WO2020245859A1

WO2020245859A1 - Winding short circuit diagnosis device and winding short circuit diagnosis method

Info

Publication number: WO2020245859A1
Application number: PCT/JP2019/021901
Authority: WO
Inventors: 久栄中村
Original assignee: 株式会社トーエネック
Priority date: 2019-06-03
Filing date: 2019-06-03
Publication date: 2020-12-10
Also published as: JP7196297B2; JPWO2020245859A1

Abstract

[Problem] To easily identify a mode of short circuit in a winding in a stator or a rotor of a rotary machine in which concentrated winding has been performed on teeth. [Solution] A magnetic field generated in three-phase windings 24U, 24V, 24W wound around each of teeth 22b is measured along the extension direction of said teeth 22b at each prescribed interval d by using a magnetic field sensor 6, the orientation of the magnetic field measured by the magnetic field sensor 6 is determined by comparing the phase difference between an alternating current flowing in the three-phase windings 24U, 24V, 24W and an output voltage Vs at each measurement position t_i, and it is assessed, on the basis of a change mode of the output voltage Vs for which the orientation of the magnetic field has been taken into account, whether, in the three-phase windings 24U, 24V, 24W: a short circuit has occurred between windings adjacent in the extension direction of the teeth 22b; or, alternatively, a short circuit has occurred between layers. The mode of short circuit in the three-phase windings 24U, 24V, 24W wound around the teeth 22b is thereby easily identified.

Description

Winding short circuit diagnostic device and winding short circuit diagnostic method

The present invention is a winding short-circuit diagnostic device and a winding short-circuit diagnostic method for diagnosing a short-circuit of a winding in a stator or a rotor of a rotor in which a plurality of teeth arranged at substantially equal intervals in the circumferential direction are centrally wound. Regarding.

In Japanese Patent Application Laid-Open No. 2009-115505 (Patent Document 1), an impulse voltage is applied between the terminals of windings of any phase among the windings inside a rotating machine such as an electric motor or a generator, and the impulse is applied. The waveform of the vibration voltage generated between the terminals of the winding due to the application of voltage is detected, and the waveform of the detected vibration voltage is created in advance. The vibration voltage of the normal winding (winding without short circuit). A winding short circuit diagnostic device for diagnosing the presence or absence of a short circuit in a winding is described by comparing with the waveform of.

In the winding short-circuit diagnostic device, which phase of the winding is the short-circuit, for example, in the case of a three-phase induction motor, is the short-circuit in the U phase, or in the V phase or W phase? It is possible to identify whether it is occurring.

By the way, if it is possible to identify how the windings inside a rotating machine such as an electric motor or a generator are short-circuited, how to wind the windings by feeding back the mode information of the short-circuit to the design stage. Since it is possible to take measures for the structure of the teeth for winding the winding and the winding, it leads to a reduction in the short-circuit occurrence rate of the rotating machine such as an electric motor and a generator, which is a great merit. Here, as a mode of short-circuiting the windings, for example, a mode in which a short-circuit occurs between windings adjacent in the length direction of the teeth and a mode in which a short-circuit occurs between layers of the windings can be considered.

In addition, from the viewpoint of reducing the short-circuit occurrence rate of rotors such as electric motors and generators, the applicant also referred to Patent No. 64044424 (Patent Document 2) as a stator or rotation of a rotor in which teeth are centrally wound. We are proposing a winding short circuit diagnostic device that can identify where the short circuit occurs in the winding in the child.

JP-A-2009-115505 Japanese Patent No. 64044424

The present invention has been made in view of the above, and is a winding short-circuit diagnostic apparatus and a winding short-circuit diagnostic apparatus capable of easily specifying a mode of short-circuiting of a winding in a stator or a rotor of a rotating machine in which a tooth is centrally wound. The main purpose is to provide a winding short circuit diagnostic method.

According to a preferred embodiment of the winding short-circuit diagnostic apparatus according to the present invention, a short-circuit of a winding in a stator or a rotor of a rotor in which a plurality of teeth arranged at substantially equal intervals in the circumferential direction are centrally wound is diagnosed. A winding short circuit diagnostic device is configured. The winding short-circuit diagnostic device includes a voltage oscillator, a magnetic field sensor, a memory, and a processor. The voltage oscillator is configured to apply an AC voltage between the terminals of the winding. The magnetic field sensor measures the strength of the magnetic field generated in the winding wound for each tooth in response to the application of an AC voltage at predetermined intervals along the extending direction of the tooth. The memory stores the AC voltage or the AC current flowing through the winding due to the AC voltage and the strength of the magnetic field. The processor determines the direction of the magnetic field stored in the memory for each measurement position based on the AC voltage or AC current and the strength of the magnetic field. Further, the processor determines that no short circuit has occurred in the winding in the case of the first pattern in which all the determined magnetic field directions are the first direction, and the magnetic field direction is from the first direction to the first pattern. In the case of the second pattern, which changes from the second direction to the first direction after changing in the second direction opposite to the one direction, a short circuit occurs between the windings adjacent to the extending direction of the teeth. In the case of the third pattern in which the direction of the magnetic field changes from the first direction or the second direction to the second direction or the first direction and then changes in the second direction or the first direction, and the magnetic field. In the case of the fourth pattern in which all the directions of are the second direction, it is determined that a short circuit has occurred between the layers of the winding.

Here, the "magnetic field strength" in the present invention corresponds to the magnitude of the magnetic flux density generated in the winding wound for each tooth, or the voltage proportional to the magnitude of the magnetic flux density.

As a result of diligent research on the short circuit of the winding in the stator or rotor of the rotor in which the teeth are centrally wound, the present inventor has obtained the strength of the magnetic field at predetermined intervals along the extending direction of the teeth. It has been found that the pattern of change in the direction of the coil and the magnetic field differs depending on the mode of short circuit of the winding. Based on such research results, in the present invention, in the case of the first pattern, it is determined that a short circuit has not occurred in the winding, and in the case of the second pattern, it is adjacent to the extending direction of the teeth. Since it is determined that a short circuit has occurred between the windings, and in the case of the third pattern and the fourth pattern, it is determined that a short circuit has occurred between the layers of the windings, the mode of the short circuit of the windings can be simplified. Can be identified. As a result, the short-circuit mode information can be fed back to the design stage, and measures can be taken regarding the winding method of the winding and the structure of the teeth for winding the winding. As a result, it is possible to reduce the short-circuit occurrence rate of rotating machines such as electric motors and generators, which can contribute to quality improvement.

According to a further embodiment of the winding short circuit diagnostic apparatus according to the present invention, the processor is the case of the third pattern, in which the direction of the magnetic field from the first direction or the second direction to the second direction or the first direction. If the change occurs at the end of the teeth in the extending direction, compare the strength of the magnetic field in the second direction with the threshold, and if the strength of the magnetic field is greater than or equal to the threshold, and / or the magnetic field. The absolute value of the change rate of the magnetic field strength when the direction of is changed from the first direction or the second direction to the second direction or the first direction is compared with the reference change rate, and the absolute value of the change rate is the relevant value. If it is greater than or equal to the reference rate of change, it is determined that a short circuit has occurred between the windings adjacent to the longitudinal direction of the teeth, and if the strength of the magnetic field is less than the threshold value, and / or the absolute value of the rate of change is If it is less than the reference change rate, it is determined that a short circuit has occurred between the layers of the winding.

