阅读说明：本技术 一种用于永磁同步电机电流环预测的控制方法及系统 (Control method and system for prediction of current loop of permanent magnet synchronous motor ) 是由 王浩宇 张雪玲 孟祥适 于 2020-05-21 设计创作，主要内容包括：本发明涉及一种用于永磁同步电机电流环预测的控制方法及系统,属于自动控制技术领域,解决了传统的控制器存在的控制成本高且鲁棒性较差等问题。采集永磁同步电机d、q轴的电流值与电压值；获得永磁同步电机q轴电流的参考值；建立电流无差拍控制模型；将永磁同步电机d、q轴的电流值与电压值和永磁同步电机q轴电流的参考值输入电流无差拍控制模型,得到下一时刻q轴的预测电压；以及,得到下一时刻d轴的预测电压；基于下一时刻q轴的预测电压和d轴的预测电压得到PWM控制信号并输入至与永磁同步电机相连接的逆变器,以实现对永磁同步电机的驱动控制。节省了控制成本,提高了控制器的鲁棒性。(The invention relates to a control method and a control system for prediction of a current loop of a permanent magnet synchronous motor, belongs to the technical field of automatic control, and solves the problems of high control cost, poor robustness and the like of a traditional controller. Collecting current values and voltage values of d and q axes of the permanent magnet synchronous motor; obtaining a reference value of a q-axis current of the permanent magnet synchronous motor; establishing a current dead-beat control model; inputting current values and voltage values of d and q axes of the permanent magnet synchronous motor and a reference value of q axis current of the permanent magnet synchronous motor into a current dead-beat control model to obtain predicted voltage of the q axis at the next moment; and obtaining the predicted voltage of the d axis at the next moment; and obtaining a PWM control signal based on the predicted voltage of the q axis and the predicted voltage of the d axis at the next moment, and inputting the PWM control signal to an inverter connected with the permanent magnet synchronous motor so as to realize the drive control of the permanent magnet synchronous motor. The control cost is saved, and the robustness of the controller is improved.)

1. A control method for predicting a current loop of a permanent magnet synchronous motor is characterized by comprising the following steps:

collecting current values and voltage values of d and q axes of the permanent magnet synchronous motor;

obtaining a reference value i of a q-axis current of the permanent magnet synchronous motor_qref；

The current values and the voltage values of d and q axes of the permanent magnet synchronous motor and the reference value i of q axis current of the permanent magnet synchronous motor are compared_qrefInputting the current dead-beat control model to obtain the predicted voltage of the q axis at the next moment; and collecting the current value of the d axis of the permanent magnet synchronous motor and the reference value i of the d axis current_drefInputting the obtained difference result into a PI controller to obtain the predicted voltage of the d axis at the next moment;

and obtaining a PWM control signal based on the predicted voltage of the q axis and the predicted voltage of the d axis at the next moment, and inputting the PWM control signal to an inverter connected with the permanent magnet synchronous motor so as to realize the drive control of the permanent magnet synchronous motor.

2. The control method according to claim 1, characterized in that the formula of the established current deadbeat control model is as follows:

in the formula, L_SIs equivalent inductance of the permanent magnet synchronous motor, R is stator resistance of the permanent magnet synchronous motor, omega_rIs the mechanical speed of the motor,. psi_fIs the rotor flux linkage of a permanent magnet synchronous machine i_q(k)Q-axis current i at time k of permanent magnet synchronous motor_d(k)D-axis current, u, at time k of the PMSM_q(k)Q-axis voltage, u, at time k of the PMSM_d(k)D-axis voltage u at time k of the PMSM_q(k+1)Q-axis current, u, at time k +1 of the PMSM_d(k+1)D-axis current i at the moment k +1 of the permanent magnet synchronous motor_qrefIs a reference value, i, of the q-axis current of the permanent magnet synchronous motor_drefIs a reference value, T, of d-axis current of the permanent magnet synchronous motor_SIs the sampling period of the current loop.

3. Control method according to claim 1 or 2, characterized in that a reference value i of the permanent magnet synchronous motor q-axis current is obtained_qrefThe method comprises the following steps:

acquiring a position digital signal and a position given signal of the current position of the permanent magnet synchronous motor, and converting the position given signal into a position given digital signal;

determining an initial value of a position ring proportion coefficient, obtaining the proportion coefficient of the position ring, and carrying out proportion operation on the basis of the proportion coefficient of the position ring, a position digital signal and a position given digital signal to obtain an initial speed given signal;

performing feedforward compensation on the position loop to obtain a feedforward compensation quantity of a speed given signal;

superposing and summing the feedforward compensation quantities of the initial speed given signal and the speed given signal to obtain a speed given signal omega_r ^*；

Differentiating the position digital signal to obtain a speed feedback signal;

based on the speed given signal ω_r ^*And a speed feedback signal is obtained, and a reference value i of the q-axis current of the permanent magnet synchronous motor is obtained by utilizing a PI (proportional integral) controller_qref。

