Method for controlling rotating speed tracking consistency of multiple permanent magnet synchronous motors based on local information interaction

Abstract

The invention provides a multi-permanent magnet synchronous motor rotating speed tracking consistency control method based on local information interaction, and relates to the technical field of multi-permanent magnet synchronous motor rotating speed cooperative control. A vector control subsystem of a single motor in a multi-permanent magnet synchronous motor rotating speed cooperative control system is regarded as an intelligent agent, the intelligent agent interacts rotating speed information with a neighbor intelligent agent according to a designed communication topology, and expected q-axis current is updated in real time through a rotating speed tracking consistency protocol; therefore, the rotating speed tracking consistency is realized based on the local rotating speed information, and a rotating speed tracking controller does not need to be independently designed, so that mutual restriction of rotating speed tracking performance and synchronization performance can be avoided; in addition, distributed control has the advantages of simple structure, high flexibility, high expansibility and the like; the disturbance observer designed by the invention has continuous observation output values, and the system buffeting can be further weakened and the system robustness can be enhanced by utilizing the observer to estimate unknown disturbance and carry out feedforward compensation.

Description

Technical Field

[0001] The present invention relates to the technical field of coordinated speed control of multiple permanent magnet synchronous motors, and in particular to a speed tracking consistency control method for multiple permanent magnet synchronous motors with local information interaction. Background Art

[0002] Multi-motor speed coordinated control has gradually become a key technology for modern industrial production and equipment manufacturing. Research on improving the performance of multi-motor coordinated control systems has become a hot and difficult issue in the current motor control field. Permanent magnet synchronous motors have been widely used in industry due to their high power density and high efficiency. Therefore, research on the speed coordinated control of multiple permanent magnet synchronous motors has important theoretical significance and engineering application value.

[0003] Traditional multi-motor synchronization mainly studies synchronization control technology from two dimensions: synchronization control structure and control algorithm, in order to obtain system tracking performance and synchronization accuracy. Among them, master control is the simplest multi-motor speed synchronization control strategy, but due to the independence of the motor speed closed-loop control subsystems, it is difficult for the multi-motor system to maintain high synchronization accuracy and low robustness. In master-slave control, the master motor cannot track the speed change of the slave motor, and there is a large transmission delay. By introducing a coupling structure, cross-coupling control can further improve the synchronization accuracy, but the cross-coupling control method is only applicable to the speed synchronization control of two motors. In engineering practice, the deviation coupling control strategy is often used to achieve multi-motor speed coordinated control. However, when the number of motors increases, the complexity of the deviation coupling control structure and synchronization algorithm increases significantly; secondly, the multi-motor speed synchronization control based on deviation coupling needs to obtain the speed information of all motors in the system when updating the speed synchronization control algorithm at the sampling point, which will put forward high requirements on the communication and data processing capabilities of the system. In addition, the conventional multi-motor system with synchronous control structure combined with intelligent control method has problems such as complex structure and large amount of calculation, which cannot meet the control system's requirements for flexibility, reliability and self-organization ability. Therefore, it is of great engineering value to propose a new multi-permanent magnet synchronous motor speed collaborative control strategy based on local information interaction and with the characteristics of flexibility, scalability and robustness. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a speed tracking consistency control method for multiple permanent magnet synchronous motors with local information interaction in view of the shortcomings of the above-mentioned prior art, so as to avoid the dependence of the speed cooperative controller on the global speed information. The method uses the speed tracking consistency protocol to realize speed tracking control and synchronous control at the same time, and has the characteristics of flexibility, scalability and robustness.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A speed tracking consistency control method for multiple permanent magnet synchronous motors with local information interaction is disclosed. The method regards the vector control subsystem of a single motor in the speed cooperative control system of multiple permanent magnet synchronous motors as an intelligent agent. The intelligent agent exchanges speed information with its neighboring intelligent agents according to the designed communication topology, and updates the expected q-axis current in real time through the speed tracking consistency protocol. The method specifically includes the following steps:

[0007] Step 1: Design a virtual leader and describe its mathematical model as:

[0008]

[0009] Among them, ω m,0 is the virtual mechanical angular velocity, i q,0 is the virtual q-axis current, P n , ψ and J are the number of magnetic pole pairs, permanent magnet flux and moment of inertia of the real motor respectively; d / dt represents the differential operator; definition where ω ref is the speed given signal; the virtual q-axis current is designed as:

[0010]

[0011] Among them, k p is the proportional gain, k I is the integral gain;

[0012] Step 2: Design a directed communication topology;

