Background
Parameter identification is an important means for acquiring parameters of a permanent magnet synchronous generator, and due to the continuous development of motor control theory and control technology and the urgent requirement of high-precision motor control technology, researchers pay more attention to the aspect of acquiring high-precision motor parameters in real time to improve the control performance of the permanent magnet synchronous motor. If the designed controller parameters are not properly matched with the controlled motor parameters, the control performance of the whole system is affected.
Through a large number of searches, some typical prior arts are found, for example, chinese invention patent with patent application number 201710538011.9 proposes a permanent magnet synchronous motor parameter identification system based on improved least square method, which identifies the real-time resistance value, real-time inductance value, and real-time permanent magnet flux linkage value of the permanent magnet synchronous motor by using a parameter identification algorithm based on improved least square method through a permanent magnet synchronous motor parameter acquisition system and a control system, the identification system includes a permanent magnet synchronous motor parameter acquisition system, a permanent magnet synchronous motor control system, and a parameter identification algorithm, wherein: the permanent magnet synchronous motor parameter acquisition system comprises a voltage acquisition device, a current acquisition device and a rotating speed acquisition device which are connected with the permanent magnet synchronous motor to be detected through a data transmission line; the permanent magnet synchronous motor control system adopts a sine wave vector control system with a direct axis current id equal to 0; the parameter identification algorithm adopts a permanent magnet synchronous motor parameter identification method based on an improved least square method. The invention can improve the efficiency of identifying the parameters of the permanent magnet synchronous motor, accelerate the identification speed and ensure the accuracy of identifying the parameters.
If the Chinese patent with the patent application number of 201910309508.2 provides a multi-parameter automatic identification method for a permanent magnet synchronous motor, basic parameters of the permanent magnet synchronous motor are input to a motor driver of the permanent magnet synchronous motor through an upper computer, then the upper computer controls the motor driver to operate in an open loop control mode, meanwhile, the permanent magnet synchronous motor is in a no-load condition, the upper computer controls the motor driver to sequentially identify the quadrature axis inductance, the direct axis inductance, the zero position of the motor, the stator resistance and the motor flux linkage of the permanent magnet synchronous motor for multiple times to obtain the total relative deviation difference of each parameter, and finally, whether the total relative deviation meets the convergence is judged, and if the total relative deviation meets the convergence, the automatic identification is completed; the method overcomes the problems of low efficiency and poor universality in the common design method, and has the characteristics of no need of using additional auxiliary tools, simplicity in operation, high identification precision and the like.
Also, for example, chinese patent application No. 201810170911.7 discloses a method, an apparatus, and a controller for identifying parameters of a permanent magnet synchronous motor, wherein the method for identifying parameters of a permanent magnet synchronous motor includes: acquiring a first parameter when a tested motor works at a preset current; determining a second parameter of the tested motor according to the first parameter; and calculating quadrature axis inductance, rotor permanent magnet flux linkage and direct axis inductance according to the first parameter and the second parameter. The invention can obtain the required parameters of the permanent magnet synchronous motor under various working conditions according to requirements, and has the advantages of simple realization and accurate test result.
