Mechanical admittance testing method and device for motor stator system
1. A mechanical admittance testing method for a motor stator system is characterized by comprising the following steps:
s1, fixing the stator system on a motor workbench, selecting N excitation points on the stator tooth surface according to the circumferential direction, and selecting M target points on the shell according to the circumferential direction;
s2, arranging acceleration sensors at target points respectively;
s3, selecting any one excitation point j, and applying an excitation force P to the excitation pointj(omega) obtaining the acceleration R of each target point respectivelyi(ω)；
S4, finding the admittance H of the target point i relative to the excitation point jij(ω)：Hij(ω)＝Ri(ω)/Pj(ω)；
Where j is 1,2 … …, N, i is 1,2 … …, M, ω is the angular frequency.
2. The method as claimed in claim 1, wherein the excitation points are distributed uniformly along the circumferential direction on the stator tooth surface.
3. The method as claimed in claim 1, wherein the target point is uniformly distributed on the housing along a circumferential direction.
4. The method as claimed in claim 1, wherein the number N of excitation points is equal to the number M of target points.
5. The method for testing mechanical admittance of a motor stator system according to claim 4, wherein the excitation points and the target points are uniformly distributed along the circumferential direction and have one-to-one correspondence in position, and the pair of excitation points and the target points corresponding in position are located on the same radial straight line.
6. An electric machine stator system mechanical admittance testing arrangement, the arrangement comprising:
vibration exciter: the excitation mechanism is used for applying excitation force on the selected excitation points, and N excitation points are selected and distributed in the circumferential direction of the stator tooth surface;
an acceleration sensor: arranging the target points in the selected circumferential direction of the shell, and measuring the acceleration of the target points, wherein M target points are selected and distributed in the circumferential direction of the shell;
a processor: processing the exciting force and the acceleration to obtain the admittance H of the target point i relative to the exciting point jij(ω)：Hij(ω)＝Ri(ω)/Pj(ω)，Pj(ω) is the excitation force applied at the excitation point j, Ri(ω) is the acceleration of the target point i, j is 1,2 … …, N, i is 1,2 … …, M, ω is the angular frequency.
7. The mechanical admittance testing device of an electric machine stator system according to claim 6, wherein the excitation points are uniformly distributed on the stator tooth surface in a circumferential direction.
8. The mechanical admittance testing device of an electric machine stator system according to claim 6, wherein the target point housings are uniformly distributed in a circumferential direction.
9. The mechanical admittance testing device of an electric machine stator system according to claim 6, wherein the number of excitation points N is equal to the number of target points M.
10. The mechanical admittance testing device of a motor stator system according to claim 9, wherein the excitation points and the target points are uniformly distributed along a circumferential direction and have one-to-one correspondence in position, and the pair of excitation points and the target points corresponding in position are located on the same radial straight line.
Background
When vibration analysis is performed, it is far from sufficient to study the vibration characteristics of the motor only by the natural frequency. The vibration resistance of the motor structure can be measured by using a transfer function of the exciting force and the response. For this reason, the concept of electromechanical admittance matrices has been proposed. The smaller the mechanical admittance is, the smaller the vibration and noise amplitude generated by the response of the motor structure under the action of a certain dynamic excitation force is. At present, the mechanical admittance test of the motor stator system is relatively little researched, but the mechanical admittance matrix test of the motor stator system is crucial to the research of the vibration characteristic of the motor. In the path analysis technique, the transfer function of the mechanical system of the machine is described by means of an admittance matrix. The size of the mechanical admittance of the motor stator system intuitively reveals the vibration resistance of the motor mechanical system from the perspective of a transfer function theory. Therefore, how to accurately and reliably perform the mechanical admittance test of the electrode stator system becomes an urgent technical problem to be solved.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a mechanical admittance testing method for a stator system of a motor.
The purpose of the invention can be realized by the following technical scheme:
a mechanical admittance testing method for a motor stator system comprises the following steps:
s1, fixing the stator system on a motor workbench, selecting N excitation points on the stator tooth surface according to the circumferential direction, and selecting M target points on the shell according to the circumferential direction;
s2, arranging acceleration sensors at target points respectively;
s3, selecting any one excitation point j, and applying an excitation force P to the excitation pointj(omega) obtaining the acceleration R of each target point respectivelyi(ω)；
S4, finding the admittance H of the target point i relative to the excitation point jij(ω)：Hij(ω)＝Ri(ω)/Pj(ω)；
Where j is 1,2 … …, N, i is 1,2 … …, M, ω is the angular frequency.
Preferably, the excitation points are uniformly distributed on the stator tooth surface in the circumferential direction.
Preferably, the target point machine shell is uniformly distributed in the circumferential direction.
Preferably, the number N of excitation points is equal to the number M of target points.
Preferably, the excitation points and the target points are uniformly distributed along the circumferential direction and are in one-to-one correspondence in position, and the pair of excitation points and the target points which are in the corresponding position are located on the same radial straight line.
