阅读说明：本技术 一种基于同步锁相的无刷直流电机换相误差提取方法 (Brushless direct current motor commutation error extraction method based on synchronous phase locking ) 是由 张海峰 李海涛 毛琨 陈宝栋 金浩 郑世强 于 2020-12-31 设计创作，主要内容包括：本发明公开了一种基于同步锁相的无刷直流电机换相误差提取方法,属于永磁电机控制的技术领域。该发明的换相误差提取方法主要包括电流积分及磁链观测器、双二阶广义积分-正序提取器和换相误差提取器等部分。首先通过坐标变换将采集的无刷直流电机的相电压和相电流转换到α-β坐标系,并利用电流积分及磁链观测器获得电流的积分及磁链；其次利用双二阶广义积分-正序提取器抑制电流和磁链中的直流分量和高次谐波成分并提取正序分量；然后使用换相误差提取器获得脉冲形式的换相误差；最后通过低通滤波器对脉冲形式的换相误差进行平滑,并进行PI控制获得无刷直流电机的换相误差。本发明的基于同步锁相的无刷直流电机换相误差提取方法可以实现对换相误差的提取,该方法具有检测精度高、抗干扰能力强等优点。(The invention discloses a brushless direct current motor commutation error extraction method based on a synchronous phase lock, and belongs to the technical field of permanent magnet motor control. The commutation error extraction method mainly comprises a current integration and flux linkage observer, a biquad generalized integration-positive sequence extractor, a commutation error extractor and the like. Firstly, converting collected phase voltage and phase current of the brushless direct current motor into an alpha-beta coordinate system through coordinate transformation, and obtaining current integral and flux linkage by using a current integral and flux linkage observer; secondly, a biquadratic generalized integral-positive sequence extractor is utilized to inhibit direct-current components and higher harmonic components in current and flux linkage and extract a positive sequence component; then, a commutation error extractor is used for obtaining a pulse-form commutation error; and finally, smoothing the commutation error in the pulse form through a low-pass filter, and performing PI control to obtain the commutation error of the brushless direct current motor. The phase-change error extraction method of the brushless direct current motor based on the synchronous phase-lock can realize the extraction of the phase-change error, and has the advantages of high detection precision, strong anti-interference capability and the like.)

1. A brushless DC motor commutation error extraction method based on a synchronous phase lock is characterized by comprising the following steps:

step 1: converting the phase voltage and the phase current under the acquired brushless direct current motor ABC coordinate system into an alpha-beta coordinate system through coordinate transformation;

step 2: obtaining current integrals and flux linkages of an alpha axis and a beta axis under an alpha-beta coordinate system by using a current integral and flux linkage observer;

and step 3: suppressing direct current components and higher harmonic components in the current integration and flux linkage in the step 2 by using a biquadratic generalized integration-positive sequence extractor, and extracting current integration of an alpha axis and a beta axis and positive sequence components of the flux linkage under an alpha-beta coordinate system;

and 4, step 4: based on the current integrals of the alpha axis and the beta axis and the positive sequence component of the flux linkage in the alpha-beta coordinate system, based on the synchronous phase locking technology, a commutation error extractor is used for obtaining a pulse-form commutation error;

and 5: and smoothing the commutation error in the form of pulse by a low-pass filter, and performing PI control to obtain the commutation error of the brushless direct current motor.

2. The method for extracting commutation error of a brushless direct current motor based on genlock according to claim 1, wherein the coordinate transformation in step 1 takes the form of:

in the formula u_a、u_b、u_cAnd i_a、i_b、i_cPhase voltage and phase current u of A phase, B phase and C phase under ABC coordinate system_α、u_βAnd i_α、i_βThe voltage and the current of an alpha axis and a beta axis under an alpha-beta coordinate system are respectively.

