A model-free adaptive control method for permanent magnet linear synchronous motor

Abstract

The application relates to a model-free adaptive control method of a permanent magnet linear synchronous motor, which comprises the following steps: measuring three-phase currents and voltages of the permanent magnet linear synchronous motor, and then obtaining equivalent currents and voltages in an alpha-beta coordinate system; calculating thrust and flux linkage of the permanent magnet linear synchronous motor by using the equivalent currents and voltages in the alpha-beta coordinate system; constructing a high-order model-free adaptive speed controller and calculating a thrust difference value and a flux linkage difference value; inputting the thrust difference value and the flux linkage difference value into a flux linkage-thrust model-free adaptive controller to obtain d-q axis voltages, transforming the d-q axis voltages into voltages in the alpha-beta coordinate system, and finally generating SVPWM signals by using the voltages to control an inverter to generate three-phase voltages for driving the permanent magnet linear synchronous motor to run. The application is a high-order model-free adaptive control method, belongs to a data-driven control method, and optimizes the defects of slow convergence speed and low error precision of a traditional PI controller, and improves the control precision of the permanent magnet linear synchronous motor.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, specifically to a model-free adaptive control method for a permanent magnet linear synchronous motor. Background Technology

[0002] With the increasing mutual promotion and interdependence between cities and towns in my country, and the rapid expansion of urban core areas, it is becoming increasingly important to strengthen the rapid, safe, and comfortable transportation interconnection between different regions, thus placing higher demands on my country's rail transit industry.

[0003] Traditional rail transit systems still use rotating electric motors as traction devices. However, these motors cannot meet the requirements of complex routes and long distances in rail transit. Furthermore, rotating electric motor traction relies on the physical adhesion between the wheel and rail, which limits vehicle speed, acceleration, and climbing performance. Permanent magnet linear synchronous motors (PMLSMs) have gained widespread attention and application in rail transit due to their advantages such as high power density, high thrust, high dynamic characteristics, and high acceleration. Currently, PMLSMs in rail transit mostly employ direct thrust control, which is closed-loop control, typically using a PI controller for regulation. However, in complex operating conditions, parameter readjustment is necessary. Moreover, most modern control theories are based on ideal mathematical models, which can fluctuate when parameters change over time, leading to instability in the control system.

[0004] Chinese invention patent CN201810729163.1 discloses a discrete-time terminal sliding mode control based on equivalent control for permanent magnet linear synchronous motors, and designs a disturbance compensation system to improve anti-interference capabilities. The controller disclosed in this invention is based on a mathematical model of the linear motor and incorporates disturbance compensation to suppress nonlinear disturbances such as load disturbances. However, during actual motor operation, the motor's mathematical model changes with temperature and environmental variations, leading to inaccurate motor parameters used in the controller design. Furthermore, the designed disturbance compensation strategy increases the complexity of the algorithm and hardware implementation. Summary of the Invention

[0005] To address the aforementioned deficiencies in existing technologies, this invention proposes a model-free adaptive control method for permanent magnet linear synchronous motors. The aim is to mitigate the technical problem of instability in the direct thrust control system of permanent magnet linear synchronous motors, which is susceptible to nonlinear disturbances such as end effects, time-varying parameters, and load disturbances.

[0006] The technical solution of the invention is as follows:

[0007] A model-free adaptive control method for a permanent magnet linear synchronous motor includes the following steps.

[0008] S1: Measuring the three-phase current i of the permanent magnet linear synchronous motor a i b i c Three-phase voltage u a u b u c Perform a Clark transformation to obtain the equivalent current i in the α-β coordinate system. α i β and equivalent voltage u α u β ;

[0009] S2: Utilizing the equivalent current i in the α-β coordinate system α i β and equivalent voltage u α u β Calculate the thrust fe and flux linkage ψ of a permanent magnet linear synchronous motor. s ;

[0010] S3: Construct a high-order model-free adaptive velocity controller, which will then control the thrust reference value fe. * The thrust difference Δfe is obtained by subtracting the thrust fe from the thrust in step S2, and the given flux linkage ψ is then used. s * The magnetic flux linkage ψ calculated in step S2 s The difference is obtained by subtracting the magnetic flux difference Δψ s ;

[0011] S4: Combine the thrust difference Δfe and flux difference Δψ from step S3. s The input to the flux-thrust MIMO model-free adaptive controller is used to calculate the dq-axis voltage u. d u q , will u d u q The voltage u′ in the α-β coordinate system is obtained through IPARK transformation. α 、u′ β Using the voltage u′ in the α-β coordinate system α 、u′ β The generated SVPWM signal controls the inverter to produce a three-phase voltage to drive the permanent magnet synchronous linear motor.

