JPH0724930Y2 - Brushless single phase alternator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an improvement of a brushless single-phase AC generator.

[Conventional technology]

Conventionally, a so-called capacitor excitation method has been widely used as a brushless AC generator.

FIG. 7 shows the configuration of this type of brushless AC generator.
In FIG. 7, a rotor core a has a rotor excitation winding b.
Is wound around the rotor field winding b.
Are connected.

On the other hand, an armature winding e and a stator excitation winding f are wound around the stator core d electrically with their phases shifted by 90 °, and a capacitor g is connected to both ends of the stator excitation winding f. ing. h
Indicates a load connected to both ends of the armature winding e.

Next, the power generation action will be described. When the rotor core a rotates, the residual magnetism causes a phase-advancing current to flow in the stator excitation winding f, and the rotor field winding b interlinking with the magnetic flux generated by the phase-advancing current is twice as fast as the synchronous speed. By inducing an AC voltage having a frequency of, and half-wave rectifying the AC voltage by the rectifier c, a field current I _F flows in the rotor field winding b to perform self-excitation. Further, the magnetomotive force of the armature reaction generated by the load current flowing through the armature winding e acts to enhance the magnetic flux due to the field current I _F flowing through the rotor field winding b, and the output by the load. Operates to compensate for the voltage drop.

[Problems to be solved by the device]

However, this type of brushless AC generator has a disadvantage that a large pulse-like drop occurs in the voltage waveform induced in the armature winding e.

That is, FIG. 8A shows an output voltage waveform at no load induced in the armature winding e of this type of brushless AC generator, and FIG. 8B shows a field flowing in the rotor field winding b. but shows the waveform of the current I _F, to half-wave rectification of the voltage induced in the rotor field winding b by the rectifier c, the field current I _F is the FIG. 8 (B) The waveform becomes as shown in FIG. 7 and the drop (point C) causes the drop (point D) in the output voltage waveform as shown in FIG.

Further, the field current I _F depends only on the voltage induced in the rotor field windings b, can not provide sufficient field current to load or inductive load at startup, a large voltage drop and inductive loads There was also a problem that it caused a startup failure.

Furthermore, recently, generators driven by an engine have come into widespread use with a slowdown device that rotates at low speed when there is no load in consideration of noise and fuel consumption. the alternator system, supply of the field current I _F becomes more insufficient,
There are problems such as difficulty in establishing the output voltage. Therefore, the conventional brushless AC generator of this type is actually limited to being applied to a small-capacity machine whose characteristics are relatively unimportant before and after IKVA.

Further, there is a structure in which a slot is provided at a predetermined position on the pole surface of the field pole and a voltage compensation winding is wound around this slot.
As disclosed in Japanese Patent No. 61-161942, this voltage compensating winding does not function at all at no load, and it is necessary to constantly supply a field current from the outside in order to establish a voltage. Since it has a structure that requires a brush, it cannot be used as a brushless AC generator.

In addition, as a brushless AC generator, there is provided a structure in which an inductor salient pole is provided in a portion of the stator core where the main armature winding slot is not provided, and an exciting winding is provided at the field pole pole of the rotor. As disclosed in Japanese Patent Publication No. 61-46149, the voltage compensation capability under load is small, and since it is necessary to keep the iron core in a high magnetic saturation state even when there is no load, there are functional aspects such as an increase in iron loss. There is a problem in efficiency. In addition, there is a problem that the discontinuity of the magnetic path in the stator core caused by the provision of the inductor salient pole adversely affects the output voltage waveform.

The present invention has been made in view of the above problems, and supplies an output voltage having a good sine waveform without a drop in the output voltage waveform, and further, a sufficient field current at the time of starting a load or an inductive load. It is an object of the present invention to provide a brushless single-phase alternating current generator that supplies electricity.

[Means for Solving the Problems]

Means for solving the above problems are shown in FIGS.
Explaining with reference to the drawings, the armature winding 2 and the stator excitation winding 3 are wound in a slot formed on the inner peripheral surface of the stator iron core 1 by electrically shifting the phases by 90 °. A capacitor 4 is connected to both ends of the stator excitation winding 3, and a slot 6 is formed in the pole arc surface 5a of the rotor core 5. The slot 6 is provided with the armature winding 2 and the stator excitation winding 3 and a magnetic field. The rotor excitation winding 7 is wound so as to form a dynamic coupling, and the rotor excitation winding 7 is wound.
A field current obtained by rectifying the AC voltage induced in the armature by a rectifier 8 is provided, and the rotor field winding 9 is wound around the same number of magnetic poles as the armature winding 2. It is a brushless single-phase AC generator equipped with.

[Action]

This invention consists of the above means, and its operation will be described with reference to FIGS. 1 to 3. A rotor connected to the output end of a rectifier 8 formed by bridge-connecting four diodes. The voltage induced in the field winding 9 is applied to the rectifier 8
A field current obtained by half-wave rectification by the diodes D ₁ , D _{2 and} D ₃ , D ₄ forming the above is supplied to the rotor field winding 9. In addition to this, the voltage induced in the rotor excitation winding 7 connected to the AC input terminal of the rectifier 8 is full-wave rectified by the diodes D ₁ , D ₂ , D ₃ , D ₄ forming the rectifier 8. The field current thus obtained is supplied to the rotor field winding 9.

〔Example〕

FIG. 1 is an electric circuit diagram of an embodiment of the present invention, in which a stator has an armature winding 2 and a stator excitation winding 3 in slots (not shown) formed in an inner peripheral surface of a stator core 1. And are electrically wound with their phases shifted substantially by 90 °, and a capacitor 4 is connected to both ends of this stator excitation winding 3.

