A three-phase AC permanent magnet synchronous motor parameter measurement method and system

Abstract

The present invention discloses a three-phase AC permanent magnet synchronous motor parameter measurement method and measurement system, the method comprising: setting a companion motor to be measured at a preset speed; operating the measured motor at a preset working point, and reading the preset working point information; reading and storing the voltage information, current information and speed information of the measured motor; generating corresponding voltage deviation information according to the preset working point, wherein the companion motor and the measured motor are both included in the three-phase AC permanent magnet synchronous motor parameter measurement system; according to the voltage information, current information, speed information and voltage deviation information, by calculation, the values ​​of the D-axis inductance Ld, the Q-axis inductance Lq and the motor characteristic current If of the measured motor are obtained; according to the D-axis inductance Ld and the Q-axis inductance Lq, the motor parameter information of the measured motor is generated by interpolation calculation of adjacent working points. This scheme realizes automated testing by manually configuring the working point of the measured motor through a host computer. The current voltage is corrected by importing the voltage deviation information to achieve high-precision motor parameter measurement.

Description

Technical Field

[0001] The invention relates to the field of motor equipment, and in particular to a method and system for measuring parameters of a three-phase AC permanent magnet synchronous motor. Background Art

[0002] The permanent magnet synchronous motor used in electric vehicles needs to have the advantages of wide speed regulation range, high efficiency, and high power density. In order to make the motor run efficiently, it is necessary to obtain all the optimal working points of the motor within the working range, which requires accurate acquisition of motor parameters and calculation of the required optimal working points through motor parameters. In the prior art, there are three common methods: one is to obtain motor parameters through finite element software simulation calculation during the design of permanent magnet motors; the second is to measure motor parameters through current injection method; the third is to calculate motor parameters through the current working point voltage, current and speed. There are the following problems in the above three methods: first, there are differences between the actual motor and the simulated motor, and the parameter accuracy is poor; second, the measurement accuracy cannot meet the accuracy requirements for torque calculation; third, there are too few working points, the measurement efficiency is too low, and the parameter accuracy cannot meet the requirements. Therefore, how to improve the measurement accuracy of motor parameters is very important. Summary of the invention

[0003] The main purpose of the present invention is to provide a method for measuring parameters of a three-phase AC permanent magnet synchronous motor, aiming to solve the technical problem of improving the measurement accuracy of motor parameters.

[0004] The present invention provides a method for measuring parameters of a three-phase AC permanent magnet synchronous motor, comprising:

[0005] The motor under test is operated at a preset working point and the preset working point information is read;

[0006] Read and store the voltage information, current information and speed information of the motor under test, and generate corresponding voltage deviation information according to the preset working point, wherein the accompanying motor and the motor under test are both included in the three-phase AC permanent magnet synchronous motor parameter measurement system;

[0007] According to the voltage information, current information, speed information and voltage deviation information, the values ​​of the D-axis inductance Ld, the Q-axis inductance Lq and the motor characteristic current If of the motor under test are obtained by calculation;

[0008] According to the D-axis inductance Ld and the Q-axis inductance Lq, the motor parameter information of the measured motor is generated by interpolation calculation of adjacent working points.

[0009] Preferably, before the step of setting the accompanying test motor to a preset speed, the method includes:

[0010] According to the accuracy requirements and the equal step method, the two parameters of the current effective value Is and the current phase angle langle are set, and the preset working point information is set.

[0011] Preferably, after the step of generating the motor parameter information of the motor under test by interpolation calculation of adjacent working points according to the D-axis inductance Ld and the Q-axis inductance Lq, the method further comprises:

[0012] The motor parameters of the required operating point are calculated by interpolating adjacent operating points.

[0013] Preferably, the step of reading and storing the voltage information, current information and speed information of the motor under test includes:

[0014] The current voltage value, current value and speed value of the motor under test are read multiple times respectively, and the current voltage value, current value and speed value are filtered respectively to generate and store voltage information, current information and speed information.

