CN112003537B - Direct torque control method and device for alternating current motor and related components - Google Patents
Direct torque control method and device for alternating current motor and related components Download PDFInfo
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- CN112003537B CN112003537B CN202010868483.2A CN202010868483A CN112003537B CN 112003537 B CN112003537 B CN 112003537B CN 202010868483 A CN202010868483 A CN 202010868483A CN 112003537 B CN112003537 B CN 112003537B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/30—Direct torque control [DTC] or field acceleration method [FAM]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/02—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using supply voltage with constant frequency and variable amplitude
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Abstract
The application discloses a direct torque control method of an alternating current motor, which comprises the following steps: acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track; when the actual position is a preset position on any edge of the stator flux linkage track, outputting a pulse signal corresponding to a zero vector to control the inverter to work and acquiring the feedback torque of the alternating current motor; judging whether the feedback torque meets a preset condition or not; if yes, determining the current effective voltage vector according to the actual position, and outputting a pulse signal corresponding to the current effective voltage vector to control the inverter to work. This application can satisfy output voltage three-phase symmetry, half-wave symmetry and quarter symmetry requirement, reduces the output voltage harmonic, can realize direct torque control according to fixed switching frequency simultaneously, optimizes pulse output, and the range of application is wide. The application also discloses an alternating current motor direct torque control device, electronic equipment and a computer readable storage medium, which have the beneficial effects.
Description
Technical Field
The present disclosure relates to ac motor control, and more particularly, to a method and apparatus for controlling direct torque of an ac motor, and related components.
Background
In the field of alternating current transmission, the current control method has vector control and direct torque control, the vector control adopts the decoupling control idea to convert three-phase current of a motor into direct current under a synchronous rotating coordinate system for closed-loop control, the vector control is a continuous control system, and the dynamic and static performances are better under medium and high switching frequencies, but the dynamic performance is not good under low switching frequency.
The direct torque control abandons the decoupling control idea, uses the instantaneous voltage vector theory, directly carries out hysteresis comparison control of an upper boundary and a lower boundary under a stator coordinate system, controls the torque and the flux linkage within a certain tolerance range, has quick response of the torque of a control system and no overshoot, and is an alternating current speed regulation method with high dynamic and static performances. Traditional direct torque control can be with stator flux linkage operation at fixed polygon flux linkage orbit, for example eighteen-sided polygon and hexagon flux linkage orbit, and the hysteresis loop of upper and lower bound is adopted to the torque this moment and is compared, with torque control in certain tolerance scope, and tolerance scope size is adjusted by switching frequency regulator. However, the scheme has the problems of unfixed switching frequency and larger current harmonic content, and limits the application range to a certain extent.
Therefore, how to provide a solution to the above technical problem is a problem that needs to be solved by those skilled in the art.
Disclosure of Invention
The application aims to provide a direct torque control method, a direct torque control device, electronic equipment and a computer readable storage medium for an alternating current motor, which can meet the requirements of three-phase symmetry, half-wave symmetry and quarter-wave symmetry of output voltage, reduce harmonic waves of the output voltage, realize direct torque control according to fixed switching frequency, optimize pulse output and have wide application range.
In order to solve the above technical problem, the present application provides a direct torque control method for an ac motor, including:
acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track;
when the actual position is a preset position on any edge of the stator flux linkage track, outputting a pulse signal corresponding to a zero vector to control an inverter to work and obtain a feedback torque of the alternating current motor, wherein the preset positions on all edges of the stator flux linkage track are the same;
judging whether the feedback torque meets a preset condition or not;
if yes, determining a current effective voltage vector according to the actual position, and outputting a pulse signal corresponding to the current effective voltage vector to control the inverter to work.
Preferably, the process of acquiring the actual position of the stator flux linkage of the alternating current motor running on the stator flux linkage track specifically includes:
acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track through a motor model observer;
correspondingly, the process of acquiring the feedback torque of the alternating current motor specifically includes:
and acquiring the feedback torque of the alternating current motor through the motor model observer.
Preferably, the preset position is a midpoint position of each edge of the stator flux linkage track.
Preferably, the preset positions are positions symmetrical about a midpoint of each side of the stator flux linkage track.
