JPH0217899A - Ac generator for vehicle - Google Patents

Abstract

PURPOSE:To reduce the number of switching contacts by providing a switching means to short across connecting lines which connect a plurality of full wave rectifiers respectively to rectify AC outputs of each stator coil in full wave. CONSTITUTION:In the low speed region of a vehicle engine a switching means 6 is closed to short between connecting lines 5a to 5c. Under this condition, each stator coil 1A and 1B is connected in series each other to an electric load 3 through full wave rectifiers 2A and 2B, so that output current can be obtained even in the low speed region of the vehicle engine. In the high speed region of the vehicle engine, the switching means 6 is caused to be opened and each connecting line 5a to 5c is separated. Under this condition, each stator coil 1A and 1B is connected in parallel each other to the electric load 3 through the full wave rectifiers 2A and 2B, where the resistance loss in the high speed rotation of the engine is so reduced that sufficient output power can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an alternator for a vehicle, and more particularly to an alternator that can obtain a sufficient output current from a low rotation range to a high rotation range of a vehicle engine.

[Prior Art] Such an alternator generates power in a stator coil using a rotating magnetic field of a rotor coil rotated by a vehicle engine, and the greater the number of windings of the stator coil, the greater the output in a lower rotation range of the engine. However, if the coil volume is kept the same, the wire diameter will become thinner as the number of turns increases, resulting in increased resistance loss in the high engine speed range and suppressed output current.

Therefore, for example, in Japanese Patent Application Laid-Open No. 58-95999, each phase coil of the rotor coil is divided into two, and in the low engine speed range, the divided coils are connected in series to increase the number of turns, thereby lowering the rotor coil. An alternating current generator has been proposed in which output is obtained at a rotational speed, and sufficient output current is obtained by connecting the divided coils in parallel in a high rotational range to reduce resistance loss.

[Problems to be Solved by the Invention] The above-mentioned conventional alternating current generator achieves the intended purpose by switching the divided coils in series and parallel, but the arrangement of the divided coils is relatively complicated and A problem is that parallel switching requires a relatively large number of switch contacts.

The present invention solves these problems, and aims to provide a vehicle alternator that can simplify the structure of the stator coil, reduce the number of switch contacts, and improve its reliability. .

[Means for Solving the Problems] To explain the configuration of the present invention with reference to FIG. 1, an alternating current generator connected to a vehicle engine and rotating is provided with a plurality of three-phase stator coils IA and IB connected in the same way, Each phase coil lla, 1 corresponding to each other of these stator coils IA, IB
2a, llb, 12b, llc, and 12c are set to generate a common mode voltage.

Further, a plurality of full-wave rectifiers 2A and 2B are provided for full-wave rectifying the alternating current outputs of the stator coils IA and IB, respectively, and the positive side diode 21a of one full-wave rectifier 2A is
, 21b, 21c cathodes and another full-wave rectifier 2
The anodes of the negative side diodes 22d, 22e, and 22f of B are connected to the on-vehicle electrical load 3, respectively, and the anodes of the negative side diodes 21d, 21e, and 21f of each phase of the two full-wave rectifiers 2A and the remaining full-wave rectifiers are connected to The other full-wave rectifier 2B and the cathodes of the positive-pole side diodes 22a, 22b, and 22C of each phase of the full-wave rectifiers are connected by connection lines 5a, 5b, and 5c, respectively.

A switch means 6 is provided between each of the connection lines 5a to 5C to short-circuit them, and the switch means 6 is operated to close in the low speed range of the vehicle engine, and the switch means 6 is closed in the high speed range of the vehicle engine. A switching control means 7 for operating the opening is provided.

[Operation] When the switch means is closed in a low rotational speed range of the vehicle engine, the connection lines are short-circuited.

In this state, the stator coils are connected in series to the on-vehicle electrical load via a full-wave rectifier, and an output current can be obtained even at low engine speeds.

In a high speed range of the vehicle engine, the switch means is opened. The connection lines are separated, and in this state, the stator coils are connected in parallel to the on-vehicle electrical load via a full-wave rectifier. This reduces resistance loss at high engine speeds and provides sufficient output current.

In the present invention, since it is sufficient to provide the switch means for short-circuiting between the three-phase connection lines, the number of switch contacts can be reduced and reliability can be improved.

Furthermore, since the stator coils need only be provided with the same wire connections, the arrangement of the coils is simplified.

