Radio frequency control system for a household appliance, including a printed circuit board coupler

Abstract

The invention relates to a radio frequency signal control system for a household appliance (2) controlled by a management unit (3), the system comprising: - a radio frequency signal coupler (10), comprising a line segment (13a) printed on a printed circuit board (9) having a free end (13b) and connected in parallel with a transmission line (13) printed on the printed circuit board (9) the first end of which is connected to an electrical conductor (5), the coupler (10) comprising at least one coupling line (15a) a portion of which extends without electrical contact, parallel to the line segment (13a);- a radio frequency unit (7) for transmitting and / or receiving radio frequency signals comprising a radio frequency signal input and / or output (Sa) electrically connected to the coupler, - a radio frequency signal blocking circuit (12), printed on the printed circuit board and connected at one end to the transmission line (13).;

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency signal control of a domestic electrical appliance supplied with electrical energy by an electrical power supply network.

[0002] The present invention finds particularly advantageous applications in the field of controlling electromechanical actuators used in a closing or solar protection installation using screens, blinds or shutters for example. Previous technique

[0003] In the state of the art, electromechanical actuators used in a closing or protection installation are known to be equipped with a radio frequency receiver and transmitter fitted with a receiving and transmitting antenna, allowing the sensitivity to be increased and therefore the transmission range between a radio frequency transmitter, mobile or fixed, and the radio frequency receiver.

[0004] The receiving and transmitting antenna is a sensitive and fragile component. Furthermore, the actuator is often housed in a metal casing, which necessitates placing the antenna outside the casing to preserve the sensitivity of the radio frequency receiver.

[0005] Numerous technical solutions have been proposed to use the actuator's power supply cable to house part of the antenna, or to use a phase conductor and / or a neutral conductor as an antenna, either by direct coupling or by partial coupling.

[0006] For example, patent EP 2 109 226 describes a radio frequency control device for a household electrical appliance supplied with power from an electrical power supply. The radio frequency control device includes a radio frequency unit for transmitting and / or receiving radio frequency signals. The radio frequency control device includes a first electrical conductor and a second electrical conductor for supplying power.

[0007] The radio frequency signal control device includes an antenna electrically connected to the radio frequency unit. At least one of the two electrical conductors of the power supply network serves as a receiving or transmitting antenna for the radio frequency signals. The radio frequency unit includes a radio frequency signal output and / or input electrically connected to a coupler connection point.

[0008] The radio frequency signal control device comprises a printed circuit board on which turns forming a coil are printed to create the coupler. The electrical connection between the radio frequency signal output and / or input of the radio frequency unit and the coupler connection point allows the radio frequency signal output and / or input of the radio frequency unit to be electrically connected to an additional terminal of the coil located between the two end terminals of the coil.

[0009] The coupler is connected, at one end, to the first electrical conductor of the radio frequency signal control device and, at the other end, to a reference voltage of the radio frequency unit. The current from the mains power supply, which powers the household electrical appliance, flows through the coupler between its first and second ends.

[0010] However, this radio frequency signal control device has the drawback of implementing the coupler using a coil made of printed turns on the device's circuit board. In cases where a high current powers the household appliance, such a printed coil occupies a significant amount of space on the circuit board due to the width of the traces on the board that house the coil and the electrical conductor connected to it.

[0011] Indeed, the sizing of these printed circuit board traces is linked to the value of the supply current of the household electrical appliance flowing through the coupler, which consists of the coil formed by printed turns. Consequently, the space occupied by the coil on the printed circuit board increases the cost of obtaining the printed circuit board for the radio frequency signal control device and requires a large space within the household electrical appliance for the assembly of the printed circuit board.

[0012] Therefore, manufacturing the printed circuit board with such a winding formed by printed turns is complex to industrialize, creates difficulties in guaranteeing the reliability of the radio frequency signal control device during mass production, and increases the cost of obtaining the printed circuit board for the radio frequency signal control device.

