Permanent magnet synchronous motor control method and system

Abstract

The invention relates to the technical field of motor control, and particularly provides a permanent magnet synchronous motor control method and system, and the method comprises the steps: building an expansion state model according to a speed loop model of a permanent magnet synchronous motor; designing a fixed-time adaptive observer based on the extended state model, and estimating total disturbance at fixed time; designing a linear control law based on the total disturbance, and compensating and suppressing the disturbance according to the linear control law; through the permanent magnet synchronous motor control method of the fixed-time self-adaptive observer, the disturbance estimation and elimination capability is enhanced, and the control performance of a speed ring of the permanent magnet synchronous motor is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor control, and specifically provides a permanent magnet synchronous motor control method and system of a fixed time adaptive observer. Background Art

[0002] Observer-based disturbance estimation and elimination control methods are widely used in motor control. Observers can quickly and accurately estimate internal parameter perturbations, external load disturbances, and other unmodeled dynamics, playing an extremely important role in achieving two-degree-of-freedom control.

[0003] Among them, traditional disturbance observers and extended state machines are the most common types of observers. However, they usually converge in infinite time, which cannot meet the needs of high-precision and high-performance control. In order to achieve accurate and fast estimation of disturbances, scholars have gradually developed finite-time observers and fixed-time adaptive observers. Among them, fixed-time adaptive observers have received widespread attention due to their ability to converge to the vicinity of the equilibrium point within a fixed time. However, the gain parameters of the fixed-time adaptive observer are constant and cannot be dynamically adjusted according to the estimation error, which has an adverse effect on the control situation where the motor state undergoes unknown changes.

[0004] Therefore, in order to solve the above problems, the present application proposes a permanent magnet synchronous motor control method and system. Summary of the invention

[0005] Aiming at the difficulty of obtaining fast response and high-precision tracking with a traditional fixed-time adaptive observer, the present invention provides a permanent magnet synchronous motor control method and system to achieve high-performance permanent magnet synchronous motor control.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows: In a first aspect, the present application provides a permanent magnet synchronous motor control method, comprising: According to the speed loop model of the permanent magnet synchronous motor, an expansion state model is established; Based on the extended state model, a fixed-time adaptive observer is designed to estimate the total disturbance at a fixed time; A linear control law is designed based on the total disturbance, and the disturbance is compensated and suppressed according to the linear control law.

[0007] Furthermore, the step of establishing the extended state model according to the speed loop model of the permanent magnet synchronous motor specifically includes the following steps: The speed loop model is expressed as: (1), in, is the motor moment of inertia; is the motor speed value; Motor speed value The derivative of is the viscous friction coefficient; is the moment coefficient; is the q-axis current; is the load torque; Convert (1) to: (2), in, is the nominal value of the control gain, is the nominal value of the moment coefficient, is the nominal value of the moment of inertia; is the reference value of the q-axis current, is the total disturbance.

[0008] Furthermore, the total disturbance It is expressed as: (3), The expansion state model including the perturbation differential term is established and expressed as: (4), in, is the first-order derivative of the total disturbance, The total disturbance The derivative of .

[0009] Furthermore, the step of designing a fixed-time adaptive observer based on the extended state model to estimate the total disturbance at a fixed time specifically includes the following steps: According to the extended state model, the fixed-time adaptive observer is expressed as: (5), in, and They are the estimation of motor speed and the estimation of total disturbance respectively; and are the estimated derivative of the motor speed and the estimated derivative of the total disturbance, respectively; is the speed estimation error; and is the gain of the fixed-time adaptive observer; and is the power exponent, ranging from and ; Represents a form of mathematical operation, specifically expressed as , , , ; is the speed estimation error The function is expressed as .

[0010] Furthermore, the step of designing a linear control law based on the total disturbance and compensating and suppressing the disturbance according to the linear control law specifically includes the following steps: According to the difference between the motor speed reference command and the motor speed value, the speed tracking error is constructed , expressed as:

[0011] in, is the motor speed reference command, is the motor speed value; Derivative of the velocity tracking error yields: (6), in, is the derivative of the motor speed reference command, is the derivative of the motor speed value; Based on the error feedback control strategy, the linear control law is designed: (7), in, is the speed control coefficient.

[0012] Furthermore, by combining equation (6) and equation (7), the reference value of the q-axis current is expressed as: (8), The fixed-time adaptive observer obtains an estimate of the motor speed Alternative motor speed value , an estimate of the total disturbance Alternative total disturbance , the linear control law is updated as: (9).

[0013] Furthermore, the fixed-time adaptive observer is used to achieve fixed-time convergence of the estimated state and the estimated disturbance.

[0014] In a second aspect, the present application provides a permanent magnet synchronous motor control system, comprising: Model building module: build an expansion state model based on the speed loop model of the permanent magnet synchronous motor; Observer module: Based on the extended state model, a fixed-time adaptive observer is designed to estimate the total disturbance at a fixed time; Control law module: a linear control law is designed based on the total disturbance, and the disturbance is compensated and suppressed according to the linear control law.

