JP3371430B2 - Vehicle power supply - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply apparatus for a vehicle using a generator for controlling the amount of electric current supplied to a field winding to adjust the amount of electric power generated. . [0002] A generator driven by an engine is:
In recent years, it has been required that the driving torque of the generator does not rapidly increase or decrease even when the electric load suddenly increases or decreases. Therefore, when the electric load suddenly increases, it is applied to the field winding.
The field current is gradually increased by the regulator.
Thus, there is known a gradual increase control method for gradually increasing the amount of power generated by a generator . However, there is currently no way to cope with a sudden drop in electrical load. [0003] This is because the field current applied from the regulator to the field winding when the electric load suddenly decreases.
Field inductor (for example, OFF)
The field current through the flywheel diode
Field current flowing through the field winding gradually
Will be reduced to Due to this, the electric load has dropped sharply
Nevertheless, the voltage generated by the generator gradually decreases.
That is, the armature winding of the generator generates excessive electric power exceeding the demand of the electric load. Then, when this excessive power is absorbed by the battery mounted on the vehicle, there is a problem that the life of the battery is significantly shortened. An object of the present invention is to provide a vehicle power supply device that does not supply excessive power to a battery or an electric load even if an armature winding of a generator generates excessive power. . [0005] A vehicle power supply device according to the present invention generates an armature winding by controlling a battery connected to an electric load and a field current applied to the field winding. A generator for adjusting power and supplying the generated power to the battery; and a reflux diode connected in parallel to the field winding.
And over de, a regulator for controlling the field current, the
Means for detecting interruption of an electric load, and interruption of the electric load
Is detected, and the flow of the field winding is detected by the regulator.
A short-circuit circuit for short-circuiting the current generated by the generator when the duty ratio, which is the charge, is reduced . According to the present invention, the electric load suddenly decreases, and
Even if the field current applied to the magnetic winding decreases rapidly,
Since the current circulates due to the inductance , the field current flowing through the field winding gradually decreases. others
Generation of generators despite the sudden decrease in electrical load
The voltage gradually decreases, and the armature winding of the generator
Will occur. At this time, a sudden decrease state is detected,
A short circuit shorts the current generated by the generator.
This prevents excessive voltage from being applied to the battery or electrical load.
Can come off. As described above, the power supply device for a vehicle according to the present invention can reduce the current generated by the generator even when the armature winding of the generator generates excessive power. Do not short circuit and provide excessive power to the battery or electrical load. As a result,
Problems caused by application of an excessive voltage to a battery or an electric load can be eliminated. Next, a power supply device for a vehicle according to the present invention will be described with reference to an embodiment shown in the drawings. FIG. 1 is an electric circuit diagram of a vehicle power supply device showing an embodiment of the present invention. The vehicle power supply device includes a battery 3 (for example, rated 12 V), which is a vehicle power supply connected via a switch 2 to an electric load 1 of the vehicle such as a light, and an alternating current that supplies power to the electric load 1 and the battery 3. It comprises a generator 4, a regulator 5 for controlling the power generated by the generator 4, and a short-circuit 6 for short-circuiting the current generated by the generator 4 according to the state of the battery. The generator 4 is a well-known type having a Y-connected armature winding 7 and a field winding 8, and energizes the field winding 8 to connect one of the armature winding 7 and the field winding 8. , And is rotated by an engine to generate electric power in the armature winding 7. The electric power generated in the armature winding 7 is rectified by the rectifier circuit 9 and supplied to the battery 3 and the electric load 1. The regulator 5 according to the present embodiment includes a field winding 8.
The duty ratio is controlled in accordance with the battery voltage and the voltage generated by the generator 4. Specifically, the regulator 5 includes a comparison unit 11 that compares whether the battery voltage or the voltage generated by the generator 4 is a reference stored in the reference voltage unit 10. And a duty ratio control unit 12 for determining the duty ratio. The duty ratio control unit 12 compares the Hi time of the PWM signal generated by the PWM carrier generation unit 13 with the comparison unit 11
And when the duty ratio is increased, the duty ratio is gradually increased.
Further, when the duty ratio is reduced, the duty ratio is gradually reduced or rapidly reduced to zero according to the signal of the comparison unit 11. Even if the duty ratio is suddenly reduced to zero, the amount of current flowing through the field winding 8 does not suddenly decrease due to the current circulating through the flywheel diode 14 (freewheel diode) connected in parallel to the field winding 8. The duty ratio determined by the duty ratio control unit 12 is received by the base control unit 15, and the driving of the winding energizing transistor 16 (semiconductor switching element) connected to the field winding 8 is controlled, so that the field winding 8 Is controlled. The short circuit 6 comprises a command circuit 17 for detecting a battery state and giving a short circuit instruction, and a short circuit execution circuit 18 for receiving the short circuit instruction and shorting the current generated by the generator 4. In the present embodiment, the command circuit 17 detects a duty ratio, which is a control of the amount of current supplied to the field winding 8, as means for detecting the state of the battery. More specifically, a duty-zero detecting unit 19 (electricity detecting unit) for detecting that the duty ratio has become zero.
