A double three-phase asynchronous motor decoupling robust control method based on fundamental wave phase-locked loop

Abstract

This invention relates to a robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop (PLL), belonging to the fields of multiphase motor control and power electronics. First, this invention employs a dual second-order generalized integrator combined with a synchronous rotating coordinate system PLL to construct a fundamental PLL, extracting the fundamental angle and achieving precise flux linkage orientation. Second, a robust extended-state flux linkage observer is designed to estimate and compensate for parameter perturbations and external disturbances as extended states in real time, reducing the system's sensitivity to motor parameters. Then, a feedforward compensated current fully decoupled controller is constructed, introducing sliding mode robust terms and feedforward decoupling terms on the basis of proportional-integral control to achieve independent adjustment of the d-q axis current in the fundamental subspace. Finally, a harmonic suppression controller is established to perform closed-loop suppression of the harmonic subspace. This invention effectively improves the robustness, speed, and stability of the dual three-phase asynchronous motor control system under harsh operating conditions, and improves current harmonics and winding balance.

Description

Technical Field

[0001] This invention belongs to the field of multiphase motor technology, and in particular to a decoupling robust control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop. Background Technology

[0002] The dual three-phase asynchronous motor consists of two sets of three-phase stator windings with a spatial offset of 30° electrical angle. Compared with the traditional three-phase motor, the dual three-phase motor has higher torque density, stronger fault tolerance, low voltage high power output, low harmonic content, and small torque ripple. It can effectively solve the problems of insufficient capacity and low reliability of single inverters in high-power transmission systems and is widely used in medium and high voltage, high power, and high reliability transmission fields.

[0003] Existing dual-three-phase asynchronous motor control schemes commonly employ three-phase motor control strategies, which combine vector space decoupling transformation to separate the fundamental and harmonic subspaces for independent control. However, the following problems exist in practical applications: 1. Insufficient flux linkage orientation accuracy: Traditional phase-locked loops introduce 5th and 7th harmonics, resulting in large flux linkage orientation deviations. 2. After the motor is running, the temperature has a significant impact on the motor winding parameters, resulting in distortion of the motor model observation and poor system robustness; 3. The fundamental subspace dq-axis current cross-coupling is severe, and conventional controllers cannot achieve complete decoupling, resulting in lag in dynamic response and large torque ripple; 4. In the harmonic subspace, large harmonic currents can cause motor vibration, requiring closed-loop suppression. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a robust decoupling control method for dual three-phase asynchronous motors based on a fundamental phase-locked loop. First, an improved fundamental phase-locked loop is used to shield harmonic interference and extract the fundamental angle to achieve precise flux linkage orientation. Second, a parameter-adaptive robust expanded flux linkage state observer is designed to reduce the sensitivity of model parameters. Then, a feedforward compensated current fully decoupled controller is constructed to complete the decoupling. Finally, a harmonic suppression controller is established to perform closed-loop suppression of the harmonic subspace, thereby achieving robustness, speed, and stability of the control system.

[0005] The technical problem solved by this invention is achieved through the following technical solution: A robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop includes the following steps: Step 1: Collect the six-phase stator current, phase voltage, and DC bus voltage signals of the dual three-phase asynchronous motor; Step 2: The collected six-phase current is decomposed into fundamental wavelet space components and harmonic wavelet space components in the stationary coordinate system through vector space decoupling transformation. Step 3: Input the fundamental wave subspace component into the fundamental wave phase-locked loop module. The fundamental wave phase-locked loop module uses a combination of dual second-order generalized integrator pre-filter and synchronous rotating coordinate system phase-locked loop to extract the fundamental wave component and output accurate flux linkage orientation angle and synchronous angular velocity. Step 4: Based on the magnetic flux orientation angle, the fundamental subspace component is converted into the dq axis current component in the rotating coordinate system through the Park transformation, and the harmonic subspace component is taken as the z1-z2 axis harmonic current component. Step 5: Observe the rotor flux in real time through the robust extended state flux observer. The robust extended state flux observer expands and compensates for parameter perturbations and external disturbances as lumped disturbances, and outputs the observed rotor flux. Step 6: Based on the outer speed loop setting and the observed rotor flux linkage, generate the torque current setting and the excitation current setting; Step 7: Construct a current decoupling robust controller. Based on the dq-axis current component, torque current setpoint, excitation current setpoint, and observed rotor flux linkage, generate the fundamental subspace dq-axis voltage setpoint through feedforward compensation and robust feedback control. Simultaneously, construct a harmonic suppression controller to generate harmonic compensation voltage based on the z1-z2 axis harmonic current components. Step 8: After superimposing the dq axis voltage setpoint with the harmonic compensation voltage, the six-phase voltage setpoint is generated by sequentially performing inverse Park transformation and vector space decoupling inverse transformation. The pulse width modulation signal is then output through space vector pulse width modulation to control the inverter to drive the motor.

