Harmonic injection methods, devices, motors, automobiles, and dielectrics for permanent magnet synchronous motors

Abstract

This application discloses a harmonic injection method, apparatus, motor, vehicle, and medium for a permanent magnet synchronous motor, belonging to the field of motor control. It includes: determining a first angle and a second angle for the 5th and 7th harmonics of the permanent magnet synchronous motor; converting the first and second angles into radians to obtain a third angle and a fourth angle; based on the third and fourth angles, determining the voltages of the 5th harmonic on the d-axis and q-axis, and obtaining the voltages of the 7th harmonic on the d-axis and q-axis, respectively; determining the harmonic voltage on the d-axis based on the voltages of the 5th and 7th harmonics on the d-axis; determining the harmonic voltage on the q-axis based on the voltages of the 5th and 7th harmonics on the q-axis; and injecting the 5th and 7th harmonics into the permanent magnet synchronous motor based on the harmonic voltages on the d-axis and q-axis. This application can improve the harmonic injection effect of permanent magnet synchronous motors.

Description

Technical Field

[0001] This application relates to the field of motor control, and in particular to a harmonic injection method, device, motor, automobile, and medium for a permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in various fields due to their high operating efficiency and stable overall performance, such as the automotive industry. However, due to the motor itself or its inverter, PSMs introduce current harmonics. Furthermore, the stator windings of automotive PSMs are Y-connected and symmetrically distributed. Their physical structure ensures that the back EMF waveform is always half-wave symmetrical, thus preventing even-order harmonics and harmonics that are multiples of 3. Consequently, the current harmonics introduced by automotive PSMs are primarily the 5th and 7th orders. Since these current harmonics reduce the efficiency and overall performance of PSMs, harmonic injection is necessary to eliminate the 5th and 7th current harmonics. Summary of the Invention

[0003] This application provides a harmonic injection method, apparatus, motor, vehicle, and dielectric for a permanent magnet synchronous motor, which can improve the harmonic injection effect of the permanent magnet synchronous motor. The technical solution is as follows:

[0004] On the one hand, a harmonic injection method for a permanent magnet synchronous motor is provided, the method comprising:

[0005] The first angle of the 5th harmonic and the second angle of the 7th harmonic of the permanent magnet synchronous motor are determined, wherein the first angle of the 5th harmonic and the second angle of the 7th harmonic are both in angle system.

[0006] The first angle of the 5th harmonic and the second angle of the 7th harmonic are converted from degrees to radians to obtain the third angle of the 5th harmonic and the fourth angle of the 7th harmonic.

[0007] Determine the harmonic voltage of the 5th harmonic and the harmonic voltage of the 7th harmonic;

[0008] Based on the third angle, the harmonic voltage of the 5th harmonic is converted into the dq axis rotation coordinate of the permanent magnet synchronous motor to obtain the voltage of the 5th harmonic on the d axis and the voltage on the q axis respectively;

[0009] Based on the fourth angle, the harmonic voltage of the 7th harmonic is converted into the dq rotating coordinate system of the permanent magnet synchronous motor to obtain the voltage of the 7th harmonic on the d-axis and the voltage on the q-axis, respectively.

[0010] Based on the voltage of the 5th harmonic on the d-axis and the voltage of the 7th harmonic on the d-axis, the harmonic voltage on the d-axis is determined.

[0011] Based on the voltage of the 5th harmonic on the q-axis and the voltage of the 7th harmonic on the q-axis, determine the harmonic voltage on the q-axis;

[0012] Based on the harmonic voltage of the d-axis and the harmonic voltage of the q-axis, the permanent magnet synchronous motor is injected with the 5th and 7th harmonics.

[0013] In one possible implementation, the injection of 5th and 7th harmonics into the permanent magnet synchronous motor based on the harmonic voltages of the d-axis and the q-axis includes:

[0014] Determine the operating conditions of the permanent magnet synchronous motor;

[0015] Based on the operating conditions, determine the maximum motor speed, minimum motor speed, and motor speed difference of the permanent magnet synchronous motor under the operating conditions for harmonic injection.

[0016] Determine the current permanent magnet synchronous motor speed;

[0017] Based on the maximum motor speed, the minimum motor speed, the motor speed difference, and the current permanent magnet synchronous motor speed, determine whether the permanent magnet synchronous motor satisfies the harmonic injection algorithm enable;

[0018] When the permanent magnet synchronous motor satisfies the harmonic injection algorithm enable condition, the harmonic voltages of the d-axis and the q-axis are gradient-limited, and the gradient-limited harmonic voltages of the d-axis and the q-axis are output, so that the gradient-limited harmonic voltages of the d-axis and the q-axis eliminate the current harmonics of the 5th and 7th harmonics.

[0019] In another possible implementation, determining whether the permanent magnet synchronous motor satisfies the harmonic injection algorithm enable condition based on the maximum motor speed, the minimum motor speed, the motor speed difference, and the current permanent magnet synchronous motor speed includes:

[0020] The first motor speed is obtained by determining the difference between the maximum motor speed and the difference between the motor speeds;

[0021] The second motor speed is obtained by summing the difference between the minimum motor speed and the motor speed.

[0022] If the current rotational speed is not less than the rotational speed of the first motor and not greater than the rotational speed of the second motor, then the permanent magnet synchronous motor is determined to satisfy the harmonic injection algorithm enable.

[0023] In another possible implementation, determining the first angle of the 5th harmonic and the second angle of the 7th harmonic of the permanent magnet synchronous motor includes:

[0024] With the dq axis rotation coordinate system of the permanent magnet synchronous motor as a reference, the fundamental magnetic flux of the permanent magnet synchronous motor rotates counterclockwise at a speed of ω;

[0025] When the 5th harmonic rotates clockwise at a speed of 5ω, the clockwise rotation angle of the 5th harmonic relative to the dq axis rotation coordinate system is determined; and when the 7th harmonic rotates at a speed of 7ω, the counterclockwise rotation angle of the 7th harmonic relative to the dq axis rotation coordinate system is determined.

[0026] Based on the clockwise rotation angle, the initial phase of the 5th harmonic, and the first compensation angle, the first angle of the 5th harmonic is determined;

[0027] The second angle of the 7th harmonic is determined based on the counterclockwise rotation angle, the initial phase of the 7th harmonic, and the second compensation angle.

