JPH0787717A - Brushless synchronous generator - Google Patents

Abstract

(57) [Abstract] [Purpose] Even when driving equipment such as an induction motor where the load current at start-up changes drastically, at this time without providing a large voltage adjustment circuit, etc. (EN) A brushless synchronous generator that can compensate for a large voltage drop that occurs and can always supply a stable voltage. [Structure] A prime mover 13, a generator 1 and an exciter 8 are directly connected by a rotary shaft, and a stator winding 2 of the generator 1 is connected to a transformer 1 of a transformer 3.
The secondary winding 4 is connected in series to the output terminal, and the load is connected to R, S and T. A reactor 7 is connected in parallel to the primary winding 4 of the transformer 3. An intermediate tap is provided on the stator winding 2 of the generator 1, the terminal of which is 2 of the transformer 3.
The secondary winding 5 is connected in series to the primary winding 4 in the opposite polarity to the rectifier circuit 6, and the DC side output terminal of the rectifier circuit 6 is connected to the stator winding 9 of the exciter 8. The rotor winding 10 of the exciter 8 is connected to the rotor rectifier circuit 11, and the rotor rectifier circuit 11 is connected to the rotor winding 12 of the generator 1.

Description

Detailed Description of the Invention

[0001]

More particularly, the present invention relates to a brushless synchronous generator that automatically compensates for large voltage fluctuations (drops) in the generator due to load fluctuations such as when starting the electric motor.

[0002]

2. Description of the Related Art Conventionally, a voltage regulator, especially a constant voltage device called AVR (automatic voltage re-gurater) has been widely used. The generator needs to control the output voltage so that the voltage fluctuation is eliminated by the load fluctuation of the connected load, and the AVR is also used here.

In the brushless self-excited synchronous generator described in Japanese Patent Laid-Open No. 61-128753, a main generator coil, a main excitation generator coil, and an exciter field coil are wound around a stator. The electromotive force of the coil is supplied to the exciter field coil through the rectifier and the voltage adjusting circuit, whereby the electromotive force is generated in the exciter generator coil in response to the magnetic pole generated in the exciter field coil, and the exciter generator coil The electromotive force is used as an exciting power source for the main field coil.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
R has the following problems. In other words, this AVR that uses electronics is a feedback control system, and there is a time delay, so it is almost useless for dealing with transient phenomena such as when starting an electric motor or when switching phases.

The device disclosed in Japanese Patent Laid-Open No. 61-128753 has a large load at the time of starting when driving a device such as an induction motor in which the load current at the time of starting changes extremely greatly. The current flows into the load and causes a large voltage drop in the main generator coil.In order to compensate for this large voltage drop, a large-scale voltage adjustment circuit or other external device must be installed, or even if it is not It is necessary to employ a generator having an output capable of covering fluctuations, which causes an increase in cost.

[0006]

In order to solve the above-mentioned problems, the present invention provides a rotor of a generator and a rotor of an exciter on the same rotary shaft, and A brushless system in which part of the output is supplied to the stator winding of the exciter via the rectifier circuit, and the output of the rotor winding of the exciter is supplied to the rotor winding of the generator via the rotary rectifier circuit. In the synchronous generator, the stator winding of the generator is connected in series to the primary winding of the transformer to serve as an output terminal and the reactor is connected in parallel to the primary winding of the transformer, and the stator of the generator is connected. An intermediate tap is provided on the winding and a part of the output of the stator winding of the generator by the intermediate tap is connected in series to the secondary winding of the transformer so that the polarity is opposite to that of the primary winding of the transformer. Then, it is configured to be supplied to the stator winding of the exciter through the rectifier circuit.

Further, a DC power source is connected in parallel with the stator winding of the exciter machine via a switch, a diode and a resistor, so that the operation is performed more reliably. Alternatively, a simple structure can be obtained by providing a transformer-combined transformer by providing a gap in the iron core magnetic path of the transformer.

[0008]

Operation: The method described below divides the distribution line into a turbulent load and a general load so that the general load is not affected by voltage fluctuations due to the turbulent load. Technology, P.225 (Showa 47-10))
Is applied to the excitation circuit of the generator.

