Motor control method and device, vehicle and storage medium

Abstract

The embodiment of the invention discloses a motor control method and device, a vehicle and a storage medium. The method comprises the steps that three-phase current output by a motor is converted into D-axis output current and Q-axis output current of the motor; determining a D-axis higher harmonic voltage and a Q-axis higher harmonic voltage according to the D-axis output current and the Q-axis output current; determining a D-axis target voltage and a Q-axis target voltage of the motor according to the target torque of the motor; performing difference calculation on the D-axis target voltage and the D-axis higher harmonic voltage to obtain a D-axis input voltage of the motor; performing difference calculation on the Q-axis target voltage and the Q-axis higher harmonic voltage to obtain 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 voltage of the motor. It can be understood that the higher harmonic voltage is removed from the target voltage of the motor, and the higher harmonic is weakened, so that the harmonic torque of the motor is weakened, and the problem of torque pulsation of the motor is greatly improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and specifically to a motor control method, device, vehicle and storage medium. Background Art

[0002] New energy vehicles (also referred to as "vehicles" in this article) usually include motors and power batteries, among which motors generally use three-phase AC motors. Since power batteries usually output DC power, and motors need to input three-phase AC power, vehicles generally need to convert DC power into AC power, a process called inversion. Vehicles generally achieve inversion through inverters. Inverters are usually composed of inverter circuits, and inverter circuits are generally composed of power semiconductor devices (Insulated Gate Bipolar Transistor, IGBT).

[0003] During the inversion process, in order to avoid short circuit of the inverter, the signal controlling the inversion usually needs to set a dead time so that the IGBTs used for inversion in the inverter are disconnected at the same time. There is a dead time for each inversion cycle, and each time the IGBT is turned on, a certain conduction voltage drop is required. Since the switching frequency of the IGBT is high, there are a large number of inversion cycles per unit time. Then, after the effects of the dead time and the conduction voltage drop are superimposed, the input voltage of the motor generates high-order harmonics. High-order harmonics may cause the motor to generate harmonic torque, which in turn causes the motor torque pulsation. Therefore, high-order harmonics should be suppressed.

[0004] In the related art, the influence of high-order harmonics on the motor is generally weakened by adjusting the dead time of the IGBT in the inverter. Although this solution can weaken the high-order harmonics, the dead time of the IGBT still exists, so that the motor still generates harmonic torque, thereby causing the motor torque pulsation phenomenon.

[0005] It should be pointed out that the information disclosed in the background technology section of this application is only intended to deepen the understanding of the general background technology of this application, and should not be regarded as an admission or suggestion in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention

[0006] In view of this, the present application provides a motor control method, device, vehicle and storage medium, so as to solve the problem that when the vehicle converts direct current into alternating current, i.e., inversion, due to the dead time and conduction voltage drop of the IGBT in the inverter, high-order harmonics exist in the input voltage of the motor, causing harmonic torque and thus causing motor torque pulsation.

[0007] In a first aspect, an embodiment of the present application provides a motor control method, wherein the motor is a three-phase AC motor, and the method includes: Converting the three-phase current output by the motor into a D-axis output current and a Q-axis output current of the motor, wherein the D-axis has the same direction as the magnetic flux of the rotor of the motor, and the Q-axis is perpendicular to the magnetic flux of the rotor of the motor; Determining a D-axis high-order harmonic voltage and a Q-axis high-order harmonic voltage according to the D-axis output current and the Q-axis output current; Determining a D-axis target voltage and a Q-axis target voltage of the motor according to a target torque of the motor; The D-axis target voltage and the D-axis high-order harmonic voltage are calculated to obtain the D-axis input voltage of the motor; the Q-axis target voltage and the Q-axis high-order harmonic voltage are 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 a three-phase input voltage of the motor.

[0008] In a possible implementation, determining the D-axis high-order harmonic voltage and the Q-axis high-order harmonic voltage according to the D-axis output current and the Q-axis output current includes: Extracting a D-axis high-order harmonic mapping current and a Q-axis high-order harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a transformation matrix; The D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current are respectively integrated by a proportional-integral controller to obtain a D-axis high-order harmonic mapping voltage and a Q-axis high-order harmonic mapping voltage; The D-axis high-order harmonic mapping voltage and the Q-axis high-order harmonic mapping voltage are converted into a D-axis high-order harmonic voltage and a Q-axis high-order harmonic voltage through an inverse transformation matrix.

