Motor control method and apparatus, vehicle, and storage medium

Abstract

Embodiments of the present application disclose a motor control method and apparatus, a vehicle, and a storage medium. The method comprises: converting three-phase currents outputted by a motor into a D-axis output current and a Q-axis output current of the motor; on the basis of the D-axis output current and the Q-axis output current, determining a D-axis high-order harmonic voltage and a Q-axis high-order harmonic voltage; on the basis of a target torque of the motor, determining a D-axis target voltage and a Q-axis target voltage of the motor; calculating a difference between the D-axis target voltage and the D-axis high-order harmonic voltage, and obtaining a D-axis input voltage of the motor; calculating a difference between the Q-axis target voltage and the Q-axis high-order harmonic voltage, and obtaining a Q-axis input voltage of the motor; and converting the D-axis input voltage and the Q-axis input voltage into three-phase input voltages of the motor. It can be understood that removing a high-order harmonic voltage from a target voltage of a motor attenuates high-order harmonics, thereby attenuating a harmonic torque of the motor, and accordingly greatly mitigating the problem of torque ripple in the motor.

Description

A motor control method, device, vehicle, and storage medium

[0001] This application claims priority to Chinese Patent Application No. 202510065883.2, filed on January 15, 2025 with the State Intellectual Property Office of China, entitled “A Motor Control Method, Apparatus, Vehicle and Storage Medium”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of vehicle technology, and more specifically to a motor control method, device, vehicle, and storage medium. Background Technology

[0003] New energy vehicles (which may also be referred to as "vehicles" in this article) typically include a motor and a power battery. The motor generally uses a three-phase AC motor. Since the power battery usually outputs direct current (DC), while the motor requires three-phase AC input, vehicles generally need to convert DC to AC; this process is called inversion. Vehicles typically achieve this inversion through an inverter. An inverter usually consists of an inverter circuit, which is generally composed of power semiconductor devices (Insulated Gate Bipolar Transistors, IGBTs).

[0004] During the inverter process, to prevent short circuits in the inverter, the control signals typically require a dead time, ensuring that the IGBTs used for inversion are simultaneously turned off. Each inverter cycle has a dead time, and each IGBT turn-on requires a certain on-state voltage drop. Due to the high switching frequency of the IGBTs, there are numerous inverter cycles per unit time. The combined effects of the dead time and on-state voltage drop generate high-order harmonics in the motor's input voltage. These harmonics can cause harmonic torque in the motor, leading to torque pulsation. Therefore, high-order harmonics should be suppressed.

[0005] In related technologies, the impact of higher harmonics on the motor is generally reduced by adjusting the dead time of the IGBT in the inverter. Although this solution can reduce higher harmonics, the dead time of the IGBT still exists, causing the motor to still generate harmonic torque, thus causing torque pulsation in the motor.

[0006] It should be noted that the information disclosed in the background section of this application is intended only to enhance the understanding of the general background of this application, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] In view of this, this application provides a motor control method, device, vehicle, and storage medium to help solve the problem that, during the process of converting DC power to AC power (i.e., inversion), the IGBTs in the inverter have dead time and on-state voltage drop, resulting in high-order harmonics in the motor's input voltage, causing harmonic torque and thus motor torque pulsation.

[0008] In a first aspect, embodiments of this application provide a motor control method, wherein the motor is a three-phase AC motor, and the method includes:

[0009] The three-phase current output by the motor is converted into the D-axis output current and Q-axis output current of the motor. The D-axis is in the same direction as the magnetic flux of the motor rotor, and the Q-axis is perpendicular to the magnetic flux of the motor rotor.

[0010] The higher harmonic voltages of the D-axis and Q-axis are determined based on the D-axis output current and the Q-axis output current.

[0011] Based on the target torque of the motor, determine the target voltage of the motor on the D-axis and the target voltage on the Q-axis;

[0012] The difference between the D-axis target voltage and the D-axis higher harmonic voltage is calculated to obtain the D-axis input voltage of the motor; the difference between the Q-axis target voltage and the Q-axis higher harmonic voltage is calculated to obtain the Q-axis input voltage of the motor.

[0013] The D-axis input voltage and the Q-axis input voltage are converted into the three-phase input voltage of the motor.

[0014] In one possible implementation, determining the D-axis higher harmonic voltage and the Q-axis higher harmonic voltage based on the D-axis output current and the Q-axis output current includes:

[0015] The higher harmonic mapping currents of the D-axis and Q-axis are extracted from the output current of the D-axis and the output current of the Q-axis respectively by the transformation matrix.

[0016] The higher harmonic mapping current of the D-axis and the higher harmonic mapping current of the Q-axis are integrated by a proportional-integral controller to obtain the higher harmonic mapping voltage of the D-axis and the higher harmonic mapping voltage of the Q-axis.

[0017] The D-axis higher harmonic mapping voltage and the Q-axis higher harmonic mapping voltage are converted into D-axis higher harmonic voltage and Q-axis higher harmonic voltage using an inverse transformation matrix.