[0012] Furthermore, the construction steps of the high-order model-free adaptive speed controller described in step S3 are as follows:

[0013] S301: Constructing the velocity loop of a discrete system for direct thrust control of a permanent magnet linear synchronous motor

[0014] v(k+1)=f(v(k),...,v(k-σ v),fe(k),...,fe(k-σ fe ))

[0015] Where v(k+1) is the motor speed at time k+1, and fe(k) is the motor thrust at time k, where σ v , σ fe The values ​​of the system inputs and outputs at any given time are positive integers.

[0016] S302: Establishing a high-order compact scheme dynamic linearized data model for the speed loop of a permanent magnet synchronous linear motor direct thrust control system.

[0017]

[0018] Where Δv(k+1)=v(k+1)-v(k) is the change in output speed of the permanent magnet linear synchronous motor from time k to time k+1; Δfe(k)=fe(k)-fe(k-1) is the change in thrust of the permanent magnet linear synchronous motor from time k-1 to time k. For the pseudo-partial derivative of the speed loop of the direct thrust control system for permanent magnet linear synchronous motor;

[0019] S303: The constructed high-order model-free adaptive velocity controller is...

[0020] The control law for the velocity loop of the direct thrust control system is:

[0021]

[0022] Where λ is the weighting factor in the control law, and ρ1 and ρ2 are the step size factors in the control law.

[0023] The pseudo-partial derivative estimation law of the control law summary is as follows:

[0024]

[0025]

[0026] Where μ1 and μ2 are the weighting factors of the partial derivative estimation law, η1, η2, η3, and η4 are the step size factors of the partial derivative estimation law, m is the order of the partial derivative, and α and β are the weighting coefficients of the partial derivative.

[0027] Furthermore, σ v , σ fe It equals 1.

[0028] Furthermore, in step S3, the high-order model-free adaptive velocity controller calculates the thrust reference value fe. * The method is to use the given input velocity v *The velocity difference Δv is obtained by subtracting the velocity v collected by the motor. The velocity difference Δv is then input into a high-order model-free adaptive speed controller to obtain the thrust reference value fe. * .

[0029] Furthermore, the construction steps for the flux-thrust MIMO model-free adaptive controller in step S4 are as follows:

[0030] S401: Constructing a Discrete System for Direct Thrust Control of a Permanent Magnet Linear Synchronous Motor

[0031] y(k+1)=f(y(k),...,y(k-σ y ),u(k),...,u(k-σ u ))

[0032] in, y(k+1) represents the motor flux linkage and thrust at time k+1, and u(k) represents the motor dq-axis voltage control input at time k, where σ y , σ u The values ​​of the system inputs and outputs at any given time are positive integers.

[0033] S402: Establishing a compact-format dynamic linearized data model for a model-free adaptive controller of a permanent magnet synchronous linear motor with flux linkage-thrust MIMO direct thrust control.

[0034]

[0035] in, Let be the pseudo-partial derivative matrix of the flux linkage-thrust loop in the direct thrust control system of the permanent magnet linear synchronous motor. Δy(k+1)=y(k+1)-y(k) is the flux linkage-thrust change of the permanent magnet linear synchronous motor from time k to time k+1, and Δu(k)=u(k)-u(k-1) is the dq axis voltage control input change of the permanent magnet linear synchronous motor from time k-1 to time k.

[0036] S403: The constructed flux linkage-thrust ring MIMO model-free adaptive controller is...

[0037] Among them, the control law of the flux linkage-thrust ring in the direct thrust control system of the permanent magnet linear synchronous motor is:

[0038]

[0039] Where λ is the weighting factor in the control law, and ρ is the step size factor in the control law.

[0040] The law for estimating partial derivatives is:

[0041]

[0042] Where μ is the weighting factor of the partial derivative estimation law, and η is the step size factor of the partial derivative estimation law.

[0043] Furthermore, σ y , σ u It equals 1.

[0044] Furthermore, in step S1, the equivalent current i in the α-β coordinate system is used. α i β and equivalent voltage u α u β Calculate the thrust fe and flux linkage ψ of a permanent magnet linear synchronous motor. s The method is

[0045]

[0046]

[0047] Compared with the prior art, the present invention has the following advantages:

[0048] 1. The model-free adaptive control method for permanent magnet linear synchronous motors proposed in this invention is a high-order model-free adaptive control method, belonging to a data-driven control method. It optimizes the shortcomings of traditional PI controllers, such as slow convergence speed and low error accuracy, and improves the control accuracy of permanent magnet linear synchronous motors.

