JPH11191951A - Generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the output of a generator equipped with permanent magnets from an excessive rise, with a small and highly reliable construction. SOLUTION: The cathode side of a rectifier 120 is composed of Zener diodes 131, 132 and 133. With this construction, even if a rotor has permanent magnets and the fluxes of the permanent magnets interlink with stator windings, the voltage of the output of a generator is laminated to a proper value. Furthermore, a commutation spike preventing Zener diode 134 is provided. Since all the Zener diodes are provided on a radiating fin 122 in common and cooled by the radiation fin 122, the size as a generator will not be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generator particularly suitable for use in an automotive alternator.

[0002]

2. Description of the Related Art In order to achieve a compact, lightweight and high output, it is necessary to generate a high magnetic flux with a small rotor. Therefore, a method of obtaining a high magnetic flux by using a permanent magnet in combination with a field winding is known. However, in this case, there is a drawback that field force control cannot be performed. Therefore, as a method of controlling the magnetic field force, there is a method of adjusting a magnetic flux amount by displacing a part of a magnetic path by using, for example, centrifugal force as disclosed in Japanese Patent Application Laid-Open No. 63-77362.

Further, as disclosed in Japanese Patent Application Laid-Open No. 58-204754 or Japanese Utility Model Laid-Open Publication No. 50-144211, a forward or reverse current can be applied to a field winding used in combination with a permanent magnet. There is something to control.

[0004]

However, the prior art requires a movable part for displacing a part of the magnetic path and a control circuit for controlling the field current. In the event of a failure, the field may not be controlled. SUMMARY OF THE INVENTION It is an object of the present invention to provide a power generation device that is miniaturized and has a highly reliable configuration and prevents an excessive increase in output.

[0005]

In order to achieve the above object, the present invention employs the following technical means. In order to clarify the correspondence with the configuration of the embodiment described later, reference numerals of the embodiment are added in parentheses. According to the first aspect, the rotor is driven through rotation, a stator having a stator core through which a magnetic flux supplied from the rotor is passed, and a stator winding provided in the stator core, and the rotor through the rotor. A permanent magnet that supplies a magnetic flux to the stator core, a field winding that adjusts a magnetic flux supplied from the rotor to the stator core, and a power generation of the stator winding that is connected to the stator winding. A rectifier for rectifying the output to a direct current and outputting the rectified output to a direct current terminal, wherein the rectifier comprises:
A plurality of rectifiers (131, 132, 133, 135, 1
36, 137), and the rectifier includes a Zener diode (131, 132, 133) for limiting a voltage at the DC terminal, and the Zener diode is connected to the other rectifier (135, 135). 136,
137) and technical means called a power generator, which is provided on the radiation fins (121, 122).

In this configuration, the magnetic flux interlinking the stator winding through the stator core is increased or decreased depending on the direction of energization of the field winding. Can be controlled by the current of the field winding. Furthermore, since the rectifier includes a zener diode, even when the output induced in the stator winding excessively increases, power is supplied from the power generator by appropriately selecting the zener voltage of the zener diode. The load can be protected from overvoltage. In addition, since the Zener diode is provided as a rectifier of the rectifier and provided on the radiator fins together with other rectifiers, the size of the power generator is not increased.

In the above configuration, the permanent magnet may be configured to generate a voltage higher than a proper voltage of a load in the stator winding in a state where the current supply to the field winding is cut off. The diode can prevent the overvoltage of the load. Further, a configuration in which a battery is connected to the DC terminal may be employed.

Further, the rectifier includes a positive rectifier (13) for connecting the stator winding and the DC terminal.
5, 136, 137) and a negative-side rectifier (131, 132, 133) for connecting the stator winding to the ground. The Zener diode (131, 132, 133) is connected to the negative-side rectifier. ) Is desirably adopted.

