JP2780260B2 - Vehicle charging device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle charging device, and more particularly to a vehicle charging device capable of suppressing a discharge amount of a battery even when a large electric load is used at the time of idling of a vehicle or the like. It relates to a charging device.

[Prior Art] FIG. 2 shows a change in a charging generator output current according to the number of rotations of a generator (rotor coil) connected to an engine and rotating with a rotor coil in a fully excited state.

As is known from FIG. 2, the output current of the generator rapidly decreases as its rotation speed decreases, and the maximum current value of the on-vehicle electric load is indicated by a broken line in FIG. In the range, the output current of the charging generator becomes smaller than the load current.

Therefore, in this case, constant voltage control by the regulator becomes impossible, and the battery voltage falls from the normal regulated voltage (eg, 14.5V) to almost the rated voltage of the battery (eg, 12V).

[Problems to be Solved by the Invention] Normally, since the excitation voltage of the rotor coil is supplied from a battery, a decrease in the battery voltage causes a decrease in the rotor coil excitation current and a decrease in the generator output current.
It promotes the discharge of the battery, which causes a so-called dead battery.

Therefore, the present invention solves this problem by providing a vehicle charging device that can suppress the amount of battery discharge even when a large capacity load is used during low-speed rotation of a charging generator such as when the vehicle is idling. The purpose is to provide.

Means for Solving the Problems In order to achieve the above object, the present invention provides a vehicle charging apparatus for controlling excitation of a rotor coil of a charging generator for charging a battery. Power generation control means (101, 102, 107, 103, 104, 105, 10) for interrupting the energization of the
6, 108), discharge state detecting means (109) for detecting that the battery is in a predetermined discharge state, and a booster circuit (11) for boosting the battery voltage to a voltage higher than the battery voltage.
A) a power supply circuit (112, 113, 111) for selectively supplying a battery voltage and a voltage higher than the battery voltage to the rotor coil, and a discharge state detection means for detecting a discharge state of the battery; The power supply control means (110) sets the supply voltage from the power supply circuit to a battery voltage when the discharge state is not detected, and sets the supply voltage from the power supply circuit to a voltage higher than the battery voltage when the discharge state detection means detects the discharge state of the battery. ) And technical means of a vehicle charging device.

The discharge state detection means (109) detects that the battery is in a predetermined discharge state when the operation duty of the transistor (101) for driving the rotor coil (21) is 100%, or detects the battery voltage. This is to detect that the battery is in a predetermined discharge state due to the decrease.

In the parentheses, reference numerals of the embodiments are given in order to show correspondence with the embodiments described later.

[Operation] In the vehicle charging apparatus having the above configuration, when a large-capacity electric load exceeding the output current of the charging generator is used, the battery is discharged to supply the output current shortage of the charging generator, and the battery voltage is reduced. As a result, the exciting current of the rotor coil decreases. As a result, the output current of the charging generator is further reduced, and the shortage of the current is increased.

Here, the power supply circuit includes a booster circuit and can supply a voltage higher than the battery voltage to the rotor coil,
When the discharge state detection unit detects a predetermined discharge state of the battery, the power supply control unit sets the supply voltage from the power supply circuit to the rotor coil to a voltage higher than the battery voltage,
A voltage higher than the battery voltage is applied to the rotor coil.

Thus, a sufficient exciting current is supplied to the rotor coil, and a decrease in the output current of the charging generator is avoided. As a result, the shortage of the current is suppressed to a small extent, and rapid discharge of the battery is prevented.

[Embodiment] In FIG. 1, the output voltage of a charging generator 2 for charging a vehicle-mounted battery 3 and a vehicle-mounted electric load 4 connected in parallel to the vehicle-mounted battery 3 is adjusted to a constant regulated voltage by a regulator 1.

That is, the transistor 10 provided in the regulator 1
2, Zener diode 103, resistors 104, 105, 106, 107,
The capacitor 108 forms a known constant voltage feedback circuit, and controls the operation of the transistor 101 that switches the excitation current of the charging generator rotor coil 21 to maintain the generated voltage generated in the stator coil 22 constant.