[0009] In a possible implementation, determining the D-axis high-order harmonic voltage and the Q-axis high-order harmonic voltage according to the D-axis output current and the Q-axis output current includes: Extracting the D-axis 5th harmonic mapping current and the Q-axis 5th harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a first transformation matrix; and / or extracting the D-axis 7th harmonic mapping current and the Q-axis 7th harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a second transformation matrix; The D-axis 5th harmonic mapping current and the Q-axis 5th harmonic mapping current are respectively integrated by a first proportional-integral controller to obtain a D-axis 5th harmonic mapping voltage and a Q-axis 5th harmonic mapping voltage; and / or, the D-axis 7th harmonic mapping current and the Q-axis 7th harmonic mapping current are respectively integrated by a second proportional-integral controller to obtain a D-axis 7th harmonic mapping voltage and a Q-axis 7th harmonic mapping voltage; The D-axis 5th harmonic mapping voltage and the Q-axis 5th harmonic mapping voltage are converted into the D-axis 5th harmonic voltage and the Q-axis 5th harmonic voltage through a first inverse transformation matrix; and / or, the D-axis 7th harmonic mapping voltage and the Q-axis 7th harmonic mapping voltage are converted into the D-axis 7th harmonic voltage and the Q-axis 7th harmonic voltage through a second inverse transformation matrix.

[0010] In a possible implementation, extracting a D-axis high-order harmonic mapping current and a Q-axis high-order harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a transformation matrix includes: Extracting a D-axis initial high-order harmonic mapping current and a Q-axis initial high-order harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a transformation matrix; The D-axis initial high-order harmonic mapping current and the Q-axis initial high-order harmonic mapping current are filtered respectively by a low-pass filter to obtain a D-axis high-order harmonic mapping current and a Q-axis high-order harmonic mapping current.

[0011] In a possible implementation, determining a D-axis target voltage and a Q-axis target voltage of the motor according to the target torque of the motor includes: Determining a D-axis target current and a Q-axis target current of the motor according to a target torque of the motor; The D-axis target current and the Q-axis target current are respectively integrated by a third proportional-integral controller to obtain a D-axis target voltage and a Q-axis target voltage.

[0012] In a possible implementation, determining a D-axis target current and a Q-axis target current of the motor according to the target torque of the motor includes: Determining an initial target current of a D axis and an initial target current of a Q axis of the motor according to a target torque of the motor; Determining a D-axis target current of the motor according to the D-axis initial target current and the D-axis output current; The Q-axis target current of the motor is determined according to the Q-axis initial target current and the Q-axis output current.

[0013] In a possible implementation, converting the D-axis input voltage and the Q-axis input voltage into a three-phase input voltage of the motor includes: Converting the D-axis input voltage and the Q-axis input voltage into an α-axis input voltage and a β-axis input voltage in an αβ coordinate system; The α-axis input voltage and the β-axis input voltage are converted into a three-phase input voltage of the motor.

[0014] In a second aspect, an embodiment of the present application provides a motor control device, wherein the motor is a three-phase AC motor, and the device comprises: An output current conversion device, used for converting the three-phase current output by the motor into a D-axis output current and a Q-axis output current of the motor, wherein the D-axis has the same direction as the magnetic flux of the rotor of the motor, and the Q-axis is perpendicular to the magnetic flux of the rotor of the motor; A harmonic voltage determining device, used for determining a D-axis high-order harmonic voltage and a Q-axis high-order harmonic voltage according to the D-axis output current and the Q-axis output current; a target voltage determination device, for determining a D-axis target voltage and a Q-axis target voltage of the motor according to a target torque of the motor; An input voltage determination device, used for performing a difference calculation between the D-axis target voltage and the D-axis higher harmonic voltage to obtain the D-axis input voltage of the motor; performing a difference calculation 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 a three-phase input voltage of the motor.

[0015] In a third aspect, an embodiment of the present application provides a vehicle, including: An on-board controller, wherein the on-board controller is configured to execute the method according to any one of claims 1 to 7.

[0016] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, characterized in that the computer-readable storage medium includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute any one of the methods described in claims 1 to 7.

[0017] In the embodiment of the present application, the vehicle extracts high-order harmonic current from the output current of the motor, and determines the high-order harmonic voltage according to the high-order harmonic current. The input voltage of the motor is determined by removing the high-order harmonic voltage from the target voltage of the motor, thereby greatly weakening the high-order harmonics in the input voltage of the motor. Since the high-order harmonics are weakened as much as possible, the harmonic torque of the motor is weakened, thereby greatly improving the problem of motor torque pulsation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 A schematic diagram of an application scenario provided for an embodiment of the present application.

[0020] Figure 2 A schematic flow chart of a motor control method provided in an embodiment of the present application.