According to this embodiment, is the short circuit of the winding generated at the measurement start position or the measurement end position of the magnetic field at the end in the extending direction of the tooth a short circuit between the windings adjacent to the extending direction of the tooth? , It can be determined whether it is a short circuit between the winding layers. Even if there is a short circuit between windings adjacent in the extending direction of the teeth, if the windings are short-circuited at the end of the extending direction of the teeth at the measurement start position or measurement end position of the magnetic field. By comparing the strength of the magnetic field in the second direction with a preset threshold, because the direction of the magnetic field remains changing from the first direction or the second direction to the second or the first direction. / Or by comparing the absolute value of the rate of change in the strength of the magnetic field when the direction of the magnetic field changes from the first direction or the second direction to the second direction or the first direction with a preset reference rate of change. , It is determined whether the short circuit generated is a short circuit between windings adjacent to each other in the extending direction of the teeth or a short circuit between the windings. Here, under the same conditions, the short circuit between the winding layers has a weaker magnetic field strength or the magnetic field strength than the short circuit between the windings adjacent to each other in the extending direction of the teeth. Since the absolute value of the rate of change is small, the strength of the magnetic field when a short circuit occurs between the layers of the winding, or the absolute value of the rate of change of the strength of the magnetic field and the winding adjacent to the extension direction of the teeth. By setting a threshold value or a reference change rate to an appropriate value between the absolute value of the magnetic field strength when a short circuit occurs between them or the change rate of the magnetic field strength, the extension direction of the teeth. It is possible to distinguish between a short circuit between windings adjacent to the coil and a short circuit between the windings.

According to a further form of the winding short circuit diagnostic apparatus according to the present invention, the memory can store the strength of the magnetic field in association with the measurement position. Then, when the processor determines that a short circuit has occurred between the layers of the winding, it determines that the winding has a short circuit at the measurement position where the direction of the magnetic field is first in the second direction.

According to this embodiment, when a short circuit occurs between the layers of the winding, it is possible to specify where in the winding wound around the tooth the short circuit occurs. As a result, it is possible to acquire information on locations where short circuits are likely to occur. Therefore, by feeding back the information to the design stage, it is possible to take structural or strong measures at locations where short circuits are likely to occur. , It leads to the reduction of the short circuit occurrence rate of rotating machines such as electric motors and generators, and can contribute to quality improvement.

According to a further form of the winding short circuit diagnostic apparatus according to the present invention, the memory can store the strength of the magnetic field in association with the measurement position. Then, when the processor determines that a short circuit has occurred between the windings adjacent to the longitudinal direction of the teeth, the processor compares the strength of the magnetic field in the second direction with the second threshold value, and first sets the second threshold value or higher. It is determined that a short circuit has occurred in the winding at the measurement position associated with the strength of the magnetic field determined to be present.

According to this embodiment, when a short circuit occurs between windings adjacent to each other in the longitudinal direction of the teeth, it is possible to specify where in the windings wound around the teeth the short circuit occurs. .. As a result, it is possible to acquire information on locations where short circuits are likely to occur. Therefore, by feeding back the information to the design stage, it is possible to take structural or strong measures at locations where short circuits are likely to occur. , It leads to the reduction of the short circuit occurrence rate of rotating machines such as electric motors and generators, and can contribute to quality improvement.

According to a further form of the winding short circuit diagnostic apparatus according to the present invention, the voltage oscillator applies an AC voltage having a frequency higher than the commercial frequency between the terminals of the winding.

As the frequency of the AC voltage applied by the voltage oscillating unit is increased, the present inventors reduce the measured magnetic flux density due to the influence of the inductance component of the winding, while short-circuiting the winding. It was found that the rate of decrease in the magnetic flux density measured at the location where the short circuit occurs tends to be larger than the rate of decrease in the magnetic flux density measured at the location where the short circuit does not occur. That is, when the frequency of the AC voltage applied by the voltage oscillating unit is increased, the value of the magnetic flux density measured at the normal place where the short circuit does not occur in the winding and the value measured at the place where the short circuit occurs. It was found that there is a large difference between the value of the magnetic flux density and the value of the magnetic flux density. Based on these research results, in the present embodiment, since the frequency of the AC voltage applied between the terminals of the winding is set to a frequency higher than the commercial frequency, it becomes easy to identify the presence or absence of a short circuit. ..

According to a further form of the winding short circuit diagnostic apparatus according to the present invention, the voltage oscillator applies an AC voltage of 200 volts or less between the terminals of the winding.

According to this embodiment, the power supply supplied to the voltage oscillator can be miniaturized, and the electronic circuit of the voltage oscillator can be finished at low cost. As a result, the winding short circuit diagnostic apparatus itself can be downsized and the cost can be reduced.

According to a further form of the winding short circuit diagnostic apparatus according to the present invention, the magnetic field sensor has a search coil for measuring the strength of the magnetic field. When measuring the strength of the magnetic field, the magnetic field sensor is arranged so that the axial direction of the search coil is parallel to the axial direction of the winding wound on the tooth.

According to this embodiment, it is possible to accurately measure the strength of the magnetic field generated in the winding by the AC voltage applied between the terminals of the winding by the voltage oscillator.

According to a further form of the winding short circuit diagnostic apparatus according to the present invention, the magnetic field sensor has a search coil for measuring the strength of the magnetic field. Then, when the magnetic field sensor measures the strength of the magnetic field, the axis of the search coil on the virtual projection plane when viewed from one side in the axial direction of the stator or rotor is wound around the teeth. It is arranged so as to overlap the axis of.

According to this embodiment, since the magnetic field strength is measured in a state where the axis of the search coil of the magnetic field sensor is aligned with the axis of the winding wound around the tooth, the side of the winding wound around the tooth is measured. The influence of the magnetic field generated by the edge, in other words, the portion of the winding wound around the tooth that is radially outwardly separated from the axis can be suppressed. This makes it possible to more accurately diagnose the presence or absence of a short circuit in the winding.

According to a preferred embodiment of the winding short-circuit diagnostic method according to the present invention, a short-circuit of the winding in a stator or a rotor of a rotor in which a plurality of teeth arranged at substantially equal intervals in the circumferential direction are centrally wound. A winding short circuit diagnostic method for diagnosis is configured. In the winding short circuit diagnosis method, (a) an AC voltage is applied between the terminals of the winding wound for each tooth, and (b) a magnetic field generated in the winding wound for each tooth in response to the application of the AC voltage. The strength of is measured at predetermined intervals along the extension direction of the teeth, and (c) the AC voltage or the AC current flowing through the winding due to the AC voltage and the measured magnetic field strength are measured. Stored, (d) the direction of the stored magnetic field at predetermined intervals is determined based on (d) the AC voltage or AC current, and the strength of the magnetic field, and (e) all the determined magnetic field directions are the first directions. In the case of the first pattern, it is determined that no short circuit has occurred in the winding, and the direction of the magnetic field stored in the memory changes from the first direction to the second direction opposite to the first direction. In the case of the second pattern that changes from the second direction to the first direction after the change, it is determined that a short circuit has occurred between the windings adjacent to the extending direction of the teeth, and the magnetic field stored in the memory. In the case of the third pattern in which the direction of is changed from the first direction or the second direction to the second direction or the first direction and then changes in the second direction or the first direction, and all the directions of the magnetic field are the first. In the case of the fourth pattern having two directions, it is determined that a short circuit has occurred between the layers of the winding.

According to a further embodiment of the winding short circuit diagnostic method according to the present invention, the step (e) is the case of the third pattern, and the magnetic field from the first direction or the second direction to the second direction or the first direction. If the change in direction occurs at the end of the teeth in the extending direction, the strength of the magnetic field in the second direction is compared with the threshold value, and if the strength of the magnetic field is greater than or equal to the threshold value, and / Alternatively, the absolute value of the change rate of the magnetic field strength when the direction of the magnetic field changes from the first direction or the second direction to the second direction or the first direction is compared with the reference change rate, and the absolute value of the change rate is absolute. If the value is greater than or equal to the reference rate of change, it is determined that a short circuit has occurred between the windings adjacent to the longitudinal direction of the teeth, and if the strength of the magnetic field is less than the threshold value, and / or the rate of change. If the absolute value is less than the reference rate of change, it includes a step of determining that a short circuit has occurred between the layers of the winding.

According to the present invention, it is possible to specify the mode of short-circuiting of the winding in the stator or rotor of the rotating machine in which the teeth are centrally wound.

