Permanent magnet synchronous motor rotor position estimation method based on rotating speed feed-forward phase-locked loop

Abstract

The invention relates to the technical field of vehicle permanent magnet synchronous motor control, and particularly discloses a permanent magnet synchronous motor rotor position estimation method based on a rotating speed feed-forward phase-locked loop. Comprising the following steps: calculating a flux linkage under a k-moment two-phase static coordinate system according to a k-moment three-phase duty ratio, a k-moment bus voltage, a k-moment two-phase static coordinate system current, an effective flux linkage and q-axis inductance; calculating the electric angular velocity of the arc tangent rotor after filtering at the moment k according to the flux linkage under the two-phase static coordinate system at the moment k; and obtaining a k-1 moment rotor electrical angle of the permanent magnet synchronous motor, and calculating the k moment rotor electrical angle of the permanent magnet synchronous motor according to the flux linkage under the k moment two-phase static coordinate system, the k-1 moment rotor electrical angle and the filtered arc tangent rotor electrical angular velocity at the k moment. According to the permanent magnet synchronous motor rotor position estimation method based on the rotating speed feed-forward phase-locked loop, the estimation precision and the dynamic response capability of the rotor position can be improved when the rotating speed and the load of the motor suddenly change.

Description

Technical Field

[0001] This invention relates to the field of automotive permanent magnet synchronous motor control technology, and more specifically, to a method for estimating the rotor position of a permanent magnet synchronous motor based on a speed feedforward phase-locked loop. Background Technology

[0002] Rotor position is an important physical quantity in motor control, used for FOC control algorithms, fault diagnosis, and functional safety implementation. Accurate rotor position information is an important indicator to ensure the performance and safe operation of motor drive control. Therefore, rotor position estimation has become a key research direction.

[0003] While using position sensors to acquire the motor rotor position can provide accurate position information in real time, position sensors are expensive, which greatly increases the cost of the controller. Furthermore, position sensors are susceptible to environmental influences and may malfunction, resulting in low reliability.

[0004] Currently, common rotor position estimation methods mainly include the back EMF method, the high-frequency signal injection method, and the flux linkage method. Among these, the back EMF method is applicable to medium- and high-speed ranges, the high-frequency signal injection method is applicable to low-speed ranges, and the flux linkage method, where rotor flux linkage is nearly identical at both high and low speeds, and the observer has a higher signal-to-noise ratio and superior low-speed performance, is suitable for both low and medium-to-high speeds. Existing technologies have also proposed a sensorless control method combining a nonlinear flux linkage observer based on effective flux linkage design and a phase-locked loop (PLL), unifying the sensorless control strategy for surface-mounted and embedded motors and simplifying debugging. However, these methods are significantly affected by noise and disturbances, resulting in low-quality rotor position and speed fluctuation signals, which is detrimental to stable motor operation.

[0005] Therefore, a rotor position estimation phase-locked loop feedforward compensation method is designed to improve the accuracy and dynamic response of motor rotor position estimation and has a simple calculation method. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, this invention provides a rotor position estimation method for permanent magnet synchronous motors based on a speed-feedback phase-locked loop. By using the arctangent derivative of the calculation result of the nonlinear flux observer as the speed feedforward for the phase-locked loop calculation, and by adding a second-order Butterworth low-pass filter algorithm to the speed feedforward, the estimation accuracy and dynamic response capability of the rotor position can be improved when the motor speed and load change abruptly.

[0007] As a first aspect of the present invention, a method for estimating the rotor position of a permanent magnet synchronous motor based on a speed-feedforward phase-locked loop is provided, the method comprising the following steps: Step S1: Obtain the three-phase duty cycle of the permanent magnet synchronous motor at time k. , and Bus voltage at time k Current in the two-phase stationary coordinate system at time k and Effective magnetic flux and q-axis inductor And based on the three-phase duty cycle at time k. , and Bus voltage at time k Current in the two-phase stationary coordinate system at time k and Effective magnetic flux and q-axis inductor Calculate the flux linkage in the two-phase stationary coordinate system at time k. and ; Step S2: Based on the magnetic flux linkage in the two-phase stationary coordinate system at time k and Calculate the arctangential rotor electric angular velocity after filtering at time k. ; Step S3: Obtain the rotor electrical angle of the permanent magnet synchronous motor at time k-1. And based on the magnetic flux linkage in the two-phase stationary coordinate system at time k. and The rotor electrical angle at time k-1 and the filtered arctangential rotor electric angular velocity at time k Calculate the rotor electrical angle of the permanent magnet synchronous motor at time k. .