[0013] To address these drawbacks, patent EP 3,221,970 proposes a radio frequency control device for a household electrical appliance. This device allows for the integration of a coupler onto a printed circuit board of the control device, while eliminating the problems associated with the current of the power supply flowing through the coupler and / or the operating frequency of the radio frequency unit. According to this patent, the coupler consists of a transmission line printed on the printed circuit board. One end of the printed transmission line is electrically connected to the first electrical conductor of the control device, while the other end is electrically connected to a first reference voltage.Furthermore, the connection point of the coupler, formed by the printed transmission line, is located between the first and second ends of the printed transmission line. In addition, the control device includes an antenna electrically connected to the radio frequency unit via one of the electrical conductors of the power supply network. The first electrical conductor of the control device is connected to the power supply network, and the coupler matches the output and / or input impedance of the radio frequency unit to the impedance of the antenna.

[0014] One drawback of the control device described in this patent is the need to mount the coupler parallel to the transmission line. This constraint limits the possible configurations of the printed circuit board. Furthermore, the coupler is connected to a reference voltage that does not provide electrical isolation between the power supply and the radio frequency unit. It should be noted that the operation of the control device described in this patent is sensitive to the load and impedance of the electromechanical actuator.

[0015] Document FR 2 944 385 describes a radio frequency control system for a domestic electrical appliance controlled by a management unit and supplied with electrical energy via a first electrical conductor CE1 and a second electrical conductor of a power supply network. This system includes a radio frequency signal coupler comprising a transmission line printed on a printed circuit board and having one end connected to the first electrical conductor and a second end connected to the management unit. The coupler includes, as an antenna, a structure of etched tracks that form a coil around an electrical conductor coupled at its ends to a reference plane in zones P1 and P2. This system includes a radio frequency unit for transmitting and / or receiving radio frequency signals comprising a radio frequency signal input and / or output electrically connected to the antenna.One drawback of this control device concerns the implementation of the antenna in the form of tracks etched around the transmission line. Developing this coupling device is not easy and requires consideration of at least five physical parameters for its design: the distance between the antenna and the CE1 line, the length of the coupling zone, the line widths within the coupling zone, the load impedance in zone P1, and the load impedance in zone P2. Consequently, the device appears quite difficult to develop and hard to transfer from one device to another. Furthermore, the design of the load impedances is not described and seems complex to implement, likely with a significant risk of variability in the device's characteristics and performance.

[0016] Document FR 2 944 385 A1 describes a radio frequency signal transmission / reception device for household appliances powered by an electrical network, enabling the control and transmission of information. Description of the invention

[0017] The present invention aims to remedy the drawbacks of the prior art by proposing a radio frequency signal control system for a domestic electrical appliance, allowing the radio frequency signal coupler to be completely embedded on a printed circuit board without requiring electronic components.

[0018] Another object of the invention is to provide a radio frequency signal control system for a household electrical appliance, designed to optimize the flow of radio frequency signals between the antenna and the radio frequency unit.

[0019] Another object of the invention is to provide a control system whose behavior is insensitive to variations in the impedance of the household electrical appliance.

[0020] To achieve these objectives, the control system according to the invention comprises: a printed circuit board; a radio frequency signal coupler, comprising at least one transmission line printed on the printed circuit board in an extension direction and having a first end connected to the first electrical conductor and a second end connected to the control unit, the coupler comprising at least one coupling line printed on the printed circuit board; a radio frequency unit for transmitting and / or receiving radio frequency signals comprising a radio frequency signal input and / or output electrically connected to a connection point of the coupling line of the coupler, characterized in that: The coupler comprises a line segment printed on the printed circuit board, having one free end and being connected in parallel to the transmission line at a connection point, the coupling line comprising a coupling portion extending without electrical contact, parallel to the line segment; and in that a radio frequency signal blocking circuit is printed on the printed circuit board and connected by one end to the transmission line at a connection point between the connection point of the coupler line segment and the management unit.

[0021] According to one feature of the invention, the coupling line of the coupler is configured to form a quarter wave line.

[0022] According to one embodiment, the coupling line has two printed coupling parts to present a U-shaped configuration surrounding, without electrical contact, the line segment.

[0023] According to another embodiment, the coupler coupling line is printed to present a straight configuration or in the shape of an L.

[0024] According to another embodiment, the line segment is printed on the printed circuit board in a direction not parallel to the extension direction of the transmission line.