[0018] In one possible implementation, determining the D-axis higher harmonic voltage and the Q-axis higher harmonic voltage based on the D-axis output current and the Q-axis output current includes:

[0019] The 5th harmonic mapping current of the D-axis and the 5th harmonic mapping current of the Q-axis are extracted from the D-axis output current and the Q-axis output current respectively using the first transformation matrix; and / or, the 7th harmonic mapping current of the D-axis and the 7th harmonic mapping current of the Q-axis are extracted from the D-axis output current and the Q-axis output current respectively using the second transformation matrix;

[0020] The 5th harmonic mapping current along the D-axis and the 5th harmonic mapping current along the Q-axis are integrated by a first proportional-integral controller to obtain the 5th harmonic mapping voltage along the D-axis and the 5th harmonic mapping voltage along the Q-axis; and / or, the 7th harmonic mapping current along the D-axis and the 7th harmonic mapping current along the Q-axis are integrated by a second proportional-integral controller to obtain the 7th harmonic mapping voltage along the D-axis and the 7th harmonic mapping voltage along the Q-axis.

[0021] The D-axis 5th harmonic mapped voltage and the Q-axis 5th harmonic mapped voltage are converted into D-axis 5th harmonic voltage and Q-axis 5th harmonic voltage using a first inverse transformation matrix; and / or, the D-axis 7th harmonic mapped voltage and the Q-axis 7th harmonic mapped voltage are converted into D-axis 7th harmonic voltage and Q-axis 7th harmonic voltage using a second inverse transformation matrix.

[0022] In one possible implementation, the step of extracting the D-axis higher harmonic mapping current and the Q-axis higher harmonic mapping current from the D-axis output current and the Q-axis output current respectively by transforming the matrix includes:

[0023] The initial higher harmonic mapping current of the D-axis and the initial higher harmonic mapping current of the Q-axis are extracted from the output current of the D-axis and the output current of the Q-axis, respectively, by means of the transformation matrix.

[0024] The initial higher harmonic mapping currents of the D-axis and the Q-axis are filtered by low-pass filters to obtain the higher harmonic mapping currents of the D-axis and the Q-axis.

[0025] In one possible implementation, determining the target D-axis voltage and target Q-axis voltage of the motor based on the target torque of the motor includes:

[0026] Based on the target torque of the motor, determine the target current of the motor on the D-axis and the target current of the motor on the Q-axis;

[0027] The D-axis target current and the Q-axis target current are integrated by a third proportional-integral controller to obtain the D-axis target voltage and the Q-axis target voltage.

[0028] In one possible implementation, determining the target D-axis current and target Q-axis current of the motor based on the target torque of the motor includes:

[0029] Based on the target torque of the motor, determine the initial target current of the motor's D-axis and the initial target current of its Q-axis;

[0030] The target current of the motor's D-axis is determined based on the initial target current of the D-axis and the output current of the D-axis.

[0031] The target current of the motor's Q-axis is determined based on the initial target current of the Q-axis and the output current of the Q-axis.

[0032] In one possible implementation, converting the D-axis input voltage and the Q-axis input voltage into the three-phase input voltage of the motor includes:

[0033] The D-axis input voltage and the Q-axis input voltage are converted into the α-axis input voltage and β-axis input voltage in the αβ coordinate system;

[0034] The α-axis input voltage and the β-axis input voltage are converted into the three-phase input voltage of the motor.

[0035] Secondly, embodiments of this application provide a motor control device, wherein the motor is a three-phase AC motor, and the device includes:

[0036] An output current conversion device is used to convert the three-phase current output by the motor into the D-axis output current and Q-axis output current of the motor. The D-axis is in the same direction as the magnetic flux of the motor rotor, and the Q-axis is perpendicular to the magnetic flux of the motor rotor.

[0037] A harmonic voltage determination device is used to determine the higher harmonic voltages of the D-axis and the Q-axis based on the D-axis output current and the Q-axis output current.

[0038] A target voltage determining device is used to determine the D-axis target voltage and Q-axis target voltage of the motor based on the target torque of the motor.

[0039] An input voltage determining device is used to calculate the difference between the D-axis target voltage and the D-axis higher harmonic voltage to obtain the D-axis input voltage of the motor; and to calculate the difference between the Q-axis target voltage and the Q-axis higher harmonic voltage to obtain the Q-axis input voltage of the motor.

[0040] An input voltage conversion device is used to convert the D-axis input voltage and the Q-axis input voltage into the three-phase input voltage of the motor.

[0041] Thirdly, embodiments of this application provide a vehicle, including:

[0042] An on-board controller configured to perform the method of any one of claims 1 to 7.

[0043] Fourthly, embodiments of this application provide a computer-readable storage medium, characterized in that the computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to perform the method described in any one of claims 1 to 7.

[0044] In this embodiment, the vehicle extracts high-order harmonic current from the motor's output current and determines high-order harmonic voltage based on this current. By removing the high-order harmonic voltage from the motor's target voltage, the motor's input voltage is determined, thereby significantly reducing high-order harmonics in the motor's input voltage. Since high-order harmonics are reduced as much as possible, the motor's harmonic torque is reduced, thus greatly improving the problem of motor torque ripple. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 is a schematic diagram of an application scenario provided by an embodiment of this application.

