A motor rotor initial angle identification method and device and a storage medium

Abstract

The application discloses a motor rotor initial angle identification method and device and a storage medium. The motor rotor initial angle identification method sequentially applies first vector voltage V1, second vector voltage V2 and third vector voltage V3 to a stator, and calculates first induced current I1, second induced current I2 and third induced current I3 according to the first vector voltage V1, the second vector voltage V2 and the third vector voltage V3. The included angle between the first vector voltage direction and the second vector voltage direction, the included angle between the second vector voltage direction and the third vector voltage direction, and the included angle between the first vector voltage direction and the third vector voltage direction are all 120 degrees, thereby avoiding the phenomenon that the starting position of the rotor falls in the blind area of the applied vector current or the position of the rotor deviates 180 degrees from the vector direction of the applied current, leading to the failure of positioning the rotor, the steps are simple, and the positioning precision is high.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a method, device and storage medium for identifying the initial angle of a motor rotor. Background Technology

[0002] Permanent magnet servo drive systems typically employ vector control. Vector control utilizes the transformation from a stationary coordinate system to a rotating coordinate system to decouple the excitation and torque components of the stator current, allowing the permanent magnet synchronous motor (PMSM) to independently control flux and torque, much like a DC motor. Accurate rotor position detection is a necessary condition for vector control decoupling. Only with accurate rotor position knowledge can the PMSM be represented as an equivalent model in the dq coordinate system according to the requirements of vector coordinate transformation. If the rotor position detection is accurate and without deviation, the magnetomotive force generated by the stator current vector will be at a 90° angle to the rotor magnetomotive force. At this point, the interaction force between the two is maximized, meaning the stator current vector is fully utilized. If the rotor position detection is inaccurate or has a large deviation, the interaction force between the two magnetomotive forces may be insufficient or even have a force direction opposite to the preset value, leading to start-up failure.

[0003] Therefore, in response to this situation, existing methods for identifying the initial angle of the motor rotor usually involve passing a static current through one winding of the motor stator. However, since the initial position of the rotor is random, when the applied positioning current vector makes a small angle with the rotor position, the positioning torque will be insufficient to overcome the magnetic reluctance torque and will not be able to make the rotor rotate for positioning. If the rotor's initial position is near the direction of the vector current or deviates from the direction of the vector current by 180°, the rotor cannot be identified for positioning. Increasing the positioning current can reduce the probability of the rotor falling into the positioning blind zone, but it still cannot guarantee successful positioning every time, resulting in low positioning accuracy. Summary of the Invention

[0004] The purpose of this invention is to provide a method, device and storage medium for identifying the initial angle of a motor rotor, so as to solve the problem that the rotor cannot be identified and positioned when the rotor's initial position is near the direction of the vector current or deviates from the direction of the vector current by 180°, resulting in low positioning accuracy.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A method for identifying the initial angle of a motor rotor, comprising:

[0007] A first vector voltage V1 is applied to the stator based on a first set voltage amplitude and a first vector voltage direction, and a first induced current I1 is calculated based on the first vector voltage V1.

[0008] A second vector voltage V2 is applied to the stator based on the second set voltage amplitude and the second vector voltage direction, and a second induced current I2 is calculated based on the second vector voltage V2;

[0009] A third vector voltage V3 is applied to the stator based on the third set voltage amplitude and the third vector voltage direction, and a third induced current I3 is calculated based on the third vector voltage V3;

[0010] The rotor is pre-positioned based on the first induced current I1, the second induced current I2, and the third induced current I3;

[0011] Wherein, the first vector voltage direction, the second vector voltage direction and the third vector voltage direction are coplanar, and the angle between the first vector voltage direction and the second vector voltage direction is 120°, the angle between the second vector voltage direction and the third vector voltage direction is 120°, and the angle between the first vector voltage direction and the third vector voltage direction is 120°.

[0012] Preferably, the specific steps for pre-positioning the rotor based on the first induced current I1, the second induced current I2, and the third induced current I3 include:

[0013] Compare the magnitudes of the first induced current I1, the second induced current I2, and the third induced current I3.

