JP2011012999A - Methods for testing and manufacturing rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a testing method for accurately detecting the contact state between unit coils composing stator coils in each phase.SOLUTION: The method for manufacturing a permanent magnet electric motor includes: a coil mounting step (step 1) of inserting a U-phase coil, a V-phase coil and a W-phase coil into a stator core; a neutral point connecting step (step 2) for forming a neutral point by swage connecting the stator coils of each phase; and a step of performing an in-phase coil impulse discharge test (step 3) for detecting the insulation state between the unit coils of each stator coil. In this impulse discharge test, the insulation abnormality between the unit coils is detected by applying an impulse voltage to stator coils of each phase and by detecting the presence or absence of the occurrence of the partial discharge between the unit coils. Thereafter, a step of forming an electric source terminal (step 4) and a step of conducting an electric test (step 5) for examining the insulation to the earth are performed.

Description

  The present invention relates to a testing method and a manufacturing method for a rotating electrical machine configured by winding a stator coil including a plurality of unit coils around an iron core.

  Conventionally, as an electric motor as a rotating electric machine used for an electric vehicle, a hybrid vehicle, etc., an inverter configured by winding a three-phase stator coil of a plurality of phases, for example, a U phase, a V phase, and a W phase around an iron core (stator core) 2. Description of the Related Art Drive type permanent magnet type motors (hereinafter referred to as permanent magnet motors) are known. Such a permanent magnet motor generally uses a stator coil in which a plurality of unit coils are connected in series. In particular, in order to reduce a shared voltage, a plurality of stator coils (for example, two circuits) are arranged in parallel in each phase. May connect to. FIG. 13 schematically shows a general manufacturing process of such a permanent magnet motor.

  In step 101, U-phase, V-phase, and W-phase stator coils (corresponding to U-phase coils, V-phase coils, and W-phase coils) are mounted (inserted) on the stator core while interphase insulating paper is disposed between the stator coils. ) Is performed. In step 102, a step of caulking and connecting the end portions of each stator coil to form each phase neutral point is performed. In step 103, a process is performed in which the coil end is formed, and is bound and fixed with a binding thread. In step 104, a step of caulking and connecting each stator coil to a terminal for each phase to form a power supply terminal is performed. In step 105, an electrical test process prior to varnish processing for examining the electrical soundness of each stator coil is performed. In step 106, a varnish treatment process is performed on each stator coil for varnish treatment. In step 107, an electrical test process after varnish treatment is performed.

  Among the electrical tests performed in each of the above-described processes, there is a test for confirming the insulation state of the stator coil as in step 105, for example. Specifically, between each phase stator coil (for example, U-phase coil and V) such as an insulation test between the stator coil and the stator core such as a withstand voltage test between grounds and a partial discharge test between grounds and an impulse discharge test. Insulation tests and the like have been carried out for different phase coils such as between phase coils. In such tests, a test method for verifying the insulation between the stator coils by connecting the neutral point of the stator coil at the end of the manufacturing process and conducting an insulation test before connecting the neutral point is proposed. (For example, refer to Patent Document 1).

  By the way, permanent magnet motors such as those used in electric vehicles and hybrid vehicles tend to have higher voltages for higher output, and each stator coil is driven by an inverter surge voltage with a steep rise due to an inverter drive system. There is also a tendency for the shared voltage to increase. For this reason, even within each stator coil (in the same-phase coil), a difference occurs in the voltage shared by the unit coils, and the possibility of partial discharge increases. In particular, the first unit coil and the second unit coil provided on the most power supply terminal side of each stator coil have the largest difference in the shared voltage and are adjacent at the coil end, so that partial discharge occurs. Likely to happen. Further, in the case of a vehicle that is a moving body, the surrounding environment (for example, weather, altitude, etc.) changes as the vehicle travels, so that the possibility of partial discharge is further increased.

  Since the stator coil deteriorates in a short time when partial discharge occurs, in the permanent magnet motor, an insulating paper is inserted between each unit coil, or a dummy wedge is inserted at the time of coil end molding, and the spatial distance between the unit coils. Measures are taken to prevent contact between the unit coils, such as by removing the coil.

JP 2005-80359 A

  However, when insulating paper or a dummy wedge is inserted between the unit coils, verification of the insulation state in the in-phase coil is not performed, such as whether or not contact is surely prevented. In the conventional test method for different phases such as 1, there is a problem that it is difficult to detect the insulation state between the unit coils in the in-phase coil.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a test method for a rotating electrical machine for accurately detecting a contact state between unit coils constituting each stator coil.
Another object of the present invention is to provide a highly reliable method for manufacturing a rotating electrical machine in which there is no contact between unit coils constituting a stator coil.

  The testing method for a rotating electrical machine according to the present invention includes the unit coil of the stator coil in a manufacturing process of a rotating electrical machine configured by winding a plurality of stator coils in which a plurality of unit coils are connected in series to an iron core. A test method for verifying an insulation state between the stator coils of the plurality of phases attached to the iron core, and connecting the stator coils of the respective phases to form neutral points; By applying an impulse voltage by an impulse voltage application device between a point and a power supply terminal of the multi-phase stator coil, the occurrence of partial discharge between the unit coils is partially determined for each of the multi-phase stator coils. An impulse discharge test detected by a discharge detector is performed.