[0015] Preferably, the step of obtaining the values ​​of the D-axis inductance Ld, the Q-axis inductance Lq and the motor characteristic current If of the motor under test by calculation according to the voltage information, the current information, the speed information and the voltage deviation information comprises:

[0016] Perform a short-circuit test on the motor under test to obtain the motor characteristic value If;

[0017] According to the first preset algorithm, the Q-axis inductance Lq is calculated:

[0018] Lq=-((UdReal-UdErr))-Rs*Id) / ωe / Iq—— (1);

[0019] Among them, UdReal is the D-axis voltage of the motor under test stored in the host computer, UdErr is the D-axis deviation voltage of the motor under test at the corresponding working point, Rs is the stator resistance of the motor, ωe is the electrical angular velocity of the motor, Id is the D-axis current of the motor under test, and Iq is the Q-axis current of the motor under test;

[0020] According to the second preset algorithm, the D-axis inductance Ld is calculated:

[0021] Ld=((UqReal-UqErr)-Rs*Iq) / ωe / (Id+If)—— (2);

[0022] Among them, UqReal is the Q-axis voltage of the measured motor stored in the host computer, and UqErr is the Q-axis deviation voltage of the measured motor at the corresponding working point.

[0023] The present invention also provides a three-phase AC permanent magnet synchronous motor parameter measurement system, comprising:

[0024] The motor under test;

[0025] Companion motor, used to limit the speed of the motor under test;

[0026] Host computer, used to control each device in the measurement system;

[0027] The motor controller is used to receive the command information from the host computer and drive the motor under test according to the command information.

[0028] The beneficial effects of the present invention are: by manually configuring the working point of the motor under test, automatic testing is realized through a host computer, and by importing the voltage deviation information of the corresponding working point to correct the current voltage, high-precision motor parameter measurement is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic flow chart of a first embodiment of a method for measuring parameters of a three-phase AC permanent magnet synchronous motor according to the present invention;

[0030] Figure 2 It is a structural schematic diagram of a first embodiment of a three-phase AC permanent magnet synchronous motor parameter measurement system of the present invention;

[0031] Figure 3 for Figure 1 The preset working point table in the embodiment;

[0032] Figure 4 for Figure 1 A table of voltage information, current information and speed information of the motor under test stored in the host computer in the embodiment;

[0033] Figure 5 for Figure 1 Voltage deviation table in the embodiment;

[0034] Figure 6 for Figure 1 Schematic diagram of current coordinates in an embodiment.

[0035] Description of labels:

[0036] 1. Motor under test; 2. Motor under test; 3. Host computer; 4. Motor controller.

[0037] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0038] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0039] Reference Figures 1 to 6 The present invention provides a method for measuring parameters of a three-phase AC permanent magnet synchronous motor, comprising:

[0040] S1: Setting the test motor 2 to a preset speed;

[0041] S2: operate the motor under test at a preset working point and read the preset working point information;

[0042] S3: reading and storing voltage information, current information and speed information of the motor under test 1, and generating corresponding voltage deviation information according to a preset working point, wherein the accompanying motor 2 and the motor under test 1 are both included in the three-phase AC permanent magnet synchronous motor parameter measurement system;

[0043] S4: according to the voltage information, the current information, the speed information and the voltage deviation information, the values ​​of the D-axis inductance Ld, the Q-axis inductance Lq and the motor characteristic current If of the motor 1 under test are obtained by calculation;

[0044] S5: Generate motor parameter information of the measured motor 1 through interpolation calculation of adjacent working points according to the D-axis inductance Ld and the Q-axis inductance Lq.

[0045] In the embodiment of the present invention, Figure 2 As shown, the three-phase AC permanent magnet synchronous motor parameter measurement system includes a test motor 2, a measured motor 1, a host computer 3 and a motor controller 4. First, the host computer 3 sets the test motor at a preset speed. Then, the host computer 3 reads the preset working point information. Specifically, the preset working point information is as follows: Figure 3 The upper computer 3 reads the preset working point table, and the user sets the upper computer parameters, such as the interval working point, the data storage location, the number of data readings, and other parameters. The user issues a run command, and the upper computer 3 automatically runs according to the table and the set parameters. The upper computer 3 reads the D-axis voltage UdReal, Q-axis voltage UqReal, and current speed value we of the motor 1 under test according to the set parameters, and the upper computer records and saves them in order. Figure 4 In the Excel table shown. Due to the influence of the inverter dead time and nonlinear factors in the motor controller 4, there is a deviation between the voltage read by the host computer 3 and the actual voltage. The deviation needs to be reduced to calculate the motor parameters with high precision, and the corresponding voltage deviation data is produced for each expected working point. The acquisition of deviation data can be achieved by calibration or other methods. The voltage deviation table is as follows Figure 5 As shown. According to the voltage information, current information, speed information and voltage deviation information, the values ​​of the D-axis inductance Ld, the Q-axis inductance Lq and the motor characteristic current If of the motor under test are obtained through MATLAB calculation. According to the D-axis inductance Ld and the Q-axis inductance Lq, the motor parameter information of the motor under test 1 is generated by interpolation calculation of adjacent working points. After the above settings, the working point of the motor under test 1 is manually configured, and the automatic test is realized through the host computer 3. The current voltage is corrected by importing the voltage deviation information of the corresponding working point to achieve high-precision motor parameter measurement.

