Method and apparatus for observing position of rotor of alternating current motor

Abstract

The application discloses an AC motor rotor position observation method and device, and relates to the technical field of AC motors. The AC motor rotor position observation method comprises the following steps: acquiring real-time information of an AC motor; constructing a stator flux linkage observer; acquiring an observed value of a stator flux linkage according to the real-time information of the AC motor and the stator flux linkage observer; acquiring a direct-axis flux linkage projection and a quadrature-axis flux linkage projection according to the observed value of the stator flux linkage; predicting an observer balance point deviation phenomenon according to the direct-axis flux linkage projection, so as to acquire an observer balance point deviation correction amount; acquiring a rotor position estimation error according to the observer balance point deviation correction amount and the quadrature-axis flux linkage projection; and acquiring a final rotor position observed value according to the rotor position estimation error. The application can effectively prevent the observer from converging to an unexpected balance point under extreme working conditions, and can further improve the dynamic performance of motor rotor position observation.

Description

Technical Field

[0001] This application relates to the field of AC motor technology, specifically to an AC motor rotor position observation method and an AC motor rotor position observation device. Background Technology

[0002] In many AC motor applications, where position sensors are not installed, AC motor drivers are required to observe the rotor position of the AC motor to achieve precise control of the AC current. Currently, commonly used AC motor rotor position observation methods are mainly divided into two categories: the fundamental frequency model method and the high-frequency injection method. The high-frequency injection method requires the AC motor to have a certain degree of salient pole effect and cannot be used as a universal method for AC motor rotor position observation. The fundamental frequency model method is further divided into the flux linkage observation method and the back EMF voltage observation method. Since the amplitude of the back EMF voltage of an AC motor gradually weakens as the motor speed decreases, while the amplitude of the flux linkage of an AC motor can remain approximately constant across the entire speed range, the flux linkage observation method can be used as a universal and high-performance method for AC motor rotor position observation. However, the flux linkage observation method suffers from multi-equilibrium-point convergence problems. Under extreme conditions such as motor parameter mismatch, direct runaway start, sudden acceleration / deceleration, and sudden load changes, when the observer converges to an undesirable equilibrium point, it can lead to incorrect rotor position observation, resulting in motor driver failure and shutdown. Summary of the Invention

[0003] The purpose of this invention is to provide a method for observing the rotor position of an AC motor to at least solve one of the above-mentioned technical problems.

[0004] One aspect of the present invention provides a method for observing the rotor position of an AC motor, the method comprising: Obtain real-time information about AC motors; Construct a stator flux linkage observer; The stator flux linkage observation value is obtained based on the real-time information of the AC motor and the stator flux linkage observer. The direct-axis flux linkage projection and the quadrature-axis flux linkage projection are obtained based on the stator flux linkage observation values. The observer equilibrium point offset phenomenon is predicted based on the direct-axis magnetic flux projection, thereby obtaining the observer equilibrium point offset correction amount; The rotor position estimation error is obtained based on the observer's equilibrium point offset correction and the cross-axis flux projection. The final rotor position observation value is obtained based on the rotor position estimation error.

[0005] Optionally, the formula for the stator flux linkage observer is as follows: ; in, ψ dvis Direct-axis stator flux linkage observations; ψ qv These are observations of the cross-axis stator flux linkage; θ e The observed value of the motor position angle; ψ r It is the rotor flux linkage amplitude. L d For the direct-axis stator inductance of a synchronous motor; k d It is the observation gain of the direct-axis stator flux linkage; k q It is the cross-axis stator flux linkage observation gain; i d It is the direct-axis stator current; i q It is the quadrature-axis stator current; d For differential operators, dt Represents the derivative with respect to time; u d It is the direct-axis stator voltage; u q It is the quadrature-axis stator voltage; R For stator resistance, θ This is the motor position angle.

[0006] Optionally, the stator flux linkage observation value obtained based on the real-time information of the AC motor and the stator flux linkage observer is obtained by the following formula: ; in, ψ dvr is The direct-axis flux projection formed by modulating the rotor flux amplitude with rotor position estimation error; ψ qvr The quadrature-axis flux projection is formed by modulating the rotor flux amplitude with rotor position estimation error. θ This is the actual motor position angle; ψ r It is the rotor flux linkage amplitude; ψ dv is Direct-axis stator flux linkage observations; ψ qv These are observations of the cross-axis stator flux linkage; L d For the direct-axis stator inductance of a synchronous motor; i d It is the direct-axis stator current; i q It is the quadrature-axis stator current; L q This refers to the quadrature-axis stator inductance of a synchronous motor.

