Electric vehicle motor vector control method and electric vehicle motor control device

Abstract

The invention relates to an electric vehicle motor vector control method and an electric vehicle motor control device, and the method comprises the steps: obtaining a current value and a voltage value of a motor, and a first electric angular speed of the motor when an electric vehicle runs; inputting the current value, the voltage value and the first electrical angular velocity into a sliding mode flux linkage observer under the condition that the first electrical angular velocity is greater than a preset threshold value to obtain a first rotor flux linkage parameter; inputting the current value, the voltage value and the first rotor flux linkage parameter into a nonlinear flux linkage observer to obtain a second rotor flux linkage parameter; performing arc tangent calculation on the second rotor flux linkage parameter to obtain a target electrical angle, and performing differential calculation on the target electrical angle to obtain a target electrical angular velocity; and inputting the target electrical angle and the target electrical angular velocity into a double-closed-loop control system, so that the double-closed-loop control system performs vector control on the motor. According to the invention, the problem that the vector control accuracy of the motor is low is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of motor control, and in particular, relates to a vector control method for an electric vehicle motor and an electric vehicle motor control device. Background Art

[0002] Electric vehicles (e.g., two-wheeled electric vehicles or three-wheeled electric vehicles) have become the main means of transportation for many families as a convenient and environmentally friendly means of transportation. The motor is the driving component of the electric vehicle, so the motor will directly affect the performance indicators of the electric vehicle such as climbing ability and driving range, and permanent magnet synchronous motors are widely used in electric vehicles because of their excellent performance.

[0003] At present, permanent magnet synchronous motors in electric vehicles are often controlled based on Hall sensors, and vector control calculations are performed based on the motor rotor position detected by the Hall sensors. However, installing Hall sensors in motors increases costs, increases the motor volume and the rotational inertia of the shaft, and reduces the power density of the motor. In addition, Hall sensors are easily affected by temperature and electromagnetic noise. These factors will cause the motor electrical angle calculated by the Hall sensor to deviate from the actual electrical angle, which will greatly reduce the accuracy of vector control of the motor and may even make it impossible to control the normal operation of the motor.

[0004] Currently, there is no effective solution to the problem of low accuracy of vector control of motors. Summary of the invention

[0005] The embodiments of the present application provide an electric vehicle motor vector control method, an electric vehicle motor control device, an electric vehicle and a computer program product to at least solve the problem of low accuracy of vector control of the motor.

[0006] In a first aspect, an embodiment of the present application provides a method for vector control of an electric vehicle motor, the method comprising: when the electric vehicle is running, obtaining a current value and a voltage value of the motor, and a first electrical angular velocity of the motor; when the first electrical angular velocity is greater than a preset threshold, inputting the current value, the voltage value and the first electrical angular velocity into a sliding film flux observer to obtain a first rotor flux parameter; inputting the current value, the voltage value and the first rotor flux parameter into a nonlinear flux observer to obtain a second rotor flux parameter; performing an inverse tangent calculation on the second rotor flux parameter to obtain a target electrical angle, and performing a differential calculation on the target electrical angle to obtain a target electrical angular velocity; inputting the target electrical angle and the target electrical angular velocity into a dual closed-loop control system so that the dual closed-loop control system performs vector control on the motor.

[0007] In some embodiments, inputting the current value, the voltage value and the first electrical angular velocity into the sliding film flux observer to obtain the first rotor flux parameter includes: inputting the current value and the voltage value into the sliding film flux observer to obtain the current observation error; based on the current observation error and the preset sliding film arrival condition, determining the observation component of the back electromotive force generated by the permanent magnet in the motor under the α-axis and the β-axis of the two-phase stationary coordinate system; based on the observation component and the first electrical angular velocity, determining the first rotor flux parameter, wherein the mathematical expression of the first rotor flux parameter is:

[0008]

[0009] in, is the first rotor flux parameter, ω e is the first electrical angular velocity, is the observed component of the back electromotive force generated by the permanent magnet under the α axis, is the observed component of the back electromotive force generated by the permanent magnet under the β axis.

[0010] In some embodiments, inputting the current value and the voltage value into the sliding film flux observer to obtain the current observation error includes: pre-building the sliding film flux observer, wherein the mathematical expression of the sliding film flux observer is:

[0011]

[0012] in, is the observed current value of the motor under the α axis, is the observed current value of the motor under the β axis, z α and z β is the synovial control function, R s is the stator resistance, L s is the synchronous inductance of the motor, u α is the voltage value of the motor under the α axis, u β is the voltage value of the motor under the β axis; select the sliding film switching surface, where the mathematical expression of the sliding film switching surface is:

[0013]

[0014] Among them, i α is the current value of the motor under the α axis, i β is the current value of the motor under the β axis; determine the synovial control function, where the mathematical expression of the synovial control function is:

[0015]

[0016] Among them, k is the sign function coefficient, sgn is the sign function, and the expression of the sign function is as follows:

[0017]

[0018] Based on the sliding film flux observer, the sliding film switching surface and the sliding film control function, the current observation error is calculated, where the mathematical expression of the current observation error is:

[0019]

[0020] Among them, e α is the component of the back electromotive force generated by the permanent magnet under the α axis, e β is the component of the back electromotive force generated by the permanent magnet under the β axis.