[0046] Furthermore, before step S1 of setting the accompanying motor 2 to a preset speed, the method includes:

[0047] S0: Set the two parameters of current effective value Is and current phase angle langle according to the accuracy requirements and equal step size method, and set the preset working point information.

[0048] In the embodiment of the present invention, Figure 3 As shown in the figure, the working point setting mainly includes two parameters: the effective value of current Is and the current phase angle langle. Among them, the current phase angle is defined as:

[0049] langle=-atan(Id / Iq)PI*180

[0050] Among them, atan is the inverse tangent function, Id is the D-axis current value of the motor under test, Iq is the Q-axis current value of the motor under test, and PI is the pi.

[0051] like Figure 3 and 6 As shown in the figure, in order to meet the requirements of the full range of motor operation, the expected working point table should cover the second quadrant working point, Id from 0 to the negative maximum current, Iq from 0 to the maximum current. Set the current effective value step and current phase angle step according to the data accuracy requirements. Edit the table according to the requirements of the host computer software, and finally form a working point preset table that can be used.

[0052] Further, after step S5 of generating motor parameter information of the motor 1 under test by interpolating the D-axis inductance Ld and the Q-axis inductance Lq through adjacent working points, the method includes:

[0053] S6: Calculate the motor parameters at the required operating point by linear interpolation.

[0054] In the embodiment of the present invention, the motor parameter table is mapped to the current coordinates, and the parameters of two adjacent working points are linearly interpolated to obtain the motor parameters of any working point.

[0055] Furthermore, step S3 of reading and storing the voltage information, current information and speed information of the motor under test includes:

[0056] S31: respectively reading the current voltage value, current value and speed value of the motor under test for multiple times, and filtering the current voltage value, current value and speed value respectively, to generate and store voltage information, current information and speed information.

[0057] In the embodiment of the present invention, in order to obtain a more accurate signal, the current voltage value, current current value and speed current value of the measured motor are read multiple times and filtered, and the number of filtering processes can be set by the host computer 3. After the host computer 3 runs, the voltage information, current information and speed information are automatically saved.

[0058] Further, according to the voltage information, current information, speed information and voltage deviation information, step S4 of calculating and obtaining the values ​​of the D-axis inductance Ld, the Q-axis inductance Lq and the motor characteristic current If of the motor under test comprises:

[0059] S41: Perform a short-circuit test on the motor under test to obtain the motor characteristic value If;

[0060] S42: Calculate the Q-axis inductance Lq according to the first preset algorithm:

[0061] Lq=-((UdReal-UdErr))-Rs*Id) / we / Iq—— (1);

[0062] Among them, UdReal is the D-axis voltage of the measured motor 3 stored in the host computer, UdErr is the D-axis deviation voltage of the measured motor 3 at the corresponding working point, Rs is the stator resistance of the motor, we is the electrical angular velocity of the motor, Id is the D-axis current of the measured motor 3, and Iq is the Q-axis current of the measured motor 3;

[0063] S43: Calculate the D-axis inductance Ld according to the second preset algorithm:

[0064] Ld=((UqReal-UqErr)-Rs*Iq) / we / (Id+If)—— (2);

[0065] Among them, UqReal is the Q-axis voltage of the measured motor 3 stored in the host computer, and UqErr is the Q-axis deviation voltage of the measured motor 3 at the corresponding working point;

[0066] In the embodiment of the present invention, each working point is calculated using Formula 1 and Formula 2 to obtain motor parameter information, that is, a motor parameter table.

[0067] like Figure 2 The present invention further provides a three-phase AC permanent magnet synchronous motor parameter measurement system, comprising:

[0068] Motor under test 1;

[0069] The companion motor 2 is used to limit the speed of the motor 1 under test;

[0070] Host computer 3, used to control each device in the measurement system;

[0071] The motor controller 4 is used to receive the command information from the host computer 3 and drive the motor 1 under test according to the command information.

