阅读说明：本技术 一种基于永磁同步电机模型的电压前馈控制方法及装置 (Voltage feedforward control method and device based on permanent magnet synchronous motor model ) 是由 王磊 肖磊 潘巍 于 2020-05-25 设计创作，主要内容包括：本发明实施例涉及一种基于永磁同步电机模型的电压前馈控制方法及装置,用于提高交流伺服驱动控制系统电流环响应速度。该种电流前馈结构可以实现电流前馈指令的独立计算,不受到外界扰动的影响,充分考虑了控制系统永磁同步电机模型,提高了控制系统电流前馈指令的精度,该种新型电流前馈系统相比于传统的基于低通滤波的电流前馈系统具有更好的电流指令跟踪能力,消除了低通滤波前馈对电流指令滤波造成的失真,该方法有效提高了控制系统的电流响应跟踪能力。(The embodiment of the invention relates to a voltage feedforward control method and device based on a permanent magnet synchronous motor model, which are used for improving the current loop response speed of an alternating current servo drive control system. The current feedforward structure can realize independent calculation of the current feedforward instruction, is not influenced by external disturbance, fully considers a permanent magnet synchronous motor model of a control system, improves the precision of the current feedforward instruction of the control system, has better current instruction tracking capability compared with the traditional current feedforward system based on low-pass filtering, eliminates distortion caused by low-pass filtering feedforward to current instruction filtering, and effectively improves the current response tracking capability of the control system.)

1. A voltage feedforward control method based on a permanent magnet synchronous motor model is characterized in that: the method comprises the following steps:

(1) establishing a mathematical model of the permanent magnet synchronous motor to obtain a d-q voltage instruction output equation;

(2) carrying out space vector coordinate transformation on three-phase feedback current of the permanent magnet synchronous motor to obtain d-q axis feedback current;

(3) establishing a current loop feedback control loop;

(4) constructing a current loop feedforward control structure according to a mathematical model of the permanent magnet synchronous motor;

(5) injecting the output voltage feedforward instruction into a current loop feedback control loop to complete current loop closed-loop calculation;

(6) performing space vector coordinate transformation on the d-q axis command voltage to obtain a three-phase voltage command output value of the permanent magnet synchronous motor;

(7) and inputting the three-phase voltage command into a power amplification and modulation unit, and outputting a three-phase pulse width modulation wave with the amplitude value of the bus voltage by the power amplification and modulation unit to drive the permanent magnet synchronous motor unit to rotate.

2. The voltage feedforward control method based on the permanent magnet synchronous motor model according to claim 1, characterized in that: the step (1) is realized by the following method:

the mathematical model of the permanent magnet synchronous motor is shown as formula (1):

in the formula: u shape_d、U_qFor d-axis and q-axis stator voltage commands L_d、L_qEquivalent inductances of a d axis and a q axis; r_sIs a stator resistor; omega_eIs the electrical angular velocity;is a rotor flux linkage; i.e. i_d、i_qFeeding back currents for the d-axis stator and the q-axis stator;

the motor torque model is shown as formula (2):

in the formula: t is_eIs an electromagnetic torque; p is the number of pole pairs of the motor;

the mechanical equation of motion is shown in equation (3):

in the formula: t is₁Is the load torque; omega_mIs the mechanical angular velocity; f is the motor friction factor; j is the rotational inertia of the motor;

in order to realize the maximum torque control, a d-axis current instruction i is given_dWhen the motor torque output equation is 0, the motor torque output equation is expressed by equation (4):

3. the voltage feedforward control method based on the permanent magnet synchronous motor model according to claim 1, characterized in that: the step (2) is realized by the following method:

three-phase current is collected from three phases of the permanent magnet synchronous motor to obtain three-phase feedback phase current i_u、i_v、i_wObtaining d-q axis feedback current i through space vector coordinate change_d、i_qAs shown in formula (5):