[0049] 2. The permanent magnet linear synchronous motor model-free adaptive control method proposed in this invention, wherein the flux-thrust MIMO model-free adaptive controller merges two PI controllers, the flux loop and the thrust loop, into a single flux-thrust MIMO model-free adaptive controller to further improve the control performance of the direct thrust control system. Attached Figure Description

[0050] Figure 1 This is a flowchart of the model-free adaptive control method for permanent magnet linear synchronous motors according to the present invention;

[0051] Figure 2 A block diagram illustrating the principle of a model-free adaptive control method for permanent magnet linear synchronous motors;

[0052] Figure 3 The internal logic block diagram of the model-free adaptive speed control and flux-thrust MIMO model-free adaptive controller is shown.

[0053] Figure 4 The velocity curve is based on model-free adaptive control under load disturbance. Detailed Implementation

[0054] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0055] Figures 1 to 3 The model-free adaptive control method for a permanent magnet linear synchronous motor, as shown, includes the following steps:

[0056] S1: Measuring the three-phase current i of the permanent magnet linear synchronous motor a i b i c Three-phase voltage u a u b u c Perform a Clark transformation to obtain the equivalent current i in the α-β coordinate system. α i β and equivalent voltage u α u β .

[0057] S2: Utilizing the equivalent current i in the α-β coordinate system α i β and equivalent voltage u α u β Calculate the thrust fe and flux linkage ψ of a permanent magnet linear synchronous motor. s The specific calculation process is as follows.

[0058]

[0059]

[0060] Where p n Let τ be the number of pole pairs of the motor, and τ be the pole pitch of the motor.

[0061] S3: Construct a high-order model-free adaptive velocity controller to calculate the thrust reference value fe. * The thrust difference Δfe is obtained by subtracting the calculated thrust fe from the given flux linkage ψ. s * The magnetic flux linkage ψ calculated in step S2 s The difference is obtained by subtracting the magnetic flux difference Δψ s The specific method for constructing a high-order model-free adaptive velocity controller is as follows.

[0062] S301: Constructing the velocity loop of a discrete system for direct thrust control of a permanent magnet linear synchronous motor

[0063] v(k+1)=f(v(k),...,v(k-σ v ),fe(k),...,fe(k-σ fe ))

[0064] Where v(k+1) is the motor speed at time k+1, and fe(k) is the motor thrust at time k, where σ v , σ feThis represents the value of the system input and output at any given time, and is a positive integer, taking the value σ. v , σ fe It equals 1.

[0065] S302: Establishing a high-order compact scheme dynamic linearized data model for the speed loop of a permanent magnet synchronous linear motor direct thrust control system.

[0066]

[0067] Where Δv(k+1)=v(k+1)-v(k) is the change in output speed of the permanent magnet linear synchronous motor from time k to time k+1; Δfe(k)=fe(k)-fe(k-1) is the change in thrust of the permanent magnet linear synchronous motor from time k-1 to time k. This is the pseudo-partial derivative of the speed loop in the direct thrust control system of a permanent magnet linear synchronous motor.

[0068] S303: The constructed high-order model-free adaptive velocity controller is...

[0069] The control law for the velocity loop of the direct thrust control system is:

[0070]

[0071] Where λ is the weighting factor in the control law, and ρ1 and ρ2 are the step size factors in the control law.

[0072] The pseudo-partial derivative estimation law of the control law summary is as follows:

[0073]

[0074]

[0075] Where μ1 and μ2 are the weighting factors of the partial derivative estimation law, η1, η2, η3, and η4 are the step size factors of the partial derivative estimation law, m is the order of the partial derivative, and α and β are the weighting coefficients of the partial derivative.

[0076] After constructing the high-order model-free adaptive velocity controller, the thrust reference value fe can be calculated using this velocity controller. * Specifically, given the input velocity v * The speed difference Δv is obtained by subtracting the speed v collected by the motor and inputting the speed difference Δv into the system. Figure 2 The thrust reference value fe is obtained from the high-order model-free adaptive velocity controller HMFAC shown. * .

[0077] S4: Combine the thrust difference Δfe and flux difference Δψ from step S3. sThe input to the flux-thrust MIMO model-free adaptive controller is used to calculate the dq-axis voltage u. d u q , will u d u q The voltage u′ in the α-β coordinate system is obtained through IPARK transformation. α 、u′ β Using the voltage u′ in the α-β coordinate system α 、u′ β The generated SVPWM signal controls the inverter to produce a three-phase voltage to drive the permanent magnet synchronous linear motor.

