Feedforward compensation composite control method and speed regulation system for variable load electric vehicle speed regulation

Abstract

The present invention discloses a variable load electric vehicle speed regulation feedforward compensation composite control method and speed regulation system, which relates to the field of electric vehicle speed regulation control. The composite control method includes defining the difference between the angular velocity of the motor and the target angular velocity as the first system state; defining the difference between the electromagnetic torque of the motor and the damping torque at the target angular velocity as the second system state; establishing a speed regulation system mathematical model according to the first system state and the second system state; constructing a disturbance observer according to the speed regulation system mathematical model; constructing a composite control sliding surface according to the first system state, the second system state and the disturbance observer, and then constructing a composite controller. The present invention transforms the traditional permanent magnet synchronous motor control model into a state equation of the system error, which can effectively characterize the adaptability of the system state to the variable load condition, and solve the problem that the variable load condition affects the stability of the speed output in the existing electric vehicle speed regulation system.

Description

Technical Field

[0001] The invention relates to the technical field of electric vehicle speed regulation control, in particular to a variable load electric vehicle speed regulation feedforward compensation composite control method and a speed regulation system. Background Art

[0002] One of the core technologies of electric vehicles is its speed control system. The design and implementation of this system is directly related to the performance, efficiency and driving experience of the vehicle. Electric vehicles need to operate under various road conditions and weather conditions, such as steep slopes and slippery roads, which requires the speed control system to be able to adapt to these changes in real time; changes in vehicle load (such as carrying people or cargo) have a direct impact on the performance of the speed control system, and the system must be able to adjust its output according to the load.

[0003] Under rapidly changing road conditions and load conditions, the system needs to adjust quickly to maintain vehicle performance and stability, but state modeling control may take a long time to estimate and predict the system state, thus affecting the real-time performance of the system. Error modeling control can respond more quickly to changes in road and weather conditions. By directly monitoring the error between the speed of the electric vehicle and the driver's expected speed, the system can adjust the output of the motor in real time to adapt to various road conditions such as steep slopes and slippery roads. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is how to make the speed control system adapt to these changes in real time according to the changes in the electric vehicle load.

[0006] To solve the above technical problems, the first object of the present invention is to provide a variable load electric vehicle speed control feedforward compensation composite control method, which includes: defining the difference between the angular velocity of the motor in the electric vehicle speed control system and the target angular velocity as a first system state; defining the difference between the electromagnetic torque of the motor in the electric vehicle speed control system and the damping torque at the target angular velocity as a second system state; establishing a mathematical model of the electric vehicle speed control system according to the first system state and the second system state; constructing a disturbance observer according to the mathematical model of the electric vehicle speed control system for real-time observation and compensation of the electric vehicle load disturbance; constructing a feedforward compensation composite control sliding surface according to the first system state, the second system state and the disturbance observer, and then constructing a feedforward compensation composite controller.

[0007] As a preferred solution of the variable load electric vehicle speed control feedforward compensation composite control method of the present invention, wherein: the electric vehicle speed control system includes a permanent magnet synchronous motor, and the mathematical model of the permanent magnet synchronous motor is:

[0008] ,

[0009] ,

[0010] ,

[0011] in, is the mechanical angular velocity of the motor; is the first-order differential of the motor's mechanical angular velocity; J is the rotor's moment of inertia; P n Pole pairs; is the magnetic link; i q is the q-axis current; B is the viscous damping coefficient; is the electromagnetic torque; T L is the load torque; i d is the d-axis current; is the first-order differential of the d-axis current; L d is the d-axis inductance; R is the stator resistance of the motor; L q is the q-axis inductance; is the d-axis voltage; is the first-order differential of the q-axis current; is the q-axis voltage.

[0012] As a preferred solution of the variable load electric vehicle speed regulation feedforward compensation composite control method of the present invention, wherein: the first system state is defined as e1, then:

[0013] ,

[0014] Define the second system state as e2, then:

[0015] ,

[0016] Based on the mathematical model of the permanent magnet synchronous motor, let i d =0, then the mathematical model of the electric vehicle speed control system is:

[0017] ,

[0018] ,

[0019] in, is the target angular velocity of the motor.

[0020] As a preferred solution of the variable load electric vehicle speed regulation feedforward compensation composite control method of the present invention, wherein: the first system state is defined as e1, then:

[0021] ,

[0022] Define the second system state as e2, then:

[0023] ,

[0024] Based on the mathematical model of the permanent magnet synchronous motor, let i d =0, then the mathematical model of the electric vehicle speed control system is:

[0025] ,

[0026] ,

[0027] in, is the target angular velocity of the motor.

