Method and device for determining rotor temperature of permanent magnet motor and electric vehicle
By obtaining the three-phase current in the permanent magnet motor and calculating the rotor electric angular velocity and flux linkage, the problem of low rotor temperature accuracy is solved, achieving high-precision temperature measurement and cost savings.
Patent Information
- Application Number
- CN202511502708.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-21
- Publication Date
- 2026-02-24
AI Technical Summary
In the existing technology, the rotor temperature accuracy of permanent magnet motors is low and the cost is high, which leads to power reduction and unstable operation.
By acquiring the three-phase current of the permanent magnet motor and converting it to determine the estimated direct-axis and quadrature-axis currents, the rotor electric angular velocity and flux linkage are calculated using the motor parameters. The rotor temperature is then determined by combining the mapping relationship, thus avoiding the use of rotary transformers and position sensors.
This improves the accuracy of rotor temperature, reduces hardware costs, ensures stable motor operation, and extends the service life.
Smart Images
Figure CN121567026A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of permanent magnet motor technology, and in particular to a method, apparatus for determining the rotor temperature of a permanent magnet motor and an electric vehicle. Background Technology
[0002] With the development of technology, electric vehicles are gaining increasing popularity among consumers due to their advantages such as quiet operation, comfortable ride, excellent driving performance, and energy efficiency. The power actuator of an electric vehicle is a permanent magnet motor. If the rotor temperature of this motor is too high, it may cause demagnetization, leading to reduced power, unstable operation, and a shorter lifespan. Therefore, it is necessary to accurately determine the rotor temperature of the permanent magnet motor and implement cooling measures when the temperature becomes too high.
[0003] Currently, a rotary transformer can be installed on a permanent magnet motor to obtain the motor's electrical angle. Based on this electrical angle, the motor's voltage equation, and a sliding diaphragm observer, the rotor temperature of the permanent magnet motor can be estimated. However, during operation, the accuracy of the electrical angle obtained by the rotary transformer is easily affected by the environment in which the permanent magnet motor operates, resulting in low accuracy of the acquired electrical angle, which in turn affects the rotor temperature of the permanent magnet motor. Furthermore, this method requires significant hardware investment and has a limited range of applications. Summary of the Invention
[0004] This application provides a method, apparatus, and electric vehicle for determining the rotor temperature of a permanent magnet motor, which solves the problems of low accuracy and high cost in obtaining the rotor temperature of a permanent magnet motor in the prior art.
[0005] In a first aspect, this application provides a method for determining the rotor temperature of a permanent magnet motor, applied to a motor controller. The method provided in this application includes: When the permanent magnet motor is in operation, obtain the three-phase current flowing through the stator of the permanent magnet motor; The three-phase current is converted to obtain the first estimated current on the predicted direct axis of the permanent magnet motor and the second estimated current on the predicted quadrature axis of the permanent magnet motor. There is a rotor electrical angle difference between the predicted direct axis and the actual direct axis of the permanent magnet motor. Based on the first estimated current, the second estimated current, and multiple preset first motor parameters of the permanent magnet motor, the rotor electric angular velocity that makes the rotor electric angle difference less than or equal to the set angle difference threshold is obtained. Based on the obtained rotor electric angular velocity, the estimated first current on the direct axis of the rotor magnetic poles of the permanent magnet motor, the estimated second current on the quadrature axis, and multiple preset second motor parameters of the permanent magnet motor, the rotor permanent magnet flux linkage of the permanent magnet motor is determined. The rotor temperature of the permanent magnet motor is determined based on the rotor permanent magnet flux linkage and the preset mapping relationship.
[0006] In some implementations, based on a first estimated current, a second estimated current, and a plurality of preset first motor parameters of the permanent magnet motor, a rotor electric angular velocity is obtained such that the rotor electric angle difference is less than or equal to a set angle difference threshold, including: Based on the first estimated current, the second estimated current, the pre-configured rotor electric angular velocity, and multiple first motor parameters of the preset permanent magnet motor, the rotor electric angle difference between the estimated direct axis of the rotor magnetic poles and the actual direct axis of the rotor magnetic poles is determined. If the rotor electrical angle difference is greater than the preset angle difference threshold, the configured rotor electrical angular velocity is updated, and the process returns to the step of determining the rotor electrical angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole based on the first estimated current, the second estimated current, the preset rotor electrical angular velocity, and multiple preset first motor parameters of the permanent magnet motor, until the rotor electrical angle difference is less than or equal to the angle difference threshold.
