JPH04347566A - Brushless synchronous machine - Google Patents

Abstract

PURPOSE:To provide only an armature coil as a coil of a stator core by connecting an impedance element of 3-phase star connection to a leading end of an armature coil of 3-phase star connection and then connecting a power supply at the intermediate point between the leading end and impedance element. CONSTITUTION:Armature coils U, V, W of the centralized full node winding or a winding profile conforming thereto are wound around an iron core in the 3-phase star connection mode, an impedance element 8 of the 3-phase star connection is connected to the leading end thereof and a stator excitation power supply 7 is connected between the neural point (n) of the impedance element 8 and the neutral point N of the armature coils U, V, W to form a closed circuit. A rotor coil is provided with rotor exciting coils 6a to 6c which are magnetically connected with as many poles as three times or five times the number of the poles of the armature coils. Electromotive forces of these coils are converted into DC by rectifiers 9a to 9c and thereafter supplied to a rotor field coil 5. Thereby, only the armature windings U, V, W are provided as the coils of stator iron core.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to brushless synchronous machines, and more particularly to brushless synchronous generators and brushless synchronous motors.

0002

[Prior Art] Conventional synchronous machines have a structure in which an exciter is installed on the rotating shaft of the main body of the synchronous machine as a technique for making the machine brushless. A system has emerged in which this exciter is omitted for the purpose of simplifying the system.

For example, in a first method, a main armature winding and a stator excitation winding having a different number of poles from the armature winding are wound around the stator core, and the main armature winding is wound around the rotor core. By winding a rotor field winding having the same number of poles as the child winding and a rotor excitation winding that is magnetically coupled to the stator excitation winding,
There is a method in which the voltage in the rotor excitation winding induced by the magnetic field of the stator excitation winding is converted into direct current by a rectifier provided in the rotor core, and then supplied to the rotor field winding.

[0004] This type of system is used in synchronous generators as disclosed in Japanese Patent Application Laid-open Nos. 62-23348 and 1983.
Those described in British Patent No. 220746, British Patent No. 941482, and British Patent No. 1038472 are known.

[0005] As a second method, a structure in which the stator excitation winding is omitted by having the main armature winding also serve as the function of the stator excitation winding in the first method is disclosed in Japanese Patent Laid-Open No. 55
It is disclosed in Japanese Patent No.-2327.

[0006]

However, the conventional brushless synchronous machine described above has the following problems.

In the first system, two types of windings, the main armature winding and the stator excitation winding, must be wound around the stator core. The large number of types complicates the arrangement of the windings and increases manufacturing costs.

In those belonging to the second system, although the types of windings can be reduced, on the other hand, the armature winding has a unique double star connection with a midpoint, and therefore,
As shown in the above-mentioned Japanese Patent Laid-Open No. 55-2327, there are problems such as the need for special design consideration in setting the winding pitch of the armature winding.

The present invention has been devised in view of the above-mentioned problems, and the stator core windings are only armature windings that are extremely efficient in manufacturing, thereby reducing manufacturing costs. The aim is to provide an inexpensive brushless synchronous machine.

0010

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a three-phase star connection for an armature winding in a winding mode similar to concentrated full-pitch winding or concentrated full-pitch winding in a stator core. An impedance element forming a three-phase star connection is connected to the lead-out end of this armature winding, and fixed between the neutral point of this impedance element and the neutral point of the armature winding. Sub-excitation power supplies are connected to form a closed circuit including these stator excitation power supplies, the armature winding, and the impedance element.

[0011] The rotor core has three poles, which is the number of poles of the armature winding.
A rotor excitation winding that is magnetically coupled with twice and five times the number of poles, and a rotor excitation winding that is provided after the electromotive force of this rotor excitation winding is converted into DC and has the same number of poles as the armature winding. The rotor field winding is wound around the rotor core, and the rotor core is provided with a rectifier for converting the electromotive force of the rotor excitation winding into direct current.

0012

[Operation] The operation when the present invention is applied to a synchronous generator will be explained below.

