AC powered fluid meter

Abstract

A fluid meter comprising a generator (12), a metrology sensor (4), a control block (6), a power supply block (10) coupled to the generator (12) and configured to supply energy to the control block (6), wherein the power supply block (10) comprises a first supply path (14) comprising at least one primary cell (16) and a second supply path (20) connected to the generator (12) comprising a capacitor (C1) and a first switch (S1) configured to selectively couple the capacitor (C1) and the generator (12), the power supply block (10) comprising a second switch (S2) configured to selectively couple the first supply path (14) or the second supply path (20) to the control block (6), the power supply block (10) further comprising a current sensor (26) determining a current measurement, the first switch and the second switch being monitored as a function of a state of charge of the capacitor, the state of charge of the capacitor being determined as a function of the current measurement.

Description

TECHNICAL FIELD

[0001] The present invention belongs to the technical field of fluid meters. A fluid meter is a metering device configured to perform metering measurements in a fluid circulation pipeline. The fluid can be a liquid, such as for example water or oil, or a gas, such as for example a gas mixture of hydrocarbons consisting mainly of methane, such as natural gas. The metering measurements are usually volumes or flow rates related to the fluid circulating in the pipeline. BACKGROUND

[0002] In order to acquire some metering data about the fluid circulation in the pipeline, fluid meters are usually used to generate and provide metering measurements. In order to acquire these metering measurements, fluid meters have been developed equipped with means for transmitting information related to said metering data. These communication means can be adapted for remote communication and allow for example wired or wireless transmission of this information. The communication means can also have in the display a plurality of information organized according to a menu. In all cases, these meters require an electrical supply. However, the meters can be placed in locations that do not allow easy connection to the electrical network, so they must have an autonomous electrical supply without connection to the electrical network.

[0003] The simplest way to autonomously power a fluid meter is to equip it with a primary cell, i.e. an energy storage element that cannot be recharged in situ. However, the energy storage capacity must be sufficient to allow an electrical supply for a long period of time, usually 20 years, which leads to the use of very large primary cells. In addition, the useful life of the primary cell depends on the electrical consumption of the meter, which can significantly reduce the useful life of the primary cell, in any case the primary cell will eventually be depleted and must be replaced, an operation that requires monitoring the state of the primary cell.

[0004] To overcome these drawbacks, it has been proposed to replace the primary cell with a rechargeable battery, for example powered by a generator configured to be driven by the fluid circulation in the pipeline and to generate electrical power to recharge the battery.

[0005] However, the potentially intermittent nature of the fluid circulation requires the battery to have a considerable electrical storage capacity, which leads to a large volume and high cost. In addition, the irregularities of the fluid circulation process can increase the incomplete charge-discharge cycles of the battery, thus reducing its performance over time.

[0006] Patent application WO2015150247 describes a method for operating electronic devices carried by a device and a device equipped with a turbine able to be driven in rotation by a fluid flow and means for detecting at least a determined angular position of the turbine, an electric pulse being delivered each time the turbine passes this angular position. A pulse counter can count the delivered pulses. A current generator can power the electronic devices. An electric energy accumulator can be charged by the current generator and power the electronic devices. However, such an accumulator only works when current is generated. To provide power supply during turbine downtime, a primary cell can replace the accumulator, the size of which must always be increased as the downtime period is frequent or prolonged. SUMMARY

[0007] The present invention thus aims to propose a fluid meter equipped with a power supply having a long service life, a smaller volume and greater reliability.

[0008] To this end, the present invention proposes a fluid meter configured to perform a metering measurement in a fluid circulation duct and to transmit information relating to said metering data, the fluid meter comprising:

[0009] - a generator configured to be driven by the circulation of the fluid in the fluid duct and to generate electricity,

[0010] - at least one metering sensor configured to perform a metering measurement in the fluid duct,

[0011] - a control block configured to receive the metering measurement results and to transmit information relating to said metering data,

[0012] - a power supply block coupled to the generator and configured to supply energy to the control block, wherein the power supply block comprises a first supply path comprising at least one primary cell and a second supply path connected to the generator, the second supply path comprising a capacitor and a first switch configured to selectively couple the capacitor and the generator, the power supply block further comprising a second switch configured to selectively couple the first supply path or the second supply path to the control block,

[0013] The power supply block further comprises a current sensor configured to determine a current measurement representative of the intensity of the charging or discharging current of the capacitor,

[0014] The first switch and the second switch are configured to be monitored by the control block as a function of the charging state of the capacitor, the charging state of the capacitor being determined by the control block as a function of said current measurement.