[0047] Figure 2 is a flowchart illustrating a motor control method provided in an embodiment of this application.

[0048] Figure 3 is a flowchart illustrating a three-phase current signal coordinate system transformation method provided in an embodiment of this application.

[0049] Figure 4 is a flowchart illustrating a method for determining higher harmonic voltages provided in an embodiment of this application.

[0050] Figure 5 is a flowchart illustrating a method for determining higher harmonic mapping current provided in an embodiment of this application.

[0051] Figure 6 is a flowchart illustrating a target voltage determination method provided in an embodiment of this application.

[0052] Figure 7 is a flowchart illustrating a target current determination method provided in an embodiment of this application.

[0053] Figure 8 is a schematic diagram of the structure of a motor control device provided in an embodiment of this application. Detailed Implementation

[0054] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0055] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0056] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0057] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0058] To facilitate understanding, specific application scenarios are illustrated below.

[0059] Referring to Figure 1, an application scenario diagram is provided for an embodiment of this application. As shown in Figure 1, the vehicle 100 includes a controller 101, a motor 102, and an inverter 103. Specifically, the vehicle 100 controls the inverter 103 through the controller 101 to convert DC power into AC power to supply power to the motor 102.

[0060] Vehicle 100 is a new energy vehicle, which can be a pure electric vehicle or a hybrid vehicle.

[0061] Motor 102 is a three-phase AC motor capable of outputting torque according to the input voltage determined by controller 101. Motor 102 can be a permanent magnet synchronous motor, an induction synchronous motor, an electrically excited synchronous motor, etc., and this application embodiment does not impose specific limitations on it.

[0062] Inverter 103 is typically composed of an inverter circuit, which is generally composed of power semiconductor devices (Insulated Gate Bipolar Transistors, IGBTs). During the inverter process, to prevent short circuits, the control signals usually require a dead time, ensuring that the IGBTs used for inversion are simultaneously turned off. Each inverter cycle has a dead time, and each IGBT turn-on requires a certain on-state voltage drop. Due to the high switching frequency of the IGBTs, there are numerous inverter cycles per unit time. The combined effects of the dead time and the on-state voltage drop cause high-order harmonics in the motor's input voltage. Vehicle 100 can suppress these high-order harmonics using controller 101 to determine the input voltage of motor 102.

[0063] Furthermore, the vehicle structure shown in Figure 1 is merely an exemplary description and should not be construed as a limitation on the scope of protection of this application.

[0064] In related technologies, the impact of higher harmonics on the motor is generally reduced by adjusting the dead time of the IGBT in the inverter. Although this solution can reduce higher harmonics, the dead time of the IGBT still exists, causing the motor to still generate harmonic torque, thus causing torque pulsation in the motor.

[0065] To address the aforementioned issues, in this embodiment, the vehicle extracts high-order harmonic current from the motor's output current, determines high-order harmonic voltage based on the high-order harmonic current, and suppresses high-order harmonics by removing the high-order harmonic voltage from the motor's target voltage. By minimizing high-order harmonics, the motor's harmonic torque is reduced, thereby mitigating the problem of motor torque ripple.

[0066] Specifically, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments.

[0067] Referring to Figure 2, a flowchart illustrating a motor control method provided in this application embodiment is shown. This method can be applied to the controller in the application scenario shown in Figure 1. As shown in Figure 2, it mainly includes the following steps.

[0068] Step S201: Convert the three-phase current output by the motor into the D-axis output current and Q-axis output current of the motor.

[0069] Referring to Figure 3, a flowchart illustrating a three-phase current signal coordinate system transformation method provided in this application embodiment is shown. As shown in Figure 3, it mainly includes the following steps.

[0070] Step S301: Obtain the three-phase current of the motor.

[0071] The controller obtains the three-phase current i of the motor. a ib i c The three phases are 120° apart, and the waveform of each current signal changing over time is ideally a sine wave. The three-phase current of the motor is usually the current on the stator.

[0072] Step S302: Transform the three-phase current signal to the αβ coordinate system.

[0073] The three-phase current signal i is transformed using Clerk transformation. a i b i c Transform to the αβ coordinate system. In the αβ coordinate system, the current components i on the α and β axes... α i β The phase difference between them is 90 degrees, i α i β The waveform changes over time, ideally a sine wave.

[0074] Step S303: Transform the current signal from the αβ coordinate system to the DQ coordinate system.

[0075] The Park transform converts the current signal from the αβ coordinate system to the DQ coordinate system. The DQ coordinate system is a synchronously rotating orthogonal coordinate system where the D-axis aligns with the magnetic flux direction of the motor rotor, the Q-axis is perpendicular to the magnetic flux direction of the motor rotor, and the Q-axis leads the D-axis by 90°. That is, the D-axis and Q-axis are perpendicular and rotate synchronously with the magnetic flux direction of the motor rotor. In the DQ coordinate system, the current components on the D-axis and Q-axis—that is, the D-axis output current and the Q-axis output current—ideally have two constant values.

