WO2010034334A1 - Method and microelectromechanical system for capturing a measurement variable for an electric current flowing through an electrical conductor, and an arrangement - Google Patents
Method and microelectromechanical system for capturing a measurement variable for an electric current flowing through an electrical conductor, and an arrangement Download PDFInfo
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- WO2010034334A1 WO2010034334A1 PCT/EP2008/008359 EP2008008359W WO2010034334A1 WO 2010034334 A1 WO2010034334 A1 WO 2010034334A1 EP 2008008359 W EP2008008359 W EP 2008008359W WO 2010034334 A1 WO2010034334 A1 WO 2010034334A1
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- electrical conductor
- measuring coil
- current
- microelectromechanical
- microelectromechanical system
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/146—Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/028—Electrodynamic magnetometers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/028—Electrodynamic magnetometers
- G01R33/0283—Electrodynamic magnetometers in which a current or voltage is generated due to relative movement of conductor and magnetic field
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/028—Electrodynamic magnetometers
- G01R33/0286—Electrodynamic magnetometers comprising microelectromechanical systems [MEMS]
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
- H01H47/002—Monitoring or fail-safe circuits
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R21/00—Arrangements for measuring electric power or power factor
- G01R21/06—Arrangements for measuring electric power or power factor by measuring current and voltage
Definitions
- Microelectromechanical systems often referred to as microsystems, find application in a variety of applications, such as acceleration and tilt sensors.
- the present invention relates to a method for detecting a measured variable for an electric current flowing through an electrical conductor by means of a microelectromechanical system.
- the present invention has the object y nnrun.de to provide a versatile and particularly efficient method of the aforementioned type.
- This object is achieved according to the invention by a method for detecting a measured variable for an electrical current flowing through an electrical conductor by means of a microelectromechanical system, wherein a measuring coil moves in the electric field caused by the electric current magnetic field of the electrical conductor by means of a microelectromechanical oscillator is that a cyclic change of the magnetic coil passing through the measuring coil is effected, and a voltage induced in the measuring coil due to the change of the magnetic coil passing through the magnetic flux detected voltage as a measure of the current flowing through the electrical conductor current.
- the method according to the invention thus makes use of an inductive principle in order to detect the measured variable for the electrical current flowing through the electrical conductor by means of the microelectromechanical system.
- a measuring coil is moved in the magnetic field caused by the electric current and surrounding the electrical conductor by means of a microelectromechanical or micromechanical oscillator.
- Corresponding oscillators which are also referred to as microelectromechanical or micromechanical oscillators, are also available on the market with comparatively high oscillation frequencies, i. approximately in the kHz and MHz range, comparatively inexpensive available.
- the measuring coil is now moved by the microelectromechanical oscillator in such a way that the magnetic flux, which passes through the measuring coil due to the present magnetic field, changes cyclically.
- the movement of the measuring coil has a component which is perpendicular to the longitudinal direction of the electrical conductor. Since the magnet surrounding the electrical conductor As the magnetic field decreases with increasing distance from the electrical conductor and the magnetic field is thus inhomogeneous, a corresponding movement of the measuring coil by the microelectromechanical oscillator causes a change in the magnetic flux passing through the measuring coil.
- This change in the magnetic flux passing through the measuring coil induces, in accordance with the law of induction in the measuring coil, an induction voltage that is proportional to the current flowing in the electrical conductor and thus can be detected as a measure of this current. Due to the cyclic change of the magnetic flux passing through the measuring coil caused by the electromechanical oscillator, a permanent and therefore particularly stable induced voltage is advantageously achieved in this case.
- the method according to the invention is advantageous, since it makes possible a galvanically isolated detection of a measured variable for an electrical current flowing through an electrical conductor by means of a microelectromechanical system.
- a corresponding electrical isolation usually has particular advantages in terms of safety, accuracy of measurement and the prevention of ground loops and electromagnetic interference.
- the method according to the invention has the particular advantage that the electric current to be measured or to be detected does not flow through the microelectromechanical system itself.
- the method according to the invention is furthermore distinguished, in particular, by being comparatively simple and inexpensive to implement by means of available microelectrical oscillators.
- sensing the induced voltage as a measure of the current flowing through the electrical conductor by conventional microelectromechanical vibration systems, i. Oscillators, resulting in a sufficient signal amplitude of the induced voltage.
- the amplitude of the movement of the measuring coil and its frequency is advantageously chosen as large or high.
- an increase in the area of the measuring coil and an increase in the number of turns it causes an increase in the induced voltage obtained.
- this may also be necessary for a higher isolation distance, i. for increasing the distance between the electrical conductor and the measuring coil.
- the inventive method is riprsrt pronounced that the ⁇ ess-SpuIe between a forward and a return conductor of the electrical conductor is moved.
- This offers the advantage that the signal strength of the induced voltage is further increased.
- a greater isolation distance can be selected.
- the forward and return conductors of the electrical conductor or the electrical conductor can have any shape as such in the context of the method according to the invention.
- the measuring coil is moved between a forward and a return conductor in the form of the legs of a U-shaped electrical conductor.
- U-shaped electrical conductor is a form of an electrical conductor with a forward and a return conductor that is particularly easy to implement and to operate. It should be noted at this point that the return conductor and the return conductor will usually have a comparatively small distance from each other due to the use of a microelectromechanical system for detecting the induced voltage and the associated comparatively small deflection of the measuring coil, which is usually in the micrometer - will be up to millimeter range.
- the method according to the invention is suitable based on the detected induced voltage for detecting the flow of an electric current.
- the method according to the invention is suitable based on the detected induced voltage for detecting the flow of an electric current.
- the current flowing through the electrical conductor is determined from the detected induced voltage. This offers the advantage of being a quantitative determination of the current flowing through the electrical conductor is made possible. In this case, the current can be determined either only in absolute terms or taking into account the current direction.
- the invention further relates to a microelectromechanical system for detecting a measured variable for an electric current flowing through an electrical conductor.
- the present invention has for its object to provide a microelectromechanical system for detecting a measured variable for an electric current flowing through an electrical conductor, which is versatile and particularly powerful.
- a microelectromechanical system for detecting a measured variable for an electric current flowing through an electrical conductor with a measuring coil and a microelectromechanical oscillator for moving the measuring coil such that upon movement of the measuring coil in the by the electrical current caused magnetic field of the electrical conductor a cyclic change of the measuring coil passing through the magnetic flux is caused, wherein the system for detecting a induced in the measuring coil due to the change of the magnetic coil passing through the magnetic flux induced voltage Ait> Hessgrße for the is formed by the electric conductor flowing current.
- the microelectromechanical system according to the invention is configured such that it is designed to determine the current flowing through the electrical conductor from the detected induced voltage.
- a microelectromechanical capacitive voltmeter for detecting the voltage of the electrical conductor.
- a microelectromechanical capacitive voltmeter is known, for example, from the published international application WO 2005/121819 A1.
- the additional provision of a microelectromechanical capacitive voltmeter offers the advantage that in addition to the detection of a measured variable for the current flowing through the electrical conductor or in addition to the determination of this current, a voltage measurement can continue to be carried out.
- the microelectromechanical system according to the invention is designed such that the voltmeter is mechanically coupled to the microelectromechanical oscillator.
- This offers the advantage that both the induced voltage as a measured variable for the flowing current and the voltage of the electrical conductor can be detected by means of the microelectromechanical oscillator of the microelectromechanical system.
- a particularly compact design of the microelectromechanical system is made possible;
- advantages result from this. visibly the production costs for a corresponding microelectromechanical system.
- the microelectromechanical system according to the invention is developed in such a way that an electronic circuit for determining the electrical power from the voltage induced in the measuring coil and the voltage detected by the voltmeter is provided.
- a corresponding electronic circuit can be realized for example by a microcontroller or by an ASIC (Application Specific Integrated Circuit).
- the electronic circuit is integrated directly on the chip or semiconductor component carrying the microelectromechanical oscillator.
- the electronic circuit is realized by means of a separate chip which is electrically connected to the chip carrying the microelectromechanical oscillator. In this case, the total microelectromechanical system in the form of the Wattmeter thus includes both chips.
- the invention furthermore includes an arrangement having a microelectromechanical system according to the invention or a microelectromechanical system according to one of the preferred refinements of the microelectromechanical system according to the invention and the electrical conductor through which the electrical current flows.
