JP3149521B2 - Voltage generator for vehicle generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage regulator for a vehicle generator.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 62-894 filed by the present applicant.
Japanese Patent Application Publication No. 34-34139 discloses a method for controlling an intermittent load based on a function (for example, an average value thereof) of a duty ratio immediately before an intermittent load is applied and a maximum duty ratio of an exciting current at an initial stage of the intermittent load driving. By fixing the duty ratio of the exciting current after the initial stage, the fluctuation of the engine load during the intermittent load driving is suppressed.

[0003]

However, in the above-mentioned prior art, it is possible to reduce the fluctuation of the load of the generator and the fluctuation of the rotation speed of the engine. However, there is a disadvantage that the generated voltage fluctuates in synchronization with the cycle of the intermittent load. was there. That is, the output current of the generator excited at the fixed duty ratio is constant (accurately, the output power is constant, but the voltage change is small, so the output current can be regarded as constant). During the period when power is supplied to the battery, the charge current of the battery decreases (or the discharge current increases) and the terminal voltage of the battery decreases. During the period when power is not supplied to the intermittent load, the charge current of the battery increases (or the discharge current decreases). As the terminal voltage of the battery rises, the terminal voltage of the battery (substantially equal to the generated voltage) fluctuates in synchronization with the intermittent operation of the intermittent load.

When the power generation voltage fluctuates, the illuminance of a lamp or the like fluctuates, and the power supply voltage of various other devices fluctuates. In addition, the above-mentioned conventional apparatus requires a storage means, which complicates the apparatus configuration. Further, even when another intermittent load is driven during a certain intermittent load driving period, the maximum duty ratio to be stored is not sufficient. There were drawbacks that were appropriate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a voltage regulator for a vehicular generator capable of suppressing fluctuations in engine load during intermittent load driving and reducing voltage fluctuations. That is the purpose.

[0006]

According to the present invention, there is provided a voltage adjusting apparatus for a vehicle generator, comprising: a switch for intermittently controlling an exciting current of the vehicle generator for supplying power to a battery and a load; A duty ratio determining means for determining a duty ratio of the intermittent control based on a difference between an input voltage to be applied and a predetermined set voltage, and an intermittent load input detecting means for detecting input of an intermittent operation load. In the voltage adjusting device for a generator, the duty ratio determining means includes a first set value setting means for setting the set voltage to a first set value when the intermittent operation load is not turned on, and a duty cycle of the intermittent operation load. Second set value setting means for setting the set voltage to a second set value lower than the first set value at the time of turning on, and an input voltage for setting the input voltage to an average value of the battery terminal voltage at the time of turning on the intermittent operation load. It is characterized by comprising a value setting means.

[0007]

The duty ratio determining means of the voltage regulator determines the duty ratio based on the difference between the input voltage related to the terminal voltage of the battery and a predetermined set voltage. The switching means of the voltage regulator intermittently controls the exciting current of the vehicle generator for supplying power to the battery and the load at the duty ratio. The intermittent load input detecting means of the voltage regulator detects the input of the intermittent operation load. In particular, the duty ratio determining means includes a first set value setting means, a second set value setting means, and an input voltage value setting means.

The first set value setting means sets the set voltage to the first set value when the intermittent operation load is not turned on. The second set value setting means sets the set voltage to a second set value lower than the first set value when the intermittent operation load is applied. The input voltage value setting means sets the input voltage to the average value of the battery terminal voltages when the intermittent operation load is turned on.

[0009]

As described above, the voltage regulator for a vehicle generator according to the present invention reduces the set voltage when the intermittent operation load is applied and reduces the exciting current so that the average battery terminal voltage becomes the set voltage. Because it controls intermittently,
The following effects can be obtained.

(A) During intermittent load driving, fluctuations in engine load and voltage fluctuations are suppressed. That is, by setting the input voltage to the average value of the battery terminal voltages, it is possible to suppress fluctuations in the exciting current and, consequently, fluctuations in the engine load, and reduce the set voltage to the second set value to reduce the internal impedance of the battery.
Thereby, the voltage drop inside the battery is reduced, and the fluctuation of the battery terminal voltage due to the charge / discharge of the battery is suppressed.

