WO2011012111A9

WO2011012111A9 - Method for operating a magnetic actuator

Info

Publication number: WO2011012111A9
Application number: PCT/DE2010/000857
Authority: WO
Inventors: Jürgen MAAS; Dirk GÜTH; Martin Aust; Christian Graf
Original assignee: Hochschule Ostwestfalen-Lippe
Priority date: 2009-07-27
Filing date: 2010-07-22
Publication date: 2011-05-12
Also published as: WO2011012111A3; WO2011012111A2; DE112010003090A5

Abstract

The invention relates to a method for operating a magnetic actuator (1) for the transmission and/or generation of torques, said actuator comprising a driving shaft (2) and a driven shaft (3) onto which field-induced forces of a magnetorheological medium act in at least one gap (18, 20) between the driving shaft (2) and the driven shaft (3). An m-phase rotary field (B) is applied to at least one field generator (13), said rotary field having a controllable current (i₀, i_Sd, i_Sq).

Description

Method for Operating a Magnetic Actuator Description:

The invention relates to the operation of a magnetic actuator for transmitting and / or generating torques, comprising a drive shaft and an output shaft, to which the field-excited forces of a magnetorheological medium act in at least one gap.

Magnetorheological fluids, often abbreviated MRF, are

Liquids comparable to ferrofluids on a

Magnetic field react, but in contrast to this solidify. Magnetorheological fluids are suspensions of micron-order magnetic particles that form chains under an applied magnetic field. This increases the apparent viscosity of the magnetorheological fluids up to solidification.

These physical properties of the magnetorheological fluids make it possible, in particular to transmit torques via applied magnetic fields as it were adjustable, as is known, for example, from US Pat. No. 7,240,485 B2.

However, those on the magnetorheological fluids

acting compressive forces too large, break the chains formed in a magnetic field, so that the transferable

Forces are limited.

DE 10 2009 011096.8 proposes a magnetic actuator for a transmission of torques, in which comparatively large torques can be transmitted via a gap filled with a magnetorheological medium under the action of magnetic field forces

CONFIRMATION COPY advantageously designed slip-ring also the

Generation of torques can serve and beyond that is designed mechanically simple.

In the magnetic actuator explained there, it is provided that the drive shaft ends in a housing in a flange, that on the flange at least one cylinder

is arranged and that the cylinder coaxially engages over the output shaft forming a gap filled with the magnetorheological medium gap.

This actuator can be advantageously as a motor for torque generation by applying electrical

Use fields, but also as torque-resistant

Generator, so that used here consistently

Designating the input and output shafts with respect to their function according to the selected operating mode.

If a rotating field is applied to a field generator of such an actuator, it can be achieved that a torque can be provided both on the drive shaft and on the output shaft.

For generating an electromagnetic to be applied

Feldes is further provided that through the housing a pointing into the housing interior, of the drive shaft

penetrated core is formed, which in further,

constructive design carries a radially inner field generator. These measures allow the

schleifringlose training of the device, as the

Field generator can be easily connected electrically through the housing of the device. Is there a radially inner and a likewise fixed to the housing, radially outside field generator provided and is also between the outer field generator and a radially outer cylinder of the rotor

Drive shaft with the magnetorheological medium

filled gap provided so radially inner columns, for example, for coupling purposes and outer columns for braking with appropriate application of magnetic fields can be used.

In particular, for the operation of such, from DE 10 2009 011 096.8 known magnetic actuators for transmission and / or generation of torques, comprising a

Drive shaft and an output shaft to which the

field-excited forces of a magnetorheological medium acting in at least one gap between the drive shaft and the output shaft is provided according to claim 1 of the invention that at least one field generator m-phase rotating field is applied and that the rotating field has a controllable current, eg. such that the rotating field is superimposed on the field of a controllable current.

This measure allows the magnetic actuators in question in a wide variety of functional variants

operate, in particular having the functions brake and clutch, brake and electric motor torque generator, clutch and electric motor torque generator and brake, clutch and electric motor torque generator, each of which the individual functions can be controlled separately. This applies in particular if a radially inner and a radially outer lying

Field generators are provided. As a result of the displacement of the m-phase rotating field by the controllable current, the columns filled with a magnetorheological medium can be targeted in their physical transfer behavior controlled and thus the functions are switched as it were.

This controllable current can be constant, in particular have a DC component, but this need not. It may also be an alternating current of arbitrary frequency and waveform, which may therefore be time-dependent and / or a component dependent on the position of the drive shaft to the output shaft and / or of a load,

optionally also imprinted in addition to the DC component.

There are two possibilities for impressing the controllable current. It can be provided that the m-phases of the rotating field of the controllable current is impressed directly, for example, when these m-phases are connected together in a star connection and the controllable current is switched to this star point.

Alternatively or additionally, it can be provided that at least one separately formed winding of a field generator is acted upon by the controllable current. In this case, although an additional winding is accepted, but by this measure the rotating field and the controllable current can be kept completely independent of each other and is the influence of the controllable current on the overall system

magnetic actuator immediately recognizable or controllable.

It will then expediently be provided that a separately formed winding has 2m winding packages and that the winding packages are spatially arranged directly following one another and connected in opposite directions in series and / or in parallel. Regardless of the spatial configuration, radially wound winding packages or axially wound winding packages, this measure ensures that with

Magnetorheological media filled columns over its axial length uniformly influenced by a radially also largely largely over the axial length constant, magnetic field of the controllable current.

The same is achieved if it is provided that are acted upon by the rotating field 2m winding packets and that the winding packets are spatially connected in each case in an arrangement n-th winding package with (n + m) -tem winding packet in series and / or in parallel. If the winding packages are arranged radially, they are acted upon successively with the first to the last and then again with the first to the last phase. Are they extending?

Winding packages axially, are in phase applied winding packages diametrically opposite in a cross section.

In particular radially extending winding packages are controlled by a drive circuit such that a static field is generated, for example, that of

controllable current. In this case, the drive circuit may be formed as a 1-Q controller or as a 2-Q controller or as a 4-Q controller, by which in a diagram of the voltage applied to the winding package over the voltage in the

Winding packet flowing current of the mathematically first, the first and the third as well as all four quadrants can be put.

It is also preferred that axially extending

Winding packets from a drive circuit such

be controlled so that a rotating field is generated. Such is comparable to conventional electric motors and it can be further provided that the drive circuit as a Pulse inverter with branches or as one

Pulse inverter with m + 1 branches or by m H-bridges or as a matrix converter is formed. In a pulse inverter with m branches then each of the m winding packages is applied, which are connected together to form a central star. If a pulse inverter with m + 1 branches is used, the central star is connected to the m + branch.

In contrast to a pulse inverter with only m branches, in a pulse inverter with m + 1 branches, the operation of the magnetic actuator and the controllable current can be impressed directly. This is also possible with the m H bridges and with a matrix converter.

Regardless of the execution of the actuator can continue

provided that the magnetic flux generated by fields by a magnetic hysteresis exhibiting and / or by a magnetic and / or by a magnetically anisotropic material receives a preferred direction, for example, a core of a field generator from a hysteresis

consist ferromagnetic alloy, whereby a holding torque can also be generated without applied electric field, de-energized.

Even anisotropic magnetic materials or magnetic materials themselves can be suitably used and arranged to conduct the magnetic flux in a preferential direction, whereby the usable amount of magnetic flux density is increased with the same energy supply to the field generator.

The invention will be explained in more detail with reference to the drawing, in which only exemplary embodiments are shown schematically. In the drawing shows: 1: serving as a clutch actuator and actuator with a radially inner field generator in an axial longitudinal section,

2 shows an actuator serving as coupling and drive with a radially outer field generator in an axial longitudinal section, FIG. 3 shows an actuator with two field generators serving as clutch and drive, FIG.

4 shows a serving as a clutch and brake actuator with two field generators,

5 shows a serving as a brake actuator and actuator with two field generators,

Fig. 6: the parallel connection of an internal

Field producer,

Fig. 7: a parallel circuit of an outside

Feldzeugers, Fig. 8: a series connection of an internal

Field producer,

Fig. 9: a series connection of an outside

Field producer,

10 shows a first radial section through a

Field generator with axial windings,

11 shows the feeding of the winding packages according to FIG. 10 with a rotating field and a controllable current, FIG. Fig. 12: a radial section through axially arranged

Winding packages with separate winding packages for the controllable current,

13: the interconnection of the winding packages according to FIG

12

14 shows a 1-Q actuator,

Fig. 15: a representation of the in the circuit diagrams

simplified reproduced switch,

16: a 2-Q controller,

17 shows a 4-Q actuator,

18: a pulse inverter with m branches, FIG. 19: a pulse inverter with m + 1 branch,

FIG. 20: a drive circuit having m H bridges, FIG.

21: a matrix converter,

Fig. 22: a model of the control of an asynchronous machine and

Fig. 23: a control of a clutch-motor combination.

Fig. 1 shows in an axial longitudinal section an actuator 1, which serves to transmit a torque from a drive shaft 2 to an output shaft 3 and also generate a torque, thus can fulfill the functions "clutch" and "drive". The drive shaft 2 is made in a housing 4 For example, aluminum rotatably trapped in only indicated bearings 5, 6 and forms within the housing 4 a

Flange 7 of a rotor 8 off. On this flange 7 is a cylinder 9 made of a steel, optionally from a

Anisotropic material, put on, which engages over the output shaft 3.

Also, the output shaft 3 is rotatably trapped in an opening in the housing 4 in two indicated bearings 10,11. In this case, the output shaft 3 passes through a formed by the housing 4 core 12, the radially outward one

Field producer 13 carries. Inside the case, coaxial

within the cylinder 9 of the rotor 8 of the drive shaft 2, a flange 14 is formed from the output shaft 3, for example, an aluminum, the one

Cylinder 15 also made of a steel, if necessary. from another anisotropic material, wears.

The rotor 16 of the output shaft 3 is at the opposite end of the flange 14 of the cylinder 15 with respect to the

Cylinder 9 of the rotor 8 of the drive shaft 2 is sealed, whereby a remaining gap between the cylinders 9,15 18 is completed with a seal 19.

The gap 18 between the cylinders 9,15 as well as the space 20 between the flanges 7,15 is with a

filled magnetorheological medium, preferably one

Carbonyl iron powder of a particle diameter of a few microns in an oil-based carrier liquid.

This changes the flow resistance of the magnetorheological medium and thus an adjustable torque transmission between the drive shaft 2 and the output shaft 3

enabling magnetic field, indicated by B, is generated by the housing fixed field generator 13, the on the solidly executed or laminated core 12 is arranged. By this structural measure can on the use of slip rings for a power supply of the

Field producer 13 will be omitted. This will be the

Function "coupling" allows.

In the magnetic actuator 1 shown in FIG. 1, the magnetorheological medium is located exclusively in the gap 18 and the space 20. Between the inner field generator 13 and the cylinder 15 of the rotor 16 of the output shaft 3 remains an air gap 21 as well as between the housing inner side 22 and the cylinder 9 of the rotor 8 of the drive shaft 2, an air gap 23 remains. In addition to the controllable torque transmission, the actuator 1 can be used for torque generation in the manner of an electric motor the clutch function is maintained

Drive-side torque boosted on the output side

be passed on. Conversely, it is through a

generator operation of the field generator 13 possible to generate a braking torque.

Fig. 2 shows another embodiment of an actuator 25 with a 'radially outer, fixed housing Felderzeuger 26. By seals 27,28 is one with a

magnetorheological medium filled annular gap 29 between a cylinder 30 on a drive shaft 31 and a coaxially arranged cylinder 32 on an output shaft 33 axially completed. Even if the direction of the magnetic

B-field has radially inward, this embodiment of an actuator 25 can be used for the functions "clutch" and "drive", as between the field generator 26 and the Cylinder 32 of the output shaft 33 of the necessary air gap 34 remains.

In the embodiment of an actuator 35 according to FIG. 3 for the functions "clutch" and "drive", the effectiveness of the torque transmission or the torque generation is increased by two field generators, a first, radially inner and fixed housing Feldzeuger 36 and a

second, radially outer and fixed to the housing

Field generator 37. Between the outer field generator 37 and a radially outer cylinder 38 of the rotor 39 of a drive shaft 40 remains a free air gap 41. With the same orientation of the magnetic fields B of the inner field generator 36 and the outer field generator 37, the magnetically active field on the one

magnetorheological medium filled gap 42 between the cylinder 38 and the cylinder 43 of a rotor 44 a

Output shaft 45 significantly increased, which means an increase in the transmittable torque. It can be the

However, magnetic fields B also be directed opposite and so the effect in particular on the with the

magnetorheological medium filled gap 42 at least partially cancel each other. In order to satisfy the functions "braking" and "clutch", 46 are acc. Fig. 4 two with a

Magnetorheologisehen medium filled gaps 47,48 are provided, of which the radially outer gap 47 between an outer field generator 49 and a cylinder 50 of a rotor 51 of a drive shaft 52 is arranged and which is designed as a working gap for the function "brakes" Gap 48 between the cylinder 50 and a cylinder 53 of a rotor 54 of an output shaft 55, however, is used as a working gap for the function "clutch". By the two field generators 49,56 can by a corresponding generating the magnetic B fields, the individual functions are also displayed independently of each other.

Should by a magnetic actuator 58 gem. Fig. 5, the functions "brakes" and "drive" are shown, it requires for the function "brakes" one with a

magnetorheological medium filled gap 59 and for the function "drive" of an air gap 60. Since there is no need for a function "clutch", the drive and the output shaft can be combined to form a common, continuous shaft 61. In this embodiment, an inner and an outer field generator 62,63 are provided, the B-fields can develop the same or opposite effect. FIGS. 6 to 9 show schematically radially wound winding packages. If these are individual coils, the

Winding packages 65, 66; 67.68 of a phase in

Parallel circuits both in an internal

Field generator according to FIG. 6 as well as an external field generator according to FIG. 7 directly in one

Operated in parallel, wherein by the

alternating winding direction of the winding packages 66,67 and 67,68 an axially changing field orientation can be achieved.

FIG. 8 shows winding packages 69, 70 in the case of an internal field generator, FIG. 9 winding packages 71, 72 in the case of an external field generator, in which a continuous winding wire 73, 74 axially has an alternating winding direction, such that a series connection

opposite oriented winding packages 69,70 and 71,72 arises.

Axially extending winding packages and their

Verschaltung will continue with reference to the figures 10 to 13 explained, which are designed for a common 3-phase voltage and can be used both for the formation of an inner and an outer field generator. Fig. 10 shows in a cross-section six winding packages 76-81, twice the number of the here

predetermined phases. As FIG. 11 further shows, two winding packages 76, 79; 77.80; 78.81

counteracted with reference to the

Cross-sectional view acc. Fig. 10 diametrically

are opposite.

The two winding packages 76, 79; 77.80; 78,81 are interconnected on one side in a star 82, the

additionally a controllable current i ₀ through a

Control circuit is imposed.

Alternatively or additionally, with a controllable current i _0, a separately formed winding 84 of a

Field generator 85 are acted upon, cf. FIGS. 12 and 13.

As described above, winding packets 86-91 are arranged spatially immediately one after the other and operated in pairs in a star connection at a three-phase voltage. A loading of this three-phase voltage with a controllable current i ₀ is not required, but is here with the controllable current i ₀ from six

Winding packages 93-98 existing, trained separately winding 84 acted upon. These winding packages 93-98 are arranged here directly successive over the circumference and connected in series in opposite directions. In particular radially extending windings can be used for the generation of a static field, so also for the application of a controllable current i ₀ . FIG. 14 shows a drive circuit, in particular for such radially extending windings, designed as a 1-Q positioner

100, which enables the placement in the mathematically first quadrant of a diagram U ₀ over i ₀ . For the sake of simplicity is here and are in the other representations preferred switch configurations gem. Fig. 15 only as

Combination of switch T _x and protection diode D _x shown.

The drive circuit acc. Fig. 16 shows a 2-Q controller

101, which allows the placement in the mathematically first and third quadrants U ₀ over i ₀ , while the 4-Q controller 102 gem. Fig. 17 allows the placement in all quadrants in the diagram U ₀ over i ₀ .

The above-described drive circuits for the generation of a static field, caused by the controllable current i ₀ , can find particular use in connection with a pulse inverter 103 here three branches 104-106 for the generation of a three-phase rotating field, so that there is a superposition of the Rotating field with the static field comes.

Alternatively, optionally in combination, it allows a pulse change switch 107 gem. 19 with m + 1 branches, in this case four branches 108-111, to impress the controllable current i _{0 to} the windings 112-114 combined in a star connection, cf. also Fig. 11.

The same is true with a number of phases of the rotating field corresponding number of H-bridges 116-118. Fig. 20 possible. Fig. 21 shows a matrix converter 120, whose three branches 121-123 here correspond to the number of phases corresponding to three

Windings 124-126 created create a rotating field, which a static field with drive circuits gem. can be superimposed on Figs. 14, 16 and 17, or, as shown in Fig. 21, has an m + 1 branch 127, which is connected to the together in a star 128 windings 124-126.

Based on the Fig. 22,23, the control of a

Clutch actuator having motor function further explained, the mathematical description of a

Space pointer representation is based, as explained for example in Leonhard, W., Regulation of electric drives, Springer Verlag 2000.

The torque of the motor is proportional to the product of the flux linkage v | _R and the corresponding, orthogonal stator current i _Sq and can be in the selected

Space vector representation by

express with P the Pohlzahl, L _{h of} the main inductance and L _{R of} the rotor inductance.

As further sizes are shown in Figs. 22,23 U _sa

U _sb , U _so as the conductor voltages of the motor, co _FS as

Circular velocity of the flow pointer, as the

pole-pair-dependent angular velocity of the rotor and ω _ΡΗ as the difference in the angular velocity of the rotor and the rotor

River pointer. The generatable clutch torque T _c is a function of the magnitude of the magnetic flux density, taking into account the geometry of the shear gap. By an extension, the clutch torque T _c by the already present in the usual, linear model of an asynchronous machine

Rotor flux are described. Thus, that can be

Clutch torque T _c as a non-linear function

represent, highlighted in Fig. 22 by the dash-dotted outline.

By a corresponding control of the rotor flux can, due to the above-explained relationship with the behavior of the rotor flux according to the differential equation

the desired clutch torque T _{c can be set} via the stator current i _sd . At the same time, a

Operating point-dependent, maximum possible motor torque T _M via the control of i _sd orthogonal stator current i _Sq taking into account the rotor flux ψ _Ε .

The corresponding control variables in this case represent the two setpoint torques of the motor T _M ^* and of the clutch T _c ^* , which are defined by the current i _Sq ^* and the magnetic flux

to be discribed:

, , 2 1

Ψ * = Ν - * (Τα)

This control concept with the two torques T _M ^* and T _c ^* as reference variables is reproduced in FIG.

Claims

Method for the operation of a magnetic actuator Claims:

A method of operating a magnetic actuator for transmitting and / or generating torque, comprising a drive shaft and an output shaft to which the field-excited forces of a magnetorheological

Medium in at least one gap between the

Drive shaft and the output shaft act, characterized in that an m-phase rotating field is applied to at least one field generator and that the rotating field has a controllable current (i ₀ , i _sd , i _Sq ).

2. The method according to claim 1, characterized in that the controllable current comprises a DC component.

3. Method according to one or more of the preceding

Claims, characterized in that the controllable current has a time-dependent and / or dependent on the position of the drive shaft to the output shaft and / or a load component.

4. Method according to one or more of the preceding

Claims, characterized in that at least one separately formed winding of a field generator is acted upon by a controllable current.

5. The method according to claim 4, characterized in that the winding has 2m winding packets and that the winding packets spatially directly to each other

arranged sequentially and connected in opposite directions in series and / or in parallel. Method according to one or more of the preceding claims, characterized in that by the

Rotary field 2m winding packets are applied and that the winding packets are spatially connected in each case in an arrangement n-th winding package with (n + m) -tem winding packet in series and / or in parallel.

Method according to one or more of the preceding claims, characterized in that a radially extending winding packet is controlled by a drive circuit such that a static field is generated.

A method according to claim 7, characterized in that the drive circuit is designed as a 1-Q controller or as a 2-Q controller or as a 4-Q controller.

Method according to one or more of the preceding claims, characterized in that axially extending winding packets are controlled by a drive circuit such that a rotating field is generated.

0. Method according to claim 9, characterized in that the drive circuit is designed as a pulse inverter with m branches or as a pulse inverter with (m + 1) branches or by m H bridges or as a matrix converter.

1. The method according to one or more of the preceding

Claims, characterized in that the magnetic flux generated by fields by a magnetic hysteresis exhibiting and / or by a magnetic and / or by a magnetically anisotropic material receives a preferred direction.