JP2003134767A - Ac generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly efficient AC generator which can produce a high output with low noise without complicating the arrangement. SOLUTION: The AC generator for vehicle comprises a tree-phase winding 1, a field winding 2, a three-phase full-wave rectifier 3, a voltage controller 4, and capacitors 51, 52 and 53. Each capacitor 51, 52, 53 is connected between each terminal of the tree-phase winding 1 and the positive pole of the three- phase full-wave rectifier 3. These capacitors 51-53 are charged when negative diodes 34, 35 and 36 connected in series with respective capacitors 51-53 are in conducting state and discharged at the conduction timing of positive diodes 31, 32 and 33 connected in parallel with respective capacitors 51-53. Storage voltages of respective capacitors 51-53 are added to the positive pole voltage of the three-phase full-wave rectifier 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC generator mounted on a passenger car, a truck or the like.

[0002]

2. Description of the Related Art It is important for an alternator mounted on a vehicle to generate as high a voltage as possible at a low rotation speed.
Therefore, various technical improvement efforts have been made so far, such as improving the magnetic circuit for increasing the magnetic flux and increasing the number of windings. In particular, improvements to improve magnetic circuits are still being addressed as constant challenges. In addition, the improvement in increasing the number of windings is fatal that the output does not appear even if the winding amount is increased and the voltage is increased even at low speed rotation because the resistance value and inductance increase, and the output at high speed rotation decreases. There was a problem.

Furthermore, recently, by reducing the number of windings that the induced voltage originally does not reach the rated value, the resistance value and the inductance are kept low, and the output reduction factor due to the impedance drop from low speed to high speed is suppressed. In order to secure the voltage at the low speed rotation, a technique is known in which the semiconductor chopper circuit is used to boost the voltage so that the power can be generated from the low speed rotation.

[0004]

By the way, the above-mentioned conventional technique using the semiconductor chopper circuit requires an expensive control device and a switch device, and therefore cannot be adopted in a relatively inexpensive generator such as for a vehicle. In addition, there is a problem that noise is significantly generated by the chopper circuit, conduction loss by the semiconductor element at the time of a short circuit by the chopper circuit, and Joule loss due to a large current increase, but the output is inefficient even if it can output. There was also the problem of becoming. Therefore,
It is not a complicated method such as a semiconductor chopper circuit that has drawbacks in terms of noise and efficiency, but with a simpler configuration, high efficiency,
An AC generator that can obtain high output with low noise is desired.

The present invention was created in view of the above points, and an object thereof is to provide an AC generator capable of obtaining high output with high efficiency and low noise without complicating the structure. To provide.

[0006]

In the conventional method using a chopper circuit, a multi-phase winding is short-circuited to store inductance energy, and then the flyback voltage generated by opening this is used as the original generated voltage. In addition to that, a high voltage is generated. That is, the energy storage element is used as a means for increasing the voltage. The present inventor pays attention to this point and tries to utilize capacitance instead of inductance. That is, the capacitor is once charged, and then this charging voltage is added to the original generated voltage to generate a high voltage.

In order to solve the above-mentioned problems, the AC generator of the present invention has a multi-phase winding wound around a stator core and a multi-phase winding connected to each terminal of the multi-phase winding. A full-wave rectifier that rectifies the induced AC voltage and a plurality of first capacitors that are connected between each terminal of the multiphase winding and the positive electrode or the negative electrode of the full-wave rectifier are provided.

For example, considering the case where the first capacitor is connected in parallel with the positive diode included in the full-wave rectifier, the first capacitor is charged while the negative diode is conducting and current is flowing. It Next, since the discharge voltage of the first capacitor is added to the output voltage of the multi-phase winding at the timing when the positive diode conducts, the voltage is about twice as high as that when the first capacitor is not used. Can occur. Considering the case where the first capacitor is connected in parallel with the negative diode included in the full-wave rectifier, the first capacitor is charged when the positive diode is conducting and current is flowing. Next, since the discharge voltage of the first capacitor is added to the output voltage of the multi-phase winding at the timing when the negative diode conducts,
It is possible to generate a voltage that is about twice as high as that in the case where the above capacitor is not used.

