DE102012112841A1 - Voltage-based method for controlling an operating position of e.g. electromagnetic hydraulic of high friction clutch gear in motor vehicle, involves setting pulse length of overlapping pulses less than pulse length of voltage pulses - Google Patents

Abstract

The method involves driving an actuator with the current pulses (10) corresponding to a desired actuator position by obtaining the specification of voltage pulses (24) with the predetermined pulse parameter, by an operation solenoid. The voltage pulses are overlapped with the overlapping pulses (26). The pulse length (30,34) of the overlapping pulses is set less than the pulse length of the voltage pulses to adjust the voltage pulses associated with the predetermined slope of the current pulses. Independent claims are included for the following: (1) a method for calculating duration and level of the overlapping pulses; and (2) a control device for controlling operation solenoid.

Description

The present invention relates to a voltage-based method for controlling a current flow through an electromagnet, in particular for controlling an operating position of an electromagnetic hydraulic valve according to the preamble of claim 1. Furthermore, the invention relates to a method for calculating a duration and amount of heterodyne pulses for use in such Method and a control device for controlling the operation of an electromagnet, in particular for controlling an electromagnetic hydraulic valve.

STATE OF THE ART

From the EP 0306839 a method and a device for driving switched electromagnets, in particular in injection valves for internal combustion engines, known. In order to optimize the drive, and in particular to reduce the turn-on delay, a short pulse of high voltage is passed through the electromagnet, which is dimensioned so that no thermal overloads occur. Subsequently, only a small holding energy, z. B. a constant holding current supplied to the electromagnet. With such a control, the turn-on delay compared to conventional controls can be significantly reduced; In addition, the turn-off delay is lower. The method is optimized for switched solenoids and covers the use of electromagnets, for example in proportional valves or for pressure control, especially in valves with high system friction, from insufficient.

Developments in transmission technology relate to electromagnetic hydraulic valves for comfortably frictionally to be coupled to gearbox clutches, especially start / clutches or synchronizers that allow the use with little to no gear oil changes. Moreover, such hydraulic valves should be used when using poor quality transmission fluid, for example in developing countries. For this purpose, usually hydraulic valves with particularly narrow air gaps of the driving electromagnets are used in order to reduce the inhibiting influence of possible dirt particles in the oil. Such hydraulic valves have an increased friction, resulting in the proportional control operation to a high cost of electronic control, which is carried out in current regulated in most cases. A high-quality current regulation is insufficiently feasible in a motor vehicle, since no ideal voltage source is available in order to be able to specify a desired current profile. Furthermore, a current-based control of an electromagnet requires a high semiconductor cost with corresponding hardware costs and implies a high susceptibility to errors.

From the US 20020101314 For example, an electromagnetic actuator is known which serves as a drive in a hydraulic valve. The actuator is designed so that the hysteresis of the mechanical positions of a movable iron core as the armature of the electromagnet is small compared to the value of the electric current through the coil of the electromagnet which can be minimized. The hysteresis behavior of such electromagnetic hydraulic valves can be attributed essentially to three influences: the flow force of hydraulic flows, which depends not only on the type of hydraulic oil but also on its temperature or its viscosity, the magnetic hysteresis, which depends on the selected magnetic material, as well as the friction, in addition to the coefficient of friction, or the selected material pairings significantly depends on the lateral forces on the anchor. The US 20020101314 describes a magnetic design of an electromagnetic actuator which is dimensioned so that even with a certain eccentricity of the movable armature of the electromagnet, the lateral force between the housing and armature can be minimized in order to minimize the frictional force on the armature can also. This describes measures which can be taken on the part of the design of an electromagnetic actuator in order to favor a frictional operation. Further possible measures for optimizing the operating behavior of such an electromagnetic actuator, in particular with regard to the electrical control of the actuator, are not taken into account.

Starting from the above-described prior art, it is an object of the invention to provide a method for controlling a current flow through an electromagnet, a method for calculating a duration and amount of heterodyne pulses for use in such a method and a control device for controlling the operation of an electromagnet , wherein said methods and the control device can be used in particular for heavy-duty electromagnetic hydraulic valves with high friction, eg high static or sliding friction, so that safe operation of such hysteresis electromagnetic actuators can be ensured even with a high system friction coefficient with minimal maintenance and minimal failure rate , A high system friction can be caused, for example, by a tight bearing clearance of the displaceable mechanical parts of the actuator, or by a transverse force with which an armature magnet is pulled against a wall of the actuator housing. Such friction forces are In particular, increased when an air gap between the armature magnet and a magnetic separation layer of a surrounding pole tube of the actuator are very low, ie only a slight mechanical clearance is given.

