WO2000031858A1

WO2000031858A1 - Electromagnetic axial machine

Info

Publication number: WO2000031858A1
Application number: PCT/EP1999/009150
Authority: WO
Inventors: Werner Schüssler; Michael Müller
Original assignee: Schuessler Werner; Mueller Michael
Priority date: 1998-11-25
Filing date: 1999-11-25
Publication date: 2000-06-02

Abstract

The invention relates to an electromagnetic axial machine. Said machine is provided with a rotating shaft (2; 102), an induction element (4; 104) with at least two parallel windings (5, 7; 105, 107) and an exciter element (9; 109) which is arranged at a first end of the induction element (4; 104) and at an axial distance thereto. Said exciter element has at least two magnets (10, 11; 110, 112a; 111, 112b) which are linked to the exciter element via a magnetizable yoke (12; 112). One of the two elements (4, 9; 104, 109) is mounted to the shaft (2; 102), the other one is stationary. The machine is further provided with a magnetizable return element (13; 113) which is arranged at a second end of the induction element (4; 104) and at an axial distance thereto. The exciter element (9; 109) and the return element (13; 113) are fixed relative to one another.

Description

Electromagnetic axial machine

The invention relates to an electromagnetic axial machine.

Electromagnetic machines, that is to say generators or motors, can be designed as an axial machine or as the radial machine that is found much more frequently. Both types have an induction part and an excitation part, one of the two parts being attached to a shaft, while the other part is static, so that there is a relative movement between the two parts.

In the case of a radial machine, the movable part is fastened to the shaft and the stationary part surrounds the movable part along the circumferential surface.

In an axial machine, the induction part and the excitation part are axially spaced apart. One of the two parts is attached to the shaft, while the other stationary part is arranged at an axial end of the first part.

The induction part is the part in which in generator operation, i.e. when mechanical to electrical energy is converted, an induction voltage is generated. For this purpose, the induction part contains windings, at the ends of which the induction voltage can be tapped. In engine operation, i.e. when electrical to mechanical energy is converted, a voltage is applied to the induction member so that the induction member generates a magnetic field.

The excitation part is magnetic. Excitation part and induction part are relative to each other when the machine is operating emotional. In generator operation, the magnetic field predetermined by the excitation part induces a voltage in the induction part, since there is a temporally changing magnetic flux due to the relative movement. In motor operation, the excitation part specifies a magnetic field due to the applied voltage, which leads to a relative movement between the two parts due to the magnetic forces acting between the induction part and the excitation part.

Electromagnetic machines have a back yoke part, which has the purpose of closing the magnetic circuit if the exciter and induction part are covered. The magnetic flux is then guided through the excitation part through the cores made of a soft metal, which are usually located in the coils, and through the return part. In the case of radial machines, the induction part and the yoke part are fixedly arranged, while the excitation part rotates with the shaft of the axial machine. This has proven to be disadvantageous in generator operation, since the magnetic flux predetermined by the rotating exciter part changes in time at the yoke part, which leads to hysteresis losses, since the yoke part is reversed magnetically with each revolution.

The invention has for its object to provide an axial machine with improved efficiency.

This object is achieved with the features of claim 1.

The invention proposes to firmly arrange the excitation part and the yoke part at opposite ends of the induction part and at an axial distance from it and from one another, so that when the excitation part rotates with the shaft, the yoke part is also fastened to the rotating shaft, or that the excitation part and that Yoke part sta- are functional if the induction part rctures with the shaft. This has the result that the magnetic flux flowing through the return part is unchanged in time, since the magnetic field is applied in generator operation by the exciter part which is relatively moved to the return part. Thus there are no temporal changes in the magnetic flux in the yoke part, which would bring about a magnetic reversal. The resulting hysteresis losses are thus avoided, which increases the efficiency of the axial machine. However, the soft iron parts in the induction part have to be magnetized.

In a preferred embodiment of the invention, the excitation is divided, specifically in such a way that an excitation source, such as a magnet, is present on the spring-changing area of coverage. Variable areas of overlap are the transitions between the magnets of the excitation part and the coil cores of the induction part and the transitions between the magnets of the yoke part and the coil cores of the induction part Generatcroetneo one in Vergieicn z. the undivided excitation was more than twice as powerful. It has also been shown that the effect of the distributed excitation can also be achieved without magnets connected via a yoke, albeit with losses in the power generated. Instead of the yoke and the two magnets, a solid magnetizable metal part can also be used, which is magnetized by the excitation part in a start-up phase, so that after the start-up phase it acts like a large magnet itself.

The material of the back part can be made solid, since αer

The flow in the return part does not change in time and therefore no eddy current losses occur. to step. A solid yoke part has the advantage that there is more magnetic material per volume and thus the efficiency of the machine increases. In addition, massive inference parts are cheaper.

Advantageously, the excitation part and the yoke part rotate with the shaft while the induction part is stationary. In the case of an excitation part and a yoke part with permanent magnets, contacting the two parts with a brush and a slip ring is then not necessary in order to supply an excitation voltage. The tapping of the induced voltage at the inductive part is not problematic since this part is stationary.