Preferably, the direct torque control method of the ac motor further includes:
and when the pulse signal corresponding to the current effective voltage vector is output to control the inverter to work, the operation of judging whether the feedback torque meets the preset condition is not executed.
Preferably, the direct torque control method of the ac motor further includes:
judging whether the rotation direction of the alternating current motor is positive rotation or negative rotation;
and determining the preset condition according to the rotation direction.
Preferably, the preset conditions include:
when the rotation direction of the alternating current motor is positive rotation, the feedback moment is smaller than the lower boundary of the given hysteresis loop.
Preferably, the preset conditions include:
when the rotation direction of the alternating current motor is reverse, the feedback moment is larger than the upper boundary of the given hysteresis loop.
Preferably, the direct torque control method of the ac motor further includes:
calculating a target value according to the highest torque point and the lowest torque point of the alternating current motor, wherein the target value is half of the difference value of the highest torque point and the lowest torque point;
and obtaining the lower boundary of the given hysteresis loop by subtracting the given torque from the target value.
In order to solve the above technical problem, the present application further provides an ac motor direct torque control apparatus, including:
the acquisition module is used for acquiring the actual position of the stator flux linkage of the alternating current motor running on the stator flux linkage track;
the first processing module is used for outputting a pulse signal corresponding to a zero vector to control the inverter to work and acquiring the feedback torque of the alternating current motor when the actual position is a preset position on any edge of the stator flux linkage track, wherein the preset positions on all edges of the stator flux linkage track are the same;
the judging module is used for judging whether the feedback torque meets a preset condition or not, and if so, the second processing module is triggered;
and the second processing module is used for determining a current effective voltage vector according to the actual position and outputting a pulse signal corresponding to the current effective voltage vector to control the inverter to work.
Preferably, the obtaining module is specifically configured to:
acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track through a motor model observer;
correspondingly, the process of acquiring the feedback torque of the alternating current motor specifically includes:
and acquiring the feedback torque of the alternating current motor through the motor model observer.
Preferably, the preset position is a midpoint position of each edge of the stator flux linkage track.
Preferably, the preset position is a position symmetrical to each edge of the stator flux linkage track about a midpoint.
Preferably, the determining module is further configured to, when a pulse signal corresponding to the current effective voltage vector is output to control the inverter to work, not perform the operation of determining whether the feedback torque meets a preset condition.
Preferably, the direct torque control device for an ac motor further includes:
and the preprocessing module is used for judging whether the rotation direction of the alternating current motor is positive rotation or negative rotation and determining a preset condition according to the rotation direction.
Preferably, the preset conditions include:
when the rotation direction of the alternating current motor is positive rotation, the feedback moment is smaller than the lower boundary of the given hysteresis loop.
Preferably, the preset conditions include:
when the rotation direction of the alternating current motor is reverse, the feedback moment is larger than the upper boundary of the given hysteresis loop.
Preferably, the direct torque control device for an ac motor further includes:
and the calculation module is used for calculating a target value according to the highest torque point and the lowest torque point of the alternating current motor, wherein the target value is half of the difference value between the highest torque point and the lowest torque point, and a given torque and the target value are differed to obtain a given hysteresis lower boundary.
In order to solve the above technical problem, the present application further provides an electronic device, including:
a memory for storing a computer program;
a processor for implementing the steps of the ac motor direct torque control method as claimed in any one of the above when executing said computer program.
To solve the above technical problem, the present application further provides a computer-readable storage medium having a computer program stored thereon, where the computer program is executed by a processor to implement the steps of the direct torque control method of the ac motor according to any one of the above.
The application provides a direct torque control method of an alternating current motor, a zero vector is inserted into a preset position of each edge of a stator flux linkage track, the preset positions on each edge are the same, when direct torque control is carried out, a single-edge comparison scheme for comparing a fixed hysteresis loop single edge with a feedback torque is selected, corresponding pulse signals are selected to be output to control an inverter to work, the requirements of output voltage three-phase symmetry, half-wave symmetry and quarter-wave symmetry are met, output voltage harmonic waves are reduced, meanwhile, direct torque control can be achieved according to a fixed switching frequency, pulse output is optimized, and the application range is wide. The application also provides an alternating current motor direct torque control device, electronic equipment and a computer readable storage medium, and the alternating current motor direct torque control device, the electronic equipment and the computer readable storage medium have the same beneficial effects as the alternating current motor direct torque control method.