4. the voltage feedforward control method based on the permanent magnet synchronous motor model according to claim 1, characterized in that: the step (3) is realized by the following method:

discretizing the mathematical model of the permanent magnet synchronous motor according to the mathematical model of the permanent magnet synchronous motor in the step (1), adopting a PI (proportional integral) controller to realize the calculation of a d-q axis voltage command, wherein k represents the current calculation period, k-1 represents the last calculation period, and according to the current calculation period, obtaining a current command value i_dref、i_qrefAnd the actual d-q axis current feedback value i_d、i_qObtaining a current feedback deviation i_{d_err}、i_{q_err}As shown in formula (6):

current feedback error i according to current calculation period_{d_err(k)}、i_{q_err(k)}And an integral coefficient K_iFor current error integral value i_{d_org(k)}、i_{q_org(k)}Solving is carried out as shown in equation (7):

current error integral value i obtained according to current calculation period_{d_org(k)}、i_{q_org(k)}Feedback current i_d(k)、i_q(k)And a proportionality coefficient K_vSolving the d-q axis control voltage command is shown in the formula (8):

wherein Rs is the equivalent resistance of the permanent magnet synchronous motor L_d、L_qIs the d-q axis equivalent inductance value, omega, of the permanent magnet synchronous motor_eIs the electric angle rotating speed value of the permanent magnet synchronous motor,is the equivalent flux linkage coefficient of the permanent magnet synchronous motor.

5. The voltage feedforward control method based on the permanent magnet synchronous motor model according to claim 1, characterized in that: the step (4) is realized by the following method:

adopting a PI controller to realize the calculation of a d-q axis feedforward voltage instruction, wherein k represents the current calculation period, k-1 represents the last calculation period, and taking a q axis current feedforward instruction as an example, according to the current calculation period current instruction value i_qrefQ-axis current feedback value i of current loop feedforward structure_FFFBObtaining a feedforward current feedback deviation i_{qff_err}As shown in formula (9):

i_{qff_err(k)}＝i_qref(k)-i_FFFB(k)(9)

current feedback error i according to current calculation period_{qff_err(k)}And current feedforward integral coefficient K_CiFFFor feedforward current error integral value i_{qff_org(k)}Solving is carried out as shown in equation (10):

i_{qff_org(k)}＝i_{qff_org(k-1)}+i_{qff_err(k)}*K_CiFF(10)

feedforward current error integral value i obtained according to current calculation period_{qff_org(k)}Feedback current i of feedforward closed loop_FFFB(k)And feedforward proportionality coefficient K_CvFFFeedforward control voltage U to q axis_qff(k)Solving is carried out as shown in equation (11):

U_qff(k)＝(i_{qff_org(k)}-i_FFFB(k))K_CvFFL_FF-R_FFi_FFFB(k)(11)

in the formula: r_FFL, a feedforward structural equivalent resistance of a permanent magnet synchronous motor_FFFeeding forward an equivalent inductance value for the permanent magnet synchronous motor;

for the feedforward output voltage value U of the q axis_qff(k)Limiting the amplitude value to make it not exceed the bus voltage V_dcTo obtain a final feedforward voltage command U_qffout(k)As shown in equation (12):

integrating the feedforward voltage command is shown in equation (13):

obtaining the feedback current i of the feedforward current loop through the process_FFFBThereby achieving closed loop control of the feed forward current loop.

6. The voltage feedforward control method based on the permanent magnet synchronous motor model according to claim 1, characterized in that: the step (5) is realized by the following method:

feed-forward voltage instruction U in closed loop of q-axis feed-forward current_qffoutIntroducing a current loop feedback loop, wherein the current loop q-axis voltage instruction U subjected to voltage feedforward injection_qoutAs shown in equation (14):

U_qout＝U_qffout+U_q(14)

the d-axis voltage command U can be obtained by the same method_dout。

7. The voltage feedforward control method based on the permanent magnet synchronous motor model according to claim 1, characterized in that: the step (6) is realized by the following method:

d-q axis feedback current i obtained in the step (2)_d、i_qThe d-q axis voltage command U obtained in the step (5) is substituted into a discretized d-q axis voltage control equation_dout、U_qoutSpace vector coordinate transformation is carried out to obtain three-phase voltage command U_u、U_v、U_wAs shown in equation (15):

8. the voltage feedforward control method based on the permanent magnet synchronous motor model according to claim 1, characterized in that: the step (7) is realized by the following method:

the three-phase voltage instruction U obtained in the step (6) is processed_u,v,wAnd outputting the three-phase pulse width modulation waveform to a power modulation unit for power amplification, and outputting the three-phase pulse width modulation waveform subjected to power amplification to drive the motor to rotate.

