Battery charging apparatus

Details Battery charging apparatus Battery charging apparatus

2001-02-09

2002-03-26

Toatley, Gregory (Department: 2838)

Electricity: battery or capacitor charging or discharging

Battery or cell charging

With detection of current or voltage amplitude

C320S152000, C320S153000, C320S162000, C320S163000

Reexamination Certificate

active

06362603

ABSTRACT:

TECHNICAL FIELD OF THE INVENTION
This invention pertains to a battery charging apparatus for charging a battery by a rectified output from a magneto generator driven by a primer such as an internal combustion engine and so on.
BACKGROUND OF THE INVENTION
The battery charging apparatus mounted on a motor bicycle or the like driven by an internal combustion engine comprises a magneto generator driven by the internal combustion engine, a rectifier circuit having input terminals connected to output terminals of the generator and output terminals between which the battery is connected, an output short circuit having on-off controllable switch elements to short the output terminals of the magneto generator when the switch elements are at an on-state and a controller to control the switch elements of the output short circuit in accordance with an output voltage of the battery.
An example of the prior art battery charging apparatus is shown in
FIG. 3. A
magneto generator
1
generates an AC voltage by being driven by an internal combustion engine mounted on a vehicle such as a motor bicycle or the like. The magneto generator
1
comprises a not shown magnet rotor mounted on a crankshaft of the internal combustion engine and a stator having three phase generation coils Lu through Lw.
A rectifier circuit
2
to rectify an output of the generator
1
comprises a three-phase bridge circuit of diodes Du through Dw and Dx through Dz connected to each other in a bridged manner. AC input terminals
2
u
through
2
w
of the rectifier circuit
2
are formed of respective connection points of the diodes Du through Dw for an upper arm of the bridge circuit and the diodes Dx through Dz for a lower arm of the bridge circuit while positive and negative DC output terminals
2
p
and
2
n
of the rectifier circuit
2
are formed of the common connection point of the cathodes of the upper arm diodes and the common connection point of the anodes of the lower arm diodes, respectively. The AC three-phase input terminals
2
u
through
2
w
of the rectifier circuit
2
are connected to the output terminals
1
u
through
1
w
of the generator, respectively, while the battery
3
is connected across the DC output terminals
2
p
and
2
n
of the rectifier circuit
2
.
A load
4
is connected through a power source switch
5
to both ends of the battery
3
. An overvoltage detection circuit
6
serves to detect a terminal voltage of the battery
3
to generate an overvoltage detection signal when an instantaneous value of the detected terminal voltage exceeds a set value.
Thyristors Thu through Thw serve as output shorting switch elements with cathodes thereof commonly connected to the negative output terminals of the rectifier circuit
2
and with anodes thereof connected to the AC input terminals
2
u
through
2
w
of the rectifier circuit
2
, respectively.
In this example, an output short circuit is formed by the diodes Dx through Dz and the thyristors Thu through Thw. When control signals are applied to the thyristors Thu through Thw, the thyristors having forward voltages applied across the anode and cathode thereof among these thyristors become an on-state and the generator is shorted between the output terminals
1
u
and
1
v
,
1
v
and
1
w
and
1
w
and
1
u
of the U, V and W phases of the generator through the on-state thyristors and the diodes Dx through Dz.
The overvoltage detection circuit
6
comprises a voltage divider circuit formed of a series circuit of a first divider resistor R
1
, a Zener diode ZD
1
and a second voltage divider circuit R
2
and connected in parallel to both sides of the battery
3
with the cathode of the Zener diode ZD
1
directed to the positive side of the battery
3
. The overvoltage detection circuit
6
conducts the Zener diode ZD
1
when the instantaneous value of the terminal voltage of the battery
3
exceeds the set value to generate an overvoltage detection signal.
To the connection point of the resistor R
1
and the Zener diode ZD
1
of the overvoltage detection circuit
6
is connected a base of a PNP transistor TR
1
having an emitter connected to the DC output terminals
2
p
of the rectifier circuit
2
while a collector of the transistor TR
1
is connected through resistors Ru through Rw to gates of the thyristors Thu through Thw.
In this example, a switch trigger circuit
7
that applies to the respective thyristors trigger signals for conducting the thyristors Thu through Thw comprises the transistor TR
1
and the resistors Ru through Rw. The switch trigger circuit
7
applies the trigger signals to the thyristors Thu through Thw when the terminal voltage of the battery exceeds the set value and thereby the Zener diode ZD
1
is turned on to apply the trigger signals to the thyristors Thu through Thw.
In the example of
FIG. 3
, a regulator circuit
8
having a rectifying function and a voltage regulating function is constituted by the rectifier circuit
2
, the output short circuit comprising the low arm diodes Dx through Dz of the bridge of the rectifier circuit
2
and the thyristors Thu through Thw, the overvoltage detection circuit
6
and the switch element trigger circuit
7
. The regulating circuit
8
and the generator
1
constitutes the battery charging apparatus.
In the battery charging apparatus shown in
FIG. 3
, the DC voltage is applied to the battery
3
from the generator
1
through the rectifier circuit
2
to thereby charge the battery
3
. The DC voltage (the battery terminal voltage) applied from the rectifier circuit
2
to the battery includes a ripple voltage having a waveform corresponding to that of the AC voltage output from the generator
1
. The overvoltage detection circuit
6
applies the trigger signals to the thyristors Thu through Thw when the instantaneous value of the battery terminal voltage including the ripple voltage exceeds the set value.
As the instantaneous value of the terminal voltage of the battery
3
is equal to or less than the set value, the transistor TR
1
turns into an off-state because the Zener diode ZD
1
of the overvoltage detection circuit
6
is at a nonconductive state and therefore the thyristors Thu through Thw are at an off-state. In these states, the output of the generator
1
is rectified by the rectifier circuit
2
and supplied to the battery
3
so that it is charged. Since the power source switch
5
is closed during the operation of the internal combustion engine, the electric power is supplied from the battery to the load
4
.
As the instantaneous value of the terminal voltage of the battery
3
exceeds the set value, the Zener diode ZD
1
gets turned on so that the transistor TR
1
becomes the on-state because of the base current flowing through the transistor TR
1
and as a result, the trigger signals are applied from the battery
3
through the transistor TR
1
to the thyristors Thu through Thw. At that time, the thyristors Thu through Thw are conducted while the forward voltages are applied between the anodes and the cathodes thereof and the output terminals of the generator
1
are shorted through either of the conducting thyristors and the lower arm diodes Dx through Dz of the bridge of the rectifier circuit
2
. For instance, the thyristor Thu is at the on-state while the output terminal
1
u
of the generator
1
is at high potential relative to the other output terminals
1
v
and
1
w
. At that time, the output terminals
1
u
and
1
v
of the generator
1
are shorted through the thyristor Thu and the diode Dy and the output terminals
1
u
and
1
w
of the generator
1
are shorted through the thyristor Thu and the diode Dz.
In this manner, since the voltage is never applied from the generator
1
to the rectifier circuit
2
while the output terminals of the generator
1
are shorted, the charging current is prevented from flowing from the rectifier circuit
2
to the battery so that the terminal voltage of the battery is lowered. As the terminal voltage of the battery
3
is equal to or less than the set value, the Zener diode ZD
1
becomes the nonconducti

Affiliated with

Also associated with

Rating

Battery charging apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Battery charging apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Battery charging apparatus will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2870963