Redundancy control system and method suitable for surface-mounted permanent magnet synchronous motor
阅读说明：本技术 适用于表贴式永磁同步电机的冗余控制系统及方法 (Redundancy control system and method suitable for surface-mounted permanent magnet synchronous motor ) 是由 鲍洁秋 王书礼 王森 于 2021-07-28 设计创作，主要内容包括：本发明属为一种适用于表贴式永磁同步电机的冗余控制系统及方法,包括：速度及位置监测模块,用于获得电机a相轴线的夹角和电机角速度；速度及位置估算模块,用于当速度及位置监测模块检测不到电机a相轴线的夹角和电机角速度；获取电机a相轴线的夹角和电机角速度的估算值；信号处理与生成单元,用于根据速度及位置监测模块的检测值或速度及位置估算模块的估算值生成控制信号；切换单元,当检测到所述速度及位置监测模块检测不到电机的位置及转速信息时,将所述速度及位置监测模块切换为速度及位置估算模块与所述信号采集与生成单元连接。解决永磁同步电机运行过程中因机械位置信号丢失而导致电机停机,危机设备运行安全等问题。(The invention belongs to a redundancy control system and method suitable for a surface-mounted permanent magnet synchronous motor, comprising the following steps: the speed and position monitoring module is used for obtaining the included angle of the phase axis of the motor a and the angular speed of the motor; the speed and position estimation module is used for detecting the included angle of the phase axis of the motor a and the angular speed of the motor when the speed and position monitoring module cannot detect the included angle of the phase axis of the motor a and the angular speed of the motor; obtaining an included angle of a phase axis of a motor a and an estimated value of the angular speed of the motor; the signal processing and generating unit is used for generating a control signal according to the detection value of the speed and position monitoring module or the estimation value of the speed and position estimation module; and the switching unit is used for switching the speed and position monitoring module into a speed and position estimation module to be connected with the signal acquisition and generation unit when the speed and position monitoring module is detected to be incapable of detecting the position and rotating speed information of the motor. The problems that the motor is stopped due to the loss of mechanical position signals in the running process of the permanent magnet synchronous motor, the running safety of crisis equipment is high and the like are solved.)
1. A redundant control system adapted for a surface-mount permanent magnet synchronous motor, the system comprising:
a speed and position monitoring module for obtaining the included angle theta of the phase axis of the motor a and the angular speed omega of the motorr；
A speed and position estimation module for estimating the angular speed omega of the motor and the included angle theta of the phase axis of the motor a when the speed and position monitoring module can not detectr(ii) a Obtaining the included angle theta of the phase axis of the motor a and the angular velocity omega of the motorrAn estimate of (d);
the signal processing and generating unit is used for generating a control signal according to the detection value of the speed and position monitoring module or the estimation value of the speed and position estimation module;
and the switching unit is used for switching the speed and position monitoring module into a speed and position estimation module to be connected with the signal acquisition and generation unit when the speed and position monitoring module is detected to be incapable of detecting the position and rotating speed information of the motor.
2. The system of claim 1, wherein the signal processing and generation unit comprises:
the current acquisition module is used for acquiring three-phase input current of the motor;
the Clarke conversion module is used for converting the three-phase input current of the current acquisition module into two-phase quadrature axis current;
the Park conversion module is used for converting the two-phase quadrature axis current into a direct axis current under a two-phase rotating coordinate system according to the detection value of the speed and position monitoring module or the estimation value of the speed and position estimation module;
the speed conversion module is used for obtaining a given current of a q axis according to the rotating speed of a given motor and the detection value of the speed and position monitoring module or the motor angular speed in the estimation value of the speed and position estimation module;
the current conversion module is used for obtaining direct-axis voltage and quadrature-axis voltage of the motor according to the direct-axis current output by the Park conversion module under the two-phase rotating coordinate system, the given current of the speed conversion module and the conversion current;
the Park inverse transformation module is used for converting direct-axis voltage and quadrature-axis voltage of the motor into quadrature-axis voltage;
and the SVPWM signal generator acquires an SVPWM signal required by the motor controller according to the quadrature axis voltage and the switching sequence comparison table, triggers an IGBT in the inverse transformation module of the motor controller, and the inverse transformation module outputs three-phase alternating current required by the permanent magnet synchronous motor according to the trigger signal.