9. The device of the voltage feedforward control method based on the permanent magnet synchronous motor model is characterized by comprising the following steps:

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;

an encoder unit for measuring the current position of the rotor angle of the PMSM unit and outputting the mechanical rotor angle theta of the PMSM unit_m；

An electrical angle conversion unit for converting the mechanical rotation angle theta obtained by the encoder unit_mConversion into electrical angle theta for space vector coordinate transformation calculation of permanent magnet synchronous motor_e；

A current sensor unit 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_wThe subsequent calculation processing is convenient;

a three-phase current space vector conversion unit for converting the current digital signal i obtained by the A/D conversion unit_u、i_v、i_wAnd an electrical angle theta obtained by the electrical angle conversion unit_eThe space vector coordinate change of the three-phase current is carried out to obtain the feedback current i of the d-q axis_d、i_q；

A speed calculation unit for calculating the feedback speed omega of the rotor of the PMSM unit_mAnd feeding back the speed omega of the rotor_mConversion to electrical angle omega_e；

A current instruction unit for receiving a current instruction value i sent by the upper computer_dref、i_qref；

A voltage feedforward calculation unit for calculating a feedforward voltage command U of the control system_qffout、U_dffout；

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_qA feedforward voltage command U obtained by the voltage feedforward calculation unit_qff、U_dffAnd d-q axis voltage command U_d、U_qCombining to obtain a final d-q axis voltage command U_qout、U_doutFurther, according to U_qout、U_doutSpace vector coordinate transformation is carried out to obtain a three-phase voltage output instruction U_u、U_v、U_w；

A power modulation unit for outputting three-phase voltage output signal U_u,v,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 mainly aims at the control process of a permanent magnet synchronous motor, and provides a voltage feedforward control method and a voltage feedforward control device based on a permanent magnet synchronous motor model.

Background

In order to ensure the smooth and stable input of the current feedforward instruction, the traditional current feedforward instruction system carries out low-pass filtering calculation on the current feedforward instruction, and an upper computer inputs a current instruction i_refObtaining a current loop acceleration command a through calculation processing_refIs subjected to low pass filteringWave link to obtain acceleration feedforward command a_fAnd then according to the rotational inertia J of the permanent magnet synchronous motor_mAnd motor torque coefficient K_ATObtaining a feed-forward current value i_fFinally, the feed-forward voltage value U is obtained through calculation_fThe conventional feed forward structure diagram is shown in fig. 1 below.

From fig. 1 we can see the conventional feedforward calculation process, in which the low-pass filter coefficient K of the low-pass filter module is shown as equation (1):

in the formula: τ is the low pass filtering time.

Thereby obtaining an acceleration feedforward command a_fAs shown in formula (2):

a_f＝Ka_ref。 (2)

discretizing the formula (2) to obtain a formula (3):

in the formula: τ is a filter time constant; t is_sControlling a cycle time constant for the control system; and K is a low-pass filter coefficient.

The discretized acceleration feedforward command is obtained as shown in equation (4):

let k be the current control period, k-1 be the last control period, and the discretized acceleration feedforward instruction a in the current control period can be obtained from the formula (4)_f(k)As shown in formula (5):

further calculating to obtain a low-pass filtering feedforward current i_f(k)As shown in formula (6):

further, the low-pass filtering voltage feedforward U is obtained_f(k)As shown in formula (7):

U_f(k)＝(i_f(k)-i_f(k-1))L (7)

the traditional low-pass filtering voltage feedforward instruction U is obtained by the method_f(k)The low-pass filtering time coefficient τ often needs engineering experience to determine a value, and the low-pass filtering may cause amplitude distortion of the signal command, as shown in fig. 2, both amplitude and phase of the feedforward signal processed by the low-pass filtering signal are deviated.

Disclosure of Invention

Aiming at the problems, the invention provides a voltage feedforward control method and a voltage feedforward control device based on a permanent magnet synchronous motor model, aiming at improving the precision of a feedforward instruction and improving the current loop response capability of a control system.