4. A control system for predicting a current loop of a permanent magnet synchronous motor is characterized by comprising a controller, an inverter, a position sensor, a current and voltage acquisition circuit and an upper computer;

the position sensor is used for acquiring a position analog signal of the current position of the permanent magnet synchronous motor; the current and voltage acquisition circuit is used for acquiring current values and voltage values of d and q axes of the permanent magnet synchronous motor; the inverter is connected with the permanent magnet synchronous motor and used for receiving the PWM control signal output by the controller so as to realize the drive control of the permanent magnet synchronous motor; the upper computer is used for outputting a position given signal to the controller;

the controller comprises an FPGA control module and a DSP control module which are connected through a bus interface, wherein the FPGA control module is used for converting d-axis and q-axis analog current signals and analog voltage signals output by a current and voltage acquisition circuit into digital current signals and digital voltage signals, converting position analog signals output by a position sensor and position given signals output by an upper computer into position digital signals and position given digital signals, and outputting the digital current signals, the digital voltage signals, the position given digital signals and the position digital signals to the DSP control module;

the DSP control module is used for obtaining a reference value i of the q-axis current of the permanent magnet synchronous motor according to the position digital signal and the position given digital signal output by the FPGA control module_qrefThe reference value i of the q-axis current of the permanent magnet synchronous motor is calculated_qrefInputting the digital current signal and the digital voltage signal into a built current dead-beat control model to obtain a predicted voltage of a q axis at the next moment; and comparing the d-axis current value of the permanent magnet synchronous motor with a reference value i of the d-axis current_drefInputting the obtained result after difference into a PI controller to obtain the predicted voltage of the d axis at the next moment; and inputting a PWM control signal obtained based on the predicted voltage of the q axis and the predicted voltage of the d axis at the next moment to the inverter.

5. The control system according to claim 4, wherein the current deadbeat control model built by the DSP control module is expressed as:

in the formula, L_SIs equivalent inductance of the permanent magnet synchronous motor, R is stator resistance of the permanent magnet synchronous motor, omega_rIs the mechanical speed of the motor,. psi_fIs the rotor flux linkage of a permanent magnet synchronous machine i_q(k)Q-axis current i at time k of permanent magnet synchronous motor_d(k)D-axis current, u, at time k of the PMSM_q(k)Q-axis voltage, u, at time k of the PMSM_d(k)D-axis voltage u at time k of the PMSM_q(k+1)Q-axis current, u, at time k +1 of the PMSM_d(k+1)D-axis current i at the moment k +1 of the permanent magnet synchronous motor_qrefIs a reference value, i, of the q-axis current of the permanent magnet synchronous motor_drefReference value, T, for d-axis current of the motor_SIs the sampling period of the current loop.

6. Control system according to claim 5, characterized in that the reference value i of the permanent magnet synchronous motor q-axis current is obtained_qrefThe method comprises the following steps:

the FPGA control module receives a position analog signal output by the position sensor and a position given signal output by the upper computer at the same time, converts the position analog signal and the position given signal into a position digital signal and a position given digital signal and outputs the position digital signal and the position given digital signal to the DSP control module;

the DSP control module determines an initial value of a position ring proportion coefficient, obtains the proportion coefficient of the position ring, and performs proportion operation based on the proportion coefficient of the position ring, a position digital signal and a position given digital signal to obtain an initial speed given signal;

performing feedforward compensation on the position loop to obtain a feedforward compensation quantity of a speed given signal;

superposing and summing the feedforward compensation quantities of the initial speed given signal and the speed given signal to obtain a speed given signal omega_r ^*；

Differentiating the position digital signal to obtain a speed feedback signal;

based on the speed given signal ω_r ^*And a speed feedback signal is obtained, and a reference value i of the q-axis current of the permanent magnet synchronous motor is obtained by utilizing a PI (proportional integral) controller_qref。

7. The control system of claim 4, wherein the position sensor comprises a rotary transformer and an excitation signal unwinding circuit, wherein the rotary transformer is coaxially mounted with the permanent magnet synchronous motor, and the excitation signal unwinding circuit is connected with the FPGA control module;

the rotary transformer is used for measuring a position analog signal of the permanent magnet synchronous motor;

and the excitation signal derotation circuit is used for receiving and derotating the position analog signal output by the derotation transformer to obtain a position digital signal and outputting the position digital signal to the FPGA control module.

8. The control system of claim 7, wherein the excitation signal derotation circuit comprises a filter phase shift circuit and a derotation chip;

the filtering phase shift circuit is used for correcting the phase and amplitude of the position analog signal output by the rotary transformer to obtain a corrected position analog signal;

and the derotation chip is used for converting the corrected position analog signal output by the filtering phase shift circuit into a position digital signal and outputting the position digital signal to the FPGA control module.

9. The control system of claim 4, further comprising a power strip module for powering the controller and the current and voltage acquisition circuit.

10. The control system of claim 9, wherein the power strip module includes a DC/DC conversion unit and a protection unit;

the DC/DC conversion unit is used for converting the 28V direct current into 5V and 12V and respectively supplying power to the controller and the current and voltage acquisition circuit;

and the protection unit is used for detecting the current of the power panel module and realizing overcurrent protection and relay protection functions.