Drawings
In order to more clearly illustrate the embodiments of the present application, the drawings needed for the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained by those skilled in the art without inventive effort.
Fig. 1 is a space vector diagram of a permanent magnet synchronous motor provided by the present application in a stator α β coordinate system and a dq coordinate system;
FIG. 2 is a schematic diagram of a voltage vector and stator flux linkage path provided herein;
FIG. 3 is a flow chart illustrating steps of a method for direct torque control of an AC motor according to the present application;
fig. 4 is a schematic diagram of a synchronous three-frequency-division hexagonal stator flux linkage track according to an embodiment of the present application;
fig. 5 is a schematic diagram of a preset position according to an embodiment of the present disclosure;
fig. 6 is a schematic diagram of another preset position provided in the embodiment of the present application;
fig. 7 is a schematic diagram of another preset position provided in the embodiment of the present application;
FIG. 8 is a schematic diagram of a torque waveform and torque comparison provided by an embodiment of the present application;
fig. 9 is a schematic view of a direct torque control structure of a permanent magnet synchronous motor according to an embodiment of the present disclosure;
fig. 10 is a schematic structural diagram of an ac motor direct torque control apparatus provided in the present application;
fig. 11 is a schematic structural diagram of an electronic device provided in the present application.
Detailed Description
The core of the application is to provide a direct torque control method, a direct torque control device, electronic equipment and a computer readable storage medium for an alternating current motor, which can meet the requirements of three-phase symmetry, half-wave symmetry and quarter-wave symmetry of output voltage, reduce harmonic waves of the output voltage, realize direct torque control according to fixed switching frequency, optimize pulse output and have wide application range.
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In order to facilitate understanding of the method for controlling direct torque of an ac motor provided in the present application, a principle of direct torque control will be described below by taking a permanent magnet synchronous motor as an example, space vectors of the permanent magnet synchronous motor in a stator α β coordinate system and a stator dq coordinate system are shown in fig. 1, and an axis d is taken as an axis direction of a permanent magnet excitation magnetic field. The electromagnetic torque equation of the motor is as follows:
wherein, deltasIs stator flux linkage vector
And rotor flux linkage vector
The angle of included, commonly referred to as the torque angle, illustrates the change deltasCan change Te。
The control variable for direct torque control being the stator flux linkage vector
According to the motor model and stator flux linkage under the motor static coordinate system
And stator voltage vector
The relationship of (1) is:
description of the stator flux linkage
Voltage of stator
Control, by reasonable selection of the stationary vector, can be right
Is adjusted in amplitude and angle.
In steady state conditions, the stator flux linkage vector
And the rotor are all rotating at synchronous speed, load angle deltasIs constant. However, in transient conditions, if the stator flux linkage vector is made
Exceeds the rotor speed, the load angle deltasWill become larger if the stator flux linkage is maintained again
The amplitude is unchanged, the electromagnetic torque increases. On the contrary, if the stator flux linkage is maintained again
The amplitude is constant and the rotational speed is lower than the rotor speed, the load angle deltasIt is reduced and the electromagnetic torque is reduced.
In eight switching states of the inverter, as shown in fig. 2, selection of the appropriate switching voltage vector can control the stator flux linkage
And thus the torque. P when stator flux linkage is in flux linkage sector 11At this time, a boundary threshold value on the stator flux linkage amplitude is reached, and if the torque is to be increased, u can be selected2The stator flux linkage is rotated forward, increasing the load angle while decreasing the stator flux linkage amplitude. If the torque is to be reduced, u may be selected5The stator flux linkage is rotated backwards, increasing the load angle while decreasing the stator flux linkage amplitude, and if torque is to be maintained, the zero vector may be selected.
The following describes a method for controlling direct torque of an ac motor provided by the present application in detail.