[0007] Optionally, the prediction of the observer equilibrium point offset phenomenon based on the direct-axis flux linkage projection, thereby obtaining the observer equilibrium point offset correction amount, is obtained by the following formula: ; in; g infer This is the observer equilibrium point offset correction amount. δ As the attenuation factor, λ As a positive motivating factor, η It is a negative motivating factor; ψ dvr is The direct-axis flux projection formed by modulating the rotor flux amplitude with rotor position estimation error; ψ qvr The quadrature-axis flux projection is formed by modulating the rotor flux amplitude with rotor position estimation error. ψ r It is the rotor flux linkage amplitude.

[0008] Optionally, the rotor position estimation error obtained based on the observer equilibrium point offset correction and the cross-axis flux projection is obtained by the following formula: ; in, e corr The error is the corrected rotor position estimation error; g infer This is the observer equilibrium point offset correction amount. ψ qvr The quadrature-axis flux projection is formed by modulating the rotor flux amplitude with rotor position estimation error. ψ r It is the rotor flux linkage amplitude.

[0009] Optionally, the final rotor position observation value is obtained based on the rotor position estimation error using the following formula: ; in, e corr The error is the corrected rotor position estimation error; dt Represents the derivative with respect to time; kp The proportional gain of the phase-locked loop; ki represents the integral coefficient of the phase-locked loop.

[0010] Optionally, the attenuation factor δ The upper limit is 0.707, and the attenuation factor is... δ The lower limit is 0.

[0011] Optionally, the attenuation factor δ The upper limit is 0.5.

[0012] This application also provides an AC motor rotor position observation device, the AC motor rotor position observation device comprising: Real-time information acquisition module, the real-time information acquisition module is used to acquire real-time information of AC motor; A stator flux linkage observer construction module, which is used to construct a stator flux linkage observer; An observation acquisition module is used to acquire stator flux linkage observation values ​​based on the real-time information of the AC motor and the stator flux linkage observer. The projection information acquisition module is used to acquire the direct-axis flux linkage projection and the quadrature-axis flux linkage projection based on the acquired stator flux linkage observation values. The correction amount acquisition module is used to predict the observer equilibrium point offset phenomenon based on the direct axis magnetic flux projection, thereby obtaining the observer equilibrium point offset correction amount. An error acquisition module is used to acquire the rotor position estimation error based on the observer balance point offset correction and the cross-axis flux projection. A position observation acquisition module is used to acquire the final rotor position observation value based on the rotor position estimation error.

[0013] The AC motor rotor position observation method of this application first uses a stator flux linkage observer to observe the stator flux linkage of the AC motor. Then, it uses the observed stator flux linkage values ​​to calculate the direct-axis flux linkage projection and the quadrature-axis flux linkage projection. Furthermore, it uses the direct-axis flux linkage projection to predict the observer's equilibrium point shift. Finally, it uses the quadrature-direct-axis flux linkage projection combined with a phase-locked loop to observe the motor rotor position. This method can effectively prevent the observer from converging to an undesirable equilibrium point under extreme operating conditions and can further improve the dynamic performance of motor rotor position observation. Attached Figure Description

[0014] Figure 1 This is a schematic flowchart of an embodiment of an AC motor rotor position observation method according to this application; Figure 2 This is a schematic diagram of the equilibrium point offset prediction of a flux linkage observer according to an embodiment of this application. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0016] like Figure 1 The methods for observing the rotor position of an AC motor shown include: Obtain real-time information about AC motors; Construct a stator flux linkage observer; The stator flux linkage observation value is obtained based on the real-time information of the AC motor and the stator flux linkage observer. The direct-axis flux linkage projection and the quadrature-axis flux linkage projection are obtained based on the stator flux linkage observation values. The observer equilibrium point offset phenomenon is predicted based on the direct-axis magnetic flux projection, thereby obtaining the observer equilibrium point offset correction amount; The rotor position estimation error is obtained based on the observer's equilibrium point offset correction and the cross-axis flux projection. The final rotor position observation value is obtained based on the rotor position estimation error.