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

(1) establishing a mathematical model of the permanent magnet synchronous motor to obtain a d-q voltage instruction output equation;

(2) carrying out space vector coordinate transformation on three-phase feedback current of the permanent magnet synchronous motor to obtain d-q axis feedback current;

(3) establishing a current loop feedback control loop;

(4) constructing a current loop feedforward control structure according to a mathematical model of the permanent magnet synchronous motor;

(5) injecting the output voltage feedforward instruction into a current loop feedback control loop to complete current loop closed-loop calculation;

(6) performing space vector coordinate transformation on the d-q axis command voltage to obtain a three-phase voltage command output value of the permanent magnet synchronous motor;

(7) and inputting the three-phase voltage command into a power amplification and modulation unit, and outputting a three-phase pulse width modulation wave with the amplitude value of the bus voltage by the power amplification and modulation unit to drive the permanent magnet synchronous motor unit to rotate.

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

the mathematical model of the permanent magnet synchronous motor is shown as formula (1):

in the formula: u shape_d、U_qFor d-axis and q-axis stator voltage commands L_d、L_qEquivalent inductances of a d axis and a q axis; r_sIs a stator resistor; omega_eIs the electrical angular velocity;is a rotor flux linkage; i.e. i_d、i_qThe currents are fed back for the d-axis and q-axis stators.

The motor torque model is shown as formula (2):

in the formula: t is_eIs an electromagnetic torque; p is the number of pole pairs of the motor.

The mechanical equation of motion is shown in equation (3):

in the formula: t is₁Is the load torque; omega_mIs the mechanical angular velocity; f is the motor friction factor; j is the moment of inertia of the motor.

In order to realize the maximum torque control, a d-axis current instruction i is given_dWhen the motor torque output equation is 0, the motor torque output equation is expressed by equation (4):

preferably, the step (2) is realized by the following method:

three-phase current is collected from three phases of the permanent magnet synchronous motor to obtain three-phase feedback phase current i_u、i_v、i_wThrough the space vectorThe standard change is used for obtaining d-q axis feedback current i_d、i_qAs shown in formula (5):

preferably, the step (3) is realized by the following method:

discretizing the mathematical model of the permanent magnet synchronous motor according to the mathematical model of the permanent magnet synchronous motor in the step (1), adopting a PI (proportional integral) controller to realize the calculation of a d-q axis voltage command, wherein k represents the current calculation period, k-1 represents the last calculation period, and according to the current calculation period, obtaining a current command value i_dref、i_qrefAnd the actual d-q axis current feedback value i_d、i_qObtaining a current feedback deviation i_{d_err}、i_{q_err}As shown in formula (6):

current feedback error i according to current calculation period_{d_err(k)}、i_{q_err(k)}And an integral coefficient K_iFor current error integral value i_{d_org(k)}、i_{q_org(k)}Solving is carried out as shown in equation (7):

current error integral value i obtained according to current calculation period_{d_org(k)}、i_{q_org(k)}Feedback current i_d(k)、i_q(k)And a proportionality coefficient K_vSolving the d-q axis control voltage command is shown in the formula (8):

wherein Rs is the equivalent resistance of the permanent magnet synchronous motor L_d、L_qIs the d-q axis equivalent inductance value, omega, of the permanent magnet synchronous motor_eIs the electric angle rotating speed value of the permanent magnet synchronous motor,is the equivalent flux linkage coefficient of the permanent magnet synchronous motor.

Preferably, the step (4) is realized by the following method:

adopting a PI controller to realize the calculation of a d-q axis feedforward voltage instruction, wherein k represents the current calculation period, k-1 represents the last calculation period, and taking a q axis current feedforward instruction as an example, according to the current calculation period current instruction value i_qrefQ-axis current feedback value i of current loop feedforward structure_FFFBObtaining a feedforward current feedback deviation i_{qff_err}As shown in formula (9):

i_{qff_err(k)}＝i_qref(k)-i_FFFB(k)(9)

current feedback error i according to current calculation period_{qff_err(k)}And current feedforward integral coefficient K_CiFFFor feedforward current error integral value i_{qff_org(k)}Solving is carried out as shown in equation (10):

i_{qff_org(k)}＝i_{qff_org(k-1)}+i_{qff_err(k)}*K_CiFF(10)

feedforward current error integral value i obtained according to current calculation period_{qff_org(k)}Feedback current i of feedforward closed loop_FFFB(k)And feedforward proportionality coefficient K_CvFFFeedforward control voltage U to q axis_qff(k)Solving is carried out as shown in equation (11):