Technical Field

The invention relates to the technical field of automatic control, in particular to a control method and a control system for prediction of a current loop of a permanent magnet synchronous motor.

Background

A Permanent Magnet Synchronous Motor (PMSM) has the characteristics of simple structure, high reliability, large power factor, high energy utilization rate, hard mechanical property, wide speed regulation range and the like, so that the PMSM is widely applied to the fields of aerospace, automobiles, numerical control machines, robots and the like.

When the traditional PID controller is used for controlling the permanent magnet synchronous motor, due to the nonlinear and variable coupling characteristics of the motor, the traditional controller needs to debug parameters under different use working conditions of the motor, time and resources are wasted, and the traditional controller is high in control cost and poor in robustness.

In order to solve the problems of high control cost and poor robustness of a traditional controller, the application provides a control method and a control system for predicting a current loop of a permanent magnet synchronous motor.

Disclosure of Invention

In view of the foregoing analysis, embodiments of the present invention provide a control method and system for current loop prediction of a permanent magnet synchronous motor, so as to solve the problems of high control cost and poor robustness of the conventional controller.

In one aspect, an embodiment of the present invention provides a control method for prediction of a current loop of a permanent magnet synchronous motor, including the following steps:

collecting current values and voltage values of d and q axes of the permanent magnet synchronous motor;

obtaining a reference value i of a q-axis current of the permanent magnet synchronous motor_qref；

Establishing a current dead-beat control model, wherein the current dead-beat control model obtains the predicted voltage of the q axis of the permanent magnet synchronous motor at the next moment based on the current values and the voltage values of the d axis and the q axis of the permanent magnet synchronous motor at the current moment;

the current values and the voltage values of d and q axes of the permanent magnet synchronous motor and the reference value i of q axis current of the permanent magnet synchronous motor are compared_qrefSimultaneously inputting the current dead-beat control model to obtain the predicted voltage of the q axis at the next moment; and the collected d-axis of the permanent magnet synchronous motorReference value i of current value and d-axis current_drefInputting the obtained difference result into a PI controller to obtain the predicted voltage of the d axis at the next moment;

and obtaining a PWM control signal based on the predicted voltage of the q axis and the predicted voltage of the d axis at the next moment, and inputting the PWM control signal to an inverter connected with the permanent magnet synchronous motor so as to realize the drive control of the permanent magnet synchronous motor.

Further, the formula of the current deadbeat control model is as follows:

in the formula, L_SIs equivalent inductance of the permanent magnet synchronous motor, R is stator resistance of the permanent magnet synchronous motor, omega_rIs the mechanical speed of the motor,. psi_fIs the rotor flux linkage of a permanent magnet synchronous machine i_q(k)Q-axis current i at time k of permanent magnet synchronous motor_d(k)D-axis current, u, at time k of the PMSM_q(k)Q-axis voltage, u, at time k of the PMSM_d(k)D-axis voltage u at time k of the PMSM_q(k+1)Q-axis current, u, at time k +1 of the PMSM_d(k+1)D-axis current i at the moment k +1 of the permanent magnet synchronous motor_qrefIs a reference value, i, of the q-axis current of the permanent magnet synchronous motor_drefIs a reference value, T, of d-axis current of the permanent magnet synchronous motor_SIs the sampling period of the current loop.

Further, a reference value i of the q-axis current of the permanent magnet synchronous motor is obtained_qrefThe method comprises the following steps:

acquiring a position digital signal and a position given signal of the current position of the permanent magnet synchronous motor, and converting the position given signal into a position given digital signal;

determining an initial value of a position ring proportion coefficient, obtaining the proportion coefficient of the position ring, and carrying out proportion operation based on the proportion coefficient of the position ring, a position digital signal and a position given signal to obtain an initial speed given signal;

performing feedforward compensation on the position loop to obtain a feedforward compensation quantity of a speed given signal;

superposing and summing the feedforward compensation quantities of the initial speed given signal and the speed given signal to obtain a speed given signal omega_r ^*；

Differentiating the position digital signal to obtain a speed feedback signal;

based on the speed given signal ω_r ^*And a speed feedback signal is obtained, and a reference value i of the q-axis current of the permanent magnet synchronous motor is obtained by utilizing a PI (proportional integral) controller_qref。