[First embodiment] In FIG. 1, the alternator has a pair of stator coils I
A, IB, these stator coils IA, IB are connected to the same star connection, and each phase coil lla corresponds to
, 12a, llb, 12b, 11c, and 12c so that a common mode voltage is generated.

Each of the stator coils IA and IB is connected to a three-phase full-wave rectifier 2A and 2B, respectively, and each full-wave rectifier 2A and 2B is connected to three positive-side diodes 21a, 21b, 21c and 22a, 22b, 22C and a negative-side diode. diode 21d
, 21e, 21f and 22d, 22e, 22f.

and each phase coil 11a of the stator coil IA,
llb and llc are the positive side diodes 21a, 21b, 21c and the negative side diode 21d connected in series.
, 21e, 21f, and the positive side diodes 22a, 22b, 2 connected in series with each phase coil 12a, 12b, 12c of the stator coil IB.
2c and the negative side diodes 22d, 22e, and 22f.

The cathodes of the positive side diodes 21a, 21b, and 21c are connected to each other and reach the positive side of the vehicle battery 4 and the vehicle electric load 3 connected in parallel thereto, and
The anodes of the negative side diodes 22d, 22e, and 22f are grounded.

The anodes of the negative diodes 21d, 21e, and 21f and the cathodes of the positive diodes 22a, 22b, and 22c are connected to each other by connecting wires 5a, 5b, and 5c, respectively, and between these connecting wires 5a, 5b, and 50, A switch circuit 6 is provided with normally closed contacts 61 and 62. The coil 63 of the switch circuit 6 is energized by the C terminal output of the switching control circuit 7, and the above-mentioned contacts 61.6
2 is activated to open.

As is well known, the stator coils IA and IB generate power as follows:
This is generated by the rotating magnetic field of the rotor coil of the same rating rotated by the vehicle engine, and the excitation of this rotor coil is controlled ON-OFF by the regulator of the same rating, so that the DC voltage applied to the battery 4 and the electric load 3 always maintains a predetermined value. The stator coil power generation amount is controlled as shown.

The output of the phase coil llc of the stator coil IA is input to the b terminal of the switching control circuit 7, and this output exhibits a frequency proportional to the generator rotational speed N. Moreover, the operating power is supplied from the battery 4 to the a terminal of the switching control circuit 7, and the d terminal is grounded.

Details of the switching control circuit 7 are shown in FIG.

The control circuit 7 is composed of an F/V converter 71, a Zener diode 72, a transistor 73, etc.
The V converter 71 generates a voltage output proportional to the frequency of the output of the phase coil 11C (ie, the generator rotational speed N). When this voltage output exceeds the Zener voltage, the transistor 73 becomes conductive and the relay coil 63 is energized and excited. The Zener voltage in this case is set so as to cause the transistor 73 to conduct when the generator rotational speed N exceeds No, which will be described later.

In an alternator with such a configuration, the generator rotation speed N is N
Below o, the coil 63 of the switch circuit 6 is in a de-energized state, the contacts 61 and 62 remain closed and the connecting wires 5a and 5
b, 50 are short-circuited.

In this state, each of the stator coils IA, I
B are connected in series to the electrical load 3 via full-wave rectifiers 2A and 2B.

This will be explained with reference to FIG. The figure shows each stator coil IA,
This shows a state where the maximum voltage is generated between the IB phase coils lla, llb and 12a, 12b. In this state, the diodes 21a, 21e, 22a,
Only 22e is conductive, and the others are reverse biased and non-conductive.

Therefore, the output current to the electrical load is transmitted through the diode 22e.
, phase coils 12b, 12a, diode 22a, contact 6
1, the flow passes through the diode 21e, the phase coils 11b, lla, and the diode 21a, and the phase coils lla, llb, 1
2a and 12b are in series.

Therefore, the output current characteristics of the alternating current generator exhibit the characteristics when the coils are connected in series (line X in FIG. 5) below the rotational speed No.

When the generator rotational speed N becomes equal to or higher than No, the coil 63 of the switch circuit 6 is excited and the contacts 61 and 62 are opened. In this state, phase coils lla, 11b and 12a, similar to the above,
When the maximum voltage occurs across 12b, as shown in Figure 4,
In this case, diodes 21a, 21d, 21e, 22
a, 22b, 22e conduct, and the output current to the electrical load is transmitted through the diodes 22e, 22b, 21e, and the phase coil 11.
b, lla, a circuit passing through diode 21a, diode 22e, phase coils 12b, 12a, diode 22a
, 21d, 21a, the phase coil lla,
llb, 12a, and 12b are in a parallel state.

