JPH0461600B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a voltage regulator applicable to a self-excited alternating current generator.

(Prior art) In a self-excited alternating current generator, an auxiliary coil separate from the output coil is provided on the stator side where the output coil for extracting electric power is installed, and the voltage induced in this auxiliary coil is adjusted through a voltage adjustment circuit. It is designed to be supplied to the field coil. The voltage adjustment circuit is equipped with a transistor (main transistor, which will be described later) that is cut off when the voltage induced in the auxiliary coil exceeds a certain value, and becomes conductive when the voltage is below a certain value, to keep the output voltage constant. It's summery.

Conventional voltage regulating circuits that operate in this manner have no problems with ordinary light bulb loads, but if the load is capacitive or has a phase advance characteristic, There is a problem that the output voltage may rise abnormally. In other words, if the load is capacitive or has a phase advance characteristic, and a back electromotive force is generated in the field coil and a reverse current flows, this is short-circuited to reduce the output voltage. However, in this case, there is a problem in that it is necessary to prevent the transistor from burning out due to this short-circuit current.

(Object of the Invention) The present invention has been made in view of this point, and is intended to prevent the output voltage from rising abnormally even if the load is capacitive. In addition, the capacitance of the transistors that make up the circuit is made as small as possible,
Furthermore, reliability has been improved.

(Structure of the Invention) In order to achieve the above object, the present invention provides a self-excited AC electric machine in which the voltage generated in the auxiliary coil of a generator is controlled by a main transistor and is supplied to a field coil to generate electricity. A flywheel diode and an auxiliary transistor connected in parallel to the field coil are provided in a voltage regulator circuit that connects the auxiliary coil and the field coil, and a second voltage regulator higher than the reference voltage at which the voltage regulator operates is provided. A setting circuit is provided to set the reference voltage of
The auxiliary transistor is made conductive during a period when the reference voltage is higher than the reference voltage, and is cut off during a period when the reference voltage is lower than the reference voltage.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1. 1 is an output coil of an alternating current generator (hereinafter referred to as a generator) (not shown), 2 is an auxiliary coil, and 3 is a field coil. It is a coil. The output coil 2 is connected not only to a load (not shown) but also to the input side of a rectifier circuit 4. The input side of the rectifier circuit 5 is connected to the auxiliary coil 2 . A capacitor 6 is connected to the output side of the rectifier circuit 5, and
A series circuit of field coil 3 and transistor 7 is connected. A diode 8 is connected in parallel to the transistor 7, and a transistor 9 and a flywheel diode 10 are connected in parallel to the field coil 3.

Transistor 7 acts as a main transistor and transistor 9 acts as an auxiliary transistor. These transistors 7 and 9 perform a specific function, which will be described later, to keep the output voltage constant. On the output side of the rectifier circuit 4, a capacitor 12 and two
series resistors 13, 14 and parallel circuits 15, 16 are connected. The resistance values of the circuits of resistors 13 and 14 and the circuits of resistors 15 and 16 are appropriately selected, and the divided voltage of resistors 15 and 16 is determined from the divided voltage of resistors 13 and 14 (reference voltage). is set so that it has a slightly higher value (second reference voltage).

The connection point between the resistors 13 and 14 is connected to one end of each of the resistors 18 and 19 via a Zener diode 17.
One pole of the capacitor 20 is connected. The other end of the resistor 19 is connected to the rectifier circuits 4 and 5 which are connected in common.
is connected to the negative pole side (hereinafter referred to as the ground line) of the A diode 21 is connected in parallel to the resistor 19, and the base of a transistor 22 is connected to the side connected to the Zener diode 17.
The emitter of the transistor 22 is connected to the ground line, and the collector is connected to the other terminal of the capacitor 20, one end of the resistor 23, and the base of the transistor 7. The other end of the resistor 23 is the field coil 3
The positive electrode side of the rectifier circuit 5 (hereinafter referred to as
(referred to as the positive line). Resistor 18
A capacitor 24 is connected in series to the connection point of the transistors 9 and 7.