[0014] The rotor is positioned for the first time based on the minimum current amplitude of the first induced current I1, the second induced current I2, and the third induced current I3. Then, the rotor is positioned for the second time based on the maximum current amplitude of the first induced current I1, the second induced current I2, and the third induced current I3, so as to achieve pre-positioning.

[0015] Preferably, the magnitudes of the first set voltage amplitude, the second set voltage amplitude, and the third set voltage amplitude are all equal.

[0016] Preferably, the first set voltage amplitude is greater than or equal to the minimum voltage amplitude that can make the rotor rotate, the second set voltage amplitude is greater than or equal to the minimum voltage amplitude that can make the rotor rotate, and the third set voltage amplitude is greater than or equal to the minimum voltage amplitude that can make the rotor rotate.

[0017] Preferably, the duration of applying the first vector voltage V1, the duration of applying the second vector voltage V2, and the duration of applying the third vector voltage V3 are all equal.

[0018] Preferably, the rotor is pre-positioned based on the first induced current I1, the second induced current I2, and the third induced current I3, and then the following steps are included:

[0019] Based on the smaller of the current amplitudes of the first induced current I1, the second induced current I2, and the third induced current I3, the fourth vector voltage V4 and the fifth vector voltage V5 with a fourth set voltage amplitude are applied to the stator in sequence according to the two corresponding vector voltage directions, and the fourth induced current I4 and the fifth induced current I5 are calculated.

[0020] The rotor is finally positioned based on the current amplitude of the fourth induced current I4 and the current amplitude of the fifth induced current I5.

[0021] Preferably, the specific steps for final positioning of the rotor based on the current amplitude of the fourth induced current I4 and the current amplitude of the fifth induced current I5 include:

[0022] Compare the magnitudes of the fourth induced current I4 and the fifth induced current I5.

[0023] The rotor is finally positioned based on the larger of the current amplitude of the fourth induced current I4 and the current amplitude of the fifth induced current I5.

[0024] Preferably, the fourth set voltage amplitude is greater than any one of the first set voltage amplitude, the second set voltage amplitude, and the third set voltage amplitude.

[0025] A motor rotor initial angle identification device includes a processor and a memory. The memory stores computer-readable instructions. When the computer reads the instructions and the processor executes them, the above-described motor rotor initial angle identification method is run.

[0026] A storage medium storing a computer program that, when executed by a processor, runs the aforementioned method for identifying the initial angle of a motor rotor.

[0027] The beneficial effects of this invention are:

[0028] The present invention aims to provide a method, apparatus, and storage medium for identifying the initial angle of a motor rotor. The method involves applying a first vector voltage V1 to the stator based on a first set voltage amplitude and a first vector voltage direction, and calculating a first induced current I1 based on the first vector voltage V1; applying a second vector voltage V2 to the stator based on a second set voltage amplitude and a second vector voltage direction, and calculating a second induced current I2 based on the second vector voltage V2; and applying a third vector voltage V3 to the stator based on a third set voltage amplitude and a third vector voltage direction, and calculating a third induced current I3 based on the third vector voltage V3. The first, second, and third vector voltage directions are coplanar, and the angle between the first and second vector voltage directions is 120°, the angle between the second and third vector voltage directions is 120°, and the angle between the first and third vector voltage directions is 120°. This is achieved by sequentially applying the first vector voltage V1, the second vector voltage V2, and the third vector voltage V3 to the stator. Regarding V2 and the third vector voltage V3, it is understood that even if the angle between the vector voltage direction of one of the first vector voltages V1, the second vector voltage V2, and the third vector voltage V3 and the initial position of the rotor is very small, or if the deviation from the vector voltage direction by 180° results in the inability to generate an induced current, the other two of the first vector voltages V1, the second vector voltage V2, and the third vector voltage V3 must be relatively large with respect to the initial position of the rotor. Therefore, applying the other two of the first vector voltages V1, the second vector voltage V2, and the third vector voltage V3 will inevitably generate an induced current. Thus, the rotor can be pre-positioned directly based on the first induced current I1, the second induced current I2, and the third induced current I3. This effectively avoids the phenomenon in the prior art where the rotor's initial position falls within the blind zone of the applied vector current or the rotor's position deviates from the vector direction of the applied vector current by 180°, resulting in the inability to position the rotor. The process is simple and the positioning accuracy is high. Attached Figure Description

