US-12627180-B2 - Method for detecting an object to be charged and associated charging device

Abstract

A method for detecting an object to be charged by an induction-charging device including at least one transmitting coil. The method includes transmission, by the at least one coil, of an electrical pulse the value of which is within a window of values predetermined using test receivers, and the object to be charged generating a communication signal in response. The method including, if charging conditions are favorable, the modulation of the value of the electrical pulse outside of the window of predetermined values according to the presence and/or the value of the communication signal, in order to detect the presence of an object to be charged.

Inventors

• Brahim ALOUI
• JEAN-PHILIPPE SANCHIS
• Isabelle Bacaer

Assignees

• CONTINENTAL AUTOMOTIVE GMBH

Dates

Publication Date

20260512

Application Date

20220420

Priority Date

20210504

Claims (17)

1. 1 . A method for detecting an object to be charged by an induction-charging device comprising at least one transmitting coil, the method comprising: transmitting, by the at least one coil, an analog signal to detect whether charging conditions are favorable; transmitting, by the at least one coil, an electrical pulse the value of which is within a window of values predetermined using test receivers in a certification phase of the Wireless Power Consortium (WPC) standard to the object to be charged; and if charging conditions are favorable, in the absence of a communication signal modulating the value of the electrical pulse outside of the window of predetermined values of the WPC standard in order to detect the presence of the object to be charged, wherein the modulated electrical pulse has a voltage higher than an upper limit of the window of predetermined values of the WPC standard, and when a communication signal is received by the at least one coil at a maximum value, modulating the value of the electrical pulse outside of the window of predetermined values of the WPC standard in order to detect the presence of the object to be charged, wherein the modulated electrical pulse has a voltage lower than a lower limit of the window of predetermined values of the WPC standard.
2. 2 . The method for detecting an object to be charged by a charging device as claimed in claim 1 , comprising at least one transmitting coil, the method further comprising the following steps for each coil: a) detecting the presence of an object on a charging surface of said device; b) checking charging conditions; c) if the charging conditions are favorable: i) transmitting, to the object, an electrical pulse the value of which is within a window of values predetermined beforehand using test receivers in a certification phase; ii) if the object transmits a communication signal lower than a maximum value in response, then an object to be charged is detected, otherwise: iii) in the absence of a communication signal, or a communication signal of maximum value, then transmitting, to the object, a modified electrical pulse the value of which is located outside of the window of predetermined values: a. if the object transmits a communication signal in response, then an object to be charged is detected; b. otherwise a parasitic object is detected.
3. 3 . The detection method as claimed in claim 1 , wherein if the charging conditions are unfavorable, then the electrical pulse has a voltage lower than a lower limit predetermined beforehand using test receivers in a certification phase.
4. 4 . The detection method as claimed in claim 1 , wherein when the charging conditions are unfavorable for a coil, terminating transmission of the electrical pulse by the at least one coil.
5. 5 . The detection method as claimed in claim 1 , wherein, the charging device comprises a plurality of transmitting coils, the method is repeated for each coil.
6. 6 . The detection method as claimed in claim 5 , wherein when modulating the value of the electrical pulse based on the absence of a communication signal, modulating the value of the electrical pulse transmitted from each of the plurality of transmitting coils at a voltage higher than the upper limit of the window of predetermined values of the WPC standard, wherein the voltage for each transmitting coil is proportional to a different percentage value from the higher limit for each of the plurality of transmitting coils.
7. 7 . The detection method as claimed in claim 5 , wherein when modulating the value of the electrical pulse based on receiving a communication signal at a maximum value, modulating the value of the electrical pulse transmitted from each of the plurality of transmitting coils at a voltage lower than the lower limit of the window of predetermined values of the WPC standard, wherein the voltage for each transmitting coil is proportional to a different percentage value from the lower limit for each of the plurality of transmitting coils.
8. 8 . The detection method as claimed in claim 1 , further comprising a prior step of calibrating the voltage values of the modified electrical pulse outside of the window of predetermined values according to various types of objects to be charged.
9. 9 . The detection method as claimed in claim 1 , wherein the checking of favorable charging conditions comprises measuring at least one parameter of the at least one transmitting coil and comparing said measurement with predetermined threshold values of the same parameter, obtained beforehand for various types of objects to be charged.
10. 10 . The detection method as claimed in claim 9 , wherein the parameter is a quality factor, and/or a variation in resistance and/or a variation in inductance, and/or a variation in a resonant frequency of the transmitting coil.
11. 11 . A non-transitory computer program product comprising program code instructions for carrying out the steps of the detection method as claimed in claim 1 , when said program is executed on a computer.
12. 12 . A device for charging an object, comprising at least one transmitting coil, the device comprising: a) means for detecting an object on the charging surface; and, for each coil: b) means for checking charging conditions based on transmitting an analog signal to detect whether charging conditions are favorable; c) means for detecting the reception of a communication signal and for comparing the value of said received communication signal with a maximum value; and d) means for modulating a value of an electrical pulse transmitted by the at least one coil, outside of a window of values predetermined beforehand using test receivers in a certification phase of the of the Wireless Power Consortium (WPC) standard, according to the result of said check and according to the presence and/or the value of the communication signal, wherein in an absence of a communication signal, the value of the electrical pulse is modulated outside of the window of predetermined values of the WPC standard in order to detect the presence of the object to be charged, wherein the modulated electrical pulse has a voltage higher than an upper limit of the window of predetermined values of the WPC standard, and when a communication signal is received by the at least one coil at a maximum value, modulating the value of the electrical pulse outside of the window of predetermined values of the WPC standard in order to detect the presence of the object to be charged, wherein the modulated electrical pulse has a voltage lower than a lower limit of the window of predetermined values of the WPC standard.