[0017] In this embodiment, the formula for the stator flux linkage observer is as follows: ; in, ψ dv is Direct-axis stator flux linkage observations; ψ qv These are observations of the cross-axis stator flux linkage; θ e The observed value of the motor position angle; ψr It is the rotor flux linkage amplitude. L d For the direct-axis stator inductance of a synchronous motor; k d It is the observation gain of the direct-axis stator flux linkage; k q It is the cross-axis stator flux linkage observation gain; i d It is the direct-axis stator current; i q It is the quadrature-axis stator current;d For differential operators, dt Represents the derivative with respect to time; u d It is the direct-axis stator voltage; u q It is the quadrature-axis stator voltage; R For stator resistance, θ This is the motor position angle.

[0018] In this embodiment, the stator flux linkage observation value is obtained based on the real-time information of the AC motor and the stator flux linkage observer using the following formula: ; in, ψ dvr is The direct-axis flux projection formed by modulating the rotor flux amplitude with rotor position estimation error; ψ qvr The quadrature-axis flux projection is formed by modulating the rotor flux amplitude with rotor position estimation error. θ This is the actual motor position angle; ψ r It is the rotor flux linkage amplitude; ψdv is Direct-axis stator flux linkage observations; ψ qv These are observations of the cross-axis stator flux linkage; L d For the direct-axis stator inductance of a synchronous motor; i d It is the direct-axis stator current; i q It is the quadrature-axis stator current; L q This refers to the quadrature-axis stator inductance of a synchronous motor.

[0019] In this embodiment, the prediction of the observer equilibrium point offset phenomenon based on the direct-axis flux linkage projection, thereby obtaining the observer equilibrium point offset correction amount, is obtained through the following formula: ; in; g infer This is the observer equilibrium point offset correction amount. δ As the attenuation factor, λ As a positive motivating factor, η It is a negative motivating factor; ψ dvr is The direct-axis flux projection formed by modulating the rotor flux amplitude with rotor position estimation error; ψ qvr The quadrature-axis flux projection is formed by modulating the rotor flux amplitude with rotor position estimation error. ψr It is the rotor flux linkage amplitude.

[0020] In this embodiment, the rotor position estimation error obtained based on the observer equilibrium point offset correction and the cross-axis flux linkage projection is obtained by the following formula: ; in, e corr The error is the corrected rotor position estimation error; g infer This is the observer equilibrium point offset correction amount. ψ qvr The quadrature-axis flux projection is formed by modulating the rotor flux amplitude with rotor position estimation error. ψ r It is the rotor flux linkage amplitude.

[0021] In this embodiment, the final rotor position observation value is obtained based on the rotor position estimation error using the following formula: ; in, e corr The error is the corrected rotor position estimation error; dt Represents the derivative with respect to time; kp The proportional gain of the phase-locked loop; ​ represents the integral coefficient of the phase-locked loop.

[0022] In this embodiment, the attenuation factor ​ The upper limit is 0.707, and the attenuation factor is... ​ The lower limit is 0.

[0023] In this embodiment, the attenuation factor ​ The upper limit is 0.5.

[0024] The following examples further illustrate this application in detail. It is understood that these examples do not constitute any limitation on this application.

[0025] The stator flux linkage equation of the AC motor in the synchronous rotating coordinate system is as follows: (1) In equation (1), ​ d and ​ q These are the direct-axis stator flux linkage and the quadrature-axis stator flux linkage, respectively. d For differential operators, ​ It represents the derivative with respect to time. u d and u qThese are the direct-axis stator voltage and the quadrature-axis stator voltage, respectively. i d and i q These are the direct-axis stator current and the quadrature-axis stator current, respectively. R For stator resistance, ​ This is the motor position angle.

[0026] According to equation (1), the stator flux linkage observer of the AC motor can be constructed as follows: (2) In equation (2), ​ dv and ​ qv These are the observation values ​​of the direct-axis stator flux linkage and the quadrature-axis stator flux linkage, respectively. ​ e This represents the observed position angle of the motor. ​ r This refers to the rotor flux linkage amplitude; here, a synchronous motor is used as an example. L d This refers to the direct-axis stator inductance of a synchronous motor. k d and k q These are the observation gains of the direct-axis stator flux linkage and the quadrature-axis stator flux linkage, respectively. k d and k q It can be calculated based on the expected bandwidth of the stator flux linkage observer.