Referring to fig. 3, fig. 3 is a flowchart illustrating steps of a direct torque control method for an ac motor according to the present application, where the direct torque control method for an ac motor includes:
s101: acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track;
specifically, the direct torque control may operate the stator flux linkage at a fixed polygonal flux linkage trajectory, such as an octagonal stator flux linkage trajectory, a hexagonal stator flux linkage trajectory, or the like. The present embodiment is described with respect to a synchronous three-frequency-division hexagonal stator flux linkage track, but the present invention is also applicable to other multilevel converters, polygonal stator flux linkage tracks, and multi-frequency-division.
Referring to fig. 4, fig. 4 is a schematic diagram of a synchronous three-frequency-division hexagonal stator flux linkage track provided by an embodiment of the present application, along which a stator flux linkage runs. It can be understood that when the stator flux linkage runs at different positions of the stator flux linkage track, the voltage vectors to be selected are different, the output pulse signals are different, and in order to optimize the pulse output, the embodiment first determines the actual position of the stator flux linkage running on the stator flux linkage track. Specifically, the actual position of the stator flux linkage of the alternating current motor running on the stator flux linkage track can be obtained according to the preset time period, the actual position of the stator flux linkage of the alternating current motor running on the stator flux linkage track can also be obtained after the obtaining instruction is received, and the embodiment is not limited to the triggering condition for obtaining the actual position.
S102: when the actual position is a preset position on any edge of the stator flux linkage track, outputting a pulse signal corresponding to a zero vector to control the inverter to work and acquiring the feedback torque of the alternating current motor, wherein the preset positions on all the edges of the stator flux linkage track are the same;
specifically, before executing the step, an operation of inserting a zero vector at a preset position on each side of the stator flux linkage track may be further included, so that when the stator flux linkage runs to the preset position, a pulse signal corresponding to the zero vector is output to control the inverter to operate, and direct torque control is realized. The preset positions on each side of the stator flux linkage track are the same so as to reduce the harmonic wave of the output voltage. As a preferred embodiment, referring to fig. 5, the preset position may be a midpoint position of each side, as another preferred embodiment, referring to fig. 6, the preset position may be a position symmetrical to the midpoint on each side of the stator flux linkage track, as another preferred embodiment, the preset position may also be a position symmetrical to a boundary of two adjacent sectors, referring to fig. 7, zero vectors inserted on the sector 1 and the sector 2 are symmetrical to a boundary of the sector 1 and the sector 2, and using the above-mentioned preset position to insert the zero vectors, three-phase symmetry, half-wave symmetry, and quarter-wave symmetry requirements of the output voltage may be met, and output voltage harmonics may be further reduced, and at this time, the waveform of the output voltage is as shown in fig. 8.
Specifically, when the stator flux linkage runs to a preset position on any edge of the stator flux linkage track, a zero vector is inserted into the preset position in advance, and therefore a pulse signal corresponding to the zero vector is output to control the inverter to work. And in the process of outputting the pulse signal corresponding to the zero vector, obtaining the feedback torque of the alternating current motor to carry out hysteresis comparison so as to control the torque within a certain tolerance range. In this embodiment, the feedback torque of the ac motor may be obtained according to a preset obtaining period, or the feedback torque of the ac motor may be obtained after receiving the obtaining instruction, and the embodiment is not specifically limited herein for the trigger condition of obtaining the feedback torque of the ac motor.
