Dual-motor system torque distribution control method based on linear active disturbance rejection decoupling control

Abstract

The invention discloses a dual-motor system torque distribution control method based on linear active-disturbance-rejection decoupling control, and the method comprises the steps: building a decoupling model based on a total torque and a torque synchronization error through linear active-disturbance-rejection decoupling, and designing a torque following controller and a torque synchronization controller according to the decoupling model; wherein two linear extended state observers are used for observing disturbance in the torque synchronous controller; then controller parameters are determined according to the Bode diagram of the disturbance transfer function; and the output of the torque following controller and the output of the torque synchronous controller, namely following voltage and synchronous voltage, are superposed to obtain q-axis voltage of the two motors, so that the torque of the two motors is controlled. According to the invention, independent operation of total torque following and synchronous control of the torque of each motor can be realized, and good torque distribution is realized. When the load is changed, the motors are synchronous according to the torque of the output ratio; when the output proportion of each motor is adjusted, the output torque of the system is kept unchanged.

Description

Technical Field

[0001] The present invention belongs to the technical field of multi-motor control, and in particular is a torque distribution control method for a dual-motor system based on linear auto-disturbance rejection decoupling control. Background Art

[0002] Multi-motor drive systems play an increasingly important role in modern industrial and transportation systems due to their flexibility and reliability. In a multi-motor system, by adjusting the output ratio of each motor, the system performance can be optimized, such as reducing system energy consumption and eliminating gear backlash. The researchers used a model- or rule-based strategy to obtain the optimal output ratio of each motor in the system under different operating conditions, and achieved torque synchronization under the torque distribution by applying a torque-following-based torque distribution control method, thereby optimizing system performance. Torque distribution control lays the foundation for achieving optimal control of dual-motor systems and plays a vital role.

[0003] However, due to the different torque responses of different motors, the actual system cannot operate according to the preset torque distribution and cannot achieve the expected torque distribution. Torque distribution control can be decomposed into total torque following control and torque synchronization control. The coupling between the two will affect the torque distribution control performance. When adjusting the output ratio, the sudden change in total torque will cause a mismatch between the total torque and the load torque, affecting the stability of the system; when the external load changes, the two motors cannot operate according to the set output ratio.

[0004] The document with application number 201310497209.9 discloses a method for synchronous coordinated control of multiple motors, which realizes the reasonable distribution of loads among multiple motors through the master-slave control method. However, in the process of realizing torque distribution, this method completely relies on each motor to follow its own torque reference value. Affected by the difference in motor parameters, the torque following process of different motors is different, and it is difficult to accurately run synchronously according to the preset torque distribution scheme in actual operation. The document with application number 201610599177.7 discloses a method for torque balancing control of a dual-motor gear transmission system, which maintains the torque synchronization of each motor by means of torque cross-coupling. However, this method does not consider the need to adjust the output ratio of each motor in the system, and does not meet the application of dual-motor torque distribution control. Therefore, a torque distribution control method that can realize free adjustment of the motor output ratio and maintain a good torque synchronization effect is still a problem to be studied. Summary of the invention

[0005] In view of the deficiencies in the prior art, the technical problem that the present invention intends to solve is to provide a torque distribution control method for a dual-motor system based on linear auto-disturbance rejection decoupling control.

[0006] The technical solution of the present invention to solve the technical problem is to provide a dual-motor system torque distribution control method based on linear active disturbance rejection decoupling control, characterized in that the method comprises the following steps:

[0007] Step 1: Analyze the two motors as a whole and establish a torque synchronization error based on the total torque T and torque synchronization error T. Δ , q-axis following voltage u q and q-axis synchronous voltage u qΔ The decoupling model is shown in formula (1):

[0008]

[0009] In formula (1), b0 is the compensation factor; w and v are disturbances;

[0010] Step 2: According to the decoupling model, a torque following controller based on first-order linear anti-disturbance control is designed, eliminating the tracking differentiator link, and the given reference signal is the total torque reference value T output by the speed controller. ref , the output is the q-axis following voltage u q The observed quantities of the linear extended state observer of the torque following controller are the total torque T and the disturbance w in equation (1), and its input is the q-axis following voltage u q and total torque T;

