阅读说明：本技术 基于扩展电势观测器的永磁同步电机控制方法及装置 (Permanent magnet synchronous motor control method and device based on extended potential observer ) 是由 王磊 韦欣 杨英杰 于 2021-08-31 设计创作，主要内容包括：本发明实施例涉及一种基于扩展电势观测器的永磁同步电机控制方法及装置,用以修正考虑电机内部产生的谐波分量而引起的电机内部参数的扰动。包括以下步骤：步骤一,建立永磁同步电机d-q轴电压模型和负载转矩方程；步骤二,扩展电势估计中考虑电机谐波分量构造电压谐波方程；步骤三,建立修正位置环状态观测器模型。(The embodiment of the invention relates to a permanent magnet synchronous motor control method and device based on an extended potential observer, which are used for correcting the disturbance of internal parameters of a motor caused by considering harmonic components generated inside the motor. The method comprises the following steps: establishing a d-q axis voltage model and a load torque equation of a permanent magnet synchronous motor; step two, constructing a voltage harmonic equation by considering the harmonic component of the motor in the expanded potential estimation; and step three, establishing a correction position loop observer model.)

1. The permanent magnet synchronous motor control method and device based on the extended potential observer are characterized by comprising the following steps of:

step 1, establishing a d-q axis voltage model and a load torque equation of a permanent magnet synchronous motor;

step 2, constructing a voltage harmonic equation by considering the harmonic component of the motor in the expanded potential estimation;

and 3, establishing a correction position loop observer model.

2. The extended potential observer-based permanent magnet synchronous motor control method and device according to claim 1, wherein the specific process of step 1 is as follows:

step 1.1, establishing a voltage control model based on extended electromotive force

The d-q axis voltage control vector differential equation can be expressed as:

wherein the q axis leads the d axis by 90 DEG, i_dAnd i_qD-axis and q-axis feedback currents, U, respectively_dAnd U_qIs d-axis and q-axis stator voltage command, L_dAnd L_qAre d-axis and q-axis inductances, R is a resistance,as rotor flux amplitude, ω_eAs electrical angular velocity, Δ E, of the motor_d、ΔE_qAre the extended electromotive forces on the d-axis and q-axis.

Further, the voltage vector control equation of the permanent magnet synchronous motor is defined as:

in the formula (I), the compound is shown in the specification,

step 1.2, establishing a permanent magnet synchronous motor load torque equation

Wherein T is_LIs the load torque, J_mIs the mechanical moment of inertia, omega_mIs the mechanical angular velocity, B_mIs the coefficient of viscous friction.

3. The extended potential observer-based permanent magnet synchronous motor control method and device according to claim 1, wherein the specific process of step 2 is as follows:

considering factors such as stator slot effect, internal structural defects of the permanent magnet and the like, the distribution of electromagnetic force in the air gap of the motor is accompanied by a small amount of non-ideal order harmonics, which can also cause the generation of flux linkage harmonics of the rotor permanent magnet and stator current harmonics. Therefore, the permanent magnet flux linkage equation generated by the rotor permanent magnets in the three-phase stator winding is a space function with harmonics. In addition, the temperature rise of the motor under the long-term working condition can also bring about the disturbance of the internal parameters of the motor. Considering the above two factors, the three-phase current of the motor winding with the electrical angle difference of 120 ° contains (6i ± 1) subharmonic components, and when performing Clark and Park conversion, the d-axis and q-axis feedback currents can be expressed as follows:

wherein i_d1、i_q1Is the base current on the d-and q-axes, ω_eIs the electrical angular velocity, theta₀And the initial angle of the rotor of the permanent magnet synchronous motor is shown.

And the magnitude of the induced extension emf can be expressed as follows:

from equations (4) and (5), a mathematical expression of the extended electromotive force can be derived as shown in the following equation:

the amplitude and phase deviations of the space voltage vector are caused after considering the existence of current hysteresis in the actual operation of the permanent magnet synchronous motor. Voltage compensation is introduced to modify the voltage vector control equation, and then the modified motor voltage vector control equation is:

in combination with the above equations (2) and (6), the following equation can be obtained:

order to

WhereinIs the actual output voltage of the control system,is a voltage compensation which is a constant value during each control period.