[0027] The stator flux linkage observer shown in equation (2) is applicable to all types of AC motors. For permanent magnet synchronous motors, the rotor flux linkage amplitude is the rotor permanent magnet flux linkage amplitude; for electrically excited synchronous motors, the rotor flux linkage amplitude is the rotor winding electrically excited flux linkage amplitude; for hybrid excited synchronous motors, the rotor flux linkage amplitude is the sum of the rotor permanent magnet flux linkage amplitude and the rotor winding electrically excited flux linkage amplitude; for induction motors and synchronous reluctance motors, the rotor flux linkage amplitude is equal to the stator-side electrically excited flux linkage amplitude after low-pass filtering. Additionally, for induction motors, the direct-axis stator inductance of the synchronous motor in equation (2) is... L d Simply replace it with the stator leakage inductance of an induction motor.

[0028] When the actual motor position angle ​ Compared with the observed motor position angle ​ e When a deviation exists, the mathematical relationship between the rotor flux amplitude and the observed stator flux is as follows: (3) In equation (3),L d This refers to the direct-axis stator inductance of a synchronous motor. L q This represents the quadrature-axis stator inductance of a synchronous motor. cos and sin represent the cosine and sine functions, respectively.

[0029] Conventional sensorless control methods further utilize the approximate relationship shown in equation (4) to extract the rotor position estimation error, which is defined as: e The rotor position estimation error can be obtained. e The approximate expression for is shown in equation (5).

[0030] (4) (5) After obtaining the rotor position estimation error e After obtaining the approximate expression, the position of the motor can be observed using the phase-locked loop shown in equation (6).

[0031] (6) In equation (6), ​ and ​ These are the proportional coefficient and integral coefficient of the phase-locked loop, respectively.

[0032] Depend on ​ It can be seen that this approximation of the rotor position estimation error will cause the flux linkage observer to converge to three equilibrium points, namely (0,0), (±), and (±). π The approximation is such that only the equilibrium point (0,0) is the desired equilibrium point. Therefore, this kind of approximation may cause the observer to converge to an undesirable equilibrium point under extreme conditions such as motor parameter mismatch, direct overspeed start, sudden acceleration and deceleration, and sudden load increase and decrease, resulting in incorrect observation of the motor rotor position.

[0033] Actual motor position angle ​ Compared with the observed motor position angle ​ e The deviation is denoted as Δ ​ Equation (3) can be rewritten as equation (7): (7) In equation (7), ​ dvr and ​ qvr These are the direct-axis flux linkage projection and the quadrature-axis flux linkage projection, respectively, formed by modulating the rotor flux linkage amplitude with the rotor position estimation error. Combined with... ​ It can be seen that when the magnetic flux observer begins to deviate from the desired equilibrium point (0,0), regardless of whether the deviation starts from the desired equilibrium point (0,0) and ends at (… π(0, 0), or shift from the expected equilibrium point (0, 0) to (- π ,0), direct-axis magnetic flux projection ​ dvr All show a decreasing trend, therefore, it can be calculated based on the direct-axis flux linkage projection. ​ dvr This is to enable the prediction of the observer's equilibrium point shift phenomenon.

[0034] (8) In equation (8), g infer This is the observer equilibrium point offset correction amount. ​ As the attenuation factor, ​ As a positive motivating factor, ​ It is a negative motivating factor. (By...) ​ It can be seen that during the shift of the observer's equilibrium point, the rotor position estimation error... e With cross-axis magnetic flux projection ​ qvr They intersect at ±45 degrees, therefore the attenuation factor ​ The upper limit is 0.707, and the attenuation factor is... ​ The lower limit is 0, which can be achieved by selecting an appropriate attenuation factor. ​ It can accurately predict the trend of the observer's equilibrium point shift. If the effects of motor parameter variations and control system sampling accuracy are considered, the attenuation factor can be adjusted. ​ The upper limit is limited to 0.5. Furthermore, this example uses the most common control strategy for AC motors, specifically the vector control strategy, where the positive excitation factor... ​ The minimum value is 1, which is the positive excitation factor. ​ The maximum value is the ratio of the current loop bandwidth to the phase-locked loop bandwidth; negative excitation factor. ​ The minimum value is 2, which is the negative incentive factor. ​ The maximum value is the ratio of the current loop bandwidth to the phase-locked loop bandwidth. Limiting the maximum values ​​of the positive and negative excitation factors is to suppress the impact of control system sampling noise on rotor position observation performance. Furthermore, the positive and negative excitation factors can be obtained either through offline debugging or based on direct-axis flux linkage projection. ​ dvr and ​ r The absolute value of the difference is combined with the upper and lower limits of the positive and negative incentive factors for online adjustment. The online adjustment rule is as follows: ​ dvr and ​ r The larger the absolute value of the difference, the larger the positive and negative incentive factors. ​ dvr and ​ rThe smaller the absolute value of the difference, the smaller the positive and negative incentive factors.