[0025] Advantageously, the directions of the line segment and the transmission line form an angle between 30° and 150°.

[0026] According to a preferred implementation example, the coupler is configured to ensure attenuation of less than 3dB between the coupler's connection point and the first end of the transmission line connected to the first electrical conductor.

[0027] According to one feature of the invention, the blocking circuit comprises a portion of a line printed on the printed circuit board having a free end.

[0028] According to another feature of the invention, the portion of the line of the blocking circuit has an electrical length adapted so that, depending on the length of the transmission line between the connection point of the coupler and the connection point of the blocking circuit, the radio frequency signals are blocked at the connection point of the coupler, with an attenuation greater than 10db.

[0029] Advantageously, the blocking circuit has an electrical length between the coupler connection point and the free end of the line portion equal to Lambda / 2, where Lambda is the wavelength.

[0030] Another object of the invention is to provide a domestic electrical appliance comprising a radio frequency signal control system in accordance with the invention. Brief description of the drawings

[0031] [ Fig. 1 ] There figure 1 is a simplified electrical diagram of a system according to the invention, for controlling a household electrical appliance by radio frequency signals. Fig. 2 ] There figure 2 represents an example of the implementation of an electrical diagram laid out on a printed circuit board, used in the radio frequency signal control system of a household electrical appliance. Fig. 3 ] There figure 3 is a diagram of another example of an embodiment of a coupler implemented in the control system according to the invention. Fig. 4 ] There figure 4 is a diagram of another example of an embodiment of a coupler implemented in the control system according to the invention. Fig. 5 ] There figure 5 is a diagram of another example of an embodiment of a coupler implemented in the control system according to the invention. Description of embodiments

[0032] As shown in the figures, the object of the invention relates to a radio frequency signal control system 1 for a household electrical appliance 2 controlled by a control unit 3. The household electrical appliance 2 and the control unit 3 are supplied with electrical energy by a power supply cable 4 comprising a first electrical conductor 5, for example, a neutral conductor, and a second electrical conductor 6, for example, a phase conductor. Furthermore, the power supply cable 4, which is supplied with electrical energy from the mains power supply, may include a protective electrical conductor. The protective electrical conductor of the power supply cable 4 is connected to earth and to a metallic structure of the household electrical appliance 2.

[0033] According to an advantageous application, the domestic electrical appliance 2 includes an electromechanical actuator for a home automation system for closing or sun protection. As described, for example, in patent application EP 3 221 970, the electromechanical actuator comprises an electric motor 2a housed in a winding tube of a screen such as a roller shutter or blind. It should be noted that the control system 1 according to the invention is suitable for operating, as a domestic electrical appliance 2, for example, a ventilation or alarm device, or a weather parameter detection system installed in a building or its external environment.

[0034] The control system 1 includes a radio frequency unit 7 for transmitting and / or receiving radio frequency signals to control the household electrical appliance 2. This radio frequency unit 7 is powered by an energy converter of any type known per se, not shown and connected to the electrical supply network 4. This radio frequency unit 7 includes an output and / or an input Sa of radio frequency signals from a localized or centralized control device 8 such as a remote control or other radio frequency device.

[0035] The radio frequency signals emitted by the control unit 8 contain commands to operate the household electrical appliance, and more specifically, in the illustrated example, the electric motor 2a. The commands received by the radio frequency unit 7 are transmitted to the control unit 3 of the electric motor 2a, so as to initiate rotation in a first or second direction, or to stop the rotation. In an advantageous embodiment, the radio frequency unit 7 also allows the transmission of radio frequency signals to the control unit 8 via its input / output Sa, including information relating to the operation of the electric motor 2a.

[0036] The control system 1 includes a printed circuit board 9 on which are mounted the components of the management unit 3 and the radio frequency unit 7. The first electrical conductor 5 and the second electrical conductor 6 are also partially arranged on the printed circuit board 9.