[0008] Further, step S1 includes: Step S11: Through The shaft voltage calculation method is based on the three-phase duty cycle at time k. , , Bus voltage at time k Calculate the voltage in the two-phase stationary coordinate system at time k. and ; wherein, the The method for calculating shaft voltage is shown in formula (1.1): (1.1), in, In the two-phase stationary coordinate system at time k shaft voltage, In the two-phase stationary coordinate system at time k Shaft voltage; Step S12: Using a nonlinear flux linkage observer, based on the voltage in the two-phase stationary coordinate system at time k... and The current in the two-phase stationary coordinate system at time k and Effective magnetic flux and q-axis inductor Calculate the flux linkage in the two-phase stationary coordinate system at time k. and The calculation formula for the nonlinear flux observer is shown in formula (1.2.1): in: (1.2.1), (1.2.2), (1.2.3), (1.2.4), (1.2.5), in, In the two-phase stationary coordinate system at time k shaft current, In the two-phase stationary coordinate system at time k shaft current, In the two-phase stationary coordinate system at time k Axial magnetic flux, In the two-phase stationary coordinate system at time k Axial magnetic flux; For state variables, To estimate state variables, To estimate state variables The first derivative with respect to time, The estimated state variables for the constructed nonlinear flux observer are: For output variables, For observer gain; It is a permanent magnet flux chain. For stator resistance, For d-axis inductance, It is the q-axis inductance. For d-axis current, Let be the rotor electrical angle at time k-1.

[0009] Further, step S2 includes: Step S21: Based on the magnetic flux linkage in the two-phase stationary coordinate system at time k and The arctangent rotor electrical angle at time k is obtained by arctangent calculation. The calculation formula is shown in formula (2.1): (2.1), Step S22: Based on the arctangent rotor electrical angle at time k The arctangential rotor electric angular velocity at time k is obtained by calculating the derivative with respect to time. The calculation formula is shown in formula (2.2): (2.2), Step S23: Based on the arctangential rotor electric angular velocity at time k The filtered arctangential rotor electric angular velocity at time k is obtained by using a second-order Butterworth low-pass filter. The transfer function of the second-order Butterworth low-pass filter is... As shown in formula (2.3): (2.3), in, This is the cutoff frequency of the second-order Butterworth low-pass filter; This is the output of the second-order Butterworth low-pass filter; This is the input of the second-order Butterworth low-pass filter; For the Laplace operator.

[0010] Further, step S3 includes: Step S31: Based on the magnetic flux linkage in the two-phase stationary coordinate system at time k , and rotor electrical angle at time k-1 The q-axis flux linkage in the two-phase moving coordinate system is obtained by calculating the Park transformation. The matrix representing the changes in park is shown in formula (3.1): (3.1), in, The d-axis flux linkage in a two-phase moving coordinate system; Step S32: Based on the q-axis flux linkage in the two-phase moving coordinate system at time k. The change in rotor electrical angular velocity at time k is calculated using a PI controller. As shown in formula (3.2): (3.2), in, The proportional coefficient of the PI controller. The integral coefficient of the PI controller; Step S33: Based on the rotor electric angular velocity change value at time k The filtered arctangential rotor electric angular velocity at time k The rotor electric angular velocity at time k is obtained by adding them together. As shown in formula (3.3): (3.3), Step S34: Based on the rotor electric angular velocity at time k The rotor electrical angle of the permanent magnet synchronous motor at time k is obtained by integral calculation. As shown in formula (3.4): (3.4), Wherein, the rotor electrical angle of the permanent magnet synchronous motor at time k is... , which is the estimated rotor position of the permanent magnet synchronous motor at time k.

[0011] The rotor position estimation method for permanent magnet synchronous motors based on speed feedforward phase-locked loops provided by this invention has the following beneficial effects: (1) Optimized speed dynamic response: This method utilizes the high responsiveness of arctangent calculation; in the process of rotor position and speed estimation, the basic speed is first obtained by differentiating the back EMF phase, and this speed is used as the feedforward of the phase-locked loop to extract the final rotor position information; (2) High speed stability: The phase-locked loop has closed-loop feedback regulation capability, which effectively reduces the system's dependence on and sensitivity to back EMF signals, and reduces harmonic pulsation of rotor position and speed; (3) Low computational load: The method has a simple structure and low computational load, which can meet the requirements of low-end chips for high dynamic response of permanent magnet synchronous motor. Attached Figure Description

[0012] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof.

[0013] Figure 1 The flowchart shows the rotor position estimation method for permanent magnet synchronous motors based on speed feedforward phase-locked loops provided by this invention.

