Abstract: In order to solve the power supply problem of the oil field downhole water distributor, a wireless power transmission scheme with a coaxial solenoid type as an electromagnetic induction coupler was proposed, and the relationship between frequency and system output power under this condition was studied. The coupling coefficient of coaxial solenoid with uniform coupling medium and aligned two ends is related to the radius ratio of primary and secondary coils. In the tubing environment, the coupling coefficient is larger, and the influence of different natural resonance frequency and working frequency on the transmission power is greater in the case of series to series compensation. When the natural resonance frequency of the system is larger, the frequency splitting will occur. The working frequency can ensure that the system has high power output and transmission efficiency. Through simulation and experiment, the influence of natural resonance frequency and working frequency on power transmission is verified.

Key words: inductively coupled power transfer, oilfield water distributor, coaxial solenoid, transmission power  , frequency