On the other hand, the embodiment of the invention provides a control system for predicting a current loop of a permanent magnet synchronous motor, which comprises a controller, an inverter, a position sensor and a current and voltage acquisition circuit, wherein the controller is connected with the inverter;

the position sensor is used for acquiring a position analog signal of the current position of the permanent magnet synchronous motor; the current and voltage acquisition circuit is used for acquiring current values and voltage values of d and q axes of the permanent magnet synchronous motor; the inverter is connected with the permanent magnet synchronous motor and used for receiving the PWM control signal output by the controller so as to realize the drive control of the permanent magnet synchronous motor; the upper computer is used for outputting a position given signal to the controller;

the controller comprises an FPGA control module and a DSP control module which are connected through a bus interface, wherein the FPGA control module is used for converting d-axis and q-axis analog current signals and analog voltage signals output by a current and voltage acquisition circuit into digital current signals and digital voltage signals, converting position analog signals output by a position sensor and position given signals output by an upper computer into position digital signals and position given digital signals, and outputting the digital current signals, the digital voltage signals, the position given digital signals and the position digital signals to the DSP control module;

the DSP control module is used for giving a number according to the position digital signal and the position output by the FPGA control moduleObtaining a reference value i of the q-axis current of the permanent magnet synchronous motor by the word signal_qrefThe reference value i of the q-axis current of the permanent magnet synchronous motor is calculated_qrefInputting the digital current signal and the digital voltage signal into a built current dead-beat control model to obtain a predicted voltage of a q axis at the next moment; and comparing the d-axis current value of the permanent magnet synchronous motor with a reference value i of the d-axis current_drefInputting the obtained result after difference into a PI controller to obtain the predicted voltage of the d axis at the next moment; and inputting a PWM control signal obtained based on the predicted voltage of the q axis and the predicted voltage of the d axis at the next moment to the inverter.

Further, the current dead-beat control model built by the DSP control module is expressed as follows:

in the formula, L_SIs equivalent inductance of the permanent magnet synchronous motor, R is stator resistance of the permanent magnet synchronous motor, omega_rIs the mechanical speed of the motor,. psi_fIs the rotor flux linkage of a permanent magnet synchronous machine i_q(k)Q-axis current i at time k of permanent magnet synchronous motor_d(k)D-axis current, u, at time k of the PMSM_q(k)Q-axis voltage, u, at time k of the PMSM_d(k)D-axis voltage u at time k of the PMSM_q(k+1)Q-axis current, u, at time k +1 of the PMSM_d(k+1)D-axis current i at the moment k +1 of the permanent magnet synchronous motor_qrefIs a reference value, i, of the q-axis current of the permanent magnet synchronous motor_drefReference value, T, for d-axis current of the motor_SIs the sampling period of the current loop.

Further, a reference value i of the q-axis current of the permanent magnet synchronous motor is obtained_qrefThe method comprises the following steps:

the FPGA control module receives a position digital signal output by a position sensor and a position given signal output by an upper computer at the same time, converts the position given signal into a position given digital signal, and outputs the position digital signal and the position given digital signal to the DSP control module;

the DSP control module determines an initial value of a position ring proportion coefficient, obtains the proportion coefficient of the position ring, and performs proportion operation based on the proportion coefficient of the position ring, a position digital signal and a position given digital signal to obtain an initial speed given signal;

performing feedforward compensation on the position loop to obtain a feedforward compensation quantity of a speed given signal;

superposing and summing the feedforward compensation quantities of the initial speed given signal and the speed given signal to obtain a speed given signal omega_r ^*；

Differentiating the position digital signal to obtain a speed feedback signal;

based on the speed given signal ω_r ^*And a speed feedback signal is obtained, and a reference value i of the q-axis current of the permanent magnet synchronous motor is obtained by utilizing a PI (proportional integral) controller_qref。

Further, the position sensor comprises a rotary transformer and an excitation signal unwinding circuit, wherein the rotary transformer and the permanent magnet synchronous motor are coaxially mounted, and the excitation signal unwinding circuit is connected with the FPGA control module;

the rotary transformer is used for measuring a position analog signal of the permanent magnet synchronous motor;

and the excitation signal derotation circuit is used for receiving and derotating the position analog signal output by the derotation transformer to obtain a position digital signal and outputting the position digital signal to the FPGA control module.

Furthermore, the excitation signal derotation circuit comprises a filtering phase shift circuit and a derotation chip;

the filtering phase shift circuit is used for correcting the phase and amplitude of the position analog signal output by the rotary transformer to obtain a corrected position analog signal;

and the derotation chip is used for converting the corrected position analog signal output by the filtering phase shift circuit into a position digital signal and outputting the position digital signal to the FPGA control module.

Furthermore, the control system also comprises a power panel module which is used for supplying power for the controller and the current and voltage acquisition circuit.

Further, the power panel module comprises a DC/DC conversion unit and a protection unit;

the DC/DC conversion unit is used for converting the 28V direct current into 5V and 12V and respectively supplying power to the controller and the current and voltage acquisition circuit;

and the protection unit is used for detecting the current of the power panel module and realizing overcurrent protection and relay protection.

Compared with the prior art, the invention can realize at least one of the following beneficial effects:

1. a control method for predicting a current loop of a permanent magnet synchronous motor is characterized in that a dead-beat current control model is built, a predicted voltage of a q axis at the next moment is obtained, and the drive control of the permanent magnet synchronous motor can be realized based on the obtained d and q axis predicted voltages as long as corresponding parameters and a sampling period of the permanent magnet synchronous motor are set in advance, so that the problems of high control cost and poor robustness of an existing controller are solved, the control cost is saved, and the robustness is improved.