U_qff(k)＝(i_{qff_org(k)}-i_FFFB(k))K_CvFFL_FF-R_FFi_FFFB(k)(11)

in the formula: r_FFL, a feedforward structural equivalent resistance of a permanent magnet synchronous motor_FFThe equivalent inductance value is fed forward for the permanent magnet synchronous motor.

For the feedforward output voltage value U of the q axis_qff(k)Limiting the amplitude value to make it not exceed the bus voltage V_dcTo obtain a final feedforward voltage command U_qffout(k)As shown in equation (12):

integrating the feedforward voltage command is shown in equation (13):

obtaining the feedback current i of the feedforward current loop through the process_FFFBThereby achieving closed loop control of the feed forward current loop.

Preferably, the step (5) is realized by the following method:

feed-forward voltage instruction U in closed loop of q-axis feed-forward current_qffoutIntroducing a current loop feedback loop, wherein the current loop q-axis voltage instruction U subjected to voltage feedforward injection_qoutAs shown in equation (14):

U_qout＝U_qffout+U_q(14)

the d-axis voltage command U can be obtained by the same method_dout；

Preferably, the step (6) is realized by the following method:

d-q axis feedback current i obtained in the step (2)_d、i_qThe d-q axis voltage command U obtained in the step (5) is substituted into a discretized d-q axis voltage control equation_dout、U_qoutSpace vector coordinate transformation is carried out to obtain three-phase voltage command U_u、U_v、U_wAs shown in equation (15):

preferably, the step (7) is realized by the following method:

the three-phase voltage instruction U obtained in the step (6) is processed_u,v,wAnd outputting the three-phase pulse width modulation waveform to a power modulation unit for power amplification, and outputting the three-phase pulse width modulation waveform subjected to power amplification to drive the motor to rotate.

Preferably, the device of the voltage feedforward control method based on the permanent magnet synchronous motor model comprises:

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;

an encoder unit for measuring the current position of the rotor angle of the PMSM unit and outputting the mechanical rotor angle theta of the PMSM unit_m；

An electrical angle conversion unit for converting the mechanical rotation angle theta obtained by the encoder unit_mConversion into electrical angle theta for space vector coordinate transformation calculation of permanent magnet synchronous motor_e；

A current sensor unit 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_wThe subsequent calculation processing is convenient;

a three-phase current space vector conversion unit for converting the current digital signal i obtained by the A/D conversion unit_u、i_v、i_wAnd an electrical angle theta obtained by the electrical angle conversion unit_eThree-phase current space vector coordinate change is carried out to obtain d-q axis feedback currents id and i_q；

A speed calculation unit for calculating the feedback speed omega of the rotor of the PMSM unit_mAnd feeding back the speed omega of the rotor_mConversion to electrical angle omega_e；

A current instruction unit for receiving a current instruction value i sent by the upper computer_dref、i_qref；

A voltage feedforward calculation unit for calculating a feedforward voltage command U of the control system_qffout、U_dffout；

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_qA feedforward voltage command U obtained by the voltage feedforward calculation unit_qff、U_dffAnd d-q axis voltage command U_d、U_qCombining to obtain a final d-q axis voltage command U_qout、U_doutFurther, according to U_qout、U_doutSpace vector coordinate transformation is carried out to obtain a three-phase voltage output instruction U_u、U_v、U_w；

A power modulation unit for outputting three-phase voltage output signal U_u,v,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 voltage feedforward control method based on the permanent magnet synchronous motor model can effectively improve the response characteristic of a current loop of a control system;

(2) the current feedforward control structure established according to the permanent magnet synchronous motor model can output an accurate voltage feedforward instruction, and the feedforward instruction deviation caused by the traditional low-pass filtering feedforward method is solved;

(3) the feedforward instruction calculation provided by the invention is obtained by calculation in an independent feedforward closed-loop system, is not influenced by a feedback link and external disturbance, and improves the robustness and disturbance resistance of a control system.

