A high-speed sensorless control method in permanent magnet synchronous motor

Abstract

The application discloses a high-speed position sensorless control method for a permanent magnet synchronous motor, and relates to the technical field of motor control. The current state equation of the motor is constructed based on an extended flux model, and a rotor position estimation scheme combining an ultra-twisted sliding mode observer, a complex coefficient filter and an enhanced extended state observer is designed accordingly. The control object is an interior permanent magnet synchronous motor, and the motor control strategy adopts a double closed loop vector control of speed and current. The observation value of the differential item of the extended flux of the motor is obtained through the ultra-twisted sliding mode observer, and after the disturbance factors are preliminarily filtered out through the complex coefficient filter, the inverse tangent calculation is performed to obtain the estimated rotor position containing the disturbance. The estimated rotor position is then input into the enhanced extended state observer to obtain the accurate rotor position and speed. Compared with the traditional scheme, the application has better dynamic response, estimation accuracy and robustness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor control, in particular to a high-speed position sensorless control method in a permanent magnet synchronous motor. BACKGROUND

[0002] The permanent magnet synchronous motor is widely used in large-scale integrated circuit manufacturing, robot control, precision manufacturing and other fields due to its advantages of high energy conversion efficiency, small size, rapid action response and the like. Meanwhile, the permanent magnet synchronous motor requires reliable and accurate position information for high efficiency and stability, and common position sensors include photoelectric encoders, rotary transformers and switching Hall elements and the like. However, in actual industrial application scenarios, due to small motor installation space, signal interference in harsh environments, hardware cost control and the like, a position sensorless control scheme is developed.

[0003] In a medium-high speed operating range, the traditional position sensorless control method based on the extended back electromotive force model can effectively obtain the estimated value of the motor rotor position and speed, and has been practically applied to industrial production. However, it is greatly affected by operating condition changes, has strong dependence on motor parameters, and due to the influence of factors such as observer chattering and phase shift of linear filter, its estimation accuracy and dynamic characteristics are not ideal, and the scheme still needs to be optimized. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the deficiencies of the prior art and provide a high-speed position sensorless control method in a permanent magnet synchronous motor, which can effectively reduce the influence of operating state changes on system control performance, reduce the dependence on motor parameters, reduce the influence of chattering factors on the system, to some extent, overcome the disadvantages of the traditional linear state observer in balancing system estimation accuracy and disturbance rejection performance, and improve the accuracy and robustness of the position sensorless control scheme.

[0005] The present application adopts the following technical solutions to solve the above technical problems:

[0006] According to the high-speed position sensorless control method in a permanent magnet synchronous motor provided by the present application, the following steps are included:

[0007] Sampling the three-phase current of the motor, and converting the three-phase current into two-phase static coordinate system axis current through Clark transformation;

[0008] inputting the axis current and the axis voltage output by the current controller into a super-twisted sliding mode observer designed based on the current state equation to obtain the observation value of the extended flux differential term;

[0009] The observation value of the extended flux differential term is input into the complex coefficient filter for filtering, and then the inverse tangent calculation is performed to obtain the estimated rotor position including disturbance.

[0010] The estimated rotor position with disturbance is input into the enhanced extended state observer to obtain the estimated values ​​of the motor rotor position and speed.

[0011] As a further optimization scheme of the high-speed position sensorless control method of a permanent magnet synchronous motor according to the present invention, the Park transformation is used to convert The axis current is transformed into the direct and AC axis current in a two-phase rotating coordinate system, and the direct and AC axis current is used for vector control.

[0012] As a further optimization scheme of the high-speed position sensorless control method for a permanent magnet synchronous motor described in the present invention, estimated values ​​of the motor rotor position and speed are used for vector control.

