A slip-mode extended state observer compound control permanent magnet reluctance motor phase-locked loop device and control strategy

Abstract

This invention discloses a phase-locked loop (PLL) device and control strategy for a permanent magnet reluctance motor (PML) using a sliding mode-expanded state observer composite control system. The method includes: Step S1: Establishing a mathematical model of the PLL based on its electrical parameters; Step S2: Real-time monitoring of the PLL's input signal using an expanded state observer, estimating the measurement noise in the input signal as a total disturbance, and generating a clean position error signal after filtering out the total disturbance; Step S3: Inputting the clean position error signal to a sliding mode controller, which constructs a sliding surface based on the clean position error signal and outputs control signals to calculate the rotor position and speed; and generating a drive signal based on the calculated rotor position and speed to control the operation of the PLL. This invention, through the synergistic effect of sliding mode control and an expanded state observer, significantly improves the noise immunity of the PLL while ensuring its fast dynamic response, making it suitable for high-reliability scenarios such as motor drives.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet reluctance motor control technology, specifically to a phase-locked loop (PLL) device and control strategy for permanent magnet reluctance motors using a sliding mode-expanded state observer composite control. Addressing the problem of insufficient accuracy of traditional PLLs under noise and disturbance environments, this invention proposes a composite control architecture that combines an extended state observer with sliding mode control. By designing an extended state-space model to estimate the total system disturbance in real time, and utilizing a nonlinear observer to output a purified error signal, the invention significantly improves the anti-interference capability and tracking accuracy of the PLL under complex operating conditions. Background Technology

[0002] Permanent magnet reluctance motors (PMMs) utilize the reluctance torque of permanent magnets, offering advantages such as high efficiency and high power density. However, due to the unique rotor structure, PMMs exhibit a significant salient pole effect. Existing sensorless control technologies typically employ phase-locked loops (PLLs) to estimate rotor position and speed. However, the salient pole effect results in high-frequency harmonic interference caused by reluctance torque in the back electromotive force, and the motor operation is subject to unknown dynamics such as measurement noise and sudden load torque changes. While traditional sliding mode control is robust to parameter perturbations, its inherent chattering phenomenon leads to high-frequency switching of control inputs, causing system oscillations and noise. Therefore, achieving high-precision, low-chattering PLL through algorithm fusion without increasing hardware costs, and effectively suppressing high-frequency harmonic interference caused by the salient pole effect, is a pressing technical challenge.

[0003] To address the aforementioned problems, this invention proposes a phase-locked loop device and control strategy for permanent magnet reluctance motors with sliding mode-expanded state observer composite control. This deep coupling mechanism directly uses the signal from the expanded state observer, which filters out disturbances, as the sliding mode input, significantly improving the system's noise immunity and engineering application value under complex operating conditions. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a phase-locked loop control method and system for a permanent magnet reluctance motor using a sliding mode-expanded state observer composite control; to achieve the above objective, this invention adopts the following technical solution: 1. A phase-locked loop control method for a permanent magnet reluctance motor using a sliding mode-expanded state observer composite control, comprising: Step S1: Establish a mathematical model of the dq axis of the permanent magnet reluctance motor, which is constructed based on the electrical parameters of the motor; Step S2: Monitor the input signal of the phase-locked loop in real time through the extended state observer, estimate the measurement noise and unknown dynamics in the input signal as the total disturbance, and generate a pure position error signal after filtering out the total disturbance based on this. Step S3: The pure position error signal is directly input to the sliding mode controller. The sliding mode controller constructs a sliding surface based on the pure position error signal and outputs control quantities to calculate the rotor position and speed. A drive signal is generated based on the calculated rotor position and speed to control the operation of the permanent magnet reluctance motor.

[0005] Preferably, in step S2, the extended state observer expands the total disturbance of the system into a new state variable, constructs a higher-order observer model, actively tracks the useful components in the input signal through a nonlinear feedback mechanism, and simultaneously estimates and absorbs noise and total disturbance in real time. The weight of the estimation error is dynamically adjusted using a nonlinear function to improve the tracking ability of high-frequency noise and sudden disturbance.

