The problem of high-order nonlinearity in the transient process of a wireless power transmission system is a difficulty in load measurement and identification.When dealing with beat-frequency signals due to the high-order nonlinearity,there are some problems in the existing analog envelope detection method,such as signal distortion,poor circuit flexibility,and limited measurement range.Aimed at these problems,a digital envelope detection method was proposed based on Hilbert transform,and a digital envelope detector was designed to extract the envelope of the voltage beat-frequency signal.In addition,simulations and experiments were conducted to validate the proposed method.Results show that this method can accurately extract the envelope of the voltage beat-frequency signal with different loads,and it achieved an error of less than 5％in the load resistance range of 1-2 000 Ω.The proposed method extends the contactless load measurement range based on characteristic parameters in the transient process,providing a new idea for measuring the internal resistance of batteries in aircraft such as unmanned aerial vehicles.
关键词
无线能量传输/负载测量与辨识/希尔伯特变换/数字包络检波
Key words
Wireless power transmission/load measurement and identification/Hilbert transform/digital envelope detection
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