阅读说明：本技术 基于电流偏置的永磁同步电机转子位置检测系统及方法 (Permanent magnet synchronous motor rotor position detection system and method based on current bias ) 是由 闫春幸 魏海峰 张懿 王浩陈 于 2020-11-20 设计创作，主要内容包括：本发明公开了一种基于电流偏置的永磁同步电机转子位置检测系统及方法,涉及永磁同步电机控制领域,其中检测方法包括：步骤1：建立d-q坐标系,在d-q坐标系的基础上,以旋转变压器获得的转子位置为d′轴,超前d′轴90°为q′轴,建立d′-q′旋转坐标系；步骤2：在步骤1的d′-q′坐标系基础上,给一个固定电流值,然后分解成i′-d、i′-q,令i′-d＝0时,记录i′-q,多次测量i′-q取平均值；令i′-q＝0时,记录i′-d,多次测量i′-d取平均值；步骤3：计算旋转变压器获得的转子位置与实际转子位置存在的偏差值θ；步骤4：把偏差值θ补偿给旋转变压器测得的转子位置值,完成位置检测。采用基于电流偏置的永磁同步电机转子位置检测方法,可以获得更加准确的转子位置,提高永磁同步电机起动的平滑度。(The invention discloses a current bias-based permanent magnet synchronous motor rotor position detection system and method, and relates to the field of permanent magnet synchronous motor control, wherein the detection method comprises the following steps: step 1: establishing a d-q coordinate system, and establishing a d ' -q ' rotating coordinate system by taking the rotor position obtained by a rotary transformer as a d ' axis and a 90-degree advanced d ' axis as a q ' axis on the basis of the d-q coordinate system; step 2: giving a fixed current value on the basis of the d ' -q ' coordinate system of the step 1, and then decomposing into i ' d 、i′ q Of l' d When 0, record i' q Measuring i 'a plurality of times' q Taking an average value; ream i' q When 0, record i' d Measuring i 'a plurality of times' d Taking an average value; and step 3: calculating rotor position and reality obtained for a resolverThe deviation value theta existing in the rotor position; and 4, step 4: and compensating the deviation value theta to the rotor position value measured by the rotary transformer to complete position detection. By adopting the current bias-based permanent magnet synchronous motor rotor position detection method, more accurate rotor position can be obtained, and the starting smoothness of the permanent magnet synchronous motor is improved.)

1. The method for detecting the position of the permanent magnet synchronous motor rotor based on current bias is characterized by comprising the following steps of:

step 1: establishing a d-q coordinate system, and establishing a d ' -q ' rotating coordinate system by taking the rotor position obtained by a rotary transformer as a d ' axis and a 90-degree advanced d ' axis as a q ' axis on the basis of the d-q coordinate system;

step 2: giving a fixed current value based on the d ' -q ' coordinate system of step 1, and decomposing into i '_d、i′_qOf l'_dWhen 0, record i'_qMeasuring i 'a plurality of times'_qTaking an average value; ream i'_qWhen 0, record i'_dMeasuring i 'a plurality of times'_dTaking an average value;

and step 3: calculating a deviation value theta between the rotor position obtained by the rotary transformer and the actual rotor position;

and 4, step 4: and compensating the deviation value theta to the rotor position value measured by the rotary transformer to complete position detection.

2. The method for detecting the rotor position of the current bias-based permanent magnet synchronous motor according to claim 1, wherein the d ' -q ' rotating coordinate system in the step 1 is that the rotor position obtained by a resolver is taken as a d ' axis and a 90 ° lead d ' axis is taken as a q ' axis.

3. The method for detecting the rotor position of the permanent magnet synchronous motor based on the current bias as claimed in claim 1, wherein the specific method in the step 3 is as follows:

when the load torque of the motor is constant, the deviation angle theta between the rotor position obtained by the rotary transformer and the actual rotor position can be used'_d、i_q' the concrete representation method is as follows:

wherein, 'i'_d、i′_q"is the current vector of the orthogonal and the direct axis under the d '-q' coordinate system," θ "is the position deviation angle between the rotor position obtained by the resolver and the actual rotor position.

4. The method as claimed in claim 1, wherein the angle θ between the rotor position measured by the resolver and the actual rotor position is calculated by a current vector, and the θ value is compensated to the rotor position value measured by the resolver to obtain a more accurate actual rotor position.

