High-speed sensorless control method in permanent magnet synchronous motor

Abstract

The invention discloses a high-speed sensorless control method in a permanent magnet synchronous motor, which relates to the technical field of motor control, constructs a current state equation of the motor based on an extended magnetic flux model, and designs a rotor position estimation scheme combining a super-twisted sliding mode observer, a complex coefficient filter and an enhanced extended state observer according to the current state equation. A control object is a built-in permanent magnet synchronous motor, a motor control strategy adopts rotating speed and current double-closed-loop vector control, an observation value of an extended magnetic flux differential term of the motor is obtained through a super-distortion sliding mode observer, after disturbance factors in the observation value are preliminarily filtered out through a complex coefficient filter, arc tangent calculation is carried out to obtain an estimated rotor position containing disturbance, and the position of the rotor is estimated. And then inputting the result into an enhanced extended state observer so as to obtain accurate rotor position and rotating speed. Compared with a traditional scheme, the method has better dynamic response, estimation precision and robustness.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a method for controlling a permanent magnet synchronous motor in a medium and high speed position sensorless manner. Background Art

[0002] Permanent magnet synchronous motors are widely used in large-scale integrated circuit manufacturing, robot control, precision manufacturing and other fields due to their advantages such as high energy conversion efficiency, small size and rapid action response. At the same time, the high efficiency and stability of permanent magnet synchronous motors require reliable and accurate position information. Commonly used position sensors include photoelectric encoders, rotary transformers and switch Hall elements. However, in actual industrial application scenarios, due to the small installation space of the motor, signal interference in harsh environments, hardware cost control and other situations, position sensorless control solutions have emerged.

[0003] In the medium and high speed operating range, the traditional position sensorless control method based on the extended back-EMF model can effectively obtain the estimated values ​​of the motor rotor position and speed, and has been actually applied in industrial production. However, it is greatly affected by changes in operating conditions, has a strong dependence on motor parameters, and due to factors such as observer jitter and linear filter phase offset, its estimation accuracy and dynamic characteristics are not ideal, and the solution needs to be optimized. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a high-speed position sensorless control method for a permanent magnet synchronous motor. The method can effectively reduce the impact of operating state changes on system control performance, reduce dependence on motor parameters, and reduce the impact of jitter factors on the system. To a certain extent, it overcomes the disadvantage that traditional linear state observers are difficult to balance system estimation accuracy and anti-disturbance performance, and improves the accuracy and robustness of position sensorless control schemes.

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

[0006] A method for controlling a permanent magnet synchronous motor at a medium and high speed without a position sensor according to the present invention comprises the following steps:

[0007] The three-phase current of the motor is sampled and transformed into the αβ axis current of the two-phase stationary coordinate system through Clark transformation;

[0008] The αβ axis current and the αβ axis voltage output by the current controller are input into the super-twisted sliding mode observer designed based on the current state equation to obtain the observed value of the extended magnetic 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 described in the present invention, the αβ axis currents are transformed into AC and DC axis currents in a two-phase rotating coordinate system through Park transformation, and the AC and DC axis currents are 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, the estimated values ​​of the motor rotor position and speed are used for vector control.

[0013] As a further optimization scheme of 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; specifically, as follows:

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

[0015]

[0016] Among them, u α 、u β are the α-axis and β-axis stator voltage control quantities output by the current loop respectively; i α 、i β are the α-axis and β-axis currents of the motor respectively; i d 、i q are the d-axis and q-axis currents of the motor respectively; R s is the stator resistance of the motor, L d , L q are the d-axis and q-axis inductances of the motor respectively; p is the differential operator, θ e is the motor rotor position angle, ω e is the motor speed, λ f is the permanent magnet flux of the motor;

[0017] Extended flux λ ext Combining the permanent magnet flux of the motor and the flux related to salient polarity, the expression is:

[0018] λ ext =λ f +(L d -L q )i d

[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, are the estimated values ​​of the α-axis and β-axis currents of the motor respectively; the extended magnetic flux exists in the form of differential terms in the current state equation, E α is the differential component of the extended magnetic flux on the α axis, E β is the differential component of the extended magnetic flux on the β axis; E α and E α The rotor position information is included.