[0007] In some embodiments, the plurality of first motor parameters include a preset estimated first demand voltage on the direct axis, a preset estimated second demand voltage on the quadrature axis, a preset first inductance on the actual direct axis, a preset second inductance on the actual quadrature axis, and a preset stator resistance.
[0008] In some implementations, the rotor electrical angle difference between the estimated direct axis of the rotor poles and the actual direct axis of the rotor poles is determined based on a first estimated current, a second estimated current, a pre-configured rotor electrical angular velocity, and multiple preset first motor parameters of the permanent magnet motor, including: According to the formula Determine the rotor electrical angle difference between the estimated direct axis of the rotor magnetic poles and the actual direct axis of the rotor magnetic poles, where, , For the preset estimated first required voltage on the direct axis, The second required voltage on the preset quadrature axis is given by r, and r is the preset stator resistance. Here, p represents the pre-configured rotor electric angular velocity, and p is the differential operator symbol. The first inductance on the actual direct axis is preset. The second inductance is the preset actual cross-axis. For the first estimated current, The second estimated current is given, and E is the extended back electromotive force of the permanent magnet motor. This is the rotor electrical angle difference.
[0009] In some embodiments, the second motor parameters include a preset estimated second required voltage on the quadrature axis, a preset second inductance on the actual quadrature axis, a preset stator resistance, and a preset first inductance on the actual direct axis. Based on the obtained rotor electric angular velocity, the estimated first current on the direct axis of the permanent magnet motor's rotor poles, the estimated second current on the quadrature axis, and multiple preset second motor parameters of the permanent magnet motor, the rotor permanent magnet flux linkage of the permanent magnet motor is determined, including: The extended back electromotive force of the permanent magnet motor is determined based on the estimated second required voltage on the quadrature axis, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, the stator resistance, and the first inductance on the actual direct axis. The rotor permanent magnet flux linkage of the permanent magnet motor is determined based on the extended back electromotive force, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, and the first inductance on the actual direct axis.
[0010] In some implementations, the extended back electromotive force of the permanent magnet motor is determined based on the estimated second required voltage on the quadrature axis, the obtained rotor electrical angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, the stator resistance, and the first inductance on the actual direct axis, including: According to the formula Determine the extended back electromotive force (EMF) of the permanent magnet motor, where E is the extended back EMF of the permanent magnet motor. To estimate the second required voltage on the quadrature axis, To obtain the rotor electric angular velocity, This is the second inductance on the actual quadrature axis. For the first estimated current, For the second estimated current, r is the stator resistance, and p is the differential operator symbol. This is the first inductance on the actual direct axis.
[0011] In some implementations, the rotor permanent magnet flux linkage of the permanent magnet motor is determined based on the extended back electromotive force, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, and the first inductance on the actual direct axis, including: According to the formula / Determine the rotor permanent magnet flux linkage of the permanent magnet motor, where, Let be the permanent magnet flux linkage of the rotor of the permanent magnet motor, and E be the extended back electromotive force of the permanent magnet motor. To obtain the rotor electric angular velocity, For the first estimated current, For the second estimated current, p is the symbol for the differential operator. The first inductance on the actual direct axis is preset. The second inductance is the preset actual cross-axis.
[0012] In some implementations, the three-phase current is converted to obtain a first estimated current on the direct axis of the permanent magnet motor and a second estimated current on the quadrature axis of the permanent magnet motor, including: According to the formula Determine the first conversion current on the coordinate axis that coincides with the U-phase of the three-phase stator. And the second conversion current on the coordinate axis perpendicular to the U-phase of the three-phase stator. , The current in phase A of the stator. For the B-phase current of the stator, This refers to the C-phase current of the stator. According to the formula The first estimated current on the direct axis of the permanent magnet motor is obtained. According to the formula This yields the second estimated current on the quadrature axis, where, For the first estimated current, For the first estimated current, This is the preset rotor electrical angle of the permanent magnet motor.
[0013] In some implementations, the range of the set angle difference threshold is 0 degrees to 3 degrees.
[0014] In some embodiments, after determining the rotor temperature of the permanent magnet motor based on the rotor permanent magnet flux linkage and a preset mapping relationship, the method provided in this application further includes: If the rotor temperature of the permanent magnet motor exceeds the set temperature threshold, the permanent magnet motor will be controlled to reduce its operating power.
[0015] In some embodiments, before acquiring the three-phase current flowing through the stator of the permanent magnet motor while the permanent magnet motor is in operation, the method provided in this application further includes: Establish the mapping relationship between the rotor permanent magnet flux linkage and rotor temperature of the permanent magnet motor.