S103: judging whether the feedback torque meets a preset condition, if so, executing S104;
specifically, the objective of this step is to perform hysteresis comparison according to the feedback torque to determine whether the torque needs to be adjusted, and control the torque within a certain tolerance range. As a preferred embodiment, the present application adopts a hysteresis single boundary comparison scheme, and compares the feedback torque with a preset given hysteresis upper boundary or a preset given hysteresis lower boundary, and accordingly, the preset condition is that the feedback torque is smaller than the given hysteresis lower boundary or the feedback torque is larger than the given hysteresis upper boundary. It can be understood that different effective voltage vectors and zero vectors have different effects on the torque when the alternating current motor rotates forwards or reversely, the torque is reduced when the zero vector acts on the positive rotation of the alternating current motor, the effective voltage vector is selected to increase the torque when the torque is reduced to the lower boundary of a given hysteresis loop, the torque is increased when the zero vector acts on the negative rotation of the alternating current motor, and the effective vector is selected to decrease the torque when the torque is increased to the upper boundary of the given hysteresis loop. In order to improve the accuracy of the direct current torque control, as a preferred embodiment, the direct torque control method for the alternating current motor further includes determining whether the rotation direction of the alternating current motor is forward rotation or reverse rotation, and determining a preset condition according to the rotation direction. Specifically, when the alternating current motor rotates forwards, the lower boundary of the hysteresis loop is selected as a preset condition, and when the alternating current motor rotates backwards, the upper boundary of the hysteresis loop is selected as a preset condition. It is understood that when the ac motor rotates forward, the feedback torque greater than or equal to the given lower hysteresis boundary determines that the preset condition is not satisfied, and correspondingly, when the ac motor rotates backward, the feedback torque less than or equal to the given upper hysteresis boundary determines that the preset condition is not satisfied.
As a preferred embodiment, the given hysteresis lower boundary may be obtained by calculating a target value according to the highest torque point and the lowest torque point of the ac motor, where the target value is half of a difference value between the highest torque point and the lowest torque point, and subtracting the given torque from the target value to obtain the given hysteresis lower boundary.
S104: and determining a current effective voltage vector according to the actual position, and outputting a pulse signal corresponding to the current effective voltage vector to control the inverter to work.
Specifically, referring to FIGS. 5-7, the effective voltage vector u1To u6The stator flux linkage track is divided into 6 sectors, and when the stator flux linkage runs in different sectors, the selected current effective voltage vectors are different, so that the effective voltage vectors need to be selected according to the actual position of the stator flux linkage, and then pulse signals corresponding to the current effective voltage vectors are output to control the inverter to work.
Specifically, referring to fig. 5, taking the preset position as the midpoint position of each edge as an example, assuming that the current stator flux linkage runs in the first sector, if the ac motor rotates forward, a zero vector u is generated when the torque needs to be reduced0When the torque is reduced to the lower boundary of the given hysteresis loop, selecting a voltage vector u parallel to the edge where the actual position of the current stator flux linkage is located3The torque is increased as the current effective voltage vector, and the operation of determining whether the feedback torque satisfies the preset condition in S103 is not performed during the period of transmitting the effective voltage vector. It will be appreciated that during the active voltage vector period, the torque will increase, the stator flux linkage will run counter-clockwise,when it is operated to a preset position, it will output a zero vector u0Reducing the moment, repeating the steps S103-S104 in the process of generating the zero vector, and referring to FIG. 8, a schematic diagram of comparing the moment waveform with the moment is shown; if the AC motor rotates reversely and the required torque is increased, a zero vector u is generated0When the moment is increased to the upper boundary of the given hysteresis loop, selecting a voltage vector u parallel to the edge where the actual position of the current stator flux linkage is located6The torque is reduced as a current effective voltage vector. It can be understood that the scheme of the present application can realize fixed carrier ratio control, the carrier ratio is the current switching frequency divided by the current operating frequency, the operating frequency is fixed, and therefore, the switching frequency is fixed.
It should be noted that: the zero vector comprises u0And u7Here by u0General term, use u in detail0And u7The selection should be based on the principle of minimum switching times.
It can be seen that, in this embodiment, a zero vector is inserted into a preset position on each side of a stator flux linkage track, and the preset positions on each side are the same, when direct torque control is performed, a single-boundary comparison scheme for comparing a single boundary of a hysteresis loop with a feedback torque is selected to select and output a corresponding pulse signal to control the inverter to work, thereby satisfying requirements of three-phase symmetry, half-wave symmetry, and quarter-wave symmetry of output voltage, reducing harmonic waves of the output voltage, and simultaneously realizing direct torque control according to a fixed switching frequency, optimizing pulse output, and having a wide application range.
On the basis of the above-described embodiment:
as a preferred embodiment, the process of acquiring the actual position of the stator flux linkage running on the stator flux linkage track of the ac motor specifically includes:
acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track through a motor model observer;
correspondingly, the process of acquiring the feedback torque of the alternating current motor specifically comprises the following steps:
and acquiring the feedback torque of the alternating current motor through a motor model observer.