[0029] Figure 1 This is a flowchart of a method for identifying the initial angle of a motor rotor provided in a specific embodiment of the present invention;

[0030] Figure 2 This is a principle description of the motor rotor initial angle identification method provided by a specific example of the present invention. Figure 1 ;

[0031] Figure 3 This is a principle description of the motor rotor initial angle identification method provided by a specific example of the present invention. Figure 2 ;

[0032] Figure 4 This is a schematic diagram of a motor rotor initial angle identification device provided in a specific embodiment of the present invention.

[0033] In the picture:

[0034] 1. Processor; 2. Memory; 3. Bus. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0036] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0039] Existing methods for identifying the initial angle of a motor rotor typically involve applying a static current to one winding of the motor stator. However, since the initial position of the rotor is random, when the applied positioning current vector forms a small angle with the rotor position, the positioning torque will be insufficient to overcome the magnetic reluctance torque, making it impossible to rotate the rotor for positioning. If the rotor's initial position is near the direction of the vector current or deviates from the direction of the vector current by 180°, the rotor cannot be identified for positioning. Increasing the positioning current can reduce the probability of the rotor falling into the positioning blind zone, but it still cannot guarantee successful positioning every time, resulting in low positioning accuracy.

[0040] Therefore, in view of this situation, the present invention provides a method for identifying the initial angle of a motor rotor. This method can effectively avoid the phenomenon in the prior art where the starting position of the rotor falls in the blind zone of the applied vector current or the position of the rotor deviates from the vector direction of the applied current by 180°, which leads to the inability to locate the rotor. The method is simple and has high positioning accuracy.

[0041] Specifically, such as Figure 1 As shown, the method for identifying the initial angle of the motor rotor includes the following steps:

[0042] S100. Apply a first vector voltage V1 to the stator according to the first set voltage amplitude and the first vector voltage direction, and calculate the first induced current I1 according to the first vector voltage V1.

[0043] It is understandable that the direction of the first vector voltage can be arbitrary.

[0044] S200: Apply a second vector voltage V2 to the stator according to the second set voltage amplitude and the second vector voltage direction, and calculate the second induced current I2 according to the second vector voltage V2.

[0045] S300. Apply a third vector voltage V3 to the stator based on the third set voltage amplitude and the third vector voltage direction, and calculate the third induced current I3 based on the third vector voltage V3.

[0046] The first, second, and third vector voltage directions are coplanar, and the angle between the first and second vector voltage directions is 120°, the angle between the second and third vector voltage directions is 120°, and the angle between the first and third vector voltage directions is 120°.

[0047] It is understandable that, with the first vector voltage direction as the reference direction, the second and third vector voltage directions are subsequently determined.

[0048] The specific calculation methods for calculating the first induced current I1 based on the first vector voltage V1, the second induced current I2 based on the second vector voltage V2, and the third induced current I3 based on the third vector voltage V3 are existing technologies and will not be elaborated here.

[0049] Steps S100 to S300 are not performed in any particular order. In this embodiment, steps S100 to S300 are performed sequentially.

[0050] S400, the rotor is pre-positioned based on the first induced current I1, the second induced current I2 and the third induced current I3.

[0051] Specifically, pre-positioning the rotor based on the first induced current I1, the second induced current I2, and the third induced current I3 includes the following steps:

[0052] S410. Compare the magnitudes of the first induced current I1, the second induced current I2, and the third induced current I3.