The generated voltage is converted to DC by the rectifier 23 and supplied to the battery 3 and the like.

109 is a discharge state detection circuit, and the transistor 101
Detect the collector voltage of the
A "1" level output is issued when the operation duty reaches 100%.

Reference numeral 110 denotes a control circuit which receives a one-phase voltage of the stator coil 22 to know the start of power generation, and receives a start of power generation and a "1" level output of the discharge state detection circuit 109 to provide DC / DC as a booster at a subsequent stage. Activate converter 111.

The converter 111 boosts the output voltage of the charging generator 2 to a predetermined voltage (for example, 14.5 V), and applies the boosted voltage to the rotor coil 21 via a diode 112.

The control circuit 110 has a “+” sign of the rotor coil 21.
The terminal output is fed back to accurately maintain the predetermined voltage.

The “+” terminal is connected to the output terminal of the charging generator 2 via the diode 113.

In the charging device having the above configuration, when the vehicle is running at a low speed or idling, the number of revolutions of the charging generator is small, and when a large electric load is used in this state, the output voltage of the charging generator exceeds the current supply capability, so the output voltage is no longer adjusted. Voltage (14.5
V) cannot be maintained, and almost drops to the rated voltage of the battery (12 V). For this reason, the exciting current of the rotor coil decreases, and the current supply capacity of the charging generator is further reduced and the burden on the battery increases as it is.

Here, in such a state, the operation duty of the transistor 101 should be 100%, and the discharge state detection circuit 109 starts the operation of the converter 111.

The converter 111 converts the voltage of approximately 12 V
The voltage is increased to 14.5V, and supplied to the rotor coil 21.

Thus, a decrease in the power generation capacity of the charging generator is avoided,
An increase in battery load is prevented, and the battery does not run out.

In the above embodiment, the feedback of the one-phase output of the stator coil and the output of the “+” terminal of the rotor coil to the control circuit is not always necessary.

[Effect] According to the vehicle charging apparatus of the present invention having the above-described configuration, even when an electric load exceeding the current supply capability of the charging generator is used and the battery is discharged, the excitation voltage of the rotor coil is maintained. The battery is properly maintained, and the occurrence of a dead battery due to an increase in battery load is effectively prevented.

As the battery discharge state detecting means, a means for detecting the operation duty of the transistor as in the above embodiment or a means for detecting the battery voltage (charge generator output voltage) can be considered, and both have the same effects.

[Brief description of the drawings]

FIG. 1 is an overall circuit diagram of a charging device, and FIG. 2 is a diagram showing a rotation speed dependence characteristic of a generator output current. DESCRIPTION OF SYMBOLS 1 ... Regulator 101 ... Transistor 109 ... Battery discharge state detection circuit 110 ... Control circuit 111 ... DC / DC converter (boost circuit) 2 ... Charging generator 21 ... Rotor coil 22 ... Stator coil 3 ... ... Battery 4 ... Vehicle electrical load

Claims (3)

(57) [Claims] 1. A vehicle charging apparatus for controlling excitation of a rotor coil of a charging generator for charging a battery, comprising: intermittently energizing the rotor coil according to a battery voltage to control a power generation amount of the charging generator. Power generation control means (101, 102, 107, 103, 104, 105, 106, 108), discharge state detection means (109) for detecting that the battery is in a predetermined discharge state, and battery voltage A power supply circuit (112, 113, 111) including a booster circuit (111) for boosting the voltage to a higher voltage, selectively supplying a battery voltage and a voltage higher than the battery voltage to the rotor coil; The supply voltage from the power supply circuit is used as the battery voltage when the discharging state of the battery is not detected by the detecting means, and the voltage is supplied when the discharging state of the battery is detected by the discharging state detecting means. Power supply control means for setting the supply voltage from the power supply circuit to a voltage higher than the battery voltage (11
0). 2. The discharge state detection means is set to detect that the battery is in a predetermined discharge state when an operation duty of a transistor for driving the rotor coil is 100%. The vehicle charging device according to claim 1. 3. The vehicle charging system according to claim 1, wherein said discharge state detection means is set to detect that said battery is in a predetermined discharge state by a decrease in said battery voltage. apparatus.