It is a block diagram which shows the outline of the structure of the winding short circuit diagnostic apparatus 1 which concerns on embodiment of this invention. It is explanatory drawing which shows the state which looked at the electric motor 2 in the state which the rotor 32 was removed from one side in the axial direction. It is explanatory drawing which shows the outline of the structure of the stator 22. It is a perspective explanatory view which shows the positional relationship between the U-phase winding 24U and the search coil 62 installed on the U-phase winding 24U. It is explanatory drawing which shows the state which looked at the positional relationship between the U-phase winding 24U and the search coil 62 installed on the U-phase winding 24U in the cross section cut by the plane orthogonal to the axes CL1 and CL2. It is explanatory drawing which shows the state at the time of measuring the magnetic field while moving the search coil 62 installed on the U-phase winding 24U at a predetermined interval d along the extending direction of a tooth 22b. It is explanatory drawing which shows typically the state of the magnetic field generated around the U-phase winding 24U when an AC voltage is applied between the terminals of the U-phase winding 24U. It is explanatory drawing which shows typically the state of the magnetic field generated around the U-phase winding 24U when the short circuit S occurs in a part of the U-phase winding 24U. It is explanatory drawing which shows the state of the alternating current and the output voltage Vs when the phase difference is within a predetermined range. It is explanatory drawing which shows the state of the alternating current and the output voltage Vs when the phase difference is out of a predetermined range. It is an experimental result which shows the measurement result of the output voltage Vs in the solenoid coil SLC1. It is an experimental result which shows the measurement result of the output voltage Vs in a solenoid coil SLC2. It is an experimental result which shows the measurement result of the output voltage Vs in a solenoid coil SLC3. It is an experimental result which shows the measurement result of the output voltage Vs in a solenoid coil SLC4. It is an experimental result which shows the measurement result of the output voltage Vs in a solenoid coil SLC5. It is an experimental result which shows the measurement result of the output voltage Vs in a solenoid coil SLC6. It is an experimental result which shows the measurement result of the output voltage Vs in a solenoid coil SLC7. It is an experimental result which shows the measurement result of the output voltage Vs in a solenoid coil SLC8. It is explanatory drawing which shows typically the solenoid coil SLC1. It is explanatory drawing which shows typically the solenoid coil SLC2. It is explanatory drawing which shows typically the solenoid coil SLC3. It is explanatory drawing which shows typically the solenoid coil SLC4. It is explanatory drawing which shows typically the solenoid coil SLC5. It is explanatory drawing which shows typically the solenoid coil SLC6. It is explanatory drawing which shows typically the solenoid coil SLC7. It is explanatory drawing which shows typically the solenoid coil SLC8. It is explanatory drawing which shows the state when the output voltage Vs is measured using the magnetic field sensor 106 of the modification.

Next, the best mode for carrying out the present invention will be described with reference to examples.

As shown in FIG. 1, the winding short circuit diagnostic apparatus 1 according to the embodiment of the present invention is any one of the three-

phase windings

24U, 24V, and 24W described later of the electric motor 2 as a rotating machine (see FIG. 2). A voltage oscillating unit 4 that applies an AC voltage between the terminals, a magnetic field sensor 6 that measures the magnetic field generated in the three-

phase windings

24U, 24V, and 24W due to the application of an AC voltage by the voltage oscillating unit 4, and a voltage. An A / D conversion unit 8 electrically connected to the oscillation unit 4 and the magnetic field sensor 6 by signal lines L1 and L2, and a diagnostic unit 10 electrically connected to the A / D conversion unit 8 by signal lines L3. The diagnostic unit 10 is provided with a display device 12 electrically connected by a signal line L4.

The electric motor 2 is configured as a general-purpose three-phase induction motor, and mainly includes a stator 22 and a rotor 32 as shown in FIG.

The stator 22 is formed by laminating thin electromagnetic steel sheets (ferromagnetic materials), and as shown in FIG. 3, the stator 22a is formed in a substantially annular shape, and the yoke 22a is formed from the inner peripheral surface of the yoke 22a. It is equipped with a plurality of teeth 22b extending toward the center of the surface.

Eighteen teeth 22b are provided on the inner peripheral surface of the yoke 22a at equal intervals in the circumferential direction, for example. As shown in FIG. 2, each tooth 22b is directly provided with three-

phase windings

24U, 24V, 24W via an insulator (not shown) (so-called centralized winding method). That is, the U-phase winding 24U is wound around 6 of the 18 teeth 22b, the V-phase winding 24V is wound around the other 6 pieces, and the W-phase winding 24W is wound around the remaining 6 pieces. There is. The ends of the three-

phase windings

24U, 24V, and 24W form a connection terminal 26 that is drawn out as a lead wire to the outside of the motor 2 and connected to a commercial AC power supply. Here, the stator 22 having the teeth 22b in which the three-

phase windings

24U, 24V, and 24W are wound by the centralized winding method is described in the present invention as "concentrated winding is performed on the teeth arranged at substantially equal intervals in the circumferential direction. This is an example of an implementation configuration corresponding to the "stator of the rotating machine".

The voltage oscillator 4 includes between the U-phase winding 24U and the V-phase winding 24V (hereinafter referred to as “UV-phase”) or the V-phase winding 24V and W among the three-

phase windings

24U, 24V, 24W. An AC voltage can be applied between the phase windings 24W (hereinafter referred to as "VW phase") or between the W phase winding 24W and the U phase winding 24U (hereinafter referred to as "WU phase"). It is configured as a function generator that can change the frequency of the applied AC voltage. As shown in FIG. 1, the AC voltage applied to each of the UV phase, the VW phase, and the WU phase by the voltage oscillator 4 or the AC current ACI flowing by the AC voltage is A / D converted. After being digitized by the unit 8, it is transmitted to the diagnostic unit 10 via the signal line L3.

In the present embodiment, the AC voltage applied by the voltage oscillating unit 4 to each of the UV phase, the VW phase, and the WW phase is 200 volts or less, and the frequency is 60 Hz (or the frequency of the commercial AC voltage oscillating unit). It was set to 1 kHz, which is higher than 200 Hz). For example, by setting the AC voltage to 50 volts or less, the power supply can be miniaturized and the electronic circuit of the voltage oscillator 4 can be finished at low cost. As a result, the winding short circuit diagnostic apparatus 1 itself can be downsized and the cost can be reduced. Further, by setting the frequency to 1 kHz, which is higher than the frequency of 60 Hz (or 50 Hz) of the commercial AC power supply, it becomes easy to identify that a short circuit has occurred in the three-

phase windings

24U, 24V, 24W. Details of the reason will be described later.

As shown in FIG. 1, the magnetic field sensor 6 includes a search coil 62 and an amplifier 64 that amplifies the magnitude of the output voltage Vs output from the search coil 62. The search coil 62 has a configuration in which the coil is wound for several turns to several tens of turns, thereby outputting an output voltage Vs proportional to the magnitude of the magnetic flux density. The output voltage Vs, which is an analog signal output from the search coil 62 and amplified by the amplifier 64, is digitized by the A / D converter 8 and then transmitted to the diagnostic unit 10 via the signal line L3.

The diagnostic unit 10 is configured as a microprocessor centered on a CPU 70 (not shown), and is connected to a ROM 72 (not shown) that stores a processing program in addition to the CPU 70, a RAM 74 that temporarily stores data, and a signal line L3. It is provided with an input port and an output port to which the signal line L4 is connected. The output voltage Vs, AC voltage, and AC current ACI from the A / D conversion unit 8 are input to the diagnosis unit 10, and the short-circuit diagnosis results of the three-

phase windings

24U, 24V, and 24W are input from the diagnosis unit 10. Is output to the display device 12 via the signal line L4.

Next, the operation at the time of short-circuit diagnosis of the three-

phase windings

24U, 24V, 24W of the electric motor 2 by the winding short-circuit diagnostic device 1 according to the embodiment of the present invention configured in this way will be described. Here, the short-circuit diagnosis of the three-

phase windings

24U, 24V, and 24W is performed with the rotor 32 removed from the motor 2, that is, with only the centralized stator 22 (see FIG. 2). The diagnosis is performed for each tooth 22b in which any one of the three-

phase windings

24U, 24V, and 24W is wound, but in the following, for convenience of explanation, the U phase wound in any one tooth 22b. A case of diagnosing a short circuit in the winding 24U will be described as an example.