[0021] Figure 3 A schematic flow chart of a three-phase current signal coordinate system transformation method provided in an embodiment of the present application.

[0022] Figure 4 A schematic flow chart of a method for determining a high-order harmonic voltage provided in an embodiment of the present application.

[0023] Figure 5 A flowchart of a method for determining a high-order harmonic mapping current provided in an embodiment of the present application.

[0024] Figure 6 A schematic flow chart of a method for determining a target voltage provided in an embodiment of the present application.

[0025] Figure 7 A flowchart of a method for determining a target current provided in an embodiment of the present application.

[0026] Figure 8 A schematic diagram of the structure of a motor control device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0028] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0029] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0030] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0031] For ease of understanding, a specific application scenario is exemplified below.

[0032] See also Figure 1 , which provides a schematic diagram of an application scenario for the embodiment of the present application. Figure 1 As shown, 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 invert direct current into alternating current to supply power to the motor 102.

[0033] The vehicle 100 is a new energy vehicle, which may be a pure electric vehicle or a hybrid vehicle.

[0034] The motor 102 is a three-phase AC motor that can output torque according to the input voltage determined by the controller 101. The motor 102 can be a permanent magnet synchronous motor, an induction synchronous motor, an electrically excited synchronous motor, etc., and the embodiment of the present application does not impose any specific restrictions on this.

[0035] The inverter 103 is usually composed of an inverter circuit, and the inverter circuit is generally composed of a power semiconductor device (Insulated Gate Bipolar Transistor, IGBT). During the inversion process, in order to avoid short circuit of the inverter, the signal controlling the inversion usually needs to set a dead time so that the IGBTs used for inversion in the inverter are disconnected at the same time. There is a dead time for each inversion cycle, and a certain conduction voltage drop is required each time the IGBT is turned on. Since the switching frequency of the IGBT is high, there are a large number of inversion cycles per unit time. Then, after the effects of the dead time and the conduction voltage drop are superimposed, the input voltage of the motor generates high-order harmonics. The vehicle 100 can determine the input voltage of the motor 102 after suppressing the high-order harmonics through the controller 101.

[0036] in addition, Figure 1 The vehicle structure shown in the figure is merely an exemplary description and should not be regarded as limiting the scope of protection of the present application.

[0037] In the related art, the influence of high-order harmonics on the motor is generally weakened by adjusting the dead time of the IGBT in the inverter. Although this solution can weaken the high-order harmonics, the dead time of the IGBT still exists, so that the motor still generates harmonic torque, thereby causing the motor torque pulsation phenomenon.

[0038] In view of the above problems, in the embodiment of the present application, the vehicle extracts high-order harmonic current from the output current of the motor, determines the high-order harmonic voltage according to the high-order harmonic current, and suppresses the high-order harmonic by removing the high-order harmonic voltage from the target voltage of the motor. Since the high-order harmonic is weakened as much as possible, the harmonic torque of the motor is weakened, thereby weakening the problem of motor torque pulsation.

[0039] Specifically, a detailed description is given below in conjunction with the accompanying drawings and specific embodiments.

[0040] See also Figure 2 , which is a flow chart of a motor control method provided in an embodiment of the present application. The method can be applied to Figure 1 The controller in the application scenario shown in FIG. Figure 2 As shown, it mainly includes the following steps.

[0041] Step S201: converting the three-phase current output by the motor into the D-axis output current and the Q-axis output current of the motor.

[0042] See also Figure 3 , which is a flow chart of a three-phase current signal coordinate system transformation method provided in the present application embodiment. Figure 3 As shown, it mainly includes the following steps.

[0043] Step S301: Acquire the three-phase current of the motor.

[0044] The controller obtains the three-phase current of the motor , , The phase difference between the three is 120°, and the waveform of each current signal changing with time is ideally a sine wave. The three-phase current of the motor usually refers to the current on the stator.

[0045] Step S302: Convert the three-phase current signal to Coordinate system.

[0046] Through Clerk transformation, the three-phase current signal , , Transform to Coordinate system. In the coordinate system, Axis and Current component on the axis , The phase difference between them is 90 degrees. , A waveform that varies with time, ideally a sine wave.

[0047] Step S303: Convert the current signal from The coordinate system is transformed to the DQ coordinate system.

[0048] Through Park transformation, the current signal is transformed from The coordinate system is transformed to the DQ coordinate system. The DQ coordinate system is a synchronously rotating orthogonal coordinate system, in which the D axis is consistent 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 the 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 the Q axis, that is, the D axis output current and the Q axis output current, are two constant values ​​under ideal conditions.