3. The system of claim 2, wherein upon the speed and position monitoring module failing to detect a detection value,
acquiring three-phase input current of a motor acquired by a current acquisition module in a sampling period before a mechanical position fails;
converting the three-phase input current into a three-phase voltage value;
converting the three-phase voltage value into a two-phase voltage value;
obtaining two-phase voltage values of the permanent magnet synchronous motor stator under an alpha and beta two-phase coordinate system according to the two-phase voltage values, wherein the two-phase voltage values of the permanent magnet synchronous motor stator under the alpha and beta two-phase coordinate system meet the conditions:
wherein the content of the first and second substances,andcurrent values of a sampling period before the mechanical position sensor fails are respectively obtained;the motor speed of the sampling period before the mechanical position sensor fails,andis a two-phase voltageAnd
calculating the satisfaction condition of the two-phase voltage value to obtain the motor rotor angle theta of the sampling period before the mechanical position sensor fails[0]And motor speed
Correcting the included angle theta of the phase axis of the motor a in the fault through the following formula[m]：
Wherein, TPIs a sampling period; m is 1,2,3 …, n-1, n, whereinωmaxIs the maximum angular velocity of the motor.
4. The system of claim 3, wherein converting the three-phase input current to three-phase voltage values and converting the three-phase voltage values to two-phase voltage values comprises:
the voltage loop equation of the three-phase winding of the permanent magnet synchronous motor stator can be expressed as
Wherein u isa、ubAnd ucRespectively the voltage of each phase of the motor; ra、RbAnd RcIs the phase resistance of the motor stator; l isa、LbAnd LcRespectively the winding self-inductance of the motor; mabAnd MbaThe phase windings of the motor a and the phase b are mutually inductive; macAnd McaThe phase a of the motor is mutually inducted by the phase c windings; mbcAnd McbThe phase b of the motor is mutually inducted by the phase c windings;
for a surface-mounted three-phase permanent magnet synchronous motor, a three-phase symmetrical winding space structure is generally adopted, and the inductance, the resistance and the current of the surface-mounted three-phase permanent magnet synchronous motor meet the following relations:
get LeIs L-M, available as
According to the principle that the amplitudes before and after conversion are equal, two-phase voltages are obtained in a sampling period before a fault occurs at a mechanical positionAndis shown as
Wherein the content of the first and second substances,andthe three-phase voltage values of a sampling period before the mechanical position sensor fails are respectively obtained.
5. The system of claim 3, wherein θ[m]The optimal motor rotor angle of (a) is expressed as:
θ[m]＝θopt＝θ+mΔθ，m＝1,2,3,…,n
s.t
wherein, thetaoptThe rotor angle of the motor is optimal; i.e. iq_optIs an optimum of iqThe current is applied.
6. A redundancy control method suitable for a surface-mounted permanent magnet synchronous motor is characterized by comprising the following steps:
obtaining the included angle theta of the phase axis of the motor a and the angular velocity omega of the motorr；
When the included angle theta of the phase axis of the motor a and the angular speed omega of the motor are not detectedrWhen the current is over;
obtaining the included angle theta of the phase axis of the motor a and the angular velocity omega of the motorrAn estimate of (d);
according to the included angle theta of the phase axis of the motor a and the angular speed omega of the motorrOr the included angle theta of the phase axis of the motor a and the angular speed omega of the motorrGenerates a control signal.
7. Method according to claim 6, characterized in that the angle θ between the axes of the phases of the motor a and the angular velocity ω of the motor are determined as a function ofrOr the included angle theta of the phase axis of the motor a and the angular speed omega of the motorrGenerating a control signal comprising:
collecting three-phase input current of a motor;
converting three-phase input current into two-phase quadrature axis current;
converting two-phase quadrature axis current into direct axis current under a two-phase rotating coordinate system according to the included angle theta or the estimated value of the rotor magnetic pole and the phase axis of the motor a;
obtaining a given current of a q axis according to a given motor rotating speed, a motor angular speed or an estimated value of the motor angular speed;
obtaining direct-axis voltage and quadrature-axis voltage of the motor according to the direct-axis current, the given current and the conversion current under the two-phase rotating coordinate system;
converting direct-axis voltage and quadrature-axis voltage of the motor into quadrature-axis voltage;
and obtaining an SVPWM signal required by the motor controller according to the quadrature axis voltage and the switch sequence comparison table, triggering an IGBT in an inverse transformation module of the motor controller, and outputting three-phase alternating current required by the permanent magnet synchronous motor according to the triggering signal by the inverse transformation module.