An electric machine stator system mechanical admittance testing arrangement, the arrangement comprising:
vibration exciter: the excitation mechanism is used for applying excitation force on the selected excitation points, and N excitation points are selected and distributed in the circumferential direction of the stator tooth surface;
an acceleration sensor: arranging the target points in the selected circumferential direction of the shell, and measuring the acceleration of the target points, wherein M target points are selected and distributed in the circumferential direction of the shell;
a processor: processing the exciting force and the acceleration to obtain the admittance H of the target point i relative to the exciting point jij(ω)：Hij(ω)＝Ri(ω)/Pj(ω)，Pj(ω) is the excitation force applied at the excitation point j, Ri(ω) is the acceleration of the target point i, j is 1,2 … …, N, i is 1,2 … …, M, ω is the angular frequency.
Preferably, the excitation points are uniformly distributed on the stator tooth surface in the circumferential direction.
Preferably, the target point machine shell is uniformly distributed in the circumferential direction.
Preferably, the number N of excitation points is equal to the number M of target points.
Preferably, the excitation points and the target points are uniformly distributed along the circumferential direction and are in one-to-one correspondence in position, and the pair of excitation points and the target points which are in the corresponding position are located on the same radial straight line.
Compared with the prior art, the invention has the following advantages:
(1) the method has important significance for the research of motor vibration analysis and motor mechanical characteristics, overcomes the defects in the motor admittance test at present, and provides a foundation for the vibration analysis of the motor and the research of the motor mechanical characteristics.
(2) The method can be widely applied to mechanical admittance measurement of various motor stator systems, the measured result has higher accuracy, the vibration analysis of the motor provides an important basis, and meanwhile, the testing method is utilized to provide powerful test reference for vibration contribution analysis of the motor mechanical system so as to reduce the vibration noise of the motor.
Drawings
FIG. 1 is a block flow diagram of a method for testing mechanical admittance of a stator system of an electric machine according to the present invention;
FIG. 2 is a schematic view of the present invention measuring mechanical admittance of a stator system by applying an excitation force at a single excitation point;
FIG. 3 is a schematic diagram of the transmission of the exciting force of the motor stator system;
FIG. 4 is a mechanical admittance spectrum of the stator system of a test prototype at a point;
in the figure, 1 denotes a stator core, 2 denotes a stator winding, and 3 denotes a stator case.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. Note that the following description of the embodiments is merely a substantial example, and the present invention is not intended to be limited to the application or the use thereof, and is not limited to the following embodiments.
Examples
As shown in fig. 1 and fig. 2, the present embodiment provides a method for testing mechanical admittance of a stator system of an electric machine, the method including the following steps:
s1, fixing the stator system on a motor workbench, selecting N excitation points on a stator tooth surface according to the circumferential direction, and simultaneously selecting M target points on a casing according to the circumferential direction, wherein the excitation points are uniformly distributed on the stator tooth surface according to the circumferential direction, and the target points are uniformly distributed on the casing according to the circumferential direction;
s2, arranging acceleration sensors at target points respectively;
s3, selecting any one excitation point j, and applying an excitation force P to the excitation pointj(omega) obtaining the acceleration R of each target point respectivelyi(ω) stator system of an electric machine as shown in FIG. 3The transmission of the exciting force is illustrated schematically, wherein P is the exciting force and is transmitted to the stator casing 3 through the stator core 1 and the stator winding 2 in sequence;
s4, assuming that the stator system (the whole of the stator, the winding and the shell) of the motor is linear, and solving the admittance H of the target point i relative to the excitation point jij(ω)：Hij(ω)＝Ri(ω)/Pj(ω); where j is 1,2 … …, N, i is 1,2 … …, M, ω is the angular frequency.
Specifically, the method comprises the following steps: if the force applied to the tooth surface of the motor stator at the 1 point is P1(ω) recording the response of the motor housing measured at point 1 as R1(ω) and the admittance obtained by the two is denoted as H11(ω); if an exciting force P is applied at 1 point1(ω) and the vibration acceleration R is collected at 2 points of the motor casing2(ω) and the admittance obtained by the two is denoted as H12(ω); according to the relation, a transfer equation between the exciting force and the acceleration response of the motor can be established, and a transfer function between the exciting force and the acceleration response is a mechanical admittance matrix of the stator system of the motor. For each element solution of the admittance matrix, the admittance matrix [ H ] can be measured by applying excitation at a single point and collecting response at multiple points]This is the basic principle of testing the mechanical admittance matrix of the stator system of the electrical machine. As shown in the following equations (1) and (2):
Hij(ω)＝Ri(ω)/Pj(ω)(i＝1,2,3,...,M；j＝1,2,3,...,N；) (2)
each element of the admittance matrix [ H ] can be measured by continuously transforming the position of a single excitation point and collecting the response of a relevant point and a non-relevant point. After all elements of all admittance matrices are measured, the transfer equation of the mechanical system can be written as:
in a preferred embodiment, the number of excitation points N is equal to the number of target points M. The excitation points and the target points are uniformly distributed along the circumferential direction and are in one-to-one correspondence with each other, and the pair of excitation points and the target points which are in the corresponding positions are positioned on the same radial straight line. In this case, if the force applied to the tooth surface of the stator of the motor at 1 point is P1(ω) recording the response of the motor housing measured at point 1 as R1(ω) two points are related, so the admittance obtained by both is also called self-admittance and is denoted as H11(ω); if an exciting force P is applied at 1 point1(ω) and the vibration acceleration R is collected at 2 points of the motor casing2(omega) and the two points are non-correlated points, the obtained admittance is mutual admittance and is marked as H12(ω). Thus, it can be seen from the above equation (3) that the elements on the main diagonal correspond to the self-admittance of the stator system of the motor, while the remaining elements correspond to the mutual admittance of the stator system of the motor.
