• 专利附录
  • 专利说明
  • 权利要求
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    • 专利摘要:

    公开号:FR3017752A1
    申请号:FR1451192
    申请日:2014-02-14
    公开日:2015-08-21
    发明作者:Veronique Khun；Fabrice Seguin；Cyril Lahuec；Christian Person
    申请人:Telecom ParisTech；Institut Mines Telecom IMT；
    IPC主号:
    专利说明:

    [0001] Device for converting radiofrequency energy into direct current and corresponding sensor. FIELD OF THE DISCLOSURE The field of the invention is that of energy recovery. More specifically, the invention relates to a technique for converting radiofrequency energy to direct current or DC voltage, for example to supply electronic circuits. The invention finds particular applications in the field of the supply of wired or wireless sensors, for example in the field of textiles (sensors worn on people's clothing), medical (biomedical implants, pacemaker, thermometer, etc.) , weather (remote weather stations, thermometer, etc.), sports (heart rate monitor, accelerometer, oximeter, etc.), radio frequency identification (RFID), mobile telephony (recharging of battery, etc.), surveillance, etc. 2. Prior art The decrease in the consumption of electronic components has enabled the development of mobile applications, such as wireless sensors. Most of these sensors, or wireless sensor networks (WSN), such as those worn by the person (in English BSAN, for "Body Sensor Area Network") are powered by batteries / Battery. The RFID wireless sensors, which are the most commonly used, consume dozens of microwatts in standby mode and several hundred microwatts in active mode. Although significant progress has been made in recent years, batteries still have a limited lifetime and their implementation can be problematic depending on their accessibility and volume constraints (particularly for subcutaneous medical implants). ).
    [0002] We therefore seek to explore other alternatives to power these sensors, for example by recovering the available energy in the ambient environment. Thus, thermal gradients, mechanical vibrations, light waves or radiofrequency in particular, are potential sources of energy for the supply of these sensors. In particular, radiofrequency sources have the advantage of being ubiquitous in our daily lives, especially in urban areas. Indeed, a multitude of wireless communication standards has led to the proliferation of radio transmitters such as GSM (900 MHz, 1800 MHz), UMTS (2.1 GHz) and WiFi (2.4 GHz). Consequently, these radiofrequency energies, transmitted continuously by telecommunication networks, are made available over a wide frequency range.
    [0003] The goal of radiofrequency energy recovery is to convert energy from ambient radio frequency sources into DC voltage and current. The basic element ensuring this conversion is called RF-DC converter, rectifying antenna, or "rectenna" of the English "Rectifying antenna".
    [0004] FIG. 1 thus presents a schematic diagram of a radio frequency energy recuperator. According to this diagram, radiofrequency waves 11 are received by a reception antenna 12 and then converted into DC voltage and current by an RF-DC converter 13. The current thus generated can be used to supply a load 14, which represents for example a sensor to feed. More specifically, the RF-DC converter 13 comprises an input filter 131, also called radio frequency (RF) filter or high frequency filter (HF), a rectifier 132 and an output filter 133, also called DC filter. The input filter 131 is placed between the receiving antenna 12 and the rectifier 132. This is a low-pass filter which is used to block unwanted harmonics. Several types of rectifiers are possible depending mainly on the incident power and the frequency. In order to correctly choose a topology, a compromise between the load output voltage and the conversion efficiency must be made, as described in V.Kuhn's "A multi-tone RF energy harvester in body sensor area network context" document. , F.Seguin, C.Lahuec and C.Person, IEEE LAPC conference, Lougborough, November 2013.
    [0005] Several types of RF-DC converter have been proposed, adapted to receive radiofrequency energy on one or more frequency bands. Thus, it has been proposed radio frequency energy recovery circuits transmitted in a single frequency band, using a single rectenna. Note however that the functionality of such a rectenna is considerably degraded if the operating frequency is changed from the optimal resonant frequency. Thus, a disadvantage of these radiofrequency energy recovery circuits transmitted in a single frequency band, implementing a single rectenna, is that they are not adapted to the ambient environment, in which the dominant frequencies are different according to the place of use of the load (eg according to the location of the sensor).