[0021] In some embodiments, obtaining the current value and voltage value of the motor, and the first electrical angular velocity of the motor includes: obtaining the current value, the voltage value and the preset rotor flux parameters of the motor; inputting the current value, the voltage value and the preset rotor flux parameters into a nonlinear flux observer to obtain a third rotor flux parameter; performing an inverse tangent calculation on the third rotor flux parameter to obtain a first electrical angle, and performing a differential calculation on the first electrical angle to obtain a first electrical angular velocity.

[0022] In some embodiments, inputting the current value, the voltage value and the preset rotor flux parameter into the nonlinear flux observer to obtain the third rotor flux parameter includes: constructing a state variable and an input variable based on the current value, the voltage value and the preset rotor flux parameter, wherein the mathematical expression of the state variable is:

[0023]

[0024] Among them, i α is the current value of the motor under the α axis, i β is the current value of the motor under the β axis, L s is the synchronous inductance of the motor, ψ f is the preset rotor flux parameter, θ e is the electrical angle of the motor; the mathematical expression of the input variable is:

[0025]

[0026] Among them, u α is the voltage value of the motor under the α axis, u β is the voltage value of the motor under the β axis, R s is the stator resistance; based on the state variables, the input variables and the nonlinear flux observer, the third rotor flux parameter is determined, wherein the mathematical expression of the nonlinear flux observer is:

[0027]

[0028] Where p is the differential operator, γ is the observer gain, is the estimated value of the state variable, is the third rotor flux parameter, and the mathematical expression of η(x) is:

[0029]

[0030] In some embodiments, after obtaining the current value and voltage value of the motor, and the first electrical angular velocity of the motor, the method also includes: when the first electrical angular velocity is less than a preset threshold, inputting the first electrical angle and the first electrical angular velocity into a dual closed-loop control system, so that the dual closed-loop control system performs vector control on the motor.

[0031] In some embodiments, the current value and the voltage value are the current value and the voltage value of the motor in a two-phase stationary coordinate system; obtaining the current value and the voltage value of the motor includes: obtaining the three-phase current value and the three-phase voltage value of the motor; using Clark transformation to convert the three-phase current value and the three-phase voltage value into the current value and the voltage value of the motor in a two-phase stationary coordinate system.

[0032] In the second aspect, an embodiment of the present application provides an electric vehicle motor control device, including: an acquisition module, used to acquire the current value and voltage value of the motor, and the first electrical angular velocity of the motor when the electric vehicle is running; a first observation module, used to input the current value, voltage value and first electrical angular velocity into a sliding film flux observer when the first electrical angular velocity is greater than a preset threshold value, so as to obtain a first rotor flux parameter; a second observation module, used to input the current value, voltage value and first rotor flux parameter into a nonlinear flux observer, so as to obtain a second rotor flux parameter; a calculation module, used to perform an inverse tangent calculation on the second rotor flux parameter to obtain a target electrical angle, and perform a differential calculation on the target electrical angle to obtain a target electrical angular velocity; a control module, used to input the target electrical angle and the target electrical angular velocity into a dual closed-loop control system, so that the dual closed-loop control system performs vector control on the motor.

[0033] In a third aspect, an embodiment of the present application provides an electric vehicle, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the electric vehicle motor vector control method of any one of the above-mentioned first aspects is implemented.

[0034] In a fourth aspect, an embodiment of the present application provides a computer program product, including a computer program. When the computer program is executed, the electric vehicle motor vector control method described in any one of the above-mentioned first aspects is executed.

[0035] The electric vehicle motor vector control method, electric vehicle motor control device, electric vehicle and computer program product provided by the embodiment of the present application, by obtaining various parameters of the motor in real time when the electric vehicle is running, when the speed of the motor is greater than the preset threshold, the sliding film flux linkage observer is used to observe the current flux linkage parameters of the motor, instead of directly inputting the default flux linkage parameters of the motor (or the measured real flux linkage parameters of the permanent magnet in the motor) directly into the nonlinear flux linkage observer, which can avoid the measurement error of the default flux linkage parameters or the demagnetization phenomenon generated during the operation of the permanent magnet. The default flux linkage parameters and the current flux linkage parameters are inconsistent, which affect the observation accuracy of the nonlinear flux linkage observer; then the current flux linkage parameters observed by the sliding film flux linkage observer are input into the nonlinear flux linkage observer, and the nonlinear flux linkage observer is used to observe the position and speed of the motor in a non-mechanical sensor-free manner, avoiding the high cost caused by the use of mechanical sensors, increasing the complexity of motor design, reducing the accuracy of vector control, and other defects, thereby improving the accuracy of vector control of the motor. Through this application, the problem of low accuracy of vector control of the motor is solved, and the technical effect of improving the accuracy of vector control of the motor is achieved.

[0036] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art 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 any creative work.

[0038] Figure 1 is a flow chart of a method for vector control of an electric vehicle motor according to an embodiment of the present application;

[0039] Figure 2 is a structural block diagram of an electric vehicle motor vector control system according to an embodiment of the present application;

[0040] Figure 3 is a structural block diagram of a nonlinear flux observer according to an embodiment of the present application;

[0041] Figure 4 is a structural block diagram of a sliding film flux observer according to an embodiment of the present application;

[0042] Figure 5 is a structural schematic diagram of an electric vehicle motor control device according to an embodiment of the present application;

[0043] Figure 6 It is a schematic structural diagram of an electric vehicle according to an embodiment of the present application. DETAILED DESCRIPTION

[0044] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0045] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0046] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0047] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0048] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0049] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0050] As a convenient and environmentally friendly means of transportation, electric vehicles have become the main means of travel for many families. The motor is the driving component of the electric vehicle, so the motor will directly affect the performance indicators of the electric vehicle such as climbing ability and driving range, and the permanent magnet synchronous motor is widely used in electric vehicles because of its excellent performance. The electric vehicle provided in the embodiment of the present application can be a two-wheeled electric vehicle or a three-wheeled electric vehicle.