[0015] Compared with the prior art, the invention can achieve the following beneficial effects: (1) Through the extended state model, external disturbances and internal uncertainties are uniformly modeled as total disturbances, and disturbance compensation can be achieved without relying on an accurate mathematical model. Compared with the passive response error of traditional PI control, this application can actively observe and compensate for disturbances, significantly reduce the impact of disturbances on the control loop, and improve the stability of permanent magnet synchronous motors under complex working conditions.

[0016] (2) The fixed-time adaptive observer can complete the disturbance estimation within a preset fixed time. The convergence time is independent of the initial state, avoiding the limitations of traditional asymptotic convergence or finite-time convergence.

[0017] (3) Design a linear control law to achieve disturbance compensation and suppression. The linear control law reduces the reliance on high-performance processors and can be implemented on a low-cost controller, while reducing the need for sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 is a flow chart of a permanent magnet synchronous motor control method according to Embodiment 1; Figure 2 This is a block diagram of permanent magnet synchronous motor control based on fixed time adaptive observer in this embodiment 1; Figure 3 is a structural block diagram of a permanent magnet synchronous motor control method of this embodiment 1; Figure 4 A schematic diagram showing a speed curve comparison between a permanent magnet synchronous motor control method of Embodiment 1 and a conventional method under speed dynamics and sudden load interference; Figure 5 Schematic diagram of the structure of a permanent magnet synchronous motor control system according to the second embodiment. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the invention clearer, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the invention and do not constitute a limitation to the invention. Similar components in different embodiments use associated similar component numbers. In the following embodiments, many detailed descriptions are to enable the invention to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other components, materials, and methods. In some cases, some operations related to the invention are not shown or described in the specification, in order to avoid the core part of the invention being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0020] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0021] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0022] Example 1 See also Figure 1 , is a flow chart of a permanent magnet synchronous motor control method according to this embodiment; the specific steps include: S1: Establish an expansion state model based on the speed loop model of the permanent magnet synchronous motor.

[0023] In this embodiment, the speed loop model of the permanent magnet synchronous motor is expressed as: (1), in, is the motor moment of inertia; is the motor speed value; Motor speed value The derivative of is the viscous friction coefficient; is the moment coefficient; is the q-axis current; is the load torque.

[0024] In a surface mounted permanent magnet synchronous motor, the torque coefficient It is expressed as: , in, is the number of motor pole pairs, is the permanent magnet flux.

[0025] Convert (1) to: (2), in, is the nominal value of the control gain, is the nominal value of the moment coefficient, is the nominal value of the moment of inertia; is the reference value of the q-axis current, is the total disturbance.

[0026] Total disturbance It is expressed as: (3), The expansion state model including the perturbation differential term is established and expressed as: (4), in, is the first-order derivative of the total disturbance, The total disturbance The derivative of .

[0027] S2: Based on the extended state model, a fixed-time adaptive observer is designed to estimate the total disturbance in fixed time.

[0028] In this embodiment, according to the extended state model (4), the fixed-time adaptive observer is expressed as: (5), in, and They are the estimation of motor speed and the estimation of total disturbance respectively; and are the estimated derivative of the motor speed and the estimated derivative of the total disturbance, respectively; is the speed estimation error; and is the gain of the fixed-time adaptive observer; and is the power exponent, ranging from and ; Represents a form of mathematical operation, specifically expressed as , , , ; is the speed estimation error The function is expressed as , from this we can see that , The size of the total gain of the observer can be adaptively adjusted according to the error state to achieve fixed-time adaptive estimation.

[0029] S3: Design a linear control law based on the total disturbance, and compensate and suppress the disturbance according to the linear control law.

[0030] In this embodiment, the speed tracking error is constructed according to the difference between the motor speed reference command and the motor speed value. , expressed as:

[0031] in, is the motor speed reference command, is the motor speed value; Taking the derivative of the velocity tracking error, we get: (6), in, is the derivative of the motor speed reference command, is the derivative of the motor speed value; Based on the error feedback control strategy, the linear control law is designed: (7), in, is the speed control coefficient.

[0032] Combining equation (6) and equation (7), the reference value of the q-axis current is expressed as: (8), The motor speed estimate obtained by the fixed-time adaptive observer is Alternative motor speed value , an estimate of the total disturbance Alternative total disturbance , the linear control law is updated as: (9).

[0033] See also Figure 2 , is a control block diagram of a permanent magnet synchronous motor based on a fixed time adaptive observer according to Embodiment 1. The fixed time adaptive observer and the current controller act on the speed loop of the permanent magnet synchronous motor, and the linear control law is used to realize the compensation and suppression of disturbances.

[0034] See also Figure 3 , is a structural block diagram of a permanent magnet synchronous motor control method of this embodiment 1. The transmission paths of various signals and the interaction relationships between modules are marked.