This object is achieved by a voltage-based method for controlling a current flow through an electromagnet according to the teaching of claim 1, a method for calculating a duration and amount of heterodyne pulses for use in such a method and a control device for controlling the operation of an electromagnet according to the other sibling Claims solved. The dependent claims suggest advantageous developments of the invention.

DISCLOSURE OF THE INVENTION

In a first aspect of the invention, a voltage-based method for controlling a current flow through an electromagnet, in particular for controlling an operating position of an electromagnetic hydraulic valve is proposed, wherein the electromagnet for driving an actuator with current pulses corresponding to a desired Aktorstellung, or compliance with a desired setting position by default Voltage pulses are applied to at least one predeterminable pulse parameter. In the method according to the invention, overlapping pulses whose pulse length is smaller than the pulse length of the voltage pulses are superimposed on the voltage pulses in order to set the profile of the current pulses associated with the voltage pulses, in particular in order to set a predefinable edge steepness of the current pulses.

Accordingly, the electrical control of electromagnets, as used for example for the operation of electromagnetic hydraulic or pressure control valves, take place via a regulation of the input voltage to the electromagnet. This voltage regulation makes lower demands on the hardware of a control device than a current control and can be carried out even with fluctuating supply voltage with sufficiently high quality. Thus, the control device is inexpensive, the control characteristics, such as. Current pulse shapes, however, are only indirectly adjustable, since the inductance and the ohmic resistance of the magnetic coil of the electromagnet influence by their low-pass character, the current pulse shapes and to a rounding of a desired rectangular shape, as often used in a pulse width modulation, lead. Such a smoothed current path indicates precise operation of the electromagnet, e.g. in a hydraulic or pressure control valve, certain restrictions. The proposed invention allows using a cost-effective control device with a voltage regulation to achieve the high-quality behavior of a current control. In this case, a voltage control over a current control has the excellent advantage that it is more similar to a control than a current control, since the influence of the feedback is lower. Controls are much easier to handle in operation than regulations, have no instabilities and are therefore more robust and less error prone.

The inventive method proposes generating a voltage superposition (dither) for controlling electromagnets, in particular when used in electromagnetic hydraulic or pressure control valves, wherein the voltage overlays in the form of heterodyne pulses via a voltage pulse, which defines a basic operating state of the electromagnet. In other words, using a voltage-controlled superimposition of heterodyne pulses via a basic voltage pulse, a current course which is favorable for the actuation of electromagnets is generated. The controlled voltage superposition results in a current characteristic with an adjustable, in particular high, edge steepness of the resulting current pulse, e.g. a rectangular current waveform achieved. Preferably, with such a voltage-based control, a pressure control valve can be operated for a clutch transmission, wherein in the case of a double clutch avoided an undesirable shift shock and a clean, smooth gear change can be vorgenomen. Such pressure control valves have a high coefficient of friction, wherein the control movements of the armature magnet are small, so that a precise, fast-acting control is advantageous.

Frequently, the pulse width modulation is used to control electromagnets in order to set an average current profile, which can be varied via the so-called duty cycle. In this case, the duty cycle at a fixed pulse frequency is usually defined as the ratio of the pulse length at a voltage, for example a reference voltage, to the pulse length at a second voltage, for example voltage zero within the cycle time.

For a comparison with the prior art improved control of an electromagnet, an advantageous voltage control has proven to be at least two-stage, in particular four-stage voltage superposition. In this case, to influence the course of the rising and / or falling edges favorable, a corresponding control device a high-frequency Deliver voltage. This leads to a high recharge speed, or a high-frequency current course within the inductance of the magnet coil, to the desired steep flanks of the current pulses. It can then be switched back to a duty cycle, which corresponds to a mean current pulse for the rest of the voltage half-wave, ie a low-frequency voltage waveform can be adjusted to generate a constant current level corresponding to a desired magnetic field strength of the solenoid or position of the proportional valve. Thus, with a multi-level, in particular four-level voltage superimposition by means of a voltage control, a desired, in particular rectangular, current profile through the electromagnet can be achieved. By knowing the frequency characteristic of the electromagnet, a desired current profile can be set by means of a high-frequency controlled voltage excitation. For this purpose, for example, a frequency analysis, in particular an FFT or DFT (Fast or Discrete Fourier Transformation) of the electromagnetic-mechanical system are made to find a suitable voltage waveform for setting a desired current flow through the solenoid or switching behavior through the solenoid valve, and this specify by combining a voltage pulse and overlay pulse.