[0051] At present, permanent magnet synchronous motors in electric vehicles are often controlled based on Hall sensors, and vector control calculations are performed based on the motor rotor position detected by the Hall sensors. However, installing Hall sensors in motors increases costs, increases the motor volume and the rotational inertia of the shaft, and reduces the power density of the motor. In addition, Hall sensors are easily affected by temperature and electromagnetic noise. These factors will cause the motor electrical angle calculated by the Hall sensor to deviate from the actual electrical angle, which will greatly reduce the accuracy of vector control of the motor and may even make it impossible to control the normal operation of the motor.

[0052] Currently, there is no effective solution to the problem of low accuracy of vector control of motors.

[0053] In view of this, an embodiment of the present application provides a method for vector control of an electric vehicle motor, which is applied to control a motor in a two-wheeled electric vehicle or a three-wheeled electric vehicle. By acquiring various parameters of the motor in real time when the electric vehicle is running, when the speed of the motor is greater than a preset threshold, a sliding film flux observer is used to observe the current flux parameters of the motor, instead of directly inputting the default flux parameters of the motor (or the actual flux parameters of the permanent magnet in the motor obtained by measurement) into the nonlinear flux observer. This can avoid the measurement error of the default flux parameters or the inconsistency between the default flux parameters and the current flux parameters caused by the demagnetization phenomenon generated during the operation of the permanent magnet. The impact on the observation accuracy of the nonlinear flux observer can be avoided; then the current flux parameters observed by the sliding film flux observer are input into the nonlinear flux observer, and the nonlinear flux observer is used to observe the position and speed of the motor in a mechanical sensor-free manner, thereby avoiding the high cost caused by the use of mechanical sensors, increased motor design complexity, reduced vector control accuracy, and other defects, thereby improving the accuracy of vector control of the motor. Through the present application, the problem of low accuracy of vector control of the motor is solved, and the technical effect of improving the accuracy of vector control of the motor is achieved.

[0054] The following will be combined Figure 1 For an explanation of the electric vehicle motor vector control method provided by an embodiment of the present application, please refer to Figure 1 , Figure 1 is a flow chart of a method for vector control of an electric vehicle motor according to an embodiment of the present application. Figure 1 As shown, the method includes:

[0055] Step S101, when the electric vehicle is running, obtaining the current value and voltage value of the motor, and the first electrical angular velocity of the motor.

[0056] In this embodiment, the current value and voltage value of the motor can be the current value i of the motor in the two-phase stationary coordinate system. α 、i β (collectively referred to as i αβ ) and voltage value u α 、u β (collectively referred to as U αβ ). Among them, the current value i αβ And voltage value U αβ The acquisition process may include: when the electric vehicle is running, obtaining the three-phase current value i of the motor abc And the three-phase voltage value U abc ; Use Clark transformation to transform the three-phase current value i abc And the three-phase voltage value U abc Converted into the current value i of the motor in the two-phase stationary coordinate system αβ And voltage value U αβ .

[0057] Among them, the mathematical formula of Clark transformation can be:

[0058]

[0059] As an example, see Figure 2 , Figure 2 is a structural block diagram of an electric vehicle motor vector control system according to an embodiment of the present application, such as Figure 2 As shown, when the electric vehicle is running, the three-phase current value i of the motor 200 can be obtained first. abc And the three-phase voltage value U abc , and then the three-phase current value i abc And the three-phase voltage value U abc Input the Clark transformation unit 201 to obtain the current value i output by the Clark transformation unit 201 αβ And voltage value U α β.

[0060] In this embodiment, the process of obtaining the first electrical angular velocity of the motor may include: obtaining the current value, the voltage value and the preset rotor flux parameters of the motor; inputting the current value, the voltage value and the preset rotor flux parameters into a nonlinear flux observer to obtain the third rotor flux parameters; performing an inverse tangent calculation on the third rotor flux parameters to obtain the first electrical angle, and performing a differential calculation on the first electrical angle to obtain the first electrical angular velocity.

[0061] The preset rotor flux parameters of the motor may be the default flux parameters of the motor, or may be the real flux parameters obtained by actually measuring the permanent magnets in the motor. αβ And voltage value U αβ Afterwards, state variables and input variables are constructed, and the estimated rotor flux parameters are calculated by the nonlinear flux observer. The estimated rotor flux parameters are subtracted from the preset rotor flux parameters to obtain the compensation term, and the estimated rotor flux parameters are corrected using the compensation term to make them close to the preset rotor flux parameters. After continuous compensation, the third rotor flux parameters output by the nonlinear flux observer will approach the preset rotor flux parameters.