  According to another aspect of the present invention, there is provided a rotating electrical machine manufacturing method comprising: a mounting step of mounting a multi-phase stator coil on the iron core; A neutral point connection step for forming a neutral point by electrically connecting the stator coils, a forming step for forming the multi-phase stator coil, and an electrical test step for performing an electrical test on the stator coil In the electrical test step, the impulse discharge test described above is performed.

  According to the rotating electrical machine test method of the present invention, by detecting the presence or absence of partial discharge by applying an impulse voltage between the neutral point and the power supply terminal for each of the stator coils provided in a plurality of phases. The insulation state between the unit coils in the in-phase coil can be verified.

  Further, according to the method for manufacturing a rotating electrical machine of the present invention, since the impulse discharge test is performed in the manufacturing process, it is possible to manufacture a high-quality rotating electrical machine having no insulation abnormality between unit coils.

The figure which shows schematically the manufacturing process of the permanent magnet electric motor by 1st Embodiment of this invention. Block diagram schematically showing a test apparatus for impulse discharge test Diagram showing equivalent circuit of three-phase stator coil The figure which shows typically the contact state between a 1st unit coil and a 2nd unit coil. The figure which shows the preliminary test result which verifies the discharge start voltage The figure which shows the experimental result of the impulse discharge test with the electromagnetic wave antenna The figure which shows the relationship between the humidity and discharge start voltage by 2nd Embodiment of this invention. The figure which shows the change of the discharge start voltage when the humidity rises The figure which shows the change of the discharge start voltage when the humidity falls FIG. 2 equivalent diagram according to the third embodiment of the present invention. The figure which shows the experimental result of the impulse discharge test with the high frequency current probe The figure which shows the relationship between the amount of discharge charges and applied voltage by 4th Embodiment of this invention. The figure which shows the manufacturing process of the permanent magnet motor by a prior art roughly

(First embodiment)
Hereinafter, a first embodiment in which the present invention is applied to an inverter-driven permanent magnet motor used in an electric vehicle, a hybrid vehicle, and the like will be described with reference to FIGS.

  As shown in FIG. 2, the stator 1 of the permanent magnet motor is configured by winding a three-phase stator coil (that is, a U-phase coil 3, a V-phase coil 4, and a W-phase coil 5) around a stator core 2. . The stator core 2 has an annular shape in which a plurality of core pieces, for example, formed by punching electromagnetic steel sheets with a press or the like are stacked. The stator core 2 is formed with a plurality of slots (not shown) into which three-phase stator coils are inserted on the inner peripheral side thereof. Insulating paper is affixed to the inner peripheral surface of the slot, and slot insulation is provided to insulate the stator core 2 from each stator coil.

  Each stator coil is configured by winding a strand such as an enamel wire or a litz wire in which a plurality of strands are bundled. A U-phase coil 3, a V-phase coil 4, and a W-phase coil 5 are sequentially attached to the stator core 2 from the radially outer side toward the inner peripheral side (hereinafter referred to as U-phase coil 3, V-phase coil 4, W When a matter common to the phase coil 5 is described, it is simply referred to as a stator coil of each phase). Interphase insulating paper 6 is inserted between the stator coils of each phase. A U-phase power supply terminal 7, a V-phase power supply terminal 8, and a W-phase power supply terminal 9, which are power terminals for each phase, are provided on the upper coil end of the stator core 2. The ends of the stator coils opposite to the power supply terminals (7, 8, 9) are electrically connected to each other to form the phase neutral points Na and Nb.

  FIG. 3 shows an equivalent circuit of the stator coil of each phase. The U-phase coil 3 is constituted by a parallel circuit of a coil group 3a formed by connecting four unit coils in series and a coil group 3b formed by connecting four unit coils in series. Similarly, the V-phase coil 4 is composed of a parallel circuit of a coil group 4a in which four unit coils are connected in series and a coil group 4b in which four unit coils are connected in series. 5 is composed of a parallel circuit of a coil group 5a formed by connecting four unit coils in series and a coil group 5b formed by connecting four unit coils in series.

  Each coil group 3a, 4a, 5a is connected to each other at each phase neutral point Na, and each coil group 3b, 4b, 5b is connected to each other at each phase neutral point Nb. That is, in the stator core 2, the coil groups 3a, 4a, 5a and the coil groups 3b, 4b, 5b are arranged in parallel between the power terminals (U-phase power terminal 7, V-phase power terminal 8, W-phase power terminal 9). Connected (double star connection). In the following description, the first unit coil, the second unit coil, the third unit coil, and the fourth unit coil are referred to in order from the unit coil provided at the position closest to the power supply terminal in the stator coil of each phase. When the unit coil is individually described, a suffix (1, 2, 3, 4) is attached to each coil group 3a, 3b, 4a, 4b, 5a, 5b. Further, when the matters common to the coil groups 3a, 3b, 4a, 4b, 5a, and 5b are described, they are simply referred to as the coil groups without reference numerals.

Next, a manufacturing process of the permanent magnet motor having the above-described configuration will be described.
FIG. 1 schematically shows a manufacturing process of the stator 1 (but before the varnish treatment process (step 106) in the conventional manufacturing process shown in FIG. 13) among the manufacturing processes of the permanent magnet motor. In the following description, for the sake of simplification, the flow of the entire manufacturing process including the test process according to the present invention (impulse discharge test in step 3 described later) will be described first, and then the impulse discharge test will be described in detail. explain.