By virtue of the method according to the invention, a hysteresis property of an electromagnetic actuator caused by high mechanical friction can be alleviated, the required drive energy being significantly reduced and thus the efficiency improved and the energy consumption of the actuator can be reduced. The response speed of the actuator is increased, thus achieving a higher switching dynamics. Since the power consumption can be reduced, the life is increased, whereby due to the improved dynamic behavior, a high control quality and repeatability of switching operations can be achieved.

According to an advantageous further development of the invention, the superposition pulses can be synchronized in time with the voltage pulses and / or with rising and / or falling edges of the voltage pulses. In order to achieve the steepest possible course of the rising and / or falling edges, it is expedient to merge the beginning of overlapping pulse and voltage pulse, or make a fixed correlation of these pulses.

According to an advantageous development of the invention, the pulse length and / or pulse height of the voltage pulses and / or the superimposition pulses can be determined from an equality of a time-integrated surface under a positive and a negative half-wave of a predefinable pulse frequency, based on a predefinable regulator voltage. In this case, the equality of the time-integrated surfaces allows a controller-neutral behavior of the superimposed voltage signal. Hereby, the remanence of the electromagnet can be completely degraded, and thus a fast switching behavior can be achieved.

As a parameter for controlling the amplitude, that is to say the pulse height of the superposition pulses, an area can be defined as the desired value of the amplitude. This represents a suitable measure of the energy content of the superposition pulses and allows its form-neutral definition. Furthermore, switching effects resulting from the multilevel voltage specification are thus suppressed. In order to enable a frequency-neutral behavior of the surface definition, the surface can also be normalized to the frequency. Also can be conveniently switched to a coextensive low or higher frequency control.

The calculation of the necessary pulse lengths and pulse heights of the superposition pulses can advantageously be carried out via a multi-step algorithm, wherein the algorithm can generate a multi-level, in particular four-level voltage superimposition under the specification of a guaranteed equality of the voltage surface between the positive and negative half-wave of the voltage curve.

N_{pos_ges}

= Anzahl von Spannungspulsen der positiven Halbwelle,

N_{neg_ges}

= Anzahl von Spannungspulsen der negativen Halbwelle,

U_ref

= Referenzspannung eines Stromreglers bei gewünschter Aktuatorstellung,

U_regler

= Reglerspannung, maximale Ausgangsspannung des Reglers sind.

To this end, the following is an example of a four-stage voltage superposition with four time ranges I, II, III and IV for simulating a Stromreglerverhaltens considered that defines a voltage _overlay that would output a comparable current controller with a current-based regulated voltage U _regulator for a desired actuator position. In this case, in a first step, two limiting halfwaves (areas I & II or areas III & IV) of the switching cycle are considered, and the sizes of the maximum possible voltage time areas of the positive half cycle of a voltage pulse A ₁ (area I and II in 2 ) and a negative half wave A ₂ (regions III and IV in FIG 2 ) to simulate the current regulator voltage level U _regulator . For the maximum voltage time areas applies: A ₁ = N _{pos_ges} · (U _ref - U _controller ) and A ₂ = N _{neg_ges controller} , determined, where

N _{pos_ges}

= Number of voltage pulses of the positive half-wave,

N _{neg_ges}

= Number of voltage pulses of the negative half-wave,

U _ref

= Reference voltage of a current controller at the desired actuator position,

U _regulator

= Regulator voltage, maximum output voltage of the regulator.

The maximum allowed area can be defined as the minimum of A ₁ and A ₂ by A _limit = Min (A ₁ , A ₂ ) be determined. Thus, the limiting area A _limit is further selected as the minimum from the physically determined maximum interface (A _limit ) determined above and an inertially predetermined overlay area (A _dither ): A _limit = Min (A _dither , A _limit )

N_{p_soll}

= Soll-Anzahl an positiven Überlagerungspulsen bestimmt.

The next step is to determine the area of the positive half-wave. In this case, an area for the desired number of positive overlay pulses (area I in 2 ) above A _1p = N _{p_soll} · U _ref - U _controller ) With

N _{p_soll}

= Set number of positive overlay pulses determined.

If A _1p lies within the limiting area A _limit , the actual number of positive beat pulses N _p
N _p = N _{p_soll be} set, if not, then becomes, then becomes
N _p = integer division (A _limit / (U _ref - V _controller )).

Thereafter, the area used for the positive overlap pulses (area I in 2 ) A _1p = N _p · (U _{ref -regulator} ) and the area of the "regular" voltage pulse (area II in 2 ) with A _2p = A _dither - A _1p .

This results in the voltage of the "regular" voltage pulse U _dither = A _2p / (N _{pos_ges} - N _p ).

This is a complete calculation of the positive half-wave, which can be generated within the specifications of a control device.

N_{n_soll}

= Soll-Anzahl an negativen Überlagerungspulsen ermittelt.

Subsequently, the area of the negative half-wave is determined. In this case, an area for the nominal number of negative superposition pulses (area III in FIG 2 ) above A _1n = N _{n_soll} · U _controller

N _{n_soll}

= Set number of negative overlay pulses determined.

If A _{1n is} within the limiting area A _limit , the actual number of negative beat pulses N _n becomes
N _n = N _{n_set} set, if not then becomes
N _n = integer division (A _limit / U _controller ) set.

Thereafter, the area used for the negative beat pulses (area III in FIG 2 ) A _1n = N _n · U _controller and the area of the "regular" voltage pulse (area IV in 2 ) with A _2n = A _limit - A _1n .

This results in the voltage of the "regular" voltage pulse U _dither = A _2n / (N _{neg_ges} - N _n ).

This is a complete calculation of the negative half-wave, which can be generated within the specifications of a control device.

By this calculation _rule , a four-stage voltage _{superposition pulse} is calculated with four time period _ranges , which corresponds to an average voltage _output U _regulator , wherein a hysteresis responsiveness of the actuator can be considered.

The superposition pulses are not necessarily shorter in time than current pulses of a comparable current-based control. However, they can achieve the same effect at reduced currents or reduced duty cycle, in particular when the required level of current pulses is higher than a current control can provide real achievable amplitudes. In this case, the superimposition pulses can also be designed in three or two stages or consist only of superpositions, and can also assume any intermediate forms depending on the calculation specification, characteristic map or calculation.

The dither pulses can assume a typical frequency of 100-300 Hz, wherein when used for example for controlling a pressure regulating valve in a transmission, a frequency of 150 Hz can be set. As a result, the PWM signals (pulse width modulation signals) for shaping the voltage superimposition have an approximately 10 to 20 times higher pulse frequency, resulting in PWM pulse frequencies of up to 3 kHz to 6 kHz, which can be provided inexpensively with conventional robust electronics.

According to an advantageous development of the invention, the voltage pulses can be pulse width modulated, pulse height modulated, pulse frequency modulated and / or pulse phase modulated. These types of pulses can be easily and conveniently generated by standard components and easily set in their parameters. The application of heterodyne pulses to drive electromagnets may conveniently be applied to other types of modulation.

According to a further advantageous embodiment of the method, the voltage pulses and / or the superimposition pulses can represent square-wave pulses; in particular, the total voltage pulse can assume four different voltage levels. A four-level voltage superposition represents a very favorable feature of the method according to the invention, since on the one hand it can favorably influence both rising and falling edges of the current pulses and, on the other hand, represents a variant with low complexity in the implementation in a control device of simple design.

According to an advantageous development of the invention, a lower limit value of the voltage pulses greater than zero and / or an upper limit value of the voltage pulses can be set smaller than a reference voltage derived from a voltage source. Such a setting is favorable, since there is still enough leeway for the control with superposition pulses from the power supply.

According to an advantageous development of the invention, the pulse height of the superimposition pulses can be varied between zero and the reference voltage, wherein maximum influencing of the current pulse shapes is given by maximum possible pulse heights of the superposition pulses.

Various strategies are conceivable in order to ensure a still favorable waveform of the superposition pulses, even with over or under voltage of the supply voltage. For example, buffer blocks or filters can be used to smooth and stabilize the supply voltage.

Starting from one of the two aforementioned embodiments, when a predetermined limit voltage is exceeded by the reference voltage, the pulse height and / or the pulse duration and / or the duty cycle of the voltage pulses can be reduced to effect setting of a constant current for operation at the limit voltage current through the electromagnet. This makes it possible to compensate for fluctuations in the supply voltage upwards for the operation of the electromagnet and to achieve a constant transhipment rate of the inductance of the electromagnet.

Starting from one of the aforementioned exemplary embodiments, the pulse height and / or the pulse duration and / or the pulse duty factor of the voltage pulses can be increased when the reference voltage falls below a predetermined limit voltage, in order to effect the setting of a current profile through the electromagnet which remains constant for operation at the limit voltage. This makes it possible to compensate for fluctuations in the supply voltage downwards for the operation of the electromagnet and to achieve a constant transhipment rate of the inductance of the electromagnet.