[0035] From equation (8), it can be seen that when the direct-axis magnetic flux projection... ​ dvr Greater than or equal to ​ r This means that the equilibrium point is currently within the interval converging towards the desired equilibrium point, at which point an appropriate positive excitation factor can be applied. ​ To accelerate the convergence rate of the observer to the desired equilibrium point; when the direct-axis flux linkage is projected... ​ dvr Less than ​ r This means that the equilibrium point is currently shifting towards an undesirable equilibrium point, and an appropriate counter-stimulation factor needs to be applied. ​ This is used to correct the offset of the observer's equilibrium point. Therefore, the corrected rotor position estimation error can be obtained as: (9) In equation (9), e corr The corrected rotor position estimation error is given. Combining equation (9), equation (6) can be rewritten as equation (10) to obtain the new rotor position observation expression: (10) This application also provides an AC motor rotor position observation device, which includes a real-time information acquisition module, a stator flux linkage observer construction module, an observation value acquisition module, a projection information acquisition module, a correction quantity acquisition module, an error acquisition module, and a position observation value acquisition module. The real-time information acquisition module is used to acquire real-time information about AC motors; The stator flux linkage observer building module is used to build stator flux linkage observers; The observation acquisition module is used to acquire stator flux observation values ​​based on the real-time information of the AC motor and the stator flux observer; The projection information acquisition module is used to obtain the direct-axis flux linkage projection and the quadrature-axis flux linkage projection based on the acquired stator flux linkage observation values; The correction amount acquisition module is used to predict the observer equilibrium point offset phenomenon based on the direct-axis magnetic flux projection, thereby obtaining the observer equilibrium point offset correction amount. The error acquisition module is used to obtain the rotor position estimation error based on the observer equilibrium point offset correction and the cross-axis flux projection; The position observation acquisition module is used to obtain the final rotor position observation based on the rotor position estimation error.

[0036] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for observing the rotor position of an AC motor, characterized in that, The method for observing the rotor position of the AC motor includes: Obtain real-time information about AC motors; Construct a stator flux linkage observer; The stator flux linkage observation value is obtained based on the real-time information of the AC motor and the stator flux linkage observer. The direct-axis flux linkage projection and the quadrature-axis flux linkage projection are obtained based on the stator flux linkage observation values. The observer equilibrium point offset phenomenon is predicted based on the direct-axis magnetic flux projection, thereby obtaining the observer equilibrium point offset correction amount; The rotor position estimation error is obtained based on the observer's equilibrium point offset correction and the cross-axis flux projection. The final rotor position observation value is obtained based on the rotor position estimation error; The prediction of the observer's equilibrium point offset phenomenon based on the direct-axis flux linkage projection, thereby obtaining the observer's equilibrium point offset correction amount, is obtained through the following formula: ； in; g infer This is the observer equilibrium point offset correction amount. δ As the attenuation factor, λ As a positive motivating factor, η It is a negative motivating factor; ψ dvr for The direct-axis flux projection formed by modulating the rotor flux amplitude with rotor position estimation error; ψ r It is the rotor flux linkage amplitude; The rotor position estimation error, obtained from the observer equilibrium point offset correction and the quadrature-axis flux projection, is calculated using the following formula: ； in, e corr The error is estimated for the corrected rotor position; g infer This is the observer equilibrium point offset correction amount. ψ qvr The quadrature-axis flux projection is formed by modulating the rotor flux amplitude with rotor position estimation error. ψ r It is the rotor flux linkage amplitude.