- the arrangement according to the invention is configured such that the electrical conductor has a forward and a return conductor and the microelectromechanical oscillator for moving the measuring coil between the outgoing and the return conductor of the electrical conductor is formed.
- FIG. 1 shows a schematic sketch to illustrate an embodiment of the method according to the invention
- Figure 2 is another schematic sketch to further
- FIG. 3 shows an exemplary embodiment of the arrangement according to the invention with an exemplary embodiment of the microelectromechanical system according to the invention.
- Figure 1 shows a schematic diagram to illustrate an embodiment of the method according to the invention. Shown is a cross section perpendicular to the direction of an electrical conductor EL, which consists of a forward and a return conductor. In the electrical conductor EL, an electric current I flows, the current direction is indicated in the usual manner. Due to the current I flowing in the electrical conductor EL, a magnetic field B is formed around the electrical conductor EL.
- a measuring coil L which has two windings in the exemplary embodiment shown and is formed in a flat shape ,
- the measuring coil L is mounted on a carrier T, which is moved by means of a micromechanical or microelectromechanical oscillator (not shown for reasons of clarity) in such a way that a cyclical change of the magnetic flux passing through the measuring coil L is effected.
- a swinging of the microelectromechanical oscillator and thus also the measuring coil L connected to the carrier T takes place in the direction of movement D indicated by the double arrow, ie perpendicular to the path of the electrical conductor EL.
- a voltage is induced in the measuring coil L which leads to the electrical current flowing through the electrical conductor EL Current T and thus represents a measured variable for this.
- the measuring coil L deviating from the representation of Figure 1, of course, in a magnetic field of a single electrical conductor, that could not be moved between a forward and a return conductor.
- the embodiment shown in FIG. 1 has the advantage that due to the fact that the measuring coil L is moved between the forward and the return conductor of the electrical conductor EL, the voltage induced in the measuring coil L has a greater magnitude Having amplitude. The reason for this is that by means of the movement of the measuring coil L between the forward and the return conductor a particularly strong change in the magnetic flux passing through the measuring coil L is effected.
- the arrangement shown in FIG. 1 could be designed, for example, such that for an electrical conductor EL with a width of 2mm, the distance between the measuring coil L and the surface of the electrical conductor EL is half a millimeter. Accordingly, the measuring coil L in the representation of FIG. 1 could have a horizontal extent of the order of magnitude of 1 mm and the amplitude of the cyclic movement effected by the microelectromechanical oscillator could be for example half a millimeter. It should, however, be emphasized that the stated values are merely examples and, depending on the respective requirements and the particular application, arrangements with possibly significantly different values are also conceivable.
- FIG. 2 shows a further schematic sketch for the rest
- Clarification of the embodiment of the method according to the invention Shown here is a perspective view of a substantially corresponding to the figure 1 arrangement, for better illustration, the carrier of the measuring coil L has been omitted. It can be seen that the measuring coil L is moved between a forward and a return conductor in the form of the legs of a U-shaped electrical conductor EL, wherein the direction of movement D is again indicated by a corresponding arrow.
- the component of the magnetic field B resulting in a current I flowing through the electrical conductor EL and the magnetic field caused by this current I in the movement direction D is sketched as Hx as a function of the position x in the direction of movement D in the graph G.
- the magnetic field Hx changes in the direction of movement D, so that a change in the magnetic flux passing through the measuring coil L occurs when the measuring coil L moves in the locking direction D.
- a Voltage induces, which is a measure of the current flowing through the electrical conductor EL current I.
- the oscillation frequency of the micro-electro-mechanical oscillator is preferably selected in the range of several kilohertz to in the megahertz range. It should be noted that the oscillation frequency of the microelectromechanical oscillator is preferably chosen such that the spectral components of the electric current I in the range of the operating frequency of the microelectromechanical oscillator can be neglected. For this purpose, bandpass filtering with a low bandwidth is advantageously provided, and the operating frequency of the microelectromechanical oscillator is significantly greater, ie, for example, a factor 10 to 100 greater than the maximum frequencies occurring in the spectrum of the electric current I having a significant amplitude.
- the operating frequency is in the range of at least 10 kHz.
- FIG. 3 shows an exemplary embodiment of the invention
- micro-electro-mechanical system MEMS which consists of an armature A, a measuring coil L, two first electrodes ETDl and a second electrode ETD2.
- armature A armature A
- measuring coil L two first electrodes
- ETDl first electrodes
- ETD2 second electrode
- U-shaped electrical conductor EL is illustrated. It should generally be pointed out at this point that the electrical conductor EL is basically also a component of the can be the actual measuring device.
- a current to be measured is thus introduced into the electrical conductor EL, which in this case will usually be arranged in the measuring device at a fixed distance from the microelectromechanical system MEMS.
- the electrical conductor EL may also be part of any other component, in which case the actual measuring device thus does not include the electrical conductor EL.
- a microelectromechanical oscillator is formed by the armature A as well as the first electrodes ETD1 and the second electrode ETD2.
- the oscillatable part of the oscillator which is given by the second electrode ETD2, suspended from the armature A.
- an air gap SP whose width will usually be in the micrometer range.
- a measuring coil L which again has two turns in the illustrated example, is mounted on the second electrode ETD2, so that the measuring coil L is moved in such a way by means of the microelectromechanical oscillator that due to the movement of the Measuring coil L in which caused by the electric current I magnetic field of the electrical conductor EL a cyclic change of the measuring coil L passing through rr. ⁇ gneti- rule flow is effected.
- a voltage is induced in the measuring coil L, which voltage is detected by corresponding means and from which the voltage in the electric conductor EL flowing current I can be determined.
- microelectromechanical oscillators which operate on a principle other than an electrostatic principle.
- a measuring coil with only one or even more than two turns can be used.
- the microelectromechanical system shown in FIG. 3 may additionally have a capacitive voltmeter for detecting the voltage of the electrical conductor EL.
- a corresponding microelectromechanical system for capacitive voltage measurement is known, for example, from the previously mentioned WO 2005/121819 A1.
- the voltage meter is preferably coupled to the microelectromechanical oscillator, so that the movement effected by the oscillator not only causes the change of the magnetic flux passing through the measuring coil, but also causes a change in capacitance required in the context of the voltage measurement.
- microelectromechanical system according to the invention and the method according to the invention have in particular the
- the microelectromechanical system and the method are furthermore particularly advantageous, in particular also with regard to their applicability at comparatively high current intensities powerful.
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Abstract
Description
Beschreibung description
Verfahren und mikroelektromechanisches System zum Erfassen einer Messgröße für einen durch einen elektrischen Leiter fließenden elektrischen Strom sowie AnordnungMethod and microelectromechanical system for detecting a measured variable for an electric current flowing through an electrical conductor and arrangement
Mikroelektromechanische Systeme (Micro-Electro-Mechanical- Systems, MEMS) , die häufig auch als Mikrosysteme bezeichnet werden, finden in unterschiedlichen Anwendungsbereichen, wie beispielsweise als Beschleunigungs- und Neigungssensoren,Microelectromechanical systems (MEMS), often referred to as microsystems, find application in a variety of applications, such as acceleration and tilt sensors.
Drehratesensoren oder Drucksensoren, zunehmende Verbreitung. Die Vorteile mikroelektromechanischer Systeme liegen dabei insbesondere in ihrer geringen Größe, ihrem vergleichsweise geringen Preis sowie ihrer hohen Zuverlässigkeit.Yaw rate sensors or pressure sensors, increasing prevalence. The advantages of microelectromechanical systems are in particular their small size, their relatively low price and their high reliability.
Die vorliegende Erfindung betrifft ein Verfahren zum Erfassen einer Messgröße für einen durch einen elektrischen Leiter fließenden elektrischen Strom mittels eines mikroelektrome- chanischen Systems.The present invention relates to a method for detecting a measured variable for an electric current flowing through an electrical conductor by means of a microelectromechanical system.