Further, all of the negative side rectifier may be constituted by the Zener diodes (131, 132, 133). Further, both the positive side rectifier and the negative side rectifier are diodes, and the Zener diodes (131, 132, 133) have a lower Zener voltage than the other diodes (135, 136, 137). Configuration.

It is preferable that the rectifier further includes another zener diode (134) connected between the DC terminal and ground and provided on the radiating fin (122). According to this configuration, another Zener diode (134) can be used to absorb the commutation spike voltage at the output end of the generator, and since it is used in combination with the Zener diode described above, other Zener diodes can be used. Diodes do not bear all of the overvoltage.

[0011]

FIG. 1 is a sectional view showing an essential part of a first embodiment of a rotor of a generator to which the present invention is applied. First to third Landel type rotors 1, 2, 3 are shown. A shaft 4 for supporting the rotors 1, 2, and 3, and a stator 5 disposed on the outer periphery of the rotors 1, 2, and 3.

The first rotor 1 has a cylindrical boss portion 11 fixed to the outer periphery of the shaft 4, and first and second claw-shaped magnetic poles 12, 13 disposed on both sides of the cylindrical portion 11. And a field winding 14 arranged on the outer periphery of the cylindrical portion 11. Then, the first and second claw-shaped magnetic poles 12 and 13 have:
As shown in FIG. 2, first and second claw portions 12a and 13a, which extend toward the boss portion 11 and are alternately arranged, are integrally formed. Also, the first and second claws 12a, 13a
Has a trapezoidal shape.

The second and third rotors 2, 3 are provided with a first
, The third and fourth claw-shaped magnetic poles 21 and 2
It comprises second, fifth and sixth claw-shaped magnetic poles 31 and 32. Also,
These third to sixth claw-shaped magnetic poles 21, 22, 31, 3
In FIG. 2, third to sixth claw portions 21a, 22a, 31a, and 32a are alternately arranged as shown in FIG. Then, the first disc-shaped magnet 23 is inserted between the third and fourth claw-shaped magnetic poles 21 and 22, and the second disc-shaped magnet 33 is inserted into the fifth and sixth claw-on magnetic poles 31. , 32. Further, the first and second magnets 23, 33
Are magnetized and arranged in the axial direction such that the opposing surface becomes the N pole.

Then, the first to third rotors 1, 2,.
The outer circumference of 3 has substantially the same diameter. The shaft 4 is rotated by an engine (not shown) via a belt, and has a commutator (not shown) to which a field winding 14 is connected at one end. The stator 5 includes a stator core 51
And a three-phase concentrated stator winding 5 wound in the core 51.
And 2. The core 51 has three times as many slots as the number of poles of the first and second claws 12 a and 13 a of the first rotor 1.

Reference numeral 6 denotes a sleeve made of a non-magnetic material, which is fixed to the outer periphery of the shaft 4 as shown in FIG. 1, and the first magnet 23 of the second rotor 2 and the fourth The claw-shaped magnetic pole 22, the fifth and sixth claw-shaped magnetic poles 31 and 32 of the third rotor 3, and the second magnet 33 are arranged. Then, the first to sixth claw portions 12a, 13a, 21a, 22a, 31a, 31a, of the first to third rotors 1, 2, 3 are formed.
Numerals 32a denote the same number of magnetic poles, and the positions of the magnetic poles (that is, the positions of the claws) are at substantially the same angular position but slightly shifted from each other as shown in FIG. That is, the first claw portion 12a of the first rotor is shifted by λ / 4 from the fourth claw portion 22a of the adjacent second rotor 2, and the fifth claw portion of the third rotor 3 is shifted. 31a is the fourth claw 2
2a is shifted by λ / 2. Here, λ is a so-called slot ripple wavelength.

