Device and method for determining switching times of an electromagnetic actuator, computer program

Abstract

Control device (10) for determining switching times of an electromagnetic actuator (1), comprising: - a first process module (11) designed to determine a course of a concatenated magnetic flux as a function of a current intensity for controlling the electromagnetic actuator (1) as an actual characteristic curve (200); - a second process module (12) designed to provide at least one reference characteristic curve (300) for the magnetic flux as a function of the current intensity for controlling the electromagnetic actuator (1), wherein the reference characteristic curve (300) has a first characteristic curve section (301), wherein the first characteristic curve section (301) has a linear profile with a defined gradient and a negative offset (320), wherein the negative offset (320) is selected such that during a switching operation in which the electromagnetic actuator (1) is not moved, the first characteristic curve section (301) of the reference characteristic curve (300) is not exceeded, and wherein the slope of the first characteristic curve section (301) corresponds to a slope of the actual characteristic curve at the beginning of switching off the electromagnetic actuator (1), wherein the reference characteristic curve (300) has a second characteristic curve section (302) whose gradient corresponds to the actual characteristic curve at the beginning of switching on the electromagnetic actuator (1) and which includes a positive offset, and wherein the switching off begins with switching off the power supply of the electromagnetic actuator (1); and - a third process module (13) designed to determine a switching time of the electromagnetic actuator (1) using a comparison of values ​​of the actual characteristic curve (200) with values ​​of the at least one reference characteristic curve (300).

Description

[0001] The present invention relates to a control device and a method for determining switching times, in particular for determining switching times of an electromagnetic actuator. The present invention further relates to a device for implementing the method and a computer program.

[0002] Solenoid valves, for example, can be used for the automated dosing of liquid or gaseous substances. The respective substance can be supplied to such a valve under pressure. The quantity of the respective substance to be dosed can then be dosed according to the period of time the valve is open. For particularly small dosing quantities, either relatively low pressures, small valve dimensions, or very short opening intervals are used. Therefore, precise control of the switching times of such a valve is of great importance.

[0003] DE 10 2009 042 777 A1 describes a method for determining the armature position of an electromagnetic actuator by measuring current and magnetic field and comparing the measured values ​​with stored characteristic curves. In particular, sensor detection of the magnetic field is used to enable the position of the armature to be determined during operation.

[0004] DE 10 2017 125 005 B3 describes a method for the model-based determination and evaluation of the functional states of a sensorless electromagnetic actuator. By measuring current and voltage and comparing them with modeled characteristic curves, which are created using hysteresis models, monitoring is possible without separate sensors.

[0005] DE 10 2011 075 935 B4 describes a method for determining fault conditions in an electromagnetic actuator. A sensorless diagnosis is performed based on a comparison between a magnetic reference characteristic and an actual characteristic derived from current and voltage measurements. Individual properties of the actuator are integrated into the reference characteristic.

[0006] DE 10 2012 000 766 A1 describes a control and detection arrangement for controlling and monitoring a magnetic actuator, in which a controlled variable is determined from measured variables such as current and voltage using a stored characteristic field.

[0007] DE 10 2018 112 579 A1 describes a method for determining the wear of a solenoid valve with a coated armature surface. The method involves measuring the interlinked magnetic flux versus the current during armature travel and comparing it with a Psi-I reference curve. Deviations from this reference serve as indicators of increasing wear of the armature coating.

[0008] The switching behavior of solenoid valves used to meter fluids can depend on several external influences. For example, the switching behavior can change depending on the valve's orientation or parameters such as pressure and temperature.

[0009] In some conventional approaches, it is therefore necessary to operate the dosing valves under as constant operating conditions as possible in order to minimize variations in the switching behavior during dosing.

[0010] Alternatively, it is possible to monitor the valve's switching behavior and, if changes occur in the switching behavior, adjust the switching times for controlling the valve to turn it on and off depending on the monitored switching behavior. For sufficiently long switching times, such monitoring of the switching behavior can be based, for example, on the electrical current used to control the valve.

[0011] For relatively short switching times, such as those required for dosing relatively small quantities in the life science sector, such monitoring of the switching times based solely on the electrical current used to control the valve is no longer possible.