    [0006] Radiofrequency energy recovery circuits transmitted in several frequency bands have also been proposed. Indeed, it has been demonstrated in particular that when several sources of radiofrequency energy emitting in different frequency bands are available in the ambient environment, the amount of energy harvested can be increased. Thus, as illustrated in FIG. 2, networks of rectennas have been proposed, in which several rectennas (operating at different frequencies) are put in parallel. The DC outputs of each rectenna are added together to increase the harvested power. A disadvantage of these radiofrequency energy recovery circuits transmitted in several frequency bands, implementing several rectennas in parallel, is that they require the implementation of a summation DC DC voltages provided by each frequency band. But this summation, if not properly performed, can drastically deteriorate the efficiency of the circuit. Several techniques have been proposed for implementing such a summation of DC DC voltages, using series or differential interconnection topologies.
    [0007] The combination of series rectifiers for performing the summation, according to a first structure illustrated in FIG. 3A, may have an RF / DC conversion efficiency higher than that of a single frequency band circuit. This is possible only if each branch of the structure is in operation, i.e. if radio frequency signals are received and processed on each branch of the structure. Indeed, if one of the frequencies is not present on the dedicated branch, this one is seen like a load for the rest of the circuit. It thus deteriorates the overall performance of the circuit. The use of Greinacher type rectifiers for summing, according to a second structure illustrated in FIG. 3B, makes it possible to add the DC outputs without interfering with each other. Indeed, the output of each rectifier is differential. On the other hand, a disadvantage of such a structure is that it requires a minimum incident power of -10 dBm for an architecture using two Greinacher type rectifiers. However, in an urban environment, the average power density of the frequency bands is lower, that is to say less than -10 dBm. Thus, this type of architecture is not adapted to the conversion of energy from ambient RF radio frequency sources for the supply of loads. There is therefore a need for a new radiofrequency energy recovery circuit transmitted in one or more frequency bands not having these disadvantages of the prior art. 3. DISCLOSURE OF THE INVENTION The invention proposes a new solution which does not have all of these disadvantages of the prior art, in the form of a radio frequency energy conversion device in direct current, receiving as input at least one radiofrequency signal and generating at output a direct current capable of supplying at least one load. According to the invention, such a conversion device comprises at least one conversion stage comprising: a radio frequency filtering module, connected to a first input node of the conversion stage, configured to filter one of said at least one radiofrequency signal ; a voltage shift module, connected between a second input node of the conversion stage, the radio frequency filtering module and an intermediate node of the conversion stage, configured to move a voltage present at the first node of the conversion stage; input to the intermediate node; a voltage rectification module, connected between the intermediate node, the second input node and an output node of the conversion stage, configured to rectify the voltage of the intermediate node and output a rectified voltage to the output node; the second input node being connected to either a reference voltage or the output node of another conversion stage, and the direct current being generated on the output node if the latter is not connected to a second input node of another conversion stage. The invention thus proposes a new device for the recovery of radiofrequency energy, making it possible in particular to supply electronic devices such as sensors. In particular, the conversion device according to the invention comprises one or more conversion stages. It is thus adapted to recover the radiofrequency energy transmitted in a single frequency band, by activating a single conversion stage (or if only one conversion stage is available), and to recover the radiofrequency energy transmitted in several frequency bands. by activating several conversion stages, one per frequency band. Note that the number of stages of conversion is not limited. When several conversion stages are activated, the proposed conversion device makes it possible in particular to ensure correct summation of the DC voltages supplied by each frequency band present. In particular, the proposed structure makes it possible to add the DC outputs of each conversion stage without interference with each other, even when certain stages are not active, i.e. does not receive a radiofrequency signal. In addition, the conversion device according to the invention requires a lower incident power than the devices of the prior art to be able to generate a DC current (or equivalent DC voltage) able to supply at least one load. According to a particular embodiment of the invention, the voltage shift module implements a first capacitor, connected between the filtering module and the intermediate node, and a first diode, connected in a forward direction between the second node of the invention. input and the intermediate node. The voltage rectification module implements a second capacitor, connected between the second input node and the output node, and a second diode, connected in a forward direction between the intermediate node and the output node. Thus, each conversion stage uses two diodes in parallel, mounted head to tail. Therefore, it suffices that one has sufficient power to exceed the threshold of a diode to be able to generate a DC current capable of supplying at least one load. By way of comparison, the use of Greinacher type rectifiers to recover radiofrequency energy transmitted in several frequency bands relies on the implementation of several diodes in series, requiring a much