[0011] According to the decoupling model, a torque synchronization controller based on first-order linear active disturbance rejection control is designed, eliminating the tracking differentiator link, and the given reference signal is the torque synchronization error reference value T Δref , the output is the q-axis synchronous voltage u qΔ , the feedback quantity is the torque synchronization error T Δ The observed value of the torque synchronization error T Δ Decomposed into the electromagnetic torque T of motor 1 e1 and the electromagnetic torque T of motor 2 e2 , decompose the disturbance v in equation (1) into two parts v1 and v2 belonging to motor 1 and motor 2, and use the bilinear extended state observer to obtain the torque synchronization error T Δ The observation value of and the observation value of disturbance v; the input of the bilinear extended state observer is the electromagnetic torque T of motor 1 e1 and the electromagnetic torque T of motor 2 e2 And the q-axis voltage u of motor 1 q1 and the q-axis voltage u of motor 2 q 2;

[0012] Step 3: Determine the linear extended state observer bandwidth ω0 of the torque following controller and the torque synchronization controller and the linear state error feedback control law gain K of the torque following controller through the Bode diagram of the disturbance transfer function. p1The linear state error feedback control law gain K of the torque synchronization controller p2 ;

[0013] Step 4: The q-axis following voltage u output by the torque following controller and the torque synchronization controller q and q-axis synchronous voltage u qΔ Get the q-axis voltage u of the two motors q1 and u q2 ; and then with their respective d-axis voltage u d The two motors are input into the modulation module of the motor control system to realize dual-motor torque distribution control.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) The present invention first uses linear anti-disturbance decoupling to establish a decoupling model based on total torque and torque synchronization error, and designs a torque following controller and a torque synchronization controller accordingly, wherein two linear extended state observers are used in the torque synchronization controller to observe disturbances; then the controller parameters are determined according to the Bode diagram of the disturbance transfer function; the outputs of the torque following controller and the torque synchronization controller, i.e., the following voltage and the synchronization voltage, are superimposed to obtain the q-axis voltage of the two motors, thereby realizing the control of the torque of the two motors. The present invention can realize the independent operation of total torque following and the synchronous control of the torque of each motor, and realize good torque distribution. When the load changes, the torque of each motor is synchronized according to the output ratio; when the output ratio of each motor is adjusted, the system output torque remains unchanged.

[0016] (2) The present invention decomposes torque control into total torque following control and torque synchronization control, and uses linear anti-disturbance control to achieve decoupling control of total torque and torque synchronization error, thereby achieving a good torque distribution effect.

[0017] (3) The present invention regards the two motors as a whole and directly performs closed-loop control on the total torque. It is able to freely adjust the output ratio of each motor and maintain good torque synchronization control. When changing the output ratio of each motor, it is ensured that the total torque output of the system does not change.

[0018] (4) The present invention achieves torque synchronization between the two motors by controlling the torque synchronization error between the two motors, thereby ensuring that the two motors operate strictly according to the set output ratio.

[0019] (5) In order to meet the need of adjusting the output ratio, the present invention decomposes the torque synchronization error and disturbance in the torque synchronization control into two parts that do not change suddenly, thereby obtaining accurate observation values ​​and realizing good torque synchronization control. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is a flow chart of the torque distribution control method of the dual-motor system based on linear auto-disturbance rejection decoupling control of the present invention;

[0021] Figure 2 It is a structural block diagram of the torque following controller of the present invention;

[0022] Figure 3 It is a structural block diagram of the torque synchronization controller of the present invention;

[0023] Figure 4 This is a schematic diagram of the gear transmission between the two motors in Embodiment 1 of the present invention;

[0024] Figure 5 is a Bode diagram of the disturbance transfer function in Example 1 of the present invention;

[0025] Figure 6 This is an experimental waveform diagram of Example 1 of the present invention when the output ratio of the two motors is 1:1 under variable load conditions using the existing master-slave control method;

[0026] Figure 7 This is an experimental waveform diagram of Example 1 of the present invention when the output ratio of the two motors is 1:1 under variable load conditions using the method of the present invention;

[0027] Figure 8 This is an experimental waveform diagram of the case where the output ratio of the two motors is 1:4 under variable load conditions using the existing master-slave control method in Example 1 of the present invention;

[0028] Fig. 9 This is an experimental waveform diagram of the method of the present invention in Example 1 of the present invention when the output ratio of the two motors is 1:4 under variable load conditions;

[0029] Fig.10 Experimental waveform diagram when the output ratio of the two motors changes from 1:1 to 1:4 using the existing master-slave control method in Example 1 of the present invention;

[0030] Fig.11 Experimental waveform diagram when the output ratio of the two motors changes from 1:1 to 1:4 using the method of the present invention in Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are given below. The specific embodiments are only used to further illustrate the present invention in detail and do not limit the protection scope of the present invention.

