Permanent magnet synchronous servo drive system motion control method and system based on state observation

Abstract

The invention belongs to the technical field of motor control, and particularly discloses a permanent magnet synchronous servo drive system motion control method and system based on state observation, and the method comprises the steps: building a mathematical model of a permanent magnet synchronous motor PMSM under a static coordinate system, designing an inner ring super-spiral sliding mode observer to estimate the current and the counter electromotive force on the basis of the current and the counter electromotive force under the static coordinate system; calculating the position and the speed of the rotor through the back electromotive force obtained through observation; and designing an outer ring superspiral sliding mode observer to realize load disturbance estimation and anti-disturbance control. According to the method, accurate estimation and compensation of current, rotor position, speed and load disturbance can be realized under the working conditions of disturbance and sensor failure, the reliability, robustness and dynamic performance of a servo system are effectively improved, and the method is suitable for the field of industrial automation and high-performance motion control.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of motor control, and more particularly relates to a state observation-based motion control method and system for a permanent magnet synchronous servo driving system. BACKGROUND

[0002] Permanent magnet synchronous motors are widely used in industrial automation due to their high efficiency, large power density, and rapid dynamic response. In high-performance permanent magnet synchronous motor vector control technology, accurate rotor position information is crucial for decoupling control of excitation current and torque current. The traditional solution is to use a position sensor to obtain rotor position information. However, as the application scenarios of permanent magnet synchronous motors become more diverse, the harsh production environment makes the traditional permanent magnet synchronous motor control method using a position sensor unable to meet the requirements in terms of weight and volume. Moreover, there are problems such as high sensor cost, susceptibility to interference, and high risk of failure. At the same time, as the application scenarios extend, such as in the case of robotic arms, it is inevitable to face multi-source disturbances such as contact force impact, end load changes, and motion component friction. Therefore, position sensorless control technology with strong disturbance rejection has been extensively researched and focused on in recent years.

[0003] Current permanent magnet synchronous motor position sensorless control technology can be divided into high-frequency voltage injection method, model reference adaptive method, and sliding mode observer method according to the implementation method. The high-frequency voltage injection method inevitably causes noise problems and has its own characteristics, which limit its application in situations where noise requirements are high and rotational speed is high. The model reference adaptive method has weak robustness and difficulty in parameter tuning. The sliding mode observer is insensitive to parameter perturbation, inaccurate modeling, and bounded disturbance, and can maintain observation error convergence under the condition of "matched uncertainty", and is gradually applied to the field of permanent magnet synchronous motor position sensorless control.

[0004] Existing sliding mode observers have the problems of chattering and slow convergence speed, and lack a solution that can achieve permanent magnet synchronous motor position sensorless control while ensuring the disturbance rejection of the servo driving system. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application provides a state observation-based motion control method and system for a permanent magnet synchronous servo driving system, which aims to improve the reliability, robustness, and dynamic performance of the permanent magnet synchronous servo system.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present application, a state observation-based motion control method for a permanent magnet synchronous servo driving system is proposed, comprising the following steps: In the inner-loop super-helical sliding mode observer: the observed current is obtained according to the current observation equation of the permanent magnet synchronous motor; the current observation error is obtained according to the deviation between the observed current and the measured current; based on the current observation error, the observed back electromotive force is estimated by the super-helical sliding mode control method; Based on the back electromotive force estimated by the inner ring super-helical sliding mode observer, the observed rotor position and the first observed rotational speed are obtained; In the outer ring super-helical sliding mode observer: the second observed speed is obtained according to the speed observation equation of the permanent magnet synchronous motor; the speed observation error is obtained according to the deviation between the first and second observed speeds; based on the speed observation error, the observed disturbance torque is estimated by the super-helical sliding mode control method; By cascading the observed rotor position, the first observed speed, and the observed disturbance torque into a three-level control architecture of position-speed-current, servo motion control of the permanent magnet synchronous motor is achieved.