4. The extended potential observer-based permanent magnet synchronous motor control method and device according to claim 1, wherein the specific process of step 3 is as follows:

step 3.1, establishing a torque model of the permanent magnet synchronous motor considering harmonic components

Under the condition that the air gap of the permanent magnet synchronous motor is uniformly distributed and the magnetic saturation phenomenon is neglected, the electromagnetic torque equation of the permanent magnet synchronous motor is as follows:

wherein P is the pole pair number of the pole magnet steel, T_elIs an electromagnetic torque.

The motor selected by the paper is a surface-mounted permanent magnet synchronous motor, because L_d＝L_qAnd therefore there is no reluctance torque. By using i_dIn the 0 control mode, the ratio of the rotating torque of the motor to the armature current is maximized, and the speed regulation control of the motor is easier to realize, so the formula (9) can be simplified as follows:

under actual working conditions, the q-axis current contains a large number of harmonic components. Therefore, the electromagnetic torque equation of the permanent magnet synchronous motor considering the harmonic component is expressed as:

from equations (3) and (11), the permanent magnet synchronous motor load torque equation can be expressed as:

wherein T is_LIs the load torque, J_mIs the mechanical moment of inertia, omega_mIs the mechanical angular velocity, B_mIs the coefficient of viscous friction.

Step 3.2, establishing a permanent magnet synchronous motor position ring space state equation

The differential equation for the angle and angular velocity of the motor rotor rotation during a control period is expressed as:

in the formula, t_sIndicating control system control calculation period, theta, omega_mRepresenting the angle and angular velocity of the rotor of the machine, respectively, and a is the load acceleration (whose value is approximately equal to zero, since the load torque hardly changes during each control cycle), Δ i_qThe current disturbance value omega caused by the temperature rise influence of the motor in the long-term working state_rr1、Ω_rr2To perturb the positive gain factor.

From equation (13), the spatial equation of state matrix for the position ring can be obtained as:

step 3.3, a permanent magnet synchronous motor position loop observer model can be established according to the formula (14):

step 3.4, the discrete equation of the position loop observer of the system can be expressed as:

condition observation adjustment factor l_co1、l_co2、l_co3The convergence speed of the observation error is determined by determining the coordinates of the pole of the state observer. Selecting a suitable adjustment factor l_co1、l_co2、l_co3The pole coordinate of the state error equation is positioned in the left half part of the complex plane coordinate system to ensure the stability of the state observer, and the pole is adjusted to be far away from the virtual axis, so that the convergence speed of the observation error is high, and the observation angle is quickly close to the true value.

The discretization equation of the permanent magnet synchronous motor position loop state observer obtained after the observation error is considered is as follows:

whereinRepresents the angle observation value of the (i +1) th cycle, b₁、b₂And b₃Represents the modified disturbance coefficient of the position ring,is the observed perturbation of the rotor angle,is the observed perturbation of the angular speed of the rotor,is the observed perturbation of the angular acceleration of the rotor.

5. The extended potential observer-based permanent magnet synchronous motor control method and device according to claim 1, characterized by comprising:

the stator of the permanent magnet synchronous motor unit receives the pulse width modulation waveform output by the power modulation unit and drives the rotor to rotate;

the encoder unit is used for receiving the current rotor rotation angle position information of the motor and outputting the current rotor mechanical rotation angle theta of the permanent magnet synchronous motor;

a correction position loop observer unit for observing the angle value and outputting the observed value of the angle position

A position ring resolving unit for controlling the calculation of the system position ring and correcting the observation angle value output by the position ring observer unitAs position feedback, a speed command omega is output through a proportion calculation link_ref；

A speed calculating unit for calculating the observation angle value based on the output of the correction position loop observer unitCalculating the rotation speed of the rotor and outputting a feedback angle omega of the motor rotor_m；

A speed loop resolving unit for realizing speed closed-loop control and outputting a current instruction value i_dref、i_qref；

An electrical angle conversion unit for converting the observation angle outputted from the corrected position loop observer unitConverting into an electrical angle value theta used for space vector coordinate transformation calculation of the permanent magnet synchronous motor_e；

The current sensor unit is used for converting the three-phase current output by the permanent magnet synchronous motor unit into an analog signal;

an analog-to-digital conversion unit for converting the analog signal output by the current sensor unit into a digital signal i_u、i_v、i_w；