[0016] Secondly, this application also provides a rotor temperature determination device for a permanent magnet motor, applied to a motor controller. The device provided in this application includes: The current conversion unit is used to convert the three-phase current flowing through the stator of the permanent magnet motor when the permanent magnet motor is in operation, so as to obtain the first estimated current on the direct axis and the second estimated current on the quadrature axis of the rotor magnetic poles of the permanent magnet motor. The electrical angle difference determination unit is used to determine the rotor electrical angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole based on the first estimated current, the second estimated current, the pre-configured rotor electrical angular velocity, and multiple preset motor parameters of the permanent magnet motor. The electric angular velocity configuration unit is used to update the configured rotor electric angular velocity if the rotor electric angle difference is greater than the preset angle difference threshold, and return to the step of determining the rotor electric angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole based on the first estimated current, the second estimated current, the preset rotor electric angular velocity, and multiple preset motor parameters of the permanent magnet motor, until the rotor electric angle difference is less than or equal to the angle difference threshold. The permanent magnet flux linkage determination unit is used to determine the rotor permanent magnet flux linkage of the permanent magnet motor based on the obtained rotor electric angular velocity, the estimated first estimated current on the direct axis of the rotor magnetic poles of the permanent magnet motor, the estimated second estimated current on the quadrature axis, and multiple preset motor parameters of the permanent magnet motor. The rotor temperature determination unit is used to determine the rotor temperature of the permanent magnet motor based on the rotor permanent magnet flux linkage and a preset mapping relationship.
[0017] Thirdly, this application also provides an electric vehicle equipped with a motor controller, which is used to execute the method provided in the first aspect of this application.
[0018] Fourthly, this application also provides a storage medium storing a computer program, which, when executed by a processor, causes the computer to perform the method provided in the first aspect of this application.
[0019] Fifthly, this application also provides a computer program product, including a computer program that, when run, causes a motor controller to perform the method as described in the first aspect of this application.
[0020] This application provides a method, apparatus, and electric vehicle for determining the rotor temperature of a permanent magnet motor. Based on a first estimated current, a second estimated current, and multiple preset first motor parameters of the permanent magnet motor, a rotor electrical angular velocity is obtained that results in a rotor electrical angle difference less than or equal to a preset angle difference threshold. Then, based on the obtained rotor electrical angular velocity, a first estimated current on the predicted direct axis of the permanent magnet motor's rotor poles, a second estimated current on the predicted quadrature axis, and multiple preset second motor parameters of the permanent magnet motor, the rotor permanent magnet flux linkage of the permanent magnet motor is determined. Finally, the rotor temperature of the permanent magnet motor is determined based on the rotor permanent magnet flux linkage and a preset mapping relationship. This method eliminates the need for a rotary transformer and position sensors to obtain the rotor temperature of the permanent magnet motor, improving the accuracy of the obtained rotor temperature and saving hardware costs. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is a schematic diagram showing the positional relationship of the various axes provided in the embodiments of this application; Figure 2 One of the flowcharts for a method of determining the rotor temperature of a permanent magnet motor provided in an embodiment of this application; Figure 3 A second flowchart illustrating the method for determining the rotor temperature of a permanent magnet motor provided in this application embodiment; Figure 4 A functional block diagram of the rotor temperature determination device for a permanent magnet motor provided in an embodiment of this application. Detailed Implementation
[0023] Embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.
[0024] The accompanying drawings illustrate various structural schematics according to embodiments of the present disclosure. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.
[0025] In the context of this disclosure, when a layer / element is referred to as being "above" another layer / element, the layer / element may be directly above the other layer / element, or there may be an intermediate layer / element between them. Additionally, if a layer / element is "above" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element.
[0026] First, let me explain the terms used in this application: Direct axis: also known as d-axis, is the direction of the N pole of the rotor magnetic poles of a permanent magnet synchronous motor; The intersection axis, also known as the q-axis, is the direction of the positive d-axis rotated 90° counterclockwise. α-axis: A coordinate axis that coincides with the U-phase of the three-phase stator and is used for Clarke transformation; β-axis: A coordinate axis perpendicular to the U-phase of the three-phase stator, used for Clarke transformation; γ-axis: The estimated position of the d-axis, differing from the previous d-axis position by θerr; δ-axis: The estimated position of the q-axis, which differs from the previous q-axis position by θerr.
[0027] The positions of the aforementioned axes can be as follows: Figure 1 As shown.
[0028] The technical solutions of this application and how they solve the aforementioned technical problems will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.