Ein solches Verfahren ist aus der Patentschrift US 6,188,322 Bl bekannt. Diese beschreibt ein Verfahren zur Strommessung mittels eines mikroelektromechanischen Systems, wobei ein elektrischer Strom dadurch gemessen wird, dass er in einen elektrischen Leiter in Form eines auslenkbaren mikroelektromechanischen Sensorelementes eingespeist wird. Aufgrund dessen, dass das Sensorelement in einem Magnetfeld angeordnet ist, ergibt sich eine Auslenkung des Sensorelementes, die als Messgröße für den fließenden elektrischen Strom erfasst wird.Such a method is known from the patent US 6,188,322 Bl. This describes a method for measuring current by means of a microelectromechanical system, wherein an electric current is measured by being fed into an electrical conductor in the form of a deflectable microelectromechanical sensor element. Due to the fact that the sensor element is arranged in a magnetic field, there is a deflection of the sensor element, which is detected as a measured variable for the flowing electric current.
Der vorliegenden Erfindung liegt die Aufgabe ynnrun.de, ein vielseitig einsetzbares und besonders leistungsfähiges Verfahren der zuvor genannten Art anzugeben. Diese Aufgabe wird erfindungsgemäß gelöst durch ein Verfahren zum Erfassen einer Messgröße für einen durch einen elektrischen Leiter fließenden elektrischen Strom mittels eines mik- roelektromechanischen Systems, wobei eine Mess-Spule in dem durch den elektrischen Strom bewirkten Magnetfeld des elektrischen Leiters mittels eines mikroelektromechanischen Oszillators derart bewegt wird, dass eine zyklische Änderung des die Mess-Spule durchsetzenden magnetischen Flusses bewirkt wird, und eine in der Mess-Spule aufgrund der Änderung des die Mess-Spule durchsetzenden magnetischen Flusses induzierte Spannung als Messgröße für den durch den elektrischen Leiter fließenden Strom erfasst wird.The present invention has the object y nnrun.de to provide a versatile and particularly efficient method of the aforementioned type. This object is achieved according to the invention by a method for detecting a measured variable for an electrical current flowing through an electrical conductor by means of a microelectromechanical system, wherein a measuring coil moves in the electric field caused by the electric current magnetic field of the electrical conductor by means of a microelectromechanical oscillator is that a cyclic change of the magnetic coil passing through the measuring coil is effected, and a voltage induced in the measuring coil due to the change of the magnetic coil passing through the magnetic flux detected voltage as a measure of the current flowing through the electrical conductor current.
Vorteilhafterweise macht sich das erfindungsgemäße Verfahren somit ein induktives Prinzip zu Nutze, um die Messgröße für den durch den elektrischen Leiter fließenden elektrischen Strom mittels des mikroelektromechanischen Systems zu erfassen. Hierzu wird eine Mess-Spule in dem durch den elektrischen Strom bewirkten, den elektrischen Leiter umgebenden Magnetfeld mittels eines mikroelektromechanischen beziehungsweise mikromechanischen Oszillators bewegt. Entsprechende Oszillatoren, die auch als mikroelektromechanische beziehungsweise mikromechanische Schwinger bezeichnet werden, sind auf dem Markt auch mit vergleichsweise hohen Schwingungsfrequen- zen, d.h. etwa im kHz- und MHz-Bereich, vergleichsweise kostengünstig verfügbar.Advantageously, the method according to the invention thus makes use of an inductive principle in order to detect the measured variable for the electrical current flowing through the electrical conductor by means of the microelectromechanical system. For this purpose, a measuring coil is moved in the magnetic field caused by the electric current and surrounding the electrical conductor by means of a microelectromechanical or micromechanical oscillator. Corresponding oscillators, which are also referred to as microelectromechanical or micromechanical oscillators, are also available on the market with comparatively high oscillation frequencies, i. approximately in the kHz and MHz range, comparatively inexpensive available.
Durch den mikroelektromechanischen Oszillator wird die Mess- Spule erfindungsgemäß nun derart bewegt, dass sich der magne- tische Fluss, der aufgrund des vorliegenden Magnetfelds die Mess-Spule durchsetzt, zyklisch ändert. Hierzu ist cc erforderlich, dass die Bewegung der Mess-Spule eine Komponente aufweist, die senkrecht zur Längsrichtung des elektrischen Leiters steht. Da das den elektrischen Leiter umgebende Mag- netfeld mit zunehmender Entfernung von dem elektrischen Leiter abnimmt und das Magnetfeld somit dahingehend inhomogen ist, bewirkt eine entsprechende Bewegung der Mess-Spule durch den mikroelektromechanischen Oszillator eine Änderung des die Mess-Spule durchsetzenden magnetischen Flusses. Diese Änderung des die Mess-Spule durchsetzenden magnetischen Flusses induziert gemäß dem Induktionsgesetz in der Mess-Spule eine Induktionsspannung, die zu dem in dem elektrischen Leiter fließenden Strom proportional ist und somit als Messgröße für diesen Strom erfasst werden kann. Aufgrund der durch den elektromechanischen Oszillator bewirkten zyklischen Änderung des die Mess-Spule durchsetzenden magnetischen Flusses wird hierbei vorteilhafterweise eine dauerhafte und damit besonders stabile induzierte Spannung erreicht.According to the invention, the measuring coil is now moved by the microelectromechanical oscillator in such a way that the magnetic flux, which passes through the measuring coil due to the present magnetic field, changes cyclically. For this cc is required that the movement of the measuring coil has a component which is perpendicular to the longitudinal direction of the electrical conductor. Since the magnet surrounding the electrical conductor As the magnetic field decreases with increasing distance from the electrical conductor and the magnetic field is thus inhomogeneous, a corresponding movement of the measuring coil by the microelectromechanical oscillator causes a change in the magnetic flux passing through the measuring coil. This change in the magnetic flux passing through the measuring coil induces, in accordance with the law of induction in the measuring coil, an induction voltage that is proportional to the current flowing in the electrical conductor and thus can be detected as a measure of this current. Due to the cyclic change of the magnetic flux passing through the measuring coil caused by the electromechanical oscillator, a permanent and therefore particularly stable induced voltage is advantageously achieved in this case.
Das erfindungsgemäße Verfahren ist vorteilhaft, da es eine galvanisch getrennte Erfassung einer Messgröße für einen durch einen elektrischen Leiter fließenden elektrischen Strom mittels eines mikroelektromechanischen Systems ermöglicht. Eine entsprechende galvanische Trennung weist in Abhängigkeit von dem jeweiligen Anwendungsfall üblicherweise insbesondere Vorteile hinsichtlich der Sicherheit, der Messgenauigkeit sowie der Verhinderung von Brummschleifen und elektromagnetischen Störungen auf. Darüber hinaus weist das erfindungsgemä- ße Verfahren insbesondere den Vorteil auf, dass der zu messende beziehungsweise zu erfassende elektrische Strom nicht durch das mikroelektromechanische System selbst fließt. Dadurch, dass aus der induktiv erfassten Messgröße in Form der induzierten Spannung eine Bestimmung des in dem elektrischen Leiter fließenden elektrischen Stromes unter Einhaltung eines Isolationsabstandes zu dem elektr.i sr.hpη Leiter möglich ist, wird eine Beeinträchtigung des mikroelektromechanischen Systems durch den in dem elektrischen Leiter fließenden elektrischen Strom zuverlässig vermieden. Dies gilt insbesondere auch im Hinblick auf hohe Stromstärken, die etwa im Falle des aus der US 6,188,322 Bl bekannten Verfahrens aufgrund des Fließens des zu messenden Stroms durch das mikroelektromecha- nische Sensorelement zu einer Beschädigung beziehungsweise Zerstörung des mikroelektromechanischen Systems führen könnten.The method according to the invention is advantageous, since it makes possible a galvanically isolated detection of a measured variable for an electrical current flowing through an electrical conductor by means of a microelectromechanical system. Depending on the particular application, a corresponding electrical isolation usually has particular advantages in terms of safety, accuracy of measurement and the prevention of ground loops and electromagnetic interference. In addition, the method according to the invention has the particular advantage that the electric current to be measured or to be detected does not flow through the microelectromechanical system itself. In that from the inductively detected measured quantity in the form of the induced voltage, a determination of the current flowing in the electrical conductor electrical current while maintaining an insulating spacing is possible to elektr.i sr.h p η conductor, a deterioration of the micro-electro-mechanical system by the in the electrical conductor flowing electrical current reliably avoided. This is especially true also with regard to high currents, which, for example in the case of the method known from US Pat. No. 6,188,322 B1, could lead to damage or destruction of the microelectromechanical system due to the flow of the current to be measured through the microelectromechanical sensor element.