First, as shown in FIG. 2, in the stator 22 in a state where the rotor 32 is removed from the electric motor 2, the magnetic field sensor 6 is installed on any one tooth 22b around which the U-phase winding 24U is wound. Here, as shown in FIGS. 2, 4 and 5, the magnetic field sensor 6 has the axis CL1 of the search coil 62 on the axis CL2 of the U-phase winding 24U wound around the teeth 22b (the axis CL2 of the teeth 22b). In parallel with each other, the distance from the surface of the U-phase winding 24U of the axis CL1 is set to a predetermined distance h (for example, 5 mm) (see FIG. 5), and the motor 2 (stator 22, When viewed from one side of the rotor 32) in the axial direction (when FIG. 2 is viewed from the direction perpendicular to the paper surface), the axial line CL1 and the axis CL2 are in an overlapping positional relationship (see FIG. 2). Will be installed. At this time, as shown in FIG. 6, the magnetic field sensor 6 is measured on the U-phase winding 24U in which the search coil 62 is wound around the root portion of the teeth 22b (the end portion of the teeth 22b connected to the yoke 22a). It is installed so that it comes to position t ₀ .

Then, in the installed state, an AC voltage (200 V or less) having a frequency of 1 kHz is applied between the terminals of the voltage oscillating unit 4 and the U-phase winding 24U, more specifically, between the U-V phase (or between the W-U phase). Then, an alternating current ACI is passed. Here, the AC current ACI flowing through the U-phase winding 24U due to the AC voltage is digitized by the A / D conversion unit 8 and then linked to the measured measurement position t ₀ and linked to the RAM 74 of the diagnosis unit 10. Is temporarily stored in.

When an AC voltage is applied between the terminals of the U-phase winding 24U (between the U-V phase or between the WW phase), a magnetic field is generated around the U-phase winding 24U. As a result, the strength of the magnetic field is output from the search coil 62 as an output voltage Vs proportional to the magnitude of the magnetic flux density. The output voltage Vs output from the search coil 62 is amplified by the amplifier 64, digitized by the A / D converter 8, and then linked to the measurement position t ₀ where the output voltage Vs is measured, and is associated with the diagnostic unit. It is temporarily stored in the RAM 74 of 10. The RAM 74 that stores the AC current ACI flowing through the U-phase winding 24U due to the AC voltage and the output voltage Vs in association with the measured measurement position t ₀ is an example of an embodiment configuration corresponding to the “memory” in the present invention. Is.

Here, when an AC voltage is applied between the terminals of the U-phase winding 24U when the U-phase winding 24U is not short-circuited, that is, when the U-phase winding 24U is in a normal state, the solid line in FIG. as shown by the arrow, the U-phase winding 24U flows alternating current ACI, the magnetic field strength _{H 0} is generated in the peripheral U-phase winding 24U by the alternating current ACI. However, when a short circuit S occurs in a part of the U-phase winding 24U, a new closed loop 24Us is generated in the U-phase winding 24U due to the short circuit S, as shown in FIG. Since the resistance becomes almost 0 in the short circuit S, the alternating current ACI flows through the short circuit S and does not flow in the closed loop 24Us.

On the other hand, the closed loop 24Us is induced electromotive force is generated by the magnetic field generated around the U-phase winding 24U by an alternating current ACI is passed, a current flows I _S due to the induced electromotive force (see FIG. 8 ). Thus, in the peripheral closed loop 24US, as shown in FIG. 8, a strength H _S by the current I _S, the direction of the magnetic field generated around the U-phase winding 24U by an alternating current ACI reverse A magnetic field is generated. That is, the output voltage is output from the search coil 62 Vs is strong magnetic field generated around the U-phase winding 24U by an alternating current ACI of _{H 0} and the current _{I S} magnetic field intensity _{H S} generated around the closed loop 24Us by The size is proportional to the difference between.

Since the induced electromotive force can be expressed as a function of the frequency of the AC voltage applied between the terminals of the U-phase winding 24U, the frequency of the AC voltage applied between the terminals of the U-phase winding 24U should be increased. Accordingly, it is possible to increase intentionally the strength H _S of the magnetic field generated around the closed loop 24US. This makes it easy to identify whether or not a short circuit has occurred in the U-phase winding 24U.

In other words, as the frequency of the AC voltage applied between the terminals of the U-phase winding 24U is increased, the measured magnetic flux density becomes smaller due to the influence of the inductance component of the U-phase winding 24U. Since the rate of decrease in the magnetic flux density measured at the location where the short circuit S occurs tends to be larger than the rate of decrease in the magnetic flux density measured at the location where the short circuit S does not occur, the U phase As the frequency of the AC voltage applied between the terminals of the winding 24U is increased, the value of the magnetic flux density measured at the location where the short circuit S occurs and the normal location where the short circuit S does not occur. It is possible to make a large difference between the value of the magnetic flux density measured in 1 and the value of the magnetic flux density, which makes it easy to identify whether or not a short circuit has occurred in the U-phase winding 24U.

Here, in FIG. 8, a short circuit occurs between the windings in which the U-phase winding 24U is adjacent to the axis CL2 direction of the U-phase winding 24U (the axis CL2 direction of the teeth 22b or the extension direction of the teeth 22b). However, even if a short circuit occurs between the layers of the U-phase winding 24U, a new closed loop is generated in the U-phase winding 24U due to the short circuit S, which is caused by the closed loop. An induced electromotive force is generated, and an alternating current ACI generates a magnetic field in the direction opposite to the direction of the magnetic field generated around the U-phase winding 24U.

In addition, when a short circuit occurs between windings adjacent to the axis CL2 direction of the U-phase winding 24U (the axis CL2 direction of the teeth 22b or the extending direction of the teeth 22b), the U-phase winding 24U than when a short circuit occurs in the layers of the winding, the value of the current I _S flowing through the closed loop 24Us also increases (following formulas (1) and (2) refer). Therefore, when a short circuit occurs between the windings adjacent to the axis CL2 direction of the U-phase winding 24U (the axis CL2 direction of the teeth 22b or the extending direction of the teeth 22b), the U-phase winding 24U than when a short circuit occurs in the layers of windings, the absolute value of the strength H _S and the rate of change of the magnetic field of the magnetic field generated around the closed loop 24Us increases.

(Number 1)
Is = 1 / √ (R ² + n ² , ω ² , L ² ), dφ / dt ... (1)
Is = 1 / √ (R ² + N ² , ω ² , L ² ), dφ / dt ... (2)

Here, the equation (1) is a current Is when a short circuit occurs between windings adjacent to the axis CL2 direction of the U-phase winding 24U (the axis CL2 direction of the teeth 22b or the extending direction of the teeth 22b). The formula (2) is a formula for obtaining the current Is when a short circuit occurs between the U-phase windings 24U between the windings, and N> n. R is the resistance of the short-circuit S portion, ω is the angular frequency, L is the inductance component of the short-circuit S portion, φ is the magnetic flux passing through the short-circuit S portion, t is the time, and n and N are the short-circuit S. The number of turns.

When the output voltage Vs is temporarily stored in the RAM 74 together with the measurement position t ₀ , the CPU 70 of the diagnostic unit 10 subsequently determines the magnetic field sensor 6 (based on the relationship between the AC current ACI stored in the RAM 74 and the output voltage Vs. The direction of the magnetic field measured by the search coil 62) is determined. Specifically, the phase difference between the AC current ACI and the output voltage Vs is compared, and the direction of the magnetic field is determined based on the phase difference. As shown in FIG. 9, if the phase difference between the AC current ACI and the output voltage Vs is within a predetermined range, it is determined that the direction of the magnetic field is the positive direction, and as shown in FIG. 10, the AC current ACI and the output If the phase difference from the voltage Vs is out of the predetermined range, it is determined to be in the negative direction. Here, the direction of the magnetic field is defined as the positive direction means that the direction of the magnetic field measured by the magnetic field sensor 6 (search coil 62) is the same as the direction of the magnetic field generated around the U-phase winding 24U. The fact that the direction of the magnetic field is negative is defined as the direction of the magnetic field measured by the magnetic field sensor 6 (search coil 62) is opposite to the direction of the magnetic field generated around the U-phase winding 24U. .. Here, the CPU 70 of the diagnostic unit 10 that compares the phase difference between the AC current ACI and the output voltage Vs and determines the direction of the magnetic field based on the phase difference is an example of the implementation configuration corresponding to the "processor" in the present invention. is there. The mode in which the direction of the magnetic field is positive corresponds to the "first direction" in the present invention, and the mode in which the direction of the magnetic field is negative corresponds to the "second direction" in the present invention. is there.

