A method for testing the self-inductance and mutual inductance of windings of a symmetrical five-phase permanent magnet synchronous motor

Abstract

The present invention discloses a method for testing the self-inductance and mutual inductance of windings of a symmetrical five-phase permanent magnet synchronous motor. The method is based on an AC static method, and a plurality of DC power supplies are used to apply DC current to the winding ends. In the process of completing the test, the rotor position is adjusted to equivalently consider the influence of the saturation state of the magnetic circuit under the running state on the self-inductance and mutual inductance of the windings. In the process of the test, the influence of the control mode of the actual motor drive circuit on the self-inductance and mutual inductance of the windings is considered. Finally, according to the electromagnetic field equivalent principle, the results of multiple indirect tests are calculated and analyzed to obtain the equivalent measured self-inductance and mutual inductance of the windings under the state of no mechanical load. The present invention does not need to install a mechanical fixing device separately, and can consider the influence of the electromagnetic field on the inductance test results in the running state of the motor. During the test, the housing and shaft extension of the motor do not need to be specially fixed, and no external equipment is required. The method has the characteristics of simple structure, stable performance, and reliable data.

Description

Technical Field

[0001] The invention belongs to the technical field of motor testing, takes a symmetrical five-phase permanent magnet synchronous motor as an application object, and relates to a method for testing the self-inductance and mutual inductance of a symmetrical five-phase permanent magnet synchronous motor winding, in particular to a method for testing the self-inductance and mutual inductance of a symmetrical five-phase permanent magnet synchronous motor winding taking the motor running state into consideration. Background Art

[0002] At present, there are many methods for testing the inductance of permanent magnet synchronous motors, such as DC bridge test, flux linkage test, static torque test, AC static test, etc. Among them, the AC static test can relatively conveniently and accurately test the inductance of the motor winding, and the test method is easy to implement. However, there are also some problems in measuring inductance using the traditional AC static method. For example, in general, when using the AC static method to measure the inductance of the permanent magnet synchronous motor winding, an external stalling device is required to fix the rotor of the motor, which invisibly increases the equipment conditions required for the test, and the actual operating status of the motor cannot be taken into account during the AC static test. Summary of the invention

[0003] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a symmetrical five-phase permanent magnet synchronous motor winding self-inductance and mutual inductance testing method that can take into account the motor operating state. The proposed testing method completes the test of motor winding self-inductance and mutual inductance based on the AC static method, does not require the installation of additional mechanical fixing devices, and can take into account the influence of the electromagnetic field on the inductance test results in the motor operating state.

[0004] In order to solve the above technical problems, a method for testing the self-inductance and mutual inductance of a symmetrical five-phase permanent magnet synchronous motor winding is provided in the present invention, comprising the following steps: selecting any phase winding as the B-phase winding, and starting from the B-phase winding, recording the B-phase, C-phase, D-phase, E-phase and A-phase in a counterclockwise manner;

[0005] Step 1: Add a DC power input 1 between the AC phase windings of the motor, and the DC power input 1 provides a constant DC current of I1. At the same time, add a DC power input 2 between the AD phase windings of the motor, and the DC power input 2 provides a constant DC current of I2 to generate an electromagnetic torque that fixes the rotor and simulate the electromagnetic field distribution inside the motor when the motor is running;

[0006] Step 2: Connect the lead wire of the motor B phase winding to the single-phase output terminal of the frequency converter, supply AC power of a predetermined frequency to the motor B phase, adjust the voltage to the rated voltage through the voltage regulator, and record the test data at the current moment, wherein the test data includes the terminal voltage of the motor B and E two-phase windings, the B phase winding current and the B phase winding electric power;

[0007] Step 3: Stop energizing the B-phase winding, change the magnitude of I1 and I2 or change the magnitude and direction of I1 and I2 at the same time, and then repeat steps 1 and 2. The currents I1 and I2 satisfy I1+I2=I q , I q is the quadrature axis current value when the motor is running. The setting number of repetitions is changed to obtain the self-inductance of the B-phase winding when the motor rotor is in different positions. The self-inductance of the B-phase winding is recorded as the reference value of the motor winding self-inductance L BB1 ;