[0049] Through Clerk transformation and Park transformation, the three-phase current signal of the motor is transformed into the DQ coordinate system, and the three-phase current on the stator is equivalent to the D axis and Q axis, which simplifies the analysis of the motor operation.

[0050] Step S202: Determine the D-axis high-order harmonic voltage and the Q-axis high-order harmonic voltage according to the D-axis output current and the Q-axis output current.

[0051] See also Figure 4 , which is a flow chart of a method for determining a high-order harmonic voltage according to an embodiment of the present application. Figure 4 As shown, it mainly includes the following steps.

[0052] Step S401: extracting a D-axis high-order harmonic mapping current and a Q-axis high-order harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a transformation matrix.

[0053] In the embodiment of the present application, the transformation matrix refers to the synchronous rotation transformation matrix used when extracting high-order harmonics from the first DQ coordinate system into the second DQ coordinate system through synchronous rotation transformation. Among them, the D axis and Q axis of the first DQ coordinate system are consistent with the direction of the magnetic field that generates the output current and rotate synchronously; the D axis and Q axis of the second DQ coordinate system are consistent with the direction of the magnetic field that generates the high-order harmonic current and rotate synchronously.

[0054] It is further understood that in the first DQ coordinate system, the components of the output current of the motor in the D-axis and Q-axis are constant values. However, in the first DQ coordinate system, the rotation speeds of the D-axis and Q-axis are inconsistent with the rotation speed of the magnetic field that generates the high-order harmonic current. Therefore, the D-axis component and Q-axis component of the high-order harmonic current in the first DQ coordinate system are not constant values. For ease of analysis, the high-order harmonic current needs to be transformed into the second DQ coordinate system. In the second DQ coordinate system, the components of the high-order harmonic current in the D-axis and Q-axis are constant values. Then, the matrix used to transform the high-order harmonic current from the first DQ coordinate system to the second DQ coordinate system is the transformation matrix.

[0055] In a possible implementation, a D-axis high-order harmonic mapping current and a Q-axis high-order harmonic mapping current are extracted from the D-axis output current and the Q-axis output current respectively through a transformation matrix.

[0056] By transforming the matrix, the high-order harmonic current is transformed into the second DQ coordinate system. In the second DQ coordinate system, the D-axis component and the Q-axis component of the high-order harmonic current are constant values, and the high-order harmonic current can be extracted. In the embodiment of the present application, the D-axis component and the Q-axis component of the high-order harmonic current in the second DQ coordinate system are respectively referred to as the D-axis high-order harmonic mapping current, and the Q-axis component is referred to as the Q-axis high-order harmonic mapping current.

[0057] In a possible implementation, a D-axis fifth harmonic mapping current and a Q-axis fifth harmonic mapping current are extracted from the D-axis output current and the Q-axis output current respectively through a first transformation matrix.

[0058] The first transformation matrix is ​​shown as matrix (1): Matrix (1) in, means The angle between the A axis and the D axis.

[0059] The first transformation matrix is ​​a synchronous rotation transformation matrix used to transform the 5th harmonic current into the third DQ coordinate system. Among them, the D-axis and Q-axis of the third DQ coordinate system are consistent with the direction of the magnetic field that generates the 5th harmonic current and rotate synchronously. In the third DQ coordinate system, the D-axis component and Q-axis component of the 5th harmonic current are constant values, and the 5th harmonic current can be extracted. In the embodiment of the present application, the D-axis component and Q-axis component of the 5th harmonic current in the third DQ coordinate system are respectively referred to as the D-axis 5th harmonic mapping current and the Q-axis 5th harmonic mapping current.

[0060] In a possible implementation, a D-axis seventh harmonic mapping current and a Q-axis seventh harmonic mapping current are respectively extracted from the D-axis output current and the Q-axis output current through a second transformation matrix.

[0061] The second transformation matrix is ​​shown in matrix (2): Matrix (2) in, means The angle between the A axis and the D axis.

[0062] The second transformation matrix is ​​a synchronous rotation transformation matrix used to transform the 7th harmonic current into the fourth DQ coordinate system. Among them, the D-axis and Q-axis of the fourth DQ coordinate system are consistent with the direction of the magnetic field that generates the 7th harmonic current and rotate synchronously. In the fourth DQ coordinate system, the D-axis component and Q-axis component of the 7th harmonic current are constant values, and the 7th harmonic current can be extracted. In an embodiment of the present application, the D-axis component and Q-axis component of the 7th harmonic current in the fourth DQ coordinate system are respectively referred to as the D-axis 7th harmonic mapping current and the Q-axis 7th harmonic mapping current.

