Disturbance suppression compensation method for linear oscillation motor control

Abstract

The invention provides a disturbance suppression compensation method for linear oscillation motor control, and belongs to the field of linear oscillation motor sensorless control, and the method comprises the steps: constructing a position controller and a disturbance observer according to a kinematics equation of a linear oscillation motor, a superhelix algorithm and a generalized superhelix algorithm; taking a difference between a given rotor position signal and an estimated rotor position signal as an error of a sliding mode surface, and combining an exponential approach rate and a constant-speed approach rate to be applied to the sliding mode surface, so that the sliding mode surface can reach a balance position more quickly; constructing a position controller according to a superhelix algorithm, and outputting a control current signal; a control current signal and a speed error signal of a rotor are used as input of a generalized super-spiral disturbance observer, a disturbance signal of a motor system is estimated under the action of the observer, and a compensation current is input to a motor, so that the influence of disturbance is reduced; a sliding mode observer is used for collecting current and voltage signals from a linear oscillation motor, estimating a position signal and a speed signal of a rotor according to the current and voltage signals, and inputting the position signal and the speed signal into a position controller and a disturbance observer. According to the method, the sensorless control capability of the linear oscillation motor can be enhanced, and the influence of disturbance can be effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of position sensorless control of linear oscillation motors, and more specifically, relates to a disturbance suppression and compensation method for controlling a linear oscillation motor. Background Art

[0002] Traditional compressors are driven by rotary motors, and the motion mode is converted from rotary to reciprocating linear motion through a crank-connecting rod mechanism to perform refrigeration work. However, this motion conversion method results in low compressor efficiency, high noise during operation, and large radial force and friction during the motion process. As the working time goes by, it will cause greater wear and tear, resulting in deterioration of refrigeration performance. With the emergence of linear compressors, linear motors are used instead of rotary motors. Since there is no need for motion conversion, the refrigeration efficiency is greatly improved, and since there is no radial force, the noise during the operation of the linear compressor is reduced; due to structural changes, the volume of the compressor is also greatly reduced. Since the linear compressor driven by a linear oscillation motor has no connection with a connecting rod, the displacement of the linear compressor piston is not limited. Once the clearance is very small, if the piston displacement is not limited, it is very easy for the piston to hit the cylinder, causing structural damage to the linear compressor. The application of position sensors can effectively detect the piston position, but the sensor is expensive and difficult to install. Especially after the linear compressor is packaged in the shell, it is easily affected by electromagnetics, thereby affecting the normal operation of the linear compressor. The application of a position sensorless control method can solve the above problems. However, since the linear oscillation motor is essentially a nonlinear system, there are complex interferences from the system's internal or external environment, which have a negative impact on the control of the motor system. Therefore, adding a disturbance observer when controlling the linear oscillation motor without a position sensor can estimate the disturbance and suppress it, which is an effective way to solve the above problem. Summary of the invention

[0003] In view of the defects of the prior art, the purpose of the present invention is to provide a disturbance suppression and compensation method for linear oscillation motor control, aiming to solve the problem that the existing linear oscillation motor is easily affected by disturbances and has reduced reliability when controlled without a position sensor.

[0004] To achieve the above object, on the one hand, the present invention provides a linear oscillation motor control disturbance suppression compensation method, comprising the following steps:

[0005] S1: Transform the kinematic equation of the linear oscillation motor to obtain the state equation of the motor system;

[0006] S2: Based on the state equation of the motor system, the sliding surface is designed, the exponential approach rate and the constant velocity approach rate are introduced, and the position controller is constructed by combining the super helical algorithm;

[0007] S3: Collect the voltage and current signals of the linear oscillation motor, and output the observed speed signal and position signal by the sliding mode observer using the back electromotive force method, and input them into the position controller and the generalized super-helical disturbance observer;

[0008] S4: The error between the observed speed signal and the given speed signal, as well as the control current output by the position controller enter the generalized super-helical disturbance observer, and the disturbance or load existing in the current motor system is estimated, and the compensation current is output, and then go to step S1.

