阅读说明：本技术 一种内置式永磁同步电机控制方法 (Control method for built-in permanent magnet synchronous motor ) 是由 柴璐军 张瑞峰 杨高兴 贺志学 梁海刚 詹哲军 李岩 于 2019-10-29 设计创作，主要内容包括：本发明涉及永磁同步电机控制方法,具体为一种内置式永磁同步电机控制方法。解决现有永磁同步电机控制方法中没有实时而准确使用电机参数,因而电机输出的转矩精度和电机运行效率被影响的问题。本发明的控制方法同时在线考虑了温度变化和电机饱和效应对电机参数的影响,提高了电机在每个工作点参数的准确性；本发明在前馈通道上基于电机温度<I>t、</I>电流幅值<I>i</I><Sub><I>s</I></Sub><I>、</I>电流矢量角<I>β</I>在线实时查表和MTPA实时查表,反馈通道上使用磁链计算模型实时计算出磁链<Image he="24" wi="30" file="217388DEST_PATH_IMAGE002.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,省去了对转子温度的检测设备；且利用转矩闭环的输出结果重新分配了<I>d</I>轴电流<Image he="24" wi="14" file="462425DEST_PATH_IMAGE004.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>和<I>q</I>轴电流<Image he="27" wi="14" file="540365DEST_PATH_IMAGE006.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,维持永磁同步电机按照MTPA轨迹运行,降低了电机的发热和损耗。(The invention relates to a control method of a permanent magnet synchronous motor, in particular to a control method of a built-in permanent magnet synchronous motor. The method solves the problem that the motor parameters are not accurately used in real time in the existing permanent magnet synchronous motor control method, so that the torque precision output by the motor and the motor operation efficiency are influenced. The control method of the invention simultaneously considers the influence of temperature change and motor saturation effect on the motor parameters on line, and improves the accuracy of the motor parameters at each working point; the invention is based on motor temperature in the feed-forward path t、 Amplitude of current i s 、 Current vector angle β On-line real-time table look-up and MTPA real-time table look-up, and on feedback channel, using flux linkage calculation model to calculate flux linkage in real time Detection equipment for the temperature of the rotor is omitted; and redistribute output results using torque closed loop d Shaft current And q shaft current And the permanent magnet synchronous motor is maintained to run according to the MTPA track, so that the heating and the loss of the motor are reduced.)

1. A control method of a built-in permanent magnet synchronous motor is characterized by comprising the following control modules: the device comprises a temperature sensor module (1), a rotary transformer module (2), a Clark conversion module (3), a Park conversion module (4), a torque instruction processing module (5), an MTPA table look-up module (6), a stator inductance and resistance parameter table look-up module (7), a voltage calculation module, a flux linkage calculation module (9), a feedback torque calculation module (10), a current vector angle adjustment module (11) and a pulse modulation module (12);

1) temperature sensor module

The temperature sensor is buried in a permanent magnet synchronous motor stator, and the real-time stator temperature t of the motor is acquired by the temperature sensor;

2) rotary transformer module

The rotary transformer is arranged on the permanent magnet synchronous motor, the rotor position theta of the permanent magnet synchronous motor is acquired through the rotary transformer, and the rotating speed w of the permanent magnet synchronous motor can be obtained through differentiating the rotor position theta_e；

3) Clark conversion module

The current sensor collects two-phase current of the stator to obtain i_a、i_bThen obtaining stator current i through Clark conversion_α、i_β；

4) Park conversion module

Clark transformation module to obtain i_α、i_βObtaining the current i under a d-q rotating coordinate system through Park transformation_d、i_q；

5) Torque command processing module

The input of the torque command processing module is a target torque T_e(ii) a After amplitude limiting and torque slope processing, the output of the torque command processing module is given torque

6) MTPA table look-up module

The input in the MTPA look-up table module is

7) stator inductance and resistance parameter look-up table module

The input of the stator inductance and resistance parameter lookup module is a current amplitude value i_sCurrent vector angle β₁Stator temperature t, wherein current vector angle β₁Is obtained by correcting delta β output by the current vector angle adjusting module on the basis of β values obtained by the MTPA table look-up module;

the output of the stator inductance and resistance parameter lookup module is L_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t)、

Based on the temperature t and the current amplitude i of the stator of the motor_sCurrent vector angle β₁Looking up a table for an interpolation algorithm in real time to obtain a current-following amplitude i_sCurrent vector angle β₁Stator inductance L with variable stator temperature t_d(i_s、β₁、t)，L_q(i_s、β₁、t)；

Obtaining the stator resistance R changing along with the stator temperature through a real-time table look-up interpolation algorithm based on the motor temperature t_s(t)；

According to the current amplitude i_sCurrent vector angle β₁Obtaining a d-axis current set value according to the following formulaGiven value of q-axis current