[0028] In another possible implementation, the step of converting the harmonic voltage of the 5th harmonic based on the third angle into the dq-axis rotational coordinates of the permanent magnet synchronous motor to obtain the voltages of the 5th harmonic on the d-axis and q-axis, respectively, includes:

[0029] Based on the aforementioned third angle, the harmonic voltage of the 5th harmonic is converted into the dq-axis rotational coordinates of the permanent magnet synchronous motor using the following formula, yielding the voltages of the 5th harmonic on the d-axis and q-axis respectively:

[0030] Formula 1: U d_P =U P cos(θ1)-U P sin(θ1)

[0031] U q_P =U P sin(θ1)+U P cos(θ1)

[0032] Among them, U d_P U is the voltage of the 5th harmonic on the d-axis. q_P The voltage of the 5th harmonic on the q-axis is θ; θ1 is the third angle, U P The harmonic voltage of the 5th harmonic;

[0033] Based on the fourth angle, the harmonic voltage of the 7th harmonic is converted into the dq rotating coordinate system of the permanent magnet synchronous motor to obtain the voltages of the 7th harmonic on the d-axis and q-axis, respectively, including:

[0034] Based on the aforementioned fourth angle, the harmonic voltage of the 7th harmonic is converted into the dq-axis rotational coordinates of the permanent magnet synchronous motor using the following formula two, yielding the voltages of the 7th harmonic on the d-axis and q-axis respectively:

[0035] Formula 2: U d_N =U N cos(θ2)-U N sin(θ2)

[0036] U q_N =U N sin(θ2)+U N cos(θ2)

[0037] Among them, U d_N U is the voltage of the 7th harmonic on the d-axis. q_N θ2 is the voltage of the 7th harmonic on the q-axis; θ2 is the fourth angle, U N The harmonic voltage of the 7th harmonic is given.

[0038] On the other hand, a harmonic injection device for a permanent magnet synchronous motor is provided, the device comprising:

[0039] The first determining module is used to determine the first angle of the 5th harmonic and the second angle of the 7th harmonic of the permanent magnet synchronous motor, wherein the first angle of the 5th harmonic and the second angle of the 7th harmonic are both in angle system.

[0040] The first conversion module is used to convert the first angle of the 5th harmonic and the second angle of the 7th harmonic from degrees to radians to obtain the third angle of the 5th harmonic and the fourth angle of the 7th harmonic.

[0041] The second determining module is used to determine the harmonic voltage of the 5th harmonic and the harmonic voltage of the 7th harmonic;

[0042] The second conversion module is used to convert the harmonic voltage of the 5th harmonic into the dq axis rotation coordinate of the permanent magnet synchronous motor based on the third angle, so as to obtain the voltage of the 5th harmonic on the d axis and the voltage on the q axis respectively.

[0043] The third conversion module is used to convert the harmonic voltage of the 7th harmonic into the dq rotating coordinate system of the permanent magnet synchronous motor based on the fourth angle, so as to obtain the voltage of the 7th harmonic on the d-axis and the voltage on the q-axis respectively.

[0044] The third determining module is used to determine the harmonic voltage on the d-axis based on the voltage of the 5th harmonic on the d-axis and the voltage of the 7th harmonic on the d-axis.

[0045] The fourth determining module is used to determine the harmonic voltage on the q-axis based on the voltage of the 5th harmonic on the q-axis and the voltage of the 7th harmonic on the q-axis.

[0046] The injection module is used to inject the 5th and 7th harmonics into the permanent magnet synchronous motor based on the harmonic voltage of the d-axis and the harmonic voltage of the q-axis.

[0047] In one possible implementation, the injection module is configured to: determine the operating condition of the permanent magnet synchronous motor; based on the operating condition, determine the maximum motor speed, minimum motor speed, and motor speed difference of the permanent magnet synchronous motor under the operating condition for harmonic injection; determine the current speed of the permanent magnet synchronous motor; based on the maximum motor speed, the minimum motor speed, the motor speed difference, and the current speed of the permanent magnet synchronous motor, determine whether the permanent magnet synchronous motor satisfies the harmonic injection algorithm enabling condition; if the permanent magnet synchronous motor satisfies the harmonic injection algorithm enabling condition, perform gradient limiting on the harmonic voltages of the d-axis and the q-axis, and output the gradient-limited harmonic voltages of the d-axis and the q-axis, such that the gradient-limited harmonic voltages of the d-axis and the q-axis eliminate the 5th harmonic current harmonic and the 7th harmonic current harmonic.

[0048] In another possible implementation, the injection module is used to determine the difference between the maximum motor speed and the difference between the motor speeds to obtain a first motor speed; determine the sum of the minimum motor speed and the difference between the motor speeds to obtain a second motor speed; and determine that the permanent magnet synchronous motor satisfies the harmonic injection algorithm enable condition when the current speed is not less than the first motor speed and the current speed is not greater than the second motor speed.

[0049] In another possible implementation, the first determining module is configured to: use the dq-axis rotational coordinate system of the permanent magnet synchronous motor as a reference, with the fundamental flux linkage of the permanent magnet synchronous motor rotating counterclockwise at a speed of ω; determine the clockwise rotation angle of the 5th harmonic relative to the dq-axis rotational coordinate system when the 5th harmonic rotates clockwise at a speed of 5ω; and determine the counterclockwise rotation angle of the 7th harmonic relative to the dq-axis rotational coordinate system when the 7th harmonic rotates at a speed of 7ω; determine a first angle of the 5th harmonic based on the clockwise rotation angle, the initial phase of the 5th harmonic, and a first compensation angle; and determine a second angle of the 7th harmonic based on the counterclockwise rotation angle, the initial phase of the 7th harmonic, and a second compensation angle.

[0050] In another possible implementation, the second conversion module is used to convert the fifth harmonic voltage into the dq-axis rotational coordinates of the permanent magnet synchronous motor based on the third angle using the following formula: to obtain the voltages of the fifth harmonic on the d-axis and q-axis respectively.

[0051] Formula 1: U d_P =U P cos(θ1)-U P sin(θ1)

[0052] U q_P =U P sin(θ1)+U P cos(θ1)

[0053] Among them, U d_P U is the voltage of the 5th harmonic on the d-axis. q_P The voltage of the 5th harmonic on the q-axis is θ; θ1 is the third angle, U P The harmonic voltage of the 5th harmonic;

[0054] The third conversion module is used to convert the harmonic voltage of the 7th harmonic into the dq-axis rotational coordinates of the permanent magnet synchronous motor based on the fourth angle using the following formula two, to obtain the voltages of the 7th harmonic on the d-axis and q-axis respectively:

[0055] Formula 2: U d_N =U N cos(θ2)-U N sin(θ2)

[0056] U q_N =U N sin(θ2)+U N cos(θ2)

[0057] Among them, U d_N U is the voltage of the 7th harmonic on the d-axis. q_N θ2 is the voltage of the 7th harmonic on the q-axis; θ2 is the fourth angle, U N The harmonic voltage of the 7th harmonic is given.

[0058] On the other hand, a permanent magnet synchronous motor is provided, which includes a processor and a memory. The memory stores at least one piece of program code, which is loaded and executed by the processor to implement the harmonic injection method of the permanent magnet synchronous motor described above.

[0059] On the other hand, a new energy vehicle is provided, which includes the aforementioned permanent magnet synchronous motor.

[0060] On the other hand, a computer-readable storage medium is provided, wherein at least one piece of program code is stored in the storage medium, the at least one piece of program code being loaded and executed by a processor to implement the above-described harmonic injection method for a permanent magnet synchronous motor.

[0061] On the other hand, a computer program product is provided, the product storing at least one piece of program code, the at least one piece of program code being executed by a processor to implement the above-described harmonic injection method for a permanent magnet synchronous motor.

