Position sensorless control method and system based on intermediate function disturbance observer

Abstract

The invention discloses a sensorless control method and system based on an intermediate function disturbance observer, a traditional disturbance observer is improved by designing an intermediate function, differential calculation does not need to be carried out on a state variable when counter electromotive force is estimated, noise signals generated during differential calculation can be avoided, and the accuracy of estimation of counter electromotive force is improved. And a filter does not need to be additionally arranged for eliminating the noise signal. The signal processing method is simple, feasible, reliable and practical, the dynamic performance of the system is improved, the method can be widely applied to permanent magnet synchronous motor control, and extra hardware overhead is not needed.

Description

Technical Field

[0001] The invention relates to motor control, and in particular to a position sensorless control method and system based on an intermediate function disturbance observer. Background Art

[0002] In the position sensorless control of permanent magnet synchronous motor (PMSM), high-frequency injection methods are commonly used at low speeds, such as rotating high-frequency voltage injection method, pulsating high-frequency voltage injection method, square wave injection method, etc.; model reference adaptive method, sliding mode observer method, disturbance observer method, etc. are commonly used at medium and high speeds. Among them, the traditional disturbance observer method usually designs a disturbance observer for the feedback loop, using the current i in the stationary coordinate system α 、i β and voltage u α 、u β As the input of the disturbance observer, the estimated value of the back EMF is obtained Combined with the phase-locked loop (PLL) and the corresponding position compensation θ comp , the rotor position angle is estimated and speed See also Figure 1 .

[0003] However, in the estimation of back electromotive force, the traditional disturbance observer needs to perform differential calculations on the state variables, which will generate noise signals. It is necessary to additionally design filters to eliminate the influence of the noise signals, and the addition of filters will affect the dynamic performance of the system. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a position sensorless control method and system based on an intermediate function disturbance observer, which does not require differential calculation of state variables when estimating back electromotive force.

[0005] Technical solution: A position sensorless control method based on an intermediate function disturbance observer of the present invention comprises:

[0006] The improved disturbance observer expression is:

[0007]

[0008] Where, L is the disturbance observer gain; R s is the inductance, L s is the stator phase winding resistance; intermediate function is the back electromotive force e αβ The estimated value of αβ is the current in the two-phase stationary coordinate system; uαβ is the voltage in the two-phase stationary coordinate system; is the derivative of the intermediate function f;

[0009] Based on the estimated value of back EMF Combined with PLL and corresponding position compensation, the rotor position angle is estimated and speed

[0010] Furthermore, in the stationary coordinate system, the current state equation of the surface-mounted permanent magnet synchronous motor is:

[0011]

[0012] Among them, i α 、i β is the current component in the two-phase stationary coordinate system; u α 、u β is the voltage component in the two-phase stationary coordinate system; e α 、e β is the back electromotive force in the two-phase stationary coordinate system;

[0013] The time domain differential equation of the current state equation is expressed as:

[0014]

[0015] in, for i αβ The derivative of

[0016] The traditional disturbance observer model is:

[0017]

[0018] in, for The derivative of ; L is the disturbance observer gain;

[0019] Substituting the time domain differential equation of the current state equation into the disturbance observer model, the final expression of the traditional disturbance observer is obtained:

[0020] The final expression of the traditional disturbance observer is improved by using the intermediate function f to obtain the improved disturbance observer expression.

[0021] Furthermore, the back electromotive force e αβ Calculated by the following formula:

[0022]

[0023] Where p is the number of motor pole pairs, ω r is the rotor angular velocity, ψf is the permanent magnet flux, and θ is the rotor position angle.

[0024] Furthermore, the corresponding position compensation is:

[0025]

[0026] Furthermore, the position sensorless control method based on the intermediate function disturbance observer also includes:

[0027] The three-phase stator current i of the permanent magnet synchronous motor a 、i b 、i c The current component i in the two-phase stationary coordinate system is obtained by 3s / 2s coordinate transformation α 、i β ;

[0028] Current component i α 、i β After 2s / 2r coordinate transformation, the current is obtained

[0029] Set the rated speed ω ref With estimated speed After making the difference, the current i is obtained through speed loop adjustment. q ;

[0030] Current i q With current After comparison, the q-axis voltage u is obtained through current loop regulation. q ;

[0031] D-axis current given reference value i dref With current After comparison, the d-axis voltage u is obtained through current loop regulation. d ;

[0032] Voltage u d and u q After 2r / 2s coordinate transformation, the voltage u in the two-phase stationary coordinate system is obtained α 、u β , according to the voltage u α 、u β Obtain PWM drive signal to drive the permanent magnet synchronous motor.

