ELECTRICAL VOLTAGE MEASURING DEVICE USING AN MICROELECTROMECHANICAL SYSTEM AND OPTICAL INTERFEROMETER INTERACTION

Abstract

An electrical voltage values measuring device having at least one microelectromechanical device comprising a first electrode connectable to an anode of an electrical voltage source and a second electrode connectable to a cathode of the electrical voltage source, wherein the microelectromechanical device is configured to receive an electrical voltage from the electrical voltage source causing a deviation of the first electrode, associated with the electrical voltage, wherein the deviation causes a distance variation between the first electrode and the second electrode, and an optical processor that comprises a laser and an optical sensor.

Claims

1. An electrical voltage measuring device, comprising: at least one microelectromechanical device comprising a first electrode configured to be connected to an anode of an electrical voltage source and a second electrode configured to be connected to a cathode of said electrical voltage source, wherein the microelectromechanical device is configured to receive an electrical voltage from the electrical voltage source causing a displacement of the first electrode associated with said electrical voltage, wherein said displacement causes a variation of distance between the first electrode and the second electrode; and an optical processor comprising a laser and an optical sensor, the optical processor configured to: project using the laser a light beam through a laser light injection point on the first electrode; detect with the optical sensor reflections of the light beam, wherein a distance variation between the first electrode and the laser light injection point generates a variation of at least one reflection of the light beam; obtain interference patterns based on the light beam and the at least one reflection of the light beam; and calculate a value of the electrical voltage applied to the first electrode and the second electrode based on the interference patterns.

2. The electrical voltage measuring device according to claim 1, further comprising: at least one optical fiber connected to the optical processor, wherein one end of the optical fiber comprises the laser light injection point, and wherein the optical fiber is configured to transmit the light beam and reflections of the light beam.

3. The electrical voltage measuring device according to claim 2, further comprising: a circuit board wherein at least the one end of the optical fiber comprising the laser light introduction point is integrated into the PCB.

4. The electrical voltage measuring device according to claim 2, wherein the optical fiber is a multicore fiber with a plurality of cores configured to transmit the light beam and the reflections of the light beam, and an optical multiplexer comprising an output connected to the optical processor.

5. The electrical voltage measuring device according to claim 2, wherein the optical fiber is a monocore fiber with a plurality of optical terminals configured to transmit the light beam and the reflections of the light beam and an optical multiplexer comprising an output connected to the optical processor, and wherein the optical multiplexer is spatial.

6. The electrical voltage measuring device according to claim 1, wherein the first electrode is configured as a conductive cantilever and comprises a cantilever end, wherein the cantilever end is a free end, wherein the laser is configured to project the light beam to an area of the cantilever end, and wherein the deviation of the first electrode comprises a structural deviation ?Z(V) of the cantilever end at least partially parallel to the light beam.

7. The electrical voltage measuring device according to claim 1, wherein the first electrode comprises a first conductive sheet comprising a center suspended above a first surface of the microelectromechanical device, the first electrode being fixed only at its ends, wherein the second electrode comprises a second conductive sheet, wherein the first conductive sheet is above the second conductive sheet, wherein the laser is configured to project the light beam onto the first conductive sheet at a distance L between the laser light injection point and the first conductive sheet, and wherein a deviation of the first electrode comprises a distance variation ?L(V) between the first conductive sheet and the laser light injection point.

8. The electrical voltage measuring device according to claim 1, wherein the microelectromechanical device comprises a capacitive MEMS.

9. A system comprising: the electrical voltage measuring device according to claim 1; and at least one electrical voltage source.

10. The system according to claim 9, wherein the electrical voltage source is a fuel cell or a battery.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To complement the description being made and in order to help a better understanding of the characteristics of the electrical voltage measuring device according to the present invention, some schematic figures are attached as an integral part of said description where, for illustrative purposes and not limiting, the following has been represented:

[0029] FIG. 1 shows a first example of an electrical voltage measuring device according to the present invention. It comprises a single sensor.

[0030] FIG. 2 shows an electrical voltage measuring device according to the present invention comprising a string of microelectromechanical devices.

[0031] FIG. 3 shows a second example of an electrical voltage measuring device according to the present invention.

[0032] FIG. 4 shows a top view of the second example of the electrical voltage measuring device shown in FIG. 3.

