DE102016221477A1 - Device for operating and determining an operating state of an electromagnetic actuator and coupling device and motor vehicle drive train - Google Patents

Abstract

The invention relates to a device for operating and for determining an operating state of an electromagnetic actuator (1). The device has a two-point controller (12) for operating the actuator (1) and a determination means (11C). The determining means (11C) is designed to determine a time profile of the drive signal (H1) output by the two-point controller (12) and to determine therefrom the operating state. The invention also relates to a coupling device (2) with such a device and a motor vehicle drive train with such a coupling device (2).

Description

The invention relates to a device for operating and for determining an operating state of an electromagnetic actuator. The invention also relates to a coupling device with a coupling means for selectively mechanically connecting and disconnecting two components and an electromagnetic actuator for actuating the coupling. The invention also relates to a motor vehicle drive train with such a coupling device.

Electromagnetic actuators are used to realize actuating tasks, for example for the actuation of clutches in motor vehicle transmissions. It is often of great importance to know the current actuator position (= positioning position, which the actuator occupies) for control strategies or safety concepts. In addition, it may often be necessary to know the temperature of the actuator, for example for condition monitoring. Frequently, external sensors are used. However, the cost of external sensors is high. For example, space is required, integration is difficult, cabling must be taken into account and normally the conversion of the sensor signal to a digital signal is required. In addition, the tolerance chain of the components involved leads to inaccuracies. By using so-called inherent measuring effects within electromagnetic actuators, external sensors can be dispensed with.

Methods for the inherent state detection of electric motors are known. Less widely known are solutions for state detection in electromagnetic linear actuators or comparable magnetic actuators. In these actuators, external position measuring systems or proximity sensors are therefore usually used to detect the actuator position.

That in the DE 102005018012 A1 proposed concept of inherent position detection based on the choke coil principle. In the in the DE 102007034768 B3 proposed concept, the so-called hysteresis gain is used.

The object of the present invention is to improve the state of the art.

This object is achieved by the features specified in the main claims. Preferred embodiments thereof are the dependent claims.

Accordingly, a device for operating an electromagnetic actuator and for determining an operating state of the actuator is proposed. The device has a two-position controller for operating the actuator and a determination means. The determining means is designed to determine a time profile of a control signal output by the two-point controller and to determine therefrom the operating state. In particular, a dynamic of the drive signal is determined.

The device is designed to supply the actuator with an electrical current, hereinafter also referred to as "actuator current" on the basis of the drive signal. In accordance with the time profile of the drive signal, a characteristic time profile of the actuator current is formed. Therein, the operating state of the actuator is inherently included, because this determines significantly, the speed at which the Aktorstrom builds up and degrades again, and the maximum and average height of the actuator current.

It has now been recognized that due to the characteristic control of a two-level controller, the operating state of the actuator is also found in the control signal itself. The time course of the actuator current is reflected in the drive signal again. This finding makes use of the invention and accordingly adopts the control signal of the two-position controller in order to deduce from it very simply and precisely the operating state of the actuator.

The electromagnetic actuator is in particular an electromagnetic linear actuator. The electromagnetic actuator may in particular have at least or exactly one coil. Through this coil (s), an armature of the actuator is magnetically movable. This movement can be tapped on the actuator and used mechanically as an actuating movement of the actuator. In this case, the actuator position corresponds to a position of the armature within the actuator or a positioning position which the actuator occupies externally. By means of the device, in particular, an actuator temperature and / or an actuator position of the actuator can be determined. These form accordingly the sought operating state of the actuator.

The proposed concept offers the advantage that only a few means need be used to obtain information about the current operating state of the actuator. This information can be processed immediately, for example, to control or regulate the actuator. By using the integrated sensor effects of the actuator, the tolerance chain can be shortened compared to normally used external sensors.

The two-position controller is preferably an analog two-position controller. In particular, this may be a discrete, ie hardware, two-position controller. With correspondingly fast hardware, the analog two-point controller can also be designed as a software module, for example a control device or another microcontroller.

