JPH03117400A - Controller for ac generator for vehicle - Google Patents

Abstract

PURPOSE:To relieve load to be applied on a drive source through lowering of input torque and to operate a load having high power consumption through lowering of output current by providing means for making ineffective the field current control through a field current regulating means. CONSTITUTION:When the rotation of a generator exceeds over a preset value, voltage Vc to be applied on the inverted input terminal of a comparator 30 goes higher than the divided voltage Vd at the non-inverted input terminal and thereby the voltage at the output terminal of the comparator 30 goes to zero. Since the output from a comparator 23 is interrupted, transistor 28 is maintained in OFF. state. Consequently, when the rotation of the generator exceeds over the preset value, control of field current according to the temperature of stator winding is not carried out by the comparator 23.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a control device for a vehicle alternator, and more particularly to an IO control device for controlling an alternator mounted on a vehicle.

[Prior Art] Generally, an alternating current generator mounted on a vehicle is controlled by a control device to supply power to each load and battery of the vehicle. As shown in Figure 4, the input torque required to drive the alternator and the output current of the generator change depending on the rotation speed, and as is already known, the respective characteristic curves change depending on the temperature. It changes accordingly. In other words, the input torque of the generator has a characteristic that it gradually decreases from a cold characteristic curve immediately after the start of power generation to a hot characteristic curve as the generator self-heats and the ambient temperature rises. . or,
Along with this, the output current also shifts (decreases) from the cold characteristic curve to the hot characteristic curve.

However, as mentioned above, when it is cold, a larger input torque is required than when it is hot, so for example, when driving a generator with a hydraulic pump, a hydraulic pump that can cover the large input torque when it is cold is required.
There was a problem that the drive source became large.

Furthermore, when an alternator is driven by an internal combustion engine for running a vehicle, the rotation of the internal combustion engine becomes unstable due to the large input torque, which is not favorable for the running of the vehicle, and fuel consumption Wffi also increases. There is a problem with putting it away.

Therefore, a control device for a vehicle AC generator described in Japanese Patent Application Laid-Open No. 62-104500 detects the field current flowing in the field winding of the generator and converts the field current into the cold state. Also proposed is a system in which the input torque is reduced by controlling it so that it corresponds to the hot part.

[Problems to be Solved by the Invention] However, even if the maximum value of the field current is controlled to a value equivalent to the hot part as in the above-mentioned generator, the output current will be larger in the cold period than in the hot part. , it is not possible to reduce the input torque in the cold state to the same extent as the input torque in the hot part. Therefore, with this generator, it has not been possible to completely eliminate the above-mentioned problems such as unstable rotation of the internal combustion engine.

Also, in cold weather, there are many opportunities to use loads with large power consumption, such as defrosting heaters, etc., but the input torque can be lowered by controlling the hot part like the generator mentioned above. The disadvantage is that the output current also decreases, and the load cannot be fully operated due to the lack of output current.

An object of the present invention is to provide a control device for a vehicle alternator that can reduce the input torque as appropriate to reduce the load applied to the drive source, and prevent a drop in output current to operate a load with large power consumption. Our goal is to provide the following.

[Means for Solving the Problems 1] The present invention includes an alternator mounted on a vehicle, and a field current of the alternator is controlled based on the battery voltage of the vehicle,
a voltage adjusting means for adjusting the output voltage; a temperature detecting means for detecting the temperature of the alternator; and an alternating current controlled by the voltage adjusting means when the temperature detected by the temperature detecting means is low. In a control device for a vehicle alternator comprising a field current adjusting means for controlling a field current of the generator based on its temperature, a disabler for appropriately disabling control of the field current by the field current adjusting means. The gist of the present invention is a control device for a vehicle alternator equipped with a means for converting.

[Function] Therefore, when the generator is cold, such as immediately after the start of power generation, the temperature detection means detects that the temperature of the generator is low, and the field current adjustment means controls the field current based on the temperature at that time.

Generally, the input torque required to drive a generator is
The amount of heat generated during the cold state described above is greater than that of the hot portion where the stator windings and the like generate heat due to continued power generation. Therefore, as described above, since the field current is reduced by υ1'#J, the input torque is reduced, and the load on the drive source of the alternator is accordingly reduced.

Moreover, the control of the field current by the field current adjusting means can be appropriately regulated by the nullifying means.

Therefore, for example, when the rotational speed of the generator is higher than the set rotational speed and the generator is cold, the output current of the alternator can be increased by not controlling the field current by the field current adjusting means.

[Example 1] An example embodying the present invention will be described below with reference to the drawings.