Load corresponding to a means for detecting the interruption of 1), including the duty gradual decrease detector 20 for detecting the duty ratio is gradually decreased, the short circuit indication (transistor gate control described below when one is detected (A signal for turning ON). The short circuit execution circuit 18 is connected to the generator 4
As means for short-circuiting the generated current, a thyristor trio 22 connected to each field winding 8 is provided to short-circuit the current generated in the field winding 8. The thyristor trio 22 is turned on and off by the gate control circuit 23. The gate control circuit 23 receives a short-circuit instruction from the command circuit 17 and
A signal for turning on the thyristor is supplied to each gate of the thyristor trio 22 in accordance with the battery voltage. For example, when a short circuit instruction is given and the battery voltage is 14 V or more, the thyristor trio 22 is turned on. Specifically, the gate control circuit 23 includes a gate control transistor 24, a zener diode 25 for adjusting a short-circuit voltage, and a plurality of current limiting resistors 26. Incidentally, V _CE of the gate control transistor 24 is about 1.5 V, the Zener voltage of the Zener diode 25 is set to approximately 12.5 V, even when the gate control transistor 24 is turned ON, when the battery voltage is 14V or less, The thyristor trio 22 is provided so as not to be turned on. Next, the operation of the above embodiment will be briefly described. When the switch 2 is turned on and the electric load 1 of the vehicle is large, the electric power stored in the battery 3 tends to be consumed by the electric load 1 more. Then, the regulator 5 increases the duty ratio of the regulator 5 to increase the ON time of the winding energizing transistor 16 so as to compensate for the decrease in the battery voltage, and allows a relatively large exciting current to flow through the field winding 8, Keep the battery voltage in an appropriate range (eg, 12-14.5V). Next, when the switch 2 is turned off,
When the electric load 1 rapidly decreases, the power consumption stored in the battery 3 decreases, and the battery voltage increases.
Then, the regulator 5 sets the duty ratio to zero and turns off the winding energizing transistor 16 in order to suppress the generator 4 from generating extra power. However, due to the inductance of the field winding 8, the exciting current circulates via the flywheel diode 14, and the amount of current flowing through the field winding 8 gradually decreases. Immediately after switch 2 is turned off,
Despite the rapid decrease in battery 3 consumption,
Since the generated voltage of the generator 4 gradually decreases, the generator 4 generates excessive power. As described above, when the generator 4 generates excessive power, the duty ratio of the regulator 5 is reduced to zero or decreased. At 20, a short circuit instruction is given to the gate control transistor 24, and the gate control transistor 24 is turned on. And
When the battery voltage exceeds 14 V due to excessive power generation by the generator 4, the thyristor trio 22 is turned on, and the excess current generated in the armature winding 7 is short-circuited and discharged to the ground. Is maintained at 14V. [Effects of the Embodiment] Even if the electric load 1 suddenly decreases, the amount of current flowing through the field winding 8 of the generator 4 gradually decreases, so that the driving torque of the generator 4 sharply decreases. Is eliminated. Further, even if the electric load 1 suddenly decreases, the amount of current flowing through the field winding 8 of the generator 4 gradually decreases, so that the armature winding 7 of the generator 4 generates excessive power. 6 releases excess power. For this reason, the voltage generated by the generator 4 is maintained at 14 V which is within an appropriate range of the battery 3. That is, since a high voltage is prevented from being applied to the battery 3 and the electric load 1, problems such as a short life of the battery 3 due to the application of the high voltage and a failure probability of the electric load 1 are increased. Can be eliminated. [Modification] In the above embodiment, an example is shown in which a thyristor is used as a means for short-circuiting the power generated by the generator. However, other semiconductor elements such as transistors and contact switches are switched and controlled. For example, other short-circuit means may be used. Although the example in which the current generated by the generator is short-circuited by short-circuiting the current generated by the armature winding has been described, the current generated by the generator can be reduced by short-circuiting the battery or the current applied to the battery. It may be short-circuited. By providing the current applied to the battery according to the battery voltage so as to short-circuit, when another battery is connected to the vehicle-mounted battery, the battery and the battery when the voltage applied to the battery is excessive are Protection of electric load can be performed .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an electric circuit diagram of a vehicle power supply device. [Description of Signs] 1 Electric load 3 Battery 4 Generator 6 Short circuit 7 Armature winding 8 Field winding 14 Flywheel diode (freewheel diode) 19 Duty zero detector (detects interruption of electric load )
means)

Claims (1)

(57) [Claim 1] A battery connected to an electric load and a field current applied to a field winding are controlled to adjust the power generated by the armature winding, and the generated power is controlled. A generator for supplying the battery to the battery, a reflux diode connected in parallel to the field winding, a regulator for controlling the field current, a unit for detecting interruption of the electric load, and interruption of the electric load. Detected by the regulator
The duty ratio, which is the amount of current flowing through the field winding, is reduced.
And a short circuit for short-circuiting the current generated by the generator when the power supply is turned on.