Wherein L is determined_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t) the table is obtained using a parameter table provided by a motor designer, or by experiment;

8) voltage calculation module

The voltage calculation module consists of a front feed voltage module (8) and a current regulator module;

the input of the front feed voltage module is L_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t)、ψ_f(t₀)、Wherein the rotor flux linkage psi_f(t₀) Is at the nominal temperature; the output of the feed-forward voltage module is u_dfw、u_qfw；

The input of the current regulator module isi_d、i_qThe output of the current regulator module is Delaut_dAnd Δ u_q；

The output of the voltage calculation module is u_d、u_qAs a command voltage

9) Flux linkage calculation module

The input of the flux linkage calculation module is i_d、i_q、u_q，L_d(i_s、β₁T), the output is psi_f(t)，

Psi 'can be obtained from the following formula'_f(t)

ψ'_f(t) obtaining psi after filtering and amplitude limiting_f(t)

ψ_f(t) has a slicing interval of 0.8 psi_f(t₀)，1.03ψ_f(t₀)]；

10) Feedback torque calculation module

The input of the feedback torque calculation module is i_d、i_q、ψ_f(t)、ψ_f(t₀)、L_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t)；

The output of the feedback torque calculation module is T_ebThe method comprises the following steps:

T_ee1＝1.5n_pi_qψ_f(t)

in the formula, n_pIs the number of pole pairs of the motor

T_ee2＝1.5n_pi_qψ_f(t₀)

T_ee＝T_ee1-T_ee2

T_est＝1.5n_pi_q[ψ_f(t₀)+(L_d(t、i_s、β₁)-L_q(t、i_s、β₁))i_d]

T_eb＝T_ee+T_est

11) Current vector angle adjusting module

The input of the current vector angle adjustment module is T_eb、T_e ^*、β；

The output of the current vector angle adjustment module is β₁；

T_ebWith a given torque T_e ^*A torque closed-loop regulator is made, the output of the regulator is a compensation quantity delta β of a current vector angle to adjust a current angle β, and the sum of the two is β₁，

β₁＝β+Δβ

12) Pulse modulation module

The input to the modulo pulse modulation block is u_d、u_q、u_dcTheta, the output is the conduction time T of the three-phase inverter bridge IGBT_a、T_b、T_cAnd the IGBT is conducted to drive the motor to run.

2. The method for controlling the interior permanent magnet synchronous motor according to claim 1, wherein in the 6) MTPA table look-up module, a maximum torque current ratio algorithm is as follows:

per unit value i of current_bAs shown in the following formula:

wherein L is_d(t₀) And L_q(t₀) The value of the stator inductance, Ψ, respectively under nominal operating conditions_f(t₀) Is the value of the permanent magnet flux linkage under rated operating conditions,

per unit base value t of torque_ebIs represented by the following formula:

t_eb＝1.5n_pψ_f(t₀)i_b

in the formula, n_pIs the number of pole pairs of the motor,

for input torquePer unit value t divided by torque_ebObtaining a per unit torque value t_en，

i_dn、i_qnMultiplied by the current base i_bObtaining current values i of d and q axes_d、i_qI.e. i_d＝i_dn×i_b，i_q＝i_qn×i_bThen, the current amplitude i is calculated according to the following formula_sThe current vector angle β, the current vector angle,

3. the method for controlling the interior permanent magnet synchronous motor according to claim 1 or 2, wherein 7) in the stator inductance and resistance parameter table look-up module, a method for obtaining a table through a test is as follows:

firstly, under the environment of a drag test, a rotor flux linkage psi of the motor is tested under reverse drag test at rated temperature_f(t₀)；

Then the motor runs at a rated rotating speed, the tested motor is loaded, and the temperature of a winding or an iron core is tested through a temperature sensor arranged on the stator to be used as the inductance environment temperature; the rated temperature of the motor is set to be 20 ℃ and is between minus 20 ℃ and 160 DEG C]Performing a test every time the motor in the interval rises by 10 ℃, and recording the temperature t at the moment when the temperature value is stable; giving different d-axis and q-axis currents i at each test temperature point through an upper computer_d1、i_q1Recording the current regulator module output value u_d1、u_q1Measured torque T of torquemeter_e1Calculating R_s、L_d、L_qRecording motor parameters; using formula at the same time

4. The built-in permanent magnet synchronous motor control method according to claim 3, characterized in that 7) in the stator inductance and resistance parameter table look-up module, the motor parameter table look-up method comprises the following steps:

the temperature sensor collects the stator temperature t in real time, and each stator temperature t collected in real time corresponds to two table lookup temperatures t_sAnd t_s+10，t_sAnd t_s+10Is [ -20 deg.C, 160 deg.C]Two adjacent test temperature points within the interval, t being at [ t_s，t_s+10]A value of the interval;

t_s+10＝t_s+10

wherein t is_sIs integral multiple of 10, and has a value range of-20 deg.C and 160 deg.C]；