3. The method as claimed in claim 1, wherein the current integration and flux linkage observer in step 2 is respectively:

in the formula, h_α、h_βAnd psi_α、ψ_βThe current integral and the flux linkage of an alpha axis and a beta axis under an alpha-beta coordinate system are respectively, and R and L are respectively the phase resistance and the phase inductance of the brushless direct current motor.

4. The method as claimed in claim 1, wherein the current integral and the positive sequence component of flux linkage in step 3 are obtained by:

first, the transfer function of the second-order generalized integrator is:

in the formula, G_d(s) and G_q(s) transfer functions of homodromous output and orthogonal output of second-order generalized integrator, k is gain coefficient, and omega_eIs the angular velocity of the motor;

then, extracting h by using a positive sequence extractor_α、h_β、ψ_α、ψ_βPositive sequence component of (a):

in the formula (I), the compound is shown in the specification,andare respectively h_α、h_β、ψ_α、ψ_βThe positive sequence component of (a).

5. The method for extracting commutation error of a brushless direct current motor based on genlock according to claim 1, wherein in step 4, the commutation error in the form of pulses is obtained by:

first, toAndthe following transformations are performed:

in the formula (I), the compound is shown in the specification,andandare respectively asAndandthe binary form of (2) is based on the principle of synchronous phase locking, and the unsigned commutation error pulse is obtained by carrying out XOR operation:

in the formula (I), the compound is shown in the specification,andunsigned commutation error pulses, alpha and beta axes respectively;

then, detectingAndandandthe edge of the phase-change unit is used for judging whether the current phase-change state is a leading phase-change state or a lagging phase-change state; when in useRespectively corresponding to the rising edge and the falling edge of0 and 1, indicating that the current commutation state is a lagging commutation; when in useRespectively corresponding to the rising edge and the falling edge of0 and 1, indicating that the current commutation state is the leading commutation;

finally, a signed commutation error pulse is given according to the current commutation state, and when the commutation state is a lagging commutation, the signed commutation error pulse is givenAndis multiplied by-1 to obtain a signed commutation error pulseAndwhen the commutation state is the advanced commutation, the method providesAndis multiplied by 1 to obtain signed alpha and beta axis commutation error pulsesAnd

6. the method for extracting commutation error of a brushless direct current motor based on genlock according to claim 1, wherein the commutation error in step 5 is obtained by:

first, pass through the following low pass filter pairAndsmoothing is carried out to obtain a smooth commutation error:

in the formula (I), the compound is shown in the specification,andthe commutation errors after smoothing of the alpha and beta axes, omega, respectively_cIs the cut-off frequency of the low-pass filter;

then, toAndand adding and adjusting through PI to obtain commutation error.

Technical Field

The invention relates to the field of motor control, in particular to a method for extracting commutation errors of a brushless direct current motor.

Background

With the development of permanent magnet materials and the reduction of price, brushless direct current motors are widely applied, are regarded as electronic control motors with the most development prospect and application prospect in the 21 st century, and play a great role in aerospace, national defense equipment, scientific instruments, medical appliances and other applications. Compared with the common brush direct current motor, the brushless direct current motor adopts electronic commutation to replace the traditional electric brush, avoids the spark generated during commutation, greatly improves the running rotating speed of the motor and prolongs the service life of the motor. The rotor position is the information necessary for electronic commutation and can be obtained by three switched hall sensors mounted 120 ° apart, and also by back emf.

A method of acquiring rotor position information by using a hall sensor and performing phase commutation is called position sensor control, and a method of acquiring rotor position information by using information such as back electromotive force without using a position sensor and performing phase commutation is called position sensorless control. In order to avoid interference and increase the reliability of position information acquisition, it is necessary to process signals using a low-pass filter, a flip-flop, or the like in the position acquisition process. In the process of processing the signals, signal lag is inevitably caused, so that the rotor position for commutation lags behind the actual rotor position, and the difference between the rotor position for commutation and the actual rotor position is called commutation error. The commutation error reduces the operating efficiency of the motor and even causes commutation failure, so the commutation error must be compensated to improve the operating efficiency and reliability of the motor.

