JPH06269151A - Brushless synchronous generator - Google Patents

Abstract

PURPOSE:To obtain a brushless synchronous generator, which does not require a brush constitution for DC excitation and the constitution for a special exciting circuit and can easily performe the control of the output voltage of the generator. CONSTITUTION:Capacitors C are connected between the terminal armature windings 3 of three-phase star connection. Three-phase auxiliary windings 4 and a thyristor SCR are connected in series in an auxiliary circuit 5. A stator side 1 is constituted of these parts. Rotor windings 6 are provided and connected in three-phase star interconnection. Diodes D2 and D3 are connected between the lines of the rotor windings 6 in parallel. A rotor side 2 is constituted of these parts. This motor comprises the stator side 1 and the rotor side 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-excited synchronous generator, which does not require an exciting current from the outside through a slip ring or the like, and is capable of handling a load without providing a special exciting circuit. Regarding synchronous generators.

[0002]

2. Description of the Related Art Generally, there is self-excited power generation by a capacitive load of a non-excitation synchronous generator in which a capacitor is connected to a stator of a synchronous generator as a load. This example is shown in FIG. In FIG. 1, when the synchronous generator 3 is composed of a non-excited rotor 1 and a stator 2 to which a capacitor C is connected via a switch S between output terminals a, b and c, even if the rotor is non-excited. However, when the rotor is rotated, an extremely low electromotive force is induced in the armature winding of the stator due to the residual magnetism of the rotor. Terminal voltage V with respect to armature lead current I at this time
The relationship is as shown by the straight line A'in FIG. However, this is the case where saturation is ignored, and saturation of the magnetic path occurs in an actual generator, so the VI characteristic of the generator is the saturation curve indicated by A.

Further, self-excited power generation when the capacitor C is connected as a load will be described. Between the terminal voltage V of the capacitor C connected as a load and its charging current I,
The following relationship is clear when the frequency is f.

[0004]

## EQU1 ## I = 2.pi.fcV This relationship is shown in FIG.
In self-excited power generation, electromotive force due to residual magnetism causes capacitor C to
A leading current of 0 ° flows, which causes the armature terminal voltage V of the stator to rise, and the charging current to increase correspondingly, and the voltage and current at the intersection P between the saturation curve A and the charging characteristic curve B repeat. Will be stable and continue to generate electricity.

[0005]

When a load is connected to the output terminals a, b and c of the generator, a voltage drop occurs.
This voltage drop increases as the load increases and the load power factor decreases. Here it is necessary to compensate for this voltage drop.
This is because self-excited power generation is performed by the remanent magnetism of the rotor, and it cannot withstand normal use as it is. Generally, a synchronous generator has magnetic poles to create a magnetic field flux like a DC machine. Although a permanent magnet may be used for this magnetic pole in a small synchronous generator, it is common to perform DC excitation, and another exciter is required for this DC excitation. There are various excitation devices such as those that are directly supplied from a DC power supply, those that are supplied with alternating current for rectification, and those that are supplied with direct current by an AC power supply and a rectifier. In addition, there is a drawback in that maintenance is not easy because it requires a structure in which a current is passed through the rotor via a brush in order to form a magnetic field in the rotor.

[0006]

In order to solve the above-mentioned drawbacks of the prior art, a rotor core is provided with a three-phase rotor winding to perform a three-phase star connection, and two rotor windings are connected. A rotor having a rectifying element connected between the windings and a stator core provided around the rotor core so as to face the rotor core, and the three-phase star-connected armature winding is wound around the stator. A stator having a capacitance connected between the output terminals and windings are provided in the same phase of the armature winding of the stator, and are connected in series so that the total voltage induced in the winding does not become zero. A synchronous generator was constituted by an auxiliary winding and an auxiliary circuit in which the terminals of the auxiliary winding were connected via a thyristor element.

[0007]

According to the synchronous generator of the present invention, a rotor in which a diode is connected between two lines of a three-phase star-connected rotor winding, and a three-phase star-connected armature winding and its output terminal are connected. An auxiliary winding is provided in the same phase of the stator and the armature winding of the stator to which an electrostatic capacity is connected, and the auxiliary winding is connected in series so that the total voltage induced in the auxiliary winding does not become zero, and its terminal is connected to a thyristor It is configured with an auxiliary circuit connected via the.

In the above structure, when the rotor is rotationally driven by another electric motor or a prime mover, a voltage is induced in the armature winding due to the residual magnetism of the rotor. This voltage causes a 90 ° advance current to flow in the capacitance, and this advance current increases the armature terminal voltage V of the stator, and the charging current accordingly increases. Grows. Eventually, the voltage and current at the intersection of the saturation curve of the armature winding and the charging characteristic of the capacitance settle down. Up to now, the operation is the same as the conventional self-excited synchronous generator.