In this way, the direction of the magnetic field measured by the magnetic field sensor 6 (search coil 62) is determined in order to more accurately diagnose whether or not a short circuit has occurred in the U-phase winding 24U. That is, in the centralized winding, due to the configuration in which a ferromagnetic material is used as the material of the teeth 22b, even if a slight short circuit such as a short circuit occurs, the direction is opposite to the direction of the magnetic field created by other parts where the short circuit does not occur. Since a strong magnetic field is generated, the difference between the case where a short circuit occurs and the case where a short circuit does not occur may be unclear only by the strength of the magnetic field (magnitude of output voltage Vs). It may be difficult to determine the occurrence, but by considering the direction of the magnetic field, the difference between the case where a short circuit occurs and the case where a short circuit does not occur becomes clear, so that a short circuit occurs. Can be reliably diagnosed.

Then, a process of adding a positive with respect to the determined direction of the magnetic field to the stored output voltage Vs is executed. That is, the process of replacing the output voltage Vs previously stored in the RAM 74 (without the positive / negative information added) with the output voltage Vs to which the positive / negative information is added is executed. Thus the process of storing the output voltage Vs negative information is added at the measurement position t ₀ to RAM74 is complete, the search coil 62 moves the magnetic field sensor 6 to come to measuring position t _1, the measurement position t ₁ The output voltage Vs is measured in the above, the direction of the magnetic field is determined based on the relationship between the output voltage Vs and the AC current ACI, and the output voltage Vs previously stored in the RAM 74 (without positive / negative information added) is determined. The process of replacing with the output voltage Vs to which the positive / negative information is added is executed.

Such processing is repeatedly executed while moving to the measurement position t _L by a predetermined interval d. That is, the position of the search coil 62 is moved from the base of the teeth 22b (the end of the connection of the teeth 22b to the yoke 22a) toward the tip of the teeth 22b (the end of the stator 22 near the center) of the axis CL2 of the teeth 22b. The above-mentioned processing (processing from measuring the output voltage Vs to which the positive / negative information is not added until replacing it with the output voltage Vs to which the positive / negative information is added) is executed while moving by a predetermined interval d along the extending direction of. To do. The predetermined interval d can be set to a value substantially equal to the distance between the centers of the coils constituting the three-

phase windings

24U, 24V, and 24W, for example.

Then, to execute a process for determining the respective measuring position _{t i (i = 0 ~ L} ) variant of the output voltage Vs of each of positive and negative information is added. Specifically, the output voltage Vs is the first pattern in which all the output voltages Vs are positive, or the second pattern in which the output voltage Vs changes from positive to negative and then changes from negative to positive again. It is determined whether it is the third pattern in which the negative or positive changes from positive or negative to negative or positive, or the fourth pattern in which the output voltage Vs changes in negative.

In the case of the first pattern, it is determined that a short circuit has not occurred in the U-phase winding 24U, and the determination result is transmitted to the display device 12. In the case of the second pattern, the process of comparing the absolute value of the output voltage Vs to which negative information is added with the threshold value Vsref1 is executed. Here, the threshold value Vsref1 is set when a short circuit occurs between windings adjacent to the axis CL2 direction of the U-phase winding 24U (the axis CL2 direction of the teeth 22b or the extending direction of the teeth 22b). It is a value set to determine the location where a short circuit occurs, and in the present embodiment, it is configured to be obtained in advance by an experiment or the like and stored in the ROM 72. The threshold value Vsref1 is an example of an implementation configuration corresponding to the "second threshold value" in the present invention.

As a result of comparing the absolute value of the output voltage Vs to which negative information is added and the threshold value Vsref1, if there is an output voltage Vs determined to be equal to or higher than the threshold value Vsref1, it is first determined to be equal to or higher than the threshold value Vsref1. in output voltage Vs of the measurement position _{t i (i = 0 ~ L} ), the winding adjacent to the axial line CL2 direction of the U-phase winding 24U (axial line CL2 direction of the tooth 22b or, the extending direction of the teeth 22b) It is determined that a short circuit has occurred between them, and the determination result is transmitted to the display device 12.

Further, the output voltage if the variant of Vs is determined to be the third pattern, the measurement position of the output voltage Vs changes from a positive or negative negatively or positively _{t i (i = 0 ~ L} ) is, teeth It is determined whether or not the end portion of 22b (the extending end portion of the teeth 22 or the end portion of the teeth 22 on the connection portion side to the stator 22), that is, the measurement position t ₀ or the measurement position t _L. If the measured position of the output voltage Vs changes from a positive or negative negatively or positively _{t i (i = 0 ~ L} ) is not a measurement position t _0, t _L is the manner in which the output voltage Vs changes from positive to negative if, in the measurement position of the initially added negative information output voltage _{Vs t i (i = 0 ~} L), determines that a short circuit between the layers of the U-phase winding 24U is occurring, the output voltage Vs if aspects but which changes from negative to positive, in the measurement position of the output voltage Vs negative information immediately before the output voltage Vs turns from negative to positive is added _{t i (i = 0 ~ L} ), U -phase winding It is determined that a short circuit has occurred between the layers of the wire 24U, and the determination result is transmitted to the display device 12.

On the other hand, the measurement position of the output voltage Vs changes from a positive or negative negatively or positively _{t i (i = 0 ~ L} ) is the measurement position t _0, in the case of t _L, a negative information added output voltage Whether or not the absolute value of Vs is equal to or greater than the threshold Vsref2, or the difference between the peak value of the output voltage Vs to which positive information is added and the peak value of the output voltage Vs to which negative information is added is positive. measurement position of the peak value of the output voltage Vs information is added t _{i (i} = 0 ~ L) and the measurement position of the peak value of the output voltage Vs negative information is added t _i and _(i = 0 ~ L) It is determined whether or not the absolute value of the change rate CR calculated by dividing by the difference is equal to or greater than the reference change rate BCR. Here, in the threshold value Vsref2 and the reference change rate BCR, a short circuit occurs between the windings in which the U-phase winding 24U is adjacent to the axis CL2 direction (the axis CL2 direction of the teeth 22b or the extension direction of the teeth 22b). It is a value set to determine whether the U-phase winding 24U has a short circuit between layers, and in the present embodiment, it is obtained in advance by an experiment or the like and stored in the ROM 72. It was configured to be kept. The threshold value Vsref2 is an example of an implementation configuration corresponding to the "threshold value" in the present invention.

If the absolute value of the output voltage Vs to which negative information is added is equal to or greater than the threshold Vsref2, or the absolute value of the rate of change CR is greater than or equal to the reference rate of change BCR, the U-phase winding 24U at the measurement positions t ₀ and t _L. It is determined that a short circuit has occurred between the windings adjacent to the axis CL2 direction (the axis CL2 direction of the teeth 22b or the extending direction of the teeth 22b), and the determination result is transmitted to the display device 12. On the other hand, if the absolute value of the output voltage Vs to which negative information is added is less than the threshold value Vsref2, or the absolute value of the change rate CR is less than the reference change rate BCR, the U phase winding is performed at the measurement positions t ₀ and t _L. It is determined that a short circuit has occurred between the layers of the wire 24U, and the determination result is transmitted to the display device 12.

Further, when it is determined that the change mode of the output voltage Vs is the fourth pattern, it is determined that a short circuit has occurred between the layers of the U-phase winding 24U, and the determination result is transmitted to the display device 12. .. Each measurement position _{t i (i = 0 ~ L} ) for each of the output voltage Vs of the variants of positive and negative information is added occurred in the U-phase winding 24U based on (first, second, third and fourth patterns) Determining the mode of the short circuit, that is, whether a short circuit has occurred between the windings adjacent to the U-phase winding 24U in the axis CL2 direction, or whether a short circuit has occurred between the layers of the winding. The CPU 70 is an example of an implementation configuration corresponding to the "processor" in the present invention.