[0013] In the multi-PMSM speed cooperative control system, the local vector control subsystems of N motors are regarded as N independent nodes and the set Indicates; node v0 represents the virtual leader; (v i ,v j ) represents the slave node v i To node v j There is an edge, namely node v j Can get node v i Speed ​​information; define scalar a ij Represents the slave node v j To node v i The connection weight of j ,v i ) exists, then a ij =1, otherwise a ij =0;

[0014] Define a directed communication topology graph in is the edge set, the adjacency matrix Represents node v i The set of neighbor nodes of

[0015] Define the Laplacian matrix When i=j, When i≠j, l ij =-a ij ;

[0016] Step 3: Design a speed tracking consistency protocol;

[0017] Consider a directed communication topology graph The vector control subsystem of a single motor is regarded as an intelligent agent, and the desired q-axis current is regarded as a speed tracking consistency protocol; the intelligent agent calculates and updates its own desired q-axis current according to the speed information obtained from neighboring intelligent agents, thereby achieving speed tracking consistency.

[0018] Furthermore, the step 3 specifically includes the following steps:

[0019] Step 3.1: Design a tracking consistency protocol;

[0020] Considering the influence of parameter perturbation, the mathematical model of permanent magnet synchronous motor is described as:

[0021]

[0022] Among them, ω m,i is the mechanical angular velocity; i q,i is the component of the stator current on the q axis; the subscript i is the motor number, i = 1, 2, ..., N; f ω,i is the speed disturbance, including friction torque and load disturbance, f ω ,i=-(Bω m,i +T L,i ) / J,T L,i is the load torque, B is the viscous friction coefficient;

[0023] The consistency error is defined as:

[0024] e i =ω m,i -ω m,0 (4)

[0025] Define relative error:

[0026]

[0027] Based on directed communication topology graph Design speed tracking consistency protocol:

[0028]

[0029] Among them, positive constants ρ1, ρ2, ρ3 and ρ4 are adjustable parameters; p and q are both positive odd numbers, and p<q; is the speed disturbance f ω,i An estimated value of

[0030] Step 3.2: Estimate the unknown speed disturbance f ω,i ;

[0031] Design the disturbance observer shown in equation (7) to f ω,i Make an estimate and feed-forward compensation:

[0032]

[0033] Among them, 0<γ<1, η>1, c3>0 are observer parameters; and is the adaptive gain; parameters κ1 and κ2 are positive constants used to adjust and Adaptive law of and is a positive number, representing and Reference value of; define variable ζ ω,i is an auxiliary variable and satisfies

[0034] Step 3.3: Design the current controller;

[0035] In the dq rotating coordinate system, based on i d = 0 and considering the influence of parameter perturbation, the current state equation of the multi-permanent magnet synchronous motor system is described as:

[0036]

[0037] Among them, u q,i is the component of the stator voltage on the q axis; R and L are the stator resistance and stator inductance respectively; f q,i represents the current disturbance, and its expression is:

[0038]

[0039] Among them, ΔR, ΔL and Δψ represent the change of stator resistance, stator inductance and permanent magnet flux linkage respectively;

[0040] The current tracking error is defined as And design the integral sliding surface:

[0041]

[0042] Where σ is a positive constant used to adjust the current tracking error The convergence speed of

[0043] make and f q,i =0, and substitute it into the current state equation (8) to obtain the sliding mode equivalent control law:

[0044]

[0045] The current controller output, i.e., the q-axis voltage, is designed as:

[0046]

[0047] in, is the sliding mode switching control law; the integral sliding mode surface formula (10) is derived, and the q-axis voltage formula (12) is substituted into it to obtain:

[0048]

[0049] The current disturbance observer shown in formula (14) is designed to observe the current disturbance f q,i Make an estimate:

[0050]

[0051] in, is the current disturbance f q,i Estimated value of; variable ζ q,i is an auxiliary variable and satisfies

[0052] Based on the current disturbance observer (14), the sliding mode switching control law is designed as:

[0053]

[0054] Among them, the adjustable parameters 0<r<1, s>1, k1, k2 and k3 are all positive constants.