  In Step 1, a U-phase coil 3, a V-phase coil 4, and a W-phase coil 5 are disposed on a stator core 2 that has been previously slot-insulated, and interphase insulating paper 6 is disposed between stator coils of each phase (between coil ends). A coil mounting process for inserting (mounting) is performed. In this step, first, the U-phase coil 3 is attached to the slot of the stator core 2. Subsequently, after the interphase insulating paper 6 is inserted so as to cover the U-phase coil 3, the V-phase coil 4 is mounted in a slot different from the previous one so that the interphase insulating paper 6 is sandwiched between the coil ends. Thereby, the coil ends (between different phases) of the U-phase coil 3 and the V-phase coil 4 are insulated by the interphase insulating paper 6. Next, after the interphase insulating paper 6 is inserted so as to cover the coil end of the V phase coil 4, the W phase coil 5 is mounted in another slot so that the interphase insulating paper 6 is sandwiched between the coil ends. The stator coils for each phase are mounted such that the electrical angles are shifted from each other by 120 °.

  In step 2, a neutral point connection step is performed in which the stator coils of the respective phases are caulked and connected to form the neutral points of the respective phases. In the present embodiment, the coil groups 3a, 4a and 5a are caulked and connected to form each phase neutral point Na, and the coil groups 3b, 4b and 5b are caulked to each other to form each phase neutral point Nb. The

  In step 3, an electrical test process in the in-phase coil by an impulse discharge test is performed in connection with the present invention. In this impulse discharge test, the insulation state between unit coils (such as the presence or absence of contact between unit coils) is verified for each phase of the stator coil. Details of this impulse discharge test will be described later.

  In step 4, the end of each coil group opposite to each phase neutral point Na, Nb is caulked and connected to each phase, U phase power supply terminal 7, V phase power supply terminal 8, W phase power supply terminal 9 ( Hereinafter, a power source side lead wire caulking process is performed, which collectively refers to each phase power terminal. In Step 4, the neutral point connection portion is insulated and placed at a predetermined location on the coil end. Thereafter, the coil ends of the stator coils of the respective phases are formed to a specified size, and a process is performed in which the ends including the caulking connection portions of the neutral points Na and Nb are bound and fixed with a binding thread (not shown).

  In step 5, a coil electrical test process is performed in which various electrical tests such as an insulation resistance / withstand voltage test are performed on the stator coils of each phase. In addition, since each test implemented by a coil electrical test process is a test similar to the past, description is abbreviate | omitted.

  Next, the impulse discharge test according to the present invention in Step 3 will be described in detail. In the following description, the U-phase coil 3 is mainly described as an example, but the same impulse discharge test is also performed on the V-phase coil 4 and the W-phase coil 5.

  FIG. 2 schematically shows the overall configuration of the test apparatus 10 that performs the impulse discharge test. The test apparatus 10 includes an impulse voltage application device 11 and a partial discharge detection device 12. The impulse voltage application device 11 has two output terminals, and either output terminal is provided on the neutral point side and the power supply terminal side of the U-phase coil 3 according to the polarity of the impulse voltage applied to the stator coil. They are connected (between U-phase power supply terminal 7 and neutral point Na or Nb in FIG. 2). As described above, since the phase power supply terminals (7, 8, 9) are not yet formed at the stage of step 3 where the impulse discharge test is performed, the output terminal of the impulse voltage application device 11 is correctly set. Is connected between one of the phase neutral points Na and Nb and either end of the coil group 3a or the coil group 3b. Here, for convenience, the impulse voltage application device 11 is connected. The connection destination of the output terminal is referred to as a neutral point side and a power supply terminal side.

  The partial discharge detection device 12 includes an electromagnetic wave antenna 12a capable of detecting a gigahertz band electromagnetic wave, and a discharge detector 12b connected to the electromagnetic wave antenna 12a. The electromagnetic wave antenna 12a is disposed in the vicinity of a stator coil to be detected, for example, the U-phase coil 3, and detects a gigahertz band electromagnetic wave that is emitted when a partial discharge occurs. The discharge detector 12b displays the electromagnetic wave detected by the electromagnetic wave antenna 12a on, for example, a monitor screen.

  Now, the impulse voltage applied to the stator coil by the impulse voltage application device 11 needs to have such a magnitude that the contact between the strands between the unit coils constituting the stator coil of each phase can be detected. On the other hand, if the applied voltage is too high, the sound stator coil may be damaged. Therefore, when setting the magnitude of the impulse voltage, it is necessary to set it to the minimum voltage value at which partial discharge can be detected. Therefore, in the present embodiment, based on the result of a preliminary test in which a voltage value at which partial discharge occurs is measured using a test coil in which a simulated contact state is generated between unit coils, a stator coil for each phase The magnitude of the impulse voltage applied to is set.

  FIG. 4 is a diagram schematically showing the test coil. For example, in the case of a U-phase test coil, the first turn portion Ts that is the start of winding of the first unit coil 3a1 provided closest to the power supply terminal in the coil group 3a and the winding of the adjacent second unit coil 3a2 A simulated contact state is formed with the final turn portion Te which is the end. Between this 1st unit coil and the 2nd unit coil, the potential difference of the shared voltage by the surge voltage at the time of an actual driving | operation (at the time of inverter drive) becomes the largest, and it is a site | part where partial discharge is most likely to occur. In the impulse discharge test, the presence or absence of a contact state between unit coils is verified.