For each table lookup temperature t in the algorithm_sAll have a reference to the current amplitude i_sAngle β with current vector₁L of_dA two-dimensional table of parameters, and a value for the current amplitude i_sAngle β with current vector₁L of_qA parameter two-dimensional table; wherein i_sThe interval of the lookup table of (2) is set to 0.05 times the maximum current of β₁The angle interval of the table lookup is set to be 6 degrees; at each temperature t of table lookup_sLower, L_dAnd L_qRespectively by the real-time value of i at that moment_sAnd β₁Based on L_d、L_qThe parameter two-dimensional table is obtained by two-dimensional linear interpolation; thus looking up the table temperature t_s、t_s+10Two inductance parameters L of the d-axis inductance are obtained respectively_d(i_s、β₁、t_s)、L_d(i_s、β₁、t_s+10) And two inductance parameters L of the q-axis inductance_q(i_s、β₁、t_s)、L_q(i_s、β₁、t_s+10) Then L_d(i_s、β₁、t_s) And L_d(i_s、β₁、t_s+10)，L_q(i_s、β₁、t_s) And L_q(i_s、β₁、t_s+10) Respectively related to the temperature t according to the real-time temperature t_s，t_s+10One-dimensional linear interpolation is carried out to obtain an inductance value L corresponding to the real-time sampling temperature t_d(i_s、β₁T) and L_q(i_s、β₁、t)；

For stator resistance R_sEach real-time temperature t has two temperatures t corresponding to two lookup tables_sAnd t_s+10Temperature value R of_s(t_s)、R_s(t_s+10) Then R_s(t_s) And R_s(t_s+10) Respectively related to the temperature t according to the real-time temperature t_s、t_s+10One-dimensional linear interpolation is carried out to obtain the resistance value R corresponding to the real-time sampling temperature t_s(t)。

5. The interior permanent magnet synchronous motor control method according to claim 1 or 2, characterized in that, in 11) the current vector angle adjustment module,

ΔT_e＝T_e ^*-T_eb

Δβ＝k_pΔT_e

in the formula k_pIs a proportionality coefficient, k_pThe value of (a) is to be adjusted in the test, depending on the current i_sAnd the change of the stator temperature t of the motor is set in sections or fitted according to test data.

6. The interior permanent magnet synchronous motor control method according to claim 4, wherein, in 11) the current vector angle adjustment module,

Δβ＝k_pΔT_e

in the formula k_pIs a proportionality coefficient, k_pThe value of (a) is to be adjusted in the test, depending on the current i_sAnd the change of the stator temperature t of the motor is set in sections or fitted according to test data.

7. The interior permanent magnet synchronous motor control method according to claim 5, wherein Δ T_eHas a clipping range of [ -0.1T [)_n，0.1T_n]Wherein T is_nThe limit range of delta β is [ -5 DEG, 5 DEG ] for rated torque]；β₁Under the traction condition of the limiting range of [90 degrees ] and 180 degrees]Under the braking working condition, the angle is [180 degrees ], 270 degrees]。

8. The interior permanent magnet synchronous motor control method according to claim 6, wherein Δ T_eHas a limiting range of [ -0.05T_n，0.05T_n]Wherein T is_nThe limit range of delta β is [ -5 DEG, 5 DEG ] for rated torque]；β₁The amplitude limiting range of the traction engine is [90 degrees ],180°]under the braking working condition, the angle is [180 degrees ], 270 degrees]。

9. The method for controlling the interior permanent magnet synchronous motor according to claim 1 or 2, wherein in the 12) pulse modulation module, a multi-mode modulation strategy is adopted in a modulation algorithm, and comprises asynchronous modulation, synchronous modulation, special synchronous modulation and finally square wave control.

10. The method for controlling the interior permanent magnet synchronous motor according to claim 3, wherein in the 12) pulse modulation module, a multi-mode modulation strategy is adopted in a modulation algorithm, and the multi-mode modulation strategy comprises asynchronous modulation, synchronous modulation, special synchronous modulation and finally square wave control.

Technical Field

The invention relates to a control method of a permanent magnet synchronous motor, in particular to a control method of a built-in permanent magnet synchronous motor.

Background

The built-in permanent magnet synchronous motor is gradually and widely used in the urban transportation field of the guide rail electric car and the like due to the advantages of high power density, high power factor, high overload capacity and the like, is very important to the precision and high efficiency of torque output by a traction motor of the guide rail electric car for passenger carrying operation, and is a key for measuring the performance of a traction system. However, motor parameters of the built-in permanent magnet synchronous motor are greatly influenced by the saturation effect and the temperature change of the stator core, and the most important factor influencing the torque precision of the built-in permanent magnet synchronous motor on the trolley of the rail trolley is the motor parameter L caused by the change of the working temperature and the stator current of the motor in the running process of the motor_d、L_q、R_s、Ψ_fAnd (4) changing. The accuracy of the motor parameters of the permanent magnet synchronous motor is crucial to the control accuracy of the motor, so that the control algorithm is necessary to obtain accurate motor parameters in real time during the operation of the trolley bus. If the motor parameters cannot be accurately used in real time in the control method, the control of the permanent magnet synchronous motor is influencedAccuracy, accuracy and efficiency of the motor output torque are reduced.