Drawings

FIG. 1 is a current low pass filter feed forward schematic;

FIG. 2 is a waveform diagram of low pass filtered signal processing;

FIG. 3 is a schematic structural diagram of a voltage feedforward control method based on a permanent magnet synchronous motor model;

FIG. 4 is a feed forward block diagram of a current loop;

FIG. 5 is a block diagram of a current loop solver control;

FIG. 6 is a block diagram of a feed forward voltage injection current feedback closed loop control;

FIG. 7 is a graph comparing current tracking effects of conventional low pass filtered feedforward with the feedforward method of the present invention;

Detailed Description

Hereinafter, embodiments of the present invention are described in detail with reference to the accompanying drawings.

As shown in fig. 3, a schematic structural diagram of a voltage feedforward control method based on a permanent magnet synchronous motor model includes:

the permanent magnet synchronous motor unit 1 is characterized in that a three-phase stator coil of the permanent magnet synchronous motor unit 1 receives a pulse width modulation waveform output by the power modulation unit 10 and drives a rotor to rotate;

an encoder unit 2 for measuring the current position of the rotor angle of the permanent magnet synchronous motor unit 1 and outputting the mechanical rotor angle theta of the permanent magnet synchronous motor unit_m；

An electrical angle conversion unit 3 for converting the mechanical rotation angle theta obtained by the encoder unit 2_mConversion into electrical angle theta for space vector coordinate transformation calculation of permanent magnet synchronous motor_eAs shown in formula (1):

θ_e＝θ_m*P (1)

in the formula: p is the number of pole pairs of the rotor of the permanent magnet synchronous motor;

an analog-to-digital conversion unit 4 for converting the analog signal output by the current sensor unit 8 into digital signals iu, i_v、i_wThe subsequent calculation processing is convenient;

a three-phase current space vector conversion unit 5 for converting the current digital signal i obtained by the A/D conversion unit 4_u、i_v、i_wAnd the electrical angle theta obtained by the electrical angle conversion unit 3_eThe space vector coordinate change of the three-phase current is carried out to obtain the feedback current i of the d-q axis_d、i_qAs shown in formula (2):

a speed calculation unit 6 for calculating a rotor feedback speed ω of the PMSM unit 1_mAnd feeding back the speed omega of the rotor_mConversion to electrical angle omega_eAs shown in formula (3):

ω_e＝ω_m*P (3)

a voltage feedforward calculation unit 7 for calculating a feedforward voltage command U of the control system_qffout、U_dffoutWherein, the structure diagram of the current loop feedforward is shown in fig. 4, and the specific implementation process is as follows:

and (3) calculating a d-q axis feedforward voltage command by adopting a PI controller, wherein k represents the current calculation period, and k-1 represents the last calculation period. Taking the q-axis current feedforward instruction as an example, the current instruction value i is calculated according to the current period_qrefQ-axis current feedback value i of current loop feedforward structure_FFFBObtaining a feedforward current feedback deviation i_{qff_err}As shown in formula (4):

i_{qff_err(k)}＝i_qref(k)-i_FFFB(k)(4)

current feedback error i according to current calculation period_{qff_err(k)}And current feedforward integral coefficient K_CiFFFor feedforward current error integral value i_{qff_org(k)}Solving is carried out as shown in formula (5):

i_{qff_org(k)}＝i_{qff_org(k-1)}+i_{qff_err(k)}K_CiFF(5)

feedforward current error integral value i obtained according to current calculation period_{qff_org(k)}Feedback current i of feedforward closed loop_FFFB(k)And feedforward proportionality coefficient K_CvFFFeedforward control voltage U to q axis_qff(k)Solving is carried out as shown in equation (6):

U_qff(k)＝(i_{qff_org(k)}-i_FFFB(k))K_CvFFL_FF-R_FFi_FFFB(k)(6)

in the formula: r_FFL, a feedforward structural equivalent resistance of a permanent magnet synchronous motor_FFFeeding forward an equivalent inductance value for the permanent magnet synchronous motor;

for the feedforward output voltage value U of the q axis_qff(k)Limiting the amplitude value to make it not exceed the bus voltage V_dcTo obtain a final feedforward voltage command U_qffout(k)As shown in formula (7):

integrating the feedforward voltage command is shown in equation (8):

obtaining the feedback current i of the feedforward current loop through the process_FFFBThereby achieving closed loop control of the feed forward current loop.