[0013] As a further optimization scheme for the high-speed position sensorless control method of a permanent magnet synchronous motor described in the present invention, the current state equation of the motor is constructed based on the extended flux model; the details are as follows:

[0014] In the two-phase stationary coordinate system, the voltage equation of the permanent magnet synchronous motor is:

[0015] ;

[0016] in, 、 They are the current loop output axis, Shaft stator voltage control quantity; 、 For motors axis, Shaft current; 、 For motors axis, Shaft current; is the stator resistance of the motor, 、 For motor axis, Shaft inductance; is the differential operator, is the motor rotor position angle, is the motor speed, is the permanent magnet flux of the motor;

[0017] Extended flux Combining the permanent magnet flux of the motor and the flux related to saliency, the expression is:

[0018] ;

[0019] The voltage equation of the permanent magnet synchronous motor based on the extended flux model is:

[0020] ;

[0021] Then the current state equation of the motor is obtained as:

[0022] ;

[0023] in, 、 For motor axis, Estimated value of shaft current; the extended magnetic flux exists in the form of differential terms in the current state equation, , The differential term of the extended magnetic flux is The component on the axis, The differential term of the extended magnetic flux is Components on the axis; and The rotor position information is included.

[0024] As a further optimization scheme for the high-speed position sensorless control method of a permanent magnet synchronous motor described in the present invention, a super-twisted sliding mode observer is designed based on the motor current state equation constructed based on the extended flux model to obtain the observed value of the extended flux differential term; specifically, as follows:

[0025] S51. The designed super-twisted sliding mode observer equation is:

[0026] ;

[0027] in, 、 For motor axis, The error between the estimated and actual value of the shaft current; 、 is the adjustable coefficient, is the switch function, is the time variable;

[0028] S52, when the sliding surface is reached 、 After that, the observer will remain on the sliding surface, and the observation value obtained is:

[0029] ;

[0030] in, 、 are the observation values ​​of the extended flux differential term obtained by the super-twisted sliding mode observer. axis, Axis component.

[0031] As a further optimization scheme for the high-speed position sensorless control method of a permanent magnet synchronous motor according to the present invention, the observation value of the extended flux differential term is filtered by a complex coefficient filter; specifically, as follows:

[0032] S61. Designed complex coefficient filter transfer function for:

[0033] ;

[0034] in, is the bandwidth frequency, is the center frequency, is a complex variable, is an imaginary unit;

[0035] S62, the parameters of the complex coefficient filter are set as follows:

[0036] ;

[0037] in, is an adjustable parameter, To estimate the motor speed;

[0038] S63, the observation value and Input complex coefficient filter for filtering.

[0039] As a further optimization scheme of the high-speed position sensorless control method for a permanent magnet synchronous motor described in the present invention, the characteristic of the complex coefficient filter that the signal at the center frequency has no amplitude attenuation and phase shift is utilized to filter out high-frequency noise and vibration effects in the extended flux observation value without generating phase shift.

[0040] As a further optimization scheme for the high-speed position sensorless control method of a permanent magnet synchronous motor according to the present invention, the observed value is subjected to an inverse tangent calculation to obtain an estimated rotor position including disturbance; specifically, as follows:

[0041] S81. The differential term of the extended magnetic flux can be expressed in the form of a phasor as:

[0042] ;

[0043] ;

[0044] in, , is the amplitude of the phasor; , is the disturbance phase angle; is the natural base;

[0045] S82, so the observed value and Perform an inverse tangent calculation to obtain the estimated rotor position including the disturbance :

[0046] .

[0047] As a further optimization scheme for the high-speed position sensorless control method of a permanent magnet synchronous motor according to the present invention, an enhanced extended state observer is used to obtain estimated values ​​of the motor rotor position and speed; specifically, as follows:

[0048] S91. Design the state equation of the enhanced extended state observer as follows:

[0049] ;

[0050] in, is the error between the input signal and the output signal, is its differential term; To estimate the rotor position; is a state variable, , , ; is an estimate of the total disturbance of the system, Including perturbation phase angle and other disturbing factors; , is the input signal gain, is the number of motor pole pairs, is the motor inertia, , is the input signal, is the motor torque reference value; 、 、 、 is the adjustable coefficient;

[0051] S92, adjust the parameters of the enhanced extended state observer, take:

[0052] ;

[0053] in, is the bandwidth parameter, is the gain coefficient, ;

[0054] S93, inputting the estimated rotor position containing disturbance into the enhanced extended state observer to obtain the estimated rotor position and estimated motor speed .