[0063] In one possible implementation, the D-axis 5th harmonic mapping current and the Q-axis 5th harmonic mapping current can be extracted from the D-axis output current and the Q-axis output current respectively through the first transformation matrix, and the D-axis 7th harmonic mapping current and the Q-axis 7th harmonic mapping current can be extracted from the D-axis output current and the Q-axis output current respectively through the second transformation matrix.

[0064] See also Figure 5 , which is a flow chart of a method for determining a high-order harmonic mapping current according to an embodiment of the present application. Figure 5 As shown, it mainly includes the following steps.

[0065] Step S501: extracting a D-axis initial high-order harmonic mapping current and a Q-axis initial high-order harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a transformation matrix.

[0066] In practical applications, affected by nonlinear loads (such as inverters, rectifiers, etc.), noise may exist in the D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current extracted from the D-axis output current and the Q-axis output current respectively through the transformation matrix. In the second DQ coordinate system, the D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current should theoretically be constant values. Due to the existence of noise, the waveforms of the D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current fluctuate.

[0067] In the embodiment of the present application, the D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current that may have noise in the second DQ coordinate system are respectively referred to as the D-axis initial high-order harmonic mapping current and the Q-axis initial high-order harmonic mapping current. In order to improve the accuracy of the D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current, it is necessary to perform noise removal on the D-axis initial high-order harmonic mapping current and the Q-axis initial high-order harmonic mapping current.

[0068] Step S502: filtering the D-axis initial high-order harmonic mapping current and the Q-axis initial high-order harmonic mapping current respectively through a low-pass filter to obtain the D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current.

[0069] In one possible implementation, the D-axis initial high-order harmonic mapping current and the Q-axis initial high-order harmonic mapping current are filtered respectively by a low-pass filter to obtain the D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current, thereby improving the accuracy of the D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current.

[0070] Step S402: integrating the D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current respectively through a proportional-integral controller to obtain a D-axis high-order harmonic mapping voltage and a Q-axis high-order harmonic mapping voltage.

[0071] It should be noted that the process of obtaining the D-axis high-order harmonic mapping voltage and the Q-axis high-order harmonic mapping voltage is performed in the second DQ coordinate system.

[0072] In a possible implementation, the D-axis fifth harmonic mapping current and the Q-axis fifth harmonic mapping current are respectively integrated by a first proportional-integral controller to obtain a D-axis fifth harmonic mapping voltage and a Q-axis fifth harmonic mapping voltage.

[0073] It should be noted that the process of obtaining the D-axis fifth harmonic mapping voltage and the Q-axis fifth harmonic mapping voltage is performed in the third DQ coordinate system.

[0074] In a possible implementation, the D-axis 7th harmonic mapping current and the Q-axis 7th harmonic mapping current are respectively integrated by a second proportional-integral controller to obtain a D-axis 7th harmonic mapping voltage and a Q-axis 7th harmonic mapping voltage.

[0075] It should be noted that the process of obtaining the D-axis seventh harmonic mapping voltage and the Q-axis seventh harmonic mapping voltage is performed in the fourth DQ coordinate system.

[0076] In one possible implementation, in the third DQ coordinate system, the D-axis 5th harmonic mapping current and the Q-axis 5th harmonic mapping current can be integrated respectively by the first proportional-integral controller to obtain the D-axis 5th harmonic mapping voltage and the Q-axis 5th harmonic mapping voltage, and in the fourth DQ coordinate system, the D-axis 7th harmonic mapping current and the Q-axis 7th harmonic mapping current can be integrated respectively by the second proportional-integral controller to obtain the D-axis 7th harmonic mapping voltage and the Q-axis 7th harmonic mapping voltage.

[0077] Step S403: converting the D-axis high-order harmonic mapping voltage and the Q-axis high-order harmonic mapping voltage into the D-axis high-order harmonic voltage and the Q-axis high-order harmonic voltage through an inverse transformation matrix.

[0078] In the embodiment of the present application, the inverse transformation matrix is ​​a synchronous rotation transformation matrix used when the high-order harmonic voltage is transformed from the second DQ coordinate system to the first DQ coordinate system through synchronous rotation.

[0079] The D-axis high-order harmonic mapping voltage and the Q-axis high-order harmonic mapping voltage can be converted from the second DQ coordinate system to the first DQ coordinate system through the inverse transformation matrix, so that the D-axis high-order harmonic voltage and the Q-axis high-order harmonic voltage can be obtained in the first DQ coordinate system.