[0033] FIG. 5 shows a sectional view of the second example of the electrical voltage measuring device shown in FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] FIG. 1 shows a first example of an electrical voltage measuring device (1000) according to the present invention, comprising a single sensor.

[0035] The device (1000) comprises a microelectromechanical device (120), in particular a MEMS powered by an electrical voltage source (110), in particular, a fuel cell whose voltage is to be measured. The MEMS comprises a first electrode (A) (or mobile electrode) and a second electrode (B) (or fixed electrode) connected to an anode (x) and a cathode (y) of the electrical voltage source (110), respectively. The electrical voltage applied to the electrodes causes a structural deviation ?Z(V) of the first electrode (A) of the MEMS. Said structural deviation ?Z(V) can be detectable and measured by optical means, in particular, by an optical interferometry system. The sensor comprises a circuit board, PCB (150), on which the MEMS is established. The MEMS is configured to receive a charging electrical voltage from the electrical voltage source (110) causing the structural deviation AZ (V) of the first electrode (A) associated with said charging voltage.

[0036] The electrical voltage measuring device (1000) also comprises an optical processor (140) connected to an optical fiber (130). The optical fiber (130) may be integrated into the PCB (150). The optical processor (140) may comprise different elements depending on the configuration of the device (1000). In this particular embodiment, the optical processor (140) comprises a laser (140a) configured to project a light beam through a laser light injection point on the first electrode (A) through the optical fiber (130) connected to the optical processor (140) and an optical sensor (140b) configured to detect the light beam reflected at the fiber-air interface, as well as the light beam reflected on the first electrode (A), where the reflections may vary due to the structural deviation ?Z(V) of the first electrode (A).

[0037] The photonic part of the device (1000) is formed by an interferometric cavity (130a), the optical fiber (130) and the optical processor (140) that comprises the laser (140a) and the optical sensor (140b). The optical processor (140) is the reading unit of the interferometric cavity (130a). The optical processor (140) is configured to capture or detect through the optical fiber means (130) the reflections of the light beam emitted by the laser (140a) forming interference patterns. The interference patterns based on the light beam and its reflections can vary based on the structural deviation ?Z(V) of the first electrode (A). From the variation of the interference patterns, the value of the electrical charging voltage of the device sensor (1000) can be derived. Thus, through the optical processor (140), and since the wavelength of the light beam is very short, small changes can be detected in the differences in the optical paths (distance traveled) between the light beam coming from the laser (140a) and its reflection (since the differences produce notable changes in the interference pattern).

[0038] As can be seen in FIG. 1, for this particular embodiment, the first electrode (A) is configured as a conductive cantilever that comprises a free end or cantilever end (A). The laser (140a) is configured to project the light beam through a laser light injection point over an area of cantilever end (A). The structural deviation ?Z(V) of the first electrode (A) includes the deviation of the cantilever end (A). The laser light injection point may be included in one end of the optical fiber (130).

[0039] As can be seen in FIG. 1, the anode (x) and cathode (y) terminals of the fuel cell are connected to the first electrode (A), configured as a conductive cantilever, and to a second electrode (B) in the MEMS, respectively. When the fuel cell applies a voltage to the MEMS, the electrostatic forces caused by said voltage act on the conductive cantilever, causing a structural deviation thereof, ?Z(V), equivalent to the deviation of the end of the cantilever (A) and this being proportional to the difference in potential or voltage applied by the voltage source in the MEMS. Thus, connecting the anode (x) and the cathode (y) of a fuel cell to the conductive cantilever and the second electrode (B), an attractive force between both causes the structural deviation ?Z(V) of the end of the cantilever (A) that can be accurately measured through optical interferometry. The structural deviation AZ (V) can be correlated with the voltage applied to the MEMS, achieving interferometry patterns through the optical processor (140) that vary based on the voltage differential applied by the fuel cell.

[0040] The optical fiber (130) is aligned to project a light beam through a laser light injection point located at the end of the optical fiber (130) in an area of the end of the cantilever (A). Said light beam and the reflection at the end of the fiber (fiber-air interface) constitute the interferometric cavity (130a) and its response is guided by the optical fiber (130) to the optical processor (140), as can be seen in FIG. 1. In particular, the response of the interferometric cavity (130a) is read in the optical processor (140), since the interference patterns vary based on the deviation of the end of the cantilever (A).