It can be seen that how to identify the parameters of the permanent magnet synchronous motor, there are many practical problems to be dealt with in practical application, and no specific solutions are proposed
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a permanent magnet synchronous motor parameter identification method based on an LM algorithm, which has the following specific technical scheme:
a permanent magnet synchronous motor parameter identification method based on an LM algorithm comprises the following steps:
step 1, collecting q-axis voltage u of a permanent magnet synchronous motor by using an inverse M sequence as a system excitation signalqQ-axis current iqD axis current idAnd a rotational speed omegae;
Step 2, constructing a permanent magnet synchronous motor discrete equation, wherein the specific process is as follows:
2A, establishing a q-axis voltage equation of the permanent magnet synchronous motor
And 2B, discretizing a q-axis voltage equation of the permanent magnet synchronous motor by adopting a vector control method with id being 0 to obtain
And
after item shifting, the product is obtained
2C, order
Bonding of
To obtain
2D, order
Can obtain the product
Wherein R is
SIs the stator resistance, L
qIs an AC axial inductance,. psi
fIs a permanent magnet flux linkage, T is a discrete time, L
dIs a direct current shaft inductor;
and 3, solving the numerical values of a, b, c and d in the step 2 through an LM algorithm, wherein the specific process is as follows:
3A, selecting a fitting function, and enabling theta to be equal to (a b c d)
TI.e. by
Selecting an initial point theta
0And setting the damping factor to λ
00.01, where K is the number of iterations, K
maxThe maximum iteration number is n, and the number of the acquired numerical values is n;
3B, calculating
Calculating a function
Of the jacobian matrix
3C, calculating gk=(JTJ+λkI)-1JT(y-Aθk),θk+1=θk+gk;
3D, if
Let lambda
k+1=λ
k/10, return to step 3B, if
Let λ be
k+1=10·λ
kReturning to the step 3C;
step 4, substituting the numerical values of a, b, c and d obtained in the step 3 into a formula
Obtaining stator resistance R of the permanent magnet synchronous motor
SAC shaft inductor L
qAnd permanent magnet flux linkage psi
fThe value of (c).
Optionally, in step 1, the q-axis voltage u of the permanent magnet synchronous motor is acquired by using the inverse M sequence as a system excitation signalqQ-axis current iqD axis current idAnd a rotational speed omegaeThe specific method comprises the following steps:
1A, setting the q-axis voltage of a permanent magnet synchronous motor as a constant, superposing an inverse M sequence to the q-axis voltage of the permanent magnet synchronous motor running in a stable normal state, and carrying out primary sampling on the q-axis voltage, the q-axis current, the d-axis current and the rotating speed of the permanent magnet synchronous motor;
1B, keeping the q-axis voltage of the permanent magnet synchronous motor unchanged, and carrying out secondary sampling on the q-axis voltage, the q-axis current, the d-axis current and the rotating speed of the permanent magnet synchronous motor on the basis that the permanent magnet synchronous motor is not superposed with an inverse M sequence;
1C, obtaining the q-axis voltage u of the permanent magnet synchronous motor when the inverse M sequence is used as a system excitation signal by using the q-axis voltage, the q-axis current, the d-axis current and the rotating speed of the permanent magnet synchronous motor obtained in the step 1 and the q-axis voltage, the q-axis current, the d-axis current and the rotating speed of the permanent magnet synchronous motor obtained in the step 2qQ-axis current iqD axis current idAnd a rotational speed omegae。
The beneficial effects obtained by the invention comprise:
1. the inverse M sequence is selected as an input signal for identifying the parameters of the permanent magnet synchronous motor, so that the permanent magnet synchronous motor can be continuously excited, the parameters can be conveniently adjusted, and the accuracy of identifying the parameters of the permanent magnet synchronous motor is improved;
2. the invention discloses a method for identifying parameters of a permanent magnet synchronous motor based on an LM algorithm, which is a novel method for identifying the parameters of the permanent magnet synchronous motor, identifies the parameters of the permanent magnet synchronous motor, does not need to set part of motor parameters as fixed values, does not need to utilize an additional measuring instrument, and has the characteristics of low cost and applicability
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 below with reference to embodiments thereof; it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Other systems, methods, and/or features of the present embodiments will become apparent to those skilled in the art upon review of the following detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. Additional features of the disclosed embodiments are described in, and will be apparent from, the detailed description that follows.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. based on the orientation or positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, but it is not intended to indicate or imply that the device or component referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and are not to be construed as limiting the present patent, and the specific meaning of the terms described above will be understood by those of ordinary skill in the art according to the specific circumstances.