[0055] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0056] (1) Based on the extended flux model, the current state equation of the motor was constructed. Based on this, a rotor position estimation scheme combining a super-twisted sliding mode observer, a complex coefficient filter and an enhanced extended state observer was designed. The control object is a built-in permanent magnet synchronous motor. The motor control strategy adopts a speed and current double closed-loop vector control. The super-twisted sliding mode observer is used to obtain the observation value of the differential term of the motor's extended flux. After the complex coefficient filter preliminarily filters out the disturbance factors, the inverse tangent calculation is performed to obtain the estimated rotor position containing disturbances. The estimated rotor position is then input into the enhanced extended state observer to obtain accurate rotor position and speed. Compared with the traditional scheme, using the extended flux as the observation object can effectively reduce the impact of operating state changes on the system control performance and reduce the dependence on motor parameters.

[0057] (2) The combination of the super-distorted sliding mode observer and the complex coefficient filter in the control scheme proposed by the present invention avoids the phase offset problem caused by the use of linear filters in traditional schemes and reduces the impact of chattering factors on the system;

[0058] (3) The enhanced extended state observer in the control scheme proposed in this invention overcomes to some extent the drawback of the traditional linear state observer that it is difficult to balance the system estimation accuracy and anti-disturbance performance, and improves the accuracy and robustness of the position sensorless control scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a system structure block diagram of the method of the present invention. DETAILED DESCRIPTION

[0060] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0061] The system structure of the method of the present invention is as follows Figure 1 shown.

[0062] The specific implementation steps of the present invention are as follows:

[0063] A medium- and high-speed position sensorless control strategy for a permanent magnet synchronous motor based on an extended flux model includes the following steps:

[0064] S1, after sampling the three-phase current of the motor, transforms the three-phase current into a two-phase stationary coordinate system through Clark transformation. Shaft current;

[0065] S2, the obtained step S1 is transformed by Park transformation The axis current is transformed into the direct-axis current in the two-phase rotating coordinate system, and the direct-axis current is used for vector control;

[0066] S3, based on the extended flux model, constructs the current state equation of the motor. In the two-phase stationary coordinate system, the voltage equation of the permanent magnet synchronous motor is:

[0067] ;

[0068] in, 、 They are the current loop output axis, Shaft stator voltage control quantity; 、 For motor axis, Shaft current; 、 For motor axis, Shaft current; is the stator resistance of the motor, 、 For motor axis, Shaft inductance; is the differential operator, is the motor rotor position angle, is the motor speed, is the permanent magnet flux of the motor;

[0069] Extended flux Combining the flux linkage of the motor's permanent magnets and the flux linkage related to saliency, the expression is:

[0070] ;

[0071] The voltage equation of the permanent magnet synchronous motor based on the extended flux model is:

[0072] ;

[0073] Then the current state equation of the motor is obtained as:

[0074] ;

[0075] in, 、 For motor axis, The estimated value of the shaft current. The extended flux exists in the form of a differential term in the equation, , The differential term of the extended magnetic flux is The component on the axis, The differential term of the extended magnetic flux is Components on the axis; and The rotor position information is included.

[0076] S4, constructing a super-twisted sliding mode observer according to the current state equation obtained in step S3, including the following steps:

[0077] S41. The designed super-twisted sliding mode observer equation is:

[0078] ;

[0079] in, 、 For motor axis, The error between the estimated and actual value of the shaft current; 、 is the adjustable coefficient, is the switch function, is the time variable.

[0080] S42, when the sliding surface is reached 、 After that, the observer will remain on the sliding surface, and the observation value obtained is:

[0081] ;

[0082] in, 、 are the observation values ​​of the extended flux differential term obtained by the super-twisted sliding mode observer. axis, Axis component.