[0062] In the embodiments of this application, when determining the harmonic voltages of the 5th harmonic on the d-axis and q-axis, and when determining the harmonic voltages of the 7th harmonic on the d-axis and q-axis, the current angle of the permanent magnet synchronous motor is taken into consideration. Since the current angle of the permanent magnet synchronous motor is closely related to its rotational speed, this application can adjust the harmonic injection situation in a timely manner when the rotational speed of the permanent magnet synchronous motor changes, thereby realizing harmonic injection based on the operating conditions (rotational speed) of the permanent magnet synchronous motor, thus improving the harmonic injection effect of the permanent magnet synchronous motor.

[0063] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this disclosure. Attached Figure Description

[0064] Figure 1 This is a flowchart illustrating a harmonic injection method for a permanent magnet synchronous motor, as shown in an exemplary embodiment of this application;

[0065] Figure 2 This is a schematic diagram illustrating the determination of a first angle and a third angle, as shown in an exemplary embodiment of this application;

[0066] Figure 3 This is a flowchart illustrating a harmonic injection method for a permanent magnet synchronous motor, as shown in an exemplary embodiment of this application;

[0067] Figure 4 This is a flowchart illustrating a harmonic injection method for a permanent magnet synchronous motor, as shown in an exemplary embodiment of this application;

[0068] Figure 5 This is a schematic diagram illustrating whether the harmonic injection algorithm is enabled, as shown in an exemplary embodiment of this application.

[0069] Figure 6 This is a block diagram illustrating a harmonic injection device for a permanent magnet synchronous motor, as shown in an exemplary embodiment of this application.

[0070] Figure 7 This is a block diagram illustrating a permanent magnet synchronous motor in an exemplary embodiment of this application. Detailed Implementation

[0071] To make the technical solution and advantages of this application clearer, the embodiments of this application will be described in further detail below.

[0072] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0073] It should be noted that all information (including but not limited to user equipment information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.), and signals involved in this application have been authorized by the user or fully authorized by all parties, and the collection, use, and processing of related data must comply with the relevant laws, regulations, and standards of the relevant countries and regions. For example, the first angle, second angle, and harmonic voltage involved in this application were obtained with full authorization.

[0074] Please refer to Figure 1 This document illustrates a flowchart of a harmonic injection method for a permanent magnet synchronous motor, as shown in an exemplary embodiment of this application. (Reference) Figure 1 The method includes:

[0075] Step 101: Determine the first angle of the 5th harmonic and the second angle of the 7th harmonic of the permanent magnet synchronous motor. Both the first angle of the 5th harmonic and the second angle of the 7th harmonic are in degrees.

[0076] The stator windings of automotive permanent magnet synchronous motors (PMSMs) are Y-connected and symmetrically distributed. Their physical structure ensures that the back EMF waveform is always half-wave symmetrical, thus preventing even-order harmonics and harmonics that are multiples of 3. Consequently, the current harmonics introduced by automotive PMSMs are primarily 5th and 7th harmonics. In this step, the first angle of the 5th harmonic and the second angle of the 7th harmonic of the PMSM are determined. These first and second angles represent the rotor electrical angles of the PMSM at the current moment, and are signals measured by sensors. These signals are true values ​​and reflect the current rotational speed of the PMSM. Furthermore, step 101 can be executed when the operating conditions of the PMSM change; otherwise, when the operating conditions remain unchanged, the 5th and 7th harmonics can be injected into the PMSM based on the previously determined d-axis and q-axis harmonic voltages.

[0077] This step can be achieved through the following steps (1) to (4), including:

[0078] (1) Taking the dq axis rotation coordinate system of the permanent magnet synchronous motor as the reference, the fundamental magnetic flux of the permanent magnet synchronous motor rotates counterclockwise at a speed of ω.

[0079] (2) Determine the clockwise rotation angle of the 5th harmonic relative to the dq axis rotation coordinate system when the 5th harmonic rotates clockwise at a speed of 5ω, and determine the counterclockwise rotation angle of the 7th harmonic relative to the dq axis rotation coordinate system when the 7th harmonic rotates at a speed of 7ω.

[0080] For example, please refer to Figure 2 Since the fundamental flux linkage of the permanent magnet synchronous motor rotates counterclockwise at a speed of ω, while the 5th harmonic rotates clockwise at a speed of 5ω, the clockwise rotation speed of the 5th harmonic relative to the dq rotating coordinate system is 6ω, and the clockwise rotation angle of the 5th harmonic relative to the dq rotating coordinate system is 6ωt. When the 7th harmonic rotates at a speed of 7ω, the counterclockwise rotation speed of the 7th harmonic relative to the dq axis rotating coordinate system is 6ω, which is converted to a clockwise rotation speed of -6ω, and the counterclockwise rotation angle of the 7th harmonic relative to the dq axis rotating coordinate system is -6ωt.

[0081] (3) Based on the clockwise rotation angle, the initial phase of the 5th harmonic and the first compensation angle, determine the first angle of the 5th harmonic.

[0082] By determining the sum of the clockwise rotation angle 6ωt of the 5th harmonic relative to the dq rotating coordinate system, the initial phase of the 5th harmonic, and the first supplementary angle, we obtain the first angle of the 5th harmonic, which is expressed as 6ωt + θ. P +θ P_offset Where 6ωt is the clockwise rotation angle of the 5th harmonic relative to the dq rotating coordinate system, and θ is... P The initial phase of the 5th harmonic is θ. P_offset This is the first compensation angle.

[0083] (4) Based on the counterclockwise rotation angle, the initial phase of the 7th harmonic and the second compensation angle, determine the second angle of the 7th harmonic.

[0084] By determining the sum of the clockwise rotation angle -6ωt of the 7th harmonic relative to the dq rotating coordinate system, the initial phase of the 7th harmonic, and the second supplementary angle, we obtain the second angle of the 7th harmonic, which is expressed as -6ωt + θ. N +θ N_offset Where -6ωt is the clockwise rotation angle of the 7th harmonic relative to the dq rotating coordinate system, θ N The initial phase of the 7th harmonic is θ. N_offsetThis is the second compensation angle.

[0085] Both the first compensation angle and the second compensation angle can be set and changed as needed. In this embodiment, neither the first compensation angle nor the second compensation angle is specifically limited. Furthermore, the first compensation angle and the second compensation angle can be preset fixed values ​​or set according to the current operating conditions. The process of setting the first compensation angle and the second compensation angle according to the current operating conditions can be as follows: determine the operating conditions of the permanent magnet synchronous motor, and based on the operating conditions, determine the first compensation angle and the second compensation angle under the operating conditions. For example, the electromagnetic synchronous motor stores a compensation angle table, which stores the correspondence between the operating conditions, the first compensation angle, and the second compensation angle. Correspondingly, the step of determining the first compensation angle and the second compensation angle under the operating conditions can be as follows: based on the operating conditions, determine the first compensation angle and the second compensation angle corresponding to the operating conditions from the compensation angle table, thereby realizing different degrees of angle compensation under different operating conditions, making the solution of this application applicable to different operating conditions and improving the applicability of harmonic injection.