The invention relates to a permanent magnet synchronous motor parameter identification method based on an LM algorithm, which explains the following embodiments according to the descriptions shown in figures 1-2:
the first embodiment is as follows:
as shown in fig. 1 and 2, a method for identifying parameters of a permanent magnet synchronous motor based on an LM algorithm includes the following steps:
step 1, collecting q-axis voltage u of a permanent magnet synchronous motor by using an inverse M sequence as a system excitation signalqQ-axis current iqD axis current idAnd a rotational speed omegae;
Step 2, constructing a permanent magnet synchronous motor discrete equation, wherein the specific process is as follows:
2A, establishing a q-axis voltage equation of the permanent magnet synchronous motor
And 2B, discretizing a q-axis voltage equation of the permanent magnet synchronous motor by adopting a vector control method with id being 0 to obtain
And
after item shifting, the product is obtained
2C, order
Bonding of
To obtain
2D, order
Can obtain the product
Wherein R is
SIs the stator resistance, L
qIs an AC axial inductance,. psi
fIs a permanent magnet flux linkage, T is a discrete time, L
dIs a direct current shaft inductor;
and 3, solving the numerical values of a, b, c and d in the step 2 through an LM algorithm, wherein the specific process is as follows:
3A, selecting a fitting function, and enabling theta to be equal to (a b c d)
TI.e. by
Selecting an initial point theta
0And setting the damping factor to λ
00.01, where K is the number of iterations, K
maxThe maximum iteration number is n, and the number of the acquired numerical values is n;
3B, calculating
Calculating a function
Of the jacobian matrix
3C, calculating gk ═ JTJ+λkI)-1JT(y-Aθk),θk+1=θk+gk;
3D, if
Let lambda
k+1=λ
k/10, return to step 3B, if
Let λ be
k+1=10·λ
kReturning to the step 3C;
step 4, substituting the numerical values of a, b, c and d obtained in the step 3 into a formula
Obtaining stator resistance R of the permanent magnet synchronous motor
SAC shaft inductor L
qAnd permanent magnet flux linkage psi
fThe value of (c).
Compared with the M sequence, the inverse M sequence has greatly reduced direct current components, is a more ideal pseudo-random code sequence than the M sequence, can continuously excite an identification object, is convenient to adjust, and is an ideal excitation signal in system identification.
In the embodiment, the inverse M sequence is selected as the input signal for parameter identification of the permanent magnet synchronous motor, so that the permanent magnet synchronous motor can be continuously excited, the parameter can be conveniently adjusted, and the accuracy of parameter identification of the permanent magnet synchronous motor is improved.
In addition, at present, partial motor parameters are set as fixed values at home and abroad, and then the motor parameters are identified, or the motor parameters are identified by using an additional measuring instrument.
The LM algorithm can solve the least square problem of the nonlinear equation, and the method is a new method for identifying the parameters of the permanent magnet synchronous motor based on the LM algorithm to identify the parameters of the permanent magnet synchronous motor. Because partial motor parameters do not need to be set as fixed values and an additional measuring instrument does not need to be utilized, the method has low cost and strong applicability.
Example two:
as shown in fig. 1 and 2, a method for identifying parameters of a permanent magnet synchronous motor based on an LM algorithm includes the following steps:
step 1, collecting q-axis voltage u of a permanent magnet synchronous motor by using an inverse M sequence as a system excitation signalqQ-axis current iqD axis current idAnd a rotational speed omegae;
Step 2, constructing a permanent magnet synchronous motor discrete equation, wherein the specific process is as follows:
2A, establishing a q-axis voltage equation of the permanent magnet synchronous motor
And 2B, discretizing a q-axis voltage equation of the permanent magnet synchronous motor by adopting a vector control method with id being 0 to obtain
And
after item shifting, the product is obtained
2C, order
Bonding of
To obtain
2D, order
Can obtain the product
Wherein R is
SIs the stator resistance, L
qIs an AC axial inductance,. psi
fIs a permanent magnet flux linkage, T is a discrete time, L
dIs a direct current shaft inductor;
and 3, solving the numerical values of a, b, c and d in the step 2 through an LM algorithm, wherein the specific process is as follows:
3A, selecting a fitting function, and enabling theta to be equal to (a b c d)
TI.e. by
Selecting an initial point theta
0And setting the damping factor to λ
00.01, where K is the number of iterations, K
maxIs at mostIteration times, wherein n is the number of acquired numerical values;
3B, calculating
Calculating a function
Of the jacobian matrix
3C, calculating gk ═ JTJ+λkI)-1JT(y-Aθk),θk+1=θk+gk;
3D, if
Let lambda
k+1=λ
k/10, return to step 3B, if
Let λ be
k+1=10·λ
kReturning to the step 3C;
step 4, substituting the numerical values of a, b, c and d obtained in the step 3 into a formula
Obtaining stator resistance R of the permanent magnet synchronous motor
SAC shaft inductor L
qAnd permanent magnet flux linkage psi
fThe value of (c).