As described above, by adding the first capacitor, high output can be obtained without complicating the structure. Further, unlike the case where the chopper circuit is used, the conduction loss and the Joule loss due to the semiconductor element do not increase, so that it is possible to maintain and improve the high efficiency. Further, since no compulsory intermittent control is performed by the switching element and the smoothing action is performed by the added capacitor, noise reduction can be achieved.

Further, the above-mentioned first capacitor may be connected not only to the positive side or the negative side of the full-wave rectifier but also to both of them. As a result, in synchronization with the timing at which the positive diodes appear alternately and the timing at which the negative diodes conduct,
Since the first capacitor connected to the positive side of the full-wave rectifier and the first capacitor connected to the negative side of the full-wave rectifier alternately repeat charging and discharging, compared to the case where the first capacitor is not used. , It is possible to generate a voltage of about three times.

The output voltage of the above-mentioned full-wave rectifier is
It is desirable that the charging voltage be lower than the rated charging voltage when the first capacitor is not connected, and that the charging voltage be the rated charging voltage when the first capacitor is connected. Since the output voltage can be increased by using the first capacitor, the number of windings of the multiphase winding can be reduced by the inverse ratio of the increase ratio of the output voltage. Since the resistance and inductance of the multi-phase winding are proportional to the square of the number of windings, if the output voltage is doubled or tripled using the first capacitor, the number of windings of the multi-phase winding Can be reduced to 1/2 or 1/3. Therefore, the resistance and inductance of the multi-phase winding can be significantly reduced to 1/4 or 1/9, and the impedance drop can be significantly reduced. Therefore, high output and high efficiency can be achieved.

Further, a plurality of second capacitors connected to each terminal of the full-wave rectifier in a Δ-connected state may be further provided. By using the second capacitor having such a connection configuration, a phase advance current can be passed through the multiphase winding to reduce the armature reaction, so that the output voltage can be further increased and the power generation efficiency can be increased. It becomes possible to improve.

Further, the AC generator of the present invention rectifies a polyphase winding wound around a stator core and an AC voltage induced in the polyphase winding by being connected to each terminal of the polyphase winding. And a plurality of second capacitors connected to each terminal of the full-wave rectifier in a Δ-connected state. Even when the second capacitor is used independently without combining with the above-mentioned first capacitor, a phase-advancing current is caused to flow through the multiphase winding to reduce armature reaction, resulting in high output and high efficiency. Becomes possible.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A vehicle alternator according to an embodiment of the present invention will be described below in detail with reference to the drawings. [First Embodiment] FIG. 1 is a connection diagram of a vehicle AC generator according to a first embodiment. As shown in FIG. 1, the vehicle AC generator of this embodiment is included in a three-phase winding 1 as a multi-phase winding included in an armature (not shown) and a rotor (not shown). The field winding 2, the three-phase full-wave rectifier 3, the voltage control device 4, and the capacitors 51, 52, 53 are included.

The positive electrode of the three-phase full-wave rectifier 3 has an output terminal (+
B) and the negative electrode is grounded. In this three-phase full-wave rectifier 3, the cathode side is commonly connected to the positive electrode, and the anode side is individually connected to the X-, Y-, and Z-phase terminals of the three-phase winding 1 respectively. , 32, 33, and three negative diodes 34, 35 whose anode side is commonly connected to the negative electrode and whose cathode side is individually connected to each of the X-, Y-, and Z-phase terminals of the three-phase winding 1. And 36.

The capacitor 51 is connected to the X of the three-phase winding 1.
It is connected between the phase terminal and the positive electrode of the three-phase full-wave rectifier 3, that is, in parallel with the positive diode 31. The capacitor 52 is connected between the Y-phase terminal of the three-phase winding 1 and the positive electrode of the three-phase full-wave rectifier 3, that is, in parallel with the positive diode 32. The capacitor 53 is connected between the Z-phase terminal of the three-phase winding 1 and the positive electrode of the three-phase full-wave rectifier 3, that is, in parallel with the positive diode 33.