[0053] S420. The rotor is positioned for the first time based on the minimum current amplitude of the first induced current I1, the second induced current I2, and the third induced current I3. Then, the rotor is positioned for the second time based on the maximum current amplitude of the first induced current I1, the second induced current I2, and the third induced current I3, so as to achieve pre-positioning.

[0054] Specifically, the direction of the first vector voltage is the same as the direction of the first induced current I1; the direction of the second vector voltage is the same as the direction of the second induced current I2; and the direction of the third vector voltage is the same as the direction of the third induced current I3.

[0055] In this embodiment, as Figure 2As shown, the plane containing the first vector voltage direction, the second vector voltage direction, and the third vector voltage direction is divided into regions A1, A2, B1, B2, C1, and C2. For example, taking the case where the amplitude of the first induced current I1 is greater than the amplitude of the second induced current I2, and the amplitude of the second induced current I2 is greater than the amplitude of the third induced current I3, based on the rule that the smaller the amplitude of the induced current, the smaller the angle between the rotor and the vector current direction of the induced current, the rotor is first positioned using the third induced current I3 to determine whether the rotor is in region C1 or C2. Based on the rule that the larger the amplitude of the induced current, the larger the angle between the rotor and the vector current direction of the induced current, the rotor is positioned a second time using the first induced current I1 to determine whether the rotor is in region C1. In this way, the rotor can be pre-positioned directly, and the phenomenon that the rotor's starting position falls in the blind zone of the applied vector current or the rotor's position deviates from the vector direction of the applied vector current by 180°, which leads to the inability to position the rotor, is not found in the prior art. The steps are simple and the positioning accuracy is high.

[0056] Preferably, the magnitudes of the first set voltage amplitude, the second set voltage amplitude, and the third set voltage amplitude are all equal. This setting ensures the effectiveness and accuracy of steps S410 and S420, where the rotor is first positioned using the smallest of the current amplitudes of the first induced current I1, the second induced current I2, and the third induced current I3, and then a second positioning is performed using the largest of these three current amplitudes.

[0057] Preferably, the durations for applying the first vector voltage V1, the second vector voltage V2, and the third vector voltage V3 are all equal. This configuration further ensures the effectiveness and accuracy of the first positioning of the rotor using the minimum of the current amplitudes of the first induced current I1, the second induced current I2, and the third induced current I3, followed by the second positioning using the maximum of these three current amplitudes.

[0058] Preferably, the first set voltage amplitude is greater than or equal to the minimum voltage amplitude that allows the rotor to rotate, the second set voltage amplitude is greater than or equal to the minimum voltage amplitude that allows the rotor to rotate, and the third set voltage amplitude is greater than or equal to the minimum voltage amplitude that allows the rotor to rotate. This configuration ensures that when the first vector voltage V1, the second vector voltage V2, and the third vector voltage V3 are sequentially applied to the stator, the rotor will exhibit at least two micro-rotations, thereby facilitating pre-positioning of the motor rotor using the first vector voltage V1, the second vector voltage V2, and the third vector voltage V3.

[0059] Specifically, taking the application of a third vector voltage V3, where the angle between the direction of the third vector voltage and the rotor is very small or deviates from the direction of the vector voltage by 180° as an example, since the angle between the direction of the third vector voltage and the initial position of the rotor is very small or deviates from the direction of the vector voltage by 180°, it can be understood that even if the amplitude of the third set voltage is greater than or equal to the minimum voltage amplitude that can make the rotor rotate, the motor rotor will not rotate, and thus the value of the third induced current I3 is almost zero. When the first vector voltage V1 and the second vector voltage V2 are applied in sequence, since the angles between the directions of the first and second vector voltages and the initial position of the rotor are relatively large, the rotor can rotate slightly when the first vector voltage V1 and the second vector voltage V2 are applied, and corresponding first induced current I1 and second induced current I2 are generated. Thus, by comparing the first induced current I1 generated by applying the first vector voltage V1, the second induced current I2 generated by applying the second vector voltage V2, and the third induced current I3 generated by applying the third vector voltage V3, the motor rotor is pre-positioned. It is understandable that when the initial position of the rotor is large with respect to the first vector voltage direction of the first vector voltage V1, the second vector voltage direction of the second vector voltage V2, and the first vector voltage direction of the third vector voltage V3, the rotor can rotate slightly when the first vector voltage V1, the second vector voltage V2, and the third vector voltage V3 are applied, generating corresponding first induced current I1, second induced current I2, and third induced current I3. Thus, the motor rotor is pre-positioned by comparing the first induced current I1 generated by the first vector voltage V1, the second induced current I2 generated by the second vector voltage V2, and the third induced current I3 generated by the third vector voltage V3.