[0086] Step 102: Convert the first angle of the 5th harmonic and the second angle of the 7th harmonic from degrees to radians to obtain the third angle of the 5th harmonic and the fourth angle of the 7th harmonic.

[0087] For example, please refer to Figure 3 The first angle of the 5th harmonic and the second angle of the 7th harmonic are converted from degrees to radians to obtain the third angle of the 5th harmonic and the fourth angle of the 7th harmonic, so as to achieve harmonic angle extraction.

[0088] Step 103: Determine the harmonic voltage of the 5th harmonic and the harmonic voltage of the 7th harmonic.

[0089] The harmonic voltages of the 5th and 7th harmonics are measured using a voltage sensor.

[0090] Step 104: Based on the third angle, convert the harmonic voltage of the 5th harmonic into the dq axis rotation coordinate of the permanent magnet synchronous motor to obtain the voltage of the 5th harmonic on the d axis and the voltage on the q axis respectively.

[0091] From a third perspective, the fifth harmonic voltage is converted into the dq-axis rotational coordinates of the permanent magnet synchronous motor using the following formula, yielding the fifth harmonic voltages on the d-axis and q-axis respectively:

[0092] Formula 1: U d_P =U P cos(θ1)-U P sin(θ1)

[0093] U q_P =UP sin(θ1)+U P cos(θ1)

[0094] Among them, U d_P U is the voltage of the 5th harmonic on the d-axis. q_P U is the voltage of the 5th harmonic on the q-axis; θ1 is the third angle, U P The harmonic voltage is the 5th harmonic. Since θ1 = 6ωt + θ P +θ P_offset Therefore, Formula 1 can be transformed into:

[0095] U d_P =U P cos(6ωt+θ P +θ P_offset )-U P sin(6ωt+θ P +θ P_offset )

[0096] U q_P =U P sin(6ωt+θ P +θ P_offset )+U P cos(6ωt+θ P +θ P_offset )

[0097] Where 6ωt is the clockwise rotation angle of the 5th harmonic relative to the dq rotating coordinate system, and θ P The initial phase of the 5th harmonic is θ. P_offset This is the first compensation angle.

[0098] In one possible implementation, after determining the voltages of the 5th harmonic on the d-axis and q-axis, the voltages of the 5th harmonic on the d-axis and q-axis are verified. If the verification of the voltages of the 5th harmonic on the d-axis and q-axis passes, step 105 is executed. If the verification of the voltages of the 5th harmonic on the d-axis and q-axis fails, step 101 is re-executed, thereby improving the accuracy of the determined voltages of the 5th harmonic on the d-axis and q-axis. The process of verifying the voltages of the 5th harmonic on the d-axis and q-axis can be as follows: determine the first voltage range of the 5th harmonic on the d-axis and the second voltage range on the q-axis; if the voltage of the 5th harmonic on the d-axis is within the first voltage range and the voltage of the 5th harmonic on the q-axis is within the second voltage range, then the verification of the voltages of the 5th harmonic on the d-axis and q-axis is successful; if the voltage of the 5th harmonic on the d-axis is not within the first voltage range or the voltage of the 5th harmonic on the q-axis is not within the second voltage range, then the verification of the voltages of the 5th harmonic on the d-axis and q-axis is unsuccessful.

[0099] Step 105: Based on the fourth angle, convert the harmonic voltage of the 7th harmonic into the dq rotating coordinate system of the permanent magnet synchronous motor to obtain the voltage of the 7th harmonic on the d-axis and the voltage on the q-axis respectively.

[0100] Based on the fourth angle, the harmonic voltage of the 7th harmonic is converted into the dq-axis rotational coordinates of the permanent magnet synchronous motor using the following formula two, yielding the voltages of the 7th harmonic on the d-axis and q-axis respectively:

[0101] Formula 2: U d_N =U N cos(θ2)-U N sin(θ2)

[0102] U q_N =U N sin(θ2)+U N cos(θ2)

[0103] Among them, U d_N U is the voltage of the 7th harmonic on the d-axis. q_N U is the voltage of the 7th harmonic on the q-axis; θ2 is the fourth angle. N The harmonic voltage is the 7th harmonic. Since θ² = -6ωt + θ N +θ N_offset Therefore, Formula 2 can be transformed into:

[0104] U d_N =U N cos(-6ωt+θ N +θ N_offset )-U N sin(-6ωt+θ N +θ N_offset )

[0105] U q_N =U N sin(-6ωt+θ N +θ N_offset )+U N cos(-6ωt+θ N +θ N_offset )

[0106] Where -6ωt is the clockwise rotation angle of the 7th harmonic relative to the dq rotating coordinate system, θ N The initial phase of the 7th harmonic is θ. N_offset This is the second compensation angle.

[0107] In one possible implementation, after determining the voltages of the 7th harmonic on the d-axis and q-axis, the voltages of the 7th harmonic on the d-axis and q-axis are verified. If the verification of the voltages of the 7th harmonic on the d-axis and q-axis passes, step 107 is executed. If the verification of the voltages of the 7th harmonic on the d-axis and q-axis fails, step 101 is re-executed, thereby improving the accuracy of the determined voltages of the 7th harmonic on the d-axis and q-axis. The process of verifying the voltages of the 7th harmonic on the d-axis and q-axis can be as follows: determine the third voltage range and the fourth voltage range of the 7th harmonic on the d-axis; if the voltage of the 7th harmonic on the d-axis is within the third voltage range and the voltage of the 7th harmonic on the q-axis is within the fourth voltage range, the verification of the voltages of the 7th harmonic on the d-axis and q-axis is deemed successful; if the voltage of the 7th harmonic on the d-axis is not within the third voltage range or the voltage of the 7th harmonic on the q-axis is not within the fourth voltage range, the verification of the voltages of the 7th harmonic on the d-axis and q-axis is deemed unsuccessful.

[0108] Step 106: Determine the harmonic voltage on the d-axis based on the voltage of the 5th harmonic and the voltage of the 7th harmonic on the d-axis.

[0109] In one possible implementation, the d-axis harmonic voltage is obtained by summing the voltages of the 5th harmonic and the 7th harmonic on the d-axis; the d-axis harmonic voltage is expressed as follows:

[0110] U d =U d_N +U d_P

[0111] Among them, U d U is the harmonic voltage along the d-axis. d_P U is the voltage of the 5th harmonic on the d-axis. d_N The voltage of the 7th harmonic on the d-axis.