[0037] According to the invention, the input / output Sa of the radio frequency unit 7 is electrically connected to a connection point Pl of a coupler 10 for the radio frequency signals carried by an electrical conductor of the power supply cable 4, namely the first electrical conductor 5 in the illustrated example. According to the invention, the coupler 10 is mounted on the printed circuit board 9, on which is also mounted a blocking circuit 12 for the radio frequency signals, directed towards the household electrical appliance 2, as will be explained in detail later in the description.

[0038] As is evident from figures 1 et 2 The radio frequency signal coupler 10 comprises at least one transmission line 13 printed on the printed circuit board 9 along a straight extension direction XX in the illustrated example. One end of this transmission line 13 is connected to the first electrical conductor 5 at a point A, while the second end of this transmission line 13 is connected to the control unit 3 of the electric motor 2a, at a point B of the first electrical conductor 5 supplying the control unit 3.

[0039] The coupler 10 includes a line segment 13a printed on the printed circuit board 9 and connected in parallel to the transmission line 13 at a connection point Pc. This line segment 13a has, opposite its end connected to the transmission line 13, a free end 13b in an open circuit. According to an advantageous embodiment, the line segment 13a is printed on the printed circuit board 9 in a direction not parallel to the extension direction XX of the transmission line 13. Advantageously, the directions of the line segment 13a and the transmission line 13 form an angle β between 30° and 150°. In the example illustrated in the figure 2 The line segment 13a is printed on the printed circuit board 9, advantageously in a direction perpendicular to the extension direction XX of the transmission line 13 (β = 90°). In the embodiment illustrated in the figure 5 , the line segment 13a is printed on the printed circuit board 9, in a direction forming an angle β= 45° with respect to the transmission line 13.

[0040] Similarly, it should be noted that in the figures, the line segment 13a is printed on the printed circuit board 9 with a straight line. Of course, the line segment 13a can be printed on the printed circuit board 9 with one or more curves.

[0041] The coupler 10 includes a coupling line 15 printed on the printed circuit board 9 and having at least one portion 15a extending without electrical contact, parallel to the line segment 13a. This coupling line 15 is printed on the printed circuit board 9 having at least one free end 15e in open circuit and, on the opposite side, an end connected to a connection point C with the input / output Sa of the radio frequency unit 7.

[0042] Advantageously, the coupling line 15 of the coupler is configured to form a quarter-wave line. Conventionally, the coupling line 15 is formed by a conductor printed on the printed circuit board with an electrical length that is approximately equal to one-quarter of the wavelength of the radio frequency signals used to control the household electrical appliance. Regardless of the frequency, the electrical length of the coupling line 15 is approximately one-quarter of the wavelength of that frequency.

[0043] This coupling line 15 can have different configurations. According to an advantageous variant illustrated in the figure 2 The coupler's coupling line 15 is printed to present a U-shaped configuration surrounding, without electrical contact, the line segment 13a. In this example, the coupling line 15 comprises two coupling sections 15a extending on either side of the line segment 13a and parallel to each other and to the line segment 13a. These two coupling sections 15a have open-circuited free ends 15e located near the transmission line 13 and opposite ends connected by a link segment 15b connected to the connection point C. This U-shaped coupling minimizes coupling losses. This solution also results in a compact form.

[0044] In the illustrated example, the coupling sections 15a are straight because the line segment 13a is straight. Of course, as explained above, the line segment 13a can be printed on the printed circuit board 9 in a non-straight direction. In this case, the coupling sections 15a of the coupling line 15 are printed on the printed circuit board 9 extending, without electrical contact, in a non-straight direction, parallel to the line segment 13a.

[0045] There figure 3 This illustrates another embodiment in which the coupling line 15 of the coupler 10 is printed to present a straight configuration. According to this example, the coupling line 15 of the coupler has a coupling portion 15a extending without electrical contact, parallel to the line segment 13a, substantially along the entire length of the line segment 13a. This coupling portion 15a has a free end 15e in an open circuit, located near the transmission line 13, and an opposite end connected to the connection point C. It should be noted that in the embodiment illustrated in the figure 5 , the coupling line 15 of the coupler 10 is printed to present a straight configuration parallel to the line segment 13a extending in a direction forming an angle β= 45° with respect to the transmission line 13. The coupling line 15 of the coupler 10 is printed parallel to the line segment 13a on one or the other of its sides.

