FR3008247A1 - METHOD AND DEVICE FOR CHARGING BY MAGNETIC COUPLING FOR A MOTOR VEHICLE - Google Patents

Abstract

The present invention relates to a device (10) for charging a mobile terminal by magnetic coupling, said charging device comprising a set of primary coils (11 0a-11 0d), an electrical source (100) adapted to form a signal of charging at a charging frequency, routing means (120) adapted to connect / disconnect each primary coil to the electrical source. The routing means are further adapted to connect / disconnect, when any one of the primary coils is connected to the electrical source, at least one other of said primary coils to a communication module (130) of the charging device adapted to form a communication signal at a communication frequency different from the charging frequency and incorporating communication data.

Description

The present invention relates to a device and a method for charging a mobile terminal by magnetic coupling. The present invention finds a particularly advantageous application, although in no way limiting, in onboard load devices in motor vehicles.

Magnetic coupling charging devices for wireless charging of mobile devices (mobile phones, laptops, tablets, digital cameras, etc.) are currently experiencing significant growth. Conventionally, a magnetic coupling charging device comprises a conductive coil, called "primary coil" which is connected to an electrical source. During charging of a mobile terminal, the electrical source forms a charging signal which makes it possible to circulate in the primary coil an electric current whose intensity varies with time. The primary coil thus fed forms a variable magnetic field. The mobile terminal comprises a conductive coil, called "secondary coil". When said secondary coil is placed in the variable magnetic field formed by the primary coil, an electric current is induced in said secondary coil. This electric current makes it possible to charge an electric accumulator connected to the secondary coil. Several types of magnetic coupling charging devices operating according to the general principle described above are known, in particular those defined by: the WPC consortium, which defines wireless power devices; so-called "magnetic induction" charge, - the consortium A4WP (which stands for "Alliance for 25 Wireless Power"), which defines charging devices known as "magnetic resonance". Magnetic induction charging devices, in particular, require precise positioning of the secondary coil relative to the primary coil, in order to have an effective load. For this purpose, it is known to equip the charging device with a plurality of primary coils distributed over a charging surface of said charging device, each primary coil being connectable to the electrical source. Whatever the position of the mobile terminal on the charging surface, it is then possible to select the primary coil for charging the mobile terminal in the most efficient manner possible. The positioning of the mobile terminal on the charging surface may therefore be less precise and less restrictive for the user of the mobile terminal.

It is desired nowadays to be able to exchange communication data with the mobile terminal simultaneously with a charge thereof by a magnetic coupling charging device. To exchange communication data with the mobile terminal simultaneously with a load thereof, different communication means may be used. Communication means of the Bluetooth®, WiFi®, etc. type, because they have a range of a few meters or more, may be remote from the charging device and therefore do not necessarily have to be integrated into said charging device.

Other means of communication, so-called "near field communication" (or NFC, acronym for the expression "Near Field Communication"), however, have a small range, less than a few centimeters, and must therefore be integrated into the device charge. There is therefore a need for magnetically coupled charging devices which incorporate communication means, in particular NFC, for exchanging communication data with a mobile terminal including during charging of said mobile terminal and without interfering with said mobile terminal. charge. It is an object of the present invention to provide a magnetic coupling charging device incorporating a communication module, preferably an NFC communication module, which can be both compact and inexpensive to manufacture. For this purpose, and according to a first aspect, the invention relates to a device for charging a mobile terminal by magnetic coupling, said charging device comprising a set of primary coils, an electrical source adapted to form a frequency load signal. the so-called "charging frequency", and routing means adapted to connect / disconnect each primary coil to the electrical source. The routing means are further adapted to connect / disconnect, when any one of the primary coils is connected to the electrical source, at least one other of said primary coils to a communication module of the charging device adapted to form a signal. main frequency communication, called "communication frequency", different from the charging frequency, said communication signal incorporating communication data to the mobile terminal. Such arrangements make it possible to limit the number of hardware resources to be integrated in the charging device in order to carry out both the charging of a mobile terminal and to exchange communication data with said mobile terminal.