However, the flicker booster is intended to keep the voltage of a general load connected to the flicker booster constant, but in the present invention, the magnitude of the load current is set. And the power factor, the exciting voltage of the exciter connected to the flicker booster is changed, and thus the induced voltage of the generator is changed to compensate for the voltage drop of the generator due to the change of the load current to generate power. It is designed to keep the output voltage of the machine constant.
The action is different from that of the star.

The stator winding of the generator is connected to the generator output terminal via the primary winding of the transformer, and the partial output of the generator from the intermediate tap of the stator winding is transferred to the primary winding of the transformer. Since it is connected in series to the secondary winding of the transformer so that the polarity is opposite to that of the above, and is supplied to the stator winding of the exciter through the rectifier circuit, when the load current increases and the voltage drops, , A voltage proportional to the voltage drop of the reactor in parallel with the transformer is applied to the rectifier circuit by the secondary winding of the transformer, and consequently acts to strengthen the static magnetic field of the exciter machine. In other words, the voltage drop due to the load fluctuation is eliminated by the flicker booster.
The voltage applied to the rectifier circuit increases as the voltage drop increases.
Therefore, the static magnetic field by the stator of the exciter is strengthened, the action of the exciter is also strengthened, and the generator output voltage is also increased.

By the way, the turns ratio of the primary and secondary windings of the transformer and the reactor are designed so as to increase the exciting current when the load current increases. Further, the intermediate tap position of the stator winding of the generator is designed similarly. For example, the terminal voltage of the primary and secondary windings of the transformer should be designed so that the terminal voltage of the secondary winding is large so that the static magnetic field of the exciter machine can be easily strengthened. You can

In the present invention, the reactor can be replaced by the excitation impedance of the transformer. In other words, by providing an air gap in the iron core of the transformer, a separate reactor becomes unnecessary. In this case, the reactor can be adjusted by adjusting the gap of the transformer core and adjusting the magnitude of the excitation impedance.

According to the present invention, the generator and the exciter have the same core.
It can also be applied to a generator configured with.

Further, the transformer of the present invention has an advantage that it can be used together as an ammeter for indicating a load current.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described with reference to FIG. The terminals A, B, C of the stator winding 2 of the generator 1 are connected to the output terminals R, S, T through the primary winding 4 of the transformer 3 in series, and the load is R, S, T. Connected to. A reactor 7 is connected in parallel to the primary winding 4 of the transformer 3. The stator winding 2 of the generator 1 has intermediate taps a, b, c
Is provided, and its terminal is connected to the input terminals r, s, t of the rectifier circuit 6 by connecting the secondary winding 5 of the transformer 3 in series with the polarity opposite to that of the primary winding 4 in series. Further, the DC side output terminal of the rectifier circuit 6 is connected to the stator winding 9 of the exciter machine 8.

A DC power source (battery) E is connected in parallel to the stator winding 9 of the exciter 8 via a switch S, a diode D and a resistor R.

The rotor winding 10 of the exciter 8 is connected to the input terminals m and n of the rotary rectifying circuit 11, and the DC side terminal of the rotary rectifying circuit 11 is connected to the rotor winding 12 of the generator 1. .
Further, the rotor shaft of the prime mover 13 and the generator 1 and the rotor shaft of the exciter 8 are directly connected.

The power generation operation in the above configuration will be described. First, the rotor (winding 12) of the generator 1 and the rotor (winding 10) of the exciter 8 are driven to rotate by the prime mover 13. If there is residual magnetism in the rotor of the generator 1, the rotation drive starts power generation, but here, the switch S provided in parallel with the rectifier circuit 6 is closed and the DC power source E
A direct current is applied to the stator winding 9 of the exciter 8 to create a static magnetic field. With this static magnetic field, the rotor winding 1 of the exciter machine 1
A voltage is induced at 0. This voltage is rectified by the rotary rectifier circuit 11 and supplied to the rotor winding 12 of the generator 1. By this supply, the rotor of the generator 1 becomes a rotating field, and a voltage is induced in the stator winding 2 of the generator 1. The induced voltage is output to the output terminals R, S and T. Outputs from the intermediate taps a, b, c provided on the stator winding 2 of the generator 1 are rectified by the rectifier circuit 6 through the secondary winding 5 of the transformer 3.
DC is applied to the stator winding 9 of the exciter 8 here, and the switch S is opened from this state to continue the power generation operation without the application of the DC power supply E. Will be possible.