[0062] Specifically, the process of obtaining the third rotor flux parameter may include:

[0063] Step 1: construct state variables and input variables based on current value, voltage value and preset rotor flux parameters, where the mathematical expression of the state variable is:

[0064]

[0065] Among them, i α is the current value of the motor under the α axis, i β is the current value of the motor under the β axis, L s is the synchronous inductance of the motor, ψ f is the preset rotor flux parameter, θ e is the electrical angle of the motor;

[0066] The mathematical expression of the input variables is:

[0067]

[0068] Among them, u α is the voltage value of the motor under the α axis, u β is the voltage value of the motor under the β axis, R s is the stator resistance;

[0069] Step 2: Determine the third rotor flux parameter based on the state variable, the input variable and the nonlinear flux observer, wherein the mathematical expression of the nonlinear flux observer is:

[0070]

[0071] Where p is the differential operator, γ is the observer gain, is the estimated value of the state variable, is the third rotor flux parameter, and the mathematical expression of η(x) is:

[0072]

[0073] As an example, see Figure 2 ,like Figure 2 As shown, when obtaining the current value i αβ And voltage value U αβ After that, the current value i αβ And voltage value U αβ Input the nonlinear flux observer 203 to obtain the third rotor flux parameter output by the nonlinear flux observer 203

[0074] As an example, the observation process of the nonlinear flux observer 203 can be found in Figure 3 , Figure 3 is a structural block diagram of a nonlinear flux observer according to an embodiment of the present application. Figure 3 As shown, the nonlinear flux observer 203 can be based on the current value i αβ And voltage value U αβ , and the coordinate equations in the two-phase stationary coordinate system to construct the input variable y = U αβ -R s i αβ (It can also be shown as ); Then, according to the coordinate equation in the two-phase stationary coordinate system, it can be known that by integrating the input variable y, the state variable That is, px=y always holds.

[0075] Among them, the mathematical expression of the coordinate equation in the two-phase stationary coordinate system is:

[0076]

[0077] Among them, R s is the stator resistance, L s is the synchronous inductance of the motor, ψ f is the preset rotor flux parameter, θ e is the electrical angle of the motor.

[0078] Since integration will bring about the problem of DC bias, it is necessary to construct a nonlinear flux observer 203 to solve it. The mathematical expression of the nonlinear flux observer 203 is: It can be concluded from the mathematical expression of the nonlinear flux observer 203 that the nonlinear flux observer 203 compensates y by making a difference between the preset rotor flux parameters and the estimated rotor flux parameters, thereby offsetting the DC bias caused by the integral. After continuous compensation by the nonlinear flux observer 203, it will eventually make Approaching That is, the third rotor flux parameter output by the nonlinear flux observer 203 is will approach the preset rotor flux parameter ψ f.

[0079] When obtaining the third rotor flux parameters After that, the first electrical angle can be obtained by performing an inverse tangent on it. like Figure 2 As shown, the third rotor flux parameter Input the inverse tangent unit 205 to obtain the first electrical angle output by the inverse tangent unit 205 Among them, the first electrical angle The mathematical expression is:

[0080]

[0081] Then, for the first electrical angle Differentiate to get the first electrical angular velocity like Figure 2 As shown, the first electrical angle Input the differential unit 206 to obtain the first electrical angular velocity output by the differential unit 206 Among them, the first electrical angular velocity The mathematical expression is:

[0082]

[0083] Step S102: when the first electrical angular velocity is greater than a preset threshold, the current value, the voltage value and the first electrical angular velocity are input into a sliding film flux observer to obtain a first rotor flux parameter.

[0084] like Figure 2 As shown, the current value i can be obtained αβ And voltage value U αβ , and the first electrical angular velocity Afterwards, these parameters are input into the synovial flux observer 204 to obtain the first rotor flux parameter output by the synovial flux observer 204.

[0085] Since the observation effect of the nonlinear flux observer 203 depends on the given preset rotor flux parameter ψ f , the preset rotor flux parameter ψ fGenerally, the rotor flux parameters are obtained by actual measurement of the permanent magnets in the motor, but there are errors in the measured rotor flux parameters, and the permanent magnets are affected by temperature during operation. The rotor flux parameters of the permanent magnets will demagnetize with the increase of temperature, and the amplitude will decrease. Moreover, this relationship has a strong nonlinear characteristic and is difficult to correct by temperature detection. The error of the rotor flux parameter will affect the effect of the nonlinear flux observer 203, resulting in deviations in the electrical angle and electrical angular velocity finally obtained, thereby reducing the accuracy of the vector control of the motor. Therefore, the sliding film flux observer 204 can be used to observe the rotor flux parameters of the permanent magnet in real time, and the rotor flux parameters input to the nonlinear flux observer 203 can be adjusted in real time, so as to avoid the reduction of the accuracy of the vector control of the motor due to changes in the rotor flux parameters caused by temperature changes, measurement errors, etc.

[0086] In this embodiment, the current value, the voltage value and the first electrical angular velocity are input into the sliding film flux observer to obtain the first rotor flux parameter, which may include:

[0087] Step 1: Input the current value and voltage value into the sliding film flux observer to obtain the current observation error.

[0088] Step 2, based on the current observation error and the preset synovial arrival condition, determine the observation components of the back electromotive force generated by the permanent magnet in the motor under the α-axis and β-axis of the two-phase stationary coordinate system.

[0089] Step 3: Determine a first rotor flux parameter based on the observed component and the first electrical angular velocity, wherein the mathematical expression of the first rotor flux parameter is:

[0090]

[0091] in, is the first rotor flux parameter, ω e is the first electrical angular velocity, is the observed component of the back electromotive force generated by the permanent magnet under the α axis, is the observed component of the back electromotive force generated by the permanent magnet under the β axis.