[0024] As a further optimization scheme of 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 according to the current state equation of the motor constructed based on the extended flux model to obtain the observation value of the extended flux differential term; specifically as follows:

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

[0026]

[0027] in, are the errors between the estimated value and the actual value of the motor's α-axis and β-axis currents, respectively; λ1 and λ2 are adjustable coefficients, sgn() is the switching function, and t is the time variable;

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

[0029]

[0030] in, They are the α-axis and β-axis components of the observed values ​​of the extended flux differential term obtained by the super-twisted sliding mode observer.

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

[0032] S61. The designed complex coefficient filter transfer function G(s) is:

[0033]

[0034] Among them, ω cis the bandwidth frequency, ω0 is the center frequency, s is a complex variable, and j is an imaginary unit;

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

[0036]

[0037] Among them, k is an adjustable parameter, To estimate the motor speed;

[0038] S63, the observed 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 characteristics of the signal without amplitude attenuation and phase shift at the center frequency of the complex coefficient filter are utilized to filter out the high-frequency noise and jitter influence in the extended flux observation value without generating phase shift.

[0040] 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 observed value is calculated by inverse tangent to obtain the estimated rotor position containing 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] in, A is the amplitude of the phasor; is the disturbance phase angle; e is the natural base;

[0044] S82, so for the observed value and Perform an inverse tangent calculation to obtain the estimated rotor position including the disturbance

[0045]

[0046] As a further optimization scheme of the high-speed position sensorless control method of a permanent magnet synchronous motor described in the present invention, the estimated values ​​of the motor rotor position and speed are obtained by an enhanced extended state observer; specifically, as follows:

[0047] S91. Design the state equation of the enhanced extended state observer as follows:

[0048]

[0049] Where ε is the error between the input signal and the output signal, is its differential term; is to estimate the rotor position; z1, z2, z3 are state variables, To estimate the total disturbance of the system, Including perturbation phase angle and other disturbance factors; b = n p / J, b is the input signal gain, n p is the number of motor pole pairs, J is the motor inertia, u is the input signal, is the motor torque reference value; β1, β2, β3, β4 are adjustable coefficients;

[0050] S92, adjust the parameters of the enhanced extended state observer, take:

[0051] β1=3r 2 ω0,β2=r 3 -1,

[0052] Where ω0 is the bandwidth parameter, r is the gain coefficient, 1>r>0;

[0053] S93, inputting the estimated rotor position containing disturbance into the enhanced extended state observer to obtain the estimated rotor position and estimated motor speed

[0054] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0055] (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 disturbance factors are initially filtered out by the complex coefficient filter, the inverse tangent calculation is performed to obtain the estimated rotor position containing disturbances, which 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.

[0056] (2) The combination of the super-distorted sliding mode observer and the complex coefficient filter in the control scheme provided 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;

[0057] (3) The enhanced extended state observer in the control scheme provided by the present invention overcomes to a certain 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

[0058] Figure 1 It is a system structure block diagram of the method of the present invention. DETAILED DESCRIPTION

[0059] In order to make the purpose, 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.

[0060] The system structure of the method of the present invention is as follows Figure 1 shown.

[0061] The specific implementation steps of the present invention are as follows:

[0062] A medium- and high-speed position sensorless control strategy for a permanent magnet synchronous motor based on an extended flux model comprises the following steps:

[0063] S1, after sampling the three-phase current of the motor, transform the three-phase current into the αβ axis current of the two-phase stationary coordinate system through Clark transformation;

[0064] S2, transforming the αβ axis current obtained in step S1 into the AC and DC axis current in the two-phase rotating coordinate system through Park transformation, and the AC and DC axis current is used for vector control;

[0065] S3, based on the extended flux model, the current state equation of the motor is constructed. In the two-phase stationary coordinate system, the voltage equation of the permanent magnet synchronous motor is:

[0066]

[0067] Among them, u α 、u β are the α-axis and β-axis stator voltage control quantities output by the current loop respectively; i α 、i β are the α-axis and β-axis currents of the motor respectively; i d 、i q are the d-axis and q-axis currents of the motor respectively; R s is the stator resistance of the motor, L d , L q are the d-axis and q-axis inductances of the motor respectively; p is the differential operator, θ e is the motor rotor position angle, ω e is the motor speed, λ f is the permanent magnet flux of the motor;