[0028] As a preferred solution of the variable load electric vehicle speed regulation feedforward compensation composite control method of the present invention, wherein: under actual working conditions, , e 2 ∈ [ P n ψ f i q * − B ω * P n ψ f i q * + B ω * ] ,Right now e 2 ∈ [ min( e 2 ) max( e 2 ) ] , then the feedforward compensation composite control sliding surface of the electric vehicle speed regulation system is defined as:

[0029] ,

[0030] Among them, k1, k2, k3 are parameter adjustment gains, is the clipping boundary term, is the mismatched disturbance estimate, is the target q-axis current.

[0031] As a preferred solution of the variable load electric vehicle speed control feedforward compensation composite control method of the present invention, wherein: the feedforward compensation composite controller includes a reaching law, and the reaching law is defined as:

[0032] ,

[0033] in, is the exponential reaching law, It is a power reaching law.

[0034] As a preferred solution of the variable load electric vehicle speed regulation feedforward compensation composite control method of the present invention, the feedforward compensation composite controller model is:

[0035] ,

[0036] The feedforward compensation composite controller is used to adjust the q-axis voltage of the permanent magnet synchronous motor , so that the permanent magnet synchronous motor reaches the target angular velocity.

[0037] The second object of the present invention is to provide a variable load electric vehicle speed control system, which is based on the above-mentioned composite control valve method, including a system state definition module, which is used to define and calculate a first system state and a second system state; a mathematical model establishment module, which is used to receive the first system state and the second system state provided by the system state definition module, and establish an electric vehicle speed control system mathematical model based on a permanent magnet synchronous motor mathematical model; a disturbance observer module, which is used to receive the output of the electric vehicle speed control system mathematical model as input and construct a disturbance observer for real-time observation and compensation of electric vehicle load disturbances; a feedforward compensation composite control sliding surface construction module, which constructs a feedforward compensation composite control sliding surface according to the first system state, the second system state and the output of the disturbance observer, which is used to guide the behavior of the controller; a controller module, which generates a control input according to the feedforward compensation composite control sliding surface to adjust the state of the electric vehicle system so that it approaches the target state.

[0038] The third object of the present invention is to provide an electronic device, which includes a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned variable load electric vehicle speed regulation feedforward compensation composite control method when executing the computer program.

[0039] The fourth object of the present invention is to provide a computer-readable storage medium, characterized in that: it stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, the steps of the above-mentioned variable load electric vehicle speed regulation feedforward compensation composite control method are implemented.

[0040] The beneficial effects of the present invention are as follows: the present invention transforms the traditional permanent magnet synchronous motor control model into a state equation of system error, which can effectively characterize the adaptability of the system state to variable load conditions and solve the stability problem of the existing electric vehicle speed control system in which variable load conditions affect the speed output. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 This is a flow chart of the feedforward compensation composite control method for the variable load electric vehicle speed regulation system described in Example 1 of the present invention.

[0043] Figure 2This is a load torque diagram of the feedforward compensation composite control method for the variable load electric vehicle speed regulation system described in Example 2 of the present invention.

[0044] Figure 3 This is a speed tracking diagram of the simulation results of the feedforward compensation composite control method for the variable load electric vehicle speed regulation system described in Example 2 of the present invention.

[0045] Figure 4 This is an error diagram of the simulation results of the feedforward compensation composite control method for the variable load electric vehicle speed regulation system described in Example 2 of the present invention. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0047] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0048] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive with other embodiments, either individually or selectively.

[0049] Example 1, reference Figure 1 , which is the first embodiment of the present invention, and which provides a variable load electric vehicle speed regulation feedforward compensation composite control method, the variable load electric vehicle speed regulation feedforward compensation composite control method comprises:

[0050] S1: Define the difference between the angular velocity of the motor and the target angular velocity in the electric vehicle speed control system as the first system state.

[0051] In this embodiment, the motor in the electric vehicle speed control system is a permanent magnet synchronous motor, so the first system state is defined as e1, then:

[0052] ,

[0053] in, is the mechanical angular velocity of the permanent magnet synchronous motor, is the target angular velocity of the permanent magnet synchronous motor.

[0054] S2: The difference between the electromagnetic torque of the motor in the electric vehicle speed control system and the damping torque at the target angular velocity is defined as the second system state.