[0041] FIG. 2 shows the scalability property of the electrical voltage measuring device (1000) according to the present invention. FIG. 2 shows a string of MEMS connected to their respective electrical voltage sources (110) and interrogated by a single optical processor (140). The optical fiber (130) comprises a plurality of optical terminals (130c) configured to detect the light beams and their reflections in each of the MEMS, as well as an optical multiplexer (130d) (which may be a spatial optical multiplexer) connecting the optical processor (140) on one side and the MEMS string on the other. In another example, the optical fiber is a multicore fiber with a plurality of cores configured to transmit the light beam and reflections of the light beam. In this particular embodiment, a plurality of optical terminals (130c) are used on the same optical fiber (130), which advantageously reduces the amount of wiring and simplifies the installation and implementation of the device (1000) compared to other existing devices in the state of the art.

[0042] FIG. 3 shows another embodiment of the electrical voltage measuring device (1000) according to the present invention. FIG. 3 shows a second configuration where the first electrode (A) comprises a first conductive sheet and the second electrode (B) comprises a second conductive sheet connectable to the anode (x) and the cathode (y) of the electrical voltage source (110). In this second configuration, the first conductive sheet (first electrode) is established on a first surface of the microelectromechanical device (120) and has a fixed position. The second conductive sheet (second electrode (B)), is suspended above the first electrode (A) at a distance X. This second electrode (B) has its two ends fixed to the MEMS structure, however, its central part can move based on the electrical voltage applied between the two electrodes (A, B), due to the electrostatic attraction (or repulsion) force that is generated when the electrical voltage is applied between the two electrodes.

[0043] Like the example of FIG. 1, for the embodiment of FIG. 3, the laser (140a) is configured to project a light beam onto (optionally, the center of) the second conductive sheet (second electrode (B)) suspended at a distance L between the optical fiber termination (130) and the first conductive sheet. The optical fiber (130) is connected to the optical processor (140) and configured to capture the reflections of the light beam towards the optical processor (140).

[0044] The laser (140a) is configured to project the light beam onto the first conductive sheet, suspended, (which can be seen in FIG. 4 in a top view). The center of the first conductive sheet (first electrode (A)) will undergo a displacement based on the applied electrical voltage and where said displacement includes, for this particular embodiment, a distance variation ?L(V) between the first conductive sheet and the second conductive sheet.

[0045] The optical processor (140) is configured to obtain interferometry patterns based on the electrical voltage applied to the conductive sheets of the capacitive MEMS and that causes a distance variation ?L(V) between the conductive sheets. In the configuration of FIG. 3, when an electrical voltage is applied between the electrodes of the MEMS, the electrostatic attraction force acts on the electrodes causing the distance variation ?L(V) between both electrodes and the variation of distance between the first conductive sheet and the end of the optical fiber (130).

[0046] As can be seen in the zoom view of FIG. 3, the light beam emitted by the laser (140a) preferably falls on the center of the first conductive sheet (first electrode A), which is suspended. Both the light beam and the reflection of the light beam are guided to the optical processor (140) through the optical fiber (130). As in the configuration of FIG. 1, the optical processor (140), through the optical detector (140b) can accurately measure the distance variation ?L(V) between the end of the optical fiber (130) and the first conductive sheet (in based on the distance variation) and correlate said variation with the voltage output of the fuel cell.

[0047] In this configuration, the laser light beam (140a) hits the first conductive sheet at a distance L, it is reflected in the MEMS producing a reflection of the beam that is guided to the optical processor (140) by means of the optical fiber (130). The application of a voltage V causes a displacement of the first electrode (A) equivalent to a distance variation ?L(V) between the two conductive sheets. Accordingly, the distance between the end of the optical fiber (130) and the first electrode (A) is variable. The optical processor (140) functioning as an interrogator or interferometer can accurately measure the displacement of the MEMS moving electrode and the distance variation, such that:

FSR=c/[2*n*L]

FSR=c/[2*n*(L+?L(V))]

?FSR(V)=FSR?FSR [0048] where FSR is the free spectral range observed in the interference pattern obtained by the optical processor (140) at a distance L; [0049] where FSR is the free spectral range observed in the interference pattern obtained by the optical processor (140) at a distance L+?L (V); and [0050] where n is the refractive index of the first conductive sheet and c is the speed of light.