[0092] The first rotor flux parameter It can be seen from the mathematical expression that when the motor static speed is 0, the estimated first rotor flux parameter will be infinite. Therefore, it is necessary to estimate the rotor flux parameter after the motor speed reaches a certain value and stabilizes.

[0093] Therefore, the first electrical angular velocity of the motor can be obtained. When the first electrical angular velocity of the motor is greater than a preset threshold and the time period in which the first electrical angular velocity is greater than the preset threshold exceeds the preset time period, the sliding film flux observer is used to observe the rotor flux parameters of the permanent magnet in real time.

[0094] It should be noted that since there are many types and application scenarios of electric vehicles, and there are also many models of permanent magnet synchronous motors used in electric vehicles, the above-mentioned preset thresholds and preset time periods should be determined based on the type and application scenario of the electric vehicle to which the electric vehicle motor vector control method provided in the embodiment of the present application is to be applied, as well as the model of the permanent magnet synchronous motor to be used. This application does not impose any restrictions on this.

[0095] For details, see Figure 4 , Figure 4 is a structural block diagram of a sliding film flux observer according to an embodiment of the present application, such as Figure 4 As shown, first, a sliding film flux observer can be pre-built, where the mathematical expression of the sliding film flux observer is:

[0096]

[0097] in, is the observed current value of the motor under the α axis, is the observed current value of the motor under the β axis, z α and z β is the synovial control function, R s is the stator resistance, L s is the synchronous inductance of the motor, u α is the voltage value of the motor under the α axis, u β is the voltage value of the motor under the β axis;

[0098] Secondly, the synovial switching surface can be selected, where the mathematical expression of the synovial switching surface is:

[0099]

[0100] Among them, i α is the current value of the motor under the β axis, α β is the current value of the motor under the β axis;

[0101] Again, the synovial control function can be determined, wherein the mathematical expression of the synovial control function is:

[0102]

[0103] Among them, k is the sign function coefficient, sgn is the sign function, and the expression of the sign function is as follows:

[0104]

[0105] Then, the current observation error can be calculated based on the sliding film flux observer, the sliding film switching surface and the sliding film control function, where the mathematical expression of the current observation error is:

[0106]

[0107] Among them, e α is the component of the back electromotive force generated by the permanent magnet under the α axis, e β is the component of the back electromotive force generated by the permanent magnet under the β axis.

[0108] Then, based on the current observation error and the preset sliding membrane arrival condition It can be determined that when k≥max|e α ,e β |, you can reach the synovial surface, then there are:

[0109]

[0110] From the mathematical expression of the synovial control function, we can know that z α 、z β It is a high frequency switching signal, therefore, it is necessary to α 、e β Performing a first-order low-pass filter, we can finally obtain the observed components of the back electromotive force generated by the permanent magnet in the motor under the α-axis and β-axis of the two-phase stationary coordinate system. Among them, the mathematical expression of the first-order low-pass filter is:

[0111]

[0112] Among them, ω c is the cutoff frequency of the first-order low-pass filter.

[0113] Finally, obtain the observed components of the back electromotive force generated by the permanent magnet in the motor under the α-axis and β-axis of the two-phase stationary coordinate system After that, the first rotor flux parameter can be calculated

[0114] In one embodiment, when the first electrical angular velocity is less than a preset threshold, the first electrical angle and the first electrical angular velocity A double closed-loop control system is input to enable the double closed-loop control system to perform vector control on the motor.

[0115] As an example, see Figure 2 ,like Figure 2 As shown, the motor speed setting value ω e_ref With the first electrical angular velocity The difference is input into the speed loop PI control unit 207, and the expected current value i of the motor under the q axis of the two-phase rotating coordinate system output by the speed loop PI control unit 207 is obtained. q_ref Among them, the speed loop PI control unit adopts a PI controller, and its control purpose is to control the motor speed so that the actual motor speed can quickly follow the given speed. It is the outer loop part of the double closed-loop control system and needs to meet the requirements of fast speed regulation and steady speed.

[0116] Then, the expected current value i q_ref The actual current value i of the motor under the q axis of the two-phase rotating coordinate system fed back by the Park transformation unit 202 q The difference is input into the first current loop PI control unit 208, and the voltage reference value U of the motor under the q axis of the two-phase rotating coordinate system output by the first current loop PI control unit 208 is obtained. q Similar to the above steps, based on the Park transformation unit 202 and the second current loop PI control unit 208, the voltage reference value U of the motor under the d-axis of the two-phase rotating coordinate system can be obtained. d Among them, the current loop PI control unit adopts a PI controller, and its control purpose is to control the motor current so that the three-phase current value i of the motor abc The current i in the two-phase rotating coordinate system obtained by coordinate transformation d 、i q The current expected value that can follow the speed loop PI control unit 207 outputs is the inner loop part in the double closed-loop control system and needs to meet the requirements of fast response and small current fluctuation.

[0117] Then, the voltage reference value U d , U q The inverse Park transformation unit 210 converts the voltage reference value U of the motor under the two-phase stationary coordinate axis into α , U β ; Space vector pulse width modulation 211 for voltage reference value U α , U β The PWM wave is modulated and the PWM wave controls the six switching devices of the inverter 212 so that the DC power supply signal is inverted into a three-phase AC voltage, thereby performing vector control on the motor 200 .

[0118] Step S103: input the current value, the voltage value and the first rotor flux parameter into a nonlinear flux observer to obtain the second rotor flux parameter.