[0060] To further refine the rotor position, the initial rotor angle identification method for this motor includes the following steps after step S420:

[0061] S500: Based on the smaller of the current amplitudes of the first induced current I1, the second induced current I2, and the third induced current I3, the fourth vector voltage V4 and the fifth vector voltage V5 with the amplitude of the fourth set voltage are applied to the stator in sequence, and the fourth induced current I4 and the fifth induced current I5 are calculated.

[0062] The specific calculation methods for calculating the fourth induced current I4 based on the fourth vector voltage V4 and the fifth induced current I5 based on the fifth vector voltage V5 are existing technologies and will not be elaborated here.

[0063] S600. The rotor is finally positioned based on the current amplitude of the fourth induced current I4 and the current amplitude of the fifth induced current I5.

[0064] In this embodiment, taking, for example, the amplitude of the first induced current I1 being greater than the amplitude of the second induced current I2, and the amplitude of the second induced current I2 being greater than the amplitude of the third induced current I3, a fourth vector voltage V4 with an amplitude of a fourth set voltage is applied to the stator according to the second vector voltage direction to obtain a fourth induced current I4. Then, a fifth vector voltage V5 with an amplitude of a fourth set voltage is applied to the stator according to the third vector voltage direction to obtain a fifth induced current I5. Finally, the rotor is positioned according to the amplitudes of the fourth induced current I4 and the fifth induced current I5.

[0065] Specifically, the steps for performing the second positioning of the rotor based on the current amplitudes of the fourth induced current I4 and the fifth induced current I5 include:

[0066] S610. Compare the magnitudes of the fourth induced current I4 and the fifth induced current I5.

[0067] S620. The rotor is positioned a second time based on the larger of the current amplitude of the fourth induced current I4 and the current amplitude of the fifth induced current I5.

[0068] In this embodiment, as Figure 2 and Figure 3As shown, region A1 is divided into regions A11 and A12, region A2 into regions A21 and A22, region B1 into regions B11 and B12, region B2 into regions B21 and B22, region C1 into regions C11 and C12, and region C2 into regions C21 and C22. For example, taking the case where the amplitude of the fourth induced current I4 is greater than that of the fifth induced current I5, based on the principle that the smaller the amplitude of the induced current, the smaller the angle between the rotor and the vector current direction of the induced current, and vice versa, the rotor region C11 can be determined, thus achieving precise rotor positioning.

[0069] Preferably, the fourth set voltage amplitude is greater than any one of the first set voltage amplitude, the second set voltage amplitude, and the third set voltage amplitude. This setting further improves the positioning accuracy of the positioning rotor.

[0070] The present invention also provides a device for identifying the initial angle of a motor rotor, such as... Figure 4 As shown, it includes a processor 1 and a memory 2. The processor 1 stores computer-readable instructions. When the computer reads the readable instructions and the processor 1 executes them, the above-described method for identifying the initial angle of the motor rotor is run. Specifically, the processor 1 and the memory 2 are interconnected and communicate with each other via a communication bus 3 and / or other forms of connection mechanism (not shown). The memory 2 stores a computer program executable by the processor 1. When the computing device is running, the processor 1 executes the computer program to perform the method in any of the optional implementations of the above embodiments.