[0032] The present invention provides a dual-motor system torque distribution control method based on linear auto-disturbance rejection decoupling control (hereinafter referred to as the method), characterized in that the method comprises the following steps:

[0033] Step 1: To achieve linear active disturbance rejection control, the total torque T and torque synchronization error T ΔEffective decoupling is achieved by treating the two motors as a whole for analysis and establishing a torque synchronization error based on the total torque T and torque synchronization error T Δ , q-axis following voltage u q and q-axis synchronous voltage u qΔ The decoupling model is shown in formula (1):

[0034]

[0035] In formula (1), b0 is the compensation factor; w and v are disturbances;

[0036] Preferably, in step 1, the disturbance w, the disturbance v and the compensation factor b0 satisfy:

[0037]

[0038] In formula (2), b i =1.5pΨ fi / L i , i = 1 or 2, and the compensation factor b0 is calculated; a i =-1.5pΨ fi (R i i qi +ωL i i di +ωΨ fi ) / L i ; R i , L i and fi is the stator resistance, stator inductance and permanent magnet flux of motor i, p is the number of motor pole pairs; i qi is the q-axis current of motor i; ω is the speed of the two motors; i di is the d-axis current of motor i; Δb1 is the difference between b1 and compensation factor b0; Δb2 is the difference between b2 and compensation factor b0; u q1 、u q2 is the q-axis voltage of motor 1 and motor 2; k1 and k2 are the set output ratios of motor 1 and motor 2.

[0039] Preferably, in step 1, the total torque T and the torque synchronization error T Δ , q-axis following voltage u q and q-axis synchronous voltage u qΔ satisfy:

[0040]

[0041] In formula (3), T e1 , T e2 is the electromagnetic torque of motor 1 and motor 2; k1 and k2 are the output ratios of motor 1 and motor 2; u q1 、uq2 is the q-axis voltage of motor 1 and motor 2.

[0042] Step 2: According to the decoupling model, a torque following controller based on first-order linear anti-disturbance control is designed, eliminating the tracking differentiator link, and the given reference signal is the total torque reference value T output by the speed controller. ref , the output is the q-axis following voltage u q The observed quantities of the linear extended state observer (LESO) of the torque following controller are the total torque T and the disturbance w in equation (1), and its input is the q-axis following voltage u q and total torque T;

[0043] According to the decoupling model, a torque synchronization controller based on first-order linear active disturbance rejection control is designed, eliminating the tracking differentiator link, and the given reference signal is the torque synchronization error reference value T Δref , the output is the q-axis synchronous voltage u qΔ , the feedback quantity is the torque synchronization error T Δ The observed value of the torque synchronization error T Δ Decomposed into the electromagnetic torque T of motor 1 e1 and the electromagnetic torque T of motor 2 e2 , decompose the disturbance v in equation (1) into two parts v1 and v2 belonging to motor 1 and motor 2, and use the bilinear extended state observer to obtain the torque synchronization error T Δ The observation value of and the observation value of disturbance v; the input of the bilinear extended state observer is the electromagnetic torque T of motor 1 e1 and the electromagnetic torque T of motor 2 e2 And the q-axis voltage u of motor 1 q1 and the q-axis voltage u of motor 2 q 2;

[0044] Preferably, in step 2, the algorithm equation of the torque following controller (such as Figure 2 shown) is:

[0045]

[0046] In formula (4), · represents the derivative; ^ represents the observed value; A1 and A2 are the output error correction gains of the linear extended state observer, which are related to the bandwidth ω0 of the linear extended state observer, A1 = 2ω0, A2 = ω0 2 ; K p1 is the linear state error feedback control law (LSEF) gain of the torque following controller; u0 is the output of the linear state error feedback control law of the torque following controller.