Indeed, the charging device comprises a plurality of primary coils distributed over a load surface in order to release the positioning stress of the mobile terminal with respect to said load surface. Once selected the primary coil best placed to perform the load, called "charging coil", then there remains one or more primary coils, different from the charging coil and not used for charging, which can be used to exchange data. communication data with the mobile terminal. When the charging is complete, all the primary coils of the charging device can then be used to exchange communication data with the mobile terminal.

Therefore, thanks to the invention, it is not necessary to integrate in the charging device antennas dedicated to the exchange of communication data, because the primary coils not used for charging can be used to exchange data. communication data. The integration of the communication module in the charging device therefore requires the addition of a limited number of hardware means, so that the charging device can be compact and manufactured at a lower cost. In particular embodiments, the charging device may further comprise one or more of the following characteristics, taken individually or in any technically possible combination. In a particular embodiment, the charging device comprises a circuit for adapting the resonance frequency of each primary coil to the charging frequency, called the "load matching circuit", and a circuit for adapting the resonance frequency of each primary coil at the communication frequency, said "communication adaptation circuit", the routing means being further adapted to connect / disconnect each primary coil to the load matching circuit and the circuit of communication adaptation. Such arrangements make it possible to improve the efficiency of the load and the exchange of communication data. Indeed, a primary coil has its own resonance frequency which can be adjusted by means of a resonance frequency matching circuit mainly comprising a capacitor. Thus, by equipping the charging device with a load matching circuit and a communication matching circuit that can be connected to each primary coil, the resonance frequency of each primary coil can be adapted to the use which is made, chosen according to the location of the mobile terminal. In a particular embodiment, the routing means are further adapted to connect / disconnect, when any one of the primary coils is connected to the electrical source, at least one other of said primary coils to a control module of the electrical source for receiving load control data transmitted by a charging module of the mobile terminal. Such provisions improve the control of the load. Indeed, thanks to the invention, it is then possible to use a primary coil unused for charging the mobile terminal, that is to say not connected to the electrical source, to receive load control data issued by the charging module of the mobile terminal. Thus, the charging operations (by the transmission of the load signal) and the load control (by the reception of charge control data) are decoupled by the use of different primary coils.

In a particular embodiment, the charging device comprises a circuit for adapting the resonance frequency of each primary coil to the charging frequency dedicated to the reception of charge control data, called "control adaptation circuit". The routing means being further adapted to connect / disconnect each primary coil to the control adaptation circuit.

Such arrangements improve the decoupling between a primary coil used for the load and a primary coil used for load control. In a particular embodiment, the primary coils are arranged so that the mutual coupling between two adjacent primary coils is substantially zero.

In a particular embodiment, the charging device comprises means adapted to place primary coils in series. According to a second aspect, the invention relates to a motor vehicle comprising a charging device according to any one of the embodiments of the invention.

According to a third aspect, the invention relates to a method for charging a mobile terminal by magnetic coupling by means of a charging device according to any one of the embodiments of the invention, said charging method comprising steps of: - selection, according to the location of the mobile terminal, of a primary coil among the set of primary coils, called "charging coil", - connection of the charging coil to the electrical source, - terminal load movable by means of the charging coil, - connection of at least one primary coil different from the charging coil, called "communication coil", to the communication module of the charging device, - during charging of the mobile terminal : exchange of communication data with a communication module of the mobile terminal transmission by means of the communication coil. In particular embodiments, the charging method may further comprise one or more of the following features, taken alone or in any technically possible combination. In a particular mode of implementation, the charging method comprises connecting the communication coil to a circuit for adapting the resonance frequency of the communication coil to the communication frequency, called "adaptation circuit 10". Communication ". In a particular mode of implementation, the communication coil is an adjacent primary coil of the charging coil. In a particular mode of implementation, during charging of the mobile terminal, the communication coil is used both to transmit communication data to the communication module of the mobile terminal and to receive control data. charge unit issued by a charging module of said mobile terminal, said communication coil being, for the reception of said charge control data, disconnected from the communication module of the charging device and connected to a control module of the electrical source. In a particular mode of implementation, during the step of connecting the communication coil to the control module of the electrical source, said communication coil is connected to a circuit for adapting the resonance frequency of said communication coil at the charging frequency, dedicated to the reception of charge control data, called "control adaptation circuit". The invention will be better understood on reading the following description, given by way of non-limiting example, and with reference to the figures which represent: FIG. 1: a schematic representation of a preferred embodiment of a Magnetic coupling charging device, Figure 2: A diagram showing the main steps of a preferred embodiment of a magnetic coupling charging method, Figures 3, 4 and 5: Schematic representations of alternative embodiments Fig. 1. In these figures, like reference numerals from one figure to another designate identical or similar elements. For the sake of clarity, the elements shown are not to scale unless otherwise stated.