[0071] The present invention also provides a storage medium in which a computer program, when executed by a processor 1, performs the method of the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0072] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for identifying the initial angle of a motor rotor, characterized in that, include: A first vector voltage V1 is applied to the stator based on a first set voltage amplitude and a first vector voltage direction, and a first induced current I1 is calculated based on the first vector voltage V1. A second vector voltage V2 is applied to the stator based on the second set voltage amplitude and the second vector voltage direction, and a second induced current I2 is calculated based on the second vector voltage V2; A third vector voltage V3 is applied to the stator based on the third set voltage amplitude and the third vector voltage direction, and a third induced current I3 is calculated based on the third vector voltage V3; The rotor is pre-positioned based on the first induced current I1, the second induced current I2, and the third induced current I3; Wherein, the first vector voltage direction, the second vector voltage direction and the third vector voltage direction are coplanar, and the angle between the first vector voltage direction and the second vector voltage direction is 120°, the angle between the second vector voltage direction and the third vector voltage direction is 120°, and the angle between the first vector voltage direction and the third vector voltage direction is 120°; The specific steps for pre-positioning the rotor based on the first induced current I1, the second induced current I2, and the third induced current I3 include: Compare the magnitudes of the first induced current I1, the second induced current I2, and the third induced current I3. The rotor is positioned for the first time based on the minimum current amplitude of the first induced current I1, the second induced current I2, and the third induced current I3. Then, the rotor is positioned for the second time based on the maximum current amplitude of the first induced current I1, the second induced current I2, and the third induced current I3, so as to achieve pre-positioning.

2. The method for identifying the initial angle of a motor rotor according to claim 1, characterized in that, The magnitudes of the first set voltage amplitude, the second set voltage amplitude, and the third set voltage amplitude are all equal.

3. The method for identifying the initial angle of a motor rotor according to claim 1, characterized in that, The first set voltage amplitude is greater than or equal to the minimum voltage amplitude that can make the rotor rotate, the second set voltage amplitude is greater than or equal to the minimum voltage amplitude that can make the rotor rotate, and the third set voltage amplitude is greater than or equal to the minimum voltage amplitude that can make the rotor rotate.

4. The method for identifying the initial angle of a motor rotor according to claim 1, characterized in that, The duration of applying the first vector voltage V1, the duration of applying the second vector voltage V2, and the duration of applying the third vector voltage V3 are all equal.

5. The method for identifying the initial angle of a motor rotor according to any one of claims 1-4, characterized in that, The rotor is pre-positioned based on the first induced current I1, the second induced current I2, and the third induced current I3, and the process further includes the following steps: Based on the smaller of the current amplitudes of the first induced current I1, the second induced current I2, and the third induced current I3, the fourth vector voltage V4 and the fifth vector voltage V5 with a fourth set voltage amplitude are applied to the stator in sequence according to the two corresponding vector voltage directions, and the fourth induced current I4 and the fifth induced current I5 are calculated. The rotor is finally positioned based on the current amplitude of the fourth induced current I4 and the current amplitude of the fifth induced current I5.

6. The method for identifying the initial angle of a motor rotor according to claim 5, characterized in that, The specific steps for final positioning of the rotor based on the current amplitude of the fourth induced current I4 and the current amplitude of the fifth induced current I5 include: Compare the magnitudes of the fourth induced current I4 and the fifth induced current I5. The rotor is finally positioned based on the larger of the current amplitude of the fourth induced current I4 and the current amplitude of the fifth induced current I5.

7. The method for identifying the initial angle of a motor rotor according to claim 5, characterized in that, The fourth set voltage amplitude is greater than any one of the first set voltage amplitude, the second set voltage amplitude, and the third set voltage amplitude.

8. A device for identifying the initial angle of a motor rotor, characterized in that, It includes a processor (1) and a memory (2), wherein the memory (2) stores computer-readable instructions, and when the computer-readable instructions are executed by the processor (1), the method for identifying the initial angle of the motor rotor as described in any one of claims 1-7 is executed.

9. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor (1), it runs the method for identifying the initial angle of the motor rotor as described in any one of claims 1-7.

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