8. Method according to claim 6, characterized in that the angle θ between the axes of the phases of the motor a and the angular velocity ω of the motor are obtainedrThe estimated values of (a) include:
acquiring three-phase input current of a motor acquired by a current acquisition module in a sampling period before a mechanical position fails;
converting the three-phase input current into a three-phase voltage value;
converting the three-phase voltage value into a two-phase voltage value;
obtaining two-phase voltage values of the permanent magnet synchronous motor stator under an alpha and beta two-phase coordinate system according to the two-phase voltage values, wherein the two-phase voltage values of the permanent magnet synchronous motor stator under the alpha and beta two-phase coordinate system meet the conditions:
wherein the content of the first and second substances,andcurrent values of a sampling period before the mechanical position sensor fails are respectively obtained;the motor speed of the sampling period before the mechanical position sensor fails,andis a two-phase voltageAnd
calculating the satisfaction condition of the two-phase voltage value to obtain the motor rotor angle theta of the sampling period before the mechanical position sensor fails[0]And motor speed
Correcting the included angle theta of the phase axis of the motor a in the fault through the following formula[m]：
Wherein, TPIs a sampling period; m is 1,2,3 …, n-1, n, whereinωmaxIs the maximum angular velocity of the motor.
9. The method of claim 6, wherein converting the three-phase input current to three-phase voltage values and converting the three-phase voltage values to two-phase voltage values comprises:
the voltage loop equation of the three-phase winding of the permanent magnet synchronous motor stator can be expressed as
Wherein u isa、ubAnd ucRespectively the voltage of each phase of the motor; ra、RbAnd RcIs the phase resistance of the motor stator; l isa、LbAnd LcRespectively the winding self-inductance of the motor; mabAnd MbaThe phase windings of the motor a and the phase b are mutually inductive; macAnd McaThe phase a of the motor is mutually inducted by the phase c windings; mbcAnd McbThe phase b of the motor is mutually inducted by the phase c windings;
for a surface-mounted three-phase permanent magnet synchronous motor, a three-phase symmetrical winding space structure is generally adopted, and the inductance, the resistance and the current of the surface-mounted three-phase permanent magnet synchronous motor meet the following relations:
get LeIs L-M, available as
According to the principle that the amplitudes before and after conversion are equal, two-phase voltages are obtained in a sampling period before a fault occurs at a mechanical positionAndis shown as
Wherein the content of the first and second substances,andthe three-phase voltage values of a sampling period before the mechanical position sensor fails are respectively obtained.
10. The method of claim 6, wherein θ[m]The optimal motor rotor angle of (a) is expressed as:
θ[m]＝θopt＝θ+mΔθ，m＝1,2,3,…,n
s.t
wherein, thetaoptThe rotor angle of the motor is optimal; i.e. iq_optIs an optimum of iqThe current is applied.
Technical Field
The invention belongs to the technical field of permanent magnet synchronous motors, and particularly relates to a redundancy control system and method suitable for a surface-mounted permanent magnet synchronous motor.
Background
The permanent magnet synchronous motor is widely applied to the fields of aviation, aerospace, transportation, industry, agriculture and the like by the advantages of simple structure, small volume, light weight, high energy density and the like, in order to ensure the high efficiency, high precision and stability of the control of the permanent magnet synchronous motor, the control mode of the permanent magnet synchronous motor can be generally divided into two types of control with a position sensor and control without the position sensor, the two control methods have the advantages and the disadvantages respectively, the control with the position sensor of the motor needs to be matched with the mechanical position sensor of the motor for use, compared with the control without the position sensor, the control with the position sensor can track the position and speed information of the motor in real time, thereby ensuring the control precision of the motor, improving the efficiency of the motor and reducing the heating value of the motor, the mechanical position sensor of the motor not only increases the volume and the cost of the motor, but also reduces the reliability of the system operation, thereby limiting the application in the fields with higher reliability requirements such as aviation, aerospace, transportation and the like.