  FIG. 5 is a diagram illustrating a result of a preliminary test for verifying a discharge start voltage at which a partial discharge occurs. In this preliminary test, using the same wire as the stator coil wound around the stator core 2, using a healthy product coil without contact failure such as contact, and the above-described test coil (see FIG. 4), a positive voltage is applied to them. A test of applying a unipolar impulse voltage is performed. In this preliminary test, the voltage when partial discharge occurs is set as the discharge start voltage. In the example of FIG. 5, it is shown that the partial discharge starts near Va in the healthy coil, and the partial discharge starts near Vb in the test coil.

  When it is desired to detect a partial discharge (insulation abnormality between the first unit coil and the second unit coil) generated between the first unit coil and the second unit coil from the result of the preliminary test, the impulse voltage It can be seen that the size of V should be Vc. That is, if the magnitude of the impulse voltage is Vc, it is possible to detect the occurrence of partial discharge when there is an insulation abnormality, and since the partial discharge does not occur in the healthy coil, it is possible to prevent erroneous detection. It becomes possible to carry out an impulse discharge test. Since the values of Va and Vb vary depending on the coil specifications, Vc may be set appropriately according to the coil specifications.

  FIG. 6 is a diagram showing detection results of electromagnetic waves detected in this impulse discharge test. FIG. 6A shows that insulation between unit coils is normally performed and there is no insulation failure such as contact between unit coils. The result of the healthy product coil is shown, and (B) shows the detection result of the abnormal product coil in which the contact state occurs between the unit coils. When insulation between unit coils is maintained, electromagnetic waves due to partial discharge are not detected as shown in FIG. On the other hand, when there is an insulation abnormality between the unit coils, electromagnetic waves are detected with the occurrence of partial discharge as shown in FIG. Thereby, the insulation abnormality between unit coils is verified.

  In this impulse discharge test, of the output terminals of the impulse voltage application device 11, the positive side output terminal is connected to, for example, the U-phase power supply terminal (7) side, and the negative side output terminal is connected to the neutral point side. After detecting the presence or absence of the discharge state between them, the impulse voltage is applied by connecting the negative phase, that is, the positive output terminal to the neutral point side and the negative output terminal to the U phase power supply terminal (7) side. ing. Similarly, the V-phase coil 4 and the W-phase coil 5 were tested after connecting the positive output terminal to the power supply terminal (8, 9) side and the negative output terminal to the neutral point side. A test at will be conducted. Thereby, the shared voltage between unit coils is equalized as much as possible.

  As described above, by performing the impulse discharge test on the stator coil of each phase, the insulation abnormality in the stator coil of each phase, for example, between the first unit coil and the second unit coil can be reduced. It becomes possible to verify with high accuracy in the manufacturing process.

  Thereafter, the stator 1 is formed through each process (corresponding to steps 105 to 107 in FIG. 13) such as a varnish treatment process. The stator 1 that has passed each electrical test constitutes a permanent magnet motor through an assembly process together with a rotor (not shown) having a plurality of permanent magnets as magnetic poles. In this way, a permanent magnet electric motor is produced in which there is no insulation abnormality between the unit coils of each phase (in the same phase coil) and between the stator coils of each phase (between different phase coils).

According to the first embodiment described above, the following effects can be obtained.
In the impulse discharge test process (step 3), an impulse discharge test is performed to verify the occurrence of partial discharge by applying an impulse voltage between the neutral point side and the power supply terminal side. Thereby, since partial discharge occurs when there is an insulation abnormality, it is possible to detect insulation abnormality such as contact between unit coils constituting each stator coil.

  In the impulse discharge test, the magnitude of the impulse voltage is preliminarily tested with a test coil, so that partial discharge may occur due to the surge sharing voltage between unit coils during actual operation. When there is an insulation abnormality, the occurrence of partial discharge can be detected, and the value is set so that partial discharge does not occur in a healthy coil. As a result, the impulse voltage can be set to the minimum necessary level capable of detecting the partial discharge, and the possibility that the stator coil is damaged by the impulse discharge test can be reduced. Moreover, since a voltage larger than necessary is not applied, damage to the stator coil during the impulse discharge test can be prevented, and as a result, the reliability of the permanent magnet motor can be improved.

  In the impulse discharge test, the impulse voltage was set to a magnitude that can detect an insulation abnormality between the first unit coil and the second unit coil, in which the shared voltage due to the inverter surge voltage is concentrated and the potential difference becomes the largest.

  Since the impulse discharge test is performed after the coil end is formed, the test can be performed in a short time. Further, even when an abnormality such as contact occurs in the stator coil when the coil is mounted or when the coil end is formed, the abnormality can be detected.

  Since the partial discharge detection device 12 is configured to detect the generation of the electromagnetic wave accompanying the generation of the partial discharge using the gigahertz band electromagnetic wave antenna 12a, the partial discharge detection device 12 is less susceptible to the influence of surrounding noise, and the generation of the partial discharge It can be detected with high accuracy and high sensitivity.