The present invention relates to a device 10 for charging a mobile terminal (not shown) by magnetic coupling. In the remainder of the description, reference is made in the case of a magnetic induction charging device, for example such as a WPC charging device. However, there is nothing to preclude, in other examples, considering other types of magnetic coupling load devices, including magnetic resonance (A4WP). FIG. 1 represents an exemplary embodiment of a magnetic induction charging device.

In general, the charging device 10 comprises an electric source 100 adapted to form a main frequency load signal called "charging frequency". The electrical source 100 is for example a current source adapted to form an alternating electric current at the charging frequency. In the case of a WPC charging device, the charging frequency is in principle between 100 and 200 kilohertz (kHz). The charging device 10 illustrated in FIG. 1 further comprises four primary coils 110a, 110b, 110c, 110d distributed over a charging surface of the charging device 10. Nothing, however, excludes, according to other exemplary embodiments, having a different number of primary coils, since the charging device comprises at least two primary coils. The primary coils 110a-110d are for example made in the form of tracks of a printed circuit. In a preferred embodiment, not illustrated by figures, said primary coils 110a-110d are arranged with a partial overlap between them, each primary coil 110a-110d having a partial overlap with at least one adjacent primary coil. For this purpose, the primary coils 110a-110d are for example arranged in at least two superposed planes of the printed circuit. In a preferred embodiment, the primary coils 110a-110d are arranged such that the mutual coupling between two adjacent primary coils is substantially zero. In other words, when a primary coil is energized and forms a magnetic field, the magnetic flux captured by the adjacent primary coils is substantially zero. The mobile terminal (for example a mobile phone, a laptop, a touch pad, a digital camera, etc.) comprises a charging module comprising in particular a secondary coil connected to an electric accumulator.

The charging device 10 also comprises a communication module 130 adapted to form a main frequency communication signal, called a "communication frequency", different from the charging frequency, the said communication signal incorporating communication data intended for communication purposes. a mobile terminal communication module. In a preferred embodiment, the communication module 130 of the charging device 10 and the communication module of the mobile terminal are NFC communication modules, the communication frequency then being of the order of 13.56 megahertz (MHz).

The charging device 10 also comprises a set of routing means 120 adapted to: - connect / disconnect each primary coil 110a-110d to the electrical source 100, that is to say that each primary coil 110a-110d can be used for charging the mobile terminal, and - when any one of the primary coils 110a-110d is connected to the electrical source 100, connecting / disconnecting at least one of said primary coils 110a-110d to the communication module 130, that is, that is, at least one primary coil can still be used to exchange communication data with the mobile terminal simultaneously with the charging of said mobile terminal. In the nonlimiting example illustrated in FIG. 1, the routing means 120 include, for this purpose, two selector circuits: a first primary coil selector circuit 121 adapted to connect the electrical source 100 to any one of the coils primary 110a-110d; a second primary coil selector circuit 122 adapted to connect the communication module 130 to any one of the primary coils 110a-110d.