The control of the permanent magnet synchronous motor is divided into an MTPA (maximum torque current ratio) control part and a flux weakening control part, if the influence of saturation effect and temperature change on motor parameters is not considered in the MTPA control, the motor cannot correctly run under an MTPA control track, and the torque output by the motor under each torque instruction has deviation.

Disclosure of Invention

The invention solves the problem that the motor parameters are not accurately used in real time in the existing permanent magnet synchronous motor control method, so that the torque precision of the motor output and the motor operation efficiency are influenced, and provides a built-in permanent magnet synchronous motor control method. The control method considers the influence of iron core magnetic saturation effect factors on motor parameters caused by the temperature change of the motor and the stator current change in the working voltage and current range of the permanent magnet synchronous motor, and provides a control method for adjusting a current vector angle by using a torque closed loop and searching and using the motor parameters on line in real time when an MTPA control mode is used, so as to improve the torque output precision of the permanent magnet synchronous motor.

The invention is realized by adopting the following technical scheme: a control method of a built-in permanent magnet synchronous motor comprises the following control modules: the device comprises a temperature sensor module, a rotary transformer module, a Clark conversion module, a Park conversion module, a torque instruction processing module, an MTPA (maximum Transmission Power Amplifier) table look-up module, a stator inductance and resistance parameter table look-up module, a voltage calculation module, a flux linkage calculation module, a feedback torque calculation module, a current vector angle adjustment module and a pulse modulation module;

1) temperature sensor module

The temperature sensor is buried in the stator of the permanent magnet synchronous motor, and the real-time stator temperature t of the motor is acquired by the temperature sensor.

2) Rotary transformer module

The rotary transformer is arranged on the permanent magnet synchronous motor, the rotor position theta of the permanent magnet synchronous motor is acquired through the rotary transformer, and the rotating speed w of the permanent magnet synchronous motor can be obtained through differentiating the rotor position theta_e。

3) Clark conversion module

The current sensor collects two-phase current of the stator to obtain i_a、i_bThen obtaining stator current i through Clark conversion_α、i_β。

4) Park conversion module

Clark transformation module to obtain i_α、i_βObtaining the current i under a d-q rotating coordinate system through Park transformation_d、i_q。

5) Torque command processing module

The input of the torque command processing module is a target torque T_e(ii) a After amplitude limiting and torque slope processing, the output of the torque command processing module is given torque

6) MTPA table look-up module

The input in the MTPA look-up table module is

The module outputs a current vector amplitude i according to a maximum torque current ratio algorithm_sAnd current vector angle β;

7) stator inductance and resistance parameter look-up table module

The input of the stator inductance and resistance parameter lookup module is a current amplitude value i_sCurrent vector angle β₁Stator temperature t, wherein current vector angle β₁Is obtained by correcting delta β output by the current vector angle adjusting module on the basis of β values obtained by the MTPA table look-up module.

The output of the stator inductance and resistance parameter lookup module is L_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t)、

Based on the temperature t and the current amplitude i of the stator of the motor_sCurrent vector angle β₁Looking up a table for an interpolation algorithm in real time to obtain a current-following amplitude i_sCurrent vector angle β₁Stator inductance L with variable stator temperature t_d(i_s、β₁、t)，L_q(i_s、β₁、t)。

Obtaining the stator resistance R changing along with the stator temperature through a real-time table look-up interpolation algorithm based on the motor temperature t_s(t)。

According to the current amplitude i_sCurrent vector angle β₁Obtaining a d-axis current set value according to the following formula

Given value of q-axis current

8) Voltage calculation module

The voltage calculation module consists of a front feed voltage module and a current regulator module.

The input of the front feed voltage module is L_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t)、ψ_f(t₀)、

Wherein the rotor flux linkage psi_f(t₀) Is at the nominal temperature; the output of the feed-forward voltage module is u_dfw、u_qfw；

The input of the current regulator module is

i_d、i_qThe output of the current regulator module is Delaut_dAnd Δ u_q；

And i_dAs a closed-loop regulator with regulator output of Deltau_d，

And i_qAs a closed-loop regulator with regulator output of Deltau_q；

The output of the voltage calculation module is u_d、u_qAs a command voltage

9) Flux linkage calculation module

In feed forward decoupling control under steady state working condition, when motor parameters of the current regulator are inaccurate, delta u output by the current regulator_dAnd Δ u_qAnd the value is a non-zero value, and voltage calculation deviation caused by inaccurate motor parameters is compensated.