[0068] Extended flux λex Combining the permanent magnet flux of the motor and the flux related to saliency, the expression is:

[0069] λ ext =λ f +(L d -L q )i d

[0070] The voltage equation of the permanent magnet synchronous motor based on the extended flux model is:

[0071]

[0072] Then the current state equation of the motor is obtained as:

[0073]

[0074] in, are the estimated values ​​of the motor's α-axis and β-axis currents, respectively. The extended magnetic flux exists in the equation in the form of a differential term, E α is the differential component of the extended magnetic flux on the α axis, E β is the differential component of the extended magnetic flux on the β axis; E α and E α The rotor position information is included.

[0075] S4, constructing a super-twisted sliding mode observer according to the current state equation obtained in step S3, including the following steps:

[0076] S41. The designed super-twisted sliding mode observer equation is:

[0077]

[0078] in, are the errors between the estimated and actual values ​​of the motor's α-axis and β-axis currents, respectively; λ1 and λ2 are adjustable coefficients, sgn() is the switching function, and t is the time variable.

[0079] S42, when the sliding surface is reached After that, the observer will remain on the sliding surface, and the observed value is:

[0080]

[0081] in, They are the α-axis and β-axis components of the observed values ​​of the extended flux differential term obtained by the super-twisted sliding mode observer.

[0082] 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 jitter effects therein, including the following steps:

[0083] S51, the designed complex coefficient filter transfer function G(s) is:

[0084]

[0085] Among them, ω c is the bandwidth frequency, ω0 is the center frequency, s is a complex variable, and j is an imaginary unit;

[0086] 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, so the parameters are set as:

[0087]

[0088] Among them, k is an adjustable parameter, To estimate the motor speed;

[0089] S53, the observed value and Input complex coefficient filter for filtering.

[0090] S6, the filtered signal obtained in step S5 is subjected to arc tangent calculation to obtain an estimated rotor position including disturbance, comprising the following steps:

[0091] S61. The differential term of the extended magnetic flux can be expressed in the form of a phasor as:

[0092]

[0093] in, is the amplitude of the phasor; is the disturbance phase angle; e is the natural base.

[0094] S62, performing arc tangent calculation on the filtered observation value signal to obtain the estimated rotor position containing disturbance

[0095]

[0096] S7, the estimated rotor position with 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:

[0097] S71. Design the state equation of the enhanced extended state observer as follows:

[0098]

[0099] Where ε 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 disturbance factors; z1, z2, z3 are state variables, b=n p / J is the input signal gain, n p is the number of motor pole pairs, J is the motor inertia, u is the input signal, is the motor torque reference value; β1, β2, β3, β4 are adjustable coefficients.

[0100] S72. In order to accurately estimate the motor rotor position and speed, it is necessary to adjust the parameters of the enhanced extended state observer, and the parameters are set as follows:

[0101] β1=3r 2 ω0,β2=r 3 -1,

[0102] Among them, ω0 is the bandwidth parameter, r is the gain coefficient, 1>r>0.

[0103] 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

[0104] Through the design of enhanced extended state observer, the system has better dynamic performance and estimation accuracy while ensuring anti-interference performance, so as to obtain accurate estimation of rotor position and speed.

[0105] The permanent magnet synchronous motor position sensorless expansion strategy based on the extended flux model designed in the present invention 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 the traditional scheme being greatly affected by the operating conditions and highly dependent on the motor parameters, but the combination of the super-twisted sliding mode observer and the complex coefficient filter also greatly reduces the impact of the jitter factor on the system. The enhanced extended state observer overcomes to a certain extent the disadvantage that the traditional linear state observer is difficult to balance the system estimation accuracy and anti-disturbance performance, thereby improving the accuracy and robustness of the position sensorless control scheme.

[0106] The above description is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for controlling a permanent magnet synchronous motor at a medium and high speed without a position sensor, characterized in that: The following steps are involved: The three-phase current of the motor is sampled and transformed into the αβ axis current of the two-phase stationary coordinate system through Clark transformation; The αβ axis current and the αβ axis voltage output by the current controller are input into the super-twisted sliding mode observer designed based on the current state equation to obtain the observed value of the extended magnetic 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 with disturbance is input into the enhanced extended state observer to obtain the estimated values ​​of the motor rotor position and speed.

