WIRELESS CHARGING SYSTEM AND FOREIGN METAL OBJECT DETECTION METHOD THEREFOR

• US 20160190852A1
• Filed: 12/30/2014
• Published: 06/30/2016
• Est. Priority Date: 12/30/2014
• Status: Active Grant

• Current Assignee: Automotive Research & Testing Center
• Original Assignee: Automotive Research & Testing Center
• Inventors: CHIANG, Chao-Wen, WANG, Yu-Chuan
• Granted Patent: US 9,614,395 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 25/005 Circuits for comparing several input signals and for indicating the result of this comparison, e.g. equal, different, greater, smaller, or for passing one of the input signals as output signal
• CPC Class Codes: G01V 3/088 operating with electric fields G01V3/082 takes precedence
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection

Abstract

A wireless charging system includes a wireless charging device and a power-consuming device installed in a charging area. The wireless charging device has a signal conversion module connected to a controller, a transmitter antenna and a power input terminal. The power-consuming device has a receiver coil connected to a rectifier and outputting generated power through a power output terminal. Before or when the wireless charging device charges the power-consuming device, the controller of the wireless charging device can detect a power consumption status, voltage and current information and phase difference information of the transmitter antenna to instantly determine if any foreign metal object enters the charging area, thereby preventing high temperature generated by the foreign metal object from causing equipment damage and danger and enhancing wireless charging safety.

Claims

1. A foreign metal object detection method for a wireless charging system performed by a wireless charging device to transmit an electromagnetic signal to a power-consuming device, the method comprising steps of:

receiving at least one set of voltage and current information and phase difference information associated with the at least one set of voltage and current information of the wireless charging device;

determining if a variation of the at least one set of voltage and current information and a variation of the phase difference information fall outside a safe range; and

performing an emergency response measure when the variation of the at least one set of voltage and current information and the variation of the phase difference information fall outside the safe range.

2. The method as claimed in claim 1, wherein after the step of receiving at least one set of voltage and current information and phase difference information associated with the at least one set of voltage and current information, the method further comprises a step of acquiring a real impedance value corresponding to the at least one set of voltage and current information.

3. The method as claimed in claim 2, wherein when performing the step of determining if a variation of the at least one set of voltage and current information and a variation of the phase difference information fall outside a safe range, the method further comprises steps of:

simultaneously determining if the real impedance value and the phase difference information associated with the at least one set of voltage and current information are respectively greater than a first safety threshold and a second safety threshold; and

performing an emergency response measure when the real impedance value and the phase difference information associated with the at least one set of voltage and current information are respectively greater than the first safety threshold and the second safety threshold.

4. The method as claimed in claim 3, wherein when performing the step of performing an emergency response measure, the method further comprises a step of sending out a stop signal and sending out an alarm signal from the wireless charging device.

5. The method as claimed in claim 1, wherein the at least one set of voltage and current information has a first cycle, a second cycle, and the phase difference information associated with the at least one set of voltage and current information is calculated according to a ratio of the first cycle over the second cycle.

6. A wireless charging system, comprising:

a wireless charging device having;

a transmitter controller;

a transmitter antenna;

a signal conversion module connected to the transmitter controller and the transmitter antenna, and driving the transmitter antenna to transmit electromagnetic signals for the transmitter controller to detect a power consumption status, voltage and current information and phase difference information associated with the voltage and current information of the transmitted antenna; and

a power-consuming device having;

a rectifier;

a receiver controller connected to the rectifier;

a receiver coil connected to the rectifier, sensing the electromagnetic signals transmitted from the transmitter antenna of the wireless charging device in generation a current, and outputting the current to a power output terminal through the rectifier;

wherein when determining that the voltage and current information and the phase difference information associated with the voltage and current information fall outside a safe range, the transmitter controller of the wireless charging device transmits a control signal to the signal conversion module to stop the transmitter antenna from transmitting the electromagnetic signals.

7. The wireless charging system as claimed in claim 6, wherein the signal conversion module has:

a first signal converter connected to the transmitter antenna and the transmitter controller; and

a second signal converter connected between the first signal converter and a power source.

8. The wireless charging system as claimed in claim 7, wherein

the wireless charging device further has a first communication module connected to the transmitter controller;

the power-consuming device further has a second communication module connected to the receiver controller and establishing a link with the first communication module of the wireless charging device using a communication protocol.

9. The wireless charging system as claimed in claim 8, wherein the first signal converter pertains to a DC (Direct Current) to AC (Alternating Current) converter, and the second signal converter pertains to an AC to DC converter.

10. The wireless charging system as claimed in claim 9, wherein the transmitter controller of the wireless charging device is connected to an emergency stop module, and the receiver controller of the power-consuming device is connected to another emergency stop module, a man machine interface, an energy management system or a vehicle control unit.