[0078] The construction steps for the flux-thrust MIMO model-free adaptive controller in step S4 are as follows:

[0079] S401: Constructing a Discrete System for Direct Thrust Control of a Permanent Magnet Linear Synchronous Motor

[0080] y(k+1)=f(y(k),...,y(k-σ y ),u(k),...,u(k-σ u ))

[0081] in, y(k+1) represents the motor flux linkage and thrust at time k+1, and u(k) represents the motor dq-axis voltage control input at time k, where σ y , σ u This represents the value of the system input and output at any given time, and is a positive integer, taking the value σ. y , σ u It equals 1.

[0082] S402: Establish a tight-format dynamic linearized data model for direct thrust control flux-thrust loop MIMO of permanent magnet synchronous linear motor.

[0083] To ensure the rigor of the data model, the following assumptions are made regarding the direct thrust control system of the permanent magnet linear motor:

[0084] Assumption 1: Except at finite moments, the partial derivatives of f(...) in steps S301 and 401 with respect to the control input signal u(k) exist and are continuous.

[0085] Assumption 2: The direct thrust control system of the permanent magnet linear synchronous motor is Lipschitz, that is, it satisfies the following for any time k and ||u(k)||≠0:

[0086] |Δy(k+1)|≤b|Δu(k)|

[0087] Assumption 3: For a given permanent magnet linear synchronous motor in a direct thrust control system, the expected value y *For (k+1), there always exists a bounded u(k) such that, under the control input u(k) at the current moment, the output of the permanent magnet linear synchronous motor control system is equal to y. * (k+1).

[0088] For a direct thrust control system of a permanent magnet linear synchronous motor, when the above three assumptions are satisfied, a pseudo-partial derivative must exist when |Δu(k)|≠0. Make

[0089]

[0090] In the above formula, Let be the pseudo-partial derivative matrix of the flux linkage-thrust loop in the direct thrust control system of the permanent magnet linear synchronous motor. Δy(k+1)=y(k+1)-y(k) is the flux linkage-thrust change of the permanent magnet linear synchronous motor from time k to time k+1. Δu(k)=u(k)-u(k-1) is the dq axis voltage control input change of the permanent magnet linear synchronous motor from time k-1 to time k. b is a positive constant.

[0091] S403: The constructed flux-thrust ring MIMO model-free adaptive controller is as follows.

[0092] Design a flux-thrust loop control law for direct thrust control of a permanent magnet linear synchronous motor, considering the following criterion function:

[0093] J(u(k))=||y * (k+1)-y(k+1)|| 2 +λ||u(k)-u(k-1)|| 2

[0094] Differentiating u(k) with respect to zero, we obtain the flux linkage-thrust loop control law for direct thrust control of the permanent magnet linear synchronous motor:

[0095]

[0096] Where λ is the weighting factor in the control law, and ρ is the step size factor in the control law.

[0097] Consider the following pseudo-partial derivative estimation criterion function:

[0098]

[0099] in For the pseudo-partial derivative estimation matrix, By taking the derivative and setting it equal to zero, we can obtain an algorithm for estimating the pseudo-partial derivative:

[0100] The law for estimating partial derivatives is, Where μ is the weighting factor of the partial derivative estimation law, and η is the step size factor of the partial derivative estimation law.

[0101] In step S301, the equation v(k+1)=f(v(k),...,v(k-σ) v ),fe(k),...,fe(k-σ fe The equation y(k+1)=f(y(k),...,y(k-σ) in step S401 is... y ),u(k),...,u(k-σ u In the equation, f(...) is a general nonlinear function, which can be determined as follows.

[0102] The model-free adaptive control method for permanent magnet linear synchronous motors designed in this invention can improve the disturbance rejection capability, speed tracking performance, and system robustness of permanent magnet linear synchronous motors, thereby reducing nonlinear disturbances during motor operation. See details... Figure 4 The speed curve based on the model-free adaptive control algorithm under load disturbance is shown. As can be seen from the curve, after the permanent magnet linear synchronous motor starts under load, it converges to the desired speed with only a small overshoot. Moreover, when a sudden load disturbance is applied during operation, the model-free adaptive control algorithm exhibits strong robustness; the speed curve only experiences a small overshoot and then quickly converges to the desired speed curve within 0.01 seconds.