higher incident power to start the circuit. The conversion device according to the invention therefore operates with lower incident powers than the devices of the prior art. In addition, the conversion device according to the invention is based on the use of half as many components as the devices of the prior art, which implies lower production costs. According to a particular aspect of the invention, the components (diodes and capacitors) are surface mounted components (SMDs). An energy conversion device according to the invention is therefore easily achievable and / or detectable. According to one variant, these components can be integrated. Such a conversion device thus takes the form of an electronic circuit, which can be printed, integrated, etc. According to another particular characteristic of the invention, the first and second diodes have substantially identical values. Thus, within the same conversion stage, the two diodes connected in parallel, head to tail, have substantially identical threshold voltages. This makes it possible to obtain a symmetry at a conversion stage, optimizing the recovery. According to one variant, the diodes within the same conversion stage, or within the different conversion stages, have different threshold voltages. For example, the first and second diodes are Schottky diodes. Such diodes make it possible in particular to avoid the appearance of parasitic capacitances. Of course, any type of diode having a low threshold voltage can be used (eg PN junction diode, etc.). According to a particular characteristic of the invention, the conversion device comprises at least one antenna for receiving the radio frequency signal or signals. Such a device can indeed be used to recover the radiofrequency energy carried in the ambient air. For example, the conversion device comprises a single broadband receiving antenna. In this way, there is a more compact structure, nevertheless adapted to the reception of radio frequency signals available in several frequency bands. Alternatively, the receiving device comprises a separate receiving antenna for each conversion stage, each receiving antenna being adapted to receive a radio frequency signal in a given frequency band. In this case, each receiving antenna may have a narrow band. For example, the radiofrequency filtering module comprises a radio frequency filter belonging to the group comprising: a bandpass filter centered on the frequency 900 MHz; a bandpass filter centered on the 1800MHz frequency; a bandpass filter centered on the 2.1 GHz frequency; a bandpass filter centered on the 2.4GHz frequency. Such a conversion device is thus adapted to receive the GSM 900 MHz and / or GSM 1800 MHz and / or UMTS and / or Wi-Fi frequency bands. Of course, other frequency bands (from very low frequency to very high frequency) ) can be listened to to recover the radiofrequency energy of one or more radio frequency signals. According to another embodiment of the invention, the radio frequency signal or signals are received via a wire link. The presence of reception antennas is therefore optional. In this case, the radiofrequency signal (s) can be taken directly from the source. For example, the source may be a Livebox (registered trademark) set-top box. The energy conversion device according to the invention can be directly connected to this set-top box by a wired connection.
    [0008] The invention also relates to a sensor comprising data collection means and means for retrieving the collected data. According to the invention, such a sensor also comprises a device for converting radiofrequency energy into direct current as described above, receiving as input at least one radiofrequency signal and generating as output a direct current supplying this sensor.
    [0009] Such a sensor may of course include the various characteristics relating to the radio frequency energy conversion device in direct current according to the invention, which can be combined or taken in isolation. Thus, the characteristics and advantages of this sensor are the same as those of the conversion device and are not detailed further. 4. List of Figures Other features and advantages of the invention will appear more clearly on reading the following description of a particular embodiment, given as a simple illustrative and non-limiting example, and the accompanying drawings, among which: Figure 1, discussed in relation to the prior art, shows a block diagram of a radiofrequency energy recuperator; FIG. 2, also described in relation with the prior art, illustrates the recovery of energy over several frequency bands; FIGS. 3A and 3B show two examples of RF-DC converters used for energy recovery on several frequency bands according to the prior art; FIG. 4 illustrates the general principle of a device for converting radiofrequency energy into direct current according to the invention; FIGS. 5 and 6 show two examples of radio frequency energy conversion devices according to one embodiment of the invention; Figures 7 and 8 illustrate the performance of the invention; FIG. 9 illustrates an example of a sensor powered by a device for converting radio frequency energy into direct current according to one embodiment of the invention. 5. DESCRIPTION OF AN EMBODIMENT OF THE INVENTION 5.1 GENERAL PRINCIPLE OF THE INVENTION The general principle of the invention is based on a new device for converting radiofrequency energy into direct current (or equivalent to DC voltage). , receiving as input at least one radiofrequency signal and generating at output a direct current capable of supplying (at least) a load. The particular structure of the device according to the invention makes it possible in particular to recover the radiofrequency energy present on one or more frequency bands, and to provide a summation of the effective DC voltages when radiofrequency energy is recovered on several bands of frequency. In particular, the proposed device is formed by one or more conversion stages, each capable of processing a radio frequency signal received on a distinct frequency band. The differential output of each conversion stage allows lossless summation of the generated DC voltages.
