JPH0648400U - Control device for vehicle alternator - Google Patents

Abstract

(57) [Summary] [Purpose] When the electric load 9 of the vehicle is turned on, the AC generator 1
Output current is gradually changed to prevent the driving torque of the AC generator 1 from rapidly increasing, thereby preventing the engine speed from being lowered and causing the vehicle operator to feel uncomfortable and discharging the storage battery 7. The purpose is to suppress as much as possible. [Structure] AC generator 1 when the electric load 9 of the vehicle is turned on, etc.
There is provided a means for increasing the conductivity of the output transistor 308 by a predetermined amount and then gradually increasing it when the output voltage of the output voltage becomes lower than a predetermined value.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a control device for a vehicle AC generator.

[0002]

[Prior art]

 FIG. 4 is a circuit diagram showing a conventional apparatus. In the figure, reference numeral 1 is an AC generator driven by an engine (not shown) mounted on a vehicle, and having an armature coil 101 and a field coil 102. There is. Reference numeral 2 is a rectifier for full-wave rectifying the AC output of the AC generator 1, and has output terminals 201, 202 and 203. 201 is a main rectification output terminal, 202 is an auxiliary rectification output terminal for flowing an exciting current of the field coil 102, 203 is a grounding terminal, 3 is an exciting current of the field coil 102 by detecting a generated voltage of the generator. Is a voltage regulator that intermittently controls the generator and controls the voltage generated by the generator to a predetermined value, and is composed of the following parts. 301 302 is a voltage dividing resistor that divides the voltage generated by the generator, 303 and 304 are voltage dividing resistors that divide the voltage of the constant voltage source (A) to form the reference voltage, and 305 is a generator that is divided by 301,302. It is a comparator that compares the voltage with the reference voltage divided by 303 and 304, and detects the voltage generated by the generator.

Reference numeral 306 is a transistor which is intermittently connected according to the output of the comparator 305, 307 is a base resistance of the transistor 306, and 308 is an output transistor which is intermittently controlled by the transistor 306 to control the field current of the field coil 102. Control. Reference numeral 309 is a base resistance of the output transistor 308, and 310 is a diode which is connected in parallel to the field coil 102 and absorbs the intermittent surge generated in the field coil 102. 7 is a storage battery mounted on the vehicle and charged by the rectified output of the generator 1, 8 is a key switch, 9 is an electric load of the vehicle, 10 is an electric load switch, 11 is a backflow prevention diode, and 12 is a field coil 102. This is the resistance for the initial excitation of.

Next, the operation will be described. When the key switch 8 is closed at the time of starting the engine, the output transistor 308 is connected to the base from the storage battery 7 via the key switch 8, the backflow prevention diode 11, the initial excitation resistor 12, and the base resistor 309 of the output transistor 308. A current flows and the output transistor 308 becomes conductive. When the output transistor 308 conducts, a field current flows from the storage battery 7 to the field coil 102 through the key switch 8, the backflow prevention diode 11, the initial excitation resistor 12, the field coil 102, and the output transistor 308. The generator 1 is in a state capable of generating power.

Next, when the engine is started and the generator 1 is rotationally driven to start power generation, the voltage regulator 3 compares the generated voltage of the generator 1 with a reference voltage composed of a voltage dividing resistor 301 302 and a voltage dividing resistor 303 304. The voltage generated by the generator 1 is divided by the voltage dividing resistor 301 302, and the voltage of the constant voltage source (A) exceeds the predetermined value set by the voltage dividing resistor 303 304. The comparator 305 is changed from the conductive state to the cutoff state, and the transistor 306 which is interrupted according to the output of the comparator 305 is conductive. On the contrary, when the voltage generated by the generator 1 is divided by the voltage dividing resistor 301 302 and becomes equal to or lower than the predetermined value set by the voltage dividing resistor 303 304, the comparator 305 changes from the cutoff state to the conduction state and the transistor 306 changes from the conduction state. It will be cut off. The output transistor 308 is turned on and off by the above-mentioned turning on and off of the transistor 306, and the field current flowing through the field coil 102 is turned on and off to adjust the voltage generated by the generator 1 to a predetermined value.

[0006]

[Problems to be solved by the device]

 By the way, in such a conventional device, when the electric load 9 of the vehicle is in a light load state and the relatively large electric load 9 of the vehicle is conducted by the switch 10 and the output current of the generator 1 suddenly increases, Since the driving torque of the generator 1 is increased, there is a problem that the engine speed that drives the generator 1 is lowered or the driver of the vehicle is uncomfortable.

The present invention has been made to solve the above problems, and when the electric load of the vehicle is turned on, the output current of the generator is gradually changed so that the drive torque of the generator is changed. It is an object of the present invention to provide a control device for an AC generator that can prevent the engine speed from dropping and the driver's uncomfortable feeling by preventing a sudden increase, and can suppress the discharge of the storage battery as much as possible.