Das erfindungsgemäße Verfahren zeichnet sich weiterhin insbesondere dadurch aus, dass es mittels verfügbarer mikroelekt- romechanischer Oszillatoren vergleichsweise einfach und kostengünstig realisierbar ist. So haben entsprechende Untersuchungen gezeigt, dass ein Erfassen der induzierten Spannung als Messgröße für den durch den elektrischen Leiter fließenden Strom mittels herkömmlicher mikroelektromechanischer Schwingungssysteme, d.h. Oszillatoren, zu einer ausreichenden Signalamplitude der induzierten Spannung führt. Um ein möglichst hohes Signal zu erzielen, d.h. eine möglichst große in der Mess-Spule induzierte Spannung zu erfassen, wird dabei die Amplitude der Bewegung der Mess-Spule sowie ihre Frequenz vorteilhafterweise möglichst groß beziehungsweise hoch gewählt. Darüber hinaus bewirkt auch eine Vergrößerung der Fläche der Mess-Spule sowie eine Erhöhung der Anzahl ihrer Windungen eine Erhöhung der erzielten induzierten Spannung. Neben einer Verbesserung der Signalstärke kann dies vorteil- hafterweise erforderlichenfalls auch für einen höheren Isolationsabstand, d.h. für eine Vergrößerung des Abstands zwischen dem elektrischen Leiter und der Mess-Spule, genutzt werden.The method according to the invention is furthermore distinguished, in particular, by being comparatively simple and inexpensive to implement by means of available microelectrical oscillators. Thus, studies have shown that sensing the induced voltage as a measure of the current flowing through the electrical conductor by conventional microelectromechanical vibration systems, i. Oscillators, resulting in a sufficient signal amplitude of the induced voltage. In order to achieve the highest possible signal, i. To detect the greatest possible induced in the measuring coil voltage, the amplitude of the movement of the measuring coil and its frequency is advantageously chosen as large or high. In addition, an increase in the area of the measuring coil and an increase in the number of turns it causes an increase in the induced voltage obtained. In addition to an improvement in the signal strength, this may also be necessary for a higher isolation distance, i. for increasing the distance between the electrical conductor and the measuring coil.
In einer besonders bevorzugten Ausführungsform ist das erfindungsgemäße Verfahren riprsrt ausgeprägt, dass die πess-SpuIe zwischen einem Hin- und einem Rückleiter des elektrischen Leiters bewegt wird. Dies bietet den Vorteil, dass die Signalstärke der induzierten Spannung weiter erhöht wird bezie- hungsweise alternativ, sofern erforderlich, ein größerer Isolationsabstand gewählt werden kann. Darüber hinaus werden durch die Bewegung der Mess-Spule zwischen dem Hin- und dem Rückleiter des elektrischen Leiters externe Störfelder, wie sie in der Praxis etwa beim Einsatz in industrietechnischen Anlagen häufig auftreten, vorteilhafterweise zumindest weitgehend in ihrer Auswirkung auf das Messergebnis unterdrückt.In a particularly preferred embodiment, the inventive method is riprsrt pronounced that the πess-SpuIe between a forward and a return conductor of the electrical conductor is moved. This offers the advantage that the signal strength of the induced voltage is further increased. Alternatively, if necessary, a greater isolation distance can be selected. In addition, by the movement of the measuring coil between the forward and the return conductor of the electrical conductor external interference fields, as they often occur in practice when used in industrial equipment, advantageously at least largely suppressed their effect on the measurement result.
Grundsätzlich können der Hin- und der Rückleiter des elektri- sehen Leiters beziehungsweise der elektrische Leiter als solcher im Rahmen des erfindungsgemäßen Verfahrens eine beliebige Form aufweisen. In einer besonders bevorzugten Weiterbildung des erfindungsgemäßen Verfahrens wird die Mess-Spule zwischen einem Hin- und einem Rückleiter in Form der Schenkel eines U-förmig ausgebildeten elektrischen Leiters bewegt.In principle, the forward and return conductors of the electrical conductor or the electrical conductor can have any shape as such in the context of the method according to the invention. In a particularly preferred embodiment of the method according to the invention, the measuring coil is moved between a forward and a return conductor in the form of the legs of a U-shaped electrical conductor.
Dies bietet den Vorteil, dass es sich bei einem U-förmig ausgebildeten elektrischen Leiter um eine besonders einfach zu realisierende und zu betreibende Form eines elektrischen Leiters mit einem Hin- und einem Rückleiter handelt. Es sei an dieser Stelle darauf hingewiesen, dass der Hin- und der Rückleiter aufgrund der Verwendung eines mikroelektromechanischen Systems zum Erfassen der induzierten Spannung und der damit verbundenen vergleichsweise geringen Auslenkung der Mess- Spule üblicherweise einen vergleichsweise geringen Abstand zueinander aufweisen werden, der üblicherweise im Mikrometer- bis Millimeterbereich liegen wird.This offers the advantage that a U-shaped electrical conductor is a form of an electrical conductor with a forward and a return conductor that is particularly easy to implement and to operate. It should be noted at this point that the return conductor and the return conductor will usually have a comparatively small distance from each other due to the use of a microelectromechanical system for detecting the induced voltage and the associated comparatively small deflection of the measuring coil, which is usually in the micrometer - will be up to millimeter range.
Grundsätzlich ist das erfindungsgemäße Verfahren basierend auf der erfassten induzierten Spannung zum Nachweis des Flie- ßens eines elektrischen Stromes geeignet. Darüber hinaus kannIn principle, the method according to the invention is suitable based on the detected induced voltage for detecting the flow of an electric current. In addition, can
geprägt sein, dass aus der erfassten induzierten Spannung der durch den elektrischen Leiter fließende Strom bestimmt wird. Dies bietet den Vorteil, dass eine quantitative Bestimmung des durch den elektrischen Leiter fließenden Stromes ermöglicht wird. Dabei kann der Strom entweder lediglich betrags- maßig oder auch unter Berücksichtigung der Stromrichtung bestimmt werden.be characterized in that the current flowing through the electrical conductor is determined from the detected induced voltage. This offers the advantage of being a quantitative determination of the current flowing through the electrical conductor is made possible. In this case, the current can be determined either only in absolute terms or taking into account the current direction.
Die Erfindung betrifft des Weiteren ein mikroelektromechani- sches System zum Erfassen einer Messgroße für einen durch einen elektrischen Leiter fließenden elektrischen Strom.The invention further relates to a microelectromechanical system for detecting a measured variable for an electric current flowing through an electrical conductor.
Ein solches mikroelektromechanisches System ist ebenfalls aus der bereits angeführten Patentschrift US 6,188,322 Bl bekannt.Such a microelectromechanical system is also known from the already mentioned patent US 6,188,322 Bl.
Hinsichtlich des mikroelektromechanischen Systems liegt der vorliegenden Erfindung die Aufgabe zugrunde, ein mikroelektromechanisches System zum Erfassen einer Messgroße für einen durch einen elektrischen Leiter fließenden elektrischen Strom anzugeben, das vielseitig einsetzbar und besonders leistungsfähig ist.With regard to the microelectromechanical system, the present invention has for its object to provide a microelectromechanical system for detecting a measured variable for an electric current flowing through an electrical conductor, which is versatile and particularly powerful.
Diese Aufgabe wird erfindungsgemaß gelost durch ein mikroelektromechanisches System zum Erfassen einer Messgroße für einen durch einen elektrischen Leiter fließenden elektrischen Strom mit einer Mess-Spule und einem mikroelektromechanischen Oszillator zum Bewegen der Mess-Spule derart, dass bei Bewegung der Mess-Spule in dem durch den elektrischen Strom bewirkten Magnetfeld des elektrischen Leiters eine zyklische Änderung des die Mess-Spule durchsetzenden magnetischen Flusses bewirkt wird, wobei das System zum Erfassen einer in der Mess-Spule aufgrund der Änderung des die Mess-Spule durchsetzenden magnetischen Flusses induzierten Spannung ait> hessgroße für den durch den elektrischen Leiter fließenden Strom ausgebildet ist. Die Vorteile des erfindungsgemäßen mikroelektromechanischen Systems entsprechen im Wesentlichen denjenigen des erfindungsgemäßen Verfahrens, so dass diesbezüglich auf die entsprechenden vorstehenden Ausführungen verwiesen wird.This object is achieved according to the invention by a microelectromechanical system for detecting a measured variable for an electric current flowing through an electrical conductor with a measuring coil and a microelectromechanical oscillator for moving the measuring coil such that upon movement of the measuring coil in the by the electrical current caused magnetic field of the electrical conductor a cyclic change of the measuring coil passing through the magnetic flux is caused, wherein the system for detecting a induced in the measuring coil due to the change of the magnetic coil passing through the magnetic flux induced voltage Ait> Hessgrße for the is formed by the electric conductor flowing current. The advantages of the microelectromechanical system according to the invention essentially correspond to those of the method according to the invention, so that in this regard reference is made to the corresponding explanations above.