[0072] In the embodiment of the present invention, Figure 2 As shown, the three-phase AC permanent magnet synchronous motor parameter measurement system includes a test motor 2, a measured motor 1, a host computer 3 and a motor controller 4. First, the host computer 3 sets the test motor at a preset speed. Then, the host computer 3 reads the preset working point information. Specifically, the preset working point information is as follows: Figure 3 The upper computer 3 reads the preset working point table, and the user sets the upper computer parameters, such as the interval working point, the data storage location, the number of data readings, and other parameters. The user issues a run command, and the upper computer 3 automatically runs according to the table and the set parameters. The upper computer 3 reads the D-axis voltage Ud, Q-axis voltage Uq, and current speed value S of the motor 1 under test according to the set parameters, and the upper computer records and saves them in order. Figure 4 In the Excel table shown. Due to the influence of the inverter dead time and nonlinear factors in the motor controller 4, there is a deviation between the voltage read by the host computer 3 and the actual voltage. The deviation needs to be reduced to calculate the motor parameters with high precision, and the corresponding voltage deviation data is produced for each expected working point. The acquisition of deviation data can be achieved by calibration or other methods. The voltage deviation table is as follows Figure 5 As shown. According to the voltage information, current information, speed information and voltage deviation information, the values ​​of the D-axis inductance Ld, Q-axis inductance Lq and motor characteristic current If of the motor under test are obtained through MATLAB calculation. According to the D-axis inductance Ld and the Q-axis inductance Lq, the motor parameter information of the motor under test is generated by interpolation calculation of adjacent working points. After the above settings, the working point of the motor under test 1 is manually configured, and the automatic test is realized through the host computer 3. The current voltage is corrected by importing the voltage deviation information of the corresponding working point to achieve high-precision motor parameter measurement.

[0073] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for measuring parameters of a three-phase AC permanent magnet synchronous motor, characterized in that: include: According to the accuracy requirements and the equal step length method, the two parameters of the current effective value Is and the current phase angle langle are set, and the preset working point information is set; The companion motor is set to a preset speed to limit the speed of the motor being tested; The motor under test is operated at a preset working point and the preset working point information is read; Read and store the voltage information, current information and speed information of the motor under test, and generate corresponding voltage deviation information according to the preset working point, wherein the accompanying motor and the motor under test are both included in a three-phase AC permanent magnet synchronous motor parameter measurement system; According to the voltage information, the current information, the speed information and the voltage deviation information, the values ​​of the D-axis inductance Ld, the Q-axis inductance Lq and the motor characteristic current If of the motor under test are obtained by calculation; Generating motor parameter information of the motor under test by interpolation calculation of adjacent working points according to the D-axis inductance Ld and the Q-axis inductance Lq; The step of obtaining the values ​​of the D-axis inductance Ld, the Q-axis inductance Lq and the motor characteristic current If of the motor under test by calculation according to the voltage information, the current information, the speed information and the voltage deviation information comprises: Performing a short-circuit test on the motor under test to obtain the motor characteristic value If; According to the first preset algorithm, the Q-axis inductance Lq is calculated: L q = -(( Ud eal - UdErr ) - Rs * Id ) / we / Iq ——(1); Wherein, UdReal is the D-axis voltage of the motor under test stored in the host computer, UdErr is the D-axis deviation voltage of the motor under test at the corresponding working point, Rs is the stator resistance of the motor, we is the electrical angular velocity of the motor, Id is the D-axis current of the motor under test, and Iq is the Q-axis current of the motor under test; According to the second preset algorithm, the D-axis inductance Ld is calculated: L d =(( U q R eal - QUR ) - Rs * Iq ) / we / ( Id +If )——(2); Wherein, UqReal is the Q-axis voltage of the motor under test stored in the host computer, and UqErr is the Q-axis deviation voltage of the motor under test at the corresponding working point.

2. The three-phase AC permanent magnet synchronous motor parameter measurement method according to claim 1, characterized in that: After the step of generating the motor parameter information of the motor under test by interpolation calculation of adjacent working points according to the D-axis inductance Ld and the Q-axis inductance Lq, the method further comprises: The motor parameters of the required operating point are calculated by interpolating adjacent operating points.

3. The three-phase AC permanent magnet synchronous motor parameter measurement method according to claim 1, characterized in that: The step of reading and storing the voltage information, current information and speed information of the motor under test comprises: The current voltage value, current value and speed value of the motor under test are read multiple times respectively, and the current voltage value, current value and speed value are filtered respectively to generate and store the voltage information, current information and speed information.

4. A measurement system using the three-phase AC permanent magnet synchronous motor parameter measurement method as described in any one of claims 1 to 3, characterized in that: include: The motor under test; A companion motor for measuring, used for limiting the rotation speed of the motor under measuring; Host computer, used to control each device in the measurement system; The motor controller is used to receive the command information of the host computer and drive the motor under test according to the command information.

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