5. The method for detecting the rotor position of the current bias-based permanent magnet synchronous motor according to claim 1, wherein a fixed current value is given in the step 2, and the fixed value ranges from-50 to-20.

6. Permanent magnet synchronous motor rotor position detection system based on current bias, its characterized in that includes: the device comprises a d-q coordinate system unit, a current loop PI regulator unit, a reverse Park conversion unit, a space vector pulse width modulation unit, an inverter unit, a Clark conversion unit, a Park conversion unit and a rotary transformer unit;

the d-q coordinate system unit is respectively connected with the current loop PI regulator unit and the inverse Park conversion unit and is used for converting alternating-axis and direct-axis currents into alternating-axis and direct-axis voltages under a two-phase static coordinate system; the inverse Park conversion unit is respectively connected with the space vector pulse width modulation unit and the inverter unit and is used for generating PWM (pulse width modulation) waves for alternating-axis and direct-axis voltage vectors under a two-phase static coordinate system, and converting current into three-phase alternating current through the inverter; the inverter unit is respectively connected with the Clark conversion unit and the Park conversion unit and is used for converting three-phase alternating current into alternating current and direct current under two-phase synchronous rotating coordinates, then the alternating current and the direct current under the two-phase synchronous rotating coordinates can express a deviation angle theta, and finally the deviation angle theta is compensated for a rotor position value measured by the rotary transformer unit, so that a more accurate rotor position is obtained, and detection is completed.

Technical Field

The invention relates to the field of permanent magnet synchronous motor control, in particular to a permanent magnet synchronous motor rotor position detection system and method based on current bias.

Background

The permanent magnet synchronous motor has the characteristics of high performance, simple structure, high working efficiency, excellent control characteristic, high reliability and the like, and is widely applied to various industrial fields.

The position deviation of a rotor of a permanent magnet synchronous motor exists before the permanent magnet synchronous motor is started, and the problem is solved by adopting a method with a position sensor and a method without the position sensor, but when the method without the position sensor is adopted, errors can occur in a design algorithm, when the method with the position sensor is adopted, errors can occur when the position sensor is installed manually, and the position deviation of the rotor always exists in the operation process of the motor, so that the position of the rotor can not be accurately obtained in the operation of the motor, if the starting current is too large, the overcurrent or the reverse rotation of the motor can be caused, and the situation is more serious when the load is larger. Even if the rotor position deviation is small, the motor can be started, and the control performance of the motor is influenced.

The invention adopts a vector current bias method, utilizes the relation of included angles of direct and alternating current, provides a method capable of accurately measuring the position of the rotor of the permanent magnet synchronous motor, and improves the accuracy of detecting the position of the rotor.

Disclosure of Invention

The invention provides a current bias-based permanent magnet synchronous motor rotor position detection system and method, and aims to solve the problem that the rotor position cannot be accurately obtained before a motor is started.

The invention provides a current bias-based permanent magnet synchronous motor rotor position detection method, which is characterized by comprising the following steps of:

step 1: establishing a d-q coordinate system, and establishing a d ' -q ' rotating coordinate system by taking the rotor position obtained by a rotary transformer as a d ' axis and a 90-degree advanced d ' axis as a q ' axis on the basis of the d-q coordinate system;

step 2: d '-q' in step 1On the basis of the standard system, a fixed current value is given and then decomposed into i'_d、i′_qOf l'_dWhen 0, record i'_qMeasuring i 'a plurality of times'_qTaking an average value; ream i'_qWhen 0, record i'_dMeasuring i 'a plurality of times'_dTaking an average value;

and step 3: calculating a deviation value theta between the rotor position obtained by the rotary transformer and the actual rotor position;

and 4, step 4: and compensating the deviation value theta to the rotor position value measured by the rotary transformer to complete the rotor position detection.