[0006] Preferably, in step S3, the sliding mode controller inside the phase-locked loop is designed to construct a sliding surface with the position estimation error as the state variable and to use Sigmoid as the nonlinear switching function. By reasonably adjusting the function parameters, the high-frequency chattering problem in traditional sliding mode control can be effectively suppressed while ensuring the system's fast dynamic response.

[0007] 2. A phase-locked loop control system for permanent magnet reluctance motors with sliding mode-expanded state observer composite control. This invention also proposes a phase-locked loop control system for a permanent magnet reluctance motor with sliding mode-expanded state observer composite control, comprising the following modules: (1) Mathematical model construction module This module is used to establish a mathematical model for the control system based on the voltage, current, flux linkage, and torque equations of a permanent magnet reluctance motor. Through precise mathematical calculations, this module integrates various equations of the motor into a unified model, providing basic model support for the analysis and control of subsequent modules, and ensuring that the entire control system is designed based on accurate motor characteristics.

[0008] (2) Problem Analysis Module The task is to analyze the problems of traditional phase-locked loops in the operation of permanent magnet reluctance motors; through theoretical derivation and experimental data, to deeply analyze the influence mechanism of parameter perturbation, external disturbance and measurement noise on the performance of traditional phase-locked loops, and to establish the corresponding quantitative relationship, so as to provide clear problem guidance and quantitative basis for the design of subsequent sliding mode controllers and extended state observers.

[0009] (3) Sliding mode controller design module This module focuses on the design of the sliding mode controller; it constructs an integral sliding surface using the rotor electrical angle estimation error as the state variable, and generates control signals through precise calculations using a specific nonlinear switching function; by setting parameters reasonably, this module ensures that the sliding mode controller can achieve fast and stable rotor angle tracking under complex working conditions, while effectively suppressing chattering problems and improving the dynamic response performance and steady-state accuracy of the system.

[0010] (4) Extended State Observer Design Module This module introduces an extended state observer, which expands the total system disturbance into new state variables and constructs an observer model. Through a nonlinear feedback mechanism, it processes the input signal using a specific nonlinear function, estimating and absorbing noise and total disturbance in real time. This module can extract useful components from the input signal and output a purified signal, providing high-quality feedback for the sliding mode controller and enhancing the anti-interference capability of the entire control system. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0012] Figure 1 Comparison of signals before and after noise removal for the extended observer; Figure 2 Error diagram for speed calculation using PI control in phase-locked loop; Figure 3 A comparison chart of the calculated and actual rotational speeds for phase-locked loops using sliding mode control without an expanded observer; Figure 4 Error diagram for calculating the rotational speed of a phase-locked loop using sliding mode control without an expanded observer; Figure 5 A comparison diagram of the calculated rotor position and the actual rotor position for phase-locked loop (PLL) control using sliding mode-expanded observer composite control. Figure 6 A comparison chart of the calculated speed and the actual speed for phase-locked loop using sliding mode-expanded observer composite control; Figure 7 Error diagram for speed calculation of phase-locked loop using sliding mode-expanded observer composite control; Figure 8 This is a structural diagram of a phase-locked loop control device for a permanent magnet reluctance motor with a sliding mode-expanded state observer composite control. Figure 9 This is a flowchart of a phase-locked loop control method for a permanent magnet reluctance motor using a sliding mode-expanded state observer composite control. Detailed Implementation

[0013] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0014] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Example 1: As Figure 9 As shown, this embodiment of the invention provides an improved method for phase-locked loop control of a permanent magnet reluctance motor using a sliding mode-expanded state observer composite control, characterized by the following steps: Step S1: Establish a mathematical model of the permanent magnet reluctance motor, which is constructed based on the motor's electrical parameters; Step S2: Monitor the input signal of the phase-locked loop in real time through the extended state observer, estimate the measurement noise in the input signal as the total disturbance, and generate a pure position error signal after filtering out the total disturbance based on this. Step S3: Input the pure position error signal to the sliding mode controller. The sliding mode controller constructs a sliding surface based on the pure position error signal and outputs control quantities to calculate the rotor position and speed. Based on the calculated rotor position and speed, a drive signal is generated to control the operation of the permanent magnet reluctance motor.

