ES2826948T3 - Device to receive electrical energy wirelessly - Google Patents

Abstract

A device for wirelessly receiving electrical energy to be transferred from a source (2) of alternating current by electromagnetic coupling by means of an electrically conductive transmitter loop (3) connected to this source, said device comprising - at least one receiver loop (4, 20, 21) electrically conductive configured to receive electrical energy from said source in the form of an induced current therein by means of an electromagnetic coupling when placed near said electrically conductive transmitter loop, - at least one capacitor (5, 24, 25) connected within said receiver loop (4, 20, 21) to be charged with electrical energy by means of said induced current in the receiver loop, - a system (9) configured to allow a part of the induced current in said receiver loop flows only in one direction to the capacitor to charge the capacitor and does not flow in the opposite direction and discharge the co ncapacitor, and - a capacitance (12) connected to the receiver loop to tune it to a certain frequency, characterized in that said at least one capacitor (5, 24, 25) is connected inside the receiver loop by having opposite poles of it directly connected to the receiver loop (4, 20, 21) in a first position (8) therealong, because said system comprises at least one rectifier member (10, 22, 23) connected within the receiver loop in a second position ( 11) along the same spacing with respect to said first position and configured to allow a rectified part of the induced current in the receiver loop to flow only in one direction through it, and because said capacitance (12) is connected within the receiver loop in said second position (11).

Description

DESCRIPTION

Device to receive electrical energy wirelessly

Technical field of the invention

The present invention relates to a device for wirelessly receiving electrical energy to be transferred from an alternating current source by electromagnetic coupling by means of an electrically conductive transmitter loop connected to this source, said device comprising at least one conductive receiver loop of electricity configured to receive electrical energy from said source in the form of current induced therein by means of electromagnetic coupling when placed near said electrically conductive transmitter loop, at least one capacitor connected within said receiver loop to be charged with electrical energy by means of said induced current in the receiver loop, a system configured to allow a part of the induced current in said receiver loop to flow only in one direction to the capacitor to charge the capacitor and not flow in the opposite direction and discharge the capacitor, yu A capacitance connected to the receiver loop to tune it to a certain frequency.

A device of this type can be used in any type of equipment that wants to be supplied wirelessly with electrical energy, that is, that wants to be energized by so-called remote powering. Such equipment in the form of a beacon to be arranged between two rails of a railway track to transmit data by means of antennas mounted underneath railway vehicles passing through the beacon is just one example of this type of equipment.

The particular application of the invention in a beacon will be set forth below to illustrate the invention and the problems to be solved by it without thereby restricting the invention thereto.

Railways use beacons to send information from the track to passing trains. There are many ways to do this, and a method for this can be found in the standard ERTMS, European Rail Traffic Management System. The link of the beacon is based on electromagnetic coupling, that is, the beacon located on the ground and the ATP (Automatic Train Protection) antenna located on the train constitute an air transformer as long as the antenna is located above (or very close to ) of the beacon. The link is bidirectional and the frequencies used are short wave radio. The downlink is used to transmit energy to the beacon, which is consequently received by the device defined in the introduction. The uplink is used to transmit data to the train, and the transmitter of said uplink is powered by the electrical energy received by said device. Document AU 2013206087 B2 is a document that describes the remote powering of a beacon in general.

Since the contact distance between a standard size beacon located on the ground and the ATP antenna located on the train is approximately 1 m, this means that the duration of contact is highly dependent on speed. Modern trains can travel at 100 m / s, which means they need 10 ms to move 1 m. This means that the time allowed for the beacon to be remotely powered by the train and for the beacon to send its ATP telegram turns out to be approximately 10 ms. This is a technical challenge. Railroad companies would like to have smaller beacons and at the same time allow higher train speeds on their tracks, which means that the contact time for such remote powering will be reduced to levels that require improvements in the efficiency of the railways. beacons to meet these demands.

Background of the technique

Figure 1 schematically illustrates the structure of a known device of the type defined in the introduction as used in a beacon. The number 100 illustrates an alternating current source arranged on board a rail vehicle. This source generates an alternating current in an electrically conductive transmitter loop 101 located on board the vehicle. When this transmitter loop 101 passes over an electrically conductive receiver loop 102 located in said beacon, the alternating current in the transmitter loop 101 will generate by means of electromagnetic coupling a current in the receiver loop. The transmit loop 101 and the receive loop 102 do not have to be the same shape and size to achieve this. The induced current in the receiver loop 102 is rectified through the use of a diode bridge 103-106, which forms a system configured to allow a rectified portion of the induced current in the receiver loop to flow only in one direction to a capacitor 107 connected to the receiver loop so that it is charged with electrical energy by means of the induced current in the receiver loop. The load (DC voltage) across capacitor 107 can then be used to power other electrical devices, such as a microprocessor. Furthermore, a capacitance in the form of a capacitor 108 is connected to the receiver loop to tune it to the frequency of the transmitters of the rail vehicles that pass the beacon.

