Feedforward LADRC rotating speed control method for reduced-order load torque observer of permanent magnet synchronous motor

Abstract

The invention discloses a feedforward LADRC rotating speed control method for a reduced-order load torque observer of a permanent magnet synchronous motor. Comprising the steps that a voltage equation and a motion equation of the permanent magnet synchronous motor are established, the motion equation of the permanent magnet synchronous motor is equivalent to a first-order anti-disturbance normal form, a linear active-disturbance-rejection rotating speed controller is established according to the first-order anti-disturbance normal form, and a reduced-order load torque observer is established according to the motion equation of the permanent magnet synchronous motor. The reduced-order load torque observer is combined with a linear active-disturbance-rejection rotating speed controller to obtain a permanent magnet synchronous motor linear active-disturbance-rejection rotating speed control method based on feedforward of the reduced-order load torque observer, so that accurate tracking of a reference rotating speed and effective suppression of high-order nonlinear time-varying load disturbance are realized. And the anti-disturbance performance of the permanent magnet synchronous motor is greatly enhanced.

Description

Technical Field

[0001] The present invention belongs to the field of motors, and in particular relates to a permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control method. Background Art

[0002] At present, the electric drive industry has become the main battlefield of the energy revolution. Permanent magnet synchronous motors with high power density, high torque density and high reliability have ushered in new development opportunities in precision machining, deep-sea exploration, aerospace and other fields. However, due to reasons such as machining accuracy, assembly error and body structure, permanent magnet synchronous motors inevitably have disturbances such as cogging torque, magnetic circuit saturation, back electromotive force harmonics, and motor parameter offset, which have an adverse effect on control accuracy. In addition to the disturbances caused by the motor's own structure or parameter perturbations, permanent magnet synchronous motors are also faced with external disturbances such as friction torque and load disturbances. Due to the wide range of applications of permanent magnet synchronous motors, load disturbances are the most challenging disturbances faced by permanent magnet synchronous motors. In recent years, linear active disturbance rejection control has been successfully applied to the field of motor control due to its strong anti-disturbance performance and easy parameter setting. However, traditional linear active disturbance rejection speed control can only effectively suppress constant disturbances and slowly changing disturbances, and the suppression effect on nonlinear time-varying disturbances is not ideal. However, the application range of permanent magnet synchronous motors is very wide. In application scenarios such as electric vehicles climbing hills and flexible robotic arms, the load disturbance of permanent magnet synchronous motors is a high-order nonlinear disturbance that changes with time. Traditional linear self-disturbance rejection speed control is difficult to meet the anti-disturbance requirements in such scenarios. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a permanent magnet synchronous motor linear auto-disturbance rejection speed control method based on reduced-order load torque observer feedforward, so as to solve the problem that the traditional linear auto-disturbance rejection speed control has unsatisfactory effect in suppressing high-order nonlinear time-varying load disturbances.

[0004] Technical solution: The control method of the present invention comprises the following steps:

[0005] By establishing the voltage equation and motion equation of the permanent magnet synchronous motor, determining the controlled objects of the current loop and the speed loop, converting the motion equation of the permanent magnet synchronous motor into the first-order anti-disturbance paradigm, establishing a linear self-disturbance rejection speed controller including a linear extended state observer and a linear state error feedback control law, and establishing a reduced-order load torque observer including a linear differential tracker and a reduced-order observer, the external load torque of the permanent magnet synchronous motor is observed in real time to obtain the load torque observation value;

[0006] By multiplying the observed value of the load torque by the feedforward gain, the compensation current is obtained. Then, the compensation current is added to the control variable after the limit of the linear active disturbance rejection speed controller to obtain the q-axis reference current. The q-axis reference current is given to the q-axis current PI controller and acts together with the space vector pulse width modulation (SVPWM) to drive the permanent magnet synchronous motor to rotate, so that the speed of the permanent magnet synchronous motor closely follows the reference speed, achieving precise control of the speed of the permanent magnet synchronous motor and effective suppression of the non-linear time-varying load disturbance.