As shown in FIG. 3, the slit ripple includes a slot of the core 51 of the stator 5 and first to third slots.
And the first and sixth claws of the rotors 1, 2, and 3, and the slot ripple wavelength is equal to the pitch of the slots of the core 51. Next, the switching means 7 shown in FIG. 4 will be described. The switching means 7 includes transistors 71, 72, 73, 74, and the transistors 71, 72 and transistors 73, 7
4 are connected in parallel with each other. Also, the transistor 7
The field winding 14 is connected between the terminals 1 and 72 and between the transistors 73 and 74.

As shown in FIG. 5, a signal is sent to the bases of the transistors 71 to 74 to change the direction of the current flowing through the field winding 14 and to change the direction of the field winding 1.
4 is to control the current flowing through the circuit 4. In the above basic configuration, magnetic flux generation of the first rotor 1 (stator core 51
Capacity) is set substantially equal to the magnetic flux generation ability of the second rotor 3 and the third rotor 3 added. In other words, the first to sixth claw portions 12 shown in FIG.
Regarding the outer peripheral area of the a, 13a, 21a, 22a, 31a, 32a, (the outer peripheral area of the first and second claws 12a, 13a) ≒ (the outer peripheral area of the third and fourth claws 21a, 22a) + (Outer peripheral area of fifth and sixth claw portions 31a and 32a)
Is in a relationship.

Next, the operation of the above configuration will be described. When the load is large and the output of the generator itself is required, the magnetic flux generated by the permanent magnets 23 and 33 of the second and third rotors 2 and 3 flows through the stator core 51 and the permanent magnets. A current flows through the field winding 14 via the switching means 7 so that the magnetic fluxes of the magnetic fluxes 23 and 33 flow in the same direction as the flow direction of the core 51. That is, the transistors 72 and 73 of the switching means 7 are turned off and the transistors 71 and 74 are turned on.

The stator winding 52 has second and third windings.
Are added by the magnetic fluxes generated by the permanent magnets 23 and 33 of the rotors 2 and 3 and the magnetic fluxes generated by the field winding 14 of the first rotor 1. Further, the switching means 7 operates such that the battery has a predetermined voltage.
The current flowing through the field winding 14 is controlled.

That is, when the field winding 14 needs a magnetic flux larger than the magnetic flux of the three permanent magnets 23, 33 of the second and third rotors 2, 3, the magnetic flux of the permanent magnets 23, 33 is required. The current flows through the field winding 14 so that a magnetic flux in the same direction as the magnetic flux flows. Next, when the load is small and the output of the generator is sufficient with the magnetic flux of the permanent magnets 23 and 33 of the second and third rotors 2 and 3, the battery is overcharged or the generator is The core 51 of the permanent magnets 23 and 33 is attached to the field winding 14 of the first rotor 1 so as not to be a load.
The field current is reversed with respect to the above so as to flow a magnetic flux in the opposite direction to the magnetic field. That is, the transistors 71 and 74 of the switching means 7 are turned off and the transistors 72 and 73 are turned on.

Therefore, the predetermined magnetic flux generated from the permanent magnets 23 and 33 is canceled by the magnetic flux generated in the field winding 14 of the first rotor 1. Further, by controlling the current flowing through the field winding 14 by the switching means 7 so as to control the battery voltage to a predetermined value, the smaller the load, the smaller the amount of charge to the battery. The current flowing through the magnetic winding 14 is increased to largely cancel the magnetic flux of the permanent magnets 23 and 33.

As described above, since the first rotor 1 must have a reverse magnetic flux generating ability capable of canceling out the total amount of magnetic flux generated by the permanent magnets 23 and 33, the magnetic fluxes of these two types of field elements are considered as a design principle. It is necessary to select the generation capabilities approximately equal, and from the principle of electric machine design that the value of the air gap magnetic flux density is generally a fixed universal upper limit of about 8 K Gauss, (first,
Areas of the second claws 12a and 13a) ≒ (areas of the third and fourth claws 21a and 22a) + (fifth and sixth claws 31)
a, 32a).