[0055] It should be noted that the second system state is a polynomial about the q-axis current variable of the permanent magnet synchronous motor current loop, so the second system state is defined as e2, then:

[0056] ,

[0057] in, is the electromagnetic torque of the permanent magnet synchronous motor, B is the viscous damping coefficient of the permanent magnet synchronous motor, is the target angular velocity of the permanent magnet synchronous motor, is the damping torque at the target angular velocity of the permanent magnet synchronous motor.

[0058] S3: Establishing a mathematical model of the electric vehicle speed control system according to the first system state e1 and the second system state e2.

[0059] It should be noted that the mathematical model of the electric vehicle speed control system is based on the mathematical model of the permanent magnet synchronous motor, which is:

[0060] ,

[0061] ,

[0062] ,

[0063] in, is the mechanical angular velocity of the motor, representing the rotation speed of the motor rotor; is the first-order differential of the motor's mechanical angular velocity; J is the rotor's moment of inertia, which affects the motor's response to speed changes; P n Pole pairs; is the magnetic link; i q is the q-axis current, which represents the current passing through the q-axis of the motor; B is the viscous damping coefficient, which describes the resistance in the movement of the motor; is the electromagnetic torque; T L is the load torque, the external load that the motor needs to overcome; i d is the d-axis current, representing the current passing through the d-axis of the motor; is the first-order differential of the d-axis current; L d is the d-axis inductance, which characterizes the electromagnetic induction capability of the motor’s d-axis; R is the stator resistance of the motor, which affects the energy consumption and heat loss of the motor; L q is the q-axis inductance, which represents the electromagnetic induction capability of the motor’s q-axis; is the d-axis voltage, the voltage applied by the inverter on the d-axis; is the first-order differential of the q-axis current; is the q-axis voltage, which is the voltage applied by the inverter on the q-axis.

[0064] According to the first system state e1 and the second system state e2, let i d =0, then the mathematical model of the electric vehicle speed control system is:

[0065] ,

[0066] ,

[0067] in, is the target angular velocity of the motor.

[0068] S4: A disturbance observer is constructed based on the mathematical model of the electric vehicle speed control system to perform real-time observation and compensation of the electric vehicle load disturbance.

[0069] It should be noted that variable load conditions refer to the various load changes that electric vehicles encounter during driving, such as acceleration, deceleration, climbing, descending, changes in vehicle load, etc. When the load of an electric vehicle changes, T is defined as L For uncertain load,

[0070] make x = [ e 1 e 2 ] T , then the mathematical model of the electric vehicle speed control system can be transformed into:

[0071] ,

[0072] in, f ( x ) = [ 1 J ( e 2 − Be 1 ) 1 L q ( − R ( e 2 + B ω * ) − ( P n ψ f ) 2 ( e 1 + ω * ) ) ] T , g 1 = [ 0 P n ψ f L q ] T , g 2 = [ − 1 J 0 ] T ;

[0073] Then the disturbance observer can be defined as:

[0074] ,

[0075] ,

[0076] in, For uncertain load T L The observed value, z is the intermediate state quantity of the disturbance observer, It is gain.

[0077] S5: construct a feedforward compensation composite control sliding surface according to the first system state, the second system state and the disturbance observer, and then construct a feedforward compensation composite controller.

[0078] Specifically, under actual working conditions, , e 2 ∈ [ P n ψ f i q * − B ω * P n ψ f i q * + B ω * ] ,Right now e 2 ∈ [ min( e 2 ) max( e 2 ) ] , then the feedforward compensation composite control sliding surface of the electric vehicle speed regulation system is defined as:

[0079] ,

[0080] Among them, k1, k2, k3 are parameter adjustment gains, is the clipping boundary term, is the mismatched disturbance estimate, is the target q-axis current.

[0081] Then, the reaching law is used in combination with the disturbance observer to design the feedforward compensation composite controller for the variable load electric vehicle speed control system. The reaching law includes the exponential reaching law and the power reaching law. Specifically,

[0082] The reaching law is defined as:

[0083] ,

[0084] in, is the exponential reaching law, It is a power reaching law.

[0085] Furthermore, the feedforward compensation composite controller model is:

[0086] ,

[0087] Feedforward compensation composite controller for regulating the q-axis voltage of permanent magnet synchronous motor ,Will The input is sent to the permanent magnet synchronous motor for speed regulation so that the permanent magnet synchronous motor reaches the target angular velocity. .