(B) Since the duty ratio is not determined by the maximum duty ratio at the beginning of the intermittent load driving and the duty ratio immediately before the driving of the intermittent load as in the prior art, the duty ratio after the start of the intermittent load driving is determined. The duty ratio can follow the change in the average voltage, and can cope with the change in the magnitude of the intermittent load.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) An embodiment of a voltage regulator for a vehicle generator according to the present invention will be described below with reference to FIG. A three-phase AC generator (vehicle generator in the present invention) 1 driven by a vehicle engine (not shown) and including a stator coil 11, a three-phase full-wave rectifier 12, and a field coil 13 is provided with a predetermined power. The rectified voltage is applied to the high terminal of the battery 3 and to one end of the intermittent load 6 through the switch 5. The lower terminal of the battery 3 and the other end of the intermittent load 6 are grounded. The intermittent load 6 is a load interrupted every several seconds, such as a turn signal or a hazard lamp.

The voltage adjusting apparatus according to this embodiment includes a duty ratio determining section (duty ratio determining means and intermittent load input detecting means in the present invention) 2 and a switch section (switch means in the present invention) 14. Consists of The duty ratio determining section 2 includes a voltage detecting section 21, a first voltage comparing section (first setting value setting means in the present invention) 22, and a voltage smoothing section (input voltage value setting means in the present invention) 23. A second voltage comparing section (second set value setting means in the present invention) 24, an intermittent load input detecting section (intermittent load input detecting means in the present invention) 25, and a duo.
A voltage detecting unit 21, a first voltage comparing unit 22, a voltage smoothing unit 23, and a second voltage comparing unit 2.
4. The duty ratio signal selecting section 26 is the duty ratio
Tee ratio determining means.

The voltage detector 21 detects the terminal voltage V of the battery 3.
t, and outputs a divided voltage of the terminal voltage Vt. The first voltage comparator 22 compares the divided voltage with a predetermined first set value and outputs a comparison output to the duty ratio signal selector 26. The input voltage value setting unit 23 outputs the average value of the divided voltages to the second voltage comparison unit 24. The second voltage comparator 24 compares the second set value smaller than the first set value with the average value of the divided voltages and outputs a comparison output to the duty ratio signal selector 26. The intermittent load input detecting unit 25 detects a potential change at one end of the intermittent load 6 and detects whether the intermittent load 6 is input. The duty ratio signal selecting section 26 outputs the output of the first voltage comparing section 22 to the switch section 14 when the intermittent load is not applied, based on the output signal of the intermittent load input detecting section 25, and outputs the second voltage when the intermittent load is applied. The output of the comparison unit 24 is output to the switch unit 14.

The switch section 14 includes a first-stage transistor 140 having a grounded emitter for inputting the output voltage of the duty ratio signal selection section 26 to the base through a base resistor rb, a collector resistance rc of the first-stage transistor 140, and a first-stage transistor at the base. It comprises a grounded drive transistor 141 to which a collector voltage of 140 is input and a backflow prevention diode d connected in parallel with the field coil 13. The high terminal voltage of the battery 3 is
And the first-stage transistor 140 through the collector resistance rc
To the collector. Drive transistor 141
Are connected to the higher end of the stator coil 11 and the higher terminal of the battery 3 through the field coil 13.

FIG. 2 shows a specific circuit example of the duty ratio determining unit 2.
And its operation will be described. Voltage detector 21
Is applied to the + input terminal of the comparator 221 as the first voltage comparison unit 22, and the divided voltage Vs of the terminal voltage Vt of the battery 3 generated at the connection contact of the series resistors 211 and 212 is connected to the-input terminal. One set value Vr1 is input.

As a result, the comparator 221 outputs the divided voltage V
when s is greater than the first set value Vr1,
When the partial pressure Vs is smaller than the first set value Vr1, a low level is output. The partial pressure Vs is the voltage follower 23.
1, the voltage is input to an integration circuit (input voltage value setting means 23) including a resistor 232 and a capacitor 233, is converted to an average voltage Vsdc, and is applied to a + input terminal of a comparator 241 as a second voltage comparison unit 24. The second setting value Vr2 is input to the input terminal; Here, the second set value Vr2 is a predetermined value lower than the first set value Vr1. As a result, the comparator 241 outputs the average voltage Vs
A high level is output when dc is larger than the second set value Vr2, and a low level is output when the average voltage Vsdc is smaller than the second set value Vr2.

The intermittent load input detecting section 25 comprises a constant voltage diode 252 to which the high terminal voltage Vm of the intermittent load 6 is applied to the cathode through a resistor 251, and the anode of the constant voltage diode 252 is grounded. The cathode voltage Vm ′ of the constant voltage diode 252 is output to the duty ratio signal selector 26 as the output voltage of the intermittent load input detector 25. The cathode voltage Vm ′ is at a high level when power is supplied to the intermittent load 6, and is at a low level when power is not supplied. The constant voltage diode 252 prohibits the output voltage of the intermittent load input detecting unit 25 from rising above a certain level.