Further, each phase of the above-described three-phase winding 1 has 8 turns (number of windings "8") to generate a voltage of 14 V at the rated speed when the capacitors 51, 52 and 53 are not provided. ) Assuming that it is necessary, in the present embodiment, the number of turns is set to half, that is, four turns. Further, the capacitors 51, 52 and 53 have a capacitance of 800 μF. An electrolytic capacitor is used in the case of such a large capacity, but since an AC generator for a vehicle has many ripple components, it is desirable to use an electrolytic capacitor for high ripple.

The vehicular AC generator of this embodiment has such a structure, and its operation will be described below. For example, the following description will be made focusing on the X phase and the Y phase of the three-phase winding 1. At the timing when the positive potential appears in the X phase and the negative potential appears in the Y phase of the three-phase winding 1, the positive diode 31 connected to the X phase becomes conductive and the negative diode 34 connected to the X phase becomes It becomes non-conductive. Further, the positive diode 32 connected to the Y phase becomes non-conductive, and the negative diode 35 connected to the Y phase becomes conductive. Therefore, considering the capacitor 51 connected to the X-phase and the capacitor 52 connected to the Y-phase of the three-phase winding 1, a charging current flows through one of the capacitors 52 whose voltage becomes large and the capacitor 52 is charged. It

At the next timing, when the X phase of the three-phase winding 1 shifts to a negative potential and the Y phase shifts to a positive potential, the positive diode 31 connected to the X phase becomes non-conductive and connected to the X phase. The charged negative diode 34 becomes conductive. Further, the positive diode 32 connected to the Y phase becomes conductive, and the negative diode 35 connected to the Y phase becomes non-conductive. Therefore, a charging current flows through one of the capacitors 51 whose voltage becomes large, and the capacitors 51 are charged. Further, the other capacitor 52 charged at the immediately preceding timing is discharged at this timing. Therefore, the terminal voltage (stored voltage) of the capacitor 52 connected in series to this terminal is added to the Y-phase terminal voltage of the three-phase winding 1, and the output is about twice as high as when the capacitor 52 or the like is not used. A voltage can be generated at the output terminal.

In the above description, the X of the three-phase winding 1 is
Focusing on the phase and the Y phase, the same applies to the relationship with other phases, and as a result, the capacitors 51, 52, and 53 are charged in synchronization with the AC voltage generated in each phase of the three-phase winding 1. The discharge is repeated, and an output voltage about twice as high as that of a vehicle AC generator can be obtained.

Thus, the capacitors 51, 52, 53
Since it is possible to generate an output voltage about twice as high as that in the case of not using, the same rated voltage can be generated even if the number of windings of the three-phase winding 1 is halved. For this reason,
The winding impedance, which is inversely proportional to the square of the increase ratio of the number of windings, can be significantly reduced, and the power generation efficiency and the output of the vehicle alternator can be improved.

For example, when the vehicle AC generator of this embodiment was actually prototyped and its characteristics were measured, a vehicle having a conventional structure when the outer diameter of the armature was 110 mm, the rated voltage was 14 V, and the rated current was 80 A. In the AC alternator for use, the output current at idling speed was 40A and the power generation efficiency was 60%, but the output current was 60A and the power generation efficiency was 73%.
Significant effects were obtained in the remarkable improvement of power generation efficiency and high output.

[Second Embodiment] FIG. 2 is a wiring diagram of a vehicle AC generator according to a second embodiment. As shown in FIG. 2, the vehicle alternator of the present embodiment includes a three-phase winding 1, a field winding 2 included in a rotor (not shown), a three-phase full-wave rectifier 3, and a voltage control device. 4, and includes capacitors 51, 52 and 53. This vehicle alternator is shown in Fig. 1.
The difference is that the three positive-electrode-side capacitors 51, 52, 53 included in the vehicle alternator of the first embodiment shown in FIG. 3 are replaced with the three negative-electrode-side capacitors 54, 55, 56. . That is, the capacitor 54 is the three-phase winding 1
Is connected between the X-phase terminal and the negative electrode of the three-phase full-wave rectifier 3, that is, in parallel with the negative diode 34. The capacitor 55 is connected between the Y-phase terminal of the three-phase winding 1 and the negative electrode of the three-phase full-wave rectifier 3, that is, in parallel with the negative diode 35. The capacitor 56 is connected between the Z-phase terminal of the three-phase winding 1 and the negative electrode of the three-phase full-wave rectifier 3, that is, in parallel with the negative diode 36.