2. A control system for predicting a current loop of a permanent magnet synchronous motor is characterized in that a dead-beat current control method is realized in a DSP control module of a controller, the DSP control module and an FPGA control module realize a communication function through a bus interface, and the DSP control module and the FPGA control module are definite in division of work and reasonable in task allocation and have high real-time performance.

3. Through the power panel module, the voltage required by operation is provided for the corresponding module in the control system, meanwhile, the overcurrent detection and relay protection functions of the circuit can be realized, and the reliability and stability of the control system are improved.

In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

FIG. 1 is a flow diagram of a control method for PMSM current loop prediction in one embodiment;

FIG. 2 is a diagram of an embodiment of a permanent magnet synchronous motor current prediction dual closed loop architecture;

FIG. 3 is a block diagram of a control system for PMSM current loop prediction in another embodiment;

FIG. 4 is a timing diagram of quadrature axis current control for a PMSM according to another embodiment;

FIG. 5 is a diagram of a controller software control architecture in another embodiment;

FIG. 6 is a schematic diagram showing a hardware configuration of a control system in another embodiment;

reference numerals:

the system comprises a 110-FPGA control module, a 120-DSP control module, a 200-inverter, a 300-permanent magnet synchronous motor, a 400-position sensor, a 500-current and voltage acquisition module and a 600-upper computer.

Detailed Description

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.

When the traditional PID controller is used for controlling the permanent magnet synchronous motor, parameters need to be debugged under different use working conditions of the motor due to the nonlinear and variable coupling characteristics of the motor, so that time and resources are wasted, and the robustness is poor. Aiming at the problems in the prior art, the application provides a control method and a control system for predicting a current loop of a permanent magnet synchronous motor. The control method is mainly used in a permanent magnet synchronous motor high-precision control system in the aerospace field, can improve the high precision and dynamic performance of the permanent magnet synchronous motor, has important significance on a satellite imaging technology and an earth observation system, can realize higher orbit scanning precision, can obtain clearer earth surface layer information by combining a satellite image processing technology, and plays an important role in social life and scientific research.

An embodiment of the present invention discloses a control method for prediction of a current loop of a permanent magnet synchronous motor, as shown in fig. 1. The method comprises the following steps:

step S1, collecting current values i of d and q axes of the permanent magnet synchronous motor at the current moment_d(k)、i_q(k)And a voltage value u_d(k)、u_q(k)。

Step S2, obtaining a reference value i of the q-axis current of the permanent magnet synchronous motor_qref. Specifically, a reference value i of q-axis current of the permanent magnet synchronous motor_qrefThe method is mainly obtained according to a position ring of the permanent magnet synchronous motor, and specifically comprises the following steps:

s201, acquiring a position digital signal and a position given signal of the current position of the permanent magnet synchronous motor, and converting the position given signal into the position given digital signal.

S202, determining an initial value of the position ring proportion coefficient, obtaining the proportion coefficient of the position ring, and carrying out proportion operation based on the proportion coefficient of the position ring, the position digital signal and the position given digital signal to obtain an initial speed given signal. Specifically, the position loop is controlled to be a first-order system, and the proportional coefficient of the position loop is initialized to a value K_PP0SelectingWherein K_PPIndicating the proportionality coefficient of the position loop, K_SRepresenting the velocity equivalent proportionality coefficient, T_sIs the velocity equivalent time constant. The scaling factor of the position ring can be obtained based on the initial value of the scaling factor of the position ring, wherein the calculation formula of the scaling factor of the position ringComprises the following steps: k_PP＝K_PP0+ΔK_PP|ω_rL, wherein K_PPIs a position loop scale factor, K_PP0Is an initial value of the position loop scale factor, Δ K_PPFeedback of velocity information adjustment factor, omega, for position loop_rThe mechanical rotation speed of the permanent magnet synchronous motor. And finally, carrying out proportional operation based on the proportional coefficient of the position ring, the position digital signal and the position given digital signal to obtain an initial speed given signal.

S203, performing feedforward compensation on the position loop to obtain a feedforward compensation quantity of the speed given signal. According to the calculation formula of feedforward compensationObtaining a feedforward compensation amount of the velocity given signal, wherein K_fIs a feed forward coefficient; t is_fThe time constant of the time delay of the feedforward link is half of the sampling period controlled by the position loop, and is generally 0.5 ms.

S204, superposing and summing the initial speed given signal and the feedforward compensation quantity of the speed given signal to obtain a speed given signal omega_r ^*The speed setting signal is an output signal of the position loop control and is also an input signal of the speed loop control.

And S205, differentiating the position digital signal to obtain a speed feedback signal. Giving speed to signal omega_r ^*And a speed feedback signal, the PI controller (speed loop) based on a speed given signal omega_r ^*And obtaining a reference value i of the q-axis current of the permanent magnet synchronous motor by the speed feedback signal_qref。

And step S3, establishing a current dead-beat control model, wherein the current dead-beat control model obtains the predicted voltage of the q axis of the permanent magnet synchronous motor at the next moment based on the current values and the voltage values of the d axis and the q axis of the permanent magnet synchronous motor at the current moment. Specifically, the current dead-beat control model is based on a bilinear transformation theory, a more accurate mathematical model is established, the influence of a rotor flux linkage permanent magnet vector on the stability of the model is eliminated in an incremental mode, the model is obtained through bilinear thought dispersion and is based on two-beat span, the precision is more accurate than that of a traditional discrete model, and the robustness of a controller is enhanced.