[0076] By using Clerk and Park transformations, the three-phase current signals of the motor are transformed into the DQ coordinate system, and the three-phase currents on the stator are equivalent to the D-axis and Q-axis, which simplifies the analysis of motor operation.

[0077] Step S202: Determine the higher harmonic voltages of the D-axis and Q-axis based on the D-axis output current and the Q-axis output current.

[0078] Referring to Figure 4, a flowchart illustrating a method for determining higher harmonic voltages according to an embodiment of this application is provided. As shown in Figure 4, it mainly includes the following steps.

[0079] Step S401: Extract the D-axis higher harmonic mapping current and the Q-axis higher harmonic mapping current from the D-axis output current and the Q-axis output current respectively by transforming the matrix.

[0080] In this embodiment, the transformation matrix refers to the synchronous rotation transformation matrix used when extracting higher harmonics from the first DQ coordinate system into the second DQ coordinate system through synchronous rotation transformation. Specifically, the D-axis and Q-axis of the first DQ coordinate system are aligned with and synchronously rotated to the direction of the magnetic field generating the output current; similarly, the D-axis and Q-axis of the second DQ coordinate system are aligned with and synchronously rotated to the direction of the magnetic field generating the higher harmonic current.

[0081] To further understand, in the first DQ coordinate system, the components of the motor's output current along the D and Q axes are constant values. However, in the first DQ coordinate system, the rotational speeds of the D and Q axes are not the same as the rotational speed of the magnetic field that generates the higher harmonic current. Therefore, the D-axis and Q-axis components of the higher harmonic current in the first DQ coordinate system are not constant values. For ease of analysis, it is necessary to transform the higher harmonic current to the second DQ coordinate system. In the second DQ coordinate system, the components of the higher harmonic current along the D and Q axes are constant values. Therefore, the matrix used to transform the higher harmonic current from the first DQ coordinate system to the second DQ coordinate system is the transformation matrix.

[0082] In one possible implementation, the higher harmonic mapping currents of the D-axis and Q-axis are extracted from the output currents of the D-axis and Q-axis respectively by means of a transformation matrix.

[0083] By using a transformation matrix, the higher harmonic current is transformed to the second DQ coordinate system. In the second DQ coordinate system, the D-axis and Q-axis components of the higher harmonic current are constant values, allowing for the extraction of the higher harmonic current. In this embodiment, the D-axis and Q-axis components of the higher harmonic current in the second DQ coordinate system are respectively referred to as the D-axis higher harmonic mapped current, and the Q-axis component is referred to as the Q-axis higher harmonic mapped current.

[0084] In one possible implementation, the 5th harmonic mapping current of the D-axis and the 5th harmonic mapping current of the Q-axis are extracted from the D-axis output current and the Q-axis output current, respectively, by means of a first transformation matrix.

[0085] The first transformation matrix is ​​shown in matrix (1):

[0086] Where θ refers to the angle between the α axis and the D axis.

[0087] The first transformation matrix is ​​a synchronous rotation transformation matrix used to transform the 5th harmonic current to the third DQ coordinate system. In this system, the D-axis and Q-axis are aligned with and synchronously rotated with the magnetic field that generates the 5th harmonic current. The D-axis and Q-axis components of the 5th harmonic current are constant values ​​in the third DQ coordinate system, allowing for the extraction of the 5th harmonic current. In this embodiment, the D-axis and Q-axis components of the 5th harmonic current in the third DQ coordinate system are referred to as the D-axis 5th harmonic mapped current and the Q-axis 5th harmonic mapped current, respectively.

[0088] In one possible implementation, the 7th harmonic mapping current of the D-axis and the 7th harmonic mapping current of the Q-axis are extracted from the D-axis output current and the Q-axis output current, respectively, by means of a second transformation matrix.

[0089] The second transformation matrix is ​​shown in matrix (2):

[0090] Where θ refers to the angle between the α axis and the D axis.

[0091] The second transformation matrix is ​​a synchronous rotation transformation matrix used to transform the 7th harmonic current to the fourth DQ coordinate system. In this system, the D-axis and Q-axis are aligned with and synchronously rotated with the magnetic field that generates the 7th harmonic current. The D-axis and Q-axis components of the 7th harmonic current are constant values ​​in the fourth DQ coordinate system, allowing for the extraction of the 7th harmonic current. In this embodiment, the D-axis and Q-axis components of the 7th harmonic current in the fourth DQ coordinate system are referred to as the D-axis 7th harmonic mapped current and the Q-axis 7th harmonic mapped current, respectively.

[0092] In one possible implementation, the 5th harmonic mapping current of the D-axis and the 5th harmonic mapping current of the Q-axis can be extracted from the D-axis output current and the Q-axis output current respectively using a first transformation matrix, and the 7th harmonic mapping current of the D-axis and the 7th harmonic mapping current of the Q-axis can be extracted from the D-axis output current and the Q-axis output current respectively using a second transformation matrix.

[0093] Referring to Figure 5, a flowchart illustrating a method for determining higher harmonic mapping currents according to an embodiment of this application is provided. As shown in Figure 5, it mainly includes the following steps.