[0012] There is therefore a need for a method for determining switching times for an electromagnetic actuator, such as a solenoid valve, that can also be used for very short switching times. The present invention is therefore based on the object of providing a control device and a method for determining switching times of an electromagnetic actuator, a device, and an electronic computer program that can also be used for very short switching times.

[0013] This object is achieved by the control device, the method for determining switching times, the device for implementing this method, and a computer program according to the independent patent claims. Further advantageous embodiments are the subject of the dependent patent claims.

[0014] According to a first aspect, the present invention relates to a control device for determining switching times of an electromagnetic actuator. The control device comprises a first process module, a second process module, and a third process module. The first process module is configured to determine a profile of a concatenated magnetic flux as a function of a current intensity for controlling the electromagnetic actuator. This profile can be provided as an actual characteristic curve. The second process module is configured to provide at least one reference characteristic curve for the magnetic flux. The reference characteristic curve can specify the magnetic flux as a function of the current intensity for controlling the electromagnetic actuator. The reference characteristic curve can comprise multiple sections.In particular, the reference characteristic curve can have a first characteristic curve section characterized by a linear profile with a defined gradient and a defined offset, in particular a negative offset. The negative offset can be selected such that the first characteristic curve section of the reference characteristic curve is not exceeded during a switching operation in which the electromagnetic actuator is not moving. Alternatively or cumulatively, the gradient of the first characteristic curve section can correspond to the gradient of the actual characteristic curve at the beginning of the switching off of the electromagnetic actuator. In this case, the switching off of the electromagnetic actuator begins with the switching off of the power supply to this electromagnetic actuator. The third process module is designed to determine a switching time of the electromagnetic actuator.The switching time can be determined by comparing values ​​of the actual characteristic curve with the values ​​of at least one reference characteristic curve.

[0015] According to a second aspect, the present invention relates to a method for determining switching times of an electromagnetic actuator. The method comprises providing at least one reference characteristic curve that specifies a magnetic flux as a function of a current intensity for controlling the electromagnetic actuator. The reference characteristic curve can comprise multiple sections. In particular, the reference characteristic curve can have a first characteristic curve section characterized by a linear profile with a defined gradient and a defined offset, in particular a negative offset. The negative offset can be selected such that the first characteristic section of the reference characteristic curve is not exceeded during a switching operation in which the electromagnetic actuator does not move.Furthermore, the slope of the first characteristic curve section can correspond to the slope of the actual characteristic curve at the beginning of the switching off of the electromagnetic actuator. The switching off of the electromagnetic actuator begins with the switching off of the voltage supply to this electromagnetic actuator. The method further comprises switching the electromagnetic actuator, determining a profile of the interlinked magnetic flux as a function of a current intensity during the control of the electromagnetic actuator as an actual characteristic curve, comparing the values ​​of the actual characteristic curve with the values ​​of the reference characteristic curve, and determining a switching time of the electromagnetic actuator using the comparison of the values ​​of the actual characteristic curve with the values ​​of the reference characteristic curve.

[0016] Alternatively or additionally, determining a switching time may include determining a switch-on time and a switch-off time. Optionally, it may further include determining a switching duration between the determined switch-on time and the determined switch-off time, as well as adjusting a time interval between switching on and off the electromagnetic actuator for a subsequent switching operation using the determined switching duration between the determined switch-on time and the determined switch-off time.

[0017] According to a further aspect, the present invention relates to a device for carrying out a method for determining switching times of an electromagnetic actuator according to the second aspect. The device comprises an electromagnetic actuator having a coil for generating a magnetic field and a movable armature. Furthermore, the device comprises at least one measuring device for measuring a current intensity and a voltage in the circuit generating the magnetic field. In addition, the device comprises at least one memory unit and a processing unit. The memory unit comprises a control device for storing reference characteristic curves. By means of the processing unit, values ​​of the actual characteristic curve and the reference characteristic curve can be compared with one another. A switching time is determined by comparing the values ​​of the determined actual characteristic curve with the values ​​of the reference characteristic curve.

[0018] According to a further aspect, the present invention relates to a computer program that can be loaded into a memory unit of a control device according to the first aspect. This computer program contains program code sections that cause the control device to execute the method for determining switching times of an electromagnetic actuator according to the second aspect when the computer program is executed in the control device.