[0008] Step 4: The B phase winding is energized again, and a DC power input 1 is added between the AE phase windings of the motor, and the DC power input 1 provides a constant DC current of I3. At the same time, a DC power input 2 is added between the AD phase windings of the motor, and the DC power input 2 provides a constant DC current of I4 to generate an electromagnetic torque that fixes the rotor, and at the same time simulate the electromagnetic field distribution inside the motor when the motor is running;

[0009] Step 5: Connect the lead wire of the motor B-phase winding to the single-phase output terminal of the inverter, pass AC power of a predetermined frequency to the motor B-phase winding, adjust the voltage to the rated voltage through the voltage regulator, and record the test data at the current moment, wherein the test data includes the terminal voltage of the motor B and C two-phase windings, the B-phase current and the B-phase electric power;

[0010] Step 6: Stop energizing the B-phase winding, change the magnitude of I3 and I4 or change the magnitude and direction of I3 and I4 at the same time, and then repeat steps 4 and 5. The currents I3 and I4 satisfy I3+I4=I q , I q is the quadrature axis current value when the motor is running, and the setting number of repetitions is changed in total to test and obtain the self-inductance of the B-phase winding when the motor rotor is in different positions. The self-inductance of the B-phase winding is recorded as the reference value of the motor winding self-inductance;

[0011] Step 7: According to the actual driving mode of the permanent magnet synchronous motor and the winding self-inductance reference L BB1 and L BB2 The test data obtained in step 2 and step 5 are used to obtain the winding self-inductance, the mutual inductance between separated windings, and the mutual inductance between adjacent windings taking into account the operating state of the motor.

[0012] Furthermore, the self-inductance of the B-phase winding in step 3 is:

[0013]

[0014] Among them, L BB1 is the self-inductance of the B-phase winding, U B1 ,I B1are the effective values ​​of voltage and current of the B-phase winding obtained according to the test data in step 2, ω is the angular frequency of the sinusoidal alternating current, and P is the copper loss of the winding.

[0015] Furthermore, the self-inductance of the B-phase winding in step 6 is:

[0016]

[0017] Among them, L BB2 is the self-inductance of the B-phase winding, U B2 ,I B2 are the voltage effective value and current effective value of the B-phase winding obtained according to the test data in step 5, ω is the angular frequency of the sinusoidal alternating current, and P is the winding copper loss.

[0018] Furthermore, in step 7, the winding self-inductance considering the motor running state is specifically:

[0019] L S =aL BB1 +bL BB2

[0020] Among them, a is the proportion of the upper and lower bridge arms in the alternate phase conduction mode when the five-phase permanent magnet synchronous motor adopts the space vector control control strategy, and b is the proportion of the upper and lower bridge arms in the adjacent phase conduction mode when the five-phase permanent magnet synchronous motor adopts the space vector control control strategy.

[0021] Furthermore, in step 7, the mutual inductance between the separated windings considering the motor running state is specifically:

[0022]

[0023] Where ω is the angular frequency of the sinusoidal alternating current, U E is the effective value of the voltage of the E-phase winding obtained according to the test data in step 2, I B1 is the effective value of the current of the B-phase winding obtained based on the test data in step 2.

[0024] Furthermore, in step 7, the mutual inductance between adjacent windings considering the motor running state is specifically:

[0025]

[0026] Where ω is the angular frequency of the sinusoidal alternating current, U C is the effective value of the voltage of the C phase winding obtained according to the test data in step 5, I B2 is the effective value of the current of the B-phase winding obtained according to the test data in step five.