[0094] Step S501: Extract the initial high-order harmonic mapping current of the D-axis and the initial high-order harmonic mapping current of the Q-axis from the D-axis output current and the Q-axis output current respectively by transforming the matrix.

[0095] In practical applications, due to the influence of nonlinear loads (such as frequency converters and rectifiers), noise may be present in the D-axis and Q-axis higher harmonic mapping currents extracted from the D-axis and Q-axis output currents respectively through the transformation matrix. In the second DQ coordinate system, the D-axis and Q-axis higher harmonic mapping currents should theoretically be constant values. However, due to the presence of noise, the waveforms of these currents fluctuate.

[0096] In this embodiment, the higher harmonic mapping currents along the D-axis and Q-axis, which may contain noise in the second DQ coordinate system, are referred to as the initial higher harmonic mapping current along the D-axis and the initial higher harmonic mapping current along the Q-axis, respectively. To improve the accuracy of the higher harmonic mapping currents along the D-axis and Q-axis, noise reduction processing is required for both.

[0097] Step S502: Filter the initial high-order harmonic mapping current of the D-axis and the initial high-order harmonic mapping current of the Q-axis using a low-pass filter to obtain the high-order harmonic mapping current of the D-axis and the high-order harmonic mapping current of the Q-axis.

[0098] In one possible implementation, the initial higher harmonic mapping currents of the D-axis and Q-axis are filtered by low-pass filters to obtain the higher harmonic mapping currents of the D-axis and Q-axis, thereby improving the accuracy of the higher harmonic mapping currents of the D-axis and Q-axis.

[0099] Step S402: Integrate the D-axis high harmonic mapping current and the Q-axis high harmonic mapping current respectively using a proportional-integral controller to obtain the D-axis high harmonic mapping voltage and the Q-axis high harmonic mapping voltage.

[0100] It should be noted that the process of obtaining the D-axis higher harmonic mapping voltage and the Q-axis higher harmonic mapping voltage is carried out in the second DQ coordinate system.

[0101] In one possible implementation, the fifth harmonic mapping current of the D-axis and the fifth harmonic mapping current of the Q-axis are integrated by a first proportional-integral controller to obtain the fifth harmonic mapping voltage of the D-axis and the fifth harmonic mapping voltage of the Q-axis.

[0102] It should be noted that the process of obtaining the 5th harmonic mapped voltage on the D-axis and the 5th harmonic mapped voltage on the Q-axis is carried out in the third DQ coordinate system.

[0103] In one possible implementation, the 7th harmonic mapped current of the D-axis and the 7th harmonic mapped current of the Q-axis are integrated by a second proportional-integral controller to obtain the 7th harmonic mapped voltage of the D-axis and the 7th harmonic mapped voltage of the Q-axis.

[0104] It should be noted that the process of obtaining the 7th harmonic mapped voltage on the D-axis and the 7th harmonic mapped voltage on the Q-axis is carried out in the fourth DQ coordinate system.

[0105] In one possible implementation, the 5th harmonic mapped current along the D-axis and the 5th harmonic mapped current along the Q-axis can be integrated in the third DQ coordinate system using a first proportional-integral controller to obtain the 5th harmonic mapped voltage along the D-axis and the 5th harmonic mapped voltage along the Q-axis. Alternatively, the 7th harmonic mapped current along the D-axis and the 7th harmonic mapped current along the Q-axis can be integrated in the fourth DQ coordinate system using a second proportional-integral controller to obtain the 7th harmonic mapped voltage along the D-axis and the 7th harmonic mapped current along the Q-axis.

[0106] Step S403: Convert the D-axis higher harmonic mapping voltage and the Q-axis higher harmonic mapping voltage into D-axis higher harmonic voltage and Q-axis higher harmonic voltage using the inverse transformation matrix.

[0107] In this embodiment, the inverse transformation matrix is ​​the synchronous rotation transformation matrix used when transforming the higher harmonic voltage from the second DQ coordinate system to the first DQ coordinate system through synchronous rotation.

[0108] By using the inverse transformation matrix, the higher harmonic mapping voltages of the D-axis and Q-axis can be transformed from the second DQ coordinate system to the first DQ coordinate system, thereby obtaining the higher harmonic voltages of the D-axis and Q-axis in the first DQ coordinate system.

[0109] In one possible implementation, the D-axis 5th harmonic mapped voltage and the Q-axis 5th harmonic mapped voltage are converted into the D-axis 5th harmonic voltage and the Q-axis 5th harmonic voltage through a first inverse transformation matrix.

[0110] The first inverse transformation matrix is ​​shown in matrix (3):

[0111] Where θ refers to the angle between the α axis and the D axis.

[0112] The first inverse transformation matrix is ​​a synchronous rotation transformation matrix used to transform the 5th harmonic mapped voltage from the third DQ coordinate system to the first DQ coordinate system. Through the first inverse transformation matrix, the 5th harmonic mapped voltage along the D-axis and the 5th harmonic mapped voltage along the Q-axis can be transformed from the third DQ coordinate system to the first DQ coordinate system, thus obtaining the 5th harmonic voltage along the D-axis and the 5th harmonic voltage along the Q-axis in the first DQ coordinate system.