[0119] It should be noted that the specific acquisition process of the second rotor flux parameters is similar to that of the third rotor flux parameters. The only difference is that to obtain the second rotor flux parameters, it is necessary to input the first rotor flux parameters into the parameters of the nonlinear flux observer, while to obtain the third rotor flux parameters, it is necessary to input the preset flux parameters into the parameters of the nonlinear flux observer. Therefore, the specific acquisition process of the second rotor flux parameters can refer to the above description of the third rotor flux parameters, and this application will not go into details here.

[0120] Step S104, performing an inverse tangent calculation on the second rotor flux parameter to obtain a target electrical angle, and performing a differential calculation on the target electrical angle to obtain a target electrical angular velocity.

[0121] It should be noted that the specific acquisition process of the target electrical angle and the target electrical angular velocity is similar to that of the first electrical angle and the first electrical angular velocity. Therefore, the specific acquisition process of the target electrical angle and the target electrical angular velocity can refer to the above description of the first electrical angle and the first electrical angular velocity, and this application will not go into details here.

[0122] Step S105 , inputting the target electrical angle and the target electrical angular velocity into the dual closed-loop control system, so that the dual closed-loop control system performs vector control on the motor.

[0123] It should be noted that the vector calculation can be performed in the timer interrupt, and the specific process of the vector control in step S105 can refer to the above embodiment of inputting the first electrical angle and the first electrical angular velocity into the dual closed-loop control system for vector control, which is not elaborated in this application.

[0124] Through the above steps S101 to S105, by acquiring various parameters of the motor in real time when the electric vehicle is running, when the speed of the motor is greater than a preset threshold, a sliding film flux observer is used to observe the current flux parameters of the motor, instead of directly inputting the default flux parameters of the motor (or the actual flux parameters of the permanent magnet in the motor obtained by measurement) into the nonlinear flux observer, it is possible to avoid the measurement error of the default flux parameters or the inconsistency between the default flux parameters and the current flux parameters caused by the demagnetization phenomenon generated during the operation of the permanent magnet. The impact on the observation accuracy of the nonlinear flux observer can be avoided, thereby improving the robustness of the motor control system; then, the current flux parameters observed by the sliding film flux observer are input into the nonlinear flux observer, and the nonlinear flux observer is used to observe the position and speed of the motor in a mechanical sensorless manner, thereby avoiding the defects of high cost, increased motor design complexity, reduced vector control accuracy, etc. caused by the use of mechanical sensors, and achieving real-time high-precision detection of the position of the motor rotor, thereby improving the accuracy of the vector control of the motor. Through the present application, the problem of low accuracy of vector control of the motor is solved, and the technical effect of improving the accuracy of vector control of the motor is achieved.

[0125] Corresponding to the electric vehicle motor vector control method described in the above embodiment, Figure 5 A schematic structural diagram of an electric vehicle motor control device according to an embodiment of the present application is shown. For ease of explanation, only the parts related to the embodiment of the present application are shown.

[0126] See also Figure 5 The electric vehicle motor control device 5 is used to control the motor in a two-wheel electric vehicle or a three-wheel electric vehicle. The electric vehicle motor control device 5 includes: an acquisition module 50, which is used to acquire the current value and voltage value of the motor, and the first electrical angular velocity of the motor when the electric vehicle is running; a first observation module 51, which is used to input the current value, voltage value and first electrical angular velocity into a sliding film flux observer when the first electrical angular velocity is greater than a preset threshold value to obtain a first rotor flux parameter; a second observation module 52, which inputs the current value, voltage value and first rotor flux parameter into a nonlinear flux observer to obtain a second rotor flux parameter; a calculation module 53, which is used to perform an inverse tangent calculation on the second rotor flux parameter to obtain a target electrical angle, and perform a differential calculation on the target electrical angle to obtain a target electrical angular velocity; a control module 54, which is used to input the target electrical angle and the target electrical angular velocity into a dual closed-loop control system so that the dual closed-loop control system performs vector control on the motor.

[0127] In one embodiment, the first observation module 51 is further used to input the current value and the voltage value into the sliding film flux observer to obtain the current observation error; based on the current observation error and the preset sliding film arrival condition, determine the observation component of the back electromotive force generated by the permanent magnet in the motor under the α-axis and β-axis of the two-phase stationary coordinate system; based on the observation component and the first electrical angular velocity, determine the first rotor flux parameter, wherein the mathematical expression of the first rotor flux parameter is:

[0128]

[0129] in, is the first rotor flux parameter, ω e is the first electrical angular velocity, is the observed component of the back electromotive force generated by the permanent magnet under the α axis, is the observed component of the back electromotive force generated by the permanent magnet under the β axis.

[0130] In one embodiment, the first observation module 51 is further used to pre-build a synovial flux observer, wherein the mathematical expression of the synovial flux observer is:

[0131]

[0132] in, is the observed current value of the motor under the α axis, is the observed current value of the motor under the β axis, z α and z β is the synovial control function, R s is the stator resistance, L s is the synchronous inductance of the motor, u α is the voltage value of the motor under the α axis, u β is the voltage value of the motor under the β axis; select the sliding film switching surface, where the mathematical expression of the sliding film switching surface is:

[0133]

[0134] Among them, i α is the current value of the motor under the α axis, i β is the current value of the motor under the β axis; determine the synovial control function, where the mathematical expression of the synovial control function is:

[0135]

[0136] Among them, k is the sign function coefficient, sgn is the sign function, and the expression of the sign function is as follows:

[0137]

[0138] Based on the sliding film flux observer, the sliding film switching surface and the sliding film control function, the current observation error is calculated, where the mathematical expression of the current observation error is:

[0139]

[0140] Among them, e α is the component of the back electromotive force generated by the permanent magnet under the α axis, e β is the component of the back electromotive force generated by the permanent magnet under the β axis.

