JP3367134B2 - Excitation current control device for self-excited AC generator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exciting current controller for a self-excited AC generator.

[0002]

2. Description of the Related Art Although a self-excited AC generator has a simple structure, it has a drawback that the exciting current flowing through the exciting coil is small at the start of power generation and the power generation capacity is low at low speed.
In order to improve this problem, Japanese Patent Laid-Open No. 55-139035 filed by the applicant of the present invention discloses a rectifier composed of one resistor 100 and two diodes 101 and 102 as shown in FIG. The generated voltage of 103 is rectified, and the rectified voltage is supplied to the base of the switching transistor 105 through the resistor 104. As a result, at the start of power generation, the power generation voltage generated by the residual magnetism is transmitted through the resistors 100 and 104 to the switching transistor 1
05 is applied to the base of the switching transistor 1
When 05 is activated, the exciting current is passed through the exciting coil 106, and the generated voltage is increased. Further, a bypass resistor 107 is connected in parallel with the switching transistor 105 in order to further increase the exciting current.

[0003]

However, in the exciting current control device of the above-mentioned publication, in order to turn on the transistor 105, the generated voltage needs to exceed the sum of the voltage drop of the resistors 100 and 104 and the Vbe of the transistor 105. However, there is a drawback in that Vbe increases at a low temperature, so that the number of revolutions during power generation rises, that is, the number of revolutions at which the transistor 105 is turned on to supply the exciting current to the exciting coil, increases.

Also, one for each phase of the armature coil 103.
It is necessary to connect one resistor 100 and two diodes 101 and 102, which has a drawback that the component configuration of the generator 1 becomes complicated. The present invention has been made in view of the above problems, and it is an object of the present invention to provide an exciting current control device capable of starting power generation from a remarkably lower rotation speed than conventional ones and simplifying the component configuration of a self-excited alternator. Has an aim.

[0005]

SUMMARY OF THE INVENTION An exciting current control device for a self-excited alternator according to the present invention is provided with an exciting coil of an alternator having a three-phase full-wave rectifier for supplying a rectified generated current to a high end of a battery in series. Connected to the battery from the high end of the
In a magnetizing current control device for a self-excited AC generator having a switching transistor for intermittently controlling energization of a magnetic coil and having no ignition switch, a one-phase generated voltage or a neutral point voltage of the generator is 0.7V or more. Set small
A power generation start discriminating means for outputting a power generation start signal when it exceeds a predetermined threshold level that is, the Sui from high end of the battery with conductive by receiving the power generation start signal
By supplying power to the control terminal of the
And a control switch for turning on the switching transistor .

[0006] In a preferred embodiment,The switching
The transistor drive circuit isAfter the operation of the control switch, before
WritingContinuing the conduction of the control switch, and
Generated voltage or neutral point voltage is above a certain level for a certain period of time or less
If it drops to beforeWritingThe switch that interrupts the continuity of the switch
Equipped with a field circuit.In a preferred embodiment, the power generation start
The starting determination means is a one-phase generated voltage or neutral point voltage of the generator.
The pressure corresponding to the base electrode and the threshold level.
Is it a pair of pnp transistors that detect the difference with a certain value voltage?
Has a differential input stage consisting of, and controls the control switch.
It consists of a comparator.

[0007]

The self-excited AC generator supplies the battery with the rectified generated current from the output terminal of the three-phase full-wave rectifier. By connecting and disconnecting the switching transistor, the exciting current supplied from the battery or the three-phase full-wave rectifier to the exciting coil is interrupted and the generated voltage is adjusted.

The power generation start judging means, which is one of the features of the present invention, judges whether the one-phase generated voltage or the neutral point voltage of the generator exceeds a predetermined level, and outputs a power generation start signal when the voltage exceeds the predetermined level. To do. According to another aspect of the present invention, there is provided a base current control switch in which an output terminal of a three-phase full-wave rectifier, that is, a high potential terminal of a battery is connected to a base of a switching transistor through a current limiting resistor. Is turned on by the input of the power generation start signal to turn on the switching transistor, and an exciting current is passed through the exciting coil to start power generation.

[0009]

As described above, the exciting current control device for the self-excited AC generator of the present invention detects the excess of the predetermined level of the one-phase generated voltage or the neutral point voltage of the generator by the power generation start judging means. , When this excess is detected, a configuration is adopted in which the base current is supplied to the switching transistor from the output end of the three-phase full-wave rectifier, that is, the high end of the battery via the current limiting resistor, so at a much lower rotational speed than before. It is possible to start the power generation by passing an exciting current through the exciting coil.

