JP2720468B2 - Vehicle charge control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a battery charging control device for a vehicle, and more particularly to a battery charging control device having a high voltage load.

[Related Art] In recent years, the demand for high voltage output as well as the capacity of an electric load of an automobile has been increasing.
One method is to obtain a high voltage by boosting the voltage using a transformer. For example, the output of an AC generator for a vehicle driven by an engine is rectified to charge a battery, and on the other hand, the high-voltage output obtained by boosting the output of the generator by a transformer is rectified and applied to a high-voltage load via switch means. 2. Description of the Related Art There has been proposed a vehicle charging control device that detects a voltage and variably controls an exciting current of an AC generator to maintain a generator output.

[Problems to be Solved by the Invention] In the above-described conventional configuration, if power is intermittently applied to a high-voltage required load and control is performed, the required output to the generator fluctuates drastically, while the battery voltage is reduced. Since the change is gradual, the conventional charge control device that controls the generator output voltage by detecting the battery voltage cannot sufficiently follow the required output. Therefore, problems such as overvoltage and low voltage occur with respect to the vehicle load.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a charge control device that performs a sufficient following function even during intermittent control of a high-voltage load.

[Means for Solving the Problems] According to the present invention, a transformer for transforming an AC output of a generator, a first rectifier for rectifying the output of the transformer to obtain a DC output, Switching means connected in series with the rectifier means and the first load, second rectifier means for rectifying the AC output of the generator and supplying the rectified output to the vehicle electric load including the battery, and output of the second rectifier means. And a voltage regulator for controlling the excitation current of the generator by detecting the voltage of the generator, wherein the detection voltage of the voltage regulator is switched to the generator output side voltage when the switching means is operated. A vehicle charging control device is provided.

[Operation] When the rectified output of the AC generator is supplied to the vehicle electric load including the battery when the switching means is not operated, the battery is detected by the voltage regulator, and the exciting current of the generator is accordingly detected. Control. When the rectified DC output of the transformer output is supplied to the first load during the operation of the switching means, the voltage regulator detects the generator output side voltage,
Accordingly, the exciting current of the generator is controlled.

Embodiment FIG. 1 to FIG. 4 show an embodiment of the present invention. The same reference numerals in the drawings denote the same members. In FIG. 1, 1 is a normal vehicle alternator having a stator winding 1a, a rotor winding 1b, and a full-wave rectifier 1c, 2 is a voltage regulator, 3 is a battery, 4 is a vehicle load, and these are normal vehicles. Is the same as

Further, in order to obtain a high voltage, an alternating current is taken out from the alternating current generator 1, converted into a required voltage using a transformer 5, converted into a direct current by a rectifier, and supplied to a high voltage load 7. The control circuit 10 controls the opening and closing of the switching means 8 such as a transistor to control the power applied to the load intermittently. The high voltage load 7 is made of, for example, a transparent resistor deposited on a windshield of a vehicle. The B terminal of the voltage regulator 2 is connected to the output terminal of the battery 3, the S terminal is connected to the movable terminal of the switch 9, and the F terminal is connected to the rotor winding 1b. Controls the excitation current. According to the present embodiment, the switch 11 for instructing operation or non-operation of the high-voltage load 7 is provided.
And a switch 9 for switching and connecting the rectified output of the alternator and the battery terminal voltage to the sense terminal S of the voltage regulator 2 in conjunction therewith.

Normally (when not using a high voltage load), the voltage regulator 2
S terminal is connected to a battery as shown in the figure to control charging. Next, when a high voltage load is required and the switch 11 is turned on and the switching means 8 performs the intermittent control, the switch 9 associated with the switch 11 also switches the S terminal to the output terminal of the generator 1. As a result, the voltage regulator 2 monitors the output terminal of the generator 1 even when the output fluctuates suddenly, so that the charging can be controlled according to the change. Thus, a stable voltage can always be supplied to the battery 3 and the high-voltage load 4.