[0006] Furthermore, the specific implementation method of step 2 is as follows: the transformation of multiphase current into fundamental and harmonic subspaces is as follows: in, and for Axial base wave plane stator current component, and for Shaft harmonic plane stator current components, , , , , , This refers to the stator current of a dual three-phase motor.

[0007] Furthermore, the specific implementation method of step 3 is as follows: the fundamental phase-locked loop adopts a combination of dual second-order generalized integrator pre-filter and synchronous rotating coordinate system phase-locked loop, wherein DSOGI filters the fundamental voltage and current in the α-β subspace to generate orthogonal signals. , Suppressing the 5th and 7th harmonics and extracting the fundamental frequency, the transfer function is: Where k is the damping coefficient, ω0 is the fundamental angular frequency, and s is the Laplace operator. The PLL phase tracking takes the quadrature signal output by DSOGI as input and eliminates phase error through a PI controller. ; in, This is a phase error signal. This is the estimated real-time angular frequency. This is the phase estimate. The proportional gain of the PI controller. This is the integral gain of the PI controller.

[0008] Furthermore, the specific implementation method of step 4 is as follows: The Park transformation from a stationary coordinate system to a rotating coordinate system is: in, For the stator current component along the d-axis of the rotating coordinate system. For the q-axis stator current component in the rotating coordinate system. This is the orientation angle output by the phase-locked loop.

[0009] Furthermore, the specific implementation method of step 5 is as follows: in, and This refers to the stator voltage components along the dq axis in a synchronous rotating coordinate system. For stator resistance, The leakage coefficient is... For mutual inductance between stator and rotor, For the stator winding self-inductance For the rotor winding self-inductance, To synchronize the rotational angular frequency, The rotor flux component of the synchronous rotating coordinate system d-axis.

[0010] The rotor flux linkage equation is given as follows: in, For rotor resistance, This is the slip frequency.

[0011] Subsequently, a lumped perturbation extension equation was established to describe the actual system model. f d1 The lumped perturbation term includes parameter perturbations, unmodeled dynamics, and the effects of external perturbations on the flux linkage equations; h1 represents the perturbation.f d1 The rate of change, assuming h1 is unknown but bounded: in, stationary coordinate system Rotor flux linkage component.

[0012] Then, a second-order extended state observer is established to extend the disturbance into a new state. The flux linkage error is used to simultaneously correct the estimates of flux linkage and disturbance. The observer can accurately estimate the rotor flux linkage and compensate for the disturbance even under parameter perturbations and model inaccuracies. in, , The observer gain, whose magnitude directly determines the observer's convergence speed and disturbance rejection capability, is used to simplify calculations by placing the observer poles at locations faster than the motor's electrical time response. , , The frequency of the observer poles is represented by the superscript ^, which indicates the observed value.

[0013] Furthermore, the specific working method of the current decoupling robust controller in step 7 is as follows: A decoupling strategy for current feedforward compensation and robust feedback is established, containing [the following information] in the d-axis. The resulting back-potential coupling term contains in the q-axis and The resulting coupling, the cross-coupling term is: in, To decouple and compensate for the back electromotive force component along the d-axis. To decouple and compensate the back electromotive force component for the q-axis.