That is, in the present invention, the generated voltage of the generator only functions as a control signal indicating the start of power generation, and it is not necessary to function as a power source for supplying a base current to the base of the switching transistor as in the conventional case. Since it does not exist, the generated voltage is Vbe of the switching transistor
(Base / emitter forward bias voltage, about 0.7V) It is not necessary to exceed the voltage drop of the resistor or the resistance, and it is possible to energize the exciting current with a lower generation voltage than before, which reduces the power generation start-up speed. can do.

[0011]

(Embodiment 1) An embodiment of an exciting current controller for a self-excited AC generator according to the present invention will be described with reference to FIG.
The self-excited AC generator 1 is driven by a vehicle engine, and each phase generated voltage of a star-connected three-phase armature coil 11 is rectified by a three-phase full-wave rectifier 12 and then a power line L1. Is supplied to the battery 3 through.

The exciting current control device 2 will be described below. The one-phase power generation voltage Vac output from one of the armature coils 11 is input to the negative input terminal of the comparator (power generation start determining means in the present invention) 4 through the resistor r1 and compared with the reference voltage V1. The reference voltage V1 is 0.7 V or less, 0.4 V here, and the one-phase generated voltage Va
When c becomes 0.4 V or more, the comparator 4 applies a low level output voltage (power generation start signal in the present invention) to the base of the pnp transistor (base current control switch in the present invention) 6 through the base current limiting resistor r2, The transistor 6 is turned on. The standby current consumption of the comparator is set to be sufficiently small, and a differential input stage composed of a pair of pnp transistors is adopted so that the comparator can operate at a low voltage of 0.4V. .

The turned-on transistor 6 is connected to the power supply line L1.
From the internal power supply line L2
To a level close to the battery voltage. The internal power supply line L2 is connected to the base of the switching transistor 7 through the base current limiting resistor r3, the transistor 6 that is turned on turns on the switching transistor 7, and the switching transistor 7 that is turned on excites the excitation coil 13 from the power supply line L1. An electric current is applied, which strengthens the magnetic field and proportionally increases the generated voltage.

The internal power supply line L2 is fed back to the negative input terminal of the comparator 4 through the resistor r4 and the diode D1.
Becomes high level, the comparator 1 continuously outputs low level. However, the resistor r4 and the diode D1
The connection node A with is a grounded emitter npn transistor 8
It is connected to the collector of 0 and its potential is controlled by the transistor 80. The base of the transistor 80 is controlled by the comparator 82, and the reference voltage V2 (here, 6V) is input to the + input terminal of the comparator 82.

On the other hand, the one-phase generated voltage Vac is half-wave rectified by the diode D2 and then applied to the capacitor c and the discharge resistor r5 which are connected in parallel to each other, whereby the one-phase generated voltage Vac is rectified in the capacitor c. The voltage Vc is accumulated, and this rectified voltage c is applied to the-input terminal of the comparator 82. After all, as shown in FIG. 2, the one-phase generated voltage Va
When c inverts the comparator 4 and turns on the transistor 6, the switching transistor 7 turns on, and at the same time, the power supply voltage is applied to the comparator 82 to turn on the transistor 80. In this state, the one-phase generated voltage Vac changes. Following this, the comparator 4 is turned on and off, and the switching transistor 7 is turned on and off.

When the one-phase generated voltage Vac further increases and the rectified voltage Vc exceeds V2, the transistor 80 is turned off and the potential at the connection node A rises. From the connection node A through the diode D1, the negative input terminal of the comparator 4 is obtained. High-level potential is fed back to the one-phase generated voltage V
The conduction of the transistor 6 is maintained even in the period when ac is V1 or less.

When the rotation of the generator 1 is stopped, the capacitor c is discharged, the comparator 82 turns on the transistor 80, the connection node A becomes low level, and the comparator 4
Outputs a low level, and the transistor 6 turns off and returns to the original state. Note that if the rectified generated voltage rises too much, the resistor r6, the Zener diode D3, the resistor r6 are discharged from the power line L1.
Current flows through 7. As a result, power is supplied to the base of the transistor 5 from the connection node of the Zener diode D3 and the resistor r7, the transistor 5 is turned on, and the transistor 5 lowers the base potential of the switching transistor 7 to turn off the switching transistor 7, thereby generating voltage. Suppress control.