[0015] As the first supply path and the second supply path alternate to ensure the supply of power, it is possible to permanently supply the control block while only requiring a low storage capacity, a small volume, a low cost, a long service life of the primary cell.

[0016] Preferably, to facilitate the supply of power by the capacitor, at least when the generator generates electricity, the control block is configured to: a) when the state of charge becomes greater than a high threshold, open the first switch and position the second switch on the second supply path, and b) when the state of charge of the capacitor becomes less than a low threshold, close the first switch and position the second switch on the first supply path.

[0017] The invention advantageously complements the following different features taken separately or according to different possible combinations thereof:

[0018] - the high threshold is greater than or equal to 80% of the maximum state of charge and the low threshold is less than or equal to 10% of the maximum state of charge;

[0019] - the control block is configured to update the previous state of charge at each time step with a multiple of the square of the current intensity;

[0020] - the control block is configured to update the previous state of charge at each time step with the product of said current intensity and the voltage between the first terminal of the capacitor and the reference potential between the first switch and the second switch, said voltage decreasing the voltage across the resistor as a function of the current intensity;

[0021] - the state of charge is expressed as a proportion of the maximum energy storage capacity of the capacitor;

[0022] - said gauge comprises a resistor in series between the capacitor and the reference voltage and the measurement of the current is determined by the voltage across the resistor;

[0023] - one end of the capacitor is coupled to one end of the first switch and to one end of the second switch;

[0024] - the transmission of information related to the gauge data is performed by displaying on a screen and / or by the transmission of said gauge data;

[0025] - the first supply path and the second supply path are independent;

[0026] - the primary cell is a non-rechargeable electrical energy storage element or its configuration in the power supply block makes it impossible to charge within this power supply block. BRIEF DESCRIPTION OF DRAWINGS

[0027] Other features, objects and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and should be read in conjunction with the attached drawings, in which:

[0028] -Figure 1 is a schematic overview of a fluid meter according to a possible embodiment of the application;

[0029] - Figure 2 is a block diagram of a fluid meter according to a possible embodiment of the application. DETAILED DESCRIPTION

[0030] Figure 1 A fluid meter is shown, which is configured to perform a metering measurement in a fluid circulation pipe 2 and to communicate information related to the metering data. Typically, the fluid circulation pipe 2 is part of the fluid meter, as the fluid meter comprises a conduit portion in which fluid circulates, which conduit portion is integrated into a fluid circulation network. In order to perform the metering measurement, the fluid meter comprises at least one metering sensor 4, which is configured to perform the metering measurement in the fluid pipe 2. The metering sensor 4 is preferably arranged in the fluid pipe 2. The type of the metering sensor 4 depends on the technology used to perform the measurement, which can be ultrasonic, electromagnetic, thermal or Coriolis technology. In the shown example, two ultrasonic transducers are arranged in the pipe facing each other, in order to implement the metering measurement by ultrasound in a known manner. The result of the metering measurement is typically a volume or flow rate related to the fluid circulating in the pipe 2, which is derived from the data collected by the metering sensor(s) 4.

[0031] The fluid meter comprises a control block 6, which comprises at least one processor and one memory, and which is configured to receive the result of the metering measurement from the metering sensor 4 and to communicate information related to the metering data. Typically, the metering sensor 4 can be connected to the control block 6, e.g. by a wired link, and transmit the result of the metering measurement to the control block 6.

[0032] The communication of the information related to the metering data is performed by displaying on a screen and / or by transmission. The fluid meter can have a display screen 7, in which the information related to the metering data can be displayed. The fluid meter can be equipped with a human-machine interface, such as buttons, so that the display of such information related to the metering data can be caused and the display can be changed, e.g. by making it possible to scroll its different types on the display screen 7. The information related to the metering data can be transmitted to the outside of the fluid meter, preferably by a wireless link, in which case the fluid meter can comprise an antenna and any other known elements that make it possible to establish a remote communication with the fluid meter.

[0033] Preferably, the fluid meter conforms to EU Directive 2014 / 32 / EU on measuring instruments, more commonly known as the Measuring Instruments Directive (MID). In particular, the fluid meter must be able to permanently transmit information related to the metrological data. Similarly, the fluid meter must be able to perform metrological measurements at any time. Therefore, the fluid meter must have a permanent power supply.

[0034] For this purpose, the fluid meter includes: a power supply block 10 configured to permanently supply power to a control block 6; and a generator 12 configured to drive and generate electricity through the circulation of fluid in the pipe, the power supply block 10 being coupled to the generator 12.