Optionally, in step 2, a d ' -q ' coordinate system is established with the rotor position obtained by the resolver as a d ' axis and the d ' axis 90 ° ahead of the q ' axis, and assuming that the position deviation angle existing between the rotor position obtained by the resolver and the actual rotor position is θ, the voltage equation of the permanent magnet synchronous motor in the d ' -q ' coordinate system may be expressed as:

wherein, ' U ' is '_d、U′_q"is the voltage vector of the quadrature axis and the direct axis in the d ' -q ' coordinate system," i '_d、i′_q"is the current vector of the quadrature axis and the direct axis in the d ' -q ' coordinate system," ψ '_d、ψ′_q"is the orthogonal and the orthoaxial flux linkage under the d '-q' coordinate system;

the position deviation angle between the rotor position obtained by the rotary transformer and the actual rotor position is set as theta, and the flux linkage equation under the d '-q' coordinate system can be decomposed according to the position deviation angle theta as follows:

wherein, 'L'_d、L′_q"is inductance of quadrature and direct axes in d ' -q ' coordinate system," i '_d、i′_q"is the orthogonal and the orthogonal axes of the d '-q' coordinate system"ψ" is the motor flux linkage;

the electromagnetic torque equation of the permanent magnet synchronous motor under a d '-q' coordinate system is as follows:

T′_em＝p_n(ψ′_di′_q-ψ′_qi′_d)

wherein "p" is_nIs magnetic logarithm, 'psi'_d、ψ′_q"is a d ' -q ' coordinate system lower quadrature and direct axis magnetic linkage," i '_d、i′_q"is the current vector of the orthogonal and the direct axis under the d '-q' coordinate system;

substituting a flux linkage equation of the permanent magnet synchronous motor under a d '-q' coordinate system into an electromagnetic torque equation of the permanent magnet synchronous motor under the d '-q' coordinate system to obtain a new electromagnetic torque equation:

T′_em＝p_nψ(i′_dsinθ+i′_q cosθ)

wherein "p" is_nIs magnetic logarithm, 'i'_d、i′_q"is the current vector of the orthogonal and the direct axis under the d '-q' coordinate system," theta "is the position deviation angle between the rotor position obtained by the rotary transformer and the actual rotor position, and" psi "is the motor flux linkage;

let i 'in the new electromagnetic torque equation in the d' -q 'coordinate system'_dThe resulting electromagnetic torque equation is 0:

T′_em＝p_nψi′_q cosθ

wherein "p" is_nIs magnetic logarithm, 'i'_q"is the current vector of the direct axis under the d '-q' coordinate system," θ "is the angle of the position deviation between the rotor position obtained by the resolver and the actual rotor position," ψ "is the motor flux linkage;

let i 'in new electromagnetic torque equation under d' -q 'coordinate system'_q0 due to i'_dIf the quadrature axis current value still exists, instead of the actual full direct axis value, the available electromagnetic torque equation is:

T′_em＝p_nψi′_d cosθ

wherein "p" is_nIs magnetic logarithm, 'i'_d"is the current vector of the quadrature axis under the d '-q' coordinate system," θ "is the angle of the position deviation between the rotor position obtained by the resolver and the actual rotor position," ψ "is the motor flux linkage;

optionally, in the step 3, as long as the load torque of the motor is constant, the deviation angle θ existing between the obtained rotor position of the rotary transformer and the actual rotor position may be i'_d、i′_qThe relationship between them is expressed as:

wherein, 'i'_d、i′_q"is the current vector of the orthogonal and the direct axis under the d '-q' coordinate system," theta "is the position deviation angle between the rotor position obtained by the rotary transformer and the actual rotor position;

optionally, in the step 4, the deviation angle θ obtained in the step 3 is compensated to a rotor position value measured by the rotary transformer, so as to complete position detection;

optionally, a fixed current value is given in the step 2, and the value range of the fixed value is-50 to-20.

The invention provides a current bias-based permanent magnet synchronous motor rotor position detection system, which comprises: the device comprises a d-q coordinate system unit, a current loop PI regulator unit, a reverse Park conversion unit, a space vector pulse width modulation unit, an inverter unit, a Clark conversion unit, a Park conversion unit and a rotary transformer unit;

the d-q coordinate system unit is respectively connected with the current loop PI regulator unit and the inverse Park conversion unit and is used for converting alternating-axis and direct-axis currents into alternating-axis and direct-axis voltages under a two-phase static coordinate system; the inverse Park conversion unit is respectively connected with the space vector pulse width modulation unit and the inverter unit and is used for generating PWM (pulse width modulation) waves for alternating-axis and direct-axis voltage vectors under a two-phase static coordinate system, and converting current into three-phase alternating current through the inverter; the inverter unit is respectively connected with the Clark conversion unit and the Park conversion unit and is used for converting three-phase alternating current into alternating current and direct current under two-phase synchronous rotating coordinates, then the alternating current and the direct current under the two-phase synchronous rotating coordinates can express a deviation angle theta, and finally the deviation angle theta is compensated for a rotor position value measured by the rotary transformer unit, so that a more accurate rotor position is obtained, and detection is completed.