[0014] Figure 2 The specific principle block diagram of the rotor position estimation method for permanent magnet synchronous motor based on speed feedforward phase-locked loop provided by the present invention is shown.

[0015] Figure 3 The discrete computational structure diagram of the second-order Butterworth low-pass filter provided by this invention is shown.

[0016] Figure 4 The block diagram of the application control system for the rotor position estimation method of permanent magnet synchronous motor based on speed feedforward phase-locked loop provided by the present invention. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a rotor position estimation method for a permanent magnet synchronous motor based on a speed-feedback phase-locked loop proposed according to the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0018] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] This embodiment provides a method for estimating the rotor position of a permanent magnet synchronous motor based on a speed-feedforward phase-locked loop, such as... Figure 1 As shown, the rotor position estimation method for permanent magnet synchronous motors based on speed feedforward phase-locked loops includes the following steps: Step S1: Obtain the three-phase duty cycle of the permanent magnet synchronous motor at time k. , and Bus voltage at time k Current in the two-phase stationary coordinate system at time k and Effective magnetic flux and q-axis inductor And based on the three-phase duty cycle at time k. , and Bus voltage at time k Current in the two-phase stationary coordinate system at time k and Effective magnetic flux and q-axis inductor Calculate the flux linkage in the two-phase stationary coordinate system at time k. and ; Preferably, such as Figure 2 As shown, step S1 includes: Step S11: Through The shaft voltage calculation method is based on the three-phase duty cycle at time k. , , Bus voltage at time k And the voltage in the two-phase stationary coordinate system at time k is calculated using the inverse transformation of Park. and ; wherein, the The method for calculating shaft voltage is shown in formula (1.1): (1.1), in, In the two-phase stationary coordinate system at time k shaft voltage, In the two-phase stationary coordinate system at time k Shaft voltage; Step S12: Using a nonlinear flux linkage observer, based on the voltage in the two-phase stationary coordinate system at time k... and The current in the two-phase stationary coordinate system at time k and Effective magnetic flux and q-axis inductor Calculate the flux linkage in the two-phase stationary coordinate system at time k. and The calculation formula for the nonlinear flux observer is shown in formula (1.2.1): in: (1.2.1), (1.2.2), (1.2.3), (1.2.4), (1.2.5), in, In the two-phase stationary coordinate system at time k shaft current, In the two-phase stationary coordinate system at time k shaft current, In the two-phase stationary coordinate system at time k Axial magnetic flux, In the two-phase stationary coordinate system at time k Axial magnetic flux; Define state variables. The flux linkage equation in the two-phase stationary coordinate system is shown in formula (1.2.2); To estimate state variables; To estimate state variables The first derivative with respect to time, The estimated state variables for the constructed nonlinear flux linkage observer; Define an output variable. State variables The first derivative is shown in formula (1.2.3); For observer gain, It needs to be adjusted according to the actual situation; For permanent magnet flux linkage; Stator resistance; It is the d-axis inductance; It is the q-axis inductance; This refers to the d-axis current. Let be the rotor electrical angle at time k-1.

[0020] Step S2: Based on the magnetic flux linkage in the two-phase stationary coordinate system at time k and Calculate the arctangential rotor electric angular velocity after filtering at time k. ; Preferably, such as Figure 2 As shown, step S2 includes: Step S21: Based on the magnetic flux linkage in the two-phase stationary coordinate system at time k and The arctangent rotor electrical angle at time k is obtained by arctangent calculation. The calculation formula is shown in formula (2.1): (2.1), Step S22: Based on the arctangent rotor electrical angle at time k The arctangential rotor electric angular velocity at time k is obtained by calculating the derivative with respect to time. The calculation formula is shown in formula (2.2): (2.2), Step S23: Based on the arctangential rotor electric angular velocity at time k The filtered arctangential rotor electric angular velocity at time k is obtained by using a second-order Butterworth low-pass filter. The transfer function of the second-order Butterworth low-pass filter is... As shown in formula (2.3): (2.3), in, This is the cutoff frequency of the second-order Butterworth low-pass filter; This is the output of the second-order Butterworth low-pass filter; This is the input of the second-order Butterworth low-pass filter; For the Laplace operator.

[0021] It should be noted that the arctangent rotor electric angular velocity at time k after filtering the output of the second-order Butterworth low-pass filter is... As a speed feedforward for the phase-locked loop.

[0022] Specifically, such as Figure 3 The figure shows the discrete computational structure of a second-order Butterworth low-pass filter. for Timing filter input; for Timing filter input; for Timing filter input; for Time filter output; for Time filter output; for Time filter output; These are the filter coefficients, calculated from the system parameters and the target filtering value; 1 / It acts as a delay unit, delaying the input by one time step. Therefore, the filter output at time z... for: .