Once the remote power supply by electromagnetic coupling starts, the time it takes to charge the capacitor 107 to a certain voltage level decides when a transmitter located on the beacon can send its ATP telegram to the vehicle antennas. passing railroad. This then also decides at what speed a train can pass through the beacon and still receive said telegram with important information from it. Therefore, it is my wish to be able to shorten the charging time of said condenser to allow higher speeds of trains and / or smaller beacons with respect to beacons provided with a known device shown in Figure 1.

Such a device is known from EP 0242906 A1.

Compendium of the invention

The present invention is defined by the features of the independent claims.

The object of the present invention is to provide a device of the type defined in the introduction which is improved with respect to the already known device by means of a reduced response time with respect to that of the known device.

According to the invention, this object is obtained by providing said device with the features listed in the characterizing part of the attached patent claim 1.

Consequently, said capacitor is connected within the receiver loop by having opposite poles thereof directly connected to the receiver loop in a first position along it, and the system comprises at least one rectifier member, such as a rectifier diode, connected within the receiver loop at a second position along it spaced from the first position and configured to allow a rectified portion of the induced current in the receiver loop to flow only in one direction therethrough. Furthermore, the capacitance for said tuning is connected inside the receiver loop at said second position.

The voltage across said capacitor will be higher than in the known device in which there will be a voltage drop across each diode, since the diode bridge has been replaced by said rectifier member connected within the receiver loop. This means that the time it will take to charge the capacitor to a predetermined level will be shortened, so that in the case of the device used in a beacon, a transmitter in the beacon powered by the capacitor will be able to send a message to the passing train sooner. , allowing it to pass through the beacon with a higher speed than in a beacon fitted with a known device. In this way, a device according to the invention will shorten the critical activation time of the beacon.

According to an embodiment of the invention, said first and second positions are in opposite positions along said receiver loop, which means that the rectifier member and the tuning capacitance are arranged on one side of the receiver loop and the capacitor a charging on the opposite side, which keeps the receiving device balanced and less sensitive to stray capacitances than an unbalanced receiving device.

According to another embodiment of the invention, said tuning capacitance is connected in parallel to said rectifier member, and the rectifier member is, according to another embodiment, preferably a rectifier diode. The tuning capacitance can then be formed by the inherent capacitance of the diode or it can be provided by a capacitor connected in parallel to the diode.

According to another embodiment of the invention, the general shape and size of the receiver loop defined by the parts of the receiver loop between said first and second positions are substantially identical to the shape and size of said electrically conductive transmitter loop from which the receiver loop is configured to receive electrical energy, which can increase the efficiency of the remote power supply by electromagnetic coupling, and then it is advantageous that the general shape of the receiver loop is symmetrical with the rectifier member and the capacitor to be charged on opposite sides.

According to another embodiment of the invention, the device comprises a plurality of said superimposed electrically conductive receiver loops, and a rectifier member connected within a single receiver loop is configured to allow the induced current in that receiver loop to flow only in the direction therethrough opposite to what is configured to allow a rectifier member located in a neighboring receiver loop. This means that one of every two receiver loops will be active and charging the capacitor in question during a half-period of the alternating current of said source, and that the neighboring receiver loops will be active in that sense during the other half-period of the alternating current, so that the capacitors are charged all the time and a DC source made up of these capacitors will be more efficient than in the case of a single receiver loop, since the losses with respect to the power of the network will be less than for a device that only have a receiving loop. Also, the currents in adjacent receiver loops will be out of phase, which means that the harmonics in the induced currents will also be out of phase and counteract each other. This means that the harmonics in the eddy currents are greatly reduced, which is a very desirable property.

According to another embodiment of the invention, all said at least one capacitor of the receiver loops are interconnected to form together an assembly that stores electrical energy, which consequently results in an efficient DC source to be used by equipment in which the device according to the invention is integrated.

According to another embodiment of the invention, said interconnected capacitors are connected in parallel with each other.

According to another embodiment of the invention, said interconnected capacitors are connected in series to provide a voltage of said set formed by a sum of the voltages across all said capacitors. The chosen way to interconnect said capacitors will depend on the type of load to be connected to them. A series connection can be selected when there is a need to generate large voltages, and a parallel connection when large currents are of greater importance.

According to another embodiment of the invention, the number of receiver loops is even, which results in an optimal reduction of harmonics created in the device.