[0112] In another possible implementation, the voltages of the 5th and 7th harmonics on the d-axis are weighted and summed based on the first and second weights corresponding to the 5th and 7th harmonics, respectively, to obtain the harmonic voltages on the d-axis. The first and second weights corresponding to the 5th and 7th harmonics can be set and changed as needed; in this embodiment, the first and second weights are not specifically limited. Alternatively, the first and second weights can also be set based on the operating conditions of the permanent magnet synchronous motor. Accordingly, the process can be: determining the operating conditions of the permanent magnet synchronous motor, and based on these conditions, determining the first and second weights corresponding to the 5th and 7th harmonics under those conditions. Alternatively, the first and second weights can also be set based on the third angle of the 5th harmonic and the fourth angle of the 7th harmonic. Correspondingly, the process can be as follows: based on the third angle of the 5th harmonic and the fourth angle of the 7th harmonic, determine the degree of influence of the 5th and 7th harmonics on the permanent magnet synchronous motor; based on the degree of influence of the 5th and 7th harmonics on the permanent magnet synchronous motor, determine the first and second weights corresponding to the 5th and 7th harmonics respectively. The degree of influence is positively correlated with the weight, that is, the greater the influence of the harmonic on the permanent magnet synchronous motor, the greater its corresponding weight; and the smaller the influence of the harmonic on the permanent magnet synchronous motor, the smaller its corresponding weight.

[0113] For example, please continue to refer to Figure 3 Steps 103-106 above are for calculating harmonic voltage. In one possible implementation, the historical 5th harmonic voltage and 7th harmonic voltage on the d-axis of the permanent magnet synchronous motor can also be obtained. The d-axis harmonic voltage is obtained by weighted summing of the 5th harmonic voltage, the 7th harmonic voltage, and the historical 5th harmonic voltage and 7th harmonic voltage on the d-axis of the permanent magnet synchronous motor.

[0114] Step 107: Determine the harmonic voltage on the q-axis based on the voltage of the 5th harmonic and the voltage of the 7th harmonic on the q-axis.

[0115] In one possible implementation, the q-axis harmonic voltage is obtained by summing the voltages of the 5th harmonic and the 7th harmonic on the q-axis; the q-axis harmonic voltage is expressed as follows:

[0116] U q =U q_N +U q_P

[0117] Among them, U q U is the harmonic voltage along the q-axis. q_P U is the voltage of the 5th harmonic on the q-axis. q_N The voltage of the 7th harmonic on the q-axis.

[0118] In another possible implementation, the voltage of the 5th harmonic on the q-axis and the voltage of the 7th harmonic on the q-axis are weighted and summed based on the first weight and the second weight corresponding to the 5th harmonic and the 7th harmonic, respectively, to obtain the harmonic voltage on the q-axis.

[0119] In one possible implementation, the voltage of the 5th harmonic on the q-axis and the voltage of the 7th harmonic on the q-axis in the history of the permanent magnet synchronous motor can also be obtained. The harmonic voltage on the q-axis is obtained by weighted summing of the voltage of the 5th harmonic on the q-axis, the voltage of the 7th harmonic on the q-axis, and the voltage of the 5th harmonic on the q-axis and the voltage of the 7th harmonic on the q-axis in the history of the permanent magnet synchronous motor.

[0120] Step 108: Based on the harmonic voltage of the d-axis and the harmonic voltage of the q-axis, inject the 5th and 7th harmonics into the permanent magnet synchronous motor.

[0121] For example, please continue to refer to Figure 3 Determine whether the harmonic algorithm enable condition is met; if the harmonic algorithm enable condition is met, apply gradient constraints to the harmonic voltages on the d-axis and q-axis; if the harmonic algorithm enable condition is not met, output the harmonic voltage as 0.

[0122] In the embodiments of this application, when determining the harmonic voltages of the 5th harmonic on the d-axis and q-axis, and when determining the harmonic voltages of the 7th harmonic on the d-axis and q-axis, the current angle of the permanent magnet synchronous motor is taken into consideration. Since the current angle of the permanent magnet synchronous motor is closely related to its rotational speed, this application can adjust the harmonic injection situation in a timely manner when the rotational speed of the permanent magnet synchronous motor changes, thereby realizing harmonic injection based on the operating conditions (rotational speed) of the permanent magnet synchronous motor, thus improving the harmonic injection effect of the permanent magnet synchronous motor.

[0123] Please refer to Figure 4 This document illustrates a flowchart of a harmonic injection method for a permanent magnet synchronous motor, as shown in an exemplary embodiment of this application. (Reference) Figure 4 The method includes:

[0124] Step 401: Determine the first angle of the 5th harmonic and the second angle of the 7th harmonic of the permanent magnet synchronous motor. Both the first angle of the 5th harmonic and the second angle of the 7th harmonic are in angle format.

[0125] In some embodiments, this step is the same as step 101, and will not be described again here.

[0126] Step 402: The permanent magnet synchronous motor converts the first angle of the 5th harmonic and the second angle of the 7th harmonic from the degree system to the radian system to obtain the third angle of the 5th harmonic and the fourth angle of the 7th harmonic.

[0127] In some embodiments, this step is the same as step 102, and will not be described again here.

[0128] Step 403: Determine the harmonic voltage of the 5th harmonic and the harmonic voltage of the 7th harmonic of the permanent magnet synchronous motor.

[0129] In some embodiments, this step is the same as step 103, and will not be described again here.

[0130] Step 404: Based on the third angle, the harmonic voltage of the 5th harmonic is converted into the dq axis rotation coordinate of the permanent magnet synchronous motor, and the voltages of the 5th harmonic on the d axis and q axis are obtained respectively.

[0131] In some embodiments, this step is the same as step 104, and will not be described again here.

[0132] Step 405: Based on the fourth angle, the harmonic voltage of the 7th harmonic is converted into the dq rotating coordinate system of the permanent magnet synchronous motor, and the voltages of the 7th harmonic on the d-axis and q-axis are obtained respectively.

[0133] In some embodiments, this step is the same as step 105, and will not be described again here.

[0134] Step 406: The permanent magnet synchronous motor determines the harmonic voltage on the d-axis based on the voltage of the 5th harmonic and the voltage of the 7th harmonic on the d-axis.

[0135] In some embodiments, this step is the same as step 106, and will not be described again here.

[0136] Step 407: The permanent magnet synchronous motor determines the harmonic voltage on the q-axis based on the voltage of the 5th harmonic and the voltage of the 7th harmonic on the q-axis.

[0137] In some embodiments, this step is the same as step 107, and will not be described again here.

[0138] Step 408: Determine the operating conditions of the permanent magnet synchronous motor.

[0139] The operating conditions of a permanent magnet synchronous motor refer to the working state of the permanent magnet synchronous motor under conditions that are directly related to its operation, including a description of a series of load states that the permanent magnet synchronous motor bears in a specific working environment.

[0140] Step 409: Based on the operating conditions, determine the maximum motor speed, minimum motor speed, and motor speed difference of the permanent magnet synchronous motor under the operating conditions.

[0141] The permanent magnet synchronous motor stores a tachometer, which stores the correspondence between the operating condition and the maximum motor speed, minimum motor speed, and motor speed difference. Accordingly, in this step, the permanent magnet synchronous motor determines the maximum motor speed, minimum motor speed, and motor speed difference corresponding to the operating condition from the tachometer based on the operating condition.

[0142] Since this application can determine the maximum motor speed, minimum motor speed, and motor speed difference under the operating conditions of the permanent magnet synchronous motor, the harmonic injection algorithm of this application can be applied to different operating conditions, thereby improving the practicality of the harmonic injection algorithm. In other words, the harmonic injection of this application is highly practical.

[0143] Step 410: Determine the current speed of the permanent magnet synchronous motor.