Next, according to the present invention, the stator winding 2 of the generator 1 is connected to the output terminals R, S, T of the generator 1 through the primary winding 4 of the transformer 3, and the generator 1 The partial output of the generator 1 from the intermediate taps a, b, c of the stator winding 2 is transferred to the transformer 3
The secondary winding 5 of the transformer 3 is connected in series so as to have a polarity opposite to that of the primary winding 4, and is supplied to the stator winding 9 of the exciter 8 through the rectifier circuit 6, The operation of the configuration in which the reactor 7 is connected in parallel with the primary winding 4 of the third winding 3 will be described with reference to FIG.

FIG. 2 shows the stator winding 2 and the transformer 3 of the generator 1.
2 illustrates one phase of the circuit. The Y voltage at the terminal A of the stator winding 2 of the generator 1 is E _A, and the load current flowing out from the terminal A is I _A. The Y voltage of the intermediate tap a of the stator winding 2 of the generator 1 is E _a, and the current flowing out from the intermediate tap a is I _a . The load current I _A flows through the reactor 7. The compensation current of the current I _a flowing through the secondary winding 5 side of the transformer 3 circulates to the primary winding 4 and the reactor 7 of the transformer 3. Therefore the reactor 7 flows current _{(I A} -I _a), Inpi of the reactor 7 - When the dance and jx, j
_A voltage drop of x (IA- _Ia ) occurs. Generator Y voltage _{V R} of the output terminal R is V _R = _E A _-jX of this time (I A _-I a), and the addition Y voltage _{V r} of the input terminal r of the stator rectifier circuit 11 transformer 3 V _r = E _a + jx (I _A −I _a ), since the secondary winding 5 of V is connected in series with the opposite polarity. However, for simplicity, the turns ratio of the transformer 3 is set to 1 and the transformer 3 is described as depolarized.

Next, the voltage adjusting action of the present apparatus with respect to changes in load magnitude and load power factor will be described. First, consider when there is no load. At no load, I _A = 0. Also I _a
Is the basis of the current that creates the static magnetic field and is generally a delayed current. Therefore, I _a = −jI _a . In this case, V _R and V _r are given by the following equations.

[0022] _{V R = E A -jx (jI} a) = a voltage from _{E A + xI a V r =} E a + jx (jI a) = E a -xI a i.e. _{V R} is xI _a only _{E A} rises, V _r
Has _a voltage lower than E _a by xI _a . The design at this time is designed so that V _R = E _A + xI _a becomes the rated voltage.

Next, consider the case where a load is connected and the load current I _A is a delayed current. That is, consider the case of I _A = −jI _A. In this case _{V R = E A -jx (-jI} A + jI a) = E A -x (I A -I a) V r = E a + jx (-jIA + jI a) = E a + x (I A -I a That is, the voltage of V _r becomes higher by (xI _A ) than when there is no load. When V _r becomes large, I _a becomes large, the static magnetic field becomes strong, and E _a and E _A increase. And the load current I
Compensate for the voltage drop due to the internal impedance of the generator by _{A. V R} by the connection of the load from no load (xI
_A ) Because the voltage drops only. To obtain a constant voltage, I _a
The voltage drop of (xI _A ) must be compensated by increasing That is, E _A must be increased by (xI _A ). The action is performed by the increase of I _a described above.