2. The AC motor rotor position observation method as described in claim 1, characterized in that, The formula for the stator flux linkage observer is as follows: ； in, ψ dv These are observations of the direct-axis stator flux linkage; ψ qv These are observations of the cross-axis stator flux linkage; θ e The observed value of the motor position angle; ψ r It is the rotor flux linkage amplitude. L d For the direct-axis stator inductance of a synchronous motor; k d It is the observation gain of the direct-axis stator flux linkage; k q It is the observation gain of the cross-axis stator flux linkage; i d It is the direct-axis stator current; i q It is the quadrature-axis stator current; d For differential operators, dt Represents the derivative with respect to time; u d It is the direct-axis stator voltage; u q It is the quadrature-axis stator voltage; R For stator resistance, θ This is the motor position angle.

3. The AC motor rotor position observation method as described in claim 2, characterized in that, The direct-axis flux linkage projection and quadrature-axis flux linkage projection obtained from the stator flux linkage observations are obtained by the following formula: ； in, ψ dvr for The direct-axis flux projection formed by modulating the rotor flux amplitude with rotor position estimation error; ψ qvr The quadrature-axis flux projection is formed by modulating the rotor flux amplitude with rotor position estimation error. θ This is the actual motor position angle; ψ r It is the rotor flux linkage amplitude; ψ dv yes Direct-axis stator flux linkage observations; ψ qv These are observations of the cross-axis stator flux linkage; L d For the direct-axis stator inductance of a synchronous motor; i d It is the direct-axis stator current; i q It is the quadrature-axis stator current; L q For the quadrature shaft stator inductance of a synchronous motor; Δθ Actual motor position angle θ Compared with the observed motor position angle θ e The deviation.

4. The method for observing the rotor position of an AC motor as described in claim 3, characterized in that, The final rotor position observation value is obtained based on the rotor position estimation error using the following formula: ； in, e corr The error is estimated for the corrected rotor position; dt Represents the derivative with respect to time; kp The proportional coefficient of the phase-locked loop; ki The integral coefficients of the phase-locked loop; This represents the final rotor position observation.

5. The AC motor rotor position observation method as described in claim 4, characterized in that, The attenuation factor δ The upper limit is 0.707, and the attenuation factor is... δ The lower limit is 0.

6. The AC motor rotor position observation method as described in claim 5, characterized in that, The attenuation factor δ The upper limit is 0.

5.

7. An AC motor rotor position observation device, characterized in that, The AC motor rotor position observation device includes: Real-time information acquisition module, the real-time information acquisition module is used to acquire real-time information of AC motor; A stator flux linkage observer construction module, which is used to construct a stator flux linkage observer; An observation acquisition module is used to acquire stator flux linkage observation values ​​based on the real-time information of the AC motor and the stator flux linkage observer. The projection information acquisition module is used to acquire the direct-axis flux linkage projection and the quadrature-axis flux linkage projection based on the acquired stator flux linkage observation values. The correction amount acquisition module is used to predict the observer equilibrium point offset phenomenon based on the direct axis magnetic flux projection, thereby obtaining the observer equilibrium point offset correction amount. An error acquisition module is used to acquire the rotor position estimation error based on the observer balance point offset correction and the cross-axis flux projection. A position observation acquisition module, which is used to acquire the final rotor position observation based on the rotor position estimation error; The prediction of the observer's equilibrium point offset phenomenon based on the direct-axis flux linkage projection, thereby obtaining the observer's equilibrium point offset correction amount, is obtained through the following formula: ； in; g infer This is the observer equilibrium point offset correction amount. δ As the attenuation factor, λ As a positive motivating factor, η It is a negative motivating factor; ψ dvr for The direct-axis flux projection formed by modulating the rotor flux amplitude with rotor position estimation error; ψ r It is the rotor flux linkage amplitude; The rotor position estimation error, obtained from the observer equilibrium point offset correction and the quadrature-axis flux projection, is calculated using the following formula: ； in, e corr The error is estimated for the corrected rotor position; g infer This is the observer equilibrium point offset correction amount. ψ qvr The quadrature-axis flux projection is formed by modulating the rotor flux amplitude with rotor position estimation error. ψ r It is the rotor flux linkage amplitude.

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