[0029] Please see Figure 2 This application provides a method for determining the rotor temperature of a permanent magnet motor, applied to a motor controller. For example... Figure 2 As shown, the method provided in this application embodiment includes S201-S205, wherein, S201: When the permanent magnet motor is in operation, obtain the three-phase current flowing through the stator of the permanent magnet motor.
[0030] For example, the three-phase current flowing through the stator of a permanent magnet motor can be collected by a current sensor.
[0031] S202: Convert the three-phase current to obtain the first estimated current on the predicted direct axis of the permanent magnet motor and the second estimated current on the predicted quadrature axis of the permanent magnet motor. There is a rotor electrical angle difference between the predicted direct axis and the actual direct axis of the permanent magnet motor.
[0032] For example, S202 can be specifically implemented as: according to the formula Determine the first conversion current on the coordinate axis that coincides with the U-phase of the three-phase stator. And the second conversion current on the coordinate axis perpendicular to the U-phase of the three-phase stator. , The current in phase A of the stator. For the B-phase current of the stator, For the C-phase current of the stator; according to the formula The first estimated current on the direct axis of the permanent magnet motor is obtained; according to the formula... This yields the second estimated current on the quadrature axis, where, For the first estimated current, For the first estimated current, This is the preset rotor electrical angle of the permanent magnet motor.
[0033] S203: Based on the first estimated current, the second estimated current, and multiple preset first motor parameters of the permanent magnet motor, obtain the rotor electric angular velocity that makes the rotor electric angle difference less than or equal to the set angle difference threshold.
[0034] Furthermore, such as Figure 3 As shown, S203 can be specifically implemented as follows: S301: Based on the first estimated current, the second estimated current, the pre-configured rotor electric angular velocity, and multiple first motor parameters of the preset permanent magnet motor, determine the rotor electric angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole.
[0035] In some implementations, the plurality of first motor parameters include a preset estimated first demand voltage on the direct axis, a preset estimated second demand voltage on the quadrature axis, a preset first inductance on the actual direct axis, a preset second inductance on the actual quadrature axis, and a preset stator resistance. Exemplarily, this can be based on a formula... This involves determining the rotor electrical angle difference between the estimated direct axis of the rotor magnetic poles and the actual direct axis of the rotor magnetic poles. , For the preset estimated first required voltage on the direct axis, The second required voltage on the preset quadrature axis is given by r, and r is the preset stator resistance. Here, p represents the pre-configured rotor electric angular velocity, and p is the differential operator symbol. The first inductance on the actual direct axis is preset. The second inductance is the preset actual cross-axis. For the first estimated current, The second estimated current is given, and E is the extended back electromotive force of the permanent magnet motor. This is the rotor electrical angle difference.
[0036] Understandably, the above formula can accurately determine the rotor electrical angle difference between the estimated direct axis of the rotor magnetic poles and the actual direct axis of the rotor magnetic poles.
[0037] Among them, the formula The derivation process is as follows: The current dq-axis voltage equation is: , , For the first required voltage on the actual direct axis, This is the second required voltage on the actual quadrature axis. This represents the actual current along the direct axis of the permanent magnet motor. This represents the actual quadrature-axis current of the permanent magnet motor. For the direct-axis magnetic flux of a permanent magnet motor. For the quadrature axis magnetic flux of a permanent magnet motor, This refers to the permanent magnet flux linkage of the rotor in a permanent magnet motor.
[0038] Furthermore, imaginary numbers are defined separately. , for: ; Substituting the above dq-axis voltage equation into the formula , can be obtained .
[0039] Furthermore, the formula Substitute into the formula , can be obtained + .
[0040] Understandably, since the actual direct axis, the actual quadrature axis, and the estimated direct axis and the estimated quadrature axis rotate synchronously, we have: , and All are imaginary numbers.
[0041] The equation Substitute into + From this, we can obtain + Multiply both sides of the equation by The formula is obtained. + * .
[0042] Understandably, = When the actual direct axis, the actual quadrature axis, and the estimated direct axis and the estimated quadrature axis rotate synchronously, =0. Therefore, the equation / calculation is correct. + * It can be simplified to: E , where E = + Finally, Decompose the equations onto the predicted direct axis and the predicted intersection axis to obtain the formula. .
[0043] S302: Determine whether the rotor electrical angle difference is greater than the preset angle difference threshold. If yes, execute S303; otherwise, execute S304.
[0044] For example, the range of the angle difference threshold is set to 0 degrees to 3 degrees.
[0045] S303: Update the configured rotor electric angular velocity and return to execute S301.
[0046] S304: Get the current configured rotor electric angular velocity.