First, when a small amount of direct current stator excitation current is applied to each phase of the armature winding from the stator excitation power source during no load, the stator excitation current joins the neutral point of the impedance element. Then return to the stator excitation power supply again. At this time, the magnetic field generated by the stator excitation current flowing through the three-phase armature winding (hereinafter referred to as stator excitation magnetic field) is generated by the concentrated full-pitch winding or the similar concentrated full-pitch winding of the armature winding. Due to the wire configuration, the number of poles is three times that of the armature winding. When the rotor is rotated here, an electromotive force is induced in the rotor excitation winding due to magnetic coupling with the number of poles three times the number of poles of the armature winding. This electromotive force supplies a DC rotor field current to the rotor field winding through a rectifier, thereby generating a main magnetic field. Since the armature winding is magnetically coupled to the rotor field winding, an output voltage is induced in the armature winding.

[0014] This output voltage causes a three-phase alternating current (hereinafter referred to as an impedance current) to flow through the impedance elements forming a three-phase star connection. The armature reaction magnetic field generated by the impedance current flowing through the armature winding is the fifth spatial harmonic magnetic field, that is, the number of poles of the armature winding due to the concentrated full-pitch winding or the winding mode similar to concentrated full-pitch winding. It contains five times the number of poles. This fifth spatial harmonic magnetic field becomes a magnetic field that rotates in the opposite direction to the rotation direction of the rotor, and induces an electromotive force in the rotor excitation winding that is magnetically coupled.

As a result, the electromotive force and rotor field current induced in the rotor excitation winding are due to the stator excitation magnetic field due to the stator excitation current, and the fifth spatial harmonic magnetic field in the armature reaction magnetic field due to the impedance current. The main magnetic field is strengthened, which in turn increases the output voltage induced in the armature winding. When the output voltage increases, the impedance current, the fifth spatial harmonic magnetic field, the electromotive force of the rotor excitation winding, the main magnetic field, etc. increase and strengthen, and this is repeated to establish the output voltage in a self-excited manner. At this time, if the stator excitation current is made variable, the output voltage under no load can be adjusted as desired.

Next, when a three-phase load is applied, a composite current of the impedance current and the load current flows through the armature winding as an armature current. The armature reaction magnetic field generated by this armature current also includes a fifth spatial harmonic magnetic field due to the concentrated full-pitch winding or the winding mode similar to the concentrated full-pitch winding of the armature winding. Induces an electromotive force in the excitation winding. Therefore, the electromotive force of the rotor excitation winding is increased by adding the electromotive force due to the fifth spatial harmonic magnetic field due to the load current to the electromotive force under no load, and the rotor field current increases. Since the strength of the fifth spatial harmonic magnetic field under load is proportional to the magnitude of the load current, the rotor field current also increases or decreases as the load current increases or decreases, suppressing fluctuations in the output voltage. That is, the output voltage compensation function essential to a synchronous generator is automatically performed, and the output voltage is kept constant.

In the case of a single-phase load, the fifth spatial harmonic magnetic field contained in the alternating armature reaction magnetic field due to the single-phase AC load current is utilized, so it is the same as in the case of a three-phase load.

The present invention can be operated as a synchronous motor when power is supplied to the armature winding from the outside.

Note that the above-mentioned effect is the same even when the stator excitation power source is alternating current. Further, the stator excitation current only circulates through a closed circuit consisting of the stator excitation power source, the armature winding, and the impedance element, and does not affect the load. Since the numbers of poles of the stator excitation magnetic field, the fifth spatial harmonic magnetic field, and the main magnetic field are different from each other, their influence on each other is extremely small, and the desired output can be obtained.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a synchronous generator will be described with reference to the drawings.

In FIG. 1, U, V, and W are U, V, and W phases of a three-phase armature winding. As shown in Fig. 2, the armature windings U, V, and W are wound in a two-pole, three-phase manner in a concentrated full-pitch winding manner within stator slots 2 formed on the inner circumference of the stator core 1. As shown in FIG. 1, the lead-out ends of each phase are connected to the load via output terminals 10 to 12 in a star connection. Further, an impedance element 8 forming a three-phase star connection is connected to the lead-out ends of the armature windings U, V, and W. A DC stator excitation power source 7 is connected between the neutral point N of the armature windings U, V, W and the neutral point n of the impedance element 8, and this stator excitation power source 7 and the armature winding U , V, W and the impedance element 8 form a closed circuit.

