JPS59110395A - Brushless rotary electric machine - Google Patents

Abstract

PURPOSE:To enable to detect the ground-fault trouble of a field circuit without contact by providing a signal processor for comparing the generated magnetic flux of a detecting excitation winding with the residual magnetic flux by a field ground-fault detector to generates a signal when the generated magnetic flux exceeds the residual magnetic flux. CONSTITUTION:A rotor 2 which rotates oppositely to a rotor 1 of a synchronous machine supplies the output of an AC excitor armature 3 to a field winding 5 through a rotary rectifier 4. The output of an AC exciting auxiliary winding 8 is supplied separately from field circuits 6, 7 to the AC input terminal of a power source controller 9, the negative side terminal of the DC output side is grounded to the body of the rotor 2, and the positive side terminal is connected to the circuit 7 through a detecting excitation winding 12. Power is supplied to the winding 8 without brush by DC-exciting the field winding 13. A detector 14 is magnetically coupled to the winding 12, and the output of the detector 14 is connected to an alarm unit 19 through a signal processor 15. The processor 15 compares the detection signal with the amount of a bias setter 23 by a comparator 15 and outputs a ground-fault trouble occurrence signal. In this manner, the ground-fault trouble can be detected without contact.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a brushless rotating electric machine, and more particularly to a brushless rotating electric machine equipped with a detection device for non-contact detecting a ground fault in a rotor field circuit on a synchronous machine side. .

[Technical background of the invention and its problems]

In a brushless rotating electric machine, for example, a brushless synchronous machine, there are no brushes, slip rings, etc., so electrical quantities such as voltage and current on the rotor side cannot be directly measured from the fixed side. For this reason, the conventional method of measuring was to separately install a measuring brush and a slip ring, but the benefits of using a brushless design to eliminate the troublesomeness of the original brush were not fully utilized, and maintenance became troublesome. In addition to this, there was also the problem of structural complexity.

Therefore, there is a tendency to measure the electrical quantities of the rotor using non-contact measuring devices without using brushes, slip rings, etc., and communication between the rotating part and the fixed part is made using magnetism, radio waves, light, sound waves, etc. , devices that use magnetism are simple and common. The present applicant has already proposed a structure for a non-contact field circuit ground fault detection device using such magnetism in Japanese Patent Laid-Open No. 57-88855. In other words, a coil that forms a magnetic pole is installed on the outer periphery of the rotating part, and when a ground fault current flows through this coil, the magnetic flux is measured by a detection unit installed on the fixed part, thereby detecting a ground fault in a non-contact manner. It is.

However, in such structures, the coil that generates magnetic flux is fixed to the rotating part with bolts, and the bolts are fixed against the magnetic poles of the magnetic circuit and centrifugal force. Generally, the bolts are made of steel and have high magnetic permeability. has a high residual magnetization, and once a current is applied to the coil, the magnetization remains even after the current is turned off. Therefore, the detection section detects magnetic flux containing residual magnetization, which may cause the alarm device to malfunction. For this reason, regular maintenance and inspection are required to replace and demagnetize the bolts, and if a non-magnetic material is used as the material for the bolts, the magnetic resistance of the magnetic circuit increases, resulting in a decrease in the level of magnetic flux density and detection. There were drawbacks such as a decrease in the S/N ratio of the signal.

[Purpose of the invention]

The present invention has been made in view of the above drawbacks, and an object of the present invention is to provide a brushless rotating electric machine equipped with a detection device that can accurately detect a ground fault in a field circuit in a non-contact manner.

[Summary of the invention]

That is, the field ground fault detection device is provided with a signal processing circuit that compares the magnetic flux generated by the detection excitation winding with the residual magnetic flux and generates a signal when the generated magnetic flux exceeds the residual magnetic flux. The signal processing circuit includes (1) a comparison circuit that compares the bias setting circuit for residual magnetic flux and the generated magnetic flux, (2) a comparison circuit that compares the initial value storage circuit that stores the normal magnetic flux value and the generated magnetic flux, (3) ) There is a signal processing circuit that compares the respective magnetic fluxes of the residual magnetized dummy member and the member of the detection excitation winding.