[0047] Understandably, based on the above S301-S304, the rotor electric angular velocity of the current configuration can be accurately obtained.
[0048] S204: Determine the permanent magnet flux linkage of the rotor of the permanent magnet motor based on the obtained rotor electric angular velocity, the estimated first current on the direct axis of the rotor magnetic poles of the permanent magnet motor, the estimated second current on the quadrature axis, and multiple preset second motor parameters of the permanent magnet motor.
[0049] In some embodiments, the second motor parameters include a preset estimated second required voltage on the quadrature axis, a preset second inductance on the actual quadrature axis, a preset stator resistance, and a preset first inductance on the actual direct axis. S204 can be specifically implemented as follows: Step 1: Determine the extended back electromotive force of the permanent magnet motor based on the estimated second required voltage on the quadrature axis, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, the stator resistance, and the first inductance on the actual direct axis.
[0050] For example, according to the formula Determine the extended back electromotive force (EMF) of the permanent magnet motor. Where E is the extended back EMF of the permanent magnet motor. To estimate the second required voltage on the quadrature axis, To obtain the rotor electric angular velocity, This is the second inductance on the actual quadrature axis. For the first estimated current, For the second estimated current, r is the stator resistance, and p is the differential operator symbol. This is the first inductance on the actual direct axis.
[0051] Step 2: Determine the rotor permanent magnet flux linkage of the permanent magnet motor based on the extended back electromotive force, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, and the first inductance on the actual direct axis.
[0052] Step 2 can be specifically implemented as follows: based on the formula / The rotor permanent magnet flux linkage of the permanent magnet motor is determined. Let be the permanent magnet flux linkage of the rotor of the permanent magnet motor, and E be the extended back electromotive force of the permanent magnet motor. To obtain the rotor electric angular velocity, For the first estimated current, For the second estimated current, p is the symbol for the differential operator. The first inductance on the actual direct axis is preset. The second inductance is the preset actual cross-axis.
[0053] S205: Determine the rotor temperature of the permanent magnet motor based on the rotor permanent magnet flux linkage and the preset mapping relationship.
[0054] In some embodiments, prior to S201, the method provided in this application further includes: establishing a mapping relationship (such as a relationship mapping table) between the rotor permanent magnet flux linkage and the rotor temperature of the permanent magnet motor. For example, the rotor temperature of the permanent magnet motor can be found from a preset relationship mapping table based on the rotor permanent magnet flux linkage.
[0055] Furthermore, the method provided in this application embodiment also includes: if the rotor temperature of the permanent magnet motor is greater than a set temperature threshold, controlling the permanent magnet motor to reduce its operating power. This reduces the rotor temperature of the permanent magnet motor, thereby extending its service life.
[0056] In summary, this application provides a method for determining the rotor temperature of a permanent magnet motor. Based on a first estimated current, a second estimated current, and multiple preset first motor parameters of the permanent magnet motor, a rotor electrical angular velocity is obtained that results in a rotor electrical angle difference less than or equal to a set angle difference threshold. Then, based on the obtained rotor electrical angular velocity, the first estimated current on the predicted direct axis of the permanent magnet motor's rotor poles, the second estimated current on the predicted quadrature axis, and multiple preset second motor parameters of the permanent magnet motor, the rotor permanent magnet flux linkage of the permanent magnet motor is determined. Finally, the rotor temperature of the permanent magnet motor is determined based on the rotor permanent magnet flux linkage and a preset mapping relationship. This method eliminates the need for a rotary transformer and position sensors to obtain the rotor temperature of the permanent magnet motor, improving the accuracy of the obtained rotor temperature and saving hardware costs.