[0009] Preferably, step S1 specifically includes the following steps: According to the kinematic equation of the linear oscillation motor: (1), the system state equation of the motor is obtained by transformation: (2), where m is the mass of the mover, C For damping, K is the spring stiffness coefficient, F e is the electromagnetic thrust, F f is the friction force, F g is the gas force, K e is the electromagnetic thrust coefficient, X ( t )Motor displacement, x 3 is the combined force of spring force, gas force and friction force and the mass of the mover m The ratio of ρ is its derivative.

[0010] Preferably, step S2 specifically includes the following steps: The sliding surface is: (3), after taking the derivative, we get: (4)

[0011] The approach rate is: (5), combining the state equation, sliding surface and approach rate of the motor system, the control input current of the position controller can be obtained: (6), Based on this, the position controller can be obtained: (7).

[0012] in e = x d - x is the tracking error of the system, x d is the given position signal,h is a constant (set as needed), k 1 , k 2 Design parameters for the superhelix algorithm (set as needed); U is the control input; s is the sliding surface.

[0013] Preferably, step S3 specifically includes the following steps: According to the voltage equation of the linear oscillation motor: (8)

[0014] The back electromotive force method is derived, and the displacement calculation formula of the mover is: (9), the speed and position signals of the actuator can be estimated using the sliding mode observation method according to the formula.

[0015] Among them, when the linear oscillation motor is working, the induced electromotive force generated e The speed of the mover v Directly proportional. R is the equivalent resistance of the system, U ( t ) is the equivalent voltage, L For inductance.

[0016] Preferably, step S4 specifically includes the following steps:

[0017] S4.1: Based on the nonlinear state equation of the linear oscillation motor, construct the extended state equation;

[0018] S4.2: The estimated speed signal is compared with the given speed signal to obtain the speed error, and a generalized superhelical disturbance observer is established. The compensation current is output by the generalized superhelical disturbance observer and input into the motor system.

[0019] Preferably, based on the system state equation of the linear oscillation motor, an extended state equation is constructed, and a generalized superhelical disturbance observer is established to obtain the error state equation of the system, which can be brought back to the extended state equation to obtain the compensation current.

[0020] Preferably, the extended state equation is: (10).

[0021] in yes x 2 , x 3 The estimated value of x 2 is the speed of the mover, x 3 is the ratio of the system disturbance to the mass of the mover, ρ is the derivative of the sum of the perturbations in the system, satisfying | ρ |≤ δ , δ >0, K e is the electromagnetic thrust coefficient of the linear oscillation motor, m is the mass of the mover, i r It is the linear oscillation motor control input current.

[0022] Preferably, the generalized superhelical disturbance observer is: (11)

[0023] in yes x 2 , x 3 The estimated value of x 3 is the ratio of the system disturbance to the mass of the mover, and is defined as , l 1 , l 2 , l 3 , l 4 is the positive gain coefficient of the controller (set as needed).

[0024] Preferably, the error equation of the generalized superhelical disturbance observer is: (12).

[0025] Preferably, the compensation current is: The control current output by the position controller and the compensation current output by the disturbance observer work together to form a position sensorless control system for the linear oscillation motor.

[0026] On the other hand, the present invention provides a linear oscillation motor control disturbance suppression compensation method, including constructing: a position loop controller, a generalized super-helical disturbance observer, a PI current controller, an SPWM inverter and a sliding mode observer.

[0027] The position loop controller is used to collect the mover position signal of the linear oscillation motor estimated by the sliding mode observer and output the control current.

[0028] The generalized superhelical disturbance observer is used to collect the mover velocity signal estimated by the sliding mode observer and compare it with the given velocity signal. Under the action of the disturbance observer, the disturbance signal acting on the linear oscillation motor is estimated and the compensation current is output.

[0029] The PI current controller is used to perform PI control operation based on the difference between the current input current and the output current of the motor system.

[0030] The SPWM inverter is used to receive the rectangular wave and the fundamental frequency component, and adjust the frequency and amplitude of the modulation voltage signal, thereby modulating the motor.

[0031] The sliding mode observer is used to collect the voltage and current signals from the linear oscillation motor, and estimate and output the current mover speed and displacement based on the back electromotive force principle.

[0032] In general, the above technical solution conceived by the present invention has the following beneficial effects compared with the prior art.