Since the shared voltage between the unit coils is equalized as much as possible, the possibility of damage to the stator coil by the impulse discharge test can be reduced.
By performing the impulse discharge test described above in the manufacturing process, it is possible to manufacture a high-quality permanent magnet motor that maintains the electrical insulation between the unit coils and is damaged by the inverter surge voltage during actual operation. The fear can be reduced.

(Second Embodiment)
Hereinafter, a test method according to a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is different from the first embodiment in that the magnitude of the impulse voltage is set according to the humidity of the test environment. In addition, since the structure of the test apparatus and permanent magnet motor in 2nd Embodiment is as substantially the same as the structure of 1st Embodiment, description is abbreviate | omitted.

  FIG. 7 is a diagram showing measurement results obtained by measuring in advance the relationship between the discharge start voltage in the healthy coil and the humidity of the test environment (where the test apparatus is installed). In the first embodiment described above, the discharge start voltage for detecting an insulation abnormality between unit coils is set to Vc. However, as shown in FIG. 7, since the discharge start voltage gradually decreases as the humidity of the test environment increases, if the discharge start voltage is fixed to a constant value, depending on the humidity of the test environment, However, partial discharge may occur. In other words, when the magnitude of the impulse voltage is fixed to a constant value, it may be difficult to correctly detect an insulation abnormality between unit coils when the humidity of the test environment changes.

  Therefore, in the present embodiment, the humidity in the test environment is measured before starting the impulse discharge test, and the magnitude of the impulse voltage is detected based on the humidity to an appropriate value (occurrence of partial discharge between unit coils). Is set to the minimum necessary size). When the humidity of the test environment is about 20%, the impulse voltage applying device determines the magnitude of the impulse voltage as a voltage that does not generate a partial discharge in a healthy coil and can detect a partial discharge between unit coils ( For example, it is set to Vc) exemplified in the first embodiment. Alternatively, when the humidity of the test environment is about 95%, the magnitude of the impulse voltage is set to a value lower than the magnitude of the impulse voltage set when the humidity is 20%. Note that the method of setting the magnitude of the impulse voltage may be such that, for example, the humidity of the test environment measured by a humidity sensor or the like is input by an operator to the impulse voltage application device, and the humidity is applied to the impulse voltage application device. It may be set automatically by incorporating a sensor or the like.

  By the way, the test environment is not always maintained at a constant humidity, and the humidity may increase or decrease depending on the weather or the like. 8 and 9 are diagrams showing the results of a preliminary test for verifying the relationship between the discharge start voltage and the change in humidity. FIGS. 8A and 8B are diagrams showing changes in the discharge start voltage when the humidity is increased from 40% to 95%. FIG. 8A is a time change in humidity, and FIG. 8B is a time change in discharge start voltage when the humidity is increased. It is. FIG. 9 is a diagram showing a change in the discharge start voltage when the humidity is lowered from 95% to 40%, where (A) shows the time change of the humidity, and (B) shows the discharge start voltage when the humidity is lowered. It is time change.

  In the preliminary test when the humidity rises as shown in FIG. 8, the humidity reaches 95% when about 10 minutes have passed since the start of verification. On the other hand, the discharge start voltage gradually decreases as the humidity increases, and is approximately converged after about 30 minutes. In other words, when the humidity of the test environment increases, the discharge start voltage is approximately 20 minutes after the time when the humidity is stabilized (10 minutes after the start of verification) (about 30 minutes after the start of verification). It can be seen that the value approaches a constant value at the time).

  On the other hand, in the preliminary test when the humidity decreases as shown in FIG. 9, the humidity is 40% when about 30 minutes have passed since the start of verification. At this time, the discharge start voltage gradually increases as the humidity decreases, but there are many variations and almost converges after about 120 minutes. That is, when the humidity of the test environment increases, the discharge start voltage is approximately 90 minutes after the start of the verification (about 120 minutes after the start of verification) after about 90 minutes have passed since the time when the humidity became stable (at the time 30 minutes after the start of verification). At the point of time) is approaching a constant value.

  From these verification results, it is understood that when the humidity in the test environment changes, it takes about 30 minutes to 2 hours for the discharge start voltage to converge. That is, in the impulse discharge test, not only when the test is performed (immediately before the application of the impulse voltage is started) but also in accordance with the humidity in the test environment from a predetermined period before the test is started (appropriate value of the impulse voltage). Change). Therefore, in the present embodiment, the magnitude of the impulse voltage is set based on the maximum value of the measured humidity by measuring the change in humidity from two hours before the start of the impulse discharge test. For example, in the case where the humidity at the time of the test is 60% and the humidity was 95% 30 minutes before that, the magnitude of the impulse voltage is based on the highest value (95%) of the observed humidity. Thus, an appropriate value is set from the correlation diagram as shown in FIG.

  Thus, in 2nd Embodiment, after setting the magnitude | size of an impulse voltage in said procedure, the impulse discharge test is implemented. Thereby, it becomes possible to carry out an impulse discharge test with a more appropriate voltage value, and it is possible to verify an insulation abnormality of the stator coil as in the first embodiment.