Next, a test experiment of mechanical admittance of a real 48-slot 8-pole interior permanent magnet synchronous motor is performed, and the test method is verified. The mechanical admittance spectrum of the stator system of the test prototype at a certain point is shown in fig. 4. And further, the mechanical admittance spectrum is applied to the vibration characteristic analysis of the motor, and powerful reference is provided for vibration reduction and noise reduction of the motor.
The invention designs a novel method for testing a mechanical admittance matrix of a motor stator system. The method is obtained by constantly searching and summarizing in a motor mode test and a motor vibration noise test. The invention establishes a mathematical model of the mechanical admittance matrix of the motor stator system based on the theory of the mechanical admittance matrix, and solves the mechanical admittance matrix of the motor stator system by applying exciting force to a single point of the tooth surface of a stator and acquiring the acceleration response of the surface of a shell at multiple points. The testing method can effectively test the mechanical admittance matrix frequency spectrum of the motor, is applied to the vibration characteristic analysis of the motor, and provides powerful reference for vibration reduction and noise reduction of the motor. The method can be widely applied to mechanical admittance matrix measurement of various motor stator systems, the measured result has higher accuracy, and the vibration analysis of the motor provides an important basis. Meanwhile, the test method is utilized for analyzing the vibration contribution of a mechanical system of the motor, so that a powerful test reference is provided for reducing the vibration noise of the motor.
At present, the test research on the mechanical admittance matrix of the motor stator system is less, and a complete detailed test method introduction is lacked. But the testing of the mechanical admittance matrix of the motor is an important component in the vibration analysis of the motor at present. The mechanical admittance matrix of the motor stator system can effectively show the vibration characteristics of the motor mechanical system, and the peak position of the mechanical admittance matrix corresponds to the natural frequency of the motor mechanical system and simultaneously contains the mechanical characteristics of the non-natural frequency points. The method has important significance for people to fully know the vibration characteristics of the motor and effectively avoid the frequency band with larger admittance of the motor so as to reduce the vibration of the motor. By the method for testing the motor admittance matrix, the vibration noise and the like of the motor can be effectively reduced.
In actual production, the method for testing the mechanical admittance matrix of the motor stator system can be completely repeated, denser point distribution is adopted, a high-precision vibration acceleration sensor and excellent post-processing software are used, and more accurate mechanical admittance matrix frequency spectrum of the motor stator system can be obtained. The new method for testing the mechanical admittance matrix of the motor has important practical value in the actual motor test, design and production.
Example 2
The embodiment provides a motor stator system mechanical admittance testing arrangement, and the device includes:
vibration exciter: the excitation force sensor is used for applying excitation force to the selected excitation points, and N excitation points are selected and distributed in the circumferential direction of the stator tooth surface;
an acceleration sensor: arranging the target points at the selected target points and measuring the acceleration of the target points, wherein M target points are selected and distributed in the circumferential direction of the shell;
a processor: processing the exciting force and the acceleration to obtain the admittance H of the target point i relative to the exciting point jij(ω)：Hij(ω)＝Ri(ω)/Pj(ω)，Pj(ω) is the excitation force applied at the excitation point j, Ri(ω) is the acceleration of the target point i, j is 1,2 … …, N, i is 1,2 … …, M, ω is the angular frequency.
The excitation points are uniformly distributed on the stator tooth surface according to the circumferential direction.
The target point machine shell is uniformly distributed according to the circumferential direction.
The number N of the excitation points is equal to the number M of the target points.
The excitation points and the target points are uniformly distributed along the circumferential direction and are in one-to-one correspondence with each other, and the pair of excitation points and the target points which are in the corresponding positions are positioned on the same radial straight line.
The method for performing the mechanical admittance test of the motor stator system by adopting the device is the same as that of the embodiment 1, and the description is omitted in the embodiment.
The above embodiments are merely examples and do not limit the scope of the present invention. These embodiments may be implemented in other various manners, and various omissions, substitutions, and changes may be made without departing from the technical spirit of the present invention.