Aiming at the problem of commutation error, two solutions are mainly provided at present. The first solution is to analyze links which may generate commutation errors, and obtain and compensate the commutation errors at different rotation speeds in a modeling manner, which is also called an open-loop compensation method. The method is simple, can realize effective estimation and compensation of most commutation errors, but has limited precision of commutation error compensation, particularly when disturbed or rotating speed changes. The second solution is to perform closed-loop control on the characteristics of signals such as phase voltage, phase current, bus current and the like of the motor to achieve the purpose of phase-change error compensation. Although the method has a large calculation amount, the method has the advantages of high compensation precision, good real-time performance and strong anti-interference capability. With the continuous development of the processing capability of the digital signal processor, more advanced signal processing and control algorithms can be applied to a motor control system, the influence of parameter change and disturbance on the system is reduced, and the running performance of the motor is greatly improved. Therefore, the second method of solving the commutation error problem by using the closed-loop control method is a trend of research.

Disclosure of Invention

The invention solves the problems: aiming at the influence of the commutation error on the operating efficiency and the reliability of the brushless direct current motor, the method for extracting the commutation error of the brushless direct current motor based on the synchronous phase locking is provided, and the commutation process of the motor can be corrected and compensated through the extracted commutation error so as to improve the operating efficiency of the motor. The commutation error extraction method mainly comprises a current integration and flux linkage observer, a biquad generalized integration-positive sequence extractor, a commutation error extractor and the like. Firstly, converting collected phase voltage and phase current of the brushless direct current motor into a coordinate system through coordinate transformation, and obtaining current integral and flux linkage by using a current integral and flux linkage observer; secondly, a biquadratic generalized integral-positive sequence extractor is utilized to inhibit direct-current components and higher harmonic components in current and flux linkage and extract a positive sequence component; then, a commutation error extractor is used for obtaining a pulse-form commutation error; and finally, smoothing the commutation error in the pulse form through a low-pass filter, and performing PI control to obtain the commutation error of the brushless direct current motor.

The technical scheme adopted by the invention is as follows: a brushless DC motor commutation error extraction method based on synchronous phase locking mainly comprises a current integral and flux linkage observer, a biquad integral-positive sequence extractor and a commutation error extractor, and comprises the following steps:

step A), converting the phase voltage and the phase current under the collected brushless direct current motor ABC coordinate system into an alpha-beta coordinate system through coordinate transformation;

step B), obtaining current integrals and flux linkages of an alpha axis and a beta axis under an alpha-beta coordinate system by using a current integral and flux linkage observer;

step C) restraining direct current components and high harmonic components in the current integration and flux linkage in the step B) by using a biquadratic generalized integration-positive sequence extractor, and extracting current integration of an alpha axis and a beta axis and positive sequence components of the flux linkage under an alpha-beta coordinate system;

step D) based on the current integrals of the alpha axis and the beta axis and the positive sequence component of the flux linkage in the alpha-beta coordinate system, based on the principle of synchronous phase locking, a commutation error extractor is used for obtaining a commutation error in a pulse form;

and E) smoothing the phase change error in the pulse form through a low-pass filter, and performing PI control to obtain the phase change error of the brushless direct current motor.

The coordinate transformation in the step A adopts the following form:

in the formula u_a、u_b、u_cAnd i_a、i_b、i_cPhase voltage and phase current u of A phase, B phase and C phase under ABC coordinate system_α、u_βAnd i_α、i_βThe voltage and the current of an alpha axis and a beta axis under an alpha-beta coordinate system respectively;

in the step B, the current integral and flux linkage observers are respectively as follows:

in the formula, h_α、h_βAnd psi_α、ψ_βThe current integral and the flux linkage of an alpha axis and a beta axis under an alpha-beta coordinate system are respectively, and R and L are respectively a phase resistance and a phase inductance of the brushless direct current motor;