[0047] Preferably, in step 2, the torque synchronization error T Δ and the disturbance v are each decomposed into two parts:

[0048]

[0049] In formula (5), v1 and v2 are the parts of disturbance v decomposed into motor 1 and motor 2 respectively.

[0050] Preferably, in step 2, for the torque synchronization controller, the disturbance v undergoes a sudden change due to the need to switch the motor output instantaneously, and the extended state observer cannot observe the instantaneous sudden change, so the traditional first-order linear anti-disturbance control structure is no longer applicable. However, when the compensation factors of the total torque following control and the torque synchronization control are the same, both b0, the observed values ​​calculated by motor 1 and motor 2 according to the compensation factor b0 satisfy the first and second terms of the disturbance v, so the purpose of accurate observation can be achieved by decomposing the torque ratio difference and the disturbance v; using the electromagnetic torque T of motor 1 e1 , electromagnetic torque T of motor 2 e2 , q-axis voltage u of motor 1 q1 and the q-axis voltage u of motor 2 q2 Directly observe the disturbance v, and directly use the set output ratios k1 and k2 to calculate the observed value of the disturbance v. Using the algorithm equation of the torque synchronization controller of the bilinear extended state observer (such as Figure 3 shown) is:

[0051]

[0052] In formula (6), · represents the derivative; ^ represents the observed value; A1 and A2 are the two linear extended state observer output error correction gains of the torque synchronization controller, which are the same as the linear extended state observer output error correction gain of the torque following controller; k1 and k2 are the output ratios set for motor 1 and motor 2; K p2 is the linear state error feedback control law gain of the torque synchronization controller; u0 is the output of the linear state error feedback control law of the torque synchronization controller, which is the same as the output of the linear state error feedback control law of the torque following controller.

[0053] Step 3: Determine the linear extended state observer bandwidth ω0 of the torque following controller and the torque synchronization controller and the linear state error feedback control law gain K of the torque following controller through the Bode diagram of the disturbance transfer function. p1 The linear state error feedback control law gain K of the torque synchronization controller p2 , enhance disturbance tracking capability and improve the system's disturbance suppression performance;

[0054] Preferably, in step 3, the idea of ​​self-disturbance rejection decoupling control is used. If the disturbance is fully compensated, the torque control loop is simplified to a first-order integral link. At this time, the total torque T and the torque synchronization error T ΔThe control of is independent of each other and does not affect each other. However, in practice, it is impossible to fully compensate for disturbances. The decoupling control effect of the system is related to the observation effect of the extended state observer and the gain of the state error feedback control law.

[0055] Preferably, in step 3, the disturbance transfer function of the torque follower controller, that is, the transfer function between the total torque T and the disturbance w is:

[0056]

[0057] In formula (7), s represents a complex number; A1 and A2 are the linear extended state observer output error correction gains of the torque following controller; K p1 is the linear state error feedback control law gain of the torque following controller.

[0058] Preferably, in step 3, the disturbance transfer function of the torque synchronization controller, that is, the torque synchronization error T Δ The transfer function between and the disturbance v is:

[0059]

[0060] In formula (8), s represents a complex number; A1 and A2 are the output error correction gains of the two linear extended state observers of the torque synchronization controller; K p2 is the linear state error feedback control law gain of the torque synchronization controller.

[0061] Step 4: The q-axis following voltage u output by the torque following controller and the torque synchronization controller q and q-axis synchronous voltage u qΔ Get the q-axis voltage u of the two motors q1 and u q2 ; and then with their respective d-axis voltage u d The two motors are input into the modulation module of the existing motor control system to realize dual-motor torque distribution control.

[0062] Preferably, in step 4, the q-axis follows the voltage u q and q-axis synchronous voltage u qΔ Get the q-axis voltage u of the two motors q1 and u q 2:

[0063]

[0064] In formula (9), k1 and k2 are the set output ratios of motor 1 and motor 2.

[0065] Embodiment 1:

[0066] The two motors used in this embodiment are surface-mounted permanent magnet synchronous motors, both with 5 pole pairs. The resistance of motor 1 is 1.083Ω, the inductance is 3.177mH, and the permanent magnet flux is 0.1398Wb; the resistance of motor 2 is 1.5685Ω, the inductance is 4.256mH, and the permanent magnet flux is 0.1389Wb. The difference in the parameters of the two motors is the main reason for the coupling of total torque following control and torque synchronization control. In this embodiment, a two-input single-output gearbox is used to connect the common drive load, such as Figure 4 shown.

