JPH09215395A - Self-excited three-phase ac generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-excited three-phase AC generator which facilitates the excitation which can generate a power endurable to a heavy load with a simple construction. SOLUTION: A field winding Fg, generator windings of a three-phase structure, a first excitation winding A which has a winding pitch for generating an output whose main component is a fundamental wave and which is provided on at least one of the generator windings so as to generate an output having an electrical angle of 90 deg. from the output of the generator winding, a second excitation winding B which has a winding pitch for generating an output whose main component is the third harmonic of the fundamental wave and which is so provided as to generate an output having an electrical angle of 90 deg. from the output of the generator winding and as to correspond to the first excitation winding B and a synthesizing rectifying means which generates the synthesized and rectified output of the fundamental wave output of the first excitation winding A and the third harmonic wave output of the second excitation winding B and supplies the synthesized and rectified output to the field winding Fg are provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has an excitation winding,
Self-excitation type 3 that supplies the output of this excitation winding to the field winding
The present invention relates to a phase-alternating current generator, and more particularly to an excitation generator configured so as not to be affected by a load current.

[0002]

2. Description of the Related Art Conventionally, the excitation means of a small AC generator for performing such excitation is disclosed in, for example, JP-A-55-43905.
There is one as shown in Japanese Patent Publication No. As shown in FIG. 5, a tap is provided in one phase of the three-phase power generation winding, a part of the power generation output is taken out, rectified in the excitation circuit EN, and then applied to the field winding Fg. .

The generator having such a structure has a shunt winding characteristic. As a result of this shunt winding characteristic, when the load is heavy, such as when the motor is used as a load, the output of the motor is insufficient and the motor output is insufficient. There is a problem that it cannot start.

Therefore, as shown in FIG. 6, an exciting winding is formed which is so-called open-delta connected and is provided with a tap for taking out one-phase output. The outputs of the exciting windings are combined / combined. An AC generator has been provided which is rectified and provided as an excitation output to the field winding Fg.

[0005]

However, according to such a configuration, since the three-phase excitation winding is configured, the configuration of the generator is complicated, and the cost is high even though it is a small machine which is strongly required to reduce the cost. become.

The present invention has been made in consideration of the above points, and provides a self-excitation type AC generator which has a simple structure and is capable of generating a power generation output capable of withstanding a heavy load. The purpose is to

[0007]

In order to achieve the above object, the present invention provides a field winding, a power generating winding having a three-phase structure, and an output mainly composed of a fundamental wave. Has a large winding pitch and has an electrical angle of 9 with respect to the output of the generator winding.
A first excitation winding provided in at least one of the power generation windings so as to generate an output having a phase difference of 0 degree, and a winding for generating an output mainly composed of a third harmonic of the fundamental wave. It has a line pitch and has an electrical angle of 9 with respect to the output of the generator winding.
A second excitation winding provided corresponding to the first excitation winding so as to generate an output having a phase difference of 0 degree, a fundamental wave output of the first excitation winding, and the second excitation winding. 3. A self-excited three-phase AC generator, comprising: a combined rectification means for forming a combined rectified output with the third harmonic output of the above, and providing the combined rectified output to the field winding. The combined rectification means in the self-excited AC generator according to Item 1, combines the output of the first excitation winding and the output of the second excitation winding with an AC combination circuit and an output of this AC combination circuit. A self-excited three-phase alternating current generator having a rectifying circuit for rectifying, and the combined rectifying means in the self-excited three-phase alternating current generator according to claim 1, wherein: A first rectifier circuit for rectifying the output, and a second rectifier for rectifying the output of the second excitation winding And road, the first and the self-excited three-phase AC generator and a DC combining circuit for combining the respective rectified output of the second rectifier circuit and provides a.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a basic connection state of a generator according to the present invention. That is, U, V, W in FIG. 1 are power generation output terminals of the three-phase AC generator according to the present invention, and star-connected three-phase power generation windings are connected to each of these terminals U, V, W. ing.

Then, the two exciting windings A, A, are arranged so as to produce an output delayed by an electrical angle of 90 degrees with respect to the output of the U-phase winding.
B is wound. Of these, the excitation winding A is wound at a winding pitch that generates an excitation output having the same frequency as the power generation winding, that is, the fundamental wave frequency, and the other excitation winding B is wound.
Are wound with a winding pitch that generates the third harmonic of the fundamental wave. Here, regarding the point that the excitation winding is arranged at a position of an electrical angle of 90 ° with respect to the phase winding, this electrical angle is selected to be 90 ° ± Δθ and a component in phase with the induced voltage of the phase winding is set to a predetermined amount. Including only a little more aggressive introduction.

The outputs of the excitation windings A and B are combined / rectified by the excitation circuit EN and then given to the field winding Fg as an excitation output.

Here, although the fundamental wave component generated in the excitation winding A has a larger output than the harmonic component, it is affected by the load current output from the generator winding, while the excitation winding A has a larger output. The third harmonic component generated on the line B has a property that it is not so affected. Therefore, when the fundamental wave and the third harmonic are combined, it is possible to form an exciting output that has a large output and is not significantly affected by the load current.

The synthesis of the fundamental wave and the third harmonic can be performed in an alternating current stage, that is, the outputs of both excitation windings A and B can be synthesized as alternating current, or can be performed in a direct current stage after rectification. .

FIG. 2 shows an embodiment in which both outputs of the excitation windings A and B are combined in the AC stage and then rectified and given to the field winding Fg. For this purpose, the excitation windings A and B are connected in series so that their outputs are combined, and the combined AC output is used as the excitation circuit EN.
Is applied to the field rectifier REC for rectification and then applied to the field winding Fg.