2. A method for controlling a permanent magnet synchronous motor at a medium and high speed without a position sensor according to claim 1, characterized in that: The αβ axis currents are transformed into AC and DC axis currents in a two-phase rotating coordinate system through Park transformation, and the AC and DC axis currents are used for vector control.

3. A method for controlling a permanent magnet synchronous motor at a medium and high speed without a position sensor 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 permanent magnet synchronous motor at medium and high speed without position sensor according to claim 1, characterized in that: The current state equation of the motor 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: Among them, u α 、u β are the α-axis and β-axis stator voltage control quantities output by the current loop respectively; i α 、i β are the α-axis and β-axis currents of the motor respectively; i d 、i q are the d-axis and q-axis currents of the motor respectively; R s is the stator resistance of the motor, L d , L q are the d-axis and q-axis inductances of the motor respectively; p is the differential operator, θ e is the motor rotor position angle, ω e is the motor speed, λ f is the permanent magnet flux of the motor; Extended flux λ ext Combining the permanent magnet flux of the motor and the flux related to salient polarity, the expression is: l ext =λ f +(L d -L q )i d 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, are the estimated values ​​of the α-axis and β-axis currents of the motor respectively; the extended magnetic flux exists in the form of differential terms in the current state equation, E α is the differential component of the extended magnetic flux on the α axis, E β is the differential component of the extended magnetic flux on the β axis; E α and E α The rotor position information is included.

5. A method for controlling a permanent magnet synchronous motor at a medium and high speed without position sensor according to claim 4, characterized in that: According to the current state equation of the motor constructed based on the extended flux model, the super-twisted sliding mode observer is designed 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, are the errors between the estimated value and the actual value of the motor's α-axis and β-axis currents, respectively; λ1 and λ2 are adjustable coefficients, sgn() is the switching function, and t is the time variable; S52, when the sliding surface is reached After that, the observer will remain on the sliding surface, and the observed value is: in, They are the α-axis and β-axis components of the observed values ​​of the extended flux differential term obtained by the super-twisted sliding mode observer.

6. A method for controlling a permanent magnet synchronous motor at a medium and high speed without position sensor according to claim 5, characterized in that: The observations of the extended flux differential term are filtered by a complex coefficient filter; specifically as follows: S61. The designed complex coefficient filter transfer function G(s) is: Among them, ω c is the bandwidth frequency, ω0 is the center frequency, s is a complex variable, and j is an imaginary unit; S62, the parameters of the complex coefficient filter are set as follows: Among them, k is an adjustable parameter, To estimate the motor speed; S63, the observed value and Input complex coefficient filter for filtering.

7. A method for controlling a permanent magnet synchronous motor at medium and high speed without position sensor according to claim 6, 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 jitter influence in the extended flux observation value can be filtered out without causing phase shift.

8. A method for controlling a permanent magnet synchronous motor at medium and high speed without position sensor according to claim 6, characterized in that: The observed value is calculated by inverse tangent to obtain the estimated rotor position with disturbance; specifically, as follows: S81. The differential term of the extended magnetic flux can be expressed in the form of a phasor as: in, A is the amplitude of the phasor; is the disturbance phase angle; e is the natural base; S82, so for the observed value and Perform an inverse tangent calculation to obtain the estimated rotor position including the disturbance 9. A method for controlling a permanent magnet synchronous motor at medium and high speed without position sensor according to claim 8, characterized in that: 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: Where ε is the error between the input signal and the output signal, is its differential term; is to estimate the rotor position; z1, z2, z3 are state variables, To estimate the total disturbance of the system, Including perturbation phase angle and other disturbance factors; b = n p / J, b is the input signal gain, n p is the number of motor pole pairs, J is the motor inertia, u is the input signal, is the motor torque reference value; β1, β2, β3, β4 are adjustable coefficients; S92, adjust the parameters of the enhanced extended state observer, take: β1=3r 2 ω0, β2=r 3 -1, Where ω0 is the bandwidth parameter, r is the gain coefficient, 1>r>0; S93, inputting the estimated rotor position containing disturbance into the enhanced extended state observer to obtain the estimated rotor position and estimated motor speed

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