In step 1, the q-axis voltage u of the permanent magnet synchronous motor is acquired by using an inverse M sequence as a system excitation signalqQ-axis current iqD axis current idAnd a rotational speed omegaeThe specific method comprises the following steps:
the method comprises the following steps of 1A, setting the q-axis voltage of the permanent magnet synchronous motor as a constant, superposing an inverse M sequence to the q-axis voltage of the permanent magnet synchronous motor running in a stable normal state, and carrying out primary sampling on the q-axis voltage, the q-axis current, the d-axis current and the rotating speed of the permanent magnet synchronous motor. At this time, the sampled values of the q-axis voltage, the q-axis current, the d-axis current and the rotating speed of the permanent magnet synchronous motor are composed of two parts, one part is generated by the q-axis direct-current voltage, and the other part is generated by the inverse M sequence.
And 1B, keeping the q-axis voltage of the permanent magnet synchronous motor unchanged, and carrying out secondary sampling on the q-axis voltage, the q-axis current, the d-axis current and the rotating speed of the permanent magnet synchronous motor on the basis that the permanent magnet synchronous motor is not superposed with an inverse M sequence. The sampled value at this time is generated only by the q-axis dc voltage.
1C, obtaining the q-axis voltage u of the permanent magnet synchronous motor when the inverse M sequence is used as a system excitation signal by using the q-axis voltage, the q-axis current, the d-axis current and the rotating speed of the permanent magnet synchronous motor obtained in the step 1 and the q-axis voltage, the q-axis current, the d-axis current and the rotating speed of the permanent magnet synchronous motor obtained in the step 2qQ-axis current iqD axis current idAnd a rotational speed omegae。
In summary, the method for identifying parameters of a permanent magnet synchronous motor based on the LM algorithm disclosed by the present invention has the following beneficial technical effects:
1. the inverse M sequence is selected as an input signal for identifying the parameters of the permanent magnet synchronous motor, so that the permanent magnet synchronous motor can be continuously excited, the parameters can be conveniently adjusted, and the accuracy of identifying the parameters of the permanent magnet synchronous motor is improved;
2. the invention discloses a method for identifying parameters of a permanent magnet synchronous motor based on an LM algorithm, which is a novel method for identifying the parameters of the permanent magnet synchronous motor, identifies the parameters of the permanent magnet synchronous motor, does not need to set part of motor parameters as fixed values, does not need to utilize an additional measuring instrument, and has the characteristics of low cost and applicability
Although the invention has been described above with reference to various embodiments, it should be understood that many changes and modifications may be made without departing from the scope of the invention. That is, the methods, systems, and devices discussed above are examples, and various configurations may omit, replace, or add various processes or components as appropriate. For example, in alternative configurations, the methods may be performed in an order different than that described and/or various components may be added, omitted, and/or combined. Moreover, features described with respect to certain configurations may be combined in various other configurations, as different aspects and elements of the configurations may be combined in a similar manner. Further, elements therein may be updated as technology evolves, i.e., many of the elements are examples and do not limit the scope of the disclosure or claims.
Specific details are given in the description to provide a thorough understanding of the exemplary configurations including implementations. However, configurations may be practiced without these specific details, such as well-known circuits, processes, algorithms, structures, and techniques, which have been shown without unnecessary detail in order to avoid obscuring the configurations. This description provides example configurations only, and does not limit the scope, applicability, or configuration of the claims. Rather, the foregoing description of the configurations will provide those skilled in the art with an enabling description for implementing the described techniques. Various changes may be made in the function and arrangement of elements without departing from the spirit or scope of the disclosure.
It is intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention. The above examples are to be construed as merely illustrative and not limitative of the remainder of the disclosure. After reading the description of the invention, the skilled person can make various changes or modifications to the invention, and these equivalent changes and modifications also fall into the scope of the invention defined by the claims.