In einer besonders bevorzugten Weiterbildung ist das erfindungsgemäße mikroelektromechanische System derart ausgestaltet, dass es zum Bestimmen des durch den elektrischen Leiter fließenden Stroms aus der erfassten induzierten Spannung aus- gebildet ist.In a particularly preferred development, the microelectromechanical system according to the invention is configured such that it is designed to determine the current flowing through the electrical conductor from the detected induced voltage.
In einer weiteren besonders bevorzugten Weiterbildung des erfindungsgemäßen mikroelektromechanischen Systems ist ein mik- roelektromechanischer kapazitiver Spannungsmesser zum Erfas- sen der Spannung des elektrischen Leiters vorgesehen. Ein solcher mikroelektromechanischer kapazitiver Spannungsmesser ist beispielsweise aus der veröffentlichten internationalen Anmeldung WO 2005/121819 Al bekannt. Das zusätzliche Vorsehen eines mikroelektromechanischen kapazitiven Spannungsmessers bietet den Vorteil, dass neben dem Erfassen einer Messgröße für den durch den elektrischen Leiter fließenden Strom beziehungsweise neben der Bestimmung dieses Stromes weiterhin auch eine Spannungsmessung erfolgen kann.In a further particularly preferred embodiment of the microelectromechanical system according to the invention, a microelectromechanical capacitive voltmeter is provided for detecting the voltage of the electrical conductor. Such a microelectromechanical capacitive voltmeter is known, for example, from the published international application WO 2005/121819 A1. The additional provision of a microelectromechanical capacitive voltmeter offers the advantage that in addition to the detection of a measured variable for the current flowing through the electrical conductor or in addition to the determination of this current, a voltage measurement can continue to be carried out.
Vorzugsweise ist das erfindungsgemäße mikroelektromechanische System dabei derart ausgeführt, dass der Spannungsmesser mechanisch an den mikroelektromechanischen Oszillator angekoppelt ist. Dies bietet den Vorteil, dass mittels des mikroelektromechanischen Oszillators des mikroelektromechanischen Systems sowohl die induzierte Spannung als Messgröße für den fließenden Strom als auch die Spannung deε elektrischen Leiters erfasst werden kann. Hierdurch wird eine besonders kompakte Ausführung des mikroelektromechanischen Systems ermöglicht; darüber hinaus ergeben sich hierdurch Vorteile hin- sichtlich der Herstellungskosten für ein entsprechendes mik- roelektromechanisches System.Preferably, the microelectromechanical system according to the invention is designed such that the voltmeter is mechanically coupled to the microelectromechanical oscillator. This offers the advantage that both the induced voltage as a measured variable for the flowing current and the voltage of the electrical conductor can be detected by means of the microelectromechanical oscillator of the microelectromechanical system. As a result, a particularly compact design of the microelectromechanical system is made possible; In addition, advantages result from this. visibly the production costs for a corresponding microelectromechanical system.
In einer weiteren besonders bevorzugten Ausführungsform ist das erfindungsgemäße mikroelekttomechanische System derart weitergebildet, dass eine elektronische Schaltung zur Bestimmung der elektrischen Leistung aus der in der Mess-Spule induzierten Spannung und der durch den Spannungsmesser erfass- ten Spannung vorgesehen ist. Dies ist vorteilhaft, da das mikroelektromechanische System hierdurch zu einem Wattmeter erweitert wird. Eine entsprechende elektronische Schaltung kann beispielsweise durch einen MikroController oder durch einen ASIC (Application Specific Integrated Circuit) realisiert werden. Hierbei besteht einerseits die Möglichkeit, dass die elektronische Schaltung unmittelbar auf dem den mik- roelektromechanischen Oszillator tragenden Chip beziehungsweise Halbleiterbauelement integriert ist. Andererseits ist es jedoch auch denkbar, dass die elektronische Schaltung mittels eines separaten Chips realisiert wird, der an den den mikroelektromechanischen Oszillator tragenden Chip elektrisch angebunden wird. In diesem Fall schließt das mikroelektromechanische Gesamtsystem in Form des Wattmeters somit beide Chips ein.In a further particularly preferred embodiment, the microelectromechanical system according to the invention is developed in such a way that an electronic circuit for determining the electrical power from the voltage induced in the measuring coil and the voltage detected by the voltmeter is provided. This is advantageous because the microelectromechanical system is thereby expanded to a wattmeter. A corresponding electronic circuit can be realized for example by a microcontroller or by an ASIC (Application Specific Integrated Circuit). On the one hand, there is the possibility that the electronic circuit is integrated directly on the chip or semiconductor component carrying the microelectromechanical oscillator. On the other hand, however, it is also conceivable that the electronic circuit is realized by means of a separate chip which is electrically connected to the chip carrying the microelectromechanical oscillator. In this case, the total microelectromechanical system in the form of the Wattmeter thus includes both chips.
Die Erfindung umfasst darüber hinaus eine Anordnung mit einem erfindungsgemäßen mikroelektromechanischen System beziehungsweise einem mikroelektromechanischen System gemäß einer der zuvor aufgeführten bevorzugten Weiterbildungen des erfindungsgemäßen mikroelektromechanischen Systems und mit dem von dem elektrischen Strom durchflossenen elektrischen Leiter.The invention furthermore includes an arrangement having a microelectromechanical system according to the invention or a microelectromechanical system according to one of the preferred refinements of the microelectromechanical system according to the invention and the electrical conductor through which the electrical current flows.
In einer besonders bevorzugten Weiterbildung ist die erfindungsgemäße Anordnung derart ausgestaltet, dass der elektrische Leiter einen Hin- und einen Rückleiter aufweist und der mikroelektromechanische Oszillator zum Bewegen der Mess-Spule zwischen dem Hin- und dem Rückleiter des elektrischen Leiters ausgebildet ist. Hinsichtlich der Vorteile dieser Weiterbildung der erfindungsgemäßen Anordnung sei auf die vorstehenden Ausführungen im Zusammenhang mit der entsprechenden bevorzugten Weiterbildung des erfindungsgemäßen Verfahrens verwiesen.In a particularly preferred embodiment, the arrangement according to the invention is configured such that the electrical conductor has a forward and a return conductor and the microelectromechanical oscillator for moving the measuring coil between the outgoing and the return conductor of the electrical conductor is formed. With regard to the advantages of this development of the arrangement according to the invention, reference is made to the above statements in connection with the corresponding preferred development of the method according to the invention.
In einer weiteren besonders bevorzugten Weiterbildung der erfindungsgemäßen Anordnung sind der Hin- und der Rückleiter in Form der Schenkel eines U-förmig ausgebildeten elektrischenIn a further particularly preferred embodiment of the arrangement according to the invention, the forward and return conductors in the form of the legs of a U-shaped electrical
Leiters ausgeführt. Auch hinsichtlich der Vorteile dieser bevorzugten Weiterbildung sei wiederum auf die im Zusammenhang mit der entsprechenden bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens genannten Vorteile verwiesen.Ladder executed. With regard to the advantages of this preferred development, reference is again made to the advantages mentioned in connection with the corresponding preferred embodiment of the method according to the invention.