[0088] Furthermore, the stability of the above composite control method is proved:

[0089] Take the first-order differential of the sliding surface of the feedforward compensation composite control of the electric vehicle speed control system:

[0090] ,

[0091] Feedforward compensation composite controller for variable load electric vehicle speed control system Substituting into the above formula:

[0092] ,

[0093] Further:

[0094] ,

[0095] Assume the Lyapunov equation: ,

[0096] Further:

[0097] ,

[0098] Then the above formula is transformed into case 1:

[0099] ,

[0100] The above formula is transformed into the following situation 2:

[0101] ,

[0102] According to situation 1, , , , then the stability is satisfied.

[0103] According to cases 1 and 2, the state of the system converges asymptotically to the sliding mode surface of the feedforward compensation composite control of the electric vehicle speed regulation system, which is restricted to the neighborhood:

[0104] ;

[0105] ;

[0106] .

[0107] In this embodiment, the variable load electric vehicle speed control system includes:

[0108] A system state definition module, which is used to define and calculate a first system state and a second system state;

[0109] A mathematical model building module, used for receiving the first system state and the second system state provided by the system state definition module, and building a mathematical model of the electric vehicle speed control system based on the permanent magnet synchronous motor mathematical model;

[0110] A disturbance observer module, for receiving the output of the mathematical model of the electric vehicle speed control system as input and constructing a disturbance observer for real-time observation and compensation of the electric vehicle load disturbance;

[0111] A feedforward compensation composite control sliding surface construction module, which constructs a feedforward compensation composite control sliding surface according to the first system state, the second system state and the output of the disturbance observer, so as to guide the behavior of the controller;

[0112] The controller module generates control inputs according to the feedforward compensation composite control sliding surface to adjust the state of the electric vehicle system so that it approaches the target state.

[0113] This embodiment also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor is used to execute computer executable instructions to implement the variable load electric vehicle speed regulation feedforward compensation composite control method as described above.

[0114] This embodiment also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the variable load electric vehicle speed regulation feedforward compensation composite control method proposed in the above embodiment is implemented.

[0115] Example 2, reference Figure 2~Figure 4 , which is the second embodiment of the present invention, and is based on the previous embodiment. This embodiment provides a case for proving the feasibility of applying a variable load electric vehicle speed regulation feedforward compensation composite control method and a case for verifying the beneficial effects.

[0116] In order to verify and illustrate the technical effects adopted in the present invention, a surface-mounted three-phase permanent magnet synchronous motor is selected as the test target in this embodiment, and the control method proposed in the present invention is tested. The test results are compared by means of scientific demonstration to verify the real effect of the control method.

[0117] The test environment is as follows: the surface-mounted three-phase permanent magnet synchronous motor theoretical model is run on a simulation platform, 1000r / min is used as the tracking target, the control method proposed by the present invention and the traditional sliding mode method are used for testing, and comparative test results are obtained. The simulation test of the theoretical model is realized by turning on the automated test equipment and running MATLAB software programming, and the simulation data is obtained according to the experimental results.

[0118] The test parameters are: ; ; ; ; ; ; ; ; ; f ( x ) = [ 1 0 . 003 ( e 2 − 0 . 008 e 1 ) 1 8 . 5 ( − 2 . 875 ( e 2 + 24 ) − 0 . 49 ( e 1 + 3000 ) ) ] T ; g 1 = [ 0 0 . 7 8 . 5 ] T ; g 2 = [ − 1 0 . 003 0 ] T ; l = [ 3 0 ] ; ; ; ; ; ; ; ; .

[0119] Reference Figure 2 , is the load torque diagram of the feedforward compensation composite control method for the variable load electric vehicle speed control system. Figure 2 As shown, the designed variable load condition is: the load torque T at the initial moment L =0N·m; when the running time reaches 0.2s, the load torque T L =10N·m.

[0120] Reference Figure 3 , is the speed tracking diagram of the simulation result of the feedforward compensation composite control method for the variable load electric vehicle speed control system. Figure 3 As shown, curve 1 is the control method proposed by the present invention, and curve 2 is the traditional sliding mode method. Taking 1000r / min as the tracking target, curve 1 and curve 2 have the same response time, but curve 2 shows a larger overshoot of about 300r / min. In addition, for the variable load condition at 0.2s, curve 2 has poor anti-interference ability and low stability.

[0121] Reference Figure 4 , is the simulation result error diagram of the feedforward compensation composite control method for the variable load electric vehicle speed control system. Figure 4 As shown in the figure, based on the speed tracking diagram, the tracking error is further investigated. The error curve of the traditional control method shows large error fluctuations at the initial moment (about 0s) and the variable load moment (about 0.2s), indicating that the traditional control method cannot achieve high adaptability to variable load conditions.