[0014] The decoupling controller can be designed as follows: in, , The stator voltages are given for the dq axes respectively. , The stator currents are given for the dq axes, respectively. This refers to the proportional coefficient of the current PI controller. The integral coefficient of the current pi controller is... This represents the gain of the sliding mode circuit.

[0015] The control law consists of three parts: first, a pi controller to handle the steady-state error of current tracking; second, a robust controller based on a sliding mode controller, with a sign function. This is a form of variable structure control used to compensate for model parameter perturbations, making the system robust to changes in motor parameters. The third part is feedforward compensation, which directly cancels out the coupling terms as feedforward quantities, allowing the dq-axis currents to be controlled independently. For the q-axis, unlike traditional vector control, it compensates for the rotational electromotive force generated by the rotor flux linkage, ensuring performance in the weak field region. Moreover, the specific working method for constructing the harmonic suppression controller in step 7 is as follows: in, This is the z-axis harmonic subspace stator voltage control quantity. The z-axis harmonic subspace stator current. For the proportional gain of the harmonic suppression controller, For the resonant gain of the harmonic suppression controller, The target harmonic angular frequency.

[0016] The advantages and positive effects of this invention are: This invention proposes a fundamental phase-locked loop (PLL) capable of shielding harmonic interference. Even after applying 5% of the 5th and 7th harmonic currents externally, it can still accurately capture the fundamental component for high-precision FOC control. Simultaneously, this invention proposes a robust extended state flux observer. This robust state observer, designed to accurately estimate rotor flux after applying a 5% disturbance signal to the motor model parameters, possesses parameter robustness and disturbance rejection capability. Then, this invention proposes a fully decoupled current control law. Through this scheme, the current balance of the dual windings is improved, and the amplitude difference between windings is reduced from 20% to less than 5%, improving system reliability. Finally, this invention proposes a multiphase motor harmonic suppressor. After introducing the harmonic suppressor, the current harmonics are reduced from 1.5% to below 1%, significantly reducing harmonics. In summary, this invention, through the combination of a fundamental phase-locked loop, a robust extended flux state observer, a fully decoupled current controller, and a harmonic controller, achieves robustness, speed, and stability of the control system, thereby improving the overall performance of the dual three-phase motor system. Attached Figure Description

[0017] Figure 1 This is a block diagram of the dual three-phase motor control system of the present invention; Figure 2 The diagram shows the output angular frequency and phase of the fundamental phase-locked loop of this invention. Figure 3 The magnetic flux observation diagram after applying a perturbation to this invention; Figure 4 A comparison diagram of current before and after applying control in this invention; Figure 5 A comparison diagram of current harmonics before and after applying control in this invention. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings.

[0019] A robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop includes the following steps: Step 1: Collect the six-phase stator current, phase voltage, and DC bus voltage signals of the dual three-phase asynchronous motor.

[0020] Step 2: The collected six-phase current is decomposed into fundamental wavelet space components and harmonic wavelet space components in the stationary coordinate system through vector space decoupling transformation.

[0021] The transformation of multiphase current into fundamental and harmonic subspaces is as follows: in, and for Axial base wave plane stator current component, and for Shaft harmonic plane stator current components, , , , , , This refers to the stator current of a dual three-phase motor.

[0022] Step 3: Input the fundamental wave subspace component into the fundamental wave phase-locked loop module. The fundamental wave phase-locked loop module uses a combination of dual second-order generalized integrator pre-filter and synchronous rotating coordinate system phase-locked loop to extract the fundamental wave component and output accurate flux linkage orientation angle and synchronous angular velocity.