FIG. 1 is an electrical circuit diagram showing the overall configuration of the control device of this embodiment. As shown in the figure, a generator 1 is driven by an internal combustion engine (not shown) for running a vehicle, and is composed of a stator winding 2 and a field winding 3 that are star-connected. The AC output of the generator 1 is full-wave rectified by a full-wave rectifier circuit 5 composed of diodes 4a to 4f, and the DC power is supplied from the output terminal 6 to the field winding 3 and the load 9 of the vehicle, and also to the battery. It is designed to charge 10. The other end of the field winding 3 is connected to an input part F of a field current control circuit 11 to be described later, and a flywheel diode 12 is connected in parallel to the field winding 3. It is designed to absorb surges caused by intermittent connections.

A thermistor 13 as a temperature detection means is attached to the stator winding 2, and its resistance value changes depending on the temperature of the stator winding 2, that is, the heat generation temperature of the alternator 1. One end of this thermistor 13 is grounded, and the other end is connected to the input section R of the field current control circuit 11.

FIG. 2 is an electric circuit diagram showing details of the field current control circuit 11. As shown in the figure, the voltage regulator 14 is connected to the battery 10 via an input section S and an input section A, and is also connected to the base of a transistor 15. Further, the collector of the transistor 15 is connected to the field winding 3 via the input section F.

The voltage regulator 14 and the transistor 15 constitute voltage regulating means, and when the battery voltage applied via the input section S is less than a predetermined value, the battery voltage from the input section A is applied to the base of the transistor 15. and turn it on. Also, when the battery voltage is above a predetermined value, transistor 1
Keep 5 off. Therefore, when the voltage of the battery 10 is low (the remaining capacity is low), the transistor 15 is turned on and current flows through the field winding 3, and the battery 10 is charged by the output voltage of the generator 1. When the voltage is high and there is much remaining power, the transistor 15 is turned off, so that no current flows through the field winding 3 and charging of the battery 10 is stopped.

Further, the thermistor 13 is connected to the battery 10 via the input section R1 resistor 16 and the input section A, and
It is connected to the inverting input terminal of the amplifier 18 via the resistor 17, and the divided potential between the thermistor 13 and the resistor 16, that is, the potential at the connection point a of the resistor 16.17 is applied to the inverting input terminal. There is. Further, resistors 19 and 20 are connected in parallel to the thermistor 13 and the resistor 16, and the connection point thereof is connected to the non-inverting input terminal of the amplifier 18 via the resistor 21. Therefore, the divided potential of resistors 19 and 20 is applied to the non-inverting input terminal.

Further, negative feedback is applied to the amplifier 18 via a resistor 22.

When the temperature of the stator winding 2 is low (cold time),
Since the resistance value of the thermistor 13 is low, the voltage applied to the inverting input terminal of the amplifier 18 is low, and the output voltage Va of the amplifier 18 is high. On the other hand, when the temperature of the stator winding 2 is high, the resistance of the thermistor 13 becomes high, so the voltage applied to the inverting input terminal of the amplifier 18 becomes high, and the output voltage Va of the amplifier 18 becomes low.

A smoothing circuit 26 consisting of a resistor 24 and a capacitor 25 has one end of the resistor 24 connected to the field winding 1i13 via the input part F, and conducts the field winding 3 at the charging voltage vb charged to the capacitor 25. In other words, a value approximate to the field current is detected.

Note that when the transistor 15 in the voltage regulator 14 is on, the input part F is grounded, and the capacitor 2
The voltage of 5 is oV.

The comparator 23 inputs the output voltage Va of the amplifier 18 to its non-inverting input terminal, and inputs the charging voltage vb of the capacitor 25 of the smoothing circuit 26 to its inverting input terminal. Further, the output terminal of the comparator 23 is connected to the base of a transistor 28 via a resistor 27.
The collector of is connected to the base of the transistor 15.

In this embodiment, the resistors 16, 17.19 to 22.2
7, an amplifier 18, a comparator 23, a smoothing circuit 26, a transistor 28, etc. constitute a field current adjusting means.

Then, the comparator 23 receives the charging voltage vb from the smoothing circuit 26.
and the output voltage Va from the amplifier 18, and when the output voltage Va is high, the transistor 28 is turned on, and when the charging voltage Vb is high, the transistor 28 is turned off. When transistor 28 is turned on, voltage application from voltage regulator 14 to transistor 15 is regulated, and transistor 15 is turned off. Therefore, the transistor 28 forcibly turns off the transistor 15 which is turned on by the voltage regulator 14.