[0144] It should be noted that steps 409 and 410 do not have a strict chronological order. Step 409 can be executed first, followed by step 410, or vice versa. Furthermore, when the operating conditions of the permanent magnet synchronous motor change, step 409 is executed once; if the operating conditions remain unchanged, step 409 does not need to be executed repeatedly.

[0145] Step 411: Based on the maximum motor speed, minimum motor speed, motor speed difference, and current permanent magnet synchronous motor speed, determine whether the permanent magnet synchronous motor meets the harmonic injection algorithm enable requirement.

[0146] The permanent magnet synchronous motor determines the difference between the maximum motor speed and the difference between the motor speeds to obtain the first motor speed; it determines the sum of the minimum motor speed and the difference between the motor speeds to obtain the second motor speed; if the current speed is not less than the first motor speed and not greater than the second motor speed, the permanent magnet synchronous motor determines that it satisfies the harmonic injection algorithm enabling condition; if the current speed is less than the first motor speed or greater than the second motor speed, the permanent magnet synchronous motor determines that it does not satisfy the harmonic injection algorithm enabling condition.

[0147] Accordingly, this step can be achieved using the following formula three:

[0148] Formula 3: n maxhi -Δ≤|n|≤n minhi +Δ

[0149] Where, n maxhi To inject harmonics to the maximum motor speed, n minhi The minimum motor speed for harmonic injection is given, Δ is the motor speed difference due to harmonic injection, and n is the current speed of the permanent magnet synchronous motor. For example, please refer to... Figure 5 The permanent magnet synchronous motor will nmaxhi n minhi The absolute values ​​of Δ and n are input into the harmonic injection algorithm enabling process, and the output is the recognition result. The recognition result indicates whether the harmonic injection algorithm is enabled or not.

[0150] Step 412: When the permanent magnet synchronous motor meets the harmonic injection algorithm enable condition, the permanent magnet synchronous motor performs gradient limiting on the harmonic voltage of the d-axis and the harmonic voltage of the q-axis, and outputs the gradient-limited harmonic voltage of the d-axis and the gradient-limited harmonic voltage of the q-axis, so that the gradient-limited harmonic voltage of the d-axis and the gradient-limited harmonic voltage of the q-axis eliminate the 5th harmonic current harmonic and the 7th harmonic current harmonic.

[0151] When the absolute value of the current speed of the permanent magnet synchronous motor satisfies Formula 3 above, the harmonic injection algorithm is enabled, and then the output dq axis harmonic voltage is gradient limited to make the output voltage signal smoother in order to eliminate the 5th and 7th current harmonics.

[0152] Step 413: When the permanent magnet synchronous motor does not meet the harmonic injection algorithm enable condition, the output harmonic voltage of the permanent magnet synchronous motor is 0.

[0153] When the absolute value of the current speed of the permanent magnet synchronous motor does not satisfy the above formula, the harmonic injection algorithm is not enabled, and the output dq axis harmonic voltage is 0.

[0154] In this embodiment, the current angle of the permanent magnet synchronous motor (PMSM) is considered when determining the harmonic voltages of the 5th harmonic on the d-axis and q-axis, and when determining the harmonic voltages of the 7th harmonic on the d-axis and q-axis. Since the current angle of the PMSM is closely related to its rotational speed, this application can adjust the harmonic injection situation in a timely manner when the rotational speed of the PMSM changes. This allows for harmonic injection based on the operating conditions (rotational speed) of the PMSM, thereby improving the harmonic injection effect. However, related technologies generally lack consideration for the specific operating conditions of the PMSM, resulting in poor practicality of harmonic injection. This application, by considering the specific operating conditions of the PMSM, improves the practicality of the harmonic injection method.

[0155] Please refer to Figure 6 This illustration shows a block diagram of a harmonic injection device for a permanent magnet synchronous motor, as illustrated in an exemplary embodiment of this application. The device includes:

[0156] The first determining module 601 is used to determine the first angle of the 5th harmonic and the second angle of the 7th harmonic of the permanent magnet synchronous motor. Both the first angle of the 5th harmonic and the second angle of the 7th harmonic are in angle form.

[0157] The first conversion module 602 is used to convert the first angle of the 5th harmonic and the second angle of the 7th harmonic from degrees to radians to obtain the third angle of the 5th harmonic and the fourth angle of the 7th harmonic.

[0158] The second determining module 603 is used to determine the harmonic voltage of the 5th harmonic and the harmonic voltage of the 7th harmonic;

[0159] The second conversion module 604 is used to convert the fifth harmonic voltage into the dq axis rotation coordinate of the permanent magnet synchronous motor based on the third angle, so as to obtain the voltage of the fifth harmonic on the d axis and the voltage on the q axis respectively.

[0160] The third conversion module 605 is used to convert the harmonic voltage of the 7th harmonic into the dq rotating coordinate system of the permanent magnet synchronous motor based on the fourth angle, so as to obtain the voltage of the 7th harmonic on the d-axis and the voltage on the q-axis respectively.

[0161] The third determining module 606 is used to determine the harmonic voltage on the d-axis based on the voltage of the 5th harmonic on the d-axis and the voltage of the 7th harmonic on the d-axis.

[0162] The fourth determining module 607 is used to determine the harmonic voltage on the q-axis based on the voltage of the 5th harmonic on the q-axis and the voltage of the 7th harmonic on the q-axis.

[0163] The injection module 608 is used to inject the 5th and 7th harmonics into the permanent magnet synchronous motor based on the harmonic voltage of the d-axis and the harmonic voltage of the q-axis.

[0164] In one possible implementation, the injection module 608 is used to determine the operating conditions of the permanent magnet synchronous motor; based on the operating conditions, it determines the maximum motor speed, minimum motor speed, and motor speed difference of the permanent magnet synchronous motor under the operating conditions for harmonic injection; it determines the current speed of the permanent magnet synchronous motor; based on the maximum motor speed, minimum motor speed, motor speed difference, and current speed, it determines whether the permanent magnet synchronous motor satisfies the harmonic injection algorithm enabling condition; if the permanent magnet synchronous motor satisfies the harmonic injection algorithm enabling condition, it performs gradient limiting on the harmonic voltages of the d-axis and q-axis, and outputs the gradient-limited harmonic voltages of the d-axis and q-axis, so that the gradient-limited harmonic voltages of the d-axis and q-axis eliminate the 5th harmonic current harmonic and the 7th harmonic current harmonic.

[0165] In another possible implementation, the injection module 608 is used to determine the difference between the maximum motor speed and the difference between the motor speeds to obtain the first motor speed; determine the sum of the minimum motor speed and the difference between the motor speeds to obtain the second motor speed; and determine that the permanent magnet synchronous motor satisfies the harmonic injection algorithm enable condition when the current speed is not less than the first motor speed and not greater than the second motor speed.