Inductance and resistance parameter in calculation module for feedforward voltage uses online real-time look-up table value L_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t) high precision, and the control deviation caused by inaccurate motor parameters in the control system mainly comes from the rotor flux linkage psi_f

The input of the flux linkage calculation module is i_d、i_q、u_q，L_d(i_s、β₁T), the output is psi_f(t)，

Psi 'can be obtained from the following formula'_f(t)

ψ'_f(t) filteredAnd after clipping to obtain psi_f(t)

ψ_f(t) a slice interval of

10) Feedback torque calculation module

The input of the feedback torque calculation module is i_d、i_q、ψ_f(t)、ψ_f(t₀)、L_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t)；

The output of the feedback torque calculation module is T_ebThe method comprises the following steps:

T_ee1＝1.5n_pi_qψ_f(t)

in the formula, n_pIs the number of pole pairs of the motor

T_ee2＝1.5n_pi_qψ_f(t₀)

T_ee＝T_ee1-T_ee2

T_est＝1.5n_pi_q[ψ_f(t₀)+(L_d(t、i_s、β₁)-L_q(t、i_s、β₁))i_d]

T_eb＝T_ee+T_est

11) Current vector angle adjusting module

The input of the current vector angle adjustment module is T_eb、T_e ^*、β。

The output of the current vector angle adjustment module is β₁。

T_ebWith a given torque T_e ^*A torque closed-loop regulator is made, the output of the regulator is a compensation quantity delta β of a current vector angle to adjust a current angle β, and the sum of the two is β₁，

β₁＝β+Δβ

12) Pulse modulation module

The input to the modulo pulse modulation block is u_d、u_q、u_dcTheta, the output is the conduction time T of the three-phase inverter bridge IGBT_a、T_b、T_cAnd the IGBT is conducted to drive the motor to run.

The invention has the following beneficial effects:

(1) the method simultaneously considers the influence of temperature change and motor saturation effect on the motor parameters on line, improves the accuracy of the motor parameters at each working point, and ensures that the permanent magnet synchronous motor can still maintain high control precision under wide environmental conditions;

(2) the invention is based on the motor temperature t and the current amplitude i on a feedforward channel_sCurrent vector angle β on-line real-time table look-up and MTPA real-time table look-up, flux linkage is calculated in real time by using flux linkage calculation model on feedback channel

A detection device for the temperature of the rotor is omitted; and the d-axis current is redistributed by the output result of the torque closed loop

And q-axis currentThe permanent magnet synchronous motor is maintained to run according to the MTPA track, and the heating and the loss of the motor are reduced.

(3) The algorithm of the invention can improve the output precision and stability of the torque, and improve the efficiency of the permanent magnet synchronous motor and the running performance of the guide rail electric car.

Drawings

FIG. 1 is a general diagram of a control method according to the present invention;

fig. 2 is a current vector diagram of the permanent magnet synchronous motor according to the present invention;

FIG. 3 is a table look-up flow chart of the parameters of the inductance and the resistance of the permanent magnet synchronous motor according to the present invention;

FIG. 4 is a control block diagram of the flux linkage calculation module according to the present invention;

FIG. 5 is a block diagram of the current vector angle adjustment control of the present invention;

fig. 6 is a block diagram of a multi-mode modulation strategy according to the present invention.

Detailed Description

A control method of an interior permanent magnet synchronous motor comprises the following control modules (as shown in figure 1): the device comprises a temperature sensor module 1, a rotary transformer module 2, a Clark conversion module 3, a Park conversion module 4, a torque instruction processing module 5, an MTPA table look-up module 6, a stator inductance and resistance parameter table look-up module 7, a voltage calculation module, a flux linkage calculation module 9, a feedback torque calculation module 10, a current vector angle adjustment module 11 and a pulse modulation module 12;

1) temperature sensor module

The temperature sensor is buried in the stator of the permanent magnet synchronous motor, and the real-time stator temperature t of the motor is acquired by the temperature sensor.