FIG. 2 shows a specific example of the voltage regulator 2. When the voltage at the terminal 2a is higher than the set voltage mainly determined by the zener diode 20, the transistor 22 is turned on, the transistor 23 is turned off, and the excitation of the rotor winding 1b is stopped to keep the output voltage of the generator 1 constant. Things. Switching means 8
The control circuit 10 controls the power supplied to the high-voltage load 7, and an example of the circuit is shown in FIG. The operation of this circuit is OP
A ramp wave is generated by the amplifier 30 (appears at one input terminal of the OP amplifier 30). This is input to the + terminal of the comparator 31. The threshold of the comparator is determined by the ratio of resistors 42 and 43. By changing this ratio, the output of the comparator 31 becomes a square wave with a different duty ratio (see FIG. 4). FIG. 4a shows the waveform of the ramp wave generated at the (-) input terminal of the OP amplifier 30, and FIG. 4b shows the output voltage waveform of the comparator 31. The power transistor 32 constituting the switching means can be turned on and off by this square wave signal to limit the power applied to the load. In addition, 24-26, 37-46
Is a resistor, 43 is a variable resistor, 21, 33 to 34 are diodes, 3
5 to 36 show each capashita.

As described above, the first switching switch 9 is connected to the voltage regulator 2.
A switch for switching the connection location of the S terminal switches between the battery and the output terminal of the generator 1. The switch 9 works in conjunction with the switch 11, and when the switch 11 in the figure is turned off, the switch 9 connects the movable terminal to the battery side, and when turned on, connects the movable terminal to the generator side.

The overall operation will be described. During normal operation, that is, when the operation of the high-voltage load 7 is not required, the switch 9 connects the movable terminal in the figure to the battery side in conjunction with the turning off of the switch 11, monitors this voltage and monitors the output of the generator 1. Control the voltage. When the operation of the high-voltage load 7 is required, the switch 11 is turned on to turn on and off the power transistor 32 so that the required power is supplied to the load 7, that is, the average power matches the required value. Control to change the time ratio of
At this time, from the viewpoint of the generator 1, a large load that requires power equivalent to the power generated by the generator is connected or disconnected. At this time, if the voltage is monitored by a battery, the battery can be regarded as a capacitor having a large capacity, so that the change in the battery voltage is slower than the load fluctuation and the response of the transformer 5. Therefore, it cannot follow the intermittent operation of the switching means 8. Therefore, if the connection of the S terminal to the output terminal of the generator 1 is changed by the switching switch 9 linked with the ON operation of the switch 11, the fluctuation of the generator 1 can be followed.

As another embodiment, in FIG. 1, the output is taken out using voltage conversion by a transformer, but the load of the generator need not be limited to the transformer. Therefore, the present invention can be used when the load of the generator fluctuates at high speed due to intermittent control or the like.

[Effect] When power is supplied to a low-speed fluctuating load such as a battery by an AC generator for a vehicle, the generator exciting current is controlled in accordance with the battery terminal voltage. By controlling the generator exciting current in response, power can be supplied with a generator output that matches the load fluctuation, following the load fluctuation speed.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of an embodiment of the present invention, FIG. 2 is a circuit diagram of the voltage regulator in FIG. 1, and FIG.
FIG. 4 is a connection diagram of the switching means and the control circuit in FIG. 1, and FIGS. 4a and 4b are waveform diagrams of the main parts in FIG. 1: generator (1a: stator winding, 1b: rotor winding, 1c: full-wave rectifier), 2: voltage regulator, 3: battery, 4: vehicle load, 5:
Transformer, 6: High voltage rectifier, 7: High voltage load, 8: Switching means, 9: Switching switch, 10: Control circuit, 11: Switch

Claims (1)

(57) [Claims] 1. A transformer for transforming an AC output of an AC generator for a vehicle, a first rectifier for rectifying the output of the transformer to obtain a DC output, a first rectifier and a first load. A switching means connected in series with the power supply, a second rectification means for rectifying an AC output of the generator and supplying the rectified output to a vehicle electric load including a battery, and detecting a battery voltage or an output voltage of the second rectification means. A voltage regulator for controlling the excitation current of the generator by switching the voltage to be detected by the voltage regulator to the output voltage of the second rectifier when the switching means is operating and to the battery voltage when not operating. Charging control device for a vehicle, comprising: