JPH0546200B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an excitation device for a generator,
This is to prevent fluctuations in the generator output due to rotational fluctuations during light loads, etc., and to obtain stability.

(Prior Art) In general, self-excited generators require a large exciter voltage in order to establish voltage during load. However, since the voltage generated by the exciter coil changes in proportion to the rotational speed of the rotor, the generated voltage becomes excessively high when the rotor is rotating at high speed and the load is light. Therefore, when the automatic voltage regulator is on, high voltage is supplied to the excitation coil, and when the automatic voltage regulator is switched on and off, the magnetic flux generated by the excitation coil changes greatly, and this change in magnetic flux causes the rotor to Rotational fluctuations and fluctuations in the main coil's generated voltage become large. If the fluctuation in the voltage generated by the main coil increases, the automatic voltage regulator will be turned on and off frequently, resulting in further fluctuation in the output voltage. For this reason, when the load is a light bulb, so-called flickering occurs.

(Objective of the Invention) The present invention has been made in view of this point, and its purpose is to prevent fluctuations in the generator output due to rotational fluctuations during light loads, etc., without interfering with voltage establishment. An object of the present invention is to provide an excitation device for a generator that enables the excitation of a generator.

(Structure of the Invention) To achieve this object, the present invention provides a generator having a main coil connected to a load, an excitation coil for exciting magnetic poles, and an exciter coil for obtaining a voltage to be supplied to the excitation coil. , a rectifier is connected to the exciter coil, the excitation coil is connected to the output side of the rectifier via a transistor that controls an output voltage, and a damping coil is provided in the same magnetic path as the exciter coil to generate magnetic flux, The damping coil is connected to both ends of the DC side of the rectifier connected to the exciter coil via a Zena diode in series. As a result, when the voltage obtained from the exciter coil via the rectifier reaches a level higher than the Zena voltage of the Zena diode, current flows to the damping coil, and when the voltage generated by the exciter coil at high rotation is high, the damping coil is damped. By energizing the coil and suppressing the voltage generated by the exciter coil, the magnetic flux of the exciting coil is reduced, preventing frequent on/off switching of the automatic voltage regulator, and preventing rotational fluctuations and fluctuations in the generated voltage. This is what I did.

(Example) Below, an example of the present invention will be explained with reference to the drawings. First, in Fig. 1, 1 is a self-excited generator driven by an engine, 2 is an automatic voltage regulator, and 3
is the load. The generator 1 includes a main generating coil (hereinafter referred to as the main coil) 4, an auxiliary generating coil (hereinafter referred to as the exciter coil) 5, and an excitation coil 6.
The main coil 4 and the exciter coil 5 are wound around the stator shown by reference numeral 7 in FIG. 2, and the exciting coil 6 is wound around the rotor 8. It is of a type that supplies the obtained voltage to the excitation coil 6. This generator 1 is further provided with a damping coil 9, which is wound around the stator 7 as shown in FIG. 2, and is in the same magnetic path as the exciter coil 5.
A DC magnetic path is generated by a voltage obtained from a first rectifier circuit, which will be described later. In addition, load 3
is connected to both ends of the main coil 4 with a no-use breaker 10 interposed at one end thereof.

The automatic voltage regulator 2 is interposed between the exciter coil 5 and the excitation coil 6 of the generator 1, and controls the excitation operation of the excitation coil 6 using the voltage from the exciter coil 5.The circuit configuration thereof will be explained below. Then, 11 is the first rectifier circuit.

The first rectifier circuit 11 has its input side connected to both ends of the exciter coil 5, and performs full-wave rectification of the output voltage from the exciter coil 5. A capacitor 12 is connected to both ends of the DC side, which is the output side, of the first rectifier circuit 11.
These common connection points are connected to the negative side of the excitation coil 6. The damping coil 9 is connected in parallel with the capacitor 12 to both ends of the first rectifier circuit 11 on the DC side via Zena diodes 13 in series.

Reference numeral 14 denotes a flywheel diode, which is connected in antiparallel to the excitation coil 6 and is designed to provide a flywheel effect to the excitation coil 6.