[0008]

[Means for Solving the Problems]

 A detection circuit that detects the output voltage of a vehicle AC generator that has a field coil and outputs a signal voltage, a smoothing circuit that smoothes the signal voltage and outputs a smoothed voltage, and a triangular wave voltage at a fixed frequency. Generating a pulse-width modulated wave whose pulse width gradually changes by comparing the triangular-wave voltage with the smoothed voltage from the smoothing circuit, and a comparator based on the pulse-width modulated wave. When the output voltage of the AC generator falls below a specified value and the conductivity of the semiconductor switching device is increased by a specified amount when the output voltage of the AC generator falls below a specified value, the semiconductor switching device is gradually increased. And means for raising.

[0009]

[Action]

 Since the smoothing circuit in this invention delays the followability of the operation of the detection circuit, the semiconductor switching element does not perform the intermittent operation of the detection circuit even when the electric load of the vehicle is applied, and the smoothing circuit The intermittent operation of the comparator that compares the voltage with the triangular wave voltage is performed up to the operation level of the detection circuit. Further, when the electric load of the vehicle is turned on and the output voltage of the AC generator becomes equal to or lower than a predetermined value, the conductivity of the semiconductor switching device is increased by a predetermined value and then gradually increased.

[0010]

【Example】

 Example 1. An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, 318 is a backflow prevention diode that blocks current when the comparator 305 is cut off, 319 is a level shift diode connected in series to the base terminal of the transistor 306,

Reference numeral 4 compares the generated voltage of the generator 1 with the detection voltage set by the voltage dividing resistors 301, 302 and the voltage of the constant voltage source (A) with a predetermined value set by the voltage dividing resistors 303, 304. It is a circuit that smoothes the output of the comparator 305, which is a detection circuit that emits a binary signal voltage, and is configured by the following parts.

[0012] 401 is a backflow prevention diode that blocks current when the comparator 305 is cut off, 402 is a resistor that defines a time constant when the capacitor 404 is charged when the comparator 305 is cut off, and 403 is the resistance A diode that charges and holds a capacitor 404 described later via 402, 404 is a capacitor that is charged when the comparator 305 is cut off, and 405 is a time constant when the capacitor 404 is discharged when the comparator 305 is conductive. Resistance to

Reference numeral 5 denotes a triangular wave generator that generates a triangular wave voltage at a constant cycle in a predetermined voltage region, and 6 compares the smoothed voltage by the smoothing circuit 4 with the triangular wave voltage of the triangular wave generator 5. This is a comparison circuit for intermittently controlling the output transistor 308, and is composed of the following parts. Reference numeral 601 is a comparator for comparing the smoothed voltage by the smoothing circuit 4 with the triangular wave voltage of the triangular wave generator 5, and 602 is a transistor which is a controller for intermittently controlling the output transistor 308 according to the output of the comparator 601. Reference numeral 603 is a base resistance of the transistor 602.

Next, the operation will be described. When the generated voltage of the generator 1 is adjusted to a predetermined value with a constant electric load of the vehicle, the pulse output from the comparator 601 that compares the smoothed voltage of the smoothing circuit 4 with the triangular wave voltage of the triangular wave generator 5 The width-modulated wave becomes a duty ratio of blocking and conducting the field current necessary for the output current of the generator 1, and the transistor 602 controls the output transistor 308 according to the output of the comparator 601 to output the output transistor 308. Controls the field current flowing through the field coil 102 intermittently to adjust the voltage generated by the generator 1 to a predetermined value.

Next, when the electric load 9 of the vehicle is turned on by the switch 10 (shown in FIG. 3A), the voltage generated by the generator 1 is divided by the voltage dividing resistor 301 302 to obtain the constant voltage source (A). The voltage becomes less than the specified value set by the voltage dividing resistors 303 and 304, the comparator 305 changes from the cut-off state to the conduction state (shown in FIG. 3b), the transistor 306 changes from the conduction state to the cut-off state, and the output transistor 308 outputs 100% duty ratio. Although it tries to pass the field current to the field coil 102 by conducting at the (conduction rate), the voltage smoothed by the smoothing circuit 4 is transferred from the capacitor 404 to the resistor 405 because the comparator 305 is in the conducting state. It becomes the discharge voltage.

Here, if the ratio of the resistance values of the resistor 402 and the resistor 405 is set to 2: 1, the capacitor 404 is charged with this voltage division ratio. For example, before the electric load 9 is turned on, the output transistor 308 becomes 50 When the duty ratio (conductivity) is controlled by the transistor 306, the capacitor 404 is charged at a duty ratio of 66.7%, so that the duty ratio of the output transistor 308 is 50%. have priority .