Next, the operation will be described with respect to the slight displacement of the claws described with reference to FIG. It is well known that electromagnetic noise is generated when a rotating electric machine is operated, not limited to a generator, and one of the sources of the vibration is a variation in the magnetic resistance of the stator core and the magnetic poles of the rotor that are opposed to each other. It is well known that things exist. Due to the irregular magnetic resistance, pulsation of the inductance energy is generated, and thus a torque is generated which is superimposed on the average torque between the stator and the rotor and pulsates the average torque. This is called slot ripple torque (or detent torque) shown in FIG. 3, and it is well known that it is a dominant component as a source of electromagnetic noise. According to the present invention, in order to eliminate such torque unevenness, the above-described magnetic resistance unevenness (slot ripple torque) is generated by shifting the magnetic poles of the rotor with respect to the teeth (not shown) of the armature core or the slots. Is to be minimized when rotating. Generally, the shift width is λ with respect to the slot ripple wavelength λ.
If / 2 is selected, the peaks and valleys cancel each other, and the slot ripple is minimized.

Normally, in consideration of the fact that the power generation of the generator when the vehicle is actually used is small in full load state and large in half load state, the permanent magnet magnetic poles 23, 3 which should be magnetized at this time are
3 are shifted from each other by λ / 2. When the load is further required, the claw portions 12a and 13a of the first rotor 1 are magnetized in any case where the region is hardly required. Second, third
In order to reduce the overlap of the slot ripple with the claw portions 21a, 22a, 31a, 32a of the rotor of the first rotor, the first claw portion 12a is formed by the fourth claw portion 22a and the fifth claw portion 31a. Should be located between

With the above configuration, the generated power can be adjusted by adjusting the exciting current. The two cores, each with a long magnetic path, each with a long magnetic path, a heavy core winding, and an excitation current must be applied to each of them. It goes without saying that the weight of the rotor is reduced, the amount of heat generated by the rotor and the power consumption are suppressed, and the cooling means becomes simpler.

FIGS. 6 and 7 show a second embodiment of a generator rotor, in which a fourth rotor 8 is used instead of the second and third rotors 2 and 3. FIG. The fourth rotor 8 is integrally formed with a yoke cylindrical portion 81 fixed to the end face of the second claw-shaped magnetic pole 13 of the first rotor 1 as shown in FIG. Six trapezoidal projections 82 formed and arranged at equal intervals, and 6 fixed between these projections 82
And a trapezoidal permanent magnet 83. The protrusions 82 and the permanent magnets 83 are alternately arranged, similarly to the arrangement of the first and second claw portions 12a and 13a of the first rotor 1.

A band 84 of a ring-shaped nonmagnetic material is used.
Is provided on the outer periphery of the permanent magnet 83 to prevent the permanent magnet 83 from scattering toward the radially outer periphery. The protrusion 82 of the fourth rotor 8 is shifted by λ / 2 from the claw 12a of the first rotor 1 as in the first embodiment. Also,
By forming a space on the inner peripheral side of the cylindrical portion 81, a resin-molded centrifugal / axial flow mixing fan 85 fixed in the space and on the shaft 4 can be provided. The fan 85 fixed to the shaft 4 protrudes from the end face of the fourth stator 8, and can cool the field winding 14 and the stator winding 52.

FIGS. 8 and 9 show a third embodiment of the generator rotor. The fifth rotor 9 has a plurality of rectangular permanent magnets 91 and is disposed between the permanent magnets 91. And a magnetic pole piece 92 made of a cold-forged formed mild steel tapering toward the shaft 4 side. The magnet 91 and the pole piece 92 are combined to form a cylindrical shape. Reference numeral 93 denotes a non-magnetic metal plate formed by press-drawing, which comprises a cylindrical portion 93 a fixed on the shaft 4 and a pair of disk portions 93 bb disposed on end faces of the permanent magnet 91 and the pole piece 92. Become. Also,
As shown in FIG. 4, a permanent magnet 91 is provided on the disc 93b.
Hole 9 with which the cylindrical portion 91a formed on the axial end face of the
3c is provided.