Preferably, the two-position controller is given an upper current limit and a lower current limit with which it limits the actuator current. The two-position controller also has in particular a comparator circuit and an RS flip-flop (= reset set flip-flop). The two-position controller then toggles the actuator current between the current limits using the comparator circuit and the RS flip-flop, i. the actuator current fluctuates between the current limits. The current limits can be predetermined, for example, by a microcontroller the two-point controller.

Within the two-point controller, the current actuator current, which can be measured, for example, compared with the predetermined current limits. If the upper limit is exceeded, then the energization of the actuator is terminated (= power off). And if the lower limit is undershot, then the current to the actuator is started (= current on). The output from the RS flip-flop signal for the start and the end of the energization of the actuator is preferably used as the drive signal for a bridge driver of a bridge circuit, in particular a so-called H-bridge circuit. This bridge circuit then serves to provide the actuator current. The outputs of the bridge circuit are thus accordingly electrically connected to the inputs of the actuator, in particular the coil of the actuator. The bridge driver drives the bridge circuit according to the drive signal. This in turn causes a corresponding electrical energization of the actuator with the actuator current. This results in the time course of the actuator current.

The specification of the upper and lower current limit results in a current band in which the actuator is operated. The current band results in a characteristic dynamics of the current and current breakdown, in which the information about the operating state of the actuator, in particular its position and temperature, is included. The finding is that this dynamics over the frequency or the period and the duty cycle or the duty cycle (also called duty-cycle or DC), ie the ratio of the duty cycle to the switching period, the output from the two-level control signal can be extracted. The determining means can therefore close the operating state of the actuator from the frequency or period and the duty cycle or the duty cycle of the drive signal.

The determining means has, for example, a so-called capture input, with which it picks up the drive signal from the two-position controller. In such a capture input is an input, for example in a microprocessor, with which the switching times of binary signals can be determined with high accuracy. The activation signal is, in particular, a PWM signal (PWM = pulse width modulation / pulse width modulation).

The determining means may be designed to determine a duty cycle of the drive signal and to determine the temperature of the actuator from the duty cycle. An extra temperature sensor is therefore not required. The thus determined actuator temperature reflects a temperature of the coil of the actuator again. This changes namely their temperature and material dependent their electrical resistance. With the conductor materials commonly used in coils, such as copper, the electrical resistance increases with increasing temperature. To be able to provide a specific, required actuator current under a constant supply voltage, the duty cycle must therefore be adapted to the actuator temperature. Thus, a high actuator temperature requires a comparatively long duty cycle, while a low actuator temperature requires a comparatively short duty cycle in order to provide the same actuator current. So there is a clear relationship between the duty cycle and the actuator temperature. Thus, the actuator temperature can be determined based on the duty cycle or, equivalently, the duty cycle.

The actuator temperature determined by the determination means (11C) can be used to change the electrical power supplied to the actuator. Thus, at a relatively high actuator temperature, the electric power supplied to the actuator can be selectively reduced.

The determining means may also be designed to determine a frequency of the drive signal and the actuator current, as well as to determine a position of the actuator from the frequency and the actuator current. Thus, the actuator position can be determined easily.

Preferably, the determining means is also designed to include a current supply voltage of the actuator in the determination of the operating state. Normally the supply voltage is essentially constant. Then, changes in the supply voltage when determining the operating state need not extra be taken into account. In some cases, however, the supply voltage may fluctuate. Then it is advantageous to consider these in the determination of the operating state.

The determining means preferably has at least one look-up table, a map or another function and is accordingly designed to determine the operating state from the drive signal. In particular, the relation between the switch-on duration and the actuator temperature as well as the relation between actuator position, actuator current and frequency can each be stored in a look-up table or a characteristic field or another function. As a further factor, the dependence on the supply voltage can then be stored in the look-up table or the characteristic field or the other function. The look-up table or the characteristic field or the other function may in particular have been determined empirically beforehand or have been determined in advance on the basis of model calculations.