The specific calculation formula is as follows:

in the formula, L_SIs equivalent inductance of the permanent magnet synchronous motor, R is stator resistance of the permanent magnet synchronous motor, omega_rIs the mechanical speed of the motor,. psi_fIs the rotor flux linkage of a permanent magnet synchronous machine i_q(k)Q-axis current i at time k of permanent magnet synchronous motor_d(k)D-axis current, u, at time k of the PMSM_q(k)Q-axis voltage, u, at time k of the PMSM_d(k)D-axis voltage u at time k of the PMSM_q(k+1)Q-axis current, u, at time k +1 of the PMSM_d(k+1)D-axis current i at the moment k +1 of the permanent magnet synchronous motor_qrefIs a reference value, i, of the q-axis current of the permanent magnet synchronous motor_drefIs a reference value, T, of d-axis current of the permanent magnet synchronous motor_SIs the sampling period of the current loop.

Step S4, the current values and voltage values of the d and q axes of the permanent magnet synchronous motor and the reference value i of the q axis current of the permanent magnet synchronous motor_qrefSimultaneously, inputting a current dead-beat control model to obtain a predicted voltage of a q axis at the next moment; and collecting the current value of the d axis of the permanent magnet synchronous motor and the reference value i of the d axis current_drefAnd inputting the difference result into a PI controller to obtain the predicted voltage of the d axis at the next moment.

And step S5, obtaining a PWM control signal based on the predicted voltage of the q axis and the predicted voltage of the d axis at the next moment, and inputting the PWM control signal to an inverter connected with the permanent magnet synchronous motor to realize the drive control of the permanent magnet synchronous motor.

Specifically, a permanent magnet synchronous machine as shown in fig. 2The current prediction double-closed-loop structure diagram is characterized in that collected currents and voltages of d and q axes of the permanent magnet synchronous motor and reference values of q axis currents of the permanent magnet synchronous motor are input into a dead-beat current control model to obtain predicted voltages of the q axis at the next moment, and meanwhile, current values of the d axis of the permanent magnet synchronous motor and reference values i of the d axis currents are input into a dead-beat current control model_drefAnd inputting the obtained result after the difference is made into a PI controller to obtain the predicted voltage of the d axis at the next moment. Secondly, the obtained predicted voltage of the q axis and the predicted voltage of the d axis at the next moment are subjected to PARK conversion to obtain voltages u of alpha and beta axes_αAnd u_βThen u is added_αAnd u_βMeanwhile, the PWM control signal is input into the SVPWM module to obtain a PWM control signal, and the PWM control signal is input into an inverter connected with the permanent magnet synchronous motor so as to realize the drive control of the permanent magnet synchronous motor.

Compared with the prior art, the control method for predicting the current loop of the permanent magnet synchronous motor provided by the embodiment builds a discrete model of dead beat current control, obtains the predicted voltage of the q axis at the next moment, can realize the drive control of the permanent magnet synchronous motor based on the predicted voltages of the d axis and the q axis as long as the corresponding parameters and the sampling period of the permanent magnet synchronous motor are set in advance, solves the problems of high control cost and poor robustness of the existing controller, saves the control cost, and improves the robustness.

In another embodiment of the present invention, a control system for prediction of current loop of a permanent magnet synchronous motor is disclosed, as shown in fig. 3. The device comprises a controller, an inverter 200, a position sensor 400, a current and voltage acquisition circuit 500 and an upper computer 600; the position sensor 400 is used for acquiring a position analog signal of the current position of the permanent magnet synchronous motor 300; the current and voltage acquisition circuit 500 is used for acquiring d and q axis current values and voltage values of the permanent magnet synchronous motor 300; the inverter 200 is configured to receive a PWM control signal output by the controller, so as to implement driving control on the permanent magnet synchronous motor 300; and the upper computer 600 is used for outputting a position given signal to the FPGA control module. The controller comprises an FPGA control module 110 and a DSP control module 120 which are connected through a bus interface, wherein the FPGA control module 110 is used for simulating d and q axes output by the current and voltage acquisition circuitThe current signal and the analog voltage signal are converted into a digital current signal and a digital voltage signal, the position analog signal output by the position sensor and the position given signal output by the upper computer are converted into a position digital signal and a position given digital signal, and the digital current signal, the digital voltage signal, the position given digital signal and the position digital signal are output to the DSP control module. A DSP control module 120 for obtaining a reference value i of the q-axis current of the permanent magnet synchronous motor according to the position digital signal and the position given digital signal output by the FPGA control module_qrefAnd the reference value i of the q-axis current of the permanent magnet synchronous motor is compared_qrefInputting the digital current signal and the digital voltage signal into a built current dead-beat control model to obtain a predicted voltage of a q axis at the next moment; and comparing the d-axis current value of the permanent magnet synchronous motor with a reference value i of the d-axis current_drefInputting the obtained result after difference into a PI controller to obtain the predicted voltage of the d axis at the next moment; and a PWM control signal obtained based on the predicted voltage of the q-axis and the predicted voltage of the d-axis at the next time is input to the inverter.