The basic operation of the vehicle alternator of this embodiment is the same as that of the vehicle alternator of the first embodiment.
Only the timing at which each of the capacitors 54, 55, 56 is charged and discharged is different. Therefore, the output voltage of the vehicular AC generator can be approximately doubled as compared with the case where these capacitors 54, 55 and 56 are not provided.
As a result, the same rated voltage can be generated even if the number of turns of the three-phase winding 1 is reduced to half, and the winding impedance is greatly reduced, and the power generation efficiency of the vehicle alternator is improved. Higher output is possible.

Further, in this embodiment, each capacitor 5
Since one end of each of 4, 55, and 56 is grounded, it is not necessary to take measures for insulation between the housing, the rear cover, and the like, which facilitates design and improves environmental resistance. The cost can be reduced.

[Third Embodiment] FIG. 3 is a connection diagram of a vehicle AC generator according to a third embodiment. The vehicle alternator shown in FIG. 3 is a combination of the features of the vehicle alternators shown in FIGS. 1 and 2, and is connected to the positive or negative electrode of the three-phase full-wave rectifier 3. It is provided with individual diodes 31 to 36.

For example, focusing on the X phase and the Y phase of the three-phase winding 1, the following description will be given. A positive potential is applied to the X phase of the three-phase winding 1,
At the timing when the negative potential appears in the Y phase, the positive diode 31 connected to the X phase becomes conductive and the negative diode 34 connected to the X phase becomes non-conductive. Also, Y
The positive diode 32 connected to the phase becomes non-conductive,
The negative diode 35 connected to the Y phase becomes conductive.
Therefore, a charging current flows through the capacitor 54 connected to the X phase and the capacitor 52 connected to the Y phase of the three-phase winding 1, and these capacitors 52 and 54 are charged.

At the next timing, when the X phase of the three-phase winding 1 shifts to a negative potential and the Y phase shifts to a positive potential, the positive diode 31 connected to the X phase becomes non-conductive and connected to the X phase. The charged negative diode 34 becomes conductive. Further, the positive diode 32 connected to the Y phase becomes conductive, and the negative diode 35 connected to the Y phase becomes non-conductive. Therefore, a charging current flows through the capacitor 51 connected to the X phase and the capacitor 55 connected to the Y phase of the three-phase winding 1, and these capacitors 51 and 55 are charged. In addition, the two capacitors 52, 5 charged at the previous timing
4 is discharged at this timing. Therefore, two capacitors 52, 54 connected in series to the respective terminal voltages of the X-phase and the Y-phase of the three-phase winding 1 are connected to these terminals.
Each terminal voltage (storage voltage) of
It is possible to generate an output voltage at the output terminal, which is about three times as high as that in the case of not using the above.

In the above description, the X of the three-phase winding 1 is
Focusing on the phase and the Y phase, the same applies to the relationship with other phases, and as a result, each of the capacitors 51 to 56 has a three-phase winding 1
Since charging and discharging are repeated in synchronization with the AC voltage generated in each phase, the output voltage of about 3 times can be obtained as the vehicle AC generator.

As described above, the output voltage can be generated about three times as compared with the case where the capacitors 51 to 56 are not used. Therefore, even if the number of windings of the three-phase winding 1 is set to about ⅓, it is the same. It becomes possible to generate the rated voltage. Therefore, the winding impedance, which is inversely proportional to the square of the increase rate of the number of windings, can be significantly reduced (about 1/9), and the power generation efficiency and the output of the vehicle alternator can be improved. .