[0019] The present invention is based on the finding that the switching properties of an electromagnetic actuator, such as those used in solenoid valves, can change depending on various external parameters such as pressure and temperature. This particularly affects the actuator's control behavior, since the time period between actuating the actuator and the resulting response can vary depending on these external parameters. In particular, switching delays can occur in which a control signal for controlling the actuator deviates from the actual switching time.

[0020] If such an electromagnetic actuator is used in a solenoid valve, for example, the time period during which the valve is actually open can vary despite identical time intervals between the actuation of the valve opening and closing. These variations depend on external parameters such as temperature and pressure. To compensate for such variations, the switching behavior of the electromagnetic actuator can be monitored. For sufficiently long switching times, i.e., periods between switching the actuator on and off, the switching times can be determined by evaluating the electrical current curve used to control the actuator.

[0021] Furthermore, the present invention recognizes that such a determination of the switching times by evaluating the electrical current curve is no longer possible for very short switching times, since the actuator is no longer fully switched during such short periods. In these cases, switching off can already occur before the actuator has reached its end position after switching on.

[0022] Based on this finding, the present invention creates a way to determine switching times for an electromagnetic actuator, making it possible to precisely determine the switching times of the electromagnetic actuator even with very short switching times. Based on the switching times determined in this way, it is possible to monitor the switching behavior of an electromagnetic actuator. This monitoring enables the control of the electromagnetic actuator to be adapted so that variations in the switching behavior, such as those caused by external influences such as temperature or pressure, can be compensated for. This achieves a high level of precision in the switching behavior, even with very short switching times, such as those required for dosing small quantities of a fluid using a solenoid valve.

[0023] An electromagnetic actuator within the meaning of the present invention can be an actuator with at least one movable armature and at least one coil. By applying an electric current, the coil can generate a magnetic field that exerts a force on the armature and moves it from a first position to a second position. The electromagnetic actuator is switched on, for example, by applying an electric current to the coil. To switch it off, the current flow through the coil is interrupted, whereupon the armature is moved back to the first position, for example by a spring force or another return mechanism. Alternatively, the armature can be returned by applying an electric current to another coil.

[0024] The first, second, and third process modules can be any suitable hardware components, each configured for the specified functions. Alternatively, multiple hardware components can be provided to implement the process modules and communicate with each other. Processors, particularly microcontrollers, and / or memory, for example, can be used to implement the required functionality. The process modules can communicate with each other and with external components to perform their tasks. Software code provided in a memory can instruct processors to implement the required functions.

[0025] To determine the actual characteristic curves, i.e., the course of the interlinked magnetic flux as a function of the current, interfaces can be provided in the first process module that record the required measured values, such as electrical voltage and current at the coil of the electromagnetic actuator. If these measured values ​​are available as analog signals, suitable analog-to-digital converters (A / D converters) can be provided for converting them into digital signals.

[0026] It is also possible to implement several process modules, especially all three, in a common processing device. The functions of the individual process modules can be implemented in the form of suitable software modules or similar. Processing takes place at a sufficiently high speed so that the determined switching times can be precisely determined and provided in time to enable the subsequent process steps.

[0027] The reference characteristic curve for the magnetic flux as a function of the current strength for controlling the electromagnetic actuator can be provided in various ways. One possibility is to provide the reference characteristic curve in the form of individual discrete support points, i.e. as points in a diagram that represents the magnetic flux versus the electrical current strength. This can be done, for example, in the form of a lookup table. Other data structures for storing the corresponding information are also possible. Alternatively, the reference characteristic curve can be described functionally. This can be done using a single function or by multiple functions, each of which represents different sections of the reference characteristic curve. For example, the reference characteristic curve can be described by one or more straight lines defined by gradient and offset.

[0028] The interlinked magnetic flux (Ψ) refers to the total magnetic flux of a coil in an electromagnetic actuator. This results from the integration of the magnetic flux density over an area formed by the coil and its leads. The interlinked magnetic flux is usually determined by the product of the number of turns of the coil and the magnetic flux through a single turn or cross-sectional area of ​​the coil. The interlinked magnetic flux can be calculated - for example, by the first process module - using current and voltage measurements on the coil. The current curve, the voltage curve, and the electrical resistance of the coil can be used to calculate the interlinked magnetic flux. The induced voltage curve can be calculated from the voltage curve. The interlinked magnetic flux can be determined by integrating the induced voltage curve.