According to an advantageous embodiment of the invention, the method for controlling an electromagnetic hydraulic or pressure control valve can be used with high frictional forces. In particular, the method is suitable for the control of a valve in a clutch transmission of a drive train, for example in a dual-clutch transmission of a land, sea or aircraft, by a pressure control by means of the valve, a clean gear change by the two friction clutches is feasible. The occurring rule movements are comparatively low, demenetsprechend must be possible to a precise control. As already stated above, have hydraulic valves with high friction forces such as static friction or sliding particularly large hysteresis in their response, so that they do not respond when energized initially, and show a overshoot when exceeding a minimum voltage, so that a fast and reliable setting on a desired opening position is difficult to reach. When used in a dual clutch, this leads to an unpleasant shift shock, a so-called overlap control from one friction clutch to the other friction clutch. For this reason, current-controlled regulator methods have been used to control such valves, which require a corresponding hardware cost and drive up component costs. In this respect, their operation can be particularly favorable by the use of the method according to the invention and thus given a positive influence on the edge steepness of the current pulses be designed without the need for complex power control.

In a sibling aspect of the invention, a method for calculating a duration and amount of beat pulses for use in a method according to one of the aforementioned embodiments is proposed. At least one first characteristic field for a number of positive and at least one second characteristic field for a number of negative superposition pulses is generated in a test bench run with an electromagnetic actuator with hysteresis-type response, in particular with an electromagnetic hydraulic valve with high system friction coefficients, by triggering with voltage pulses and heterodyne pulses and current pulses generated therefrom determined, wherein a number and / or an amplitude of the overlap pulses is varied in order to minimize a deviation of the current pulses generated by the voltage pulses and the overlap pulses from a predetermined current pulse curve. The current pulse curve can be obtained from an already known, current-controlled method

With such an optimization algorithm, when operating on a test bench for different operating points, i. Opening positions of the actuator map parameters are determined, which result in the best possible agreement with an example rectangular predetermined target current profile. The required maps can be generated automatically and the time required for a manual calculation of maps reduced to completely avoided. Another advantage is the independence given by the test bench operation and non-influencing the use in a real environment, such as a vehicle. In this way, an automatic parameterization of the maps for a desired number of nodes can be achieved.

In this case, advantageously, the first and the second map can be identical. For certain applications, it may also be beneficial to provide the electromagnetic actuator in critical operating situations with a more effective control in the form of a single neutral map.

According to an advantageous development of the invention, at least the first and / or the second map can be approximated by means of a mathematical function and / or a model-based approach can be used to determine the maps. This embodiment has the advantage that the use of the u.U. memory-intensive maps can be dispensed with in a control device, with the proviso that for a computationally intensive process for function calculation and / or model calculation can be used. Thus, instead of a map, a formula description, polynomial, spline, Taylor or PWM weighting parameter set, or other approach functions may be stored to reduce the set of map data.

According to a further aspect of the invention, a control device for controlling the operation of an electromagnet, in particular for controlling an electromagnetic hydraulic valve, is proposed, wherein the electromagnet for driving an actuator is subjected to voltage pulses. The control device comprises a voltage setting device for the predeterminable delivery of voltage pulses to the electromagnet. The voltage setting device is set up for outputting superposition pulses whose pulse length is shorter than the pulse length of the voltage pulses in order to set the course of the current pulses associated with the voltage pulses, in particular to set a predefinable or desired edge steepness of the current pulses.

According to an advantageous embodiment of the invention, the control device may comprise a memory device for permanently storing the course and height of the voltage pulses and the overlapping pulses, wherein preferably an I / O interface device for external programming, i. at least for storage but also advantageous for reading the data of the memory device is provided. For example, the memory device may include the above-mentioned first and second maps for controlling the electromagnetic actuator or parameter and function descriptions that can simulate the maps or pulse sequences by means of a computer-based method. Furthermore, it is expedient to have a correction possibility for changes in the two maps and / or parameter inputs and changes via an I / O interface device.

According to an advantageous development of the invention, the control device may include a driver stage for direct control of an electromagnet of an electromagnetic hydraulic valve and / or a diagnostic device for monitoring the operation of the control device and / or the hydraulic valve. In order to allow a particularly compact design of the control of the electromagnetic actuator, it is advantageous to provide a driver stage in the control device itself, as is often realized in vehicle control devices. Also, a diagnostic option for monitoring the operation of the control device for maintenance is very helpful, for example, the driver stage can be configured externally directly addressable, or the pulse trains of the control device can be read from the outside and the I / O interface device can be contacted. It offers further advantageous to arrange a bus coupler, such as a CAN bus coupler in the control device to provide communication with a higher-level engine control system to receive desired switching positions of the actuator and output operating and fault data. In this case, fault cases and / or a need for maintenance of controlled hydraulic valves can be determined so low.