[0055] The beneficial effect of adopting the above technical solution is that the speed tracking consistency control method of multiple permanent magnet synchronous motors with local information interaction provided by the present invention regards the vector control subsystem of a single motor as an intelligent agent, regards the desired q-axis current as a speed tracking consistency protocol, and the intelligent agent calculates and updates its own desired q-axis current according to the acquired speed information of the neighboring intelligent agent, thereby achieving speed tracking consistency based on local speed information. Compared with the traditional multi-motor speed collaborative control, the present invention uses the speed tracking consistency protocol to simultaneously realize speed tracking control and synchronization control, and does not need to design a speed tracking controller separately, thereby avoiding the mutual restraint of speed tracking performance and synchronization performance; in addition, distributed control has the advantages of simple structure, strong flexibility and high scalability. At the same time, the disturbance observer designed by the present invention has a continuous observation output value. Using such an observer to estimate and feed-forward compensate for unknown disturbances can further weaken system jitter and enhance system robustness. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 A structural diagram of the speed tracking consistency control of multiple permanent magnet synchronous motors provided in an embodiment of the present invention;

[0057] Figure 2 A directed communication topology diagram provided by an embodiment of the present invention;

[0058] Figure 3 A speed consistency effect diagram of a no-load experiment of multi-motor speed tracking and consistent control provided by an embodiment of the present invention;

[0059] Figure 4 A tracking error curve diagram of a no-load experiment of multi-motor speed tracking consistency control provided by an embodiment of the present invention;

[0060] Figure 5 A speed consistency effect diagram of a multi-motor speed tracking consistent control loading experiment provided by an embodiment of the present invention;

[0061] Figure 6 A tracking error curve diagram of a multi-motor speed tracking consistent control loading experiment provided by an embodiment of the present invention;

[0062] Figure 7 A synchronization error curve diagram of a multi-motor speed tracking consistent control loading experiment provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0064] The speed tracking consistency control method of multiple permanent magnet synchronous motors based on local information interaction proposed in this embodiment has a control structure as follows: Figure 1 As shown, the method of this embodiment is specifically described as follows.

[0065] Step 1: Design a virtual leader and describe its mathematical model as:

[0066]

[0067] Among them, ω m,0 is the virtual mechanical angular velocity, i q,0 is the virtual q-axis current, P n , ψ and J are the number of magnetic pole pairs, permanent magnet flux and moment of inertia of the real motor respectively; d / dt represents the differential operator; definition where ω ref is the speed given signal. The virtual q-axis current is designed as:

[0068]

[0069] Among them, k p is the proportional gain, k I is the integral gain. The virtual q-axis current formula (2) uses the PI control algorithm to enable the virtual leader to quickly track the given speed ω ref .

[0070] Step 2: Design a directed communication topology.

[0071] In the multi-permanent magnet synchronous motor speed coordinated control system, the local vector control subsystems of N motors are regarded as N independent nodes and the set Node v0 represents the virtual leader. i ,v j ) represents the slave node v i To node v j There is an edge, namely node v j You can get node v i The speed information. Define scalar a ij Represents the slave node v j To node v i The connection weight of j ,v i ) exists, then a ij =1, otherwise a ij =0.

[0072] Define a directed communication topology graph in is the edge set, the adjacency matrix Represents node v i The set of neighbor nodes.

[0073] Define the Laplacian matrix When i=j, When i≠j, l ij =-a ij .

[0074] Designing a suitable communication topology is a prerequisite for achieving the consistency of speed tracking of multiple permanent magnet synchronous motors. There exists a directed spanning tree with the virtual leader node as the root node, so that global tracking consistency can be achieved.

[0075] This embodiment takes the coordinated speed control of three permanent magnet synchronous motors as an example. Figure 2 Node 0 represents the virtual leader node, which does not receive information and only sends information to node 1; node 1 represents the local vector control subsystem of the first motor, which only receives information sent by node 3 and only sends information to node 2; node 2 represents the local vector control subsystem of the second motor, which only receives information sent by node 1 and only sends information to node 3; node 3 represents the local vector control subsystem of the third motor, which only receives information sent by node 2 and only sends information to node 1. Figure 2 The designed directed communication topology can start from node 0 and traverse node 1, node 2 and node 3 in sequence, thus ensuring the graph There is a directed spanning tree with the virtual leader node as the root node.

[0076] Step 3: Design a speed tracking consistency protocol.

[0077] Consider a directed communication topology graph The vector control subsystem of a single motor is regarded as an intelligent agent, and the desired q-axis current is regarded as a speed tracking consistency protocol. Obtain the speed information of neighboring agents, and calculate and update the expected q-axis current through the tracking consistency protocol to achieve speed tracking consistency. The specific steps include:

[0078] Step 3.1: Design a tracking consistency protocol.

[0079] Considering the influence of parameter perturbation, the mathematical model of permanent magnet synchronous motor is described as:

[0080]

[0081] Among them, ω m,i is the mechanical angular velocity; i q,i is the component of the stator current on the q axis; the subscript i is the motor number, i = 1, 2, ..., N; f ω,i is the speed disturbance, including friction torque and load disturbance, fω,i =-(Bω m,i +T L,i ) / J,T L,i is the load torque, and B is the viscous friction coefficient.