In the present invention, the stator is provided with auxiliary windings in addition to the armature windings. A voltage is induced in this auxiliary winding by a three-phase armature current due to the voltage induced in the armature winding. This voltage causes a rectified current to flow in the auxiliary winding of the auxiliary circuit via the thyristor element of the circuit. This rectified current contains a direct current component and an alternating current component.

First, the direct current component creates a static magnetic field, and the rotor induces a voltage by this static magnetic field. Since the rotor has a rectifying element between the lines, the rectifying element rectifies the rotor winding. A current flows to form a magnetic pole, which acts to increase the induced voltage in the armature winding of the stator.

On the other hand, the AC component has a positive phase component and a negative phase component.
First, the positive phase component acts to drop the voltage due to the synchronous impedance of the generator, but the negative phase component creates a magnetic field reverse to the rotating magnetic field of the rotor, and this rotating magnetic field induces a voltage in the rotor. The rectifying element provided between the lines of the rotor causes a rectifying current to flow, and acts to strengthen the magnetic poles of the rotor. The stronger the rotor magnetic field, the greater the induced voltage in the stator armature windings.

If a thyristor element is provided in the auxiliary circuit, it is possible to control the rectified current by the firing angle of the thyristor element, which controls the output voltage from the output terminal of the armature winding. It becomes possible.

As described above, the brushless construction of the self-exciting type synchronous generator is provided with the auxiliary circuit in which the auxiliary winding is wound around the stator and connected by the thyristor element, and the commutation is performed between the lines of the rotor winding. It can be realized with a simple configuration of providing an element.

[0014]

Embodiment An embodiment of the present invention will be described with reference to FIG. Figure 3
In the brushless synchronous generator of the present invention, only the winding parts of the stator and the rotor are extracted as shown in FIG.
First, reference numeral 1 indicates the stator side of the synchronous generator, and reference numeral 2 also indicates the rotor side.

First, on the stator side 1, a star connection armature winding 3 is provided on a stator core (omitted). A capacitor C, which is a capacitive load, is provided between the output terminals a, b, and c of the armature winding 3. Also, the armature winding 3
Auxiliary windings 4 are provided on the same phase of each thyristor SCR
And is connected in series via and serves as an auxiliary circuit 5. The auxiliary windings 4 connected in series of the auxiliary circuit 5 are connected in series so that the sum of the voltages induced in the auxiliary windings 4 by the action of the armature windings 3 of the same phase does not always become zero.

On the other hand, on the rotor side 2, a rotor winding 6 is provided on a rotor core (not shown), the rotor winding 6 is connected to a star, and the rotor winding 6 is connected in parallel between the lines. Diodes D ₂ and D ₃ are connected as particle size control elements.

For convenience of explanation, the voltage induced in each winding is defined as follows. Let E _{1 be} the voltage induced in the armature winding 3 of the stator, and E ₂ be the voltage induced in the auxiliary winding 4 by the voltage of the armature winding. Further, the voltage induced in the rotor winding 6 by the voltage E ₂ of the auxiliary winding 6 is e.

In the synchronous motor of the present invention having the above-described structure, the rotor side 2 is driven to rotate by another electric motor or a prime mover to generate electricity.

When the rotor side 2 is rotationally driven, a slight voltage is induced in the armature winding 3 due to the residual magnetism of the rotor. This voltage V causes the capacitor C, which is a capacitive load, to rotate 90 °.
Of the stator armature voltage V increases due to this leading current, and the charging current also increases accordingly, so that the voltage V of the armature winding 3 increases, and finally the armature winding 3 increases. It will settle at the intersection point P (see FIG. 2) between the saturation curve of the subsidiary winding and the charging characteristic of the electrostatic capacitance.

The feature of the present invention is that the auxiliary winding 4 is provided in the same phase as the armature winding 3 of the stator. The auxiliary winding 4 is connected in series so that the total voltage induced in the auxiliary windings 4 of the respective phases does not become zero, and the terminals of the connected auxiliary windings are connected via a thyristor SCR. The feature is that it is set to 5.

The auxiliary winding 4 includes the above-mentioned armature winding 3
The voltage E ₂ is induced by the armature current flowing due to the voltage V induced at the initial stage of startup. This voltage E ₂ causes the auxiliary winding 4 of the auxiliary circuit 5 to pass through the thyristor SCR of the circuit 5.
The rectified current will flow through the. This rectified current includes a direct current component and an alternating current component. The direct current and the alternating current will be separately described below.