[0029] Alternatively or additionally, the values ​​of the actual characteristic curve can correspond to predefined armature positions of a movable armature of the electromagnetic actuator. In this way, it is possible to derive the position of the movable armature from the values ​​and thus infer the current state of the electromagnetic actuator. For example, the armature positions can be used to determine when a valve operated with such an actuator begins to open or close.

[0030] Alternatively or additionally, the interlinked magnetic flux can be determined from a current and voltage measurement in the magnetic field generating circuit during operation of the electromagnetic actuator. For this purpose, suitable sensors for current and voltage measurement can be provided on the coil or in the circuit that feeds the coil. The sensors can, for example, be directly equipped with suitable analog-to-digital converters to provide digital values ​​for current and voltage. Alternatively, it is possible to provide analog sensor signals that are digitized during downstream processing, for example in the first process module. In addition to the determined values ​​for current and voltage in the magnetic field generating circuit, such as a coil, other parameters, such as the internal resistance of the coil, can also be used to determine the interlinked magnetic flux.The internal resistance of the coil can also be determined by measuring current and voltage.

[0031] Alternatively or additionally, the determined switching times can include switching on and / or off the electromagnetic actuator. For example, the switching time for switching on the electromagnetic actuator can be defined as the time at which the armature of the actuator begins to move from the rest position. Analogously, the switching time for switching off can be considered to be the moment at which the armature reacts to a corresponding control of the actuator. Such a control for switching off the actuator can, for example, be the switching off of a control signal for the circuit generating the magnetic field, such as a coil. Switching times, i.e. time periods for active and / or passive phases of the actuator, as well as switching delays can be derived from the switching times for switching on and / or off the electromagnetic actuator determined in this way.

[0032] Alternatively or additionally, a type-specific and / or batch-specific reference characteristic can be provided and / or processed using the reference characteristic curve. In other words, the reference characteristic curve only needs to be determined once for multiple electromagnetic actuators of the same type and / or batch. This significantly reduces the effort required to determine the reference characteristic curve.

[0033] Alternatively or additionally, the reference characteristic curve can be adapted and / or trained to an actual characteristic curve using a machine learning model. Such automatic adaptation of the reference characteristic curve makes it possible to individually adjust the reference characteristic curve to the respective electromagnetic actuator based on its actual characteristic curve.

[0034] The reference characteristic curve also has a second characteristic curve segment. The gradient of this segment of the actual characteristic curve can correspond to the gradient at the beginning of the switching-on process, i.e., the application of voltage, of the electromagnetic actuator. Furthermore, this second characteristic curve segment can contain a positive offset. In this way, analogous to the first characteristic curve segment, the switching-on behavior of the electromagnetic actuator can also be easily characterized.

[0035] Alternatively or additionally, the positive offset can be dimensioned such that the value of the reference characteristic curve lies within a specified interval during a switch-off process. This allows the reference characteristic curve to be adjusted to the switch-off behavior of the electromagnetic actuator, similar to the switch-on process.

[0036] According to one embodiment, the electromagnetic actuator can be a metering switching valve. Furthermore, any other suitable valves or valve arrangements with an electromagnetic actuator can be used. Using the inventive concept for determining the switching times, precise control of the valves and thus exact metering of a fluid can be achieved even with very short switching durations or switching intervals.

[0037] Alternatively or additionally, determining a switching time can include determining a switch-on time and a switch-off time. In addition, a switching duration between the determined switch-on time and the determined switch-off time can be determined. Based on this switching duration, for example, a time period between switching on and off the electromagnetic actuator can be adjusted for a subsequent switching process. By dynamically adjusting the switching processes based on the determined switch-on and switch-off times, variations in switching behavior can be compensated for. Changes in switching behavior, which arise, for example, from temperature or pressure fluctuations, can thus be quickly detected and compensated. This significantly increases the precision of the switching behavior of the electromagnetic actuator.