[0033] Further,

[0034]

[0035] Further,

[0036]

[0037] in, is the estimated value of the d-axis current, is the estimated value of the q-axis current.

[0038] Further,

[0039]

[0040] Where θ is the rotor position angle.

[0041] A position sensorless control system based on an intermediate function disturbance observer of the present invention comprises:

[0042] Improved disturbance observer, with voltage u α 、u β and current i α 、i β As input, the rotor position angle is estimated according to the control method described and speed

[0043] Furthermore, the position sensorless control system based on the intermediate function disturbance observer further includes:

[0044] 3s / 2s coordinate transformation module, used to transform the three-phase stator current i of the permanent magnet synchronous motor a 、i b 、i c Get the current component i in the two-phase stationary coordinate system α 、i β , current component i α 、i β Input the improved disturbance observer and 2s / 2r coordinate transformation module respectively;

[0045] 2s / 2r coordinate transformation module, used to transform the current component i α 、i β Get current

[0046] The speed loop adjustment module is used to adjust the speed according to the rated speed ω ref With speed Get the q-axis current i q ;

[0047] The first current loop adjustment module is used to adjust the current according to the q-axis current i q With current Get the q-axis voltage u q ;

[0048] The second current loop adjustment module is used to set a reference value i according to the d-axis current dref With current Get the d-axis voltage ud ;

[0049] 2r / 2s coordinate transformation module, used to transform the voltage u d and u q Get the voltage u in the two-phase stationary coordinate system α 、u β ;

[0050] SVPWM module, used to adjust the voltage u α 、u β Output PWM drive signal;

[0051] The inverter is used to drive the permanent magnet synchronous motor according to the PWM drive signal; the voltage u output by the inverter α 、u β Enter the improved disturbance observer.

[0052] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the present invention designs an intermediate function to optimize the disturbance observer, so that when estimating the back electromotive force, it is not necessary to perform differential calculation on the state variable, thereby avoiding the noise signal generated during the differential calculation, reducing the influence of system harmonics, and no longer needing to add a filter to eliminate the noise signal, and adjusting the filter parameters. The present invention reduces the complexity of the system hardware and software, and can effectively improve the dynamic performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is the block diagram of the traditional disturbance observer;

[0054] Figure 2 is a structural block diagram of an improved disturbance observer in an embodiment of the present invention;

[0055] Figure 3 It is a structural block diagram of a position sensorless control system based on an intermediate function disturbance observer provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The present invention will be further described below in conjunction with the accompanying drawings.

[0057] Attached Figures 1 to 3 The reference numerals in the figures are as follows:

[0058] 1. Speed ​​loop regulation module; 2. First current loop regulation module; 3. Second current loop regulation module; 4. 2r / 2s coordinate transformation module; 5. SVPWM module; 6. Inverter; 7. Permanent magnet synchronous motor; 8. 3s / 2s coordinate transformation module; 9. Improved disturbance observer; 10. 2s / 2r coordinate transformation module.

[0059] The embodiment of the present invention provides a position sensorless control method based on an intermediate function disturbance observer, comprising the following steps:

[0060] (1) The three-phase stator current i of the permanent magnet synchronous motor 7 is a 、i b 、i c Perform 3s / 2s coordinate transformation to obtain the current component i in the two-phase stationary coordinate system α 、i β .

[0061]

[0062] (2) Design an improved disturbance observer, see Figure 2 .

[0063] In the stationary coordinate system, the current state equation of the surface-mounted permanent magnet synchronous motor is:

[0064]

[0065] Among them, u α 、u β is the voltage component in the two-phase stationary coordinate system, e α 、e β is the back electromotive force in the two-phase stationary coordinate system, R s is the inductance, L s is the stator phase winding resistance.

[0066] The time domain differential equation of the current state equation is expressed as:

[0067]

[0068] Among them, i αβ is the current in the two-phase stationary coordinate system, u αβ is the voltage of the two-phase stationary coordinate system, e αβ is the back electromotive force in the two-phase stationary coordinate system; for i αβ The derivative of

[0069]

[0070] Back EMF αβ Calculated by the following formula:

[0071]

[0072] Where p is the number of motor pole pairs, ω r is the rotor angular velocity, ψ f is the permanent magnet flux, and θ is the rotor position angle.