[0033] The generalized superhelical algorithm adopted by the present invention can compensate the motor system when facing various unknown disturbances, and can improve the accuracy and tracking performance of the system.

[0034] The application basis of the present invention is the field of position sensorless control. Compared with traditional position sensorless control, the present invention takes more influence of disturbance into consideration and improves the robustness of the system.

[0035] The generalized superhelical disturbance observer adopted in the present invention is based on the application of high-order sliding modes, which can eliminate the influence of sliding mode chattering in principle. In addition, the generalized superhelical algorithm only needs to know the value of the sliding mode variable itself and does not require additional information, so it is easy to implement. Description of the drawings:

[0037] Figure 1 It is a structural block diagram of a position loop controller provided by an embodiment of the present invention.

[0038] Figure 2 It is a structural block diagram of a generalized superhelical disturbance observer provided by an embodiment of the present invention.

[0039] Figure 3 It is a block diagram of position sensorless control of a linear oscillation motor provided by an embodiment of the present invention.

[0040] Figure 4 It is a structural diagram of a linear oscillation motor provided in an embodiment of the present invention.

[0041] Figure 5 It is a mechanical schematic diagram and an equivalent circuit diagram of the linear oscillation motor provided in an embodiment of the present invention.

[0042] Figure 6 It is a position diagram of a mover controlled without a position sensor provided in an embodiment of the present invention.

[0043] Figure 7 It is a diagram of the position error of the mover when there is a disturbance and when there is and when there is no disturbance observer provided by an embodiment of the present invention. Specific implementation method:

[0045] In order to make the content, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] The present invention provides a disturbance suppression method for linear oscillation motor control, comprising:

[0047] S1: Transform the kinematic equation of the linear oscillation motor to obtain the state equation of the motor system; Figure 4 The structure of the linear oscillation motor shown can be used Figure 5 The structural diagram shown shows that the kinematic equation of the linear oscillation motor is: (13).

[0048] in m is the mass of the mover, C For damping, K is the spring stiffness coefficient, F e is the electromagnetic thrust, F f is the friction force, F g is the gas force, K e is the electromagnetic thrust coefficient, X ( t )Motor displacement.

[0049] The state equation of the linear motor system is obtained by transforming formula (13): (14).

[0050] in v is the speed of the mover, x 3 is the combined force of spring force, gas force and friction force and the mass of the mover m The ratio of ρ is its derivative.

[0051] S2: Based on the state equation of the motor system, the sliding surface is designed, the exponential approach rate and the constant velocity approach rate are introduced, and the position controller is constructed by combining the super helical algorithm;

[0052] The sliding surface is: (15), after taking the derivative, we get: (16).

[0053] in e = x d -x is the tracking error of the system, x d is the given position signal, h is a constant (set as needed).

[0054] The approach rate is: (17) in k 1 , k 2 is the design parameter (set as needed).

[0055] Substituting formula (14) (17) into (16) we can get the control input current of the position controller: (18).

[0056] Based on this, the position controller can be obtained: (19) k 1 , k 2 Design parameters for the superhelix algorithm (set as needed); U is the control input; s is the sliding surface.

[0057] S3: Collect the voltage and current signals of the linear oscillation motor, and output the observed speed signal and position signal by the sliding mode observer using the back electromotive force method, and input them into the position controller and the generalized super-helical disturbance observer;

[0058] Figure 5 The equivalent circuit diagram of the linear oscillation motor is also revealed. According to the voltage equation of the linear oscillation motor: (20).

[0059] The displacement calculation formula of the mover can be derived as follows: (twenty one).

[0060] Among them, when the linear oscillation motor is working, the induced electromotive force generated e The speed of the mover v Directly proportional. R is the equivalent resistance of the system, U ( t ) is the equivalent voltage, L is the inductance. According to the formula, the speed and position signals of the mover can be estimated by using the sliding mode observation method.

[0061] S4: The error between the observed speed signal and the given speed signal, as well as the control current output by the position controller enter the generalized super-helical disturbance observer, and the disturbance or load existing in the current motor system is estimated, and the compensation current is output, and then go to step S1.

