Auxiliary detection method for wireless charging system

Abstract

The invention discloses an auxiliary detection method for a wireless charging system. The auxiliary detection method comprises the steps that capacitors in a sensor group arranged at the ground end of the wireless charging system are sequentially connected to a working circuit; every time a capacitor is connected, the following steps are executed: a measurement step: a signal generator applies a group of alternating current signals with variable frequency in a working circuit, and correspondingly measures a group of working voltage values; a screening step: screening the alternating current signal with the highest working voltage value, and taking the frequency of the corresponding alternating current signal as the measurement resonant frequency; and a first judgment step: comparing the measured resonant frequency with a standard resonant frequency to judge whether a metal foreign body exists at the accessed capacitor. The metal foreign matter detection device has a function of detecting metal foreign matters, can directly and efficiently find the foreign matters by directly utilizing the influence of temperature on capacitance values, has higher detection precision, and is slightly interfered by the environment. Meanwhile, the mode is sensitive to temperature, and temperature detection can be achieved.

Description

technical field [0001] The invention relates to the field of wireless charging, in particular to a wireless charging auxiliary detection method. Background technique [0002] During wireless charging of electric vehicles, there is an open space between the power transmitting coil and the power receiving coil, and foreign objects made of metal may enter, and the alternating magnetic field during wireless charging power transmission will generate eddy currents in the metal foreign objects, causing the Metal foreign objects are heated to high temperature, causing potential risks such as burns and burning. Therefore, foreign object detection is a necessary function to ensure the safe operation of the wireless charging system. [0003] The most direct way to eliminate the risk caused by metal foreign objects is to measure the temperature on the surface of the transmitting coil. However, the common temperature sensors in the prior art, such as thermal resistors, can only measure t...

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Problems solved by technology

[0003] The most direct way to eliminate the risk caused by metal foreign objects is to measure the temperature on the surface of the transmitting coil. However, the common temperature sensors in the prior art, such as thermal resistors, can only measure the temperature of a certain contact point. It is also basically a metal material, which is also susceptible to the influence of the power transmission magnetic field

Patent CN110077247A-"Wireless Charging Foreign Object Detection System and Detection Method Based on Optical Fiber Sensing Network" proposes a wireless charging foreign object detection system and detection method based on an optical fiber sensor network that can work in a magnetic field, but there are foreign objects with low position resolution and the problem of low measurement accuracy

Patent CN110103745A-"A wireless charging metal foreign object detection device and detection method" proposes a device and a detection method for detecting foreign objects by exciting surface acoustic waves to detect temperature changes on the surface of the transmitting coil, but its measurement accuracy is also easily affected by environmental noise and medium Composition and other factors, so it is still necessary to propose a foreign matter detection method to improve the shortcomings of the current technology

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