of the transfer function, represents the input of the transfer function, represents the damping coefficient, represents the resonant angular frequency, represents a complex variable.

5. The rotor temperature estimation method of the dual-three-phase permanent magnet synchronous motor according to claim 3, characterized in that The reduced-order permanent magnet flux linkage observation state equation is defined as follows: ； Among them, , represent the stator currents of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, , represent the stator inductances of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the stator voltage of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the stator resistance of the dual three-phase permanent magnet synchronous motor, represents the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor, represents the permanent magnet flux linkage of the dual three-phase permanent magnet synchronous motor.

6. The rotor temperature estimation method of the dual-three-phase permanent magnet synchronous motor according to claim 3, characterized in that The discretization process of the Kalman filter equation is as follows: ； ； ； ； ； Among them, represents the state prediction value, represents the state transition matrix, represents the optimal state estimate value at the previous moment, , represents the q-axis stator voltage of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the q-axis stator current of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the estimated synchronous angular frequency of the dual three-phase permanent magnet synchronous motor, represents the sampling moment, represents the sampling time, 、 respectively represent the q-axis stator inductance and d-axis stator inductance of the dual three-phase permanent magnet synchronous motor in the two-phase rotating coordinate system, represents the predicted value of the error covariance matrix, represents the optimal estimated value of the error covariance matrix at the previous moment, represents the system noise covariance matrix, represents the Kalman filter gain matrix, represents the output matrix, represents the measurement error covariance matrix, represents the actual measured current.

7. The rotor temperature estimation method of the dual-three-phase permanent magnet synchronous motor according to any one of claims 1-6, characterized in that The calculation formula for the estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor is as follows: ； Among them, represents the estimated value of the rotor temperature of the dual-three-phase permanent magnet synchronous motor, represents temperature, represents the estimated value of the permanent magnet flux linkage at time represents the permanent magnet flux linkage value when the temperature is , represents the thermal constant of the permanent magnet.

8. A rotor temperature estimation device for a dual-three-phase permanent magnet synchronous motor, applied to a flywheel energy storage system, characterized in that, The device includes: A filtered value acquisition module for the stator flux linkage, configured to obtain a filtered value of the stator flux linkage based on the voltage equation of a dual three-phase permanent magnet synchronous motor in a two-phase stationary coordinate system and a second-order generalized integrator; A synchronous angular frequency acquisition module, configured to obtain the synchronous angular frequency of the dual three-phase permanent magnet synchronous motor using a phase-locked loop according to the filtered value of the stator flux linkage; A permanent magnet flux linkage estimation module, configured to estimate the permanent magnet flux linkage based on the voltage equation of the dual three-phase permanent magnet synchronous motor in a two-phase rotating coordinate system and the synchronous angular frequency; A rotor temperature estimated value calculation module, configured to calculate an estimated value of the rotor temperature of the dual three-phase permanent magnet synchronous motor according to the permanent magnet flux linkage.

9. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the method for estimating the rotor temperature of a dual three-phase permanent magnet synchronous motor according to any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for estimating the rotor temperature of a dual three-phase permanent magnet synchronous motor according to any one of claims 1 to 7.

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