When the system is implemented, the upper computer and the FPGA control module carry out serial port communication through R232. Meanwhile, the control system can also comprise an oscilloscope connected with the controller and used for displaying some important signals obtained by the controller in the operation process, such as current values and voltage values of d and q axes, and recording and analyzing the important signals.

Compared with the prior art, the control system for predicting the current loop of the permanent magnet synchronous motor, provided by the embodiment, builds a dead-beat current control model, obtains the predicted voltage of the q axis at the next moment, and can realize the drive control of the permanent magnet synchronous motor based on the predicted voltages of the d axis and the q axis as long as the corresponding parameters and the sampling period of the permanent magnet synchronous motor are set in advance, so that the problems of high control cost and poor robustness of the existing controller are solved, the control cost is saved, and the robustness is improved. Meanwhile, the dead-beat current control model is built for the current and the voltage of d and q axes based on collection, and compared with the performance that a traditional controller is sensitive to design parameters and weak in anti-interference capacity, the stability of the controller is better. Meanwhile, the deadbeat current control method is realized in a DSP control module of the controller, the DSP control module and an FPGA control module realize a communication function through a bus interface, and the DSP control module and the FPGA control module are clear in division of labor and reasonable in task allocation, so that the deadbeat current control method has high real-time performance.

Preferably, the current deadbeat control model built by the DSP control module is expressed as:

in the formula, L_SIs equivalent inductance of the permanent magnet synchronous motor, R is stator resistance of the permanent magnet synchronous motor, omega_rIs the mechanical speed of the motor,. psi_fIs the rotor flux linkage of a permanent magnet synchronous machine i_q(k)Q-axis current i at time k of permanent magnet synchronous motor_d(k)D-axis current, u, at time k of the PMSM_q(k)Q-axis voltage, u, at time k of the PMSM_d(k)D-axis voltage u at time k of the PMSM_q(k+1)Q-axis current, u, at time k +1 of the PMSM_d(k+1)D-axis current i at the moment k +1 of the permanent magnet synchronous motor_qrefIs a reference value, i, of the q-axis current of the permanent magnet synchronous motor_drefReference value, T, for d-axis current of the motor_SIs the sampling period of the current loop.

The current dead-beat control model built by the DSP control module obtains the predicted voltage of the q axis at the next moment, and the driving control of the permanent magnet synchronous motor can be realized based on the obtained predicted voltages of the d axis and the q axis as long as the corresponding parameters and the sampling period of the permanent magnet synchronous motor are set in advance, so that the problems of high control cost and poor robustness of the existing controller are solved, the control cost is saved, and the robustness is improved.

Specifically, a reference value i of a q-axis current of the permanent magnet synchronous motor is obtained_qrefThe method comprises the following steps: the FPGA control module simultaneously receives the bits output by the position sensorAnd the position given signal is converted into a position given digital signal, and the position digital signal and the position given digital signal are output to the DSP control module. The DSP control module determines an initial value of the position ring proportion coefficient, obtains the proportion coefficient of the position ring, and performs proportion operation based on the proportion coefficient of the position ring, the position digital signal and the position given signal to obtain an initial speed given signal. Specifically, the position loop is controlled to be a first-order system, and the proportional coefficient of the position loop is initialized to a value K_PP0SelectingWherein K_PPIndicating the proportionality coefficient of the position loop, K_SRepresenting the velocity equivalent proportionality coefficient, T_sIs the velocity equivalent time constant. The scaling factor of the position ring can be obtained based on the initial value of the scaling factor of the position ring, wherein the calculation formula of the scaling factor of the position ring is as follows: k_PP＝K_PP0+ΔK_PP|ω_rL, wherein K_PPIs a position loop scale factor, K_PP0Is an initial value of the position loop scale factor, Δ K_PPFeedback of velocity information adjustment factor, omega, for position loop_rThe mechanical rotation speed of the permanent magnet synchronous motor. And finally, carrying out proportional operation based on the proportional coefficient of the position ring, the position digital signal and the position given digital signal to obtain an initial speed given signal. Then, the position loop is subjected to feedforward compensation according to a calculation formula of the feedforward compensationObtaining a feedforward compensation amount of the velocity given signal, wherein K_fIs a feed forward coefficient; t is_fThe time constant of the time delay of the feedforward link is half of the sampling period controlled by the position loop, and is generally 0.5 ms. The feedforward compensation quantities of the initial speed given signal and the speed given signal are superposed and summed to obtain a speed given signal omega_r ^*The speed setting signal is an output signal of the position loop control and is also an input signal of the speed loop control. Finally, the position digital signal is differentiated to obtain a speed feedback signal, andspeed given signal omega_r ^*And a speed feedback signal, the PI controller (speed loop) based on a speed given signal omega_r ^*And obtaining a reference value i of the q-axis current of the permanent magnet synchronous motor by the speed feedback signal_qref。

By obtaining a reference value i of a q-axis current of the permanent magnet synchronous motor_qrefThe method provides basis and support for obtaining the predicted voltage value of the q axis at the next moment through the current dead-beat control model, and has important significance for realizing the driving of the permanent magnet synchronous motor.