Specifically, referring to fig. 9, fig. 9 is a schematic diagram of a direct torque control structure of a permanent magnet synchronous motor provided by the present application, where a converter collects an intermediate voltage and two stator currents, and a stator flux linkage, an electromagnetic torque, and rotation speed information of an ac motor are observed by a motor model observer.
Referring to fig. 10, fig. 10 is a schematic structural diagram of an ac motor direct torque control device provided in the present application, where the ac motor direct torque control device includes:
the acquisition module 11 is used for acquiring the actual position of the stator flux linkage of the alternating current motor running on the stator flux linkage track;
the first processing module 12 is configured to output a pulse signal corresponding to a zero vector to control the inverter to operate and obtain a feedback torque of the ac motor when the actual position is a preset position on any edge of the stator flux linkage track, where the preset positions on each edge of the stator flux linkage track are the same;
the judging module 13 is configured to judge whether the feedback torque meets a preset condition, and if so, trigger the second processing module 14;
and the second processing module 14 is configured to determine a current effective voltage vector according to the actual position, and output a pulse signal corresponding to the current effective voltage vector to control the inverter to operate.
It can be seen that, in this embodiment, a zero vector is inserted into a preset position on each side of a stator flux linkage track, and the preset positions on each side are the same, when direct torque control is performed, a single-boundary comparison scheme for comparing a single boundary of a hysteresis loop with a feedback torque is selected to select and output a corresponding pulse signal to control the inverter to work, thereby satisfying requirements of three-phase symmetry, half-wave symmetry, and quarter-wave symmetry of output voltage, reducing harmonic waves of the output voltage, and simultaneously realizing direct torque control according to a fixed switching frequency, optimizing pulse output, and having a wide application range.
As a preferred embodiment, the obtaining module 11 is specifically configured to:
acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track through a motor model observer;
correspondingly, the process of acquiring the feedback torque of the alternating current motor specifically comprises the following steps:
and acquiring the feedback torque of the alternating current motor through a motor model observer.
As a preferred embodiment, the preset position is a midpoint position of each side of the stator flux linkage track.
As a preferred embodiment, the predetermined positions are positions on each side of the stator flux linkage track that are symmetrical about the midpoint.
As a preferred embodiment, the determining module 13 is further configured to, when outputting a pulse signal corresponding to the current effective voltage vector to control the inverter to operate, not perform an operation of determining whether the feedback torque satisfies the preset condition.
As a preferred embodiment, the direct torque control device for an alternating current motor further includes:
and the preprocessing module is used for judging whether the rotation direction of the alternating current motor is positive rotation or negative rotation and determining a preset condition according to the rotation direction.
As a preferred embodiment, the preset conditions include:
when the rotation direction of the alternating current motor is positive rotation, the feedback moment is smaller than the lower boundary of the given hysteresis loop.
As a preferred embodiment, the preset conditions include:
when the rotation direction of the alternating current motor is reverse, the feedback moment is larger than the upper boundary of the given hysteresis loop.
As a preferred embodiment, the direct torque control device for an alternating current motor further includes:
and the calculation module is used for calculating a target value according to the highest torque point and the lowest torque point of the alternating current motor, the target value is half of the difference value between the highest torque point and the lowest torque point, and the given torque and the target value are differed to obtain a given hysteresis lower boundary.
On the other hand, the present application further provides an electronic device, as shown in fig. 11, which shows a schematic structural diagram of an electronic device according to an embodiment of the present application, where the electronic device according to the embodiment may include: a processor 21 and a memory 22.
Optionally, the electronic device may further comprise a communication interface 23, an input unit 24 and a display 25 and a communication bus 26.
The processor 21, the memory 22, the communication interface 23, the input unit 24 and the display 25 are all communicated with each other through a communication bus 26.
In the embodiment of the present application, the processor 21 may be a Central Processing Unit (CPU), an application specific integrated circuit, a digital signal processor, an off-the-shelf programmable gate array or other programmable logic device, etc.
The processor may call a program stored in the memory 22. Specifically, the processor may perform operations performed on the electronic device side in the following embodiments of the ac motor direct torque control method.