[0038] The previously described embodiments and further developments can be combined with each other, where appropriate. Features of the method claims can be implemented and / or executed by corresponding components of the control device, thereby supplementing or expanding its functionality. This enables a person skilled in the art to apply aspects of the method claims to the control device as well. Short description of the characters

[0039] The detailed description of the figures explains non-limiting embodiments, their features, and other advantages based on the drawings. These show: Fig. 1: a schematic representation of a control device for determining switching times of an electromagnetic actuator according to an embodiment; Fig. 2: a diagram of the chained magnetic flux as a function of the current; Fig. 3: a schematic representation of a method for determining switching times of an electromagnetic actuator according to an embodiment; Fig. 4: a schematic representation of a device for operating an electromagnetic actuator according to an embodiment.

[0040] The accompanying drawings are intended to provide a better understanding of embodiments of the invention. They illustrate the embodiments and, in conjunction with the description, serve to explain the principles and concepts of the invention. The elements of the drawings are not necessarily drawn to scale.

[0041] In the figures of the drawings, identical, functionally identical and acting elements, features and components are provided with the same reference symbols, unless otherwise stated. Detailed description of the invention

[0042] Fig. 1 shows a schematic representation of a block diagram of a control device 10 according to one embodiment. The control device 10 is provided for determining switching times of an electromagnetic actuator 1. The electromagnetic actuator 1 can, in principle, be any electromagnetic actuator. For example, the electromagnetic actuator can comprise a movable armature and a unit for generating a magnetic field, such as a coil. By generating a magnetic field, the movable armature can be deflected. If the magnetic field is switched off, the armature can return to its initial position, for example, due to a spring force.

[0043] The control device 10 comprises three process modules 11, 12, 13, which can be implemented both as separate units and as elements of a common unit. For example, the process modules 11, 12, 13 can be implemented at least partially in the form of software code in a microcontroller system or the like.

[0044] The first process module 11 determines a profile of a concatenated magnetic flux in the electromagnetic actuator 1 as a function of a current strength for controlling the electromagnetic actuator. The determined profile of the concatenated magnetic flux as a function of the current strength is then provided as an actual characteristic curve. To determine this profile, an electrical voltage and an electrical current strength for exciting a coil in the electromagnetic actuator 1 can be recorded and transmitted to the first process module 11. For this purpose, the first process module 11 can comprise one or more suitable interfaces to receive the corresponding values, such as current and voltage. If the values ​​are provided as analog signals, suitable analog-to-digital converters can be provided in the first process module 11 to convert analog sensor signals into corresponding digital values.Alternatively, the provided sensors can directly perform an analog-to-digital conversion and provide digital sensor values ​​to the first process module 11.

[0045] The second process module 12 provides at least one reference characteristic curve for the magnetic flux as a function of the current intensity for controlling the electromagnetic actuator 1. This reference characteristic curve can be defined in different ways. For example, it can be specified by several discrete points provided in tabular form, such as a lookup table. Alternatively, it is possible to define the reference characteristic curve as a mathematical description, such as a parameterizable formula. For example, the reference characteristic curve can be characterized as a straight line with a specified gradient and an offset. Different gradients and offsets can also be specified for different sections of the reference characteristic curve. Furthermore, other forms for characterizing the reference characteristic curve are conceivable.The corresponding data can be stored in a suitable, in particular non-volatile, memory of the second process module 12.

[0046] The reference characteristic curve can be determined once during production or initialization of the electromagnetic actuator 1 and stored in the second process module 12. Alternatively, it is possible to determine uniform reference characteristics for a batch or an entire type of electromagnetic actuators and store them in the respective control devices.

[0047] The third process module 13 is connected to the first process module 11 and the second process module 12 and receives their data. It compares the actual characteristic curve of the first process module 11 with the reference characteristic curve of the second process module 12 and derives a switching time of the electromagnetic actuator 1 from this. This switching time is determined when the actual characteristic curve intersects the reference characteristic curve. If an exact intersection point cannot be determined due to discrete values, the switching time can be determined based on the change in the position of the actual characteristic curve relative to the reference characteristic curve.

[0048] Fig. Figure 2 shows a diagram illustrating the relationship between electric current I and interlinked magnetic flux Psi for different switching times of an electromagnetic actuator 1.

[0049] The curve 100 represents the curve for a relatively long switching time. For example, a long switching time is defined as a switching time in which the actuator 1 is fully deflected after being switched on before the actuator 1 is switched off. Accordingly, a short switching time is characterized by the actuator 1 being switched off before the actuator is fully deflected.