Next, FIGS. 11 to 11 show the results of experiments in which the above-mentioned first, second, third, and fourth patterns of short-circuit occurrence are diagnosed using the winding short-circuit diagnostic apparatus 1 of the present invention according to the present embodiment. This will be described with reference to 26. In the experiment, a solenoid coil in which two layers of windings were wound in a range of 50 mm in the center of the longitudinal direction was used, leaving only 5 mm at both ends in the longitudinal direction of a rectangular body made of iron material having a length of 60 mm, in the longitudinal direction of the solenoid coil. A magnetic field sensor 6 is installed so that the search coil 62 is arranged at one end (hereinafter referred to as "measurement start point"), and the magnetic field sensor 6 is set to 2 mm (in the longitudinal direction of the rectangular body) of the solenoid coil. The magnetic field was measured by changing the measurement point to the other end in the longitudinal direction of the solenoid coil (hereinafter referred to as "measurement end point") while shifting the distance between the centers.

In the experiment, the solenoid coil SLC1 (FIGS. 11 and 19) having a two-layer winding structure without a short circuit, and the solenoid coil at a position ₃₀ mm from the measurement start point (measurement position t30, FIGS. 12 and 20). A two-layer winding structure solenoid coil SLC2 in which a short circuit is generated between windings adjacent to each other in the longitudinal direction of the coil, and windings adjacent to the longitudinal direction of the solenoid coil at the measurement start point (measurement position t ₀ , FIGS. 13 and 21). A short circuit is generated between the windings of the solenoid coil SLC3 having a two-layer winding structure in which a short circuit is generated between the wires, and the windings adjacent to each other in the longitudinal direction of the solenoid coil at the measurement end point (measurement position t ₅₀ , FIGS. 14 and 22). Two-layer winding structure solenoid coil SLC4, two-layer winding structure solenoid coil SLC5 in which a short circuit occurs between the winding layers at a position 37 mm from the measurement start point (FIGS. 15 and 23), measurement end point (FIG. 15 and FIG. 23). In FIGS. 16, 17, 24 and 25), solenoid coils SLC6 and SCL7 having a two-layer winding structure in which a short circuit is generated between the winding layers (the solenoid coil SCL6 and the solenoid coil SCL7 have the same short circuit location. A solenoid coil SLC8 having a three-layer winding structure in which a short circuit occurs between the winding layers at the measurement start point (measurement position t ₀ , FIGS. 18 and 26) is used. And said. An alternating current ACI of about 70 mA was applied between the terminals of the solenoid coil (the frequency at this time is 1 kHz).

In the solenoid coil SLC1 (see FIG. 19), as shown in FIG. 11, the output voltage Vs has a positive value in the entire range from the measurement position t ₀ (measurement start point) to the measurement position t ₅₀ (measurement end point). Indicated. As a result, it was confirmed that if the change mode of the output voltage Vs is the first pattern, it can be determined that a short circuit has not occurred in the winding.

In the solenoid coil SLC2 (see FIG. 20), as shown in FIG. 12, the output voltage Vs becomes negative from the measurement position t ₂₈ (point 28 mm from the measurement start point), and the measurement position t ₃₄ (point 34 mm from the measurement start point). ), The output voltage Vs is positive again. As a result, it was confirmed that when the change mode of the output voltage Vs is the second pattern, it can be determined that a short circuit has occurred between the windings adjacent to each other in the longitudinal direction of the windings. It was also confirmed that it was possible to identify that a short circuit occurred at the measurement position t ₃₀ (a point 30 mm from the measurement start point) where the absolute value of the output voltage Vs was equal to or higher than the threshold value Vsref1.

In the solenoid coil SLC3 (see FIG. 21), as shown in FIG. 13, the output voltage Vs is negative at the measurement position t ₀ (measurement start point), and the measurement position t ₄ (point 4 mm from the measurement start point). output voltage Vs is turned positive, the output voltage Vs to the measurement position t _{50 (measurement} end point) has remained positive while in. Here, the absolute value of the output voltage Vs at the measurement position t ₀ (measurement start point) is equal to or higher than the threshold value Vsref2 (dashed line in FIG. 13). Further, the absolute value of the slope (change rate CR of output voltage Vs) of the straight line (two-dot chain line in FIG. 13) connecting the positive peak value and the negative peak value of the output voltage Vs is the reference change rate BCR (FIG. 13). 13 solid lines) or more. As a result, the change mode of the output voltage Vs is the case of the third pattern, and the short circuit is the end portion of the teeth 22b (the extending end portion of the teeth 22b or the end portion of the teeth 22b on the connection portion side to the stator 22). If the absolute value of the output voltage Vs is equal to or greater than the threshold Vsref2, or if the rate of change CR of the output voltage Vs is greater than or equal to the reference rate of change BCR, the winding adjacent to the teeth 22b in the longitudinal direction. It was confirmed that it can be determined that a short circuit has occurred between the lines. It was also confirmed that it was possible to identify that a short circuit occurred at the measurement position t ₀ (measurement start point) where the absolute value of the output voltage Vs was equal to or higher than the threshold value Vsref 1 (broken line in FIG. 13).

In the solenoid coil SLC4 (see FIG. 22), as shown in FIG. 14, the output voltage Vs turns negative at the measurement position t ₄₈ ( ₄₈ mm from the measurement start point) and reaches the measurement position t ₅₀ (measurement end point). The output voltage Vs remains negative until. The absolute value of the output voltage Vs at the measurement position t ₅₀ (measurement end point) is equal to or higher than the threshold value Vsref2 (dashed line in FIG. 14). Further, the absolute value of the slope (change rate CR of output voltage Vs) of the straight line (two-dot chain line in FIG. 14) connecting the positive peak value and the negative peak value of the output voltage Vs is the reference change rate BCR (FIG. 14). 14 solid lines) or more. As a result, the change mode of the output voltage Vs is the case of the third pattern, and the short circuit is the end portion of the teeth 22b (the extending end portion of the teeth 22b or the end portion of the teeth 22b on the connection portion side to the stator 22). If the absolute value of the output voltage Vs is equal to or greater than the threshold Vsref2, or if the rate of change CR of the output voltage Vs is greater than or equal to the reference rate of change BCR, the teeth 22b are adjacent to each other in the longitudinal direction. It was confirmed that it can be determined that a short circuit has occurred between the windings. It was also confirmed that it was possible to identify that a short circuit occurred at the measurement position t ₅₀ (measurement end point) where the absolute value of the output voltage Vs was equal to or higher than the threshold value Vsref1 (broken line in FIG. 14).

In the solenoid coil SLC5 (see FIG. 23), as shown in FIG. 15, the output voltage Vs turns negative at the measurement position t ₃₈ ( ₃₈ mm from the measurement start point) and reaches the measurement position t ₅₀ (measurement end point). The output voltage Vs remains negative until. As a result, when the change mode of the output voltage Vs is the third pattern and the short circuit occurs at a position other than the end of the teeth 22b, that is, at a measurement position other than the measurement positions t ₀ and t ₅₀ (measurement end point). If so, it was confirmed that it can be determined that a short circuit has occurred between the layers of the winding. It was also confirmed that it was possible to identify that a short circuit had occurred at the measurement position t ₃₈ (a point 38 mm from the measurement start point) where the output voltage Vs changed from positive to negative.

In the solenoid coil SLC6 (see FIG. 24), as shown in FIG. 16, the output voltage Vs turns negative at the measurement position t50 (a position ₅₀ mm from the measurement start point). The absolute value of the output voltage Vs at the measurement position t ₅₀ (measurement end point) is less than the threshold value Vsref2 (dashed line in FIG. 16). Further, the absolute value (change rate CR of output voltage Vs) of the slope of the straight line (two-dot chain line in FIG. 16) connecting the positive peak value and the negative peak value of the output voltage Vs is the reference change rate BCR (FIG. 16). It is less than 16 solid lines). As a result, the change mode of the output voltage Vs is the case of the third pattern, and the short circuit is the end portion of the teeth 22b (the extending end portion of the teeth 22b or the end portion of the teeth 22b on the connection portion side to the stator 22). If the absolute value of the output voltage Vs is less than the threshold Vsref2, or if the change rate CR of the output voltage Vs is less than the reference change rate BCR, a short circuit occurs between the winding layers. It was confirmed that it can be determined that the voltage is correct. The output voltage Vs is shorted at the measurement position t ₅₀ that switches from positive to negative _(measurement end point) was that also confirmed that it is possible to identify the occurring.