[0057] In addition, such as Figure 4 As shown, this application embodiment also provides a rotor temperature determination device for a permanent magnet motor, applied to a motor controller. It should be noted that the basic principle and technical effects of the rotor temperature determination device for a permanent magnet motor provided in this application embodiment are the same as those in the above embodiments. For the sake of brevity, any parts not mentioned in this application embodiment can be referred to the corresponding content in the above embodiments. For example... Figure 4 As shown, the device provided in this application embodiment includes a current conversion unit, an electrical angle difference determination unit, an electrical angular velocity configuration unit, a permanent magnet flux linkage determination unit, and a rotor temperature determination unit, wherein... The current conversion unit is used to convert the three-phase current flowing through the stator of the permanent magnet motor when the permanent magnet motor is in operation, so as to obtain the first estimated current on the direct axis and the second estimated current on the quadrature axis of the rotor magnetic poles of the permanent magnet motor. The electrical angle difference determination unit is used to determine the rotor electrical angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole based on the first estimated current, the second estimated current, the pre-configured rotor electrical angular velocity, and multiple preset motor parameters of the permanent magnet motor. The electric angular velocity configuration unit is used to update the configured rotor electric angular velocity if the rotor electric angle difference is greater than the preset angle difference threshold, and return to the step of determining the rotor electric angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole based on the first estimated current, the second estimated current, the preset rotor electric angular velocity, and multiple preset motor parameters of the permanent magnet motor, until the rotor electric angle difference is less than or equal to the angle difference threshold. The permanent magnet flux linkage determination unit is used to determine the rotor permanent magnet flux linkage of the permanent magnet motor based on the obtained rotor electric angular velocity, the estimated first estimated current on the direct axis of the rotor magnetic poles of the permanent magnet motor, the estimated second estimated current on the quadrature axis, and multiple preset motor parameters of the permanent magnet motor. The rotor temperature determination unit is used to determine the rotor temperature of the permanent magnet motor based on the rotor permanent magnet flux linkage and a preset mapping relationship.
[0058] In some embodiments, the plurality of first motor parameters include a preset estimated first demand voltage on the direct axis, a preset estimated second demand voltage on the quadrature axis, a preset first inductance on the actual direct axis, a preset second inductance on the actual quadrature axis, and a preset stator resistance.
[0059] In some implementations, the electrical angle difference determination unit is specifically used to determine the electrical angle difference based on a formula. This involves determining the rotor electrical angle difference between the estimated direct axis of the rotor magnetic poles and the actual direct axis of the rotor magnetic poles. , For the preset estimated first required voltage on the direct axis, The second required voltage on the preset quadrature axis is given by r, and r is the preset stator resistance. Here, p represents the pre-configured rotor electric angular velocity, and p is the differential operator symbol. The first inductance on the actual direct axis is preset. The second inductance is the preset actual cross-axis. For the first estimated current, The second estimated current is given, and E is the extended back electromotive force of the permanent magnet motor. This refers to the rotor electrical angle difference. It should be noted that when... When = 0, it satisfies .
[0060] In some embodiments, the second motor parameters include a preset estimated second required voltage on the quadrature axis, a preset second inductance on the actual quadrature axis, a preset stator resistance, and a preset first inductance on the actual direct axis. The permanent magnet flux linkage determination unit is specifically used to determine the extended back electromotive force (EMF) of the permanent magnet motor based on the estimated second required voltage on the quadrature axis, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, the stator resistance, and the first inductance on the actual direct axis; and to determine the rotor permanent magnet flux linkage of the permanent magnet motor based on the extended back EMF, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, and the first inductance on the actual direct axis.
[0061] In some implementations, the permanent magnet flux linkage determination unit is specifically used to determine the flux linkage based on a formula. Determine the extended back electromotive force (EMF) of the permanent magnet motor. Where E is the extended back EMF of the permanent magnet motor. To estimate the second required voltage on the quadrature axis, To obtain the rotor electric angular velocity, This is the second inductance on the actual quadrature axis. For the first estimated current, For the second estimated current, r is the stator resistance, and p is the differential operator symbol. This is the first inductance on the actual direct axis.
[0062] In some implementations, the permanent magnet flux linkage determination unit is specifically used to determine the flux linkage based on a formula. / The rotor permanent magnet flux linkage of the permanent magnet motor is determined. Let be the permanent magnet flux linkage of the rotor of the permanent magnet motor, and E be the extended back electromotive force of the permanent magnet motor. To obtain the rotor electric angular velocity, For the first estimated current, For the second estimated current, p is the symbol for the differential operator. The first inductance on the actual direct axis is preset. The second inductance is the preset actual cross-axis.
[0063] In some implementations, the current conversion unit is specifically used to convert the current according to the formula. Determine the first conversion current on the coordinate axis that coincides with the U-phase of the three-phase stator. And the second conversion current on the coordinate axis perpendicular to the U-phase of the three-phase stator. , The current in phase A of the stator. For the B-phase current of the stator, For the C-phase current of the stator; according to the formula The first estimated current on the direct axis of the permanent magnet motor is obtained; according to the formula... This yields the second estimated current on the predicted quadrature axis. Wherein, For the first estimated current, For the first estimated current, This is the preset rotor electrical angle of the permanent magnet motor.
[0064] In addition, this application also provides an electric vehicle equipped with a motor controller, which is used to execute the method provided in the above embodiments of this application.
[0065] In addition, this application embodiment also provides a storage medium storing a computer program, which, when executed by a processor, causes the computer to perform the method provided in the above embodiments of this application.