[0023] The fundamental phase-locked loop (PLL) employs a combination of dual second-order generalized integrator pre-filters and a synchronous rotating coordinate system (DSOGI) PLL. The DSOGI filters the fundamental voltage and current in the α-β subspace to generate orthogonal signals. , Suppressing the 5th and 7th harmonics and extracting the fundamental frequency, the transfer function is: Where k is the damping coefficient, ω0 is the fundamental angular frequency, and s is the Laplace operator. The PLL phase tracking takes the quadrature signal output by DSOGI as input and eliminates phase error through a PI controller. ; in, This is a phase error signal. This is the estimated real-time angular frequency. This is the phase estimate. The proportional gain of the PI controller. This is the integral gain of the PI controller.

[0024] Step 4: Based on the magnetic flux orientation angle, the fundamental subspace component is converted into the dq-axis current component in the rotating coordinate system through the Park transformation, and the harmonic subspace component is taken as the z1-z2 axis harmonic current component.

[0025] The Park transformation from a stationary coordinate system to a rotating coordinate system is: in, For the stator current component along the d-axis of the rotating coordinate system. For the q-axis stator current component in the rotating coordinate system. This is the orientation angle output by the phase-locked loop.

[0026] Step 5: Observe the rotor flux in real time using the robust extended state flux observer. The robust extended state flux observer expands and compensates for parameter perturbations and external disturbances as lumped disturbances, and outputs the observed rotor flux.

[0027] in, and This refers to the stator voltage components along the dq axis in a synchronous rotating coordinate system. For stator resistance, The leakage coefficient is... For mutual inductance between stator and rotor, For the stator winding self-inductance For the rotor winding self-inductance, To synchronize the rotational angular frequency, The rotor flux linkage component of the synchronous rotating coordinate system d-axis; The rotor flux linkage equation is: in, For rotor resistance, This is the slip frequency; A lumped perturbation extension equation is established to describe the actual system model. This is a lumped perturbation term, including parameter perturbations, unmodeled dynamics, and the effects of external perturbations on the flux linkage equations. For disturbance The rate of change, assuming Unknown but bounded: in, stationary coordinate system Rotor flux linkage components; a second-order extended state observer is established to extend the disturbance into a new state. The flux linkage error is used to simultaneously correct the estimates of flux linkage and disturbance. The observer can accurately estimate the rotor flux linkage and compensate for the disturbance even under parameter perturbations and model inaccuracies. in, , The observer gain, whose magnitude directly determines the observer's convergence speed and disturbance rejection capability, is used to simplify calculations by placing the observer poles at locations faster than the motor's electrical time response. , , The frequency of the observer poles is represented by the superscript ^, which indicates the observed value.

[0028] Step 6: Based on the outer speed ring given and the observed rotor flux linkage, generate the torque current given and the excitation current given.

[0029] Step 7: Construct a current decoupling robust controller. Based on the dq-axis current component, torque current setpoint, excitation current setpoint, and observed rotor flux linkage, generate the fundamental subspace dq-axis voltage setpoint through feedforward compensation and robust feedback control. At the same time, construct a harmonic suppression controller to generate harmonic compensation voltage based on the z1-z2 axis harmonic current components.

[0030] The specific working method of the current decoupling robust controller is as follows: Establish a decoupling strategy between current feedforward compensation and robust feedback, containing [the following information] in the d-axis. The resulting back-potential coupling term contains in the q-axis and The resulting coupling, the cross-coupling term is: in, To decouple and compensate for the back electromotive force component along the d-axis. To decouple and compensate for the back EMF component along the q-axis, the decoupling controller is as follows: in, , The stator voltages are given for the dq axes respectively. , The stator currents are given for the dq axes, respectively. This refers to the proportional coefficient of the current PI controller. The integral coefficient of the current pi controller is... For sliding mode gain; The control law consists of three parts: first, a pi controller to handle the steady-state error of current tracking; second, a robust controller based on a sliding mode controller, with a sign function. It is a form of variable structure control used to compensate for model parameter perturbations, making the system robust to changes in motor parameters; the third part is feedforward compensation, which directly cancels the coupling terms as feedforward quantities, so that the dq axis current can be controlled independently. For the q axis, unlike traditional vector control, it compensates for the rotational electromotive force generated by the rotor flux linkage, ensuring the performance of the weak magnetic region.