2) Rotary transformer module

The rotary transformer is arranged on the permanent magnet synchronous motor, the rotor position theta of the permanent magnet synchronous motor is acquired through the rotary transformer, and the rotating speed w of the permanent magnet synchronous motor can be obtained through differentiating the rotor position theta_e。

3) Clark conversion module

The current sensor collects two-phase current of the stator to obtain i_a、i_bThen obtaining stator current i through Clark conversion_α、i_β。

4) Park conversion module

Clark transformation module to obtain i_α、i_βObtaining the current i under a d-q rotating coordinate system through Park transformation_d、i_q。

5) Torque command processing module

The input of the torque command processing module is a target torque T_eIts value is derived from the VCU control unit; after amplitude limiting and torque slope processing, the output of the torque command processing module is given torque

6) MTPA table look-up module

The MTPA table look-up module is realized by selecting parameters of rated points of the motor, and the input of the MTPA table look-up module is

The module outputs a current vector amplitude i according to a maximum torque current ratio algorithm_sAnd current vector angle β;

the maximum torque current ratio algorithm is specifically as follows:

per unit value i of current_bAs shown in the following formula:

wherein L is_d(t₀) And L_q(t₀) The value psi of the stator inductance under the rated working condition_f(t₀) Is the value of the permanent magnet flux linkage under rated operating conditions,

per unit base value t of torque_ebIs represented by the following formula:

t_eb＝1.5n_pψ_f(t₀)i_b

in the formula, n_pIs the number of pole pairs of the motor,

for input torque

Per unit value t divided by torque_ebObtaining a per unit torque value t_en，

Constructing a t according to the algorithm of the maximum torque current ratio_enAnd d-axis current per unit value i_dnFor each table using a one-dimensional interpolation table look-up algorithm

All correspond to an i_dnCalculating to obtain a q-axis current per unit value i according to the following formula_qn，

i_dn、i_qnMultiplied by the current base i_bObtaining current values i of d and q axes_d、i_qI.e. i_d＝i_dn×i_b，i_q＝i_qn×i_bThen, the current amplitude i is calculated according to the following formula_sCurrent vector angle β, as shown in FIG. 2, due to i_bWhen the fixed motor parameters are used in calculation, the analyzed β value is inaccurate, and the β value is corrected in a current vector angle adjustment link.

7) Stator inductance and resistance parameter look-up table module

The temperature change of the motor can cause the winding resistance R_sInfluence winding loss, control algorithm R_sThe variation affects the resistive voltage drop. R of permanent magnet synchronous motor on trolley bus_sGreater value, R_sThe effect of the variation is not negligible.

The variation of the stator current can cause the magnetic saturation effect of the stator core, resulting in the stator inductance L_d、L_qThe value of (c) is changed. Temperature affects the rotor permanent magnet flux linkage Ψ_fThe saturation of d-axis and q-axis can be changed by the change of flux linkage, in addition, the magnetic permeability of the motor silicon steel sheet can be reduced along with the rise of temperature, and the saturation of the inductor can be influenced by the change of the magnetic permeability of the motor iron core material, so that L_dAnd L_qWill vary as a function of temperature and current.

The input of the inductance and resistance parameter look-up table module is a current amplitude value i_sCurrent vector angle β₁Stator temperature t, wherein current vector angle β₁The torque precision correction method is characterized in that motor output torque precision reduction factors caused by motor parameter change, sampling delay and the like are considered, and the correction is obtained by delta β output by a torque closed-loop algorithm module on the basis of β values obtained by an MTPA table look-up module.

The output of the stator inductance and resistance parameter lookup module is L_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t)、

Based on the temperature t and the current amplitude i of the stator of the motor_sCurrent vector angle β₁Looking up a table for an interpolation algorithm in real time to obtain a current-following amplitude i_sCurrent vector angle β₁Stator inductance L with variable stator temperature t_d(i_s、β₁、t)，L_q(i_s、β₁、t)。

Stator resistance R_sThe influence of current is small, the influence of temperature is mainly used, and the stator resistance R changing along with the temperature of the stator is obtained through a real-time table look-up interpolation algorithm based on the temperature t of the motor_s(t)。

According to the current amplitude i_sCurrent vector angle β₁Obtaining a d-axis current set value according to the following formula

Given value of q-axis current

Wherein L is determined_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_sThe table of (t) may use motor designThe parameter table provided by the personnel can also be obtained through tests, and the method for obtaining the table through the tests is as follows:

firstly, under the environment of a drag test, the rotor flux linkage psi of the motor is tested under the condition of reverse drag at rated temperature_f(t₀)。

And then the motor runs at a rated rotating speed, the tested motor is loaded, and the temperature of the winding or the iron core is tested through a temperature sensor arranged on the stator to be used as the inductance environment temperature. The rated temperature of the motor is set to be 20 ℃ and is between minus 20 ℃ and 160 DEG C]Performing a test every time the motor in the interval rises by 10 ℃, and recording the temperature t at the moment when the temperature value is stable; giving different d-axis and q-axis currents i at each test temperature point (nineteen temperature points in total) through an upper computer_d1、i_q1Recording the current regulator module output value u_d1、u_q1Measured torque T of torquemeter_e1Calculating R_s、L_d、L_qRecording motor parameters; using formula at the same timeCalculating the current amplitude i_sBy the formula

Calculating current vector angle β, and respectively drawing L_d、L_qAbout i_sAnd β, there is one L for each test temperature point t_dTwo-dimensional table of (1) and L_qA two-dimensional table of (1); a plurality of L_dAnd L_qThe two-dimensional table of (1) is written in the program in the form of an array; r exists at each test temperature point t_sThe one-dimensional table about t is written in the program in the form of a one-dimensional array for use in queries.