Im Folgenden wird die Erfindung anhand von Ausführungsbeispielen näher erläutert. Hierzu zeigtIn the following the invention will be explained in more detail by means of exemplary embodiments. This shows
Figur 1 eine schematische Skizze zur Verdeutlichung eines Ausführungsbeispiels des erfindungsgemäßen Verfahrens,FIG. 1 shows a schematic sketch to illustrate an embodiment of the method according to the invention,
Figur 2 eine weitere schematische Skizze zur weiterenFigure 2 is another schematic sketch to further
Verdeutlichung des Ausführungsbeispiels des erfindungsgemäßen Verfahrens undClarification of the embodiment of the method and
Figur 3 ein Ausführungsbeispiel der erfindungsgemäßen Anordnung mit einem Ausführungsbeispiel des erfindungsgemäßen mikroelektromechanischen Systems.FIG. 3 shows an exemplary embodiment of the arrangement according to the invention with an exemplary embodiment of the microelectromechanical system according to the invention.
In den Figuren werden für gleiche beziehungsweise gleich wirkende Komponenten aus Gründen der Übersichtlichkeit jeweils dieselben Bezugszeichen verwendet. Figur 1 zeigt eine schematische Skizze zur Verdeutlichung eines Ausführungsbeispiels des erfindungsgemäßen Verfahrens. Dargestellt ist ein Querschnitt senkrecht zur Verlaufsrichtung eines elektrischen Leiters EL, der aus einem Hin- und einem Rückleiter besteht. In dem elektrischen Leiter EL fließt ein elektrischer Strom I, dessen Stromrichtung in üblicher Art und Weise angedeutet ist. Aufgrund des in dem elektrischen Leiter EL fließenden Stromes I bildet sich um den elektrischen Leiter EL ein Magnetfeld B aus.In the figures, the same reference numerals are used for the same or equivalent components for reasons of clarity. Figure 1 shows a schematic diagram to illustrate an embodiment of the method according to the invention. Shown is a cross section perpendicular to the direction of an electrical conductor EL, which consists of a forward and a return conductor. In the electrical conductor EL, an electric current I flows, the current direction is indicated in the usual manner. Due to the current I flowing in the electrical conductor EL, a magnetic field B is formed around the electrical conductor EL.
Um nun mittels eines mikroelektromechanischen Systems eine Messgröße für den durch den elektrischen Leiter EL fließenden Strom I erfassen beziehungsweise diesen Strom I quantitativ messen zu können, ist eine Mess-Spule L vorgesehen, die in dem dargestellten Ausführungsbeispiel zwei Windungen aufweist und in flacher Form ausgebildet ist. Die Mess-Spule L ist auf einem Träger T angebracht, der mittels eines aus Gründen der Übersichtlichkeit nicht dargestellten mikromechanischen beziehungsweise mikroelektromechanischen Oszillators derart be- wegt wird, dass eine zyklische Änderung des die Mess-Spule L durchsetzenden magnetischen Flusses bewirkt wird. In dem beschriebenen Ausführungsbeispiel erfolgt hierbei ein Schwingen des mikroelektromechanischen Oszillators und damit auch der mit dem Träger T verbundenen Mess-Spule L in der durch den Doppelpfeil angedeuteten Bewegungsrichtung D, d.h. senkrecht zum Verlauf des elektrischen Leiters EL. Aufgrund der durch die Bewegung der Mess-Spule L in dem Magnetfeld B des elektrischen Leiters EL bewirkten Änderung des die Mess-Spule L durchsetzenden magnetischen Flusses wird in der Mess-Spule L eine Spannung induziert, die zu dem durch den elektrischen Leiter EL fließenden elektrischen Strom T und damit eine Messgröße für diesen darstellt. Es sei darauf hingewiesen, dass die Mess-Spule L abweichend von der Darstellung der Figur 1 selbstverständlich auch in einem Magnetfeld eines einzelnen elektrischen Leiters, d.h. nicht zwischen einem Hin- und einem Rückleiter, bewegt werden könnte. Ausgehend von der Darstellung der Figur 1 könnte dies beispielsweise so aussehen, dass der linke Teil des elektrischen Leiters EL in der Darstellung entfällt und der Träger T mit der Mess-Spule L nach rechts verschoben wird, so dass die Mess-Spule L um die Mitte des dann nur einen Leiter aufwei- senden elektrischen Leiters EL schwingt. Auch in diesem Fall ergibt sich eine Änderung des die Mess-Spule L durchsetzenden magnetischen Flusses, so dass auch mittels einer solchen Anordnung eine Messgröße für den durch den elektrischen Leiter EL fließenden Strom I erfassbar ist. Die in der Figur 1 dar- gestellte Ausführungsform weist jedoch den Vorteil auf, dass aufgrund dessen, dass die Mess-Spule L zwischen dem Hin- und dem Rückleiter des elektrischen Leiters EL bewegt wird, die in der Mess-Spule L induzierte Spannung eine größere Amplitude aufweist. Ursache hierfür ist, dass mittels der Bewegung der Mess-Spule L zwischen dem Hin- und dem Rückleiter eine besonders starke Änderung des die Mess-Spule L durchsetzenden magnetischen Flusses bewirkt wird.In order to be able to detect a measured variable for the current I flowing through the electrical conductor EL by means of a microelectromechanical system or to be able to measure this current I quantitatively, a measuring coil L is provided which has two windings in the exemplary embodiment shown and is formed in a flat shape , The measuring coil L is mounted on a carrier T, which is moved by means of a micromechanical or microelectromechanical oscillator (not shown for reasons of clarity) in such a way that a cyclical change of the magnetic flux passing through the measuring coil L is effected. In the described embodiment, a swinging of the microelectromechanical oscillator and thus also the measuring coil L connected to the carrier T takes place in the direction of movement D indicated by the double arrow, ie perpendicular to the path of the electrical conductor EL. Owing to the change in the magnetic flux passing through the measuring coil L caused by the movement of the measuring coil L in the magnetic field B of the electrical conductor EL, a voltage is induced in the measuring coil L which leads to the electrical current flowing through the electrical conductor EL Current T and thus represents a measured variable for this. It should be noted that the measuring coil L deviating from the representation of Figure 1, of course, in a magnetic field of a single electrical conductor, that could not be moved between a forward and a return conductor. Starting from the illustration of FIG. 1, this could, for example, be such that the left-hand part of the electrical conductor EL in the illustration is omitted and the carrier T is displaced to the right with the measuring coil L, so that the measuring coil L is moved around the middle then only a conductor aufwei- send electrical conductor EL oscillates. Also in this case results in a change of the measuring coil L passing through magnetic flux, so that by means of such an arrangement, a measured variable for the current flowing through the electrical conductor EL current I is detected. However, the embodiment shown in FIG. 1 has the advantage that due to the fact that the measuring coil L is moved between the forward and the return conductor of the electrical conductor EL, the voltage induced in the measuring coil L has a greater magnitude Having amplitude. The reason for this is that by means of the movement of the measuring coil L between the forward and the return conductor a particularly strong change in the magnetic flux passing through the measuring coil L is effected.
Um eine möglichst große induzierte Spannung zu erzielen be- ziehungsweise den Isolationsabstand zwischen der Mess-Spule L und dem elektrischen Leiter EL erforderlichenfalls vergrößern zu können, ist es weiterhin möglich, die Anzahl der Windungen beziehungsweise die Fläche der Mess-Spule L zu erhöhen beziehungsweise zu vergrößern und/oder die Amplitude der durch den mikroelektromechanischen Oszillator bewirkten Bewegung möglichst groß zu wählen.In order to achieve the greatest possible induced voltage or to be able to increase the insulation distance between the measuring coil L and the electrical conductor EL if necessary, it is furthermore possible to increase or increase the number of turns or the surface of the measuring coil L. increase and / or to select the amplitude of the movement caused by the microelectromechanical oscillator as large as possible.
Hinsichtlich ihrer Dimensionierung könnte die in Figur 1 dargestellte Anordnung beispielsweise so ausgelegt werden, dass bei einem elektrischen Leiter EL mit einer Breite von 2mm der Abstand zwischen der Mess-Spule L und der Oberfläche des elektrischen Leiters EL einen halben Millimeter beträgt. Dem entsprechend könnte die Mess-Spule L in der Darstellung der Figur 1 eine horizontale Ausdehnung in der Größenordnung von lmm aufweisen und die Amplitude der durch den mikroelektrome- chanischen Oszillator bewirkten zyklischen Bewegung beispielsweise einen halben Millimeter betragen. Es sei jedoch nachdrücklich darauf hingewiesen, dass es sich bei den ge- nannten Werten lediglich um Beispiele handelt und in Abhängigkeit von den jeweiligen Anforderungen sowie dem jeweiligen Anwendungszweck auch Anordnungen mit hiervon gegebenenfalls deutlich abweichenden Werten denkbar sind.With regard to their dimensioning, the arrangement shown in FIG. 1 could be designed, for example, such that for an electrical conductor EL with a width of 2mm, the distance between the measuring coil L and the surface of the electrical conductor EL is half a millimeter. Accordingly, the measuring coil L in the representation of FIG. 1 could have a horizontal extent of the order of magnitude of 1 mm and the amplitude of the cyclic movement effected by the microelectromechanical oscillator could be for example half a millimeter. It should, however, be emphasized that the stated values are merely examples and, depending on the respective requirements and the particular application, arrangements with possibly significantly different values are also conceivable.
