WO2011003547A1

WO2011003547A1 - Electrodynamic activating device

Info

Publication number: WO2011003547A1
Application number: PCT/EP2010/003991
Authority: WO
Inventors: Arno Mecklenburg; Jan Magnus Guldbakke; Rainer Schneider; Rainer Michaelsen
Original assignee: Kendrion Magnettechnik Gmbh
Priority date: 2009-07-05
Filing date: 2010-07-05
Publication date: 2011-01-13
Also published as: DE102009031665B4; DE102009031665A1

Abstract

The invention relates to an electrodynamic actuator. An example of the invention relates to an actuator comprising the following: a magnetic circuit (21, 22), an induction coil (31), and a movable short-circuit winding (12) made of metal, the induction coil and the movable short-circuit winding being arranged on the magnetic circuit, wherein the force acting on the short-circuit winding is used to perform mechanical work and the magnetic circuit is designed in such a way that the metal of the short-circuit winding is completely or partially penetrated by a radial magnetic flux during operation.

Description

Electrodynamic actuator

Technical Field The invention relates to the field of electrodynamic actuators for various applications, e.g. the operation of high-voltage switches or as an actuator in solenoid valves.

Technical background

The mode of action of electrodynamic actuators is based on the effect of the Lorentz force. This occurs when a current-carrying conductor is in a magnetic field, wherein the current-carrying conductor is movably mounted relative to the magnetic field. This effect is impressively illustrated by the well-known collaborative effort originally discovered by Elihu Thomson. Furthermore, the reluctance force (Maxwell force) can play a role in electrodynamic actuators.

In the ring trial according to Thomson, a ring of electrically conductive material (eg copper) is arranged around an elongated coil with soft iron core. During a short current pulse through the coil, due to the action of the Lorentz force, the ring jumps off the coil, which is also referred to as the Thomson coil. Thomson coils are not common as actuators because they have low efficiency and poor electromagnetic compatibility due to their large stray field and other losses (eg iron losses). The required for such actuators fast switching of high currents is technically complex, providing a correspondingly high electrical power also. Another type of electrodynamic actuators are voice coils. Voice coils are fast actuators and can operate at frequencies up to several tens of kHz. But it is fragile and complex constructions, because the force is generated at the coil. The use of a robust bobbin reduces the merits of a voice coil as the mass of the robust bobbin needs to be accelerated. An alternative to electrodynamic actuators are electromagnetic actuators such as solenoids. Such actuators are mechanically more stable, but electrically comparatively sluggish, ie slow. The object underlying the invention is to provide an electrodynamic actuator available that combines the advantages of solenoids (robustness) and voice coils (speed) in itself, also low stray fields and, based on its volume, generates a high force.

Summary of the invention

This object is achieved by an actuator according to claim 1. Exemplary embodiments and further developments of the invention are the subject of the dependent claims.

An electrodynamic actuator is disclosed. An example of the invention relates to an actuator comprising: a magnetic circuit, an induction coil, and a movable metal shorting coil disposed on the magnetic circuit, wherein the force acting on the shorting turn is utilized to perform mechanical work and the magnetic circuit is configured that During operation, the metal of the short-circuit winding is completely or partially penetrated by a radial magnetic flux. The magnetic flux should therefore be introduced as well as possible in the radial direction in the plane of the short-circuit winding with respect to the short-circuit winding, so that the highest possible flux density in the radial direction is generated. Brief description of the pictures

The following figures and the further description should help to better understand the invention. Further details, variants and further developments of the inventive concept will be explained with reference to figures which relate to a specific selected example. The elements in the figures are not necessarily to be construed as limiting, rather value is placed to represent the principle of the invention. In the figures, like reference numerals designate corresponding parts.

Fig. 1 is a sectional view of an embodiment of the electrodynamic actuator according to the invention; FIG. 2 is a perspective sectional view of another exemplary embodiment of the electrodynamic actuator according to the invention which is very similar, for example, from FIG. 1; 3 illustrates, by way of example, the radial magnetic field profile in the region of the short-circuit winding of the actuator, and 4 is a perspective sectional view of a further embodiment of the electrodynamic actuator according to the invention with additional coils. Detailed description