[0082] The consistency error is defined as:

[0083] e i =ω m,i -ω m,0 (4)

[0084] Since the agent can only obtain the virtual mechanical angular velocity ω when the virtual leader is the agent's neighbor node m,0 , Therefore, in order to avoid the introduction of global information, the relative error is defined as:

[0085]

[0086] Based on directed communication topology graph Design speed tracking consistency protocol:

[0087]

[0088] The speed tracking consistency protocol (6) only needs to obtain the speed information of neighboring nodes when updating in each control cycle, and thus can realize the speed tracking consistency control based on local information. Among them, the positive constants ρ1, ρ2, ρ3 and ρ4 are adjustable parameters; p and q are both positive odd numbers, and p<q; is the speed disturbance f ω,i The estimated value of .

[0089] Step 3.2: Estimate the unknown speed disturbance f ω,i .

[0090] Because f ω,i contains unmeasurable parts, so the following disturbance observer is designed for f ω,i Make an estimate and feed-forward compensation:

[0091]

[0092] Among them, 0<γ<1, η>1, c3>0 are observer parameters; and is the adaptive gain; parameters κ1 and κ2 are positive constants used to adjust and Adaptive law of and A positive number represents and Defining variables where ζ ω,iis an auxiliary variable and satisfies

[0093] Step 3.3: Design the current controller;

[0094] In the dq rotating coordinate system, based on i d = 0 and considering the influence of parameter perturbation, the current state equation of the multi-permanent magnet synchronous motor system is described as:

[0095]

[0096] Among them, u q,i is the component of the stator voltage on the q axis; R, L and ψ are the stator resistance, stator inductance and permanent magnet flux, respectively; f q,i represents the current disturbance, and its expression is:

[0097]

[0098] Among them, ΔR, ΔL and Δψ represent the changes of stator resistance, stator inductance and permanent magnet flux, respectively.

[0099] Defining Current Tracking Error And design the integral sliding surface:

[0100]

[0101] Where σ is a positive constant used to adjust the current tracking error The convergence speed of

[0102] make and f q,i = 0, and substituting it into the current state equation (8), the sliding mode equivalent control law can be obtained as follows:

[0103]

[0104] The current controller output, i.e., the q-axis voltage, is designed as:

[0105]

[0106] in, is the sliding mode switching control law. Derivative the integral sliding surface formula (10) and substitute the q-axis voltage formula (12) into it to obtain:

[0107]

[0108] Furthermore, due to the current disturbance f q,i It cannot be measured, so the following current disturbance observer is designed for f q,i Make an estimate:

[0109]

[0110] Among them, the variable ζ q,i is an auxiliary variable and satisfies

[0111] Furthermore, based on the current disturbance observer (14), the sliding mode switching control law is designed as:

[0112]

[0113] Among them, the adjustable parameters 0<r<1, s>1, k1, k2 and k3 are all positive constants.

[0114] The no-load speed regulation experimental results of the multi-permanent magnet synchronous motor speed tracking consistent control method based on the method of this embodiment are as follows: Figure 3 and Figure 4 As shown in Figure 1. The speed setting is set as a step signal. Figure 3 Under the control of the method proposed in this embodiment, the speed of the permanent magnet synchronous motor can quickly and smoothly converge to the given value to achieve speed tracking consistency. The transient adjustment time is about 2s, and the steady-state speed jitter is within 1r / min. The speed tracking error is defined as the difference between the speed setting and the actual output speed of the motor. According to Figure 4 , the tracking errors of all motors can converge to zero, that is, the multi-agent system achieves consistency.