The invention at least comprises the following beneficial effects:

1. the invention adopts the current-biased permanent magnet synchronous motor rotor position detection method, the detected rotor position deviation angle theta is compensated to the measurement value of the rotary transformer, the accuracy of detecting the rotor position is improved, and the smoothness of starting the permanent magnet synchronous motor is improved.

2. Aiming at the traditional permanent magnet synchronous motor rotor position detection system and method, the invention adopts the current-biased permanent magnet synchronous motor rotor position detection system and method, and the method is simple and accurate and has strong operability.

Drawings

The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and not to be construed as limiting the invention in any way, and in which:

fig. 1 is a flowchart of a system and a method for detecting a rotor position of a permanent magnet synchronous motor based on current bias according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a d-q coordinate system and a d '-q' coordinate system in an embodiment of the present invention.

Fig. 3 is a diagram of a system for detecting a rotor position of a permanent magnet synchronous motor based on current bias according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, the present invention provides a current bias based system and method for detecting a rotor position of a permanent magnet synchronous motor, comprising the following steps:

step S1: establishing a d-q coordinate system, and then establishing a d '-q' rotating coordinate system on the basis of the d-q coordinate system, wherein the specific method comprises the following steps: as shown in fig. 2, the d ' -q ' coordinate system uses the rotor position obtained by the rotary transformer as the d ' axis and leads the d ' axis by 90 degrees as the q ' axis to establish a d ' -q ' rotary coordinate system;

step S2: giving a fixed current value based on the d ' -q ' coordinate system of step 1, and decomposing into i '_d、i′_qOf l'_dWhen 0, record i'_qMeasuring i 'a plurality of times'_qTaking an average value; ream i'_qWhen 0, record i'_dMeasuring i 'a plurality of times'_dTaking an average value, the specific method is as follows: in the d '-q' coordinate system shown in fig. 2, assuming that the position deviation angle between the rotor position obtained by the resolver and the actual rotor position is θ, the voltage equation of the permanent magnet synchronous motor in the d '-q' coordinate system can be expressed as:

wherein, ' U ' is '_d、U′_q"is the voltage vector of the quadrature axis and the direct axis in the d ' -q ' coordinate system," i '_d、i′_q"is the current vector of the quadrature axis and the direct axis in the d ' -q ' coordinate system," ψ '_d、ψ′_q"is the orthogonal and the orthoaxial flux linkage under the d '-q' coordinate system;

the position deviation angle between the rotor position obtained by the rotary transformer and the actual rotor position is set as theta, and the flux linkage equation under the d '-q' coordinate system can be decomposed according to the position deviation angle theta as follows:

wherein, 'L'_d、L′_q"is inductance of quadrature and direct axes in d ' -q ' coordinate system," i '_d、i′_q"is the current vector of the orthogonal and the direct axis under the d '-q' coordinate system," psi "is the motor flux linkage;

the electromagnetic torque equation of the permanent magnet synchronous motor under a d '-q' coordinate system is as follows:

T′_em＝p_n(ψ′_di′_q-ψ′_qi′_d)

wherein "p" is_nIs magnetic logarithm, 'psi'_d、ψ′_q"is a d ' -q ' coordinate system lower quadrature and direct axis magnetic linkage," i '_d、i′_q"is the current vector of the orthogonal and the direct axis under the d '-q' coordinate system;

substituting a flux linkage equation of the permanent magnet synchronous motor under a d '-q' coordinate system into an electromagnetic torque equation of the permanent magnet synchronous motor under the d '-q' coordinate system to obtain a new electromagnetic torque equation:

T′_em＝p_nψ(i′_dsinθ+i′_q cosθ)

wherein "p" is_nIs magnetic logarithm, 'i'_d、i′_q"is the current vector of the orthogonal and the direct axis under the d '-q' coordinate system," theta "is the position deviation angle between the rotor position obtained by the rotary transformer and the actual rotor position, and" psi "is the motor flux linkage;

let i 'in the new electromagnetic torque equation in the d' -q 'coordinate system'_dThe resulting electromagnetic torque equation is 0:

T′_em＝p_nψi′_q cosθ

wherein "p" is_nIs magnetic logarithm, 'i'_q"is the current vector of the direct axis under the d '-q' coordinate system," θ "is the angle of the position deviation between the rotor position obtained by the resolver and the actual rotor position," ψ "is the motor flux linkage;

let i 'in the new electromagnetic torque equation in the d' -q 'coordinate system'_q0, as in fig. 2, the d '-q' coordinate system is not the true d-p coordinate system,so i'_dInstead of the actual complete direct axis quantity, the quadrature axis current value still exists, and the obtained electromagnetic torque equation is:

T′_em＝p_nψi′_d cosθ

wherein "p" is_nIs magnetic logarithm, 'i'_d"is the current vector of the quadrature axis under the d '-q' coordinate system," θ "is the angle of the position deviation between the rotor position obtained by the resolver and the actual rotor position," ψ "is the motor flux linkage;

step S3: calculating a deviation value theta between the rotor position obtained by the rotary transformer and the actual rotor position, wherein the specific method comprises the following steps: the deviation angle theta existing between the obtained rotor position of the rotary transformer and the actual rotor position can be i 'as long as the motor load torque is constant'_d、i′_qThe relationship between them is expressed as:

wherein, 'i'_d、i′_q"is the current vector of the orthogonal and the direct axis under the d '-q' coordinate system," theta "is the position deviation angle between the rotor position obtained by the rotary transformer and the actual rotor position;

and compensating the rotor position value measured by the rotary transformer by the calculated deviation angle theta to finish position detection.

As shown in fig. 2, a d-q coordinate system is established, and on the basis of the d-q coordinate system, a d ' -q ' rotational coordinate system is established with the rotor position obtained by the resolver as a d ' axis and the rotor position 90 ° ahead of the d ' axis as a q ' axis, and the position deviation angle existing between the rotor position obtained by the resolver and the actual rotor position is set as θ.

As shown in fig. 3, a current bias-based permanent magnet synchronous motor rotor position detection system includes a d-p coordinate system unit 51, a current loop PI regulator unit 52, an inverse Park conversion unit 53, a space vector pulse width modulation unit SVPWM 54, an inverter unit 55, a Clark conversion unit 56, a Park conversion unit 57, and a rotary transformer unit 58; the concrete description is as follows:

the d-q coordinate system unit 51 is respectively connected with the current loop PI regulator unit 52 and the inverse Park transformation unit 53, and is used for transforming the alternating-axis current and the direct-axis current into alternating-axis voltage and direct-axis voltage under a two-phase static coordinate system; the inverse Park conversion unit 53 is respectively connected with the space vector pulse width modulation unit SVPWM 54 and the inverter unit 55, and is configured to generate PWM waves from the alternating-axis voltage vector and the direct-axis voltage vector under the two-phase stationary coordinate system, and convert the current into three-phase alternating current through the inverter; the inverter unit 55 is connected to the Clark conversion unit 56 and the Park conversion unit 57, respectively, and is configured to convert three-phase ac into ac and dc axis currents in two-phase synchronous rotation coordinates, and then the ac and dc axis currents in the two-phase synchronous rotation coordinates can represent the deviation angle θ, and finally compensate the deviation angle θ to the rotor position value measured by the resolver unit 58, thereby obtaining a more accurate rotor position and completing the detection.

It is obvious that those skilled in the art can obtain various effects not directly mentioned according to the respective embodiments without trouble from various structures according to the embodiments of the present invention. While embodiments of the invention have been disclosed above, it is not intended to be limited to the uses set forth in the specification and examples. It can be applied to all kinds of fields suitable for the present invention. Additional modifications will readily occur to those skilled in the art. It is therefore intended that the invention not be limited to the exact details and illustrations described and illustrated herein, but fall within the scope of the appended claims and equivalents thereof.