[Embodiments of the invention]

The present invention will now be described with reference to one embodiment shown in the drawings. FIG. 1 shows the first implementation row, in which the rotor (2) rotating opposite the stator (1) of the synchronous machine is connected to the AC exciter armature (3).
) is converted to DC via the rotary rectifier (4), and then the positive field circuit (6) is connected to the field winding (5) of the synchronous machine.
and supplies an excitation current via the negative field circuit. Separately from the field circuit (6) (7), the output of the AC excitation auxiliary winding (8) is connected to the rotor (2) via a protective fuse (10) to the AC input terminal of the power supply control circuit (9). Connect the negative side terminal on the DC output side to point E of the rotor (2) body and ground it, and connect the positive side terminal to the current limiting resistor (11) and the detection excitation winding (1).
2) to the negative field circuit (7) of the rotary rectifier (4).
). Auxiliary winding (8) is armature winding (3)
Electric power is supplied in a brushless manner by winding the AC exciter field winding (13) in the same iron core slot (not shown) and exciting the AC exciter field winding (13) with DC current. A detection section (14) provided on the fixed section side facing the detection excitation winding (12) is magnetically coupled with, for example, a Hall element, and the output of the detection section (14) is sent to the signal processing circuit (
15) to an alarm device (16). The power supply control circuit (9) incorporates a light-receiving element device (not shown) that receives light from the light-emitting element device (17) of the fixed part and opens and closes the rectifier circuit.

FIGS. 2 and 3 show a detection device, in which a detection excitation winding (12) has a ring α camphor attached to the rotating shaft an, and a ring (
A coil (19) with a winding (19b) wound around an insulating ring (19a) is inserted into the recess (18a) provided in the bolt (2).
0), and an iron core (22) to which a detection element (21) such as a Hall element is attached is attached to the fixed part at a position opposite to the bolt (20).

The magnetic flux generated by the coil (19) is detected in a non-contact manner by the detection unit (l4). Since the magnetization due to the flow of the ground fault current is added, the signal amount detected by the detection section (14) exceeds the above-mentioned bypass amount, and the comparator circuit (24) outputs a signal indicating that a ground fault has occurred. put out.

FIG. 5 shows a second embodiment, in which a signal processing circuit (15)
At this point, a memory circuit (25) which automatically stores and sets a signal during normal operation due to residual magnetization of the bolt (21) as an initial value outputs a signal from the comparator circuit (24) to notify that a ground fault has occurred. Therefore, even if the residual magnetization decreases due to aging, if the initial value is stored and reset at appropriate time intervals, it is possible to accurately detect a ground fault.

Fig. 6 shows a third embodiment, and the difference from Fig. 3 is that a plurality of detection parts (14) are provided on the fixed part, and a detection excitation winding (12) is provided on the rotating part side. A dummy bolt (26) of the same shape and material as the bolt (20) attaches the balance weight (27) to the recess (18a).

The bolt (20) of the detection excitation winding (14) is previously saturated magnetized in the direction in which it will be magnetized by the current flowing during a field ground fault, and the dummy bolt (26) is also saturated magnetized in the same way.
At the same time as the detection excitation winding (14) faces the detection part (14), the dummy bolt (26) faces the other detection part (14). Bolt (20) and dummy bolt (26)
The respective magnetic fluxes are measured by the detection unit (14), compared by the comparison circuit (28) of the signal processing circuit (15) as shown in Fig. 7, and the difference is determined by the determination circuit (29) and the alarm device is activated. (1
6).