[0067] In step 2, given the reference signal T Δref Set to 0;

[0068] In step 3, the linear extended state observer bandwidth ω0 of the torque following controller and the torque synchronization controller is set to 700 rad / s, and the linear state error feedback control law gain K of the torque following controller is set to p1 The linear state error feedback control law gain K of the torque synchronization controller p2 Both are 200. At this time, the transfer functions shown in equations (7) and (8) are the same, and their Bode diagrams are as follows: Figure 5 As shown. The gain of the disturbance signal w for the total output torque T and the gain of the disturbance signal v for the torque synchronization error T Δ The maximum gain in the whole frequency band is -52.5dB, i.e. 0.0024. It can be seen that under the above parameter conditions, the proposed torque distribution control method has an obvious effect on the suppression of disturbances and realizes the decoupling of torque following control and torque synchronization control.

[0069] Depend on Figure 6 , 7 It can be seen that when the motor output ratio is set to 1:1, using the method proposed in the present invention, when the load changes, the two motors always maintain a torque distribution ratio of 1:1, while under the existing master-slave control method, the output ratio changes.

[0070] Depend on Figure 8 , 9 It can be seen that when the motor output ratio is set to 1:4, using the method proposed in the present invention, when the load changes, the two motors also maintain the torque distribution ratio of 1:4 unchanged, and the torque synchronization effect is much stronger than the existing master-slave control method.

[0071] Depend on Fig.10 and Fig.11 It can be seen that when the motor output ratio is adjusted, the total torque output has only a slight fluctuation, and the torque variation amplitude is reduced by 90% compared with the master-slave control method. The present invention can realize the decoupling control of the total torque and the torque synchronization error, and provide an excellent torque distribution control effect.

[0072] Any matters not described in the present invention are applicable to the prior art.

Claims

1. A dual-motor system torque distribution control method based on linear auto-disturbance rejection decoupling control, characterized in that: The method comprises the following steps: Step 1: Analyze the two motors as a whole and establish a torque synchronization error based on the total torque T and torque synchronization error T. Δ , q-axis following voltage u q and q-axis synchronous voltage u qΔ The decoupling model is shown in formula (1): In formula (1), b0 is the compensation factor; w and v are disturbances; Step 2: According to the decoupling model, a torque following controller based on first-order linear anti-disturbance control is designed, eliminating the tracking differentiator link, and the given reference signal is the total torque reference value T output by the speed controller. ref , the output is the q-axis following voltage u q The observed quantities of the linear extended state observer of the torque following controller are the total torque T and the disturbance w in equation (1), and its input is the q-axis following voltage u q and total torque T; According to the decoupling model, a torque synchronization controller based on first-order linear active disturbance rejection control is designed, eliminating the tracking differentiator link, and the given reference signal is the torque synchronization error reference value T Δref , the output is the q-axis synchronous voltage u qΔ , the feedback quantity is the torque synchronization error T Δ The observed value of the torque synchronization error T Δ Decomposed into the electromagnetic torque T of motor 1 e1 and the electromagnetic torque T of motor 2 e2 , decompose the disturbance v in equation (1) into two parts v1 and v2 belonging to motor 1 and motor 2, and use the bilinear extended state observer to obtain the torque synchronization error T Δ The observation value of and the observation value of disturbance v; the input of the bilinear extended state observer is the electromagnetic torque T of motor 1 e1 and the electromagnetic torque T of motor 2 e2 And the q-axis voltage u of motor 1 q1 and the q-axis voltage u of motor 2 q 2; Step 3: Determine the linear extended state observer bandwidth ω0 of the torque following controller and the torque synchronization controller and the linear state error feedback control law gain K of the torque following controller through the Bode diagram of the disturbance transfer function. p1 The linear state error feedback control law gain K of the torque synchronization controller p2 ; Step 4: The q-axis following voltage u output by the torque following controller and the torque synchronization controller q and q-axis synchronous voltage u qΔ Get the q-axis voltage u of the two motors q1 and u q2 ; and then with their respective d-axis voltage u d The two motors are input into the modulation module of the motor control system to realize dual-motor torque distribution control.