[0007] As a further preferred embodiment, the current observation equation is as follows:

[0008]

[0009] In the formula, , They are respectively axis, The observed current of the axis, , They are respectively , The first derivative, , They are respectively axis, The back electromotive force of the axis is observed. , They are respectively axis, The given voltage of the shaft; Indicates stator resistance. This indicates the stator inductance.

[0010] As a further preferred method, based on the current observation error, a super-spiral sliding mode control method is used to estimate the observed back electromotive force, specifically:

[0011]

[0012] In the formula, , They are respectively axis, Current observation error of the shaft, , , , They are respectively axis, Measured current of the shaft; t For integration time variable, dt For the derivative with respect to time, , , , , , , These are the coefficients of the superspiral algorithm. n Pick or and satisfy , >0, , , .

[0013] As a further preferred method, the observed rotor position and the first observed rotational speed are obtained based on the observed back electromotive force estimated by the inner-ring super-helical sliding mode observer, specifically:

[0014]

[0015] In the formula, To observe the rotor position, The first observed rotational speed, For rotor flux linkage.

[0016] As a further preferred embodiment, the rotational speed observation equation is:

[0017] In the formula, For the second observed rotational speed, for The first derivative, To observe the disturbance torque; The torque coefficient, For q-axis current, The coefficient of viscous friction is... This represents the rotor's moment of inertia.

[0018] As a further preferred method, based on the rotational speed observation error, the observed disturbance torque is estimated using a super-helical sliding mode control method, specifically as follows:

[0019] In the formula, For speed observation error, ; , , , , , , For the coefficients of the superspiral algorithm, satisfying , >0, , , .

[0020] As a further preferred embodiment, the observed rotor position, the first observed speed, and the observed disturbance torque are cascaded into a three-level control architecture of position-speed-current to achieve servo motion control of the permanent magnet synchronous motor, including: The position error is obtained by subtracting the desired rotor position from the observed rotor position; the position regulator performs PI control based on the position error and outputs the desired speed. The speed error is obtained by subtracting the desired speed output from the position regulator from the first observed speed; the speed regulator performs PI control based on the speed error and outputs the desired torque. Based on the desired torque and the observed disturbance torque, the desired current is obtained; the difference between the desired current and the measured current is used to obtain the current error; the current regulator performs PI control based on the current error, outputs the desired voltage of the motor, and feeds it back to the inner loop super-spiral sliding mode observer.

[0021] As a further preferred option, the desired current is obtained based on the desired torque and the observed disturbance torque, specifically: , ,in, For the desired torque, To observe the disturbance torque, To compensate for the torque after feedforward, The torque coefficient, The desired current along the q-axis is set to 0; the desired current along the d-axis is set to 0.

[0022] As a further preferred method, the difference between the desired current and the measured current is taken to obtain the current error, specifically: Based on the observed rotor position, the three-phase currents measured by the current sensor are transformed to obtain the measured currents of the q-axis and d-axis. Then, the difference between the expected current and the measured current of the q-axis and the difference between the expected current and the measured current of the d-axis are calculated to obtain the q-axis current error and the d-axis current error.

[0023] According to another aspect of the present invention, a motion control system for a permanent magnet synchronous servo drive system based on state observation is provided, including a processor, the processor being used to execute the above-described motion control method for a permanent magnet synchronous servo drive system based on state observation.

[0024] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: 1. This invention employs a superspiral algorithm based on the sliding mode observer to achieve sensorless control, which can reduce system cost and improve reliability. Compared to first-order sliding mode, it can significantly reduce jitter while maintaining robustness to unknown disturbances. Furthermore, it adopts a cascaded structure based on the sliding mode observer, connecting observer units in series to estimate higher-order states or disturbances layer by layer. Each level of observer uses the observation error of its predecessor as input, progressively stripping away system uncertainties and effectively suppressing model uncertainties and external interference. This effectively improves the reliability, robustness, and dynamic response performance of the servo system.