[0051] Thus, based on the variation of the free spectral range ?FSR(V), the voltage applied V by the electrical voltage source (110) to the MEMS can be derived.

[0052] As can also be seen in the zoom view of FIG. 3, a schematic representation of the light beam emitted (S) by the laser (140a) included in the optical processor (140) is shown. Using the optical sensor (140b) the interference patterns can be obtained based on: [0053] (1) A first reflection (R1) equivalent to the light beam reflected in the first conductive sheet (first electrode (A)) of the MEMS; and [0054] (2) A second reflection (R2) equivalent to the light beam reflected at the interface of the optical fiber (130) with the air. This second reflection (R2) occurs at the end of the optical fiber (130).

[0055] The optical fiber (130) is connected to the optical processor (140) and configured to capture the reflections of the light beam towards the optical processor (140): the first reflection (R1) and the second reflection (R2).

[0056] In this way, the interference patterns are obtained based on the light beam and its reflections, where the first reflection (R1) is affected by the geometric variations of the MEMS. Thus, the value of the voltage to be measured is obtained based on these interference patterns.

[0057] FIG. 4 shows a top view of the second example of the electrical voltage measuring device (1000) shown in FIG. 3, where the first electrode (120A) is a first conductive sheet established above a first surface of the MEMS. In FIG. 4 it can be seen how the center of the first conductive sheet (120A) is suspended above the first surface of the MEMS and above the lower electrode (120B). Said first conductive sheet is fixed to the first surface at its ends (400), but in its central part the conductive sheet is suspended over the first surface and above the lower electrode. In another example the first sheet is suspended by elastic means. The second electrode (120B) comprises a second conductive sheet established on a second surface of the microelectromechanical device (120), lower than the first conductive sheet.

[0058] FIG. 5 shows a sectional view of the second example of the electrical voltage measuring device shown in FIG. 4. In FIG. 5 it can be seen the microelectromechanical device (120), for example, a MEMS, comprising the first electrode (120A) which is a first conductive sheet established above a first MEMS surface. In FIG. 5 it can be seen how the center of the first conductive sheet (120A) is suspended above the first surface of the MEMS and above the lower electrode (120B). This first conductive sheet is fixed to the first surface at its ends, but in its central part the conductive sheet is suspended over the first surface and above the lower electrode (120B). The second electrode (120B) comprises a second conductive sheet established on a second surface of the microelectromechanical device (120), lower than the first conductive sheet. The microelectromechanical device (120) is established on the PCB board (150).

[0059] The systems and devices described herein may include a controller or a computing device comprising a processing and a memory which has stored therein computer-executable instructions for implementing the processes described herein. The processing unit may comprise any suitable devices configured to cause a series of steps to be performed so as to implement the method such that instructions, when executed by the computing device or other programmable apparatus, may cause the functions/acts/steps specified in the methods described herein to be executed. The processing unit may comprise, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof.

[0060] The memory may be any suitable known or other machine-readable storage medium. The memory may comprise non-transitory computer readable storage medium such as, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. The memory may include a suitable combination of any type of computer memory that is located either internally or externally to the device such as, for example, random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like. The memory may comprise any storage means (e.g., devices) suitable for retrievably storing the computer-executable instructions executable by processing unit.

[0061] The methods and systems described herein may be implemented in a high-level procedural or object-oriented programming or scripting language, or a combination thereof, to communicate with or assist in the operation of the controller or computing device. Alternatively, the methods and systems described herein may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the methods and systems described herein may be stored on the storage media or the device, for example a ROM, a magnetic disk, an optical disc, a flash drive, or any other suitable storage media or device. The program code may be readable by a general or special-purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein.

[0062] Computer-executable instructions may be in many forms, including modules, executed by one or more computers or other devices. Generally, modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Typically, the functionality of the modules may be combined or distributed as desired in various embodiments.

[0063] It will be appreciated that the systems and devices and components thereof may utilize communication through any of various network protocols such as TCP/IP, Ethernet, FTP, HTTP and the like, and/or through various wireless communication technologies such as GSM, CDMA, Wi-Fi, and WiMAX, is and the various computing devices described herein may be configured to communicate using any of these network protocols or technologies.

[0064] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.