In the excitation current control device of this embodiment described above, the transistor 6 is turned on and the switching transistor 7 is turned on by detecting a slight increase in the one-phase generated voltage Vac, so that the excitation is performed at a low rotational speed. It becomes possible to start the energization of the electric current, and it is possible to significantly reduce the power generation start-up rotation speed as compared with the conventional case. In addition, the one-phase generated voltage Vac
With a slight increase in the voltage, a much higher battery voltage than the one-phase generated voltage Vac can be applied to the base of the switching transistor 7 through the transistor 6, so that the switching transistor 7 is sufficiently large in the low rotation speed state of the generator 1. A base current can be passed and a large exciting current can be secured.

Further, since the holding circuit 8 is provided for maintaining the low level output of the comparator 4 by the conduction of the transistor 6 and canceling this continuation when the power generation is stopped, even if the power generation is detected by the one-phase power generation voltage Vac. Nevertheless, the switching transistor 7 can be continuously turned on. The hold circuit 8 includes a resistor r4, a diode D1, and a transistor 8 as shown in the figure.
0, a comparator 82, a capacitor c, a resistor r5, and a diode D2. The comparators 4 and 82 can be replaced by functionally equivalent differential amplifiers. (Embodiment 2) Another embodiment will be described with reference to FIG. However, components having similar functions to those of the first embodiment are designated by the same reference numerals.

The exciting current control device 2 differs from the exciting current control device 2 of the first embodiment in that a resistor r8 is provided instead of the resistors r4 and r1 and the diode D1 and the input polarity of the comparator 82 is different. ing. That is, the collector of the transistor 80 is connected to the base of the transistor 6 through the resistor r8.

Explaining the operation of this device, when the one-phase generated voltage Vac exceeds the reference voltage V1, the comparator 4 turns on the transistor 6, the transistor 6 turns on the switching transistor 7, and the comparator 8
Turn on 2. When the rectified voltage Vc exceeds the reference voltage V2 due to the further increase of the one-phase generated voltage Vac, the transistor 80 is turned on, and the transistor 80 keeps the transistor 6 on by setting the base of the transistor 6 to the low level through the resistor r8.

When the power generation is stopped, the rectified voltage Vc is lowered, the transistor 80 is turned off, and the transistor 6 is turned off. (Embodiment 3) Another embodiment will be described with reference to FIG. However, components having similar functions to those of the first embodiment are designated by the same reference numerals.

This exciting current controller 2 is obtained by modifying the structure of the hold circuit 8 used in the exciting current controller 2 of the first embodiment. That is, the hold circuit 8 of this embodiment has a capacitor c1 that connects the output end of the comparator 4 and the base of the grounded-emitter npn transistor 80, and the base of the transistor 80 is a resistor r9.
Is grounded through. The collector of the transistor 80 is connected to the base of the transistor 6 through the base current limiting resistor r2, and the collector of the transistor 80 is grounded through the capacitor c2. Capacitor c
1 and the resistor r9 form a differentiating circuit. The resistor r1 can be omitted.

To explain the operation of this device, when the one-phase generated voltage Vac exceeds the reference voltage V1, the comparator 4 outputs a pulse voltage to the base of the transistor 80 through the capacitor c1 to temporarily turn on the transistor 80,
This turns on the transistor 6 and, at the same time, discharges the capacitor c2. The capacitor c2 is charged by the base current of the transistor 6 through the resistor r2, whereby the transistor 6 is continuously turned on, the switching transistor 7 is continuously turned on, and the exciting current is supplied to the exciting coil.

That is, if the charging time constant of the capacitor c2 is longer than one cycle of the one-phase generated voltage Vac, the transistor 80 discharges the capacitor c2 before the capacitor c2 is charged and the transistor 6 is turned off. Persistent conduction is possible. When the power generation is stopped, the transistor 80 does not turn on, the potential of the capacitor c2 becomes high level, and the transistor 6 is cut off.

FIG. 5 shows a voltage waveform diagram of each part of the exciting current control device. At the time of rotation, when the one-phase generated voltage Vac exceeds the reference voltage V1, the collector potential of the transistor 80 becomes low level (L) due to the pulse input from the comparator 4, but the transistor 8 disappears due to the disappearance of the pulse.
0 is turned off, and the capacitor c2 is charged by the base current of the transistor 6, and as a result, the transistor 6 can always be turned on when the peak voltage of the one-phase generated voltage Vac exceeds the reference voltage V1.