DRAWINGS

Further advantages result from the present description of the drawing. In the drawings, embodiments of the invention are shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Show it:

1 a voltage and current waveform for driving a solenoid according to the prior art;

2 a voltage and current waveform for driving an electromagnet according to an embodiment of the invention;

3 an electromagnetic hydraulic valve for application of the method according to the invention according to a further embodiment;

In the figures, the same or similar components are numbered with the same reference numerals.

1 shows a typical voltage and current waveform for driving an electromagnet 126 , such as in 3 as electromagnetic hydraulic valve 100 executed, according to the prior art. Shown is a predetermined regulator voltage curve U of an input voltage to an electromagnet over time t. The predefined voltage curve shows a sequence of square-wave pulses 24 by a mean regulator voltage U _regulator 14 that is between an upper and a lower limit voltage 13 . 15 vary. The upper limit voltage 15 is less than a reference voltage 16 , which is derived from a voltage source, such as a vehicle electrical system voltage of a vehicle. The lower limit voltage 13 is greater than zero. The voltage pulses 24 are characterized by one rising and one falling edge 38 . 40 , a voltage pulse height 21 . 23 as well as by a voltage pulse length 20 . 22 , One positive half-wave (range I) and one negative half-wave (range II) around the average regulator voltage 14 each form a switching period whose reciprocal corresponds to a pulse frequency.

Also drawn is the adjusting current curve from individual current pulses 10 , characterized by the voltage-based control of the electromagnet 126 with the voltage pulses 24 results. Due to the mutual inductance and the resulting low-pass characteristic of the electromagnet 126 are the current pulses 10 against the applied voltage pulses 24 strongly rounded or low-pass filtered, since the current after applying a voltage edge 38 . 40 due to the mutual inductance only slowly reaches its full height and slowly decreases in binary falling voltage edge during the degradation of the stored magnetic energy in the magnetic coil. With such a voltage-controlled control only imprecise switching positions of an actuator can be achieved with long response times.

2 provides a voltage and current curve for controlling an electromagnet 126 according to an embodiment of the invention. The in 1 illustrated voltage pulse 24 becomes in the time domain I an overlay pulse 26 superimposed, whose overlap pulse length 30 shorter than the original voltage pulse length 20 is, its overlay pulse height 31 but significantly larger, namely equal to the reference voltage U _ref in the illustrated example. The voltage pulse length remaining in the region of the positive half-wave of the time ranges I & II 32 and the overlap pulse length 30 add up to the original voltage pulse length 20 from 1 ,

The negative half-wave of the voltage pulse 24 in the time ranges III & IV is with a negative overlay pulse 26 with the overlap pulse length 34 and the overlay pulse height 35 , which is conveniently at zero voltage, superimposed. Here, too, overlap pulse lengths add up 34 and remaining voltage pulse length 36 to the original voltage pulse length 22 from 1 , The current waveform shown shows due to the control with overlay pulses in the time ranges I and III, which can be fully controlled by a voltage zero and the reference voltage, and the reduced voltage levels in the time ranges II and IV a significantly faster increase, or decrease of the current pulses 10 as in 1 , This causes the valve 100 provides a shortened response time, sets a desired opening position more accurately and can achieve a higher switching frequency.

3 shows an electromagnetic hydraulic valve 100 for applying the method according to the invention according to a further embodiment. This is a Volume flow control valve in basic position, as it can be used for example for controlling and regulating hydraulic processes.

The hydraulic valve 100 consists of an electromagnet 126 in a housing 112 is arranged and over a pestle 124 a hydraulic piston 122 , which is located in the same valve housing and represents the actual actuator drives. The electromagnet 126 comprises a ring-shaped magnet coil 102 that with the case 112 is firmly connected for example by a potting compound. Inside the magnetic coil 102 there is a pole tube 104 in which, through a thin air gap 106 separated, an anchor 108 , usually designed as an iron core, can move.