the current integral and the positive sequence component of the flux linkage in the step C are obtained by the following method:

first, the transfer function of the second-order generalized integrator is:

in the formula, G_d(s) and G_q(s) transfer functions of homodromous output and orthogonal output of second-order generalized integrator, k is gain coefficient, and omega_eIs the angular velocity of the motor;

then, extracting h by using a positive sequence extractor_α、h_β、ψ_α、ψ_βPositive sequence component of (a):

in the formula (I), the compound is shown in the specification,are respectively h_α、h_β、ψ_α、ψ_βA positive sequence component of (a);

the commutation error of the pulse form in the step D is obtained by the following method:

first, toThe following transformations are performed:

in the formula (I), the compound is shown in the specification,andandare respectively asAndandthe binary form of (2) is based on the principle of synchronous phase locking, and the unsigned commutation error pulse is obtained by carrying out XOR operation:

in the formula (I), the compound is shown in the specification,andunsigned commutation error pulses, alpha and beta axes respectively;

then, detectingAndandandthe edge of the phase-change unit is used for judging whether the current phase-change state is a leading phase-change state or a lagging phase-change state; when in useRespectively corresponding to the rising edge and the falling edge of0 and 1, indicating that the current commutation state is a lagging commutation; when in useRespectively corresponding to the rising edge and the falling edge of0 and 1, indicating that the current commutation state is the leading commutation;

finally, a signed commutation error pulse is given according to the current commutation state, and when the commutation state is a lagging commutation, the signed commutation error pulse is givenAndis multiplied by-1 to obtain a signed commutation error pulseAndwhen the commutation state is the advanced commutation, the method providesAndis multiplied by 1 to obtain signed alpha and beta axis commutation error pulsesAnd

the commutation error in the step E is obtained by:

first pass through the following low pass filter pairAndsmoothing is carried out to obtain a smooth commutation error:

in the formula (I), the compound is shown in the specification,andthe commutation errors after smoothing of the alpha and beta axes, omega, respectively_cIs the cut-off frequency of the low-pass filter;

then toAndand adding and adjusting through PI to obtain commutation error.

The beneficial effects brought by the invention can be embodied in the following aspects:

(1) the double-second-order generalized integral-positive sequence extractor can inhibit the direct current bias and the higher harmonic component of current integral and flux linkage and extract the positive sequence component of the direct current bias and the higher harmonic component, and reduces the influence of non-ideal factors introduced in the process of back electromotive force asymmetry and signal processing on the extraction precision of a commutation error.

(2) The commutation error extractor can extract the commutation error pulse by adopting simple XOR operation according to the current integral and the flux linkage, and obtains the signed commutation error pulse by utilizing the methods of edge detection and amplitude judgment according to the phase relation of two signals, thereby realizing the distinction of leading commutation and lagging commutation and being convenient for determining the sign of a compensation angle.

(3) The commutation error extraction method is based on the principles of current integration and flux linkage synchronous phase locking, so that the problem of current lag caused by inductance is fundamentally eliminated, and the detection precision is improved.

Drawings

FIG. 1 is a schematic block diagram of a phase-change error extraction method for a brushless DC motor based on genlock according to the present invention;

FIG. 2 is a schematic block diagram of a current integration and flux linkage observer according to the present invention;

FIG. 3 is a schematic block diagram of a second order generalized integrator in accordance with the present invention;

FIG. 4 is a schematic block diagram of a biquad generalized integral-positive sequence extractor of the present invention;

fig. 5 is a schematic block diagram of a commutation error extractor of the present invention.

Detailed Description

The technical solution of the present invention is further described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the commutation error extraction method of the brushless dc motor based on the genlock of the present invention includes a coordinate transformation part 1, current integration and flux linkage observer parts 2 and 3, biquad generalized integration-positive sequence extractor parts 4 and 5, commutation error extractor parts 6 and 7, low pass filter parts 8 and 9, and a PI control part 10.