[0007] Furthermore, in the linear active disturbance rejection speed controller, the linear extended state observer receives the feedback speed signal to observe the rotor mechanical angular velocity and the total disturbance; the linear state error feedback control law receives the reference speed signal and combines the speed observation value, the total disturbance observation value and the proportional controller gain to generate the first control variable u0, and the control variable u is obtained after the limit of the first control variable u0.

[0008] Furthermore, the linear extended state observer is designed as:

[0009]

[0010] where z1 is the observed value of the rotor mechanical angular velocity, z2 is the observed value of the total disturbance, b0 is the inherent parameter of the system, u is the second control variable output after the limit of the linear active disturbance rejection speed controller, ω o is the bandwidth of the linear extended state observer, y is the state variable, y = ω m ω m is the rotor mechanical angular velocity, and t represents time.

[0011] Furthermore, the linear state error feedback control law is designed as

[0012]

[0013] where u is the second control variable output after the limit of the linear active disturbance rejection speed controller, k p is the proportional controller gain, ω mref is the reference speed, z1 is the observed value of the rotor mechanical angular velocity, z2 is the observed value of the total disturbance, and b0 is the inherent parameter of the system.

[0014] Furthermore, the expression of the linear tracking differentiator is:

[0015]

[0016] where x1 is the low-pass filtered rotor mechanical angular velocity signal; x2 is the first derivative of the low-pass filtered rotor mechanical angular velocity; r is the tracking gain proportional to the tracking speed, ω m is the rotor mechanical angular velocity, and t represents time.

[0017] Furthermore, the reduced-order load torque observer is designed as follows:

[0018] Taking the load torque T L as the variable to be observed, a reduced-order load torque observer is established as follows:

[0019]

[0020] wherein, T Lc is the calculated value of the load torque T L , T Lh is the observed value of the load torque T L , J is the moment of inertia, B v is the viscous friction coefficient, x1 is the rotor mechanical angular velocity signal after low-pass filtering, x2 is the first derivative of the rotor mechanical angular velocity after low-pass filtering, P n is the number of rotor pole pairs, ψ f is the permanent magnet flux linkage, i q is the q-axis stator current, h is the observation gain proportional to the convergence speed of the reduced-order load torque observer, and t represents time.

[0021] Furthermore, the obtained q-axis reference current is as follows:

[0022] i qref =K c T Lh +u

[0023] wherein, i qref is the q-axis reference current, K c is the feedforward gain, T Lh is the observed value of the load torque T L , and u is the second control variable output after the linear active disturbance rejection speed controller is limited.

[0024] The control system of the present invention includes:

[0025] A load torque observation unit, which is used to determine the controlled objects of the current loop and the speed loop by establishing the voltage equation and the motion equation of the permanent magnet synchronous motor, transform the motion equation of the permanent magnet synchronous motor into a first-order anti-disturbance normal form, establish a linear active disturbance rejection speed controller including a linear extended state observer and a linear state error feedback control law, establish a reduced-order load torque observer including a linear differential tracker and a reduced-order observer, and perform real-time observation on the external load torque of the permanent magnet synchronous motor to obtain the observed value of the load torque;

[0026] The speed control unit is used to obtain a compensation current by multiplying the observed value of the load torque by a feedforward gain, add the compensation current to the control variable limited by the linear active disturbance rejection speed controller, obtain the q-axis reference current, supply the q-axis reference current to the q-axis current PI controller, and jointly act with the space vector pulse width modulation (SVPWM) to drive the permanent magnet synchronous motor to operate at a speed, enabling the speed of the permanent magnet synchronous motor to closely follow the reference speed, achieving precise control of the speed of the permanent magnet synchronous motor and effectively suppressing the non-linear time-varying load disturbance.

[0027] The electronic device of the present invention includes a memory, a processor, and a computer program / instructions stored on the memory and executable on the processor. When the computer program / instructions are executed by the processor, the steps of the feedforward LADRC speed control method for the permanent magnet synchronous motor with a reduced-order load torque observer are implemented.