In order to have a fail-safe behavior at large gear oil change intervals - extreme life cycle filling - the hydraulic valve should 100 favorably have a high robustness. High robustness can indeed be achieved with a great play on the parts to be moved. However, this is at the expense of the energy balance and leak tightness. The high degree of robustness is achieved by dirt particles in the hydraulic oil not jamming the hydraulic valve 100 can lead, otherwise the anchor 108 must apply very large axial forces in order to always tear free. The hydraulic valve 100 Nevertheless, has a high control quality, which is achieved by means of several design measures. In particular, the transverse forces between the anchor 108 and the pole tube 104 minimized. Such a constructive feature for reducing lateral forces is a very tight running clearance between the armature 108 and the pole tube 104 by means of a very thin separating layer 110 instead of, for example, a sleeve or a thick coating is achieved. The strength of such a thin separating layer 110 may be, for example, at a layer thickness of 0.01 mm to 0.06 mm. Here are PTFE layers, but also chemical nickel plating or similar materials conceivable.

Such a flow control valve 100 is intended for example for the insertion and disengagement of the gears in a vehicle automatic transmission. The hydraulic valve 100 has two working ports A and B, and a supply port P. Moreover, the hydraulic valve points 100 also two tank outflows T1 and T2, on. A hydraulic piston 122 has three circumferential annular grooves 114 . 116 . 118 on. By means of the middle ring groove 116 is a volume flow of an axially arranged between the two working ports A, B supply port P on the rear working port B feasible when the hydraulic piston 122 in the in 3 illustrated basic position with de-energized coil 102 located. The front working port A is in this basic position on the front annular groove 118 led to the rear tank drain T2. However, a sufficiently large voltage is applied to the coil 102 created, so is the hydraulic piston 122 in a against the spring force of the helical compression spring 120 maximum disengaged position. In this maximum disengaged position, the hydraulic oil is conducted from the supply port P to the front working port B. The rear working port B is in turn via the rear annular groove 114 led to the front tank drain T1.

The valve shown has - comparable to a pressure control valve a tight Spatmass and thereby high adjustment forces, so that high Mischreibungs- and sliding friction forces result in dynamic operation.

The illustrated hydraulic valve 100 , as well as a genus-like pressure control valve for a transmission, in particular dual-clutch transmission due to its high coefficient of friction and its hysteresis adhesion excellent, with an embodiment of the method according to the invention, for example with a four-stage voltage superposition after 2 to be controlled, the overlap pulse length and the overlay pulse height are determined by the method described. Next, the control of the hydraulic valve takes place 100 Advantageously with a control device according to the invention for controlling the operation of the electromagnet. The illustrated hydraulic valve 100 that has a narrow air gap 106 , Thus, high system friction and thus has correspondingly strong hysteresis behavior, can be operated with the inventive method with minimal maintenance and minimal failure rate accordingly advantageous. In the case of a pressure regulating valve, exact compliance with the re-position can be achieved with a reduced reaction time when the setpoint value is changed by the actuation method.

LIST OF REFERENCE NUMBERS

10

 current pulse

12

 Zero voltage lower

13

 Grenzspannunng

14

 voltage regulator

15

 Upper limit voltage

16

 reference voltage

18

20

 Voltage pulse length I

21

 Voltage pulse height I

22

 Voltage pulse length II

23

 Voltage pulse height II

24

 voltage pulse

26

 Superposition pulse

30

 Superposition pulse length I

31

 Overlay pulse height I

32

 Voltage pulse length II

33

34

 Superposition pulse length III

35

 Overlay pulse height III

36

 Voltage pulse length IV

37

38

 Rising edge

40

 Falling edge

100

 hydraulic valve

102

 Kitchen sink

104

 pole tube

106

 air gap

108

 anchor

110

 coating

112

 casing

114

 Rear ring groove

116

 Middle ring groove

118

 Front ring groove

120

 Helical compression spring

122

Actuator = hydraulic piston

124

 tappet

126

 electromagnet

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0306839 [0002]
• US 20020101314 [0004, 0004]

Claims (16)

