CN-115284919-B - Method for detecting an object to be charged and associated charging device

Abstract

The invention proposes a method for detecting an object (T) to be charged by means of an inductive charging device (D) comprising at least one transmitting coil (B1, B2, B3), the method comprising transmitting an electrical pulse (DP) through said at least one coil (B1, B2, B3), the value of which electrical pulse (DP) is within a window (Vmin, vmax) of values predetermined using a test receiver, and the object (T) to be charged generating a communication signal (SSP) in response, the method comprising modulating the value of the electrical pulse (DP) outside the window (Vmin, vmax) of predetermined values in dependence on the presence and/or value of the communication signal (SSP) if charging conditions are favourable (Q, Δr, Δl, Δfres), in order to detect the presence of the object (T) to be charged.

Inventors

• B. Aloy
• J-P. Sanchez
• I. Bacar

Assignees

• 大陆汽车有限公司
• 大陆汽车有限公司

Dates

Publication Date

20260421

Application Date

20220429

Priority Date

20210504

Claims (15)

1. 1. A method for detecting an object (T) to be charged by means of an inductive charging device (D) comprising at least one transmitting coil (B1, B2, B3), the method comprising transmitting an electrical pulse (DP) through the at least one coil (B1, B2, B3), the value of the electrical pulse (DP) being within a window (Vmin, vmax) of values predetermined in an authentication phase using a test receiver, and the object (T) to be charged generating a communication signal (SSP) in response, the method being characterized in that if a charging condition (Q, Δr, Δl, Δfres) is favourable and in case of no communication signal (SSP) or a communication signal returning a maximum value (SSPmax), it comprises modulating the value of the electrical pulse (DP) outside the window (Vmin, vmax) of predetermined values in order to detect the presence of the object (T) to be charged.
2. 2. Method for detecting an object (T) to be charged by a charging device (D) according to claim 1, comprising at least one transmitting coil (B1, B2, B3), characterized in that for each coil the method comprises the steps of: a) Detecting the presence of an object on a charging surface (S) of the device; b) Checking the charging conditions (Q, Δr, Δl, Δfres); c) If the charging conditions are favorable: i) Transmitting an electrical pulse (DP) to the subject, the value of the electrical pulse (DP) being within a window (Vmin, vmax) of values predetermined during an authentication phase using the test receiver; ii) if in response the object emits a communication signal (SSP) below a maximum value (SSPmax), then the object (T) to be charged is detected, otherwise: iii) In the absence of a communication signal (SSP) or a communication signal returning to a maximum value (SSPmax), a modified electrical pulse (DPm) is then transmitted to the subject whose value lies outside a window of predetermined values: a. if, in response, the object emits a communication signal (SSP), then the object to be charged (T) is detected; b. Otherwise, a parasitic object is detected.
3. 3. A detection method as claimed in claim 2, characterized in that in the absence of the communication signal (SSP), the modified electrical pulse (DPm) has a voltage which is higher than an upper limit (Vmax) predetermined using the test receiver in the authentication phase.
4. 4. A detection method according to any one of claims 2 and 3, characterized in that the modified electrical pulse (DPm) has a voltage below a lower limit (Vmin) predetermined during the authentication phase using the test receiver if the object emits a communication signal of maximum value (SSPmax).
5. 5. A detection method according to any one of claims 2 and 3, characterized in that if the charging conditions (Q, Δr, Δl, Δfres) are unfavorable, the electrical pulse has a voltage below a lower limit (Vmin) predetermined using the test receiver in the authentication phase.
6. 6. A detection method according to any one of claims 2 and 3, characterized in that the method is stopped for a coil when the charging conditions (Q, Δr, Δl, Δfres) are unfavorable for the coil.
7. 7. A detection method according to any one of claims 2 and 3, characterized in that the charging device (D) comprises a plurality of transmitting coils (B1, B2, B3), the method being repeated for each coil.
8. 8. A detection method according to any one of claims 2 and 3, characterized in that it comprises a preceding step of calibrating the voltage value of the modified electric pulse (DPm) outside a window of predetermined values in accordance with various types of objects to be charged (T).
9. 9. A detection method according to any one of claims 2 and 3, characterized in that the checking of favorable charging conditions comprises measuring at least one parameter of the at least one transmitting coil (B1, B2, B3) and comparing said measurement with a predetermined threshold value of the same parameter obtained in advance for various types of objects to be charged (T).
10. 10. The detection method according to claim 9, characterized in that the parameter is the quality factor (Q) of the transmitting coil (B1, B2, B3), and/or the change in resistance (Δr) and/or the change in inductance (Δl), and/or the change in resonant frequency (Δfres).
11. 11. Device (D) for charging an object, comprising at least one transmitting coil (B1, B2, B3), characterized in that it comprises: a) A means (M1) for detecting an object on the charging surface (S); and, for each coil: b) Means (M2) for checking the charging conditions (Q, Δr, Δl, Δfres); c) Means (M3) for detecting the reception of a communication signal (SSP) and for comparing the value of said received communication signal with a maximum value (SSPmax); d) -means (M4) for modulating the value of the electrical pulse (DP) emitted by said at least one coil (B1, B2, B3) outside a window (Vmin, vmax) of values predetermined by the test receiver in the authentication phase, depending on the result of said checking and on the presence and/or value of the communication signal (SSP).
12. 12. The device for charging an object according to claim 11, characterized in that said means (M2) for checking the charging conditions (Q, Δr, Δl, Δfres) comprise means for measuring at least one parameter of the transmitting coil (B1, B2, B3) and means for comparing the measurement with a predetermined threshold value of the same parameter (Qmin, qmax, Δrmin, Δrmax, Δlmin, Δlmax, Δ Fresmin, Δ Fresmax) obtained in advance for the various types of object to be charged (T).
13. 13. Charging device (D) according to claim 12, characterized in that the parameter is the quality factor (Q) of the transmitting coil (B1, B2, B3), and/or the change in resistance (Δr) and/or the change in inductance (Δl), and/or the change in resonant frequency (Δfres).
14. 14. A computer program product comprising program code instructions for carrying out the steps of the detection method according to any one of claims 1 to 10 when said program is executed on a computer.
15. 15. A motor vehicle comprising a charging device (D) according to any one of claims 11 to 13.