    [0010] FIG. 4 illustrates more precisely the general principle of a conversion device according to the invention, in the form of an electronic circuit. Such a conversion device comprises at least one conversion stage 41 comprising: a radio frequency filtering module 411, connected to a first input node E1 of the conversion stage 41, configured to filter a radio frequency signal. Such a filtering module 411 comprises, for example, a band-pass filter centered on the frequency F1. It is used to transmit a maximum of power to the rest of the circuit in the desired frequency band, and to block the undesirable harmonics to enable an efficiency. optimal conversion; a voltage shifting module 412, connected between a second input node E2 of the conversion stage 41, the radio frequency filtering module 411, and an intermediate node A, configured to move a voltage present at the first node of the input E1 on the intermediate node A of the conversion stage 41; a voltage rectification module 413, connected between the intermediate node A, the second input node E2, and an output node B, configured to rectify the voltage of the intermediate node A and deliver a rectified voltage on the output node B of the conversion stage 41. In particular, it is noted that the second input node E2 is connected to either a reference voltage or to the output node of another conversion stage.
    [0011] For example, when the device comprises a single conversion stage, the second input node E2 is connected to a reference voltage, for example ground or a reference 1V. When the device comprises several conversion stages, the second input node E2 of the first stage is connected to a reference voltage and the second input nodes E2 of the other stages are connected to the output nodes B of the lower stages (the second one). input node of the second stage is connected to the output node of the first stage, the second input node of the ith stage is connected to the output node of the (i-1) th stage, etc. In addition, the current continuous circuit capable of supplying at least one load is generated on the output node B of the conversion stage if this output node is not connected to a second input node of another conversion stage. In other words, the direct current is generated on the output node of a conversion stage which is not connected to a second input node of another conversion stage, Figure 5 illustrates the architecture of the solution. proposed for a con version comprising i conversion stages referenced 51, 52 and 5i.
    [0012] Each conversion stage is composed of a filter module, a voltage shift module and a voltage rectification module as described above. The conversion device illustrated in FIG. 5 makes it possible to generate a direct current lm for supplying a load RL, connected between the output node Bi of the i-th conversion stage 5i and the second input node E2 (51) of the first conversion stage 51, which is connected to ground. More precisely, the first conversion stage 51 comprises two input nodes E1 (51) and E2 (51), an intermediate node A1, and an output node B1. The second input node E2 (51) is connected to a reference voltage, for example the mass. This first conversion stage 51 comprises a first filtering module 511, centered on the frequency F1. If Vrf is noted, 1 the AC voltage induced at the first input node E1 (51), at the input of the filtering module 511 , then the voltage shift module comprising the first capacitor C1,1 and the first diode D1,1 moves the voltage Vit1 to the intermediate node A1. Thereafter, the voltage rectification module comprising the second capacitor C2,1 and the second diode D2,1 rectifies the voltage at the intermediate node A1 to obtain a DC voltage DC at the output node B1, denoted Vout, 1. The second conversion stage 52 comprises two input nodes E1 (52) and E2 ( 52), an intermediate node A2, and an output node B2. The second input node E2 (52) is connected to the output node B1 of the first conversion stage 51. This second conversion stage 52 comprises a second filtering module 521, centered on the frequency F2. If Vrf, 2 is the AC voltage induced at the first input node E1 (52), at the input of the filtering module 521, then the voltage offset module comprises the first capacitor C1,2 and the first diode D1 , 2 moves the voltage Vrt2 to the intermediate node A2. Subsequently, the voltage rectification module comprising the second capacitor C2,2 and the second diode D2,2 rectifies the voltage at the intermediate node A2 to obtain a DC voltage DC to the output node B2, denoted Vout2. The i-th conversion stage 5i comprises two input nodes E1 (5i) and E2 (5i), an intermediate node Ai, and an output node Bi. The