[0025] 2. This invention achieves real-time disturbance rejection control for load changes through outer-loop disturbance observation and feedforward compensation; by integrating multi-loop observation and compensation mechanisms, it can accurately estimate and compensate for current, rotor position, speed and load disturbances under operating conditions with disturbances and sensor failures, meeting the requirements of high-performance motion control and suitable for complex industrial application scenarios. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the application of the cascaded superspiral sliding mode observer in an embodiment of the present invention; Figure 2 This is a schematic diagram of the control flow of the cascaded superspiral sliding mode observer according to an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0028] This invention provides a motion control method for a permanent magnet synchronous servo drive system based on state observation. It is implemented using a superspiral sliding mode observer, which is a second-order sliding mode algorithm. It utilizes a continuous control strategy that introduces an integrator to eliminate chattering caused by discontinuous switching. The basic idea is to add a term that integrates the sliding variable to the equivalent sliding mode control law to achieve continuous change of the control quantity, thereby improving convergence accuracy and avoiding high-frequency chattering.

[0029] like Figure 1 and Figure 2 As shown, the motion control of the permanent magnet synchronous servo drive system includes the following steps: Step 1: Construct a mathematical model of the permanent magnet synchronous motor (PMSM). Establish current and voltage equations in a two-phase stationary coordinate system, which will serve as the basis for the observer design.

[0030] At rest In a coordinate system, the mathematical model can be represented as:

[0031]

[0032] In the formula, and They are shaft and shaft current, and They are and The first derivative, and They are respectively shaft and shaft voltage, Indicates stator resistance. Indicates stator inductance, and They are respectively shaft and The back electromotive force of the shaft, Represents rotor flux linkage. It is the electric angular velocity (i.e., rotational speed). This is the electrical angle (i.e., rotor position).

[0033] Based on the framework of Magnetic Field Oriented Vector Control (FOC), the mechanical motion equations are:

[0034] In the formula It is the q-axis current. The torque coefficient, The moment of inertia of the rotor. The coefficient of viscous friction is... This is a lumped disturbance.

[0035] Step 2: Inner-loop state observer design. Design an inner-loop super-helical sliding mode observer to estimate the current state and back EMF state, in order to achieve sensorless current closed-loop control.

[0036] by shaft and The superhelical algorithm is constructed for each axis, using a known given voltage. , and measured current , Achieve finite-time estimation of the back electromotive force. Specifically: The equation for current observation is:

[0037]

[0038] In the formula and for shaft and The observed current of the axis, and They are respectively shaft and The back electromotive force of the axis is observed. and Taken from the stator voltage setpoint.

[0039] The back electromotive force (EMF) is estimated using the super-helical sliding mode control method. The back EMF observation equation is as follows:

[0040]

[0041] in, , for shaft and Current observation error of the shaft, , ; , , , , , , Let n be the coefficient of the constructed superspiral algorithm. , ; , , , , The selection satisfies , >0, , , .

[0042] It should be noted that the actual working mechanism is as follows: 1. Based on For example, initially, 1. Start from zero initial value; 2. Based on input voltage Known And estimating the back electromotive force Integral 3. Measured current With estimated current The difference, that is, the current observation error, is passed through the back electromotive force observation equation (super-spiral sliding mode observer) to make the system converge; 4. After approaching the true current, use it with the estimated current. The difference is used to calculate the estimated value of the back electromotive force based on the back electromotive force observation equation; 5. The back electromotive force value is used to estimate the speed and rotor position after low-pass filtering. The actual working mechanism of the subsequent step four is similar.

[0043] Step 3: Position and velocity estimation. The observed rotor position and the first observed rotational speed are derived based on the observed back electromotive force estimated by the inner loop observer.

[0044] The rotor's electric angular position and electric angular velocity are obtained from the geometric relationship of the back electromotive force, thus providing crucial information for field-oriented control (FOC) and enabling sensorless vector control. Based on the observed back electromotive force, the mathematical model of the permanent magnet synchronous motor (PMSM) in step one is used to obtain: ,

[0045] In the formula To observe the rotor position, The first observed rotational speed can also be obtained through... get.