The motor parameter table look-up method comprises the following steps:

the temperature sensor collects the stator temperature t in real time, and each stator temperature t collected in real time corresponds to two table lookup temperatures t_sAnd t_s+10，t_sAnd t_s+10Is [ -20 deg.C, 160 deg.C]Two adjacent test temperature points within the interval, t being at [ t_s，t_s+10]A value of the interval;

t_s+10＝t_s+10

wherein t is_sIs integral multiple of 10, and has a value range of-20 deg.C and 160 deg.C]。

For each table lookup temperature t in the algorithm_sAll have a reference to the current amplitude i_sAngle β with current vector₁L of_dA two-dimensional table of parameters, and a value for the current amplitude i_sAngle β with current vector₁L of_qA parameter two-dimensional table; wherein i_sThe interval of the lookup table of (2) is set to 0.05 times the maximum current of β₁The angle interval of the table lookup is set to be 6 degrees; at each temperature t of table lookup_sLower, L_dAnd L_qRespectively by the real-time value of i at that moment_sAnd β₁Based on L_d、L_qAnd the parameter two-dimensional table is obtained by two-dimensional linear interpolation. Thus looking up the table temperature t_s、t_s+10Two inductance parameters L of the d-axis inductance are obtained respectively_d(i_s、β₁、t_s)、L_d(i_s、β₁、t_s+10) And two inductance parameters L of the q-axis inductance_q(i_s、β₁、t_s)、L_q(i_s、β₁、t_s+10) Then L_d(i_s、β₁、t_s) And L_d(i_s、β₁、t_s+10)，L_q(i_s、β₁、t_s) And L_q(i_s、β₁、t_s+10) Respectively related to the temperature t according to the real-time temperature t_s，t_s+10One-dimensional linear interpolation is carried out to obtain an inductance value L corresponding to the real-time sampling temperature t_d(i_s、β₁T) and L_q(i_s、β₁T), the flow chart is shown in FIG. 3;

for stator resistance R_sEach real-time temperature t has two temperatures t corresponding to two lookup tables_sAnd t_s+10Temperature value R of_s(t_s)、R_s(t_s+10) Then R_s(t_s) And R_s(t_s+10) Respectively related to the temperature t according to the real-time temperature t_s、t_s+10One-dimensional linear interpolation is carried out to obtain the resistance value R corresponding to the real-time sampling temperature t_s(t)。

8) Voltage calculation module

The voltage calculation module consists of a feedforward voltage module 8 and a current regulator module.

The input of the front feed voltage module is L_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t)、ψ_f(t₀)、

In which the rotor flux linkage Ψ_f(t0)Is at the nominal temperature; the output of the feed-forward voltage module is u_dfw、u_qfw；

The input of the current regulator module is

i_d、i_qThe output of the current regulator module is Delaut_dAnd Δ u_q；

And i_dAs a closed-loop regulator with regulator output of Deltau_d，

And i_qAs a closed-loop regulator with regulator output of Deltau_q；

The output of the voltage calculation module is u_d、u_qAs a command voltage

9) Flux linkage calculation module

The permanent magnet material in the permanent magnet synchronous motor rotor is greatly influenced by temperature change, the guide rail electric car permanent magnet synchronous motor rotor is particularly sensitive to temperature by selecting the rubidium, iron and boron material, and the residual magnetism B of the magnet material is generated during the temperature change_rAnd intrinsic coercive force H_icThe change occurs and the relationship between the remanence of the magnet material and the temperature is shown in the following formula.

Wherein t is₀Is rated temperature, in the invention, the rated temperature of the motor is set at 20 ℃, t is the actual working temperature of the permanent magnet, B_r0Is the remanence of the magnet at the rated temperature, B_rtIs the remanence of the permanent magnet under the actual working temperature, α is the temperature coefficient of the remanence, the motor rotor flux linkage and the motor remanence have the following relationship,

ψ_f(t)＝∫B_rtdA

where a is a region through which the flux linkage passes, the relationship between the motor flux linkage and the temperature change is as follows

ψ_f(t₀) Is the rotor flux linkage at rated temperature,. psi_fAnd (t) is the rotor flux linkage at the actual operating temperature of the motor.

Permanent magnets mounted in the rotor of the machine psi_f(t) is difficult to measure under the condition that the motor runs, and the real-time flux linkage value psi is calculated by adopting a flux linkage calculation model in the invention_f(t)。

In feed forward decoupling control under steady state working condition, when motor parameters of the current regulator are inaccurate, delta u output by the current regulator_dAnd Δ u_qAnd the value is a non-zero value, and voltage calculation deviation caused by inaccurate motor parameters is compensated.