second input node E2 (5i) is connected to the output node B (i-1) of the conversion stage (i-1). This i-th conversion stage 5i comprises an i-th filtering module 5i1, centered on the frequency Fi. If Viti is noted the AC voltage induced at the first input node E1 (5i), at the input of the filter module 5i1, then the voltage shift module comprising the first capacitor C1, i and the first diode D1, i moves the voltage Viti to the intermediate node Ai. Subsequently, the voltage rectification module comprising the second capacitor C2, i and the second diode D2, i rectifies the voltage at the intermediate node Ai to obtain a DC voltage DC to the output node Bi, noted fout ,. According to the proposed example, the first conversion stage 51 is referenced to ground (second input node E2 (51) connected to ground) and the i-th conversion stage 5i is referenced with respect to (i-1 ) th conversion stage (second input node E2 (5i) connected to the output node of the conversion stage (i-1)). Each conversion stage therefore forms a rectifying or rectenna antenna. It will be noted that the first input nodes E1 (51), E1 (52), E1 (5i) of each conversion stage may each be connected to a separate reception antenna, able to receive a radio frequency signal in the frequency band associated with the conversion stage considered. As a variant, the first input nodes E1 (51), E1 (52), E1 (5i) of each conversion stage can be connected to a single antenna, for example a broadband antenna, capable of receiving radio frequency signals in the frequency bands associated with the different conversion stages. This defines a more compact structure than a structure based on the use of several receiving antennas "directives", each adapted to a specific frequency band. According to yet another variant, the first input nodes E1 (51), E1 (52), E1 (5i) are directly connected (by wire connection for example) to one or more sources generating a radiofrequency signal.
    [0013] In particular, it is noted that if one or more conversion stages are not powered by a voltage Viti, these stages are not disturbed the other conversion stages powered by a voltage Vit; thanks to the Vouti differential output of each conversion stage and the second capacitors C2i which maintain the DC level. The DC current IDC is generated on the output node Bi of the conversion stage i, since the output node Bi is not connected to a second input node of another conversion stage. The total voltage obtained VDc is the sum of the contributions Vout of the different conversion stages, as shown below. The proposed technical solution therefore makes it possible to have a wideband system and to add the DC voltages obtained for each frequency band without loss of output voltages with a low incident power, of the order of -30 dBm. Indeed, the invention requires two times less diodes than the implementation of a Greinacher type rectifier. In addition, it should be noted that the number of frequency bands, i.e. the number of conversion stages is not limited. 5.2 Analytical Expression of the Proposed Solution The following is an analytical expression of the proposed solution, in particular to demonstrate that the total voltage obtained VDc is the sum of the contributions Vout, i of the different conversion stages. To this end, it is considered that each conversion stage is composed of a filter module, a voltage shift module comprising a first capacitor and a first diode, and a voltage rectification module comprising a second capacitor and a second diode. It is assumed that the capacitors (capacitances) of the conversion device are perfect and their ideal operation: they let the radiofrequency signal pass and block the direct current. It is also assumed that the diodes of the same stage have similar threshold voltages and are of Schottky diode type, modeled by an exponential law. The current Id in the diodes is then written: ï / (1) exp V 'of 1, V T with: I a constant specific to the type of diode considered; V the threshold voltage of the considered diode; Vdiode the voltage across the diode considered. In equation (1), the term Vdiode representing the voltage across each diode can be written: Vrf cos (cot) (2) ydiode 1 / applied vrf 1 / applied V applied voltage applied to the diode holding The R series resistance of the diode can be expressed in the following form: 20 V applied = Vpola - R sI DC (3). It is assumed that the capacitances Ci act as decoupling capacitors: they prevent the direct current from circulating and have little effect on the incident wave of amplitude present at the input of each conversion stage, also called the input voltage. If all the diodes are identical, their static bias Vpok is