[0113] In one possible implementation, the D-axis 7th harmonic mapped voltage and the Q-axis 7th harmonic mapped voltage are converted into the D-axis 7th harmonic voltage and the Q-axis 7th harmonic voltage through a second inverse transformation matrix.

[0114] The second inverse transformation matrix is ​​shown in matrix (4):

[0115] Where θ refers to the angle between the α axis and the D axis.

[0116] The second inverse transformation matrix is ​​a synchronous rotation transformation matrix used to transform the 7th harmonic mapped voltage from the fourth DQ coordinate system to the first DQ coordinate system. Through the second inverse transformation matrix, the 7th harmonic mapped voltage along the D-axis and the 7th harmonic mapped voltage along the Q-axis can be transformed from the fourth DQ coordinate system to the first DQ coordinate system, thus allowing the 7th harmonic voltage along the D-axis and the 7th harmonic voltage along the Q-axis to be obtained in the first DQ coordinate system.

[0117] In one possible implementation, the 5th harmonic mapping voltage of the D-axis and the 5th harmonic mapping voltage of the Q-axis can be converted into the 5th harmonic voltage of the D-axis and the 5th harmonic voltage of the Q-axis using a first inverse transformation matrix, and the 7th harmonic mapping voltage of the D-axis and the 7th harmonic mapping voltage of the Q-axis can be converted into the 7th harmonic voltage of the D-axis and the 7th harmonic voltage of the Q-axis using a second inverse transformation matrix.

[0118] In practical applications, higher harmonics above the 7th order, such as the 9th, 11th, and 13th harmonics, have minimal impact on the torque ripple problem of motors. Suppressing all higher harmonics above the 7th order would require a large investment in equipment, which is not cost-effective. Therefore, in this embodiment, the suppression mainly targets the 5th and 7th harmonics.

[0119] Step S203: Determine the target voltage of the motor's D-axis and Q-axis based on the motor's target torque.

[0120] Referring to Figure 6, a flowchart illustrating a target voltage determination method provided in this application embodiment is shown. As shown in Figure 6, it mainly includes the following steps.

[0121] Step S601: Determine the target current of the motor's D-axis and Q-axis based on the target torque of the motor.

[0122] In practical applications, due to the influence of nonlinear loads, there is an error fluctuation between the actual output current of the motor and the target current, which affects the torque output of the motor. Therefore, it is necessary to control the error between the actual output current and the target current of the motor.

[0123] Referring to Figure 7, a flowchart illustrating a target current determination method provided in an embodiment of this application is shown. As illustrated in Figure 7, it mainly includes the following steps.

[0124] Step S701: Determine the initial target current of the motor's D-axis and Q-axis based on the motor's target torque.

[0125] The initial target currents for the D-axis and Q-axis are theoretical values ​​determined based on the target torque of the motor. The goal is to obtain the target output by inputting these values ​​to the motor. In practical applications, due to factors such as nonlinear loads, there is an error between the actual output and the target output value of the motor. Therefore, it is necessary to control the error between the actual output and the target output of the motor.

[0126] In one possible implementation, a negative feedback control method is used to control the motor output.

[0127] Negative feedback refers to adjusting the motor's output based on the error between the initial target current and the output current of the motor's D-axis, and the error between the initial target current and the output current of the Q-axis, so that the motor's output changes according to the given input, and the motor's output gradually approaches the target output.

[0128] Step S702: Determine the target current of the motor's D-axis based on the initial target current of the D-axis and the output current of the D-axis.

[0129] The target current of the motor's D-axis is determined based on the difference between the initial target current of the D-axis and the output current of the D-axis, as well as the initial target current of the D-axis.

[0130] Step S703: Determine the target current of the motor's Q-axis based on the initial target current of the Q-axis and the output current of the Q-axis.

[0131] The target current of the motor's Q-axis is determined based on the difference between the initial target current of the Q-axis and the output current of the Q-axis, as well as the initial target current of the Q-axis.

[0132] Step S602: Integrate the D-axis target current and the Q-axis target current respectively using the third proportional-integral controller to obtain the D-axis target voltage and the Q-axis target voltage.

[0133] Through steps S601-S602, the target voltage of the D-axis and the target voltage of the Q-axis can be obtained based on the target torque of the motor.

[0134] Step S204: Calculate the difference between the D-axis target voltage and the D-axis higher harmonic voltage to obtain the D-axis input voltage of the motor; calculate the difference between the Q-axis target voltage and the Q-axis higher harmonic voltage to obtain the Q-axis input voltage of the motor.

[0135] By subtracting the values, the higher harmonic voltages of the D-axis and Q-axis are removed from the target voltages of the D-axis and Q-axis, respectively, thereby achieving the purpose of suppressing higher harmonics.