A three-phase current space vector coordinate conversion unit for converting the digital signal i obtained by the A/D conversion unit_u、i_v、i_wAnd an electrical angle theta output from the electrical angle conversion unit_eThree-phase current space vector coordinate transformation is carried out, and d-q axis feedback current i is output_d、i_q；

A current loop resolving unit for resolving the current according to the d-q axis current instruction i_dref、i_qrefD-q axis voltage instruction U of current loop feedback link is calculated_d、U_qAnd space coordinate vector transformation is carried out to obtain a three-phase voltage output instruction value U_u、U_v、U_w；

A power modulation unit for outputting three-phase voltage output signal U_u、U_v、U_wAmplifying power, and outputting bus voltage V as amplitude_dcThe pulse width modulation waveform of the permanent magnet synchronous motor unit drives the permanent magnet synchronous motor unit to rotate.

Technical Field

The invention relates to a control method and a control device of a permanent magnet synchronous motor, in particular to a permanent magnet synchronous motor control method and a permanent magnet synchronous motor control device based on an extended potential observer.

Background

The permanent magnet synchronous motor serving as a common driving device has the advantages of simple structure, low noise, high energy density, high efficiency and the like, and is more and more widely applied to the industrial field. With the development of control technology, higher requirements are put on the control level of the permanent magnet synchronous motor.

In the actual operation process of the permanent magnet synchronous motor, the electromagnetic force distribution in the air gap of the motor is accompanied by the existence of a small amount of non-ideal order harmonics due to the stator cogging effect and the defects of the internal structure of the permanent magnet, which can also cause the generation of flux linkage harmonics and stator current harmonics of the rotor permanent magnet. In addition, the temperature rise of the motor under the condition of long-term operation can also bring about the disturbance of the internal parameters of the motor.

Disclosure of Invention

In order to solve the problems, the invention provides a permanent magnet synchronous motor control method and device based on an extended potential observer, which are used for considering the influence of current disturbance on position error during position observation and current error during current observation due to system position disturbance, correcting observation error of a position loop observer after analyzing rotor magnetic field harmonic waves, and aiming at improving control precision and response capability of a permanent magnet synchronous motor.

To achieve the above object, the present invention comprises the steps of:

step 1, establishing a d-q axis voltage model and a load torque equation of a permanent magnet synchronous motor;

step 2, constructing a voltage harmonic equation by considering the harmonic component of the motor in the expanded potential estimation;

and 3, establishing a correction position loop observer model.

Preferably, the step 1 is realized by the following method:

step 1.1, establishing a voltage control model based on extended electromotive force

The d-q axis voltage control vector differential equation can be expressed as:

wherein the q axis leads the d axis by 90 DEG, i_dAnd i_qD-axis and q-axis feedback currents, U, respectively_dAnd U_qIs d-axis and q-axis stator voltage command, L_dAnd L_qAre d-axis and q-axis inductances, R is a resistance,as rotor flux amplitude, ω_eAs electrical angular velocity, Δ E, of the motor_d、ΔE_qAre the extended electromotive forces on the d-axis and q-axis.

Further, the voltage vector control equation of the permanent magnet synchronous motor is defined as:

in the formula (I), the compound is shown in the specification,

step 1.2, establishing a permanent magnet synchronous motor load torque equation

Wherein T is_LIs the load torque, J_mIs the mechanical moment of inertia, omega_mIs the mechanical angular velocity, B_mIs the coefficient of viscous friction.

Preferably, the step 2 is realized by the following method:

considering factors such as stator slot effect, internal structural defects of the permanent magnet and the like, the distribution of electromagnetic force in the air gap of the motor is accompanied by a small amount of non-ideal order harmonics, which can also cause the generation of flux linkage harmonics of the rotor permanent magnet and stator current harmonics. Therefore, the permanent magnet flux linkage equation generated by the rotor permanent magnets in the three-phase stator winding is a space function with harmonics. In addition, the temperature rise of the motor under the long-term working condition can also bring about the disturbance of the internal parameters of the motor. Considering the above two factors, the three-phase current of the motor winding with the electrical angle difference of 120 ° contains (6i ± 1) subharmonic components, and when performing Clark and Park conversion, the d-axis and q-axis feedback currents can be expressed as follows:

wherein i_d1、i_q1Is d axisAnd base current on q-axis, ω_eIs the electrical angular velocity, theta₀And the initial angle of the rotor of the permanent magnet synchronous motor is shown.