[0035] At least a portion of the generator 12 is disposed in the pipe 2 in contact with the fluid to extract mechanical energy and convert it into electricity. Typically, the generator 12 is a turbine, preferably with blades, integrating a rotor and stator. The generator 12 provides electricity available outside the pipe. Preferably, the generator 12 is disposed downstream of the metering sensors 4 in the fluid pipe along the direction of fluid circulation so as not to interfere with these metering measurements.

[0036] The power block 10 includes two distinct and independent paths: a first supply path 14 including at least one primary battery 16 and a second supply path 20 connected to the generator 12. A "primary battery" refers to an energy storage element, such as a non-rechargeable battery, or one whose configuration within the power block 10 makes recharging impossible within the power block 10. Typically, the first supply path 14 includes only the primary battery 16. The primary battery 16 preferably has a maximum energy storage capacity of less than 100 Wh, such as, for example, 30.6 Wh (8.5 Ah based on 3.6 V) or 68.4 Wh (19 Ah based on 3.6 V).

[0037] The second supply path 20 includes a capacitor C1 and a first switch S1, which is configured to selectively couple or decouple the capacitor C1 and the generator 12. The capacitor C1 preferably has a maximum energy storage capacity E greater than or equal to 0.5 Wh. max And even more preferably greater than or equal to a maximum energy storage capacity E of 0.8Wh. max For example, capacitor C1 can deliver a charge of 0.222 Ah at 3.6V. Capacitor C1 is preferably a supercapacitor. Typically, capacitor C1 can be a hybrid-layer supercapacitor or a hybrid-layer capacitor (HLC), but it can also be a supercapacitor capable of providing a maximum energy storage capacity E greater than or equal to 0.5 Wh. max Any type of supercapacitor. Preferably, the maximum energy E of capacitor C1 is... max It is at least one-twentieth of the maximum energy of the primary cell.

[0038] The first switch S1 is arranged between the capacitor C1 and the generator 12. The first switch S1 is controlled by the control block 6 for its opening and closing. The first switch S1 is preferably a relay, for example an electromechanical relay.

[0039] The second supply path 20 can comprise different current shaping elements in series between the generator 12 and the first switch S1, and for example a rectifier 22 in series with a voltage regulator 24. The power supply block 10 further comprises a current sensor 26 configured to determine a current measurement representative of the intensity of the charging or discharging current of the capacitor C1. In the example shown, the first end of the capacitor C1 is connected between the first switch S1 and the second switch S2 (at the connection point where the voltage V between said connection point and the reference potential to which the resistor R1 is connected is known by design), and the second end of the capacitor C1 is connected in series with one end of a resistor R1, the resistor R1 being connected to a reference potential (for example ground) via its other end. The measurement related to the current flowing through the resistor R1, typically the voltage V across the resistor R1, is taken by the current sensor 26 r Once the resistance value of the resistor R1 is known, the measurement of the signed current I (positive during charging and negative during discharging) can be derived from this voltage V r The current sensor 26 can thus be a voltmeter. The resistance value of the resistor R1 can be low and for example less than 800 mΩ.

[0040] The current sensor 26 transmits its measurement to the control block 6. Preferably, the current measurement is an average value of intensity values taken during a time period, typically during a time step.

[0041] The power supply block 10 further comprises a second switch S2 configured to selectively couple the first supply path 14 or the second supply path 20 to the control block 6, thus selecting whether the control block 6 is powered by the first supply path 14 or by the second supply path 20.

[0042] The first switch S1 and the second switch S2 are controlled by the control block 6 for their state: opening or closing of the first switch S1, selection of the supply path by the second switch S2. When the first switch S1 is closed and the second switch S2 connects the control block 6 to the primary cell 16, then the primary cell 16 powers the control block 6, the capacitor C1 is coupled to the generator 12 and recharges, storing electrical energy. When the first switch S1 is open and the second switch S2 connects the control block 6 to the capacitor C1 of the second supply path 20, the control block 6 is powered by the capacitor C1, the primary cell 16 is not loaded.

[0043] The first switch S1 and the second switch S2 are configured to be monitored by the control block 6 as a function of the state of charge of the capacitor C1, determined by the control block 6 as a function of the current measurements. The control block 6 is in fact configured to determine the state of charge (SoC) of the capacitor C1 as a function of the measurements of the current. More specifically, the state of charge is updated at each time step as a result of the measurement of the current. For example, during the charging of the capacitor C1, the state of charge (SoC) of the previous instant is increased by a multiple of the square of the current intensity, more specifically, by the product of the current intensity I and the voltage intensity V minus the voltage across the resistor R1 as a function of the current intensity.