[0028] The computer-readable storage medium of the present invention stores computer instructions. When the computer instructions are called, they are used to execute the steps of the feedforward LADRC speed control method for the permanent magnet synchronous motor with a reduced-order load torque observer.

[0029] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are as follows: (1) Making full use of the known permanent magnet synchronous motor model information, achieving precise observation of the load torque disturbance and reducing the disturbance observation burden of the linear extended state observer; (2) Reducing the speed fluctuation when the load torque disturbance suddenly changes and enhancing the disturbance suppression ability of the permanent magnet synchronous motor to the load torque disturbance; (3) The linear tracking differentiator extracts the first derivative of ω m to avoid the adverse effect of amplifying the ω m sampling noise caused by direct differential operation; (4) The reduced-order load torque observer only includes two tuning parameters, namely the observer gain h and the differential tracking gain r, and both tuning parameters are proportional to the observer convergence speed, reducing the parameter tuning difficulty. Description of the Drawings

[0030] Figure 1 is a flowchart of the control method of the present invention;

[0031] Figure 2 is an overall block diagram of the PMSM control system of the present invention;

[0032] Figure 3 is a principle block diagram of the linear active disturbance rejection speed controller in the present invention;

[0033] Figure 4 is a principle block diagram of the reduced-order load torque observer in the present invention;

[0034] Figure 5It is the observation curve of the load torque by the reduced-order load torque observer designed by the present invention;

[0035] Figure 6 It is the comparison curve of the speed fluctuations under the action of the control method of the present invention and the traditional LADRC method when a load torque disturbance of 2.0 Nm is suddenly applied. Specific embodiments

[0036] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] The present invention first establishes a reduced-order load torque observer. By establishing the voltage equation and motion equation of the permanent magnet synchronous motor, the controlled objects of the current loop and speed loop are determined, and the motion equation of the permanent magnet synchronous motor is transformed into a first-order anti-disturbance normal form; a linear active disturbance rejection speed controller including a linear extended state observer and a linear state error feedback control law is established; a reduced-order load torque observer including a linear differential tracker and a reduced-order observer is established; the load torque of the permanent magnet synchronous motor is observed in real time to obtain the observed value of the load torque. Then, speed control is performed. By multiplying the observed value of the load torque by the feedforward gain K c , the compensation current i qb is obtained, and the compensation current i qb and the controlled variable u after being limited by the linear active disturbance rejection speed controller are added together to obtain the q-axis reference current i qref . The i qref is given to the q-axis current PI controller, and together with the space vector pulse width modulation SVPWM, it drives the speed of the permanent magnet synchronous motor to work, enabling the permanent magnet synchronous motor to closely follow the reference speed and improving the suppression ability of the permanent magnet synchronous motor to non-linear time-varying load disturbances.

[0038] As Figure 1 shown, a reduced-order load torque observer feedforward linear active disturbance rejection control (LADRC) speed control method for a permanent magnet synchronous motor (PMSM) includes the following steps:

[0039] Step 1, establish the voltage equation and motion equation of the PMSM.

[0040] The voltage equation of the PMSM is:

[0041]

[0042] Among them, i d represents the d-axis stator current, i q is the q-axis stator current, u d is the d-axis stator voltage, u q is the q-axis stator voltage, R s is the stator phase resistance, L d is the d-axis stator inductance, L qis the q - axis stator inductance. For the surface - mounted permanent - magnet synchronous motor, L d = L q , ψ f is the permanent - magnet flux linkage, ω e is the rotor electrical angular velocity, and t represents time.

[0043] The motion equation of the PMSM is:

[0044]

[0045] Among them, ω m is the rotor mechanical angular velocity, J is the moment of inertia, k t is the electromagnetic torque coefficient, k t = 1.5P n ψ f , P n is the number of rotor pole pairs; B v is the viscous friction coefficient, and T L is the load torque disturbance.