[0080] In a possible implementation, the D-axis fifth harmonic mapping voltage and the Q-axis fifth harmonic mapping voltage are converted into the D-axis fifth harmonic voltage and the Q-axis fifth harmonic voltage by using a first inverse transformation matrix.

[0081] The first inverse transformation matrix is ​​shown in matrix (3): Matrix (3) in, means The angle between the A axis and the D axis.

[0082] The first inverse transformation matrix is ​​a synchronous rotation transformation matrix used to transform the 5th harmonic mapping voltage from the third DQ coordinate system to the first DQ coordinate system. Through the first inverse transformation matrix, the D-axis 5th harmonic mapping voltage and the Q-axis 5th harmonic mapping voltage can be converted from the third DQ coordinate system to the first DQ coordinate system, so that the D-axis 5th harmonic voltage and the Q-axis 5th harmonic voltage can be obtained in the first DQ coordinate system.

[0083] In a possible implementation, the D-axis seventh harmonic mapping voltage and the Q-axis seventh harmonic mapping voltage are converted into the D-axis seventh harmonic voltage and the Q-axis seventh harmonic voltage by a second inverse transformation matrix.

[0084] The second inverse transformation matrix is ​​shown in matrix (4): Matrix (4) in, means The angle between the A axis and the D axis.

[0085] The second inverse transformation matrix is ​​a synchronous rotation transformation matrix used to transform the 7th harmonic mapping voltage from the fourth DQ coordinate system to the first DQ coordinate system. Through the second inverse transformation matrix, the D-axis 7th harmonic mapping voltage and the Q-axis 7th harmonic mapping voltage can be converted from the fourth DQ coordinate system to the first DQ coordinate system, so that the D-axis 7th harmonic voltage and the Q-axis 7th harmonic voltage can be obtained in the first DQ coordinate system.

[0086] In one possible implementation, the D-axis 5th harmonic mapping voltage and the Q-axis 5th harmonic mapping voltage can be converted into the D-axis 5th harmonic voltage and the Q-axis 5th harmonic voltage through the first inverse transformation matrix, and the D-axis 7th harmonic mapping voltage and the Q-axis 7th harmonic mapping voltage can be converted into the D-axis 7th harmonic voltage and the Q-axis 7th harmonic voltage through the second inverse transformation matrix.

[0087] In practical applications, since higher harmonics higher than the 7th harmonic, such as the 9th harmonic, the 11th harmonic, the 13th harmonic, etc., have little effect on the torque pulsation problem of the motor. If all higher harmonics higher than the 7th harmonic are suppressed, a large amount of equipment needs to be invested, and the cost performance is not high. Therefore, in the embodiment of the present application, the 5th harmonic and the 7th harmonic are mainly suppressed.

[0088] Step S203: Determine the D-axis target voltage and the Q-axis target voltage of the motor according to the target torque of the motor.

[0089] See also Figure 6 , is a flow chart of a method for determining a target voltage according to an embodiment of the present application. Figure 6 As shown, it mainly includes the following steps.

[0090] Step S601: Determine the D-axis target current and Q-axis target current of the motor according to the target torque of the motor.

[0091] In practical applications, due to the influence of nonlinear loads, there is an error fluctuation between the actual output current and the target current of the motor, 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.

[0092] See also Figure 7 , which is a flow chart of a method for determining a target current according to an embodiment of the present application. Figure 7 As shown, it mainly includes the following steps.

[0093] Step S701: Determine the D-axis initial target current and the Q-axis initial target current of the motor according to the target torque of the motor.

[0094] The initial target current of the D axis and the initial target current of the Q axis are theoretical values ​​determined based on the target torque of the motor. The goal is to obtain the target output by inputting this value into the motor. In practical applications, due to factors such as nonlinear loads, there is an error between the actual output of the motor and the target output value. Therefore, it is necessary to control the error between the actual output of the motor and the target output.

[0095] In a possible implementation, a negative feedback control method is used to control the output of the motor.

[0096] Negative feedback refers to the error between the initial target current of the D-axis and the output current of the D-axis, and the error between the initial target current of the Q-axis and the output current of the Q-axis based on the motor. The error is used for adjustment so that the output of the motor changes according to the given input, so that the output of the motor gradually approaches the target output.

[0097] Step S702: Determine the D-axis target current of the motor according to the D-axis initial target current and the D-axis output current.

[0098] The D-axis target current of the motor is determined based on the difference between the D-axis initial target current and the D-axis output current, and the D-axis initial target current.

[0099] Step S703: Determine the Q-axis target current of the motor according to the Q-axis initial target current and the Q-axis output current.