The surface-mounted permanent magnet synchronous motor is used as one of permanent magnet synchronous motors, the processing structure is simple, the cost is low, the surface-mounted permanent magnet synchronous motor is widely popularized in aviation, aerospace, traffic, industry and agriculture, the position sensor permanent magnet synchronous motor realizes the monitoring of motor position signals by mounting a mechanical position sensor at the end part of the motor, the working state of the mechanical position sensor directly influences the running state of the motor, once the mechanical position sensor fails, the motor position signals are lost, the motor is caused to have shutdown faults, and the running safety of crisis equipment is ensured.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a redundancy control method suitable for a surface-mounted permanent magnet synchronous motor, and solve the problems of motor halt, crisis equipment operation safety and the like caused by loss of mechanical position signals in the operation process of the permanent magnet synchronous motor.
The present invention is achieved in such a way that,
a redundant control system for a surface-mount permanent magnet synchronous motor, the system comprising:
a speed and position monitoring module for obtaining the included angle theta of the phase axis of the motor a and the angular speed omega of the motorr；
A speed and position estimation module for estimating the angular speed omega of the motor and the included angle theta of the phase axis of the motor a when the speed and position monitoring module can not detectr(ii) a Obtaining the included angle theta of the phase axis of the motor a and the angular velocity omega of the motorrAn estimate of (d);
the signal processing and generating unit is used for generating a control signal according to the detection value of the speed and position monitoring module or the estimation value of the speed and position estimation module;
and the switching unit is used for switching the speed and position monitoring module into a speed and position estimation module to be connected with the signal acquisition and generation unit when the speed and position monitoring module is detected to be incapable of detecting the position and rotating speed information of the motor.
Further, the signal processing and generating unit includes:
the current acquisition module is used for acquiring three-phase input current of the motor;
the Clarke conversion module is used for converting the three-phase input current of the current acquisition module into two-phase quadrature axis current;
the Park conversion module is used for converting the two-phase quadrature axis current into a direct axis current under a two-phase rotating coordinate system according to the detection value of the speed and position monitoring module or the estimation value of the speed and position estimation module;
the speed conversion module is used for obtaining a given current of a q axis according to the rotating speed of a given motor and the detection value of the speed and position monitoring module or the motor angular speed in the estimation value of the speed and position estimation module;
the current conversion module is used for obtaining direct-axis voltage and quadrature-axis voltage of the motor according to the direct-axis current output by the Park conversion module under the two-phase rotating coordinate system, the given current of the speed conversion module and the conversion current;
the Park inverse transformation module is used for converting direct-axis voltage and quadrature-axis voltage of the motor into quadrature-axis voltage;
and the SVPWM signal generator acquires an SVPWM signal required by the motor controller according to the quadrature axis voltage and the switching sequence comparison table, triggers an IGBT in the inverse transformation module of the motor controller, and the inverse transformation module outputs three-phase alternating current required by the permanent magnet synchronous motor according to the trigger signal.
Furthermore, when the speed and position monitoring module can not detect the detection value,
acquiring three-phase input current of a motor acquired by a current acquisition module in a sampling period before a mechanical position fails;
converting the three-phase input current into a three-phase voltage value;
converting the three-phase voltage value into a two-phase voltage value;
obtaining two-phase voltage values of the permanent magnet synchronous motor stator under an alpha and beta two-phase coordinate system according to the two-phase voltage values, wherein the two-phase voltage values of the permanent magnet synchronous motor stator under the alpha and beta two-phase coordinate system meet the conditions:
wherein the content of the first and second substances,andcurrent values of a sampling period before the mechanical position sensor fails are respectively obtained;the motor speed of the sampling period before the mechanical position sensor fails,andis a two-phase voltageAnd
calculating the satisfaction condition of the two-phase voltage value to obtain the motor rotor angle theta of the sampling period before the mechanical position sensor fails[0]And motor speed
Correcting the included angle theta of the phase axis of the motor a in the fault through the following formula[m]：
Wherein, TPIs a sampling period; m is 1,2,3 …, n-1, n, whereinωmaxIs the maximum angular velocity of the motor.