[0046] In addition, the rotor electrical angular velocity ω e , the rotor mechanical angular velocity ω m , the rotor electrical angle θ e and the rotor mechanical angle θ m satisfy the following relationship:

[0047]

[0048] Step 2: Transform the motion equation of the PMSM into the first - order anti - disturbance normal form, and establish a linear active disturbance rejection (LADRC) speed controller including a linear extended state observer (LESO) and a linear state error feedback control law (LESF), as follows:

[0049] As Figure 2 shown, the PMSM control system adopts a current - speed double - closed - loop control structure, where the current loop is the inner loop and the speed loop is the outer loop. The current loop includes a current controller and the controlled object of the current loop, and the controlled object of the current loop is the voltage equation of the permanent - magnet synchronous motor. The speed loop includes a speed controller and the controlled object of the speed loop, and the controlled object of the speed loop is the motion equation of the PMSM. The control system of the permanent - magnet synchronous motor includes a permanent - magnet synchronous motor, an encoder, a load, a coupling connecting the load and the permanent - magnet synchronous motor, and a microprocessor that executes the control algorithm. Figure 2 The structure shown is the PMSM control system.

[0050] Select the state variable y = ω m , and equivalent the load torque disturbance and friction disturbance in the PMSM motion equation to the total disturbance f. Then the motion equation of the PMSM is transformed into the first - order anti - disturbance normal form as:

[0051]

[0052] Among them, b0 is an inherent parameter of the system, and b0 = k t / J.

[0053] As Figure 3 shown, the linear active disturbance rejection speed controller includes two parts: a linear extended state observer and a linear state error feedback control law. The linear extended state observer receives the rotor mechanical angular velocity ω m , and observes the total disturbance and the rotor mechanical angular velocity of the permanent magnet synchronous motor in real time; the linear state error feedback control law receives the reference speed signal, and combines the observed value z1 of the rotor mechanical angular velocity, the observed value z2 of the total disturbance, and the proportional controller gain k p to obtain the first control variable u0; the first control variable u0 passes through a limiting link to obtain the second control variable u, that is, the linear state error feedback control law.

[0054] According to the first-order anti-disturbance normal form of the permanent magnet synchronous motor motion equation, a linear extended state observer for observing speed and total disturbance is established:

[0055]

[0056] Among them, z1 is the observed value of the rotor mechanical angular velocity ω m , z2 is the observed value of the total disturbance f, and ω o is the bandwidth of the linear extended state observer.

[0057] The linear state error feedback control law is designed as

[0058]

[0059] Among them, k p is the proportional controller gain, and ω mref is the reference speed.

[0060] Step 3: Design a reduced-order load torque observer including a linear differential tracker and a reduced-order observer according to the motion equation (2) of the permanent magnet synchronous motor to observe the external load torque of the permanent magnet synchronous motor in real time and obtain the observed value of the load torque.

[0061] As Figure 4 shown, the reduced-order load torque observer includes a linear tracking differentiator and a reduced-order observer. The linear tracking differentiator is used to perform low-pass filtering on ω m and extract the first derivative of the low-pass filtered ω m , and the reduced-order observer is used to observe the load torque in real time.

[0062] Since the control period of the permanent magnet synchronous motor is much smaller than the mechanical time constant, it can be considered that the differential of the load torque T L is 0 within one control period. Selecting the rotor mechanical angular velocity ω m and the load torque T L as state variables, the motion equation (2) of the permanent magnet synchronous motor can be rewritten as:

[0063]

[0064] Since the rotor mechanical angular velocity ω m can be calculated by differentiating the rotor mechanical angle θ m fed back by the encoder, the first-order differential of ω m can be obtained through derivative operation. Therefore, T L can be directly calculated.

[0065] However, ω m contains a large amount of sampling noise. Directly calculating the differential will further amplify the noise signal in ω m , resulting in serious distortion of the directly calculated load torque. Therefore, a linear tracking differentiator is used to perform low-pass filtering on ω m and extract the first-order differential of the low-pass filtered ω m .

