JPS5821347Y2 - Brushless synchronous machine field monitoring device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device that measures the amount of field excitation of a brushless synchronous machine and monitors abnormalities in the field section.

Many proposals have been made in the past regarding the excitation amount of the rotating field of a brushless synchronous machine.

Taking temperature measurement of field windings as an example, the 1M telemetry method is well known.

This method either directly detects the temperature of the field winding, or detects the field voltage and current, converts the signal with an FM transmitter installed on a rotating body, and transmits the signal, and a receiving antenna installed on the fixed side. The temperature is measured by receiving the temperature on the fixed side, calculates the resistance value on the fixed side, and displays the temperature.

In addition to these methods, various methods have been proposed for measuring field current and field voltage.

Next, FIG. 1 shows a principle diagram of a brushless excitation system having a rotary rectifier.

1 is a synchronous machine, 2 is an armature of the synchronous machine, 3 is a rotating field of the synchronous machine, and 4 is a rotor directly connected to the synchronous machine and the brushless exciter.

5 is a rotating rectifier, 6 is an AC exciter, and the stator field 7 is
and a rotating armature 8.

Reference numeral 9 denotes a sub-exciter, which is composed of a rotating field 10 made of a permanent magnet and an armature 11 of a stator.

12 is an automatic voltage regulator that adjusts the field current of the AC exciter 6; 13 is the armature 8 of the AC exciter 6 and the rotary rectifier 5;
and a plurality of connecting conductors.

FIG. 2 is an explanatory diagram showing an outline of the rotor portion of the AC exciter 6 shown in FIG.

The armature 8 has two parallel circuits for each phase by wire connection, and is fastened to each phase by a phase cylinder 14.

The rectifier 5 has a three-phase full-wave connection, and has a 1s-3P-6A (
One series of diodes 5a for each phase is made into three parallel circuits.
, - side, total of 6 arms).

The connecting conductor 13 is connected to the phase ring 14 for each phase and the diode 5a2 circuit (+ side and - side), and is configured with three conductors for each phase.

The details of the rectifier are omitted in FIG. 2, but a fuse for protection against force ζ is connected in series to each diode 5a.

In the device configured in this manner, when the rotor 4 is rotated and an excitation current is passed through the field 7, a three-phase alternating current is generated in the armature 8.

This alternating current gold is rectified by the rotating rectifier 5 and supplied to the rotating field 3 of the synchronous machine.

Figure 3 shows the relationship between the armature of an AC exciter and the magnetic conductor.

The field 7 has a plurality of magnetic poles 15, and in the armature 8, an armature coil 16 having a certain phase band is connected at one end to the phase ring 14 and at the other end to the neutral ring 1T.

The number of connection conductors 13 is generally determined by the configuration of the rectifier circuit, etc., and is distributed on the same-shaped child axis in the correct shape.

FIG. 4 shows a cross-sectional view of an example of the arrangement of the connecting conductors 13.

A non-magnetic ring 19 is shrink-fitted to the rotor shaft 18.

The connecting conductors 13 are arranged, for example, as shown in the figure, with an insulating member 20 interposed therebetween, and are fixed with a fixing band 21 such as an epoxy glass band.

The energization of the armature coil is determined by the relationship between the poles and the phase bands.

The angle A between the center of the phase band and the connecting conductor 13 (see Figure 3) depends on the number of poles, armature coil winding method, phase order, rotation method, number of phases, presence or absence of a phase ring, number of connecting conductors and arrangement method, etc. It can be decided.

In the brushless synchronous machine configured as described above, the current in the field 3 has been conventionally measured by, for example, installing a ball element between the magnetic poles of an AC exciter and detecting a magnetic flux proportional to the armature current. It is being

On the other hand, the field voltage is measured by connecting the voltage detection coil 23 to the + and - sides of the DC connection conductor 22 through the resistor 24, as shown in Fig. 5, and using the voltage detection installed on the external fixed side. A method of measuring with the secondary coil 25 has been considered.

In this method, a current proportional to the voltage flows through the secondary coil 23, and the secondary coil 25 detects magnetic flux based on the current.

However, this traditional method has many drawbacks,
It was hardly put to practical use.

FM telemetry methods, although practical, are very expensive.

The current measurement method is a method that picks up magnetic flux, which is relatively simple and has been used, but it only measures current and cannot measure temperature.

Voltage measurement methods tend to cause problems because components are mounted on a rotating body that rotates at high speed, and a circuit is installed between the DC + and - side connecting conductors, and the current is constantly shunted.
There were many problems such as the loss of parts.

For this reason, temperature measurement has been carried out by measuring current and calculating based on that value, which has low accuracy and has limitations in detecting abnormal phenomena.

This invention was made in order to eliminate the drawbacks of the conventional devices as described above, and it is possible to control the excitation quantities of a brushless synchronous machine (for example, changes in field resistance, that is, changes in field temperature) using a simple device. The present invention provides an apparatus for detecting, measuring, and monitoring a field part.

In other words, in principle, the stain current is detected by the electromagnetic induction effect of the excitation current, and the electrical quantities and temperature of the field are measured and monitored, thereby detecting abnormalities in the field. It is something that can be detected.

An apparatus according to an embodiment of this invention is shown in FIG.

The first detection element 26 for detecting the alternating current from the armature 8 of the same type may be installed between the magnetic poles of the stator of the alternating current exciter 6, but as a more accurate method, here the connecting conductor 13 They are installed on the fixed side, facing each other across an air gap.