[0031] The specific working method for constructing a harmonic suppression controller is as follows: in, This is the z-axis harmonic subspace stator voltage control quantity. The z-axis harmonic subspace stator current. For the proportional gain of the harmonic suppression controller, For the resonant gain of the harmonic suppression controller, The target harmonic angular frequency.

[0032] Step 8: After superimposing the dq axis voltage setpoint with the harmonic compensation voltage, the six-phase voltage setpoint is generated by sequentially performing inverse Park transformation and vector space decoupling inverse transformation. The pulse width modulation signal is then output through space vector pulse width modulation to control the inverter to drive the motor.

[0033] The above-mentioned robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop was tested to verify the effectiveness of the invention.

[0034] In this embodiment, a 7.5kW dual three-phase asynchronous motor is used. The motor windings are 30° out of phase, with a rated voltage of 380V, a rated frequency of 50Hz, 3 pole pairs, a stator resistance of 0.22Ω, a rotor resistance of 0.47Ω, a stator inductance of 0.0395H, a rotor inductance of 0.0395H, and a winding mutual inductance of 0.0364H. In the control system, the phase-locked loop (PLL) proportional gain is 18, and the integral gain is 100; the current loop proportional gain is 0.1 with an integral time of 20ms; the speed loop proportional gain is 15 with an integral time of 100ms; and the robust extended flux state observer gain is... It is 0.599. The gain is 0.1013, which needs to be considered when designing the sliding surface gain. Essentially a discontinuous control, it forces the current error to converge within a finite time. Therefore, the total uncertainty of the system must be bounded, and the gain value... It should be greater than the upper bound of the uncertain term, and after debugging... It is 0.161.

[0035] like Figure 1 As shown, the implementation process of this embodiment is as follows: Step 1: Collect six-phase stator current, phase voltage, and DC bus voltage signals, sample every 0.5ms, and average the value over the switching frequency period.

[0036] Step 2: Decouple the current into fundamental and harmonic subspace components via VSD transformation, and separate the fundamental and harmonic signals. That is, convert the six-phase currents ABC and XYZ into α-β and z1-z2 components in the stationary coordinate system.

[0037] Step 3: Input the voltage in the α-β coordinate system into the DSOGI-PLL to output the precise flux linkage orientation angle and synchronous angular velocity.

[0038] Step 4: The α-β components are fed into the sliding mode controller via dq transformation.

[0039] Step 5: The robust expanded flux linkage state observer monitors the rotor flux linkage in real time to compensate for parameter disturbances and external interference.

[0040] Step 6: The outer loop of the speed is given the output torque current, and the outer loop of the flux linkage is given the output excitation current.

[0041] Step 7: The fundamental subspace current decoupling controller independently adjusts the dq axis current and outputs the dq axis voltage. The harmonic subspace z1-z2 components are output as harmonic compensation voltages by the PR controller.

[0042] Step 8: After the two voltage inputs are superimposed, they are inversely transformed and modulated by SVPWM to output a PWM drive signal to control the inverter and drive the motor.

[0043] Step 9: Closed-loop iteration, repeat steps 1-8, control period 500μs.

[0044] Implemented in the above manner, the control effect is as follows: Figures 2 to 5 As shown.

[0045] First, such as Figure 2 As shown, after the sampled signal passes through the DSOGI fundamental phase-locked loop, it will output the pure fundamental component with harmonic components filtered out, lock the current phase and angle, and output it to the rotation transformation and robust extended state flux observer. Figure 2 The results show that the current output fundamental component is 5Hz, and the angle changes with it, eventually outputting a 5Hz fundamental component after harmonic filtering.

[0046] Then, after rotational transformation, the current is transformed into controllable dq fundamental plane current and z1-z2 harmonic plane current. The current magnetic flux is obtained through a motor model and a flux linkage observer. When motor parameters change, the observer can detect the actual magnetic flux, avoiding control accuracy deviations caused by inaccurate flux linkage orientation. Figure 3As shown, when the motor parameters are modified, the traditional voltage model fails to detect parameter changes in real time, resulting in a deviation between the observed magnetic flux and the actual magnetic flux.