[Fourth Embodiment] FIG. 4 is a connection diagram of a vehicle AC generator according to a fourth embodiment. The vehicular AC generator shown in FIG. 4 is different from the vehicular AC generator shown in FIG. 1 in that three capacitors 61, 62 connected to each terminal of the three-phase winding 1 in a Δ-connected state. , 63 are added. These capacitors with relatively small capacitance 6
By adding 1, 62, 63, a leading current can be passed through the three-phase winding 1, so that the reduction of the main magnetic flux due to the armature reaction can be suppressed and the generated voltage can be further increased. become.

In particular, these added capacitors 61,
Since 62 and 63 are not connected to the positive electrode or the negative electrode of the three-phase full-wave rectifier 3, they are not used for the passage of electric power, but only act as symmetric three-phase AC reactive power loads for leading the phase, which is a burden. Has the advantage of being light and having a small durability.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the present invention. For example, in the above-described fourth embodiment, the phase advancing capacitors 61 to 63 are added to the vehicle AC generator of the first embodiment, but as shown in FIG.
In the vehicle alternator of the second embodiment, the capacitors 61 to 61 are provided.
63 may be added, or as shown in FIG. 6, the capacitors 61 to 63 may be added to the vehicle alternator of the third embodiment. Alternatively, as shown in FIG. 7, without using a capacitor connected to the positive electrode or the negative electrode of the three-phase full-wave rectifier 3, the phase advancing capacitors 61 to 63 are used.
You may make it add only. Also in this case, high output and high efficiency can be achieved by reducing the armature reaction.

In each of the above-described embodiments, the case where the number of phases of the multiphase winding is "3" has been described, but a multiphase winding having a larger number of phases may be used.

[Brief description of drawings]

FIG. 1 is a wiring diagram of a vehicle AC generator according to a first embodiment.

FIG. 2 is a wiring diagram of a vehicle AC generator according to a second embodiment.

FIG. 3 is a connection diagram of a vehicle AC generator according to a third embodiment.

FIG. 4 is a connection diagram of a vehicle AC generator according to a fourth embodiment.

FIG. 5 is a connection diagram of a vehicle alternator of a modified example.

FIG. 6 is a connection diagram of a vehicle alternator of a modified example.

FIG. 7 is a wiring diagram of a vehicle alternator of a modified example.

[Explanation of symbols]

1 three-phase winding 2 field winding 3 three-phase full-wave rectifier 4 voltage control device 31, 32, 33 positive diode 34, 35, 36 negative diode 51, 52, 53, 54, 55, 56, 61, 62, 6
3 capacitors

Claims (5)

[Claims] 1. A multi-phase winding wound around a stator core, and a full-wave rectifier connected to each terminal of the multi-phase winding to rectify an AC voltage induced in the multi-phase winding. An alternating-current generator comprising: a plurality of first capacitors connected between each terminal of the multiphase winding and a positive electrode or a negative electrode of the full-wave rectifier. 2. A multi-phase winding wound around a stator core, and a full-wave rectifier connected to each terminal of the multi-phase winding to rectify an AC voltage induced in the multi-phase winding. An alternating-current generator comprising: a plurality of first capacitors connected between each terminal of the multiphase winding and each of a positive electrode and a negative electrode of the full-wave rectifier. 3. The output voltage of the full-wave rectifier according to claim 1, wherein the output voltage of the full-wave rectifier is lower than a rated charging voltage in a state where the first capacitor is not connected, and the first capacitor is connected. An alternating-current generator, which is set so as to have the rated charging voltage in a state. 4. The alternator according to claim 1, further comprising a plurality of second capacitors connected to each terminal of the multiphase winding in a Δ-connected state. 5. A multi-phase winding wound around a stator core, and a full-wave rectifier connected to each terminal of the multi-phase winding to rectify an AC voltage induced in the multi-phase winding. , A plurality of second capacitors connected to each terminal of the multi-phase winding in a Δ-connected state, and an alternating current generator.