[0115] The experimental results of the load disturbance resistance of the multi-permanent magnet synchronous motor speed tracking consistent control method based on the method of this embodiment are as follows: Figure 5 , Figure 6 and Figure 7 As shown. Set the speed setting value to 200r / min. After stable operation, PMSM1 suddenly adds 70% of the rated load at 30-35 seconds and 38% of the rated load at 40-60 seconds; PMSM2 suddenly adds 75% of the rated load at 50-55 seconds and 42% of the rated load at 60-65 seconds; PMSM3 suddenly adds 33% of the rated load at 60-65 seconds. Figure 5 , when a load disturbance occurs, the speed of the permanent magnet synchronous motor can quickly recover to a stable state, and the average speed recovery time is about 1.5s. Figure 6 and Figure 7 , the speed tracking error and synchronization error can continue to converge to zero after the disturbance occurs, which verifies that the multi-agent system is robust to external disturbances.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. A method for speed tracking consistency control of multiple permanent magnet synchronous motors with local information interaction, characterized in that: The method regards the vector control subsystem of a single motor in the multi-permanent magnet synchronous motor speed cooperative control system as an intelligent agent, and the intelligent agent exchanges speed information with its neighboring intelligent agents according to the designed communication topology, and updates the expected q-axis current in real time through the speed tracking consistency protocol; specifically, the method includes the following steps: Step 1: Design a virtual leader and describe its mathematical model as: Among them, ω m,0 is the virtual mechanical angular velocity, i q,0 is the virtual q-axis current, P n , ψ and J are the number of magnetic pole pairs, permanent magnet flux and moment of inertia of the real motor respectively; d / dt represents the differential operator; definition where ω ref is the speed given signal; the virtual q-axis current is designed as: Among them, k p is the proportional gain, k I is the integral gain; Step 2: Design a directed communication topology; In the multi-PMSM speed cooperative control system, the local vector control subsystems of N motors are regarded as N independent nodes and the set Indicates; node v0 represents the virtual leader; (v i ,v j ) represents the slave node v i To node v j There is an edge, namely node v j Can get node v i Speed ​​information; define scalar a ij Represents the slave node v j To node v i The connection weight of j ,v i ) exists, then a ij =1, otherwise a ij =0; Define a directed communication topology graph in is the edge set, the adjacency matrix Represents node v i The set of neighbor nodes of Define the Laplacian matrix When i=j, When i≠j, l ij =-a ij ; Step 3: Design a speed tracking consistency protocol; Consider a directed communication topology graph The vector control subsystem of a single motor is regarded as an intelligent agent, and the desired q-axis current is regarded as a speed tracking consistency protocol; the intelligent agent calculates and updates its own desired q-axis current according to the speed information obtained from neighboring intelligent agents, thereby achieving speed tracking consistency.

2. The speed tracking consistency control method of multiple permanent magnet synchronous motors with local information interaction according to claim 1 is characterized in that: The step 3 specifically comprises the following steps: Step 3.1: Design a tracking consistency protocol; Considering the influence of parameter perturbation, the mathematical model of permanent magnet synchronous motor is described as: Among them, ω m,i is the mechanical angular velocity; i q,i is the component of the stator current on the q axis; the subscript i is the motor number, i = 1, 2, ..., N; f ω,i is the speed disturbance, including friction torque and load disturbance, f ω ,i=-(Bωm,i+T L ,i) / J,T L,i is the load torque, B is the viscous friction coefficient; The consistency error is defined as: e i =ω m,i -oh m,0 (4) Define relative error: Based on directed communication topology graph Design speed tracking consistency protocol: Among them, positive constants ρ1, ρ2, ρ3 and ρ4 are adjustable parameters; p and q are both positive odd numbers, and p<q; is the speed disturbance f ω,i An estimated value of Step 3.2: Estimate the unknown speed disturbance f ω,i ; Design the disturbance observer shown in equation (7) to f ω,i Make an estimate and feed-forward compensation: Among them, 0<γ<1, η>1, c3>0 are observer parameters; and is the adaptive gain; parameters κ1 and κ2 are positive constants used to adjust and Adaptive law of and is a positive number, representing and Reference value of; define variable ζ ω,i is an auxiliary variable and satisfies Step 3.3: Design the current controller; In the dq rotating coordinate system, based on i d = 0 and considering the influence of parameter perturbation, the current state equation of the multi-permanent magnet synchronous motor system is described as: Among them, u q,i is the component of the stator voltage on the q axis; R and L are the stator resistance and stator inductance respectively; f q,i represents the current disturbance, and its expression is: Among them, ΔR, L and Δψ represent the change of stator resistance, stator inductance and permanent magnet flux linkage respectively; The current tracking error is defined as And design the integral sliding surface: Where σ is a positive constant used to adjust the current tracking error The convergence speed of make and f q,i =0, and substitute it into the current state equation (8) to obtain the sliding mode equivalent control law: The current controller output, i.e., the q-axis voltage, is designed as: in, is the sliding mode switching control law; the integral sliding mode surface formula (10) is derived, and the q-axis voltage formula (12) is substituted into it to obtain: The current disturbance observer shown in formula (14) is designed to observe the current disturbance f q,i Make an estimate: in, is the current disturbance f q,i Estimated value of; variable ζ q,i is an auxiliary variable and satisfies Based on the current disturbance observer (14), the sliding mode switching control law is designed as: Among them, the adjustable parameters 0<r<1, s>1, k1, k2 and k3 are all positive constants.

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