[0046] Step 4: Design of the outer loop load disturbance observer. An outer loop super-helical sliding mode observer is designed based on the mechanical dynamics equations to monitor load torque disturbances in real time, enabling effective estimation and compensation of the load disturbances.

[0047] Will Treat it as known input. , , Equal to the total disturbance Constructing a superspiral sliding mode observer to estimate Or direct estimation The rotational speed observation equation is derived from the mechanical motion equations of the permanent magnet synchronous servo drive system as follows:

[0048] In the formula The second observed speed is the mechanical speed of the motor. To observe the disturbance torque.

[0049] The observed disturbance moment value was obtained using the super-helical sliding mode control method. The observation equation for the disturbance moment is as follows:

[0050] in, For speed observation error, The result obtained using step three Achieve self-calibration; , , , , , , The coefficients of the constructed superspiral algorithm; , , , , The selection satisfies , >0, , , .

[0051] This structure is cascaded with the first stage, that is, the inner ring superhelical sliding mode observer and the outer ring superhelical sliding mode observer are connected in series to form a cascaded superhelical sliding mode observer, forming a two-stage observation link of "back potential-mechanical disturbance", which can converge quickly under parameter uncertainty and external load abrupt change.

[0052] Step 5: Implementation of motion control strategy. Using the above observations, a complete cascaded closed-loop control framework is formed to achieve closed-loop control of current and speed respectively.

[0053] The rotor position estimated by the inner ring ,speed The observed disturbance moment estimated by the outer ring It is cascaded into the control loop framework, specifically adopting a three-level control architecture of position-velocity-current, implementing current loop control, velocity loop control and position loop control based on field-oriented control, thereby achieving precise and stable servo motion control.

[0054] Specifically, such as Figure 1 The cascaded structure of "position regulator -> speed regulator -> current regulator" in the middle: the position regulator adjusts the rotor position according to the desired rotor position. Rotor position observed by the inner ring superhelical observatory The difference is calculated, and the output speed is given by PI control. ,according to With the first observed rotational speed The difference is calculated to obtain the speed error; the speed regulator performs PI control based on the speed error and outputs the desired electromagnetic torque command. Based on observed disturbance torque By introducing disturbance observation feedforward compensation and dividing by the motor torque coefficient, the desired q-axis current is obtained. : , Within the field-oriented control (FOC) framework, the desired d-axis current reference value is used. =0 Operation strategy outside the weak magnetic field zone. The difference between the desired current and the measured current is used to obtain the current error, and the current regulator performs PI control based on this error. The three-phase current values ​​measured by the current sensor are used... Finish Coordinate transformation yields the measured currents along the q-axis and d-axis.

[0055] Current regulator generation , .Will , After iPark transformation, , On one hand, drive pulses are generated via SVPWM for closed-loop operation; on the other hand, they are fed into the inner-loop super-spiral sliding mode observer. The control flow is shown below. Figure 2 : Current / voltage modeling -> Back EMF observation -> Angle / angular velocity calculation -> Mechanical disturbance observation -> Based on , , Complete the control of each link.

[0056] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A state-observation-based motion control method for a permanent magnet synchronous servo drive system, characterized by, The method comprises the following steps: In the inner loop super-helical sliding mode observer: obtaining the observed current according to the current observation equation of the permanent magnet synchronous motor; obtaining the current observation error according to the deviation between the observed current and the measured current; and estimating the observed back electromotive force by using the super-helical sliding mode control method based on the current observation error; Obtaining the observed rotor position and the first observed speed based on the observed back electromotive force estimated by the inner loop super-helical sliding mode observer; In the outer loop super-helical sliding mode observer: obtaining the second observed speed according to the speed observation equation of the permanent magnet synchronous motor; obtaining the speed observation error according to the deviation between the first observed speed and the second observed speed; and estimating the observed disturbance torque by using the super-helical sliding mode control method based on the speed observation error; The observed rotor position, the first observed speed and the observed disturbance torque are cascaded into the position-speed-current three-level control architecture to realize the servo motion control of the permanent magnet synchronous motor.