By using a good electrically conductive material, such as aluminum or copper, in specific areas of the actuator, the dependence of the current build-up dynamics of the actuator on the operating state with respect to the operating state monitoring can be optimized. This is due to the fact that the proposed procedure / device basically evaluates position-dependent eddy current effects within the actuator. In particular, it has therefore proved to be advantageous to provide the armature and / or the magnetic yoke of the actuator with a highly electrically conductive eddy current ring, for example of a copper or aluminum material.

It is also proposed a coupling device with a coupling means for selectively mechanically connecting and disconnecting two components and an electromagnetic actuator for moving the coupling means. The coupling device has the proposed device for operating and for determining the operating state of the actuator. Thus, no extra sensors are needed to determine the operating state of the actuator.

The two components may be, for example, waves. One of the components may be fixed and the other be movable relative thereto, for example rotatable or displaceable. In addition, both components in the non-coupled state relative to each other can be rotatable or displaceable. The coupling means movable by the actuator may be, for example, a coupling sleeve or a clutch disc or a clutch pressure plate.

The coupling device may in particular be a coupling device of a motor vehicle drive train, for example for a passenger or truck. The coupling device can be realized for example in or for a motor vehicle transmission. Such a motor vehicle drive train with such a coupling device is therefore also proposed.

• • Die Hardware-Logik (analoger Zweipunktregler) kann bei schneller Abtastrate in Software realisiert werden (FPGA, DSP, schneller µC).
• • Die Vorgabe der oberen und unteren Stromgrenze kann variiert werden, beispielsweise um die Arbeitsfrequenz in gezielte, vorteilhafte Bereiche zu bringen und/oder konstant dort zu halten.
• • Durch die Vorgabe der Stromgrenzen ist gleichzeitig ein robuster Stromregler implementiert. D. h., der durch die Aktorspule fließende Strom liegt (außer bei sehr schnellen, infolge des praktisch begrenzten Aktorhubs üblicherweise höchstens kurzzeitig auftretenden Bewegungen des Aktors) stets innerhalb des durch den unteren und oberen Grenzwert vorgegeben Toleranzbandes.
• • Durch die Verwendung des analogen Zweipunktreglers ist auch gleichzeitig eine Überstromabschaltung impliziert.
• • Der Aktor kann hinsichtlich seiner Sensitivität optimiert werden, um den Betriebszustand genauer ermitteln zu können. Beispielsweise ist eine hierauf gezielte modellbasierte Entwicklung des Aktors über FEM-Simulation möglich.
• • Die ermittelten Betriebszustände des Aktors können mit erwarteten Betriebszuständen bzw. Intervallen tolerierbarer Betriebszustände verglichen werden. Auf diese Weise ist bspw. eine Überwachung des Aktors auf Fehlfunktionen bzw. auf Verschleiß möglich (Diagnose bzw. Condition Monitoring).
• • Die ermittelte Aktortemperatur kann dazu genutzt werden, den Aktor vor Auftreten einer Überhitzung abzuschalten.
• • Vor Erreichen der Überhitzung kann die in den Aktor eingebrachte elektrische Leistung sukzessive reduziert und so ein Weiterbetrieb mit verringerter Leistung ermöglicht werden, um eine Überhitzung zu verhindern (sogenannte Derating-Funktion).

The proposed device may, in addition to those already mentioned have the following modifications or advantages:

• • The hardware logic (analogue two-point controller) can be implemented in software at a fast sampling rate (FPGA, DSP, fast μC).
• • The specification of the upper and lower current limit can be varied, for example, to bring the working frequency in targeted, advantageous areas and / or to keep constant there.
• • By specifying the current limits, a robust current controller is implemented at the same time. In other words, the current flowing through the actuator coil is always within the tolerance band specified by the lower and upper limit (except in the case of very fast movements of the actuator, which usually occur at most only briefly due to the practically limited actuator stroke).
• • Using the analog two-point controller also implies an overcurrent shutdown.
• • The actuator can be optimized with regard to its sensitivity in order to be able to determine the operating status more precisely. For example, a targeted model-based development of the actuator via FEM simulation is possible.
• • The determined operating states of the actuator can be compared with expected operating states or intervals of tolerable operating states. In this way, it is possible, for example, to monitor the actuator for malfunctions or wear (diagnosis or condition monitoring).
• • The determined actuator temperature can be used to switch off the actuator before overheating occurs.
• • Before overheating is reached, the electrical power supplied to the actuator can be successively reduced, thus enabling further operation with reduced power in order to prevent overheating (so-called derating function).