Next, consider a case where a load is connected and the load current I _A is a leading current. That is, consider the case where I _A = jI _A. In this case _{V R = E A -jx (-jI} A + jI a) = E A + x (I A + I a) V r = E a + jx (-jI A + jI a) = E A -x (I A + I a ) i.e. _{V r} is a voltage only xI _a than when no load becomes lower. When V _r becomes small, I _a becomes small, the static magnetic field becomes weak, and E _a and E _A become small. And the load current I _A
To compensate the voltage rise due to the internal impedance of the generator. The connection of the load is V _R from the time of no load (x
Since the voltage increases by I _A ), in order to obtain a constant voltage, the voltage increase of (xI _A ) must be compensated by decreasing I _a . That is, E _A must be reduced by (xI _A ). The action is performed by the above-mentioned decrease of I _a .

By the way, as shown in FIG. 3, the reactor 7 according to the present invention can be replaced by the excitation impedance of the transformer 3. That is, by providing the void 15 in the iron core 14 of the transformer 3, a separate reactor becomes unnecessary. in this case,
The reactor can be adjusted by adjusting the gap 15 of the transformer core 14, and the magnitude of the excitation impedance of the transformer 3 can be adjusted. The figure shows a single phase, but naturally three phases are also possible.

The present invention is also applicable to a generator having a structure in which a generator and an exciter are combined.

Further, the transformer of the present invention has an advantage that it can be used together as an ammeter for indicating a load current.

[0028]

As described above, a large load fluctuation, which is generally seen at the time of starting the induction motor, causes a voltage drop of the output voltage of the generator. Therefore, power generation of a capacity in consideration of the voltage drop of the generator is performed. Machine, or large-scale AVR
Although the cost was increased by adding a device, the present invention makes it possible to increase the load current by simply adding a simple device such as a transformer and a reactor to the brushless synchronous generator having the configuration of the generator and the exciter. Since the exciting voltage is changed according to the power factor and the power factor to change the induced voltage of the generator to compensate the voltage drop of the generator due to the load current, even if there is a large load change due to a transient phenomenon, It is possible to provide a generator that can supply a stable voltage with little fluctuation. This also eliminates the need to install a large-capacity generator in anticipation of voltage drop due to load fluctuations, and makes it possible to select an appropriate generator that matches the size of the load.
It can greatly contribute to the cost reduction of these facilities.

[Brief description of drawings]

FIG. 1 is a diagram showing connection of a brushless synchronous generator of the present invention.

FIG. 2 is a diagram showing an operation of an output voltage from a stator winding of a generator, an output voltage from an intermediate tap, and a connection between a transformer and a reactor of the present invention.

FIG. 3 is a diagram showing an example in which a reactor is replaced by an excitation impedance of a transformer.

[Explanation of symbols]

 1 Generator 2 Stator winding of generator 3 Transformer 4 Primary winding of transformer 5 Secondary winding of transformer 6 Rectifier circuit 7 Reactor 8 Exciter 9 Stator winding of exciter 10 Rotation of exciter Child winding 11 Rotor rectifier circuit 12 Generator rotor winding 13 Motor 14 Iron core 15 Void

Claims (3)

[Claims] 1. A rotor of a generator and a rotor of an exciter are arranged on the same rotary shaft, and a part of output of a stator winding of the generator is wound on a stator winding of the exciter through a rectifier circuit. In a brushless synchronous generator in which the output of the rotor winding of the exciter is supplied to the rotor winding of the generator via a rotary rectifier circuit, the stator winding of the generator is modified. Connected to the primary winding of the transformer in series as an output terminal, and connecting the reactor in parallel to the primary winding of the transformer, and providing an intermediate tap on the stator winding of the generator to A partial output of the stator winding is connected in series to the secondary winding of the transformer so as to have a polarity opposite to that of the primary winding of the transformer, and the stator winding of the exciter is connected through the rectifier circuit. A brushless synchronous generator characterized by being supplied to. 2. The brushless synchronous generator according to claim 1, wherein a DC power source is connected in parallel with the stator winding of the exciter through a switch, a diode and a resistor. Brushless synchronous generator. 3. The brushless synchronous generator according to claim 1, wherein an air gap is provided in the iron core magnetic path of the transformer to form a transformer that also serves as a reactor.