Waveforms at various parts during the operation of this embodiment will be described later with reference to FIG.

FIG. 3 shows an embodiment in which the respective outputs of the excitation windings A and B are separately rectified by the two rectifiers REC of the excitation circuit EN, and the rectified outputs are given in parallel to the field winding Fg. It is shown. For this purpose, the excitation windings A and B are separately connected to the rectifier REC.
Are connected in parallel and are connected to the field winding Fg.

Waveforms at various parts during the operation of this embodiment will be described later with reference to FIG.

FIG. 4 shows voltage waveforms at various parts of the circuit in the two embodiments shown in FIGS. 2 and 3.
In addition, FIG. 4 includes nine waveform diagrams consisting of three columns (a), (b) and (c) in the vertical direction and three columns (1), (2) and (3) in the horizontal direction. ing.

In (a) and (b) in the vertical direction, the voltage waveforms of the excitation windings A and B are indicated by thin lines with reference numerals A and B, respectively, and their combined voltage waveforms are indicated by solid lines. Has been done. Then, in (c), a waveform obtained by rectifying the combined voltage waveform in (a) by both waves is shown by a solid line.

On the other hand, (1) in the horizontal direction shows the case where the output of the excitation winding A and the output of the same B are in phase, and the same (2) shows the output of the excitation winding A with respect to the output of the same B. Similarly, (3) shows the case where the output of the excitation winding A is delayed by 90 degrees with respect to the output of the same winding B.

The following two characteristic items are shown in this waveform diagram.

First, when these voltage waveforms are viewed in the vertical direction, the characteristic feature of the comparison between (b) and (c) is that, as shown in (b), If both outputs of lines A and B are rectified to direct current and then combined,
This means that both the peak value of the voltage and the pulsation width are smaller than in the case of rectifying after synthesizing in the AC stage as shown in (c).

Next, what is characteristic when viewed along the lateral direction is the waveform in the case of synthesis after rectification, (b)
Comparing (1) and (2) and (3) belonging to the stage,
In (1) and (2), there is a zero voltage point,
In (3), there is no voltage zero point. This is because there is no voltage zero point in the output after rectification when the phase difference between the outputs of both excitation windings A and B is 90 degrees, but when both outputs are in phase and there is a phase difference of 180 degrees. Means that a voltage zero point occurs.

From these two points, when it is desired to obtain an excitation output having a small voltage value, it is preferable to rectify the outputs of the excitation windings A and B having the structure shown in FIG. 3 and then combine them. I understand. As a result, a rectifier with a small reverse breakdown voltage can be used. On the contrary, when it is desired to obtain an excitation output having a large voltage value, it is preferable to perform rectification after synthesizing in the AC stage having the configuration shown in FIG. In this case, the high voltage allows a large current to flow through the field winding.

[0024]

As described above, according to the present invention, the first excitation winding that produces a fundamental wave output having an electrical angle of 90 degrees and the third harmonic output that also produces an electrical angle of 90 degrees with respect to the generator winding output. Since two exciting windings are provided and the outputs of both exciting windings are combined / rectified and the exciting current is passed through the field winding, the exciting current including the third harmonic that is hardly affected by the load current is generated. It can be supplied, and a sufficient excitation output can be formed even though it is a single phase and does not complicate the configuration of the generator. Therefore, a small size 3 that can withstand heavy loads and has high reliability
A phase alternator can be provided.

[Brief description of drawings]

FIG. 1 is a connection diagram showing a basic connection state of a generator according to the present invention.

FIG. 2 is a connection diagram showing a connection state of the first embodiment of the present invention.

FIG. 3 is a connection diagram showing a connection state of a second embodiment of the present invention.

FIG. 4 is a waveform diagram showing voltage waveforms at various parts of the circuit in the embodiments of FIGS. 2 and 3.

FIG. 5 is a connection diagram showing a connection state of a conventional three-phase AC generator.

FIG. 6 is a connection diagram showing a connection state of a conventional three-phase AC generator.

[Explanation of symbols] U, V, W Power generation winding terminals A, B Excitation winding EN Excitation circuit Fg Field winding REC Rectifier

Claims (3)

[Claims] 1. A field winding, a three-phase power generation winding, and a winding pitch that produces an output mainly consisting of a fundamental wave, and an electrical angle with respect to the output of the power generation winding. A first excitation winding provided in at least one of the power generation windings so as to generate an output having a phase difference of 90 degrees, and a winding for generating an output mainly including a third harmonic of the fundamental wave. A second excitation winding provided corresponding to the first excitation winding so as to generate an output having a line pitch and having a phase difference of 90 degrees in electrical angle with respect to the output of the power generation winding; , A composite rectification means for forming a composite rectified output of the fundamental wave output of the first excitation winding and the third harmonic output of the second excitation winding and providing the combined rectification output to the field winding. A self-excited three-phase AC generator. 2. The self-excited three-phase AC generator according to claim 1, wherein the synthetic rectifying means synthesizes the output of the first excitation winding and the output of the second excitation winding. A self-excited three-phase AC generator having a rectifying circuit for rectifying the output of the AC synthesizing circuit. 3. The self-excited three-phase alternating-current generator according to claim 1, wherein the combined rectifying unit includes a first rectifying circuit that rectifies an output of the first exciting winding, and a second exciting winding of the second exciting winding. A self-excited three-phase AC generator having a second rectifying circuit for rectifying the output and a DC synthesizing circuit for synthesizing the rectified outputs of the first and second rectifying circuits.