If the excitation part has electromagnets, the coil cores of the coil can be made long so that many windings can be applied to the coil core, which has the advantage that, due to the large number of windings, only a small excitation current is required, so that only a small brush fire arises on the slip ring. However, this increases the flywheel mass of the exciter part, so that there is only a small brush fire on the commutator.

Alternatively, it is possible to briefly form the coil cores, which reduces the flywheel mass, but also reduces the number of windings and thus leads to a larger brush fire in this exemplary embodiment.

An alternative version of the invention is an electromagnetic axial machine with the features of claim 6. In this, the induction part and the excitation part are stationary, while only the yoke part rotates. This has the advantage that the windings of the induction part and the excitation part do not require slip rings because there are no movable coils. By dispensing with moving coils, the moving mass is also small. hold so that the machine has a low moment of inertia.

Large machines with high power have the main problem in cooling the coils, which is usually done with hydrogen. Such fluid cooling is facilitated by the exclusive use of stationary coils. In addition, the machine can be more easily brought into the superconducting state.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings:

Show it:

1 is a perspective view of a first embodiment of the axial machine,

2 shows a schematic diagram of the first exemplary embodiment,

3 is a schematic diagram of a second embodiment,

4 shows a schematic diagram of a further exemplary embodiment,

Fig. 5 is a schematic section along the line V-V of Fig. 4, and

6 is a side view of the yoke part in the embodiment of FIG. 4th

1 shows the basic structure of the electromagnetic axial machine 1 according to the invention. The axial machine 1 has a shaft 2 which is connected to a shaft (not shown) mechanical power source is connected, which rotates the shaft 2 in generator operation of the axial machine 1. The following statements are made with regard to the generator operation of the axial machine 1. Of course, the axial machine can also be used in motor operation.

On a base plate 3, which carries the entire device, an induction part 4 is arranged in a stationary manner. The induction part 4 has a first coil 5 with a coil core 6 made of soft metal. A second coil 7 of the induction part 4, which surrounds an iron core 8, is arranged symmetrically to the shaft 2. The coil cores 6, 8 are arranged parallel to the shaft 2. The two coils 5, 7 are connected in series. Several coils can also be arranged distributed over the circumference.

At a first axial end of the induction part 4 and at an axial distance from it, an excitation part 9 is arranged, which is attached to the shaft 2 and rotates with it. The excitation part 9 contains two permanent magnets 10, 11 which are connected to one another via a metallic magnetizable yoke 12. The length of the yoke 12 specifies the radial distance of the permanent magnets 10, 11 from the shaft 2. This distance is dimensioned such that the permanent magnets 10, 11 completely cover the coil cores 6.8 m in a certain state, the so-called overlapping state, which is shown here in FIG. 1.

At the second axial end of the induction part 4, a yoke part 13 is arranged and fixed to the shaft 2 so that it rotates together with the latter and the excitation part 9. The yoke part 13 has an identical structure to the exciter part 9. It has two permanent magnets 14, 15 and a yoke 16 connecting them. The exciter part 9 and the yoke part 13 are attached to the shaft 2 in the same orientation, ie both cover the same time Coil cores 6, 8 of the induction part 4. The four permanent magnets 10, 11, 14, 15 are arranged with alternating polarity (FIG. 2), so that in the overlapping state, a continuous magnetic flux through the coil cores 6, 8, the permanent magnets 10, 11, 14.15 and the yokes 12.16 flows.

In generator operation of the axial machine 1, the shaft 2 is rotated by an energy source, not shown, so that the excitation part 9 and the yoke part 13 rotate. Since the rotating permanent magnets 10, 11, 14, 15 generate the magnetic field, the magnetic flux in the stationary coil cores 6, 8 changes over time. This change in flow induces a voltage in the windings 5, 7 of the induction part 4. This induced voltage can be tapped off via terminals and fed to an electrical consumer.

Since the magnetic flux in the coil cores 6,8 changes over time, they are built up from generator sheets, i.e. made of thin metal sheets insulated from each other so that eddy current losses are avoided. Since the magnetic flux in the yokes 12, 16 is not subject to changes in time, the yokes are made of solid material.

The distribution of the excitation to the four permanent magnets 10, 11, 14, 15 causes a particularly rapid change in flux when the degree of coverage changes, which leads to a high induced voltage, since the induced voltage corresponds to the change in magnetic flux over time times the number of turns of the induction coils .

3 shows an axial machine 101 according to a second exemplary embodiment. This axial machine 101 also has a shaft 102, an induction part 104 with a first coil 105, which is wound around a coil core 106, and a second opposite coil 107, which is wound on a coil core 108. The excitation part 109 consists of a U-shaped. Yoke 112, on the first leg 112a of which a first field winding 110 is wound. A second excitation winding 111 is applied to the second yoke leg 112b. A yoke part 113 has a first leg 114 and a second leg 115 for covering the two coil cores 106, 108, the two legs 114, 115 being connected to a yoke 116.