[0066] In addition, this application also provides a computer program product, including a computer program that, when run, causes a motor controller to perform the method as described in the above embodiments of this application.
[0067] The above description does not provide detailed technical specifications regarding the structure of each layer. However, those skilled in the art should understand that layers and regions of desired shapes can be formed using various technical means. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be advantageously combined.
[0068] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.
[0069] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.
Claims
1. A method for determining the rotor temperature of a permanent magnet motor, characterized in that, Applied to a motor controller, the method includes: When the permanent magnet motor is in operation, the three-phase current flowing through the stator of the permanent magnet motor is obtained; The three-phase current is converted to obtain the first estimated current on the estimated direct axis of the permanent magnet motor and the second estimated current on the estimated quadrature axis of the permanent magnet motor, wherein there is a rotor electrical angle difference between the estimated direct axis and the actual direct axis of the permanent magnet motor. Based on the first estimated current, the second estimated current, and a plurality of preset first motor parameters of the permanent magnet motor, a rotor electric angular velocity is obtained such that the rotor electric angle difference is less than or equal to a set angle difference threshold. Based on the obtained rotor electric angular velocity, the estimated first current on the direct axis of the rotor magnetic poles of the permanent magnet motor, the estimated second current on the quadrature axis, and the preset multiple second motor parameters of the permanent magnet motor, the rotor permanent magnet flux linkage of the permanent magnet motor is determined. The rotor temperature of the permanent magnet motor is determined based on the rotor permanent magnet flux linkage and the preset mapping relationship.
2. The method according to claim 1, characterized in that, The step of obtaining the rotor electric angular velocity such that the rotor electric angle difference is less than or equal to a set angle difference threshold based on the first estimated current, the second estimated current, and a plurality of preset first motor parameters of the permanent magnet motor includes: Based on the first estimated current, the second estimated current, the pre-configured rotor electric angular velocity, and the preset first motor parameters of the permanent magnet motor, the rotor electric angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole is determined. If the rotor electrical angle difference is greater than the preset angle difference threshold, the configured rotor electrical angular velocity is updated, and the process returns to the step of determining the rotor electrical angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole based on the first estimated current, the second estimated current, the preset rotor electrical angular velocity, and the preset multiple first motor parameters of the permanent magnet motor, until the rotor electrical angle difference is less than or equal to the angle difference threshold.
3. The method according to claim 2, characterized in that, The plurality of first motor parameters include a preset estimated first demand voltage on the direct axis, a preset estimated second demand voltage on the quadrature axis, a preset first inductance on the actual direct axis, a preset second inductance on the actual quadrature axis, and a preset stator resistance.
4. The method according to claim 3, characterized in that, The step of determining the rotor electrical angle difference between the estimated direct axis of the rotor magnetic poles and the actual direct axis of the rotor magnetic poles based on the first estimated current, the second estimated current, the pre-configured rotor electrical angular velocity, and multiple preset first motor parameters of the permanent magnet motor includes: According to the formula The rotor electrical angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole is determined, wherein, , For the preset estimated first required voltage on the direct axis, The second required voltage on the preset estimated quadrature axis is given by r, where r is the preset stator resistance. Here, p represents the pre-configured rotor electric angular velocity, and p is the differential operator symbol. The first inductance on the actual direct axis is the preset value. The second inductance on the preset actual quadrature axis, For the first estimated current, Let E be the second estimated current, and E be the extended back electromotive force of the permanent magnet motor. The rotor electrical angle difference is given.
5. The method according to claim 1, characterized in that, The second motor parameters include a preset estimated second required voltage on the quadrature axis, a preset second inductance on the actual quadrature axis, a preset stator resistance, and a preset first inductance on the actual direct axis. Determining the rotor permanent magnet flux linkage of the permanent magnet motor based on the obtained rotor electric angular velocity, the preset first estimated current on the direct axis of the rotor poles of the permanent magnet motor, the preset second estimated current on the quadrature axis, and the preset multiple second motor parameters of the permanent magnet motor includes: The extended back electromotive force of the permanent magnet motor is determined based on the estimated second required voltage on the quadrature axis, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, the stator resistance, and the first inductance on the actual direct axis. The rotor permanent magnet flux linkage of the permanent magnet motor is determined based on the extended back electromotive force, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, and the first inductance on the actual direct axis.