During normal operation, the residual magnetization of the bolt (20) and the dummy bolt (26) are the same because they are saturated magnetized, and there is no difference in magnetic flux. On the other hand, in the event of a field ground fault, a ground current flows through the detection excitation winding (12), the magnetic flux created by the coil (19) is added to the residual magnetization, and the magnetic flux of the bolt (20) becomes the magnetic flux of the dummy bolt (26). Become bigger. This is detected by the detection part (14)
The comparator circuit (28) compares the signals resulting from both magnetic fluxes, and the determination circuit (29) determines the difference between the two, thereby operating the alarm device (16). Therefore, even if the residual magnetization changes over time, the bolt (20) and the dummy bolt (26
) changes are the same, so there is no problem.

FIG. 8 shows a fourth embodiment, in which a dummy winding (30) wound with the same winding as the detection excitation winding (12) is used in place of the dummy bolt (26) in FIG. It is something. By applying a current to the dummy winding (30) after attaching the dummy winding (30) to the ring (l8), the dummy bolt (26
) can be saturated magnetized.

In this case, the magnetic saturation level of the dummy bolt (26) and the bolt (20) can be easily managed by connecting the dummy winding (28) and the detection excitation winding (12) in series or in parallel to allow current to flow at the same time. becomes.

〔Effect of the invention〕

As described above, according to the present invention, in a brushless rotating electrical machine, the field ground fault detection device compares the generated magnetic flux of the excitation winding with the residual magnetic flux, and when the generated magnetic flux exceeds the residual magnetic flux, the signal processing circuit generates a signal. Since this is provided, there is an excellent effect in that ground faults in the field circuit can be reliably detected in a non-contact manner regardless of the magnetic history of the members.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing a non-contact type field ground fault detection device in an embodiment of the brushless rotating electric machine of the present invention, and FIG.
The figure is a front view showing the structure of the detection device in Fig. 1, Fig. 3 is a longitudinal sectional view taken along line A-A in Fig. 2, Fig. 4 is a circuit diagram showing the signal processing circuit in Fig. 1, FIG. 5 is a circuit diagram showing the signal processing circuit of the second embodiment, FIG. 6 is a vertical sectional view showing the detection device of the third embodiment, and FIG. 7 is a circuit diagram showing the signal processing circuit of the third embodiment. The circuit diagram and FIG. 8 are longitudinal sectional views showing the detection device of the fourth embodiment. 12...Detection excitation winding 14...Detection section 15...Signal processing circuit 16...Alarm device 18...Link 19...
... Coil 20 ... Volt 21 ... Detection element 22 ... Iron core 23 ... Bias setting circuit 24 ...
Comparison circuit 25...Memory circuit 26...Dummy port 2
8... Comparison circuit 29... Judgment circuit 30... Dummy gland ring agent patent attorney Kazuo Inoue

Claims (5)

[Claims] 1. A non-contact type consisting of a member that fixes a detection excitation winding to the outer periphery of a rotating part to form a magnetic pole, and a detection part that is disposed on a fixed part opposite to this member and magnetically couples with the detection excitation winding. In a brushless rotating electric machine equipped with a field ground fault detection device, the field ground fault detection device compares the generated magnetic flux of the detection excitation winding with the residual magnetic flux of the member, and sends a signal when the generated magnetic flux exceeds the residual magnetic flux. A brushless rotating electrical machine characterized by being provided with a signal processing circuit that generates. 2. 2. The brushless rotating electric machine according to claim 1, wherein the signal processing circuit includes a residual magnetic flux bias setting circuit and a comparison circuit for comparing the residual magnetic flux and the generated magnetic flux. 3. The brushless motor according to claim 1, wherein the signal processing circuit is provided with an initial value storage circuit that stores the normal magnetic flux value of the member as an initial value, and a comparison circuit that compares the normal magnetic flux with the generated magnetic flux. Rotating electric machine. 4. The present invention is characterized in that a detection section is installed in the rotating section and detects the magnetic flux of a residually magnetized dummy member and a member of the detection excitation winding, and a signal processing circuit is provided for comparing the residual magnetic flux and the generated magnetic flux. A brushless rotating electric machine according to claim 1. 5. 5. The brushless rotating electric machine according to claim 4, wherein the dummy member is wound with a dummy winding that is the same as the detection excitation winding.