[0050] The curve 100 for a long switching time has four significant points. When switched on, i.e. when an electrical voltage or current is applied, both the current and the interlinked magnetic flux (Psi) both start at zero. The current then increases. Between approximately 0.5 and 0.6 amperes, the actuator begins to move because the magnetic field overcomes the spring force of the return element. During the movement, position 101 is passed through. This position is easily detectable, but does not mark the beginning of the movement of actuator 1. At position 102, actuator 1 is fully deflected. When switched off, i.e. when the supply voltage or current is disconnected, the current and interlinked magnetic flux fall from their respective maximums. Position 111 is passed through during the movement before the actuator returns to the rest position at position 112.

[0051] This curve 100 describes a hysteresis curve from which the switching time of the actuator 1 can be determined by the time difference between position 102 and position 112.

[0052] Curve 200 describes a switching process for a short switching time. Since actuator 1 is switched off before the actuator is fully deflected, positions 101 and 102 do not occur in this case and are therefore not available for determining the switching time.

[0053] To determine the switching times for short switching durations, curve 200, which represents the actual characteristic curve, is compared with a reference characteristic curve 300. Curve 200 corresponds to the actual characteristic curve determined by the first process module 11. Reference characteristic curve 300 corresponds to the reference characteristic curve provided by the second process module 12.

[0054] The switching points are identified as the positions at which the actual characteristic curve, according to curve 200, intersects the reference characteristic curve 300. If an exact intersection point cannot be determined, it is sufficient to determine a point in time at which the value of the actual characteristic curve moves from one side of the reference characteristic curve to the opposite side. For example, a switch-on point can be defined as the point in time at which curve 200 changes from an area to the right below the reference characteristic curve 300 to the area to the left above the reference characteristic curve 300.

[0055] Analogously, a switch-off time is determined when the curve 200 of the actual characteristic intersects the reference characteristic 300 in the opposite direction.

[0056] In the Fig. In the diagram shown in Figure 2, the reference characteristic curve 300 is formed by two characteristic curve sections 301 and 302. These sections can consist of the corresponding sections of two straight lines, each characterized by its gradient and an offset. At the intersection point of these two straight lines, the first section 301 of the reference characteristic curve 300 merges into the second section 302 of the reference characteristic curve 300.

[0057] The first section 301 of the reference characteristic curve 300 can have a gradient that corresponds to the gradient of an actual characteristic curve for the actuator 1 at the beginning of the switching off of the electromagnetic actuator 1. For this first section 301 of the reference characteristic curve 300, a negative offset 320 can be selected, which ensures that during a switching operation in which the electromagnetic actuator 1 is not moved, this section 301 of the reference characteristic curve 300 is not exceeded.

[0058] The second section 302 of the reference characteristic curve 300 can have a gradient that corresponds to the gradient of an actual characteristic curve for the actuator 1 at the beginning of switching on. A positive offset can be selected for this second section 302 of the reference characteristic curve 300 so that it is not exceeded too early during the switching on of the actuator 1. As a result, the second section 302 of the reference characteristic curve 300 can be shifted, for example, to a range between positions 111 and 112.

[0059] Depending on the application, alternative reference curves 300 can also be defined for determining the switching times. For example, a reference curve can be adapted to an actual curve using a machine learning model.

[0060] Fig. 3 shows a flowchart for a method V for determining switching times of an electromagnetic actuator 1 according to one embodiment. Method V comprises several method steps S1 to S4, but may also include additional steps depending on the implementation.

[0061] In step S1, at least one reference characteristic curve is provided which specifies the magnetic flux as a function of the current intensity for controlling the electromagnetic actuator 1.

[0062] In step S2, the switching of the electromagnetic actuator 1 takes place, which comprises at least one switching-on process and one switching-off process.

[0063] In step S3, the course of the interlinked magnetic flux is determined as a function of the current intensity during the control of the electromagnetic actuator 1. This course is provided as an actual characteristic curve.

[0064] In step S4, the values ​​of the actual characteristic curve are compared with those of the reference characteristic curve. Based on this comparison, a switching time for electromagnetic actuator 1 is determined.