[0027] Beneficial effects of the present invention: The present invention utilizes the multi-winding structural characteristics of a symmetrical five-phase permanent magnet synchronous motor and combines the AC static method to test the self-inductance of the motor winding and its mutual inductance with adjacent windings and the mutual inductance of alternate windings. By using this method to test the self-inductance and mutual inductance of the motor winding, the self-inductance of a phase winding and its mutual inductance with adjacent windings and the mutual inductance of alternate windings can be tested when the motor is in any position while considering the operating state of the motor. It not only eliminates the need for an external rotor blocking device, but also improves the test accuracy of the motor's self-inductance and mutual inductance, making it closer to the true value of the motor's self-inductance and mutual inductance under the motor's operating state. In the process of testing the motor inductance using the method of the present invention, the motor casing and shaft extension do not need to be specially fixed, and no external equipment is required. It has a series of advantages such as simple structure, stable performance, and reliable data, and can meet the general needs of motor inductance testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The circuit connection diagram described in step 1 of the method of the present invention;

[0029] Figure 2 The circuit connection diagram described in step 2 of the method of the present invention;

[0030] Figure 3 The circuit connection diagram described in step 4 of the method of the present invention;

[0031] Figure 4 The circuit connection diagram described in step 5 of the method of the present invention;

[0032] Figure 5 Schematic diagram of the structure of the symmetrical five-phase permanent magnet synchronous motor of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0034] Embodiment 1:

[0035] A method for testing the self-inductance of a permanent magnet synchronous motor winding and the mutual inductance between windings of the present invention comprises the following steps:

[0036] Step 1: Add a DC power input 1 between the AC phase windings of the motor, and the DC power input 1 is used to provide a constant DC current of I1. At the same time, add a DC power input 2 between the AD phase windings of the motor, and the DC power input 2 is used to provide a constant DC current of I2 to generate an electromagnetic torque to fix the rotor, and at the same time simulate the electromagnetic field distribution inside the motor when the motor is running;

[0037] Step 2: Connect the B-phase lead wire of the motor to the single-phase output terminal of the inverter, supply AC power of a predetermined frequency to the B-phase of the motor, adjust the voltage to the rated voltage through the voltage regulator, and record the test data at the current moment. The test data includes the terminal voltage of the two-phase windings of the motor B and E, the B-phase current and the B-phase electric power.

[0038] Step 3: Stop the power supply, change the direction and magnitude of the input currents I1 and I2, and the currents I1 and I2 satisfy I1+I2=I q (I q is the cross-axis current value when the motor is running) and then repeat steps 1 and 2 to test the self-inductance of the B-phase winding and the mutual inductance between the BE-phase windings when the motor rotor is in different positions. The self-inductance of the B-phase winding at this time is recorded as the motor's winding self-inductance reference value 1, and the mutual inductance between the BE-phase windings is recorded as the mutual inductance between the separated windings.

[0039] Step 4: Restart powering on, add a DC power input 1 between the AE phase windings of the motor, the DC power input 1 is used to provide a constant DC current of I3, and at the same time, add a DC power input 2 between the AD phase windings of the motor, the DC power input 2 is used to provide a constant DC current of I4, so as to generate an electromagnetic torque to fix the rotor, and at the same time simulate the electromagnetic field distribution inside the motor when the motor is running;

[0040] Step 5: Connect the B-phase lead wire of the motor to the single-phase output terminal of the inverter, supply AC power of a predetermined frequency to the B-phase of the motor, adjust the voltage to the rated voltage through the voltage regulator, and record the test data at the current moment. The test data includes the terminal voltage of the two-phase windings of the motor B and C, the B-phase current and the B-phase electric power.

[0041] Step 6: Stop the power supply, change the direction and magnitude of the input currents I3 and I4, and the currents I3 and I4 satisfy I3+I4=I q (I q is the cross-axis current value when the motor is running), and then repeat steps 4 and 5 to test the self-inductance of the B-phase winding and the mutual inductance between the BC-phase windings when the motor rotor is in different positions. The self-inductance of the B-phase winding at this time is recorded as the motor's winding self-inductance reference 2, and the mutual inductance between the BC-phase windings is recorded as the mutual inductance between adjacent windings.

[0042] Step 7: According to the actual driving mode of the permanent magnet synchronous motor and the winding self-inductance reference 1 and the winding self-inductance reference 2 in step 3 and step 6, the winding self-inductance, the mutual inductance between adjacent windings, and the mutual inductance between separated windings considering the motor running state can be obtained.