The memory 22 is used for storing one or more programs, the program may include program codes, the program codes include computer operation instructions, and in the embodiment of the present application, the memory stores at least the program for realizing the following functions:
acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track;
when the actual position is a preset position on any edge of the stator flux linkage track, outputting a pulse signal corresponding to a zero vector to control an inverter to work and obtain a feedback torque of the alternating current motor, wherein the preset positions on all edges of the stator flux linkage track are the same;
judging whether the feedback torque meets a preset condition or not;
if yes, determining a current effective voltage vector according to the actual position, and outputting a pulse signal corresponding to the current effective voltage vector to control the inverter to work.
It can be seen that, in this embodiment, a zero vector is inserted into a preset position on each side of a stator flux linkage track, and the preset positions on each side are the same, when direct torque control is performed, a single-boundary comparison scheme for comparing a single boundary of a hysteresis loop with a feedback torque is selected to select and output a corresponding pulse signal to control the inverter to work, thereby satisfying requirements of three-phase symmetry, half-wave symmetry, and quarter-wave symmetry of output voltage, reducing harmonic waves of the output voltage, and simultaneously realizing direct torque control according to a fixed switching frequency, optimizing pulse output, and having a wide application range.
In one possible implementation, the memory 22 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application program required by at least one function (such as a given hysteresis lower boundary calculation function, etc.), and the like; the storage data area may store data created according to the use of the computer.
Further, the memory 22 may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device or other volatile solid state storage device.
The communication interface 23 may be an interface of a communication module, such as an interface of a GSM module.
The present application may also include a display 24 and an input unit 25, etc.
Of course, the structure of the internet of things device shown in fig. 11 does not constitute a limitation on the internet of things device in the embodiment of the present application, and in practical applications, the electronic device may include more or less components than those shown in fig. 11, or some components in combination.
In another aspect, the present application further provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the ac motor direct torque control method as described in any one of the above embodiments.
For the introduction of a computer-readable storage medium provided in the present application, please refer to the above embodiments, which are not described herein again.
The computer-readable storage medium provided by the application has the same beneficial effects as the direct torque control method of the alternating current motor.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (18)
1. A method of direct torque control of an ac motor, comprising:
acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track;
when the actual position is a preset position on any edge of the stator flux linkage track, outputting a pulse signal corresponding to a zero vector to control an inverter to work and obtain a feedback torque of the alternating current motor, wherein the preset positions on all edges of the stator flux linkage track are the same;
judging whether the feedback torque meets a preset condition or not;
if yes, determining a current effective voltage vector according to the actual position, and outputting a pulse signal corresponding to the current effective voltage vector to control the inverter to work;
the direct torque control method of the alternating current motor further comprises the following steps:
calculating a target value according to the highest torque point and the lowest torque point of the alternating current motor, wherein the target value is half of the difference value of the highest torque point and the lowest torque point;
and obtaining a given hysteresis lower boundary by subtracting the given torque from the target value.
2. The direct torque control method for the alternating current motor according to claim 1, wherein the process of acquiring the actual position of the stator flux linkage running on the stator flux linkage track of the alternating current motor specifically comprises:
acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track through a motor model observer;
correspondingly, the process of acquiring the feedback torque of the alternating current motor specifically includes:
and acquiring the feedback torque of the alternating current motor through the motor model observer.
3. The method of claim 1, wherein the predetermined position is a midpoint position of each side of the stator flux linkage path.
4. The method of claim 1, wherein the predetermined positions are positions on each side of the stator flux linkage path that are symmetrical about a midpoint.
5. The ac machine direct torque control method according to claim 1, further comprising:
and when the pulse signal corresponding to the current effective voltage vector is output to control the inverter to work, the operation of judging whether the feedback torque meets the preset condition is not executed.
6. The ac machine direct torque control method according to claim 1, further comprising:
judging whether the rotation direction of the alternating current motor is positive rotation or negative rotation;
and determining the preset condition according to the rotation direction.
7. The ac motor direct torque control method according to claim 6, wherein the preset conditions include:
when the rotation direction of the alternating current motor is positive rotation, the feedback moment is smaller than the lower boundary of the given hysteresis loop.