As shown in FIG. 25, the solenoid coil SLC7 basically causes a short circuit at the same position as the solenoid coil SLC6, but the measurement start point and the measurement end point are opposite to those of the solenoid coil SLC6. .. That is, in the solenoid coil SLC7, the measurement starting point has become a measurement position t _50, the measurement end point is in the measurement position _0. In the solenoid coil SLC7, as shown in FIG. 17, the output voltage Vs shows a negative value at the measurement position t ₅₀ (measurement start point), and then the output voltage Vs becomes negative at the measurement position t ₄₈ (point 2 mm from the measurement start point). After turning positive, the output voltage Vs has remained positive until the measurement position t ₀ (measurement end point). Here, the absolute value of the output voltage Vs at the measurement position t ₅₀ (measurement start point) is less than the threshold value Vsref2 (dotted line in FIG. 17). Further, the absolute value (change rate CR of output voltage Vs) of the slope of the straight line (two-dot chain line in FIG. 17) connecting the positive peak value and the negative peak value of the output voltage Vs is the reference change rate BCR (FIG. 17). It is less than 17 solid lines). As a result, the change mode of the output voltage Vs is the case of the third pattern, and the short circuit is the end portion of the teeth 22b (the extending end portion of the teeth 22b or the end portion of the teeth 22b on the connection portion side to the stator 22). If the absolute value of the output voltage Vs is less than the threshold Vsref2, or if the change rate CR of the output voltage Vs is less than the reference change rate BCR, a short circuit occurs between the winding layers. It was confirmed that it can be determined that the voltage is correct. It was also confirmed that it was possible to identify that a short circuit had occurred at the measurement position t ₅₀ (measurement start point) where the output voltage Vs changed from positive to negative.

As shown in FIG. 26, the solenoid coil SLC8 has a three-layer winding structure unlike the solenoid coils SLC1 to 7 (the solenoid coils SLC1 to 7 have a two-layer winding structure). In the solenoid coil SLC8 (see FIG. 26), as shown in FIG. 18, the output voltage Vs has a negative value in the entire range from the measurement position t ₀ (measurement start point) to the measurement position t ₅₀ (measurement end point). Indicated. As a result, it was confirmed that if the change mode of the output voltage Vs is the fourth pattern, it can be determined that a short circuit has occurred between the winding layers. In this case, the location where the short circuit occurs cannot be specified.

According to the winding short-circuit diagnostic apparatus 1 of the present invention according to the embodiment described above, the magnetic field generated in the three-

phase windings

24U, 24V, 24W wound for each tooth 22b is applied in the extending direction of the tooth 22b. while measuring a predetermined interval d along the three-

phase windings

24U, 24V, by comparing the phase difference between the alternating current ACI flowing to 24W and measurement position _{t i (i = 0 ~ L} ) for each of the output voltage Vs The direction of the magnetic field measured by the magnetic field sensor 6 (search coil 62) is determined, and the three-phase winding 24U depends on which of the patterns 1 to 4 the change mode of the output voltage Vs in consideration of the direction of the magnetic field corresponds to. , 24V, 24W is wound around the teeth 22b because it is configured to determine whether a short circuit has occurred between windings adjacent to the teeth 22b in the extending direction or between layers. It is possible to identify how the three-

phase windings

24U, 24V, and 24W are short-circuited. As a result, it is possible to obtain mode information that tends to cause a short circuit. Therefore, by feeding back the information to the design stage, measures such as how to wind the winding and the structure of the teeth for winding the winding can be taken. Can be applied. As a result, the short-circuit occurrence rate of the rotating machine such as the electric motor 2 and the generator can be reduced, which can contribute to quality improvement.

In the present embodiment, the magnetic field sensor 6 having one search coil 62 in which the coil is wound for several turns to several tens of turns is moved along the extending direction of the axis CL2 from the measurement position t ₀ to the measurement position t _L. it is configured to measure the magnetic field (output voltage Vs) at each measurement position _{t i (i = 0 ~ L} ), it is not limited thereto while. For example, as shown in the magnetic field sensor 106 of the modified example illustrated in FIG. 27, the magnetic field sensor 106 has a search coil 62 wound about several tens turns from several turns of coils, each measurement position the search coil 62 t _i (i = 0 ~ L) arranged for each may be configured to measure a magnetic field (output voltage Vs) at each measurement position _{t i (i = 0 ~ L} ) at a time. According to this configuration, the time for moving the search coil 62 can be omitted, so that the measurement time can be shortened and the measurement can be simplified.

In the present embodiment, the phase difference between the AC current ACI and the output voltage Vs is compared, and the direction of the magnetic field is determined based on the phase difference, but the present invention is not limited to this. For example, in determining the direction of the magnetic field, the phase difference between the AC voltage and the output voltage Vs may be compared, and the direction of the magnetic field may be determined based on the phase difference.

In the present embodiment, the strength of the magnetic field is measured from the root portion of the teeth 22b (the end portion of the teeth 22b connected to the yoke 22a) toward the tip portion of the teeth 22b (the end portion near the center of the stator 22). At the same time, the configuration is such that the direction of the magnetic field is determined, but the present invention is not limited to this. For example, contrary to the present embodiment, the magnetic field is applied from the tip of the tooth 22b (the end near the center of the stator 22) to the root of the tooth 22b (the end of the connection of the tooth 22b to the yoke 22a). It may be configured to measure the strength and perform a process of determining the direction of the magnetic field.

In the present embodiment, the change mode of the output voltage Vs is the case of the third pattern, and the short circuit is on the end portion of the teeth 22b (the extending end portion of the teeth 22 or the connection portion side of the teeth 22 to the stator 22). If it occurs at the end), whether or not the absolute value of the output voltage Vs to which negative information is added is equal to or greater than the threshold value Vsref2, and the absolute value of the change rate CR of the output voltage Vs is the reference change. The configuration is such that both determination of whether or not the ratio is BCR or higher is performed, but the present invention is not limited to this. For example, whether or not the absolute value of the output voltage Vs to which negative information is added is equal to or greater than the threshold value Vsref2, or whether or not the absolute value of the change rate CR of the output voltage Vs is equal to or greater than the reference change rate BCR. The configuration may be such that only one is determined. Further, whether or not the absolute value of the output voltage Vs to which negative information is added is equal to or higher than the threshold Vsref2, and whether or not the absolute value of the change rate CR of the output voltage Vs is equal to or higher than the reference change rate BCR. When both judgments are made, only when both are "OK", a short circuit occurs between the windings adjacent to the axis CL2 direction of the U-phase winding 24U (the axis CL2 direction of the teeth 22b or the extension direction of the teeth 22b). If both are "No", it may be determined that a short circuit has occurred between the layers of the U-phase winding 24U.

In the present embodiment, the frequency of the AC voltage applied to each of the UV phase, the VW phase, and the WU phase is set to 1 kHz by the voltage oscillator 4, but the frequency is not limited to this. If the frequency of the AC voltage applied by the voltage oscillating unit 4 between the UV phase, the VW phase, and the WU phase is higher than the frequency of the commercial AC power supply of 60 Hz (or 50 Hz), the frequency will be any value. It may be.

In the present embodiment, the voltage oscillating unit 4 sets the AC voltage applied to each of the UV phase, the VW phase, and the WU phase to 200 volts or less, but the present invention is not limited to this.

In the present embodiment, the predetermined interval d, which is the interval for moving the search coil 62, is set to a value substantially equal to the distance between the centers of the coils constituting the three-

phase windings

24U, 24V, and 24W. Not limited to.