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

a current loop resolving unit 9 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_qAccording to the mathematical model of the permanent magnet synchronous motor, discretizing the mathematical model of the permanent magnet synchronous motor, and realizing the calculation of a d-q axis voltage command by adopting a PI controller, wherein k represents the current calculation period, k-1 represents the last calculation period, a control block diagram of a current loop resolving unit is shown in FIG. 5, and the specific implementation process is as follows:

according to the current calculation period current instruction value i_dref、i_qrefAnd the actual d-q axis current feedback value i_d、i_qObtaining a current feedback deviation i_{d_err}、i_{q_err}As shown in formula (9):

current feedback error i according to current calculation period_{d_err(k)}、i_{q_err(k)}And an integral coefficient K_iFor current error integral value i_{d_org(k)}、i_{q_org(k)}Solving is carried out as shown in equation (10):

current error integral value i obtained according to current calculation period_{d_org(k)}、i_{q_org(k)}Feedback current i_d(k)、i_q(k)And a proportionality coefficient K_vSolving the d-q axis control voltage command is shown in the formula (11):

wherein Rs is the equivalent resistance of the permanent magnet synchronous motor L_d、L_qIs the d-q axis equivalent inductance value, omega, of the permanent magnet synchronous motor_eIs the electric angle rotating speed value of the permanent magnet synchronous motor,is the equivalent flux linkage coefficient of the permanent magnet synchronous motor.

Feedforward voltage command U obtained by voltage feedforward calculation unit 7_qffout、U_dffoutAnd d-q axis voltage command U_d、U_qCombining to obtain a final d-q axis voltage command U_dout,U_qoutA feedforward voltage command U in a closed loop of a feedforward current_{dffout-qffout}The current loop feedback loop is introduced, for example, q-axis control voltage calculation, the feedforward voltage injection current feedback closed loop control block diagram is shown in fig. 6, and at this time, the current loop feedback circuit q-axis voltage instruction U after voltage feedforward injection_qoutAs shown in equation (12):

U_qout＝U_qffout+U_q(12)

the d-axis voltage command U can be obtained by the same method_dout。

According to U_qout、U_doutSpace vector coordinate transformation is carried out to obtain a three-phase voltage output instruction U_u、U_v、U_wAs shown in formula (13):

a power modulation unit 10 for outputting a three-phase voltage output signal U_u,v,wAmplifying power, and outputting bus voltage V as amplitude_dcThe pulse width modulation waveform of the permanent magnet synchronous motor drives the permanent magnet synchronous motor unit to rotate;

a current instruction unit 11 for receiving a current instruction value i sent by the upper computer_dref、i_qref。

FIG. 7 shows the feed forward voltage command applied to the current loop K according to the present invention_CvFF＝1400，K_CiFF1000, in this case, the waveform is compared with the waveform of the conventional low-pass filter feedforward command current loop τ of 0.0002 s. As can be seen from the figure, the actual tracking feedback value of the current of the low-pass filtering feedforward method does not reach the maximum value of the instruction, and the tracking is unstable. However, the voltage feedforward method based on the permanent magnet synchronous motor model provided by the invention has high current response speed and stable instruction tracking in the whole process.

The feasibility and prospect of popularization and application of the invention are predicted:

the current loop control is the most core part of the servo control system, and the response performance of the current loop determines the response capability of the servo control system.

It should be noted that the above-mentioned embodiments described with reference to the drawings are only intended to illustrate the present invention and not to limit the scope of the present invention, and it should be understood by those skilled in the art that modifications and equivalent substitutions can be made without departing from the spirit and scope of the present invention. Furthermore, unless the context indicates otherwise, words that appear in the singular include the plural and vice versa. Additionally, all or a portion of any embodiment may be utilized with all or a portion of any other embodiment, unless stated otherwise.