The duty ratio signal selector 26 includes an inverter 261, AND circuits 262 and 263, and a diode 26.
4,265. The cathode voltage Vm ′ inverted by the inverter 261 is input to the AND circuit 262, and the cathode voltage Vm ′ is directly input to the AND circuit 263. As a result, when the power is not supplied to the intermittent load 6, the comparator 221 Output of diode 2
The output from the comparator 241 is output to the input terminal of the switch unit 14 through the diode 265 when the power is supplied to the intermittent load 6.

As a result, the duty ratio determining unit 2 controls the duty ratio of the exciting current so that the terminal voltage of the battery 3 becomes the first set value Vr1 when the intermittent load 6 is not driven, and When the load 6 is driven, control is performed so that the average value of the terminal voltage of the battery 3 becomes the second set value Vr2. here,
The CR time constant of the integration circuit (input voltage value setting means 23) composed of the resistor 232 and the capacitor 233 is set to be several times or more the period of the intermittent load, whereby the ripple of the average voltage Vsdc due to the intermittent load 6 is sufficiently reduced. Has been reduced.

Since the internal impedance of the battery 3 increases as it is charged as shown in FIG. 3 and the potential becomes higher, the second set value Vr2 is set within the range where the operation of the vehicle is not hindered. Thus, the internal impedance of the battery 3 is reduced, and as a result, the change in the internal voltage drop of the battery 3 when the battery 3 is charged and discharged due to the intermittent load 6 can be reduced.

FIG. 3 shows a preferred value of the second set value Vr2.
The characteristic line L in FIG. 3 shows the relationship between the terminal voltage Vt of the battery 3 and the current I flowing into and out of the terminal. In this embodiment, as the second set value Vr2, the open terminal voltage point of the battery 3 (the point at which the charge / discharge current is zero, 11.8 to 12.8 V for a normal vehicle battery) B is employed. Incidentally, the point A on the characteristic line L is the first set value Vr1, which is equal to the conventional set value. Therefore, in the conventional device, the intermittent load 6
Also at the time of driving, the current fluctuates by ΔI around the point A in synchronization with the intermittent operation of the intermittent load 6, and the terminal voltage of the battery 3 fluctuates by ΔV1 accordingly.

On the other hand, in the present invention, the open terminal voltage point B of the battery 3 is adopted as the second set value Vr2.
In the same current fluctuation ΔI (precisely, the current fluctuation ΔI slightly decreases in accordance with the voltage drop of the battery 3), the terminal voltage of the battery 3 changes by ΔV2. ΔV2 is ΔV
Since it is smaller than 1, it is clear that the voltage fluctuation during intermittent load driving can be suppressed as a result. Incidentally, if the charge level of the battery 3 is allowed to decrease, it is possible to select a lower battery terminal voltage as the second set value Vr2 as shown at a point C in FIG.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a voltage regulator for a vehicle generator according to the present invention;

FIG. 2 is a circuit diagram showing a specific circuit example of a duty ratio determining unit in FIG. 2;

FIG. 3 is a voltage-current characteristic diagram of a battery,

[Explanation of symbols]

1 is a generator, 2 is a duty ratio determining unit (duty ratio determining means, a part of the voltage regulator), 14 is a switch unit (switch means, the rest of the voltage regulator), 3 is A battery, 6 an intermittent load, 22 a first voltage comparison unit (second set value setting means), 23 a voltage smoothing unit (input voltage value setting means), and 24 a second voltage comparison unit (second set value setting means) ), 25 are intermittent load input detecting units (intermittent load input detecting means).

Claims (1)

(57) [Claims] A switch for intermittently controlling an exciting current of a vehicle generator for supplying power to a battery and a load; and an intermittent control based on a difference between a predetermined voltage and an input voltage related to a terminal voltage of the battery. A duty ratio determining means for determining the duty ratio of the vehicle, and an intermittent load input detecting means for detecting the input of the intermittent operation load, wherein the duty ratio determining means comprises: A first set value setting means for setting the set voltage to a first set value when the intermittent operation load is not turned on, and a second set value lower than the first set value when the intermittent operation load is turned on And an input voltage value setting means for setting the input voltage to an average value of the battery terminal voltage when the intermittent operation load is applied. Pressure regulator.