In the following, a specific exemplary embodiment will be explained in more detail with reference to the sectional drawing shown in FIG. FIG. 2 is a perspective sectional view of the actuator. FIG. 1 is a cross section through a vertical plane of symmetry of the electrodynamic actuator 1. The actuator 1 comprises at least the following components: a magnetic circuit formed, for example, by a two-part magnetic core (ferromagnetic magnetic core parts 21, 22); an induction coil wound, for example, on a bobbin 31 placed on the magnetic core; and a movable short circuit winding 12 made of metal, which is also arranged on the magnetic circuit, ie, the short-circuit winding is engages around the magnetic core 21, 22 and is movably mounted on this in the axial direction. The force acting on the short-circuit winding 12 can be utilized to perform mechanical work. For this purpose, the magnetic circuit (eg, the magnetic core parts 21, 22) is designed such that during operation the metal of the short-circuit winding 12 is completely or partially penetrated by a radial magnetic flux. The radial direction is thus in the plane of the short-circuit winding 12 and is normal to the circumferential direction (axial direction) of the magnetic circuit 21, 22. The metallic Kurzschlusswindung 12 (eg made of copper or aluminum) can on a ring guide 11 made of plastic (eg PEEK, ie polyetheretherketone) may be arranged. The magnetic circuit may be composed of one, two or more magnetic core parts consist. In the present example, the magnetic circuit is formed by a two-part magnetic core (lower magnetic core part 22, upper magnetic core part 21), wherein the two magnetic core parts 21, 22 are joined together without air gap. Furthermore, in the present example, a plastic cover 40 is provided, which is arranged on the upper magnetic core part 21 and also made of PEEK or another

Plastic can be made. The Kurzschlusswindung 12 may be constructed of laminated, the best possible electrical conductors.

The generation of the magnetic flux passing through the short-circuit winding 12 in the radial direction can be assisted by at least one additional coil (see FIG. 4: coil support 51 above the short-circuit winding 12). These generate a smaller flux than the induction coil (coil support 31 above the short-circuit winding 12), wherein the flooding of the additional coil (s) counteracts the flooding generated by the induction coil. The magnetic flux in the radial direction can be concentrated by means of pole shoes on the stroke range of the movable short-circuit winding.

Instead of one or more additional coils (or as an additional measure), the magnetic flux in the radial direction can also be generated by the magnetic circuit is designed such that the magnetic circuit partially saturates. This can be achieved by a local reduction of the cross section of the magnetic core 21, 22 (see area 60 of the magnetic core part 21 in FIG. 2 or 4), or by using a magnetic material in at least a portion of the magnetic circuit whose saturation polarization is lower than that of the material from which the rest of the magnetic circuit stands. Alternatively or additionally, instead of the additional coils, permanent magnets (eg rare earth magnets) may be used to generate the radial flux. Suitable materials for the magnetic circuit are various ferromagnetic materials, for example soft magnetic materials such as an iron-based, metallic glass, an iron-based nanocrystalline alloy or an iron-cobalt alloy (eg VACOFLUX 18H) which in particular up to 5% other elements ( for example, vanadium and silicon) and has the highest possible electrical resistance.

The pole shoes (see area 61 of the magnetic core part 21 in FIG. 2 or 4) and the magnetic circuit can be made of different materials, the relative permeability of the material of the pole shoes being lower than that of the material of the rest of the magnetic circuit. However, the saturation polarization of the material of the pole shoes should be higher than that of the material of the rest of the magnetic circuit. In a specific embodiment, the materials of the magnetic circuit and the pole shoes are each laminated, wherein the planes of the respective lamination are perpendicular to each other. In particular, magnetically semi-rigid materials can be used for the pole pieces.

Instead of an induction coil, it is also possible to arrange two (see FIG. 1 with two induction coils on the two bobbins 31) or another even number of coils on the magnetic circuit, all coils (including the additional coils mentioned above) being arranged in such a way that that a multipole stray field as short as possible (in the far field, the magnetic field falls proportionally to l / r ³ or stronger, where r is the Distance to the magnet) range is generated as soon as the magnetic circuit (or a portion thereof) saturates.

In another embodiment, the electro-dynamic actuator is equipped with a return spring (not shown), i. the Kurzschlusswindung 12 is pressed or pulled by means of a spring in a rest position. A particularly compact design results when the return spring between the magnetic circuit (magnetic core 21, 22) and the short-circuit winding 12 acts. Alternatively, the return spring may also be arranged such that the restoring force acts between the electrodynamic actuator and the mechanism to be actuated. The spring may have a non-linear spring characteristic and modulate a force generated by the actuator so that it is matched to the requirements of the mechanism to be actuated, i. the force-displacement characteristic of the actuator can be selectively influenced by the spring. As a nonlinear spring, e.g. a leaf spring or a plate spring into consideration or a package of leaf springs or disc springs.

The energy necessary to operate the actuator may e.g. stored in a capacitor. The energy for operating the actuator can be stored in the capacitances of a delay line whose impedance is matched to that of the electrodynamic actuator and which is charged directly or via a storage inductance.

According to one exemplary embodiment, a capacitor with the aid of a pulse width modulator is discharged via the induction coil (s) of the electrodynamic actuator, so that many electrical switching operations take place during a single mechanical setting process; the pulse width modulation is applied to the pulse width modulator Tuned requirements of the mechanism to be actuated, ie by a pulse width modulation, the time course of the coil current can be adjusted by the induction coil and thus the behavior of the actuator can be influenced.

Between capacitor and actuator is a magnetic pulse compression (delay chain with saturable reactors, which provides the load side extremely steep-flanked current pulses and the memory side protects the / the switch), whose impedance is matched to that of the electrodynamic actuator.

As an alternative to the capacitor is also an inductive energy storage into consideration, which is adapted to the impedance of the electrodynamic actuator. With impedance matching, the power transferred between the power supply and the actuator is maximum. For optimum efficiency, the internal resistance of the power supply of the actuator should be as minimal as possible. Between the inductive storage and the electrodynamic actuator, an impedance converter may be connected.

The electrodynamic actuator can be so combined with a solenoid so that a holding force is generated. The movable short-circuit winding 12 is rigidly connected to a movably mounted part of the magnetic circuit 21, 22. The magnetic circuit 21, 22 has in the initial state a taper of the cross section, which is reduced or destroyed by movement of the movably mounted part of the magnetic circuit in the direction in which the Lorentz force acts on the KurzSchlusswindung 12. In this case, the generated force is exerted on the movably mounted part of the magnetic circuit to the actuated by the actuator mechanism. In other words, a part of the magnetic circuit is connected to the short circuit and moves together with the short-circuit winding. The magnetic circuit is designed so that during movement the cross section of the magnetic circuit becomes larger (ie the taper is reduced), which results in a corresponding reluctance force. In this way, the effect of the force acting on the short-circuit winding by the action of an additional reluctance force (such acts even with a solenoid) on the movable part of the magnetic core is amplified. In this way, a holding force can be generated by utilizing the DC component through the induction coil.

Depending on the application, the short-circuit winding 12 can be reinforced mechanically with the aid of a correspondingly shaped component

(e.g., by the ring guide 11), which is made of a harder material than the short circuit winding 12. The force can e.g. be transferred by means of a rod arranged in the axial direction of the actuated mechanism.

The electrodynamic actuator can be arranged in a housing, which consists for example of Mu metal or a comparable soft magnetic material. The mode of operation of the electrodynamic actuator from FIGS. 1 or 2 will be clarified again below with reference to the course of the magnetic field lines shown schematically in FIG. 3. The feeding of a current into the induction coil (coil carrier 31) results in a corresponding magnetic field 51, which in turn - according to the law of induction - results in a corresponding short-circuit current in the course winding 12. This short-circuit current in turn generates a magnetic field 52, which - according to the Lenz's rule - the magnetic field of the induction coil is opposite. Consequently, apart from stray fields, the magnetic fields 51 and 51 of the induction coil and the short-circuit winding are destructively destructed in the axial direction, so that in the region of the short-circuit winding, the axial magnetic field

Flux density B _{AX is} very small, ideally zero. The radial components of the magnetic fields 51 and 52 overlap constructively, which in the region of the short-circuit winding results in a very strong radial magnetic flux density B _R. This radial magnetic flux density B _R in the region of the short-circuit winding results in an axial Lorentz force which acts on the short-circuit winding 12 and which is available as an actuator force. The approximate extinction of the magnetic field in the axial direction, which is necessary for the functioning of the actuator, and the associated concentration of the magnetic flux density in the radial direction in the region of the short-circuit winding is achieved with the aid of the closed magnetic circuit and is the better, the better the electric Conductivity of the Kurzschlusswindung 12 and the lower the iron losses are around magnetic circuit.

Claims

Claims:

An electrodynamic actuator comprising:

an induction coil,

a movable metal short-circuit winding, and a magnetic circuit on which the induction coil and the short-circuit winding are arranged,

wherein the force acting on the short-circuit winding is utilized for performing mechanical work, and

wherein the magnetic circuit is configured such that during operation, the metal of the short-circuit winding is completely or partially penetrated by a radial magnetic flux.

2. Device according to claim 1, characterized in that the generation of the radial flow is realized by at least one additional coil, which generates a smaller flux than the induction coil (s) whose flow (s) it counteracts / s, and that the radial flow is concentrated by means of pole pieces on the stroke range of the movable short-circuit winding.

3. A device according to claim 2, characterized in that instead of one or more additional coils, the radial flux is generated by the magnetic circuit is designed such that it partially saturates during operation, resulting in a local reduction of the cross section or the use of a magnetic material can be achieved in the magnetic circuit whose saturation polarization is less than that of the material from which the rest of the magnetic circuit consists.

4. Apparatus according to claim 2, characterized in that instead of one or more additional coils permanent magnets, preferably rare earth magnets, may be used to generate the radial flux (thereby easily enabling electrical resetting).

5. The device according to claim 1, characterized in that a soft-magnetic material for the magnetic circuit, an iron-based metallic glass or an iron-based nanocrystalline alloy is used.

6. Apparatus according to claim 1, characterized in that as soft magnetic material for the magnetic circuit, an iron-cobalt alloy is used.

7. The device according to claim 6, characterized in that the iron-cobalt alloy contains up to 5% of other elements, in particular V or Si, and has the highest possible specific electrical resistance.

8. Devices according to claim 2 or 3 or 4 characterized in that the pole shoes and magnetic circuit of different

Materials exist and that the relative permeability of the Polschuhwerkstoffes is lower than that of the magnetic circuit material and that its saturation polarization is higher than that of the magnetic circuit material.

9. Apparatus according to claim 8, characterized in that magnetic circuit and Polschuhwerkstoff are laminated and that their lamination levels are perpendicular to each other.

10. The device according to claim 9, characterized in that a magnetically semi-hard material is used for the pole pieces.

11. The device according to claim 1, characterized in that the electrodynamic actuator is combined with a lifting magnet such that a holding force can be generated.

12. The device according to claim 11, characterized in that the movable short circuit winding is rigidly connected to a movably mounted part of the magnetic circuit and that the magnetic circuit in the initial state has a taper of the cross section, which by movement of the movably stored part of the magnetic circuit in that direction, in which the Lorenz force acts on the Kurzschlusswindung, is reduced or destroyed. The generated force is exerted on the movably mounted part of the magnetic circuit on the mechanism to be actuated by the actuator.

13. The device according to claim 1, characterized in that the electrodynamic actuator is equipped with a return spring.

14. The apparatus according to claim 13, characterized in that the return spring acts in the electrodynamic actuator between short-circuit winding and magnetic circuit (which allows a particularly compact design).

15. The apparatus according to claim 13, characterized in that the return spring acts between the electrodynamic actuator and the mechanism to be actuated.

16. The apparatus of claim 14 or 15 characterized by the fact that the spring has a non-linear characteristic and modulates the impulse generated by the electrodynamic actuator such that it is tuned with the requirements of the actuated mechanism.

17. The apparatus according to claim 16, characterized in that a plate or leaf spring package is used as a non-linear spring.

18. Device according to claim 1, characterized in that the electrical energy required to operate the electrodynamic actuator is stored in a capacitor.

19. The device according to claim 1, characterized in that the required for the operation of the electrodynamic actuator electrical energy is stored inductively.

20. The device according to claim 1, characterized in that the electrical energy required for the operation of the electrodynamic actuator is stored in the capacitances of a delay line whose impedance is matched to that of the electrodynamic actuator and which is charged directly or with a storage inductance.

21. The device according to claim 18, characterized in that the capacitor is discharged by means of a pulse width modulator, which is advantageously realized with MOSFETs, via the electrodynamic actuator, so that many electrical switching operations occur during a single mechanical positioning process.

22. The device according to claim 21, characterized in that the pulse width modulation is matched with the requirements of the mechanism to be actuated.

23. The device according to claim 18, characterized in that between the capacitor and the actuator, a magnetic pulse compression is connected (runtime chain with saturable reactors, which provides the load side extremely steep edge current pulses and memory side protects the / the switch), whose impedance is matched to that of the electrodynamic actuator.

24. The device according to claim 19, characterized in that the impedance of the inductive memory is tuned to the impedance of the actuator.

25. The device according to claim 19, characterized in that an impedance converter is connected between the inductive storage and the actuator.

26. The device according to claim 1, characterized in that instead of a single induction coil, an even number of induction coils is used, all coils (including additional coils according to claim 2) are arranged such that, as soon as the core saturates a multipole stray field as short as possible Range arises.

27. The device according to claim 1, characterized in that the electrodynamic actuator is housed with Mu metal or a comparable soft magnetic material.

28. The device according to claim 1, characterized in that for the short-circuit winding laminated as good as possible electrical conductors are used.

29. The device according to claim 1, characterized in that the force is transmitted by means of an axially disposed rod from the short-circuit winding on the mechanism to be actuated, wherein the short-circuit winding expediently by a building part can be strengthened mechanically, which consists of a harder material than the short circuit winding.