The projection 91a of the permanent magnet 91 engages with the hole 93c of the disk 93b of the metal plate 93,
It is possible to prevent the permanent magnet 91 from scattering to the radially outer peripheral side. The disk 93 b of the metal plate 93 and the pole piece 9
2 is press-welded to the pole piece 92 to form a metal plate 93.
It is fixed to.

Further, a cooling fan 10 having a magnetic body 10a rotatably fixed to the shaft 4 is disposed at a predetermined interval δ (δ is appropriately determined based on required magnetic force, machining accuracy, etc.). Has been established. The fan 10 follows the magnetic flux leaked from the magnet 91 of the fifth rotor 9 and rotates following the magnetic force. However, when the rotation speed increases, the fan 10 balances the wind pressure of the fan blades and does not follow the predetermined rotation or more. It has become. In other words, since a large centrifugal force is not applied unnecessarily to the blades, the fan can be designed drastically large, the cooling effect can be significantly improved, and the basic effect that the generator can be downsized more easily can be achieved. It will be.

In the above configuration, it is not mentioned whether the rotor having the permanent magnet and the rotor having the field winding should be disposed before or after the shaft. It is needless to say that the arrangement should be as small as possible. For example, the rectifier-located side or the engine heated large side generally has a high temperature, so that the rotor having the permanent magnet is preferably provided on the opposite side.

Next, referring to FIGS. 10 and 11, a fourth embodiment of the configuration of the power generator to which the present invention is applied and the rotor of the generator will be described. The fifth rotor 100 includes a shaft 101 driven by an engine,
1 includes a magnetic pole 102, a field winding 103, and a permanent magnet 104 provided on the outer periphery. The magnetic pole 102 has a projection 102a provided on the radially outer peripheral side and at equal intervals, and a flange 102b provided at the tip of the projection 102a and on the peripheral side.

The field windings 103 are wound between the adjacent protruding portions 102a so that the directions of currents flowing through the field windings 103 are alternately different. Further, the arc-shaped permanent magnet 104 is arranged on the outer peripheral side of the field winding 103, and the adjacent magnets have the same polarity at the circumferential end faces. The armature 110 has the first
As in the embodiment, the rotor 100 faces the outer periphery of the rotor 100,
A three-phase Y-connection winding is applied to this, and the AC output of the armature winding 111 is connected to the rectifier 120.

The rectifier 120 is a three-phase full-wave rectifier, and includes a positive-side discharge heat fin 121 and a negative-side radiator fan 1.
The negative-side radiation fins 122 are in contact with a generator housing (not shown) and have good heat radiation.
Zener diodes 131, 132, 133, and 134 are fixed to the negative-side radiation fins 122,
Each of these was selected at about 16V for a maximum battery voltage of 15.3V and an output wire harness drop of 0.5V. The diodes 135, 136, and 137 which are avalanche type but are usually used for vehicles are fixed to the positive-side radiation fins 121, and their zener voltages (falling voltages) are about 300V. . When the demand for the load 140 of the vehicle decreases, the generator output voltage increases, so that it is necessary to weaken the field, and the current of the field winding 103 is reduced by a conventionally known voltage control device. When the load demand decreases extremely, the field winding 103
Even if the current is set to 0FF, the generator voltage is higher than the proper charging voltage (for example, 15.3 V) of the battery 150 due to the magnetomotive force of the permanent magnet 104, which may cause overcharging.
In this configuration, the negative-side Zener diodes 131, 132,
133 cuts the voltage at 16V. Diodes 135, 136 and 137 have a forward voltage drop of about 0.8V
And the output voltage is 16V-0.8V = 15.
It becomes 2V and becomes an appropriate voltage.