[0062] Preferably, step S4 specifically includes the following steps:

[0063] S4.1: Based on the nonlinear state equation of the linear oscillation motor, construct the extended state equation;

[0064] S4.2: The estimated speed signal is compared with the given speed signal to obtain the speed error, and a generalized superhelical disturbance observer is established. The compensation current is output by the generalized superhelical disturbance observer and input into the motor system.

[0065] Specifically, the specific implementation method of step S4.1 is as follows:

[0066] According to the state equation (14) of the linear oscillation motor, the extended state equation can be derived: (twenty two).

[0067] in yes x 2 , x 3 The estimated value of x 2 is the speed of the mover, x 3 is the ratio of the system disturbance to the mass of the mover, ρ is the derivative of the sum of the perturbations in the system, satisfying | ρ |≤ δ , δ >0, K e is the electromagnetic thrust coefficient of the linear oscillation motor, m is the mass of the mover, i r It is the linear oscillation motor control input current.

[0068] Specifically, the specific execution process of step S4.2 is:

[0069] According to the extended state equation (22), the optical generalized superhelical disturbance observer is obtained as: (twenty three).

[0070] in yes x 2 , x 3 The estimated value of x 3is the ratio of the system disturbance to the mass of the mover, and is defined as , l 1 , l 2 , l 3 , l 4 is the positive gain coefficient of the controller (set as needed).

[0071] According to formula (23), the error equation of the disturbance observer can be obtained: (twenty four).

[0072] Substituting (24) back into the expanded state equation (22), the compensation current can be derived: (25), the control current output by the position controller and the compensation current output by the disturbance observer work together to form a position sensorless control system for the linear oscillation motor.

[0073] The structure diagram of the position controller of the control system is as follows Figure 1 As shown in Figure 1, after the super-helical algorithm is applied, the linear oscillation motor outputs a control current signal. The structure of the generalized super-helical disturbance observer is shown in Figure 1. Figure 2 As shown, when the input estimated rotor speed signal is subtracted from the given speed signal and input into the disturbance observer as the speed error, the disturbance observer can estimate the disturbance suffered by the current system according to the error size and convert it into a compensation current signal to act on the current linear oscillation motor system.

[0074] The linear oscillation motor without position sensor control block diagram constructed by the present invention is as follows: Figure 3 As shown, in the present invention, the currently estimated position signal and the given position signal pass through the position loop controller to control the position signal, and the control current is obtained. The current is limited by the PI current controller, and the sliding mode observer collects the voltage and current signals of the linear oscillation motor to estimate the speed and position information of the mover, and the estimated speed signal flows through the generalized superhelical disturbance observer to realize the control of the linear oscillation motor.

[0075] Example

[0076] The linear oscillation motor used in this embodiment has an operating voltage of 100V, an operating frequency of 50Hz, an equivalent resistance of 16.6Ω, an inductance of 0.064mH, a mover mass of 0.4kg, an electromagnetic thrust coefficient of 100, and a spring stiffness of 12000.

[0077] Specifically, Figure 6 The position of the rotor of the linear oscillation motor under this control method can be seen to meet the usage requirements. Figure 7The results of the position error of the mover when the disturbance exists and whether the generalized superhelical perturbation observer is included. (a) is the result of the position error of the mover without the generalized superhelical perturbation observer, and (b) is the result of the position error of the mover with the generalized superhelical perturbation observer. This is a 200N disturbance applied from 0.5s to 1.0s. It can be seen that when there is no generalized superhelical perturbation observer at 1.0s, the mover error suddenly changes to 4.7×10 -5 m, when there is a generalized superhelical perturbation observer, the mover error is 2.8×10 -5 m. Obviously, the proposed method can effectively reduce the influence of disturbance on the control of the linear oscillation motor, and keep the position error of the mover within a certain range. It has excellent robustness and anti-interference ability, and greatly improves the control effect of the position sensorless control of the linear oscillation motor.

[0078] In summary, the disturbance suppression and compensation method for linear oscillation motor control provided by the present invention can effectively reduce the influence of disturbance on the linear oscillation motor control, and improve the anti-interference ability and robustness of the motor system.