[0100] The Q-axis target current of the motor is determined based on the difference between the Q-axis initial target current and the Q-axis output current, and the Q-axis initial target current.

[0101] Step S602: integrating the D-axis target current and the Q-axis target current respectively through a third proportional-integral controller to obtain a D-axis target voltage and a Q-axis target voltage.

[0102] Through step S601 - step S602 , a D-axis target voltage and a Q-axis target voltage may be obtained based on the target torque of the motor.

[0103] Step S204: Calculate the difference between the D-axis target voltage and the D-axis high-order 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 high-order harmonic voltage to obtain the Q-axis input voltage of the motor.

[0104] By making a difference, the D-axis high-order harmonic voltage and the Q-axis high-order harmonic voltage are removed from the D-axis target voltage and the Q-axis target voltage respectively, thereby achieving the purpose of suppressing high-order harmonics.

[0105] Exemplarily, if the three-phase input voltage of the motor is 380V, but affected by the higher harmonics generated during the inversion process, the three-phase input voltage of the motor is 390V, then the higher harmonic voltage is 10V. In order 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 D-axis target voltage and the D-axis higher harmonic voltage are calculated by difference to obtain the D-axis input voltage of the motor; the Q-axis target voltage and the Q-axis higher harmonic voltage are calculated by difference to obtain the Q-axis input voltage of the motor. At this time, the D-axis input voltage and the Q-axis input voltage are converted into the three-phase input voltage of the motor, which is 370V. The three-phase input voltage of the motor is then passed through the inverter circuit in the inverter, and higher harmonics will be generated during the inversion process. Affected by the higher harmonics, the actual three-phase input voltage of the motor is 380V, thereby achieving the purpose of suppressing higher harmonics.

[0106] Step S205: Convert the D-axis input voltage and the Q-axis input voltage into a three-phase input voltage of the motor.

[0107] First, the D-axis input voltage and Q-axis input voltage are transformed into Secondly, through the space vector pulse width modulation algorithm, In the coordinate system Shaft input voltage and The shaft input voltage is converted into a three-phase drive signal for the inverter circuit in the inverter. Then, the IGBT in the inverter circuit is driven according to the three-phase drive signal to convert the DC power into the three-phase input voltage of the motor.

[0108] Corresponding to the above method embodiment, the present application also provides a motor control device. Specifically, see Figure 8 , is a schematic diagram of the structure of a motor control device provided in an embodiment of the present application. Figure 8 As shown, the figure shows a motor control device 800. 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 the Q-axis output current of the motor, wherein the D-axis has the same magnetic flux direction as the rotor of the motor, and the Q-axis is perpendicular to the magnetic flux direction of the rotor of the motor; the harmonic voltage determination device 802 is used to determine the D-axis high-order harmonic voltage and the Q-axis high-order harmonic voltage according to the D-axis output current and the Q-axis output current; the target voltage determination device 803 is used to determine the D-axis target voltage and the Q-axis target voltage of the motor according to the target torque of the motor; the input voltage determination device 804 is used to calculate the difference between the D-axis target voltage and the D-axis high-order harmonic voltage to obtain the D-axis input voltage of the motor; the Q-axis target voltage and the Q-axis high-order harmonic voltage are calculated 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.

[0109] The specific contents involved in the embodiments of the present application can be found in the description of the above method embodiments. For the sake of brevity, they will not be elaborated on here.

[0110] Corresponding to the above method embodiment, the present application also provides a vehicle. The vehicle specifically includes a controller for executing some or all of the steps in the above method embodiment, which will not be described in detail for the sake of brevity.

[0111] Corresponding to the above method embodiments, the present application also provides a computer storage medium, wherein the computer storage medium may store a program, and when the program is executed, the program may include some or all of the steps in each embodiment of the simulation scene generation method provided by the present invention. The storage medium may be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0112] In the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated 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 be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0113] Those of ordinary skill in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented in a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0114] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0115] In several embodiments provided in the present application, if any function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0116] In this specification, the same or similar parts between the various embodiments can be referred to each other. In particular, for the device embodiment and the terminal embodiment, since they are basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description in the method embodiment.

Claims

1. A motor control method, characterized in that: The motor is a three-phase AC motor, and the method comprises: Converting the three-phase current output by the motor into a D-axis output current and a Q-axis output current of the motor, wherein the D-axis has the same direction as the magnetic flux of the rotor of the motor, and the Q-axis is perpendicular to the magnetic flux of the rotor of the motor; Determining a D-axis high-order harmonic voltage and a Q-axis high-order harmonic voltage according to the D-axis output current and the Q-axis output current; Determining a D-axis target voltage and a Q-axis target voltage of the motor according to a target torque of the motor; The D-axis target voltage and the D-axis high-order harmonic voltage are calculated to obtain the D-axis input voltage of the motor; the Q-axis target voltage and the Q-axis high-order harmonic voltage are 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 a three-phase input voltage of the motor.