[0136] For example, if the three-phase input voltage of the motor is 380V, but due to the influence of higher harmonics generated during the inverter process, the three-phase input voltage of the motor is 390V, then the higher harmonic voltage is 10V. To suppress the higher harmonic voltage, the higher harmonic voltage is extracted into the first DQ coordinate system, and the target three-phase input voltage of the motor, 380V, is also transformed into the first DQ coordinate system. In the first DQ coordinate system, the difference between the D-axis target voltage and the D-axis higher harmonic voltage is calculated to obtain the D-axis input voltage of the motor; the difference between the Q-axis target voltage and the Q-axis higher harmonic voltage is calculated to obtain the Q-axis input voltage of the motor. At this time, the D-axis input voltage and Q-axis input voltage are transformed into a three-phase input voltage of 370V for the motor. Then, the three-phase input voltage of the motor passes through the inverter circuit in the inverter. During the inverter process, higher harmonics are generated again. Affected by the higher harmonics, the actual three-phase input voltage of the motor is 380V, thereby achieving the purpose of suppressing higher harmonics.

[0137] Step S205: Convert the D-axis input voltage and Q-axis input voltage into the three-phase input voltage of the motor.

[0138] First, the D-axis and Q-axis input voltages are transformed into the αβ coordinate system using the Park inverse transformation. Second, the α-axis and β-axis input voltages in the αβ coordinate system are converted into three-phase drive signals for the inverter circuit using a space vector pulse width modulation algorithm. Then, the IGBTs in the inverter circuit are driven by these three-phase drive signals to convert DC power into three-phase input voltages for the motor.

[0139] Corresponding to the above method embodiments, this application also provides a motor control device. Specifically, referring to FIG8, it is a structural schematic diagram of a motor control device provided in an embodiment of this application. As shown in FIG8, the motor control device 800 is shown in the figure. The motor control device 800 includes: an output current conversion device 801, a harmonic voltage determination device 802, a target voltage determination device 803, an input voltage determination device 804, and an input voltage conversion device 805. Specifically, the output current conversion device 801 is used to convert the three-phase current output by the motor into the D-axis output current and Q-axis output current of the motor, wherein the magnetic flux direction of the D-axis is the same as that of the rotor of the motor, and the magnetic flux direction of the Q-axis is perpendicular to that of the rotor of the motor; the harmonic voltage determination device 802 is used to determine the higher harmonic voltages of the D-axis and Q-axis based on the D-axis output current and the Q-axis output current; the target voltage determination device 803 is used to determine the target voltage of the D-axis and the target voltage of the Q-axis of the motor based on the target torque of the motor; the input voltage determination device 804 is used to calculate the difference between the target voltage of the D-axis and the higher harmonic voltage of the D-axis to obtain the D-axis input voltage of the motor; and to calculate the difference between the target voltage of the Q-axis and the higher harmonic voltage of the Q-axis to obtain the Q-axis input voltage of the motor; the input voltage conversion device 805 is used to convert the D-axis input voltage and the Q-axis input voltage into the three-phase input voltage of the motor.

[0140] For details regarding the specific content involved in the embodiments of this application, please refer to the description of the above method embodiments. For the sake of brevity, these details will not be repeated here.

[0141] Corresponding to the above method embodiments, this application also provides a vehicle. Specifically, the vehicle includes a controller for executing some or all of the steps described in the above method embodiments; for the sake of brevity, these will not be elaborated further.

[0142] Corresponding to the above method embodiments, this application also provides a computer storage medium, wherein the computer storage medium may store a program, which, when executed, may include some or all of the steps in the various embodiments of the simulation scene generation method provided by this invention. The storage medium may be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0143] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, the simultaneous existence of A and B, or the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0144] Those skilled in the art will recognize that the units and algorithm steps described in the embodiments disclosed herein can be implemented using electronic hardware, computer software, or a combination of electronic hardware and software. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0145] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0146] In the several embodiments provided in this application, any function, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0147] The same or similar parts between the various embodiments in this specification can be referred to mutually. In particular, the device embodiments and terminal embodiments are basically similar to the method embodiments, so the description is relatively simple, and the relevant parts can be referred to the description in the method embodiments.

Claims

1. A motor control method, characterized in that, The motor is a three-phase AC motor, and the method includes: The three-phase current output by the motor is converted into the D-axis output current and Q-axis output current of the motor. The D-axis is in the same direction as the magnetic flux of the motor rotor, and the Q-axis is perpendicular to the magnetic flux of the motor rotor. The higher harmonic voltages of the D-axis and Q-axis are determined based on the D-axis output current and the Q-axis output current. Based on the target torque of the motor, determine the target voltage of the motor on the D-axis and the target voltage on the Q-axis; The difference between the D-axis target voltage and the D-axis higher harmonic voltage is calculated to obtain the D-axis input voltage of the motor; the difference between the Q-axis target voltage and the Q-axis higher harmonic voltage is calculated to obtain the Q-axis input voltage of the motor. The D-axis input voltage and the Q-axis input voltage are converted into the three-phase input voltage of the motor.