13. 13 . The device for charging an object as claimed in claim 12 , wherein the checking means comprise means for measuring at least one parameter of the transmitting coil and means for comparing the measurement with predetermined threshold values of the same parameter, obtained beforehand for various types of objects to be charged.
14. 14 . The charging device as claimed in claim 13 , wherein the parameter is a quality factor, and/or a variation in resistance and/or a variation in inductance, and/or a variation in a resonant frequency of the transmitting coil.
15. 15 . A motor vehicle comprising a charging device as claimed in claim 12 .
16. 16 . The device for charging an object as claimed in claim 12 , wherein when modulating the value of the electrical pulse based on the absence of a communication signal, modulating the value of the electrical pulse transmitted from each coil at a voltage higher than the upper limit of the window of predetermined values of the WPC standard, wherein the voltage for each coil is proportional to a different percentage value from the higher limit for each of the coils.
17. 17 . The device for charging an object as claimed in claim 12 , wherein when modulating the value of the electrical pulse based on receiving a communication signal at a maximum value, modulating the value of the electrical pulse transmitted from each coil at a voltage lower than the lower limit of the window of predetermined values of the WPC standard, wherein the voltage for each coil is proportional to a different percentage value from the lower limit for each of the coils.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority to French Patent Application No. 2104667, filed May 4, 2021, the contents of such application being incorporated by reference herein. FIELD OF THE INVENTION The field of the invention is the field of magnetic induction charging devices. In particular, the invention relates to a method for detecting an object to be charged located close to a magnetic induction electrical charging device and to an associated charging device. BACKGROUND OF THE INVENTION Magnetic induction electrical charging technology is implemented in a system comprising a wireless electrical charging device and an electrical storage battery to be charged in a mobile terminal such as, for example, a portable item of user equipment, such as a mobile telephone. The electrical charging device comprises a transmission coil, or transmitting coil. The electrical storage battery comprises a receiving coil to be charged. When the transmission coil and the receiving coil are located opposite each other, variations in the magnetic field that is generated by the transmission coil cause an electric current to flow in the receiving coil, thereby charging the electrical storage battery. Induction charging technology meets the requirements of a standard, in this case it is the Qi® standard of the Wireless Power Consortium, also called the WPC standard. In order to detect the presence of an electrical storage battery comprising a receiving coil located opposite the transmission coil of the electrical charging device, three steps are currently implemented. In a first step, the methods of the prior art seek to detect the presence of an object located opposite the electrical charging device. For this purpose, electrical pulses, also called “analog pings” or “APs”, are sent at the charging frequency via the transmission coil of the electrical charging device to the receiving coil. An analog ping is a continuous signal, exhibiting periodic oscillations, with a period of, for example, 300 ms, and with an oscillation time of 5 to 20 ms. The voltage or the impedance at the terminals of the transmission coils is observed. If a variation in the voltage at the terminals of the transmission antenna or in the impedance of the transmission coil is detected, then there is an object opposite the transmission coil. In a second step, a “digital ping” or “DP” is sent by each transmitting coil of the charging device in order to make it possible to detect whether a compatible object to be charged is present on the charging surface of the device. The digital ping is also an electrical pulse, but it requests a response from the object to be charged. It makes it possible to identify whether the object placed on the charging surface is a compatible object to be charged, and which transmitting coil is best coupled with the receiving coil of the object to be charged. Specifically, the detected object may be either a parasitic object or a mobile apparatus such as a mobile telephone equipped with a receiving coil for induction electrical charging. In this second step, efforts are then made to establish digital communication with the detected object in order to identify its character. More particularly, it is sought to determine whether the detected object has a receiving coil for induction electrical charging in order to charge it. This communication is performed by modulating the amplitude of the voltage across the terminals of the transmitting coils in order to send an electrical pulse (digital ping). Next, the object to be charged, in the event of favorable coupling between one of the transmitting coils and the receiving coil, returns a communication signal called a “signal strength packet” or SSP signal to the charging device. The SSP communication signal is a value that the object returns to the charging device and which represents the coupling between its receiving coil and one of the transmitting coils of the charging device. The SSP communication signal corresponds to the ratio of the voltage of the rectifier, which converts the AC (alternating current) voltage of the receiving coil induced by receiving the digital ping into a DC voltage, to the maximum voltage of the rectifier allowed by the manufacturer of the object to be charged. If the charging device does not receive an SSP communication signal, it deems the object placed on the charging surface to be a parasitic object, i.e. one that is not compatible for charging, and induction charging is not initiated. Specifically, this occurs when the object to be charged is located in a region of the charging surface where coupling between the transmitting coil and the receiving coil is too weak. In order to trigger the transmission of an SSP communication signal, the digital ping DP sent by the charging device should observe levels for the voltages induced in the object to be charged that are set by the manufacturers and this should be for predetermined durat