[0141] In one embodiment, the acquisition module 50 is also used to obtain the current value, the voltage value and the preset rotor flux parameters of the motor; the second observation module 52 is also used to input the current value, the voltage value and the preset rotor flux parameters into the nonlinear flux observer to obtain the third rotor flux parameters; the calculation module 53 is also used to perform an inverse tangent calculation on the third rotor flux parameter to obtain the first electrical angle, and perform a differential calculation on the first electrical angle to obtain the first electrical angular velocity.

[0142] In one embodiment, the second observation module 52 is further used to construct state variables and input variables based on the current value, the voltage value and the preset rotor flux parameter, wherein the mathematical expression of the state variable is:

[0143]

[0144] Among them, iα is the current value of the motor under the α axis, i β is the current value of the motor under the β axis, L s is the synchronous inductance of the motor, ψ f is the preset rotor flux parameter, θ e is the electrical angle of the motor; the mathematical expression of the input variable is:

[0145]

[0146] Among them, u α is the voltage value of the motor under the α axis, u β is the voltage value of the motor under the β axis, R s is the stator resistance; based on the state variables, the input variables and the nonlinear flux observer, the third rotor flux parameter is determined, wherein the mathematical expression of the nonlinear flux observer is:

[0147]

[0148] Where p is the differential operator, γ is the observer gain, is the estimated value of the state variable, is the third rotor flux parameter, and the mathematical expression of η(x) is:

[0149]

[0150] In one embodiment, the control module 54 is further configured to input the first electrical angle and the first electrical angular velocity into the dual closed-loop control system when the first electrical angular velocity is less than a preset threshold, so that the dual closed-loop control system performs vector control on the motor.

[0151] In one embodiment, the current value and the voltage value are the current value and the voltage value of the motor in a two-phase stationary coordinate system; the acquisition module 50 is also used to obtain the three-phase current value and the three-phase voltage value of the motor; and the three-phase current value and the three-phase voltage value are converted into the current value and the voltage value of the motor in a two-phase stationary coordinate system using Clark transformation.

[0152] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0153] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0154] Figure 6 is a schematic diagram of the structure of an electric vehicle according to an embodiment of the present application. Figure 6 As shown, the electric vehicle 6 includes: at least one processor 60 ( Figure 6 Only one is shown in the figure) a processor, a memory 61, and a computer program 62 stored in the memory 61 and executable on at least one processor 60. When the processor 60 executes the computer program 62, the steps in any of the above-mentioned embodiments of the electric vehicle motor vector control method are implemented.

[0155] The electric vehicle 6 may include but is not limited to a processor 60 and a memory 61. It is understood by those skilled in the art that Figure 6 This is only an example of the electric vehicle 6 and does not constitute a limitation on the electric vehicle 6 . The electric vehicle 6 may include more or fewer components than shown in the figure, or a combination of certain components, or different components, for example, it may also include input and output devices, network access devices, etc.

[0156] The processor 60 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0157] In some embodiments, the memory 61 may be an internal storage unit of the electric vehicle 6, such as a hard disk or memory of the electric vehicle 6. In other embodiments, the memory 61 may also be an external storage device of the electric vehicle 6, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electric vehicle 6. In other embodiments, the memory 61 may also include both an internal storage unit and an external storage device of the electric vehicle 6. The memory 61 is used to store an operating system, an application program, a boot loader (BootLoader), data, and other programs, such as program codes of a computer program 62. The memory 61 may also be used to temporarily store data that has been output or is to be output.

[0158] The embodiment of the present application also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it can implement the steps in the above-mentioned embodiments of the electric vehicle motor vector control method.

[0159] An embodiment of the present application provides a computer program product. When the computer program product is run on a mobile terminal, the mobile terminal can implement the steps in the above-mentioned embodiments of the electric vehicle motor vector control method when executing the computer program product.

[0160] The present application implements all or part of the processes in the above-mentioned embodiment method, and can instruct the relevant hardware to complete through a computer program, and the computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of each of the above-mentioned method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may at least include: any entity or device capable of carrying the computer program code to an electric vehicle, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electric carrier signal, a telecommunication signal, and a software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk.

[0161] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0162] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of 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.

[0163] In the embodiments provided in the present application, it should be understood that the disclosed devices / network equipment and methods can be implemented in other ways. For example, the device / network equipment embodiments described above are only schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0164] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0165] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for vector control of an electric vehicle motor, characterized in that: The method comprises: When the electric vehicle is running, obtaining a current value and a voltage value of the motor, and a first electrical angular velocity of the motor; When the first electrical angular velocity is greater than a preset threshold, the current value, the voltage value and the first electrical angular velocity are input into a sliding film flux observer to obtain a first rotor flux parameter; Inputting the current value, the voltage value and the first rotor flux parameter into a nonlinear flux observer to obtain a second rotor flux parameter; Performing an inverse tangent calculation on the second rotor flux parameter to obtain a target electrical angle, and performing a differential calculation on the target electrical angle to obtain a target electrical angular velocity; The target electrical angle and the target electrical angular velocity are input into a dual closed-loop control system so that the dual closed-loop control system performs vector control on the motor.