[0023] Step S3: Obtain the rotor electrical angle of the permanent magnet synchronous motor at time k-1. And based on the magnetic flux linkage in the two-phase stationary coordinate system at time k. and The rotor electrical angle at time k-1 and the filtered arctangential rotor electric angular velocity at time k Calculate the rotor electrical angle of the permanent magnet synchronous motor at time k. .

[0024] Preferably, such as Figure 2 As shown, step S3 includes: Step S31: Based on the magnetic flux linkage in the two-phase stationary coordinate system at time k , and rotor electrical angle at time k-1 The q-axis flux linkage in the two-phase moving coordinate system is obtained by calculating the Park transformation. The matrix representing the changes in park is shown in formula (3.1): (3.1).

[0025] in, d-axis flux linkage in a two-phase moving coordinate system; Step S32: Based on the q-axis flux linkage in the two-phase moving coordinate system at time k. The change in rotor electrical angular velocity at time k is calculated using a PI controller. As shown in formula (3.2): (3.2), in, The proportional coefficient of the PI controller. The integral coefficient of the PI controller; Step S33: Based on the rotor electric angular velocity change value at time k The filtered arctangential rotor electric angular velocity at time k The rotor electric angular velocity at time k is obtained by adding them together. As shown in formula (3.3): (3.3), Step S34: Based on the rotor electric angular velocity at time k The rotor electrical angle of the permanent magnet synchronous motor at time k is obtained by integral calculation. As shown in formula (3.4): (3.4), Wherein, the rotor electrical angle of the permanent magnet synchronous motor at time k is... , which is the estimated rotor position of the permanent magnet synchronous motor at time k.

[0026] like Figure 4 The figure shows the application control system block diagram of the permanent magnet synchronous motor rotor position estimation method based on speed feedforward phase-locked loop provided by the present invention. (1) First, based on the given reference speed and feedback speed The difference is used to calculate the reference q-axis current through a PI controller. Then, based on the calculated reference q-axis current... and actual q-axis current And the reference d-axis current 0 and the actual d-axis current The reference d-axis voltage is calculated using two PI controllers respectively. and reference q-axis voltage Then, based on the reference d-axis voltage... and reference q-axis voltage and rotor electrical angle at time k The reference α-axis voltage is obtained through the inverse Park transformation. and reference β-axis voltage Then, based on the reference α-axis voltage... and reference β-axis voltage The three-phase duty cycle is calculated using SVPWM. , Then the three-phase duty cycle , Input to IGBT power converter; (2) Current sampling process: First, the actual three-phase current of the motor is sampled from the permanent magnet synchronous motor (PMSM) through the current sensor. Then, based on the actual three-phase current of the motor... The actual α-axis current was calculated using the Clark transform. and actual β-axis current Then, based on the actual α-axis current... and actual β-axis current The actual d-axis current is obtained by calculating the Park variation. and actual q-axis current (3) The angle and speed calculation process is based on the three-phase duty cycle. , Actual α-axis current and actual β-axis current and bus voltage The rotor electric angular velocity at time k is calculated using the "nonlinear flux observer + speed feedforward + phase-locked loop" method in this invention. and rotor electrical angle at time k .

[0027] The rotor position estimation method for permanent magnet synchronous motors based on speed feedforward phase-locked loop provided in this invention combines the arctangent derivative of the calculation result of the nonlinear flux observer with the rotor speed calculated by the speed feedforward and the phase-locked loop. The second-order Butterworth low-pass filter algorithm is incorporated into the speed feedforward, which effectively improves the dynamic response of the speed, reduces rotor position harmonic pulsation, and improves the speed and accuracy of rotor position extraction.

[0028] The rotor position estimation method for permanent magnet synchronous motors based on speed feedforward phase-locked loop provided in this invention effectively reduces the system's dependence on and sensitivity to back EMF signals, reduces harmonic pulsations in rotor position and speed, and exhibits high dynamic response.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for estimating the rotor position of a permanent magnet synchronous motor based on a speed-feedforward phase-locked loop, characterized in that, The rotor position estimation method for permanent magnet synchronous motors based on speed feedforward phase-locked loops includes the following steps: Step S1: Obtain the three-phase duty cycle of the permanent magnet synchronous motor at time k. , and Bus voltage at time k Current in the two-phase stationary coordinate system at time k and Effective magnetic flux and q-axis inductor And based on the three-phase duty cycle at time k. , and Bus voltage at time k Current in the two-phase stationary coordinate system at time k and Effective magnetic flux and q-axis inductor Calculate the flux linkage in the two-phase stationary coordinate system at time k. and ; Step S2: Based on the magnetic flux linkage in the two-phase stationary coordinate system at time k and Calculate the arctangential rotor electric angular velocity after filtering at time k. ; Step S3: Obtain the rotor electrical angle of the permanent magnet synchronous motor at time k-1. And based on the magnetic flux linkage in the two-phase stationary coordinate system at time k. and The rotor electrical angle at time k-1 and the filtered arctangential rotor electric angular velocity at time k Calculate the rotor electrical angle of the permanent magnet synchronous motor at time k. .