8. The ac motor direct torque control method according to claim 6, wherein the preset conditions include:
when the rotation direction of the alternating current motor is reverse, the feedback moment is larger than the upper boundary of the given hysteresis loop.
9. An alternating current motor direct torque control apparatus, comprising:
the acquisition module is used for acquiring the actual position of the stator flux linkage of the alternating current motor running on the stator flux linkage track;
the first processing module is used for outputting a pulse signal corresponding to a zero vector to control the inverter to work and acquiring the feedback torque of the alternating current motor when the actual position is a preset position on any edge of the stator flux linkage track, wherein the preset positions on all edges of the stator flux linkage track are the same;
the judging module is used for judging whether the feedback torque meets a preset condition or not, and if so, the second processing module is triggered;
the second processing module is used for determining a current effective voltage vector according to the actual position and outputting a pulse signal corresponding to the current effective voltage vector to control the inverter to work;
the direct torque control device of the alternating current motor further comprises:
and the calculation module is used for calculating a target value according to the highest torque point and the lowest torque point of the alternating current motor, wherein the target value is half of the difference value between the highest torque point and the lowest torque point, and a given torque and the target value are differed to obtain a given hysteresis lower boundary.
10. The ac machine direct torque control apparatus of claim 9, wherein the acquisition module is specifically configured to:
acquiring the actual position of the stator flux linkage of the alternating current motor running on a stator flux linkage track through a motor model observer;
correspondingly, the process of acquiring the feedback torque of the alternating current motor specifically includes:
and acquiring the feedback torque of the alternating current motor through the motor model observer.
11. The ac machine direct torque control device of claim 10, wherein the predetermined position is a midpoint position of each side of the stator flux linkage path.
12. The ac machine direct torque control device of claim 10, wherein the predetermined positions are symmetrical about a midpoint on each side of the stator flux linkage path.
13. The apparatus of claim 10, wherein the determining module is further configured to not perform the operation of determining whether the feedback torque satisfies a predetermined condition when outputting a pulse signal corresponding to a current effective voltage vector to control the inverter to operate.
14. The ac machine direct torque control device of claim 10, further comprising:
and the preprocessing module is used for judging whether the rotation direction of the alternating current motor is positive rotation or negative rotation and determining a preset condition according to the rotation direction.
15. The ac machine direct torque control device as claimed in claim 14, wherein the preset conditions include:
when the rotation direction of the alternating current motor is positive rotation, the feedback moment is smaller than the lower boundary of the given hysteresis loop.
16. The ac machine direct torque control device as claimed in claim 15, wherein the preset conditions include:
when the rotation direction of the alternating current motor is reverse, the feedback moment is larger than the upper boundary of the given hysteresis loop.
17. An electronic device, comprising:
a memory for storing a computer program;
a processor for implementing the steps of the ac machine direct torque control method according to any one of claims 1 to 8 when executing said computer program.
18. A computer-readable storage medium, characterized in that a computer program is stored thereon, which computer program, when being executed by a processor, carries out the steps of the method for direct torque control of an alternating current motor according to any one of claims 1-8.
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|---|---|---|---|---|
| CN103973192A (en) * | 2014-04-25 | 2014-08-06 | 中国矿业大学 | Method for optimizing DTC system of six-phase asynchronous motor |
| CN108667381A (en) * | 2018-04-24 | 2018-10-16 | 上海电力学院 | TLDMC-PMSM system control methods based on the stagnant ring of dynamic torque |
| CN109217765A (en) * | 2018-09-17 | 2019-01-15 | 沈阳工业大学 | A kind of double three-phase permanent-magnetic synchronous motor Direct Torque Control |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103973192A (en) * | 2014-04-25 | 2014-08-06 | 中国矿业大学 | Method for optimizing DTC system of six-phase asynchronous motor |
| CN108667381A (en) * | 2018-04-24 | 2018-10-16 | 上海电力学院 | TLDMC-PMSM system control methods based on the stagnant ring of dynamic torque |
| CN109217765A (en) * | 2018-09-17 | 2019-01-15 | 沈阳工业大学 | A kind of double three-phase permanent-magnetic synchronous motor Direct Torque Control |
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