This first sensing element 26 is an I-shaped core with a sensing coil wound around it, and is usually a combination of multiple pairs of elements to pick up the magnetic flux generated in proportion to the magnitude of the current in the connecting conductor 13, and to generate AC induced Gives a signal as a voltage.

The pair of detection elements 26, 26 are buttoned at a predetermined distance from each other, for example, the in-phase pole spacing for each connection conductor 13 is l.
/2 distance apart.

The second detection element 27 for detecting direct current may be a concave core with a detection coil wound around it, and is installed on the fixed side facing the connecting conductor 22 of the direct current across an air gap, and detects the flowing direct current. It picks up magnetic flux proportional to the magnitude of the current and outputs a signal as an AC induced voltage.

That is, the signals of both detection elements 26 and 27 are proportional to the AC and DC current values before and after the rotary rectifier 5, respectively.

When the resistance value of the field coil 3 is constant, the relationship between the two signal amounts is proportional, but in reality, the relationship between current and voltage changes with υ due to a change in resistance due to a rise in the temperature of the field coil 3. As a result, the overlap angle during commutation of the rectifier circuit varies, causing a deviation from the linear characteristic.

This deviation is caused by a change in the ratio of the amount of current flowing through the rotating body, a change in the energization state of the alternating current, and a change in the position of the center of the armature coil 16 phase band and pole center in FIG. A proportional signal amount from .27 produces a magnified change as shown in FIG.

Iac is the amount of alternating current signal output from the detection element 26, and Ia
c is the amount of DC signal output from the detection element 27.

This change can be confirmed in advance through calculations and tests, and if during actual operation the amount of change deviates from the expected value and an abnormality occurs, the temperature of the field coil 3 is abnormally high and the current This indicates an abnormal phenomenon such as the voltage becoming high even though the voltage is constant.

The proportional amount detection circuit 28 detects how this proportional signal changes in relation to the change in the signal amount of the first detection element or the second detection element.
The amount of deviation from the set value or a signal indicating the deviation is displayed on a display device (not shown) such as an indicator or an alarm device.

As for the signal characteristics, even if you take the peak value or the average value of each detection element 26, 27 signal, the proportional amount does not change, so either is fine.The theory is that in the end, it is sufficient to capture the change in the proportional amount of both. be.

For example, if Iac/Idc is too large, it can be determined that there is an abnormality in temperature; if Iac/Idc is too small, it can be determined that a short circuit has occurred.

From the relationship between the signal amount of one detection element 26 or 21 and this proportional amount, the relationship between the load current and the temperature of the field coil or the field voltage can be easily and accurately determined, and normality and abnormality can be monitored. As well as a protection device, the field current,
It is also possible to use it as a measuring device for various quantities such as voltage.

In the above embodiment, an abnormal phenomenon of the field 3 has been explained. Even in the event of a disconnection or short circuit,
It goes without saying that any change in the proportional amount can detect abnormalities.

In this way, various conditions of the field section can be monitored.

However, if the fluctuation of the angle of overlap during a transient phenomenon, which is a rapidly changing state, is a problem, it is naturally correlated with the field current of the AC exciter 6, so It is sufficient to provide a limiting circuit.

That is, when the field current of the AC exciter 6 changes,
According to this invention, a circuit (not shown) that outputs the output signal of the proportional amount detection circuit 28 for a certain period of time is incorporated into the proportional amount detection circuit 28. It has a simple configuration in which detection elements are installed corresponding to the connection conductors on the AC side and DC side of the rotary rectifier, and no special equipment is required for the rotating body, and proportional signal processing is performed. , it becomes possible to detect abnormalities in brushless synchronous machines and measure various field quantities, and it is possible to obtain a highly reliable and inexpensive monitoring device.

[Brief explanation of drawings]

Figure 1 is a principle diagram of a brushless exciter for a synchronous machine, Figure 2 is a diagram showing the connection conductor between the armature of the AC exciter in Figure 1 and the rotary rectifier, and Figure 3 is a schematic explanation of the rotor. A diagram showing the relationship between the armature coil in Figure 2 and the connecting conductor coming out from it,
Figure 4 is a cross-sectional front view of the connecting conductor portion of the rotor in Figure 2;
FIG. 5 is a principle diagram of a conventional field voltage detection device, FIG. 6 is a configuration diagram of a field monitoring device according to an embodiment of this invention, and FIG.
The figure is a curve diagram showing the relationship between the signal amounts of both detection elements in FIG. 6. 1... Same machine, 3... Rotating field of synchronous machine, 4... Rotor, 5... Rotating rectifier, 6... ... AC exciter, 1... Field,
8... Armature, 13... Connection conductor, 22
....-Tension wire conductor, 26...Detection element, 27
...Detection element, 28...Proportional amount detection circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] In a brushless synchronous machine in which the output of an AC exciter is rectified by a rotary rectifier and added to a rotating field for excitation, the armature of the AC exciter and the rotary rectifier are distributed over a rotating body of a rotor. a plurality of first connection conductors that connect and conduct AC current; a second connection conductor that connects the rotary rectifier and the rotating field and conducts direct current; a second connection conductor that faces and is fixed to the first connection conductor across an air gap; a first detection element arranged on the side and detects the current; a second detection element arranged on the opposite side with an air gap to the second connection conductor and detects the current; A field monitoring device for a brushless synchronous machine, which includes a proportional amount detection circuit that calculates a proportional amount from each signal amount from the first and second detection elements and outputs a signal when the amount exceeds a predetermined set value.