[0044] Preferably, the state of charge is expressed as a proportion of the maximum energy storage E max of the capacitor C1. It follows the energy expression, i.e. (V-R1.I).I, divided by E max , where R1 is the resistance value of the resistor R1, and thus SoC(t+T) = SoC(t) + T.((V-R1.I).I / E max . During the discharging of the capacitor C1, the state of charge (SoC) of the previous instant is decreased by a multiple of the square of the current, i.e. by the product of the current intensity and the voltage intensity V minus the voltage across the resistor R1 as a function of the current intensity (also negative value), in this case negative, thus SoC(t+T) = SoC(t) + T.(V-R1.I).I / E max . Preferably, the time step T is less than 10 seconds. The time step T is preferably greater than 0.1 seconds. For simplicity, the time step here is 1 second, which simplifies the determination of the state of charge:

[0045] - during charging: SoC(t+T) = SoC(t) + (V-R1.I).I / E max ,

[0046] - during discharging: SoC(t+T) = SoC(t) + (V-R1.I).I / E max ,

[0047] If the state of charge is sufficiently high, the second switch S2 connects the second supply path 20 to allow the capacitor C1 to power the control block 6 through the second supply path 20. Otherwise, the second switch S2 connects the first supply path 14 to allow the recharging of the capacitor C1 while the primary cell 16 of the first supply path 14 powers the control block 6. The control block 6 is configured to at least when the generator 12 generates electricity:

[0048] - when the state of charge becomes greater than a high threshold, the first switch S1 is opened and the second switch S2 is positioned on the second supply path 20,

[0049] - when the state of charge of the capacitor CI becomes lower than a low threshold, closing the first switch SI and positioning the second switch S2 on the first supply path 14.

[0050] The estimation of the state of charge from the current measurements is more accurate than other methods, for example based on the voltage across the capacitor CI, and thus allows to fully exploit the storage capacity of the capacitor CI.

[0051] Figure 2 An example of a fluid meter operation chart is shown, which illustrates the variations of the states of the first switch SI and of the second switch S2, with the different steps implemented by the control block 6. In a default state S00, for example before the installation of the fluid meter, the second switch S2 is positioned on the primary cell 16, that is to say connecting the control block 6 to the first supply path 14. The first switch SI is preferably closed. The state of charge of the capacitor CI can be zero or very low. The default state can be maintained, for example, until a non-zero charging current is detected by the current sensor 26.

[0052] In a first step S01, the first switch SI is closed, connecting the capacitor CI to the generator. The second switch S2 is positioned on the primary cell 16. The capacitor CI can then be charged with electrical energy. In a second step S02, the charging current is measured via the current sensor 26, and the state of charge is updated based on the measurements of the charging current. More specifically, as mentioned above, the state of charge is increased by a multiple of the charging current intensity squared. Then, a test S03 is performed to check whether the state of charge is greater than a high threshold by comparison between the current state of charge and the high threshold. The high threshold is used to check that the capacitor CI is sufficiently charged, and thus corresponds to a state of charge close to the maximum energy E max that the capacitor can store. Typically, the high threshold is at least 80% of the maximum energy E max , and preferably at least 90% of the maximum energy E max .

[0053] If this is not the case, the control block 6 returns to the second step S02 to continue charging the capacitor CI. If the charge state is greater than the high threshold, the control block 6 controls the opening of the first switch SI and the passage of the second switch S2 to the capacitor CI in step S04, thus coupling the control block 6 and the second supply path 20. The control block 6 is now powered by the discharging capacitor CI and is no longer powered by the primary cell 16. The opening of the first switch SI makes it possible to decouple the capacitor CI and the generator 12, thus avoiding possible electrical disturbances. During the discharge of the capacitor CI, at each time step, the step S05 of measuring the discharge current and updating the charge state is performed. More particularly, as mentioned above, the charge state is reduced by a multiple of the square of the discharge current intensity. A test S06 is then implemented to check whether the charge state is less than this low threshold by comparison between the current charge state and the low threshold. The low threshold serves to check that the capacitor CI has discharged sufficiently and thus corresponds to a charge state close to the minimum. Generally, the low threshold is less than 10% of the maximum energy E max and for example less than or equal to 5% of E max .