[0065] The determined switching times for the electromagnetic actuator 1 can be a switch-on time and a switch-off time. A switching duration can be calculated from a determined switch-on time and the corresponding switch-off time. This duration results from the time span between the switch-on time and the switch-off time. For applications such as the precise dosing of a fluid using a solenoid valve, it may be necessary to strictly adhere to a specified switching duration in order to ensure precise dosing. If the determined switching duration deviates from the specified switching duration, the control of the electromagnetic actuator can be adjusted accordingly for subsequent switching operations. Both the switch-on time and the switch-off time can be modified based on the determined deviations.

[0066] In this way, potential deviations that occur during operation can be quickly detected and compensated for. In particular, external influences such as temperature fluctuations or pressure changes can be effectively compensated to ensure high precision in the actuator's switching behavior.

[0067] Fig. Figure 4 shows a schematic representation of a device 20 for operating an electromagnetic actuator 1 according to one embodiment. The device 20 is configured to carry out the previously described method V. Accordingly, all statements made in connection with method V also apply to the device 20.

[0068] The device 20 may comprise an electromagnetic actuator 1 containing a coil 1a for generating a magnetic field and a movable armature 1b. A measuring device 21 may be provided to measure the electrical current through the coil 1a and the voltage across the coil 1a. These measured values ​​are transmitted to a processing unit 23. Furthermore, the device 20 may comprise a storage unit 22 that can store and provide reference characteristics.

[0069] The processing unit 23 is configured to process the measured values ​​for current and voltage and to calculate the interlinked magnetic flux in the electromagnetic actuator 1, in particular in the coil 1a. Furthermore, the processing unit 23 can create an actual characteristic curve that describes the course of the interlinked magnetic flux as a function of the current. From this actual characteristic curve and the reference characteristic curve provided in the memory unit 22, the processing unit 23 can determine switching times.

[0070] If a short active phase is to be implemented, a switching duration between these two times can be calculated after determining a switch-on time and a subsequent switch-off time. For a short passive phase, the switching duration between the switch-off time and the next switch-on time can be determined. If this switching duration deviates from a specified switching duration, the processing unit 23 can adjust the actuator control accordingly for subsequent switching operations.

[0071] In summary, the present invention relates to a control device and a method for determining switching times of an electromagnetic actuator, a device for implementing the method, and a computer program. The actual characteristic curve, which describes the course of the interlinked magnetic flux as a function of the current strength, is compared with a reference characteristic curve to derive switching times. This method can be used to precisely determine switching times even for very short switching durations, even if the actuator is not yet fully deflected when switched off. The determined switching times make it possible to detect and compensate for fluctuations in the switching behavior of the actuator caused by external influences. REFERENCE SYMBOL 1 electromechanical actuator 1a coil 1b movable anchors 10 Control device 11 first process module 12 second process module 13 third process module 20 Device for carrying out the method 21 Measuring device 22 storage unit 23 Processing unit 100 Actual characteristic curve for a long switching time 101, 102, 111, 112 positions on the actual characteristic curve 200 Actual characteristic curve for a short switching time 300 Reference characteristic curve 301, 302 Reference characteristic curve sections 320 negative offset V Procedure S1-S4 process steps