In the preferred embodiment illustrated in FIG. 1, the charging device 10 further comprises a circuit for matching the resonant frequency of each primary coil 110a-110d to the charging frequency, referred to as the "voltage matching circuit". charge "150, and a circuit for matching the resonant frequency of each primary coil 110a-110d to the communication frequency, called the" communication matching circuit "160. By" adapting the resonant frequency to the frequency of charge "(respectively the communication frequency), it is meant that the resonance frequency of the assembly formed by the load matching circuit 150 (respectively the communication matching circuit 160) and a primary coil is equal or close of said charging frequency (respectively said communication frequency). By "close to the charging frequency" is meant that said resonance frequency is at a distance from said charging frequency which is less than 10% of the charging frequency. In the nonlimiting example illustrated in FIG. 1, the load matching circuit 150 and the communication matching circuit 160 each comprise a capacitor 151, 161 of suitable value adapted to adapt the resonance frequency of a coil. primary 110a-110d at the charging frequency and the communication frequency respectively. Nothing excludes, according to other non-detailed examples, to have other components, including inductive components to change the inductance of the primary coil 110a-110d. In addition, the routing means 120 are adapted to connect / disconnect each primary coil 110a-110d to the load matching circuit 150 and to the communication matching circuit 160. In the nonlimiting example illustrated in FIG. for this purpose, said routing means 120 comprise: a first resonance frequency matching circuit 124, adapted to connect the load matching circuit 150 to any of the primary coils; second resonance frequency matching circuit switch circuit 125 adapted to connect the communication matching circuit 160 to any one of the primary coils. It should be noted that, depending on the respective values of the charging and communication frequencies, it is not necessarily necessary to have different resonance frequency matching circuits for charging and communication. Thus, in the example illustrated in FIG. 1, the capacitors 151 and 161 can have the same value if the charging frequency is close to the communication frequency. However, in the case of a charging device WPC (charging frequency of between 100 kHz and 200 kHz) comprising an NFC communication module (communication frequency of the order of 13.56 MHz), the adaptation circuits of FIG. resonant frequencies are preferably different for charging and communication, so as to obtain different respective resonant frequencies. In the exemplary embodiment illustrated in FIG. 1, the charging device 35 further comprises a power source control module 140 for receiving load control data transmitted by the charging module of the mobile terminal.

Such load control data comprise, for example, the level of charge of the electric accumulator of said mobile terminal, or any other information making it possible in particular to ensure that the mobile terminal is always present on the charging surface. In the case of a WPC loader, such load control data is provided and is transmitted substantially periodically by the mobile terminal, approximately every 200 milliseconds (ms). In the preferred embodiment illustrated in FIG. 1, the routing means 120 are further adapted to connect / disconnect, when any one of the primary coils 110a-110d is connected to the electrical source 100, at least one other of said primary coils to the control module 140 of the electrical source 100. Said routing means 120 comprise for this purpose a third primary coil selector circuit 123, adapted to connect the control module 140 of the electrical source 100 to any one of primary coils 110a-110d. Thus, it is possible to decouple the load and charge control operations by using a primary coil 110a-110d different from the load coil to receive load control data output from the load module of the mobile terminal. In order to improve the decoupling between charge and charge control operations, the charging device shown in FIG. 1 further comprises a circuit for matching the resonant frequency of each primary coil to the charging frequency. dedicated to the reception of charge control data, called "control adaptation circuit" 170. The control adaptation circuit 170 comprises for example a capacitor 171 of value adapted to adapt the resonance frequency of a primary coil 110a-110d at the charging frequency. In addition, the routing means 120 is adapted to connect / disconnect each primary coil 110a-110d to the control adaptation circuit. For example, the routing means 120 comprise a third resonance frequency matching circuit switch circuit 126 adapted to connect the control matching circuit 170 to any one of the primary coils 110a-110d. Load matching circuits 150 and control circuits 170 both adapt the resonance frequency of a primary coil 110a-110d to the load frequency. They can therefore be identical, that is, the capacitors 151 and 171 can have the same value. In a preferred embodiment, said load matching circuits 150 and control circuits 170 are preferably different in order to optimize the resonance frequency for the function performed. For example: the capacitor 151 of the load matching circuit 150 is of a value adapted to make the resonance frequency of a primary coil 110a-110d substantially equal to the charging frequency, in order to have an effective load and to limit the level of harmonics (for reasons of electromagnetic compatibility, particularly restrictive in motor vehicles), - the capacitor 171 of the control adaptation circuit 170 is of suitable value to make the resonant frequency of a primary coil 110- 110d close but different from the charging frequency, in order to limit the interference generated by the transmission of the charge signal by another primary coil of the charging device.