2. The state observation based permanent magnet synchronous servo drive system motion control method of claim 1, wherein, The current observation equation is as follows: wherein , are respectively axes, observed currents of the axes, , are respectively , first derivatives of the currents, , are respectively axes, observed back electromotive forces of the axes, , are respectively axes, given voltages of the axes; denotes a stator resistance, denotes a stator inductance.

3. The state observation based permanent magnet synchronous servo drive system motion control method of claim 2, wherein, The observed back electromotive force is estimated by using the super-helical sliding mode control method based on the current observation error, and specifically: wherein , are the measured currents of the axes, current observation error of the , , , are the measured currents of the axes, axes; t is the integration time variable, dt is the differentiation with respect to time, , , , , , , is the over-shoot algorithm coefficient, n takes the value or and satisfies , > 0, , , .

4. The state observation based permanent magnet synchronous servo drive system motion control method of claim 3, wherein, The observed rotor position and the first observed speed are obtained based on the observed back electromotive force estimated by the inner loop super-helical sliding mode observer, and specifically: wherein is the rotor position, is the first observed rotational speed, is the rotor flux.

5. The state observation based permanent magnet synchronous servo drive system motion control method of claim 4, wherein, The speed observation equation is as follows: wherein is the second observed rotational speed, is the first derivative of is the first derivative of is the observed disturbance torque; is the torque coefficient, is the q-axis current, is the viscous friction coefficient, is the rotor moment of inertia.

6. The state observation based permanent magnet synchronous servo drive system motion control method of claim 5, wherein, The observed disturbance torque is estimated by using the super-helical sliding mode control method based on the speed observation error, and specifically: wherein is the rotational speed observation error, ; , , , , , , is a supercoiling algorithm coefficient, satisfying , > 0, , , .

7. The state observation based permanent magnet synchronous servo drive system motion control method according to any one of claims 1-6, wherein, The observed rotor position, the first observed speed and the observed disturbance torque are cascaded into the position-speed-current three-level control architecture to realize the servo motion control of the permanent magnet synchronous motor, which comprises: The position error is obtained by subtracting the observed rotor position from the expected rotor position; the expected speed is output by the position regulator through PI control according to the position error; The speed error is obtained by subtracting the first observed speed from the expected speed output by the position regulator; the expected torque is output by the speed regulator through PI control according to the speed error; The expected current is obtained based on the expected torque and the observed disturbance torque; the current error is obtained by subtracting the measured current from the expected current; the expected voltage of the motor is output by the current regulator through PI control according to the current error, and is fed back to the inner loop super-helical sliding mode observer.

8. The state observation based permanent magnet synchronous servo drive system motion control method of claim 7, wherein, The expected current is obtained based on the expected torque and the observed disturbance torque, and specifically: , wherein, is the desired torque, is the observed disturbance torque, is the feedforward compensated torque, is the torque coefficient, is the q-axis desired current; the d-axis desired current is set to 0.

9. The state observation based permanent magnet synchronous servo drive system motion control method of claim 8, wherein, The current error is obtained by subtracting the measured current from the expected current, and specifically: According to the observed rotor position, the q-axis and d-axis measured currents are obtained by transforming the three-phase currents measured by the current sensor; then, the q-axis current error and the d-axis current error are obtained by subtracting the q-axis expected current from the q-axis measured current and subtracting the d-axis expected current from the d-axis measured current, respectively.

10. A state-observation-based permanent magnet synchronous servo drive system motion control system, characterized by, The processor is configured to execute the state observation-based permanent magnet synchronous servo drive system motion control method according to any one of claims 1-9.

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