• 1 ein elektromagnetischer Aktor mit einer Kupplungsvorrichtung,
• 2 ein System zum Betreiben eines elektromagnetischen Aktors,
• 3 ein Kennfeld zur Bestimmung einer Aktorposition,
• 4 ein weiteres Kennfeld.

In the following the invention will be explained in more detail with reference to figures, from which further preferred embodiments and features of the invention are removable. In each case show in a schematic representation:

• 1 an electromagnetic actuator with a coupling device,
• 2 a system for operating an electromagnetic actuator,
• 3 a map for determining an actuator position,
• 4 another map.

The electromagnetic actuator 1 according to 1 used to move a coupling agent 7 in a coupling device 2 , The actor 1 exemplifies a single solenoid 3 on and a linearly movable anchor 4 , At the actor 1 So it is a linear actuator. The mobility of the anchor 4 is illustrated by the double arrow. By electrical energization of the coil 3 can be a magnetic force on the anchor 4 be exercised, which the anchor 4 in the direction of the coil 3 urges. A restoring force acting against the magnetic force can be applied, for example, by a spring means. Depending on the height of the magnetic force and the restoring force then results in the position of the armature 4 in the actor 1 ,

Stationary on the anchor 4 Optionally a eddy current ring 5 be arranged. This consists of an electrically conductive material, for example of a copper or aluminum material.

The sink 3 is stationary in a housing 6 arranged. The anchor 4 is in the case 6 guided at least linearly movable. The anchor 4 acts on the coupling agent 7 , which is exemplified here as a coupling sleeve. At least the linear movement of the anchor 4 is thus on the coupling agent 7 transfer. The coupling agent 7 So it's with the anchor 4 moved linearly. It can be a rotation decoupling between anchor 4 and coupling agents 7 be provided, which prevents rotation of the coupling means 7 on the anchor 4 is transmitted.

The coupling agent 7 is designed to have two components 8th . 9 Optionally connect and disconnect mechanical. In a first position of the coupling agent 7 are the components 8th . 9 therefore mechanically coupled to each other and in a second position of the coupling means 7 are the components 8th . 9 therefore separated from each other mechanically. The components 8th . 9 In the present case, by way of example, shafts are rotatable relative to one another in the separated state and, in the coupled state, can only be rotated together. For this they are in the housing 6 by appropriate storage means 10 , For example, bearings, rotatably mounted. A rotation axis of the components 8th . 9 is with the reference numeral L characterized.

In the 1 shown coupling device 2 Preferably used in a motor vehicle drive train, such as a motor vehicle transmission, for optional mechanical connection and separation of two waves. The housing 6 can then be a transmission housing, for example.

The position of the anchor 4 in the actor 1 (= Actuator position) directly determines the position of the coupling means 7 , So also the coupling state of the coupling device 2 , In order to determine which actuator position is currently present, extra sensors can be used. Likewise, external sensors can be used to determine the actuator temperature. As already mentioned, however, there are disadvantages here. It is therefore desirable that the operating state of the actuator 1 in particular to be able to determine its actuator position and its actuator temperature on the basis of existing means.

2 shows a system for operating an electromagnetic actuator 1 , in particular that of 1 , The system has a microcontroller 11 , In addition, an analog two-point controller 12 provided, as well as a bridge driver 13 , Furthermore, a bridge circuit 14 intended. This serves for electrical energization of the actuator 1 , The actor 1 is in 2 as an electrical equivalent circuit diagram, consisting of a network of resistive resistors and inductors shown. The Elements 11 . 12 . 13 . 14 of the system have corresponding inputs and outputs, each in 2 are shown and designated.