[0015] As one embodiment of the present invention, the phase-locked loop structure of the permanent magnet reluctance motor under sliding mode-expansion state observer composite control is as follows: Figure 8 As shown, the input of the phase-locked loop is the back electromotive force output from the previous stage. The mathematical operation result of the back electromotive force and the trigonometric function is used as the input of the extended state observer. After real-time noise filtering, the signal is used as the input of the sliding mode controller. By adjusting the control signal on the sliding mode surface, the speed and phase can be controlled.

[0016] This invention relates to the field of signal processing technology, specifically a real-time input signal purification method based on a second-order extended state observer (ESO). The ESO used is a second-order system, and its observer's dynamic equations are as follows: (1) in: It is observation error; and It is the observer gain, which is determined by the observer bandwidth. The decision is made; fal() is a nonlinear function used to handle observation errors. It combines linear and nonlinear characteristics to improve robustness to noise and disturbances, and takes the following form: (2) in It is a non-linear exponent when It exhibits the characteristic of large gain with small error and small gain with large error; It is a linear interval threshold used for smooth transitions.

[0017] Since the system can only process discrete data and operations, the continuous-time system is discretized using Equation (1) through the Euler method: (3) in Ts It is the sampling time; from equation (3), the purified signal can be obtained as follows: That is, the estimation of the true phase error; the perturbation estimation is... This includes noise and unmodeled dynamics; the purification effect is as follows: Figure 1 As shown.

[0018] The improved phase-locked loop in this invention relates to the field of nonlinear control technology, specifically a sliding mode control method. Traditional phase-locked loops use a PI controller, and the speed calculation waveform is shown in the figure. However, they suffer from drawbacks such as large calculation errors. Figure 2 As shown; the sliding mode controller used achieves rapid convergence of the system state by designing a sliding surface, making the sliding surface approximate the estimation error of the rotor position, thus exhibiting strong robustness.

[0019] The improved phase-locked loop using sliding mode control is shown in the figure. The mathematical operation structure of back electromotive force and rotor position estimation is used as the input for sliding mode control. However, chattering occurs in the input, leading to chattering in the speed calculation. Figure 3 , 4 As shown, an extended observer is selected before the sliding mode controller to filter out interference. It is known that the input of the extended observer is the error signal without signal purification. The expression can be written as: (4) In the formula d est It is noise interference. After filtering out the interference by expanding the observer, an ideal clean signal is obtained. The expression can be written as: (5) The improved phase-locked loop (PLL) employing a combined sliding mode and extended observer control structure is shown in the figure. The input to the sliding mode is the signal purified by the extended state observer. S Defined as: (6) It is known that when When the value is very small, It can be approximately equal to Therefore, when the back electromotive force is accurately estimated, the sliding surface S is approximately equal to the error in the rotor position estimation, i.e.: (7) Therefore, the sliding surface S is essentially a position error signal; driving S to approach zero means forcing the position estimation error to approach zero; the control law uses the sigmoid function to suppress chattering. (8) in It is the estimated electrical angular velocity output by the system. k This is the sliding film gain; the estimated rotor position is obtained by integrating the estimated angular velocity. (9) The solution effect of phase-locked loop using sliding mode-expanded observer composite control is as follows: Figure 5 , 6 As shown in Figure 7; now, stability analysis is performed, and the candidate Lyapunov function is defined as: (10) This function is valid if and only if That is, when the position estimation error is equal to 0, S=0, V=0, and the function is positive definite; take the reciprocal of time with respect to V: (11) Now we need to ask Using the chain rule: (12) Depend on Differentiating, we get: (13) right Differentiation yields: (14) Substituting equations (13) and (14) into equation (11), we get: (15) When the position error satisfies hour, , It is a positive coefficient, therefore, to make the system stable, that is... Then the following condition is met: (16) When S > 0, divide both sides by S simultaneously: (17) When S < 0, divide both sides by S simultaneously: (18) S=0 is the equilibrium point, which is outside the scope of dynamic stability analysis; therefore: (19) Since |Sigmiod(S)|≤1, then: (20) Therefore That is, when At that time, the system was stable.