On the other hand, in the rotor R, as shown in FIG. 2, a rotor slot 4 is formed in the rotor core 3, and the rotor field winding 5 and the rotor excitation winding 6a, 6b, and 6c are wound. The rotor field winding 5 is wound so as to form the same number of poles (two poles) as the armature windings U, V, and W. The rotor excitation winding 6a is the armature winding U,
It is wound with a winding pitch that magnetically couples with the number of poles 3 times (6 poles) and 5 times (10 poles) the number of poles of V and W, respectively, and connected to the AC input side of the rectifier 9a. Further, after the rotor excitation windings 6b and 6c are similarly applied, the rectifier 9a.
The DC output sides of 9b and 9c are connected in parallel to each other, and the rotor field winding 5 is connected to the DC output end. Rectifier 9a, 9b
, 9c are each attached to the rotor core 3, and are in the form of a rotating rectifier that rotates together with the rotor core 3.

Next, the operation of the brushless synchronous generator having the above configuration will be explained. First, when there is no load, a small DC stator excitation current iou,i is supplied from the stator excitation power supply 7.
ov and iow are provided to armature windings U, V, and W. The stator excitation currents iou, iov, and iow join the neutral point n of the impedance element 8 and return to the stator excitation power source 7. At this time, the stator excitation magnetic field Ho generated by the stator excitation currents iou, iov, and iow flowing through the three-phase armature windings U, V, and W is caused by the concentrated full-pitch winding of the armature windings U, V, and W. Therefore, the number of poles is three times the number of poles of the armature windings U, V, and W, that is, six poles are formed. This is analyzed below.

FIG. 4 shows the arrangement of each phase of the armature winding and the directions of stator excitation currents iou, iov, and iow. Further, if the armature windings U, V, and W shown in FIG. 4 are expanded in the θ direction, and the square wave magnetic field distribution expressed in a Fourier series for the U phase is shown as shown in FIG. 3. In FIG. 3, the gap between the stator S and the rotor R is omitted.

As mentioned above, the armature winding U with concentrated full-pitch winding
The magnetic field distribution according to It becomes a square wave. However, the magnetic saturation of the magnetic path is ignored.

Using the center point 0 of the square wave as a base point, the magnetic field strength Hou at an arbitrary point P at a distance of θ (rad) in electrical angle from this 0 point is expressed in a Fourier series as follows. In this case, the stator excitation currents iou, iov, iow are
Since it is a direct current, iou≡Io(A)〈average value〉■
Substituting into the formula yields . Furthermore, concentrated full-pitch winding armature windings V and W (
When (V phase) iov≡Io(A) (W phase) iow≡Io(A) flows in (the number of turns is the same as U phase), the magnetic field strength of each phase is expressed as Hov and H, respectively.
When ow is assumed, it becomes . Since the stator excitation magnetic field Ho is the sum of the equations (1), (2), and (2), the following equation is obtained. Ho=Hou+Hov+How ■From the formula, the stator excitation magnetic field Ho is the first term -Hom c
It can be seen that os3θ, that is, six poles are formed. Figure 5
is a graphical representation of the above analysis.

When the rotor R is rotated, an electromotive force er3 is induced in each of the rotor excitation windings 6a, 6b, and 6c, which are magnetically coupled to the six poles of the stator excitation magnetic field Ho. This electromotive force er3 provides a rotor field current if to the rotor field winding 5 through the rectifiers 9a, 9b, and 9c, thereby generating a two-pole main magnetic field. Since the armature windings U, V, W are magnetically coupled to the rotor field winding 5, a small output voltage is induced in the armature windings U, V, W. Due to this output voltage, three-phase AC impedance currents izu, izv, izw flow through the circuit consisting of the armature windings U, V, W and the impedance element 8 as armature currents iau, iav, iaw under no load, An armature reaction magnetic field is generated. This armature reaction magnetic field is generated by the armature windings U and V.
, W are concentrated full-pitch windings, so they contain a fifth spatial harmonic magnetic field, that is, a ten-pole component. This is analyzed below.

Armature current iau (
Letting the magnetic field generated by A) be Hau, the equation (2) can be rewritten as follows.

[Other 6/]

[Other 11/]

[Other 7/] Furthermore, the armature winding V of concentrated full-pitch winding is wound around the stator S at positions shifted by 2π/3 (rad),
W is the armature current shown by the following formula,

When [Other 8/] flows, the magnetic field of each phase is Hav
, Haw, then

[Other 9/] becomes. Since the magnetic field Ha due to the three-phase armature winding with concentrated full-pitch winding is the sum of formulas ■, ■, and ■, the following formula is obtained.