FIG. 2 shows the main steps of a method of charging a mobile terminal by means of a charging device as illustrated in FIG. 1. Said main steps are, after the mobile terminal has been detected and located on the charging surface of the charging device, the following: - 51 selection, depending on the location of the mobile terminal on the charging surface, of a primary coil among the set of primary coils 110a-110d, said "charging coil", - 52 connection of the charging coil to the electrical source 100 by means of the first primary coil selector circuit 121, - 53 charging of the mobile terminal by means of the charging coil, - 54 connection of at least one primary coil different from the charging coil and disconnected from the electrical source, called the "communication coil", to the communication module 130, by means of the second primary coil selector circuit 122, - during charging of the mobile terminal: 55 exchange of communication data with a communication module of the mobile terminal transmission by means of the communication coil. For example, if the mobile terminal is placed on the charging surface at the primary coil 110b, then said primary coil 110b is preferably used as a charging coil, and connected to the power source 100 by means of the first selector circuit 121 primary coil. In a preferred embodiment, the communication coil is an adjacent primary coil 110a-110d of the charging coil. Such arrangements are advantageous in that the mobile terminal, such as a mobile phone, will generally be small in size, so that the secondary coil and an antenna of the communication module of the mobile terminal will generally be close. Therefore, considering, for the communication coil, a primary coil 110a-110d close to the charging coil, the data exchange with the mobile terminal will be more efficient. If the charging coil is the primary coil 110b, then the communication coil is preferably the primary coil 110a or the primary coil 110c.

In the remainder of the description, non-limiting is placed in the case where the primary coil 110b is used as a charge coil, and the primary coil 110a is used as a communication coil. In the context of the implementation of the charging device 10 of FIG. 1, the charging method 50 also advantageously comprises: during the step 52 of connecting the charging coil 110 a to the electrical source 100: connecting said charge coil to the load matching circuit 150 by means of the first resonance frequency matching circuit selector circuit 124, during the step 54 of connecting the communication coil 110a to the module 130 communication: the connection of said communication coil to the communication matching circuit 160 by means of the second resonance frequency matching circuit switch circuit 125. In addition, in order to control the load of the mobile terminal, the charging method 50 may include a step 56 of connecting a primary coil 110a-110d different from the charging coil to the control module 140 of the electrical source 100, for receive load control data transmitted by the mobile terminal. In the context of the implementation of the charging device 10 of FIG. 1, the step 56 of connecting a primary coil 110a-110d to the control module 140 comprises the connection of said primary coil to the adaptation circuit of FIG. control 170 by means of the third selector circuit 126 of resonance frequency matching circuit. Preferably, the communication coil 110a is used both for transmitting communication data and for receiving load control data during distinct respective time slots. In the case of a WPC charging device, the communication coil 110a is for example used by default to transmit communication data and, every 200 ms, said communication coil 110a is used to receive load control data. . Thus, during the step 56 of connecting the communication coil to the control module 140, said communication coil is also disconnected from the communication module 130. The steps 54 of connection of the communication coil 110a to the communication module 130 and 56 of connection of said communication coil to the control module 140 are therefore iterated over time, during the entire duration of the charging step 53. More generally, it should be noted that the modes of implementation and realization considered above have been described by way of non-limiting examples, and that other variants are therefore possible, some of which are illustrated. 3 to 5. FIG. 3 shows an alternative embodiment of the charging device of FIG. 1, in which the third primary coil selector circuit 110a-110d has been replaced by a suitable module selector circuit 127. to connect the second primary coil selector circuit 122 to either the communication module 130 or to the control module 140 of the electrical source 100. This embodiment is particularly suitable for use of the communication coil both for transmitting communication data and to receive load control data during distinct time intervals. FIG. 4 shows an alternative embodiment of the charging device of FIG. 3, further comprising means adapted to place primary coils 110a-110d in series. More particularly, the charging device of FIG. 3 comprises two switches: a first switch 128a adapted to connect the output of the primary coil 110a to the input of the primary coil 110c; a second switch 128b adapted to connect the output of the primary coil 110d at the input of the primary coil 110b. The charging device 10 of FIG. 3 therefore makes it possible, in particular, to use a plurality of primary coils 110a-110d for transmitting communication data. For example, if the charging coil is the primary coil 110b, then the primary coil 110a can be connected to the communication module 130 and placed in series with the primary coil 110c, so that the two primary coils adjacent to the coil of Load 110b are used to transmit communication data. Similarly, if the charge coil is the primary coil 110c, then the primary coil 110d can be connected to the communication module 130 and placed in series with the primary coil 110b. More generally, the charging device 10 can be designed to connect a plurality of primary coils 110a-110d to the communication module 130, i.e. to use a plurality of communication coils to improve the communication. exchange of communication data. The communication coils can be put in series and / or in parallel.