Claims

1. A model-free adaptive control method for a permanent magnet linear synchronous motor, comprising the following steps: S1: Measuring the three-phase current of a permanent magnet linear synchronous motor , , Three-phase voltage , , Perform a Clark transformation to obtain Equivalent current in coordinate system , and equivalent voltage , ; S2: Utilize Equivalent current in coordinate system , and equivalent voltage , Calculate the thrust of a permanent magnet linear synchronous motor Magnetic Link ; S3: Construct a high-order model-free adaptive velocity controller, and calculate the thrust reference value using the high-order model-free adaptive velocity controller. With thrust thrust difference , give a magnetic flux The magnetic flux calculated in step S2 The difference is obtained by subtracting the magnetic flux difference. ; S4: Calculate the thrust difference from step S3. Difference with magnetic flux The input is fed into the flux-thrust MIMO model-free adaptive controller for calculation. shaft voltage , ,Will , After IPARK transformation, it becomes Voltage in coordinate system , ,use Voltage in coordinate system , The generated SVPWM signal controls the inverter to produce a three-phase voltage to drive the permanent magnet synchronous linear motor. The construction steps of the model-free adaptive controller for flux linkage-thrust MIMO are as follows: S401: Constructing a Discrete System for Direct Thrust Control of a Permanent Magnet Linear Synchronous Motor ; in, , , for The motor flux and thrust at any given moment, for Time Motor Shaft voltage control input, where , The values ​​of the system inputs and outputs at any given time are positive integers. S402: Establishing a compact-format dynamic linearized data model for direct thrust control flux-thrust loop MIMO of a permanent magnet synchronous linear motor: ; in, This represents the pseudo-partial derivative matrix of the flux linkage-thrust loop in the direct thrust control system of a permanent magnet linear synchronous motor. for Time's up The flux linkage-thrust change of a permanent magnet linear synchronous motor at all times. for Time's up Permanent magnet linear synchronous motor Shaft voltage control input variation; S403: The constructed model-free adaptive controller for flux linkage-thrust loop MIMO is as follows: The control law for the flux linkage-thrust loop in the direct thrust control system of the permanent magnet linear synchronous motor is as follows: ; in, These are the weighting factors in the control law. This is the step size factor in the control law; The law for estimating partial derivatives is, ; in The weighting factor for the partial derivative estimation law, is the step size factor of the partial derivative estimation law.

2. The model-free adaptive control method for permanent magnet linear synchronous motors as described in claim 1, characterized in that, The construction steps of the high-order model-free adaptive velocity controller mentioned in step S3 are as follows: S301: Constructing the velocity loop of a discrete system for direct thrust control of a permanent magnet linear synchronous motor: ； in, for The motor speed at any given time, for The thrust of the motor at all times, of which , The values ​​of the system inputs and outputs at any given time are positive integers. S302: Establishing a high-order compact scheme dynamic linearized data model for the speed loop of a permanent magnet synchronous linear motor under direct thrust control: ; in, for Time's up The change in output speed of the permanent magnet linear synchronous motor at any given time; for Time's up The change in thrust of the permanent magnet linear synchronous motor at any given time; , For the pseudo-partial derivative of the speed loop of the direct thrust control system for permanent magnet linear synchronous motor; S303: The constructed high-order model-free adaptive velocity controller is as follows: The control law for the velocity loop of the direct thrust control system is as follows: ； in, These are the weighting factors in the control law. , This is the step size factor in the control law; The pseudo-partial derivative estimation law for the sum of control laws is: ； ； in, , The weighting factor for the partial derivative estimation law, , , , The step size factor is the partial derivative estimation law. Let be the order of the partial derivative. , These are the weighting coefficients for the partial derivatives.

3. The model-free adaptive control method for permanent magnet linear synchronous motors as described in claim 2, characterized in that: The , It equals 1.

4. The model-free adaptive control method for permanent magnet linear synchronous motors as described in claim 1, characterized in that, The high-order model-free adaptive velocity controller described in step S3 calculates the thrust reference value. The method is as follows: based on the given input speed and the speed collected by the motor The difference in velocity is obtained by subtraction. , speed difference The thrust reference value is obtained by inputting it into a high-order model-free adaptive velocity controller. .

5. The model-free adaptive control method for permanent magnet linear synchronous motors as described in claim 1, characterized in that: The , It equals 1.

6. The model-free adaptive control method for permanent magnet linear synchronous motors as described in claim 1, characterized in that: In step S2, utilize Equivalent current in coordinate system , and equivalent voltage , Calculate the thrust of a permanent magnet linear synchronous motor Magnetic Link The method is as follows: ； ； in, This represents the number of pole pairs of the motor. This represents the pole pitch of the motor.

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