[0079] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A disturbance suppression method for linear oscillation motor control, characterized in that: The following steps are involved: S1: Transform the kinematic equation of the linear oscillation motor to obtain the state equation of the motor system; S2: Based on the state equation of the motor system, the sliding surface is designed, the exponential approach rate and the constant velocity approach rate are introduced, and the position controller is constructed by combining the super helical algorithm; S3: Collect the voltage and current signals of the linear oscillation motor, and output the observed speed signal and position signal by the sliding mode observer using the back electromotive force method, and input them into the position controller and the generalized super-helical disturbance observer; S4: The error between the observed speed signal and the given speed signal, as well as the control current output by the position controller enter the generalized super-helical disturbance observer, and the disturbance or load existing in the current motor system is estimated, and the compensation current is output, and then go to step S1.

2. The disturbance suppression method for linear oscillation motor control according to claim 1, characterized in that: The kinematic equation of the linear oscillation motor in step S1 is: , the system state equation of the motor is transformed into ,in m is the mass of the mover, C For damping, K is the spring stiffness coefficient, F e is the electromagnetic thrust, F f is the friction force, F g is the gas force, K e is the electromagnetic thrust coefficient, X ( t )Motor displacement, x 3 is the combined force of spring force, gas force and friction force and the mass of the mover m The ratio of ρ is its derivative.

3. The disturbance suppression method for linear oscillation motor control according to claim 1, characterized in that The position controller process constructed in step S2 is: The sliding surface is: , after taking the derivative, we get: , The approach rate is: , combined with the state equation, sliding surface and approach rate of the motor system, the control input current of the position controller can be obtained: , Based on this, the position controller can be obtained: , in e = x d - x is the tracking error of the system, x d is the given position signal, h is a constant (set as needed), k 1, k 2 is the design parameter of the superhelix algorithm (set as needed); U is the control input; s is the sliding surface.

4. The disturbance suppression method for linear oscillation motor control according to claim 1, characterized in that: The back electromotive force method of step S3 is: According to the voltage equation of the linear oscillation motor: , The back electromotive force method is derived, and the displacement calculation formula of the mover is: According to the formula, the sliding mode observation method can be used to estimate the speed and position signals of the mover. When the linear oscillation motor is working, the induced electromotive force generated e The speed of the mover v Directly proportional. R is the equivalent resistance of the system, U ( t ) is the equivalent voltage, L For inductance.

5. The disturbance suppression method for linear oscillation motor control according to claim 1, characterized in that: Step S4 specifically includes the following steps: S4.1: Based on the nonlinear state equation of the linear oscillation motor, construct the extended state equation; S4.2: The estimated speed signal is compared with the given speed signal to obtain the speed error, and a generalized superhelical disturbance observer is established. The compensation current is output by the generalized superhelical disturbance observer and input into the motor system.

6. The linear oscillation motor disturbance suppression method according to claim 1, characterized in that A generalized superhelical disturbance observer is constructed based on the generalized superhelical algorithm, and the actuator velocity and position signals are estimated through a sliding mode observer.

7. The linear oscillation motor control disturbance suppression method according to claim 5, characterized in that The extended state equation is: ,in yes x 2, x An estimated value of 3, x 2 is the speed of the mover, x 3 is the ratio of system disturbance to the mass of the mover, ρ is the derivative of the sum of the perturbations in the system, satisfying | ρ |≤ δ , δ >0, K e is the electromagnetic thrust coefficient of the linear oscillation motor, m is the mass of the mover, i r It is the linear oscillation motor control input current.

8. The linear oscillation motor control disturbance suppression method according to claim 5, characterized in that The generalized superhelical disturbance observer is: , in yes x 2, x An estimated value of 3, x 3 is the ratio of system disturbance to the mass of the mover, and is defined as , l 1, l 2, l 3. l 4 is the positive gain coefficient of the controller (set as needed).

9. The disturbance suppression method for linear oscillation motor control according to claim 5, characterized in that The error equation of the generalized superhelical disturbance observer is: .

10. The disturbance suppression method for linear oscillation motor control according to claim 5, characterized in that The compensation current is: The control current output by the position controller and the compensation current output by the disturbance observer work together to form a position sensorless control system for the linear oscillation motor.

Images