[0043] Embodiment 2:

[0044] like Figure 1 to Figure 5As shown, a method for testing the self-inductance of a permanent magnet synchronous motor winding and the mutual inductance between windings involved in this embodiment comprises the following steps:

[0045] Step 1: Add a DC power input 1 between the AC phase windings of the motor unit, and the DC power input 1 is used to provide a constant DC current of I1. At the same time, add a DC power input 2 between the AD phase windings of the motor unit, and the DC power input 2 is used to provide a constant DC current of I2 to generate an electromagnetic torque to fix the rotor and simulate the electromagnetic field distribution inside the motor when the motor is running. The specific electrical connection is as follows Figure 1 shown.

[0046] Step 2: Connect the B-phase lead wire of the motor to the single-phase output terminal of the inverter, supply AC power of a predetermined frequency to the B-phase of the motor, adjust the voltage to the rated voltage through the voltage regulator, and record the test data at the current moment, which includes the terminal voltage of the B and E-phase windings of the motor, the B-phase current and the B-phase electric power. The specific electrical connection is as follows: Figure 2 shown.

[0047] Step 3: Stop the power supply, change the direction and magnitude of the input currents I1 and I2, and the currents I1 and I2 satisfy I1+I2=I q (I q is the quadrature axis current value when the motor is running), and then repeat steps 1 and 2 to test the self-inductance of the B-phase winding and the mutual inductance between the BE-phase windings when the motor rotor is in different positions. The self-inductance of the B-phase winding at this time is recorded as the motor winding self-inductance reference value L BB1 , the mutual inductance between the BE phase windings is recorded as the mutual inductance between the separated windings L BE .

[0048] Calculation of the self-inductance and mutual inductance of the permanent magnet synchronous motor winding under the test method of the present invention:

[0049] The voltage equation of the symmetrical five-phase permanent magnet synchronous motor winding can be written in the following matrix form:

[0050]

[0051] Among them, u=[u A u B u C u D u E ],i=[i A i B i C i D i E ],ψ=L·i,

[0052]

[0053] Then the voltage equation of the jth winding is:

[0054]

[0055] in, L jj is the self-inductance of the jth winding, L kj The mutual inductance between the kth winding and the jth winding.

[0056] In fact, the self-inductance and mutual inductance of the winding are both the rotor position angle θ r function, so formula (2) can be written as follows:

[0057]

[0058] When using the static measurement method to determine the winding inductance parameters, the motor rotor is fixed and does not move. Then formula (3) can be simplified to

[0059]

[0060] At this time, a sinusoidal alternating current i is passed through the jth winding. j , when the kth winding is open. Then the voltage equation of the jth winding and the kth winding can be written as

[0061]

[0062]

[0063] Write the above formula in plural form

[0064] U j =r j I j +jωL jj I j

[0065] U k =jωL kj I j

[0066] Among them, U j , U k , I j are the effective values ​​of the corresponding voltage and current, and ω is the angular frequency of the sinusoidal alternating current.

[0067] When the motor rotor is fixed at a certain rotor position angle θ r When the self-inductance of the jth winding is

[0068]

[0069] In actual measurement, by measuring the winding copper loss P and current I j , the resistance of the winding can be obtained as follows

[0070]

[0071] Then the self-inductance of the jth winding can be expressed as

[0072]

[0073] The mutual inductance between the jth winding and the kth winding is

[0074]

[0075] According to the above formula, a sinusoidal alternating current i is passed through the jth winding. j , and when the kth winding is open, the current of the jth winding, the voltage of the jth winding, the power of the jth winding and the voltage of the kth winding can be measured to calculate the self-inductance of the jth winding and the mutual inductance between the kth winding and the jth winding.

[0076] Step 4: Restart powering on, add DC power input 1 between the AE phase windings of the motor unit, the DC power input 1 is used to provide a constant DC current of I3, and at the same time, add DC power input 2 between the AD phase windings of the motor unit, the DC power input 2 is used to provide a constant DC current of I4, so as to generate an electromagnetic torque to fix the rotor and simulate the electromagnetic field distribution inside the motor when the motor is running. The specific electrical connection is as follows Figure 3 shown.