2. The method according to claim 1, characterized in that, The step of determining the D-axis higher harmonic voltage and the Q-axis higher harmonic voltage based on the D-axis output current and the Q-axis output current includes: The higher harmonic mapping currents of the D-axis and Q-axis are extracted from the output current of the D-axis and the output current of the Q-axis respectively by the transformation matrix. The higher harmonic mapping current of the D-axis and the higher harmonic mapping current of the Q-axis are integrated by a proportional-integral controller to obtain the higher harmonic mapping voltage of the D-axis and the higher harmonic mapping voltage of the Q-axis. The D-axis higher harmonic mapping voltage and the Q-axis higher harmonic mapping voltage are converted into D-axis higher harmonic voltage and Q-axis higher harmonic voltage using an inverse transformation matrix.

3. The method according to claim 2, characterized in that, The step of determining the D-axis higher harmonic voltage and the Q-axis higher harmonic voltage based on the D-axis output current and the Q-axis output current includes: The 5th harmonic mapping current of the D-axis and the 5th harmonic mapping current of the Q-axis are extracted from the D-axis output current and the Q-axis output current respectively using the first transformation matrix; and / or, the 7th harmonic mapping current of the D-axis and the 7th harmonic mapping current of the Q-axis are extracted from the D-axis output current and the Q-axis output current respectively using the second transformation matrix; The 5th harmonic mapping current along the D-axis and the 5th harmonic mapping current along the Q-axis are integrated by a first proportional-integral controller to obtain the 5th harmonic mapping voltage along the D-axis and the 5th harmonic mapping voltage along the Q-axis; and / or, the 7th harmonic mapping current along the D-axis and the 7th harmonic mapping current along the Q-axis are integrated by a second proportional-integral controller to obtain the 7th harmonic mapping voltage along the D-axis and the 7th harmonic mapping voltage along the Q-axis. The D-axis 5th harmonic mapped voltage and the Q-axis 5th harmonic mapped voltage are converted into D-axis 5th harmonic voltage and Q-axis 5th harmonic voltage using a first inverse transformation matrix; and / or, the D-axis 7th harmonic mapped voltage and the Q-axis 7th harmonic mapped voltage are converted into D-axis 7th harmonic voltage and Q-axis 7th harmonic voltage using a second inverse transformation matrix.

4. The method according to claim 2, characterized in that, The step of extracting the D-axis higher harmonic mapping current and the Q-axis higher harmonic mapping current from the D-axis output current and the Q-axis output current respectively by transforming the matrix includes: The initial higher harmonic mapping current of the D-axis and the initial higher harmonic mapping current of the Q-axis are extracted from the output current of the D-axis and the output current of the Q-axis, respectively, by means of the transformation matrix. The initial higher harmonic mapping currents of the D-axis and the Q-axis are filtered by low-pass filters to obtain the higher harmonic mapping currents of the D-axis and the Q-axis.

5. The method according to claim 1, characterized in that, The step of determining the target voltage of the motor's D-axis and Q-axis based on the motor's target torque includes: Based on the target torque of the motor, determine the target current of the motor on the D-axis and the target current of the motor on the Q-axis; The D-axis target current and the Q-axis target current are integrated by a third proportional-integral controller to obtain the D-axis target voltage and the Q-axis target voltage.

6. The method according to claim 5, characterized in that, The step of determining the target D-axis current and target Q-axis current of the motor based on the target torque of the motor includes: Based on the target torque of the motor, determine the initial target current of the motor's D-axis and the initial target current of its Q-axis; The target current of the motor's D-axis is determined based on the initial target current of the D-axis and the output current of the D-axis. The target current of the motor's Q-axis is determined based on the initial target current of the Q-axis and the output current of the Q-axis.

7. The method according to claim 1, characterized in that, The step of converting the D-axis input voltage and the Q-axis input voltage into the three-phase input voltage of the motor includes: The D-axis input voltage and the Q-axis input voltage are converted into the α-axis input voltage and β-axis input voltage in the αβ coordinate system; The α-axis input voltage and the β-axis input voltage are converted into the three-phase input voltage of the motor.

8. A motor control device, characterized in that, The motor is a three-phase AC motor, and the device includes: An output current conversion device is used to convert the three-phase current output by the motor into the D-axis output current and Q-axis output current of the motor. The D-axis is in the same direction as the magnetic flux of the motor rotor, and the Q-axis is perpendicular to the magnetic flux of the motor rotor. A harmonic voltage determination device is used to determine the higher harmonic voltages of the D-axis and the Q-axis based on the D-axis output current and the Q-axis output current. A target voltage determining device is used to determine the D-axis target voltage and Q-axis target voltage of the motor based on the target torque of the motor. An input voltage determining device is used to calculate the difference between the D-axis target voltage and the D-axis higher harmonic voltage to obtain the D-axis input voltage of the motor; and to calculate the difference between the Q-axis target voltage and the Q-axis higher harmonic voltage to obtain the Q-axis input voltage of the motor. An input voltage conversion device is used to convert the D-axis input voltage and the Q-axis input voltage into the three-phase input voltage of the motor.

9. A vehicle, characterized in that, include: A controller configured to perform the method of any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the method according to any one of claims 1 to 7.

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