Claims

[1] Control device (10) for determining switching times of an electromagnetic actuator (1), comprising: - a first process module (11) designed to determine a course of a concatenated magnetic flux as a function of a current intensity for controlling the electromagnetic actuator (1) as an actual characteristic curve (200); - a second process module (12) designed to provide at least one reference characteristic curve (300) for the magnetic flux as a function of the current intensity for controlling the electromagnetic actuator (1), wherein the reference characteristic curve (300) has a first characteristic curve section (301), wherein the first characteristic curve section (301) has a linear profile with a defined gradient and a negative offset (320), wherein the negative offset (320) is selected such that during a switching operation in which the electromagnetic actuator (1) is not moved, the first characteristic curve section (301) of the reference characteristic curve (300) is not exceeded, and wherein the slope of the first characteristic curve section (301) corresponds to a slope of the actual characteristic curve at the beginning of switching off the electromagnetic actuator (1), wherein the reference characteristic curve (300) has a second characteristic curve section (302) whose gradient corresponds to the actual characteristic curve at the beginning of switching on the electromagnetic actuator (1) and which includes a positive offset, and wherein the switching off begins with switching off the power supply of the electromagnetic actuator (1); and - a third process module (13) designed to determine a switching time of the electromagnetic actuator (1) using a comparison of values ​​of the actual characteristic curve (200) with values ​​of the at least one reference characteristic curve (300). [2] Control device (10) according to claim 1, wherein the values ​​of the actual characteristic curve (200) correspond to a predeterminable armature position of a movable armature (1b) of the electromagnetic actuator (1). [3] Control device (10) according to one of the preceding claims, wherein the interlinked magnetic flux is determined from a current and a voltage measurement in the magnetic field generating circuit during operation of the electromagnetic actuator (1). [4] Control device (10) according to one of the preceding claims, wherein the switching times comprise switching on and / or switching off the electromagnetic actuator (1). [5] Control device (10) according to one of the preceding claims, wherein a generic and / or batch-specific reference characteristic curve is provided for the electromagnetic actuator (1). [6] Control device (10) according to one of the preceding claims, wherein the reference characteristic curve (300) can be adapted and / or trained to the actual characteristic curve (200) using a machine learning model. [7] Control device (10) according to one of the preceding claims, wherein the positive offset is dimensioned such that the value of the reference characteristic curve (300) lies in a predetermined interval during a switch-off process. [8] Control device (10) according to one of the preceding claims, wherein the electromagnetic actuator (1) is a metering switching valve. [9] Method (V) for determining switching times of an electromagnetic actuator (1), comprising the following method steps: - Providing (S1) at least one reference characteristic curve (300) for a magnetic flux as a function of a current intensity for controlling the electromagnetic actuator (1), wherein the reference characteristic curve (300) has a first characteristic curve section (301), wherein the first characteristic curve section (301) has a linear profile with a defined gradient and a negative offset (320), wherein the negative offset (320) is selected such that during a switching operation in which the electromagnetic actuator (1) is not moved, the first characteristic curve section (301) of the reference characteristic curve (300) is not exceeded, and wherein the slope of the first characteristic curve section (301) corresponds to a slope of the actual characteristic curve at the beginning of switching off the electromagnetic actuator (1), wherein the reference characteristic curve (300) has a second characteristic curve section (302) whose gradient corresponds to the actual characteristic curve at the beginning of switching on the electromagnetic actuator (1) and which includes a positive offset, and wherein the switching off begins with switching off the power supply of the electromagnetic actuator (1); - switching (S2) of the electromagnetic actuator (1); - determining (S3) a profile of the linked magnetic flux as a function of a current intensity during the control of the electromagnetic actuator (1) as an actual characteristic curve (200); and - Comparing (S4) values ​​of the actual characteristic curve (200) with values ​​of the reference characteristic curve (300) and determining a switching time using the comparison of the values ​​of the actual characteristic curve (200) with the values ​​of the reference characteristic curve (300). [10] Method (V) according to claim 9, wherein determining a switching time comprises determining a switch-on time and determining a switch-off time, and wherein the process (V) comprises: - Determining a switching duration between the determined switch-on time and the determined switch-off time; - adjusting a time period between switching on the electromagnetic actuator (1) and switching off the electromagnetic actuator (1) for a subsequent switching operation using the determined switching duration between the determined switch-on time and the determined switch-off time. [11] Device (20) for carrying out a method (V) for determining switching times of an electromagnetic actuator (1) according to one of method claims 9 or 10, comprising: - an electromagnetic actuator (1) with a coil (1a) for generating a magnetic field and a movable armature (1b), - at least one measuring device (21) for measuring a current and a voltage in the magnetic field generating circuit, - at least one memory unit (22) for storing reference characteristics, and - at least one processing unit (23) by means of which values ​​of the actual characteristic curve (200) and the reference characteristic curve (300) are comparable and a switching time is determined using a comparison of the values ​​of the actual characteristic curve (200) with the values ​​of the reference characteristic curve (300). [12] Computer program, wherein the computer program is loadable into a memory unit of a control device (10) according to one of the preceding claims 1 to 8 and contains program code sections to cause the control device (10) to execute the method (V) for determining switching times of an electromagnetic actuator (1) according to one of the method claims 9 or 10 when the computer program is executed in the control device (10).

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