[0046] There figure 4 This illustrates another embodiment in which the coupler coupling line 15 is printed to present an L-shaped configuration. According to this example, the coupler coupling line 15 comprises a first coupling section 15a extending without electrical contact, parallel to the line segment 13a, substantially along the entire length of the line segment 13a, extending at a right angle beyond the free end 13b of the line segment 13a with a second coupling section 15b. This first coupling section 15a has an open-circuit free end 15e located near the transmission line 13, while the second coupling section 15b is connected to the connection point C.

[0047] Regardless of the embodiment of the coupler 10, it should be noted that there is no electrical contact between the first electrical conductor 5 and the antenna line of the radio frequency unit 7 (the input / output Sa of the radio frequency unit 7). Electrical isolation between the power line and the radio frequency line is achieved through the natural galvanic isolation provided by the printed circuit board 9. The width of the coupler lines 10 (namely the coupling sections 15a and the line segment 13a) and the spacing between the coupler lines are adjusted to allow impedance matching between the connection point Pc and the connection point C in order to maximize radio frequency energy transfer.

[0048] According to an advantageous feature, the coupler 10 is configured to obtain an attenuation of less than 3dB between the coupler connection point Pc and the first end of the transmission line 13 connected to the first electrical conductor 5.

[0049] According to another feature of the invention, the control system 1 includes a radio frequency signal blocking circuit 12 for rejecting radio frequency signals to the motor 2a. This blocking circuit 12 is printed on the printed circuit board 9 and is connected at one end to the transmission line 13 at a connection point Pr located between the connection point Pc of the line segment 13a of the coupler and the control unit 3. The blocking circuit 12 thus includes a portion of line 12a printed on the printed circuit board 9 with a free end 12b in an open circuit, such that this portion of line 12a can be considered as electrically connected in parallel to the transmission line 13. This portion of line 12a is connected to the transmission line 13 at the connection point Pr.

[0050] In the examples of implementation illustrated in figures 2 à 4 The portion of line 12a and the section of line 13a of the coupler are printed on the printed circuit board 9, on the same side of the transmission line 13. In the embodiment illustrated in the figure 5 , the portion of line 12a and the section of line 13a of the coupler are printed on the printed circuit board 9, on either side of the transmission line 13.

[0051] This radio frequency signal blocking circuit 12, designed to direct radio frequency signals towards the power line and not towards motor 2a, is achieved via an open-circuit stub. The property of this stub is to create a virtual short circuit for the radio frequency signals on the line from the first electrical conductor 5 to motor 2a, but also a virtual high-impedance open circuit at the connection point Pc, at the desired frequency. The geometry of this blocking circuit can be implemented in various ways, depending in particular on the space constraints available on the printed circuit board 9.

[0052] The portion of line 12a of the blocking circuit 12 has an electrical length adapted so that, depending on the length of the transmission line 13 between the coupler connection point Pc and the blocking circuit connection point Pr, the radio frequency signals are blocked at the coupler connection point Pc, with an attenuation greater than 10 dB. Ideally, the attenuation is greater than 20 dB. Thus, the line of the first electrical conductor 5 presents a high impedance at the connection point Pc, preventing the radio frequency signals from reaching the motor 2a.

[0053] The blocking circuit 12 has an electrical length between the coupler's connection point Pc and the free end 12b of the line segment 12a equal to λ / 2 (λ being the wavelength), corresponding to an electrical length of approximately 180°. The width of the transmission line 13 is adjusted to allow lossless transmission of the continuous signal and to maintain an impedance close to 50 ohms. The radio frequency signals are naturally routed to the line of the first electrical conductor 5.The blocking circuit 12 advantageously forces radio frequency signals to flow from point A of the transmission line 13 to the connection point C and vice versa with a loss of less than 3 dB, while prohibiting the passage of these radio frequency signals from the connection point C to point B of the transmission line but also from point A of the transmission line 13 to point B of the transmission line, with an isolation of at least 10dB.