The microcontroller 11 has two modules by way of example 11A . 11B on. These can be designed, for example, as software modules or hardware modules. module 11A In this case contains a superimposed control logic. module 11A So contains, for example, control functions, such as in particular a functional software. module 11B contains a target current determination, which has a current regulator, an Iststromaufbereitung and a means of investigation 11C for determining the operating state of the actuator 1 , module 11B So for example contains basic functions, such as in particular a basic software.

The electrical current underlying the desired current determination, the current controller and the actual current conditioning forms the actuator current, ie the actuator 1 through the bridge circuit 14 supplied electric power. By means of the setpoint current determination with current controller becomes a required electric current for the actuator 1 (Setpoint current, setpoint actuator current) determined. By means of the Iststromaufbereitung becomes a current the actor 1 supplied electric current (actual current, actual actuator current) for processing in the microcontroller 11 prepared and the desired current determination with current regulator and the investigative means 11C made available.

The nominal current determination with current controller transfers corresponding control signals, in 2 referred to as "PWM Out 1", "PWM Out 2", to the analog two-point controller 12 , The two-position controller consists of a comparator circuit 12A and an RS flip-flop 12B , The two-position controller 12 is here constructed as a discrete hardware circuit. Alternatively, assuming a sufficiently fast sampling rate, it can also be used as a software module, in particular of the microcontroller 11 be trained.

The two-position controller 12 leaves the actuator current with the help of the comparator circuit 12A and the RS flip-flop 12B Toggle between defined current limits, that is, fluctuate. These current limits, in detail a lower and an upper current limit, are provided by the microcontroller 11 specified. In the two-position controller 12 the current actuator current (actual actuator current) is compared with the specified current limits. For this purpose, the current actuator current is the two-position controller 12 fed. If the upper limit is exceeded, the current is removed from the actuator (= current off). If the lower limit is reached, the actuator is energized (= current on). The signal for the supply and Entstromung of the actuator is used as drive signals H1 . H2 from the two-position controller 12 to the bridge driver 13 output. By specifying the current limits thus simultaneously a current controller and an overcurrent shutdown are realized.

The bridge driver 13 operates the bridge circuit 14 , By means of this the actor becomes 1 according to the drive signals H1 . H2 electrically energized. In this case, the actuator 1 by momentarily applying a supply voltage temporarily energized (= power on) and temporarily de-energized (= power off). In the present case, the bridge circuit is formed by way of example as an H-bridge circuit. Accordingly, the bridge driver has 13 via a driver per bridge branch. These drivers are in 2 referred to as "H1 driver" and "H2 driver".

In the area of the bridge circuit 14 In addition, means are provided by which the currently applied actuator current (actual actuator current) and the currently applied supply voltage of the actuator 1 measured or otherwise determined. In 2 These means are referred to as "current measurement" and "measurement voltage". The current actuator current is among others the two-position controller 12 in detail of the comparator circuit 12A supplied, so that the actuator current, as described above, is held between the predetermined current limits.

The specification of the upper and lower current limit results in a predetermined current band, in which the actuator current resides, in which he actuator is thus operated. With such a predetermined current band results in a characteristic dynamics of current and current reduction. In 2 For example, such an upstream and downstream degradation is within the block of the comparator circuit 12A shown.

The information about the operating state of the actuator 1 , in particular the actuator position and the actuator temperature, is implicitly contained in this dynamic. This dynamic is due to the special control characteristics of the two-position controller 12 also in its control signals H1 . H2 again. So you can from the frequency and duty cycle of the drive signals H1 . H2 be extracted. The microcontroller 11 Therefore, at least one of the drive signals H1 . H2 fed via a capture input. In 2 this is the drive signal H1 , The capture input is in 2 referred to as "PWM-In 1". The tap for the drive signal H1 is exemplified at the respective output of the RS flip-flop 12B or the two-point controller 12 (in 2 at its upper outlet).

The drive signal H1 is via the capture input of the microcontroller 11 the investigative agent 11C fed. It also becomes the investigative tool 11C via another input of the microcontroller 11 (in 2 referred to as "ADC-In 2") supplied to the currently applied supply voltage. As explained above, the investigative tool receives 11C also from the actual current conditioning of the module 11B the current electrical current supplied to the actuator (actual actuator current).