[0066] The expression of the linear tracking differentiator is:

[0067]

[0068] where x1 is the signal of the low-pass filtered rotor mechanical angular velocity ω m ; x2 is the first-order differential of the low-pass filtered rotor mechanical angular velocity ω m ; r is the tracking gain proportional to the tracking speed.

[0069] According to the motion model of the permanent magnet synchronous motor, a reduced-order observer is established. The q-axis current i q , x1, and x2 are input into the reduced-order observer to obtain the observed value T Lh of the load torque.

[0070] Taking T L as the variable to be observed, a reduced-order load torque observer is established:

[0071]

[0072] where T Lc is the calculated value of T L ; T Lh is the observed value of T L ; h is the observation gain proportional to the convergence speed of the reduced-order load torque observer.

[0073] Step 4: Multiply the load torque observation value by the feedforward gain K c , to obtain the compensation current i qb . Add the compensation current i qb and the second control variable u output after limiting by the linear active disturbance rejection speed controller to obtain the q-axis reference current i qref , and feed i qref to the q-axis current PI controller. The calculation formula of i qref is:

[0074]

[0075] where K c is the feedforward gain, i qb is the compensation current, and i qref1 is the second intermediate variable.

[0076] Step 5: The reduced-order load torque observer, the linear active disturbance rejection speed controller, the d-axis current PI controller, the q-axis current PI controller, and the space vector pulse width modulation SVPWM act together to drive the permanent magnet synchronous motor to move, so that the speed of the permanent magnet synchronous motor closely follows the reference speed, realizing the precise control of the speed of the permanent magnet synchronous motor and the effective suppression of the non-linear time-varying load disturbance.

[0077] The control system of the present invention includes:

[0078] A load torque observation unit, which is used to determine the controlled objects of the current loop and the speed loop by establishing the voltage equation and the motion equation of the permanent magnet synchronous motor, transform the motion equation of the permanent magnet synchronous motor into a first-order anti-disturbance normal form, establish a linear active disturbance rejection speed controller including a linear extended state observer and a linear state error feedback control law, establish a reduced-order load torque observer including a linear differential tracker and a reduced-order observer, and perform real-time observation on the external load torque of the permanent magnet synchronous motor to obtain the load torque observation value;

[0079] A speed control unit, which is used to obtain the compensation current by multiplying the load torque observation value by the feedforward gain, add the compensation current and the control variable output after limiting by the linear active disturbance rejection speed controller to obtain the q-axis reference current, feed the q-axis reference current to the q-axis current PI controller, and act together with the space vector pulse width modulation SVPWM to drive the speed of the permanent magnet synchronous motor to work, so that the speed of the permanent magnet synchronous motor closely follows the reference speed, realizing the precise control of the speed of the permanent magnet synchronous motor and the effective suppression of the non-linear time-varying load disturbance.

[0080] The electronic device described in the present invention includes a memory, a processor, and a computer program / instructions stored in the memory and executable on the processor. When the computer program / instructions are executed by the processor, the steps of the reduced-order load torque observer feedforward LADRC speed control method for the permanent magnet synchronous motor are implemented.

[0081] The computer-readable storage medium described in the present invention stores computer instructions. When the computer instructions are called, they are used to execute the steps of the reduced-order load torque observer feedforward LADRC speed control method for the permanent magnet synchronous motor.

[0082] Example verification: To verify the effectiveness and superiority of the reduced-order load torque observer feedforward LADRC speed control method for the permanent magnet synchronous motor of the present invention, the parameters of the permanent magnet synchronous motor in Table 1 below are selected, and a control system model of the permanent magnet synchronous motor based on the reduced-order load torque observer feedforward LADRC speed control method (as Figure 2 shown) and a control system model of the permanent magnet synchronous motor based on the traditional LADRC speed control method are established. The rotor mechanical angular velocity fluctuations of the reduced-order load torque observer feedforward LADRC speed control method and the traditional LADRC speed control method under load mutation conditions are compared to verify the superiority of the reduced-order load torque observer feedforward LADRC speed control method in disturbance suppression.