[0073] The traditional disturbance observer model is:

[0074]

[0075] Where L is the disturbance observer gain, is the back electromotive force e αβ The estimated value of for The derivative of .

[0076] Substituting the time domain differential equation of the current state equation into the disturbance observer model, the final expression of the traditional disturbance observer is obtained:

[0077] The final expression of the traditional disturbance observer is transformed into:

[0078]

[0079] Designing intermediate functions

[0080] The improved disturbance observer expression is obtained through the intermediate function f:

[0081]

[0082] in, is the derivative of the intermediate function f.

[0083] The estimated back EMF value is Input into the phase-locked loop (PLL) to obtain the speed information By speed information Integrate and compare with it after position compensation to get the rotor position angle

[0084] The corresponding position compensation is:

[0085]

[0086] (3) Current component i α 、i β After 2s / 2r coordinate transformation, the current is obtained

[0087]

[0088] in, is the estimated value of the d-axis current, is the estimated value of the q-axis current.

[0089] (4) Set the rated speed ω ref With estimated speed After making the difference, the q-axis current i is obtained through speed loop adjustment. q ;

[0090] (5) Current i q With current After comparison, the q-axis voltage u is obtained through current loop regulation. q ;

[0091] (6) D-axis current given reference value i dref With current After comparison, the d-axis voltage u is obtained through current loop regulation. d ;

[0092] (7) Voltage u d and u q After 2r / 2s coordinate transformation, the voltage u in the two-phase stationary coordinate system is obtained α 、u β , according to the voltage u α 、u β Obtain PWM drive signal to drive the permanent magnet synchronous motor.

[0093]

[0094] Where θ is the rotor position angle.

[0095] The present invention replaces the variable i by designing an intermediate function αβ Differentiation calculation avoids the variable i αβ Noise signals are generated during differential calculations, and no additional filter needs to be designed to eliminate noise signals when estimating back electromotive force. The signal processing method is simple, reliable and practical, and improves the dynamic performance of the system. The present invention can be widely used in permanent magnet synchronous motor control without requiring additional hardware overhead.

[0096] like Figure 3 As shown, an embodiment of the present invention also provides a position sensorless control system based on an intermediate function disturbance observer, including a speed loop adjustment module 1, a first current loop adjustment module 2, a second current loop adjustment module 3, a 2r / 2s coordinate transformation module 4, an SVPWM (Space Vector Pulse Width Modulation, two-level space vector modulation) module 5, an inverter 6, a 3s / 2s coordinate transformation module 8, an improved disturbance observer 9 and a 2s / 2r coordinate transformation module 10.

[0097] The 3s / 2s coordinate transformation module 8 is based on the three-phase stator current i of the permanent magnet synchronous motor 7 a 、i b 、i c Get the current component i in the two-phase stationary coordinate systemα 、i β The voltage u output by inverter 6 is α 、u β and the current i output by the 3s / 2s coordinate transformation module 8 α 、i β As the input of the improved disturbance observer 9, the control method according to the embodiment of the present invention estimates the rotor position angle and speed The rotor position angle They are input to the 2r / 2s coordinate transformation module 4 and the 2s / 2r coordinate transformation module 10 respectively. With rated speedω ref After the difference is made, it is input into the speed loop regulation module 1, and after the speed loop regulation module 1 is regulated, the q-axis current i is obtained. q . The 2s / 2r coordinate transformation module 10 is based on the current component i α 、i β And the rotor position angle output by the improved disturbance observer 9 Get current The q-axis current i output by the speed loop regulation module 1 q The current output by the 2s / 2r coordinate transformation module 10 After comparison, the first current loop regulation module 2 is input and the q-axis voltage u is output. q . The d-axis current given reference value i dref The current output by the 2s / 2r coordinate transformation module 10 After comparison, it is input into the second current loop regulation module 3, and the d-axis voltage u is output. d . 2r / 2s coordinate transformation module 4 according to voltage u d and u q Get the voltage u in the two-phase stationary coordinate system α 、u β Voltage u α 、u β The SVPWM module 5 is input, a PWM driving signal is output, and then the permanent magnet synchronous motor 7 is driven by the inverter 6 .