For determining the operating state based on the incoming information / signals, the investigative means 11C one or more maps on. It is designed to determine the operating state of the actuator so.

Examples of such maps are 3 and 4 removable as an example. These may have been determined empirically in advance, for example.

3 shows a map, by means of which the determination means 11C based on the actuator current ("current, A") and the frequency of the drive signal H1 ("Frequency, Hz") can determine the actuator position ("Position, mm"). Hereby, exactly one actuator position can be uniquely assigned to each value pair of current and frequency.

Different supply voltages can result in different assignments of current, frequency and actuator position. Therefore, if the supply voltage is substantially constant, it need not be further included in the determination of the operating state. However, if this varies, it may be necessary to provide a plurality of such maps for different supply voltages or supply voltage range.

4 shows several maps for different supply voltages (between 36V and 56V), by which the investigative means 11C based on the actuator current ("current, A") and the duty cycle of the drive signal H1 ("DutyCyle,%") can determine the actuator position ("Position, mm"). With a supply voltage between 36V and 56V, exactly one actuator position can be uniquely assigned to each value pair of current and duty cycle. The top map in 2 forms that for the supply voltage in the range of 36V and the lowest map in 2 forms that for the supply voltage in the range of 56V.

Corresponding maps may alternatively or additionally be provided for the actuator temperature, which results in particular from the duty cycle and the supply voltage. Such a map represents the clear relationship between the actuator temperature and the duty cycle.

In the system according to 2 In addition to the explicitly described or named components, optional filters may be used 15 be provided. The Elements 16 each provide an optional signal conditioning for the two-position controller 12 represents.

LIST OF REFERENCE NUMBERS

1

Electromagnetic actuator

2

coupling device

3

solenoid

4

anchor

5

Eddy-current ring

6

casing

7

Coupling agent, coupling sleeve

8th

Component, shaft

9

Component, shaft

10

bearing means

11

microcontroller

11A, 11B

module

11C

determining means

12

Analog two-point controller

12A

comparator circuit

12B

RS flip-flop

13

bridge drivers

14

bridge circuit

15

filter

16

signal conditioning

H1, H2

control signal

L

axis of rotation

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

• DE 102005018012 A1 [0004]
• DE 102007034768 B3 [0004]

Claims (10)

Device for operating and determining an operating state, in particular an actuator temperature and / or an actuator position, of an electromagnetic actuator (1), in particular of a linear actuator, characterized by a two-point controller (12) for operating the actuator (1) and a determination means (11C), which is designed to determine a time profile of the control signal (H1) output by the two-point controller (12) and to determine the operating state therefrom. Device after Claim 1 , wherein the two-position controller (12) is an analog two-point controller. Device after Claim 2 , wherein the two-position controller (12) is constructed discretely in hardware. Device according to one of the preceding claims, wherein the two-point controller (12) an upper current limit and a lower current limit are predetermined by which he limits the actuator (1) supplied electric current. Device according to one of the preceding claims, wherein the determining means (11C) is adapted to determine one of duty cycle and duty cycle of the drive signal (H1) and to determine from the one of duty cycle and duty cycle an actuator temperature. Device according to one of the preceding claims, wherein the determining means (11C) is adapted to determine one of the frequency and period of the drive signal (H1) and to determine the electrical current supplied to the actuator (1) and from one of the frequency and period duration as well to determine the current an actuator position (1). Device according to one of the preceding claims, wherein the determining means (11C) is adapted to include a supply voltage of the actuator (1) in the determination of the operating state. Device according to one of the preceding claims, wherein the determining means (11C) has a lookup table or a map or other mathematical function and is adapted to determine the operating state of the actuator (1) hereby and with the drive signal (H1). Coupling device (2) with a coupling means (7) for selectively mechanically connecting and disconnecting two components (8, 9) and an electromagnetic actuator (1) for moving the coupling means (7), characterized by a device for operating and for determining an operating state of the Actuator (1) according to one of the preceding claims. Motor vehicle drive train, characterized by a coupling device (2) according to Claim 9 ,

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