2. The method according to claim 1, characterized in that Inputting the current value, the voltage value and the first electrical angular velocity into a sliding film flux observer to obtain a first rotor flux parameter includes: Inputting the current value and the voltage value into the sliding film flux observer to obtain a current observation error; Based on the current observation error and the preset synovial arrival condition, determining the observation components of the back electromotive force generated by the permanent magnet in the motor under the α-axis and the β-axis of the two-phase stationary coordinate system; Based on the observed component and the first electrical angular velocity, the first rotor flux parameter is determined, wherein the mathematical expression of the first rotor flux parameter is: in, is the first rotor flux parameter, ω e is the first electrical angular velocity, is the observed component of the back electromotive force generated by the permanent magnet under the α axis, is the observed component of the back electromotive force generated by the permanent magnet under the β axis.

3. The method according to claim 2, characterized in that The current value and the voltage value are input into the sliding film flux observer to obtain the current observation error, which includes: The sliding film flux observer is pre-constructed, wherein the mathematical expression of the sliding film flux observer is: in, is the observed current value of the motor under the α axis, is the observed current value of the motor under the β axis, z α and z β is the synovial control function, R s is the stator resistance, L s is the synchronous inductance of the motor, u α is the voltage value of the motor under the α axis, u β is the voltage value of the motor under the β axis; Select a synovial switching surface, wherein the mathematical expression of the synovial switching surface is: Among them, i α is the current value of the motor under the α axis, i β is the current value of the motor under the β axis; Determine the synovial control function, wherein the mathematical expression of the synovial control function is: Wherein, k is the sign function coefficient, sgn is the sign function, and the expression of the sign function is as follows: Based on the sliding film flux observer, the sliding film switching surface and the sliding film control function, the current observation error is calculated, wherein the mathematical expression of the current observation error is: Among them, e α is the component of the back electromotive force generated by the permanent magnet under the α axis, e β is the component of the back electromotive force generated by the permanent magnet under the β axis.

4. The method according to any one of claims 1 to 3, characterized in that Acquiring the current value and the voltage value of the motor, and the first electrical angular velocity of the motor includes: Acquiring the current value, the voltage value and a preset rotor flux parameter of the motor; Inputting the current value, the voltage value and the preset rotor flux parameter into the nonlinear flux observer to obtain a third rotor flux parameter; An inverse tangent calculation is performed on the third rotor flux parameter to obtain a first electrical angle, and a differential calculation is performed on the first electrical angle to obtain the first electrical angular velocity.

5. The method according to claim 4, characterized in that Inputting the current value, the voltage value and the preset rotor flux parameter into the nonlinear flux observer to obtain the third rotor flux parameter includes: A state variable and an input variable are constructed based on the current value, the voltage value and the preset rotor flux parameter, wherein the mathematical expression of the state variable is: Among them, i α is the current value of the motor under the a axis, i β is the current value of the motor under the β axis, L s is the synchronous inductance of the motor, ψ f is the preset rotor flux parameter, θ e is the electrical angle of the motor; The mathematical expression of the input variable is: Among them, u α is the voltage value of the motor under the α axis, u β is the voltage value of the motor under the β axis, R s is the stator resistance; Based on the state variable, the input variable and the nonlinear flux observer, a third rotor flux parameter is determined, wherein the mathematical expression of the nonlinear flux observer is: Where p is the differential operator, γ is the observer gain, is the estimated value of the state variable, is the third rotor flux parameter, and the mathematical expression of η(x) is:

6. The method according to claim 4, characterized in that After acquiring the current value and the voltage value of the motor, and the first electrical angular velocity of the motor, the method further includes: When the first electrical angular velocity is less than a preset threshold, the first electrical angle and the first electrical angular velocity are input into the dual closed-loop control system, so that the dual closed-loop control system performs vector control on the motor.

7. The method according to any one of claims 1 to 3, characterized in that The current value and the voltage value are the current value and the voltage value of the motor in a two-phase stationary coordinate system; Obtaining the current value and voltage value of the motor includes: Obtaining three-phase current values ​​and three-phase voltage values ​​of the motor; The three-phase current value and the three-phase voltage value are converted into the current value and the voltage value of the motor in the two-phase stationary coordinate system using Clark transformation.

8. An electric vehicle motor control device, characterized in that: include: An acquisition module, used for acquiring a current value and a voltage value of the motor and a first electrical angular velocity of the motor when the electric vehicle is running; a first observation module, configured to input the current value, the voltage value, and the first electrical angular velocity into a sliding film flux observer to obtain a first rotor flux parameter when the first electrical angular velocity is greater than a preset threshold; a second observation module, inputting the current value, the voltage value and the first rotor flux parameter into a nonlinear flux observer to obtain a second rotor flux parameter; a calculation module, configured to perform an inverse tangent calculation on the second rotor flux parameter to obtain a target electrical angle, and perform a differential calculation on the target electrical angle to obtain a target electrical angular velocity; The control module is used to input the target electrical angle and the target electrical angular velocity into a dual closed-loop control system so that the dual closed-loop control system performs vector control on the motor.

9. An electric vehicle, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the electric vehicle motor vector control method according to any one of claims 1 to 7 is implemented.

10. A computer program product, characterized in that The invention comprises a computer program, and when the computer program is executed, the electric vehicle motor vector control method according to any one of claims 1 to 7 is executed.

Images