[0020] Example 2: This embodiment of the invention also provides a system architecture and hardware implementation of a permanent magnet reluctance motor phase-locked loop device with sliding mode-expanded state observer composite control, including: a mathematical model construction unit, an expanded state observer module, a sliding mode control module, and a signal generation module; (I) Hardware platform: The core control unit of this system is implemented using a digital signal processor model TMS320F28377D, and the drive circuit is a 10KW permanent magnet reluctance motor drive circuit. (II) Module Connection Relationships: The mathematical model construction unit is configured to establish a mathematical model of the dq axis based on the salient pole effect and electrical parameters of the permanent magnet reluctance motor; the extended observer module is configured to estimate the measurement noise, load torque mutation, and high-frequency harmonics caused by the salient pole effect in the signal as the total disturbance; the sliding mode module has its input directly connected to the output of the extended observer module. The sliding mode module receives the pure position error signal z1 output by the extended observer, constructs the sliding surface, and calculates the rotor electrical angle. and electric angular velocity Signal generation module: will generate the solved signal. and The signal is input into the PI controller, and then through the deadbeat current prediction controller, anti-Parker change and space vector pulse width modulation module to generate the PWM signal to drive the inverter.

[0021] Example 3: This embodiment of the invention also provides a simulation verification of a phase-locked loop for a permanent magnet reluctance motor under sliding mode-expanded state observer composite control. In order to verify the beneficial effects of the invention, simulation experiments were conducted in the Matlab / Simulink environment and compared with traditional control strategies. (I) Simulation conditions: The motor is set to a speed of 600 rpm. A sudden load is applied at t=0.5s. The comparison objects are a permanent magnet reluctance motor phase-locked loop using traditional PI control, a permanent magnet reluctance motor phase-locked loop using sliding mode control without an expanded observer, and the permanent magnet reluctance motor phase-locked loop of this invention using an expanded observer-sliding mode composite control. (II) Simulation Result Analysis: (1) The error in speed calculation using traditional PI control in the phase-locked loop of the permanent magnet reluctance motor is as follows: Figure 2 As shown, the speed error reached 118 r / min during the startup of the permanent magnet reluctance motor; the speed calculation error diagram of the phase-locked loop using sliding mode control without an expanded observer is shown in the figure below. Figure 3 As shown, the speed error of the permanent magnet reluctance motor during startup is only 39 r / min. The comparison between the calculated speed and the actual speed using sliding mode control without an expanded observer in the phase-locked loop is shown in the figure below. Figure 4 As shown, when the permanent magnet reluctance motor is running stably, the speed fluctuation reaches ±1 r / min. Although the speed error is reduced when the permanent magnet reluctance motor starts, the speed fluctuation is still large. (2) As can be seen from (1), the PI control used in the traditional phase-locked loop of permanent magnet reluctance motor has a large error in speed calculation. After the improvement of the scheme by replacing PI control with sliding mode control, the speed error is significantly reduced. However, the speed jitter is large when the motor is running stably. Now, the phase-locked loop using sliding mode control is improved by introducing an extended observer into the phase-locked loop. The extended observer filters out the interference signal of the input signal. The filtered signal is then input into the sliding mode control for speed calculation. Figure 5 This is a comparison chart of the calculated rotor position and the actual rotor position for phase-locked loop (PLL) control using a sliding mode-expanded observer composite control. Figure 6 This is a comparison chart of the calculated and actual rotational speeds for phase-locked loop (PLL) control using a sliding mode-expanded observer composite control. Figure 7 The diagram shows the speed calculation error of the phase-locked loop (PLL) using sliding mode-expanded observer composite control. The improved PLL with extended observer-sliding mode composite control has a speed error of only 35 r / min during the startup of the permanent magnet reluctance motor, and a speed jitter of only ±0.09 r / min during stable motor operation. Experimental data proves that this invention, through the series composite structure of "expanded observer filtering out total disturbance + sliding mode expansion robust calculation" and combined with the Sigmoid function, effectively solves the calculation error problem of traditional PLL using PI control and the chattering dilemma of sliding mode control.