Here, suppose that the transistor 15 in the voltage regulator 14 is turned on, and the output voltage Va is the charging voltage Vb, (=
O), the comparator 23 turns on the transistor 28, so that the transistor 14 is forced off and the field current in the field winding 3 is interrupted. Then, the charging voltage vb of the capacitor 25 of the smoothing circuit 26 increases accordingly and becomes higher than the output voltage Va. As a result, the transistor 28 is turned off in the comparator 23, and the transistor 1
As transistor 5 turns on, the field current flows again to transistor 1.
It flows to 5. When transistor 15 is turned on, capacitor 25 is discharged, charging voltage vb becomes lower than output voltage Va, transistor 15 is forcibly turned off again, and the field current is cut off. In this way, the transistor 15 repeats on/off operations, and the field current is repeatedly turned on and off accordingly.

The conductivity of the transistor 15 described above is the same as that of the amplifier 1.
It changes according to the output voltage Va from 8.

That is, when it is cold and the output voltage va is high, the conductivity of the transistor 28 is high, and conversely the conductivity of the transistor 15 is low. Therefore, in this case, the field current is controlled by the voltage regulator 14 described above. On the other hand, when it is a hot part and the output voltage Va is always lower than the charging voltage Vb, the comparator 23 keeps the transistor 2 in an off state. Therefore, the transistor 15 is not forcibly turned off and is normally controlled by the voltage regulator 14 based on the battery voltage.

An F/V converter (frequency/voltage converter) 29 is connected to the connection point 8 of the diodes 4a and 4d of the full-wave rectifier circuit 5 via the input part P, and is connected to the connection point 8 of the stator winding 2 of the alternator 1.
Input the phase AC voltage.

The F/V converter 29 generates a voltage Vc proportional to the frequency of the output voltage from one phase of the generator 1 (the rotational speed of the generator 1).
is applied to the inverting input terminal of comparator 30.

Further, the non-inverting input terminal of the comparator 30 is connected to the connection point C between the resistors 31 and 32 connected to the battery 10 via the input section A, and the divided potential Vd of both resistors 31 and 32 is applied. It looks like this. Further, the output terminal of the comparator 30 is connected to the base of the transistor 28 via a reverse current prevention diode 33. In this embodiment, this divided potential Vd is set to i? When the rotation speed of 11 is the preset N1,
It is set to have the same value as the voltage Vc output from the F/V converter 29 to the inverting input terminal of the comparator 3o.

Therefore, when the rotational speed of the generator 1 is N1 or less, the divided potential Vd is always higher than the voltage Vc, so the comparator 30 connects the backflow prevention diode 33 with a high potential output voltage to the output terminal.
applied to the cathode of Conversely, when the rotational speed of the generator 1 exceeds N1, the voltage Vc applied to the inverting input terminal of the comparator 30 becomes higher than the divided potential Vc of the non-inverting input terminal, so the output terminal of the comparator 30 becomes 0. ■It becomes. Therefore, at this time, the output of the comparator 23 is cut off, and the transistor 28 is kept in an off state. As a result, when the rotation speed of the generator 1 exceeds N1, the comparator 2 described above
3, the field current is not controlled according to the temperature of the stator winding 2.

In this embodiment, the F/V converter 29 constitutes rotational speed detection means, and the comparator 30 constitutes invalidation means.

Next, the operation of the control device for a vehicle alternator configured as described above will be explained with reference to FIG.

Incidentally, FIG. 3 shows characteristic curves of the output current and input torque with respect to the generator rotational speed in the cold and hot parts of the alternating current generator 1 of this embodiment.

When the voltage of the battery 10 is low and its remaining capacity is low, the transistor 15 is turned on in the voltage regulator 14, and current flows through the field winding 3, causing the output voltage of the generator 1 to reduce the battery 10.
is charged. At this time, the output voltage from the voltage regulator 14 is controlled by the transistor 28, and in the hot part where the temperature of the generator 1 has become high after time has elapsed since the start of power generation, the output voltage from the voltage regulator 14 is controlled by the comparator 23. Since the transistor 28 is kept in the OFF state, the original field current control by the voltage regulator 14 is carried out.Therefore, the characteristic curve of the input torque and the output current becomes as shown by the broken line in FIG.

Further, when the temperature of the generator 1 is low immediately after starting power generation, the conductivity of the transistor 28 is controlled by the comparator 23, so that the lower the temperature, the more the field current is limited. Furthermore, when the rotational speed of the generator 1 exceeds N1 during this cold period, the comparator 30 cuts off the output of the comparator 28 and keeps the transistor 28 in an off state.

The original field current control is performed by the voltage regulator 14 in the same manner as in the above-mentioned heating section.