[0077] Step 5: Connect the B-phase lead wire of the motor to the single-phase output terminal of the inverter, supply AC power of a predetermined frequency to the B-phase of the motor, adjust the voltage to the rated voltage through the voltage regulator, and record the test data at the current moment, which includes the terminal voltage of the B and C phase windings of the motor, the B-phase current and the B-phase electric power. The specific electrical connection is as follows: Figure 4 shown.

[0078] Step 6: Stop the power supply, change the direction and magnitude of the input currents I3 and I4, and the currents I3 and I4 satisfy I3+I4=I q (I q is the quadrature axis current value when the motor is running), and then repeat steps 4 and 5 to test the self-inductance of the B-phase winding and the mutual inductance between the BC-phase windings when the motor rotor is in different positions. The self-inductance of the B-phase winding at this time is recorded as the motor winding self-inductance reference value L BB2 , the mutual inductance between the BC phase windings is recorded as the mutual inductance between adjacent windings L BC .

[0079] Step 7: According to the actual driving mode of the permanent magnet synchronous motor and the winding self-inductance reference 1 and winding self-inductance reference 2 in step 3 and step 6, the winding self-inductance, the mutual inductance between adjacent windings, and the mutual inductance between separated windings considering the motor running state can be obtained. The specific calculation formula is as follows:

[0080] L S =aL BB1 +bL BB2

[0081] Among them, L S These are the test results of the self-inductance of the windings of a symmetrical five-phase permanent magnet synchronous motor taking into account the operating state of the motor. a is the proportion of the upper and lower bridge arms conducting in alternate phases when the five-phase permanent magnet synchronous motor adopts the space vector control strategy. b is the proportion of the upper and lower bridge arms conducting in adjacent phases when the five-phase permanent magnet synchronous motor adopts the space vector control strategy.

[0082]

[0083] Among them, L m1 The test results of the mutual inductance of the alternate windings of the symmetrical five-phase permanent magnet synchronous motor considering the motor running state, U E and I B1 This is the test result in step 2.

[0084]

[0085] Among them, L m2 The test results of the mutual inductance of adjacent windings of a symmetrical five-phase permanent magnet synchronous motor considering the motor operation state, U C and I B2 This is the test result in step 5.

Claims

1. A method for testing the self-inductance and mutual inductance of windings of a symmetrical five-phase permanent magnet synchronous motor, characterized in that: The following steps are involved: Select any phase winding as the B phase winding, and start from the B phase winding and go counterclockwise as B phase, C phase, D phase, E phase and A phase; Step 1: Add a DC power input 1 between the AC phase windings of the motor, and the DC power input 1 provides a constant DC current of I1. At the same time, add a DC power input 2 between the AD phase windings of the motor, and the DC power input 2 provides a constant DC current of I2 to generate an electromagnetic torque that fixes the rotor and simulate the electromagnetic field distribution inside the motor when the motor is running; Step 2: Connect the lead wire of the motor B phase winding to the single-phase output terminal of the frequency converter, supply AC power of a predetermined frequency to the motor B phase, adjust the voltage to the rated voltage through the voltage regulator, and record the test data at the current moment, wherein the test data includes the terminal voltage of the motor B and E two-phase windings, the B phase winding current and the B phase winding electric power; Step 3: Stop energizing the B-phase winding, change the magnitude of I1 and I2 or change the magnitude and direction of I1 and I2 at the same time, and then repeat steps 1 and 2. The currents I1 and I2 satisfy I1+I2=I q , I q is the quadrature axis current value when the motor is running. The setting number of repetitions is changed to obtain the self-inductance of the B-phase winding when the motor rotor is in different positions. The self-inductance of the B-phase winding is recorded as the reference value of the motor winding self-inductance L BB1 ; Step 4: The B phase winding is energized again, and a DC power input 1 is added between the AE phase windings of the motor, and the DC power input 1 provides a constant DC current of I3. At the same time, a DC power input 2 is added between the AD phase windings of the motor, and the DC power input 2 provides a constant DC current of I4 to generate an electromagnetic torque that fixes the rotor, and at the same time simulate the electromagnetic field distribution inside the motor when the motor is running; Step 5: Connect the lead wire of the motor B-phase winding to the single-phase output terminal of the inverter, pass AC power of a predetermined frequency to the motor B-phase winding, adjust the voltage to the rated voltage through the voltage regulator, and record the test data at the current moment, wherein the test data includes the terminal voltage of the motor B and C two-phase windings, the B-phase current and the B-phase electric power; Step 6: Stop energizing the B-phase winding, change the magnitude of I3 and I4 or change the magnitude and direction of I3 and I4 at the same time, and then repeat steps 4 and 5. The currents I3 and I4 satisfy I3+I4=I q , I q is the quadrature axis current value when the motor is running. The setting number of repetitions is changed to obtain the self-inductance of the B-phase winding when the motor rotor is in different positions. The self-inductance of the B-phase winding is recorded as the reference value of the motor winding self-inductance L BB2 ; Step 7: According to the actual driving mode of the permanent magnet synchronous motor and the winding self-inductance reference L BB1 and L BB2 The test data obtained in step 2 and step 5 are used to obtain the winding self-inductance, the mutual inductance between separated windings, and the mutual inductance between adjacent windings taking into account the operating state of the motor.