Description

Method for detecting an object to be charged and associated charging device Technical Field The field of the invention is that of magnetic induction charging devices. In particular, the present invention relates to a method for detecting an object to be charged positioned close to a magnetic induction charging device and to an associated charging device. Background Magnetic induction charging technology is implemented in a system comprising a wireless charging device and an electrically stored battery to be charged in a mobile terminal, such as, for example, a portable item of user equipment, such as a mobile phone. The charging device comprises a transmission coil or a transmitting coil. The electrical storage battery includes a receiving coil to be charged. When the transmission coil and the receiving coil are positioned relative to each other, a change in the magnetic field generated by the transmission coil causes a current to flow in the receiving coil, thereby charging the electrical storage battery. The inductive charging technique meets the requirements of the standard, in this case the Qi standard of the wireless power alliance, also known as WPC standard. In order to detect the presence of an electrical storage battery comprising a receiving coil positioned relative to a transmission coil of a charging device, three steps are currently implemented. In a first step, the prior art method attempts to detect the presence of an object positioned relative to the charging device. For this purpose, an electrical pulse, also called "analog ping" or "AP", is sent at the charging frequency via the transmission coil of the charging device to the receiving coil. Analog ping is a continuous signal that exhibits periodic oscillations, with a period of, for example, 300 ms, and with an oscillation time of 5 to 20 ms. The voltage or impedance at the transmission coil terminals is observed. If a change in the voltage at the transmit antenna terminal or the transmit coil impedance is detected, then an object is present with respect to the transmit 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 there is a compatible object to be charged on the charging surface of the device. Digital ping is also an electrical pulse, but it requests a response from the object to be charged. This makes it possible to identify whether an 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. In particular, the detected object may be a parasitic object or a mobile device, such as a mobile phone equipped with a receiving coil for inductive charging. In this second step, efforts are then made to establish digital communication with the detected object in order to identify its characteristics. More particularly, an attempt is made to determine whether a detected object has a receiving coil for inductive charging in order to charge it. This communication is achieved by modulating the voltage amplitude across the transmit coil terminals in order to transmit electrical pulses (digital pings). In the event of an advantageous coupling between one of the transmitting coils and the receiving coil, the object to be charged then 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 that represents the coupling between its receiving coil and one of the transmitting coils of the charging device. The SSP communication signal corresponds to a ratio of a voltage of a rectifier converting an AC (alternating current) voltage of a receiving coil induced by receiving the digital ping to a DC voltage to a maximum voltage of the rectifier allowed by a manufacturer of an object to be charged. If the charging device does not receive the SSP communication signal, it considers that an object placed on the charging surface is a parasitic object, i.e., an object that is not compatible with charging, and inductive charging is not started. In particular, this occurs when the object to be charged is located in an area where the coupling between the transmitting coil and the receiving coil of the charging surface is too weak. In order to trigger the transmission of the SSP communication signal, according to Qi standard of the wireless power alliance, which is a global standard of inductive charging, the digital ping DP transmitted by the charging device should observe the level of the voltage induced in the object to be charged, which is set by the manufacturer, and this should be within a predetermined duration. More precisely, the digital ping should last between 65 ms and 93 ms. At this time, the voltage induced in the object to be charged should not exceed the threshold set by the manufacturer, and the cha