Voltage-based method for controlling a current flow through an electromagnet ( 126 ), in particular for controlling an operating position of an electromagnetic hydraulic valve ( 100 ), wherein the electromagnet ( 126 ) for driving an actuator ( 122 ) with current pulses ( 10 ) according to a desired actuator position by presetting voltage pulses ( 24 ) is acted upon by at least one predeterminable pulse parameter, characterized in that the voltage pulses ( 24 ) Overlapping pulses ( 26 ) whose pulse length ( 30 . 34 ) smaller than the pulse length ( 20 . 22 ) of the voltage pulses ( 24 ) is to the course of the voltage pulses ( 24 ) associated current pulses ( 10 ), in particular by a predefinable edge steepness of the current pulses ( 10 ). Method according to Claim 1, characterized in that the superposition pulses ( 26 ) with the voltage pulses ( 24 ) are synchronized in time, and / or that the superposition pulses ( 26 ) with rising and / or falling edges ( 38 . 40 ) of the voltage pulses ( 24 ) are synchronized. Method according to one of the preceding claims, characterized in that the pulse length ( 20 . 22 . 30 . 34 ) and / or pulse height ( 21 . 23 . 31 . 35 ) of the voltage pulses ( 24 ) and / or the superposition pulses ( 26 ) from an equality of a time-integrated surface under a positive and a negative half-wave of a predefinable pulse frequency, based on a predefinable regulator voltage ( 14 ). Method according to one of the preceding claims, characterized in that the voltage pulses ( 24 ) pulse width modulated, pulse height modulated, pulse frequency modulated and / or pulse phase modulated. Method according to one of the preceding claims, characterized in that the voltage pulses ( 24 ) and / or the superposition pulses ( 26 ) Represent square-wave pulses, in particular that the total voltage pulse can assume four different voltage levels. Method according to one of the preceding claims, characterized in that a lower limit value of the voltage pulses ( 24 ) greater than zero and / or an upper limit of the voltage pulses ( 24 ) smaller than a reference voltage derived from a voltage source ( 16 ) is set. Method according to claim 6, characterized in that the pulse height ( 31 . 35 ) of the superposition pulses ( 26 ) between zero and the reference voltage ( 16 ) is varied. Method according to one of claims 6 or 7, characterized in that when a predetermined limit voltage is exceeded by the reference voltage ( 16 ) the pulse height ( 21 . 23 ) and / or the pulse duration ( 20 . 22 ) and / or the duty cycle of the voltage pulses ( 24 ) is set to the setting by the electromagnets of a current course constant for operation at the limit voltage ( 126 ) to effect. Method according to one of claims 6 to 8, characterized in that falls below a predetermined limit voltage by the reference voltage ( 16 ) the pulse height ( 21 . 23 ) and / or the pulse duration ( 20 . 22 ) and / or the duty cycle of the voltage pulses ( 24 ) is increased by the setting by the electromagnet of a course of current which is constant for operation at the limit voltage ( 126 ) to effect. Use of a method according to one of the preceding claims, characterized in that the method for controlling an electromagnetic hydraulic valve ( 100 ) or a pressure control valve, in particular for use in a clutch transmission, is used with high system friction. Method for calculating duration and height of heterodyne pulses ( 26 ) for use in a method according to one of claims 1 to 10, characterized in that in a test-bench run with an electromagnetic actuator ( 122 ), in particular with an electromagnetic hydraulic valve ( 100 ) or a pressure regulating valve with high system friction, by activation with voltage pulses ( 24 ) and overlay pulses ( 26 ) and resulting current pulses ( 10 ) at least one first map for a number of positive and at least one second map for a number of negative overlay pulses ( 26 ), wherein a number and / or an amplitude of the superposition pulses ( 26 ) is varied to a deviation of the voltage pulses ( 24 ) and the superposition pulses ( 26 ) generated current pulses ( 10 ) to minimize from a given current pulse curve, wherein preferably the first and the second map are identical. A method according to claim 11, characterized in that at least the first and / or the second map are approximated with a mathematical function and / or a model-based approach for the determination of the maps is used. Control device for controlling the operation of an electromagnet ( 126 ), in particular for controlling an electromagnetic hydraulic valve ( 100 ), wherein the electromagnet ( 126 ) for driving an actuator ( 122 ) with voltage pulses ( 24 ), comprising a voltage setting device for the predeterminable delivery of voltage pulses ( 24 ) to the electromagnet ( 126 ), characterized in that the voltage setting device for outputting overlapping pulses ( 26 ) whose pulse length is smaller than the pulse length of the voltage pulses ( 24 ) is to the course of the voltage pulses ( 24 ) associated current pulses ( 10 ), in particular by a predefinable edge steepness of the current pulses ( 10 ). Control device according to Claim 13, characterized in that a memory device for permanently storing the course and magnitude of the voltage pulses ( 24 ) and the superposition pulses ( 26 ), wherein preferably an I / O interface device for external programming of the data of the memory device is included. Control device according to claim 13 or 14, characterized in that a driver stage for direct control of the electromagnet ( 126 ) of an electromagnetic hydraulic valve ( 100 ) and / or a diagnostic device for monitoring the operation of the control device and / or the hydraulic valve ( 100 ) is included. Control device according to one of claims 14 to 16, characterized in that in the control device at least a first map for a number of positive overlap pulses and a second map for a number of negative overlap pulses for controlling the operation of an electromagnet, in particular for controlling an electromagnetic hydraulic valve, can be implemented ,

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