In a specific implementation, the method for extracting the commutation error of the brushless dc motor based on the genlock comprises the following steps:

step A), converting the phase voltage and the phase current under the collected brushless direct current motor ABC coordinate system into an alpha-beta coordinate system through coordinate transformation;

step B), obtaining current integrals and flux linkages of an alpha axis and a beta axis under an alpha-beta coordinate system by using a current integral and flux linkage observer;

step C) restraining direct current components and high harmonic components in the current integration and flux linkage in the step B) by using a biquadratic generalized integration-positive sequence extractor, and extracting current integration of an alpha axis and a beta axis and positive sequence components of the flux linkage under an alpha-beta coordinate system;

step D) based on the current integrals of the alpha axis and the beta axis and the positive sequence component of the flux linkage in the alpha-beta coordinate system, based on the principle of synchronous phase locking, a commutation error extractor is used for obtaining a commutation error in a pulse form;

and E) smoothing the phase change error in the pulse form through a low-pass filter, and performing PI control to obtain the phase change error of the brushless direct current motor.

The coordinate transformation in the step A adopts the following form:

in the formula u_a、u_b、u_cAnd i_a、i_b、i_cPhase voltage and phase current u of A phase, B phase and C phase under ABC coordinate system_α、u_βAnd i_α、i_βThe voltage and the current of an alpha axis and a beta axis under an alpha-beta coordinate system respectively;

as shown in fig. 2, the current integration and flux linkage observer in step B are respectively:

in the formula, h_α、h_βAnd psi_α、ψ_βThe current integral and the flux linkage of an alpha axis and a beta axis under an alpha-beta coordinate system are respectively, and R and L are respectively a phase resistance and a phase inductance of the brushless direct current motor;

as shown in fig. 3 and 4, the positive sequence component of the current integral and the flux linkage in step C is obtained by:

first, the transfer function of the second-order generalized integrator is:

in the formula, G_d(s) and G_q(s) transfer functions of homodromous output and orthogonal output of second-order generalized integrator, k is gain coefficient, and omega_eIs the angular velocity of the motor;

then, extracting h by using a positive sequence extractor_α、h_β、ψ_α、ψ_βPositive sequence component of (a):

in the formula (I), the compound is shown in the specification,andare respectively h_α、h_β、ψ_α、ψ_βA positive sequence component of (a);

as shown in fig. 5, the commutation error in the form of pulses in step D is obtained by:

first, toAndthe following transformations are performed:

in the formula (I), the compound is shown in the specification,andandare respectively asAndandof binary form, based on genlockPrinciple, carrying out exclusive or operation to obtain unsigned commutation error pulse:

in the formula (I), the compound is shown in the specification,andunsigned commutation error pulses, alpha and beta axes respectively;

then, detectingAndandandthe edge of the phase-change unit is used for judging whether the current phase-change state is a leading phase-change state or a lagging phase-change state; when in useRespectively corresponding to the rising edge and the falling edge of0 and 1, indicating that the current commutation state is a lagging commutation; when in useRespectively corresponding to the rising edge and the falling edge of0 and 1, indicating that the current commutation state is the leading commutation;

finally, a signed commutation error pulse is given according to the current commutation state, and when the commutation state is a lagging commutation, the signed commutation error pulse is givenAndis multiplied by-1 to obtain a signed commutation error pulseAndwhen the commutation state is the advanced commutation, the method providesAndis multiplied by 1 to obtain signed alpha and beta axis commutation error pulsesAnd

the commutation error in the step E is obtained by:

first pass through the following low pass filter pairAndsmoothing is carried out to obtain a smooth commutation error:

in the formula (I), the compound is shown in the specification,andthe commutation errors after smoothing of the alpha and beta axes, omega, respectively_cIs the cut-off frequency of the low-pass filter;

then toAndand adding and adjusting through PI to obtain commutation error.

The invention has not been described in detail and is within the skill of the art.