Further, converting the three-phase input current into three-phase voltage values, the converting the three-phase voltage values into two-phase voltage values includes:
the voltage loop equation of the three-phase winding of the permanent magnet synchronous motor stator can be expressed as
Wherein u isa、ubAnd ucRespectively the voltage of each phase of the motor; ra、RbAnd RcIs the phase resistance of the motor stator; l isa、LbAnd LcRespectively the winding self-inductance of the motor; mabAnd MbaFor winding a phase and b phase of motorGroup mutual inductance; macAnd McaThe phase a of the motor is mutually inducted by the phase c windings; mbcAnd McbThe phase b of the motor is mutually inducted by the phase c windings;
for a surface-mounted three-phase permanent magnet synchronous motor, a three-phase symmetrical winding space structure is generally adopted, and the inductance, the resistance and the current of the surface-mounted three-phase permanent magnet synchronous motor meet the following relations:
get LeIs L-M, available as
According to the principle that the amplitudes before and after conversion are equal, two-phase voltages are obtained in a sampling period before a fault occurs at a mechanical positionAndis shown as
Wherein the content of the first and second substances,andthe three-phase voltage values of a sampling period before the mechanical position sensor fails are respectively obtained.
Further, θ[m]The optimal motor rotor angle of (a) is expressed as:
θ[m]＝θopt＝θ+mΔθ，m＝1,2,3,…,n
s.t
wherein, thetaoptThe rotor angle of the motor is optimal; i.e. iq_optIs an optimum of iqThe current is applied.
A redundancy control method suitable for a surface-mounted permanent magnet synchronous motor comprises the following steps:
obtaining the included angle theta of the phase axis of the motor a and the angular velocity omega of the motorr；
When the included angle theta of the phase axis of the motor a and the angular speed omega of the motor are not detectedrWhen the current is over;
obtaining the included angle theta of the phase axis of the motor a and the angular velocity omega of the motorrAn estimate of (d);
according to the included angle theta of the phase axis of the motor a and the angular speed omega of the motorrOr the included angle theta of the phase axis of the motor a and the angular speed omega of the motorrGenerates a control signal.
Further, according to the included angle theta of the phase axis of the motor a and the angular speed omega of the motorrOr the included angle theta of the phase axis of the motor a and the angular speed omega of the motorrGenerating a control signal comprising:
collecting three-phase input current of a motor;
converting three-phase input current into two-phase quadrature axis current;
converting two-phase quadrature axis current into direct axis current under a two-phase rotating coordinate system according to the included angle theta or the estimated value of the rotor magnetic pole and the phase axis of the motor a;
obtaining a given current of a q axis according to a given motor rotating speed, a motor angular speed or an estimated value of the motor angular speed;
obtaining direct-axis voltage and quadrature-axis voltage of the motor according to the direct-axis current, the given current and the conversion current under the two-phase rotating coordinate system;
converting direct-axis voltage and quadrature-axis voltage of the motor into quadrature-axis voltage;
and obtaining an SVPWM signal required by the motor controller according to the quadrature axis voltage and the switch sequence comparison table, triggering an IGBT in an inverse transformation module of the motor controller, and outputting three-phase alternating current required by the permanent magnet synchronous motor according to the triggering signal by the inverse transformation module.
Further, an included angle theta of a phase axis of the motor a and a motor angular velocity omega are obtainedrThe estimated values of (a) include:
acquiring three-phase input current of a motor acquired by a current acquisition module in a sampling period before a mechanical position fails;
converting the three-phase input current into a three-phase voltage value;
converting the three-phase voltage value into a two-phase voltage value;
obtaining two-phase voltage values of the permanent magnet synchronous motor stator under an alpha and beta two-phase coordinate system according to the two-phase voltage values, wherein the two-phase voltage values of the permanent magnet synchronous motor stator under the alpha and beta two-phase coordinate system meet the conditions:
wherein the content of the first and second substances,andcurrent values of a sampling period before the mechanical position sensor fails are respectively obtained;the motor speed of the sampling period before the mechanical position sensor fails,andis a two-phase voltageAnd
calculating the satisfaction condition of the two-phase voltage value to obtain the motor rotor angle theta of the sampling period before the mechanical position sensor fails[0]And motor speed
Correcting the included angle theta of the phase axis of the motor a in the fault through the following formula[m]：
Wherein, TPIs a sampling period; m is 1,2,3 …, n-1, n, whereinωmaxIs the maximum angular velocity of the motor.