6. The method according to claim 5, characterized in that, The step of determining the extended back electromotive force of the permanent magnet motor based on the estimated second required voltage on the quadrature axis, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, the stator resistance, and the first inductance on the actual direct axis includes: According to the formula The extended back electromotive force of the permanent magnet motor is determined, where E is the extended back electromotive force of the permanent magnet motor. For the estimated second required voltage on the quadrature axis, The obtained rotor electric angular velocity, The second inductance on the actual quadrature axis, For the first estimated current, Let r be the second estimated current, r be the stator resistance, and p be the differential operator symbol. This is the first inductance on the actual direct axis.
7. The method according to claim 5, characterized in that, The step of determining the rotor permanent magnet flux linkage of the permanent magnet motor based on the extended back electromotive force, the obtained rotor electric angular velocity, the second inductance on the actual quadrature axis, the first estimated current, the second estimated current, and the first inductance on the actual direct axis includes: According to the formula / The rotor permanent magnet flux linkage of the permanent magnet motor is determined, wherein, Let E be the rotor permanent magnet flux linkage of the permanent magnet motor, and E be the extended back electromotive force of the permanent magnet motor. The obtained rotor electric angular velocity, For the first estimated current, Let p be the second estimated current, and p be the symbol for the differential operator. The first inductance on the actual direct axis is the preset value. The second inductance is the preset actual cross-axis.
8. The method according to claim 1, characterized in that, The conversion of the three-phase current to obtain the first estimated current on the direct axis of the permanent magnet motor and the second estimated current on the quadrature axis of the permanent magnet motor includes: According to the formula Determine the first conversion current on the coordinate axis that coincides with the U-phase of the three-phase stator. And the second conversion current on the coordinate axis perpendicular to the U-phase of the three-phase stator. , The current in phase A of the stator. For the B-phase current of the stator, This refers to the C-phase current of the stator. According to the formula The first estimated current on the direct axis of the permanent magnet motor is obtained. According to the formula This yields the second estimated current on the quadrature axis, where, For the first estimated current, For the first estimated current, The preset estimated rotor electrical angle of the permanent magnet motor.
9. The method according to any one of claims 1-8, characterized in that, The set angle difference threshold value ranges from 0 degrees to 3 degrees.
10. The method according to any one of claims 1-8, characterized in that, After determining the rotor temperature of the permanent magnet motor based on the rotor permanent magnet flux linkage and a preset mapping relationship, the method further includes: If the rotor temperature of the permanent magnet motor is greater than a set temperature threshold, the permanent magnet motor is controlled to reduce its operating power.
11. The method according to any one of claims 1-8, characterized in that, Before acquiring the three-phase current flowing through the stator of the permanent magnet motor while the permanent magnet motor is in operation, the method further includes: Establish a mapping relationship between the rotor permanent magnet flux linkage and the rotor temperature of the permanent magnet motor.
12. A rotor temperature determination device for a permanent magnet motor, characterized in that, Applied to a motor controller, the device includes: The current conversion unit is used to convert the three-phase current flowing through the stator of the permanent magnet motor when the permanent magnet motor is in operation, so as to obtain the first estimated current on the direct axis and the second estimated current on the quadrature axis of the rotor magnetic poles of the permanent magnet motor. An electrical angle difference determination unit is used to determine the rotor electrical angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole based on the first estimated current, the second estimated current, the pre-configured rotor electrical angular velocity, and multiple preset motor parameters of the permanent magnet motor. An electric angular velocity configuration unit is used to update the configured rotor electric angular velocity if the rotor electric angle difference is greater than a preset angle difference threshold, and return to the step of determining the rotor electric angle difference between the estimated direct axis of the rotor magnetic pole and the actual direct axis of the rotor magnetic pole based on the first estimated current, the second estimated current, the preset rotor electric angular velocity, and multiple preset motor parameters of the permanent magnet motor, until the rotor electric angle difference is less than or equal to the angle difference threshold. The permanent magnet flux linkage determination unit is used to determine the rotor permanent magnet flux linkage of the permanent magnet motor based on the obtained rotor electric angular velocity, the estimated first estimated current on the direct axis of the rotor magnetic poles of the permanent magnet motor, the estimated second estimated current on the quadrature axis, and multiple preset motor parameters of the permanent magnet motor. The rotor temperature determination unit is used to determine the rotor temperature of the permanent magnet motor based on the rotor permanent magnet flux linkage and a preset mapping relationship.
13. An electric vehicle, characterized in that, A motor controller is installed, which is used to perform the method according to any one of claims 1-11.
14. A storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it causes the computer to perform the method as described in any one of claims 1 to 11.
15. A computer program product, comprising a computer program, characterized in that, When the computer program is run, it causes the motor controller to perform the method as described in any one of claims 1 to 11.