JPH0348759B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a voltage regulator that can be used in 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 supply the field coil. The voltage adjustment circuit is provided 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.
The output voltage is kept constant.

Conventional voltage regulator 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. That is, if the load is capacitive or has a phase advance characteristic, a back electromotive force may be generated in the field coil and a reverse current may flow, so it is necessary to prevent this.

Therefore, if such a reverse current flows, it may be possible to short-circuit it to prevent the output voltage from increasing.For this purpose, an auxiliary transistor is provided separately from the main transistor to prevent the reverse current caused by the reverse power. It is conceivable to short-circuit the transistor, but in this case, there is a problem in that the transistor must be prevented from burning out due to this short-circuit current.

(Problem to be solved by the invention) The present invention has been made in view of this point,
Even if the load is capacitive or has a phase advance characteristic, it is possible to prevent the output voltage from rising abnormally, and to minimize the capacitance of the transistors that make up the circuit. The present invention aims to provide a voltage regulator for an alternating current generator.

(Means for Solving the Problems) As a means for solving the above problems, the present invention rectifies the AC output voltage generated in the output coil 1 of the generator by a rectifier circuit 4, and adjusts the voltage according to the rectified voltage. By making the main transistor 7 conductive and cut-off, a voltage is generated in the auxiliary coil 2 and the rectifier circuit 5
In a self-excited alternator that controls the supply of power rectified by a field coil 3 to adjust the output voltage of the generator, a flywheel diode 10 and an auxiliary transistor 9 are connected in parallel to the field coil 3. A capacitor 30 is provided which is connected to the main transistor 7 and charged by the field current of the field coil 3 flowing through the flywheel diode 10 when the main transistor 7 changes from conduction to cutoff. A parallel circuit of a resistor 33 and a diode 34 is connected in series, and a resistor 31 is connected in parallel to one end of the field coil 3.
The transistor 26 becomes conductive as charging progresses to 0.
A transistor 27 is provided which becomes conductive when the transistor 26 conducts, and the collector of the transistor 27 is connected to the base of the auxiliary transistor 9, and the emitter of the auxiliary transistor 9 is connected to the other end of the field coil 3. In addition, it is connected to the positive output terminal of the rectifier circuit 5.

(Function) With this configuration, the auxiliary transistor 9, which bypasses the reverse current when the load is capacitive or has a phase advance characteristic, can prevent the main transistor 7 from conducting. When it changes, it will be completely cut off and then conductive. On the other hand, when the main transistor 7 changes from cutoff to conduction, the auxiliary transistor 9 turns off at an early stage. Therefore, short-circuiting of the charges in the capacitor 6 due to the series circuit of the main transistor 7 and the auxiliary transistor 9 will not occur.

(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, and the other part is a voltage control circuit 35. Each of the above-mentioned coils is connected to each part of this voltage control circuit 35 as follows. 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 the field coil 3 and the main transistor 7 is also connected. A diode 8 is connected in parallel to the main transistor 7, and an auxiliary transistor 9 and a flywheel diode 10 are connected in parallel to the field coil 3.

The main transistor 7 and the auxiliary transistor 9 perform a predetermined function, which will be described later, to maintain the output voltage at a constant value. A resistor 1 is installed on the output side of the rectifier circuit 4.
1, a capacitor 12 and a parallel circuit of two series resistors 13 and 14 are connected. A Zener diode 15 is connected to the connection point between the resistors 13 and 14.
One end of each of resistors 16 and 17 and one end of capacitor 18 are connected via. The other end of the resistor 17 is connected to the negative electrode side (hereinafter referred to as a ground line) of the rectifier circuits 4 and 5 that are connected in common.

A diode 19 is connected in parallel to the resistor 17, and the base of a transistor 20 is connected to the side connected to the Zener diode 15. The emitter of transistor 20 is connected to the ground line,
The collector is connected to one end of the resistor 21 and the base of the transistor 22 along with the other pole of the capacitor 18 . The other end of the resistor 21 is connected to the positive pole side (hereinafter referred to as a positive line) of a rectifier circuit 5 connected to one end of the field coil 3. A capacitor 23 is connected in series to the resistor 16, and a transistor 2
2 and the collector of the main transistor 7. The emitter of transistor 22 is connected to the base of main transistor 7.

There is a resistor 2 between the positive line and the ground line.
4 and 15 and a transistor 26 are connected in series. The base of a transistor 27 whose emitter is connected to the positive line and whose collector is connected to the base of the auxiliary transistor 9 is connected to the connection point between the resistors 24 and 25. A resistor 28, a diode 29, and a capacitor 30 are connected in parallel between the base of the transistor 26 and the ground line. The base of the transistor 26 is connected to the resistor 31.
The main transistor 7 and the auxiliary transistor 9 are
connected to the connection point.