Inductance and resistance parameter in calculation module for feedforward voltage uses online real-time look-up table value L_d(i_s、β₁、t)、L_q(i_s、β₁、t)、R_s(t) high precision, and the control deviation caused by inaccurate motor parameters in the control system mainly comes from the rotor flux linkage psi_f

The input of the flux linkage calculation module is i_d、i_q、u_q，L_d(i_s、β₁T), the output is psi_f(t)，

Psi 'can be obtained from the following formula'_f(t)

ψ'_f(t) obtaining psi after filtering and amplitude limiting_f(t)

ψ_f(t) a slice interval of

10) Feedback torque calculation module

The motor torque is composed of an excitation torque and a reluctance torque, wherein the excitation torque is related to the rotor flux linkage and is independent of the inductance, so that the calculated flux linkage ψ can be used_f(T) calculating the excitation torque T_ee1Using rotor flux linkage psi at rated temperature_f(t₀) Calculating the excitation torque T_ee2The difference T between the two_eeAs a deviation of the excitation torque exerted when the rotor flux linkage changes due to a change in temperature; meanwhile, the electromagnetic torque T of the motor is calculated according to inductance parameters obtained by table lookup_est，T_eeAnd T_estThe sum is used as the feedback torque T of the motor_eb。

The input of the feedback torque calculation module is i_d、i_q、ψ_f(t)、ψ_f(t₀)、L_d(i_s、β₁、t)、L_d(i_s、β₁、t)、R_s(t)

The output of the feedback torque calculation module is T_ebThe method comprises the following steps:

T_ee1＝1.5n_pi_qψ_f(t)

in the formula, n_pIs the number of pole pairs of the motor

T_ee2＝1.5n_pi_qψ_f(t₀)

T_ee＝T_ee1-T_ee2

T_est＝1.5n_pi_q[ψ_f(t₀)+(L_d(t、i_s、β₁)-L_q(t、i_s、β₁))i_d]

T_eb＝T_ee+T_est

11) Current vector angle adjusting module

The MTPA control current track is determined by motor parameters as shown in the following formula, and because the motor parameters are influenced by temperature and saturation continuously during the operation of the permanent magnet synchronous motor, the motor current vector angle β calculated in the MTPA table look-up module according to the fixed motor parameters is usually inaccurate, so that i_sDistributing command current to d and q axesAndinaccuracy results in the motor not being in the MTPA state during actual operation, which reduces the accuracy of the torque output by the motor, and therefore the current vector angle β needs to be adjusted,

the input of the current vector angle adjustment module is T_eb、T_e ^*、β。

The output of the current vector angle adjustment module is β₁。

T_ebWith a given torque T_e ^*Making a torque closed-loop regulator, the regulator output is the compensation quantity delta β of the current vector angle to regulate electricityFlow angle β, sum of which is β₁As shown in fig. 5, the following equation is shown.

β₁＝β+Δβ

Correction of current vector angle is aimed at realizing non-static tracking of feedback torque to given torque and raising control accuracy of torque, but the torque output accuracy of motor can not be up to 100%, and given torque T_e ^*And between feedback_ebThere will always be a static error, so the torque closed-loop regulator is only provided with a proportional link, as shown in the following formula

Δβ＝k_pΔT_e

In the formula k_pIs a proportionality coefficient, k_pThe value of (a) is to be adjusted in the test, depending on the current i_sAnd the change of the stator temperature t of the motor is set in sections or fitted according to test data. k is a radical of_pHas a value range of [ -0.03, 0.03 [)]

ΔT_eHas a limiting range of [ -0.05T_n，0.05T_n]Wherein T is_nIs the rated torque.

The clipping range of Δ β is [ -5 °, 5 ° ].

β₁Under the traction condition of the limiting range of [90 degrees ] and 180 degrees]Under the braking working condition, the angle is [180 degrees ], 270 degrees]。

12) Pulse modulation module

The guide rail electric car traction system belongs to a high-power electric transmission system and is mainly characterized by high voltage and high current, the peak power of a motor reaches 360kW and is limited by heat dissipation conditions, the switching frequency of an IGBT is only 900Hz at most, but the output frequency of an inverter can reach 300Hz at most, the traditional svpwm modulation algorithm cannot meet the requirements, and the modulation algorithm adopts a multi-mode modulation strategy, as shown in figure 6, the multi-mode modulation strategy comprises asynchronous modulation, synchronous modulation, special synchronous modulation and finally square wave control, and the utilization rate of bus voltage is improved.

The input to the modulo pulse modulation block is u_d、u_q、u_dcTheta, the output is the conduction time T of the three-phase inverter bridge IGBT_a、T_b、T_cAnd the IGBT is conducted to drive the motor to run.