On the other hand, as shown in FIG. 2, the rotor has a slot 6 formed in the pole arc surface 5a of the rotor core 5, and the slot 6 is magnetically coupled with the armature winding 2 and the stator excitation winding 3. The rotor excitation winding 7 is wound so as to form a coupling as shown in FIG. 3, and the two ends of the rotor excitation winding 7 are integrated with the rotor core 5 by four diodes D. ₁ , D ₂ , D ₃ , D ₄ are connected to the AC input end of a rectifier 8 formed by bridge connection, and the DC output end of the rectifier 8 is a rotor field winding wound around the rotor core 5. It is connected to both ends of the line 9. Reference numeral 10 is a load connected to both ends of the armature winding 2.

In the above configuration, when the rotor core 5 is rotated, a voltage is induced in the stator excitation winding 3 due to the residual magnetism thereof, and the voltage is induced by the action of the capacitors 4 connected to both ends of the stator excitation winding 3. A phase current flows, and an induced voltage is generated in the rotor field winding b9 and the rotor excitation winding 7 that interlink with the magnetic flux created by this phase-advancing current. The alternating voltage induced in the rotor field winding 9 causes the diode D ₁ , which forms the rectifier 8,
D ₂ and D _3, the D ₄ passing half-wave rectified field current I _F. Further, the AC voltage induced in the rotor excitation winding 7 is full-wave rectified by the diodes D ₁ , D ₂ , D ₃ , and D ₄ forming the rectifier 8, and the field current is also supplied from the rotor excitation winding 7. I _F is supplied to the rotor field winding 9 to perform self-excitation.

FIG. 4 (A) shows the output voltage waveform under no load according to the present invention obtained by the experiment, and FIG. 4 (B) shows the waveform of the field current I _F flowing through the rotor field winding 9. Is.

As can be seen from this figure, compared with the conventional example shown in the FIG. 8, the field current I _F is also eliminated to become zero. This is because the field current supplied from the rotor excitation winding 7 to the rotor field winding 9 serves to fill the drop in the field current waveform as shown in FIG. This is because As a result, the drop in the output voltage waveform is eliminated, and it becomes possible to obtain an AC output voltage having a good output voltage waveform.

FIG. 5 is a graph comparing changes in output voltage and field current with changes in load current between this device and the conventional example by experiments. As can be seen from this graph, the increase of the field current accompanying the increase of the load current is larger than that of the conventional example by the fact that the rotor exciting winding 7 is provided in this invention,
Regarding the output voltage, the voltage drop is small and the voltage fluctuation is improved.

FIG. 6 compares the starting performance of this invention with that of the conventional example by experiments using an induction motor as an inductive load. In the figure, (A) and (C) are field current waveforms,
(B) and (D) are output voltage waveforms, (A) and (B) are conventional examples, and (C) and (D) are based on this invention. Point A is the moment of starting the inductive load, and point B is
It is the point at which the rated rotation is reached, and T is the time from startup to the rated rotation. As can be seen from this figure, in the device according to the present invention compared to the conventional example, the field current immediately after starting increases rapidly, so the time T from starting to reaching the rated rotation is short, and the voltage drop at starting is much longer. It can be seen that it is extremely small (see V in FIG. 6).

In this embodiment, the rotor excitation winding 7 is wound between the different poles at the center of the salient poles of the rotor core 5, but the armature winding 2 wound around the stator core 1 and the stator excitation winding 7 are wound. The winding position and the number of slots of the rotor excitation winding 7 are not limited to those in this embodiment, because the magnetic flux may be linked with the magnetic flux generated by the current flowing through the winding 3.

[Effect of device]

The present invention has the following effects due to the configuration described above.

By eliminating the zero point of the field current waveform, it became possible to obtain a good sinusoidal voltage with little distortion in the armature winding.

Since a sufficient field current can be supplied even under load or inductive load, a large voltage drop and start-up failure can be eliminated.

As a single-phase AC generator, it has become possible to use a relatively large capacity of around 5 KVA.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention,
FIG. 1 is an electric circuit diagram thereof, FIG. 2 is a structural diagram of the rotor core thereof, FIG. 3 is a winding mode diagram of the rotor core, and FIG. 4 is an output voltage waveform (A) of the unloaded condition. And FIG. 5 is a graph showing the field current waveform (B), FIG. 5 is a graph showing changes in output voltage and field current with changes in load current in the conventional example and the embodiment of the present invention, and FIG. Field current waveforms (A) and (C) and output voltage waveform (B) at the time of starting an inductive load in Examples (A) and (B) and Examples (C) and (D) of the present invention,
FIG. 7 is a diagram showing (D), FIG. 7 is a configuration diagram of a conventional brushless single-phase AC generator, and FIG. 8 shows an output voltage waveform (A) and a field current waveform (B) at the time of no load in the conventional example. It is the figure shown. 1 ... Stator core, 2 ... Armature winding, 3 ... Stator excitation winding, 4 ... Capacitor, 5 ... Rotor core, 6 ... Slot,
7 ... Rotor excitation winding, 8 ... Rectifier, 9 ... Rotor field winding, 10 ... Load.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. An armature winding and a stator excitation winding are electrically wound 90 ° out of phase with each other in a slot formed on the inner peripheral surface of the stator core, and the stator excitation winding Connect capacitors to both ends, form slots on the polar arc surface of the rotor core,
A rotor exciting winding is wound around this slot so as to form a magnetic coupling with the armature winding and the stator exciting winding, and the AC voltage induced in the rotor exciting winding is rectified by a rectifier to obtain A brushless single-phase AC generator, which is provided with a rotor field winding which is supplied with the generated field current and is wound around the same number of magnetic poles as the armature winding.