Therefore, the output current characteristic of the alternator exhibits the characteristic when the coils are connected in parallel (line y in Fig. 5) at the rotational speed No. or higher.

In the end, the output current characteristics of the alternator in this example are as follows:
If the rotational speed NO is set at the intersection of both characteristic curves, it will be as shown by the thick solid line, and a sufficient current can be output from the low to high generator rotational speed ranges.

[Second Embodiment] FIG. 6 shows a second embodiment of the present invention, in which connecting wires 5a, 5
The contacts of switch circuit 'd@6 which short-circuit between b and 50 are triac 64.65, and these triac 64
．． 65 is provided with a pulse transformer 66 for generating a trigger pulse. Switching control circuit 7
'' emits a pulse when the rotational speed of the generator is below a predetermined rotational speed, and makes the triacs 64 and 65 conductive.Other configurations are the same as in the first embodiment.

This configuration not only provides the same effect, but also improves reliability further by making the switch non-contact.

[Third Embodiment] The number of installed stator coils is not limited to two as in each of the above embodiments, but can be increased to three by adding stator coil ICs as shown in FIG. A new full-wave rectifier 2C for the coil IC will be installed. in this case,
Connection wires 5a, 5 connecting full wave rectifiers 2A, 2B, 2C
Switch circuits 6A and 6B are provided between b, 5C and 5d, 5e, and 5f, respectively, and are operated by the C terminal output of the switching control circuit 7.

According to such a configuration, even better performance can be obtained.

In the first embodiment, series-parallel switching was performed at the rotational speed NO at which the output currents intersect, but it can also be performed at the rotational speed N1 at which the engine load torque intersects, which reduces the shock to the engine at the time of switching. becomes smaller.

This is shown in FIG. In the figure, the line S is the torque curve when the coils are connected in series, and the line t is the torque curve when the coils are in parallel.Switching between series and parallel is performed at the rotation speed N1 where these curves intersect.

In this case, the output current changes discontinuously as shown by the thick solid line, but the same effect as in each of the above embodiments is achieved.

In each of the above embodiments, the stator coils are star-connected, but they may be delta-connected.

[Effects of the Invention] As described above, according to the alternating current generator of the present invention, it is possible to significantly reduce the number of series-parallel switching switches installed for a plurality of stator coils, thereby improving reliability. The arrangement of the stator coils can also be simplified.

[Brief explanation of the drawing]

1 to 5 show a first embodiment of the present invention.
The figure is the overall circuit diagram of the alternator, Figure 2 is the circuit diagram of the switching control circuit, Figures 3 and 4 are the main circuit diagrams showing the operating status of the high current generator, and Figure 5 is the alternator. The output current characteristic diagrams of FIG. 6 and FIG.
and an overall circuit diagram of an alternator showing the third embodiment, No. 8
The figure is an output current characteristic diagram of an alternator in another example of the present invention. 1A, IB, IC... stator coil 11a, llb
, llc, 12d, 12e, 12f... Phase coils 2A, 2B, 2C... Full-wave rectifier 3... Vehicle-mounted electrical load 4... Vehicle-mounted battery 5a, 5b, 5c, 5d, 5e, 5f...・Connection line 6.
6A, 6B...Switch circuit (switch means) 7.7
゛...Switching control circuit (switching control means) Fig. 1 Fig. 3 Fig. 2, 77 Fig. 5 N. Generator rotation speed (N) Figure 4 Figure 6 Figure 7

Claims (1)

[Claims] A plurality of three-phase stator pools with the same wiring are provided in an alternating current generator that is connected to a vehicle engine and rotates, and the mutually corresponding phase coils of these stator coils are set to generate an in-phase voltage. A plurality of full-wave rectifiers are provided to perform full-wave rectification of each AC output, and the cathode of the positive diode of one full-wave rectifier and the anode of the negative diode of the other full-wave rectifier are respectively connected to the on-vehicle electrical load. In addition, the anode of the negative diode of each phase of the one full-wave rectifier and the remaining full-wave rectifier, and the cathode of the positive diode of each phase of the other full-wave rectifier and the remaining full-wave rectifier, respectively. connected by a connecting line, and providing a switch means between each of the connecting lines to close and short-circuit them, and operating the switch means to close and short-circuit the connecting lines in a low rotation range of the vehicle engine,
An alternator for a vehicle, characterized in that it is provided with switching control means for opening and operating the switch means in a high rotation range.