Further, converting the three-phase input current into three-phase voltage values, the converting the three-phase voltage values into two-phase voltage values includes:
the voltage loop equation of the three-phase winding of the permanent magnet synchronous motor stator can be expressed as
Wherein u isa、ubAnd ucRespectively the voltage of each phase of the motor; ra、RbAnd RcIs the phase resistance of the motor stator; l isa、LbAnd LcRespectively the winding self-inductance of the motor; mabAnd MbaThe phase windings of the motor a and the phase b are mutually inductive; macAnd McaThe phase a of the motor is mutually inducted by the phase c windings; mbcAnd McbWinding the phase b and the phase c of the motorGroup mutual inductance;
for a surface-mounted three-phase permanent magnet synchronous motor, a three-phase symmetrical winding space structure is generally adopted, and the inductance, the resistance and the current of the surface-mounted three-phase permanent magnet synchronous motor meet the following relations:
get LeIs L-M, available as
According to the principle that the amplitudes before and after conversion are equal, two-phase voltages are obtained in a sampling period before a fault occurs at a mechanical positionAndis shown as
Wherein the content of the first and second substances,andthe three-phase voltage values of a sampling period before the mechanical position sensor fails are respectively obtained.
Further, θ[m]The optimal motor rotor angle of (a) is expressed as:
θ[m]＝θopt＝θ+mΔθ，m＝1,2,3,…,n
s.t
wherein, thetaoptThe rotor angle of the motor is optimal; i.e. iq_optIs an optimum of iqThe current is applied.
Compared with the prior art, the invention has the beneficial effects that:
the invention prevents the motor from stopping due to the loss of mechanical position signals in the running process of the permanent magnet synchronous motor, and the running of crisis equipment is safe; the overcurrent problem in the switching process from the mechanical position sensor to the position-free sensor can be prevented. The motor operation reliability is improved, and the motor control method can be used for motor control of elevators, electric airplanes and the like with higher safety level requirements.
Drawings
FIG. 1 is a block diagram of a system architecture according to an embodiment of the present invention;
FIG. 2 is a transformed coordinate system;
FIG. 3 is a flowchart of a method according to an embodiment of the present invention (a) a general flowchart, and (b) a speed and position estimation module without a mechanical position sensor.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Under the normal working condition of the permanent magnet synchronous motor, a mechanical position sensor vector control strategy is adopted, the SVPWM technology is utilized to convert high-voltage direct current obtained by a rectifier or a power battery into three-phase alternating current required by the motor through a motor controller inverse transformation module, and the running state of the motor is changed by adjusting SVPWM signals in real timeα、uβ、iαAnd iβValue, position and speed information of the motor obtained by the speed and position estimation moduleUnder the normal working condition, the 2 states of the two switches shown in the figure 1 adopt the vector control of the position sensor, when the mechanical position sensor fails and can not identify the correct motor position and rotating speed information, the system automatically switches to the 1 state, and uploads the motor position and rotating speed loss information to a user, so that the user can judge whether the system needs to quit the operation or not.
Referring to fig. 1, the system provided by the present invention includes:
a speed and position monitoring module for obtaining the included angle theta of the phase axis of the motor a and the angular speed omega of the motorr；
A speed and position estimation module for estimating the angular speed omega of the motor and the included angle theta of the phase axis of the motor a when the speed and position monitoring module can not detectr(ii) a Obtaining the included angle theta of the phase axis of the motor a and the angular velocity omega of the motorrAn estimate of (d);
the signal processing and generating unit is used for generating a control signal according to the detection value of the speed and position monitoring module or the estimation value of the speed and position estimation module;
and the switching unit is used for switching the speed and position monitoring module into a speed and position estimation module to be connected with the signal acquisition and generation unit when the speed and position monitoring module is detected to be incapable of detecting the position and rotating speed information of the motor.