First, the direct current component of the rectified current creates a static magnetic field on the stator side 1, and this static magnetic field interlinks with the rotor winding 6 of the rotor to be driven to rotate, so that the auxiliary circuit 5 is stationary. The voltage e due to the magnetic field will be induced. Since the diodes D ₂ and D ₃ are provided between the lines of the rotor winding 6, the current due to this voltage e is rectified, and as a result, the rectified current flows through the rotor winding 6 and the rotor The magnetic pole will be formed on the. The magnetic poles formed on this rotor induce a voltage to the stator, and in addition to the voltage V of the stator generated at the initial stage of startup, the induced voltage E _{1 of the} entire armature winding 3 of the stator is further increased. It works like this. In this way, when the induced voltage E ₁ of the armature winding 3 increases, the voltage E ₂ of the auxiliary winding 4 induced by it also increases,
By repeating this action, the armature voltage E ₁ generates practicable electric power.

There is a positive-phase component and a negative-phase component of the alternating current component of one of the rectified currents. First, the positive phase component acts to drop the voltage due to the synchronous impedance of the generator. Since the antiphase component creates a magnetic field that rotates in the opposite direction to the rotating magnetic field of the rotor, the rotor winding 6 interlinks with the magnetic field that rotates in the opposite direction, and acts to induce a voltage in the rotor. In the rotor, the rectified current is caused to flow by inducing a voltage also by the reverse phase component of the AC component of the rectified current by the auxiliary circuit 5, and acts to strengthen the field pole of the rotor.

When the field of the rotor is strengthened by the direct-current component and the alternating-phase component of the alternating current of the auxiliary circuit 5 as described above, the induced voltage E ₁ of the armature winding 3 of the stator is further increased.

By the way, the auxiliary winding 4 of the above-mentioned auxiliary circuit 5
When the auxiliary winding 4 is connected so that the total of the voltages induced in the windings 4 does not become zero, the armature winding 3 is affected by the AC component of the rectified current flowing in the auxiliary winding 4. The effect of will disappear. That is, looking at one of the alternating current components of the rectified current flowing through the thyristor SCR in FIG. 3, assuming that this alternating current component is i, i flows as shown in FIG. Assuming that the alternating current i flowing in the exciting winding 4 causes the compensating current i ′ to flow in the main winding 3 as described above, at the neutral point 0, Kirchhoff's current law is

[0026]

[Equation 2] i ≠ 2i, which does not hold. Therefore, the compensating current i'of the AC component i flowing in the exciting winding 4 does not flow in the main winding 3. That is, there is no interference due to the alternating current between the main winding 3 and the excitation winding 4. As a result, excitation winding 4
Has a large exciting inductance and acts so that the alternating current component i flows through the virtual exciting inductance.

By the way, the thyristor SCR of the auxiliary circuit 5
Controls the firing angle. The control is by controlling the rectified current flowing through the auxiliary circuit 5,
The voltage e induced in the rotor winding will be controlled. As a result, the field of the rotor can be controlled brushlessly,
It is possible to control the output of the generator, that is, the induced voltage of the armature winding 3.

[0028]

As described above, according to the present invention, the auxiliary winding is provided on the stator, and the auxiliary circuit for controlling the current induced by the thyristor is provided between the wires of the rotor winding. By adding a simple winding to the stator, which connects a diode, and an additional combination of common control elements, a DC power supply is not required, an excitation generator is not required, and a slip ring that is troublesome for maintenance, etc. Also omitted,
It is possible to provide a simple brushless self-excited synchronous motor.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing self-excited power generation by a capacitive load of a non-excitation synchronous generator.

FIG. 2 is a diagram showing a saturation curve of an armature in a capacitive load and a charging characteristic of the capacitive load.

FIG. 3 is a circuit diagram in which a winding portion of the brushless synchronous generator of the present invention is extracted.

FIG. 4 is a diagram showing only the winding portion of the stator, which shows the alternating current component of the auxiliary circuit and the compensation current of the armature winding.

[Explanation of symbols]

1 Stator Side 2 Rotor Side 3 Armature Winding 4 Auxiliary Winding 5 Auxiliary Circuit 6 Rotor Winding SCR Thyristor D ₂ Diode D ₃ Diode

Claims (1)

[Claims] 1. A rotor having three-phase rotor windings provided on a rotor core for three-phase star connection and a rectifying element connected between two lines of the rotor winding, and the rotor core. A stator having stator cores arranged facing each other, the stator core being wound with an armature winding having a three-phase star connection, and having a capacitance connected between its output terminals; Each of the armature windings has a winding in the same phase and is connected in series to form an auxiliary winding so that the sum of the voltages induced in the winding does not become zero, and the terminals of the auxiliary winding are connected via thyristor elements. A brushless synchronous generator characterized by being configured with the auxiliary circuit described above.