In the present embodiment, the short circuit of the three-

phase windings

24U, 24V, 24W in the stator 22 having the teeth 22b in which the three-

phase windings

24U, 24V, 24W are directly wound is diagnosed. Not limited to. For example, a configuration for diagnosing a short circuit of the three-

phase windings

24U, 24V, 24W in a rotor 32 having a slot in which the three-

phase windings

24U, 24V, 24W are directly wound may be used. In this case, a short circuit of the three-

phase windings

24U, 24V, and 24W may be diagnosed with the stator 22 removed from the motor 2 and only the rotor 32.

The present embodiment shows an example of a mode for carrying out the present invention. Therefore, the present invention is not limited to the configuration of the present embodiment. The correspondence between each component of the present embodiment and each component of the present invention is shown below.

1 Winding short circuit diagnostic device (winding short circuit diagnostic device)
2 Electric motor (rotating machine)
4 Voltage oscillator (voltage oscillator)
6 Magnetic field sensor (magnetic field sensor)
8 A / D conversion unit 10 Diagnosis unit 22 Stator (stator)
22a York 22b Teeth (Teeth)
24U U phase winding (winding)
24Us Closed Loop 24V V-Phase Winding
24W W phase winding (winding)
26 Connection terminal 32 Rotor (rotor)
62 Search coil (search coil)
64 Amplifier 70 CPU (Processor)
72 ROM
74 RAM (memory)
106 Magnetic field sensor (Magnetic field sensor)
ACI alternating current (alternating current)
L1 signal line L2 signal line L3 signal line L4 signal line Vs output voltage (output voltage)
CL1 axis CL2 axis H ₀ field strength H _s magnetic field intensity I _s current S short t ₀ the measurement position t _L measurement position t _i measured position d predetermined distance h predetermined distance Vsref1 threshold (second threshold value)
Vsref2 threshold (threshold)
SLC1 Solenoid Coil SLC2 Solenoid Coil SLC3 Solenoid Coil SLC4 Solenoid Coil SLC5 Solenoid Coil SLC6 Solenoid Coil SLC7 Solenoid Coil SLC8 Solenoid Coil

Claims

A winding short-circuit diagnostic device that diagnoses a short-circuit of a winding in a stator or rotor of a rotor in which a plurality of teeth arranged at substantially equal intervals in the circumferential direction are centrally wound.
A voltage oscillator configured to apply an AC voltage between the terminals of the winding,
A magnetic field sensor that measures the strength of the magnetic field generated in the winding wound for each tooth in response to the application of the AC voltage at predetermined intervals along the extending direction of the tooth.
A memory that stores the AC voltage or the AC current flowing through the winding due to the AC voltage and the strength of the magnetic field.
The direction of the magnetic field stored in the memory is determined for each measurement position based on the AC voltage or the AC current and the strength of the magnetic field, and all the determined directions of the magnetic field are the first directions. In the case of one pattern, it is determined that no short circuit has occurred in the winding, and after the direction of the magnetic field changes from the first direction to the second direction opposite to the first direction, In the case of the second pattern changing from the second direction to the first direction, it is determined that a short circuit has occurred between the windings adjacent to the extending direction of the teeth, and the direction of the magnetic field is the first. In the case of the third pattern, which changes from the one direction or the second direction to the second direction or the first direction and then changes in the second direction or the first direction, and all the directions of the magnetic field are the first. In the case of the fourth pattern in two directions, a processor that determines that a short circuit has occurred between the layers of the winding and a processor.
A winding short circuit diagnostic device.
In the case of the third pattern, the processor changes the direction of the magnetic field from the first direction or the second direction to the second direction or the first direction in the extending direction of the teeth. If it occurs at the end, the strength of the magnetic field in the second direction is compared with the threshold, and if the strength of the magnetic field is equal to or greater than the threshold, and / or the direction of the magnetic field is the first. The absolute value of the change rate of the magnetic field strength when changing from one direction or the second direction to the second direction or the first direction is compared with the reference change rate, and the absolute value of the change rate is the said. When it is equal to or more than the reference change rate, it is determined that a short circuit has occurred between the windings adjacent to the longitudinal direction of the teeth, and when the strength of the magnetic field is less than the threshold value, and / or the change. The winding short circuit diagnostic apparatus according to claim 1, wherein when the absolute value of the ratio is less than the reference change ratio, it is determined that a short circuit has occurred between the layers of the winding.
The memory can store the strength of the magnetic field in association with the measurement position.
When the processor determines that a short circuit has occurred between the layers of the winding, the processor determines that the winding has a short circuit at the measurement position where the direction of the magnetic field is first in the second direction. The winding short circuit diagnostic apparatus according to claim 1 or 2.
The memory can store the strength of the magnetic field in association with the measurement position.
When the processor determines that a short circuit has occurred between the windings adjacent to the teeth in the longitudinal direction, the processor compares the strength of the magnetic field in the second direction with the second threshold value, and first performs the first. The winding according to any one of claims 1 to 3, wherein it is determined that a short circuit has occurred in the winding at the measurement position associated with the strength of the magnetic field determined to be 2 thresholds or more. Line short circuit diagnostic device.
The winding short-circuit diagnostic apparatus according to any one of claims 1 to 4, wherein the voltage oscillating unit applies an AC voltage having a frequency higher than a commercial frequency between the terminals of the winding.
The winding short-circuit diagnostic apparatus according to any one of claims 1 to 5, wherein the voltage oscillating unit applies an AC voltage of 200 volts or less between the terminals of the winding.
The magnetic field sensor has a search coil for measuring the strength of the magnetic field, and when measuring the strength of the magnetic field, the axial direction of the search coil is the axial direction of the winding wound around the tooth. The winding short circuit diagnostic apparatus according to any one of claims 1 to 6, which is arranged so as to be parallel to.
The magnetic field sensor has a search coil for measuring the strength of the magnetic field, and when measuring the strength of the magnetic field, it is virtual when viewed from one side of the stator or the rotor in the axial direction. The winding short circuit diagnostic apparatus according to any one of claims 1 to 7, wherein the axis of the search coil on the projection surface is arranged so as to overlap the axis of the winding wound around the tooth.
A winding short-circuit diagnostic method for diagnosing a short-circuit of the winding in a stator or a rotor of a rotor in which a plurality of teeth arranged at substantially equal intervals in the circumferential direction are centrally wound.
(A) An AC voltage is applied between the terminals of the winding wound for each tooth.
(B) The strength of the magnetic field generated in the winding wound for each tooth in response to the application of the AC voltage is measured at predetermined intervals along the extending direction of the tooth.
(C) The AC voltage or the AC current flowing through the winding due to the AC voltage and the measured strength of the magnetic field are stored.
(D) The direction of the magnetic field at each predetermined interval stored is determined based on the AC voltage or the AC current and the strength of the magnetic field.
(E) In the case of the first pattern in which all the determined directions of the magnetic field are the first directions, it is determined that no short circuit has occurred in the winding, and the direction of the magnetic field stored in the memory is In the case of the second pattern, which changes from the first direction to the second direction opposite to the first direction and then changes from the second direction to the first direction, the extending direction of the teeth. It is determined that a short circuit has occurred between the windings adjacent to the winding, and the direction of the magnetic field stored in the memory changes from the first direction to the second direction, and then changes in the second direction. A winding short circuit diagnosis method for determining that a short circuit has occurred between the layers of the winding in the case of the third pattern or in the case of the fourth pattern in which all the directions of the magnetic fields are in the second direction.
The step (e) is the case of the third pattern, and the change in the direction of the magnetic field from the first direction or the second direction to the second direction or the first direction is the extension of the teeth. If it occurs at the end of the exit direction, the strength of the magnetic field in the second direction is compared with the threshold, and if the strength of the magnetic field is equal to or greater than the threshold, and / or the direction of the magnetic field. Compares the absolute value of the rate of change in the strength of the magnetic field when changes from the first direction or the second direction to the second direction or the first direction with the reference rate of change, and the absolute value of the rate of change is absolute. When the value is equal to or more than the reference change rate, it is determined that a short circuit has occurred between the windings adjacent to the longitudinal direction of the teeth, and the strength of the magnetic field is less than the threshold value and / or. The winding short circuit diagnosis method according to claim 9, further comprising a step of determining that a short circuit has occurred between the layers of the winding when the absolute value of the change rate is less than the reference change rate.