[0166] In another possible implementation, the first determining module 601 is used to determine, with the dq-axis rotating coordinate system of the permanent magnet synchronous motor as a reference, the fundamental flux linkage of the permanent magnet synchronous motor rotates counterclockwise at a speed of ω; determine the clockwise rotation angle of the 5th harmonic relative to the dq-axis rotating coordinate system when the 5th harmonic rotates clockwise at a speed of 5ω, and determine the counterclockwise rotation angle of the 7th harmonic relative to the dq-axis rotating coordinate system when the 7th harmonic rotates at a speed of 7ω; determine the first angle of the 5th harmonic based on the clockwise rotation angle, the initial phase of the 5th harmonic, and the first compensation angle; and determine the second angle of the 7th harmonic based on the counterclockwise rotation angle, the initial phase of the 7th harmonic, and the second compensation angle.

[0167] In another possible implementation, the second conversion module 604 is used to convert the fifth harmonic voltage into the dq-axis rotational coordinates of the permanent magnet synchronous motor based on the third angle using the following formula: to obtain the fifth harmonic voltages on the d-axis and q-axis respectively.

[0168] Formula 1: U d_P =U P cos(θ1)-U P sin(θ1)

[0169] U q_P =U P sin(θ1)+U P cos(θ1)

[0170] Among them, U d_P U is the voltage of the 5th harmonic on the d-axis. q_P U is the voltage of the 5th harmonic on the q-axis; θ1 is the third angle, U P The harmonic voltage is the 5th harmonic.

[0171] The third conversion module 605 is used to convert the 7th harmonic voltage into the dq axis rotation coordinates of the permanent magnet synchronous motor based on the fourth angle using the following formula two, to obtain the 7th harmonic voltages on the d-axis and q-axis respectively:

[0172] Formula 2: U d_N =U N cos(θ2)-U N sin(θ2)

[0173] U q_N =U N sin(θ2)+U N cos(θ2)

[0174] Among them, U d_N U is the voltage of the 7th harmonic on the d-axis.q_N U is the voltage of the 7th harmonic on the q-axis; θ2 is the fourth angle. N The harmonic voltage is the 7th harmonic.

[0175] In the embodiments of this application, when determining the harmonic voltages of the 5th harmonic on the d-axis and q-axis, and when determining the harmonic voltages of the 7th harmonic on the d-axis and q-axis, the current angle of the permanent magnet synchronous motor is taken into consideration. Since the current angle of the permanent magnet synchronous motor is closely related to its rotational speed, this application can adjust the harmonic injection situation in a timely manner when the rotational speed of the permanent magnet synchronous motor changes, thereby realizing harmonic injection based on the operating conditions (rotational speed) of the permanent magnet synchronous motor, thus improving the harmonic injection effect of the permanent magnet synchronous motor.

[0176] It should be noted that the harmonic injection device for permanent magnet synchronous motors provided in the above embodiments is only illustrated by the division of the above functional modules when performing harmonic injection into the permanent magnet synchronous motor. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the permanent magnet synchronous motor can be divided into different functional modules to complete all or part of the functions described above. In addition, the harmonic injection device for permanent magnet synchronous motors provided in the above embodiments and the harmonic injection method embodiments for permanent magnet synchronous motors belong to the same concept, and the specific implementation process is detailed in the method embodiments, which will not be repeated here.

[0177] Figure 7 This is a structural block diagram of a permanent magnet synchronous motor 700 provided in an embodiment of this application. Typically, the permanent magnet synchronous motor 700 includes a processor (central processing unit, CPU) 701 and a memory 702. The memory 702 stores at least one line of program code, which is loaded and executed by the processor 701 to implement the methods provided in the above-described method embodiments. Of course, the permanent magnet synchronous motor 700 may also have wired or wireless network interfaces, a keyboard, and input / output interfaces for input and output. The permanent magnet synchronous motor 700 may also include other components for implementing device functions, which will not be elaborated upon here.

[0178] Those skilled in the art will understand that Figure 7 The structure shown does not constitute a limitation on the permanent magnet synchronous motor 700, and may include more or fewer components than shown, or combine certain components, or use different component arrangements.

[0179] This application also provides a new energy vehicle, which includes the aforementioned permanent magnet synchronous motor. This new energy vehicle can be a hybrid vehicle or a pure electric vehicle.

[0180] This application also provides a computer-readable storage medium storing at least one piece of program code, which is loaded and executed by a processor to implement the harmonic injection method for a permanent magnet synchronous motor as described in any of the above implementations. Optionally, the storage medium may be a non-transitory computer-readable storage medium, such as ROM (Read-Only Memory), RAM (Random Access Memory), CD-ROM (Compact Disc Read-Only Memory), magnetic tape, floppy disk, and optical data storage devices.

[0181] This application also provides a computer program product that stores at least one piece of program code, which is loaded and executed by a processor to implement the harmonic injection method for permanent magnet synchronous motors shown in the above embodiments.

[0182] In some embodiments, the computer program product involved in the present application embodiments may be deployed and executed on a permanent magnet synchronous motor, or on multiple permanent magnet synchronous motors located in one location, or on multiple permanent magnet synchronous motors distributed in multiple locations and interconnected through a communication network. Multiple permanent magnet synchronous motors distributed in multiple locations and interconnected through a communication network may form a blockchain system.

[0183] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0184] The above description is only for the purpose of enabling those skilled in the art to understand the technical solution of this application, and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A harmonic injection method for a permanent magnet synchronous motor, characterized in that, The method includes: The first angle of the 5th harmonic and the second angle of the 7th harmonic of the permanent magnet synchronous motor are determined, wherein the first angle of the 5th harmonic and the second angle of the 7th harmonic are both in angle system. The first angle of the 5th harmonic and the second angle of the 7th harmonic are converted from degrees to radians to obtain the third angle of the 5th harmonic and the fourth angle of the 7th harmonic. Determine the harmonic voltage of the 5th harmonic and the harmonic voltage of the 7th harmonic; Based on the third angle, the harmonic voltage of the 5th harmonic is converted into the dq axis rotation coordinate of the permanent magnet synchronous motor to obtain the voltage of the 5th harmonic on the d axis and the voltage on the q axis respectively; Based on the fourth angle, the harmonic voltage of the 7th harmonic is converted into the dq rotating coordinate system of the permanent magnet synchronous motor to obtain the voltage of the 7th harmonic on the d-axis and the voltage on the q-axis, respectively. Based on the voltage of the 5th harmonic on the d-axis and the voltage of the 7th harmonic on the d-axis, the harmonic voltage on the d-axis is determined. Based on the voltage of the 5th harmonic on the q-axis and the voltage of the 7th harmonic on the q-axis, determine the harmonic voltage on the q-axis; Based on the harmonic voltage of the d-axis and the harmonic voltage of the q-axis, the permanent magnet synchronous motor is injected with the 5th and 7th harmonics. The determination of the first angle of the 5th harmonic and the second angle of the 7th harmonic of the permanent magnet synchronous motor includes: Using the dq-axis rotational coordinate system of the permanent magnet synchronous motor as a reference, the fundamental flux linkage of the permanent magnet synchronous motor rotates counterclockwise at a speed of ω; the clockwise rotation angle of the 5th harmonic relative to the dq-axis rotational coordinate system when the 5th harmonic rotates clockwise at a speed of 5ω is determined, and the counterclockwise rotation angle of the 7th harmonic relative to the dq-axis rotational coordinate system when the 7th harmonic rotates at a speed of 7ω is determined; based on the clockwise rotation angle, the initial phase of the 5th harmonic, and the first compensation angle, the first angle of the 5th harmonic is determined; based on the counterclockwise rotation angle, the initial phase of the 7th harmonic, and the second compensation angle, the second angle of the 7th harmonic is determined.