The signal processing and generating unit includes:
the current acquisition module is used for acquiring three-phase input current of the motor;
the Clarke conversion module is used for converting the three-phase input current of the current acquisition module into two-phase quadrature axis current;
the Park conversion module is used for converting the two-phase quadrature axis current into a direct axis current under a two-phase rotating coordinate system according to the detection value of the speed and position monitoring module or the estimation value of the speed and position estimation module;
the speed conversion module is used for obtaining a given current of a q axis according to the rotating speed of a given motor and the detection value of the speed and position monitoring module or the motor angular speed in the estimation value of the speed and position estimation module;
the current conversion module is used for obtaining direct-axis voltage and quadrature-axis voltage of the motor according to the direct-axis current output by the Park conversion module under the two-phase rotating coordinate system, the given current of the speed conversion module and the conversion current;
the Park inverse transformation module is used for converting direct-axis voltage and quadrature-axis voltage of the motor into quadrature-axis voltage;
and the SVPWM signal generator acquires an SVPWM signal required by the motor controller according to the quadrature axis voltage and the switching sequence comparison table, triggers an IGBT in the inverse transformation module of the motor controller, and the inverse transformation module outputs three-phase alternating current required by the permanent magnet synchronous motor according to the trigger signal.
When the permanent magnet synchronous motor has a mechanical position sensor, the specific implementation steps are as follows, see fig. 3 (a):
(1) firstly, monitoring three-phase input current i of a motor in real time through a current acquisition modulea，ibAnd icThe method comprises the steps of converting three-phase alternating current into two-phase alternating current by coordinate transformation based on the principle of armature magnetomotive force balance of the permanent magnet synchronous motor, selecting an alpha axis to coincide with an a axis, and leading a beta axis to be 90 degrees ahead of the alpha axis as shown in figure 2, and supposing thatAndmagnetomotive forces in the a, b and c axis windings, respectively, assumingAndthe magnetomotive force in the alpha and beta axis windings respectively ensures that the amplitudes of the currents before and after conversion are equal, and converts the three-phase current of the motor into two-phase current.
The magnetomotive force balance equation can be expressed as
Wherein N is2Equivalent number of turns of two-phase windings alpha and beta, N3The number of turns of the three-phase windings a, b and c of the motor. The current amplitudes before and after conversion are kept equal, which can be obtained from the formula (1)
(2) The included angle theta between the rotor magnetic pole and the phase axis of the motor a can be obtained through a mechanical position sensor (a speed and position monitoring module) arranged at the end part of the motor, so that the static quadrature axis current i can be converted into the motor speed and the motor speedαAnd iβConverted into a direct-axis current i under a two-phase rotating coordinate systemdAnd iq。
(3) Given motor speed omegaRefAnd motor feedback rotation speed omegar(theta is calculated to obtain the feedback rotating speed omega of the motor by the derivative of timerOutput of speed and position monitoring module) is converted into a given current i of a q axis by a speed conversion moduleq_RefFeedback current id、iqAnd converting the currentThe direct-axis voltage and the quadrature-axis voltage of the motor obtained by the current conversion module are respectively udAnd uq。
Wherein R issIs the stator resistance of the motor; l isdAnd LqD-axis and q-axis inductances of the motor respectively; ΨfIs the permanent magnet flux linkage of the motor.
In which the current is convertedCan be expressed as
Permanent magnet flux linkage ΨfCan be expressed as
Wherein E isabThe effective value of the electromotive force of the motor wire; p is the number of pole pairs of the motor; and n is the rotating speed of the motor.
Angular velocity omega of motorrCan be expressed as a function of the motor speed n
(4) Direct-axis voltage u of a known electric machined、uqAnd obtaining quadrature axis voltage u via a Park inverse transformation moduleαAnd uβ
Since the motor belongs to an inductive load, the current lags behind the voltage, so udAnd uαAngle of (2)Can be expressed as
Wherein k issThe value is an angle modulation coefficient, is related to the SVPWM signal period and the motor phase inductance, and can be approximately constant.