2. A method for testing the self-inductance and mutual inductance of windings of a symmetrical five-phase permanent magnet synchronous motor according to claim 1, characterized in that: The self-inductance of the B-phase winding in step 3 is: Among them, L BB1 is the self-inductance of the B-phase winding, U B1 ,I B1 are the effective values ​​of voltage and current of the B-phase winding obtained according to the test data in step 2, ω is the angular frequency of the sinusoidal alternating current, and P is the copper loss of the winding.

3. A method for testing the self-inductance and mutual inductance of windings of a symmetrical five-phase permanent magnet synchronous motor according to claim 1, characterized in that: The self-inductance of the B-phase winding in step 6 is: Among them, L BB2 is the self-inductance of the B-phase winding, U B2 ,I B2 are the effective values ​​of voltage and current of the B-phase winding obtained according to the test data in step 5, ω is the angular frequency of the sinusoidal alternating current, and P is the copper loss of the winding.

4. A method for testing the self-inductance and mutual inductance of windings of a symmetrical five-phase permanent magnet synchronous motor according to claim 1, characterized in that: The winding self-inductance considering the motor running state described in step 7 is specifically: <h2 style=";text-align:left;direction:ltr">L<h2 style=";text-align:left;direction:ltr"> S <h2 style=";text-align:left;direction:ltr"> =aL<h2 style=";text-align:left;direction:ltr"> BB1 <h2 style=";text-align:left;direction:ltr"> +bL<h2 style=";text-align:left;direction:ltr"> BB2 Among them, a is the proportion of the upper and lower bridge arms in the alternate phase conduction mode when the five-phase permanent magnet synchronous motor adopts the space vector control control strategy, and b is the proportion of the upper and lower bridge arms in the adjacent phase conduction mode when the five-phase permanent magnet synchronous motor adopts the space vector control control strategy.

5. A method for testing the self-inductance and mutual inductance of windings of a symmetrical five-phase permanent magnet synchronous motor according to claim 1, characterized in that: The mutual inductance between the separated windings considering the motor running state described in step 7 is specifically: Where ω is the angular frequency of the sinusoidal alternating current, U E is the effective value of the voltage of the E-phase winding obtained according to the test data in step 2, I B1 is the effective value of the current of the B-phase winding obtained based on the test data in step 2.

6. A method for testing the self-inductance and mutual inductance of windings of a symmetrical five-phase permanent magnet synchronous motor according to claim 1, characterized in that: The mutual inductance between adjacent windings considering the motor running state described in step 7 is specifically: Where ω is the angular frequency of the sinusoidal alternating current, U C is the effective value of the voltage of the C phase winding obtained according to the test data in step 5, I B2 is the effective value of the current of the B-phase winding obtained according to the test data in step 5.

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