  In particular, in the second embodiment, the change in humidity of the test environment is measured, and the magnitude of the impulse voltage is set based on the maximum value of the measured humidity. The possibility of erroneous detection when there is an abnormality in insulation can be reduced. In addition, since the humidity is measured during a predetermined period before the impulse test is started, the impulse voltage can be set appropriately even when the humidity of the test environment changes, and the detection error of insulation abnormality can be improved. Can be improved. Further, by setting the impulse voltage to an appropriate value, a voltage higher than necessary is not applied, so that damage to the stator coil during the impulse discharge test is reduced, and the possibility of damage to the stator coil is reduced. be able to.

(Third embodiment)
Hereinafter, a test method according to a third embodiment of the present invention will be described with reference to FIGS. The third embodiment is different from the first embodiment in that a high-frequency current probe is used as a partial discharge detection device instead of an electromagnetic wave antenna. In addition, the same code | symbol is attached | subjected to the component substantially the same as 1st Embodiment, and description is abbreviate | omitted. The configuration of the permanent magnet motor is the same as that of the first embodiment.

  FIG. 10 is a block diagram showing the configuration of the test apparatus 20 according to the third embodiment of the present invention. The partial discharge detector 21 used for the impulse discharge test includes a high-frequency current probe 21a, a bandpass filter 21b, and a discharge detector 21c. Among them, the high-frequency current probe 21 a is provided so as to detect a current flowing through the voltage application line 11 a of the impulse voltage applied from the impulse voltage application device 11 to the stator coil.

  The current detected by the high-frequency current probe 21a during the test includes a current accompanying application of an impulse voltage and a high-frequency current accompanying the occurrence of partial discharge. Of these currents, the band-pass filter 21b passes only the current component signal caused by the high-frequency current accompanying the occurrence of the partial discharge. Thereby, the discharge detector 21c can detect the presence or absence of the occurrence of the partial discharge based on the current component signal accompanying the occurrence of the partial discharge.

  By the way, in the impulse test, a high voltage is applied to the stator coil. At this time, if the amount of energy applied to the stator coil is large, there is a risk of damage such as damage to a healthy stator coil. In this case, in order to reduce damage to the stator coil, the fall time of the impulse voltage (negative pulse voltage in the present embodiment), that is, the peak voltage (negative maximum value) after the voltage application is started. For example, the time required to reach () may be 1 microsecond or less. On the other hand, if the fall time of the impulse voltage is set to a very short time (for example, several nanoseconds), it becomes difficult to separate the current generated by applying the impulse voltage from the high-frequency current generated by partial discharge. Discharge detection accuracy will be reduced.

  In this case, by setting the fall time of the impulse voltage to, for example, several tens to several hundreds of nanoseconds, the risk that the amount of energy is reduced and damages the stator coil is reduced, and partial discharge is generated. It is possible to separate the resulting current component. Therefore, in the configuration of the stator coil according to the present embodiment, the fall time is set to about 120 nanoseconds, and both reliable detection of partial discharge and reduction of damage are achieved. Although the fall time depends on the performance of the partial discharge detection device 21 or the like, if the fall time is approximately in the range of 100 to 150 nanoseconds, the above-described effects can be achieved at the same time.

  FIG. 11 is a diagram showing a current waveform detected in the impulse discharge test. FIG. 11A shows a current measurement result of a healthy coil in which insulation between unit coils is normally performed and no contact is made between unit coils. (B) shows the current measurement result of the stator coil having contact between the unit coils, for example, when the U-phase coil 3 has a dummy wedge between the first unit coil 3a1 and the second unit coil 3a2. ing. In the case of a healthy coil in which insulation between unit coils is maintained, even when an impulse voltage is applied, a high-frequency current is not detected as shown in FIG. On the other hand, in the case of a stator coil having an insulation abnormality between unit coils, when an impulse voltage is applied, a current waveform of a high-frequency current is observed with the occurrence of partial discharge as shown in FIG.

  As described above, the partial discharge detection device 21 that detects the high-frequency current accompanying the occurrence of the partial discharge can also detect the insulation abnormality in the stator coil such as the insulation paper between the unit coils or the missing dummy wedge. The same effects as those of the first embodiment can be obtained.

  In particular, in the third embodiment, by setting the fall time of the impulse voltage to about 120 nanoseconds, it is possible to detect an insulation abnormality and reduce the possibility of damaging the stator coil. It becomes. As a result, when the insulation state of the first unit coil and the second unit coil having a large surge sharing voltage during actual operation is verified, the peak voltage can be set larger, and the settable range of the peak voltage is expanded. Yes. Therefore, it is possible to easily set the impulse voltage to the minimum necessary level capable of detecting the occurrence of partial discharge.

(Fourth embodiment)
Hereinafter, a test method according to a fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment is different from the first embodiment in that the impulse discharge test is performed while changing the magnitude of the impulse voltage in a stepwise manner from a low voltage to a high voltage. In addition, since the structure of the test apparatus and permanent magnet motor in 4th Embodiment is as substantially the same as the structure of 1st Embodiment, description is abbreviate | omitted.