[0083] Table 1 Parameters of the permanent magnet synchronous motor

[0084] Physical parameter Value Physical parameter Value Phase resistance 0.055Ω d-axis inductance 0.19mH q-axis inductance 0.19mH Number of rotor pole pairs 5 Permanent magnet flux linkage 0.0125Wb DC bus voltage 48V Moment of inertia <![CDATA[1.57 kg·cm 2 > Viscous coefficient <![CDATA[8.365×10 -5 >

[0085] The reference speed of the permanent magnet synchronous motor control system is set to 1500 rpm, the sampling frequency and the inverter switching frequency are both set to 10 kHz, the initial load torque disturbance is 0.0 Nm, a load torque disturbance of 2.0 Nm is suddenly applied at 0.3 s, and the suddenly applied 2.0 Nm load torque disturbance is removed at 0.6 s. The following controller parameters are selected for comparison:

[0086] Select the parameters of the reduced-order load torque observer feedforward LADRC speed control method: tracking gain r = 500, observer gain h = 500, feedforward gain K c = 3.5; Select the parameters of the LADRC speed controller: the bandwidth ω of the linear extended state observer o = 900, the system inherent parameter b0 = 1000, proportional gain k p = 900. Select the parameters of the d-axis current PI controller: d-axis proportional coefficient k pd = 1000πL d , d-axis integral coefficient k id = 1000πR s , select the parameters of the q-axis current PI controller: q-axis proportional coefficient kpq = 1000πL d , q-axis integration coefficient k iq = 1000πR s .

[0087] Figure 5 This is the observation result of the load torque by the reduced-order load torque observer proposed in the present invention. The initial load torque is 0 N·m, and the load torque suddenly changes to 2.0 N·m at 0.3 s, and the load torque returns from 2.0 N·m to 0 N·m at 0.6 s. It can be seen from the figure that the load observer can converge quickly and closely follow the actual load torque. Even when the load torque suddenly changes, the curve of the observed value of the load torque still coincides with the curve of the actual load torque, indicating that the proposed reduced-order load torque observer can accurately observe the actual load torque.

[0088] Figure 6 This is a comparison chart of the PMSM speed curves under the control of the method proposed in the present invention and the PMSM speed curves under the control of the traditional LADRC method when a load torque of 2.0 N·m is suddenly applied. At the moment when the load torque is suddenly applied, the PMSM speed curve under the control of the traditional LADRC method drops to 1422 rpm, and the drop amplitude is 78 rpm. In contrast, the PMSM speed curve under the control of the method proposed in the present invention drops to 1463 rpm, and the drop amplitude is only 37 rpm, and the speed drop is reduced by 41 rpm. By comparing the PMSM speed curves under the control of the two methods, it can be seen that compared with the traditional LADRC method, the method proposed in the present invention has stronger disturbance rejection ability and can further reduce the speed drop of the PMSM when the load torque is suddenly applied.

Claims

1. A permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control method, characterized in that: The following steps are involved: By establishing the voltage equation and motion equation of the permanent magnet synchronous motor, determining the controlled objects of the current loop and the speed loop, converting the motion equation of the permanent magnet synchronous motor into the first-order anti-disturbance paradigm, establishing a linear self-disturbance rejection speed controller including a linear extended state observer and a linear state error feedback control law, and establishing a reduced-order load torque observer including a linear differential tracker and a reduced-order observer, the external load torque of the permanent magnet synchronous motor is observed in real time to obtain the load torque observation value; The compensation current is obtained by multiplying the load torque observation value by the feedforward gain, and the compensation current is added to the control variable after limiting by the linear anti-disturbance speed controller to obtain the q-axis reference current. The q-axis reference current is given to the q-axis current PI controller, and combined with the space vector pulse width modulation SVPWM, the permanent magnet synchronous motor is driven to work at a speed, so that the speed of the permanent magnet synchronous motor closely follows the reference speed, thereby achieving precise control of the speed of the permanent magnet synchronous motor and effective suppression of nonlinear time-varying load disturbances.

