Design of Axial DD Magnetic Coupling Structure Based on Rotary Steerable Drilling

A novel axial DD magnetic coupling structure is proposed in this paper to supply power to electrical equipment mounted on non-rotary steerable casing in rotary steerable drilling conditions. It can not only transmit electrical energy from the rotating side to the stationary side, but also effectively improve the axial anti-drift ability of the wireless energy transmission system. Firstly, the efficiency of the WPT system and the magnetic flux characteristics of the internal and external rotating WPT system are analyzed from the circuit model and the magnetic link model. Secondly, the axial DD magnetic coupling structure model is determined from two aspects of coil structure tiling diagram and three-dimensional diagram. Thirdly, the simulation tool and DD-4D double-layer orthogonal magnetic coupling structure were used to carry out the axial migration comparison test, and the mutual inductance variation characteristics were verified. Finally, an experimental model is established, and it is verified that when the axial offset distance is 2/3 of the model height, the mutual induction offset rate is only 63.6%. Compared with the DD-4D double-layer orthogonal magnetic coupling structure, the axial anti-deviation ability is improved by 26%.