  In the fourth embodiment, a plurality of, for example, four unit coils are connected in series, and a healthy product coil in which the insulation state between the unit coils is normal, and between the unit coils constituting the stator coil. A plurality of test coils in which an abnormality in the insulation state is simulated in one place or a plurality of places are produced, and a discharge start voltage in each test coil is produced using the same impulse voltage generator as in the first embodiment. Preliminary tests to measure are performed. In this preliminary test, the magnitude of the impulse voltage was changed stepwise from a low voltage (for example, 1 kV) to a high voltage (for example, 20 kV) with a predetermined width (for example, in increments of 1 kV) and applied to the stator coil, and partial discharge occurred. Sometimes the amount of charge released from the stator coil is measured by a known charge amount measuring device, and the relationship between the amount of charge and the applied voltage (peak value of impulse voltage) is verified.

  FIG. 12 is a diagram illustrating a result of a preliminary test performed on a test coil in which an insulation abnormality has occurred between, for example, the first unit coil and the second unit coil. The discharge charge amount on the vertical axis indicates the charge amount detected by the charge amount measuring device, and the applied voltage on the horizontal axis indicates the magnitude of the impulse voltage. In addition, the discharge occurrence threshold is a threshold for the amount of charge that is considered to be a partial discharge. FIG. 12 shows that the magnitude of the applied voltage is about 14 kV and the amount of discharge charge exceeds a predetermined discharge occurrence threshold, that is, the discharge start voltage at which partial discharge has occurred is about 14 kV. In this preliminary experiment, a plurality of test coils with different types and numbers of insulation abnormal sites were produced, and the discharge start voltage was measured for each. The discharge occurrence threshold is set to a value measured in advance by a preliminary test in accordance with the specifications of the stator coil (number of turns, wire thickness, etc.).

  In the impulse discharge test, the insulation abnormality between unit coils is verified by comparing the voltage at the time of partial discharge with the discharge start voltage in the preliminary test. In addition, when a partial discharge is detected (when an insulation abnormality occurs), by comparing with the discharge start voltage of each test coil obtained in the preliminary test, there is an insulation abnormality in any part of the stator coil. It is estimated whether it has occurred.

  In this way, verifying whether or not the insulation state between unit coils is normal by comparing the voltage at which partial discharge has occurred and the result of prior verification (discharge start voltage of each test coil in the preliminary test). For example, the same effects as those of the first embodiment can be obtained. In particular, in the fourth embodiment, since the impulse discharge test is repeatedly performed while changing the magnitude of the impulse voltage within a predetermined range, not only the presence / absence of the insulation abnormality can be detected, but also the part where the insulation abnormality occurs is detected. can do.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the gist thereof. For example, the present invention can be modified or expanded as follows.

  In the first embodiment, an impulse test was performed by applying a positive (single polarity of positive voltage) impulse voltage, and in the third embodiment, a negative (single polarity of negative voltage) impulse voltage was applied. Is not limited to each embodiment. For example, an impulse voltage having both polarities (a voltage across a positive voltage and a negative voltage) may be applied, or both unipolar positive and bipolar impulse voltages may be applied. In that case, by setting the rise time or fall time of the impulse voltage to 100 nanoseconds to 150 nanoseconds, partial discharge can be generated and damage to the stator coil due to the impulse discharge test can be reduced.

In step 5 of the first embodiment, only some of the five types of tests shown in FIG. 1 may be performed, or other tests may be added.
In the second embodiment, the humidity of the test environment is measured. This test environment is not limited to the place where the test device such as the impulse voltage application device or the partial discharge detection device is installed, but the stator is transported in the production line. Routes may be included. As a result, even if the test equipment is installed with air conditioning equipment, the magnitude of the impulse voltage is appropriately adjusted even when the stator is exposed to various humidity environments during transportation on the production line. Can be set.

  Further, the period used for calculating the discharge start voltage may be determined according to the change state of the humidity of the test environment (whether the humidity is increasing or decreasing). As a result, the test time can be shortened.

  You may comprise a test device with both an electromagnetic wave antenna and a high frequency current probe. That is, in the impulse discharge test, the detection of the electromagnetic wave accompanying the generation of the partial discharge using the electromagnetic wave antenna having sensitivity in the gigahertz band and the high frequency current generated by the generation of the partial discharge using the high frequency current probe provided in the voltage application line. Detection may be performed. Thereby, generation | occurrence | production of the partial discharge accompanying application of an impulse voltage can be detected with a sufficient precision, and the reliability of a permanent magnet electric motor can be improved more by extension.

  In the impulse discharge test, a plurality of test methods described above may be combined. For example, the test method for applying a predetermined impulse voltage according to the first embodiment may be combined with the test method for applying the impulse voltage according to the fourth embodiment while gradually increasing the impulse voltage from a low voltage to a high voltage. Moreover, you may implement combining the test method which sets the magnitude | size of an impulse voltage based on the humidity of 2nd Embodiment, and the test method by the high frequency current probe of 3rd Embodiment. Alternatively, all of these test methods may be combined. For example, in the fourth embodiment, the preliminary test may be performed at different humidity, and the result of the preliminary test to be compared may be selected according to the humidity during the impulse discharge test.

  Specific numerical values such as the specific configuration (the number of unit coils, the number of parallel circuits, the connection method, etc.), the magnitude of the impulse voltage, and the predetermined width of the fourth embodiment in each embodiment are examples. It was just These are pre-tested according to the circuit configuration of the stator coil, the material, thickness, number of turns, insulation strength of the insulation coating, etc., to match the required specifications of the permanent magnet motor to be manufactured. May be set as appropriate.