Figur 2 zeigt eine weitere schematische Skizze zur weiterenFIG. 2 shows a further schematic sketch for the rest
Verdeutlichung des Ausführungsbeispiels des erfindungsgemäßen Verfahrens. Gezeigt ist hierbei eine perspektivische Darstellung einer im Wesentlichen der Figur 1 entsprechenden Anordnung, wobei zur besseren Veranschaulichung der Träger der Mess-Spule L weggelassen wurde. Erkennbar ist, dass die Mess- Spule L zwischen einem Hin- und einem Rückleiter in Form der Schenkel eines U-förmig ausgebildeten elektrischen Leiters EL bewegt wird, wobei die Bewegungsrichtung D wiederum durch einen entsprechenden Pfeil angedeutet ist. Die sich bei einem durch den elektrischen Leiter EL fließenden Strom I und dem durch diesen Strom I verursachten Magnetfeld in Bewegungsrichtung D ergebende Komponente des Magnetfeldes B ist als Hx bezeichnet als Funktion der Position x in Bewegungsrichtung D in dem Graphen G skizziert. Erkennbar ist, dass sich das Mag- netfeld Hx in der Bewegungsrichtung D ändert, so dass sich bei einer Bewegung der Mess-Spulc L in der Beweyungsrichrung D eine Änderung des die Mess-Spule L durchsetzende magnetischen Flusses ergibt. Hierdurch wird in der Mess-Spule L eine Spannung induziert, die eine Messgröße für den durch den elektrischen Leiter EL fließenden Strom I darstellt.Clarification of the embodiment of the method according to the invention. Shown here is a perspective view of a substantially corresponding to the figure 1 arrangement, for better illustration, the carrier of the measuring coil L has been omitted. It can be seen that the measuring coil L is moved between a forward and a return conductor in the form of the legs of a U-shaped electrical conductor EL, wherein the direction of movement D is again indicated by a corresponding arrow. The component of the magnetic field B resulting in a current I flowing through the electrical conductor EL and the magnetic field caused by this current I in the movement direction D is sketched as Hx as a function of the position x in the direction of movement D in the graph G. It can be seen that the magnetic field Hx changes in the direction of movement D, so that a change in the magnetic flux passing through the measuring coil L occurs when the measuring coil L moves in the locking direction D. As a result, in the measuring coil L a Voltage induces, which is a measure of the current flowing through the electrical conductor EL current I.
Um eine möglichst große • Signalamplitude der induzierten Span- nung zu erzielen, wird die Schwingungsfrequenz des mikro- elektromechanischen Oszillators vorzugsweise im Bereich einiger Kilohertz bis in dem Megahertz Bereich gewählt werden. Dabei ist zu beachten, dass die Schwingungsfrequenz des mik- roelektromechanischen Oszillators vorzugsweise derart gewählt wird, dass die spektralen Anteile des elektrischen Stromes I im Bereich der Betriebsfrequenz des mikroelektromechanischen Oszillators vernachlässigt werden können. Hierzu wird vorteilhafterweise eine Bandpassfilterung mit geringer Bandbreite vorgesehen und die Betriebsfrequenz des mikroelektromecha- nischen Oszillators deutlich größer, d.h. beispielsweise um einen Faktor 10 bis 100 größer, gewählt als die im Spektrum des elektrischen Stromes I mit signifikanter Amplitude auftretenden maximalen Frequenzen. Dies bedeutet, dass sofern kein Gleichstrom sondern ein elektrischer Wechselstrom mit einer Frequenz von beispielsweise 1 kHz erfasst werden soll, hierfür vorzugsweise ein mikroelektromechanischer Oszillator verwendet wird, dessen Betriebsfrequenz im Bereich von zumindest 10 kHz liegt.To achieve the maximum • Signal amplitude of the induced voltage, the oscillation frequency of the micro-electro-mechanical oscillator is preferably selected in the range of several kilohertz to in the megahertz range. It should be noted that the oscillation frequency of the microelectromechanical oscillator is preferably chosen such that the spectral components of the electric current I in the range of the operating frequency of the microelectromechanical oscillator can be neglected. For this purpose, bandpass filtering with a low bandwidth is advantageously provided, and the operating frequency of the microelectromechanical oscillator is significantly greater, ie, for example, a factor 10 to 100 greater than the maximum frequencies occurring in the spectrum of the electric current I having a significant amplitude. This means that if no direct current but an alternating electrical current with a frequency of, for example, 1 kHz is to be detected, this preferably a micro-electro-mechanical oscillator is used, the operating frequency is in the range of at least 10 kHz.
Figur 3 zeigt ein Ausführungsbeispiel der erfindungsgemäßenFIG. 3 shows an exemplary embodiment of the invention
Anordnung mit einem Ausführungsbeispiel des erfindungsgemäßen mikroelektromechanischen Systems. Dargestellt ist ein mikro- elektromechanisches System MEMS, das aus einem Anker A, einer Mess-Spule L, zwei ersten Elektroden ETDl sowie einer zweiten Elektrode ETD2 besteht. Darüber hinaus ist in der in Figur 3 gezeigten Anordnung neben dem mikroelektroτnρ<-haniεchcn System MEMS ein U-förmiger elektrischer Leiter EL dargestellt. An dieser Stelle sei generell darauf hingewiesen, dass der elektrische Leiter EL grundsätzlich auch Bestandteil der ei- gentlichen Messvorrichtung sein kann. In diesem Fall wird ein zu messender Strom somit in den elektrischen Leiter EL eingeleitet, der in diesem Fall in der Messvorrichtung üblicherweise mit einem festen Abstand zum mikroelektromechanischen System MEMS angeordnet sein wird. Alternativ hierzu kann jedoch der elektrische Leiter EL auch Bestandteil einer beliebigen anderen Komponente sein, in welchem Fall die eigentliche Messvorrichtung den elektrischen Leiter EL somit nicht mit umfasst.Arrangement with an embodiment of the microelectromechanical system according to the invention. Shown is a micro-electro-mechanical system MEMS, which consists of an armature A, a measuring coil L, two first electrodes ETDl and a second electrode ETD2. Moreover, in the arrangement shown in Figure 3 next to the mikroelektroτn ρ <-haniεchcn System MEMS a U-shaped electrical conductor EL is illustrated. It should generally be pointed out at this point that the electrical conductor EL is basically also a component of the can be the actual measuring device. In this case, a current to be measured is thus introduced into the electrical conductor EL, which in this case will usually be arranged in the measuring device at a fixed distance from the microelectromechanical system MEMS. Alternatively, however, the electrical conductor EL may also be part of any other component, in which case the actual measuring device thus does not include the electrical conductor EL.