In contrast to the first exemplary embodiment, the induction part 104 is fastened to the shaft 102 in this axial machine 101 and rotates with the latter. For this purpose, the two coils 105, 107 connected in series are fastened to the shaft 102 with lateral holding elements 117. The holding elements 117 have cutouts in order to allow the coil cores 106, 108 to protrude, so that there is only a small air gap between the coil cores 106, 108 and the legs 112a, 112b, 114, 115. The induction part 104 has radially outer and circumferential slip rings 118, against which brushes 119 rest for tapping off the induced voltage.

In generator operation of the axial machine 101, the shaft 102 is driven by an engine, not shown, and an excitation voltage is applied to the excitation windings 110 and 111. These coils generate a magnetic flux in the yoke 112, which is magnetized thereby. When the induction part 104 is in the overlapping state, a magnetic flux flows through the coil cores 106, 108 and the yoke parts 112, 116, whereby a voltage is induced in the coils 105, 107. Since the magnetic flux in the yoke part 113 is always rectified, there are no hysteresis losses which reduce the efficiency. After a start-up phase, the efficiency is increased even further, since the yoke part 113 has a time is flowed through unchanged magnetic flux, which leads to it being completely magnetized and then contributing to the excitation of the induction part 104 like a magnet.

Features of the two exemplary embodiments can be combined with one another. For example, in the embodiment of FIGS. 1 and 2, the permanent magnets 10, 11 and possibly also the permanent magnets 14, 15 are replaced by electromagnets as shown in FIG. 3 (110, 112a; 111,, 112b).

In Figures 4 to 6 is a. Another embodiment shown, in which all coils are arranged stationary and only the yoke part rotates. The induction part 204 consists of a plurality of circumferentially distributed parallel coil cores 206, 208, which are aligned parallel to the shaft 202, and windings 205, 207, each of which surround a coil core. The induction part 209 has a sleeve 211 which carries the excitation winding 210. A shaft part 212 passes through the sleeve 211 and forms the coil core of the winding 210 and is firmly connected to the shaft 202. The shaft part 212 can thus rotate in the sleeve 211.

The yoke part 213 consists of yoke parts 214, 215 and 216, 217, which each protrude from opposite sides of the yoke part 212 forming the coil core of the excitation winding 210 and paint over the ends of the induction part 204. The induction part 213 rotates together with the shaft 202.

This machine can also be operated either as a motor or as a generator.

FIGS. 5 and 6 show the cross-sectional sizes of the winding cores 206 and 208, as well as the transverse Section size of the winding core 212. The cross section of the core 212 of the excitation part is as large as the sum of the cross sections of all the winding cores 206, 208 of the induction part.

The area of a yoke part 216, 217 is as large as the cross-sectional area of a winding core 206, 208 of the induction part 204. The area of the shaft part 212 of the yoke part 213 is as large as the cross-sectional area of the winding core 212 of the excitation part 209.

In the exemplary embodiment in FIGS. 4 to 6, the induction part 204 has a total of 4 windings 205, 207, while the yoke part 213 has two yoke parts 214, 215 and 216, 217 at each end. It may be appropriate to increase the number of induction windings. So instead of four, eight induction windings could be used. In this case, the number of yoke parts of the yoke part would also be expediently increased.

Claims

EXPECTATIONS

1. Electromagnetic axial machine, with a rotating shaft (2; 102), an induction part (4; 104) with at least two windings (5, 7; 105, 107) arranged in parallel, one at a first end of the induction part (4; 104) and at an axial distance from this excitation part (9; 109) with at least two magnets (10, 11; 110, 112a; 111, 112b) connected via a magnetizable yoke (12; 112), one of the two parts (4, 9 ; 10, 109) attached to the shaft (2; 102) and the other is stationary, and one at the second end of the induction part (4; 104) and at an axial distance from this arranged magnetizable return part (13; 113), the Excitation part (9; 109) and the yoke part (13; 113) are fixed relative to each other.

2. Electromagnetic axial machine according to claim 1, characterized in that for the distribution of the excitation, the yoke part (13) has two magnets (14, 15) connected via a yoke (16).

3. Electromagnetic axial machine according to claim 1 or 2, characterized in that the yoke part

(13; 113) is massive.

4. Electromagnetic axial machine according to one of claims 1-3, characterized in that the magnets (10, 11; 14, 15) are permanent magnets.

5. Electromagnetic axial machine according to one of claims 1-4, characterized in that the excitation part (9) and the yoke part (13) rotate with the shaft (2).

6. Electromagnetic axial machine, with a rotating shaft (202), a stationary induction part (204) with at least two windings arranged in parallel

(205, 207), a stationary excitation part (209) with at least one excitation winding (210) and a magnetizable yoke part (213) rotating with the shaft (202), the yoke parts (214, 215; 216, sweeping over the ends of the induction part (204), 217) which protrude from a shaft part (212) passing through the excitation winding (210).

7. Electromagnetic axial machine according to claim 6, characterized in that the excitation part (209) has a winding core (212), the cross section of which is approximately equal to the sum of the cross sections of the winding cores (206, 208) of the induction part (204).

8. Electromagnetic axial machine according to claim 6 or 7, characterized in that the number of windings (205, 207) of the induction part (204) is twice as large as the number of yoke parts (214, 215) of the yoke part (213).