2. The permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control method according to claim 1 is characterized in that: The linear extended state observer in the linear active disturbance rejection speed controller receives the feedback speed signal and observes the rotor mechanical angular velocity and the total disturbance; The linear state error feedback control law receives a reference speed signal, and combines the speed observation value, the total disturbance observation value and the proportional controller gain to generate a first control variable u0. The first control variable u0 is limited to obtain a control variable u.

3. The permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control method according to claim 1, characterized in that: The linear extended state observer is designed as: Where z1 is the observed value of the rotor mechanical angular velocity, z2 is the observed value of the total disturbance, b0 is the inherent parameter of the system, u is the second control variable output by the linear auto-disturbance rejection speed controller after limiting, ω o is the bandwidth of the linear extended state observer, y is the state variable, y=ω m ,ω m is the rotor mechanical angular velocity, and t represents time.

4. The permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control method according to claim 1, characterized in that: The linear state error feedback control law is designed as, Where u is the second control variable output by the linear auto-disturbance rejection speed controller after limiting, k p is the proportional controller gain, ω mref is the reference speed, z1 is the observed value of the rotor mechanical angular velocity, z2 is the observed value of the total disturbance, and b0 is the system inherent parameter.

5. The permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control method according to claim 1, characterized in that: The expression of the linear tracking differentiator is: Where x1 is the rotor mechanical angular velocity signal after low-pass filtering; x2 is the first-order differential of the rotor mechanical angular velocity after low-pass filtering; r is the tracking gain proportional to the speed of the tracking differential, ω m is the rotor mechanical angular velocity, and t represents time.

6. The permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control method according to claim 1, characterized in that: The reduced-order load torque observer is designed as: With load torque T L As the variable to be observed, the reduced-order load torque observer is established as: Among them, T Lc is the load torque T L The calculated value, T Lh is the load torque T L The observed value, J is the moment of inertia, B v is the viscous friction coefficient, x1 is the rotor mechanical angular velocity signal after low-pass filtering, x2 is the first-order differential of the rotor mechanical angular velocity after low-pass filtering, P n is the number of rotor pole pairs, ψ f is the permanent magnet flux, i q is the q-axis stator current, h is the observation gain proportional to the convergence speed of the reduced-order load torque observer, and t represents time.

7. The permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control method according to claim 1, characterized in that: The obtained q-axis reference current is: i qref =K c T Lh +u Among them, i qref is the q-axis reference current, K c is the feedforward gain, T Lh is the load torque T L The observed value of u is the second controlled variable output by the linear auto-disturbance rejection speed controller after limiting.

8. A permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control system, characterized in that: include: The load torque observation unit is used to determine the controlled objects of the current loop and the speed loop by establishing the voltage equation and the motion equation of the permanent magnet synchronous motor, convert the motion equation of the permanent magnet synchronous motor into a first-order anti-disturbance paradigm, establish a linear self-disturbance rejection speed controller including a linear extended state observer and a linear state error feedback control law, establish a reduced-order load torque observer including a linear differential tracker and a reduced-order observer, observe the external load torque of the permanent magnet synchronous motor in real time, and obtain the load torque observation value; The speed control unit is used to obtain the compensation current by multiplying the load torque observation value by the feedforward gain, and add the compensation current and the control variable after the linear self-disturbance rejection speed controller is limited to obtain the q-axis reference current. The q-axis reference current is given to the q-axis current PI controller, and combined with the space vector pulse width modulation SVPWM, the permanent magnet synchronous motor speed is driven to work, so that the permanent magnet synchronous motor speed closely follows the reference speed, thereby realizing precise control of the permanent magnet synchronous motor speed and effective suppression of nonlinear time-varying load disturbances.

9. An electronic device, characterized in that: It comprises a memory, a processor and a computer program / instruction stored in the memory and executable on the processor, wherein when the computer program / instruction is executed by the processor, the steps of the permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, which, when called, are used to execute the steps of the permanent magnet synchronous motor reduced-order load torque observer feedforward LADRC speed control method as described in any one of claims 1 to 7.

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