And the magnitude of the induced extension emf can be expressed as follows:

from equations (4) and (5), a mathematical expression of the extended electromotive force can be derived as shown in the following equation:

the amplitude and phase deviations of the space voltage vector are caused after considering the existence of current hysteresis in the actual operation of the permanent magnet synchronous motor. Voltage compensation is introduced to modify the voltage vector control equation, and then the modified motor voltage vector control equation is:

in combination with the above equations (2) and (6), the following equation can be obtained:

order to

WhereinIs the actual output voltage of the control system,is a voltage compensation which is a constant value during each control period.

Preferably, the step 3 is realized by the following method:

step 3.1, establishing a torque model of the permanent magnet synchronous motor considering harmonic components

Under the condition that the air gap of the permanent magnet synchronous motor is uniformly distributed and the magnetic saturation phenomenon is neglected, the electromagnetic torque equation of the permanent magnet synchronous motor is as follows:

wherein P is the pole pair number of the pole magnet steel, T_elIs an electromagnetic torque.

The motor selected by the paper is a surface-mounted permanent magnet synchronous motor, because L_d＝L_qAnd therefore there is no reluctance torque. By using i_dIn the 0 control mode, the ratio of the rotating torque of the motor to the armature current is maximized, and the speed regulation control of the motor is easier to realize, so the formula (9) can be simplified as follows:

under actual working conditions, the q-axis current contains a large number of harmonic components. Therefore, the electromagnetic torque equation of the permanent magnet synchronous motor considering the harmonic component is expressed as:

from equations (3) and (11), the permanent magnet synchronous motor load torque equation can be expressed as:

wherein T is_LIs the load torque, J_mIs the mechanical moment of inertia, omega_mIs the mechanical angular velocity, B_mIs the coefficient of viscous friction.

Step 3.2, establishing a permanent magnet synchronous motor position ring space state equation

The differential equation for the angle and angular velocity of the motor rotor rotation during a control period is expressed as:

in the formula, t_sIndicating control system control calculation period, theta, omega_mRepresenting the angle and angular velocity of the rotor of the machine, respectively, and a is the load acceleration (whose value is approximately equal to zero, since the load torque hardly changes during each control cycle), Δ i_qThe current disturbance value omega caused by the temperature rise influence of the motor in the long-term working state_rr1、Ω_rr2To perturb the positive gain factor.

From equation (13), the spatial equation of state matrix for the position ring can be obtained as:

step 3.3, a permanent magnet synchronous motor position loop observer model can be established according to the formula (14):

step 3.4, the discrete equation of the position loop observer of the system can be expressed as:

condition observation adjustment factor l_co1、l_co2、l_co3The convergence speed of the observation error is determined by determining the coordinates of the pole of the state observer. Selecting a suitable adjustment factor l_co1、l_co2、l_co3The polar coordinates of the order state error equation lie in the complex planeThe left half part of the standard system is used for ensuring the stability of the state observer, and the pole is required to be adjusted to a position far away from the virtual axis, so that the convergence speed of the observation error is high, and the observation angle is enabled to approach the true value quickly.

The discretization equation of the permanent magnet synchronous motor position loop state observer obtained after the observation error is considered is as follows:

whereinRepresents the angle observation value of the (i +1) th cycle, b₁、b₂And b₃Represents the modified disturbance coefficient of the position ring,is the observed perturbation of the rotor angle,is the observed perturbation of the angular speed of the rotor,is the observed perturbation of the angular acceleration of the rotor.

As another aspect of the present invention, the present invention provides a method and an apparatus for controlling a permanent magnet synchronous motor based on an extended potential observer, including:

the stator of the permanent magnet synchronous motor unit receives the pulse width modulation waveform output by the power modulation unit and drives the rotor to rotate;

the encoder unit is used for receiving the current rotor rotation angle position information of the motor and outputting the current rotor mechanical rotation angle theta of the permanent magnet synchronous motor;

a correction position loop observer unit for observing the angle value and outputting the observed value of the angle position

A position ring resolving unit for controlling the calculation of the system position ring and correcting the observation angle value output by the position ring observer unitAs position feedback, a speed command omega is output through a proportion calculation link_ref；