Claims

1. A position sensorless control method based on an intermediate function disturbance observer, characterized in that: include: The improved disturbance observer expression is: Where, L is the disturbance observer gain; R s is the inductance, L s is the stator phase winding resistance; intermediate function is the back electromotive force e αβ The estimated value of αβ is the current in the two-phase stationary coordinate system; u αβ is the voltage in the two-phase stationary coordinate system; is the derivative of the intermediate function f; Based on the estimated value of back EMF Combined with PLL and corresponding position compensation, the rotor position angle is estimated and speed 2. The position sensorless control method based on the intermediate function disturbance observer according to claim 1 is characterized in that: In the stationary coordinate system, the current state equation of the surface-mounted permanent magnet synchronous motor is: Among them, i α 、i β is the current component in the two-phase stationary coordinate system; u α 、u β is the voltage component in the two-phase stationary coordinate system; e α 、e β is the back electromotive force in the two-phase stationary coordinate system; The time domain differential equation of the current state equation is expressed as: in, for i αβ The derivative of The traditional disturbance observer model is: in, for The derivative of ; L is the disturbance observer gain; Substituting the time domain differential equation of the current state equation into the disturbance observer model, the final expression of the traditional disturbance observer is obtained: The final expression of the traditional disturbance observer is improved by using the intermediate function f to obtain the improved disturbance observer expression.

3. The position sensorless control method based on the intermediate function disturbance observer according to claim 2 is characterized in that: Back EMF αβ Calculated by the following formula: Where p is the number of motor pole pairs, ω r is the rotor angular velocity, ψ f is the permanent magnet flux, and θ is the rotor position angle.

4. The position sensorless control method based on the intermediate function disturbance observer according to claim 3 is characterized in that: The corresponding position compensation is:

5. The position sensorless control method based on the intermediate function disturbance observer according to any one of claims 1 to 4, characterized in that: Also includes: The three-phase stator current i of the permanent magnet synchronous motor a 、i b 、i c The current component i in the two-phase stationary coordinate system is obtained by 3s / 2s coordinate transformation α 、i β ; Current component i α 、i β After 2s / 2r coordinate transformation, the current is obtained Set the rated speed ω ref With estimated speed After making the difference, the current i is obtained through speed loop adjustment. q ; Current i q With current After comparison, the q-axis voltage u is obtained through current loop regulation. q ; D-axis current given reference value i dref With current After comparison, the d-axis voltage u is obtained through current loop regulation. d ; Voltage u d and u q After 2r / 2s coordinate transformation, the voltage u in the two-phase stationary coordinate system is obtained α 、u β , according to the voltage u α 、u β Obtain PWM drive signal to drive permanent magnet synchronous motor.

6. The position sensorless control method based on the intermediate function disturbance observer according to claim 5 is characterized in that:

7. The position sensorless control method based on the intermediate function disturbance observer according to claim 5 is characterized in that: in, is the estimated value of the d-axis current, is the estimated value of the q-axis current.

8. The position sensorless control method based on intermediate function disturbance observer according to claim 5 is characterized in that: Where θ is the rotor position angle.

9. A position sensorless control system based on an intermediate function disturbance observer, characterized in that: include: Improved disturbance observer (9), with voltage u α 、u β and current i α 、i β As input, The control method according to claim 1 estimates the rotor position angle and speed 10. The position sensorless control system based on the intermediate function disturbance observer according to claim 9, characterized in that: Also includes: The 3s / 2s coordinate transformation module (8) is used to transform the three-phase stator current i of the permanent magnet synchronous motor (7) a 、i b 、i c Get the current component i in the two-phase stationary coordinate system α 、i β , current component i α 、i β Inputting the improved disturbance observer (9) and the 2s / 2r coordinate transformation module (10) respectively; 2s / 2r coordinate transformation module (10), used for transforming the current component i α 、i β Get current The speed loop adjustment module (1) is used to adjust the speed according to the rated speed ω ref With speed Get the q-axis current i q ; The first current loop adjustment module (2) is used to adjust the current according to the q-axis current i q With current Get the q-axis voltage u q ; The second current loop adjustment module (3) is used to set a reference value i according to the d-axis current dref With current Get the d-axis voltage u d ; 2r / 2s coordinate transformation module (4), used to convert the voltage u d and u q Get the voltage u in the two-phase stationary coordinate system α 、u β ; SVPWM module (5), used to adjust the voltage u α 、u β Output PWM drive signal; The inverter (6) is used to drive the permanent magnet synchronous motor (7) according to the PWM drive signal; the voltage u output by the inverter (6) α 、u β Enter the improved disturbance observer (9).

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