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 rectified and smoothed by the rectifier circuit 4, resistor 11, and capacitor 12, and then supplied to resistors 13 and 14. Since the connection point between the resistors 13 and 14 is connected to the base of the transistor 20 via the Zener diode 15, when the divided voltage exceeds a certain value (Zena voltage), the transistor 20 becomes conductive.

When the output voltage generated in the output coil 1 is lower than the preset voltage, that is, the operating voltage of the Zener diode 15 in the circuit shown in the figure, no voltage adjustment is performed, and the voltage generated in the auxiliary coil 2 is The power is supplied to the field coil 3 via the main transistor 7 which is conducting, and generates electricity. When the output voltage increases and the Zener diode 15 becomes conductive, the transistor 20
conducts, transistor 22 is cut off, and thus main transistor 7 is also cut off, limiting the current to field coil 3 and reducing the output voltage of the generator. This process is repeated as appropriate to adjust the voltage.

In this case, when the main transistor 7 changes from conduction to cutoff, the field current if
flows continuously through the flywheel diode 10, and its collector voltage rises rapidly to become close to the potential of the capacitor 6. As a result, the capacitor 30 is charged with a current flowing through the resistor 31 and the circuit of the capacitor 32 and the resistor 33, and when the potential of the capacitor 30 exceeds the voltage between the base and emitter of the transistor 26, the transistor 26 becomes conductive. 27 also becomes conductive, and the auxiliary transistor 9 becomes conductive. Due to this time delay, the auxiliary transistor 9 is turned on after the main transistor 7 has completely shut off (see FIG. 2).

Next, when the main transistor 7 changes from cutoff to conduction, the collector voltage of the main transistor 7 will rapidly drop from a value close to the potential of the capacitor 6 to a value close to zero volts. When this voltage begins to drop, capacitor 32 and diode 34
Since the base potential of the transistor 26 is lowered through the transistor 26, the transistor 26 is cut off, and the transistor 27 is also cut off, so that the auxiliary transistor 9 is cut off. That is, the auxiliary transistor 9 is cut off at an early stage when the main transistor 7 starts to change from cutoff to conduction (see FIG. 2). Main transistor 7 and auxiliary transistor 9
This action prevents the charges in the capacitor 6 from being short-circuited.

Next, consider the case where the load is capacitive 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 auxiliary transistor 9, thereby preventing an increase in the output voltage. At this time, the main transistor 7
When auxiliary transistor 9 and auxiliary transistor 9 conduct at the same time, the short circuit current of capacitor 6 flows to
This causes the main transistor 7 and the auxiliary transistor 9 to burn out. However, in the present invention, as described above, the main transistor 7 and the auxiliary transistor 9 are not rendered conductive at the same time, so this does not occur.

(Effects of the Invention) Since the present invention is a voltage regulator for an alternator configured as described above, when the load is capacitive or has a phase advance characteristic, the output voltage is Even if a flywheel diode and an auxiliary transistor are connected in parallel with the field coil to prevent the voltage from rising abnormally, the auxiliary transistor will not conduct at the same time as the main transistor, so the timing shown in Figure 3 will occur. Unlike conventional transistors, which operate normally, there is no need to use transistors, which conventionally had a large capacity to withstand short circuits in the power supply circuit. This allows the device to be made smaller and cheaper. Furthermore, destruction of the transistor due to instantaneous transient current can be prevented, and reliability can be improved.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a graph explaining the operation of the device shown in FIG. 1, and FIG. 3 is a graph explaining the operation of the conventional device. 1... Output coil, 2... Auxiliary coil, 3...
Field coil, 4... Rectifier circuit, 7... Main transistor, 9... Auxiliary transistor, 10... Flywheel diode, 35... Voltage control circuit.

Claims (1)

[Claims] 1. The AC output voltage generated in the output coil 1 of the generator is rectified by the rectifier circuit 4, and the main transistor 7 is turned on and off according to the rectified voltage, so that the AC output voltage generated in the auxiliary coil 2 is generated in the rectifier circuit 5.
In a self-excited alternator that controls the supply of power rectified by a field coil 3 to adjust the output voltage of the generator, a flywheel diode 10 and an auxiliary transistor 9 are connected in parallel to the field coil 3. A capacitor 30 is provided which is connected to the main transistor 7 and charged by the field current of the field coil 3 flowing through the flywheel diode 10 when the main transistor 7 changes from conduction to cutoff. A parallel circuit of a resistor 33 and a diode 34 is connected in series, and a resistor 31 is connected in parallel to one end of the field coil 3.
The transistor 26 becomes conductive as charging progresses to 0.
A transistor 27 is provided which becomes conductive when the transistor 26 conducts, and the collector of the transistor 27 is connected to the base of the auxiliary transistor 9, and the emitter of the auxiliary transistor 9 is connected to the other end of the field coil 3. A voltage regulator for an alternator, characterized in that the voltage regulator is connected to the positive output terminal of the rectifier circuit 5.