Electricity: single generator systems – Automatic control of generator or driving means – Voltage of generator or circuit supplied
Reexamination Certificate
1999-09-20
2001-03-20
Ponomarenko, Nicholas (Department: 2834)
Electricity: single generator systems
Automatic control of generator or driving means
Voltage of generator or circuit supplied
C322S027000, C322S025000
Reexamination Certificate
active
06204643
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for electrically controlling the output of an AC generator for use in a vehicle.
2. Description of the Prior Art
FIG. 4
is a circuit diagram of a controller for a car AC generator disclosed by Japanese Laid-open Patent Application No. 7-298515. In
FIG. 4
, reference numeral
1
denotes an AC generator mounted on a vehicle, which comprises an armature coil
101
for generating an AC output and a field coil
102
driven by an unshown internal combustion engine mounted on the vehicle. Denoted by 2 is a rectifier for rectifying the AC output of the AC generator
1
, which comprises an output terminal
201
for the excitation of the field coil
102
and the voltage detection of a voltage regulator
3
and an output terminal
202
for grounding. The voltage regulator
3
is for controlling the output voltage of the AC generator
1
to a predetermined value. Reference numeral
4
represents a battery mounted on the vehicle,
5
a key switch and
6
a charging display lamp.
A description is subsequently given of the operation of the above controller. When the key switch
5
is closed at the start of the internal combustion engine, a base current is supplied from the battery
4
to a transistor
313
through the key switch
5
, the charging display lamp
6
and a fixed resistor
301
so that the transistor
313
becomes conductive. Then, the base current is supplied to a transistor
314
through a fixed resistor
302
so that the transistor
314
becomes conductive. Thereby, the base current is supplied to a transistor
321
so that the transistor
321
becomes conductive, whereby a field current runs into the field coil
101
from the battery
4
to enable the AC generator
1
to generate power. When the internal combustion engine starts operation in this state, the field coil
102
turns and the armature coil
101
generates 3-phase AC induced electromotive force.
When the AC generator
1
begins to output a 3-phase AC, the rectifier
2
rectifies the 3-phase AC and converts it into a DC. Then, the voltage regulator
3
receives the output voltage of the output terminal
201
of the rectifier
2
. When a potential divided by a fixed resistor
305
and a fixed resistor
306
exceeds a predetermined value, a zener diode
319
and a transistor
320
become conductive and a base current to the transistor
321
is cut off so that the transistor
321
becomes nonconductive, whereby a field current from the battery
4
to the field coil
102
is cutoff and the output voltage of the AC generator
1
drops.
When the output voltage of the AC generator
12
drops and the potential divided by the fixed resistor
305
and the fixed is resistor
306
falls below the predetermined value, the Zener diode
319
and the transistor
320
become nonconductive, the transistor
321
becomes conductive, a field current runs from the battery
4
to the field coil
102
, and the output voltage of the AC generator
1
rises. Thus, after the start of the internal combustion engine, the voltage regulator
3
controls the output voltage of the AC generator
1
to a predetermined value by repeating the conductive state and nonconductive state of the transistor
321
alternately.
When the charging display lamp
6
is disconnected or a display lamp drive terminal gets out of place, even if the key switch
5
is closed, the transistors
314
and
314
are both nonconductive before the start of the internal combustion engine. Therefore, the transistor
321
is nonconductive. If some residual magnetic flux is existent in the field coil
102
in this state, the AC generator
1
outputs a slight amount of voltage by the start of the internal combustion engine. When the single-phase voltage of the AC generator
1
is charged into a capacitor
317
through a fixed resistor
304
, the transistor
313
becomes conductive through fixed resistors
308
and
301
. As a result, the transistor
314
becomes conductive, the AC generator
1
outputs a normal voltage in the same manner as during the normal operation of the charging display lamp
6
, and the output voltage of the AC generator
1
is controlled to the predetermined value by the function of the voltage regulator
3
.
SUMMARY OF THE INVENTION
Since the controller for a car AC generator of the prior art is constituted as described above, when the AC generator
1
is not used for power generation for a long time and there is almost no residual magnetic flux in the field coil
102
while the charging display lamp
6
for driving the voltage regulator
3
is disconnected or the charging display lamp drive terminal gets out of place, the AC generator
1
does not start power generation even if the AC generator
1
is driven properly by the internal combustion engine.
It is therefore an object of the present invention to provide a controller for a car AC generator which enables an AC generator to generate power stably by the start of an internal combustion engine.
According to a first aspect of the present invention, there is provided a controller for a car AC generator, which comprises an AC generator driven by the internal combustion engine of a vehicle, a rectifier for rectifying the AC output of the AC generator, a battery which is charged with the rectified output of the rectifier and supplies power to the field coil of the AC generator at the start of the internal combustion engine and a voltage regulator for adjusting the output voltage of the generator to a predetermined value by controlling a field current to be supplied to the field coil from the battery intermittently, wherein the voltage regulator comprises trigger means for supplying a field current from the battery to the field coil when it detects a drop in battery voltage.
According to a second aspect of the present invention, there is provided a controller for a car AC generator, wherein the trigger means comprises means for supplying a field current from the battery to the field coil when it detects a potential difference between a reduced battery voltage and its delayed voltage.
According to a third aspect of the present invention, there is provided a controller for a car AC generator, wherein the trigger means comprises means for keeping the supply of a field current to the field coil when there is a single-phase output from the AC generator after the detection of a drop in battery voltage and cutting off a field current to the field coil after the passage of a predetermined time when there is no single-phase output from the AC generator.
According to a fourth aspect of the present invention, there is provided a controller for a car AC generator, wherein the trigger means comprises means for keeping the supply of a field current to the field coil when the frequency of the single-phase output of the AC generator is equal to or larger than a predetermined value and cutting off a field current to the field coil after the passage of a predetermined time when the frequency of the single-phase output of the AC generator is smaller than the predetermined value.
According to a fifth aspect of the present invention, there is provided a controller for a car AC generator, wherein the trigger means comprises means for making conductive a switching element for intermittently supplying a field current for a predetermined time after the detection of a drop in battery voltage.
According to a sixth aspect of the present invention, there is provided a controller for a car AC generator, wherein the trigger means is independent of other excitation circuits.
According to a seventh aspect of the present invention, there is provided a controller for a car AC generator, wherein the trigger means comprises means for annulling the function of supplying a field current to the field coil by the detection of a drop in battery voltage when there is a single-phase output from the AC generator.
According to an eighth aspect of the present invention, there is provided a controller for a car AC generator, wherein the trigger means compri
Komurasaki Keiichi
Kouwa Tatsuki
Watanabe Hirofumi
Mitsubishi Denki & Kabushiki Kaisha
Ponomarenko Nicholas
Sughrue Mion Zinn Macpeak & Seas, PLLC
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