FIG. 5 represents an alternative embodiment of the charging device of FIG. 3, in which: the load adaptation circuit is broken down into several associated load adaptation sub-circuits 150a, 150b, 150c and 150d. respectively to the primary coils 110a to 110d, the communication adaptation circuit is broken down into a plurality of communication matching sub-circuits 160a, 160b, 160c and 160d respectively associated with the primary coils 110a to 110d; The control adaptation is divided into several control adaptation sub-circuits 170a, 170b, 170c and 170d respectively associated with the primary coils 110a to 110d. In addition, primary coils 110a-110d have respective selector circuits 129a-129d for connecting each primary coil to either the associated load-matching subcircuit or the associated communication-matching subcircuit, or associated control adaptation subcircuit.

Claims (4)

CLAIMS1- Device (10) for charging a mobile terminal by magnetic coupling, said charging device comprising a set of primary coils (110a-110d), an electrical source (100) adapted to form a so-called main frequency charging signal "Charging frequency" means (120) for routing adapted to connect / disconnect each primary coil to the electrical source, characterized in that: - the routing means are further adapted to connect / disconnect, when any primary coils (110a-110d) are connected to the electrical source (100), at least one other of said primary coils to a communication module (130) of the charging device adapted to form a main frequency communication signal, called " communication frequency ", different from the charging frequency, the communication signal incorporating communication data, - the primary coils (110a-110d) are arranged so that the mutual coupling between two adjacent primary coils is substantially zero. 2 - Device (10) according to claim 1, characterized in that it comprises a matching circuit of the resonant frequency of each primary coil at the load frequency, said "load matching circuit" (150) and a circuit for matching the resonant frequency of each primary coil to the communication frequency, said "communication adaptation circuit" (160), the routing means (120) being further adapted to connect / disconnect each primary coil to the load matching circuit and the communication matching circuit. 3 - Device (10) according to any one of the preceding claims, characterized in that the means (120) for routing are further adapted to connect / disconnect, when any one of the primary coils (110a-110d) is connected at the power source (100), at least one other of said primary coils to a power source control module (100) (100) for receiving load control data output from a load module of the mobile terminal. 4 - Device (10) according to any one of the preceding claims, characterized in that it comprises a circuit for matching the resonant frequency of each primary coil at the load frequency, dedicated to the reception of control data load, said "control adaptation circuit" (170), the routing means being further adapted to connect / disconnect each primary coil to the control adaptation circuit. - Motor vehicle comprising a device (10) charge according to one of the preceding claims. 6 - Method (50) for charging a mobile terminal by magnetic coupling by means of a charging device (10) according to claim 1, characterized in that it comprises steps of: - (51) selection, according to the location of the mobile terminal, a primary coil among the set of primary coils (110a-110d), called "charging coil", - (52) connection of the charging coil to the electrical source, - (53) charging the mobile terminal by means of the charging coil, - (54) connecting at least one primary coil different from the charging coil, called the "communication coil", to the communication module (130) of the device (10) charging, during charging of the mobile terminal: (55) exchange of communication data with a communication module of the mobile terminal by means of the communication coil. 7 - Process (50) according to claim 6, characterized in that it comprises the connection of the communication coil to a circuit for matching the resonance frequency of said communication coil to the communication frequency, said "20 communication adaptation circuit "(160). 8 - Process (50) according to claim 6 or 7, characterized in that the communication coil is an adjacent primary coil (110a-110d) of the charging coil. 9 - Method (50) according to any one of claims 6 to 8, characterized in that, during the charging of the mobile terminal, the communication coil is used both to transmit communication data to the destination. communication module of the mobile terminal and for receiving load control data transmitted by a load module of said mobile terminal, said communication coil being, for the reception of said load control data, disconnected from the communication module (130) of the charging device and connected to a module (140) for controlling the electrical source. 10 - Method (50) according to claim 9, characterized in that, during the step (56) connection of the communication coil to the control module of the electrical source, said communication coil is connected to a circuit d adapting the resonant frequency of said communication coil to the charging frequency, dedicated to the reception of charge control data, called "control adaptation circuit".