A speed calculating unit for calculating the observation angle value based on the output of the correction position loop observer unitCalculating the rotation speed of the rotor and outputting a feedback angle omega of the motor rotor_m；

A speed loop resolving unit for realizing speed closed-loop control and outputting a current instruction value i_dref、i_qref；

An electrical angle conversion unit for converting the observation angle outputted from the corrected position loop observer unitConverting into an electrical angle value theta used for space vector coordinate transformation calculation of the permanent magnet synchronous motor_e；

The current sensor unit is used for converting the three-phase current output by the permanent magnet synchronous motor unit into an analog signal;

an analog-to-digital conversion unit for converting the analog signal output by the current sensor unit into a digital signal i_u、i_v、i_w；

A three-phase current space vector coordinate conversion unit for converting the digital signal i obtained by the A/D conversion unit_u、i_v、i_wAnd an electrical angle theta output from the electrical angle conversion unit_eThree-phase current space vector coordinate transformation is carried out, and d-q axis feedback current i is output_d、i_q；

A current loop calculating unit for calculating a current according to the d-q axis current commandi_dref、i_qrefD-q axis voltage instruction U of current loop feedback link is calculated_d、U_qAnd space coordinate vector transformation is carried out to obtain a three-phase voltage output instruction value U_u、U_v、U_w；

A power modulation unit for outputting three-phase voltage output signal U_u、U_v、U_wAmplifying power, and outputting bus voltage V as amplitude_dcThe pulse width modulation waveform of the permanent magnet synchronous motor unit drives the permanent magnet synchronous motor unit to rotate.

The invention has the beneficial effects that:

(1) the invention provides a permanent magnet synchronous motor control method and device based on an extended potential observer, and the voltage and current control model based on the permanent magnet synchronous motor effectively improves the observation precision and the response capability of the permanent magnet synchronous motor.

(2) The invention relates to a permanent magnet synchronous motor control method and device based on an extended potential observer, which are used for correcting the disturbance of internal parameters of a motor caused by considering flux linkage harmonic waves and current harmonic waves generated inside the motor.

(3) The permanent magnet synchronous motor control method and device based on the extended potential observer can effectively avoid the phenomenon of unstable motor operation caused by the installation of the observation sensor on the rotating shaft of the motor, and reduce the economic cost.

Drawings

FIG. 1 is a diagram of a state observer apparatus according to the present invention;

FIG. 2-1 is a waveform diagram of d-axis extended electromotive force and voltage harmonics of a permanent magnet synchronous motor under a trapezoidal tracking command;

2-2. Q-axis extended electromotive force and voltage harmonic waveform diagram of permanent magnet synchronous motor under trapezoidal tracking command;

FIG. 3-1 is a waveform diagram of d-axis extended electromotive force and voltage harmonics of a permanent magnet synchronous motor under a triangular tracking command;

3-2 is a waveform diagram of q-axis extended electromotive force and voltage harmonic of the permanent magnet synchronous motor under a triangular tracking command;

fig. 4-1 is a waveform diagram of d-axis extended electromotive force and voltage harmonic of the permanent magnet synchronous motor under sine and cosine tracking instructions;

fig. 4-2 is a waveform diagram of q-axis extended electromotive force and voltage harmonic of the permanent magnet synchronous motor under sine and cosine tracking instructions;

FIG. 5 is a state observation result of the permanent magnet synchronous motor under a trapezoidal tracking instruction;

FIG. 6 is a state observation result of the permanent magnet synchronous motor under a triangular tracking instruction;

fig. 7 is a state observation result of the permanent magnet synchronous motor under sine and cosine tracking instructions;

Detailed Description

The following describes a method and an apparatus for controlling a permanent magnet synchronous motor based on an extended potential observer according to the present invention in further detail with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims.

To achieve the above object of the claims, the present invention comprises the steps of:

step 1, establishing a d-q axis voltage model and a load torque equation of a permanent magnet synchronous motor;

step 2, constructing a voltage harmonic equation by considering the harmonic component of the motor in the expanded potential estimation;

and 3, establishing a correction position loop observer model.