Bei dem in Figur 3 dargestellten mikroelektromechanischen System MEMS wird durch den Anker A sowie die ersten Elektroden ETDl und die zweite Elektrode ETD2 ein mikroelektromecha- nischer Oszillator gebildet. Dabei ist der schwingfähige Teil des Oszillators, der durch die zweite Elektrode ETD2 gegeben ist, an dem Anker A aufgehängt. Zwischen der zweiten Elektrode ETD2 und den jeweiligen ersten Elektroden ETDl befindet sich jeweils ein Luftspalt SP, dessen Breite üblicherweise im Mikrometerbereich liegen wird. Durch ein zyklisches Anlegen entsprechender Potenziale auf den Elektroden ETDl, ETD2 wird aufgrund wirkender elektrostatischer Kräfte ein mechanisches Schwingen der zweiten Elektrode ETD2 bewirkt, wobei die Bewegungsrichtung in Figur 3 durch den dargestellten Doppelpfeil angedeutet ist. Entsprechend der Darstellung der Figur 3 ist eine Mess-Spule L, die in dem dargestellten Beispiel wiederum zwei Windungen aufweist, auf der zweiten Elektrode ETD2 befestigt, so dass mittels des mikroelektromechanischen Oszillators die Mess-Spule L derart bewegt wird, dass aufgrund der Bewegung der Mess-Spule L in dem durch den elektrischen Strom I bewirkten Magnetfeld des elektrischen Leiters EL eine zyklische Änderung des die Mess-Spule L durchsetzenden rr.αgneti- schen Flusses bewirkt wird. Hierdurch wird, wie zuvor bereits erläutert, eine Spannung in der Mess-Spule L induziert, die durch entsprechende Mittel erfasst werden und aus der der in dem elektrischen Leiter EL fließende Strom I ermittelt werden kann .In the microelectromechanical system MEMS shown in FIG. 3, a microelectromechanical oscillator is formed by the armature A as well as the first electrodes ETD1 and the second electrode ETD2. In this case, the oscillatable part of the oscillator, which is given by the second electrode ETD2, suspended from the armature A. Between the second electrode ETD2 and the respective first electrodes ETD1 there is in each case an air gap SP whose width will usually be in the micrometer range. By cyclically applying corresponding potentials on the electrodes ETD1, ETD2, a mechanical oscillation of the second electrode ETD2 is caused due to acting electrostatic forces, wherein the direction of movement is indicated in Figure 3 by the double arrow shown. 3, a measuring coil L, which again has two turns in the illustrated example, is mounted on the second electrode ETD2, so that the measuring coil L is moved in such a way by means of the microelectromechanical oscillator that due to the movement of the Measuring coil L in which caused by the electric current I magnetic field of the electrical conductor EL a cyclic change of the measuring coil L passing through rr.αgneti- rule flow is effected. As a result, as already explained above, a voltage is induced in the measuring coil L, which voltage is detected by corresponding means and from which the voltage in the electric conductor EL flowing current I can be determined.
Es sei darauf hingewiesen, dass im Rahmen des erfindungsgemä- ßen mikroelektromechanischen Systems selbstverständlich auch mikroelektromechanische Oszillatoren verwendet werden können, die nach einem anderen als einem elektrostatischen Prinzip arbeiten. Darüber hinaus sei vorsorglich darauf hingewiesen, dass selbstverständlich auch eine Mess-Spule mit nur einer oder auch mehr als zwei Windungen verwendet werden kann.It should be noted that within the scope of the microelectromechanical system according to the invention it is of course also possible to use microelectromechanical oscillators which operate on a principle other than an electrostatic principle. In addition, it should be noted as a precaution that, of course, a measuring coil with only one or even more than two turns can be used.
Vorzugsweise kann das in Figur 3 dargestellte mikroelektromechanische System zusätzlich einen kapazitiven Spannungsmesser zum Erfassen der Spannung des elektrischen Leiters EL aufwei- sen. Ein entsprechendes mikroelektromechanisches System zur kapazitiven Spannungsmessung ist beispielsweise aus der zuvor bereits erwähnten WO 2005/121819 Al bekannt. Vorzugsweise ist der Spannungsmesser hierbei an den mikroelektromechanischen Oszillator angekoppelt, so dass die durch den Oszillator be- wirkte Bewegung nicht nur die Änderung des die Mess-Spule durchsetzenden magnetischen Flusses, sondern darüber hinaus auch eine im Rahmen der Spannungsmessung erforderliche Kapazitätsänderung bewirkt. Hierdurch wird vorteilhafterweise auf besonders einfache, kompakte und kostengünstige Art und Weise ein mikroelektromechanisches System zur Leistungsmessung, d.h. ein Wattmeter, bereitgestellt.Preferably, the microelectromechanical system shown in FIG. 3 may additionally have a capacitive voltmeter for detecting the voltage of the electrical conductor EL. A corresponding microelectromechanical system for capacitive voltage measurement is known, for example, from the previously mentioned WO 2005/121819 A1. In this case, the voltage meter is preferably coupled to the microelectromechanical oscillator, so that the movement effected by the oscillator not only causes the change of the magnetic flux passing through the measuring coil, but also causes a change in capacitance required in the context of the voltage measurement. This advantageously provides a microelectromechanical system for measuring performance, i.e., in a particularly simple, compact and cost-effective manner. a wattmeter, provided.
Entsprechend den vorstehend beschriebenen Ausführungsbeispielen weisen das erfindungsgemäße mikroelektromechanische Sys- tem sowie das erfindungsgemäße Verfahren insbesondere denAccording to the exemplary embodiments described above, the microelectromechanical system according to the invention and the method according to the invention have in particular the
Vorteil auf, dass auf vergleichsweise einfache Art und Waise eine galvanisch getrennte sowie vielseitig einsetzbare Erfassung einer Messgröße für den durch den elektrischen Leiter fließenden Strom ermöglicht wird. Insbesondere dadurch, dass hierbei der zu messende, durch den elektrischen Leiter fließende elektrische Strom nicht selbst durch das mikroelektro- mechanische System zu fließen braucht, sind das mikroelektro- mechanische System sowie das Verfahren darüber hinaus, insbe- sondere auch hinsichtlich ihrer Anwendbarkeit bei vergleichsweise hohen Stromstärken, vorteilhafterweise besonders leistungsfähig. Advantage that in a comparatively simple way and orphan galvanically isolated and versatile usable detection of a measure of the current flowing through the electrical conductor current is made possible. In particular, by the fact that In this case, the electrical current to be measured, which flows through the electrical conductor, does not have to flow itself through the microelectromechanical system, the microelectromechanical system and the method are furthermore particularly advantageous, in particular also with regard to their applicability at comparatively high current intensities powerful.
Claims
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/EP2008/008359 WO2010034334A1 (en) | 2008-09-26 | 2008-09-26 | Method and microelectromechanical system for capturing a measurement variable for an electric current flowing through an electrical conductor, and an arrangement |
| AT09163275T ATE533169T1 (en) | 2008-09-26 | 2009-06-19 | METHOD AND DEVICE FOR MONITORING A SWITCHING PROCESS AND RELAY ASSEMBLY |
| EP09163275A EP2169700B1 (en) | 2008-09-26 | 2009-06-19 | Method and device for monitoring a switching procedure and relay component group |
| EP09164759A EP2169830A3 (en) | 2008-09-26 | 2009-07-07 | Device for converting an analogue signal into a digital signal |
| US12/559,819 US20100082268A1 (en) | 2008-09-26 | 2009-09-15 | Method and apparatus for monitoring a switching process and relay module |
| CN200910176196.9A CN101685137B (en) | 2008-09-26 | 2009-09-25 | Method and apparatus for monitoring interrupting process, and relay assembly |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/EP2008/008359 WO2010034334A1 (en) | 2008-09-26 | 2008-09-26 | Method and microelectromechanical system for capturing a measurement variable for an electric current flowing through an electrical conductor, and an arrangement |
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| WO2010034334A1 true WO2010034334A1 (en) | 2010-04-01 |
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| PCT/EP2008/008359 Ceased WO2010034334A1 (en) | 2008-09-26 | 2008-09-26 | Method and microelectromechanical system for capturing a measurement variable for an electric current flowing through an electrical conductor, and an arrangement |
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| WO (1) | WO2010034334A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| IT202300019944A1 (en) * | 2023-09-27 | 2025-03-27 | St Microelectronics Int Nv | INTEGRATED SYSTEM IN PACKAGE FOR ELECTRIC CURRENT MONITORING BASED ON MAGNETIC FIELD |
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| EP0816861A2 (en) * | 1996-06-25 | 1998-01-07 | Siemens Aktiengesellschaft | Apparatus for measuring magnetic fields |
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| EP0816861A2 (en) * | 1996-06-25 | 1998-01-07 | Siemens Aktiengesellschaft | Apparatus for measuring magnetic fields |
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| IT202300019944A1 (en) * | 2023-09-27 | 2025-03-27 | St Microelectronics Int Nv | INTEGRATED SYSTEM IN PACKAGE FOR ELECTRIC CURRENT MONITORING BASED ON MAGNETIC FIELD |
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| ATE533169T1 (en) | 2011-11-15 |
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