The invention also relates to a beacon according to the preamble of the appended claim directed thereto and comprising a device according to the present invention for wirelessly receiving electrical energy from a transmitter in an antenna of a railway vehicle. The advantages of providing a beacon with a device according to the present invention are clearly apparent from the above description of the device according to the invention and the embodiments thereof.

Additional advantages and advantageous features of the invention will be apparent from the description provided below.

Brief description of the drawings

With reference to the accompanying drawings, a specific description of exemplary embodiments of the invention is provided below.

In the drawings:

Figure 1 is a simplified view that illustrates very schematically the structure of a known device of the type to which the present invention belongs,

Figures 2-4 are views corresponding to Figure 1 of devices according to a first, a second and a third, respectively, embodiment of the invention, and

Figure 5 is a graph showing the DC voltage across the charged capacitor versus time obtained by electromagnetic coupling for the devices shown in Figures 1, 2 and 3.

Detailed description of embodiments of the invention

In Figure 2 there is shown a device 1 for wirelessly receiving electrical energy to be transferred from an alternating current source 2 by electromagnetic coupling by means of an electrically conductive transmitter loop 3. This device has an electrically conductive receiver loop 4 configured to receive electrical energy from said source 2 in the form of an induced current therein by means of electromagnetic coupling when placed near said electrically conductive transmitter loop 3. A capacitor 5 is connected within the receiver loop by having opposite poles 6, 7 thereof directly connected to the receiver loop at a first position 8 along it. A system 9, configured to allow a rectified part of the induced current in the receiver loop to flow only in one direction towards the capacitor 5 to charge the capacitor and not flow in the opposite direction, which would discharge the capacitor, is formed by a diode 10. This diode is connected within the receiver loop at a second position 11 along the same spaced from the first position. A capacitor in the form of a capacitor 12 is connected within the receiver loop in parallel with the diode 10 in said second position to tune the receiver loop to a certain frequency.

The diode bridge in the known device shown in Figure 1 has been replaced here by a single diode 10. This means that the voltage across the charged capacitor will be higher, since, for example, in the case of a voltage across of it 4 V, the voltage across the capacitor of the device of Figure 1 would only be about 3 V due to a voltage drop of the order of 0.2-0.5 V across each diode. This higher voltage shortens the charging time required to reach a predetermined voltage level, such as 3 V, of the capacitor, to allow it to be used as a source to power, for example, a microprocessor. However, the charging of a capacitor will only take place in one out of every two half-periods of the induced current, which lengthens the charging time. By moving diode 10 and tuning capacitor 12 to an opposite side of receiving loop 4, the receiving device will remain balanced and less sensitive to stray capacitances. Furthermore, the elimination of the diode bridge means that, for a given device size, the receiver loop 4 can be made larger, resulting in a more efficient transfer of power and data while interacting with the transmitter loop 3, or the device. it can be made smaller without making the receiver loop smaller. In this way, in the case of a beacon provided with such a device, the beacon can be made smaller and the capacity of the beacon can still be maintained with regarding transfer efficiency and can be improved with regard to the start time of such data transfer.

In Figure 3 a device according to a second embodiment of the invention is shown. This device has two superimposed electrically conductive receiving loops 20, 21. A diode 22, 23 connected within a single receiver loop is configured to allow the induced current in that receiver loop to flow only in the opposite direction through it with respect to what is configured to allow a diode located in the other loop. receiver. This means that each receiver loop will be active for "its" half period. The capacitors 24, 25 of the two receiver loops are interconnected and connected in parallel. In this way, charging continues all the time, not just for one out of every two half-periods, so that a more efficient DC source is created than that of the embodiment shown in Figure 2. This receiving device is also balanced. As mentioned above, the currents induced in the receiving loops are always out of phase, so the harmonics will also be out of phase and counteract each other and for that reason greatly reduced.

Figure 4 illustrates a device according to a third embodiment of the invention that differs from that shown in Figure 3 by having the capacitors 24, 25 connected in series, which means that the voltage obtainable through the DC source obtained by means of the two capacitors it will be doubled with respect to that of the embodiment shown in Figure 3. The type of interconnection of the capacitors that is selected, in parallel or in series, can be based on the need to generate large voltages or large currents.

As an example of a load that can be supplied by the DC voltage of the charged capacitor / capacitors, Figures 2-4 show an electrically conductive transmitter 26 and transmitter loop 27 for data transmission in case of having the receiver device included in a beacon.