Specifically, as shown in the quadrature axis current control timing diagram of the permanent magnet synchronous motor shown in fig. 4, at the time k, the DSP control module receives a set of current values acquired by the current and voltage acquisition module, and from the time k, the DSP control module performs calculation and processing of a control algorithm, and when the time k +1 times of interruption arrives, the DSP control module outputs a calculation result obtained by starting the calculation at the time k to the SVPMW module to generate a PWM control signal, and at the time k +2, the current value acquired by the current and voltage acquisition module is generated by calculating the current acquired at the time k through the DSP control module and applying the current to the inverter, so that the servo current closed-loop control has a delay of two control periods. Therefore, the current setting and feedback period of the permanent magnet synchronous motor is twice of the period of the controller, namely, the improved deadbeat control research on the quadrature axis current of the permanent magnet synchronous motor is developed based on two-beat time delay.

As shown in the controller software control architecture of fig. 5, the FPGA control module and the DSP control module in the controller can better cooperate with each other. The DSP control module enters a main cycle to wait for receiving an instruction of the host, the instruction is output to the DSP control module through a serial port by the host, the DSP control module enters a set operation mode after analyzing the instruction, the position and current signals of the permanent magnet synchronous motor obtained by the FPGA control module are read in the cycle, a control algorithm is executed, and a PWM signal is obtained and output to the inverter.

Preferably, the position sensor comprises a rotary transformer and an excitation signal unwinding circuit, wherein the rotary transformer and the permanent magnet synchronous motor are coaxially mounted, and the excitation signal unwinding circuit is connected with the FPGA control module; the rotary transformer is used for measuring a position analog signal of the permanent magnet synchronous motor; and the excitation signal unwinding circuit is used for receiving the position analog signal output by the unwinding transformer and unwinding the position analog signal to obtain a position digital signal and outputting the position digital signal to the FPGA control module. Specifically, the rotary transformer may be replaced with a photoelectric encoder for acquiring a position analog signal of the rotation of the motor shaft of the permanent magnet synchronous motor to the current position.

Preferably, the excitation signal derotation circuit comprises a filtering phase shift circuit and a derotation chip; the filtering phase-shifting circuit is used for correcting the phase and amplitude of the position analog signal output by the rotary transformer to obtain a corrected position analog signal; and the derotation chip is used for converting the corrected position analog signal output by the filtering phase shift circuit into a position digital signal and outputting the position digital signal to the FPGA control module.

Specifically, the filtering phase shift circuit can adjust the deviation of the phase and amplitude of the position analog signal output by the rotary transformer, and correct the error of the position analog signal caused by the process defect of the rotary transformer. Meanwhile, the AD2S80 series de-rotation chip is used for converting the corrected position analog signal output by the filtering phase-shifting circuit to obtain a position digital signal and outputting the position digital signal to the FPGA control module.

The output end of the permanent magnet synchronous motor is connected with a position sensor to form a position ring, and the position ring can collect a position analog signal of the motor shaft of the permanent magnet synchronous motor rotating to the current position and feed back the position analog signal to the controller. Meanwhile, a reference value i of q-axis current of the permanent magnet synchronous motor required by the dead beat current loop control model can be obtained through the position loop_qrefThe method provides basis and support for realizing the drive control of the permanent magnet synchronous motor, is simple and easy to implement and is easy to implement.

Preferably, as shown in fig. 4, the control system further includes a power panel module for supplying power to the controller and the current and voltage collecting circuit. Preferably, the power strip module includes a DC/DC conversion unit and a protection unit; the DC/DC conversion unit is used for converting the 28V direct current into 5V and 12V and respectively supplying power to the controller and the current and voltage acquisition circuit; and the protection unit is used for detecting the current of the power panel module and realizing overcurrent protection and relay protection.

Specifically, the power panel module is connected with a 28V direct current power supply, wherein a DC/DC conversion unit in the power panel module converts the 28V direct current into 5V and 12V direct current sources, the 5V direct current source is used for supplying power to an FPGA control module and a DSP module in the controller, and the 12V direct current source is used for supplying necessary voltage to a current and voltage acquisition circuit and a position sensor in the control system. The power panel module also comprises a protection unit, the protection unit can detect the current of the circuit and realize the overcurrent detection function, and meanwhile, when the circuit breaks down, the corresponding fault part can be cut off to realize the relay protection function.

Through the power panel module, the voltage required by operation is provided for the corresponding module in the control system, meanwhile, the overcurrent detection and relay protection functions of the circuit can be realized, and the reliability and stability of the control system are improved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.