  Although an example of application to an inverter-driven three-phase permanent magnet type motor has been shown, the number of phases and driving method are not limited to this, and for example, an outer rotor type electric motor, an induction motor, or a generator, etc. Can be applied to.

  In the drawings, 1 is a stator, 2 is a stator core (iron core), 3, 4 and 5 are stator coils, 3a, 3b, 4a, 4b, 5a and 5b are unit coils, 6 is interphase insulating paper, and 7, 8 and 9 are Power terminals 10, 10 and 20 are test devices, 11 is an impulse voltage application device, 12 and 21 are partial discharge detection devices, 12a is an electromagnetic wave antenna, 12b and 21c are discharge detectors, 21a is a high-frequency current probe, and 21b is a bandpass filter. , Na and Nb indicate the neutral point (neutral point) of each phase.

Claims (12)

A test for verifying the insulation state between the unit coils of the stator coil in the manufacturing process of a rotating electrical machine configured by winding a plurality of stator coils in which a plurality of unit coils are connected in series to an iron core A method,
After the stator coils of the plurality of phases are mounted on the iron core and the stator coils of the respective phases are connected to form a neutral point, between the neutral point and the power supply terminals of the stator coils of the plurality of phases. An impulse discharge test is performed in which a partial discharge detection device detects the presence or absence of partial discharge between the unit coils for each of the plurality of phase stator coils by applying an impulse voltage by an impulse voltage application device. Test method for rotating electrical machines.   In the impulse discharge test, the impulse voltage applied to the stator coil is measured in advance by measuring the divided voltage of each unit coil during the operation of the rotating electrical machine, and the partial discharge occurs when contact occurs between the unit coils at the shared voltage. 2. The rotating electrical machine according to claim 1, wherein a portion where the occurrence of the partial discharge is confirmed is confirmed, and the size is set to a minimum necessary size capable of detecting the occurrence of partial discharge in the portion. Test method.   The impulse voltage applied to the stator coil in the impulse discharge test is the first unit coil provided closest to the power supply terminal among the plurality of unit coils constituting the multi-phase stator coil, and 3. The minimum required size capable of detecting the occurrence of partial discharge with a second unit coil provided adjacent to the first unit coil. Test method for rotating electrical machines.   In the impulse discharge test, the relationship between the impulse voltage at which partial discharge is started and humidity is measured in advance, the humidity of the test environment in a predetermined period before the impulse discharge test is started, and the predetermined period 4. The test method for a rotating electrical machine according to claim 1, wherein a magnitude of an impulse voltage applied to the stator coil is set based on a maximum value of humidity measured in step 1.   In the impulse discharge test, the predetermined period is set to 2 hours, and the magnitude of the impulse voltage applied to the stator coil is set based on a maximum value of humidity measured during the period. Item 5. A test method for a rotating electrical machine according to Item 4.   2. The impulse voltage applied to the stator coil in the impulse test has a time required to reach a peak voltage from the start of application within a range of 100 nanoseconds to 150 nanoseconds. The test method of the rotating electrical machine according to any one of claims 1 to 5.   7. The partial discharge detection device according to claim 1, wherein the partial discharge detection device is configured to detect generation of electromagnetic waves accompanying generation of partial discharge using an electromagnetic wave antenna capable of detecting electromagnetic waves in a gigahertz band. A test method for a rotating electrical machine according to any one of the preceding claims.   The partial discharge detection device detects a high-frequency current flowing in the voltage application line when a partial discharge occurs by using a high-frequency current probe provided in a voltage application line of an impulse voltage applied from the impulse voltage application device to the stator coil. The test method for a rotating electrical machine according to any one of claims 1 to 6, wherein the test method is for a rotating electrical machine.   The partial discharge detection device detects the generation of electromagnetic waves accompanying the generation of partial discharge using an electromagnetic wave antenna capable of detecting electromagnetic waves in the gigahertz band, and the voltage of the impulse voltage applied to the stator coil from the impulse voltage application device. 7. The rotation according to claim 1, wherein both the detection of the high-frequency current accompanying the generation of the partial discharge using the high-frequency current probe provided in the application line is performed. Electrical testing method. A plurality of test coils in which a non-insulated state is simulated between one unit coil or a plurality of unit coils of the stator coil in advance are produced, and partial discharge is generated in the portions where the non-insulated state is generated in each of the test coils. Measure the discharge generation voltage at which
In the impulse discharge test, application is repeated while changing the magnitude of the impulse voltage with a predetermined width, and by comparing the voltage when the partial discharge occurs with the discharge generation voltage measured by the test coil, The method for testing a rotating electrical machine according to any one of claims 1 to 9, wherein a part where an abnormality occurs in the insulation state is detected.   11. The rotating electrical machine according to claim 1, wherein, in the impulse discharge test, an impulse voltage applied to the stator coil is unipolar or bipolar, or both are applied. Test method. In a method of manufacturing a rotating electrical machine configured by winding a stator coil around an iron core,
A mounting step of mounting a multi-phase stator coil on the iron core;
A neutral point connection step of electrically connecting the plurality of stator coils to form a neutral point;
Forming step of forming the multi-phase stator coil;
An electrical test process for conducting an electrical test on the stator coil,
The method for manufacturing a rotating electrical machine, wherein the impulse discharge test according to any one of claims 1 to 11 is performed in the electrical test step.

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