One end of a resistor 26, the cathode of a diode 27, and the base of a transistor 28 are connected to a connection point between the resistors 15 and 16 via a Zener diode 25. The other end of the resistor 26, the anode of the diode 27, and the emitter of the transistor 28 are connected to the ground line, and the collector of the transistor 28 is connected to the positive line through a series circuit of resistors 29 and 30. Resistance 29,3
The connection point 0 is connected to the base of a transistor 32 via a resistor 31. transistor 3
The emitter of transistor 2 is connected to the positive line, and the collector is connected to the pace of transistor 9.

This device configured in this way operates as follows. First, a case where the load is a light bulb or the like and does not have a phase advance characteristic will be explained. When the rotor of the generator is driven to rotate and an output voltage is generated in the output coil 1, this voltage is supplied to a light bulb or the like (not shown). At the same time, this voltage is applied to the rectifier circuit 4, the resistor 11, and the capacitor 12.
The signal is rectified and smoothed at , and then supplied to resistors 13 and 14 . The connection point between the resistors 13 and 14 is connected to the transistor 22 via the Zener diode 17.
Since it is connected to the base of the transistor 22, when the divided voltage exceeds a certain value (Zena voltage), the transistor 22
becomes conductive.

When the output voltage generated in the output coil 1 is less than a preset reference voltage, that is, the operating voltage of the Zener diode 17 in the circuit shown in the figure (see FIG. 2), no voltage adjustment is performed;
The voltage generated in the auxiliary coil 2 is applied to the field coil 3 via the transistor 7 which is conducting in that state.
will be supplied to the system to generate electricity. When the output voltage increases and the Zener diode 17 becomes conductive, the transistor 22 becomes conductive, so the transistor 7 is cut off and the current to the field coil 3 is limited.
Reduce generator output. This process is repeated as appropriate to adjust the voltage.

The output voltage Vc of the rectifier circuit 4 is a pulsating DC voltage as shown in FIG. This is adjusted to a constant voltage (reference voltage) by the above-mentioned action. In the present invention, a second reference voltage slightly higher than the reference voltage is set by the resistors 15 and 16, and the Zener diode 25 and the transistor 28
When the output voltage Vc reaches this voltage, the transistor 28 is made conductive, so the transistor 9 is also made conductive, and the field coil 3 is short-circuited. When transistor 28 is cut off, transistor 9 is also cut off. Note that since the two reference voltages are different, the transistors 7 and 9 will not be conductive at the same time.

Next, let us consider the case where the load is short-lived or has a phase advance characteristic. In this case, a back electromotive force may be generated in the field coil 3, and a reverse current may flow. When a reverse current flows, the current is bypassed through the transistor 9, and the alternating current is short-circuited by the flywheel diode 10 and the transistor 9, thereby preventing an increase in the output voltage. If the transistors 7 and 9 are turned on at the same time, the short-circuit current of the capacitor 6 will flow through these transistors 7 and 9, causing them to burn out. However, in the present invention, since the two reference voltages are different from each other as described above, the transistors 7 and 9 do not become conductive at the same time, so this does not occur.

(Effects of the Invention) Since the present invention is constructed as described above, it does not require a transistor with a large capacity that can tolerate an instantaneous short circuit of the power supply when the transistor is turned on or off, so that the overall size can be reduced. It can also be made cheaper. Furthermore, since there is no power supply short circuit between the main transistor and the auxiliary transistor, there is no failure and reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, and FIG. 2 is a graph explaining the operation of the circuit shown in FIG. 1... Output coil, 2... Auxiliary coil, 3...
Field coil, 7, 9...transistor, 10...
flywheel diode.

Claims (1)

[Claims] 1. In a self-excited alternating current generator in which the voltage generated in the auxiliary coil of the generator is controlled by a main transistor and supplied to the field coil to generate electricity, a voltage regulator that connects the auxiliary coil and the field coil. A flywheel diode and an auxiliary transistor connected in parallel to the field coil are provided in the circuit, and a setting circuit is provided for setting a second reference voltage slightly higher than the reference voltage at which the voltage regulator operates;
A voltage regulating device for an alternator, characterized in that the auxiliary transistor is made conductive during a period when the output voltage is higher than the second reference voltage, and is cut off during a period when the output voltage is lower than the second reference voltage.