[0022] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A phase-locked loop device and control strategy for permanent magnet reluctance motor with sliding mode-expanded state observer composite control. Its features include the following steps: Step S1: Establish a mathematical model of the permanent magnet reluctance motor, which is constructed based on the motor's electrical parameters; Step S2: Monitor the input signal of the phase-locked loop in real time through the extended state observer, estimate the measurement noise in the input signal as the total disturbance, and generate a pure position error signal after filtering out the total disturbance based on this. Step S3: Input the pure position error signal to the sliding mode controller. The sliding mode controller constructs a sliding surface based on the pure position error signal and outputs control quantities to calculate the rotor position and speed. Based on the calculated rotor position and speed, a drive signal is generated to control the operation of the permanent magnet reluctance motor.

2. The control method according to claim 1, characterized in that: The input signal of the phase-locked loop is the q-axis current component or back electromotive force component of the permanent magnet reluctance motor; the state variables of the extended state observer include the position error estimate and the total disturbance estimate, wherein the total disturbance estimate includes measurement noise and high-frequency harmonic interference caused by the salient pole effect.

3. The control method according to claim 1, characterized in that: The sliding surface is defined as ,in The pure position error signal is used; the sliding mode control law adopts a reaching law form: ,in For equivalent control items, The sliding mode controller is configured to increase the nonlinear gain to accelerate convergence when the system error is large, and decrease the gain to suppress chattering when the error is small.

4. The control strategy according to claim 3, characterized in that: The switching control term uses the Sigmoid function instead of the traditional sign function to reduce chattering in sliding mode control; the expression for the Sigmoid function is as follows: , This is the adjustment coefficient.

5. The control method according to claim 1, characterized in that, The parameter configuration and discretization implementation of the extended state observer includes: setting the observer bandwidth frequency as... The observer gain is then configured as follows: , Set the nonlinear function parameters and the threshold for the linear interval; perform iterative calculations using a discretized formula: , ;in, The sampling period is This is the original position error signal. This is the estimated value of the pure position error signal. This is the estimated total disturbance.

6. The control method according to any one of claims 1 to 5, characterized in that: The extended state observer and the sliding mode controller form a series structure, that is, the output of the extended state observer is directly connected to the input of the sliding mode controller, forming a closed-loop control link of "total disturbance estimation-signal purification-robust solution".

7. A phase-locked loop device for a permanent magnet reluctance motor, characterized in that: A mathematical model building unit is used to establish a mathematical model of the dq axis based on the electrical parameters of the permanent magnet reluctance motor; an extended state observer module receives the original input signal from the phase-locked loop at its input end, is configured to estimate the measurement noise and unknown dynamics in the signal as the total disturbance, and output a pure position error signal after filtering out the total disturbance; a sliding mode control module is directly connected to the output end of the extended state observer module at its input end, and is configured to receive the pure position error signal, construct a sliding surface, and output control quantities to solve for the rotor position and speed; The signal generation module is connected to the output of the sliding mode control module and is used to generate the final drive signal based on the calculated rotor position and speed.

8. The permanent magnet reluctance motor phase-locked loop device according to claim 7, characterized in that: The extended state observer module is specifically configured to: define state variables. The estimated value of the pure position error signal, state variable This is an estimate of the total disturbance; based on a nonlinear function. Alternatively, the Sigmoid function can be used to process the error; the estimated value is output in real time through the state update equation, where the observer gain is related to the observer bandwidth frequency.

9. The permanent magnet reluctance motor phase-locked loop device according to claim 7, characterized in that: The sliding mode control module includes: a sliding mode surface definition unit, used to use the pure position error signal as the sliding mode surface variable; a control law calculation unit, used to calculate the equivalent control term and the switching control term, wherein the switching control term uses the Sigmoid function to suppress chattering; the output of the sliding mode control module is directly fed back to the voltage-controlled oscillator or integrator of the phase-locked loop to adjust the motor phase.

10. The permanent magnet reluctance motor phase-locked loop device according to claim 7, characterized in that: The extended state observer module and the sliding mode control module are directly connected in series at the hardware level through a digital signal processor or a field-programmable gate array, without the need for intermediate buffers or additional filtering stages.

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