In addition to the above configuration, the automatic voltage regulator 2 includes a second rectifier circuit 15, a voltage detection transistor 16, and a control transistor 17 forming a Darlington circuit.
and a power transistor 18 and a zener diode 1
9, capacitors 20, 21, 22, and resistor 2
3, 24, 25, 26, 27, 28, and 29, but since these circuit configurations are the same as those of the conventional one, detailed explanations thereof will be omitted here by showing them in the drawings.

Next, the operation of this embodiment configured as described above will be explained.

Now, when the rotor 8 rotates, a voltage is generated in the exciter coil 5 due to the residual magnetic flux, and this voltage turns on the control transistor 17, which also turns on the power transistor 18, and the excitation power of the excitation coil 6 increases. Granted. Then, due to the excitation of the excitation coil 6 and the increase in the rotational speed of the rotor 9, the voltage generated in the main coil 4 rapidly increases and becomes established. After this voltage is established, if the voltage generated by the main coil 4 exceeds the set voltage,
Zena diode 19 becomes conductive and voltage detection transistor 16 is turned on. As a result, the control transistor 17 is turned off, the power transistor 18 is also turned off, and no power is supplied to the excitation coil 6, so that the voltage generated by the main coil 4 decreases. Due to this drop, the Zener diode 19 becomes non-conductive again, so the voltage detection transistor 16 is turned off, and the control transistor 17 is turned on, so the power transistor 18 is also turned on, and the exciting power is applied to the exciting coil 6. will be granted. By repeating this operation, the voltage generated by the main coil 4 is kept constant.

By the way, after the voltage is established, capacitor 1
As long as the voltage Ec (exciter voltage) across the terminal 2 reaches and exceeds the voltage Ecz of the zener diode 13, the zener diode 13 becomes conductive, and as a result, the voltage Ec-Ecz and the resistance of the damping coil 9 decrease. A current determined by R flows through the damping coil 9, and a DC magnetic flux in the direction of arrow X is generated as shown in FIG.
As a result, the saturation of the magnetic path of the stator core is accelerated, and the voltage generated in the main coil 4 and exciter coil 5 is suppressed and tends to decrease. The generated voltage is suppressed, and as a result, the conduction angle of the power transistor 18 is widened. This eliminates the sensitive on/off switching of the control transistor 17 and stabilizes the rotation of the rotor 8. Therefore, the stability of the voltage generated by the main coil 4 of the generator 1 is improved, and flickering caused by rotational fluctuations during light loads is suppressed when the load is an electric light or the like. On the other hand, when the load increases, the exciter voltage Ec
As a result, the current flowing through the damping coil 9 is reduced accordingly, and the output of the generator 1 is maintained.

In addition, the zener voltage Ecz and the resistance R of the damping coil 9 were determined by tests when the power transistor 18 of the automatic voltage regulator 2 was switched on and off, etc.
The most preferable value is selected by looking at the flicker when the light is actually turned on.

(Effects of the Invention) Since the present invention is constructed as described above, when the voltage generated by the exciter coil is large as in the conventional case, the voltage supplied to the excitation coil becomes high and the excitation is performed. It is possible to stabilize the changes in the magnetic flux generated by the coil, which causes fluctuations in the rotation of the rotor and fluctuations in the voltage generated by the main coil when the engine speed is high under light load conditions. Therefore, it is possible to prevent output overshoot and the like with a relatively simple configuration even at light load without impeding voltage establishment, resulting in improved stability. This makes it possible to prevent flickering when the load is a light, etc., and to realize comfortable use of the generator.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing the configuration of the device of the present invention;
FIG. 2 is a diagram showing a schematic configuration of a generator equipped with a damping coil according to the present invention. 1... Generator, 5... Exciter coil, 6...
...Exciting coil, 9...Damping coil, 11...
... Rectifier, 13 ... Zena diode, 17 ... Control transistor, 18 ... Power transistor, 1
9...Zena diode.

Claims (1)

[Claims] 1. In a generator that has a main coil connected to a load, an excitation coil that excites magnetic poles, and an exciter coil that obtains a voltage to be supplied to the excitation coil, a rectifier is connected to the exciter coil, and the rectifier is connected to the exciter coil. The excitation coil is connected to the output side via a transistor that controls the output voltage, and a damping coil that generates magnetic flux is provided in the same magnetic path as the exciter coil, and the damping coil is connected via a Zena diode in series. An excitation device for a generator, characterized in that it is connected to both ends of a DC side of a rectifier connected to the exciter coil.