[0122] According to the above test environment and parameter settings, the simulation results show that compared with the prior art, the present invention discloses a variable load electric vehicle speed control system feedforward compensation composite control method, which transforms the traditional control model based on the surface-mounted permanent magnet synchronous motor into a state equation of the system error, and can effectively characterize the adaptability of the system state to variable load conditions; the limiting boundary term is combined with the first system state and the second system state to design a feedforward compensation composite control, and the stability is proved, which proves the effectiveness of the designed method from theory and practice.

[0123] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A variable load electric vehicle speed regulation feedforward compensation composite control method, characterized in that: include, The difference between the angular velocity of the motor and the target angular velocity in the electric vehicle speed control system is defined as the first system state; The difference between the electromagnetic torque of the motor in the electric vehicle speed control system and the damping torque at the target angular velocity is defined as the second system state; Establishing a mathematical model of the electric vehicle speed control system according to the first system state and the second system state; A disturbance observer is constructed according to the mathematical model of the electric vehicle speed regulation system, which is used for real-time observation and compensation of the electric vehicle load disturbance; constructing a feedforward compensation composite control sliding surface according to the first system state, the second system state and the disturbance observer, and then constructing a feedforward compensation composite controller; The electric vehicle speed control system includes a permanent magnet synchronous motor, and the mathematical model of the permanent magnet synchronous motor is: Among them, ω m is the mechanical angular velocity of the motor; is the first-order differential of the motor's mechanical angular velocity; J is the rotor's moment of inertia; P n Pole pair number; ψ f is the magnetic link; i q is the q-axis current; B is the viscous damping coefficient; T e =P n ψ f i q is the electromagnetic torque; T L is the load torque; i d is the d-axis current; is the first-order differential of the d-axis current; L d is the d-axis inductance; R is the stator resistance of the motor; L q is the q-axis inductance; u d is the d-axis voltage; is the first-order differential of the q-axis current; u q is the q-axis voltage; Define the first system state as e1, then: e1=ω m -oh * Define the second system state as e2, then: e2=P n ψ f I q -Yes * Based on the mathematical model of the permanent magnet synchronous motor, let i d =0, then the mathematical model of the electric vehicle speed control system is: Among them, ω * is the target angular velocity of the motor; When the load of the electric vehicle changes, define T L For uncertain load, Let x = [e1e2] T , then the mathematical model of the electric vehicle speed control system can be transformed into: in, Then the disturbance observer can be defined as: in, For uncertain load T L The observed value, z is the intermediate state quantity of the disturbance observer, l∈R 2×1 is gain; In actual working conditions, |i q |<i q * , e2∈[P n ψ f i q * -Bω * P n ψ f i q * +Bω * ], that is, e2∈[min(e2) max(e2)], then the feedforward compensation composite control sliding surface of the electric vehicle speed regulation system is defined as: Among them, k1, k2, k3 are parameter adjustment gains, is the clipping boundary term, is the mismatched disturbance estimate, i q * is the target q-axis current; The feedforward compensation composite controller includes a reaching law, which is defined as: Among them, -k4s is the exponential approach law, -k5sig(s) γ It is a power reaching law; The feedforward compensation composite controller model is: The feedforward compensation composite controller is used to adjust the q-axis voltage u of the permanent magnet synchronous motor. q , so that the permanent magnet synchronous motor reaches the target angular velocity.

2. A variable load electric vehicle speed control system, characterized in that: The electric vehicle speed control system is based on the variable load electric vehicle speed control feedforward compensation composite control method as claimed in claim 1, comprising: A system state definition module, which is used to define and calculate a first system state and a second system state; A mathematical model building module, used for receiving the first system state and the second system state provided by the system state definition module, and building a mathematical model of the electric vehicle speed control system based on the permanent magnet synchronous motor mathematical model; A disturbance observer module, used for receiving the output of the mathematical model of the electric vehicle speed regulation system as input and constructing a disturbance observer for real-time observation and compensation of electric vehicle load disturbance; A feedforward compensation composite control sliding surface construction module, which constructs a feedforward compensation composite control sliding surface according to the first system state, the second system state and the output of the disturbance observer, so as to guide the behavior of the controller; The controller module generates a control input according to the feedforward compensation composite control sliding surface to adjust the state of the electric vehicle system so that it approaches the target state.

3. An electronic device, characterized in that: It comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the variable load electric vehicle speed regulation feedforward compensation composite control method as claimed in claim 1 are implemented.

4. A computer-readable storage medium, characterized in that: It stores computer executable instructions, which, when executed by a processor, implement the steps of the variable load electric vehicle speed regulation feedforward compensation composite control method as described in claim 1.

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