The graph in Figure 5 illustrates the DC voltage U across the DC source formed by the capacitor (capacitors in Figure 3) charged versus time t for the three designs shown in Figure 1, Figure 2 and in Figure 3. It is clearly observed that the charging process will be slower and that the obtainable voltage will be lower for the known device shown in Figure 1 (a), while the devices shown in Figure 2 (b) and in Figure 3 (c) they behave in a similar way with respect to the charging time and the obtainable tension. If we assume that a DC voltage of 2.9 V is needed to start a microprocessor powered by this voltage source, the time required for this for the device shown in Figure 1 will be t1 and for the devices shown in Figures 2 and 3 will be t2, which is about half as long. This means, in the case of having such a device on a beacon, the possibility of allowing considerably higher train speeds and still guaranteeing an adequate transfer of electrical energy and messages between a train and the beacon.

Although not shown in the figures, it is noted that each receiver loop can have more than one turn, that is, it can be a multi-turn loop, and then include in a suitable turn a connection to the components shown on the left in the figures. figures and include in a suitable loop a connection to the components shown to the right in the figures. These two suitable turns can be the same or different depending on balance issues.

Claims (13)

1. A device for wirelessly receiving electrical energy to be transferred from a source (2) of alternating current by electromagnetic coupling by means of an electrically conductive transmitter loop (3) connected to this source, understanding said device • at least one electrically conductive receiver loop (4, 20, 21) configured to receive electrical energy from said source in the form of an induced current therein by means of an electromagnetic coupling when placed near said conductive transmitter loop electricity, • at least one capacitor (5, 24, 25) connected within said receiver loop (4, 20, 21) to be charged with electrical energy by means of said induced current in the receiver loop, • a system (9) configured to allow a part of the induced current in said receiver loop to flow only in one direction to the capacitor to charge the capacitor and not flow in the opposite direction and discharge the capacitor, and • a capacitance (12) connected to the receiver loop to tune it to a certain frequency, characterized in that said at least one capacitor (5, 24, 25) is connected within the receiver loop by having opposite poles of it directly connected to the receiver loop (4, 20, 21) in a first position (8) along it, because said system comprises at least one rectifier member (10, 22, 23) connected within the receiver loop in a second position (11) to along the same spacing with respect to said first position and configured to allow a rectified part of the induced current in the receiver loop to flow only in one direction through it, and because said capacitance (12) is connected within the loop receiver in said second position (11). A device according to claim 1, characterized in that said first (8) and second (11) positions are in opposite positions along said receiver loop (4, 20, 21). A device according to claim 1 or 2, characterized in that said tuning capacitance (12) is connected in parallel to said rectifier member (10, 22, 23). 4. A device according to any of the preceding claims, characterized in that said rectifier member is a rectifier diode (10, 22, 23). A device according to claim 4, characterized in that said tuning capacitance is an inherent capacitance of said rectifier diode or is provided by a capacitor (12) connected in parallel to said diode (10, 22, 23). A device according to any of the preceding claims, characterized in that said device further comprises the electrically conductive transmitter loop (3), the electrically conductive transmitter loop (3) having a shape and a size, therefore that the general shape and size of the receiver loop (4, 20, 21) defined by parts of the receiver loop between said first (8) and second (11) positions are substantially identical to the shape and size of the conductive transmitter loop (3) of electricity from which the receiving loop is configured to receive electrical energy. A device according to claim 6, characterized in that said general shape of the receiver loop (4, 20, 21) is symmetrical with the rectifier member (10, 22, 23) and the capacitor (5, 24, 25) to load on opposite sides. A device according to any of the preceding claims, characterized in that it comprises a plurality of said electrically conductive receiving loops (20, 21) superimposed, and in that a rectifying member (22, 23) connected within a loop Individual receiver is configured to allow induced current in that receiver loop to flow only in the opposite direction through it with respect to what is configured to allow a rectifier member in a neighboring receiver loop. A device according to claim 8, characterized in that all said at least one capacitor (24, 25) of the receiver loops are interconnected to form together an assembly that stores electrical energy. A device according to claim 9, characterized in that said interconnected capacitors (24, 25) are connected in parallel with each other. A device according to claim 9, characterized in that said interconnected capacitors (24, 25) are connected in series to provide a voltage of said set formed by a sum of the voltages across all said capacitors. 12. A device according to any of claims 8-11, characterized in that the number of receiver loops (20, 21) is even. 13. A beacon to be placed between the two rails of a railway track to transmit data to antennas mounted under rail vehicles that pass through the beacon, said beacon comprising • an electrically conductive receiver loop (4, 20, 21) configured to receive electrical energy by electromagnetic coupling from a transmitter located on said rail vehicle antennas when they pass through the beacon, • a transmitter (26) configured to be powered by the electrical energy received by the receiver loop, and • a conductive transmitter loop (27) configured to be powered by said transmitter to transmit data to said antennas of railway vehicles that pass through the beacon, characterized in that it comprises a device (1) according to any of the preceding claims for wirelessly receiving electrical energy from said transmitter.