calculated as a function of the DC voltage of the previous conversion stage. Thus, we have: 1 / polo -2 (yout, i-1 -1 / out, / (4) Vdiode, i -Vout, i-1- sI DC ± 1yrf, i1COS (C01 ") (5) Id = 1, 12 The calculation of the current passing through each diode can be carried out thanks to the Bessel functions which allow the exponential expansion: exp (xcos (wt)) = 80 (x) +21,87 (x) cos (ncot (6) Thus, one can isolate the continuous term from the current passing through the diodes: / V diode, i 1 d = Is exp V applied to ICOS (aer exp 1 / ATV))) V TI) Id 1 s exp " V applied jr +218 1 Vr f / o "n V T) ', ', T ', T Id = 1s exp cos (wt) -1 (7))) Thus, we have: = exp V In addition, it is possible to use the following approximate expression for 80: e 80 (x) - ixp (x) (9) VD-cx 10 The following expression is thus obtained for the current: ## EQU1 ## The equation (10) makes it possible to obtain a relationship connecting the point of polarization at the output of the conversion device at the amplitudes of the t In this way: V In 271-r VT ï / DC 2 -VT -1 -V) + RI (12) 2 out, is an incidental group V il DC DC DC DC DC DC DC DC DC DC DC ID ID ID ID ID ID ID ID ID ID ID DC rf, i Is where: / 1V r T VIrt 2TC rf 'i V / V ouci + V ln V o, i + R s V ° ut' i -1V + IV IT i (13) 2 TRIR 2 out The equation (13) is the analytic expression that describes the behavior of the conversion device. Indeed, it connects the parameters of the diode and the DC output voltage V to out ,, -1 the amplitude of the input voltage Vrfi of the i-th conversion stage. This expression confirms that the DC outputs of the different conversion stages (i.e. of the different rectennas) are correctly summed. 5.3 Simulation Results The implementation of conversion devices comprising either a conversion stage, two conversion stages or three conversion stages was simulated. The table below presents the input / output voltages obtained at the different nodes of the conversion device, based on the notations of FIG. 5: Vrf number, 1 (V) Vrf, 2 (V) Vrf , 3 (V) Vout, 1 (V) Vout, 2 (V) Vout, 3 (V) VDC (V) of stages 1 0.65 0.86 0.86 2 0.6 0.6 0.75 0.73 1.475 3 0.55 0.55 0.55 0.5 0.8 0.6 1.9 It can be seen that for a conversion device comprising two conversion stages each supplied with the same input voltage (Vrf , 1 = Vrf, 2), the total output voltage, VDC, is twice as high as the output voltage of the first conversion stage, Vout, 1. FIG. 6 illustrates more precisely an example of an electrical circuit for the simulation of the conversion of the radiofrequency energy transported in two distinct frequency bands. The device for converting radiofrequency energy into direct current illustrated in FIG. 6 therefore comprises two conversion stages. For example, the first conversion stage 61 comprises a radio frequency filter 611 centered on the frequency 0.9 GHz, for recovering the energy emitted in the GSM900 band, a voltage shift module 612 comprising a first capacitor C1, and a first diode D1,1, and a voltage rectification module 613 comprising a second capacitor C2,1 and a second diode D2,1. The second conversion stage 62 comprises a radiofrequency filter 621 centered on the 2.1 GHz frequency, making it possible to recover the energy emitted in the UMTS2100 band, a voltage offset module 622 comprising a first capacitor C1, 2 and a first diode. D1,2, and a voltage rectification module 623 comprising a second capacitor C2,2 and a second diode D2,2. The values of the diodes and capacitors can be chosen according to the load that one wishes to supply. For example, the diodes D1,1, D2,1, D2,1 and D2,2 have a threshold voltage of the order of 150 mV and the capacitors have a value of the order of 15 pF for the first capacitors C1 , 1 and C1,2 and 68 pF for the second capacitors C2,1 and C2,2. FIG. 7 illustrates the output voltage Vdc obtained at the output of the conversion device of FIG. 6, as a function of the incident power Pin, when: only the first conversion stage 61 is activated (ie when a radiofrequency signal is received only in the frequency band around the center frequency 0.9 GHz), curve 71; only the second conversion stage 62 is activated (i.e. when a radio frequency signal is received only in the frequency band around the 2.1 GHz center frequency), curve 72; the two conversion stages 61 and 62 are activated (ie when radiofrequency signals are received in the two frequency bands), curve 73. When the two stages receive an incident power greater than -30 dBm, the output voltage Vdc obtained in output of the conversion device is doubled with respect to the output voltage Vdc obtained when a single stage receives an incident power greater than - 30 dBm (ie when only one frequency band is activated).