[Other 10/] From the formula ▲10▼, armature current iau, iav
, iaw, the armature reaction magnetic field Ha is composed of the fundamental wave magnetic field 3/2 Hamsin (ωt-θ) in the first term, the fifth spatial harmonic magnetic field in the second term, the seventh spatial harmonic magnetic field in the third term, etc. It consists of odd-numbered spatial harmonic magnetic fields, and based on the sign of the phase angle, the 5th spatial harmonic magnetic field rotates in the opposite direction to the fundamental wave magnetic field, and the 7th spatial harmonic magnetic field rotates in the same direction as the fundamental wave magnetic field. I understand that.

The present invention utilizes the fifth spatial harmonic magnetic field derived from the above analysis results. That is, the rotor excitation windings 6a, 6 are wound so as to be magnetically coupled with the number of poles (10 poles) that is five times the number of poles of the armature windings U, V, W.
An electromotive force er5 is induced in each of b and 6c by the fifth spatial harmonic magnetic field (10 poles) in the armature reaction magnetic field. This electromotive force er5 is applied to the rotor field winding 5 via rectifiers 9a, 9b, and 9c.

As a result, the rotor field current if is equal to the electromotive force er
The electromotive force er5 is added to the electromotive force er5, which increases the main magnetic field, which in turn increases the output voltage induced in the armature winding. When the output voltage increases, the impedance currents izu, izv, izw, the fifth spatial harmonic magnetic field, the electromotive force er5, the main magnetic field, etc. increase and strengthen, and this is repeated to establish the output voltage in a self-exciting manner. At this time, if the stator excitation currents iou, iov, and iow are made variable, the output voltage during no-load can be arbitrarily adjusted.

Next, when a three-phase load is applied, the impedance currents iou, iov, iow and the load currents iu, iv, iw
The combined current flows through the armature windings U, V, and W as armature currents iau, iav, and iaw. The generation and effect of the fifth spatial harmonic magnetic field due to the armature currents iau, iav, and iaw during three-phase loads are the same as in the case of no load, but the generation of the fifth spatial harmonic magnetic field by the armature currents iau, iav, and iaw is the same as in the case of no load, but the The power er5 is the impedance current izu, iz due to the action of the fifth spatial harmonic magnetic field due to the load currents iu, iv, iw.
It increases in addition to the action of the fifth spatial harmonic magnetic field caused by v, izw, and the rotor field current if increases compared to when there is no load. The strength of the fifth spatial harmonic magnetic field under load is proportional to the magnitude of the load currents iu, iv, iw, so as the load current increases or decreases, the rotor field current if also increases or decreases, suppressing fluctuations in the output voltage. suppress. That is, stator excitation current iou,i
Even if ov and iow are kept constant, the output voltage compensation function, which is essential for a synchronous generator, is automatically performed and the output voltage is kept constant. At this time, the stator excitation current is iou,i
By making ov and iow variable, the output voltage can be arbitrarily adjusted under load as well as under no load.

Even in the case of a single-phase load, in the output mode in which the single-phase load is connected to two terminals selected from output terminals 10 to 12, the fifth spatial harmonic in the alternating armature reaction magnetic field due to the single-phase AC load current Since it uses a magnetic field, it is the same as the three-phase case described above.

The stator excitation currents iou, iov, iow only circulate through a closed circuit consisting of the stator excitation power supply 7, the armature windings U, V, W, the impedance element 8, etc., and do not affect the load.

Furthermore, the winding mode of the rotor excitation winding in the present invention is not limited to the above embodiment. FIG. 6 shows developed diagrams of various embodiments of rotor excitation windings that are applied when the armature windings U, V, and W are two poles.
The embodiment shown in FIGS. 1 and 2 adopts FIG. 6(d). Figures 6(a), (b), (c), and (d) show 8-pole, 8-pole, 10-pole, and 6-pole windings, respectively, divided as appropriate without changing the winding pitch, and connected to a rectifier. , both stator excitation magnetic field (6 poles) and 5th spatial harmonic magnetic field (
This is a typical example in which a rotor field current if can be provided by magnetically coupling with two types of magnetic fields having different numbers of poles (10 poles). In addition, it is also possible to wind two types of rotor excitation windings with different winding pitches, a 10-pole winding and a 6-pole winding, and connect each to a rectifier, which can achieve the desired characteristics and manufacturing cost. You can make a selection by taking these factors into consideration.