Therefore, when the rotational speed of the generator 1 is N1 or less in cold conditions, the field current is limited, so the characteristic curves of input torque and output current in cold conditions, which are normally higher than in hot parts, are shown as solid lines in Figure 3. As shown, it is limited to the same value as the hot part. or,
When the rotational speed of the generator 1 exceeds N1 in cold conditions, the field current is no longer limited, and the characteristic curves of input torque and output current shift to the characteristic curves in cold conditions.

On the other hand, when the voltage of the battery 10 is high and the remaining capacity is large, the voltage regulator 14 maintains the transistor 15 in the off state regardless of whether the transistor 28 is on or off.

Therefore, current no longer flows through the field winding 3 and the battery 10
Charging will be stopped.

In this way, the control device for the vehicle alternator of this embodiment has the following features:
Since the input torque in the cold state is reduced to the same level as that in the hot section when the generator rotation speed is N1 or less, the peak of the input torque that occurs in this rotation range can be reduced. Therefore, when the alternating current generator 1 is driven by the internal combustion engine for driving the vehicle as in this embodiment, it is difficult to stabilize the rotation even when the internal combustion engine is cold and has not finished warming up. At the same time, fuel consumption can be reduced.

Further, for example, when the generator 1 is driven by a hydraulic pump, the input torque is reduced to the same extent as in the hot part even when the generator is cold, so that the generator 1 can be sufficiently driven by a small hydraulic pump.

Furthermore, the control device for the vehicle alternator of this embodiment does not control the field current based on the heat generation temperature when the rotational speed of the generator 1 exceeds N1. In comparison, the output current can be increased. Therefore, when operating a load that is frequently used in cold weather and consumes a large amount of power, such as a metal thin film heater that melts ice or frost on a vehicle's windshield, the internal combustion engine may be idled up. By simply increasing the number of rotations of the generator to exceed N1, the output current increases and the load can be easily operated. Also, if you do this, the input torque in the region where the generator rotation speed exceeds N1 will be higher than the hot part, but as mentioned above, the peak of the input torque is in the rotation region below N1, so it will be applied to the drive source. The maximum load will not increase. Therefore, problems such as uneven rotation of the internal combustion engine due to the increase in load described above can be avoided.

Note that the present invention is not limited to the above-mentioned embodiment. For example, in the above-mentioned embodiment, when the generator rotation speed exceeds N1, the field current based on the temperature of the stator winding 2 is reduced even when the generator is cold. However, this operation may be performed in response to the operation of a heater switch provided in the driver's seat instead of being performed in accordance with the rotational speed of the generator. In other words, with this configuration, by limiting the field current when the heater switch is not turned on and the heater, which consumes a large amount of power, is not operating, the input torque and output current in the cold state can be kept at the same level as in the hot part. When the heater is used in cold weather, the output current is increased when the heater switch is turned on to cover the power consumed by the heater.

Further, in the above embodiment, the smoothing circuit 26 was provided to detect the field current flowing through the field winding 3, but instead of this smoothing circuit 26, a shunt resistor was used to directly detect the field current. You can.

[Effects of the Invention] As detailed above, the vehicular alternator of the present invention has Ill
#The device exhibits excellent effects such as reducing the input torque as appropriate to reduce the load applied to the drive source, and preventing a drop in output current to operate a load with large power consumption.

[Brief explanation of drawings]

Fig. 1 is an electric circuit diagram showing the electrical configuration of the control device of the embodiment, Fig. 2 is an electric circuit diagram showing details of the field current control circuit, and Fig. 3 is the generator rotation of the ili control device of the embodiment. FIG. 4 is a diagram showing a characteristic curve of input torque and output current with respect to the generator rotation speed of a conventional control device. 1 is an alternating current generator; 13 is a thermistor as a temperature detection means; 14 is a voltage regulator that constitutes a voltage adjustment means; 15 is a transistor that constitutes a voltage adjustment means; 16, 17.1
9 to 22.27 is a resistance constituting the field current 11 means, 1
Reference numeral 8 denotes an amplifier constituting the field current adjusting means; 23 a comparator constituting the field current adjusting means; 26 a smoothing circuit constituting the field current adjusting means; 28 a transistor constituting the field current adjusting means; 29 is F/V as rotation speed detection means
a converter, and 30 a comparator as an invalidating means.

Claims (1)

[Scope of Claims] 1. An alternating current generator mounted on a vehicle; voltage adjusting means for controlling the field current of the alternating current generator based on the battery voltage of the vehicle and adjusting its output voltage; and the alternating current generator. temperature detection means for detecting the temperature of the generator; and when the temperature detected by the temperature detection means is low, the field current of the alternator controlled by the voltage adjustment means is controlled based on the temperature; A control device for a vehicular alternating current generator comprising a field current adjusting means, comprising a disabling means for appropriately disabling control of the field current by the field current adjusting means. Generator control device.