[0047] Simultaneously, the current setpoint is obtained through the outer flux loop and the outer velocity loop, and then input to the fully decoupled current control law, such as... Figure 4 As shown, this scheme improves the current balance of the dual windings, reduces the amplitude difference between windings from 20% to less than 5%, and enhances the reliability of the system.

[0048] On the other hand, the harmonic subspace current obtained after rotational transformation is input to the multiphase motor harmonic suppressor for control. After introducing the harmonic suppressor, the 5th current harmonic is reduced from 0.28% to below 0.1%, and the total harmonic content is reduced from 1.4% to 0.95%. Figure 5 As shown.

[0049] Finally, the voltages after passing through each current controller are converted by rotational inverse transformation to synthesize the final 6-phase setpoint voltage, which is then modulated by SVPWM to drive the motor.

[0050] In summary, this invention achieves robustness, speed, and stability of the control system by combining a fundamental phase-locked loop, a robust extended flux state observer, a fully decoupled current controller, and a harmonic controller. At the same time, the harmonic content is reduced, thereby improving the overall performance of the dual three-phase motor system.

[0051] It should be emphasized that the embodiments described in this invention are illustrative rather than limiting. Therefore, this invention includes, but is not limited to, the embodiments described in the specific implementation. Any other implementations derived by those skilled in the art based on the technical solutions of this invention are also within the scope of protection of this invention.

Claims

1. A robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop, characterized in that: Includes the following steps: Step 1: Collect the six-phase stator current, phase voltage, and DC bus voltage signals of the dual three-phase asynchronous motor; Step 2: The collected six-phase current is decomposed into fundamental wavelet space components and harmonic wavelet space components in the stationary coordinate system through vector space decoupling transformation. Step 3: Input the fundamental wave subspace component into the fundamental wave phase-locked loop module. The fundamental wave phase-locked loop module uses a combination of dual second-order generalized integrator pre-filter and synchronous rotating coordinate system phase-locked loop to extract the fundamental wave component and output accurate flux linkage orientation angle and synchronous angular velocity. Step 4: Based on the magnetic flux orientation angle, the fundamental subspace component is converted into the dq axis current component in the rotating coordinate system through the Park transformation, and the harmonic subspace component is taken as the z1-z2 axis harmonic current component. Step 5: Observe the rotor flux in real time through the robust extended state flux observer. The robust extended state flux observer expands and compensates for parameter perturbations and external disturbances as lumped disturbances, and outputs the observed rotor flux. Step 6: Based on the outer speed loop setting and the observed rotor flux linkage, generate the torque current setting and the excitation current setting; Step 7: Construct a current decoupling robust controller. Based on the dq-axis current component, torque current setpoint, excitation current setpoint, and observed rotor flux linkage, generate the fundamental subspace dq-axis voltage setpoint through feedforward compensation and robust feedback control. Simultaneously, construct a harmonic suppression controller to generate harmonic compensation voltage based on the z1-z2 axis harmonic current components. Step 8: After superimposing the dq axis voltage setpoint with the harmonic compensation voltage, the six-phase voltage setpoint is generated by sequentially performing inverse Park transformation and vector space decoupling inverse transformation. The pulse width modulation signal is then output through space vector pulse width modulation to control the inverter to drive the motor.

2. The robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop according to claim 1, characterized in that: The specific implementation method of step 2 is as follows: the transformation of multiphase current into fundamental and harmonic subspaces is as follows: ； in, and for Axial base wave plane stator current component, and for Shaft harmonic plane stator current components, , , , , , This refers to the stator current of a dual three-phase motor.