The step 1 is realized by the following method:

step 1.1, establishing a voltage control model based on extended electromotive force

The d-q axis voltage control vector differential equation can be expressed as:

wherein the q axis leads the d axis by 90 DEG, i_dAnd i_qD-axis and q-axis feedback currents, U, respectively_dAnd U_qIs d-axis and q-axis stator voltage command, L_dAnd L_qAre d-axis and q-axis inductances, R is a resistance,as rotor flux amplitude, ω_eAs electrical angular velocity, Δ E, of the motor_d、ΔE_qAre the extended electromotive forces on the d-axis and q-axis.

Further, the voltage vector control equation of the permanent magnet synchronous motor is defined as:

in the formula (I), the compound is shown in the specification,

step 1.2, establishing a permanent magnet synchronous motor load torque equation

Wherein T is_LIs the load torque, J_mIs the mechanical moment of inertia, omega_mIs the mechanical angular velocity, B_mIs the coefficient of viscous friction.

The step 2 is realized by the following method:

considering factors such as stator slot effect, internal structural defects of the permanent magnet and the like, the distribution of electromagnetic force in the air gap of the motor is accompanied by a small amount of non-ideal order harmonics, which can also cause the generation of flux linkage harmonics of the rotor permanent magnet and stator current harmonics. Therefore, the permanent magnet flux linkage equation generated by the rotor permanent magnets in the three-phase stator winding is a space function with harmonics. In addition, the temperature rise of the motor under the long-term working condition can also bring about the disturbance of the internal parameters of the motor. Considering the above two factors, the three-phase current of the motor winding with the electrical angle difference of 120 ° contains (6i ± 1) subharmonic components, and when performing Clark and Park conversion, the d-axis and q-axis feedback currents can be expressed as follows:

wherein i_d1、i_q1Is the base current on the d-and q-axes, ω_eIs the electrical angular velocity, theta₀And the initial angle of the rotor of the permanent magnet synchronous motor is shown.

And the magnitude of the induced extension emf can be expressed as follows:

from equations (4) and (5), a mathematical expression of the extended electromotive force can be derived as shown in the following equation:

the amplitude and phase deviations of the space voltage vector are caused after considering the existence of current hysteresis in the actual operation of the permanent magnet synchronous motor. Voltage compensation is introduced to modify the voltage vector control equation, and then the modified motor voltage vector control equation is:

in combination with the above equations (2) and (6), the following equation can be obtained:

order to

WhereinIs the actual output of the control systemThe voltage is applied to the surface of the substrate,is a voltage compensation which is a constant value during each control period.

The step 3 is realized by the following method:

step 3.1, establishing a torque model of the permanent magnet synchronous motor considering harmonic components

Under the condition that the air gap of the permanent magnet synchronous motor is uniformly distributed and the magnetic saturation phenomenon is neglected, the electromagnetic torque equation of the permanent magnet synchronous motor is as follows:

wherein P is the pole pair number of the pole magnet steel, T_elIs an electromagnetic torque.

The motor selected by the paper is a surface-mounted permanent magnet synchronous motor, because L_d＝L_qAnd therefore there is no reluctance torque. By using i_dIn the 0 control mode, the ratio of the rotating torque of the motor to the armature current is maximized, and the speed regulation control of the motor is easier to realize, so the formula (9) can be simplified as follows:

under actual working conditions, the q-axis current contains a large number of harmonic components. Therefore, the electromagnetic torque equation of the permanent magnet synchronous motor considering the harmonic component is expressed as:

from equations (3) and (11), the permanent magnet synchronous motor load torque equation can be expressed as:

wherein T is_LIs the load torque, J_mIs the mechanical moment of inertia, omega_mIs the mechanical angular velocity, B_mIs the coefficient of viscous friction.

Step 3.2, establishing a permanent magnet synchronous motor position ring space state equation

The differential equation for the angle and angular velocity of the motor rotor rotation during a control period is expressed as:

in the formula, t_sIndicating control system control calculation period, theta, omega_mRepresenting the angle and angular velocity of the rotor of the machine, respectively, and a is the load acceleration (whose value is approximately equal to zero, since the load torque hardly changes during each control cycle), Δ i_qThe current disturbance value omega caused by the temperature rise influence of the motor in the long-term working state_rr1、Ω_rr2To perturb the positive gain factor.