Further, in the embodiment shown in FIGS. 1 and 2, the armature windings U, V, and W have been described as having concentrated full-pitch windings, but the armature windings in the present invention are The line form is not limited to this. That is, from a practical standpoint, a winding mode similar to concentrated full-pitch winding can be adopted. The winding mode according to the concentrated full-pitch winding described here is to include the fifth spatial harmonic magnetic field in the armature reaction magnetic field due to the armature current, and at the same time to increase the number of poles of the armature winding in the stator excitation magnetic field Ho. No. 3
Refers to any winding configuration in which the winding coefficient of the armature winding is appropriately selected with the intention of forming twice the number of poles. For example, Figure 7
1 shows another embodiment of the winding mode of the armature winding according to the present invention, in which distributed full-pitch winding is distributed over two adjacent stator slots. . The fifth spatial harmonic magnetic field in the armature reaction magnetic field and the stator excitation magnetic field Ho become weaker as the armature windings U, V, and W are distributed more widely, but in the embodiment shown in FIG. This shows that distributed winding is also possible when the thickness is selected within a practical range.

The present invention can also be operated as a synchronous motor when three-phase power is externally supplied to the armature windings U, V, and W.

Note that when the stator excitation power source is an alternating current, the stator excitation magnetic field Ho becomes an alternating magnetic field, but the above effect is the same.

Since the numbers of poles of the stator excitation magnetic field Ho, the fifth spatial harmonic magnetic field, the main magnetic field, etc. are different, their influence on each other is extremely small, and the desired output can be obtained.

[0039]

As described above, according to the present invention, it is possible to realize a brushless synchronous machine in which only the armature winding is used as the winding around the stator core. Furthermore, since the armature winding has a winding mode that is extremely efficient in terms of manufacturing, such as concentrated full-pitch winding or similar to concentrated full-pitch winding, manufacturing costs can be reduced. This effect is particularly remarkable in multi-pole machines (four poles or more) where the armature winding is inevitably complicated.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing an embodiment of the present invention, and is a diagram showing a cross-sectional view of an iron core portion.

3 is a diagram showing a square wave magnetic field distribution expressed in a Fourier series for the U phase when the armature windings U, V, and W shown in FIG. 4 are expanded in the θ direction; FIG.

[Figure 4] Arrangement of each phase of armature winding and stator excitation current i
It is a diagram showing the directions of ou, iov, and iow.

FIG. 5 is a diagram showing the magnetic field distribution due to the armature winding of concentrated full-pitch winding.

FIG. 6 is a diagram illustrating various embodiments of rotor excitation windings applied when the armature windings U, V, and W are two poles, as developed views.

FIG. 7 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

U...U phase V...V phase W...W phase 1. Iron core 2. Stator slot 3. Rotor core 4. Rotor slot 5. Rotor field winding 6a・Rotor excitation winding 6b・Rotor excitation winding 6C/rotor excitation winding 7. Stator excitation power supply 8. Impedance element 9a/rectifier 9b・Rectifier 9C/rectifier 10・Output end 11・Output end 12・Output end

Claims (1)

[Claims] Claim 1: An armature winding having a concentrated full-pitch winding or a winding style similar to concentrated full-pitch winding is wound around a stator core in a three-phase star connection, and the lead-out end from the armature winding is Impedance elements forming a three-phase star connection are connected, and a stator excitation power source is connected between the neutral point of the impedance element and the neutral point of the armature winding, and the stator excitation power source and the armature winding are connected. A closed circuit is formed by the winding and the impedance element, and the rotor core includes a rotor excitation winding that is magnetically coupled to pole numbers three times and five times the number of poles of the armature winding. After the electromotive force of the rotor excitation winding is converted into direct current, the rotor field winding is provided and has the same number of poles as the armature winding, and the rotor field winding is wound around the rotor core. A brushless synchronous machine characterized by being equipped with a rectifier for converting the electromotive force of an excitation winding into direct current.