[0054] One advantage of the invention is that the coupler is completely printable on a printed circuit board and requires no electronic components. All functions are performed by simple transmission lines. These transmission lines can be implemented in various ways, such as microstrip, stripline, or coplanar. Since the lines are fabricated on an epoxy dielectric substrate, specifically FR4 type, all line lengths and widths will depend on the physical and electrical characteristics of the substrate (e.g., permittivity, height, etc.). All line lengths are dependent on the operating frequency, which in the illustrated example is 2.4 GHz.

[0055] According to an example embodiment, if the operating frequency of the radio frequency unit 7 is 2.4 GHz, the air length of the coupler 10 is 30 mm and the air length of the stub, i.e., from the connection point Pc to the free end 12b, is 60 mm. It should be noted that the actual length on the printed circuit board 9 will be less than the air length, since the dielectric permittivity of the printed circuit board 9 must be taken into account.

[0056] Of course, the radio frequency signal control system can also operate in another radio frequency band, which can extend, in particular, between 400 MHz and 4 GHz, and can take, in particular, values ​​of the order of 433 MHz or 868 MHz.

Claims

1. A system for controlling with radiofrequency signals a home electric appliance (2) piloted by a management unit (3) and supplied with electrical energy by a first electrical conductor (5) and a second electrical conductor (6) of a power supply network, the system comprising: - a printed circuit board (9); - a coupler (10) of the radiofrequency signals, including at least one transmission line (13) printed on the printed circuit board along a direction of extension (X-X) and including a first end connected to the first electrical conductor (5) and a second end connected to the management unit, the coupler (10) including at least one coupling line (15) printed on the printed circuit board; - a radiofrequency unit (7) for emitting and / or receiving radiofrequency signals, comprising a radiofrequency signal input and / or output (Sa) electrically connected to a connection point (PI) of the coupling line of the coupler, the coupler (10) including a line segment (13a) printed on the printed circuit board by having a free end (13b) and by being joined in shunt to the transmission line (13), at a connection point (Pc), the coupling line (15) including a coupling part (15a) extending without electrical contact, parallel to the line segment (13a); - a circuit (12) for blocking the radiofrequency signals being printed on the printed circuit board and connected at one end on the transmission line (13) characterized in that: - the line segment (13a) has a free end (13b), - the blocking circuit (12) is connected on the transmission line (13) at a junction point (Pr) between the connection point (Pc) of the line segment (13a) of the coupler and the management unit (3).

2. The control system according to claim 1, wherein said at least one coupling line (15) of the coupler (10) is configured to form a quarterwave line.

3. The control system according to any of the preceding claims, wherein said at least one coupling line (15) includes two coupling parts (15a) printed to have a U-shaped configuration surrounding, without electrical contact, the line segment (13a).

4. The control system according any of claim 1 or 2, wherein said at least one coupling line (15) of the coupler is printed to have a rectilinear or L-shaped configuration.

5. The control system according to any of the preceding claims, wherein the line segment (13a) is printed on the printed circuit board (9) along a direction not parallel to the direction of extension (X-X) of the transmission line.

6. The control system according to the preceding claim wherein the directions of the line segment (13a) and of the transmission line (13) form together an angle β comprised between 30° and 150°.

7. The control system according to any of the preceding claims wherein the coupler (10) is configured so as to ensure an attenuation of less than 3 dB between the connection point (Pc) of the coupler and the first end of the transmission line (13) connected to the first electrical conductor.

8. The control system according to any of claims 1 to 7 wherein the blocking circuit (12) includes a line portion (12a) printed on the printed circuit board (9) by having a free end (12b).

9. The control system according to claim 8 wherein the line portion (12a) of the blocking circuit (12) has an electrical length adapted so that depending on the length of the transmission line (13) between the connection point (Pc) of the coupler and the junction point (Pr) of the blocking circuit (12), the radiofrequency signals are blocked at the connection point of the coupler (Pc), with an attenuation greater than 10 db.

10. The control system according to any of claims 8 or 9, wherein the blocking circuit (12) includes an electrical length between the connection point (Pc) of the coupler and the free end (12b) of the line portion (12a) equal to Lambda / 2, Lambda being the wavelength.

11. A home electric appliance characterized in that it comprises a radiofrequency signal control system (1) according to any of claims 1 to 10.

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