On the other hand, as shown in FIG. 5, when the power generation is stopped, a minute leak current flows from the battery 3 through the three-phase full-wave rectifier 12 of the generator 1, and the +
If the potential at the input end rises slowly, the transistor 80
Only one pulse is input to the base of the transistor, the transistor 80 is only turned on for a short time, the transistor 6 and the switching transistor 7 are turned on only once for a short time, and the DC power consumption can be reduced. it can. (Embodiment 4) Another embodiment will be described with reference to FIG. However, components having similar functions to those of the third embodiment are designated by the same reference numerals.

This exciting current control device 2 replaces the comparator 4 of the first embodiment with a power generation start detection circuit (power generation start determination means according to the present invention) 4a to generate a power generation start detection circuit 4a.
The hold circuit 8a for holding the power generation start signal S1 output from the
The npn emitter follower transistor (base current control switch in the present invention) 6a replaces the pnp transistor 6 of the first embodiment.

The operation will be described below. Transistor 90
Is turned on, the capacitor c4 is discharged. This turns off the transistor 80, and the base current limiting resistor r1
A base current is supplied to the emitter follower transistor 6a through 6, the transistor 6a is turned on, the switching transistor 7 is turned on, and the exciting current is supplied to the exciting coil 13.

Compared with the conventional example shown in FIG. 7, the one-phase generated voltage capable of detecting power generation is almost the same, but the diodes 101 and 102 connected to the armature coil 103, which are required in the conventional example, are not necessary. Therefore, the component structure of the generator 1 can be simplified. When the one-phase generated voltage Vac drops, the transistor 90 turns off as before and the capacitor c4 is charged through the resistor r14. However, the time constant of the integrating circuit including the capacitor c4 and the resistor r14 is set longer than the cycle of the one-phase generated voltage Vac, and the transistor 8 is set by the charging voltage of the capacitor c4.
Before 0 turns on, transistor 90 turns on again and capacitor c4 is discharged. As a result, the transistor 6a and the switching transistor 7 can be continuously conducted.

When power generation is stopped, the transistor 90 continues to be off, the potential of the capacitor c4 rises, the transistor 80 turns on, the transistor 6a turns off, the switching transistor 7 turns off, and the exciting coil 13 is energized. Be stopped. The resistors r14 and r15 need only be able to supply the base current of the small transistor 80, and can be set to a sufficiently high resistance value to reduce DC power consumption.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment.

FIG. 2 is a voltage waveform diagram of each part of the first embodiment.

FIG. 3 is a circuit diagram showing a second embodiment.

FIG. 4 is a circuit diagram showing a third embodiment.

FIG. 5 is a voltage waveform diagram of each part of the third embodiment.

FIG. 6 is a circuit diagram showing a fourth embodiment.

FIG. 7 is a circuit diagram showing a conventional excitation current control device.

[Explanation of symbols]

1 generator (self-excited AC generator) 2 Excitation current control device 3 battery 4 Comparator (power generation start determination means) 6 transistors (base current control switch) 7 switching transistors 8 hold circuit 13 Excitation coil

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields investigated (Int.Cl. ⁷ , DB name) H02P 9/08 H02J 7/16 H02P 9/14

Claims (3)

(57) [Claims] 1. A battery is connected in series with an exciting coil of an alternator having a three-phase full-wave rectifier for supplying a rectified generated current to a high end of a battery, and the high end of the battery is connected to the exciting coil.
In a magnetizing current control device for a self-excited AC generator that does not have an ignition switch , including a switching transistor for intermittently controlling the energization of the generator, the one-phase generated voltage or the neutral point voltage of the generator is 0.7V or less .
A power generation start discriminating means for outputting a power generation start signal when it exceeds a predetermined threshold level set smaller Ri, of the battery by conduction by the reception of the power generation start signal
From the high end to the control terminal of the switching transistor
The switching transistor is driven by supplying power.
Excitation current control device of a self-excited alternator, characterized in that it comprises a control switch to pass. 2. The switching transistor drive circuit
After actuation of the control switch, it causes sustain conduction of pre SL control switch, before when the 1-phase generator voltage or the neutral point voltage has dropped below a predetermined level for a predetermined time or more
Serial system excitation current control device of a self-excited alternator according to claim 1, further comprising a hold circuit for blocking the conduction of control switches. 3. The power generation start determination means is for the generator.
The one-phase generated voltage or the neutral point voltage is applied to the base electrode and
The difference between the threshold voltage and the threshold voltage
It has a differential input stage consisting of a pair of np transistors,
A claim comprising a comparator for controlling the control switch.
The exciting current control device for the self-excited AC generator according to 1 or 2.