JPS59220030A - Ac generating device for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alternating current generator for vehicles such as automobiles, which reliably controls charging without causing battery constant temperature to become overvoltage.

The alternating current generator used for a car is driven to rotate by the vehicle engine, and its rotational speed varies significantly depending on the operating state of the engine. Therefore, the output voltage of this type of generator has elements that vary widely, and means for controlling the generator output voltage is required. As this output voltage control means, a voltage regulator is usually used which detects the entire generator output voltage and controls the excitation current of the field excitation winding of the generator. sand'
That is, the excitation winding current is controlled to increase or decrease so that the generator output voltage becomes a predetermined voltage.

However, if, for example, the output terminals of the generator become disconnected, a transient surge voltage will occur in the generator output. Regardless of the rotational speed of the generator, its excitation current can be in a fully excited state, and the surge voltage of the generator increases linearly in proportion to the rotational speed. Therefore, the withstand voltage of the voltage regulator and electrical load must be set to be higher than the maximum surge voltage at the maximum allowable rotational speed of the generator.

This invention was made in view of the above points, and even if the rotation speed of the generator increases, it effectively prevents a transient surge voltage from rising and improves the voltage safety of electrical loads, etc. It is an object of the present invention to provide a vehicle alternating current generator that can be peeled off.

That is, the AC photoelectric device @ according to the present invention is configured so that the excitation current flowing through the field excitation winding of the generator is controlled by a control element, and this control element controls the voltage for detecting the generator output voltage, etc. Control is performed by a detection control circuit and an excitation current control circuit that completely reduces the excitation current when the generator rotational speed exceeds a set rotational speed.

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows its configuration. 1 is an alternating current generator, which is equipped with a three-phase output winding 12 wound around a stator and a field excitation winding 13 wound around a rotor. , Output winding 1
The alternating current voltage generated at 2 is rectified by a rectifier circuit 14 and taken out from output terminals a and b. A vehicle battery power source 15 is connected between the output terminals a and 5, and one negative terminal thereof is grounded. The excitation winding 13 is supplied with an excitation current from the battery power supply 15 via the transistor I6, which serves as an excitation current intermittent control element, and the excitation winding 13 is connected in parallel to the flywheel. A diode 17 is connected.

For the pace of the excitation current control transistor 16, the voltage detection control circuit 18 and the excitation current control circuit 1
A control signal from 9 is supplied. Voltage detection control circuit 18
is driven in response to the turning on of the key switch 20, detects the charging terminal voltage of the battery power source 15, and applies an excitation current to the excitation winding 13 so that the generated output voltage of the generator 1 becomes a predetermined voltage. Control.

The excitation current control circuit 19 also includes a frequency-voltage conversion circuit 2 and a reference triangular wave generation circuit 22, which are driven when the key switch 20 is turned on. Frequency-voltage conversion circuit 2
1 detects an AC power generation voltage signal from the output winding 12 of the generator 11 and generates a voltage signal corresponding to the frequency of this AC voltage signal. That is, the frequency of this AC voltage signal corresponds to the rotational speed of the generator 11, and therefore, the frequency-voltage conversion circuit 21 obtains a voltage signal corresponding to the generator rotational speed. Reference triangular wave generation circuit 22
In this case, a triangular wave voltage signal having a specific period and a specified level is generated, and this triangular wave voltage signal is compared in a comparison circuit 23 with a voltage signal corresponding to the generator rotation speed. The output signal of the comparator circuit 23 controls a transistor 24, and the transistor 24 controls the base of the excitation current control transistor 16.

That is, when the key switch 2θ is turned on and the alternating current generator 11 is rotationally driven by the engine, an alternating current voltage is generated from the output winding 12, rectified by the rectifying circuit 14, and charged into the battery power source 15. In normal operating conditions, the voltage detection control circuit 18 detects the charging voltage for the battery power source 15, controls the transistor 16, and controls the excitation current for the excitation winding 13 to obtain a power generation output of a predetermined voltage. I'm trying to be able to do that.

Further, in response to the power generation operation as described above, the frequency-voltage conversion circuit 21 generates a voltage signal depending on the rotation speed of the generator 1 as shown in FIG. This converted voltage signal is then supplied to the positive input terminal of the comparator circuit 23. A triangular wave voltage signal as shown in FIG. 3 from the reference triangular wave generating circuit 22 is input to the negative input terminal of the comparator circuit 23. Although determined by the characteristics, it is about several ms to several tens of m8. Further, the lowest potential vb of the triangular wave is made to match the output voltage of the frequency-voltage conversion circuit 2 when the rotation speed Nb generates the allowable surge voltage VBMAX of the alternator 11. However, this surge voltage VB
1 for the rotational speed Nb of the alternator 11 that generates MAX,
Converted to the number of revolutions of the vehicle ennon, 4000 to 5000
It is desirable to avoid setting the speed to be less than the rpm, as this may actually cause a deterioration in the charging balance of the battery power source 15.

Therefore, when the rotation speed of the generator 1 exceeds Nb, the frequency-voltage conversion circuit 21
The output voltage ■o becomes higher than Vb by υ, and the output signal from the comparator 23 becomes a rectangular waveform as shown in (B) of the figure.

Then, this signal controls the transistor 24, and the excitation current control transistor 16f is controlled with a waveform as shown in (Q) in the same figure, so that the excitation current to the excitation winding 13 is intermittent.

That is, as shown in Fig. 5, the rotation speed of the generator 1) is N.
When the rotation speed exceeds bk, the excitation current A to the excitation winding 13 is reduced in accordance with the rotation speed, and the surge voltage B is also controlled to be equal to or less than the allowable surge voltage VBMAX.

As described above, according to the present invention, when an alternator for a vehicle reaches a certain rotational speed (for example, 4000 to 5000 rpm converted to engine rotational speed), which occurs infrequently in actual use, the rotational speed The current is controlled to be reduced intermittently, and the surge voltage of the generator can be effectively lowered. Therefore, the allowable withstand voltage of the output load circuit of this generator can be set low, and this has great effects in reducing costs and improving reliability.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram illustrating the entire alternating current generator device according to an embodiment of the present invention, Fig. 2 is a diagram showing the relationship between the generator rotation speed and converted voltage in the above embodiment, and Fig. 3 is a comparison diagram. FIG. 4 is a diagram similarly explaining the signal comparison state and excitation current control state, and FIG. 5 is a diagram showing the relationship between the excitation current and surge voltage of the generator device. 1. AC generator, 12. Output winding, 13.
... Excitation winding, 16... Transistor (for exciting current control), 18... Voltage detection control circuit, 19... Excitation current control circuit.

Claims (1)

[Claims] an alternating current generator including an output winding and a field excitation field line; a control element that controls an excitation current supplied to the excitation winding of the generator; a voltage detection control circuit for detecting at least one of the battery power supply voltages and controlling the control element; a means for detecting the total number of rotations of the generator; An alternating current generator for a vehicle, characterized in that it is completely equipped with an excitation current control circuit that controls the above-mentioned control element and reduces excitation current.