From equation (13), the spatial equation of state matrix for the position ring can be obtained as:

step 3.3, a permanent magnet synchronous motor position loop observer model can be established according to the formula (14):

step 3.4, the discrete equation of the position loop observer of the system can be expressed as:

condition observation adjustment factor l_co1、l_co2、l_co3Relating to state observationAnd determining the coordinate of the pole of the device to determine the convergence speed of the observation error. Selecting a suitable adjustment factor l_co1、l_co2、l_co3The pole coordinate of the state error equation is positioned in the left half part of the complex plane coordinate system to ensure the stability of the state observer, and the pole is adjusted to be far away from the virtual axis, so that the convergence speed of the observation error is high, and the observation angle is quickly close to the true value.

The discretization equation of the permanent magnet synchronous motor position loop state observer obtained after the observation error is considered is as follows:

whereinRepresents the angle observation value of the (i +1) th cycle, b₁、b₂And b₃Represents the modified disturbance coefficient of the position ring,is the observed perturbation of the rotor angle,is the observed perturbation of the angular speed of the rotor,is the observed perturbation of the angular acceleration of the rotor.

Step 4, establishing a position feedback closed loop of the control system, wherein the implementation method comprises the following steps:

observing the angle obtained in the step 3As position loop feedback position, position command θ_refInputting a position closed loop, controlling a control system through a proportion link, and obtaining a speed loop speed instruction omega through position closed loop calculation_refAs shown in the following formula:

in the formula, K_pIndicating the position loop gain factor.

And 5, establishing a speed feedback closed loop of the control system, wherein the implementation method comprises the following steps:

ω_m＝(θ(i)-θ(i-1))/t_s (19)

in the formula, ω_mAnd (3) representing a feedback angular velocity value, theta is a mechanical rotation angle of a motor rotor, i represents a current calculation period, and (i-1) represents a last calculation period.

The speed ring adopts a PI controller, and omega obtained by a position ring resolving unit_refWith feedback speed value omega_mDifferencing to obtain a velocity feedback deviation omega_errAs shown in the following formula:

ω_err(i)＝ω_ref(i)-ω_m(i) (20)

feedback deviation omega according to current calculation period speed_err(i) And velocity loop integral coefficient K_miSolving for velocity error integral value omega_org(i) As shown in the following formula:

ω_org(i)＝ω_org(i-1)+ω_err(i)*K_mi (21)

according to the current calculation period speed error integral value omega_org(i) Feedback angular velocity value omega_mProportional coefficient K of sum velocity ring_mvSolving a current instruction i of a current calculation period of a q axis_qrefAs shown in the following formula:

i_qref(i)＝(ω_org(i)-ω_m(i))*K_mv*J_m/K_a (22)

in the formula, J_mIs the rotational inertia of the rotor of the motor, K_aIs the motor moment coefficient, i_dref＝0。

Step 6, establishing a current feedback closed loop of the control system, wherein the implementation method comprises the following steps:

d-axis current using PI controllerInstruction i_dref0, q-axis current command i_qrefObtaining a current feedback deviation as shown in the following formula:

according to the current calculation period current feedback deviation i_{d_err}(i)、i_{q_err}(i) And an integral coefficient K_iSolving a current integral error value i_{d_org}(i)、i_{q_org}(i) As shown in the following formula (24):

the current integral error value i of the current calculation period is obtained according to the formula_{d_org}(i)、i_{q_org}(i) Feedback current value i_d(i)、i_q(i) And a proportionality coefficient K_vSolving d-q axis control voltage U in current calculation period_d(i)、U_q(i) As shown in the following formula (25):

wherein R is the equivalent resistance of the permanent magnet synchronous motor, L_d、L_qIs a d-q axis equivalent inductance, omega, of a permanent magnet synchronous motor_eIs the electrical angular velocity of the permanent magnet synchronous motor,is the rotor flux amplitude.

Further, according to U_d(i)、U_q(i) Performing space coordinate vector transformation to output three-phase voltage output command value U_u、U_v、U_wAs shown in the following formula (26):

in the formula, theta_eIs the electrical angle of the motor rotor.