2. The method according to claim 1, characterized in that The determining of the D-axis high-order harmonic voltage and the Q-axis high-order harmonic voltage according to the D-axis output current and the Q-axis output current comprises: Extracting a D-axis high-order harmonic mapping current and a Q-axis high-order harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a transformation matrix; The D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current are respectively integrated by a proportional-integral controller to obtain a D-axis high-order harmonic mapping voltage and a Q-axis high-order harmonic mapping voltage; The D-axis high-order harmonic mapping voltage and the Q-axis high-order harmonic mapping voltage are converted into a D-axis high-order harmonic voltage and a Q-axis high-order harmonic voltage through an inverse transformation matrix.

3. The method according to claim 2, characterized in that The determining of the D-axis high-order harmonic voltage and the Q-axis high-order harmonic voltage according to the D-axis output current and the Q-axis output current comprises: Extracting the D-axis 5th harmonic mapping current and the Q-axis 5th harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a first transformation matrix; and / or extracting the D-axis 7th harmonic mapping current and the Q-axis 7th harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a second transformation matrix; The D-axis 5th harmonic mapping current and the Q-axis 5th harmonic mapping current are respectively integrated by a first proportional-integral controller to obtain a D-axis 5th harmonic mapping voltage and a Q-axis 5th harmonic mapping voltage; and / or, the D-axis 7th harmonic mapping current and the Q-axis 7th harmonic mapping current are respectively integrated by a second proportional-integral controller to obtain a D-axis 7th harmonic mapping voltage and a Q-axis 7th harmonic mapping voltage; The D-axis 5th harmonic mapping voltage and the Q-axis 5th harmonic mapping voltage are converted into the D-axis 5th harmonic voltage and the Q-axis 5th harmonic voltage through a first inverse transformation matrix; and / or, the D-axis 7th harmonic mapping voltage and the Q-axis 7th harmonic mapping voltage are converted into the D-axis 7th harmonic voltage and the Q-axis 7th harmonic voltage through a second inverse transformation matrix.

4. The method according to claim 2, characterized in that: The extracting of the D-axis high-order harmonic mapping current and the Q-axis high-order harmonic mapping current from the D-axis output current and the Q-axis output current respectively by using a transformation matrix includes: Extracting a D-axis initial high-order harmonic mapping current and a Q-axis initial high-order harmonic mapping current from the D-axis output current and the Q-axis output current respectively through a transformation matrix; The D-axis initial high-order harmonic mapping current and the Q-axis initial high-order harmonic mapping current are filtered respectively by a low-pass filter to obtain a D-axis high-order harmonic mapping current and a Q-axis high-order harmonic mapping current.

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

6. The method according to claim 5, characterized in that Determining a D-axis target current and a Q-axis target current of the motor according to the target torque of the motor includes: Determining an initial target current of a D axis and an initial target current of a Q axis of the motor according to a target torque of the motor; Determining a D-axis target current of the motor according to the D-axis initial target current and the D-axis output current; The Q-axis target current of the motor is determined according to the Q-axis initial target current and the Q-axis output current.

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 a three-phase input voltage of the motor includes: Converting the D-axis input voltage and the Q-axis input voltage into an α-axis input voltage and a β-axis input voltage in an αβ coordinate system; The α-axis input voltage and the β-axis input voltage are converted into a 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 comprises: An output current conversion device, used for converting the three-phase current output by the motor into a D-axis output current and a Q-axis output current of the motor, wherein the D-axis has the same direction as the magnetic flux of the rotor of the motor, and the Q-axis is perpendicular to the magnetic flux of the rotor of the motor; A harmonic voltage determining device, used for determining a D-axis high-order harmonic voltage and a Q-axis high-order harmonic voltage according to the D-axis output current and the Q-axis output current; a target voltage determination device, for determining a D-axis target voltage and a Q-axis target voltage of the motor according to a target torque of the motor; An input voltage determination device, used for performing a difference calculation between the D-axis target voltage and the D-axis higher harmonic voltage to obtain the D-axis input voltage of the motor; performing a difference calculation 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 a three-phase input voltage of the motor.

9. A vehicle, characterized in that: include: A controller, wherein the controller is configured to execute the method according to 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, the device where the computer-readable storage medium is located is controlled to execute the method according to any one of claims 1 to 7.

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