By this operation, the Zener diode 13
Although short-circuit current flows through 1, 132, and 133, a loss occurs. However, since the negative-side fins 122 provide good heat radiation to a housing (not shown), excessive temperature rise does not occur. As described above, since the output of the permanent magnet 104 does not cause overcharging of the battery 150, conversely, the ratio of the permanent magnet 104 can be increased, that is, the ratio of the winding electromagnet can be reduced, and the size and weight can be reduced. A generator can be provided.

The Zener diodes 131, 132,
The burden of the short-circuit current of 133 and 134 will be described. That is, due to the presence of the forward voltage drop of the diodes 135, 136, and 137, 131, 132, and 133 fall faster than 134, and the output of the permanent magnet of the generator is received by the zener diode 134 alone and short-circuited. No inconvenient operation occurs.

In addition to the above effects, the Zener diode 134 for absorbing the commutation spike voltage at the generator output terminal may be the same element as the rectifying Zener diodes 131, 132, and 133. In addition, there is an advantage that the manufacturing cost can be reduced by arranging four. Although various second, third, fourth and fifth rotors 2, 3, 8, and 100 using permanent magnets are shown in the first to fourth embodiments, these permanent magnets and magnetic poles are used. The arrangement is not limited to this.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a main part of a generator used in a power generator of the present invention.

FIG. 2 is a plan view showing a main part of the rotor of the first embodiment.

FIG. 3 is a characteristic diagram showing torque unevenness with respect to a rotation angle.

FIG. 4 is an electric circuit diagram showing switching means in the first embodiment.

FIG. 5 is a waveform diagram showing an input waveform to a switching means.

FIG. 6 is a sectional view showing a main part of the second embodiment.

FIG. 7 is a front view showing a main part of a rotor according to a second embodiment.

FIG. 8 is a sectional view showing a main part of a third embodiment.

FIG. 9 is a front view showing a main part of a rotor according to a third embodiment.

FIG. 10 is an electric circuit diagram showing a main part of a power generator to which the present invention is applied.

FIG. 11 is a sectional view showing a rotor according to a fourth embodiment.

[Explanation of symbols]

 1, 2, 3 First to third rotor 11 Boss 12, 13 First and second claw-shaped magnetic poles 14 Field winding 21, 22 Third and fourth claw-shaped magnetic poles 31, 32 Fifth , Sixth claw-shaped magnetic pole 23 first magnet 33 second magnet 5 stator 52 stator winding 7 switching means 131, 132, 133, 134 Zener diode

Claims (7)

[Claims] A rotor that is driven to rotate, a stator having a stator core through which magnetic flux supplied from the rotor passes, and a stator winding provided on the stator core; A permanent magnet that supplies a magnetic flux to the stator core; a field winding that adjusts a magnetic flux supplied from the rotor to the stator core; A rectifier for rectifying an output to a direct current and outputting the direct current to a direct current terminal; the rectifier includes a radiation fin and a plurality of rectifiers; and the rectifier has a zener diode for limiting a voltage at the direct current terminal. Wherein the Zener diode is provided on the radiation fin together with the other rectifier. 2. The power generator according to claim 1, wherein the permanent magnet generates a voltage higher than a proper voltage of a load in the stator winding in a state where the current supply to the field winding is cut off. . 3. The power generator according to claim 1, wherein a battery is connected to the DC terminal. 4. The rectifier comprises: a rectifier on the positive side that connects the stator winding to the DC terminal; and a rectifier on the negative side that connects the stator winding to ground. The power generator according to any one of claims 1 to 3, wherein the zener diode is included in the negative electrode rectifier. 5. The power generator according to claim 4, wherein the whole of the negative side rectifier is constituted by the Zener diode. 6. The device according to claim 4, wherein both the positive rectifier and the negative rectifier are diodes, and the Zener diode has a lower Zener voltage than the other diodes. A power generator according to any one of the above. 7. The rectifier according to claim 1, further comprising another zener diode connected between the DC terminal and ground and provided on the radiation fin.
The power generator according to any one of claims 1 to 6.