    [0014] FIG. 8 illustrates the DC radio frequency conversion efficiency, as a percentage, of the conversion device of FIG. 6, as a function of the incident power Pin, when: only the first conversion stage 61 is activated (ie when radiofrequency signal is received only in the frequency band around the center frequency 0.9 GHz), curve 81; only the second conversion stage 62 is activated (i.e. when a radiofrequency signal is received only in the frequency band around the 2.1 GHz center frequency), curve 82; the two conversion stages 61 and 62 are activated (ie when radiofrequency signals are received in the two frequency bands), curve 83. It is again noted that when the two stages receive an incident power greater than -30 dBm, the is doubled with respect to the efficiency obtained when a single stage receives an incident power greater than -30 dBm (ie when only one frequency band is activated). These performance curves confirm that the voltages measured at 0.9 and 2.1 GHz respectively are correctly summed and do not interfere with each other, ie that the output of a conversion stage does not interfere with the output another conversion stage. For example, if the conversion device according to the invention is located 1 m from the radio frequency sources in operation, the recovered power is of the order of 15 ilw. Now it is possible to calculate the incident power at the input of the rectifier as a function of the Friis relation. We obtain a total incident power of the order of 50uW. Thus the efficiency of the conversion device according to the invention is of the order of 30%, whereas for a single frequency band it is of the order of 15%. There is therefore a gain on the output with a conversion device implementing several conversion stages. The conversion device according to the invention therefore has improved performance compared to the techniques of the prior art, in terms of DC output voltage, RF-DC conversion efficiency or the minimum power required to start the circuit. In addition, the DC contributions of each frequency band / conversion stage are not disturbed with respect to each other. In particular, compared to the Greinacher type rectifiers according to the prior art, the activation of the circuit according to the invention requires a minimum power of the order of -30 dBm, whereas the rectifiers according to the prior art require a minimum power of 1%. order -10 dBm. Thus, at equivalent power, the conversion efficiency of the circuit according to the invention is six times higher than that of the systems of the prior art. In addition, the circuit according to the invention is based on the use of two times fewer components than existing architectures, which implies lower production costs. The current generated 1m at the output of the conversion device, or equivalently the voltage Vdc generated at the output of the conversion device, can be used to feed a load, for example a temperature sensor. One of the advantages of the invention therefore lies in the fact that it can directly supply electronic devices with the surrounding energy, and can in particular be used to recharge a battery / battery of such an electronic device. FIG. 9 illustrates an exemplary application of the invention for feeding a sensor, for example a thermometer. As illustrated in this figure, such a sensor comprises data collection means 91, data recovery means 92 collected and a conversion device 93 of radiofrequency energy DC as described above.
    [0015] In particular, as already indicated, the invention finds particular applications in the field of wired or wireless sensor power supply, for example in the field of textile, medical, weather, sports, radio frequency identification , telephony, surveillance, etc.
    权利要求:
    Claims (10)
    [0001]
    REVENDICATIONS1. Device for converting radiofrequency energy into direct current, receiving as input at least one radiofrequency signal and generating as output a direct current capable of supplying at least one load, characterized in that said conversion device comprises at least one conversion stage ( 41) comprising: a radio frequency filtering module (411), connected to a first input node (E1) of said conversion stage, configured to filter one of said at least one radio frequency signal; a voltage shift module (412), connected between a second input node (E2) of said conversion stage, said radio frequency filtering module (411) and an intermediate node (A) of said conversion stage, configured to move a voltage present at said first (E1) input node on said intermediate node (A); a voltage rectification module (413) connected between said intermediate node (A), said second input node (E2) and an output node (B) of said conversion stage configured to rectify the voltage of said intermediate node ( A) and delivering a rectified voltage to said output node (B); said second input node (E2) being connected to either a reference voltage or the output node of another conversion stage, and said direct current being generated on said output node (B) if said output node (B) is not connected to a second input node of another conversion stage.
    [0002]
    2. Conversion device according to claim 1, characterized in that said voltage shift module (412) implements a first capacitor (C1, i) connected between said filter module and said intermediate node, and a first diode (D1, i), connected in a forward direction between said second input node and said intermediate node, and in that said voltage rectification module (413) implements a second capacitor (C2, i), connected between said second input node and said output node, and a second diode (D2, i), connected in a forward direction between said intermediate node and said output node.
    [0003]
    Conversion device according to claim 2, characterized in that said first and second diodes and said first and second capacitors are surface mounted components.