(5) According to the volt-second equilibrium principle, the voltage within the sampling period T can be decomposed into:
in the formula, Tx，TyAnd T0Respectively non-zero voltage vector Ux，UyAnd zero voltage vector U0The duration of action within a cycle; u shaperefIs a desired voltage vector having a value of uαAnd uβCan be expressed as
(6) According to a non-zero voltage vector Ux，UyAnd zero voltage vector U0Combining with a five-segment or seven-segment SVPWM switching sequence comparison table, Table 1 shows UrefAnd the switching sequence comparison table in the I-th area can obtain the SVPWM signals required by the motor controller through the switching sequence table, trigger the IGBT in the inverse transformation module of the motor controller, and the inverse transformation module outputs the three-phase alternating current required by the permanent magnet synchronous motor according to the trigger signals.
TABLE 1SVPWM switching sequence table
Zone I UrefComparison table of switch switching sequence of position (seven-segment type SVPWM)
Zone I UrefComparison table of switch switching sequence of position (five-segment type SVPWM)
When a mechanical position sensor arranged at the end part of the motor fails, the included angle theta of the phase axis of the motor a and the angular speed omega of the motor cannot be obtained through the position sensorrThe vector control of the permanent magnet synchronous motor is switched to the position sensorless operation mode, i.e., from the operation mode 2 to the operation mode 1, as shown in fig. 3(a) and 3(b), andand reporting fault information. How to obtain the included angle theta and the motor angular velocity omegarThe method is the key of the position sensorless vector control of the permanent magnet synchronous motor, and the specific implementation steps of the speed and position estimation module are as follows. When the speed and position monitoring module has a fault, the speed and position estimation module obtains an angle theta and a motor angular speed omegar：
According to the three-phase input current i of the motor obtained by the current acquisition modulea、ibAnd icIn combination with the working principle of the permanent magnet synchronous motor, the voltage loop equation of the three-phase winding of the stator of the permanent magnet synchronous motor can be expressed as
Wherein u isa、ubAnd ucRespectively the voltage of each phase of the motor; ra、RbAnd RcIs the phase resistance of the motor stator; l isa、LbAnd LcRespectively the winding self-inductance of the motor; mabAnd MbaThe phase windings of the motor a and the phase b are mutually inductive; macAnd McaThe phase a of the motor is mutually inducted by the phase c windings; mbcAnd McbThe phase b of the motor and the phase c of the motor are mutually inducted by the winding.
The surface-mounted three-phase permanent magnet synchronous motor generally adopts a three-phase symmetrical winding space structure, and the inductance, the resistance and the current of the surface-mounted three-phase permanent magnet synchronous motor meet the following relationship
Get LeIs L-M, obtainable from formula (12) and formula (13)
According to the principle that the amplitudes before and after conversion are equal, two-phase voltages are obtained in a sampling period before a fault occurs at a mechanical positionAndcan be expressed as
Wherein the content of the first and second substances,andthe three-phase voltage values of a sampling period before the mechanical position sensor fails are respectively obtained.
From the expressions (2) to (9), the expression (14) and the expression (15), the voltage loop equation of the permanent magnet synchronous motor stator under the alpha and beta two-phase coordinate system can be expressed as
Wherein the content of the first and second substances,andcurrent values of a sampling period before the mechanical position sensor fails are respectively obtained; omegar0The motor speed of a sampling period before the mechanical position sensor fails.
The motor rotor angle theta of a sampling period before the mechanical position sensor fails can be obtained by the formula (16)[0]And motor speed
According to the formula (2), the current of the mechanical position sensor in the fault can be calculatedAndin order to accurately obtain the included angle theta in fault[m]And angular velocity of the motorθ[m]The following equation is satisfied:
wherein, TPIs a sampling period; m is 1,2,3 …, n-1, n, whereinωmaxIs the maximum angular velocity of the motor.
I can be calculated from the equations (2) and (3)dAnd iqCurrent value of when iqTheta at minimum value of current[m]For optimum motor rotor angle, theta at that time[m]Can be expressed as:
wherein, thetaoptThe rotor angle of the motor is optimal; i.e. iq_optIs an optimum of iqThe current is applied.
Based on estimated optimum motor rotor angle and estimatedThe SVPWM signal required by the motor controller is obtained by the flow shown in fig. 3 (a).
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.