3. The robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop according to claim 2, characterized in that: The specific implementation method of step 3 is as follows: the fundamental phase-locked loop adopts a combination of dual second-order generalized integrator pre-filter and synchronous rotating coordinate system phase-locked loop, wherein DSOGI filters the fundamental voltage and current in the α-β subspace to generate orthogonal signals. , Suppressing the 5th and 7th harmonics and extracting the fundamental frequency, the transfer function is: ； Where k is the damping coefficient, ω0 is the fundamental angular frequency, and s is the Laplace operator. The PLL phase tracking takes the quadrature signal output by DSOGI as input and eliminates phase error through a PI controller. ； in, This is the phase error signal. This is the estimated real-time angular frequency. This is the phase estimate. The proportional gain of the PI controller. This is the integral gain of the PI controller.

4. The robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop according to claim 3, characterized in that: The specific implementation method of step 4 is as follows: the Park transformation from the stationary coordinate system to the rotating coordinate system is: ； in, For the stator current component along the d-axis of the rotating coordinate system. For the q-axis stator current component in the rotating coordinate system. This is the orientation angle output by the phase-locked loop.

5. The robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop according to claim 4, characterized in that: The specific implementation method of step 5 is as follows: ； ； in, and This refers to the stator voltage components along the dq axis in a synchronous rotating coordinate system. For stator resistance, The leakage coefficient is... For mutual inductance between stator and rotor, For the stator winding self-inductance For the rotor winding self-inductance, To synchronize the rotational angular frequency, The rotor flux linkage component of the synchronous rotating coordinate system d-axis; The rotor flux linkage equation is: ； in, For rotor resistance, This is the slip frequency; A lumped perturbation extension equation is established to describe the actual system model. This is a lumped perturbation term, including parameter perturbations, unmodeled dynamics, and the effects of external perturbations on the flux linkage equations. For disturbance The rate of change, assuming Unknown but bounded: ； in, stationary coordinate system Rotor flux linkage components; a second-order extended state observer is established to extend the disturbance into a new state. The flux linkage error is used to simultaneously correct the estimates of flux linkage and disturbance. The observer can accurately estimate the rotor flux linkage and compensate for the disturbance even under parameter perturbations and model inaccuracies. ； in, , The observer gain, whose magnitude directly determines the observer's convergence speed and disturbance rejection capability, is used to simplify calculations by placing the observer poles at locations faster than the motor's electrical time response. , , The frequency of the observer poles is represented by the superscript ^, which indicates the observed value.

6. The robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop according to claim 5, characterized in that: The specific working method of the current decoupling robust controller in step 7 is as follows: Establish a decoupling strategy between current feedforward compensation and robust feedback, containing [the following information] in the d-axis. The resulting back-potential coupling term contains in the q-axis and The resulting coupling, the cross-coupling term is: ； in, To decouple and compensate for the back electromotive force component along the d-axis. To decouple and compensate for the back EMF component along the q-axis, the decoupling controller is as follows: ； in, , The stator voltages are given for the dq axes respectively. , The stator currents are given for the dq axes, respectively. This refers to the proportional coefficient of the current PI controller. The integral coefficient of the current pi controller is... For sliding mode gain; The control law consists of three parts: first, a pi controller to handle the steady-state error of current tracking; second, a robust controller based on a sliding mode controller, with a sign function. It is a form of variable structure control used to compensate for model parameter perturbations, making the system robust to changes in motor parameters; the third part is feedforward compensation, which directly cancels the coupling terms as feedforward quantities, so that the dq axis current can be controlled independently. For the q axis, unlike traditional vector control, it compensates for the rotational electromotive force generated by the rotor flux linkage, ensuring the performance of the weak magnetic region.

7. The robust decoupling control method for a dual three-phase asynchronous motor based on a fundamental phase-locked loop according to claim 6, characterized in that: The specific working method for constructing the harmonic suppression controller in step 7 is as follows: ； in, This is the z-axis harmonic subspace stator voltage control quantity. The z-axis harmonic subspace stator current. For the proportional gain of the harmonic suppression controller, For the resonant gain of the harmonic suppression controller, The target harmonic angular frequency.

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