2. The dual-motor system torque distribution control method based on linear auto-disturbance rejection decoupling control according to claim 1 is characterized in that: In step 1, the disturbance w, disturbance v and compensation factor b0 satisfy: In formula (2), b i =1.5pΨ fi / L i , i = 1 or 2, and the compensation factor b0 is calculated; a i =-1.5pΨ fi (R i i qi +ωL i i di +ωΨ fi ) / L i ; R i , L i and fi is the stator resistance, stator inductance and permanent magnet flux of motor i, p is the number of motor pole pairs; i qi is the q-axis current of motor i; ω is the speed of the two motors; i di is the d-axis current of motor i; Δb1 is the difference between b1 and compensation factor b0; Δb2 is the difference between b2 and compensation factor b0; u q1 、u q2 is the q-axis voltage of motor 1 and motor 2; k1 and k2 are the set output ratios of motor 1 and motor 2.

3. The dual-motor system torque distribution control method based on linear auto-disturbance rejection decoupling control according to claim 1 is characterized in that: In step 1, the total torque T and the torque synchronization error T Δ , q-axis following voltage u q and q-axis synchronous voltage u qΔ satisfy: In formula (3), T e1 , T e2 is the electromagnetic torque of motor 1 and motor 2; k1 and k2 are the output ratios of motor 1 and motor 2; u q1 、u q2 is the q-axis voltage of motor 1 and motor 2.

4. The dual-motor system torque distribution control method based on linear auto-disturbance rejection decoupling control according to claim 1 is characterized in that: In step 2, the algorithm equation of the torque following controller is: In formula (4), · represents the derivative; ^ represents the observed value; A1 and A2 are the linear extended state observer output error correction gains of the torque following controller; K p1 is the linear state error feedback control law gain of the torque following controller; u0 is the output of the linear state error feedback control law of the torque following controller.

5. The dual-motor system torque distribution control method based on linear auto-disturbance rejection decoupling control according to claim 1 is characterized in that: In step 2, the torque synchronization error T Δ and the disturbance v are each decomposed into two parts: In formula (5), v1 and v2 are the parts of the disturbance v decomposed into motor 1 and motor 2 respectively.

6. The dual-motor system torque distribution control method based on linear auto-disturbance rejection decoupling control according to claim 1 is characterized in that: In step 2, the algorithm equation of the torque synchronization controller using the bilinear extended state observer is: In formula (6), · represents the derivative; ^ represents the observed value; A1 and A2 are the two linear extended state observer output error correction gains of the torque synchronization controller, which are the same as the linear extended state observer output error correction gain of the torque following controller; k1 and k2 are the output ratios set for motor 1 and motor 2; K p2 is the linear state error feedback control law gain of the torque synchronization controller; u0 is the output of the linear state error feedback control law of the torque synchronization controller, which is the same as the output of the linear state error feedback control law of the torque following controller.

7. The dual-motor system torque distribution control method based on linear auto-disturbance rejection decoupling control according to claim 1 is characterized in that: In step 3, the disturbance transfer function of the torque following controller, that is, the transfer function between the total torque T and the disturbance w, is: In formula (7), s represents a complex number; A1 and A2 are the linear extended state observer output error correction gains of the torque following controller; K p1 is the linear state error feedback control law gain of the torque following controller.

8. The dual-motor system torque distribution control method based on linear auto-disturbance rejection decoupling control according to claim 1, characterized in that: In step 3, the disturbance transfer function of the torque synchronization controller, that is, the torque synchronization error T Δ The transfer function between and the disturbance v is: In formula (8), s represents a complex number; A1 and A2 are the output error correction gains of the two linear extended state observers of the torque synchronization controller; K p2 is the linear state error feedback control law gain of the torque synchronization controller.

9. The dual-motor system torque distribution control method based on linear auto-disturbance rejection decoupling control according to claim 1, characterized in that: In step 4, the q-axis follows the voltage u q and q-axis synchronous voltage u qΔ Get the q-axis voltage u of the two motors q1 and u q 2: In formula (9), k1 and k2 are the set output ratios of motor 1 and motor 2.

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