[0054] If the charge state is greater than the low threshold, the capacitor CI continues to discharge and a new step S05 of measuring the discharge current and updating the charge state is performed. If the charge state is less than or equal to the low threshold, this means that the capacitor CI has discharged sufficiently and must now be recharged. The control block 6 then therefore returns to step S01, closing the first switch SI and switching the second switch S2 to the first supply path 14 on the primary cell 16.

[0055] As can be seen in this method, the control block 6 is configured to maximize the use of the capacitor CI and to save the primary cell 16. The primary cell 16 is then only used to allow the recharge of the capacitor CI. Thanks to the permanence of the power supply, even in the absence of fluid circulation, the fluid meters are able to deliver them by, for example, displaying information relating to the metering data. It should be noted that the charging time of the capacitor CI is inversely proportional to the rotational speed of the turbine. Given the low energy requirements of the control block 6, it is easy to ensure that the recharge time of the capacitor CI is much shorter than the discharge time of the capacitor CI. The capacitor CI can ensure the majority of the power supply to the control block 6. The primary cell 16, which has a smaller load, can be chosen with a lower energy storage capacity, thus reducing the volume and the cost while maintaining or increasing its service life.

[0056] The application is not limited to the embodiments described and represented in the attached drawings. Modifications remain possible without departing from the scope of protection of the application, in particular from the point of view of the constitution of the various technical features or by substitution of technical equivalents.

Claims

1. A fluid meter configured to perform a metrological measurement in a fluid circulation pipe and to transmit information related to metrological data, the fluid meter comprising: - a generator (12) configured to be driven by the fluid circulation in the fluid pipe (2) and to generate electricity, - at least one metrological sensor (4) configured to perform a metrological measurement in the fluid pipe (2), - a control block (6) configured to receive the metrological measurement result and to transmit information related to the metrological data, - a power supply block (10) coupled to the generator (12) and configured to supply the control block (6) with energy, wherein the power supply block (10) comprises a first supply path (14) comprising at least one primary cell (16) and a second supply path (20) connected to the generator (12), the second supply path (20) comprising a capacitor (CI) and a first switch (SI) configured to selectively couple the capacitor (CI) and the generator (12), the power supply block (10) further comprising a second switch (S2) configured to selectively couple the first supply path (14) or the second supply path (20) to the control block (6), the power supply block (10) further comprising a current sensor (26) configured to determine a current measurement representative of the intensity of the charging or discharging current of the capacitor (CI), the first switch (SI) and the second switch (S2) being configured to be switched by the control block (6) as a function of the state of charge of the capacitor (CI) determined by the control block (6) as a function of the current measurement.

2. The fluid meter of claim 1, wherein, the control block (6) being configured to at least when the generator (12) generates electricity: - open the first switch (SI) and position the second switch (S2) on the second supply path (20) when the state of charge becomes greater than a high threshold, - close the first switch (SI) and position the second switch (S2) on the first supply path (14) when the state of charge of the capacitor (CI) becomes less than a low threshold.

3. The fluid meter of claim 2, wherein, the high threshold being greater than or equal to 80% of the maximum state of charge and the low threshold being less than or equal to 10% of the maximum state of charge.

4. The fluid meter of any one of claims 1-3, wherein, the control block (6) being configured to update the previous state of charge at each time step with a multiple of the square of the current intensity.

5. The fluid meter of any one of claims 1-3, wherein, the state of charge being expressed as a proportion of the maximum energy storage of the capacitor (CI).

6. The fluid meter according to any one of claims 1-3, comprising a resistor (Rl) in series between the capacitor (CI) and a reference voltage, and the measurement of the current is determined as a function of the voltage across the terminals of the resistor (Rl).

7. The fluid meter of claim 6, wherein, The control block (6) is configured to update at each time step the previous state of charge with the product of a current intensity and a voltage intensity (V) between a first terminal of the capacitor (C1) and a reference potential, the first terminal of the capacitor (C1) being between a first switch (S1) and a second switch (S2), the voltage intensity being reduced by the voltage across a resistor (R1) according to the current intensity.

8. The fluid meter of any one of claims 1-3, wherein, A terminal of the capacitor (C1) is coupled to a terminal of the first switch (S1) and to a terminal of the second switch (S2).

9. The fluid meter of any one of claims 1-3, wherein, The transmission of information related to the metering data is performed by displaying on a screen and / or by transmission of the metering data.

10. The fluid meter of any one of claims 1-3, wherein, The first supply path (14) and the second supply path (20) are independent.

11. Fluid meter according to any one of claims 1-3, wherein the primary cell (16) is a non-rechargeable or its configuration in the power supply block (10) makes it impossible to charge (10) the electrical energy storage element within the power supply block.

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