[0035] See also Figure 4 , which is a schematic diagram comparing the speed curves of a permanent magnet synchronous motor control method of this embodiment 1 and a traditional method in speed dynamics and sudden load interference. Specifically, when the speed reference command is 100 rad / s, the speed curves of the control method based on the traditional observer and the control method based on the fixed time adaptive observer proposed in the present application in speed dynamics and sudden load interference. It can be seen that in speed dynamics, the method proposed in the present application has faster speed response dynamics and has a smaller speed drop when the same load interference is suddenly added. Therefore, a permanent magnet synchronous motor control method of the present application has obvious advantages.

[0036] To summarize, in this embodiment 1, an extended state model containing a disturbance differential term is first established based on the speed loop model of the permanent magnet synchronous motor; a fixed-time adaptive observer is designed based on the established extended state model to achieve fixed-time convergence of the estimated state and the estimated disturbance; and finally, a linear control law is designed to achieve compensation and suppression of the disturbance.

[0037] Example 2 See also Figure 5 , is a structural diagram of a permanent magnet synchronous motor control system of this embodiment; the specific contents include: Model building module: build an expansion state model based on the speed loop model of the permanent magnet synchronous motor; Observer module: Based on the extended state model, a fixed-time adaptive observer is designed to estimate the total disturbance at a fixed time. Control law module: Design a linear control law based on the total disturbance, and compensate and suppress the disturbance according to the linear control law.

[0038] In this embodiment, an extended state model containing a disturbance differential term is obtained through a model building module, and a fixed-time adaptive observer is designed based on the extended state model by an observer module to achieve fixed-time convergence of the estimated state and the estimated disturbance; the control law module designs a linear control law based on an error feedback control strategy to compensate for the disturbance and generate a q-axis current reference. The proposed control system realizes rapid and accurate estimation and compensation of disturbances in a permanent magnet synchronous motor system, and obtains rapid response and high-precision tracking, thereby improving the control performance of the permanent magnet synchronous motor speed loop.

[0039] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0040] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A permanent magnet synchronous motor control method, characterized in that: include: According to the speed loop model of the permanent magnet synchronous motor, an expansion state model is established; Based on the extended state model, a fixed-time adaptive observer is designed to estimate the total disturbance at a fixed time; A linear control law is designed based on the total disturbance, and the disturbance is compensated and suppressed according to the linear control law.

2. A permanent magnet synchronous motor control method according to claim 1, characterized in that: The step of establishing the extended state model according to the speed loop model of the permanent magnet synchronous motor specifically includes the following steps: The speed loop model is expressed as: （1）， in, is the motor moment of inertia; is the motor speed value; Motor speed value The derivative of is the viscous friction coefficient; is the moment coefficient; is the q-axis current; is the load torque; Convert (1) to: （2）， in, is the nominal value of the control gain, is the nominal value of the moment coefficient, is the nominal value of the moment of inertia; is the reference value of the q-axis current, is the total disturbance.

3. A permanent magnet synchronous motor control method according to claim 2, characterized in that: The total disturbance It is expressed as: （3）， The expansion state model including the perturbation differential term is established and expressed as: （4）， in, is the first-order derivative of the total disturbance, The total disturbance The derivative of .

4. A permanent magnet synchronous motor control method according to claim 3, characterized in that: The step of designing a fixed-time adaptive observer based on the extended state model to estimate the total disturbance at a fixed time specifically includes the following steps: According to the extended state model, the fixed-time adaptive observer is expressed as: (5), in, and They are the estimation of motor speed and the estimation of total disturbance respectively; and are the estimated derivative of the motor speed and the estimated derivative of the total disturbance, respectively; is the speed estimation error; and is the gain of the fixed-time adaptive observer; and is the power exponent, ranging from and ; Represents a form of mathematical operation, specifically expressed as , ， ， ; is the speed estimation error The function is expressed as .

5. A permanent magnet synchronous motor control method according to claim 4, characterized in that: The step of designing a linear control law based on the total disturbance and compensating and suppressing the disturbance according to the linear control law specifically includes the following steps: According to the difference between the motor speed reference command and the motor speed value, the speed tracking error is constructed , expressed as: in, is the motor speed reference command, is the motor speed value; Derivative of the velocity tracking error yields: （6）， in, is the derivative of the motor speed reference command, is the derivative of the motor speed value; Based on the error feedback control strategy, the linear control law is designed: （7）， in, is the speed control coefficient.

6. A permanent magnet synchronous motor control method according to claim 5, characterized in that: Combining equation (6) and equation (7), the reference value of the q-axis current is expressed as: （8）， The fixed-time adaptive observer obtains an estimate of the motor speed Alternative motor speed value , an estimate of the total disturbance Alternative total disturbance , the linear control law is updated as: （9）。 7. A permanent magnet synchronous motor control method according to claim 6, characterized in that: The fixed-time adaptive observer is used to achieve fixed-time convergence of estimated states and estimated disturbances.

8. A permanent magnet synchronous motor control system, characterized in that: include: Model building module: build an expansion state model based on the speed loop model of the permanent magnet synchronous motor; Observer module: Based on the extended state model, a fixed-time adaptive observer is designed to estimate the total disturbance at a fixed time; Control law module: a linear control law is designed based on the total disturbance, and the disturbance is compensated and suppressed according to the linear control law.

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