2. The method according to claim 1, characterized in that, The injection of 5th and 7th harmonics into the permanent magnet synchronous motor based on the harmonic voltages of the d-axis and q-axis includes: Determine the operating conditions of the permanent magnet synchronous motor; Based on the operating conditions, determine the maximum motor speed, minimum motor speed, and motor speed difference of the permanent magnet synchronous motor under the operating conditions for harmonic injection. Determine the current permanent magnet synchronous motor speed; Based on the maximum motor speed, the minimum motor speed, the motor speed difference, and the current permanent magnet synchronous motor speed, determine whether the permanent magnet synchronous motor satisfies the harmonic injection algorithm enable; When the permanent magnet synchronous motor satisfies the harmonic injection algorithm enable condition, the harmonic voltages of the d-axis and the q-axis are gradient-limited, and the gradient-limited harmonic voltages of the d-axis and the q-axis are output, so that the gradient-limited harmonic voltages of the d-axis and the q-axis eliminate the current harmonics of the 5th and 7th harmonics.

3. The method according to claim 2, characterized in that, The step of determining whether the permanent magnet synchronous motor satisfies the harmonic injection algorithm enable condition based on the maximum motor speed, the minimum motor speed, the motor speed difference, and the current permanent magnet synchronous motor speed includes: The first motor speed is obtained by determining the difference between the maximum motor speed and the difference between the motor speeds; The second motor speed is obtained by summing the difference between the minimum motor speed and the motor speed. If the current rotational speed is not less than the rotational speed of the first motor and the current rotational speed is not greater than the rotational speed of the second motor, then the permanent magnet synchronous motor is determined to satisfy the harmonic injection algorithm enable.

4. The method according to claim 1, characterized in that, Based on the third angle, the harmonic voltage of the 5th harmonic is converted into the dq-axis rotational coordinates of the permanent magnet synchronous motor to obtain the voltages of the 5th harmonic on the d-axis and q-axis, respectively, including: Based on the aforementioned third angle, the harmonic voltage of the 5th harmonic is converted into the dq-axis rotational coordinates of the permanent magnet synchronous motor using the following formula, yielding the voltages of the 5th harmonic on the d-axis and q-axis respectively: Address:U d_P =U P cos(θ1)-U P sin(θ1) IN q_P =U P sin(θ1)+U P cos(θ1) Among them, U d_P U is the voltage of the 5th harmonic on the d-axis. q_P The voltage of the 5th harmonic on the q-axis is θ; θ1 is the third angle, U P The harmonic voltage of the 5th harmonic; Based on the fourth angle, the harmonic voltage of the 7th harmonic is converted into the dq rotating coordinate system of the permanent magnet synchronous motor to obtain the voltages of the 7th harmonic on the d-axis and q-axis, respectively, including: Based on the aforementioned fourth angle, the harmonic voltage of the 7th harmonic is converted into the dq-axis rotational coordinates of the permanent magnet synchronous motor using the following formula two, yielding the voltages of the 7th harmonic on the d-axis and q-axis respectively: Formula 2: U d_N =U N cos(θ2)-U N sin(θ2) U q_N =U N sin(θ2)+U N cos(θ2) Among them, U d_N U is the voltage of the 7th harmonic on the d-axis. q_N θ2 is the voltage of the 7th harmonic on the q-axis; θ2 is the fourth angle, U N The harmonic voltage of the 7th harmonic is given.

5. A harmonic injection device for a permanent magnet synchronous motor, characterized in that, The device includes: The first determining module is used to determine the first angle of the 5th harmonic and the second angle of the 7th harmonic of the permanent magnet synchronous motor, wherein the first angle of the 5th harmonic and the second angle of the 7th harmonic are both in angle system. The first conversion module is used to convert the first angle of the 5th harmonic and the second angle of the 7th harmonic from degrees to radians to obtain the third angle of the 5th harmonic and the fourth angle of the 7th harmonic. The second determining module is used to determine the harmonic voltage of the 5th harmonic and the harmonic voltage of the 7th harmonic; The second conversion module is used to convert the harmonic voltage of the 5th harmonic into the dq axis rotation coordinate of the permanent magnet synchronous motor based on the third angle, so as to obtain the voltage of the 5th harmonic on the d axis and the voltage on the q axis respectively. The third conversion module is used to convert the harmonic voltage of the 7th harmonic into the dq rotating coordinate system of the permanent magnet synchronous motor based on the fourth angle, so as to obtain the voltage of the 7th harmonic on the d-axis and the voltage on the q-axis respectively. The third determining module is used to determine the harmonic voltage on the d-axis based on the voltage of the 5th harmonic on the d-axis and the voltage of the 7th harmonic on the d-axis. The fourth determining module is used to determine the harmonic voltage on the q-axis based on the voltage of the 5th harmonic on the q-axis and the voltage of the 7th harmonic on the q-axis. An injection module is used to inject the 5th and 7th harmonics into the permanent magnet synchronous motor based on the harmonic voltage of the d-axis and the harmonic voltage of the q-axis. The first determining module is configured to: use the dq-axis rotation coordinate system of the permanent magnet synchronous motor as a reference, with the fundamental flux linkage of the permanent magnet synchronous motor rotating counterclockwise at a speed of ω; determine the clockwise rotation angle of the 5th harmonic relative to the dq-axis rotation coordinate system when the 5th harmonic rotates clockwise at a speed of 5ω, and determine the counterclockwise rotation angle of the 7th harmonic relative to the dq-axis rotation coordinate system when the 7th harmonic rotates at a speed of 7ω; determine a first angle of the 5th harmonic based on the clockwise rotation angle, the initial phase of the 5th harmonic, and a first compensation angle; and determine a second angle of the 7th harmonic based on the counterclockwise rotation angle, the initial phase of the 7th harmonic, and a second compensation angle.

6. A permanent magnet synchronous motor, characterized in that, The permanent magnet synchronous motor includes a processor and a memory, wherein the memory stores at least one piece of program code, which is loaded and executed by the processor to implement the harmonic injection method of the permanent magnet synchronous motor as described in any one of claims 1 to 4.

7. A new energy vehicle, characterized in that, The new energy vehicle includes the permanent magnet synchronous motor as described in claim 6.

8. A computer-readable storage medium, characterized in that, The storage medium stores at least one piece of program code, which is loaded and executed by a processor to implement the harmonic injection method for a permanent magnet synchronous motor as described in any one of claims 1 to 4.

9. A computer program product, characterized in that, The product stores at least one piece of program code, which is executed by a processor to implement the harmonic injection method for a permanent magnet synchronous motor as described in any one of claims 1 to 4.

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