[0083] S5: The extended flux differential term observation value obtained in step S4 is input into a complex coefficient filter to filter out high-frequency noise and chattering effects, including the following steps:

[0084] S51, designed complex coefficient filter transfer function for:

[0085] ;

[0086] in, is the bandwidth frequency, is the center frequency, is a complex variable, is an imaginary unit;

[0087] S52. The complex coefficient filter has the characteristics of no amplitude attenuation and phase shift of the signal at the center frequency. By using these two characteristics, the output signal of the filter can be free of phase shift. Therefore, the parameters are set as:

[0088] ;

[0089] in, is an adjustable parameter, To estimate the motor speed;

[0090] S53, the observation value and Input complex coefficient filter for filtering.

[0091] S6, performing arc tangent calculation on the filtered signal obtained in step S5 to obtain an estimated rotor position including disturbance, comprising the following steps:

[0092] S61. The differential term of the extended magnetic flux can be expressed in the form of a phasor as:

[0093] ;

[0094] ;

[0095] in, is the amplitude of the phasor; is the disturbance phase angle; is the natural base.

[0096] S62, perform arc tangent calculation on the filtered observation value signal to obtain the estimated rotor position containing disturbance :

[0097] ;

[0098] S7, the estimated rotor position including disturbance obtained in step S6 is input into the enhanced extended state observer to obtain accurate estimated rotor position and speed, including the following steps:

[0099] S71. Design the state equation of the enhanced extended state observer as follows:

[0100] ;

[0101] in, is the error between the input signal and the output signal, is its differential term; To estimate the rotor position; is an estimate of the total disturbance of the system, including the disturbance phase angle and other disturbing factors; is a state variable, , , ; is the input signal gain, is the number of motor pole pairs, is the motor inertia, , is the input signal, is the motor torque reference value; 、 、 、 is an adjustable coefficient.

[0102] S72. To accurately estimate the motor rotor position and speed, it is necessary to adjust the parameters of the enhanced extended state observer. The parameters are set to:

[0103] ;

[0104] in, is the bandwidth parameter, is the gain coefficient, .

[0105] S73, inputting the estimated rotor position containing disturbance into the enhanced extended state observer to obtain an accurate estimated rotor position and estimated motor speed .

[0106] Through the design of the enhanced extended state observer, the system has better dynamic performance and estimation accuracy while ensuring anti-interference performance, thereby obtaining accurate estimation of the rotor position and speed.

[0107] The present invention designs a permanent magnet synchronous motor position sensorless expansion strategy based on an extended flux model, which adopts a rotor position estimation scheme that combines a super-twisted sliding mode observer, a complex coefficient filter and an enhanced extended state observer. It not only improves the problems of traditional schemes that are greatly affected by operating conditions and highly dependent on motor parameters, but the combination of the super-twisted sliding mode observer and the complex coefficient filter also greatly reduces the impact of vibration factors on the system. The enhanced extended state observer overcomes to a certain extent the disadvantage of traditional linear state observers that it is difficult to balance system estimation accuracy and anti-disturbance performance, thereby improving the accuracy and robustness of the position sensorless control scheme.