    [0004]
    4. Conversion device according to any one of claims 2 and 3, characterized in that said first and second diodes have substantially identical values.
    [0005]
    5. Conversion device according to any one of claims 2 to 4, characterized in that said first and second diodes are Schottky diodes.
    [0006]
    6. Conversion device according to any one of claims 1 to 5, characterized in that it comprises at least one antenna for receiving said at least one radiofrequency signal.
    [0007]
    7. Conversion device according to claim 6, characterized in that said receiving antenna is a broadband antenna.
    [0008]
    8. Conversion device according to any one of claims 1 to 7, characterized in that said radiofrequency filtering module comprises a radio frequency filter belonging to the group comprising: a bandpass filter centered on the frequency 900MHz; a bandpass filter centered on the 1800MHz frequency; a bandpass filter centered on the 2.1 GHz frequency; a bandpass filter centered on the 2.4GHz frequency.
    [0009]
    9. Conversion device according to any one of claims 1 to 8, characterized in that said at least one radiofrequency signal is received via a wire link.
    [0010]
    10. A sensor comprising data collection means (91) and data recovery means (92), characterized in that it also comprises a conversion device (93) of radiofrequency energy to direct current, receiving in inputting at least one radiofrequency signal and outputting a direct current supplying said sensor, said converting device comprising at least one conversion stage comprising: a radio frequency filtering module (411), connected to a first input node of said stage of conversion configured to filter one of said at least one radio frequency signal; a voltage shift module (412), connected between a second input node of said conversion stage, said radio frequency filtering module and an intermediate node of said conversion stage, configured to move a voltage present at said first node of said conversion stage; input to said intermediate node; a voltage rectification module (413), connected between said intermediate node, said second input node, and an output node of said conversion stage, configured to rectify the voltage of said intermediate node and output a rectified voltage to said output node ; said second input node being connected to either a reference voltage or to the output node of another conversion stage, and said direct current being generated on said output node if said output node is not connected to a second input node of another conversion stage.
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    同族专利:
    公开号 | 公开日
    WO2015121388A1|2015-08-20|
    ES2707753T3|2019-04-04|
    US20160359378A1|2016-12-08|
    FR3017752B1|2017-10-13|
    EP3108569B1|2018-10-24|
    EP3108569A1|2016-12-28|
    CA2938483A1|2015-08-20|
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    US9935370B2|2014-12-23|2018-04-03|Palo Alto Research Center Incorporated|Multiband radio frequencyenergy harvesting with scalable antenna|
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    CN107800203A|2017-12-11|2018-03-13|中山大学|Energy receiver|
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    法律状态:
    2016-02-23| PLFP| Fee payment|Year of fee payment: 3 |
    2017-02-24| PLFP| Fee payment|Year of fee payment: 4 |
    2018-02-23| PLFP| Fee payment|Year of fee payment: 5 |
    2019-02-28| PLFP| Fee payment|Year of fee payment: 6 |
    2020-02-18| PLFP| Fee payment|Year of fee payment: 7 |
    2021-02-17| PLFP| Fee payment|Year of fee payment: 8 |
    2022-01-19| PLFP| Fee payment|Year of fee payment: 9 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1451192A|FR3017752B1|2014-02-14|2014-02-14|CONTINUOUS RADIO FREQUENCY ENERGY CONVERSION DEVICE AND CORRESPONDING SENSOR|FR1451192A| FR3017752B1|2014-02-14|2014-02-14|CONTINUOUS RADIO FREQUENCY ENERGY CONVERSION DEVICE AND CORRESPONDING SENSOR|
    US15/119,043| US20160359378A1|2014-02-14|2015-02-12|Device for converting radiofrequency energy into dc currentand corresponding sensor|
    ES15705572T| ES2707753T3|2014-02-14|2015-02-12|Device for converting radiofrequency energy into a direct currentand corresponding sensor|
    CA2938483A| CA2938483A1|2014-02-14|2015-02-12|Device for converting radiofrequency energy into dc currentand corresponding sensor|
    EP15705572.4A| EP3108569B1|2014-02-14|2015-02-12|Radiofrequency to dc energy conversion deviceand receiver therefor|
    PCT/EP2015/053031| WO2015121388A1|2014-02-14|2015-02-12|Device for converting radiofrequency energy into dc currentand corresponding sensor|
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