On the other hand, when the electric load 9 is turned on, the transistor 306 is cut off and the duty ratio of the output transistor 308 is controlled to be 100%, so that the duty ratio of the output transistor 308 charged in the capacitor 404 is controlled. The transistor 602 is controlled with a duty ratio of 66.7%, and the control of the transistor 602 is prioritized. Therefore, the duty of the output transistor 308 can be increased from the duty ratio of 50% to the duty ratio of 66.7%.

The discharge time constant composed of the capacitor 404 and the resistor 405 is large (shown in FIG. 3C), and the output of the comparator 601 is compared with the discharge voltage of the triangular wave generator 5 and the smoothing circuit 4, and the generated voltage of the generator 1 is The transistor 602 is turned on and off according to the output of the comparator 601 by performing the turning on / off operation at a constant cycle until the predetermined value is reached, and the output transistor 308 is turned on and off as shown by e in FIG. The field current flowing through the field coil 102 is controlled by the intermittent duty cycle, and the generation of the output current of the generator 1 is delayed as shown in FIG. 3f.

When the output current of the generator 1 reaches a current corresponding to the electric load 9 of the vehicle conducted by the switch 10 and the generated voltage of the generator 1 reaches a predetermined value, the output of the comparator 601 is The duty ratio of conduction and interruption of the field current required for the output current of the machine 1 is set, and the transistor 602 is intermittent according to the output of the comparator 601 to control the output transistor 308 to control the field current flowing in the field coil 102. It controls and adjusts the generated voltage of the generator 1 to a predetermined value.

As described above, even if the electric load 9 of the vehicle is turned on by the switch 10, the output transistor 308 is controlled by comparing the discharge voltage of the voltage by the smoothing circuit 4 and the triangular wave voltage of the triangular wave generator 5. As a result, as shown in FIG. 2, the output current of the generator 1 can be suppressed for a certain period of time, and a sudden increase in drive torque can be prevented.

When the electric load 9 of the vehicle is turned on by the switch 10, the conductivity of the output transistor 308 is raised by a predetermined amount, and then the conductivity is gradually increased. Therefore, the conductivity of the output transistor 308 is increased. It is possible to suppress the discharge of the storage battery 7 as much as possible by reducing the time during which the charge gradually rises.

Example 2. Although the comparator 305 is used to detect the voltage generated by the generator 1 in the above embodiment, a detection circuit including a transistor and a zener diode may be used.

[0023]

[Effect of device]

 As described above, according to this invention, a detection circuit that detects the output voltage of a vehicle AC generator having a field coil and outputs a signal voltage, and a smoothing circuit that smoothes the signal voltage and outputs a smoothed voltage. A circuit, a triangular wave oscillator that generates a triangular wave voltage at a constant period, a comparator that compares the triangular wave voltage and the smoothed voltage from the smoothing circuit, and outputs a pulse width modulated wave whose pulse width changes gradually, A semiconductor switching element for intermittently controlling the field current supplied to the field coil based on the pulse width modulated wave, and the semiconductor open circuit by the pulse width modulated wave when the output voltage of the AC generator falls below a predetermined value. By providing a means for gradually increasing the conductivity of the closed element after increasing it by a predetermined amount, the output generated when the electric load is applied can be suppressed for a certain period of time, so that the driving torque when the electric load is applied is suppressed. It can, drop in the rotational speed of the engine of a vehicle, also it is possible to prevent discomfort to the vehicle operator, moreover, has the advantage of being able to suppress the discharge of the battery as much as possible.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment according to the present invention.

FIG. 2 is a characteristic diagram showing a comparison between one embodiment of the present invention shown in FIG. 1 and a conventional example.

FIG. 3 is a characteristic diagram of each part according to an embodiment of the present invention.

FIG. 4 is an electric circuit diagram of a conventional device.

[Explanation of symbols]

 1 AC generator 2 Rectifier 3 Voltage regulator 4 Smoothing circuit 5 Triangular wave generator 6 Comparison circuit 7 Storage battery 9 Electric load 101 Armature coil 102 Field coil 308 Output transistor 402,405 Resistance 404 Capacitor 601 Comparator 602 Transistor

Claims (1)

[Scope of utility model registration request] 1. A detection circuit for detecting an output voltage of a vehicle alternator having a field coil to generate a signal voltage, a smoothing circuit for smoothing the signal voltage and outputting a smoothed voltage, and a triangular wave pattern at a constant cycle. A triangular wave oscillator that generates a voltage, a comparator that compares the triangular wave voltage and the smoothed voltage from the smoothing circuit, and outputs a pulse width modulated wave whose pulse width changes gradually, and the field magnet based on the pulse width modulated wave. A semiconductor switching device for intermittently controlling the field current supplied to the coil, and when the output voltage of the alternator falls below a predetermined value, the pulse width modulated wave increases the conductivity of the semiconductor switching device by a predetermined amount. After that, a control device for the vehicle alternator, which is provided with a means for gradually raising the temperature.