[0108] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for controlling a medium- and high-speed permanent magnet synchronous motor without a position sensor, characterized in that: The following steps are involved: The three-phase current of the sampling motor is transformed into a two-phase stationary coordinate system through Clark transformation. Shaft current; Will Shaft current and current controller output The shaft voltage is input into the super-twisted sliding mode observer designed based on the current state equation to obtain the observed value of the extended flux differential term; The observation value of the extended flux differential term is input into the complex coefficient filter for filtering, and then the inverse tangent calculation is performed to obtain the estimated rotor position including disturbance. The estimated rotor position including disturbance is input into the enhanced extended state observer to obtain the estimated values ​​of the motor rotor position and speed; The motor current state equation is constructed based on the extended flux model; the details are as follows: In the two-phase stationary coordinate system, the voltage equation of the permanent magnet synchronous motor is: ； in, 、 They are the current loop output axis, Shaft stator voltage control quantity; 、 For motors axis, Shaft current; 、 For motors axis, Shaft current; is the stator resistance of the motor, 、 For motors axis, Shaft inductance; is the differential operator, is the motor rotor position angle, is the motor speed, is the permanent magnet flux of the motor; Extended flux Combining the permanent magnet flux of the motor and the flux related to saliency, the expression is: ； The voltage equation of the permanent magnet synchronous motor based on the extended flux model is: ； Then the current state equation of the motor is obtained as: ； in, 、 For motors axis, Estimated value of shaft current; the extended magnetic flux exists in the form of differential terms in the current state equation, , The differential term of the extended magnetic flux is The component on the axis, The differential term of the extended magnetic flux is Components on the axis; and Includes rotor position information; The super-twisted sliding mode observer is designed based on the current state equation of the motor constructed based on the extended flux model to obtain the observed value of the extended flux differential term; the details are as follows: S51. The designed super-twisted sliding mode observer equation is: ； in, 、 For motors axis, The error between the estimated and actual value of the shaft current; 、 is the adjustable coefficient, is the switch function, is the time variable; S52, when the sliding surface is reached 、 After that, the observer will remain on the sliding surface, and the observation value obtained is: ； in, 、 are the observation values ​​of the extended flux differential term obtained by the super-twisted sliding mode observer. axis, Axis component; The observed value is calculated by arc tangent to obtain the estimated rotor position with disturbance; specifically, it is as follows: S81. The differential term of the extended magnetic flux can be expressed in the form of a phasor as: ； ； in, , is the amplitude of the phasor; , is the disturbance phase angle; is the natural base; S82, so the observed value and Perform an inverse tangent calculation to obtain the estimated rotor position including the disturbance : ； The estimated values ​​of the motor rotor position and speed are obtained through the enhanced extended state observer; specifically as follows: S91. Design the state equation of the enhanced extended state observer as follows: ； in, is the error between the input signal and the output signal, is its differential term; To estimate the rotor position; is a state variable, , , ; is an estimate of the total disturbance of the system, Including perturbation phase angle and other disturbing factors; , is the input signal gain, is the number of motor pole pairs, is the motor inertia, , is the input signal, is the motor torque reference value; 、 、 、 is the adjustable coefficient; S92, adjust the parameters of the enhanced extended state observer, take: ； in, is the bandwidth parameter, is the gain coefficient, ; S93, inputting the estimated rotor position containing disturbance into the enhanced extended state observer to obtain the estimated rotor position and estimated motor speed .

2. A method for controlling a medium- and high-speed position sensorless permanent magnet synchronous motor according to claim 1, characterized in that: Through Park transformation The axis current is transformed into the direct and AC axis current in a two-phase rotating coordinate system, and the direct and AC axis current is used for vector control.

3. A method for controlling a medium- and high-speed position sensorless permanent magnet synchronous motor according to claim 1, characterized in that: The estimated values ​​of the motor rotor position and speed are used for vector control.

4. A method for controlling a medium- and high-speed position sensorless permanent magnet synchronous motor according to claim 1, characterized in that: The observations of the extended flux differential term are filtered by a complex coefficient filter; specifically, as follows: S61. Designed complex coefficient filter transfer function for: ； in, is the bandwidth frequency, is the center frequency, is a complex variable, is an imaginary unit; S62, the parameters of the complex coefficient filter are set as follows: ； in, is an adjustable parameter, To estimate the motor speed; S63, the observation value and Input complex coefficient filter for filtering.

5. A method for controlling a permanent magnet synchronous motor at medium and high speed without position sensor according to claim 4, characterized in that: By utilizing the characteristic of no amplitude attenuation and phase shift of the signal at the center frequency of the complex coefficient filter, high-frequency noise and chattering effects in the extended flux observation value are filtered out without causing phase shift.

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