As another aspect of the present invention, the present invention provides a method and a device for controlling a permanent magnet synchronous motor based on an extended potential observer, where the observation device is shown in fig. 1 and includes:

the permanent magnet synchronous motor unit 1 is characterized in that a stator of the permanent magnet synchronous motor unit 1 receives a pulse width modulation waveform output by the power modulation unit 12 and drives a rotor to rotate;

the encoder unit 2 is used for receiving the current rotor rotation angle position information of the motor and outputting a current rotor mechanical rotation angle theta of the permanent magnet synchronous motor;

a correction position loop observer unit 3 for observing the angle value and outputting the angle position observed value

A position ring calculation unit 4 for calculating a control system position ring and correcting the observation angle value output by the position ring observer unit 3As position feedback, a speed command omega is output through a proportion calculation link_ref；

A speed calculating unit 5 for calculating the speed of the object based on the observation angle value output from the correction position loop observer unit 3Calculating the rotation speed of the rotor and outputting the feedback speed omega of the motor rotor_m；

A speed loop resolving unit 6 for realizing speed closed loop control and outputting a current instruction value i_dref、i_qref；

An electrical angle conversion unit 7 for converting the observation angle outputted from the corrected position loop observer unit 3Conversion to permanent magnet synchronous machinesElectric angle value theta used for space vector coordinate transformation calculation_eAs shown in the following formula (27):

in the formula, P is the number of pole pairs of the multi-pair-pole magnetic steel.

The current sensor unit 8 is used for converting the three-phase current output by the permanent magnet synchronous motor unit 1 into an analog signal;

an analog-to-digital conversion unit 9 for converting the analog signal output by the current sensor unit 8 into a digital signal i_u、i_v、i_w；

A three-phase current space vector coordinate conversion unit 10 for converting the digital signal i obtained by the A/D conversion unit 9_u、i_v、i_wAnd an electrical angle theta output from the electrical angle conversion unit 7_eThree-phase current space vector coordinate transformation is carried out, and d-q axis feedback current i is output_d、i_q；

A current loop resolving unit 11 for resolving the current instruction i according to the d-q axis_dref、i_qrefD-q axis voltage instruction U of current loop feedback link is calculated_d、U_qAnd space coordinate vector transformation is carried out to obtain a three-phase voltage output instruction value U_u、U_v、U_wAs shown in the following formula (28):

a power modulation unit 12 for outputting three-phase voltage output signals U_u、U_v、U_wAmplifying power, and outputting bus voltage V as amplitude_dcThe pulse width modulation waveform of (1) drives the permanent magnet synchronous motor unit to rotate.

The following observation simulation tests under different tracking instructions are carried out, and the gain coefficient K of the position loop is set_pTo 1150, the proportional gain coefficient K of the current loop_vIs 90, integral gain coefficient K_iWas 0.0011. In thatDuring test, the constant speed command t is given_s1As can be known from the observer equation of the position loop state of the permanent magnet synchronous motor after the system is modified, when the motor runs at different electrical angular speeds, the voltage control equation of the motor contains different types of harmonics, and therefore, the d-q axis extended electromotive force and the voltage harmonic waveform of the permanent magnet synchronous motor under the trapezoidal tracking command can be obtained as shown in fig. 2-1 and fig. 2-2; by giving a constant speed command t_s2The d-q axis extended electromotive force and voltage harmonic waveforms of the permanent magnet synchronous motor under the triangular tracking command are as shown in fig. 3-1 and fig. 3-2; by giving a constant speed command t_s3The d-q axis extended electromotive force and voltage harmonic waveform of the permanent magnet synchronous motor under the sine and cosine tracking instruction can be obtained as shown in fig. 4-1 and 4-2.

In order to further verify the effectiveness of the permanent magnet synchronous motor control method and device based on the extended potential observer, which are provided by the invention, a gain coefficient K of a position loop is set_pTo 1150, the proportional gain coefficient K of the current loop_vIs 90, integral gain coefficient K_i0.0011, by giving a constant speed command t in the experiment_s1＝0.0075，0，-0.0075，t_s20.0075, -0.0075, and a given sine-cosine shaped velocity command t_s3The state observation results of the permanent magnet synchronous motor under the trapezoidal tracking instruction, the triangular tracking instruction and the sine and cosine tracking instruction are respectively obtained as shown in fig. 5, 6 and 7.

As can be seen from fig. 5, 6 and 7, no matter the motor operates in the trapezoidal tracking command, the triangular tracking command or the sine and cosine tracking command, the permanent magnet synchronous motor control method and device based on the extended potential observer provided by the invention can accurately estimate the current angle value, which verifies the effectiveness of the invention.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, it is still within the scope of the present invention if they fall within the scope of the claims of the present invention and their equivalents.