2. The method for estimating the rotor position of a permanent magnet synchronous motor based on a speed-feedback phase-locked loop according to claim 1, characterized in that, Step S1 includes: Step S11: Through The shaft voltage calculation method is based on the three-phase duty cycle at time k. , , Bus voltage at time k Calculate the voltage in the two-phase stationary coordinate system at time k. and ; wherein, the The method for calculating shaft voltage is shown in formula (1.1): （1.1）， in, In the two-phase stationary coordinate system at time k shaft voltage, In the two-phase stationary coordinate system at time k Shaft voltage; Step S12: Using a nonlinear flux linkage observer, based on the voltage in the two-phase stationary coordinate system at time k... and The current in the two-phase stationary coordinate system at time k and Effective magnetic flux and q-axis inductor Calculate the flux linkage in the two-phase stationary coordinate system at time k. and The calculation formula for the nonlinear flux observer is shown in formula (1.2.1): in: (1.2.1)， (1.2.2)， (1.2.3)， (1.2.4)， (1.2.5)， in, In the two-phase stationary coordinate system at time k shaft current, In the two-phase stationary coordinate system at time k shaft current, In the two-phase stationary coordinate system at time k Axial magnetic flux, In the two-phase stationary coordinate system at time k Axial magnetic flux; For state variables, To estimate state variables, To estimate state variables The first derivative with respect to time, The estimated state variables for the constructed nonlinear flux linkage observer are: For output variables, For observer gain; It is a permanent magnet flux chain. For stator resistance, For d-axis inductance, It is the q-axis inductance. For d-axis current, Let be the rotor electrical angle at time k-1.

3. The method for estimating the rotor position of a permanent magnet synchronous motor based on a speed-feedback phase-locked loop according to claim 1, characterized in that, Step S2 includes: Step S21: Based on the magnetic flux linkage in the two-phase stationary coordinate system at time k and The arctangent rotor electrical angle at time k is obtained by arctangent calculation. The calculation formula is shown in formula (2.1): （2.1）， Step S22: Based on the arctangent rotor electrical angle at time k The arctangential rotor electric angular velocity at time k is obtained by calculating the derivative with respect to time. The calculation formula is shown in formula (2.2): （2.2）， Step S23: Based on the arctangential rotor electric angular velocity at time k The filtered arctangential rotor electric angular velocity at time k is obtained by using a second-order Butterworth low-pass filter. The transfer function of the second-order Butterworth low-pass filter is... As shown in formula (2.3): （2.3）， in, This is the cutoff frequency of the second-order Butterworth low-pass filter; This is the output of the second-order Butterworth low-pass filter; This is the input of the second-order Butterworth low-pass filter; For the Laplace operator.

4. The method for estimating the rotor position of a permanent magnet synchronous motor based on a speed-feedback phase-locked loop according to claim 1, characterized in that, Step S3 includes: Step S31: Based on the magnetic flux linkage in the two-phase stationary coordinate system at time k , and rotor electrical angle at time k-1 The q-axis flux linkage in the two-phase moving coordinate system is obtained by calculating the Park transformation. The matrix representing the changes in park is shown in formula (3.1): （3.1）， in, The d-axis flux linkage in a two-phase moving coordinate system; Step S32: Based on the q-axis flux linkage in the two-phase moving coordinate system at time k. The change in rotor electrical angular velocity at time k is calculated using a PI controller. As shown in formula (3.2): （3.2）， in, The proportional coefficient of the PI controller. The integral coefficient of the PI controller; Step S33: Based on the rotor electric angular velocity change value at time k The filtered arctangential rotor electric angular velocity at time k The rotor electric angular velocity at time k is obtained by adding them together. As shown in formula (3.3): （3.3）， Step S34: Based on the rotor electric angular velocity at time k The rotor electrical angle of the permanent magnet synchronous motor at time k is obtained by integral calculation. As shown in formula (3.4): （3.4）， Wherein, the rotor electrical angle of the permanent magnet synchronous motor at time k is... , which is the estimated rotor position of the permanent magnet synchronous motor at time k.

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